Emissions reporting in dehydration and refrigeration facilities - Spring 2022 update
CO2 and methane emissions are a top priority for governments and corporations, but the reduction of volatile organic compounds (VOCs) – especially benzene – continues to be important. VOC emissions management is particularly critical for dehydration and refrigeration facilities where these emissions are localized and harmful to health.The emissions from these types of facilities are regulated by various jurisdictions in North America.
Changes in methane regulation in Western Canada
The Alberta Energy Regulator (AER) has been a global leader in introducing and regulating benzene and methane emissions from these facilities as part of Directive 39 and Directive 60. Recently, new limits have come into effect, effective January 1, 2022, to put a cap on methane emissions (summarized in the table below). In British Columbia (BC), the Oil and Gas Commission (OGC) has also mandated new methane limits.
On or after January 1, 2022
68 kg/day (24.8 tonnes/year if operating 365 days a year)
Before January 1, 2022
109 kg/day (39.8 tonnes/year if operating 365 days a year)
* Dehydration or Refrigeration facility using glycol
Companies need to ensure that methane emissions for dehydration and refrigeration facilities are calculated, and that these facilities operate under both the benzene and methane limits.
It is important to note that the OGC has recently introduced a new inventory list template. Based on our team’s discussions with the OGC regarding CY2021 reporting, either the old or new inventory list template may be used to report the benzene emissions inventory in BC (due July 1, 2022).
What impacts benzene and methane emissions?
Operational factors don’t necessarily impact benzene and methane emissions in the same way:
- Regenerator column overhead tanks and condensers reduce benzene, but not methane
- The use of stripping gas has a much greater impact on methane emissions
- The use of Kimray (energy exchange) pumps results in much higher methane emissions in dehydration and refrigeration facilities compared to electric or pneumatic pumps
- Flash tanks preferentially flash methane vs. benzene, so flash tank controls would mainly decrease methane emissions
- Benzene and methane emissions are approximately proportional to glycol circulation rate
Therefore, key operational changes which would reduce methane emissions include:
- Reducing the circulation rate
- Reducing or eliminating stripping gas
Projects which would reduce methane emissions include:
- Installation of a flash tank and/or adding flash tank controls
- Pump size reduction
- Conversion of Kimray pump to electric
- Still overhead flare, incinerator, or combustor
- Other combustion options include routing the still overhead to the reboiler burner or compressor engine
At Process Ecology, we can help you evaluate the options for emissions reductions in dehydration and refrigeration facilities.
Site-wide benzene emissions
The reference to site-wide benzene emissions has been a part of AER regulation since 2018 and would soon need to be reported in the new OGC benzene emissions template. While only the dehydration and refrigeration facility benzene emissions (i.e., from the flash tank and still overhead) are required to be reported, companies need to be aware of the magnitude of site-wide benzene emissions, which would include most notably tank emissions, where VOCs are concentrated.
Companies are already required to estimate methane emissions from tanks, and for large facilities, may already be reporting VOCs (including benzene) as part of National Pollutant Release Inventory (NPRI) reporting.
Process Ecology has developed Emissions Advisor, a comprehensive system designed to develop the emissions inventory and report the various regulatory requirements. This system makes it easy to compile site-wide emissions and apply the calculations for the various reporting types.
We also collaborate closely with companies to ensure that they are quantifying, reporting, and reducing emissions from their facilities.
If you require assistance, please contact us.