In the Essential Air module, you can model the sources in operation at your entity using real-time data and complex emission equations. You can set up emission models to calculate actual and maximum potential emissions from a source and copy these models from one process unit to another.
For instruction on modeling source operations, click the following links or use the scroll bar to scan the page.
Defining Maximum Potential Emission Model Process Conditions |
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Viewing Maximum Potential Emission Model Material Information |
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Emission models describe how to calculate the actual and maximum potential emissions from sources engaged in a specific activity, such as coating application or pulp refining. You might produce a product or perform a process in one or more different ways, such as with control devices turned on or off. Therefore, within each emission model, you must also specify one or more scenarios to accommodate these diverse operating conditions.
It is recommended that you establish general emission models and scenarios that describe an activity instead of setting up process unit-specific emission models. For example, you should establish an emission model that describes the emissions from producing tape instead of ones that describe the emissions from each individual part of the tape production—feeding, coating, and curing. You can then assign the same general emission model and scenario to all the process units involved in the activity.
The reason for setting up general emission models is that when scheduling production at your entity, you select the emission models and scenarios that are active during the date range, not the individual process units. Therefore, if you assign the same emission model and scenario to all the process units that are involved in an activity, the emissions from all of these process units will be evaluated in the calculations. You will be assured you have not inadvertently left a process unit out of the production schedule.
It is also important to realize that if an activity can occur under different operating conditions (alternate scenarios), you must assign that alternate scenario to all of the process units involved in the activity. This condition applies even if not all process units are operating under the alternate scenario. For instance, suppose during tape production, the control device abating emissions from the coating process unit is turned off. This would indicate a different operating condition for that particular process unit. However, all the other process units are operating under the same conditions. You would also be required to assign the alternate scenario to the other process units in the activity if you elect to use general emission models to schedule the process unit operation.
In addition to actual emission models, you can also define maximum potential emission models. These models detail the source’s maximum potential to emit during the activity. You should use the same emission model and scenario names to model both actual and maximum potential emissions.
If, in addition to abating emissions, a control device also generates emissions, you should define an emission model for it in the same way as your other sources. Use the following forms in the order specified to model the emissions from a source:
On the Emission Model form, establish the names of the emission models. You can use the same models for both actual and maximum potential emissions.
On the Emission Model Scenario form, associate one or more operating scenarios with each emission model.
On the Process Unit Emission Model form, assign an emission model and scenario to a source, and then enter the modeling conditions.
On the Process Unit Maximum Potential Emission Model form, assign an emission model and scenario to a source, and then enter the maximum potential modeling conditions.
On the Process Unit Emission Model form, you can set up emission models that describe the behavior of your sources during an activity. An activity could be a process that the source is involved in, such as applying coating, or the production of a product, such as tape. During these activities, the source will generate certain emissions from pollutant materials.
In the emission model, you specify what the process conditions are at the source, what individual materials or class of materials are emitted, and where these emissions are directed. To indicate how the emissions from each pollutant material should be calculated, you must select an equation.
Emission models can also compensate for different operating conditions during an activity through the use of scenarios. For instance, during startup, a boiler may operate under non-ideal conditions. Therefore, the boiler will generate different emissions than when it is operating normally and under optimal conditions. To indicate the two varied conditions under which it can operate, the boiler can reference different emission model scenarios.
You can also use scenarios to store outdated methods of performing calculations that you must maintain for historical reporting and recordkeeping. When you are scheduling production, the effective and shutdown dates are used for determining which emission model and scenario to reference.
To establish emission models
Click Data
Entry > Emission Model Information > Process Unit Emission Models
in the Navigation Tree.
The Process Unit Emission Models
list appears.
Click the New
button.
The Process Unit Emission Model
form is displayed.
Select an Entity
from the list.
Tip: The lookup tool next to the Process
Unit field can be used to select an entity/process unit combination.
Select a Process Unit from the list. Just the process units designated as a Source and assigned Air module access in the Type section on the Process Unit form are available for selection.
Select a Model
name and Scenario name from
the list for each field. (Only scenarios that were associated with
the selected model will be listed.)
If the appropriate value is not listed, click the Ellipsis
button next to the field and add it.
Enter an Effective Date and Shutdown Date for the model, or click the Calendar button and select the date. If the shutdown date is left blank, the model will always be effective.
Select a GHG Scope when applicable.
Expand the Model Description section and add text that identifies the model.
Add information in the General Emission Information, Material Emissions, Material Group Emissions, and User Defined Properties sections.
Click the Save button on the form.
Repeat steps 2 through 10 to add other emission models.
In the General Emission Information section on the Process Unit Emission Model form, enter process condition information for a source's activity.
The emission stream temperature is the vapor stream temperature to be used in vapor-liquid equilibrium (VLE) calculations. This value is also used as the inlet temperature if the process unit is connected to a control device where the condenser equation is used to model its abatement.
For speciation vapor pressure calculations, two options that are used to determine temperature are available:
A fixed emission temperature and unit of measure. An entry in both the Emission Temperature and Unit fields is required for this option to be used to speciate.
A parameter result temperature for a user-specified parameter, subject to the following conditions:
The Essential Air calculator uses the latest parameter result that exists at the same date and time as the production schedule Start Date. The "time" value = hour/minute/second/millisecond. If the temperature value is missing from this result or a result record does not exist, a warning message is provided.
Just entity parameters, production unit parameters, and process unit parameters with a "Temperature" Unit Type can be specified, i.e., the Base Unit field on the Parameter validation form contains an F.
Parameters with material qualifiers can be specified; however, the material qualifier information is not used in emissions calculations. The parameter specified (with or without a material qualifier) is used to determine temperature in speciation vapor pressure calculations only.
The parameter must be active at the time the emission model becomes effective. A parameter inactive date is entered in the General section on the Parameter Definition form.
For this option to be used to speciate, the Use a Parameter-entered Emission Temperature check box must be selected and a value must be chosen for the Parameter Type (level) field and the Emission Temperature Parameter Name field (and Material Qualifier field if applicable). In addition, if you select the Production parameter type, a Production Unit must also be specified.
If you are modeling a tank and use an inert gas as a padding, you can select the noncondensable material used and enter the system pressure. For example, nitrogen gas is often used in tanks. Only materials whose vapor pressure method was marked as "Noncondensable" in the Material Composition and Properties section on the Material form will be available.
You can also document the following for each model:
Production Material—used to relate the activity occurring within the model to the production of a specific material. This information is used for recordkeeping only.
SARA Exempt—used to exclude the source from emission inventories and SARA reports. In this way, you can model a "what if" scenario to determine the impact of increased production on emission limits.
GHG MRR Exempt—used to exclude the emissions calculated for the emission model from GHG mandatory reporting of greenhouse gases.
To establish emission model
process conditions
Locate the emission model on the Process Unit Emission Models list, click the link to display the Process Unit Emission Model form, and expand the General Emission Information section when necessary.
Select the Use a Parameter-entered Emission Temperature check box when applicable. Otherwise, skip to step 4.
Select the Parameter
Type (level), Emission Temperature
Parameter Name, and Material
Qualifier (if applicable) from the list for each field. When
the Production parameter
type is selected, the Production
Unit field is displayed. Select a production unit first and
then choose the emission temperature parameter name and material qualifier.
To speciate by a parameter result temperature for a user-specified
parameter, the Use a Parameter-entered
Emission Temperature, Parameter
Type, and Emission Temperature
Parameter Name fields must be completed, along with the Material Qualifier and Production
Unit fields when applicable. Refer to Emission
Stream Information for additional details.
Enter the process stream
temperature in the Emission Temperature
field and select the corresponding Unit
of measure from the list, when applicable. If the appropriate unit
is not listed, click the Ellipsis
button and add it.
To speciate by a fixed temperature, both fields must contain an entry.
Refer to Emission Stream Information
for additional details.
Click the Noncondensable check box when the process unit is padded by a noncondensable material and select the material from the list.
Enter the system pressure in the Total Pressure field.
Select a corresponding Unit of measure from the list.
If the appropriate unit is not listed, click the Ellipsis
button and add it.
Select a Production Material from the list.
Click the SARA Exempt check box if the process unit should be excluded from SARA reporting.
Click the GHG MRR Exempt check box if the process unit should be excluded from mandatory reporting of greenhouse gases.
Click the Save button on the form.
During an activity, certain air, wastewater, or solid waste material emissions are generated by a source. These emissions may be from a product, raw material, fuel, or process stream. In an actual emission model, you can perform material emission calculations by selecting an emission equation or specifying an emission factor. You can then indicate whether these emissions are released through an emission point or directed to a control device.
The Material Emissions section on the Process Unit Emission Model form displays the materials emitted at the source during the emission model and how their emissions will be calculated. If the section is blank or incomplete, click the Material Calculations button. The Process Unit Material Emission Calculations form is displayed where you can specify details about the materials emitted. For additional information, refer to Defining Material and Material Group Emissions Calculations.
During an activity, certain air, wastewater, and solid waste material emissions may be generated at a source. However, you might not know exactly which materials are emitted at any given time. This situation is commonly encountered in the applied coatings industry where a variety of materials may be used at a single paint booth. To accommodate this situation, you can set up an emission model that covers a class of materials instead of creating a model for each individual material. For instance, you could specify that a group of "Coatings:" are used at a paint booth. To calculate the emission rates of the materials that belong to the group, build an equation that references actual material quantities consumed; you must enter these quantities as inventory transactions in the Essential Chemical Inventory module. (The Chemical Inventory module is required to use this functionality.)
The Material Group Emissions section on the Process Unit Emission Model form displays the material groups emitted at the source during the emission model and how their emissions will be calculated. If the section is blank or incomplete, click the Material Group Calculations button. The Process Unit Material Group Emission Calculations form is displayed where you can specify the material groups emitted and how their emissions should be calculated. For additional information, refer to Defining Material and Material Group Emissions Calculations.
In the User Defined Properties section on the Process Unit Emission Model form, assign user-defined properties to your emission model to track values in emission equations and/or for reporting and recordkeeping purposes. For GHG MRR subpart C impacted sources, the fuel type and the calculation tier can be assigned in this section. Enter validation criteria for each property when applicable. For additional information, refer to User-Defined Properties.
To add user-defined properties
Locate the emission model on the Process Unit Emission Models list, click the link to display the Process Unit Emission Model form, and expand the User Defined Properties section when necessary.
Click Add User Defined Property.
Select the Property
from the list.
The remaining fields displayed are based on the type of property select,
Numeric, Boolean, Text, or Validation List.
Complete the remaining fields
with the applicable validation data and press OK.
The property is displayed as a line item in the User
Defined Properties section. Edit existing property information
using the buttons adjacent to the line item.
Repeat steps 2 through 4 to add other user-defined properties.
Click the Save button on the form.
On the Process Unit Maximum Potential Emission Model form, you can set up models that describe a source's maximum potential to emit (PTE) during a particular activity. Activities might include the production of a product or a specific process. During these activities, the source will generate certain emissions from pollutant materials.
In the maximum potential emission model, specify what the process conditions are at the source, what individual materials are emitted, and where these emissions are directed. Identify an equation to indicate how the emissions from each pollutant material should be calculated.
Maximum potential emission models can also compensate for different operating conditions during an activity through the use of scenarios. Scenarios allow you to calculate the maximum potential emissions when sources are operating under both normal and non-ideal conditions.
You can also use scenarios to store outdated methods of performing calculations that you must maintain for historical reporting and recordkeeping. When you are scheduling production, the effective and shutdown dates are used for determining which emission model and scenario to reference.
To set up maximum potential
emission models
Click Data
Entry > Emission Model Information > Process Unit Max Potential
Models in the Navigation Tree.
The Process Unit Maximum Potential
Emission Models list appears.
Click the New
button.
The Process Unit Maximum Potential
Emission Model form is displayed.
Select an Entity
and Process Unit from the
list for each field.
Tip: The lookup tool next to the Process
Unit field can be used to select an entity/process unit combination.
Select a Model
name and Scenario name from
the list for each field. (Only scenarios that were associated with
the selected model will be listed.)
If the appropriate value is not listed for a field, click the Ellipsis button next to the field
and add it.
Select an emissions calculations time frame (e.g., hour, day, week, etc.) for the model from Time Basis field's list.
Enter an Effective Date and Shutdown Date for the model, or click the Calendar button and select the date. If the shutdown date is left blank, the model will always be effective.
Select a GHG Scope when applicable.
Expand the Model Description section and add text that identifies the model.
Add information in the General Emission Information and Material Emissions sections.
Click the Save button on the form.
Repeat steps 2 through 10 to add other maximum potential emission models.
In the General Emission Information section on the Process Unit Maximum Potential Emission Model form, you can enter process condition information for a maximum potential emission model.
The emission stream temperature is the vapor stream temperature to be used in vapor-liquid equilibrium (VLE) calculations. This value is also used as the inlet temperature if the source is connected to a control device that uses the condenser equation to model its abatement.
If you are modeling a tank that uses an inert gas as a padding, you can select the noncondensable material used and enter the system pressure. For example, nitrogen gas is commonly used in tanks. Only materials whose vapor pressure method was marked as "Noncondensable" in the Material Composition and Properties section on the Material form will be available.
You can also specify a production material if you want to relate the activity occurring within the model to the production of a specific material. This information is used for recordkeeping purposes only.
To establish maximum potential
emission model process conditions
Locate the emission model on the Process Unit Maximum Potential Emission Models list, click the link to display the Process Unit Maximum Potential Emission Model form, and expand the General Emission Information section when necessary.
Enter the process stream temperature in the Emission Temperature field.
Select the corresponding
Unit of measure from the list.
If the appropriate unit is not listed, click the Ellipsis
button and add it.
Click the Noncondensable check box when the process unit is padded by a noncondensable material and select the material from the list.
Enter the system pressure in the Total Pressure field.
Select a corresponding Unit of measure from the list.
If the appropriate unit is not listed, click the Ellipsis
button and add it.
Select a Production Material from the list.
Click the Save button on the form.
During an activity, certain air, wastewater, or solid waste material emissions are emitted by a source. In a maximum potential emission model, you can perform material emission calculations using an emission equation or by specifying a steady emission rate. You can then indicate whether these emissions are released through an emission point or directed to a control device.
In the Material Emissions section on the Process Unit Maximum Potential Emission Model form, you can view the material emission calculations to be performed in the maximum potential emission model. If the section is blank or incomplete, click the Material Calculations button. The Process Material Maximum Potential Emission Calculations form is displayed where you can specify the materials emitted and how their emissions should be calculated. For additional information, refer to Defining Material Maximum Potential Emission Calculations.
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