DEQ continues to lead the way in finding and reducing emissions at oil and gas facilities

Air Quality Division
Published: May 20, 2021

In May of 2020, the Wyoming Department of Environmental Quality (DEQ), Air Quality Division (AQD) and the US Environmental Protection Agency (EPA) released a report for the first phase of a study to better quantify performance of enclosed combustion devices (ECD’s), also known as or enclosed flares, at oil and gas facilities.

ECD’s or enclosed flares are emission control devices at oil and gas facilities that ensure Volatile Organic Compound (VOC) pollution is at least 98% destroyed prior to reaching Wyoming's air. This is important because VOC’s are a precursor to the formation of ozone.

This study, "Measuring Enclosed Combustion Device Emissions using Portable Analyzers'', found that ECD’s or enclosed flares at various sites had a wide range of hydrocarbon destruction efficiency from 22% to 99%. One of the main reasons for this study was to see if there were new tools or emerging technology that regulators and industry could leverage to better test the control efficiency of these ECD’s.

According to Jeff Wendt, AQD Principal Engineer, federal regulations have only one approved method to test ECD's, a method which involves complicated simultaneous testing of the inlet gas stream to be combusted and the output emissions of the ECD’s.  Due to the variable production rates and inconsistent flow rates at well sites, this inlet-outlet test method can be challenging to perform, and it takes several hours to complete a full test.

"The results from the inlet-outlet testing method have varied significantly, due to the amount of fuel or VOC's that are feeding into the ECD at a particular time," said Wendt. "We've seen tests where the end numbers do not make much sense."

Because of these varied results, DEQ and EPA began looking into a new method to better quantify ECD control performance, specifically using improved “Portable Analyzer” technology while following a much simpler outlet only test method.

Portable Analyzers have become standard equipment in the oil and gas fields and are typically used to perform maintenance or emissions checks on engines, not unlike how a car exhaust system might be tested.  Simply by inserting the Portable Analyzer probe into an engine exhaust release point or “stack”, the user gets a real-time output value for common pollutants such as Nitrous Oxides (NOx), Carbon Monoxide (CO), and Hydrocarbons.  The Portable Analyzer has become an indispensable tool for production field engine maintenance and emission testing in recent years.

As Portable Analyzer devices have become more robust and more accurate due to recent technological innovations, it was suspected that Portable Analyzers could be used to assess hydrocarbon destruction efficiency in ECD’s.  More importantly, it was suspected that they could be used to optimize ECD control efficiency quickly and easily.  This study found that the use of these devices showed highly promising results. 

Using a simplified outlet only method developed by DEQ’s Air Quality Engineer Jared Beck, the study found that Portable Analyzers could be used to better equip regulators during inspections for spot checks of combustion devices at production facilities. Additionally, Portable Analyzers can assist industry in their continued efforts to meet all regulatory requirements while also significantly reducing costs and time associated with the traditional testing method. 

Beck managed and spearheaded the study from the DEQ side, while working closely with the USEPA and industry partners to help guide the project to a successful completion.

“Not only did this study demonstrate we can quickly evaluate ECD performance, but industry effectively made simple changes which optimized control efficiency using the live data,” said Beck. “Using this approach, industry is able to determine and implement best management practices to help ensure ECD performance over time. I was fortunate to have the assistance of Cindi Etcheverry and Staff Polk from our Pinedale office whose oil and gas knowledge was critical to the study’s success.”

"Perhaps the most important thing that came out of this study was the collaborative effort by DEQ, EPA, and Wyoming’s industry partners to optimize the performance of these combustion devices while looking at real-time data from a Portable Analyzer," said Wendt. “Without everyone working together, this effort would not have been possible.”

A second phase of this study was conducted this last fall by DEQ and EPA. One goal of Phase II was to compare the approved inlet-outlet testing method to the newly developed Portable Analyzers method in side-by-side testing as they simultaneously measure enclosed flare emissions. The results, due to be released later this year, will hopefully show the correlation between both testing methods. 

"The hope is that this study will ultimately lead to the Portable Analyzers to be an approved EPA method for testing these enclosed combustion devices," said Wendt. “At the very least, it has already shown that the Portable Analyzers can be and should be used to optimize ECD performance frequently in field conditions.  This whole project has been a big win for anyone who breathes air in Wyoming, and these results are going to be highly valuable to other energy producing states and the companies which operate in them as well.”

To view the report, please click here.

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