Environmental Controls and Emissions Management
Domain focus
This domain tests air-pollutant formation, control equipment, monitoring, and permit compliance. Expect NOx, SO2, particulate, CO, mercury, CEMS, and corrected gas conditions.
Core rules
- NOx forms from thermal fixation, fuel nitrogen, and prompt mechanisms; low-NOx burners, overfire air, SCR, and SNCR reduce it.
- SO2 is controlled by fuel switching, flue-gas desulfurization, or sorbent injection.
- Particulate is captured by ESPs or baghouses; opacity is a surrogate, not a mass measurement.
- CEMS data must be quality-assured and corrected to standard conditions and a specified O2 basis.
- Permits set limits, monitoring, recordkeeping, and reporting; exceedance triggers notification and corrective action.
Worked example
An ESP inlet dust loading is 4.0 gr/dscf and outlet is 0.04 gr/dscf. Collection efficiency = (4.0 − 0.04)/4.0 × 100 = 99.0%. The reasoning: efficiency is the fraction removed, not the outlet concentration alone. If the permit limit is 0.05 gr/dscf, the outlet passes; if the inlet rises to 6.0 gr/dscf at the same efficiency, outlet becomes 0.06 gr/dscf and exceeds the limit.
Traps
Comparing ppm and lb/MMBtu without conversion; ignoring O2 correction; treating opacity as mass; and using CEMS data without QA. Also check whether limits are hourly, daily, or rolling average.