by Colman de Jong
Sales Manager, High-Speed Reciprocating Compressors

Energy companies around the world rely on high-speed reciprocating compressors to meet their gas compression needs. This type of compressor provides economic, flexible and reliable solutions for a wide range of applications in oil and gas resource development. Current industry purchases exceed 2 million horsepower a year.

GE high-speed recips: a solution for every service
To serve the needs of energy industries, GE Energy offers a full line of high-speed reciprocating compressors, ranging from 30 horsepower (22 kW) to 9000 horsepower (6,700 kW), with a variety of piston rod load capacities and frame stroke combinations. Over 10,000 of our compressors can be found around the globe, working in gas boosting, gathering, lifting, fueling and injecting applications - operating 24 hours a day, seven days a week.

A history of continuing improvement
GE Oil & Gas reciprocating compressors date back to 1904, when Nuovo Pignone, now part of GE Oil & Gas, launched a product line which now meets some of the most challenging services in the API618 process industry.

Our product line was further expanded in 1999 with the addition of the Energy Industries and Gemini product lines.

In 2002, it was decided that the technological leadership established by the Nuovo Pignone API618 compressors would be well received by users of all our high-speed reciprocating compressors. A team of industry and compressor design experts was gathered to determine what improvements would provide the greatest benefits for all our users.

Six Sigma provides a framework for technology transfer
Six Sigma is a methodology that continuously defines, measures, analyzes and improves quality throughout GE. When applied consistently in design and manufacturing Six Sigma acts as an enabling process for fully meeting a customer's needs and expectations, creating a culture that supports breakthrough product improvements.

One element in the Design for Six Sigma (DFSS) process is a Quality Function Deployment (QFD) procedure that identifies the customer’s needs and makes customer satisfaction the ultimate goal. Another is the Failure Mode Event Analysis (FMEA), a tool that allows designers and engineers to evaluate potential modes of variance in product quality.

The best of the best: synergies within GE
Led by Paolo Battagli, Reciprocating Compressor Product Line leader for GE Oil & Gas in Florence, and Hamid Sarshar, New Product Introduction leader for the reciprocating team in Houston, the design team developed a list of immediate actions.

The success of the current generation of process compressors is the result of constant technological innovation that draws on the global resources and unmatched experience of GE Energy. For example, the success of the GE ethylene hyper-compressor, rated for continuous duty at delivery pressures up to 3500 bar (50,750 psig), was only made possible by rigorous application of both modern design tools and proven product experience.

By applying these capabilities and technologies throughout the high-speed product line, we are now providing our customers with greater efficiency, reliability, robustness and safety.

DFSS in action: how we made a good thing better
The first product component to be evaluated by the DFSS team was the compressor crankshaft. In the past, some models of the high-speed compressor crankshafts were built with "bolt on" counterweights. During FMEA analysis it was determined that the attachment of the counterweights to the crankshaft was an unacceptable source of variance. As a result, a new attachment method was developed that dramatically reduces the opportunity for variance in the manufacturing and assembly process. Also, as an added benefit to owners of GE high-speed reciprocating compressors, the new components and assembly procedures were developed to fit on our existing fleet of compressors. The final result of this phase of the project was the redesign of the crankshaft, eliminating the "bolt on" counterweights, and utilizing a "single piece" concept with integral counterweights, all machined from a single solid forging. These changes were phased into the product line in 2004.

As the DFSS process continued, product upgrades for the D, E and F series frames were rolled out. The connecting rod was redesigned with new material, the crosshead pin eye was enlarged, and a new method of attaching the connecting rod cap was developed. The crosshead was redesigned with a larger crosshead pin, and the entire assembly was simplified by making the crosshead shoes integral with the crosshead body. Again, to make the benefits of these upgrades available to our existing customers, all of these components were designed to also fit into the existing fleet of D, E and F series compressors.

To identify the new compressor frames, the model series indicators have been modified. The new frames are identified as the DS, ES and FS “Tradition” series of compressors.

The bottom line – lower life-cycle costs
It is a given in natural gas production that field pressures and flows often change, requiring adjustments to compressor capacity and performance. The easier it is to make these adjustments, the lower the associated costs.

For example, many of our compressors feature field replaceable cylinder liners. This means that the cylinder bore can be increased or decreased as your needs change. In many cases, there is no need to modify the on skid piping and accessories, further lowering your cost. Also, in case of damage to the cylinder bore, it takes less money and time to replace a liner than a complete cylinder.

A variety of capacity control devices are also available, including our standard variable volume clearance pockets that feature generous clearance volumes. This ensures that as gas conditions change, horsepower is not wasted, and that the cylinders can be adjusted to balance load your driver to its full capabilities.

Our modular design allows frames and cylinders to be matched and rearranged with only minor changes to the skid. For example, many cylinders will fit on as many as three different frames. Also, cylinders are designed to have identical flange connections. Therefore, inventory levels for idle machinery and spare parts are kept to a minimum.

The difference DFSS makes
The following chart details the capabilities of the upgraded DS, ES and FS frames. The load ratings of the previous D, E and F series of compressor frames are shown in parentheses, for comparison.

Click on chart for larger view