RCN 213-210-06-08 

ffigh S02 Removal Efficiency Testing 

DE-AC22-92PC91338 

I M Topical Report 

Results of Sodium Formate Additive Tests at 

New York State Electric & Gas Corporation's 

Kintigh Station 

Prepared for: 

Janice Murphy 

U.S. Department of Energy 

Pittsburgh Energy Technology Center 

P.O. Box 10940 

Pittsburgh, PA 15236 

Prepared by: 

Radian Corporation 

P.O. Box 201088 

Austin, TX 78720-1088 

14 February 1997 

T 

DISTR!BUT!ON OF THIS DOCUMENT IS UNLIMITEDU 
----------------------------------
DISCLAIMER 

Portions of tbis document may be Dlepole 

ill electronic jmage products. . Images are 

produced from the best available original 

document. 

TABLE OF CONTENTS 

Page 

SUMMARY ............. , ..................................... S;..1 

1.0 INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 

1.1 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1 

1.2 Project Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2 

1. 3 Report Organization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3 

2.0 TEST CONDITIONS AND RESULTS ............................ 2-1 

2.1 FGD System Description ................................. 2-1 

2.2 Test Approach . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 

2.2.1 Baseline Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4 

2.2.2 Parametric Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5 

2.2.3 Sodium Formate Consumption Test ..................... 2-6 

2.3 Test Measurements ..................................... 2-7 

2.3.1 Flue Gas Sampling ................................ 2-7 

2.3.2 Slurry Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8 

2.3 .3 Chemical Analyses of Slurry and Filtrate Samples . . . . . . . . . . . . 2-9 

2.3.4 Other Process Data ..................... ,, . . . . . . . . . 2-10 

2.4 S02 Removal Efficiency Test Conditions and Results . . . . . . . . . . . . . 2-10 

2.4.1 Baseline Test S02 Removal Efficiency . . . . . . . . . . . . . . . . . . 2-10 

2.4.2 Baseline Test CEM Traverse Data . . . . . . . . . . . . . . . . . . . . . 2-13 

2.4.3 Sodium Formate Parametric Test S02 Removal Efficiency . . . . . 2-13 

2.4.4 S02 Removal Performance Correlations . . . . . . . . . . . . . . . . . 2-17 

2.5 Results of Slurry Sample Chemical Analyses . . . . . . . . . . . . . . . . . . . 2-19 

2.5.1 Solid-Phase Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19 

2.5.2 Liquid-Phase Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25 

2.6 Sodium Formate Consumption Test Conditions and Results . . . . . . . . . 2-26 

2.6.1 Consumption Rate Calculation . . . . . . . . . . . . . . . . . . . . . . . 2-26 

2.6.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28 

2.7 Effect of Sodium Formate Additive on Solids Dewatering Properties . . . 2-32 

2.7.1 Settling Test Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-32 

2. 7.2 Filter Leaf Tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-36 

2.7.3 Scanning Electron Microscope (SEM) Photographs . . . . . . . . . . 2-36 

2.8 Other Process Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42 

2.8.1 Control Room Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42 

2.8.2 Recycle Pump Slurry Flow Rate Measurements . . . . . . . . . . . . 2-42 

i 
TABLE OF CONTENTS (Continued) 

Page 

2.8.3 S02 Removal Data for the Consumption Test. . . . . . . . . . . . . . . . . . . . . . . . 2-42 

3.0 FGDPRISM MODELING RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1 

3.1 FGDPRISM Calibration Results ............................ 3-1 

3.2 Predictive Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2 

4.0 ECONOMIC EVALUATION .................................. 4-1 

4.1 Upgrade Options and Cost Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-1 " 

4.2 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4 

4.2.1 Effect of Sodium Formate Additive Price on Results . . . . . . . . . . 4-8 

4.3 Recommended Upgrade Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8 

APPENDIX A: 

APPENDIXB: 

APPENDIXC: 

APPENDIXD: 

APPENDIXE: 

Detailed S02 Removal Data and Chemical Analyses Results for 

Baseline and Parametric Tests .................... A-1 

Detailed Formate Material Balance Data and Chemical Analyses 

Results for the Sodium Formate Consumption Test . . . . . . B-1 

Other Process Data . . . . . . . . . . . . . . . . . . . . . . . . . . . C-1 

FGDPRISM Calibration . . . . . . . . . . . . . . . . . . . . . . . . D-1 

Detailed Economic Calculations . . . . . . . . . . . . . . . . . . . E-1 

ii 
2-1 

LIST OF FIGURES 

Flow Diagram of New York State Electric and Gas Kintigh Station's 

FGDSystem 

Page 

2-2 

2-2 Results ofCEM Traverses at Module E outlet (ppm S02 dry) ................. 2-14 

2-3 Adjusted NTU vs. Formate Concentration for Tests at pH= 5.6 ............... 2-20 

2-4 Adjusted NTU vs. pH for Tests with 1000 ppm Formate ..................... 2-21 

2-5 Baseline Test Limestone Utilization vs. Slurry pH ......................... 2-23 

2-6 Parametric Tests Limestone Utilization vs. Slurry pH ....................... 2-24 

2-7 Comparison of Baseline and Long-Term Tests Limestone Utilization .......... 2-33 

2-8a. Solids from Baseline Test 1 (500x) ..................................... 2-38 

2-8b. Solids from Baseline Test 1 (1 OOOx) .................................... 2-38 

2-9a. Solids from Parametric Test 1 (500x) .................................... 2-39 

2-9a. Solids from Parametric Test 1 (lOOOx) ................................... 2-39 

2-10a. Solids from Parametric Test 2 (500x) .................................... 2-40 

2-10b. Solids from Parametric Test 2 (lOOOx) ................................... 2-40 

2-lla. Solids from Parametric Test 9 (500x) .................................... 2-41 

2-llb. Solids from parametric Test 9 (1000x) ................................... 2-41 

3-1 Kintigh FGDPRISM Calibration: Predicted vs. Observed Removal ............. 3-3 

iii 
LIST OF TABLES 

Page 

2-1 Average Baseline Test Conditions and Results ............................ 2-11 

2-2 Average Sodium Formate Parametric Test Conditions and Results ............. 2-15 

2-3 Summary of Sodium Formate Consumption Test Results 2-29 

2-4 Results of Settling Tests .............................................. 2-35 

2-5 Results of Filter Leaf Tests ............................................ 2-37 

2-6 Results of Recycle Pump Flow Measurements ............................. 2-43 

2-7 S02 Removal Efficiency During Consumption Test ........................ 2-44 

4-1 Economic Basis for Kintigh S02 Removal Upgrade Options ................... 4-2 

4-2 Economic Comparison of S02 Removal Upgrade Options .................... 4-5 

DISCLAIMER 

This report was prepared as an account of work sponsored by an agency of the United Sta~ 

Government. Neither the United States Gl)vernment nor any agency ther~f, .n~r any of thet_r 

employees, makes any warranty, express or implied, or ass~mes any_ legal hablltty or respon:; 

bility for the accuracy, completeness, or usefulness of ~y ~nform~uon, apparatus: product, • 

process disclosed, or represents that its use would not mfnnge ~nvately owned nghts. Refer 

ence herein to any specific commercial product, process, or service by _trade name, trademark, 

manufacturer. or otherwise does not necessarily constitute or imply 1ts endorsement, r~m· 

mendation, or favoring by the United States Government o_r any agency thereof. The vtews 

and opinions of authors expressed herein do not necessanly state or reflect those of the 

United States Government or any agency thereof. 

iv 
SUMMARY 

Tests were conducted at New York State Gas & Electric's (NYSEG's) Kintigh 

Station to evaluate options for achieving high sulfur dioxide (S~) removal efficiency in the 

wet limestone flue gas desulfurization (FGD) system. This test program was one of six 

conducted by the U.S. Department of Energy to evaluate low-capital-cost upgrades to existing 

FGD systems as a means for utilities to comply with the requirements of the 1990 Clean Air 

Act Amendments. The upgrade option tested at Kintigh was sodium formate additive. 

Results from the tests were used to calibrate the Electric Power Research 

Institute's (EPRI) FGD PRocess Integration and .Simulation Model (FGDPRISM) to the 

Kintigh scrubber configuration. FGDPRISM was then used to predict system performance for 

evaluating conditions other than those tested. An economic evaluation was then done to 

determine the cost effectiveness of various high-efficiency upgrade options. These costs can be 

compared with the estimated market value of S02 allowances or the expected costs of 

allowances generated by other means, such as fuel switching or new scrubbers, to arrive at the 

most cost-effective strategy for Clean Air Act compliance. Results from the test program at 

Kintigh are summarized below. 

SQ2 Removal Performance. Baseline tests on one module ofNYSEG's 

Kintigh Station wet limestone FGD system showed that the S~ removal efficiency at normal 

full-load operating conditions (pH 5.6, flue gas velocity = 9 ftls, four recycle pumps 

operating) was about 86%. Tests with sodium formate additive showed that the SOz removal 

efficiency could be increased to as high as 99.4% with a formate ion concentration of 3800 

mg/L in the recycle slurry. The sodium formate additive had no significant effect on process 

chemistry or on the dewatering properties of the calcium sulfite byproduct solids. 

Sodium Formate Additive Consumption. In a long-term sodium formate 

consumption test with sodium formate added to the entire FGD system, an average additive 

S-1 
feed rate of 168 lb/hr (as sodium formate) was required to maintain an average concentration 

of 1080 mg/L formate ion in the recycle slurry at full-load operation. At this formate 

concentration, S02 removal efficiency averaged about 97% . The total sodium formate additive 

consumption rate was 16.6lb/ton of S02 removed. Of the total formate consumed, 12% was 

lost with the filter cake liquid, about 32% was lost by precipitation with the filter cake solids, 

about 6% was lost by vaporization into the flue gas, and the remaining 50% was attributed (by 

difference) to oxidative degradation . 

.802 Removal Upgrade Economics. The economics of sodium formate addition 

were evaluated based on a capital cost of $300,000 for a 100 lb/hr additive storage and 

delivery system, and using operating cost data provided by NYSEG. Using sodium formate 

additive at 1000 mg/L in the recycle slurry, more than 10,000 additional tons per year of S02 

could be removed by the Kintigh FGD system at an average additional cost of only $76/ton. 

Depending on the assumed value of S02 allowances ($150 to $250/ton), the estimated net 

annual value of additional S02 removal at Kintigh ranged from $0.8 to $1.8 million. 

Further analysis, based on performance predictions using FGDPRISM, 

suggested that sodium formate additive could be used to maintain the current 85% average S02 

removal (with partial bypass) while operating fewer recycle pumps, resulting in a net annual 

savings of about $100,000. FGDPRISM also predicted that a significant performance 

improvement could be obtained by operating with a rmer limestone grind. This might be done 

by operating the reagent preparation equipment at a lower throughput for two shifts per day 

instead of one shift per day. Some modifications to the ball mill classifier would also be 

required. 

S-2 
1.0 INTRODUCTION 

This report describes the results of tests conducted at New York State Gas & 

Electric's (NYSEG's) Kintigh Station to evaluate options for upgrading the flue gas 

desulfurization (FGD) system's S02 removal efficiency using sodium formate additive. The 

objective of these tests was to obtain performance data needed to evaluate the cost effectiveness 

of upgrading an existing FGD system as part of a strategy for meeting requirements of the 1990 

Clean Air Act Amendments. 

1.1 Background 

Provisions of the Clean Air Act Amendments of 1990 call for a ten-million ton 

per year reduction in U.S. S02 emissions (from a 1980 baseline) in two phases. Phase I calls for 

a five-million ton per year reduction by 1995, and the remainder of the reductions are to be 

completed by the year 2000 for Phase IT. Affected utilities have a number of options for 

achieving these reductions, such as switching to lower sulfur-content coals, installing new FGD 

systems, and improving the S02 removal performance of existing FGD systems. Some utilities 

may employ a combination of these and other options as part of an overall compliance strategy. 

The Flue Gas Cleanup (FGC) Program at the U.S. Department of Energy 

Pittsburgh Energy Technology Center (DOE PETC) helps to maintain and foster the widespread 

use of coal by developing technologies that will mitigate the environmental impacts of coal 

utilization. The program focuses on post-combustion technologies for the control of S02, oxides 

of nitrogen, particulate matter, and air toxics generated from coal combustion. A portion of the 

FGC Program, including this project, involves enhancing the S02 removal efficiencies of existing 

wet FGD systems. The results from this project will allow utilities to better consider enhanced 

performance of existing FGD systems as an option for achieving compliance with Phase I and/or 

Phase IT of the Clean Air Act Amendments. 

1-1 
In this project, Radian Corporation is conducting tests at six full-scale FGD 

systems to evaluate options for achieving high S02 removal efficiencies (95 to 98% removal). 

Each system is being characterized under baseline operation and then with additives or with other 

modifications to enhance S02 removal performance. 

The systems being evaluated are at Tampa Electric Company's Big Bend Station, 

Hoosier Energy's Merom Station, Southwestern Electric Power Company's Pirkey Station, PSI 

Energy's Gibson Station, Duquesne Light Company's Elrama Station, and the New York State 

Electric and Gas Corporation's (NYSEG) Kintigh Station. A wide variety of FGD system 

vendors and designs are represented in the program. Most of these systems were designed to 

achieve 85 to 90% so2 removal. 

This Topical Report covers only results from the sixth site, at NYSEG's Kintigh 

Station. Separate Topical Reports have been issued for each of the other sites. 

1.2 Project Description 

Three types of performance tests were completed at Kintigh. First, "baseline" 

tests were done to obtain performance data without the sodium formate additive. Then, 

"parametric" tests were done to evaluate performance using the additive at various 

concentrations. The baseline and parametric tests were done using only one of the four operating 

absorber modules. Following the parametric tests, a steady-state sodium formate consumption 

test was done by adding sodium formate to the entire FGD system. 

Under a separate project funded by the Electric Power Research Institute, their 

FGD PRocess Integration and ~imulation Model (FGDPRISM) was calibrated to the Kintigh 

FGD system configuration. The calibrated FGDPRISM model was then used to predict system 

performance for evaluating conditions other than those tested. 

1-2 
Actual performance results, along with the steady-state sodium formate 

consumption data and pertinent cost information provided by NYSEG, were used as the basis for 

an economic evaluation. In this evaluation, the net cost of additional tons of S02 removal was 

estimated for different operating conditions and formate concentrations. These costs can be 

compared with the estimated market value of S02 allowances or the expected costs of allowances 

generated by other means, such as fuel switching or new scrubbers, to arrive at the most costeffective strategy for Clean Air Act compliance. 

1.3 Report Organization 

The performance tests are described and results are presented in Section 2 of this 

topical report. The FGDPRISM calibration and performance predictions are discussed in Section 

3, and the economic evaluation is addressed in Section 4. Detailed results and calculations are 

included as Appendices A through E. 

1-3 

2.0 TEST CONDITIONS AND RESULTS 

This section describes the full-scale FGD system tests conducted at the NYSEG 

Kintigh Station and provides an overview of the results. The tests evaluated methods for 

achieving high S02 removal efficiency with the Kintigh FGD system and followed a 

methodology used for the other sites included in this DOE-PETC program. 

This section presents and discusses results from each of these three phases of 

testing at Kintigh. In Section 2.1, the FGD system is briefly described. The test approach and 

measurement methods are outlined in Sections 2.2 and2.3. Results of the short-term baseline 

and sodium formate parametric tests are presented in Sections 2.4 and 2.5. Results of the systemwide sodium formate consumption test are described in Section 2.6. Following this, the effects 

of sodium formate additive on FGD byproduct solids is discussed in Section 2.7, and other 

process measurements are summarized in Section 2.8. I 

2.1 FGD System Description 

The NYSEG Kintigh Station is located in Niagara County near Barker, New York. 

Figure 2-1 is a simplified flow diagram for the Kintigh FGD system showing the arrangement of 

a single absorber module. Flue gas exits the boiler and passes through electrostatic precipitators 

(ESPs) for particulate control. From the ESPs, flue gas goes through three parallel ID fans and 

then to the FGD system. At full load, four modules are required to treat flue gas from 700 MW 

of generating capacity. There are two additional spare modules. 

The absorber modules are Peabody open spray towers. In this configuration, flue 

gas enters the side of the vessel near the bottom and flows upward. A recirculating slurry is 

sprayed downward, countercurrent to the gas flow, through up to five levels of spray headers. 

Each spray header level on the absorber has its own recycle pump. The combined liquid-to-gas 

ratio (UG) is about 116 gal/1 000 acf, with all five headers in service on each of four operating 

modules at the full-load flue gas flow rate. However, only four headers per absorber module are 

2-1 
tv 

I 

tv 

Bypass 

I 

I 

Flue Gas 

FromESPs 

To 

Hydroclones 

Fresh 

...,..... ....,... ....,... 1.. 'Water 

Pump4 

Pumpl 

PumpS Pump2 Pump 

Process 

Hydroclones 

1,. 1 F

R

To Vacuu

Filters 

.------------, _j 

1 r Limestone 

Fresh 

Water 

+ 

Inlet Wall 

Wash 

Hydroclone 

Feed Pump 

Recycle 

Pump 

+. . I 

Secondary 

Reaction Tank t=Jal 

Waste Slurry Sump 

Supern

Tank 

Figure 2-1. Flow Diagram of New York State Electric and Gas Kintigh Station's FGD Sy
typically required to achieve S02 emissions compliance (0.6 lb SO/million Btu), which is 

equivalent to about 85% overall S02 re~oval. 

Mter leaving the spray section, the flue gas flows past a sieve tray to a verticalgas-flow mist eliminator. From the mist eliminator, flue gas exits the top of the absorber 

module. The combined absorber exit gases then flow to the stack through a common outlet duct. 

The FGD system is equipped with an absorber bypass duct. However, nearly all of the flue gas 

from the boiler is typically treated in the absorbers, and the stack operates in a "wet" mode. A 

small amount of flue gas is bypassed to prevent excess condensation in the absorber outlet 

plenum. 

The reagent used in the FGD system is a slurry of ground limestone. The 

limestone is ground in ball mills, and the prepared slurry is stored in two slurry feed tanks, from 

which it is added to the absorbers to maintain the recirculating slurry pH set point. Elemental 

sulfur emulsion is also added to the limestone slurry feed tanks to produce thiosulfate ion in the 

absorber reaction tanks, to serve as an oxidation inhibitor. 

The recirculating slurry drains from the absorber into a secondary reaction tank 

external to the tower. In the secondary reaction tank, fresh limestone slurry is added to control 

the recirculating slurry pH. Slurry from the secondary reaction tank then flows by gravity to the 

primary reaction tank, which is integral to the bottom of the absorber. The slurry recirculation 

pumps draw suction from the primary reaction tanks. 

Slurry from the primary reaction tank is also recirculated to hydroclones. A 

portion of the low-solids-content overflow from the hydroclones is used to wash the underside of 

the sieve tray below the mist eliminators. The remainder is routed to a baffled section in the 

primary reaction tank in the base of the absorber, from which it overflows to a waste sump along 

with a portion of the slurry from the primary reaction tank. The high-solids-content underflow 

from the hydroclones falls into the external, secondary reaction tank. 

2-3 
Waste slurry overflows from the primary reaction tank on each absorber to a waste 

slurry sump, where it is combined with a small bleed stream from the secondary reaction tanks 

and some recycled thickener overflow. This mixed waste stream is fed to two thickeners. Liquor 

overflow from the thickeners flows to a supernate tank, and the underflow is pumped to slurry 

storage tanks and then to vacuum filters. The filtrate from the vacuum filters is returned to the 

thickeners. Supernate is returned to the absorbers by being used in the limestone grinding circuit 

and by makeup to the secondary reaction tanks. The slurry density in the modules is controlled 

by adjusting the rate of supernate return. The primary makeup of fresh water to the FGD system 

is via the mist eliminator wash and pump seals. Additional makeup is added to the supernate 

tank to maintain system liquid level. 

The dewatered FGD sludge is blended with lime and fly ash from the ESPs for 

stabilization before being landfilled on the site. The solids content of the dewatered FGD sludge 

is approximately 7 5 weight percent. 

2.2 Test Approach 

The baseline and parametric tests were conducted on a single module (Module E) 

of the FGD system. Module performance was measured by sampling the flue gas at the inlet and 

outlet. Slurry samples from the reaction tank were obtained concurrently with the flue gas 

samples. Sampling locations are indicated on Figure 2-1. 

2.2.1 Baseline Tests 

For the baseline tests, independent variables included primary reaction tank pH, 

liquid-to-gas ratio (UG), which was varied by changing the number of recycle pumps in service, 

and flue gas velocity in the test module. The four operating modules receive flue gas from a 

common plenum so that the flue gas flow to the test module could not be independently 

controlled. During the baseline tests, a constant high load was maintained and the flue gas flow 

to the test module varied only slightly depending on the number of operating pumps. One 

2-4 
baseline test was conducted with five operating modules to investigate the effect of changing flue 

gas velocity. 

The baseline tests began with a two-day test at NYSEG's normal operating 

conditions. This test duration was sufficient to approach steady-state operating conditions with 

respect to solids properties in the test module. The performance measurements during the twoday test included S02 removal, limestone utilization, sulfite oxidation, solids dewatering 

properties, and relative saturations for precipitating and dissolving species. 

The two-day test was followed by a series of half-day tests during which only S02 

removal and limestone utilization were expected to represent steady-state conditions. During the 

half-day tests, the slurry pH set point and number of operating spray pumps were varied. During 

the final baseline test, the flue gas velocity in the test module was deliberately lowered by 

operatiug a spare module. 

2.2.2 Parametric Tests 

For the parametric tests, independent variables included reaction tank pH, number 

of recycle pumps in service, and sodium formate additive concentration. Flue gas velocity was 

not intentionally varied during the parametric tests, but the unit load varied substantially during 

this test series. The flow to the test module was controlled to the extent possible by varying the 

number of operating modules and by manually adjusting the module inlet dampers, but the flue 

gas velocity in the test module actually varied from 6.0 to 9.3 ft/s. 

Three two-day tests (Tests 1, 2, and 9) were done at three increasing sodium 

formate levels so that the effect of sodium formate on steady-state performance could be 

measured. For these two-day tests, performance measurements included S02 removal, limestone 

utilization, sulfite oxidation, solids dewatering properties, and relative saturations of limited 

solubility species such as gypsum. A series of half-day tests (Tests 3 through 8) were completed 

at the mid-level formate concentration to investigate the effects of slurry pH and number of 

2-5 
operating pumps on 802 removal. A final half-day test was done at a high sodium formate 

concentration to determine the maximum 802 removal capability of the test module. 

For the parametric tests, sodium formate was fed continuously to the test module 

reaction tank to maintain the desired concentration during and between tests. The sodium 

formate concentration was measured prior to each test and adjusted if necessary by pumping 

additional sodium formate from the tanker into the reaction tank. 

2.2.3 Sodium Formate Consumption Test 

The parametric tests were followed by a steady-state sodium formate consumption 

test. The objective of the consumption test was to measure the amount of sodium formate 

required to maintain high S02 removal efficiency with the entire FGD system. Sodium formate 

was added to the reaction tanks of each of the four operating modules and to the A and B 

thickeners to bring the entire system formate concentration to approximately 1000 mg/L (as 

formate ion). Sodium formate was then added continuously to the waste slurry sump to maintain 

this system-wide concentration until the conclusion of the consumption test. 

The sodium formate consumption rate was determined by liquid-phase material 

balance. The amount of formate added was carefully measured by gauging the tanker. The most 

straightforward and predictable loss of sodium formate from the system is with the liquor that 

remained adhered to the byproduct solids ("solution loss"). This loss rate was determined by 

measuring the filter cake moisture content and the formate concentration in that moisture, and by 

quantifying the filter cake production rate. The difference between the amount added and the 

amount lost with the filter cake, plus an "accumulation" term which accounts for changes in 

sodium formate concentrations in the system over the test duration, yielded the total amount of 

formate consumed by other mechanisms, including vaporization, precipitation, and oxidization. 

Formic acid vaporization was measured independently by flue gas analysis and formate 

precipitation was measured by analysis of the filter cake solids. Thus, the formate oxidation rate 

could be determined by difference. 

2-6 
For at least one hour during each day of the formate consumption test, the bypass 

damper was closed so that S02 removal efficiency could be determined using the inlet and stack 

continuous emissions monitors. 

2.3 Test Measurements 

2.3.1 Flue Gas Sampling 

The primary performance measurements obtained at the site included inlet and 

outlet flue gas S02 concentrations and flue gas velocity for the test module. Inlet concentrations 

were determined using NYSEG's existing on-line certified S02 analyzer. The relative accuracy 

of this analyzer was verified by pre-test EPA Method 6 samples at the module inlet. Module 

outlet S02 concentrations were measured using a modified EPA Method 6 with a composite flue 

gas sample obtained by a 24-point isokinetic traverse of the module outlet duct. The total test 

module gas flow rate was measured during the same traverse. During some of the baseline tests, 

the outlet flue gas S02 concentrations were also measured at the individual traverse points using 

a portable flue gas analyzer. 

During a typical half-day test, the performance of the test module was measured 

by completing duplicate flue gas so2 and velocity traverses at the module outlet, while inlet so2 

concentrations were recorded at five-minute intervals and averaged over the duration of each 

outlet traverse. For tests with longer durations, the half-day gas sampling schedule was repeated, 

so that up to eight individual gas measurements were obtained during a two-day test. 

Flue gas S02 concentrations were determined on site from the Method 6 samples 

using the barium perchlorate titration procedure. These on-site data were used to verify that test 

results were consistent and reasonable and to make testing decisions. The Method 6 impinger 

solutions were also analyzed off site by ion chromatography as a quality control check and to 

improve the accuracy of results for tests at very high S02 removal efficiency. 

2-7 
During selected parametric tests, the concentration of formic acid in the flue gas 

was also determined by drawing a measured amount of flue gas through an impinger train 

containing dilute sodium hydroxide. The amount of formic acid captured in the impinger 

solution was then determined by ion chromatography. 

2.3.2 Slurry Sampling 

During the baseline and parametric tests, slurry samples were obtained from the 

test module by sampling at the hydroclone feed location, which is the sampling point used by 

NYSEG for routine process monitoring. The slurry samples were timed to coincide with the 

Method 6 outlet flue gas traverses. 

At the beginning of each set of duplicate outlet S02 traverses, the slurry pH was 

measured using a calibrated portable pH meter, and a slurry sample was obtained. In the time 

between each set of duplicate traverses, the pH was again measured, another slurry sample was 

obtained, and a set of diluted, stabilized filtered liquor samples was also obtained. At the 

conclusion of each set of duplicate flue gas S02 traverses, the pH was again measured and a final 

slurry sample was obtained. 

During the second day of each two-day test, slurry samples were also obtained for 

dewatering tests. Settling rate tests were conducted on site with slurry samples at process 

temperature. Samples were also collected at the same time for off-site filter leaf tests. 

During the formate consumption test, samples were obtained from the major 

system vessels to monitor the formate concentration. Formate was measured on site by buffer 

capacity titration. Samples were also obtained for off-site analysis by ion chromatography. 

Sufficient data were obtained to determine the formate consumption rate by material balance 

calculations. Slurry and filtered liquor samples were also obtained from the operating modules 

during the consumption test to document any effects of sodium formate additive on the process 

chemistry during the week of operation in this mode. 

2-8 
2.3.3 Chemical Analyses of Slurry and Filtrate Samples 

The number of solid and liquid chemical analyses made depended on the 

importance of the results to the performance evaluation and on the expected time constants for 

changes in concentrations of the various species. 

All of the slurry samples were analyzed for weight percent solids content and 

solid-phase carbonate. These results were used to calculate limestone utilization, which is an 

important performance parameter. Limestone utilization can change relatively quickly with 

operating pH. 

Complete solid-phase analyses including calcium, magnesium, sulfite, sulfate, and 

carbonate were done only for the slurry samples that were collected at the midpoint of each set of 

duplicate Method 6 traverses. The complete solid-phase analyses were used to calculate the 

sulfite oxidation fraction. This is also an important performance parameter, but the time constant 

for changes in slurry sulfite/sulfate content in the reaction tank is much longer than that for 

carbonate content. Therefore, it was not necessary to measure oxidation fraction as frequently as 

limestone utilization. The oxidation fraction is also not as sensitive to minor changes in 

operating pH as the limestone utilization. 

Slurry solids samples from the two-day baseline test and from each of the two-day 

parametric tests were examined and photographed using scanning electron microscopy. 

All of the filtered slurry liquid samples were analyzed for liquid-phase calcium, 

sulfite, sulfate, and carbonate. These results were used to estimate relative saturations for the 

precipitating and dissolving species. Relative saturations are important process chemistry 

indicators that can change relatively quickly with changes in operating conditions, especially pH. 

Only one liquid sample per day was analyzed for soluble species such as magnesium, sodium, 

chloride, and thiosulfate. The time constant for changes in soluble species concentrations is 

2-9 
usually on the order of weeks. Therefore, these concentrations were not expected to vary 

significantly during a test day. 

Filtered slurry liquid samples from the two-day baseline test and from each of the 

two-day parametric tests were analyzed for 32 elements using inductively-coupled plasma 

emissions spectroscopy (ICPES). 

2.3.4 Other Process Data 

Other process data including boiler load, ID fan motor current, recycle pump 

discharge pressures and motor current, FGD system temperatures and pressures, and stack CEM 

data were either logged automatically by the plant data acquisition system or recorded from local 

indicators as required. Flow rates of individual slurry recycle pumps on the test module were 

also measured using a portable ultrasonic flow meter. 

2.4 802 Removal Efficiency Test Conditions and Results 

2.4.1 Baseline Test 802 Removal Efficiency 

Table 2-1 summarizes the average test conditions and S02 removal efficiency 

results for the baseline tests. More detailed test data for the individual Method 6 traverses are 

included in Appendix A, Table A-1. In both tables, the "slurry pH" is that measured with a 

calibrated portable meter. In most cases (except Test 6), the portable meter agreed closely with 

the control room indicator. The "flue gas velocity" was calculated from the outlet duct pitot 

traverse, adjusted to the scrubber cross sectional area. The number of operating recycle pumps is 

shown for each test. Several slurry flow measurements were made for each recycle pump during 

the baseline test period. The "UG" for each test was calculated using the average recycle pump 

flow rates and the average measured flue gas volume. The "inlet S02" for each test is the average 

of inlet CEM readings recorded every five minutes during the outlet flue gas traverses. 

2-10 
Table 2-1 

Average Baseline Test Conditions and Results 

1 5.63 9.0 4 86 1549 86.2 

2 5.57 8.8 5 110 1526 92 

3 5.59 9.8 3 61 1530 78.5 

4 5.02 9.4 3 63 1804 68.5 

5 5.18 8.7 5 110 1729 84.7 

5A 4.94 9.4 4 82 1697 74 

6 5.65* 9.3 3 63 1692 88.3 

7 5.82 8.5 5 113 1708 96.1 

* This pH reading is questionable. 

2-11 
The baseline test series began with a two-day test at normal operating conditions 

(four modules on line, pH set point at 5.6, and four spray pumps operating per module). For this 

test at normal operating conditions, the S02 removal efficiency averaged about 86%. 

For Tests 2 and 3, the pH set point remained at 5.6, and the number of operating 

pumps was varied (five pumps for Test 2 and three pumps for Test 3). The flue gas velocity 

changed slightly when the number of pumps was changed. Operation with five pumps increased 

· S02 removal to an average of 92%, and operation with three pumps decreased removal to about 

79%. 

For Tests 4, 5, and SA, the pH set point was lowered to 5.2, and the number of 

operating pumps was varied. At this low pH set point, the S02 removal efficiency averages 

ranged from about 68% with three pumps operating to 85% with five pumps operating. 

The pH set point was increased to 5.8 for Tests 6 and 7. This was the highest pH 

that could be maintained by the limestone delivery system. Some difficulty in measuring the pH 

was encountered during Test 6. The portable meter was reading about 0.2 units lower than the 

on-line meter, even though they had agreed closely in all of the previous tests. At the high pH set 

point, the S02 removal efficiency ranged from 88% with three pumps operating to 96% with five 

pumps operating. 

The final test, Test 8, was completed at the normal pH set point of 5.6, with five 

modules on line and five pumps operating to lower the gas velocity in the test module. This 

decreased the flue gas velocity from the normal9 ft/s to only 6.2 ftls. Under these conditions, the 

S02 removal efficiency increased to 96.5 % compared with 92% in Test 2 with five pumps 

operating at the normal flue gas velocity. 

2-12 
2.4.2 Baseline Test CEM Traverse Data 

Figure 2-2 shows the results of the outlet duct traverses done with the portable 

S02 analyzer. The numbers inside the squares represent the measured S02 concentrations at the 

indicated positions in the duct. In this representation, the direction of flue gas flow is towards 

the reader. The numbers to the right of and below the squares are the average concentrations for 

the respective rows and columns. 

Three tests were done to examine the distribution of S02 across the outlet duct. 

The first two were done at approximately the same gas velocity in the scrubber ( 4 Modules on 

line) but with different numbers of recycle pumps operating (3 and 5). The third test was done 

with lower gas velocity obtained by bringing a fifth module on line. The results show that there 

is some variation in S02 concentration across the outlet duct and presumably across the module. 

A comparison of the first two tests shows that the number of operating pumps did not have a 

strong effect on the S02 distribution across the duct. The lowest readings remained in the same 

relative position. The highest readings shifted from the top of the duct in the three-pump test to 

the bottom of the duct in the five-pump test, but these differences were not large. 

The change in gas velocity had a more noticeable effect on S02 distribution across 

the duct. With the lower velocity, the lowest readings shifted to the top of the duct, and the 

average across the top of the duct was much lower than the average across the bottom of the duct. 

The averages down the right-hand side of the duct were also much lower than those down the 

left-hand side. Apparently, at low velocity, the inlet flue gas does not penetrate as well to the 

rear of the absorber module (across from the inlet). 

2.4.3 Sodium Formate Parametric Test 802 Removal Efficiency 

Table 2-2 summarizes the average test conditions and S02 removal efficiency 

results for the parametric tests with sodium formate additive. The format of this table is the same 

as Table 2-1, except that the measured concentrations of sodium formate (as formate ion) in the 

2-13 
TopofDuct 

275 I 265 I 205 I 235 245 

r- - - - - - -

272 I 230 I 159 I 215 219 

r- - -1 - - 1- - """'! 

Test3 255 I 160 I 98 I 160 168 

r- - - - - - - - 4 Modules, 3 Pumps, 220 I 136 I 43 I 170 142 andpH5.6 r- - -I 1- - -I 

210 I 194 I 170 I 185 190 r- - - - - -

217 I 226 I 220 I 216 220 

240 202 149 197 

TopofDuct 

312 ; 275 ; 170 ; 225 246 - - - - - - - 298 I 215 I 120 I 215 212 - -1- - 1- - """'! 

TestS 335 I 160 I 120 I 218 208 

4 Modules, 5 Pumps, - - - - - - -

andpH5.2 390 I 165 I 60 I 296 228 - -1- - 1- - -I 

325 I 255 I 315 I 300 299 - - - 365 I 325 I 365 I 360 354 

338 232 192 269 

Gas 

TopofDuct Inlet 

I I I 

34 13 I 0 I 8 14 r- - - - - - 41 I 11 I 0 9 15 

r- - -I - - 1- - """'! 

Test7A 61 17 0 9 22 

5 Modules, 5 Pumps, I I I 

r- - - - - - - - and pH5.8 71 I 50 I 8 I 22 38 

r- - -1- - 1- - -I 

50 I 60 I 40 I 29 45 

r- - - - - - - - 54 I 53 I 51 I 35 48 

' 

52 34 17 19 

Figure 2-2. Results of CEM Traverses at Module E Outlet (ppm S02 dry) 

2-14 
Table2-2 

Average Sodium Formate Parametric Test Conditions and Results 

2-15 
test module reaction tank are also shown. More detailed test data for the individual Method 6 

traverses are included in Appendix A, Table A-2. 

The parametric test series began with a two-day test at normal operating 

conditions (four modules on line, pH set point at 5.6, and four spray pumps operating per 

module) but with nominally 500 mg/L formate additive (750 mg/L as sodium formate) in the test 

module. For this test, the S02 removal efficiency averaged about 97%. 

Test 2, was also a two-day test. For this test, the pH set point and number of 

operating pumps remained at 5.6, and four pumps remained in operation. The formate additive 

concentration was increased to a nominal level of 1000 mg/L (1500 mg/L as sodium formate). 

Operation at Test 2 conditions with 1000 mg/L formate increased S02 removal to an average of 

98%. 

Tests 3 and 4 were conducted at the same nominal formate concentration ( 1000 

mg/L) and operating pH (5.6), but the number of operating pumps varied (five pumps for Test 3 

and three pumps for Test 4). In Test 3, with five pumps operating, S02 removal efficiency 

increased to 99%. In Test 4, with three pumps operating, S02 removal decreased to 96.6%. 

The pH set point was adjusted to 5.8 for Tests 5 (five pumps) and 6 (three pumps) 

at 1000 mg/L formate. At the higher pH set point, the S02 removal efficiency ranged from 

97.4% with three pumps operating to 99.3% with five operating. 

The pH set point was lowered to 5.2 for Tests 7 (three pumps) and 8 (five pumps) 

with the formate additive concentration remaining at the nominal 1000 mg/L level. At this lower 

pH set point, the S02 removal efficiency was 92.3% with three pumps and 96.5% with five 

pumps operating. 

Following Tests 7 and 8, the formate concentration in the test module reaction 

tank was increased to approximately 1500 mg/L for Test 9. The pH set point and number of 

2-16 
operating pumps were returned to normal levels (pH 5.6 and four pumps). The average S02 

removal efficiency was about 98.4% for this test. 

Test 10, the final parametric test, was conducted after the formate concentration in 

the test module reaction tank was increased to 3800 ppm. With the pH set point at 5.6 and four 

pumps operating, S02 removal increased to 99.4% 

2.4.4 S02 Removal Performance Correlations 

Absorber performance can be approximately described by the following 

expression derived from the "two-film" theory of mass transfer: 

where: 

Number of Transfer Units (NTU) = ln (S02ijS020u1

) = K* NG 

SOzin and S02out = inlet and outlet S02 concentrations; 

K (lblhr-ft2

) = average overall gas-phase, mass-transfer coefficient; 

A (ft2

) = total interfacial area for mass transfer; and 

G (lb/hr) =total gas flow rate. 

(2-1) 

It is assumed in the above expression that the equilibrium partial pressure of S02 above the FGD 

liquor is small compared with the inlet and outlet flue gas S02 concentrations. 

The overall coefficient K can be expressed as a function of two individual 

coefficients, kg and k1

, that represent mass-transfer rates across the gas and liquid films, 

respectively: 

(2-2) 

Where His a Henry's Law constant, and <I> is the liquid-film "enhancement factor" that includes 

the effects of changes in liquid alkalinity on the S02 mass-transfer rate. For a given absorber, 

2-17 
operating at constant gas and liquid flow rates, NTU will be a function of slurry pH because of 

the effect of pH on the enhancement factor and, hence, on the value of K. NTU will also be a 

function of additive concentration for the same reason. 

The form of Equation 2-2 suggests that the effects of increasing pH and additive 

concentration will diminish at some point when Hlk1

4> becomes small compared with 1/kg. This 

is referred to as "gas-film-limited" mass transfer. When this point is reached for a given 

absorber, there is no further benefit to increasing the additive concentration. 

Equation 2-1 shows that NTU should be inversely proportional to gas flow rate (if 

the product of K* A is independent of gas velocity) and proportional to liquid flow rate (if A is 

proportional to liquid flow rate). The S02 removal performance data from the baseline and 

parametric tests have been used to examine the actual effects of L, G, pH, and formate 

concentration on NTU. 

During the baseline and parametric tests, performance was measured at controlled 

levels of slurry pH, slurry flow rate (number of pumps), and formate concentration. In addition 

to these controlled variables, the inlet S02 concentration and flue gas velocity in the test module 

varied throughout the tests. The detailed test data from Tables A-1 and A-2 were analyzed using 

a non-linear least-squares curve fit routine to examine how these uncontrolled changes in test 

conditions affected S02 removal efficiency. This calculation showed that NTU varied with inlet 

S02 .o.zs, and G.o·3• 

The observed effect of gas velocity on NTU is less than predicted based on 

· Equation 2-1, unless the product K* A increases significantly with increasing gas velocity. In 

practice, for the spray tower absorber used in the Kintigh FGD system, an increase in flue gas 

velocity will increase the "A" term in Equation 2-1 because the velocity of small droplets through 

the absorber will decrease with increasing gas velocity and therefore increase their contribution 

to surface area. It is also possible that the increase in relative velocity between the flue gas and 

droplets increases K because of increased turbulence at the droplet surface. 

2-18 
Another way that flue gas velocity can affect performance is through its effect on 

flue gas distribution in the absorber. The CEM traverse data showed that gas distribution appears 

to improve with increasing gas velocity. This could also contribute to the apparent increase in 

K* A with increasing gas velocity. 

In order to examine the effects of the controlled variables, the NTU data from 

Tables A-1 and A-2 were adjusted to a constant gas velocity of 9 ftls and a constant inlet S02 

concentration of 1600 ppm using the observed dependence of NTU on these variables. Figure 

2-3 shows the effect of formate concentration on adjusted NTI1 for tests at pH 5.6 with three, 

four, and five pumps operating. As seen in previous tests with organic acid aClditives at other 

FGD systems, much of the relative increase in mass transfer is obtained over the range from 0 to 

1000 mg!L formate. 

Figure 2-3 also illustrates the relationship between NTU and recycle slurry spray 

rate. Comparing the three-pump and five-pump data, NTU is seen to be less than proportional to 

the slurry spray rate (L), which indicates that droplet surface area does not increase 

proportionately with increasing spray rate. At Kintigh, NTU was proportional to L0

·

65• Results 

from some of the other absorber types in this project showed that NTU was directly proportional 

to L. Apparently, droplet agglomeration or other effects in the Kintigh spray tower reduce the 

effectiveness of increasing slurry spray rate. 

Figure 2-4 shows the effect of slurry pH on NTU for tests with approximately 

1000 mg/L formate and three or five pumps operating. 

2.5 Results of Slurry Sample Chemical Analyses 

2.5.1 Solid-Phase Analyses 

Detailed results of solid-phase analyses for the baseline and parametric test slurry 

samples are included in Appendix A, Tables A-3 and A-4. These results were used to calculate 

2-19 
6 

5 

4 

2 

1 

0 

--.- 3 Pumps ~ 4 Pumps --..- 5 Pumps I 

S02 Removal 

-------------------------- --------------- ~% 

- --------------------------------------- 90% 

500 1000 1500 2000 2500 3000 3500 4000 

Formate Concentration (mg!L) 

Figure 2-3. Adjusted NTU vs. Formate Concentration for Tests 

at pH= 5.6 

2-20 
-~ 

.... 

= e 

"" Q 

~ 

,......, ~ ~ e 

= = Q 

N = 0 = 

~ 

~ N 0 

0 00 

l'7..l e - g. 

= 

g. 

-........ = = ~ \C 

~ 

E-1 

z ~ """' Cl\ 

Q 

.... 

"CS 

~ 

.... 

ell 

= :s 

< '-' 

5.0 

4.5 

4.0 

3.5 

"3.0 

2.5 

2.0 

5.0 

• 3 Pumps 0 5 Pumps I 

S02 Removal 

----------------------------------- ------ 99% 

oo 

0 

98% 

• 

---------------------- 95% 

• 

90% 

5.2 5.4 5.6 5.8 6.0 

Slurry pH 

Figure 2-4. Adjusted NTU vs. pH for Tests with 1000 ppm Formate 

2-21 
limestone utilization and sulfite oxidation, which are important process performance parameters. 

Results are briefly summarized here. 

Calculated limestone utilization values from Table A-3 for the baseline tests have 

been plotted as a function of slurry pH in Figure 2-5. This curve is typical of results seen at the 

other limestone FGD process test sites. At the low end of the operating pH range, utilization 

gradually decreases with increasing slurry pH. Then, at the high end of the operating pH range, 

where the liquor is nearly saturated with respect to calcium carbonate, utilization falls off very 

rapidly. In Figure 2-5, it can be seen that the results for Baseline Test 6 do not lie on the fitted 

curve because of a pH measurement problem during this test. 

Limestone utilization results from the sodium formate parametric tests are plotted 

versus slurry pH in Figure 2-6. Utilization results for the baseline tests from Figure 2-5 are also 

shown as a curve fit to those data. This comparison shows that limestone utilization data for the 

parametric tests are very scattered. Duplicate carbonate analyses showed very good analytical 

data quality. Therefore, the scatter in the data is most likely due to pH measurement or slurry 

sampling problems (see discussion in Appendix A). 

Calculated sulfite oxidation percentages from Table A-3 for the baseline tests 

averaged about 3.8%. There appears to be a slight decrease in oxidation percentage beginning 

with Baseline Test 6. However, only the solids from Test 1 would have been expected to reach a 

steady-state composition corresponding to conditions for that particular test. 

Sulfite oxidation percentages during the parametric tests averaged 4.7%, which is 

slightly higher than the 3.8% average for the baseline test solids. On the average, the unit load 

was significantly lower during the parametric tests, so a slight increase in oxidation (caused by 

higher excess air in the flue gas) is not surprising. There appears to have been a slight decrease 

in oxidation during Parametric Test 9 compared with earlier tests, but the decrease was small. 

There was also an increase in thiosulfate concentration in the recirculating liquor between Tests 8 

and 9 (see Liquid-Phase Analyses Table A-6), which could account for this change. 

2-22 
100 

95 

- 90 

~ '-" 

= 85 Q 

.... 

-

c= 

N .... 

.... 

-

- 80 I:J 

~ 

= Q 

- 75 l:ll 

~ 

5 

.... 

~ 

70 

65 

60 

4.8 5.0 

Om:J 

~ Test6 

pH Error 

5.2 5.4 5.6 

Slurry pH 

Figure 2-5. Baseline Test 

Limestone Utilization vs. Slurry pH 

2-23 

5.8 6.0 
95 

90 0 

-

~ .._, 85 

= Q 

·--;; 

N 

·-·--

- 80 ::;J 

~ 

s = 

!;1.:1 

5 75 

·-~ 

70 

65 

5.0 5.2 

0 

0 

0 0 ld 0 

' 0 0 

Baseline 0 Results 

0 

0 DOD 

0 

0 0 

0 

0 

5.4 5.6 5.8 

Slurry pH 

Figure 2-6. Parametric Tests 

Limestone Utilization vs. Slurry pH 

2-24 

0 

0 

0 

0 

6.0 
2.5.2 Liquid-Phase Analyses 

Detailed results of liquid-phase analyses for the baseline and parametric test 

filtered slurry samples are shown in Appendix A, Tables A-5 and A-6. Calculated relative 

saturations are also shown in the liquid-phase analytical results table. Relative saturation for a 

specific compound is defined as the activity product for the ionic components in solution divided 

by the solubility product. These values were obtained using Radian's Aqueous Chemical And 

~hysical ~roperties (ACAPP) computer routine, which calculates the equilibrium distribution of 

chemical species using the analytical results as inputs. 

Of greatest interest in an inhibited-oxidation FGD system such as this is the 

gypsum relative saturation. The objective of inhibiting oxidation with sulfur (which reacts to 

produce thiosulfate in solution) is to prevent scaling by maintaining the gypsum relative 

saturation below 1.0. Previous research has shown that all of the sulfate produced by oxidation 

of absorbed S02 will precipitate as a solid solution with calcium sulfite, up to the point where the 

system oxidation percentage reaches about 15%. Above 15% oxidation, the balance of the 

sulfate (beyond 15% of the S02 absorbed) will precipitate as gypsum. 

The results in Table A-5 show that the baseline liquor samples all had gypsum 

relative saturations well below 1.0. These results are consistent with the solids analyses, which 

showed that the baseline test oxidation percentage was well below 15%. The gypsum relative 

saturations decreased somewhat during and following Baseline Test 6, consistent with the solids 

analyses, which showed a corresponding decrease in sulfite oxidation percentage. Table A-6 for 

the parametric tests again shows that estimated gypsum saturations are well below 1.0, but they 

are slightly higher than for the baseline tests. This is consistent with solids analyses, which 

showed slightly higher sulfite oxidation percentages for the parametric tests. 

The parametric liquid analyses results can be compared with the baseline values to 

examine effects of the sodium formate additive on process chemistry. There does not seem to be 

any change in process chemistry that can be specifically related to the formate additive other than 

2-25 
the obvious increase in sodium concentration. There was about a 20% increase in dissolved 

magnesium and a 15% decrease in dissolved chloride between the baseline and parametric tests. 

The combined result of these changes in sodium, magnesium, and chloride concentrations was to 

lower the dissolved calcium concentration substantially in the parametric tests compared with the 

baseline tests. 

Concentrations of 32 elements were also determined in selected samples using 

inductively coupled plasma emissions spectroscopy (ICPES). These data are summarized in 

Table A-7. There were no remarkable differences in the results for the baseline and parametric 

tests. 

2.6 Sodium Formate Consumption Test Conditions and Results 

The parametric tests were followed by a steady-state sodium formate consumption 

test. The cost-effectiveness of using additives to enhance S02 removal depends both on the 

performance increase and the consumption rate of the additive. The objective of the 

consumption test was to measure the amount of sodium formate required to maintain high S02 

removal efficiency with the entire FGD system. Sodium formate was added continuously to the 

entire system for a period of six days, and the consumption rate was determined by material 

balance. 

2.6.1 Consumption Rate Calculation 

The consumption rate of sodium formate was determined by performing a liquidphase formate ion mass balance on the FGD system. This required monitoring sodium formate 

addition rate, formate losses with liquor adhering to the filter cake, and changes in liquid-phase 

formate inventory over the duration of the test. 

The sum of the following terms represents the total loss of sodium formate from 

the Kintigh FGD system during the consumption test: 

2-26 
1. Solution loss - formate lost in liquor adhering to the filter cake. Liquor 

blowdown from the FGD system would also contribute to the solution 

loss, but there was no separate liquor blowdown stream from this FGD 

system. 

2. Degradation - formate lost due to chemical or biological oxidation of 

formate to produce C02 and water. 

3. Coprecipitation loss- formate lost by incorporation into the calcium sulfite 

crystal structure. 

4. Vaporization- formate lost by vaporization (as formic acid) into the flue 

gas. 

The solution loss can be calculated for a given system based on the S02 removal 

rate, additive concentration, and filter cake moisture content. The sum of losses 2, 3, and 4 is 

normally termed the "nonsolution loss." The nonsolution loss is less easily predicted. The total 

nonsolution loss can be determined by subtracting the total solution loss from the total 

consumption, but the individual terms in the total nonsolution loss can only be estimated. 

Using the terms defined above, the following form of the system mass balance 

gives the average nonsolution loss rate for a given test period: 

Formate nonsolution loss (lb) = 

Formate added (lb) - Formate inventory change (lb) - Formate solution loss (lb) 

The formate addition term was obtained by measuring the change in the sodium formate tanker 

level. The solution loss term was obtained by multiplying the total filter cake production for a 

given test period by the average filter cake moisture content and filtrate formate concentration. 

The inventory change term was obtained by monitoring changes in formate concentration in all 

of the system vessels throughout the test. Details of the formate consumption test material 

balance are included in Appendix B. 

2-27 
The additive nonsolution loss rate is normally reported on an S02 removal basis 

(lb of formate or sodium formate per ton of S02 removed). S02 removal in the FGD system for a 

given test period was calculated using hourly averages for unit load, an assumed gross heat rate, 

and inlet and outlet S02 concentrations (in lb S02 per million Btu heat input) measured by the 

certified inlet and stack continuous emissions monitors (CEMs). As a check on this estimate, 

S02 removal was also estimated from the amount of limestone used by the FGD system. 

2.6.2 Results 

Sodium Formate Consumption 

Table 2-3 is a summary of the liquid-phase formate material balance for the 

duration of the consumption test from 917/94 to 9112/94. In this calculation, total formate 

consumption is divided into "solution losses," which includes formate leaving the system with 

the filter cake moisture; and "nonsolution losses," which includes all other loss mechanisms such 

as vaporization, degradation, and precipitation. 

During the 120-hour test duration between the initial and final formate 

inventories, a total of 13,380 lbs of formate (20,220 lbs of sodium formate) was added to the 

system. The average feed rate was 168lblhr as sodium formate. The total system liquid-phase 

formate inventory decreased by 1,420 lbs out of a total of about 40,000 lbs. The total formate 

consumption for the test (the addition term plus the inventory decrease) was 14,800 lbs. A total 

of 1,700 lbs or 11% of the total formate consumption was accounted for by formate lost from the 

system in the liquor adhered to the filter cake solids. This 11% of the total formate consumption 

represents the solution losses. The remaining consumption (13,100 lbs of formate) represents the 

sum of the nonsolution losses. 

During the test, a total of 1,346 tons of S02 were removed from the flue gas by the 

FGD system. The S02 removal efficiency averaged about 97% during periods when the bypass 

damper was closed. The average formate concentration in the module reaction tanks was about 

2-28 
Table 2-3 

Summary of Sodium Formate Consumption Test Results a 

Total added (lbs) 13,380 

Total liquid-phase inventory change (lbs) -1,420 

Total consumption (lbs) 14,800 

Total loss with filter cake liquid (lbs) 1,700 

Total non-solution loss (lbs) 13,100 

Total S02 removed (tons) b 1,346 

Total solution loss rate (lb/ton SOz) 1.3 

Total non-solution loss rate (lb/ton S02) 9.7 

Total consumption rate (lb/ton S02) 11.0 

Average feed rate (lblhr) 111 

Initial average module concentration (mg/L) 1,045 

Final average module concentration (mg/L) 1,120 

97 

a Results calculated between the 917 and 9/12 inventories. 

b S02 removal based on the CEM data and boiler load. 

2-29 

20,220 

-2,150 

22,360 

2,570 

19,790 

1,346 

2.0 

14.7 

16.6 

168 

1,580 

1,690 

97 
1080 mg/L. Expressed on an S02 removal basis, the total additive consumption rate was 11 

lb/ton so2 as formate or 16.6 lb/ton so2 as sodium formate. The solution and nonsolution loss 

rates were 1.3 and 9.7lb/ton S02, respectively, on a formate basis and 2.0 and 14.7lb/ton on a 

sodium formate basis. 

An error propagation analysis was done to estimate the uncertainty in the formate 

consumption results using the procedure outlined in ANSI/ASME Power Test Code 19.1-1985, 

"Measurement Uncertainty." The uncertainty analysis indicated that the total calculated sodium 

formate consumption (16.6lb sodium formate/ton S02 removed) is accurate to about ±3.5lb/ton 

or ±21% at the 95% confidence level. The nonsolution loss term (14.7lb sodium formate/ton 

S02 removed) is accurate to ±3.6lb/ton or ±25%. 

Relative Importance of Different Loss Mechanisms 

The above sodium formate consumption measurement was based on the liquidphase material balance. The results of filter cake solids analyses from the consumption test and 

flue gas analyses from the parametric tests can also be used to estimate the relative contrib1,1tions 

of precipitation, vaporization, and degradation to the total nonsolution loss. 

Analyses of daily filter cake samples obtained during the consumption test 

showed an average solid-phase formate concentration of 0.8 mg/g of dry solids, or 0.08 weight 

percent. The theoretical rate of filter cake solids production is about 2.2 tons dry filter cake/ton 

of S02 removed (at 90% limestone utilization, 3% oxidation, neglecting fly ash and other inerts). 

Using these data, the average loss rate of formate with the solids would be 3.5 lb formate/ton of 

S02 removed (5.3lb/ton as sodium formate), which accounts for about 36% of the total 

nonsolution loss rate. 

The flue gas was also analyzed for formic acid during several of the formate 

parametric tests. In many cases, the formic acid concentrations were less than the estimated 0.1 

to 0.2 ppm detection limit for the sample. The maximum flue gas formic acid concentration 

2-30 
measured was about 1 ppmv during Parametric Test 1. At full load, the flue gas flow rate at 

Kintigh is about 1,700,000 scfm, and the S02 removal rate averages about 11 ton/hr. A flue gas 

formic acid concentration of 1 ppmv corresponds to a vaporization loss rate of about 1 lb formic 

acid/ton of S02 removed. This loss rate accounts for a maximum of about 10% of the total 

nonsolution loss rate. The actual formate vaporization loss rate may have been much less than 

10% of the nonsolution loss rate. 

The formate degradation rate cannot be measured directly. However, based on 

measurement of the total nonsolution loss rate and estimates for two of the three 

nonsolution loss mechanisms, by difference, the degradation loss rate accounts for about 55 to 

65% of the total nonsolution loss rate. 

Results of Consumption Test Slurry Analyses 

Tables B-2 and B-3, Appendix B, summarize the results of solid-phase and liquidphase analyses for slurry samples obtained during the consumption test. The solid-phase results 

show that the FGD system continued to operate at very low oxidation percentages: an average of 

about 2.5% for the long-term test samples, compared with 3.8% for the baseline tests and 4.7% 

for the parametric tests. 

The average system load for the long-term tests was similar to that for the baseline 

tests, but the thiosulfate concentration in the liquid (see Table B-3) averaged 750 mg/L during the 

long-term test compared with 240 mg/L for the baseline tests and 320 mg/L for the parametric 

tests. Therefore, the lower oxidation percentages seen during the long-term test may be a result 

of higher thiosulfate concentration. An oxidation-inhibiting effect of sodium formate additive 

was seen at another site in this project (SWEPCo's Pirkey FGD system), but the oxidation data 

from Kintigh are too confounded by unit load and thiosulfate concentration to determine if there 

was a similar effect. 

2-31 
Limestone utilization results from Table B-2 have been plotted for comparison 

with the baseline test results in Figure 2-7. These results did not exhibit the wide scatter that was 

seen during the parametric tests. The comparison in the figure indicates that the sodium formate 

additive had no significant effect on limestone utilization. 

Referring to Table B-3, the liquid analyses for the long-term tests show trends that 

are consistent with the solids analyses. The lower oxidation during the long-term tests resulted in 

lower liquid-phase sulfate concentrations and lower gypsum relative saturations compared with 

the baseline and parametric tests. 

2.7 Effect of Sodium Formate Additive on Solids Dewatering Properties 

Tests were performed to examine the effect of sodium formate on other solids 

properties. If sodium formate is used as a performance-enhancing additive, changes in solids 

properties caused directly or indirectly by this additive could affect the operation of dewatering 

equipment. 

Three methods were used to examine solids samples from Module E as part of 

this test program: settling tests, filter leaf tests, and scanning electron microscopy (SEM). 

Settling tests were performed on site using lower-loop slurry samples to ascertain the effect of 

sodium formate on sedimentation properties. The bulk settling procedure detailed in Method C2 

of EPRI' s FGD Chemistry and Analytical Methods Handbook was followed (rake action was not 

simulated). Filter leaf tests, as described in Method C3 of EPRrs Handbook, were performed to 

assess changes in the solids filtration rate and solids water retention under vacuum filtration. 

Finally, SEM was used qualitatively to examine changes in crystal structure. 

2. 7.1 Settling Test Results 

Batch settling tests were performed on slurry samples from the Module E primary 

reaction tank from which slurry is bled to the dewatering system. These tests determine both 

2-32 
100 

95 

D 

,-... 90 

..._, 

~ 

= Q 85 ·-.... 

~ 

N 

·--·-.... 

p 80 

~ 

= .s 75 riJ 

5 .... 

~ 

70 

65 

60 

4.8 

• 

0 • • 

0 0 euan 

D 0 • 

~ ~ 

D 

• 

D Baseline Tests 

• Long-Term Test 

5.0 5.2 5.4 5.6 5.8 

Slurry pH 

Figure 2-7. Comparison of Baseline and Long-Term Tests 

Limestone Utilization 

2-33 

6.0 
settling rates and final solids underflow concentrations. Settling rates are reported as the 

thickener unit area (UA, ft2/ton/day) required to reach a 30 wt.% underflow concentration. 

Lower unit areas correspond to slurries that settled faster. 

Settling test results are summarized in Table 2-4. Four settling tests were done 

during Baseline Test 1. The average calculated unit area of about 2 ft2

/ton/day indicates a 

relatively fast-settling sulfite sludge, characteristic of inhibited-oxidation limestone FGD systems 

with very low oxidation percentages. 

A total of eleven settling tests were done during the parametric tests: three during 

each of the two-day tests (Tests 1, 2, and 9) at increasing formate concentrations, and two extra 

tests with 1000 ppm formate in the test module. Three additional settling tests were done during 

the consumption test. The parametric and consumption test results are also summarized in Table 

2-4 along with the baseline results. Also, shown in the table are average unit loads for a 48-hour 

period prior to each of the settling tests. 

The first settling tests for the parametric test series were done during Test 1, after 

500 ppm formate had been added to the test module. The results of these tests showed higher 

unit areas compared with the baseline results. The settling rate decreased markedly over the next 

few days, and the unit area increased to an average of 17 ft2

/ton/day during Parametric Test 2 

with 1000 ppm formate in the test module reaction tank. Over the same time period, however, 

the unit was operated at a much lower load than usual, so that the observed increase in unit area 

may have been a result of increased oxidation percentages due to higher excess air in the flue gas. 

The unit returned to sustained high-load operation over the weekend prior to Test 9, and the 

settling rate increased (unit area decreased) to levels less than that of Parametric Test 1 and 

approaching that of the baseline tests. Therefore, it is unlikely that formate alone affected the 

settling rate to any great extent. 

2-34 
B-1 Baseline 

pH5.6 

P-1 500mg/L 

formate 

pH5.6 

P-2 1000mg/L 

formate 

pH5.6 

Extra 1000mg/L 

formate, pH 5.8 

Extra 1000mg!L 

formate, pH 5.6 

P-9 1500mg!L 

formate 

pH5.6 

C-1 1040mg!L 

formate, pH 5.6 

C-2 1180mg/L 

formate, pH 5.6 

1250mg!L 

C-3 5.6 

7/18/94 

7119/94 

7119/94 

7/19/94 

8/22194 

8/23/94 

8/23/94 

8/25/94 

8/25/94 

8/25/94 

8/26/94 

8/27/94 

8/29/94 

8/29/94 

8/29/94 

9nt94 

9/9/94 

9/12/94 

Table 2-4 

Results of Settling Tests 

1530 NA 

0800 NA 

1340 564 

1435 573 

1200 651 

1200 600 

1310 598 

0820 410 

1310 412 

1610 424 

1330 533 

0900 632 

0730 638 

1125 631 

1620 624 

1405 NA 

1325 664b 

1140 647 

a Initial slurry solids content estimated from NYSEG slurry density data. 

b Thirty-hour average load prior to test. 

NA = Data not yet available. 

2-35 

9.0 1.9 65 

9.7 2.3 60 

11.2 1.9 61 

10.6 2.2 64 

10.9 2.9 54 

9.3 4.4 51 

9.3 4.8 49 

7.8 18 39 

7.8 20 38 

10.4 12 40 

10.4 11 43 

10.9 11 43 

9.0 3.9 52 

8.9 3.3 49 

9.0 2.7 55 

7.0 2.9 46 

11.3 1.9 56 

10.1 2.0 50 
Settling tests done during the consumption test yielded estimated unit areas about 

the same as for the baseline results. The unit was operated at sustained high load throughout the 

consumption test. This confirmed that sodium formate had little effect on slurry settling rate. 

2.7.2 Filter Leaf Tests 

The results of the filter leaf tests are summarized in Table 2-5. The results include 

"form filtration rate (lblhr-ft2

)," which is an indicator of the potential vacuum filter throughput 

per unit filter cloth area, and the final filter cake moisture contents under standard drying 

conditions. fu Table 2-5, the test designation "B-1" refers to Baseline Test 1, and the designation 

"P-1" refers to Parametric Test 1. 

The form filtration rates show a trend that follows the settling test results. That is, 

the filtration rates for the baseline and initial parametric test are similar, but the filtration rate 

decreased substantially during the second parametric test. By the end of the parametric tests, 

h0wever, the filtration rate was at least as high and possibly higher than the initial rate for the 

baseline tests. Again, this trend is most likely related to the unit load and sulfite oxidation 

percentage rather than to the sodium formate additive. 

2.7 .3 Scanning Electron Microscope (SEM) Photographs 

Figures 2-8a and b through 2-11 a and b are SEM photographs of slurry solids 

samples from the two-day baseline test (Baseline Test 1) and from the three two-day parametric 

tests at increasing formate levels (Parametric Tests 1, 2, and 9). These photos reveal no 

significant changes in crystal habit with sodium formate additive. 

2-36 
Table 2-5 

Results of Filter Leaf Tests 

B-1 7119/94 1045 520 69 

B-1 7119/94 1345 530 70 

B-1 7119/94 1520 450 71 

P-1 8/23/94 1200 530 72 

P-1 8/23/94 1500 550 71 

P-1 8/23/94 1806 560 69 

P-2 8/25/94 0815 270 70 

P-2 8/25/94 1300 235 69 

P-2 8/25/94 1626 210 72 

P-9 8/29/94 0800 520 68 

P-9 8/29/94 1124 530 70 

2-37 
Figure 2-Sa. Solids from Baseline Test 1 (500x) 

Figure 2-8_1>. Solids from Baseline Test l (1000x) 

2-38 
Figure 2-9a. Solids from Parametric Test 1 (500x) 

Figure 2-9a. Solids from Parametric Test 1 (lOOOx) 

2-39 
Figure 2-lOa. Solids from Parametric Test 2 (500x) 

Figure 2-lOb. Solids from Parametric Test 2 (lOOOx) 

2-40 
Figure 2-lla. Solids from Parametric Test 9 (500x) 

Figure 2~11b. Solids from parametric Test 9 (lOOOx) 

2-41 
2.8 Other Process Data 

2.8.1 Control Room Data 

Process data were recorded during the baseline, parametric, and formate 

consumption tests by the plant data acquisition system and from control-room indicators. These 

data are summarized in Appendix C, Tables C-1 and C-2. 

2.8.2 Recycle Pump Slurry Flow Rate Measurements 

Recycle pump slurry flow rates were measured using an ultrasonic Doppler-effect 

flow meter. Each pump was tested several times during the baseline and parametric tests. Pump 

motor current and discharge pressures were also recorded. Results are summarized in Table 2-6. 

The flow measurements were reproducible, and the recorded flows agreed well with those 

expected based on the 10,900 gpm nominal capacity rating for these pumps. 

2.8.3 S02 Removal Data for the Consumption Test 

Overall FGD system S02 removal efficiencies measured during the consumption 

test are summarized in Table 2-7. In order to measure overall S02 removal efficiency during the 

consumption test, it was necessary to close the system bypass damper so that the system 

efficiency could be measured using the inlet and stack CEM data. The normal operating 

procedure at Kintigh includes sufficient flue gas bypass to maintain an outlet flue gas 

temperature of about 131 °F so that excess condensation does not occur in the scrubber outlet 

plenum. The data in Table 2-7 represent average removal efficiencies for one-hour periods each 

day during which the bypass damper was closed. With the bypass damper closed, the average 

S02 removal was nearly 97% with the unit operating at essentially full load. The average 

reaction tank formate concentration was about 1130 mg/L during periods when the bypass 

damper was closed. The S02 removal efficiency during the long-term test was slightly lower 

than the 98% level expected based on the parametric tests with a single module. However, 

2-42 
Table2-6 

Results of Recycle Pump Flow Measurements 

1 9850 9700 9650 9700 10000 9500 9700 45 NA 

2 10600 10500 10600 10500 10500 10500 10500 42 36 

3 11650 12000 11300 11400 10950 10950 11400 44 34 

4 10500 10000 9800 9750 10000 44 38 

5 10250 10200 10400 10350 10250 10300 42 37 

2-43 
Table 2-7 

802 Removal Efficiency During Consumption Test 

9/8/94 1100 675 1100 0.14 96.7 

9/9/94 1500 693 1120 2.88a {}.08 97.2 

9110/94 1000 673 1190 4.35 0.15 96.6 

9/11/94 1100 668 1110 4.51 0.17 96.2 

677 1130 96.7 

a Inlet S02 estimated due to CEM malfunction. 

2-44 
performance differences among the modules or leakage of a small amount of inlet flue gas 

through the bypass damper could easily account for the overall FGD system S02 removal 

efficiency being slightly lower than the measured Module E efficiency. 

2-45 

3.0 FGDPRISM MODELING RESULTS 

The FGD PRocess Integration and S,imulation Model (FGDPRISM) is a computer 

program that simulates the performance of wet lime and limestone FGD systems. The model 

was calibrated to NYSEG's Kintigh Station with data collected during two of the baseline and 

one of the parametric tests. Mter calibration, the model was used to predict performance for the 

remaining tests and to investigate some additional options that were not tested. The performance 

of a finer limestone grind was predicted, and the option of operating the unit at current S02 

removal levels with formate additive and fewer recycle pumps in service was evaluated. The 

results of the model calibration and the process simulations are summarized below. Detailed 

results are included in Appendix D. 

3.1 FGDPRISM Calibration Results 

The FGDPRISM model is calibrated to test results by adjusting several 

parameters. The parameters are adjusted to achieve the best fit with respect to liquid-phase 

chemistry, limestone utilization, and S02 removal efficiency for the cases used in the calibration. 

For the Kintigh FGD system, the main parameters of the calibration are: 

• Limestone reactivity; 

• Gas- and liquid-film thicknesses for the spray droplets; and 

• Calcium sulfite/sulfate solid solution precipitation rate. 

The limestone reactivity is adjusted by changing a variable called the surface area 

factor and the limestone reaction rate constant (k) to match the observed limestone utilization and 

pH in the reaction tank. The gas-film and liquid-film thicknesses are adjusted to match the masstransfer characteristics of the absorber. The calcium sulfite/sulfate solid solution precipitation 

rate constant is adjusted to match predicted and measured relative saturation values for solid 

calcium sulfite and sulfate compounds. 

3-1 
In addition to these primary calibration parameters, several other input values are 

adjusted to match the liquid chemistry present in the absorber. For example, the HCl content of 

the flue gas is varied to match the chloride concentration in the slurry and the limestone MgC03 

solubility and makeup water sodium and magnesium contents are varied to match the magnesium 

and sodium concentrations in the slurry. 

Figure 3-1 compares predicted versus actual S02 removal efficiency for the 

calibrated FGDPRISM model. 

3.2 Predictive Simulations 

The calibrated model was used to make several predictive simulations to evaluate 

some conditions that were not actually tested. First, the model was used to evaluate the effect of 

limestone grind on S02 removal efficiency. 

A screen size analysis of the limestone reagent used at Kintigh showed that the 

current grind is relatively coarse; 52% < 200 mesh, and 42% < 400 mesh. By comparison, the 

"standard" grind used at EPRrs Environmental Control Technology Center (ECTC) is about 93% 

< 200 mesh and 85% < 400 mesh. (Note that although the ECTC is located at the Kintigh 

station, the pilot- and full-scale FGD systems have independent limestone supplies and each has 

its own limestone grinding equipment.) 

Experience has shown that limestone grind can have a significant effect on S02 

removal efficiency at constant limestone utilization. The calibrated FGDPRISM model was used 

to predict performance for the Kintigh FGD system using the ECTC limestone grind instead of 

the measured grind. Under those conditions, FGDPRISM predicted that S02 removal efficiency 

at Kintigh could be increased to nearly 97% with four pumps operating. The predicted limestone 

utilization was 84%, a slight decrease from the baseline level of 85%, at an operating pH of about 

5.8. 

3-2 
100 

0 Baseline 

• Parametric Cil 

90 

0 

-'$. 

---

= 

~ 80 

a 

~ 0 ~ 

0 

V1 

"0 

~ 70 -

~ .... 

"0 

~ 

~ -

60 

so~~~~~._._._~~~~~~~~~~~~~~~~~~ 

50 60 70 80 90 100 

Observed so2 Removal (0/o) 

Figure 3-1. Kintigh FGDPRISM Calibration: 

Predicted vs. Observed Removal 

3-3 
The model was also used to predict limestone utilization for operation at the 

current S02 removal level with a finer grind. Using the ECTC grind as input, FGDPRISM 

predicted that the current S02 removal efficiency could be maintained with limestone utilization 

increasing from the baseline 85% to about 98%. 

The calibrated model was also used to evaluate the option of maintaining current 

so2 removal efficiency (with partial bypass) using sodium formate additive to permit operation 

with fewer spray pumps. With three spray pumps per module, the model predicted that only 125 

mg/L formate would be -needed to maintain current S02 removal (88% removal in the modules, 

85% overall removal including partial bypass). With two spray pumps per module, 670 mg!L 

formate would be needed. The cost effectiveness of these modeled conditions is discussed in the 

next section. 

3-4 
4.0 ECONOMIC EVALUATION 

Performance data from the baseline, parametric, and long-term sodium formate 

consumption tests were used to evaluate the economics of upgrades to increase S02 removal 

efficiency with the current Kintigh FGD system configuration. Some additional operating cases 

that were not tested were evaluated based on performance predicted by the calibrated 

FGDPRISM model. Results of these economic evaluations are presented in this section. 

4.1 Upgrade Options and Cost Basis 

Options to upgrade the so2 removal performance at Kintigh include operating 

without flue gas bypass at otherwise current conditions and/or adding sodium formate to the 

system. A number of upgrade cases were considered involving each of these options separately 

and in combination. For the options that included sodium formate addition, cases were 

considered with either three or four recycle pumps per modules in service and with a range of pH 

set points and formate concentrations. Table 4-1 summarizes the system design basis, cost 

components, and other assumptions necessary for evaluating these options. 

The maximum gross output of the Kintigh Station is about 700 MW. Based on 

1985 to 1993 data, an average of 1,794,000 tons per year of coal with a sulfur content of 2.33% 

were burned at Kintigh. The average heating value of the coal was about 13000 Btu/lb. The 

average reported capacity factor was about 85%. For the economic evaluation, this capacity 

factor was approximated by assuming that the unit operates 8000 hours per year with an average 

load of 660 MW. The average flue gas flow rate at 660 MW was estimated by combustion 

calculation to be 7.3 million lb/hr. 

The average equivalent S02 content of the fuel was 3.58 lb/million Btu, and the 

system outlet S02 was typically maintained at 0.52lb/million Btu. Based on these 1985 to 1993 

average data, the baseline annual amount of S02 removed is about 71,000 tons, and the baseline 

4-1 
Table 4-1 

Economic Basis for Kintigh S02 Removal Upgrade Options 

Maximum Continuous Rating 708MWgross 

Capacity Factor 86% (8000 hours at 660 MW avg.) 

Average Flue Gas Flow 7.3 million lblhr 

Average Fuel Sulfur Content 3.58 lb/million Btu 

Average Fuel Heating_ Value 12990 Btullb 

Current Average Outlet S0_2 0.52 lb/million Btu 

Current SO, Removal 71,000 tons/yr 

Additional S02 Available for Removal 12,500 tons/yr_ 

Capital Cost of Sodium Formate System $300,000 for 100 lblhr 

Annualization Factor 0.17 

Delivered Cost of Sodium Formate $0.24/lb, $0.30/lb 

Cost of Power $0.017/k.Whr 

Sodium Formate Consumption Rate 16.6lb/ton so2 at 1130 mg!L 

Cost of Prepared Limestone $12.50/ton 

Cost of Additional Sludge Disposal $7.50/ton 

fucrease in System AP to Treat all Flue Gas 0.6 in. H20 

Decrease/fucrease in System AP per Spray Pump 0.2 in. H20 

Fan Efficienc;y_ 80% 

A vera.ge Recycle Pump Power Consumption 280kW 

Current A verag_e Limestone Utilization 85% 

4-2 
emissions are about 12,500 tons/year. These baseline emissions represent the additional amount 

of S02 available for removal by operating the FGD system at higher efficiency. 

The capital cost of a sodium formate additive system sized for 100 lblhr was 

previously estimated to be about $300,000. This cost was adjusted as a function of capacity ratio 

using an exponent of0.15. An annual capital recovery factor of 0.17 was used. The delivered 

cost of sodium formate supplied by Perstorp during the test program was $0.24/lb. A cost of 

$0.30/lb was also used in the evaluation to look at the sensitivity of the results to the additive 

price. The results of the sodium formate consumption test indicated that the total consumption 

with 1080 mg!L formate in the reaction tanks was 16.6lb/ton of S02 removed. Based on results 

from pilot-scale tests at EPRI's ECTC, sodium formate consumption should be directly 

proportional to concentration. A linear relationship between sodium formate concentration and 

consumption was, therefore, assumed for the economic evaluation. 

Increases in system S02 removal will increase several operating costs, including 

limestone purchase and waste disposal costs. These costs were derived from data provided by 

NYSEG. Additional limestone reagent (prepared) was valued at $12.5/ton. The cost of 

dewatering and disposing of additional filter cake was estimated to be $7 .5/ton. 

Operation without flue gas bypass will increase FGD system pressure drop and fan 

power consumption. The average increase in overall system pressure drop due to treating all of 

the flue gas was estimated to be 0.6 in. H20 based on data obtained during the consumption test. 

Operation with fewer recycle pumps will decrease system pressure drop. A decrease of 0.2 in. 

H20 per spray pump taken out of service (in all operating modules) was estimated based on data 

obtained during the baseline and parametric tests. A fan efficiency of 80% was assumed, and the 

fan power was valued at $0.017/kWhr. 

The limestone utilization at the normal pH set point was observed during baseline 

testing to be about 85%. Utilization values for other pH set points were estimated from the 

baseline data (Figure 2-5). 

4-3 
4.2 Results 

The economic factors described above were included in a spreadsheet calculation 

that estimates the cost of additional tons of S02 removed for various operating conditions and 

levels of removal efficiency. Table 4-2 summarizes the results of these calculations for the most 

cost-effective options. Additional details of the calculation and results for some other options are 

shown in Appendix E, Table E-1. The cost of additional S02 removal was evaluated over a 

range of formate concentrations in each case to determine the optimum concentration. Only the 

optimum results are shown in the table. For higher formate concentrations than those shown in 

the table, the marginal cost of additional tons of S02 removed became greater than the assumed 

value of allowances. 

The first row of entries in Table 4-2 is based on current operational practice. The 

FGD system is operated with four modules and four pumps per module at a nominal pH set point 

of 5.6, and with 85% limestone utilization. The overall system S02 removal is about 85% with 

partial bypass being used to control condensation in the absorber outlet plenum. 

The first upgrade option in Table 4-2 is based on the option of closing the system 

bypass dampers, while maintaining FGD system operation at the current baseline conditions (pH 

5.6, four pumps per module). Based on the temperatures of the inlet flue gas, scrubber module 

outlet flue gas, and the stack gas, the typical amount of flue gas bypass was estimated to be 3%. 

The individual module efficiency was assumed to be unchanged with the small additional gas 

flow. Closing the bypass damper increases the S02 removal efficiency from 85 to 88%, 

removing an additional 2,500 tons/yr of S02• 

The costs associated with this option include fan power for increased pressure 

drop across the system with the bypass closed, as well as reagent, limestone, and sludge disposal 

costs for the additional S02 removed. The total cost increase is $128,000/yr, which results in an 

average cost of $51/ton of additional S02 removed by closing the bypass damper. 

4-4 
Table4-2 

Economic Comparison of S02 Removal Upgrade Options 

51 500 250 

53 1940 960 

97.8 85 10,640 810,000 76 1850 790 

Maintain 94.8 85 8,140 672,000 83 1360 550 

bypass add 

lOOOmgiL 

formate 

Maintain 85 85 0 (98,000) NA NA NA 

current S02 

removal with 

2Pumps and 

670mg/L 

formate 

Maintain 85 98 0 (224,000) NA NA NA 

currentS02 

removal with 

4pumps and 

finer 

limestone 

grind 

* Includes 3% partial bypass. 
Note that NYSEG chooses to operate with this small amount of gas bypass as a 

means of keeping the absorber outlet plenum dry. Operating with no bypass would result in wet 

conditions in the plenum. This wet operation would bring an associated potential for increased 

corrosion in the plenum and for "rainout" of acidic droplets from the stack. Capital upgrades 

such as adding more corrosion resistant materials of construction in the outlet plenum and adding 

droplet weirs in the stack could be implemented to decrease the potential for these problems. 

However, such upgrade costs were not estimated and were not evaluated in determining the cost 

effectiveness of closing the bypass. 

Instead, several upgrade options have been evaluated with and without gas bypass. 

The difference between the projected value of S02 credits generated with and without gas bypass 

represents the approximate annual amount that would be available to invest in capital upgrades to 

improve operation with the bypass closed .. 

For example, for this first option which includes no FGD system upgrades beyond 

closing the bypass damper, the additional S02 allowances removed would have an annual value 

of $250,000 if allowances are valued at $150/ton. If instead they are valued at $250/ton, the 

additional allowances would have an annual value of about $500,000. In the first instance, where 

the S02 allowances have a value of $150/ton, then capital upgrades amounting to up to $250,000 

annually may be cost effective if they would allow continuous closed bypass operation. 

The next option in the table is to use a finer limestone grind (93% < 200 mesh) at 

the same pH set point, also with the bypass closed and with the four-module, four-pump 

configuration. Under these conditions, FGDPRISM predicts that S02 removal efficiency should 

increase to 96.8%. With this substantial increase in removal efficiency, 9,840 additional tons of 

S02 are removed per year. The costs include additional fan power, reagent and waste disposal 

costs, plus an assumed cost differential ($1 00,000/yr) for operating the reagent preparation 

equipment at half of the current feed rate and for twice the current operating time to produce the 

finer limestone grind. The total cost of increased S02 removal using a finer limestone grind is 

4-6 

---------
$521,000/yr or $53/ton for the additional S02 removal. The net annual value of this option 

ranges from $960,000 to $1.94 million, depending on the assumed value of allowances. 

The next option in Table 4-2 is to close the bypass and add 1000 mg/L formate to 

the FGD system, while maintaining the current baseline pH set point (5.6) with four recycle 

pumps per module operating and with the current limestone grind. With these conditions, S02 

removal efficiency should increase to 97.8%. This corresponds to 10,640 tons/yr of additional 

S02 removed. Additional costs include fan power, reagent and waste disposal, plus the 

annualized capital cost of the additive storage system and the purchase cost of the sodium 

formate additive. The total annual cost for this option is $810,000, or an average of $76/ton of 

additional S02 removed. The annual value of additional S02 removed is about $1.85 million if 

allowances are valued at $250/ton and $790,000 if allowances are valued at $150/ton. 

As discussed previously, it is likely that NYSEG will not want to operate without 

partial bypass unless capital improvements are made. The next case evaluates the option of 

maintaining partial bypass, while adding formate to increase S02 removal. This option was most 

cost-effective with four recycle pumps per module and 1000 mg!L formate. The overall system 

S02 removal is 94.8% for this case, and the total annual value is $1.36 million (or $550,000 for 

$150 allowances). A comparison of the formate cases with and without partial bypass shows that 

closing the partial bypass can generate an extra $240,000 to $490,000/yr in allowance value. 

This is a significant potential revenue which might justify some capital improvements to permit 

operation without bypass. 

The final two cases in Table 4-2 evaluate operation at the current S02 removal 

efficiency with partial bypass. In the first of these, sodium formate is added to maintain so2 

removal with fewer recycle pumps. The required sodium formate concentrations ( 670 mg!L with 

two pumps per module) was predicted using FGDPRISM. The result shows that the fan and 

pump power savings exceed the cost of formate additive by nearly $100,000/yr. 

4-7 
In the final option in Table 4-2, the current S02 removal efficiency (with partial 

bypass) is maintained with four pumps per module using a finer limestone grind to increase 

limestone utilization. For this case, FGDPRISM predicted that limestone utilization could be 

increased to 98% at an operating pH of 5.5. The net annual savings for this case exceeds 

$200,000 even after allowing $100,000 for increased reagent preparation labor, power, and 

maintenance costs. 

4.2.1 Effect of Sodium Formate Additive Price on Results 

Additional economic cases were run to evaluate the effect of increased additive 

cost on the upgrade options. Increasing the cost of sodium formate by 25% to $.30/lb did not 

change the relative rankings of the additive options. The optimum formate concentration for the 

normal-pH, four pumps per module case remained at 1000 mg/L with sodium formate at 

$0.30/lb, butthe net annual value of this option decreased by about $70,000. 

4.3 Recommended Upgrade Option 

Based on the results of the economic analysis and the available test data, the use of 

sodium formate additive at a level of 1000 mg!L with four recycle pumps per module and the 

bypass closed appears to be the best upgrade option. This would result in greater than 97% S02 

removal, and remove an additional 10,000 tons of S02 per year. Under these conditions, the 

10,000 additional tons/yr of S02 will be removed at an average cost of about $76/ton. 

However, FGDPRISM predicts that use of a finer limestone grind might be a good 

approach, provided that the existing reagent preparation equipment can be adapted to produce the 

93% < 200 mesh fineness assumed for these predictions. More full-scale testing would be 

required to fully evaluate this option. This is particularly true because the reagent utilization 

predictions using FGDPRISM are typically not as accurate as the S02 removal predictions. 

4-8 
The economic analysis also showed that sodium formate additive should be costeffective for maintaining current S02 removal efficiency by allowing operation with fewer 

recycle pumps. 

4-9 

APPENDIX A 

Detailed S02 Removal Data and Chemical Analyses Results for 

Baseline and Parametric Tests 

A-1 

Tables A-1 and A-2 summarize the detailed test conditions and S02 removal 

efficiency results for the baseline and parametric tests, respectively. In these tables, each "test" 

represents a period of operation at constant conditions, and each "run" represents an individual 

Method 6 traverse at the absorber outlet. The times were recorded at the beginning and end of 

each traverse. The "average slurry pH" is measured with a calibrated portable meter. A reading 

was taken at the beginning and end of each traverse, and the average result is shown. In most 

cases (except Baseline Test 6), the portable meter agreed closely with the control room indicator. 

The "absorber flue gas velocity" was calculated from the outlet duct pitot traverse, adjusted to the 

scrubber cross sectional area. The number of operating recycle pumps is shown for each test. 

(The relationship between pump number and spray header location is shown on Figure 2-1.) 

"Slurry flow" is the total recycle slurry flow to the test module spray headers calculated using the 

average of three separate recycle pump flow measurements made for each pump during the 

baseline test period. The "UG" for each test was calculated u~ing this flow rate and the 

measured flue gas volume for each individual run. 

In Table A-2 for the parametric tests, the "on-site formate" concentration was 

determined by buffer capacity titration, and the "off-site formate" concentration was determined 

by ion chromatography. These results were in good agreement. 

All S02 concentrations in Tables A-1 and A-2 are reported on a dry flue gas basis, 

which is the basis of the NYSEG inlet S02 analyzer data. The "on-line inlet S02" for each run is 

the average of inlet r~adings recorded every five minutes during the outlet flue gas traverses. 

Two values are shown for the absorber outlet Method 6 S02 concentrations. The 

first value is based on the on-site titration for sulfate in the H20 2 impingers using the barium 

perchlorate titration procedure. The second value is based on the off-site ion chromatograph 

analyses for sulfate in both the isopropyl alcohol (IP A) and H20 2 impingers. In most cases, the 

IP A impinger sulfate is only a small fraction of the total and is attributed to S03 in the flue gas. 

However, occasionally, the IPA impingers contained more sulfate than could be accounted for by 

S03• Sulfate can be introduced to the IP A impinger as a result of water condensation and S02 

A-2 
TableA-1 

Actual Baseline Test Conditions and Results 

7/19/94 I 0900-1040 5.66 9.1 1,2,3,5 I 41900 I 85 I 1567 I 185 I 21

1 I 2 I 7/19/94 I 1104-1159 5.62 9.1 1,2,3,5 I 41900 I 85 I 1570 I 214 I 21

1 I 3 I 7/19/94 I 1353-1423 5.60 8.9 1,2,3,5 41900 I 87 I 1548 I 209 I 21

4 I 7119/94 I 1444-1514 I 5.60 8.8 1,2,3,5 419oo 1 88 I 1532 I 212 I 22

;J> II 1 I 5 I 7119/94 I 1534-1617 I 5.64 9.1 1,2,3,5 419oo I 86 I 1453 I 195 I 21

I 

(.;.) II • I 6 I 7/19/94 I 1635-1705 I 5.68 I 8.7 I 1,2,3,5 41900 I 85 I 1504 I 180 I 19

2 I 1 I 7/20/94 I 0943-1018 I 5.58 8.6 1,2,3,4,5 51900 111 1479 103 10

2 I 2 I 7/20/94 I 1040-1110 I 5.56 8.9 1,2,3,4,5 51900 108 1574 142 14

3 I 1 I 7/20/94 I 1403-1433 I 5.60 10.0 2,3,4 31900 59 1565 324 327 

3 I 2 I 7/20/94 I 1452-1522 I 5.58 I 9.6 I 2,3,4 31900 62 1495 312 33

4 I 1 I 7/21194 I 0824-0854 I 5.03 I 9.3 I 2,3,4 31900 63 1800 572 567 

4 I 2 I 7/21/94 I 0916-0947 I 5.00 I 9.4 I 2,3,4 31900 62 1808 582 57

5 I 1 I 7/21/94 I 1032-1103 I 5.l8 I 8.4 I 1.2.3.4,5 51900 113 1760 253 24

5 I 2 I 7/21/94 I 1121-1152 I 5.18 I 8.9 I 1,2,3,4,5 51900 107 1697 304 282 

SA I 1 I 7121/94 I 1604-1632 I 4.94 9.4 1,2,3,5 41900 82 1697 408 442 

6 I 1 I 7/22/94 I 0912-0939 I 5.653 9.4 2,3,4 I 31900 I 62 I 1683 I 195 I 20

6 I 2 I 7/22/94 I 0956-1023 I 5.643 9.2 2,3,4 I 31900 I 64 I 1700 I 193 I 195 
7 I 1 I 7/22/94 I 1045-1112 I 5.81 I 8.5 

7 I 2 I 7/22/94 I 1130-1157 I 5.82 I 8.4 

8 I 1 I 7/23/94 I 0830-0857 I 5.60 I 6.2 

> .. 8 I 2 I 7/23/94 I 0914-0941 I 5.60 I 6.3 

.!.. 

a These pH readings are questionable. 

Table A-1 

(Continued) 

1,2,3,4,5 

1,2,3,4,5 

1,2,3,4,5 51900 

1,2,3,4,5 51900 

155 

152 

I 1315 I 51 

I 1353 I 51 

7

6

I 4

I 5
TableA-2 

Actual Parametric Test Conditions and Results 

8/22/94 I 1640-1720 5.60 6.7 1,2,3,4 41600 113 530 1941 65 

2 8/23/94 I 0950-1 o 19 5.74 7.4 1,2,3,4 41600 102 530 570 1430 29 

3 8/23/94 I 1150-1218 5.60 7.9 1,2,3,4 41600 96 450 570 1361 39 

4 8/23/94 I 1351-1418 5.58 8.8 1,2,3,4 41600 86 450 510 1531 51 

5 8/23/94 I 1451-1521 5.60 8.8 1,2,3,4 41600 86 450 510 1553 52 

6 8/23/94 I 1555-1622 5.63 6.3 1,2,3,4 41600 121 435 520 1603 28 

~ 7 8/23/94 I 1647-1714 5.63 6.1 1,2,3,4 41600 124 435 520 1567 37 

2 8/24/94 I 0938-1005 5.60 9.0 1,2,3,4 41600 880 1272 25 

VI 84 800 

2 2 8/24/94 I 1026-1053 5.63 9.3 1,2,3,4 41600 82 700 880 1284 26 

2 3 8/24/94 I 1445-1512 5.67 8.6 1,2,3,4 41600 88 1000 1080 1451 24 

2 4 8/24/94 I 1535-1602 5.68 8.0 1,2,3,4 41600 95 1040 1080 1381 21 

2 5 8/25/94 I 09ll-0939 5.67 8.6 1,2,3,4 41600 87 970 1060 1328 23 

2 6 8/25/94 I 1005-1032 5.64 8.7 1,2,3,4 41600 86 970 1060 1340 25 

3 8/25/94 I 1253-1321 5.61 7.6 1,2,3,4,5 51900 123 990 1070 1809 19 

3 2 8125194 I 1347-1415 5.64 7.2 1,2,3,4,5 51900 130 990 1070 1789 17 

4 8/25/94 I 1522-1539 5.59 8.0 2,3,4 31900 72 990 1090 1729 57 

4 2 8/25/94 I 1610-1637 5.58 8.1 2,3,4 31900 71 990 1090 1738 61 

5 8126/94 I 0818-0910 5.78 6.1 1,2,3,4,5 51900 154 950 1005 1587 II 

5 2 8/26/94 I 0929-1021 5.85 6.0 1,2,3,4,5 51900 156 950 1005 1654 14 

6 8/26/94 I 1045-1113 5.87 7.7 2,3,4 31900 74 990 1010 1765 49 

6 2 8/26/94 I 1133-1200 5.88 8.4 2,3,4 31900 68 990 1010 1844 45 
7 I 1 I 8/26/94 I 1436-1505 

7 I 2 I 8/26/94 I 1524-1551 

8 I 1 I 8/26/94 I 1632-1700 I 

8 I 2 I 8/26/94 I 1718-1745 I 

9 I 1 I 8/29/94 I 0904-0954 I 9 2 8/29/94 1016-1107 

> I 9 3 8/29/94 1130-1157 I 0\ 

9 4 8/29/94 1219-1246 9 I 5 I 8/29/94 I 1517-1544 9 I 6 I 8/29/94 I 1604-1631 

10 I I I 8/30/94 

10 I 2 I 8/30/94 

2,3,4 

2,3,4 

5.20 I 8.5 I 1,2,3,4,5 5.20 1,2,3,4,5 

5.52 1,2,3,4 

5.56 7.6 1,2,3,4 5.58 8.0 1,2,3,4 

5.56 7.9 1,2,3,4 

1,2,3,4 

1,2,3,4 

1,2,3,4 

Table A·2 

(Continued) 

31900 71 31900 67 

51900 110 

51900 114 

41600 100 41600 98 41600 94 41600 95 41600 92 41600 84 41600 87 

1877 I 151 I 

1867 I 137 I 

I 1000 I 1120 I 1878 I 65 I 

1000 66 I 1450 25 I 1450 I 1520 I 1755 I 24 I 

1450 1510 1851 I 29 I 1450 1510 1827 I 29 I 

1450 1520 1713 

1450 1520 1687 

3750 3810 1508 I 8 I 
oxidation in the sample probe umbilical. The S02 concentrations in the "Off-site" column were 

corrected to include sulfate in the IPA impinger solution only if the amount in an individual 

sample greatly exceeded the average value for all of the samples. During the baseline tests, the 

only sample for which this correction was required was Test 1, Run 1. On the average, the onsite and off-site results agreed within about 1 percent. The reported "overall removal efficiency" 

for each run was calculated using the off-site results. 

The final column in Tables A-1 and A-2 shows the number of transfer units 

("NTU") calculated as In (S02ijS02ouJ for each test. The use of NTU in correlating the S02 

removal data was discussed in Section 2.4. 

Solid Phase Analyses 

Tables A-3 and A-4 show the solid-phase chemical analysis results for the baseline 

and parametric tests, respectively. The results are listed in chronological order. The sample 

description is based on the test number and run number designation used in Table A-1 for the 

S02 removal results. For example, sample B 1-1 is the first slurry sample from Baseline Test 1, 

Run 1, taken at the beginning of the first Method 6 traverse period. Sample 1-1,2 is the slurry 

sample taken in between the first and second Method 6 traverses, and sample El-2 is the slurry 

sample taken at the end of Test 1, Run 2. 

Each $lurry sample indicated in the table was filtered, and the filter cake was dried 

and weighed to determine the slurry solids content in weight percent. A portion of the dried 

solids was then digested in O.lN HCl. The portion of solids that remained undissolved is 

reported as "inerts" in weight percent of the solids. 

Also shown in the table are slurry density measurements recorded from the 

NYSEG operating logs ("NYSEG specific gravity"). These values were used to estimate the 

slurry solids content ("Estimated wt% Solids"), based on assumed values for the liquid- and 

solid-phase specific gravities. 

A-7 
TableA-3 

Results of Baseline Test Solids Analyses 

0910 1000 1150 1345 1435 1520 1610 1710 0940 1020 

7 7.32 

0.29 0.23 0.24 0.24 

1.04 0.77 0.77 0.84 

7.4 

1.075 1 

10.1 10.1 10.1 11.2 10.6 10.1 10.1 11.2 9.3 9.3 

5.64 5.58 

c NA NA 51.9 51.9 

85.4 84.5 85.6 85.8 85.5 85.1 83.0 86.0 87.9 .86.8 

86.2 85.1 85.9 86.1 85.3 85.2 83.2 86.0 87.9 86.9 

1.0 81 86.3 

1.18 1.17 1.21 1.15 

1.18 1.17 1.20 1.15 

1 1 1.16 

3.5 4.0 3.6 4.1 

wt% 81 

0.0 0.0 0.0 0.0 

11.5 11.3 13.1 9.9 

.0 0.8 0.8 0.8 

Closures 

Weight,% -5.4 -2.1 -3.1 -5.0 

Molar,% 2.1 -0.7 0.7 0.3 

% 6.4 6.4 6.4 6.4 

A-8 
Date 7/20/94 

Time 1110 

Ca,mm/g 

Mg,mm/g 

ISO,mm/g 

I Total S (as SO,), mm/g 

I SO,,mm/g 

!CO,,mm/g 0.90 

Inerts, wt% 

Solids, wt% 6.0 

·NYSEGS.G. 1.07 

'.., l wt'ff, Solids 9.3 

IPH _5.53 

~. ,C 

Reagent Utility,% 

Ca-Independent 87.9 

S04-Independent 88.2 ('{) T. ~-

Reagent Ratio 

Ca-Independent 

S04-Independent ("()_ .. . ... 

% 

Solid Solution, wt% 

1Gypsumwt% 

'CaCO,,wt% 

Inerts 

I ea. rrtf!!g 

I Mg. !Jlg/g 

SO,,mg/g 

Total S (as SO,), mg/g 

SO.,m!!/1!: 

CO,, mlifg 

Oosures 

Weight,% 

Molar,% 

IJ. % 

7120/94 7120194 

1410 1442 

7.46 

0.20 

6.29 

6.57 

0.28 

1.15 1.03 

0.89 

9.4 7.8 

1.075 1.075 

10.1 10.1 

_?.62 -~.59 

52.5 

85.1 86.5 

84.9 86.6 

~8 

1.16 

1.15 

l.l7 

4.3 

85.3 

0.0 

10.3 

0.9 

298 

5 

293 

631 

27 

62 

-3.7 

0.4 

6.4 

Table A-3 

(Continued) 

7120/94 7121/94 

1530 0830 

0.90 1.03 

6.6 9.5 

1.078 1.082 

10.6 11.2 

~6 _5.03 

88.0 86.4 

88.0 86.4 

A-9 

7121/94 7121/94 7121194 7121/94 7121/94 

0900 0945 1040 1115 1150 

7.36 7.40 7.47 

0.27 _Q.~. ~2~ 

6.28 6.41 6.49 

_§.~4 6.69 6.76 

0.26 0.28 0.27 

1.03 0.81 1.05 0.87 0.90 

0.96 1.02 

9.6 9.7 9.2 7.9 8.0 

1.082 1.084 1.079 1.076 1.075 

11.2 11.5 10.7 10.3 10.1 

_5.03 _1.98 5.15 5.22 5.13 

52.6 52.9 52.9 

86.4 89.1 86.3 88.5 882 

86.5 89.4 86.2 88.6 88.3 

85.8 88.1 87.8 

1.16 l.l3 1.13 

1.16 1.13 1.13 

1.17 l.l3 l.l4 

4.0 4.2 4.1 

84.8 86.8 87.7 

0.0 0.0 0.0 

10.3 8.7 9.0 

0.0 1.0 1.0 

294 296 299 

7 5 6 

502 513 519 . 

628 642 649 

25 27 -~6 

62 52 54 

-5.1 -3.8 -2.5 

0.4 0.2 0.2 

6.4 6.5 6.5 
Date 7/21194 7122/94 7/22/94 

Time 1610 0920 0950 

Ca,mm/g 7.72 

Mg,mm/g Q.23 

SO,,mm/g 5.50 

TotalS (as SO.), mm/g 5.70 

SO.,mm/g 0.20 

CO,,mm/g 0.69 2.51 2.24 

~rts,wt% 0.97 

Solids, wt% 7.4 11.1 10.6 

NYSEGS.G. 1.085 1.09 1.092 

Estimated wt% Solids 11.6 12.3 12.6 

pH 4.88 5.57 5.63 

,C 52.5 

Reagent Utility,% 

Ca-In dependent 90.7 69.4 71.8 

S04-Independent" 91.0 68.5 71.9 rn· 71.7 

Reagent Ratio 

Ca-lndependent 1.39 

so.-Independent 1.39 

('0: 1.40 

.% 3.5 

Solid Solution, wt% 73.9 

Gypsumwt% 0.0 

CaCO,, wt% 22.3 

Inerts 1.0 

. Ca,mg/g 309 

I Mg,mg/g 6 

SO,, mg/g 440 

Total S (as S04), mg/g 547 

so.,mgtg 19 

CO,,mg/g 134 

Closures 

Weight,% -3.1 

Molar,% 0.1 .... % 6.1 

Table A-3 

(Continued) 

7122/94 7122/94 

1035 1125 

7.72 

0.25 

5.44 

5.63 

0.19 

2.52 2.28 

1.08 

11.7 10.2 

1.091 1.087 

12.5 11.9 

5.65 5.81 

52.6 

69.2 71.2 

68.4 71.4 

70.6 

1.41 

1.40 

1.42 

3.4 

72.9 

0.0 

22.8 

1.1 

309 

6 

435 

540 

18 

137 

-3.3 

0.4 

6.1 

A-10 

7/22/94 7/23194 

1200 0835 

2.36 }.13 

9.9 8.1 

1.084 1.08 

11.5 10.9 

5.83 5.69 

70.5 85.1 

70.4 85.7 

7123/94 7/23/94 NA 

0900 9045 NA 

7.62 9.05 

0.28 0.37 

6.28 

6.46 

0.18 

1.18 1.07 9.14 

1.03 1.62 

9.1 8.2 NA 

1.08 1.08 

10.9 10.9 

5.61 5_2) NA 

52.3 NA 

84.5 85.8 

85.0 86.5 

81.8 

1.18 

1.18 

1.22 

2.8 

83.6 

0.0 

11.8 

1.0 

305 362 

7 9 

. 502 0 

620 0 

17 0 

71 549 

-2.9 -6.4 

1.6 1.5 

6.4 6.9 
TableA-4 

Results of Parametric Test Solids Analyses 

0950 1026 1133 1400 1435 1558 1624 0953 1015 1052 

7.24 7.29 7.27 7 

5.84 

0.30 

1.13 0.87 1.14 9.94 1.11 0.85 0.77 0.98 1.80 2.47 

0.64 

7.7 8.7 10.4 

1.07 1.07 1.07 1.07 1.07 1.072 1.073 1.068 

9.3 9.3 9.3 9.3 9.3 9.7 9.8 9.0 9.0 9.0 

5.76 5.79 5.61 5.58 5.63 5.6 

85.8 88.7 88.7 76.9 85.4 89.1 90.0 86.2 77.3 71.3 

84.4 88.0 84.2 73.4 84.8 88.6 89.7 86.6 75.4 66.2 

94.1 94.1 94.1 88.8 92.4 83.9 

1.13 1.17 1.11 1.29 

1.14 1.18 1.11 1.33 

1.06 1.13 1.08 1. 

4.8 

0.0 

8.7 18.0 

Inerts 0.8 0.6 0.7 0.6 

Closures 

Weight,% -4.0 -5.5 -3.0 -4.2 

Molar,% -3.0 -2.0 -1.3 -4.1 

% 6.6 6.5 6.5 6.3 

A-ll 
1454 1520 

7 

0.36 

6.03 

0.35 

1.69 1.43 

79.1 81.7 

77.8 81.2 

83.8 

1.22 

1.23 

0.0 

14.3 

9 

482 

0 

33 

86 

Closures 

Weight,% -3.6 

Molar,% -1.3 

% 6.2 

1613 

1.3 

9.2 

5.68 

83.1 

82.9 

TableA-4 

(Continued) 

0920 0949 

5.91 

0.34 

1.52 1.53 

7.8 7.8 

5.64 5.67 

49.8 

80.4 80.3 

78.9 78.8 

1.24 

1.27 

1.15 

81.1 

0.0 

15.3 

0.8 

-5.1 

-3.8 

6.3 

A-12 

1037 1254 1342 1422 1608 

7.18 

6.13 

0.8 0.61 0.98 1.82 1.12 

10.2 

1.06 1.077 

7.8 7.8 7.8 7.8 10.4 

5.64 5.67 

88.6 91.4 86.9 78.2 85.5 

8.9 91.5 86.3 74.6 85.2 

90.8 87.5 

1.15 1.17 

1.16 1.17 

1.10 

84.7 

0.0 0.0 

9.8 11.2 

490 

59 

-6.2 -3.5 

-2.2 -1.1 

6.5 6.3 
1644 0831 0942 

81.3 78.6 81.3 

79.9 75.4 79.3 

90.2 

1.23 

1.26 

1 

4.5 

286 

0 

493 

0 

28 

Closures 

Weight, o/o -4.0 

Molar, o/o -5.2 

% 6.3 

Table A-4 

(Continued) 

1030 1123 

5.75 

82.6 75.3 

83.6 74.5 

77.8 

1.33 

1.34 

10 

460 

-3.3 

-1.6 

6.1 

A-13 

1208 14455 1523 1602 1712 

7.12 

6.09 

78.2 81.7 81.5 88.3 90.6 

78.3 79.8 79.6 88.1 90.4 

1 

1.23 1.10 

1.26 1.11 

1 

525 

0 0 

31 31 

-4.5 -3.9 

-4.9 -1.4 

6.3 6.5 
1750 0908 1000 

c 

89.6 85.6 88.2 

889.2 84.2 87.4 

94.3 

1.13 

1.14 

1 

0.8 

286 

0 

26 

Oosures 

Weight,% -4.8 

Molar,% -3.3 

% 6.6 

TableA-4 

(Continued) 

1114 1213 

5.96 

85.9 80.6 

85.6 79.0 

87.5 

1.24 

1.27 

1.14 

284 

0 

477 

0 

-6.2 

-4.1 

6.3 

A-14 

83.2 80.7 

82.4 78.5 

87.3 88.9 85.0 89.0 

86.9 88.8 83.6 88.5 

90.0 92.9 

1.15 1.12 

1.15 1.13 

1 1.08 

7 

522 

7 0 

26 25 

50 

-4.6 -4.5 

-1.5 -2.2 

6.4 6.5 
The digested solids solution was analyzed for ca++ and Mg++ by atomic absorption 

and for S04 = by ion chromatography (IC). A separate portion of the dried solids was analyzed for 

SOt (sulfite) by thiosulfate/iodine titration. A third portion of the dried solids was analyzed for 

C03= (carbonate) by coulometric measurement of C02 gas evolved from an acidified sample. 

These analytical methods are described in detail in EPRI's FGD Chemistry and Analytical 

Methods Handbook. 

Two calculated values for limestone utilization are reported in Tables A-3 and A-4 

following the analytical results. Utilization is defined as [1 -moles of carbonate/(moles of 

product solids+ moles of carbonate)]. The "Ca-independent" value for utilization is calculated 

using the totalS (sulfite plus sulfate) analysis as the total moles of product. The "S04-

independent" value is calculated using the Ca analysis as the total moles of product + moles of 

carbonate. For samples with only carbonate analyses, approximate utilizations were calculated 

by using the calcium and sulfite/sulfate analyses for the closest sample from the same test that 

was completely analyzed. The calculated utilization values are also expressed as reagent ratio, 

which is the inverse of utilization (expressed as a fraction rather than as a percentage). 

Sulfite oxidation percentages reported in Tables A-3 and A-4 are calculated as 100 

x [1 -moles of sulfite/moles of total sulfite plus sulfate]. 

The remaining entries in Tables A-3 and A-4 include solids analyses calculated on 

a weight basis, follo'o/ed by calculated "closures" for the analytical results. Closures are 

calculated as a quality assurance indicator. The molar closure in percent is calculated for a given 

set of solids analyses as the difference between the sums of positively and negatively charged 

ionic species in moles/gram divided by the total of the positively and negatively charged species 

in moles/gram (times 100). The calculated "acceptable" closure in percent is the expected error 

in the calculated molar closure at the 95% confidence level based on the assumptions that each of 

the individual analyses has a standard deviation of ±5% and that all significant species have been 

included in the analyses. The calculated closures in Tables A-3 and A-4 indicate good data 

quality for the solids analyses. All of the molar closures are well below the acceptable limits. 

A-15 
The calculated limestone utilization values in Table A-4 (plotted in Figure 2-6) 

were scattered. This could be due to pH measurement, slurry sampling, or analytical problems. 

In order to check for analytical problems, six solid samples from Parametric Test 2, during which 

the slurry pH varied no more than ±0.05, were reanalyzed for carbonate. The results of these 

replicate analyses are shown in Table A-4 in parentheses below the original carbonate results. 

The analytical agreement was excellent, so the scatter in the utilization data is more likely related 

to slurry sampling problems. 

Another discrepancy in the solid-phase analytical results for the parametric tests 

can be seen by examining the slurry solids contents ("solids, wt%" in the tables). Material 

balance calculations show that, at full load, the maximum rate of increase in the slurry solids 

content in the test module reaction tank should be about 0.5 wt% per hour even if no slurry was 

bled from the tank. Inspection of t~e parametric test data shows that the measured slurry solids 

content increased or decreased by as much as 3 or 4 percentage points in less than one hour. 

There are two possible sampling problems that could account for these results. 

Either the slurry samples drawn from the sample tap were not representative of the hydroclone 

feed stream, or the tank was not well mixed at the location of the hydroclone feed pump suction. 

Because of this sampling problem, the NYSEG slurry specific gravity measurements have been 

used to estimate slurry solids contents when required for process calculations. 

Liquid Analyses 

Tables A-5 and A-6 show results of the liquid-phase analyses for the baseline and 

parametric test filtered slurry samples. Calcium, magnesium, and sodium were determined by 

atomic absorption spectrophotometry. Chloride, sulfite, sulfate, and thiosulfate were determined 

by ion chromatography. The reported result for "total hydrolyzable sulfate" is the total sulfate 

measured in the liquor sample after digestion under acidic oxidizing conditions, which converts 

all sulfur species to sulfate. The final result reported as "sulfur/nitrogen" species (SIN in the 

A-16 
Table A-5 

Results of Baseline Test Liquid Analyses 

1020 1442 0900 1115 0950 

104 105 107 106 

178 181 189 187 179 

3.6 4.4 4.2 3.7 4.2 4.3 4.1 4.5 4.3 3.1 

5. 5.74 

2.32 2.01 1.99 2.91 1.90 2.58 2.66 0.62 0.59 0.59 

1 2.09 2.02 2.15 2.05 2.21 2.20 2.31 2.34 2.40 

23.0 23.3 22.5 20.1 24.3 23.2 26.9 20.3 18.9 21.2 

11.2 11.2 10.9 7.1 12.5 9.3 12.7 9.8 11.2 10.4 

5.64 5.60 

51.9 51.9 52.5 52.6 52.9 52.5 52.6 52.3 

4250 4180 41 4270 4240 3900 3750 

4260 4340 4410 4580 4540 4350 4340 4330 

1160 1240 1220 1160 1190 1160 

20000 20700 20600 20000 20500 

219 262 253 224 251 

474 446 460 460 553 565 421 191 426 

193 256 60 56 57 

220 234 247 259 262 269 

Charge Imbalance 

Calculated, % 1.8 0.5 0.7 2.4 1.7 2.3 0.8 1.5 1.1 0.7 

% 5.9 5.9 5.9 5.9 5.9 5.9 

Relative Saturation 

Gypsum 0.10 0.09 0.09 0.12 0.08 0.11 0.11 0.03 0.02 0.02 

CaS03 *0.5H20 8.0 8.1 8.3 7.7 7.7 4.1 5.7 8.5 3.9 6.9 

0.13 0.14 0.18 0.11 0.13 0.014 O.Q3 0.29 0.29 0.10 

A-17 
Table A-6 

Results of Parametric Test Liquid Analyses 

1026 1435 1624 1015 1520 0949 1342 1608 0942 1123 

47.2 48.6 47.9 48.6 48.1 47.0 45.9 45.4 42.3 42.3 

216 211 

73.9 75.6 

481 479 490 

4.41 4.70 

4.04 4.66 3.96 4.94 4.07 4.36 4.20 4.10 3.23 3.30 

11.34 9.77 9. 5.01 4.97 

1.90 2.01 2.20 

26.0 26.4 

9.3 8.9 12.9 8.8 13.0 13.8 8.5 12.4 12.8 

11.4 11.5 19.6 23.5 23.8 24.2 22.3 22.5 

5.63 5.58 5.67 5.67 5.64 5.59 5.83 5.88 

50.3 48.0 7 50.6 

1920 1950 1930 1880 1840 1820 1690 1690 

0 5130 

0 0 1390 0 1700 0 0 1740 0 0 

0 0 17100 0 17000 0 0 17400 0 0 

278 294 265 282 68 325 222 316 

323 373 317 395 326 349 336 328 258 264 

810 1160 928 999 1090 938 900 821 481 

0 0 212 0 225 0 0 246 0 0 

1010 

Ch¥ge Imbalance 

Calculated, % 4.9 4.9 5.3 4.4 4.2 1.8 1.5 2.0 5.4 5.2 

% 7.7 7.5 6.0 7.6 5.9 7.8 7.7 6.0 8.1 1 

Relative Saturation 

Gypsum 0.20 0.25 0.20 0.22 0.23 0.20 0.19 0.17 0.09 0.09 

CaS03 *0.5H20 3.4 3.4 2.9 3.3 3.1 3.3 3.0 2.7 2.6 2.8 

0.13 0.08 0.08 0.07 0.10 0.02 0.08 0.08 0.12 0.20 

A-18 
1523 1712 

43.6 42.0 

213 

5.00 3.86 

9.86 

5.31 6.25 

2.46 

28.4 29.2 

9.6 

24.6 24.9 

5.13 5.24 

5 8 

1750 1680 

0 5190 

0 16900 

300 232 

789 680 

1 

0 275 

1110 1120 

Charge Imbalance 

Calculated, % 4.7 4.7 

% 

Relative Saturation 

Gypsum 0.10 0.11 

CaS03*0.5H20 3.0 3.0 

CaC03 0.01 0.01 

TableA-6 

(Continued) 

1000 

. 4.86 

5.19 

29.3 

17.3 

33.8 

5.48 

1600 

0 

0 

292 

545 

0 

1520 

2.7 

0.09 

3.4 

0.04 

A-19 

1213 

5.25 

18 

4.95 

28.3 

18.2 

33.5 

5.56 

1550 

315 

415 

0 

1510 

2.6 

0.08 

2.8 

0.06 

1554 1122 

37.2 

222 219 

503 484 

4.95 5.60 

4.32 

28.3 34.5 

5.54 5.68 

1550 1490 

289 279 

469 423 

484 498 

1520 3810 

3.3 4.0 

6.1 

0.08 0.07 

3.1 3.1 

0.05 0.08 
TableA-7 

Results of ICPES Analyses for Baseline and Parametric Test Liquids 

ND ND ND ND 

ND ND ND ND 

0.6 ND ND ND 

0.3 0.1 0.1 0.1 

ND ND ND ND 

Boron 640 560 540 550 

Cadmium 0.008 ND 0.02 0.01 

Calcium 4230 1860 1780 1470 

Chromium <0.03 ND ND 0.01 

Cobalt <0.03 0.01 0.04 0.01 

<0.06 <0.04 <0.03 0.02 

Iron 0.5 ND ND 0.6 

Lead ND ND ND ND 

Lithium 0.8 0.8 0.8 0.8 

4310 4750 4550 4760 

0.9 0.3 0.4 0.3 

<0.05 <.03 0.1 0.05 

Nickel 0.9 0.7 0.7 0.7 

Potassium 61 54 53 54 

Selenium 0.6 <0.4 0.5 0.4 

Silicon 7.7 6.1 5.6 7.1 

Silver ND <0.02 ND ND 

Sodium 1140 1340 1590 1890 

2.5 2.4 

A-20 
Sulfur 

Thallium 

Tin 

Titanium 

NA = Not analyzed 

ND = Not detected 

1030 

0.1 

<0.09 

ND 

0.2 

1.6 

0.07 

TableA-7 

(Continued) 

NA 

0.2 

<0.07 

ND 

NA 

ND 

0.02 

A-21 

NA NA 

ND ND 

ND ND 

ND ND 

NA NA 

ND ND 

0.03 0.04 
table) represents the difference between the total hydrolyzable sulfate and the sum of the moles 

of sulfur in the other individually reported sulfur species. 

Calculated molar closures (charge imbalances) have again been used as a data 

quality check. All of the calculated charge balances are well within acceptable limits. 

A-22 

APPENDIXB 

Detailed Formate Material Balance Data 

and Chemical Analyses Results for the Sodium Formate Consumption Test 

B-1 

Table B-1 shows detailed sodium formate material balance data for the 

consumption test. During the three inventory days of the consumption test, formate 

concentrations were measured in most of the major system vessels. The actual liquid formate 

concentrations were measured for the reaction tanks, limestone slurry tanks, thickeners, and 

filtrate. The concentrations in the underflow storage tanks were assumed to be the same as that 

in the filtrate. The concentration in the supernate tank was taken as the average of the 

concentrations in the two limestone slurry tanks. 

Each page of Table B-1 represents one consumption test inventory. For tanks that 

operate with variable levels, the level of each tank was also measured: The formate inventory in 

each system vessel is calculated in the rows at the top of each page. For example, the "B" 

module reaction tanks contained.l,OOO mg/L formate (as formate ion) on the first day (917/94). 

The total reaction tank volume was about 346,000 gallons. The estimated formate inventory in 

the liquid inventory for this module was 2,744lbs. The formate content of the solids in each tank 

was not measured, but was assumed to be the same as that measured in the filter cake solids. The 

amount of formate in the solid phase is much less than that in the liquid phase. The formate 

inventory change term in the material balance for a given test period was calculated as the 

difference in the total liquid-phase formate inventory at the beginning and end of the test period. 

The total system liquid- and solid-phase formate inventory is shown at the bottom 

of columns 8 and 10. On the first 'day of the test, the liquid inventory was about 39,000 lbs~ and 

the solid inventory was about 1,700 lbs (as formate ion). The next entry below the inventory 

estimate is the total inventory change since the previous day. This entry (as well as other entries 

below) is "0" for the first day. 

The next group of three entries are the amounts of 40% sodium formate solution in 

the tanker in gallons and pounds and the calculated amount added since the previous test day. 

These amounts were determined by gauging the tanker. Note that the tanker was refilled with 

45,500 lbs of sodium formate solution between the second and final inventories. 

B-2 
TableB-1 

DATE: 9/07/94 Detailed Formate Material Balance Data 

Time: 0700 

Tank Tank Tank Liquid Formate Formate Formate 

Multiplier Height Height Tank Vol. Formate Estimated in Liquid in Solids in Solid

Sample location (gal/ft) (%) ( ft) (gal) (mg/L) %Solids (1 b) (%) (1 b

-------------------

-------- --------- ---------

--------- ---------

--------- --------- --------

A MODULE 14420 100 24 346080 0 9.3 D 0.000 

B MODULE 14420 100 24 346080 1000 11.0 2744 0.074 25

C MODULE 14420 100 24 346080 1045 9.3 2891 0.074 21

D MODULE ' 14420 100 24 346080 0 9.3 0 0.000 

E MODULE 14420 100 24 346080 1090 7.6 3040 0.074 17

F MODULE 14420 100 24 346080 1045 9.3 2891 0.074 21

A THICKENER 133000 10.5 1396500 810 0.0 9432 0.074 

B THICKENER 133000 11.2 1489600 1170 3.0 14350 0.074 28

LS SLURRY STORAGE A 7200 64 20.5 147456 765 35.0 767 0.000 

LS SLURRY STORAGE B 7200 90 28.8 207360 905 35.0 1276 0.000 

UNDERFLOW STORAGE A 6400 42 13.0 83328 1080 40.0 586 0.074 27UNDERFLOW STORAGE B 6400 50 15.5 99200 1080 40.0 697 0.074 32

b:J SUPERNATE TANK 6790 9.5 64505 835 0.0 449 

I FILTRATE TANK 1700 11.0 18700 1080 0.0 168 w 

TOTALS 5583129 39291 173TOTAL LIQUID-PHASE FORMATE INVENTORY CHANGE 0 

TANKER LEVEL (GAL) 5999 

40% SODIUM FORMATE IN TANKER (LBS) 63964 40% SODIUM FORMATE ADDEO SINCE LAST INVENTORY (LBS) 0 

LIMESTONE USED SINCE LAST INVENTORY (TONS) 0 

ASSUMED AVERAGE UTILIZATION (%) 90 

TONS S02 REMOVED SINCE LAST INVENTORY (BASED ON LIMESTONE) 0 TONS S02 REMOVED SINCE LAST INVENTORY (BASED ON CEM) 0 

FILTER CAKE PRODUCED SINCE LAST INVENTORY (TONS) 0 

AVERAGE CAKE SOLIDS CONTENT (%) 76 

FORMATE LOST WITH CAKE LIQUID SINCE LAST INVENTORY (LBS) 0 

FORMATE LOST WITH CAKE SOLIDS SINCE LAST INVENTORY (LBS) 0 FORMATE SOLUTION LOSS (LB/TON S02) 0 

FORMATE NON SOLUTION LOSS (LB/TON S02) 0 

TOTAL FORMATE CONSUMPTION (LB/TON S02) 0 

TOTAL SODIUM FORMATE CONSUMPTION (LB/TON 502) 0 
Table B-1 

DATE: 9/09/94 (Continued) 

Time: 0710 

Tank Tank Tank Actual Liquid Formate Formate Forma

Multiplier Height Height Tank Vol.· Formate Estimated in Liquid in Solids in Sol i

Sample lodation (gal/ft) (%) (ft) (gal) (mg/L) %Solids ( 1 b) (%) ( 1 

---------------- --------- -------- --------- --------- --------- --------- --------- --------- -------

A MODULE 14420 100 24 346080 0 9.3 0 0.000 

B MODULE 14420 100 24 346080 1050 15.1 2820 0.076 3

C MODULE 14420 100 24 346080 1140 12.9 3097 0.076 3

D MODULE 14420 100 24 346080 0 9.3 0 0.000 

E MODULE 14420 100 24 346080 1080 11.2 2961 0.076 2

F MODULE 14420 100 24 346080 1200 18.3 3165 0.076 4

A THICKENER 133000 10.5 1396500 710 0.0 8267 0.076 

B THICKENER 133000 11.2 1489600 1300 3.0 15945 0.076 2

LS SLURRY STORAGE A 7200 90 28.8 207360 970 35.0 1367 0.000 

LS SLURRY STORAGE B 7200 64 20.5 147456 990 35.0 992 0.000 

UNDERFLOW STORAGE A 6400 55 17.1 109120 1100 40.0 781 0.076 3

UNDERFLOW STORAGE B 6400 62 19.2 123008 1100 40.0 881 0.076 4

t:rJ SUPERNATE TANK 6790 9.5 64505 980 0.0 527 

FILTRATE TANK 1700 11.0 18700 1100 0.0 172 

TOTALS 5632729 40975 24TOTAL LIQUID-PHASE FORMATE INVENTORY CHANGE SINCE 9/7 (LBS) 1684 

TANKER LEVEL (GAL) 4103 

40% SODIUM FORMATE IN TANKER (LBS) 43748 

40% SODIUM FORMATE ADDED SINCE LAST INVENTORY (LBS) 20216 

LIMESTONE USED SINCE 9/7 INVENTORY (TONS) 815 

ASSUMED AVERAGE UTILIZATION (%) 90 

TONS S02 REMOVED SINCE 9/7 INVENTORY (BASED ON LIMESTONE) 427 TONS 502 REMOVED SINCE 9/7 INVENTORY (BASED ON CEM) 522 

FILTER CAKE PRODUCED SINCE 9/7 INVENTORY (TONS) 1316 

AVERAGE CAKE SOLIDS CONTENT (%) 76 

FORMATE LOST WITH CAKE LIQUID SINCE LAST INVENTORY (LBS) 697 

FORMATE LOST WITH CAKE SOLIDS SINCE LAST INVENTORY (LBS) 1494 FORMATE SOLUTION LOSS (LB/TON S02) 1.3 

FORMATE NON SOLUTION LOSS (L8/TON S02) 5.7 

TOTAL FORMATE CONSUMPTION (LB/TON S02) 7.0 

TOTAL SODIUM FORMATE CONSUMPTION (LB/TON S02) 10.6 
Table B-1 

DATE: 9/12/94 (Continued) 

Time: 071D 

Tank Tank Tank Actual Liquid Formate Formate Formate 

Multiplier Height Height Tank Vol. Formate Estimated in Liquid in Solids in Solid

Sample location (gal/ft) (%) (ft) (gal) (mg/L) % Solids (1 b) (%) ( 1 b

----------------

--------- -------- --------- ---------

--------- --------- ---------

--------- --------

A MODULE 14420 100 24 346080 0 9.3 0 0.000 

B MODULE 14420 100 24 346080 1045 12.9 2839 0.089 36

C MODULE 14420 100 24 346080 1100 15.2 2952 0.089 43

D MODULE 14420 10D 24 346080 0 9.3 0 0.000 

E MODULE 14420 100 24 346080 1070 9.8 2953 0.089 27

F MODULE 14420 100 24 346080 1250 14.4 3370 0.089 40

A THICKENER 133000 10.5 1396500 850 0.0 9897 0.089 

B THICKENER 133000 11.2 1489600 900 3.0 11039 0.089 34

LS SLURRY STORAGE A 7200 70 22.4 161280 990 35.0 1085 0.000 LS SLURRY STORAGE B 7200 91 29.1 209664 990 35.0 1411 0.000 

UNDERFLOW STORAGE A 6400 51 15.8 101184 1100 40.0 725 0.089 39

UNDERFLOW STORAGE B 640D 63 19.5 124992 llOO 40.0 895 0.089 48

o; SUPERNATE TANK 6790 9.5 64505 990 0.0 532 

I FILTRATE TANK 1700 11.0 18700 1100 0.0 172 VI 

TOTALS 5642905 37870 270TOTAL LIQUID-PHASE FORMATE INVENTORY CHANGE SINCE 9/9 (LBS) -3105 

TANKER LEVEL (GAL) 5534 

40% SODIUM FORMATE IN TANKER (LBS) 59006 40% SODIUM FORMATE ADDED SINCE LAST INVENTORY (LBS) 30322 

LIMESTONE USED SINCE 9/9 INVENTORY (TONS) 1525 

ASSUMED AVERAGE UTILIZATION (%) 90 

TONS S02 REMOVED SINCE 9/9 INVENTORY (BASED ON LS) 799 

TONS S02 REMOVED SINCE 9/9 INVENTORY (BASED ON CEM) 824 

CAKE PRODUCED SINCE 9/9 INVENTORY (TONS) 2007 

AVERAGE CAKE SOLIDS CONTENT (%) 77 

FORMATE LOST WITH CAKE LIQUID SINCE LAST INVENTORY (LBS) 1007 FORMATE LOST WITH CAKE SOLIDS SINCE LAST INVENTORY (LBS) 2557 FORMATE SOLUTION LOSS (LB/TON S02) 1.2 FORMATE NON SOLUTION LOSS (LB/TON S02) 12.3 

TOTAL FORMATE CONSUMPTION (LB/TON S02) 13.5 TOTAL SODIUM FORMATE CONSUMPTION (LB/TON S02) 20.4 
The next group of entries includes data used to estimate the total tons of S02 

removal for each test day. Daily limestone weigh belt readings and differences in limestone 

slurry tank levels from day to day were used for one estimate of S02 removal. The solids content 

of the limestone slurry and the average utilization had to be assumed for this calculation. This 

result is shown as "tons S02 removed since last inventory (based on LS)." The next line, "tons 

S02 removed since last inventory (based on CEM)," was estimated using the average unit load, 

unit heat rate, and inlet and outlet CEM data in lbs of S02 per million Btu heat input. This value 

is expected to be more accurate than the value estimated from limestone consumption. 

The next group of entries estimate the amount of formate leaving the system with 

the filter cake. The amount of filter cake produced since the last inventory was provided by 

NYSEG from weigh belt readings. The solids content of the filter cake was measured. The 

formate concentration in the filter cake liquid was assumed to be the same as that of the filtrate, 

which was measured. 

On the second and third pages of Table B-1, the concentrations of formate in each 

vessel are shown for the second and third inventory days, and the calculated quantities appear as 

described above. The final four entries show the calculated solution and nonsolution loss rates 

and the total formate and sodium formate consumption rates since the previous inventory. The 

overall average consumption results shown in Table 2-3 were calculated for the period between 

the first and final inventories. 

Slurry samples were obtained from each of the operating modules during the 

consumption test. Results of the solid- and liquid-phase analyses are shown in Tables B-2 and 

B-3. In these tables, the sample designation "B-917", for example, refers to the slurry sample 

from the B Module taken during the 917/94 inventory. The remainder of the tables have the same 

format as those presented for the baseline and parametric test slurry analyses. The molar closure 

results for the long-term solid and liquid analyses indicate good data quality for all of the samples 

except solid C-9/12. The calcium analysis for this sample appears to be low. 

B-6 
TableB-2 

Results of Consumption Test S,Olids Analyses 

0758 0744 0810 0756 

7.18 7.21 7.22 6.15 

0.30 0.19 0.36 0.12 

6.58 6.53 6.66 6.23 6.72 

6.77 6.68 6.85 6.37 7.08 6.93 

0.16 0.21 

0.60 0.74 

0.80 0.96 1.00 1.04 

5.3 9.2 10.8 

1.059 

c 50.1 51.1 51.1 

87.5 86.7 88.7 80.8 92.2 90.4 91.6 84.7 88.1 88.0 

87.2 86.4 88.2 80.1 90.4 90.0 91.3 84.3 87.7 87.5 

89.3 89.3 84.1 113 93.5 95.1 87.2 90.7 91.6 

1.14 1.15 1.13 1.24 1.08 1.11 1.09 1.18 1.14 1.14 

1.15 1.16 1.13 1.25 1.11 1.11 1.10 1.19 1.14 1.14 

1.12 1.12 1.08 1.19 0.88 1.07 1.05 1.15 1.10 1.09 

wt% 

0.0 

9.2 

0.9 

289 

7 

508 

650 641 658 665 673 627 651 648 

18 14 19 20 20 18 14 14 

52 44 71 55 55 

Closures 

Weight,% -3.0 -3.9 -3.4 -3.6 -7.4 -3.2 -3.3 -3.9 -3.5 -4.4 

Molar,% -1.0 -1.4 -2.1 -2.0 -10.2 -1.7 -1.9 01.4 -1.5 -2.0 

Acceptable, % 6.5 6.4 6.5 6.3 6.7 6.6 6.6 6.4 6.5 6.5 

B-7 
TableB-3 

Results of Consumption Test Liquids Analyses 

0824 0810 

32.3 31.2 

226.5 

84.4 89.4 90.9 107.4 91.0 85.6 86.7 87.2 94.4 

470.6 495.3 498.0 532.3 510.2 482.0 491.7 479.7 537.8 

6.4 5.3 7.2 6.0 7.0 5.9 5.5 7.4 

4.7 4.4 6.2 4.6 5.7 5.6 5.3 6.8 

3.4 3.2 3.9 2.9 3.3 4.5 4.0 3.7 

422 356 332 446 

457 451 421 541 

315 431 381 351 279 

764 796 

1071 1202 

2.7 2.9 1.3 2.4 

% 6.1 6.1 6.1 6.1 

Relative Saturation 

Gypsum 0.05 0.04 0.05 0.04 0.04 0.06 0.05 0.05 0.04 0.03 

CaS03*0.5H20 2.5 2.4 2.5 2.5 2.6 3.1 2.4 3.3 2.3 2.2 

0.09 0.08 0.05 0.09 O.Q7 0.10 0.05 0.08 0.08 0.12 

B-8 

APPENDIXC 

Other Process Data 

C-1 

<l 

tS 

Table C-1 

Other Process Data for the Baseline and Parametric Tests 
B-8 2 7/23/94 I 0914-0941 709 3.0 

Inlet 8/22/94 I 0950-1010 690 3.0 

Inlet 8122/94 I 1036-1056 694 2.9 

Inlet 8/22/94 I ll14-ll34 699 3.0 

("') P-1 8/22/94 I 1640-1720 690 3.0 

I 

w P-1 2 8/23/94 I 0950-1019 406 6.4 

P-1 3 8/23/94 I 1150-1218 386 6.6 

P-1 4 8/23/94 I 1351-1418 477 5.6 

P-1 5 8/23/94 I 1451-1521 489 5.5 

P-1 6 8/23/94 I 1555-1622 510 5.0 

P-1 7 8/23/94 I 1647-1714 502 5.3 

P-2 8/24/94 I 0938-1005 282 6.8 

P-2 2 8/24/94 I 1026-1053 290 6.7 

P-2 3 8/24/94 I 1445-1512 424 6.4 

P-2 4 8/24/94 I 1535-1602 382 6.5 

P-2 5 8/25/94 I 1911-0939 398 6.3 

P-2 6 8/25/94 I 1005-1032 432 6.0 

P-3 8125194 I 1253-1321 670 3.0 

P-3 2 8/25/94 I 1347-1415 674 3.1 

6.6 5 

6.8 4 

6.7 4 

6.8 4 

6.7 4 

9.9 3 

10.1 3 

9.1 3 

9.0 3 

8.4 4 

8.8 4 

10.3 2 

10.2 2 

9.6 3 

9.6 3 

9.5 3 

9.0 3 

6.5 4 

6.6 4 

Table C-1 

(Continued) 

1320 3.23 

1876 4.50 

1875 4.51 

1905 4.54 

1941 4.65 

1430 4.28 

1361 4.26 

1531 4.40 

1553 4.39 

1603 4.42 

1567 4.38 

1272 4.04 

1284 4.07 

1451 4.20 

1381 4.11 

1328 3.97 

1340 4.10 

1809 4.22 

1789 4.20 

0.51 12.1 12.7 515 

0.55 11.5 126 524 

0.56 11.6 126 525 

0.57 11.7 127 523 

0.55 11.7 127 522 

0.54 8.8 129 430 

0.55 8.6 130 434 

0.57 9.5 128 454 

0.58 9.6 128 470 

0.49 9.9 127 

0.54 9.8 128 464 

0.54 8.4 128 283 

0.57 8.4 131 303 

0.95 124 333 

0.26 8.5 123 351 

123 328 

124 363 

127 481 

127 477 
(1 

,!:,. 

P-4 8/25/94 I 1522-1539 673 3.0 7.1 P-4 2 8/25/94 I 1610-1637 682 3.0 P-5 8/26/94 I 0818-091 o 535 4.7 8.0 P-5 2 8/26/94 I 0929-1021 571 4.4 7.9 P-6 8/26/94 I 1045-1113 643 3.3 7.0 P-6 2 8/26/94 I 1133-1200 680 3.0 6.6 P-7 8/26/94 I 1436-1505 665 3.0 6.7 P-7 2 8/26/94 I 1524-1551 670 3.0 6.5 P-8 8126194 I 1632-1700 681 3.0 6.5 

P-8 2 8/26/94 I 1718-17 45 695 3.0 6.5 

P-9 8/29/94 I 0904-0954 574 4.2 8.0 P-9 2 8/29/94 I 1016-1107 615 3.8 7.2 P-9 3 8/29/94 I 1130-1157 655 3.2 6.9 

P-9 4 8/29/94 I 1219-1246 646 3.2 6.9 

P-9 5 8/29/94 I 1517-1544 555 4.7 8.1 P-9 6 8/29/94 I 1604-1631 552 4.7 8.1 

P-10 8/30/94 I 0948-1108 373 6.5 9.8 

2 8/30/94 8 

(I) Boiler% 0 2 is average of east and west monitors. 

(2) ID fan motor current is sum of amps on fans lA, IB, and 1C. 

(3) Bypass damper A position is shown; other bypass dampers are closed. 

4 

4 

4 

4 

4 

4 4 

4 

4 4 

4 

4 4 4 

4 4 

3 3 

Table C-1 

(Continued) 

1729 4.23 1738 

1587 4.33 

1654 4.38 

1765 4.43 

1844 4.40 

1877 4.40 

1867 4.41 

1878 4.38 

1868 4.39 

1677 4.36 

1755 4.36 

1851 4.43 

1827 4.48 

1713 4.47 

1687 4.51 

1508 4.59 

0.30 11.5 127 543 0.48 11.5 127 522 

0.56 9.9 128 498 

0.57 10.5 128 388 

0.58 11.4 127 438 0.58 11.5 129 481 0.46 11.2 130 483 

0.48 11.3 130 492 0.51 11.3 129 496 0.40 11.4 129 516 

0.31 10.5 123 393 

0.36 10.9 126 462 

0.37 11.3 127 450 0.39 11.3 127 455 0.25 10.0 123 419 0.23 10.0 123 419 0.28 8.7 122 320 

0.28 8.7 120 316 
TableC-2 

Other Process Data for the Sodium Formate Consumption Test a 

917194 573 4.2 7.7 3.69 0.48 10.6 I 129 I 440 I 

919194 662 3.1 6.9 4.02 0.50 11.3 I 130 I 472 I 

n 9110/94 667 3.1 6.9 3.96 0.43 11.4 129 467 I 

I VI 

9/11194 627 3.6 7.4 4.46 0.54 10.9 128 450 I 9/12/94 652 3.3 7.0 4.42 0.54 11.1 128 453 I 

a Data represent average conditions for the previous 24-hour period as of 0700 on each day. 

b Stack S02 includes partial bypass. 
APPENDIXD 

FGDPRISM Calibration 

D-1 

The FGDPRISM calibration involves an iterative process in which the parameters 

are adjusted to obtain the best overall fit to the performance data. The steps used in the Kintigh 

FGDPRISM calibration procedure are summarized below: 

1. Test results were reviewed to select data sets representative of each 

baseline and parametric test. Each test had two or more runs that provided 

S02 performance data and samples for laboratory analysis. Baseline Tests 

2 and 5, and Parametric Test 10, were selected for use in the calibration. 

The intent was to select tests with similar gas velocities but a wide range of 

S02 removal efficiency. 

2. Liquid-phase analyses from the selected tests w~re input into the 

FGDPRISM equilibrium module to determine partial pressure of C02 and 

relative saturations of CaC03, CaS03•Yili20, CaS04•Y2H20, and 

CaS04•2H20. 

3. The FGDPRISM material balance module was run for each calibration 

case, and the following inputs were adjusted to best match the flue gas, 

liquid, and solid compositions: 

• Unit load (gas velocity); 

• Coal percent sulfur (FGD inlet S02 concentration); 

• Reagent ratio (LS utilization and slurry pH); 

• CaS03 RS multiplier (RS of CaS03•Yili20); 

• Percent oxidation (S04 in liquid and solid); 

• Coal chloride content (Cl in liquid); 

• Limestone MgC03 solubility (Mg in liquid); 

• Makeup water sodium content (Na in liquid); and 

• Makeup water magnesium content (Mg in liquid). 

4. 'Using the FGDPRISM complete system simulation, adjustments were 

made to the following FGDPRISM system simulation inputs to obtain the 

best fit to the three calibration cases: 

• Gas-film thickness; 

• Liquid-film thickness; 

• Limestone reaction rate constant; 

• Limestone surface area factor; and 

• Solid solution rate constant. 

Reagent ratio was also input and adjusted for each of the cases during this 

calibration. 

D-2 
5. The system simulation model was then run with data from the other 

baseline tests. However, S02 removal results did not match the observed 

results because of differences in gas velocity. Iterative runs were then 

made for each case by adjusting the reagent ratio to achieve desired pH 

levels and then changing the gas-film thickness to reach the desired S02 

removal. The revised gas-film thickness results are shown in Figure D-1, 

with a straight line determined by regression analysis. The equation for the 

line is: 

Gas-film thickness (f.l) = -2.016 *(Gas velocity, ft/s) + 22 

6. All of the baseline and parametric test cases were then simulated using the 

gas-film thickness determined by the above equation. 

The final calibration parameters were: 

Input 

Gas-film thickness, microns (at 9ft/sec) 

Liquid-film thickness,% of droplet diameter 

Reaction rate constant 

Surface area factor 

Solid solution rate constant 

Value 

4.0 

0.06 

1.6e-5 

1.0 

3.0e-8 

Table D-1 compares predicted and observed results for the calibration cases and 

the remaining tests. The results of the calibration were very good with respect to agreement 

between predicted and observed S02 removal efficiency. The only case for which the predicted 

S02 removal was substantially different than the actual removal was Baseline Test 4 (58.7% 

predicted vs. 68.5% actual S02 removal). This particular data point lies well outside the range of 

interest for this project, though. For the remaining 17 cases, the average predicted S02 removal 

efficiency was less than 0.1 percentage points higher than the average observed removal with a 

standard deviation of only 1.1 so2 removal efficiency percentage points. 

The agreement between predicted and observed pH and limestone utilization, 

especially for the low-pH tests, was not as good as that for S02 removal. To match the observed 

D-3 
lOr-------------------------------------------~ 

8 

-

1:1'.) 

~ = a. 

u 

... 

e 6 -fl:l 

fl:l 

~ 

Ja 

u 

... 

.c 

Eo.; 

a 4 -... 

~ 

fl:l Para 10 

c = 

2 

3. 

0 

6 7 8 9 10 

Gas Velocity (ft/sec) 

Figure D-1. Kintigh FGDPRISM Calibration: 

Gas Film Correction 

D-4 
B-1 8.9 

B-2* 8.8 

B-3 9.8 

B-4 9.3 

B-5* 8.6 

B-6 9.3 

B-7 8.5 

B-8 6.2 

P-1 6.2 

P-2 8.3 

P-3 7.4 

P-4 8.1 

P-5 6.1 

P-6 8.1 

P-7 8.4 

P-8 8.4 

P-9 8.5 

P-10* 8.6 

TableD-1 

FGDPRISM Calibration Results 

Comparison of Observed and Predicted Performance 

4.05 5.54 5.60 84.0 85.3 

4.25 5.50 5.58 86.4 86.8 

2.23 5.55 5.59 84.1 86.6 

3.24 5.28 5.02 91.8 86.5 

4.65 5.28 5.18 90.0 88.5 

3.24 5.77 5.80 63.1 71.9 

4.85 5.75 5.81 63.2 71.4 

9.49 5.64 5.61 86.2 85.0 

9.49 5.61 5.63 89.3 89.7 

5.25 5.68 5.67 83.7 81.2 

7.07 5.62 5.64 86.3 86.3 

5.66 5.56 5.59 85.2 85.2 

9.69 5.86 5.83 79.8 79.3 

5.66 5.84 5.88 62.9 74.5 

5.05 5.12 5.13 94.0 79.6 

5.05 5.21 5.24 94.2 90.4 

4.85 5.49 5.54 88.9 86.9 

3.24 5.63 87.7 

* These tests used in calibration. 

D-5 

88.1 85.9 

93.8 92.0 

76.2 78.5 

58.7 68.5 

84.1 84.7 

88.7 88.2 

96.4 96.0 

96.3 96.5 

96.3 98.0 

98.6 98.5 

98.5 99.1 

96.8 96.6 

98.3 99.2 

96.5 97.4 

93.5 92.3 

98.0 96.6 

98.4 98.4 

99.9 99.5 
pH for the low-pH tests (Baseline Tests 4 and 5, Parametric Tests 7 and 8), FGDPRISM required 

that significantly higher limestone utilization be used as input than was actually measured in 

three of the four cases. Conversely, to match the tests at high pH (Baseline Tests 6 and 7, 

Parametric Tests 5 and 6), FGDPRISM required significantly lower utilization as input than was 

actually observed in three of the four cases. 

D-6 

APPENDIXE 

Detailed Economic Calculations 

E-1 

Table E-1 includes more detail with respect to the added costs of S02 removal for 

the cases shown in Table 4-2. Table E-1 also includes costs for additional options that were less 

cost-effective than those shown in Table 4-2. 

E-2 
Table E-1 

Economic Comparison of S02 Removal Upgrade Options 

5.6 0 85 85.0 0 0 0 0 o I 

5.6 0 85 88.0 2500 0 0 28000 57000 

trlll Close bypass I 5.8 0 85 96.8 9840 0 0 28000 326000' W (4pumps) 

Use finer~ Close bypass I 5.61 1000 I 851 97.81 10640 I 55000 I 30tooo I 28000 I I 245000 I 

(4 pumps) 

formate 

I 5.6 I 1250 I 85 I 96.7 I 9730 I 57000 I 372000 I 19000 I -152000 I 224000 I 

5.6 1000 85 94.8 8140 55000 292000 187000 

5.2 1250 89 95.4 8680 57000 367000 I 28000 117000 

5.8 750 72 97.9 10770 53000 226000 I 28000 586000 

o I 0 

43000 128000 

167000 521000 

181000 I 810000 

165000 I 685000 

138000 I 672000 

143000 I 712000 

199ooo 1 1092o0 

0 
t.r1 

.!.. 

Maintain current 

S02 removal, 

Finer grind 

(4 pumps) 

5.5 0 98 85.0 0 

Table E-1 

(Continued) 

0 

a Increased reagent cost includes $1 00,000/year for increased reagent preparation O&M. 

0 0 -116000" I -108000 I -224000