Wet Seal Degassing Recovery System for Centrifugal Compressors

The document outlines a method for capturing methane emissions from the seal oil degassing process in centrifugal compressors. By installing high-pressure separators and demisters, operators can recover up to 99% of entrained gas for use as fuel or for reinjection into the system. The analysis indicates that these systems are a cost-effective alternative to retrofitting compressors with dry seals, offering rapid payback periods and significant reductions in atmospheric venting.

• Centrifugal compressors with wet seals often emit methane during the 'degassing' process, where natural gas entrained in seal oil is vented to the atmosphere, frequently through roof vent stacks that are difficult for operators to inspect.
• A wet seal degassing recovery system captures entrained gas using a separator operating at seal oil pressure and a critical orifice for flow control, routing the gas through a demister to remove oil before it is used as low-pressure heater/boiler fuel, high-pressure turbine fuel, or returned to compressor suction.
• Methane emissions from seal oil degassing can average 63 standard cubic feet per minute (scfm) per compressor, reaching as high as 185 scfm. One operator reported recovering 99 percent of emissions from 15 compressors, totaling 1.6 billion cubic feet (Bcf) of gas per year.
• The technology is presented as an economic alternative to retrofitting wet seal compressors with dry seals, which can be prohibitively expensive or cause excessive downtime.
• Estimated capital costs for a single compressor installation are $33,000, while a station with four compressors costs $90,000. At a gas price of $3.00/Mcf, the payback period is estimated at 5 months for one compressor and 3 months for a four-compressor station.

APA

Clean Air Task Force (2014). Wet Seal Degassing Recovery System for Centrifugal Compressors. https://cdn.catf.us/wp-content/uploads/2025/12/03081947/EN_wet-seal-degassing-recovery-sys-for-centrifugal-compressors.pdf

Chicago

Clean Air Task Force. Wet Seal Degassing Recovery System for Centrifugal Compressors. 2014. https://cdn.catf.us/wp-content/uploads/2025/12/03081947/EN_wet-seal-degassing-recovery-sys-for-centrifugal-compressors.pdf.

Wikipedia

{{cite report |author=Clean Air Task Force |title=Wet Seal Degassing Recovery System for Centrifugal Compressors |date=2014 |url=https://cdn.catf.us/wp-content/uploads/2025/12/03081947/EN_wet-seal-degassing-recovery-sys-for-centrifugal-compressors.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{cleanairtaskforce2014wet, author = {{Clean Air Task Force}}, title = {{Wet Seal Degassing Recovery System for Centrifugal Compressors}}, institution = {Clean Air Task Force}, year = {2014}, url = {https://cdn.catf.us/wp-content/uploads/2025/12/03081947/EN_wet-seal-degassing-recovery-sys-for-centrifugal-compressors.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }