Читать книгу Continuous Emission Monitoring - James A. Jahnke - Страница 33

Forty‐two source categories, ranging from stationary fuel combustion sources to electronics manufacturing, emitting more than 25 000 metric tons of CO_2e per year are required as per 40 CFR 98 to report greenhouse gas emissions. Monitoring methods are specified in each of the 42 subparts; however, sources subject to Part 75 where CO₂ monitors are already installed must use CEM system data for reporting. Hazardous waste incinerators with installed CO₂ monitors must similarly report emissions using CEM system data. However, for most source categories, the reporting rule does not require the installation of continuous emission monitors, but allows the use of production data and emission factors instead.

Subpart C of Part 98 applies to stationary sources that combust fossil fuels. Here, a tier approach is taken, where each successive tier requires more measurements and the application of fewer emission factors, with the assumption that the higher the number of the tier, the higher the accuracy of the reported data. As an example of the use of emission factors, in Tiers 1 and 2, CO₂ emissions are calculated from the following equation:

(2‐3)

where

 CO2 = annual CO2 mass emissions (metric tons) for a particular type of fuel

 Fuel = quantity of fuel combusted during the year (tons, scf, gal)

 HHVd = default (Tier 1) or measured (Tier 2) high heating value of fuel (mmBtu per quantity of fuel)

 EF = fuel‐specific default CO2 emission factor (kg CO2/mmBtu)

Tier 3 applies to sources larger than 250 mmBtu that have not been required to install a CEM system. In this tier, sources are required to monitor fuel use and the carbon content of the fuel instead of the fuel’s high heating value. CEM systems are used for Tier 4 reporting, where annual emissions are calculated as a pollutant mass rate times operating time. Methane and nitrous oxide emissions are reported using default emission factors for CH₄ and N₂O in Equation 2‐3. The CH₄ and N₂O calculate emissions data are combined with the CO₂ data to report greenhouse gas emissions as CO_2e, carbon dioxide equivalents.

Greenhouse gas issues and reporting procedures are discussed in greater detail in Chapter 14.