Subpart Y Catalytic Cracking, Fluid Coking, and Catalytic Reforming Unit Information
Note: The Cal e-GGRT help system includes general instruction on using the California GHG reporting tool. However, the help system may not explain differences between California and U.S. EPA reporting requirements. Please refer to the ARB reporting website for California-specific reporting requirements and additional help.


This page provides a step-by-step description of how to enter Subpart Y Catalytic Cracking, Fluid Coking, or Catalytic Reforming unit information about this facility.

Adding or Updating Catalytic Cracking, Fluid Coking, or Catalytic Reforming Unit Information

To add or update Subpart Y Catalytic Cracking, Fluid Coking, or Catalytic Reforming unit information for this Facility, locate the CATALYTIC CRACKING UNITS, TRADITIONAL FLUID COKING UNITS, FLUID COKING UNITS WITH FLEXICOKING DESIGN, AND CATALYTIC REFORMING UNITS EMISSIONS SUMMARY table on the Subpart Y Overview page.

Click the link titled "ADD a Catalytic Cracking or Coking Unit."

To edit an existing Catalytic Cracking, Fluid Coking, or Catalytic Reforming Unit, click on the edit icon or the Name/ID link, which is the first column in the CATALYTIC CRACKING AND COKING UNIT-LEVEL EMISSIONS SUMMARY table.

To delete an existing Catalytic Cracking, Fluid Coking, or Catalytic Reforming Unit, click on the delete icon, which is the last column in the CATALYTIC CRACKING UNITS, TRADITIONAL FLUID COKING UNITS, FLUID COKING UNITS WITH FLEXICOKING DESIGN, AND CATALYTIC REFORMING UNITS EMISSIONS SUMMARY table.

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Subpart Y collects the following data about your Catalytic Cracking, Fluid Coking, or Catalytic Reforming unit:

  • A unique name or identifier, plus optional description for this unit (see also About Unique Unit Names)
  • Specify the type of unit:
    • Fluid Catalytic Cracking Unit
    • Thermal Catalytic Cracking Unit
    • Traditional Fluid Coking Unit
    • Catalytic Reforming Unit (see note below)
    • Fluid Coking Unit with Flexicoking Design (see note below)
  • For each unit, answer the following question: Do you operate and maintain a CEMS that measures CO2 emissions according to subpart C? This means that both a flow meter and a concentration monitor need to be installed. If so, you must use the CEMS methodology for measuring CO2 emissions from this unit. Click either Yes or No.

For Catalytic Reforming Units, if you are using Equation Y-11, please enter your average coke burn-off quantity (kg coke / cycle or kg coke / measurement period) in the "Description (optional)" text box on the Unit Information page. If using equation Y-11, average coke burn-off quantity is a required reporting element. The only location where this information can be submitted is in the "Description (optional)" field on the Unit Information page.

For Fluid Coking Units with Flexicoking Design, you will be asked if the GHG emissions from the low heat value gas are accounted for in Subpart C.

  • If your answer to this question is 'yes', you are only required to report maximum rated throughput of the fluid coking unit with flexicoking design
  • If your answer to this question is 'no', you are required to report maximum rated throughput of the fluid coking unit with flexicoking design and the methods used to calculate emissions per the sections below

When you are finished entering the required information, click NEXT.

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For Catalytic Cracking or Coking units that are NOT monitored by CEMS, Subpart Y also collects the following data:

  • Maximum rated throughput of the unit (bbl per stream day)
  • Method used to calculate CO2 emissions (only appears if you select No for using a CEMS):
    • 98.253(c)(2) - Equation Y-6 and continuous monitor for flow (but not meeting the CEMS monitoring requirements of 98.253(c)(1); e.g., not meeting the full CEMS quality assurance requirements)
    • 98.253(c)(2) - Equation Y-6 and Y-7a
    • 98.253(c)(2) - Equation Y-6 and Y-7b
    • 98.253(c)(3) - Equation Y-8 (option appears only for Catalytic Cracking or Coking units; available only for catalytic cracking units and fluid coking units with rated capacities of 10,000 barrels per stream day (bbls/sd) or less that do not use a continuous CO2 CEMS for the final exhaust stack)
    • 98.253(e)(3) - Equation Y-11 (option appears only for Catalytic Reforming units)
  • Method used to calculate CH4 emissions:
    • Equation Y-9
    • Unit-specific measurement data
    • A unit-specific emission factor based on a source test of the unit
  • Method used to calculate N2O emissions:
    • Equation Y-10
    • Unit-specific measurement data
    • A unit-specific emission factor based on a source test of the unit

When you are finished entering the required information, click SAVE.

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For Catalytic Cracking or Coking units that are monitored by CEMS, Subpart Y also collects the following data:

  • Maximum rated throughput of the unit (bbl per stream day)
  • Method used to calculate CH4 emissions:
    • Equation Y-9
    • Unit-specific measurement data
    • A unit-specific emission factor based on a source test of the unit
  • Method used to calculate N2O emissions:
    • Equation Y-10
    • Unit-specific measurement data
    • A unit-specific emission factor based on a source test of the unit

When you are finished entering the required information, click SAVE.

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Adding or Updating Catalytic Cracking or Coking Unit Emissions Information

This section provides a step-by-step description of how to enter Subpart Y Catalytic Cracking or Coking unit emissions information.

To add or update CO2 emissions information for a catalytic cracking or coking unit that is monitored by CEMS, please refer to the Subpart Y Emissions Information for Process Units Monitored by CEMS help page. CH4 and N2O emissions information for catalytic cracking or coking units that are monitored by CEMS are reported separately per the instructions below.

To add or update CO2, CH4, and N2O emissions information for a catalytic cracking or coking unit that is NOT monitored by CEMS OR CH4 and N2O emissions information for a catalytic cracking or coking unit that is monitored by CEMS, locate the CATALYTIC CRACKING UNITS, TRADITIONAL FLUID COKING UNITS, FLUID COKING UNITS WITH FLEXICOKING DESIGN, AND CATALYTIC REFORMING UNITS EMISSIONS SUMMARY table on the Subpart Y Overview page, and click OPEN.

Note that Fluid Coking Units with Flexicoking Design for which the GHG emissions from the low heat value gas are accounted for in Subpart C require no emissions or additional data under Subpart Y thus the OPEN button is black and has no function.

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Depending on the methods selected to calculate CO2, CH4 and N2O emissions (see previous section titled “Adding or Updating Catalytic Cracking, Fluid Coking, or Coking Catalytic Reforming Unit Information”), you will be presented with screens to collect the respective CO2, CH4 and N2O emission results and additional data. Each specific screen is discussed below.

CO2 Emissions Calculation: 98.253(c)(2) – Equation Y-6 and Flow

The annual CO2 emission rate from the unit operations is required. To calculate this value download the spreadsheet by clicking the link titled “Use Y-6 spreadsheet to calculate.” Fill in the spreadsheet using the instructions in the spreadsheet. After completing the spreadsheet, upload the file using by clicking the browse button, selecting the file from the appropriate directory, and clicking the blue UPLOAD button.

Subpart Y also collects the following CO2 emission data:

  • Annual average flow rate of exhaust gas (dscfh)
  • Manufacturer's recommended method used for annual average flow rate of exhaust gas
  • Number of hours missing data procedures were used for annual average flow rate of exhaust gas (hours)
  • Annual average percent CO2 in exhaust gas stream (percent by volume - dry basis)
  • Manufacturer's recommended method used for annual average percent CO2 in exhaust gas stream
  • Number of hours missing data procedures were used for annual average percent CO2 in exhaust gas stream (hours)
  • Annual average percent CO in exhaust gas stream (percent by volume - dry basis)
  • Manufacturer's recommended method used for annual average percent CO in exhaust gas stream
  • Number of hours missing data procedures were used for annual average percent CO in exhaust gas stream (hours)

The Equation Y-6 Summary and monitored flow requirements are presented in the screenshot below. You can hover over an element in the equation to reveal a definition of that element.

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CO2 Emissions Calculation: 98.253(c)(2) – Equation Y-6 and Y-7a

The annual CO2 emission rate from the unit operations is required. To calculate this value download the spreadsheet by clicking the link titled “Use Y-6 and Y-7a spreadsheet to calculate.” Fill in the spreadsheet using the instructions in the spreadsheet. After completing the spreadsheet, upload the file using by clicking the browse button, selecting the file from the appropriate directory, and clicking the blue UPLOAD button.

The Equation Y-6 and Y-7a Summaries are presented on the page. You can hover over an element in the equation to reveal a definition of that element.

Subpart Y also collects the following CO2 emission data:

  • Annual CO2 emission from this unit (metric tons)
  • Annual average percent CO2 in exhaust gas stream (percent by volume - dry basis; 0 ? x ? 100)
  • Describe the manufacturer's recommended method that was used for annual average percent CO2 in exhaust gas stream
  • Number of hours missing data procedures were used for annual average percent CO2 in exhaust gas stream (hours)
  • Annual average percent CO in exhaust gas stream (percent by volume - dry basis; 0 ? x ? 100)
  • Describe the manufacturer's recommended method that was used for annual average percent CO in exhaust gas stream
  • Number of hours missing data procedures were used for annual average percent CO in exhaust gas stream (hours)
  • Annual average volumetric flow rate of exhaust gas from this unit prior to the combustion of other fossil fuels (dscfh)
  • Annual average flow rate of inlet air (dscfh)
  • Annual average flow rate of oxygen enriched air (a value of "0" may be entered if inlet air is not oxygen enriched to avoid validation errors) (dscfh)
  • Annual average percent O2 in exhaust gas stream (percent by volume - dry basis; 0 ? x ? 100)
  • Describe the manufacturer's recommended method that was used for annual average percent O2 in exhaust gas stream
  • Number of hours missing data procedures were used for annual average percent O2 in exhaust gas stream (hours)
  • Annual average percent O2 in oxygen-enriched gas stream inlet (a value of "0" may be entered if inlet air is not oxygen enriched to avoid validation errors) (percent by volume - dry basis; 0 ? x ? 100)

The Equation Y-6 and Y-7a Summaries are presented in the screenshot below. You can hover over an element in the equation to reveal a definition of that element.

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CO2 Emissions Calculation: 98.253(c)(2) – Equation Y-6 and Y-7b

The annual CO2 emission rate from the unit operations is required. To calculate this value download the spreadsheet by clicking the link titled “Use Y-6 and Y-7b spreadsheet to calculate.” Fill in the spreadsheet using the instructions in the spreadsheet. After completing the spreadsheet, upload the file using by clicking the browse button, selecting the file from the appropriate directory, and clicking the blue UPLOAD button.

Subpart Y also collects the following CO2 emission data:

  • Annual CO2 emission from this fluid catalytic cracking unit (metric tons)
  • Annual average percent CO2 in exhaust gas stream (percent by volume - dry basis; 0 < x < 100)
  • Describe the manufacturer's recommended method that was used for annual average percent CO2 in exhaust gas stream
  • Number of hours missing data procedures were used for annual average percent CO2 in exhaust gas stream (hours)
  • Annual average percent CO in exhaust gas stream (percent by volume - dry basis; 0 < x < 100)
  • Describe the manufacturer's recommended method that was used for annual average percent CO in exhaust gas stream
  • Number of hours missing data procedures were used for annual average percent CO in exhaust gas stream (hours)
  • Annual average volumetric flow rate of exhaust gas from this fluid catalytic cracking unit prior to the combustion of other fossil fuels (dscfh)
  • Annual average flow rate of inlet air (dscfh)
  • Annual average flow rate of oxygen enriched air (a value of "0" may be entered if inlet air is not oxygen enriched to avoid validation errors) (dscfh)
  • Annual average percent N2 in exhaust gas stream (percent by volume - dry basis; 0 < x < 100)
  • Describe the method that was used to measure annual average percent N2 in exhaust gas stream:
    • Method 18 at 50 CFR part 60, appendix A-6
    • ASTM D1945-03
    • ASTM D1946-90-Reapproved 2006
    • GPA 2261-00
    • UOP539-97
    • ASTM D2503-92-Reapproved 2007
    • Chromatographic analysis: manufacturer's instructions
    • Maximum N2 impurity specification
    • Other (specify)
  • Number of hours missing data procedures were used for annual average percent N2 in exhaust gas stream (hours)
  • Annual average percent N2 in oxygen-enriched gas stream inlet (a value of "0" may be entered if inlet air is not oxygen enriched to avoid validation errors) (percent by volume - dry basis; 0 < x < 100)
  • Describe the method that was used to measure annual average percent N2 in oxygen-enriched gas stream inlet:
    • Method 18 at 50 CFR part 60, appendix A-6
    • ASTM D1945-03
    • ASTM D1946-90-Reapproved 2006
    • GPA 2261-00
    • UOP539-97
    • ASTM D2503-92-Reapproved 2007
    • Chromatographic analysis: manufacturer's instructions
    • Maximum N2 impurity specification
    • Other (specify)
  • Number of hours missing data procedures were used for annual average percent N2 in oxygen-enriched gas stream inlet (a value of "0" may be entered if inlet air is not oxygen enriched to avoid validation errors) (hours)

If the gas stream in question does not contain any oxygen-enrichment, then a value of zero may be entered for questions related to oxygen-enrichment.

The Equation Y-6 and Y-7b Summaries are presented in the screenshot below. You can hover over an element in the equation to reveal a definition of that element.

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CO2 Emissions Calculation: 98.253(c)(3) – Equation Y-8

The annual CO2 emission rate from the unit operations is required. To calculate this value download the spreadsheet by clicking the link titled “Use Y-8 spreadsheet to calculate.” Fill in the spreadsheet using the instructions in the spreadsheet. After completing the spreadsheet, upload the file using by clicking the browse button, selecting the file from the appropriate directory, and clicking the blue UPLOAD button.

For this method, Subpart Y also collects the basis for the carbon content value:

  • Weekly or more frequent measurements
  • Periodic (less frequent than weekly but at least quarterly) measurements
  • Semi-annual or annual measurements
  • Historical measurement value
  • Engineering estimate
  • Default value
  • Other

The Equation Y-8 Summary is presented in the screenshot below. You can hover over an element in the equation to reveal a definition of that element

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CO2 Emissions Calculation: 98.253(c)(3) - Equation Y-11

The annual CO2 emission rate from the unit operations is required. To calculate this value download the spreadsheet by clicking the link titled “Use Y-11 spreadsheet to calculate.” Fill in the spreadsheet using the instructions in the spreadsheet. After completing the spreadsheet, upload the file using by clicking the browse button, selecting the file from the appropriate directory, and clicking the blue UPLOAD button.

If you are submitting data for a Catalytic Reforming Unit and are using Equation Y-11, please enter your average coke burn-off quantity (kg coke / cycle or kg coke / measurement period) in the “Description (optional)” text box on the unit ID page. If using equation Y-11, average coke burn-off quantity is a required reporting element. The only location where this information can be submitted is in the “Description (optional)” field on the unit ID page.

For this method, Subpart Y also collects the total number of regeneration cycles or measurement periods.

The Equation Y-11 Summary is presented in the screenshot below. You can hover over an element in the equation to reveal a definition of that element

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CH4 Emissions Calculation: Equation Y-9

The annual CH4 emission rate from the unit operations is required. To calculate this value download the spreadsheet by clicking the link titled “Use Y-9 spreadsheet to calculate.” Fill in the spreadsheet using the instructions in the spreadsheet. After completing the spreadsheet, upload the file using by clicking the browse button, selecting the file from the appropriate directory, and clicking the blue UPLOAD button.

The Equation Y-9 Summary is presented in the screenshot below. You can hover over an element in the equation to reveal a definition of that element.

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CH4 Emissions Calculation: Unit-Specific Measurement Data

For the unit-specific measurement data method, Subpart Y collects the annual CH4 emission from this unit (metric tons).

The CH4 Summary (Measurement Data) is presented in the screenshot below.

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CH4 Emissions Calculation: A Unit-Specific Emission Factor Based on a Source Test of the Unit

For the unit-specific emission factor based on a source test of the unit method, Subpart Y collects annual CH4 emission from this unit (metric tons).

For this method Subpart Y also collects the basis for the CH4 emission factor:

  • Weekly or more frequent measurements
  • Periodic (less frequent than weekly) measurements
  • Average of multiple source tests
  • One-time source test
  • Other (specify)

The CH4 Summary (Emission Factor Based on a Source Test) is presented in the screenshot below.

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N2O Emissions Calculation: Equation Y-10

The annual N2O emission rate from the unit operations is required. To calculate this value download the spreadsheet by clicking the link titled “Use Y-10 spreadsheet to calculate.” Fill in the spreadsheet using the instructions in the spreadsheet. After completing the spreadsheet, upload the file using by clicking the browse button, selecting the file from the appropriate directory, and clicking the blue UPLOAD button.

The Equation Y-10 Summary is presented in the screenshot below. You can hover over an element in the equation to reveal a definition of that element.

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N2O Emissions Calculation: Unit-Specific Measurement Data

For the unit-specific measurement data method, Subpart Y collects the annual N2O emission from this unit (metric tons).

The N2O Summary (Measurement Data) is presented in the screenshot below.

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N2O Emissions Calculation: A Unit-Specific Emission Factor Based on a Source Test of the Unit

For the unit-specific emission factor based on a source test of the unit method, Subpart Y collects annual N2O emission from this unit (metric tons).

For this method Subpart Y also collects the basis for the N2O emission factor:

  • Weekly or more frequent measurements
  • Periodic (less frequent than weekly) measurements
  • Average of multiple source tests
  • One-time source test
  • Other (specify)

The N2O Summary (Emission Factor Based on a Source Test) is presented in the screenshot below.

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See Also

Screen Errors
Using Cal e-GGRT to Prepare Your Subpart Y Report
Subpart Y Summary Information for this Facility
Subpart Y Delayed Coking Unit Information
Subpart Y Asphalt Blowing Unit Information
Subpart Y Coke Calcining Unit Information
Subpart Y Catalytic Cracking, Fluid Coking, and Catalytic Reforming Unit Information
Subpart Y Flares Unit Information
Subpart Y Process Vents Unit Information
Subpart Y Sulfur Recovery Plant Information
Subpart Y Emissions Information for Process Units Monitored by CEMS
Subpart Validation Report

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