Berkeley Lab Research News


Government-Industry Partnership Focuses on Air Pollution From Oil Storage Tanks

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By Allan Chen,

May 21, 1997

BERKELEY, CA -- At the request of a California consortium of regulators and oil companies, two scientists at the Ernest Orlando Lawrence Berkeley National Laboratory, Donald Lucas and David Littlejohn, have developed a method to measure air pollution emissions from oil storage tanks.

The new method requires a simple device fashioned from parts available at local hardware stores for less than $20. Using this device, they are studying how emissions from these tanks contribute to air pollution in southern California.

Thousands of oil storage tanks dot the landscape of oil-rich counties in southern and central California. Typically 30 feet high and 40 to 50 feet across, they store the crude oil extracted by pumps scattered throughout numerous oil fields that are sometimes as small as a few acres. Drivers on Interstate 5, one of the state's most heavily used north-south routes, are familiar with some of these tanks, but many more lie unseen in the back country, out of view of the state's roadways.

Trying to meet the goals of the Clean Air Act in their districts, regulatory agencies began to develop rules that would affect heavy oil storage tanks for the first time. However, no one has good measurements of the magnitude of air pollution emissions from these tanks. Reducing storage tank emissions could cost the oil industry tens of millions of dollars.

"Air quality districts have to reduce hydrocarbon emissions, and these tanks are an obvious source that they can regulate to help meet the Clean Air Act's requirements," says Lucas, a scientist at Berkeley Lab's Environmental Energy Technologies Division. "But the standard method used to test emissions from tanks, the Reid method, was designed for lighter oil products, mainly gasoline. It doesn't work for the thicker, heavier crude oil."

The oil industry, represented by the Western States Petroleum Association, told regulatory agencies that they would need a new method capable of determining the actual emissions levels from these tanks. WSPA offered to fund a scientific study.

Regulators and industry decided to band together to work out a solution to their problem, and HOST, the Heavy Oil Storage Tank Working Group, was born. A unique collaboration of industry and government, HOST originally consisted of the California Air Resources Board, the Monterey Unified Air Pollution Control District (MUAPCD), the San Joaquin UAPCD, the Santa Barbara UAPCD, the U.S. Environmental Protection Agency and WSPA.

"HOST came to Berkeley Lab first, but it was not clear initially that there was a scientific problem to solve. Then HOST released a request for proposals to 17 commercial testing labs in search of one willing to develop the new procedure and test other methods but only one submitted a proposal, and it was over budget," says Lucas. "We became interested when we realized during discussions with program officers at the Department of Energy that the project offered the chance to solve a scientific problem underlying environmental regulations with a wide impact on the oil industry."

WSPA funded $50,000 and DOE came up with an additional $75,000. DOE and Berkeley Lab became HOST members. "The group has an unusual way of operating," according to Lucas. "HOST makes decisions by consensus. We meet once a month to discuss our results. No one in the group has veto power. Berkeley Lab takes a leadership role in conducting the research but we don't mandate any approaches. A trained mediator helps make sure that our meetings are productive."

Accompanied by safety personnel from HOST member companies, and by a CARB representative, Lucas and Littlejohn visited several tanks in southern California. Using parts bought at a local home improvement store for under $20, they devised a rugged sampler capable of transferring a little of the crude oil from the tank to a standard analytical laboratory without exposing the oil to the atmosphere or losing any emissions from the sample. The old Reid method required a $500 canister.

"The sampler's design is not radically new," explains Lucas, "but we had to prove that it could work here. The Reid method only measures the total pressure of the vapors above the gasoline. We measure the total vapor pressure, as well as how much water vapor, carbon dioxide, methane, ethane, and the heavier components of the crude oil, the so-called reactive organic compounds are in the sample. This is important because only the reactive organic compounds are covered by emission standards and contribute to urban air pollution."

In addition to the sampler, the researchers also tested and developed other procedures for testing the crude in the lab, and on-site at the oil field. Using a mobile laboratory facility, it is possible to run continuous emissions tests of a tank 24 hours a day.

With oil companies providing logistical cooperation such as running power lines, and renting trailers and lifts, Lucas and Littlejohn made measurements at six tanks. These published results show that the measured tanks emit less than a pound of reactive organics per day, much less than was expected.

Thanks to an additional year of funding by DOE and WSPA, they are now testing more tanks over a wider area of southern California, to get a better idea of the magnitude of emissions. "Also, we are moving toward certifying the test procedure with the American Society of Testing and Materials," says Lucas. ASTM certification would give air quality districts and regulated entities throughout the U.S. a standard test of the tanks.

"This is an example of how industry and the government can work cooperatively to solve problems with both scientific and political issues," concludes Lucas. "Berkeley Lab's contribution was to bring independent, scientific credibility to the project."

The researchers presented their work at the Society of Petroleum Engineers/Environmental Protection Agency Exploration and Production Environmental Conference, and have published their account in SPE's Proceedings.

Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified research and is managed by the University of California.

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