Gas Processors Suppliers Association - Since 1928, GPSA has grown to an organization of about 350 companies engaged in meeting the supply and service needs of the natural gas and gas processing industry.

Although GPA research extends back to the organization's beginnings in the 1920's, the current formal research program was developed in the early 1960's to meet the technological needs of a rapidly expanding industry. The program was structured as a cooperative effort, funded primarily by the members of the organization, with contributions from other interested parties. This program has received worldwide recognition and has served as a model to other cooperative programs.

The cooperative approach has proved to be practical, economical, and efficient, principally by eliminating needless duplication of individual company research. Furthermore, experience has shown that GPA research projects have stimulated additional research by other organizations and by individual companies, so that total benefits accruing to the industry go substantially beyond the results obtained from the cooperative projects.

GPA has had an outstanding history of predicting/determining the most pressing needs of the industry and pursuing relevant research. The GPA philosophy has been to sponsor accurate measurements on a limited number of simple systems to allow development of reliable correlations that can predict needed properties.

The ultimate objective of GPA experimental research and theoretical studies is to provide the practicing engineer with the information needed to predict, quickly and accurately, the physical and thermodynamic properties of complex hydrocarbon systems. From these predictions are calculated the heat loads, flow rates, equipment sizes, product recoveries, investment costs, and ultimately the economic success or failure of an operating facility. The dollars invested in the research represent only a minute portion of the returns to the industry in the form of efficient and economical facility design.

There are three principal ways to define basic thermodynamics properties for a given mixture at given conditions. The simplest and least expensive way is to predict them by means of a reliable computational method or correlation. If confidence in the available data or computational method is low, a more complex and expensive way is to measure them in the laboratory. The worst way is to determine them from an operating plant, which can result in exorbitant expense if the data or computational method used for design is wrong. GPA research strives to provide experimental data to allow accurate predictive correlations, avoiding the expense of over or under designed facilities.

History

Prior to the inception of the cooperative GPA research program in the early 1960's, much of the available thermodynamic data for light hydrocarbons had been derived from a small amount of experimental data. The data that was available was further limited to pure components, although engineering designs almost exclusively involved hydrocarbon mixtures. Since these mixtures did not behave in a manner consistent with predictions based on pure component behavior, facilities were often improperly designed, resulting in capacity problems or excessive costs.

First efforts of the GPA cooperative research involved evaluation and refinement of K value charts based on the Hadden convergence pressure concept. This information was published in 1955. Following some revisions, in 1957 these charts were programmed for use on a computer. In 1960, the Chao Seader correlation was published, and an attempt was made to revise the K value curves based on this correlation in addition to other available correlations. While the Chao Seader correlation avoided some of the problems of the convergence pressure concept and accounted for aromaticity and compositional effect, it was unsuitable for graphical presentation because of its many variables. Also, it had a relatively low pressure limit.

An effort was initiated to support a correlative study, the object of which was to develop a set of ideal K values suitable for chart presentation using only two variables - pressure and temperature. Considerable effort and funds were channeled into this study. However, as the work progressed, it became apparent that the lack of accurate data in certain critical areas posed a serious handicap to any significant improvement in correlation accuracy. Better correlations would require more accurate data.

At this time, process engineers were faced with using sparse data for both phase behavior and enthalpy. No new enthalpy data had been published in 30 years. A great deal of trial and error went into facility design. This led to the decision in 1961 to undertake comprehensive experimental programs to acquire thermodynamic data for several light hydrocarbon systems in the C1-C10 range. The magnitude of the problem was such that it was determined to separate the duties and assign them to two different steering committees - one for phase equilibria and one for enthalpy.

From this point, the development of the enthalpy and K value data followed two separate but parallel paths. Each program has been guided by a small steering committee of industry experts. The efforts of both committees are directed toward the single purpose of generating accurate and consistent thermodynamic design methods.

Research in the 1960's was also directed toward market development. One of the market development projects was the technological development of LP Gas engines. Due to GPA efforts, a significant step forward was made in 1963 when the adoption of motor fuel grade propane (HD-5) specifications gave engine manufacturers a standard fuel around which engines could be designed. An engine research program conducted by the Ethyl Corporation, sponsored in part by GPA, was the first to determine the performance and economics of LP Gas as a fuel in commercial engines and provide comparisons to other available fuels. Although LP Gas has achieved limited use in engines, the passage of the Clean Air Act of 1990 has once again opened the door to the potential of a significant market.

This brief recap of early GPA research makes one realize how far the gas processing industry has progressed technologically - largely through the efforts and funding of GPA member companies. Over the last forty years a vast amount of data has been collected, leading to greatly improved predictive models.

Overview

GPA's cooperative research has provided an effective and efficient means of:
• Identifying and assigning priorities to the industry's data needs.
• Auditing, compiling, and evaluating available data and computational methods.
• Designing and supervising experimental measurements of thermodynamic properties on a systematic basis.
• Providing the computational tools for accurate and economical design of light hydrocarbon process ing facilities.

The GPA research effort is guided by a number of common sense principles:
• Research must concentrate on areas of critical importance to the gas processing industry.
• Research must be directed toward problems where solutions are considered possible.
• The economic value to the industry must be evaluated in advance.
• Projects must avoid areas of a proprietary nature or where patents would create problems.

The practical achievements of the GPA research program are evident in the list of published results - "GPA Research Reports" - included in this brochure. Examination of this list will reveal a wide range of research investigation into virtually every area of natural gas treating and processing. This data forms the basis of most process simulators used in the gas processing industry.

The success of the program is directly attributable to the members of the two Technical Section F Sub-groups who oversee the projects. These people are highly knowledgeable of the problems faced by the industry and of the availability (or lack) of data to help resolve those problems. Their unique in depth knowledge - both theoretical and practical - of data and process makes them proficient in the guidance and evaluation of the research. In addition to the individual knowledge each brings, the synergistic interchange of ideas among the committee participants results in excellent supervision and assessment of the ongoing research, insuring that GPA member companies receive the maximum benefit for the funds they are contributing.

The member companies who donate their employees' time and the individual committee members who frequently end up donating their own time to accomplish this work are greatly appreciated.

Funding Leverage

Of great importance, but often overlooked, is the added value gained through co funding from other organizations, partial subsidization by the research contractors, and the extension of GPA research by other organizations. The funds appropriated by GPA members have been multiplied many times over through these means. GPA recognizes and appreciates the contributions over the years of organizations such as the American Petroleum Institute (API), the Propane Gas Association of Canada (PGAC), the Gas Technology Institute (GTI), the National Propane Gas Association (NPGA), the Propane Education Research Council (PERC), and the Gas Processors Suppliers Association (GPSA).

GPA is pleased with GPSA's $25,000 annual grant that will go into projects to update and maintain the GPA Database and the GPSA Engineering Data Book.

Technical Section F

Chairman: Dan McCartney, Black & Veatch, Overland Park, KS
Mike Hegarty, H2W United LLC, Littleton, CO
Dr. Ben S. Ho, BP, Houston
Jame Yao, IPSI, Houston
Sverre Overra, Norsk Hydro, Oslo, Norway
Al Goethe, Washington Group International, Houston
Dr. Cal Spencer, KBR, Houston
Scott Northrop, ExxonMobil, Houston

Chairman: Dr. Karl Gerdes, Chevron, Richmond, CA
Dr. Mark Johnson, BP, Houston
Dr. Gerhard Lauermann, Linde Engineering Division, Germany
Dr. Havard Lidal, Statoil Hydro ASA, Oslo, Norway
Craig Schubert, Dow Chemical Co., Freeport, TX
Chris Root, Duke Energy Field Services, Denver
Raymond French, Shell Global Solutions (U.S.) Inc., Houston
Johnny Johnson, Washington Group International, Denver
Kindra Snow-McGregor, Washington Group International, Denver
R.J. Lee, ExxonMobil, Houston, TX

Authorization and Funding Procedures

Adequate and equitable funding, with a rigid approval procedure and continuing oversight, are key elements in the impressive accomplishments of the GPA research program. The following schematic of the approval and funding procedure illustrates the direct and continuing involvement of technical specialists in project conception and supervision. It depicts the active participation of industry management in the budget process, and the final expenditure authorization by each member company.

Details of the authorization and funding procedure may be summarized as follows:

1. Research proposals usually originate in one of the two Sub-groups of Section F (Technical Data Development) or other Working Sections of the GPA Technical Committee. The Sub-groups are made up of research engineers and other technical specialists. Other Technical Sections are manned by appropriate experts appointed by member companies. The responsible Sub-group or Section will outline a research schedule for a suitable project and recommend a level of funding to be incorporated in the general research budget.

2. Project proposals are submitted to the Technical Committee for general endorsement. The Technical Committee represents all phases of GPA technical interest and thus provides an appropriate screen to insure projects of specific need and broad industry application.

3. The proposal next goes to the Board of Directors, which must approve the project by a 75% majority of those present at the meeting. Board approval simply authorizes the project to be placed on the research ballot that is submitted to the individual member companies.

4. Final authorization of a project is granted by member companies who vote individually on each separate project. The votes of production based member companies are weighted by their gas liquids production. For approval, a project must receive a favorable vote from companies owning 75% of the total production used in calculating annual GPA dues (the dues base); however, non-production based funds for a project will be included in the calculation by converting dollars donated to "psuedo-gallons". The conversion is based on the previous year's ratio of dollars to gallons. Non-production based companies that donate funds in this manner can contribute on a general or a project by project basis. A minimum of 50% of gallons from production based members is still required to pass a project, regardless of the level of funding from non-producers. Companies are assessed in accordance with the proportion their production represents to the total production of all companies approving the project.

5. Failing to get 75% favorable vote, a project can still obtain approval through a supplemental ballot to those companies originally voting in favor of it. Those companies that approve the project on the supplemental ballot will be assessed for support of the project in the proportion that their production represents to the total production of all approving companies.

6. Following member company approval and assured funding of a project, the originating Sub-group or Technical Section develops a detailed Request for Proposal which defines the problem, outlines work needed, and specifies funds available. Generally, proposals are solicited from all investigators and research organizations known to have facilities and interest appropriate to the proposed project.

7. Selection of the project investigator is made by the responsible Sub-group or Technical Section, and a contract is awarded. The Committee designates a project coordinator who works directly with the investigator and exercises oversight responsibility for the duration of the project. The project coordinator keeps the Committee informed on project progress, problems, and budgetary compliance. Section F and the Technical Committee is charged with the responsibility of terminating a project if the contractors are not performing adequately.

Results of most of the GPA sponsored research projects since 1971 have been published as numbered Research Reports and are available upon request.

GPA Research Program Sponsors - **$15.00
GPA Research Program Non-Sponsors - $500.00
University Libraries - $30.00

*Prices include free shipping within the Continental US (lower 48 States). Call (918-493-3872) or email (gpa@gasprocessors.com) GPA for shipping outside this area.

**The definition of a GPA Research Program Sponsor is a company that is currently a sponsor of the program at the time of ordering the publication (view the current Participating Companies in this Adobe file).