American Oil and Gas Reporter - October 2016 - 84

SpecialReport: Natural Gas Update

Vapor Recovery Equipment Advances
By Colter Cookson
Federal and state agencies are adopting
policies that mandate capturing methane
emissions from oil and gas operations,
putting vapor recovery on the critical
path to achieving compliance with greenhouse gas regulations.
The biggest driver behind today's
vapor recovery activity is the Environmental Protection Agency's New Source
Performance Standard 40 CFR, Part 60,
Subpart OOOO, says Gabriel Kent, lead
environmental specialist with OTA Compression. Published in the Sept. 23,
2013, Federal Register, Quad O limits
the amount of volatile organic compounds coming from storage tanks that
hold crude oil, condensate, produced
water, or intermediate hydrocarbon liquids.
"The rule applies to new sites and to
any sites that have been reconstructed or
modified (for example, any site where a
new well has been drilled) since Aug.
23, 2011," Kent notes. "If the rule covers
a site, the operator has to measure the
vapors coming from storage tanks to determine if any tank is emitting more than
six tons of VOCs a year. If one is, 95 per-

cent of those emissions must be recovered
using a vapor recovery unit or combusted
to minimize their environmental impact."
The six-ton threshold is easy to exceed,
Kent warns. "It generally takes only 1015 barrels of oil a day to produce six
tons of VOCs a year, so it is easy for
Quad O to affect even marginal wells,"
he says.
"To calculate VOC emissions per tank,
an operator must first determine if the
tanks are in series or parallel," Kent says.
"If they are in series, meaning that liquids
always flow into one tank and spill over
into the others, all the flash occurs in the
first tank for purposes of determining affected facility status under Quad O. If
they are in parallel, meaning the liquids
flow into all tanks by means of a manifold,
the flash occurs in all tanks equally, according to the rule.
"There is a common misconception
that commingling vent lines such that
the tanks share working breathing flash
emissions allows the operator to treat the
tanks as if they are in parallel and divide
the emissions equally across all tanks,"
Kent comments. "However, a commingled
vent line is not taken into consideration
in the definitions of the series and parallel

The GTO30E electrically driven
vapor recovery unit has the reliability and record-keeping features
needed to meet federal and state
limits on volatile organic compound, greenhouse gas and
methane emissions that are driving interest in vapor recovery,
OTA Compression says. The
unit's highlights include logging
of run, idle, and fault time, automatic start-and-stop capabilities,
Class I, Division 2 components,
and support for SCADA.

84 THE AMERICAN OIL & GAS REPORTER

arrangements."
Ignoring Quad O can be costly, Kent
says. "Texas can levy fines as high as
$25,000 a day per violation. Oklahoma
limits fines to $10,000 a day per violation,
but that adds up quickly," he says. "Most
states now have access to helicopters that
can fly over sites and use optical gas imaging to detect leaks. Identifying the exact
source will require them to send someone
to the area, but they now have tools that
make finding violations easier."
On sites where there is no pipeline to
take recovered gas to market, or where
the recovered volumes are too small to
justify a vapor recovery unit, Kent recommends an enclosed combustor. "We
are seeing the popularity of combustors
grow relative to flares, especially in
areas that are near the public," he says.
"Combustors put the flame out of sight
and out of mind. They have a quiet combustion process that produces no smoke
or odors, so people have no reason to
complain."
If a vapor recovery unit makes sense
for the application, Kent says it is best
to buy it from a turnkey provider. "Get
a package that comes with everything
needed to install the unit and perform
the monitoring EPA requires," he stresses.
"I've seen too many producers end up
flaring because their vapor recovery
unit needed a part that had to be backordered."
He also suggests investing in automated
equipment. "Have supervisory control
and data acquisition or some other form
of communication that enables remote
troubleshooting and restarts," he details.
"The less time mechanics spend traveling
to and from sites, the more likely it is
they can keep the unit operating at the
required uptime of 95 percent.
"It is important to document achieving
that goal," Kent continues. "For that
reason, look for equipment that comes
with data loggers and can generate userfriendly reports."
Because permitting requirements vary
from site to site, especially in nonattainment areas, Kent encourages close collaboration between environmental and
operations departments. "Partner with
companies that know compliance requirements," he adds. "They will be able to
design equipment that meets the requirements at a reasonable cost."

American Oil and Gas Reporter - October 2016

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