New technologies for gas operations

Pipeline & Gas Journal, June, 2002

According to industry projections, to meet the demand for natural gas in 2020, more pipelines need to be constructed and, perhaps more important, the integrity and safety of the existing pipeline infrastructure needs to be effectively maintained and enhanced.

At Gas Technology Institute (GTI), these needs propel a wide range of research and development activities to benefit the natural gas industry and its customers. Working with government agencies, gas companies, and industry organizations. GTI researchers are developing low-cost solutions to some long-standing concerns. And cutting-edge sciences--in fields such as fiber optics, biotechnology, and microelectronics--are being employed.

Fiber Optic Pipeline Encroachment System

Natural gas transmission companies mark the right-of-way areas above buried pipelines with warning signs to prevent accidental third-party damage. Nevertheless, pipelines are sometimes damaged by unauthorized construction equipment. In fact, third-party damage is by far the chief cause of pipeline damage.

Working with Nicor Gas, as part of a U.S. Department of Energy (DOE) program, GTI is developing an optical fiber intrusion detection system that will prevent outside force damage by sensing when construction equipment is near a pipeline. Upon detection, the system would automatically initiate alarms and notifications to pipeline operators.

The concept involves burying a long optical fiber, similar to those used in telephone systems, above the underground pipeline. Periodically, light pulses are sent down the optical fiber. When construction equipment is present, the weight and size of the equipment causes the optical properties of the fiber to change, and some of the light is reflected back to the source, where it is detected. The location of the equipment is determined by measuring the time for the reflected light pulse to return.

"We believe it is possible to monitor several miles of pipeline from a single location," notes GTI Assistant Institute Physicist Jim Huebler, who is managing the project. "This effort will develop methods of distinguishing harmful equipment from benign interferences, such as pedestrians and mowing equipment."

Alerting a pipeline company that construction equipment is moving close to its pipe permits immediate action to stop unapproved excavation and potential damage to the pipeline. The system will be designed to provide real-time policing of pipelines, 24 hours a day, seven days a week.

Microbial Inhibitor to Control Internal Pipeline Corrosion

In a project to control the affect of microbially influenced corrosion (MIC) on natural gas pipelines, researchers are investigating the use of natural chemical compounds isolated from plants for preventing, mitigating, or eradicating corrosion due to microbial activity inside metal (iron and stainless steel) pipes.

"Agents exist in nature that inhibit some or all of the steps executed by microorganisms in the formation of biofilm, a prerequisite for the initiation and production of microbially influenced corrosion," explains project manager Bob Paterek (GTI Manager, Environmental Biotechnology). "Our approach is to evaluate natural products for their abilities to block the attachment, physiology, or reproduction of microbial agents."

The first natural product to be tested is the oil that can be extracted from the seeds and pods of pepper plants. The ultimate project goal is the development of a commercially viable, environmentally friendly agent that helps to control MIC.

Work is focusing on developing information on effective concentrations, environmental impacts, production methods, and commercial application methods.

Capacitive Tomography for Pipe Location

Throughout the gas industry, the accurate subsurface imaging of buried plastic and metallic objects has been a prime interest because of the cost, reliability, and safety concerns associated with making inappropriate excavations. In response, GTI is developing a compact and inexpensive capacitive tomography imaging sensor that takes the form of a flat plate or flexible mat that can be placed on the ground to create an image of objects embedded in the soil. In addition to its application as a stand-alone imaging sensor, the thin-film sensor might also be applied to the surfaces of digging and boring tools to detect obstacles.

The technology would improve the accuracy and reliability of any operation that involves excavation by locating and avoiding buried objects.

Ground-penetrating radar has been used for pipe location with varying success, partly because radar requires a high-frequency carrier to be injected into the soil. The higher the frequency the greater the resolution of the image. However, high-frequency radio waves are more readily absorbed by soil. Also, high-frequency operation raises the cost of the associated electronics. By contrast, the capacitive tomography sensor uses low frequencies with a multiple-element antenna to obtain better resolution. This low-frequency operation reduces the electronics cost while improving depth of penetration.