Continuous Pressure SwingAdsorption (CPSA) for Nitrogen Rejection from Natural Gas
Award last edited on: 3/25/02

Sponsored Program
Awarding Agency
Total Award Amount
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Solicitation Topic Code

Principal Investigator
Peet M Soot

Company Information

Northwest Fuel Development Inc

4064 Orchard Drive
Lake Oswego, OR 97035
   (503) 699-9836
Location: Single
Congr. District: 05
County: Clackamas

Phase I

Contract Number: ----------
Start Date: 00/00/00    Completed: 00/00/00
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A continuous pressure swing adsorption (CPSA) process will be developed in Phase I for nitrogen rejection from low quality natural gas. This process will remove the sole techno-economic hurdle for utilizing major resources of low quality natural gas. This will provide a methodology for producing a valuable fuel resource out of gas resources which are currently either being thrown away or are left unused in the geologic formations in which they were discovered. The CPSA process takes the batch operating conditions of traditional PSA and yields a continuous system. The reduction of vessels and simplification of process operation yield significant economic advantages over batch PSA. The planned research should lead to the identification of process parameters which will be the basis for patent submittals. The fundamental concept of continuous rapid cycling PSA has been proven in the laboratory for different product objectives. This CPSA research can build on prior work to rapidly develop a commercial nitrogen rejection process.Anticipated Results /Potential Commercial Applications as described by the awardee:A significant fraction of the Nation's gas reserves are of low quality. This is a resource of over 100 trillion cubic feet of natural gas. It could solely provide the entire Nation's domestic natural gas production for up to 10 years. This nitrogen rejection process also provides economic and environmental benefits. It is economically competitive, and it will capture and use the methane (a greenhouse gas) emissions which are now going into the air from coal mines.

Phase II

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Start Date: 00/00/00    Completed: 00/00/00
Phase II year
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Nitrogen rejection continues to be the major technological and economic hurdle for producing pipeline quality gas from low-quality gas resources. Numerous types of processes have been proposed for nitrogen rejection, but pressure swing adsorption is one of two that have been technically demonstrated. Unfortunately, it has not been proven economically competitive. This project involves exploration of the technical and economic viability of a continuous pressure swing adsorption (CPSA) process. In Phase I, it was demonstrated that activated carbons (AC) and zeolites can effect the desired separation of nitrogen from methane. A significant discovery during Phase I was that 4A zeolites exhibited nitrogen selectivity in the process because of the kinetics of nitrogen versus methane adsorption. This provides the potential option of using either a methane-selective adsorbent, AC, or a nitrogen-selective adsorbent, 4A zeolite, in the CPSA process. Even though the simple CPSA cycle is constrained in its upgrading capabilities, the addition of process engineering unit operation enhancements provides the potential for upgrading a wide variety of sub-quality gases to pipeline quality natural gas. In Phase II, a demonstration plant will process 300 MCFD (thousands of cubic feet per day) of feed gas, which at this small scale, can cost less than one dollar per MCF of product. The building of a larger plant, capable of producing three million cubic feet per day of pipeline gas, could have a processing cost of only $0.48/MCF of product.Anticipated Results/Potential Commercial Applications as described by the awardee: The Nation has nearly 250 trillion cubic feet of sub-quality natural gas. Successful development of this process should provide economic, national security, and environmental benefits. Cost estimates show that this process can provide gas at lower prices than current levels and uses a domestic resource. Environmental benefits also arise from the capture of methane, a greenhouse gas.