The data and calculation methodologies found herein are based on those outlined in Appendix F of Title 40 CFR Part 75 in the US EPA's Acid Rain Program, and support recommendations relating to the EPA's Mandatory Greenhouse Gas Reporting (Tier 4 approach) and the World Resources Institute Greenhouse Gas Protocol.
Following these methodologies, this category includes functionality for specifying the flow rate of stack emissions, the concentrations of CO2, O2 and moisture within the stack outflow, and the duration of facility operation. The concentration of O2 within the stack outflow is useful for deriving a corresponding CO2 concentration where this is not explicitly available.
Using this category
To use this category, select the type of fuel burned using the fuel and subtype drill choices. Next specify the stack average volumetric gas flow, the stack CO2 concentration and the duration of facility operation using the flowRate (volume per time), carbonDioxideConcentration (fraction, 0-1) and operatingTime (time) profile item values. The returned value represents the CO2 emitted during the operating time specified, converted into kilograms using the default CO2 density of 0.0517104 kg per scf.
Specifying CO2 density
The default value for CO2 density can be over-ridden by setting the density profile item value. This may be useful if density data specific to the atmospheric conditions of the facility stack are available.
Specifying stack moisture content
If CO2 concentration is measured on a dry basis (i.e. stack moisture is removed prior to the analysis), the emissions calculation must include a correction for stack gas moisture content so that the volumetric concentration matches the volumetric flow basis. To specify the moisture content of the stack emissions, set the moistureContent profile item value (fraction, 0-1). CarbonKit will take this moisture level into consideration, following EPA guidelines, when calculating total CO2 emissions.
Specifying stack O2 concentration
If direct stack CO2 concentration data is not available, it can be back-calculated using O2 concentration data. To specify the O2 concentration, set the value (fraction, 0-1) using the oxygenConcentration profile item value. CarbonKit will derive the corresponding CO2 concentration according to the EPA methodology, and return the quantity of CO2 emissions associated with the flow rate and operating time specified. Users should note that the O2 based calculation is only used if no CO2 concentration is explicitly specified in the carbonDioxideConcentration profile item value. As with the direct CO2 calculation, any specified moisture content will be taken in to account.
See here for information on using British thermal units (Btu's) with the CarbonKit platform