Emergency Shutdown

Providing Reliable Shutoff for Gas Pipeline Valves
No doubt. Shale gas fields hold vast untapped stores of natural gas. As drilling in these fields has become

We would have had to routecommercial power to the site ata huge cost. Emerson’s solution
operates on solar power. It also
lets us check site status fromour control room hundredsof miles from the site. We aresaving money and time.

increasingly important, sites have become more plentiful — producing gas and oil under high pressure.
Traditionally, drilling sites and pipelines have been in remote locations. Recently, however,population centers have moved into closer contact with the industry. As a result, regulations havechanged to assure safety for the population.
In the event of an emergency, the application calls for rapid-closing emergency shutdown valves. To
effectively provide emergency shutdown, challenges can include lack of power at the site, uncertain
reliability, and difficulty getting personnel to the valve site.

Design Engineer with Pipeline Company

What if…
As the map shows,• Power could be obtainedat the valve site locallywithout routing localpower lines?

many busy highways
cross pipelines
carrying natural gas.
Shutoff valves must
be present to isolate• The valve solution could becomplete and unfailing?
• Operators could monitor
and control the valve froma control room far away?

dangerous issues andprotect people.

Lack of External PowerThe remoteness of a valve site often means that no commercial power is available locally, and theexpense of routing power for the electric motor actuator can be prohibitive. Normally, engineers
would choose to use a gas/hydraulic actuator and power it with the pipeline gas, but that will notwork if the pipeline has a high H2S gas content.

Unsure of Reliability and Speed
When pipelines cross highways or pass through communities, safeguarding people and property
becomes top priority. The resulting focus on safety means the valve solution must operate without
fail — even if the valves are operated infrequently or only during annual testing. In many cases,
actuators absolutely must close in less than 12 seconds after signal input, and the solution has noallowance for inadvertent or false closures.

Personnel Not at the Valve Site
In pipeline applications, facility personnel often must travel long distances to reach the valve site;
quickly closing the valve locally using a manual pump is not possible. In addition, the possible presenceof H2S gas prohibits personnel from investigating a potential leak at a site. Instead, the actuator
must close the valves remotely and/or automatically. If the control system is part of the solution, thesystem must monitor the pipeline pressure, react if it detects linebreak conditions, and signal theactuator to close the line valves. Overall, the system must be reliable with minimal maintenance.

Emergency ShutdownLocal PowerTo obtain power for remote valve sites, some Emerson solutions take advantage of solar power —readily available. A battery-powered electrohydraulic system provides the hydraulic power to charge
the hydraulic accumulators which provide pressure for two complete strokes of the actuator. A solar
panel bank keeps the batteries for the electrohydraulic system charged.

Reliability and Speed
Emerson brings decades of experience and high performance to challenging valve applications
where reliability is crucial. Part of the reliable solution can be Emerson’s Shafer rotary vane type
actuator — its constant torque output ensures that the specified safety factor will not diminish at
various positions during the valve stroke. The hydraulic valve actuator operates the valve smoothly
and hydraulic fluid protects the internal components from the harsh environments. The Shafersystem control valves are engineered to deliver the hydraulic fluid from the accumulators to meet
specified speed requirements.

Remote Control
Emerson can design a system solution that monitors for linebreak conditions and reacts if setpoints
are exceeded. A trial setting feature allows the customer to determine normal pressure variations
and compensate before putting the system into full service. In addition, if the accumulator pressureor battery power falls below operational levels, the system can issue an alarm to the operator —many miles away. Status can be communicated and the valve closed remotely via cell phone, radio,or phone line.

“The solution suppliedby Emerson is doing
what it is supposed todo. There has not been
any field issues since
the installation months
ago and it is sending usthe data we need. We
were able to operate
the system, establish
comfortable set points,
and avoid inadvertent
closures. This is what
we like since we have
limited resources anda busy schedules. We
intend to use the same
system on other criticalinstallations in ourpipeline systems.”
Coordinator - Facilities
Engineer for large
midstream pipeline in Texas© 2013 Emerson Process Management. All rights reserved.
The Emerson logo is a trademark and service mark of Emerson Electric Co. “Brand mark listing” are marks of one of theEmerson Process Management family of companies. All other marks are property of their respective owners.

www.EmersonProcess.com/Shafer

VA-PSB-ES01 10-13

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