# Ammonia adsorption on ash

Prepared by Penelope Stamatakis

Introduction

There are two primary post combustion technologies that reduce NO

x 

### via the introduction of an

amine based reducing agent , namely Selective Non Catalytic Reduction (SNCR) and Selective

Catalytic Reduction (SCR). Ammonia slip is a by

- product of both of these technologies and it

refers to ammonia in the gaseous phase

, typically measured at the economizer outlet using EPA

meth od CTM

- 027 . The control of ammonia slip is an integral part of the optimization phase in

any SNCR or SCR application

. The gaseous ammonia left uncontrolled

, has the potential to

combine with SO 3 

### in the flue gas and form undesirable ammonium bisulfate deposits on metal

surfaces. Additionally, d epending on the ash properties, a significant amount of the ammonia slip

may be adsorbed on the ash. Typically, ammonia is adsorbed on the ash either chem ic ally

, via the

formation of ammonium sulfate and bisulfate salts on the ash

, or physi cally

, on unburned carbon

surfaces. This becomes a problem for clients who sell t heir ash to the cement industry, since

during the making of concrete

, a mmonia may be rele ased from the ash as the pH increases due to

the addition of lime. Released ammonia giv es off a unique odor which is detectable by smell if

the levels of ammonia on the fly ash exceed the range of 50 to 100 mg/kg

. Utilities that employ

Fuel Tech’s SNCR and SCR technologies routinely ask for the expected level of ammonia on the

fly ash. This study will address this question by looking at ammonia adsorption on the ash as a

function of coal type and ash properties and develop a methodology to predict ammo nia

adsorption on ash.

Background

During the combustion of sulfur

- containing fuels, over 95% of the sulfur is converted to sulfur

dioxide. Subsequently, more than 1% of the sulfur dioxide may be furthe r oxidized to sulfur

trioxide. (Ref. 1) Sulfur trioxide has the potential to combine with the ammonia slip generated via

the SNCR and SCR processes and form ammonium sulfate and ammonium bisulfate salts.

Ammonium bisulfate forms as a liquid which may deposit on cold metal surface s that are

maintained at temperatures below 360 o 

### F

. Ammonium sulfate is a powdery substance which

forms at temperatures below 410 o 

### F

. (Ref. 2) Both of these species can deposit on the fly ash.

Coal a s h with high cal cium content such as PRB ash exhibits high alkalinity and a s such it ha s a

low affinity for capturing ammonia. Eastern bituminous coal has a very low alkalinity ash which

acts as an ammonia sponge. Not all the gaseous ammonia, however, will adsorb on the ash

, since

a portion of the ammonia may also combine with SO 3 

### in the flue gas and form ammonium

bisulfate deposits on cold metal surfaces

. A study carried out by Southern Company using high S

coal suggests that about 30 % of the ammonia slip generated from an SNCR or SCR process

becomes tied up in ammonium sulfat e and bisulfate deposits on cold metal surface s while 70% is

available to the fly ash. (Ref. 3 ) Less than 1% of the ammonia slip will make it to the stack.

Clearly, the results of this analysis depend on the operating conditions during the study, but they

give an indication for the affinity of fly ash to ammonia when fuels with high S content are used

. A sh generated by PRB coal, which has high alkalinity, has low potential for ads or bing ammonia.

In addition , due to the low SO 3 

### concentration in the flue g as, ammonium sulfate and bisulfate

### formation will be fairly low as well , and as such, most of the ammonia slip will go up the stack.

This number is not known exactly, but this analysis will assume that a minimum of 7 0% of the

generated ammonia slip under PRB combustion will be released from the stack and only 30% will

be available for adsorption

. It is worth noting, however, that ammonia can still absorb on the

unburned carbon as demonstrated by Fuel Tech’s studies at Nipsco’s Bail l y #8

, even if the ash has

low affinity for the ammonia

. (Ref. 4 )

Many utilities sell their ash to the cement industry. Cement contains high quantities of lime, and

as it is hydrated to make concrete, its alkalinity increases. This high alkalinity causes the release

of ammonia from the concrete, and although it does not have any negative impact on the

properties of the concrete, it causes an odor which is unacceptable to both the concrete

manufacturer as well as the concrete end user. (Ref. 5 ) In general, the limits set by the cement

industry on the acceptable level of ammonia on ash are in the 50 to 100 mg/kg range . In order to

keep this concentration low, the ammonia in the gas phase needs to be limited in the 2 to 5 ppm

range.

In 1993, Fuel Tech briefly c onsidered the concept of thermally treating the ash to strip the

ammonia. During this time, preliminary analytical work showed a direct correlation between the

alkalinity of the ash and the amount of ammonia adsorbed. It was recognized, however, that mor e

and more utilities started burning PRB coal which generates ash that has low affinity for ammonia,

and the idea was abandoned. (Ref. 6)

Analysis

The flue gas flow generated by combustion can be calculated on the basis of the operating O 2 

### , the

amount of fuel burned, the higher heating value of the fuel, and the F d 

### factor which is fuel specific

and indicates the dry flue gas that is generated for every MMBtu of fuel burned as shown by the

equation below:

Flue gas(dscfh)= F d 

### (dscf/MMBtu)*HHV(Btu/lb)*10

- 6 

### MMBtu/Btu*Fuel( lb/hr)* 20.9/(20.9

- O 2 

### ) (1)

Ammonia slip generated in the gas phase is typically expressed in parts per million, ppm, and

represents the moles of ammonia per mole of flue gas multiplied by one million.

NH 3 

### slip (ppm) = [NH 3 

### (moles/hr)/Flue gas (moles/hr)]* 10 6 

### (2)

Since the molecular weight of NH3 is 17, the molar flow of ammonia can be calculated by

dividing the mass flow by 17. Similarly, the molar flow of the flue gas can be derive d by dividing

the volumetric flow by 385.4, where 385.4 comes from the ideal gas law and indicates the volume

of flue gas occupied by one mole of flue gas under standard conditions of temperature and

pressure. Equation (2) can therefore be rewritten as fol lows:

NH 3 

### slip (ppm) = [{NH 3 

### (lb/hr)/17 (lb/mol) }/{Flue gas (dscfh)/385.4 (dscf/mol)} ] * 10 6 

### (3)

Assuming a typical operating O 2 

### of 3% and combining equations (1) and (3), the maximum

ammonia generated in (lb/hr) is:

NH 3 

### (lb/hr) = NH 3 

### slip (p pm)*0.0515*F d 

### (dscf/MMBtu)*HHV (Btu/lb) *Fuel (lb/hr) (4)

The ammonia concentration on the ash is typically expressed on a gravimetric basis or ppm

- w.

This unit is equivalent to mg of ammonia/kg of ash or lb of ammonia /lb of ash divided b y a

million.

### NH 3 

### on ash (ppm

– w) = [NH 3 

### (lb/hr)/Ash (lb/hr)] * 10

- 6 

### (5)

Assuming that 80% of the ash becomes fly ash

, the above equation can be rewritten as follows:

NH 3 

### on ash (ppm

- w) = [NH 3 

### (lb/hr)/{%Ash*Fuel(lb/hr)*0.8}]*10

- 6 

### (6)

It should be noted that for cyclone fired units only 40% of the ash becomes fly ash while for wet

bottom units this number may be closer to 25%.

If all the ammonia slip is adsorbed on the ash and by combining equations 4 and 6, the maximum

concentration of ammonia on the ash would be:

NH 3 

### on ash (ppm

- w) , maximum = [ NH 3 

### slip(ppm)* 0. 0 644 * F d 

### * HHV /%Ash]*10

- 6 

### (7)

If an adsorption rate is established, then the ammonia on the ash of a specific coal can be

calculated as follows:

NH 3 

### on ash (ppm

- w) = Adsorption (%)* NH 3 

### on ash (ppm

- w), maximum or (8)

NH 3 

### on ash (ppm

- w) = Adsorption (%)* [NH 3 

### slip (ppm)* 0. 0 644 * F d 

### * HHV /%Ash]*10

- 6 

### (9)

EPRI has carried out several studies in an effort to investigate ammonia adsorption on fly ash for

various coals. Fuel Tech will utilize the measured ammonia on ash for each of the cases studied

by EPRI and will d etermine the % adsorption for each coal from the ratio of the measured amount

of adsorbed ammonia and the maxi mum amount of ammonia available for adsorption

.

The EPRI study focused on the ash collected from the following 8 sites (Ref. 7 ) :

TABLE I : Test sites

Utility Station Unit type Coal rank

Ameren Baldwin Cyclone Bit., hvC

Georgia Power Bowen #3 T

- fired Bit., hvB

AEP Cardinal I Wall fired Bit., hvB

SRI combustor Lone Mountain Wall fired Bit., hvA

Alabama Power Miller #3 Wall fired PRB

WEPCO Pleasant Prairie Wall fired PRB

Ameren Sioux I Cyclone PRB/Bit. hvC

Southern Power Stanton Wall fired Bit., hvA

The fly ash samples from each site were coll ected from various ESP hoppers. (Ref. 6) All the

samples from a specific site were blended together, and the analysis was done on this blended

sample. The ammonia adsorption on the fly ash was measured by Washington’s University in St.

Louis Air Quality Laboratory. The experiment consisted of exposing 1 gram of the blended fly

ash sample for 30 min to a flue gas consisting of 14% CO 2 

### , 4% O 2 

### , 10% H 2 

### O, 500 ppm SO 2 

### , 15

ppm of NH 3 

### and the balance was N 2. 

### The flue gas temperature was maintained at 325 o 

### F and the

flue gas flow was 500 accm. From the ammonia flow, flue gas volume, and the exposure time, it

was determined th at the maximum gravimetric amount of ammonia that could have been produced

is 0.106895 mg. If all this ammonia is adsorbed on the 1 g of fly ash, the maximum amount of

ammonia o n ash would be 106.9 mg/kg. The table below summarizes the actual amount of

ammonia adsorbed on the ash for all the applications as measured by the Air Quality Laboratory.

### In addition, it compares this value to the calculated value of 106.9 mg/kg and tak es the ratio. This

ratio shows the percent of ammonia actually adsorbed on the ash out of the amount that is

theoretically available for adsorption and is indicative of the potential for adsorption of ammonia

on fly ash for various fuels.

TABLE I I: Ammon ia Adsorption on Fly Ash

Fixed Exposure

Utility Station NH 3 

### Adsorbed

(mg/kg) NH 3 

### Adsorbed

(%)

Ameren Baldwin 92 86

Georgia Power Bowen #3 60 56

AEP Cardinal I 90 84

SRI combustor Lone

Mountain 128 100*

Alabama

Power Miller #3 15 14

WEPCO Pleasant

Prairie 16 15

Ameren Sioux I 81 76

Southern

Power Stanton 110 100*

The * d enotes that measured value was higher than what was theoretically available and for these

cases it was assumed that 100% of the ammonia was adsorbed. The above results show that the

ash from Miller and Pleasant Prairie exhibited the least amount of ammonia adsorption while fly

ash from Lone Mountain and Stanton Station exhibited the highest amount of ammonia adsorption

on the ash. It is worth noting that Miller and Pleasant Prairie burn PRB coal while lone Mountain

and Stanton burn high volatility bituminous A.

T he objective of this analysis is to be able to correlate the ads orption potential with specific

components of the fly ash or the fuel. Fuel Tech located the fuel analysis and ash analysis for the

above applications w ith the exception of Bowen #3. (Ref. 9 to 11 )

. Plant Bowen is not

specifically included in this discussion, although the general statement can be made that for this

bituminous, high volatility B coal, the rate of adsorption exceeds 50%. Finally, Sioux Station used

a blended coal, and t he ana lysis is based on an 83% Cabal l o and 17% Illinois #6 (2) coal.

TABLE I I I: Fuel analysis

Weight (%)

Moisture and

ash free Baldwin Cardinal Lone

Mountain Miller Pleasant

Prairie Sioux Stanton

C 78.9 84.1 87.84 74.8 74.94 75.6 83.27

H 5.5 5.6 5.43 5.37 5.27 5.3 5.53

O 10 4.96 4.23 18.4 18.34 1.14 8.4

N 1.38 1.53 1.58 0.96 1.07 1.13 1.6

S 4 3.86 0.93 0.46 0.38 1 1.08

HHV (Btu/lb) 12233 13859 15243 13032 14061 13750 13254

F d 

### (dscf/MMBtu) 11328 10755 10035 9661 8945 9305 10904

### The ash analysis for the above fuels is tabulated below:

TABLE IV : Fly ash composition

Constituents Baldwin Cardinal Lone

Mountain Miller Pleasant

Prairie Sioux

* Stanton

SiO2 (%) 48.91 39.65 55.83 27.8 31.9 34.79 58.2

Al2O3 (%) 18.26 19.68 28.67 13.1 16.9 17.13 30.67

Fe2O3 (%) 18.06 27.79 7.58 5.5 5.6 7.72 4.88

TiO2 (%) 0.88 0.85 1.29 1.3 1.4 1.31 2.08

CaO (%) 4.82 4.54 2.56 26.6 24.7 21.32 1.16

MgO (%) 1.04 0.85 1.64 7 4.6 3.99 0.42

Na2O (%) 1.03 0.9 1.0 1.3 1.4 1.34 0.17

K2O (%) 2.1 1.21 2.23 0.3 0.3 0.61 0.99

SO3 (%) 4.68 4.18 1.5 16 12.2 10.92 1.29

P2O5 (%) 0.21 0.34 0.37 1.1 1.0 0.87 0.133

The primary acidic components of fly ash are SiO 2 

### , Al 2 

### O 3 

### and TiO 2 

### while the basic components

are Fe 2 

### O 3 

### , CaO, MgO, Na 2 

### O and K 2 

### O. According to the ABB Combustion Fossil Power book, the

s um of the acidic components ranges between 20 and 90% while the sum of the basic components

ranges between 5 and 80%. The ratio of the sum of the basic components over the sum of the

acidic compo nents represents the Base/Acid (B/A) ratio of the ash.

B/A = [Fe 2 

### O 3 

### + CaO + MgO + Na 2 

### O + K 2 

### O]/[SiO 2 

### + Al 2 

### O 3 

### + TiO 2 

### ] (10)

The following table illustrates the B/A ratio of the ash for the applications of interest as a function

of lime and SO 3 

### content in the ash as well as the volatile S in the fuel. Ash with high B/A ratio

tends to have high CaO concentration which will react with t he volatile S and form CaSO 4 

### . The

SO 3 

### content in the fly ash actually represents the amount of S captured in the form of CaSO 4 

### . This

reaction neutralizes the S content of the fuel and minimizes the potential of the ammonia to be

adsorbed on the ash. The hypothesis, therefore, is that the higher the B/A ratio as well as the CaO

and SO 3 

### content of the ash, the higher the alkalinity of the ash, and the lower the potential for

ammonia adsorption on the ash. The B/A ratio is calculated for each application using the

information on Table IV along with equation (10). The ammonia adsorption on the ash is taken

from Table II and the r elationship of all these parameters is summarized in the table below:

TABLE V : Relationship between the ammonia adsorption on ash and the S content of the

fuel , as well as the B/A ratio, SO3 and CaO content of the ash

Baldwin Cardinal Lone

Mountain Miller Pleasant

Prairie Sioux Stanton

NH 3 

### adsorbed (%) 86 84 100 14 15 76 100

B/A 0. 42 0.586 0.175 0.964 0.729 0.653 0.084

S daf 

### (%) 4. 29 3.864 0.92 0.463 0.35 0.97 1.079

SO3 (%) 4. 70 4.183 1.5 16 24.7 10.922 1.292

CaO (%) 5.40 4.542 2.56 26.6 12.2 21.32 1.157

Ash (%) ,dry 10.77 9.4 7.5 5.85 7.3 5.3 6.9

This information is illustrated graphically in the following four plots.0.000 0.200 0.400 0.600 0.800 1.000 1.200

0.000 5.000 10.000 15.000 20.000 25.000 30.000

0 10 20 30 40 50 60 70 80 90 100 Base/Acid ratio CaO (%)

Adsorption rate of ammonia on ash (%) 

## Figure 1: Ammonia adsorbed on the ash as a function of ash

CaO and Base/Acid Ratio

Ash CaO content Base/Acid ratio

0.000 0.200 0.400 0.600 0.800 1.000 1.200

0.000 5.000 10.000 15.000 20.000 25.000 30.000

0 10 20 30 40 50 60 70 80 90 100 Base/Acid ratio CaO (%)

Adsorption rate of ammonia on ash (%) 

## Figure 2: Ammonia adsorbed on the ash as a function of ash

CaO and Base/Acid Ratio (Excludes Sioux)

Ash CaO content Base/Acid ratio0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 4.000 4.500

0.000 2.000 4.000 6.000 8.000 10.000 12.000 14.000 16.000 18.000

0 10 20 30 40 50 60 70 80 90 100 Sulfur content, daf (%) SO3 (%)

Adsorption rate of ammonia on ash (%) 

## Figure 3:Ammonia adsorbed on the ash as a function of ash

SO3 and fuel S content

Ash SO3 content Sulfur content (%)

0.000 0.500 1.000 1.500 2.000 2.500 3.000 3.500 4.000 4.500

0.000 2.000 4.000 6.000 8.000 10.000 12.000 14.000 16.000 18.000

0 10 20 30 40 50 60 70 80 90 100 Sulfur content, daf (%) SO3 (%)

Adsorption rate of ammonia on ash (%) 

## Figure 4: Ammonia adsorbed on the ash as a function of ash

SO3 and fuel S content (Excludes Sioux)

Ash SO3 content Sulfur content (%)

### Reviewing the above plots, it appears that in the case of the Sioux Station, which used the blended

PRB and bituminous coal, the properties of the bituminous coal overwhelmingly affect the

adsorption potential of the ash although the average Base/Acid rati o is high, and the CaO and SO3

concentrations are relatively high as well. The blended coal application introduce s a small amount

of scatter in the data, and consequently, Figures 2 and 4 should be the ones used in estimating the

adsorption potential of a ny given coal.

The se graphs show that the rate of ammonia adsorption on the ash is very low , less than 20%,

when the B/A ratio as well as the CaO and SO3 concentrations are high. On the other extreme, a s

the B/A r atio drops below 0. 1 5, the ammonia adsorption on the ash approaches almost 10 0%. In

general, the ammonia adsorption goes up if the S content is over 1%, however, the S content by

itself is not the best indicator of how high the ammonia adsorption rate will be and will need t o be

used in conjunction with the CaO and SO 3 

### concentrations.

Entering the information read from the pl ot s into Equation (9)

, the amount of ammonia adsorbed

on the ash may be estimated. This is an expected value , however, and is not intended for making

guarantees.

Working examples

The methodology for assessing the amount of ammonia adsorbed on fly ash is outlined below. The

analysis is done for three different coals, namely: Arclair, Antelope and San Miguel Lignite. It is

assumed that the amount of fly ash is 80% of the total ash and that the amount of ammonia slip

measured at the economizer outlet is 3 ppm. For the low S applications, it will be assumed that

30% of the ammonia slip will be available for adsorption while the rest will go out the stac k. For

the high S applications, it will be assumed that 70% of the ammonia slip will be available for

adsorption with the rest been tied up in the air heater.

Appendix 1 shows that Arclair has a B/A ratio of 0. 42 , an SO 3 

### content of 1 % and a CaO content of

4.2 %. A ppendix 2 shows that the S content of this fuel is 3. 4 6 % on a dry, ash free basis and the F d



### factor is 9 623 dscf/MMBtu. In addition, the ash content is 8.65 % and the Higher Heating

Value1 3149 Btu/lb on a dry basis

. Figure 2 illustrate s that for a coal with a B/A ratio of 0. 42

, t he

adsorption rate is about 70% while based on a CaO content of 4.2% , the ammonia adsorption

potential approaches 100 %. This high adsorption rate is further supported by the SO3 and S

concentration on Figure 4

. Consequently, by averaging out all these factors, the ammonia

adsorption on the ash for this particular coal is about 90%.

Applying the above adsorption rate in Equation (9) , and assuming that only 7 0% of the ammonia

slip will be available for adsorptio n , or just 2.1 ppm

, it is estimated that the ammonia adsorbed on

the ash in this application is 196 ppm

- w

. This is well above the 50 to 100 ppm

- w threshold for ash

sold to the cement industry. For the adsorbed ammonia to stay below this threshold, the NH 3 

### slip

will need to be maintained below 2 ppm which will severely limit the applicability of the SNCR

process and perhaps challenge the SCR process as well

.

For comparison purposes, the above analysis is repeated for Antelope coal under the same

condition s

. The B/A ratio from Appendix 1 is 0.77

, the CaO concentration is 23. 6 % and the SO3

concentration is10. 1 % . The fuel analysis in Appendix 2 shows that the S content is 0.35% on a

dry, ash free basis and an F d 

### factor of 9 852 dscf/MMBtu. T he ash content i s 7. 21 % and the

Higher Heating Value 9505 Btu/lb on a d ry basis. Using Figure 2 based a CaO concentration of

23. 6 % and a B/A ratio of 0.77 , the amount of ammonia adsorbed on the ash is expected to be

around 15 %. This is also consistent with the information in Figure 4 based on the S concentration

of 0.35% while based on the SO3 concentration the adsorption rate is closer to 30%. By averaging

out all these factors, the ammonia adsorption rate for this coal is about 20%. In addition, since this

### is a low S PRB coal, 7 0% of the ammonia slip is expected to be released from the stack and only

3 0% of the 3 ppm ammonia slip will be available for adsorption . Again, using Equation (9) for 0.9

ppm NH 3 

### slip available for adsor ption on the ash , the amount of ammonia adsorbed on the ash is

only about 1 5 ppm

- w. This suggests that even if the SNCR/SCR process operates at a relaxed

ammonia slip of 5 to 10 ppm, the 50 to 100 ppm

- w threshold of ammonia on ash is satisfied.

This is c onsistent with observations at the Boardman Station in Wyoming where Fuel Tech ran an

SNCR demonstration in 2009. Many fly ash samples were collected and analyzed and the average

amount of ammonia adsorbed on the ash at the different sections of the ESP w ere below 11.7

ppm

- w even when the ammonia dosage was as high as 21 ppm. This information is summarized

in Appendix 4.

Finally, the above exercise is repeated for San Miguel Lignite. Appendix 1 shows that San Miguel

Lignite has a B/A ratio of 0. 112 , an SO 3 

### concentration of 2. 9% and a CaO content of 3.0 %.

Appendix 2 shows that the S content of this fuel is 3. 66 % on a dry, ash free basis and the F d 

### factor

is 8665 dscf/MMBtu. In addition, the ash content is 36.3 % and the Higher Heating Value is 8446

Btu/ lb on a dry basis. Using Figure 2, it is determined that both on the basis of the CaO and the

B/A, the ammonia adsorption potential approaches 10 0%. This high adsorption rate is further

supported by the SO 3 

### an S concentration s on Figure 4

.

As in the case of the Arclair coal, since this is also a high S coal, it is assumed that 70% of the 3

ppm ammonia slip is available for adsorption or 2.1 ppm. Surprisingly, when the above adsorption

rate is used in Equation (9), it is estimated that the am monia adsorbed on the ash in this

application is only 2 7 ppm

- w

. This is a very low concentration and it is due to t he high ash

content of the fuel which dilutes the ammonia adsorption effect. Clearly, in cases like this, the

amount of ammonia on the ash is not the driving factor for limiting the ammonia slip but rather the

high potential for ammonium bisulfate fouling on the air heater surfaces

.

The above analysis has not taken into account the ammonia adsorbed due to unburned carbon. Based on

studies p erformed by Fuel Tech’s SCR group at Nipsco, it was determined that ammonia also adsorbs on

unburned carbon and the ammonia slip measurement is not a true measure of the ammonia sl ip generated

in the gaseous phase. The true ammonia slip will need to be ad justed by the % unburned carbon assuming

a 10% adsorption rate. Therefore, the higher the amount of unburned carbon, the higher the true ammonia

slip, the higher the amount of ammonia adsorbed on the ash.

Conclusions

1. For high S bituminous coals, about 70% of the generated ammonia slip is available for adsorption

on the ash. Approximately 30 % may react with SO 3 

### to form ammonium bisulfate and sulfate salts

which may deposit on cooler metal surfaces , and a very small portion is released from the sta ck.

2. For PRB coal, due to the low SO 3 

### concentration in the flue gas, a small portion of the ammonia

slip will participate in the formation of ammonium bisulfate and sulfate salts . In addition, due to

the high alkalinity of the ash, the potential for ammoni a adsorption on the ash is low, and it is

expected that the majority of the ammonia slip will be released from the stack. For the purposes

of this analysis, it has been assumed that 3 0% of the generated ammonia will be available for

adsorption

. 3. The potent ial of ammonia adsorption on the ash is great when the alkalinity of the ash is low as in

the case of bituminous fuels. Under these conditions 80 to 100% of the gaseous ammonia

available for adsorption on the ash may be adsorbed on the ash.

4. The potential of ammonia on the ash is low when the alkalinity of the ash is high as in the case of

PRB fuels. Under these conditions, only 10 to 2 0% of the gaseous ammonia available for

adsorption on the ash may adsorbed on the ash.

### 5. The B/A ratio, CaO and SO 3 

### concentr ation of the ash, as well as the %S content of the fuel are

good indicators in assessing the adsorption rate of ammonia on the ash.

6. The ash generated by a high S fuel may be very acidic if the CaO concentration is low and has the

potential to adsorb 100% o f the available ammonia. However, the actual concentration on the ash

may still be an acceptable value for the cement industry

, if this fuel has a very high ash

concentration.

7. The ash produced by the combustion of a PRB fuel has a very low potential for a dsorbing

ammonia. This potential, however, increases in the presence of unburned carbon.

References

1. Combustion Fossil Power, Windsor, Connecticut : Combustion Engineering, Inc., 1991

2. Air heater Fouling by Ammonia Bisulfate Deposition, Fuel tech Internal Report, March

1996

3. Lorimore L., Effects of Ammonia From Post Combustion NO

x 

### control on Ash Handling

and Use. , Fuel Chemistry Division Reprints, 2002

4. Discussions with Volker Rummenhohl internal to Fuel Tech

5. Homepage of W.S.Hinton and Associates, Fly Ash Behavior, www.wshinton.com

6. Handling of Ammonia in the Ash, Fuel Tech Internal Report, August 1993

7. Impacts of Ammonia Contamination of Fly Ash on Disposal and Use. EPRI Report

1004609, Octob er 2001

8. Investigation of Ammonia Adsorption on Fly Ash. EPRI Interim Report 112172, December

1998

9. Arch Coal, Inc. Fuel Analyses

10. Ash Chemistry, Ultimate Analyses and Heating Values of Various Coals

, www.et.byu.edu

11. Alstom Clean Combustion Technologies, Canada: Transcontinental printing, 2009

### Appendix 1

Fuel SiO2 Al2O3 Fe2O3 TiO2 CaO MgO Na2O K2O SO3 P2O5 B/A

Beulah Lignite 21.23 13.97 12.25 0.42 16.36 4.46 6.50 0.22 24.60 0.00 1.12

Arclair 48.08 18.59 20.60 0.99 4.22 0.88 0.54 2.23 0.99 0.00 0.42

Buckskin 30.76 13.51 5.85 1.03 24.78 5.71 1.59 0.23 15.1 1.44 0.84

Black Thunder 30.67 16.46 5.10 1.29 21.32 4.80 1.43 0.35 17.67 0.92 0.68

Antelope 31.74 15.71 5.96 1.25 23.75 5.65 1.64 0.54 10.11 1.72 0.77

SUFCO 5 2 .02 13.17 4.1 2 0. 81 13.28 3.83 2.28 1. 01 5.21 0. 46 0. 37

Elk Creek 53.94 23.57 6.5 8 0.99 3.94 1.41 1.76 1.59 1.76 1.01 0. 20

McElroy 48.17 21.91 21.57 0. 91 2.8 0.76 0.50 1.84 2.35 0. 39

Eastern Kentucky 58.20 30.67 4.88 2.08 1.16 0.42 0.17 0.99 1.29 0.13 0.08

Western Kentucky 51.06 18.41 19.56 0.99 3.04 1.14 0.63 2.88 2.02 0.12 0.39

Ohio #9 47.30 23.00 22.80 1.00 1.30 0.90 0. 30 2.00 1.2 0. 3 8

Bailey/Enlow Fork 47.14 23.02 21.17 0. 9 8 2.78 0.80 0.67 1.83 2.17 0. 38

Illinois #6 (2) 52.69 12.84 18. 77 0. 71 5.39 0.55 1. 45 1. 3 8 4. 72 0. 16 0.4 2

Kentucky #9 44.38 18.66 22.69 0.97 5.56 0.92 0.46 2.57 3.09 0. 4 4 0. 50

Pittsburgh #8 (1) 41.70 20.66 29.33 0.90 2.08 0.79 0.40 1.74 2.35 0.15 0.54

Pittsburgh #8 (2) 47.82 24.14 16.85 1.05 3.47 0.84 0.45 1.76 3.00 0.62 0.32

Pittsburgh #8 (3) 39.66 19.68 27.79 0.85 4.54 0.85 0.90 1.21 4.18 0.34 0.59

Pocahontas #3 37.92 24.16 17.14 1.14 7.67 2.40 0.83 1.84 6.79 0.10 0.47

Alicia 47.48 24.08 17.11 1.1 2 3.57 0.68 0.68 1.58 2.99 0. 33

San Miguel Lignite 66.79 19.69 1.69 0.88 3.04 0.49 2.63 1.91 2.86 0.01 0.11

Upper Freeport 51.53 24.35 13.46 0.92 2.48 1.30 0.30 3.07 2.43 0.14 0.27

Rochelle 34.10 17.00 5. 50 1.3 0 23.5 5.50 1.70 0.4 0 9.80 1. 20 0. 70

Central Appalachia 55.83 28.67 7.58 1.29 2.56 1.64 1.00 2.23 1.50 0.37 0.1 8

Belle Ayr 27.80 13.10 5.50 1.30 26.60 7.00 1.30 0.30 16.00 1.10 0.96

Cabal l o 31.90 16.90 5.60 1.40 24.70 4.60 1.40 0.30 12.20 1.00 0.73

Blend Caba llo& Illinois #6 (2) 35.34 16.21 7.84 1.28 21 .4 2 3.91 1. 41 0. 48 10.9 3 0.8 6 0.68

### Appendix 2

Fuel, dry ash free basis C

(%) H

(%) N

(%) S

(%) O

(%) HHV ,dry

(Btu/lb) %

H2O % ash,

d ry Fd

(dscf/MMBtu)

Beulah Lignite 70.49 4.75 1.22 2.14 21.36 7210 34.8 9.5 10533

Arclair 79.91 5.34 1.79 3.46 9.50 13419 9.33 8.65 9623

Buckskin 76. 26 5. 15 1.0 0 0.5 1 17.08 8979 30.86 5.1 9856

Black Thunder 74.73 5.40 1.00 0.51 18.27 9479 26.03 7.59 9833

Antelope 75.93 5.29 1.15 0.35 18.23 9505 26.5 7.21 9852

SUFCO 79.70 5.28 1.4 1 0. 45 13.15 1 2 146 10.13 12.1 9812

Elk Creek 77.97 5.3 9 1. 7 5 0.56 7.6 1 3651 6.71 10.7 9293

McElroy 80.30 5. 49 1. 66 3.76 8.76 1 4023 6.17 10.2 9447

Eastern Kentucky 84.00 5.5 0 1. 70 1.0 0 7.80 1 4 664 2.5 7.2 9691

Western Kentucky 79.00 5.60 1.7 0 3. 6 0 10.10 1 3223 8.3 12.2 9632

Ohio #9 80.70 5. 07 1. 32 3.73 8.33 1 3009 10.33 10.4 9678

Bailey/Enlow Fork 83.00 5.6 0 1. 75 2.29 7.10 1 4 038 6.32 8.06 9720

Illinois #6 (2) 78. 7 0 5. 50 1. 40 3.50 10.90 1 1773 18.3 7.59 9549

Kentucky #9 80. 10 5. 50 1. 70 4.70 8 .0 0 1 3700 6.1 11.9 9720

Pittsburgh #8 (1) 80. 90 5. 70 1. 50 2.50 10.90 13 092 8.7 9.3 9843

Pittsburgh #8 (2) 86.70 5.50 1. 8 1 1. 47 4.50 1 5012 2.6 9.34 9842

Pittsburgh #8 (3) 84.07 5.58 1.53 3.86 4.96 10755

Pocahontas #3 91.65 4.46 1.31 0.79 1.62 1 4390 4.4 7.4 10387

Alicia 83.60 5. 48 1.66 2.67 6.50 1 4237 5.96 8.6 9685

San Miguel Lignite 61.54 6.70 1.06 3.66 26.88 8446 32.49 36.3 8665

Upper Freeport 89.50 4.80 1. 50 1.30 2.90 1 2 372 1.1 8.58 12 312

Rochelle 74. 90 5. 15 1.07 0. 31 19.20 1 2566 2.73 6.3 9663

Central Appalachia 87.84 5.43 1.58 0.92 4.23 1 4252 6.5 7.5 10035

Belle Ayr 74.78 5.37 0.96 0.46 18.38 9148 29.8 6.55 9661

Caba l lo 74.94 5.27 1.07 0.38 18.34 8927 29.9 8.7 9876

Blend Caba l lo & Illinois #6 (2) 75. 5 8 5.3 1 1.1 5 0.91 17.08 9384 27.9 8.5 9 814

### Appendix 3

Fuel B/A S (%),

daf CaO (%) SO3 (%) Application similar

to %NH3

adsorbed

Beulah Lignite 1.12 2.14 16.4 24.6

Arclair 0.42 3.46 4.2 1.0

Buckskin 0.84 0.5 1 24. 8 15.1

Black Thunder 0.68 0.51 21.3 17.7

Antelope 0.77 0.35 23.8 10.1

SUFCO 0. 37 0. 45 13.3 5.2

Elk Creek 0. 20 0.56 3.9 1.8

McElroy 0. 39 3.76 2.8 2.4

Eastern Kentucky 0.08 1.0 0 1.2 1.3 Stanton 100

Western Kentucky 0.39 3. 6 0 3.0 2.0

Ohio #9 0. 3 8 3.73 1.3 1.2

Kentucky #9 ) 0. 38 2.29 2.8 2.2

Illinois #6 (2) 0.4 2 3.50 5.4 4.7 Baldwin 86

Kentucky #9 0. 50 4.70 5. 6 3. 1

Pittsburgh #8 (1) 0.54 2.50 2.1 2.3

Pittsburgh #8 (2) 0.32 1. 47 3.5 3.0

Pittsburgh #8 (3) 0.59 3.86 4.5 4.2 Cardinal 84

Pocahontas #3 0.47 0.79 7.7 6.8

Alicia 0. 33 2.67 3.6 3.0

San Miguel Lignite 0.11 3.66 3.0 2.9

Upper Freeport 0.27 1.30 2.5 2.4

Rochelle 0. 70 0.31 23.5 9.8

Central Appalachia 0.18 0.92 2.6 1.5 Lone Mountain 100

Belle Ayr 0.96 0.46 26.6 16.0 Miller 14

Caba l lo 0.73 0.3 8 24.7 12.2 Pleasant Prairie 15

Blend Cabal l o and Illinois #6 (2) 0.6 8 0.91 21.4 10.9 Sioux 76

### Appendix 4

REPORT OF FLY ASH

Title of the Project: Boardman Ammonia Testing During SNCR Trials Date Received: 08

- Dec

- 09

Contact Person: Pam Flynn Tested By: KC

Project Number: 5257 Report Date: 16

- Dec

- 09

Boral Sample ID Operations Details Sample Description NH 3 (ppm NH 3 in FA)

91208012 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 A 3.7

91208013 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 C 5.6

91208014 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 D 9.5

91208015 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 E 10.8

91208016 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 F 13.7

91208017 10 PPM dose rate. Boiler under normal conditions 1 2/4 Row 31 G 15.5

91208018 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 H 11.7

91208019 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 J 3.8

91208020 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 K 3.5

91208021 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 L 3.2

91208022 10 PPM dose rate. Boiler under normal conditions 12/4 Row 31 M 3.0

91208023 10 PPM dose rate. Boiler under normal conditions 12/4 Ro w 32 A 7.2

91208024 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 B 2.8

91208025 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 C 8.5

91208026 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 D 6.3

91208027 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 E 17.3

91208028 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 F 13.5

91208029 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 G 11 .7

91208030 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 H 21.2

91208031 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 J 13.8

91208032 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 K 6.7

91208033 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 L 4.6

91208034 10 PPM dose rate. Boiler under normal conditions 12/4 Row 32 M 2.9

91208035 10 PPM dose rate. Boiler under normal conditions 12/4 Row 35 COMPOSI TE 7.7

91208036 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 A 3.0

91208037 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 C 4.3

91208038 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 D 10.3

91208039 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 E 22.6

91208040 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 F 21.9

91208041 21 PPM dose rate. Boiler set to mimic lo w NOx conditions 12/6 Row 31 G 14.7

91208042 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 H 18.5

91208043 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 J 9.3

91208044 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 K 5.0

91208045 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 L 4.6

91208046 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 31 M 3.2

91208047 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 A 6.1

91208048 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 B 3.8

91208049 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 C 8.8

9120805 0 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 D 5.2

91208051 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 E 17.3

91208052 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 F 22.5

91208053 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 G 9.5

91208054 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 H 22.6

91208055 21 PPM dose rate. Boiler set to mimic low N Ox conditions 12/6 Row 32 J 3.1

91208056 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 K 7.7

91208057 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 L 4.8

91208058 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 32 M 4.2

91208059 21 PPM dose rate. Boiler set to mimic low NOx conditions 12/6 Row 35 COMPOSITE 11.7

45 NE LOOP 410, SUITE 700 SAN ANTONIO, TEXAS (210) 349

- 4069