2 | February 23, 2010 ICAPCD RULE 400.2 APPENDIX B Section E of the rule includes monitoring and recordkeeping to insure compliance. New and existing emission Units that do not require modification to comply with the rule shall be in full compliance upon adoption of the rule. However, for existing sources not in compliance with Rule 400.2 limits, a c ompliance schedule, incorporated in section I, allows sources to ease into compliance at a later date. The compliance schedule for units that require equipment modification is as follows:

 By June 30 , 20 10 , submit a complete application for an Authority t o Construct for all

modifications to non

- exempted emission units.

 By June 30, 2011, be in full compliance with the requirements of the rule.

II BACKGROUND

Boilers or Steam Generators are closed vessels in which water is heated and where steam is generated or superheated, or any combination thereof, under pressure or vacuum by the application of heat from the combustion of fuels. Process heaters are closed vessels where heat is transferred to fluids, process stream or other material. Boilers, steam generat ors and process heaters have no direct contact between the products of combustion and the material to be heated.

NOx forms during the combustion of fuel, and other products of combustion are emitted to the atmosphere in the flue gas stream. The formation of NOx resulting from the combustion processes is governed primarily by the chemically

- bound nitrogen content of the fuel, the oxygen concentration of the flame, the temperature of the flame, and the length of time the combustion gases are held at the fla me temperature.

III CONTROL TECHNOLOGIES

For most applications reducing NOx emissions from boilers, steam generators and process heaters can be broken down into four methods. These are: (1) retrofit low NOx emitting burners, (2) retrofit flue gas recirculat ion systems (3) installation of ammonia or urea injection systems for selective noncatalytic reduction, and (4) installation of ammonia or urea injection systems along with catalytic reactors for selective catalytic

reduction.3 | February 23, 2010 ICAPCD RULE 400.2 APPENDIX B A Low NOx Burners

Low NOx bu rners employ low excess air combustion, air staging, fuel staging or combustion product recirculation to lower NOx formation in the flame. Low excess air combustion and combustion product recirculation decrease the oxygen available for

NOx formation. Com bustion product recirculation also lowers the bulk flame temperature, and consequently lowers the NOx formation rate and equilibrium concentration. Staged air burners lower available oxygen at points in the combustion chamber where the temperature is high . Staged fuel burners lower the temperature at points in the combustion chamber where available oxygen is high. Installation of low NOx burners on existing units may require derating of equipment, because flame lengths may be significantly increased.

Lo w NOx burners are applicable to most gas fired and oil fired units. For gas fired units, the control effectiveness ranges from 10 to 55 percent. For units fired with conventional fuel oils or crude oil the anticipated reduction will be lower due to the e ffects of chemically bound nitrogen in the fuel. It is likely that Low NOx burners using staged combustion and O2 control can achieve the gas

- fire standards contained in the rule. However, it is anticipated most liquid fuel fired units will require low n itrogen content "clean fuels" and Low NOx burners and other controls to comply with the emission limitation of the proposed rule.

B Flue Gas Recirculation (FGR)

FGR for NOx control consists of extracting a portion of the flue gas from the economizer outlet and returning it to the furnace, admitting the flue gas through the furnace windbox. Flue gas recirculation lowers the bulk furnace gas temperature and reduces

oxygen con centration in the combustion zone. A retrofit installation of FGR consists of adding a fan, duct work, dampers, and controls as well as possibly having to increase existing fan horsepower due to increased draft loss. FGR is an effective control technique for gas fired units, but FGR is not effective at reducing NOx formation originating from fuel

- bound nitrogen. The control effectiveness of flue gas recirculation ranges from 60 to 70 percent for gas fired units. For units fired with conventional fuel

oil s or crude oil the anticipated reduction will be lower due to the effects of chemically bound nitrogen in the fuel.

C Selective Catalytic Reduction (SCR)

SCR is a process that chemically reduces NOx with ammonia (NH 3 ) over a heterogeneous catalyst in the presence of oxygen (O 2 ). The process is termed selective because the reducing agent ammonia (NH 3 ) preferentially attacks NOx rather

than O 2 . However, the O 2 enhances the reaction and is a necessary part of the reaction scheme. Thus, SCR is potentially a pplicable to flue gas under oxidizing conditions, greater than one percent O 2

.4 | February 23, 2010 ICAPCD RULE 400.2 APPENDIX B SCR retrofit requires a reactor, which contains the catalytic material, and an ammonia storage and injection system. Due to the increased pressure drop across the reactor,

som e increase in boiler fan horsepower, or possibly a new fan may be necessary.

D Selective Non

- Catalytic Reduction (SNCR)

SNCR processes for NOx control have been developed by several companies using ammonia and urea as reagents. These non

- catalytic reducti on processes are based on the gas phase homogeneous reaction between NOx in the flue gas and the reagents utilized by the process.

In general, ammonia (NH 3 ) or urea based reagent is injected into the hot flue gas by means of either air or steam carrier ga s at a point in the flue specifically selected to provide optimum reaction temperature and residence time. In the temperature range of

1600 **°** F to 2200 **°** F, the reaction occurs through the injection of these reagents. Hydrogen can also be injected along with ammonia to extend the effectiveness range of

the DeNOx reaction down to 1300 **°** F.

NOx reductions of up to 90 percent have been demonstrated on an oil field steam generator where favorable process conditions exist. The SNCR performance using

earlier techno logy ranges from 50 to 70 percent reduction for most oil fired and gas fired process heaters and steam boilers.

IV EMISSIONS REDUCTIONS FOR RULE 400.2

The ICAPCD staff conducted a survey of the permit database to identify the number of boilers, steam genera tors, and process heaters which will need to be replaced or retrofitted to comply with the new RACT requirements. The retrofitting of the emission units will fructify in a reduction of the emissions inventory for the facilities. Approximately 13 units rated 5 million Btu per hour or greater are operated at three of Imperial County’s major source facilities and will be affected by the requirements of Rule 400.2.

The ICAPCD survey indicates that one of the boilers (Unit 4) operated by Imperial Irrigation District at the El Centro Generating Facility would be out of compliance with

the new emission limits. Unit 4 is currently equipped with a SCR and the source has been committed to restrict operation of this unit and to com ply with the limits under the alternative compliance schedule ; this boiler operates irregularly throughout the year and fuel usage will be limited to a maximum of 30 % . A second boiler (Unit 3) operated at this facility will be shutdown and replaced with a re

- powering project which will be in full compliance with BACT standards. Spreckels Sugar Company has indicated that its natural gas boilers will be retrofitted with Flue Gas Recirculation technology . In addition, one of natural gas process heaters oper ated by US Gypsum will be retrofitted to low Nox Burner in order to comply with RACT standards. The ICAPCD survey has not identified any existing boilers or process heaters operated at minor sources that may be out of compliance with the proposed RACT stan dards.5 | February 23, 2010 ICAPCD RULE 400.2 APPENDIX B Summarized results of the average estimated NOx emissions reductions in lbs/year and tons/year are given in Table 1. The average emission reductions for IID and US Gypsum emissions units are derived from an average of three years of results extracted from source tests submitted to ICAPCD by each company. In the case of Spreckels Sugar information only two years of sou rce test data is available ; therefore

, the average emission reductions are an average of two years of results extracted from source tests submitted to ICAPCD by Spreckels Sugar.

Table 1 Summary NOx Emissions

Reductions Estimated for Rule 400.2 Limits

F acility

Name Emission

Unit Average Yearly

Reductions

(lbs/year) Average Yearly

Reductions (Tons/year)

IID Boiler

No. 4 253,447 126.7

Holly Sugar CE

Boiler 16,565 8.3

Holly Sugar Union

Boiler 826 0.4

Holly Sugar Auxiliary

Boiler 123 0.1

U.S. Gypsum Line # 1

Stack 1 3,772 1.9

U.S. Gypsum Line # 1

Stack 2 3,877 1.9

U.S. Gypsum Line # 1

Stack 3 8,049 4.0

TOTAL 286,659 143.3

The average NOx emissions reductions for each emissions unit listed on Table 1 are calculated in the following tables.6 | February 23, 2010 ICAPCD RULE 400.2 APPENDIX B Imperial Irrigation District Boiler No. 4 (3 Year Average)
Facility

Name Emission

Unit Total

MMBtu Curren
t ppmv Current

Emissions (lb/year) New

ppmv New

Emissions (lbs/year) Reductions (lbs/year)

3% O2

IID Boiler No. 4 (year 2008) 2,662,1

45 129 525,500 70 225,787 299,713

IID Boiler No. 4 (year 2007) 1,692,3

05 149 336,600 70 143,531 193,069

IID Boiler No. 4 (year 2006) 2,143,9

95 126 449,400 70 181,841 267,559

IID Boiler No. 4 Average Reduction Per Year 253,447

Spreckels Sugar Company, Inc

- CE Boiler (3 Year Average)
Facility

Name Emission

Unit Total

MMBtu Current

ppmv Current

Emissions (lb/year) New

ppmv New

Emissions (lbs/year) Reductions (lbs/year)

3% O2

Sprecke ls Sugar CE Boiler (year 2007) 410,36

7 100 49,721 70 34,805 14,916

Spreckels Sugar CE Boiler (year 2002) 385,45

3 109 50,906 70 32,692 18,214

Spreckels Sugar CE Boiler Average Reduction per Year (2 year Avg.) 16,565

Note: Only Source test data for 2007 & 2002 are available7 | February 23, 2010 ICAPCD RULE 400.2 APPENDIX B Spreckels Sugar Company, Inc

- Union Boiler (*2 Year Average)
Facility

Name Emission

Unit Total

MMBt

u Current

ppmv Current

Emissions (lb/year) New

ppmv New

Emissions (lbs/year) Reductions (lbs/year)

3% O2

Sprecke ls Sugar Union

Boiler (year 2007) 64,08

0 66 5,124 70 5,435

- 311

Spreckels Sugar Union

Boiler (year 2002) 95,24

7 87 10,040 70 8,078 1,962

Spreckels Sugar Union Boiler Average Reduction per Year (2 year Avg.) 826

Note: Only Source test data for 2007 & 2002 are available

Spreckels Sugar Company, Inc

- Auxiliary Boiler (3 Year Average)
Facility

Name Emission

Unit Total

MMB

tu Current

ppmv Current

Emissions (lb/year) New

ppmv New

Emissions (lbs/year) Reductions (lbs/year)

3% O2

Spreckels Sugar Auxiliary

Boiler (year 2006) 17,98

4 75 1,634 70 1,525 109

Spreckels Sugar Auxiliary

Boiler (year 2005) 22,46

7 75 2,042 70 1,906 136

Spreckels Sugar Auxiliary Boiler Average Reduction per Year (2 year Avg.) 123

Note: 75 ppmv value was used from 2008 source test results8 | February 23, 2010 ICAPCD RULE 400.2 APPENDIX B U.S. Gypsum

- Line #1 (Stack #1) (3 Year Average)
Facility

Name Emission

Unit Total

MMBtu Current

ppmv Current

Emissions (lb/year) New

ppmv New

Emissions (lbs/year) Reductions (lbs/year)

3% O 2

U.S. Gypsum Stack #1 (Year 2008) 8,402 63 641 30 305 336

U.S. Gypsum Stack #1 (Year 2007) 31,729 80 3,075 30 1,153 1,922

U.S. Gypsum Stack #1 (Year 2006) 276,896 57 19,123 30 10,065 9,058

U.S. Gypsum Stack #1 No Reduction per year (3 year Avg.) 3,772

U.S. Gypsum

- Line #1 (Stack #2) (3 Year Average)
Facility

Name Emission

Unit Total

MMBtu Current

ppmv Current

Emissions (lb/year) New

ppmv New

Emissions (lbs/year) Reductions (lbs/year)

3% O 2

U.S. Gypsum Stack #2 (Year 2008) 52,863 60 3,843 30 1,922 1,921

U.S. Gypsum Stack #2 (Year 2007) 130,874 75 11,893 30 4,757 7,136

U.S. Gypsum Stack #2 (Year 2006) 88,566 54 5,795 30 3,219 2,575

U.S. Gypsum Stack #2 No Reduction per year (3 year Avg.) 3,8779 | February 23, 2010 ICAPCD RULE 400.2 APPENDIX B U.S. Gypsum

- Line #1 (Stack #3) (3 Year Average)
Facility

Name Emission

Unit Total

MMBtu Current

ppmv Current

Emissions (lb/year) New

ppmv New

Emissions (lbs/year) Reductions (lbs/year)

3% O 2

U.S. Gypsum Stack #3 (Year 2008) 135,905 66 10,868 30 4,940 5,928

U.S. Gypsum Stack #3 (Year 2007) 282,397 68 23,267 30 10,265 13,002

U.S. Gypsum Stack #3 (Year 2006) 143,538 60 10,435 30 5,217 5,217

U.S. Gypsum Stack #3 No Reduction per year (3 year Avg.) 8,049