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Flashing Liquid Expanders for Two-Phase Pressure Letdowns in Liquefaction Processes

29 Jun 2023
Hydrogen Production, Storage, and Infrastructure Development
Liquefaction of hydrogen is an inherently energy-intensive process. In order to meet the low-carbon goals of green hydrogen as well as make hydrogen economically competitive against other energy sources it is highly desirable to reduce the energy required in the liquefaction process. Single-phase pressure reductions can be accomplished using a radial inflow type turbine to help accomplish these goals but this technology suffers from significant performance and reliability issues when attempting to capture this energy from flashing pressure reductions where both liquid and vapor are present. An axial-flow impulse turbine to reduce the pressure of two-phase flows with high isentropic efficiency and no concerns about reliability or damage to the turbine will be presented. This approach increases the liquid production and reduces the vapor production of the system when compared to the J-T valve base case. Theory of operation and hydrogen-specific case studies are presented. 
Patrick Boyle, Product Development Engineer - Nikkiso