HERC NAAQS Report December 2010 AECOM Environment Ii
Total Page：16
File Type：pdf, Size：1020Kb
Environment Submitted to: Submitted by: Covanta Hennepin Energy Resource Company AECOM Minneapolis, MN Westford, MA 60144287 December 2010 National Ambient Air Quality Standard Modeling for the Capacity Optimization Project Hennepin Energy Resource Company Minneapolis, Minnesota Environment Submitted to: Submitted by: Covanta Hennepin Energy Resource Company AECOM Minneapolis, MN Westford, MA 60144287 December 2010 National Ambient Air Quality Standard Modeling for the Capacity Optimization Project Hennepin Energy Resource Company Minneapolis, Minnesota _________________________________ Prepared By Carlos Szembek ________________________________ Reviewed By David W. Heinold, CCM AECOM Environment i Contents 1.0 Introduction ...................................................................................................................... 1-1 1.1 Project Overview ................................................................................................................. 1-1 1.2 Report Organization ............................................................................................................ 1-1 2.0 Source Characterization ................................................................................................. 2-1 2.1 Facility Overview ................................................................................................................. 2-1 2.2 Emission Estimates ............................................................................................................. 2-1 2.2.1 MSW Combustion Units ....................................................................................... 2-1 2.2.2 Lime, Carbon, and Ash Silos ............................................................................... 2-2 2.2.3 Plant Roads .......................................................................................................... 2-2 2.2.4 Cooling Towers ..................................................................................................... 2-2 2.3 Source Parameters ............................................................................................................. 2-2 3.0 Air Dispersion Modeling Methodology ......................................................................... 3-2 3.1 Overview of Analysis Methodology ..................................................................................... 3-2 3.2 Building Downwash ............................................................................................................. 3-2 3.3 Dispersion Environment ...................................................................................................... 3-2 3.4 Terrain Considerations ........................................................................................................ 3-2 3.5 Meteorological Data ............................................................................................................ 3-3 3.6 Receptor Data and Processing ........................................................................................... 3-3 3.7 Model Options for 1-hr NO2 ................................................................................................. 3-4 3.8 Model Options for all other Criteria Pollutants .................................................................... 3-7 4.0 Ambient Air Quality Analysis Results ........................................................................... 4-1 4.1 Overview of Modeling Analysis ........................................................................................... 4-1 4.2 1-hour NO2 Model Analysis ................................................................................................. 4-1 4.3 Other Criteria Pollutant Model Analysis .............................................................................. 4-2 HERC NAAQS Report December 2010 AECOM Environment ii List of Tables Table 2-1 Combustion Units Stack Parameters ................................................................................ 2-1 Table 2-2 Ancillary Units Stack Parameters ..................................................................................... 2-1 Table 3-1 Representative Ambient Background Data ....................................................................... 3-7 Table 3-2 Flagpole Receptors ............................................................................................................ 3-1 List of Figures Figure 2-1 Facility Location ................................................................................................................. 2-1 Figure 3-1 Buildings Included in Downwash Analysis (near-field view) Showing Building Height (distances in meters).......................................................................................................... 3-1 Figure 3-2 3km Area Surrounding the HERC Facility ........................................................................ 3-2 Figure 3-3 50km Polar Grid ................................................................................................................. 3-3 Figure 3-4 Location of the Flagpole Receptors. (Flagpole labels reference the ID numbers in Table 3- 2) ......................................................................................................................................... 3-4 Figure 3-5 Location of MPCA NO2 and O3 Monitors .......................................................................... 3-5 Table 4-1 Modeling Results ............................................................................................................... 4-1 List of Appendices Appendix A Emissions Estimation Spreadsheets Appendix B GEP Analysis Appendix C AECOM’s POST-1HR Fortran Code Appendix D Stack Measurements of NO and NO2 at Covanta Lee HERC NAAQS Report December 2010 AECOM Environment 1-1 1.0 Introduction 1.1 Project Overview The Hennepin Energy Resource Center (HERC) facility is a mass-burn municipal waste combustor with a design combustion capacity of 1,212 tons per day of municipal solid waste in two identical combustion units. Steam produced from combustion is used to turn a 39-megawatt turbine/generator. The facility sells approximately 35 megawatts of electricity (the power usage of approximately 26,000 single family homes) to Xcel Energy. The HERC facility has operated continuously since startup in October 1989. The facility was designed and built by Blount Projects and includes the following major equipment for combustion and air emissions control: two excess-air grate-fired waterwall furnaces, two dry scrubbers for acid gas neutralization, a reverse-air fabric filter baghouse to capture particulates, select non-catalytic reduction of nitrogen oxides, and an activated carbon injection system for capture of gaseous mercury. The HERC facility is owned by Hennepin County and operated by Covanta Hennepin Energy Resource Company, LP. (CHERC) CHERC is proposing to remove the state-only annual limit on fuel usage of 365,000 tons per year and allow the facility to process MSW at its maximum capacity of 442,380 tons per year. The purpose of this modeling analysis is to demonstrate that HERC facility with the proposed change in annually permitted fuel use will comply with National Ambient Air Quality Standards (NAAQS). 1.2 Report Organization The modeling report consists of the following sections and appendices: Section 2 - Source Description and Emissions Section 3- Dispersion Modeling Methodology Section 4- Ambient Air Quality Impact Methods and Results Appendix A Emissions Estimation Spreadsheets Appendix B GEP Analysis HERC NAAQS Report December 2010 AECOM Environment 2-1 2.0 Source Characterization 2.1 Facility Overview The HERC facility is a mass-burn municipal waste combustor with a design combustion capacity of 1,212 tons per day of municipal solid waste in two identical combustion units. Steam produced from combustion is used to turn a 39-megawatt turbine/generator. The facility includes the following major equipment for combustion and air emissions control: two excess-air grate-fired waterwall furnaces, two dry scrubbers for acid gas neutralization, a reverse-air fabric filter baghouse to capture particulates, select non-catalytic reduction of nitrogen oxides, and an activated carbon injection system for capture of gaseous mercury. The location of the HERC facility is shown in Figure 2-1. 2.2 Emission Estimates The following paragraphs discuss the method used to calculate emissions for each emission unit. 2.2.1 MSW Combustion Units The exhaust flow rate is directly proportional to the steam flow rate. The original design steam flow rate for the HERC is 171,380 pounds of steam per hour. The exhaust flow rate corresponding to that steam flow rate was calculated using actual stack test data from 2008 and 2009. During those stack tests, both exhaust flow rate and steam flow rate were measured. These stack tests were chosen because they were conducted at a short term fuel use rate of greater than 50.5 tons per hour. Using the stack test data, the design exhaust flow rate was calculated to be 63,735 dry standard cubic feet of exhaust at 7% oxygen content (dscfm @ 7% O2)per combustion unit. The design exhaust flow rate was used to calculate the annual average hourly emission rates. In accordance with the provisions of New Source Performance Standard Subpart Cb, the maximum steam flow rate allowed at HERC is 195,000 pounds of steam per hour. Using the exhaust flow rate to steam flow rate ratio the short term maximum allowable exhaust flow rate was