Development of a Two-Phase Dense Fluid Expander for Advanced Cryogenic Air Separation and Low-Grade Heat Recovery


Illustration of a state-of-the-art single-phase<br/>DFE unit that is a candidate skid for<br/>retrofit with emerging two-phase DFE technology.
Illustration of a state-of-the-art single-phase
DFE unit that is a candidate skid for
retrofit with emerging two-phase DFE technology.
Air Products and Chemicals, Inc.
Website:  Air Products and Chemicals, Inc.
Award Number:  FE0026186
Project Duration:  10/01/2015 – 09/30/2019
Total Award Value:  $1,095,367
DOE Share:  $876,294
Performer Share:  $219,073
Technology Area:  Gasification Systems
Key Technology:  Air Separation
Location:  Allentown, Pennsylvania

Project Description

Air Products and Chemicals, Inc. (Air Products) researchers will conduct research and a feasibility investigation into using a two-phase dense fluid expander (DFE) to improve the overall efficiency of cryogenic air separation. The first objective of this work is to better understand the limitations associated with two-phase dense fluid expansion from aerodynamic, thermodynamic, and mechanical perspectives. The second objective is to apply this knowledge to construct a prototype device to further explore the basic properties of two-phase dense fluid expansion while collecting primary data for techno-economic analyses. This project will be executed in two phases: Phase 1 will comprise a feasibility investigation of three different applications of two-phase DFEs and, in Phase 2, a prototype device will be designed, fabricated, and tested to further prove the feasibility of commercial applications of DFEs operating in two-phase service.

Project Benefits

Demonstration of this novel concept by Air Products researchers should produce two important process improvements: (1) discharge of the DFE will no longer need to be single phase and (2) the operating region of the current devices will be expanded, thus increasing the degree of power recovery and enabling the implementation of new process concepts. These new process concepts include power recovery from compression waste heat (up to five percent power reduction) and refrigeration extraction by replacing let-down valves with two-phase DFEs (one-to-three percent power reduction). Considering the maturity of cryogenic air separation, these new process options represent a step-change in power reduction and significant savings in operating costs for these units. These new concepts can be applied to existing assets over a wide range of plant sizes; however, they are particularly well suited to large-scale oxygen production by cryogenic air separation and will enhance the economics of producing oxygen for use in coal gasification processes.

Contact Information

Federal Project Manager 
Seth Lawson:
Technology Manager 
K David Lyons:
Principal Investigator 
Scott A. Marchessault:

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