American Oil and Gas Reporter - March 2017 - 82

SpecialReport: Midstream & Infrastructure Update

Air-Fuel Ratio
Ignition

Interface/
Diagnostics

Speed
Governing

Mounting &
Hardware

Engine Control Unit

Sensors

Catalyst
Harness

F-W Murphy Production Controls is expanding the range of natural gas engines for which
it offers integrated packages that handle ignition, air/fuel ratio control, and electronic
speed governing. Because these packages are carefully engineered and tested for a specific engine model, they eliminate the need for calibration during setup, improve performance, and maintain emissions compliance.

nical sales manager. "Much of the interest
is coming from the Permian Basin, but
we also are seeing growth in Wyoming
and Colorado," he describes.
If it is available for the engine they
want to retrofit, Schmitt says, customers
are requesting an integrated system that
contains the ignition system, air/fuel ratio
controller, speed governing components,
interface, diagnostic sensors, catalysts,
and engine control unit.
"These packages have been calibrated
and tested for a specific natural gas engine
model. Because of the upfront work involved
in designing them, the customer does not
need to do any setup or calibration," says
Pat Runnels, service and training manager
for FW Murphy's emissions solutions.
The integrated emission control systems
perform so well that they often are installed
in nonattainment areas, Runnels reports.
"As long as the engine's operator is doing
proper maintenance, the engine will stay
in compliance," he adds. "There is no need
to send a technician to the site to recalibrate
the engine ahead of emission tests."
To make the necessary maintenance
as simple as possible, Runnels says the
integrated system includes sophisticated
diagnostics. "We look at 290 points on
82 THE AMERICAN OIL & GAS REPORTER

the system as it operates to identify
issues," he details. "If a spark plug misfires,
the oxygen sensor drifts, or the catalyst
degrades too much, the system will flag
the issue so it can be addressed."
Over time, Runnels says FW Murphy
plans to develop integrated emissions
control systems for larger-horsepower
models. Because each model takes an
average of 400 man hours and 200 hours
on a dynamometer to map, he says that
process will be gradual. Over the past
three years, the company has developed
systems for the 5.9- and 8.3-liter Cummins
engines and the Cummins KTA19, and it
is working on the Cummins GTA 855.
Schmitt reports that FW Murphy has
been working with customers to refine
configurations for specific applications.
"An engine used in a gas lift application
will see different fuel compositions than
one for midstream operations," he notes.
"By taking those differences into account,
we are tightening our curves and improving
the engines' ability to meet specific emissions requirements."
The emission control system's software
allows users to fine-tune NOx and CO
emissions based on company preferences,
Schmitt says. "In some applications, these

adjustments can extend catalyst service intervals," he reports. "For example, if the
engine is producing too much CO but not
much NOx, the operator can switch to
leaner combustion, which will increase
NOx emissions but might reduce CO enough
to bring the engine back into compliance."
To extend service intervals even further,
Schmitt says FW Murphy is offering
larger catalysts. "In applications where
contaminants in the fuel can cause the
catalyst to degrade rapidly, or in remote
locations, the extra life can be quite helpful," he says. "This is particularly true in
areas with especially strict emission requirements, such as Pennsylvania."
The company also offers catalysts with
replaceable elements, but Schmitt recommends sticking with sealed-element
catalysts. "Because they eliminate the
possibility of the catalyst leaking or becoming subject to oxygen intrusion, sealed
catalysts maintain the integrity of the
system, and therefore, its ability to limit
emissions," he explains.
Runnels reports that FW Murphy has
adapted the interface traditionally associated with its integrated control system
to its stand-alone air/fuel ratio controller.
"This interface simplifies setup and operation by providing diagnostic information
and help buttons," he says. "When mechanics have a question, they push a
button and get relevant information rather
than digging through a manual, which
lets them work much faster."
Compressors
As operators have looked for ways to
comply with emissions regulations, electric-driven compressors have gained popularity, reports Levent Caglar, vice president of fleet management for CSI Compressco.
"Gas engines still dominate, but particularly in lower-horsepower applications
such as vapor recovery, we are getting
more requests for electric motors," he
says. "This is especially true in areas
where field gas Btus exceed natural gas
engine tolerance levels. A fuel gas conditioning skid can bring those Btus down,
but sometimes an electric motor is more
economic."
In a boon for compressor uptime,
Caglar says the compression services industry continues to refine its remote monitoring systems. "With remote monitoring,
we are working more proactively, performing predictive maintenance to prevent
downtime before it occurs," he says.

American Oil and Gas Reporter - March 2017

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