This page provides an overview of the dehydrators source type reporting requirements for Subpart W. 

Please see Reporting Form Instructions on downloading the blank reporting form and uploading the completed reporting form.
You may also refer to Optional Calculation Spreadsheet Instructions to download the Subpart W calculation spreadsheet.

The dehydrators source type is applicable to Onshore petroleum and natural gas production (98.236(a)(2)), Onshore natural gas processing (98.236(a)(3)), and Onshore petroleum and natural gas gathering and boosting (98.236(a)(9)) facilities.

Indicate if the facility has the source type via the radio buttons.

If the source type is present you must report required emissions.

If the facility has the source type, then indicate whether missing data procedures were used.

Reporting Requirements

Table E.1 Small Glycol Dehydrators must be completed if the facility has any with glycol dehydrators with an annual average daily throughput less than 0.4 MMscfd. Required data elements include:

• Total number of small glycol dehydrators (98.236(e)(2)(i))

• What vent gas controls devices are used? (98.236(e)(2)(ii-iv))

• Number of small glycol dehydrators by vent control type (98.236(e)(2)(ii), 98.236(e)(2)(iv)(A))

• Specify the type of control devices other than vapor recovery, flare or regenerator firebox/fire tube, and specify the number of small glycol dehydrators that route emissions to each type of control device  (98.236(e)(2)(iii))

• For dehydrators that route emissions to a flare or regenerator firebox/fire tubes, report total CO₂, CH₄ and N₂O emissions from the flare or regenerator firebox/fire tubes (98.236(e)(2)(iv)(B-D))
• CO₂ and CH₄ emissions that were not routed to a flare or regenerator firebox/fire tubes (98.236(e)(2)(v)(A-B))

Table E.1 Small Glycol Dehydrators

Table E.2 Desiccant Dehydrators must be completed if the facility has any desiccant dehydrators with an annual average daily throughput less than 0.4 MMscfd. Required data elements include:

• Total count of desiccant dehydrators (98.236(e)(3)(i))
• What vent gas controls devices are used? (98.236(e)(3)(i))

• Number of desiccant dehydrators by vent control type (98.236(e)(3)(i))

• Specify the type of control devices other than vapor recovery, flare or regenerator firebox/fire tube, and specify the number of desiccant dehydrators that route emissions to each type of control device (98.236(e)(3)(i))

• For dehydrators that route emissions to a flare or regenerator firebox/fire tubes, report total CO₂, CH₄ and N₂O emissions from the flare or regenerator firebox/fire tubes (98.236(e)(3)(i))
• CO₂ and CH₄ emissions that were not routed to a flare or regenerator firebox/fire tubes (98.236(e)(3)(ii-iii))

Table E.2 Desiccant Dehydrators

Table E.3 Large Glycol Dehydrators must be completed if the facility has any glycol dehydrators with a throughput >0.4 MMscfd. Required data elements for each large glycol dehydrator include:

• Unit ID or Name (98.236(e)(1)(i))
• Sub-Basin ID (required for Onshore petroleum and natural gas production facilities only) (98.236(e)(1)(xviii)) - the pick list for this data element is populated based on the (aa)(1) Onshore Production tab of the Smart Form. Be sure a valid Sub-basin ID is used.
• County and State (required for Onshore petroleum and natural gas gathering and boosting facilities only) (98.236(e)(1)(xviii))
• Glycol dehydrator feed natural gas flow rate determined by engineering estimate based on best available data (98.236(e)(1)(ii))

• Dehydrator feed natural gas water content (98.236(e)(1)(iii))

• Dehydrator outlet natural gas water content (98.236(e)(1)(iv))

• Glycol dehydrator absorbent circulation pump type (98.236(e)(1)(v))

• Dehydrator absorbent circulation rate (98.236(e)(1)(vi))

• Report type of absorbent used (98.236(e)(1)(vii))

• Report whether stripper gas is used in glycol dehydrator (98.236(e)(1)(viii))

• Report whether a flash tank separator is used in glycol dehydrator (98.236(e)(1)(ix))

• Total time the glycol dehydrator is operating ([98.236(e)(1)(x))

• Temperature of the wet natural gas (98.236(e)(1)(xi))

• Pressure of the wet natural gas (98.236(e)(1)(xii))

• Concentration of CO₂ in wet natural gas (98.236(e)(1)(xiv))

• Concentration of CH₄ in wet natural gas (98.236(e)(1)(xiii))

• Were any dehydrator emissions vented to a vapor recovery device? (98.236(e)(1)(xv))

• Were any dehydrator emissions vented to a flare or regenerator firebox/fire tubes? (98.236(e)(1)(xvi))

  • If emissions are vented to a flare or regenerator firebox/fire tubes, report CO_2, CH₄ and N₂O emissions from flares or regenerators (98.236(e)(1)(xvi)(A-C))

• Were any dehydrator emissions vented to the atmosphere without being routed to a flare or regenerator firebox/fire tubes? (98.236(e)(1)(xvii))

  • If emissions are vented to the atmosphere without being routed to a flare or regenerator firebox/fire tubes, report CO₂ and CH₄ emissions from venting (98.236(e)(1)(xvii)(A-B))

Table E.3 Large Glycol Dehydrators

Enlarged Views for Table E.3 Large Glycol Dehydrators

Enlarged Views for Table E.3 Large Glycol Dehydrators (continued)

Enlarged Views for Table E.3 Large Glycol Dehydrators (continued)

Enlarged Views for Table E.3 Large Glycol Dehydrators (continued)

Table E.4 Missing data procedures used for Dehydrator emission calculations is required if your facility relied on missing data procedures to develop data elements used in calculating emissions for dehydrators.  These data elements include: 

• Type of Dehydrator

• Unit ID (required for large dehydrators only)

• Parameters
• Measurement Frequency

• Number of quarters missing data procedures were used [98.236(bb)(1)] (required only if the measurement frequency was quarterly)

• Total number of hours in the year missing data procedure was used [98.3(c)(8)], [98.236(bb)(2)] (required unless the measurement frequency was quarterly, annually, biannually,  or N/A)

• Procedures used for missing data [98.235(h)]

   

Table E.4 Missing data procedures used for Dehydrator emission calculations

 

Total Emissions

The total emissions roll-up at the top of the sheet reflects the sum of each gas emission reported for the source type. These summations are calculated automatically by the Smart Form and tabulated on the Introduction tab.