Mercury in Petroleum and Natural Gas: Estimation of Emissions from Production, Processing, and Combustion

by

S. Mark Wilhelm
Mercury Technology Services
23014 Lutheran Church Rd.
Tomball, TX 77375

EPA Project Officer
David A. Kirchgessner
National Risk Management Research Laboratory
Research Triangle Park, NC 27711

Prepared for:

U.S. Environmental Protection Agency
Office of Research and Development
Washington, DC 20460

ABSTRACT

Mercury is a trace component of all fossil fuels including natural gas, gas condensates, crude oil, coal, tar sands and other bitumens. The use of fossil hydrocarbons as fuels provides the main opportunity for emissions of the mercury they contain to the atmospheric environment but other avenues also exist in production, transportation and in processing systems. These other avenues may provide mercury directly to air, water or solid waste streams. This document examines mercury in liquid and gaseous hydrocarbons that are produced and/or processed in the United States for the purpose of estimating, to the extent possible, emissions of mercury to the U.S. environment from petroleum and natural gas.

Although the masses of petroleum and natural gas processed and consumed in the U.S. are very large, only limited amounts of information are available concerning mercury in gas and oil processed domestically. This report compiles existing information and data on mercury in petroleum and natural gas and examines the current state of knowledge of the amounts of mercury in petroleum and gas produced and imported to the U.S. In addition, the distribution and transformation of mercury in production, transportation and processing are considered relative to the determination of mercury in air emissions, wastewater, and products from oil and gas processing facilities. Finally, the fates of mercury in combusted gas and liquid fuel products are examined.

The mercury associated with petroleum and natural gas production and processing enters the environment primarily via solid waste streams (drilling and refinery waste) and via combustion of fuels. In total the amount may exceed 10,000 kg yearly but the present estimates are uncertain due to lack of statistical data. The amounts in solid wastes and atmospheric emissions from combustion are estimated to be roughly equal. Solid waste streams likely contain a much higher fraction of mercuric sulfides or other insoluble compounds than water soluble species and thus the bioavailability of mercury from this category is much more limited than that which derives from combustion.

This report is intended to assist in the identification of those areas that require additional research, especially the needs associated with measuring the concentrations of the various chemical species of mercury in the various feedstocks and waste streams associated with the oil and gas industry. Acquisition of additional information will be necessary if accurate estimates of the magnitudes of mercury emissions associated with U.S. petroleum and natural gas are to be accomplished.

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