Although no specific PM/PM10 emission limits are established in the NSPS for combustion turbines, BACT must be considered for the control of particulate.
Step 1: Identify Potential Control Technologies
The first step in the BACT analysis is to identify all potential control technologies available for the control of PM/PM10 emissions. The technologies identified for the control of PM/PM10 emissions are as follows:
- Electrostatic precipitation (ESP)
- Fabric filter
- Good combustion practices
- Fuel specification: clean burning fuels
Step 2: Eliminate Technically Infeasible Options
The second step in the BACT analysis is to eliminate any technically infeasible control technologies. Each control technology for each pollutant is considered, and those that are clearly technically infeasible are eliminated. The following is a list of control options deemed technically infeasible for the control of PM/PM10 emissions.
Electrostatic Precipitators
ESP technology removes particulate from an exhaust stream by electrically charging the particles and collecting the charged particles on plates. ESP performance is greatly affected by the particles’ ability to accept and maintain an electrical charge. Because of the resistivity of gas turbine exhaust particles, ESP technology is ineffective for the control of PM/PM10 emitted from the proposed PSE (Puget Sound Energy) turbine.
Electrostatic precipitators are also not considered technically feasible options for combustion turbines due to the high exhaust flow rate and the low concentration of particulate in the turbine exhaust.
Fabric Filters
Fabric filters remove PM/PM10 from an exhaust stream by collecting the particulate on the filter as the air stream passes through the filter. Fabric filters typically cannot withstand high exhaust temperatures (>500 °F) and would be damaged by the high temperature of turbine exhaust. Thus, fabric filters are not technically feasible for the proposed PSE turbine.
Step 3: Ranking of Remaining Control Technologies by Control Effectiveness
The third step in the BACT analysis is to rank the remaining control technologies in order of control effectiveness. Table 6.19 presents the control technologies and their approximate control efficiencies.
Step 4: Evaluation of the Most Effective Emissions Controls
Because ESP technology and fabric filters have been deemed technically infeasible, the implementation of good combustion practices and the firing of clean burning fuels are the only remaining options for the control of PM/PM10 emissions. The combination of implementing good combustion practices and the firing of clean burning fuels is the most effective emission control option.
Step 5: Select BACT for the Control of PM/PM10 Emissions
Properly tuned burners firing natural gas and light oils inherently emit low levels of particulate matter. The RBLC database indicates that good combustion control is widely accepted as BACT for turbines firing natural gas. Thus, it is selected to use of clean burning fuels (natural gas and fuel oil with a sulfur content <0.05%) and good combustion practices as BACT for PM/PM10 emissions.
Table 6.19 Ranking of feasible control technologies by effectiveness.
| Pollutant | Control technology | Potential control efficiency (%) |
| PM/PM10 | Good combustion practices | Base case |
| Fuel specification: clean burning fuels | Base case |
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