Oil and Gas at Your Door? (2005 Edition) - Earthworks

Oil and Gas Development and Impacts
• Barrett Resources Corporation has minimized odors generated at natural gas production
sites, a common source of complaint by surface owners, by using combustion
units designed to destroy vapors released by condensate tanks and glycol dehydrators.
These units also reduce emissions of methane (a greenhouse gas), and other
hydrocarbons that can affect visibility.
Capture Gas Instead of Flaring It
The federal Department of Energy and the Interstate Oil and Gas Compact Commission are
involved in a project to reduce greenhouse gases and NO x emissions and increase oil production
and in California. Gas that would otherwise be flared, and shut-in gas from
California’s oil-fields will be used to generate electricity. Several types of conventional and
new microturbine generators will be tested at selected sites from among California’s 21,000
marginal wells.
Petroleum Technology Transfer Council 358
• Standard glycol dehydrators which are used to remove water from natural gas, typically
vent water and hazardous gases directly into the atmosphere. Glycol dehydrators
are a major source of benzene emissions within the oil and gas industry. 359 Fatalities
from human exposure to high concentrations of benzene have been documented
since the early 1900s, and studies have shown correlations between workplace exposure
to benzene and the onset of certain forms of leukemia. 360 The issue of air emissions
from glycol dehydrators has only been identified in the past few years. Most of
the glycol dehydration units are installed in rural environments; they are typically left
unattended, and emissions are not regularly monitored.
In 1995, the Canadian government announced that it would be limiting benzene
releases through various measures including controlling emissions of benzene from
natural gas dehydrators. A Canadian Working Group composed of industry, government,
and public interest groups produced a document, Best Management Practices
for Control of Benzene Emissions from Glycol Dehydrators, 361 which outlines methods
for minimizing benzene emissions in new and existing plants; and provides more information
on alternatives to glycol dehydration. These include: methanol or glycol injection;
separator packages; line heaters; solid desiccant/molecular sieve plants; membrane
technology; and other commercial processes.
Emissions from glycol dehydrators can be reduced by: optimization of operations;
equipment modifications or replacement; and/or, addition of emission control equipment.
Emission controls such as condensers, flare stacks, and incinerators for still column
vent vapors have been installed by industry at some locations. Research by the
U.S. EPA has indicated that operators of glycol dehydrators often maintain a circulation
rate that is at least two times higher than is needed to remove enough water from the
gas. Therefore, companies can reduce their glycol use by performing simple calculations
to determine the minimum circulation rate needed. By doing so, they will lose less
methane to the atmosphere; improve the dehydrator unit efficiency; and decrease fuel
pump use. EPA has calculated that by doing so, the potential savings for a dehydrator
unit can range from $260 to $26,280 per year. 362
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