The goal of the Advanced Reciprocating Compression Technology (ARCT) program is to create the next generation of reciprocating compressor technology to enhance the flexibility, efficiency, reliability, and integrity of pipeline operations. The suite of technologies developed by this program will substantially improve the current infrastructure by offering increased capabilities to enhance pipeline throughput capacity and reliability of gas delivery to consumers.

Southwest Research Institute (SwRI) – Project management and research activities

Gas Machinery Research Council (GMRC) and supporting member companies – Cost share, participation as industry advisors and as industry support for research focus and testing

Location: 
San Antonio, TX 78238

Advances in compression technology helped the U.S. gas industry expand after World War II. The original first generation compression infrastructure consisted of many small slow-speed (180 rpm) compressors that moved gas from producing regions to markets. To provide the necessary expansion, the development of a second generation with “larger, higher-speed” machines promised a significant reduction in installed cost. As industry installed the first machines, they experienced many reliability and operational problems. Analog pulsation control was employed to help solve these problems. This second generation of compression technology has now become known as “slow-speed integral” compression. At three times the horsepower, running at twice the speed of the equipment it replaced, these machines have been the compression technology most utilized for the past 50 years. With pulsation problems under control, this compressor technology has built a long record of reliability, ruggedness, and long life, with high efficiency. Compressor stations consist of many individual machines, and the primary method of capacity control is to activate a different number of machines.

The promise of dramatic cost reductions has driven the industry towards even higher speed, larger horsepower reciprocating compression, powered by efficient separate modern gas engines or large electric motors. Within the last few years, the first vintage of this new class of machines has been installed. This third generation of equipment is four to five times the power of the prior generation and is now running at two to three times the speed. This technology brought about new vibration and pulsation problems. The pipeline industry faces a technology transition similar to 50 years ago.

As a few large machines replace many small machines, each machine must provide a wider capacity range and increased reliability. Varying speed more widely complicates pulsation control, and higher speeds have resulted in significant losses in compressor-efficiency, contributed in part by both pulsation control and conventional valve technology. This high-speed compression requires advancements in technology to meet its full potential and to address the pipeline industry’s compression needs.

The intelligent compression technology to be provided by this program will be comprised of many active and adaptive subsystems that can automatically be tuned to off-design operating conditions. The ARCT program will advance the technology in five specific areas: pulsation control, capacity control, valves, sensors and automation, and systems integration.  

Reciprocating compressors are a critical element of the U.S. pipeline’s compression mix, but current options all require compromises – in cost, efficiency, capacity, reliability, or a combination of these. The ARCT program could compel the U.S. pipeline industry to realize the great benefits of reciprocating compression (flexibility, efficiency) with less compromise.

The ARCT program has taken the first step toward the next generation of reciprocating compressor technology, enhancing the flexibility, efficiency, reliability, and integrity of pipeline operations. The technologies developed by this program could eventually provide pipeline operators with improved choices for new compression and innovative products that can be retrofitted to existing machines. The development of these advances could substantially increase compression efficiency and increase overall natural gas throughput capacity from existing and new compression systems, enhancing the reliability of natural gas delivery from the infrastructure.

Results:
During the course of this one-year project, a number of critical needs were identified and eighteen technology solutions were initiated. These technologies have been matured to a proof-of- concept stage. The GMRC PSC has recommended advancing half of these technologies to the next stage under separate funding.

The program has initiated development of technology solutions to address the current limitations of modern high-speed compression, thus enabling this equipment to meet its full potential. If this does indeed occur, the ARCT program will meet its stated objective of creating the next generation of reciprocating compressor technology that provides added pipeline flexibility at reduced capital cost.

Most of the currently installed fleet of pipeline reciprocating machines are slow speed integral compressors. Almost all new reciprocating machines are large-horsepower, high speed compressors. It is, therefore, imperative that any meaningful solutions must address both classes of machines.

The objective of this program was to initiate efforts toward creation of the next generation of reciprocating compressor technology for both classes of machinery. It is believed that the preliminary developments under this program represent significant initial efforts toward accomplishing the following goals for the next generation of compression:

• Improved flexibility (50% turndown)
• Improved efficiency (90%)
• Improved reliability (order of magnitude increase in valve life with half of the pressure drop)
• Improved integrity (vibration less than 0.75 IPS)
• The ARCT program has proven the concept of a number of enabling technologies that have the potential to meet these ambitious goals.

Retrofit technologies that address the challenges of slow-speed integral compression are:

• Optimum turndown using a combination of speed and clearance with single-acting operation as a last resort.
• If single acting is required, implement infinite length nozzles to address nozzle pulsation and tunable side branch absorbers for 1x lateral pulsations.
• Advanced valves, either the semi-active plate valve or the passive rotary valve, to extend valve life to three years with half the pressure drop.

This next generation of slow-speed compression should attain 95% efficiency, a three year valve life, and expanded turndown. New installation technologies that address the challenges of large-horsepower, high speed compression are:

• Optimum turndown with unit speed.
• Tapered nozzles to effectively reduce nozzle pulsation with half the pressure drop and minimization of mechanical cylinder stretch induced vibrations.
• Tunable side branch absorber or high-order filter bottle to address lateral piping pulsations over the entire extended speed range with minimal pressure drop.
• Semi-active plate valves or passive rotary valves to extend valve life to two years with half the pressure drop.

This next generation of large-horsepower, high-speed compression should attain 90% efficiency, a two-year valve life, 50% turndown, and less than 0.75 IPS vibration. The potential to attain these next generation goals are within the industry’s reach if the identified technology concepts are fully matured to commercially available products and service during the next stage of development.

All activity under this project has been completed.

$650,000

$350,000

NETL – Richard Baker (richard.baker@netl.doe.gov or 304-285-4714)
SwRI – Danny Deffenbaugh (ddeffenbaugh@swri.org or 210-522-2384)

Final Report  [PDF-7418KB] - December 2005

Gas Machinery Conference 2005 Presentation - Power Point Presentation [PPT- 29.4MB] available by request

Technology Status Assessment  [PDF-187KB]

Project Announcement Press Release [PDF-77KB] - December 2004

Gas Machinery Journal article [PDF-3331KB] - March 2005 - GMRC Awarded DOE Contract