Defining Material Maximum Potential Emission Calculations

Use the Process Unit Material Emission Calculations form to specify how you want to calculate the maximum potential emission rates from each material emitted at a source during an activity. As opposed to your actual emissions, maximum potential emissions are based on physical limitations of equipment and maximum operating parameters, so their values are essentially fixed.

Note: This form can only be accessed through the Process Unit Maximum Potential Emission Model form.

For instruction on defining material maximum potential emission calculations, click the following links or use the scroll bar to scan the page.

Overview of Material Emission Calculations for Maximum Potential Emission Models
Using an Emission Equation to Calculate Maximum Potential Material Emissions
Specifying an Emission Rate for Maximum Potential Material Emissions

Overview of Material Emission Calculations for Max Potential Emission Models

The table below provides important information about how the selections made and information entered on the Process Unit Material Emission Calculations form affect calculations.

Calculation Requirements	Considerations
Material emitted and the type of emissions generated	Select a material emitted at the source, and then specify the type of emissions that are generated, such as air. If you need to calculate more than one type of emissions from the same material, such as both air and water emissions, you must enter the calculations separately.
Equation	To calculate a material's maximum potential emissions, you can select an emission equation or specify a steady emission rate. If you plan to select an emission equation, first verify that the equation is up-to-date using the Equation Editor form. Once you select the equation and save, the variables that comprise the equation will appear in the sections. For any global constants and system variables, the system will automatically reference the correct value based on how the variables were defined in the equation. You need only enter maximum values for any equation constants, global emission factors, and parameters. Parameters are those that you monitor for the source, such as throughput. If you choose to specify a steady emission rate, enter the value in the Equation Constants section and select the appropriate unit of measure, such as pounds per hour.
Speciation method for a mixture	You have several options for speciating a mixture into its individual components, including the option not to speciate it at all. Standard speciation—the emission rates for the individual components of the mixture are displayed after you calculate emissions instead of the emission rate for the entire mixture. Selective speciation—allows you to speciate out only certain components of a mixture, such as only those components that contribute to VOC emissions. To use this option, you need to also select a speciation group that contains the materials to speciate out from the mixture. Any components that are not in the speciation group will be ignored. Use Vapor, Liquid, or Solid Concentration—If you choose one of these speciation options, the VLE calculations to derive the vapor compositions of the material's components will not be performed. Instead, each component's vapor composition will be set to one of the concentration values entered in the Material Composition and Properties section on the Material form. Refer to Speciation Method Emission Rate Determination and VLE Molecular Weight Speciation Configuration for additional information.
Vapor pressure basis	When the "Material's vapor pressure methods" option is specified, the vapor pressure of a pure material or mixture is determined using the method selected in the Material Composition and Properties section on the Material form. For the "Component's vapor pressure methods" option, Raoult's Law will be used (mixtures only).
Basis of Estimate	Select a TRI Basis of Estimate for TRI reporting and/or an Other Basis of Estimate for non-TRI reporting (such as state emissions inventory reporting). Just determination methods assigned a TRI/SARA code/classification will be available for selection as a TRI Basis of Estimate. Accordingly, just determination methods without a TRI/SARA code/classification will be available for selection as an Other Basis of Estimate.
Process unit link	Identify the process unit to which the generated emissions are directed, such as a control device or waste disposal system. (The list will only contain those process units that you designated on the Process Unit Link form as receiving generated streams from the source.) If the material is released directly into the atmosphere, you do not have to specify a process unit link.

Using an Emission Equation to Calculate Max Potential Material Emissions

Specify an equation and enter the maximum values for the equation constants, parameters, and global emission factors on the Process Unit Material Emission Calculation form. This form can only be accessed through the Process Unit Maximum Potential Emission Model form.

To specify an emission equation

Click Data Entry > Emission Model Information > Process Unit Max Potential Models in the Navigation Tree.

The Process Unit Max Potential Models list appears.
Locate the emission model, click the link to display the Process Unit Maximum Potential Emission Model form, and expand the Material Emissions section when necessary.
Click Material Calculations to display the Process Unit Material Emission Calculations form.

For identification and tracking purposes, the Show Record Details icon is displayed next to the Material field.
Select a Material from the list.

If the material is not listed, click the Ellipsis button and add it.
Select an Output Type, Equation and Estimation Quality Rating from the list for each field.

If the appropriate value is not listed, click the Ellipsis button next to the field and add it.
Select a Speciation Type from the list when entering a mixture, along with a different MW Physical Property and a Second MW Physical Property when applicable.

Tip: The MW physical property fields are displayed only when the Speciation Type is Standard Speciation or Selective Speciation. For additional information about speciation, refer to Speciation Method Emission Rate Determination and VLE Molecular Weight Speciation Configuration.
Select a Speciated Group from the list when the Selective Speciation value has been chosen.

If the speciated group is not listed, click the Ellipsis button and add it.
Select a Vapor Pressure value.
Select a TRI Basis of Estimate for TRI reporting and/or an Other Basis of Estimate for non-TRI reporting (such as state emissions inventory reporting) from the list for each field.

If the appropriate basis of estimate is not listed, click the Ellipsis button and add it.
Select a Process Unit Link from the list when the emission model source directs its emissions to another process unit.
Click the Save button on the form.

Applicable expressions are listed in the Equation Details section. Any global constants and system variables are displayed in the Global Constants and System Variables sections.
Expand the Equation Constants section when necessary and follow these guidelines for each parameter:
1. Click the Edit button adjacent to the line item.
2. Select a Units of measure, enter a Value, and click Save. The information specified is added to the line item in the Equation Constants section.
Expand the Parameters-Maximum Values section when necessary and follow these guidelines for each parameter:
1. Click the Edit button adjacent to the line item.
2. Select a Units of measure, enter a Value, and click Save. The information specified is added to the line item in the Parameters-Maximum Values section.
Expand the Global Emission Factors section when necessary and follow these guidelines for each global emission factor:
1. Click the Edit button adjacent to the line item.
2. Select a Units of measure, enter a Value, and click Save. The information specified is added to the line item in the Global Emission Factors section.
Click the Save button on the form, then click Close.

The material emission information is displayed as a line item in the Material Emissions section on the Process Unit Maximum Potential Emission Model form. Edit existing material emission information using the button adjacent to the line item.

Specifying an Emission Rate for Max Potential Material Emissions

Define an emission rate for max potential material emissions in the Equation Constants section on the Process Unit Material Emission Calculation form. This form can only be accessed through the Process Unit Maximum Potential Emission Model form.

To specify an emission rate

Click Data Entry > Emission Model Information > Process Unit Max Potential Models in the Navigation Tree.

The Process Unit Max Potential Models list appears.
Locate the emission model, click the link to display the Process Unit Maximum Potential Emission Model form, and expand the Material Emissions section when necessary.
Click Material Calculations to display the Process Unit Material Emission Calculations form.
Select a Material from the list.

If the material is not listed, click the Ellipsis button and add it.
Select an Output Type and Equation from the list for each field.

If the appropriate value is not listed, click the Ellipsis button next to the field and add it.
Select a Speciation Type from the list when entering a mixture, along with a different MW Physical Property and a Second MW Physical Property when applicable.

Tip: The MW physical property fields are displayed only when the Speciation Type is Standard Speciation or Selective Speciation. For additional information about speciation, refer to Speciation Method Emission Rate Determination and VLE Molecular Weight Speciation Configuration.
Select a Speciated Group from the list when the Selective Speciation value has been chosen.

If the speciated group is not listed, click the Ellipsis button and add it.
Select a Vapor Pressure value and Base of Estimate from the list for each field.

If the appropriate base of estimate is not listed, click the Ellipsis button and add it.
Select a Process Unit Link from the list when the emission model source directs its emissions to another process unit.
Click the Save button on the form.

Any global constants and system variables are displayed in the Global Constants and System Variables sections.
Expand the Equation Constants section when necessary and follow these guidelines for each equation constant:
1. Click the Edit button adjacent to the line item.
2. Select a Units of measure, enter a Value, and click Save. The information specified is added to the line item in the Equation Constants section.
Click the Save button on the form, then click Close.

The material emission information is displayed as a line item in the Material Emissions section on the Process Unit Maximum Potential Emission Model form. Edit existing material emission information using the buttons adjacent to the line item.