US success for electric actuators

Paul Boughton

Latest actuators enable shale gas well compliance with environmental fugitive emission mandates. By Katie Wilson

Advanced electric control valve actuators have delivered an efficient and reliable process control solution and eliminated venting and greenhouse gas emissions in compliance with new environmental protection legislation at remotely sited shale gas installations in the USA.

Most shale wells and flow lines are unmanned and located in remote areas that are difficult and expensive to monitor. Skilled technicians must check data and perform manual shutdowns, increasing costs for the time to travel to site, identifying the problem and stopping the flow, which is not cost-effective or practical.

Actuators provide an ideal solution to automate valves at the remote wells. However, control products are traditionally spring diaphragm actuators powered by the produced gas, but recent EPA (US Government Environmental Protection Agency) mandates now limit this process to lower greenhouse gas emissions to the atmosphere. A shale gas company in Louisiana was therefore looking for an affordable and efficient low power solution that could be run by solar panels to replace existing actuation equipment and control a variety of fluids at line pressures up to 413 bar (6,000 psig).

The main goal

The key objective was to provide an efficient and reliable process control actuator that could be retrofitted on installed valves to reduce costs and downtime. Rotork’s local agent, Setpoint Integrated Solutions, designed an adaption bracket to enable CML-250 actuators to be easily fitted to installed valves and improve the level of control, without venting gas and with the low power demand required for solar powered operation.

Designed for quarter-turn, multi-turn and linear valve operation, robust Rotork CMA actuators perform numerous process control valve, choke valve, metering pump and damper applications demanding precise position control and continuous modulation. 

Single-phase or DC electrical power is all that is required for simplified installation and control valve actuation. Explosion-proof certification to international standards is available for hazardous area applications. Recent developments enable the CMA to be specified with new features encompassing local controls, LCD positional display and programmable fail-to-position performance.

The actuators are permanently lubricated and boast a maintenance-free drivetrain. They can be mounted in any orientation and feature accurate and repeatable position control.

Available digital communication options include HART, Foundation Fieldbus, Profibus, Pakscan, RIRO and Modbus. Meanwhile field selectable adjustments can be conducted for the following: deadband; zero and span; command signal type; standard or reverse acting; manual-auto operation; and output shaft position on loss of signal.

The end results

The success of this solution has enabled the Louisiana shale gas company to standardise on the CMA actuator for future flow control applications. Around the world, increasing numbers of CMA actuators are used for similar duties.

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Katie Wilson is with Rotork in the USA.