Protecting Natural Gas Pipeline Compressor Stations

By Ardem Antabian, Product Line Manager

Pipelines delivering natural gas from drilling production sites to metropolitan areas for consumption are common in many regions around the globe. Some of these pipelines stretch thousands of miles, and remote gas compressor stations are necessary to keep the gas moving efficiently to its final destination. Each station house may have from one to several large gas compression engines that operate 24-hours a day at thousands of horsepower per compressor unit.

Most compressor stations are highly automated as part of the pipeline’s distributed control system. They are controlled from remote Central Operating Centers that are often responsible for multiple pipelines. Even with pipeline automation, there is still a need for routine equipment maintenance and repair within the gas compression stations. There is always the potential as well for accidental combustible gas leaks within the station that require gas detection, alarming and suppression.

Safety monitoring systems must be installed within natural gas pipeline compressor stations to prevent major accidents with the potential to injure people, damage equipment and require pipeline shut-downs. Natural gas is combustible and requires highly reliable gas detectors that monitor to the Lower Explosive Limit (LEL), which is the lowest concentration of gas or vapor that must be present for combustion to occur.

Natural gas compressor stations have a high risk of fire because their operating environment includes a combination of heat, pressure and vibration. Gas enters the station via the pipeline and is processed through to the next station via pressurization accomplished with the compressor engines. Seals and bearings within the compressor engines are the most likely sources of gas leaks.

Within the station’s compressor room, gas detectors are typically mounted up in the ceiling where leaking gas is most likely to collect. The detectors usually feature a built-in display module so they can be read locally within the same room. They are then hardwired from the compressor room to the building’s control room main panel, which also communicates with the entire pipeline’s centralized distributed control system.

Safety monitoring in compressor stations is easily accomplished with fixed combustible gas detectors designed with catalytic bead sensors. They function based on the relatively simple principle that a combustible gas is oxidized to produce heat, resulting in a resistance change that is converted via a standard Wheatstone Bridge temperature transducer to an electronic signal. That signal activates alarms, shut-down and fire prevention systems.

Highly Reliable and Robust Combustible Gas Detection
When determining what type of gas detectors to install, there are several environmental factors that need to be considered. Gas compressor stations are typically high-heat environments due to the operation of the compressors as well as external heat in many climates around the globe. Vibration is another problem, which is caused by the compressor engines. Infrared sensors, for example, are generally a poor choice in high vibration applications.

To prevent compressor station accidents, our Model S4000C Combustible Gas Detector features a highly intelligent microprocessor-based transmitter designed for use with electrocatalytic bead sensors. It monitors gases and vapors within the lower explosive limit (LEL) and provides status and alarm outputs. The advanced electrocatalytic bead sensors are designed to function in applications up to 400°F. To negate the effects of vibration, the S4000C’s electrocatalytic bead sensors are equipped with a third mechanical support arm for highly robust and reliable service.

The S4000C detector simplifies gas compressor station operation and maintenance while reducing downtime by providing an indication of remaining sensor life. Our TGA-1 Remote Gas Test Applicator allows maintenance staff to remotely test sensors placed in ceiling locations without ladders or bucket trucks.

Free S4000C Calibration Demonstration
The S4000C detector is simple to install and calibrate, making it ideal for gas compressor stations. The unit features one person calibration and can virtually self-calibrate by activating a magnetic switch and applying gas. Click here to view a free interactive demonstration, which shows how easily you can calibrate the S4000C.

If you’re having a problem with combustible gas detection in your plant, chances are that our expert Technical Staff has seen it before and can help you with the answers. We’ll visit your plant, take a look at the problem, suggest solutions and bring along an actual S4000C to show you how it works in person.

Click here for more information on the S4000C Combustible Gas Detector.