Comparing exergy losses and evaluating the potential of catalyst-filled plate-fin and spiral-wound heat exchangers in a large-scale Claude hydrogen liquefaction process

Abstract

Detailed heat exchanger designs are determined by matching intermediate temperatures in a large-scale Claude refrigeration process for liquefaction of hydrogen with a capacity of 125 tons/day. A comparison is made of catalyst filled plate-fin and spiral-wound heat exchangers by use of a flexible and robust modeling framework for multi-stream heat exchangers that incorporates conversion of ortho-to para-hydrogen in the hydrogen feed stream, accurate thermophysical models and a distributed resolution of all streams and wall temperatures. Maps of the local exergy destruction in the heat exchangers are presented, which enable the identification of several avenues to improve their performances. The heat exchanger duties vary between 1 and 31 MW and their second law energy efficiencies vary between 72.3% and 96.6%. Due to geometrical constraints imposed by the heat exchanger manufacturers, it is necessary to employ between one to four parallel plate-fin heat exchanger modules, while it is possible to use single modules in series for the spiral-wound heat exchangers. Due to the lower surface density and heat transfer coefficients in the spiral-wound heat exchangers, their weights are 2e14 times higher than those of the plate-fin heat exchangers.