### Name: Steve Mills

Title: Designated Representative Company: Public Service Company of Colorado Sign Date: 8/31/2010 Name: Patrick Clark Title: Owner Company: Airtech Environmental Services Sign Date: 8/31/2010 Permitted Facility Representative / Date Testing Company Representative / Date 

## Arapahoe Unit 4 2010 HAP ICR

Final Test Report for

/ / Based on information and belief formed after reasonable inquiry, I certify that the statements and information in this test report are true, accurate, and complete. I have reviewed all testing details and results in this test report and hereby certify that the test report is authentic and accurate.

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### Arapahoe Unit 4 2010 HAP ICR 8/31/2010 Facility Information: Arapahoe 2601 South Platte River Drive

Denver CO 80223 Contact: Chad Campbell Phone: 303-294-2111 Fax: 303-294-2859 Email: chad.campbell@xcelenergy.com Testing Company: Airtech Environmental Services, Inc. 5776 Lamar Street

Arvada CO 80002 Contact: Patrick Clark Phone: 303-670-0530 Fax: 303-670-4130 Email: pclark@airtechenv.com

Air Permit Number: 96OPDE136 Permitted Source ID/Name: Unit 4 Boiler 4 Permitted Maximum Process Rate: Max. Normal Operation Process Rate: Target Process Test Rate

Description of the source (including control equipment). Please see the attachments for source or process flow diagram: Arapahoe Station Unit 4 is a top fired boiler with underfired air. The unit is equipped with a dry sorbent injection system (uses Trona) to control SO2 emissions and an FFDC to control PM emissions. The unit typically fires PRB subbituminous coal.

The following describes any modifications and/or deviations to the applicable test methods. If alternative methods were requested, see the attachments for documentation of request AND approval, including dates. Per discussion with Peter Westlin on January 22, 2010, a three point traverse was approved since there are no Industry/SCC/NAIS 221112

Sampling Location Information:

Test Parameter Information: AFS #: 031.0008.004 FRS #: 110000467129

SCC / Description 10100222 External Combustion Boilers - Electric Generation - Bituminous/Subbituminous Coal - Pulverized Coal: Dry Bottom (Subbituminous Coal)

The following state and federal regulations that apply to the proposed testing:

Location Round

Duct Diam. Distance from upstream dist. Distance from

downstream dist. Number of

Traverse Ports Equiv. Diam Min.Travers Points Rect. Duct Length /Width Duct 0 432 288 1 143.9 3 96 287.5

Target Parameter Test Method Number of

Test Runs Test Run

Duration Sample

Points Comments Location Hydrogen Fluoride Method 26A 4 180 0 Duct Hydrogen Chloride Method 26A 4 180 0 Duct



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### Arapahoe Unit 4 2010 HAP ICR 8/31/2010 entrained water droplets in the flue gas. Sampling was conducted at a constant rate of 0.75 cfm and utilized the Method 26 impingers.



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### Arapahoe Unit 4 2010 HAP ICR 8/31/2010

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### Arapahoe Unit 4 2010 HAP ICR 8/31/2010 Sampling / Stack Data Results Summary 

### Location Duct - Method 26A Average Run Number 1 2 3 Test Date 6/17/2010 6/17/2010 7/22/2010 Run Start Time 9:40:00 AM 1:12:00 PM 9:55:00 AM Run Finish Time 12:43:00 PM 4:15:00 PM 1:08:00 PM Net Run Time, minutes Dry Gas Meter Volume Sampled, dscf 106.121 105.131 105.170 105.474 Moisture Content of Stack Gas, % 11.54 11.84 13.29 12.223 Moisture Saturation at Stack Gas Temperature, % 100.00 100.00 100.00 100.000 Carbon Dioxide, % 12.1 11.9 12.4 12.133 Oxygen, % 5.9 6.2 6.9 6.333 Average Stack Gas Temperature, °F 321.56 324.11 323.56 323.077 Dry Volumetric Flow Rate, dry scfm 254,070.7 251,371.6 228,019.1 244,487.133 Actual Wet Volumetric Flue Gas Flow Rate, acfm 515,200.9 513,130.9 474,835.8 501,055.867 Percent Isokinetic of Sampling Rate, % F-Factor, dscfm/MMBtu @ %O2 9574 9622 9644 9,613.333 Fw 0 0 0 0.000 Fc 0 0 0 0.000



### Location Duct - Method 26A 3 Average Run Number Test Date Run Start Time Run Finish Time Net Run Time, minutes Dry Gas Meter Volume Sampled, dscf Moisture Content of Stack Gas, % Moisture Saturation at Stack Gas Temperature, % Carbon Dioxide, % Oxygen, % Average Stack Gas Temperature, °F Dry Volumetric Flow Rate, dry scfm Actual Wet Volumetric Flue Gas Flow Rate, acfm Percent Isokinetic of Sampling Rate, % F-Factor, dscfm/MMBtu @ %O2 Fw Fc



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### Arapahoe Unit 4 2010 HAP ICR 8/31/2010

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### Arapahoe Unit 4 2010 HAP ICR 8/31/2010 Emissions Summary

Process Run Data 

### Location: Duct - Method 26A Compound: Hydrogen Chloride Average RunNumber 1 2 3 Mass_mg 80.77 5.256 1.027 29.018 lb/mmBtuO2 2.24E-02 1.51E-03 3.10E-04 0.008 

### Compound: Hydrogen Fluoride Average RunNumber 1 2 3 Mass_mg 1.253 3.166 1.917 2.112 lb/mmBtuO2 3.47E-04 9.08E-04 5.79E-04 0.001


### Location: Duct - Method 26A 3 Compound: Hydrogen Chloride Average RunNumber 4 Mass_mg 1.4605 1.461 lb/mmBtuO2 3.99E-04 0.000 

### Compound: Hydrogen Fluoride Average RunNumber 4 Mass_mg 2.362 2.362 lb/mmBtuO2 6.46E-04 0.001



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### Arapahoe Unit 4 2010 HAP ICR 8/31/2010 Process Run Data

APCD Run Data

Process Lab Run Data 

### Run Name Value UOM Comments Target Value 1 Gross Load 110.71 MW 0 

### 1 Heat Input 1400 MMBTU/HR 0 1 Main Steam Flow 898.89 KPPH 0 1 Flue Gas Flow Rate 21013 KWSCFH 0 

### 1 DSI Injection Rate 45 % 0 2 Gross Load 110.22 MW 0 2 Heat Input 1397.8 MMBTU/HR 0 

### 2 Main Steam Flow 899.29 KPPH 0 2 Flue Gas Flow Rate 20813 KWSCFH 0 2 DSI Injection Rate 45 % 0 

### 3 Gross Load 104.99 MW 0 3 Heat Input 1357 MMBTU/HR 0 3 Main Steam Flow 860 KPPH 0 

### 3 Flue Gas Flow Rate 19737 KWSCFH 0 3 DSI Injection Rate 20 % 0 1 Heat Input 1400 Million Btus/million BTU using CO2 0 

### 4 Gross Load 104.82 MW 0 4 Heat Input 1349.0 MMBTU/HR 0 4 Main Steam Flow 860 KPPH 0 

### 4 Flue Gas Flow Rate 19728 KWSCFH 0 4 DSI Injection Rate 20 % 0 4 Heat Input 1349.0 Million Btus/million BTU using CO2 0

Run Name Value UOM Comments Target Value 

### 1 OVERFIRE AIR 0 0 1 DRY SORBENT INJECTION 0 0 

### 1 BAGHOUSE 0 0

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### Arapahoe Unit 4 2010 HAP ICR 8/31/2010 Sampling / Stack Data Results Detail 

### Location Duct - Method 26A Average Run Number 1 2 3 Test Date 6/17/2010 6/17/2010 7/22/2010 Run Start Time 9:40:00 AM 1:12:00 PM 9:55:00 AM Run Finish Time 12:43:00 PM 4:15:00 PM 1:08:00 PM Net Traversing Points 18 18 18 Net Run Time, minutes Nozzle Diameter, inches Pitot Tube Coefficient 0.84 0.84 0.84 0.840 Dry Gas Meter Calibration Factor 1.0045 1.0045 1.0018 1.004 Barometric Pressure, inches of Mercury 24.6 24.6 24.5 24.567 Average Orifice Meter Differential, inches H2O 1.40 1.40 1.43 1.410 Dry Gas Meter Volume Sampled, cubic feet 135.000 135.000 135.360 135.120 Average Dry Gas Meter Temperature, °F 97.06 102.31 99.86 99.743 Dry Gas Meter Volume Sampled, dscf 106.121 105.131 105.170 105.474 Total Moisture Liquid collected, g 294 300 342.4 312.133 Volume of Water Vapor, standard cubic feet 13.84 14.12 16.12 14.693 Moisture Content of Stack Gas, % 11.54 11.84 13.29 12.223 Moisture Saturation at Stack Gas Temperature, % 100.00 100.00 100.00 100.000 Dry Mole Fraction 0.8846 0.8816 0.8671 0.878 Carbon Dioxide, % 12.1 11.9 12.4 12.133 Oxygen, % 5.9 6.2 6.9 6.333 Carbon Monoxide & Nitrogen, % 82 81.9 80.7 81.533 Fuel Factor 1.24 1.24 1.13 Dry Molecular Weight, lb/lb-Mole 30.17 30.15 30.26 30.193 Wet Molecular weight, lb/lb-Mole 28.77 28.71 28.63 28.703 Flue Gas Static Pressure, inches of H2O 1.2 1.2 1.2 1.200 Absolute Flue Gas Pressure, inches of Mercury 24.69 24.69 24.59 24.657 Average Stack Gas Temperature, °F 321.56 324.11 323.56 323.077 Average Velocity Head, inches of H2O 0.3537134945 6549 0.348940049

25354 0.297037882

951681 0.333 Average Stack Gas Velocity, feet/second 44.80 44.62 41.29 43.570 Stack Cross-Sectional Area, square feet 191.667 191.667 191.667 191.667 Dry Volumetric Flow Rate, dry scfm 254,070.7 251,371.6 228,019.1 244,487.133 Actual Wet Volumetric Flue Gas Flow Rate, acfm 515,200.9 513,130.9 474,835.8 501,055.867 Percent Isokinetic of Sampling Rate, % Percent Excess Air, % 37.5 40.2 47.9 41.867 F-Factor, dscfm/MMBtu @ %O2 9574 9622 9644 9,613.333 Round Duct Diameter, inches 0 0 0 Rectangular Duct Width, inches 96 96 96 Rectangular Duct Length, inches 287.5 287.5 287.5 Fw 0 0 0 0.000 Fc 0 0 0 0.000



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### Arapahoe Unit 4 2010 HAP ICR 8/31/2010 Location Duct - Method 26A 3 Average Run Number Test Date Run Start Time Run Finish Time Net Traversing Points Net Run Time, minutes Nozzle Diameter, inches Pitot Tube Coefficient Dry Gas Meter Calibration Factor Barometric Pressure, inches of Mercury Average Orifice Meter Differential, inches H2O Dry Gas Meter Volume Sampled, cubic feet Average Dry Gas Meter Temperature, °F Dry Gas Meter Volume Sampled, dscf Total Moisture Liquid collected, g Volume of Water Vapor, standard cubic feet Moisture Content of Stack Gas, % Moisture Saturation at Stack Gas Temperature, % Dry Mole Fraction Carbon Dioxide, % Oxygen, % Carbon Monoxide & Nitrogen, % Fuel Factor Dry Molecular Weight, lb/lb-Mole Wet Molecular weight, lb/lb-Mole Flue Gas Static Pressure, inches of H2O Absolute Flue Gas Pressure, inches of Mercury Average Stack Gas Temperature, °F Average Velocity Head, inches of H2O Average Stack Gas Velocity, feet/second Stack Cross-Sectional Area, square feet Dry Volumetric Flow Rate, dry scfm Actual Wet Volumetric Flue Gas Flow Rate, acfm Percent Isokinetic of Sampling Rate, % Percent Excess Air, % F-Factor, dscfm/MMBtu @ %O2 Round Duct Diameter, inches Rectangular Duct Width, inches Rectangular Duct Length, inches Fw Fc



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