American Oil and Gas Reporter - May 2015 - 107

SpecialReport: Gas Compression Technology
think there are an ample number of emissions solutions available, at least as currently regulated."
Knox says the next big step in emissions reduction is capturing methane inadvertently released during drilling, completion and production operations. "It is
going to be very important for compression

providers to work in concert with producers to minimize fugitive emissions
from compressor packages, as well as
find ways to use compressors to capture
emissions coming off production valves,
control systems, and other equipment
throughout production facilities," he states.
To that end, oil and gas companies as

well as midstream facility operators are
installing smaller-horsepower compressors
dedicated to vapor recovery. Vapor recovery units range in size from 20 horsepower at individual pad sites to 400
horsepower for storage tanks at central
production and processing facilities, he
observes.
Ì

Bifuel Capability Adds Engine Options
By Al Pickett
Special Correspondent

With operators increasingly focused
on containing or reducing costs, engine
manufacturers and compressor/hydraulic
fracturing fleet operators are offering
bifuel or dual fuel technology to help
lower fuel bills.
The difference between bifuel and
dual fuel depends on whom one asks,
suggests Axel zur Loye, chief engineer
for dual fuel technology at Cummins Inc.
"Bifuel means different things to different
people. In the Cummins world, dual fuel
engines are capable of running on either
diesel fuel or a combination of diesel
and natural gas," he says. "Bifuel engines
can run on two fuels separately, such as
propane or natural gas."
The terminology is just the opposite
for Altronic, a division of HOERBIGER
Engine Solutions, according to Keith
Brooks, senior vice president of original
engine manufacturer sales.
"For us, bifuel means burning two fuels," he reveals. "You have to have diesel,
while dual fuel means you can run the
engine on this gas or that, such as a car
that can run on natural gas or gasoline.
But it is just a matter of semantics."
To add to the confusion, Shane Cannon,
who is business development manager
for Cummins and formerly served as the
company's dual fuel market leader, says
Cummins' engines are called dual fuel in
the United States but bifuel in Canada.
The potential benefits of the technology-whatever the label-are not confusing,
however.
"Several years ago, the question was
whether this technology was viable," zur
Loye recalls. "The answer is yes. Customers are seeing the benefits. We have
seen a lot of progress the last several
years."
Service company giant Baker Hughes
calls the technology bifuel, and Jad Lutfi,

product champion for stimulation equipment technology, says the advantages
are far greater than simply cost savings.
He says using bifuel pumps is also a way
to reduce the environmental footprint of
a company's hydraulic fracturing operation
by replacing some of the required diesel
fuel with clean-burning natural gas.
"It is not fuel reduction only," Lutfi
emphasizes. "It impacts the entire life
cycle of the supply chain. You produce
crude oil, put it in storage, transport it to
the refinery, and then deliver it back to
the well site to power the drilling rig and
hydraulic fracturing pumps. You are going
in a circle, using energy to transport the
diesel and emitting emissions in every
step. By using line gas to power the pumps,
you lower the number of trucks on the
road and eliminate transportation costs."
Improving Technology
Brooks says Altronic released its GTI+
bifuel system in late 2013, which he says
raised the level of technology and allowed

bifuel-equipped engines to perform better.
The GTI+ system works by replacing
the gas train's traditional mechanical gas
pressure regulator with an electronic gas
control valve.
"Any fluid that runs through a pipe
loses pressure as it flows," Brooks observes.
"This means that the pressure sensed at
the outlet of the gas train is not the same
as the gas pressure delivered to the gas
mixer at the turbocharger inlet. The pressure losses from the gas train to the mixer
affect the achievable substitution.
"We placed a pressure sensor in the
mixer where the gas is introduced into
the air flow. In this manner, our system
provides closed loop electronic feedback
to the gas train fuel valve," he details
"By measuring the pressure in the mixer
electronically, the electronic gas valve
responds in a closed loop fashion, eliminating the negative effects of these pressure
losses."
The benefit of the electronic signal,
according to Brooks, is not only an

Altronic's GTI+ bifuel system replaces the gas train's traditional mechanical gas pressure
regulator with an electronic gas control valve. According to the company, measuring
pressure in the mixer electronically eliminates the negative effects of pressure losses
between the gas mixer at the turbocharger inlet and the outlet of the gas train, as well
as improves system response and performance.

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American Oil and Gas Reporter - May 2015

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