Efficient valve automation for remote sites

This article, the second of our ‘View from the other side’ feature columns from our colleagues in the USA, is provided by Chris Warnett.

Chris, a UK expatriate, is the President of CPLloyd Consulting Inc. Rochester NY, providing marketing and applications expertise for the valve and automation industry. Chris has over 38 years of engineering, sales and marketing experience in valves and automation.

Reach him at chris@cplloydconsulting.com Tel 001 585 298 6239.

The conventional perception of a motorized valve has typically been that of a large isolating valve with a heavy duty valve actuator, usually powered by a three phase electrical supply. However, there are many processes where smaller valves are required and the demand for small electric actuators for isolating and modulating applications is steadily growing. Particularly where the environment may be hazardous, hostile or sometimes both.

In recent years valve actuator manufacturers have improved the performance of their small electric actuators. This has been due, in part, to new technologies in electric motor design as well as robust micro control circuitry. Actuator reliability has increased and costs have decreased.

These improvements now allow the demands of some applications to be met with both a commercially attractive and practical solution utilizing motor operated valves, sometimes controlled from a considerable distance.

The improved efficiency of these actuators means that less power is needed to operate some valves.
This is particularly important for applications in remote areas where power distribution lines may not be available. Alternatively, where power is available, it is significantly less expensive to run low voltage single phase or DC power lines compared to higher voltage 3 phase lines.

Oil and gas production

The search for new sources of energy is spreading into even more remote locations. Oil and gas production industries are employing new technologies to exploit resources. The rapid development of unconventional oil and gas production has placed new demands on equipment. More wells are being drilled in remote areas where there is no infrastructure to support conventional technology.

Previously, oil & gas well heads could use the produced gas to provide a power source to operate chokes and shut off valves. However, this practice is now being avoided for environmental and economic reasons.

Remote installations have for some time been capable of control from a distance using telemetry powered by solar panels. The power demand of the remote terminal unit being low enough to be practical. However, to maintain continuous control of well head pressure and flow rates, regular adjustment of the control choke valve is often required. This necessitates the use of an actuator.

Small electric actuators powered by solar power packs are capable of operating many different types of control chokes and other valves.

In applications where many sites are spread over a wide area, each site requires its own solar power pack. The larger the solar pack, the more expensive it is. This means that low power draw actuators are a benefit, if not a necessity. There are two main factors that impact the power draw of the MOV assembly, the force demand of the valve and the efficiency of the actuator.

Some choke valve manufacturers are now producing control chokes that require less torque to operate. This allows a smaller actuator to be used which not only reduces the power usage, but also the cost of the actuator.

As the energy industry changes, then applications change. The valve and actuator industry is responding with developments that support those changes.

Water distribution

Existing infrastructure can often be retrofitted to improve or extend operating life. This applies to any and all industries, but the development of inexpensive compact actuators and the newer methods available to power and control them is providing old installations and infrastructure with a new lease of life.

For example, in many cities around the world the water distribution systems have been in place for many, many decades. Leakage is inevitable with these systems, but as systems age the leakage rates increase. The problems associated with leaking pipes are not limited to the loss of water but also include wasted energy and physical damage from erosion.

Leaks can be mitigated by reducing pressure during off peak hours.

The use of compact electric actuators is ideal to precisely control the pilot pressure activation of larger pressure reducing valves in the distribution system.

The physical constraints of damp sub surface valve pits require robust, compact electric actuators that can operate frequently and reliably to adjust the main valve position. These valves can then be controlled from a central location to manipulate pressure and reduce leakage in an entire municipal area.

Ultimately the best way of reducing leaks is to repair or replace the miles of leaking distribution pipes. However, this takes time and resource. In comparison, the control of pressure in the system can be implemented relatively quickly and cheaply.

By utilizing centralized control of hundreds of pressure regulating valves, a municipality can implement leak mitigation in a shorter time frame.

Published: 18th September 2014