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
Geir Skaugen, David Berstad, Øivind Wilhelmsen
Abstract
Detailed heat exchanger designs are determined by matching intermediate temperatures\nin a large-scale Claude refrigeration process for liquefaction of hydrogen with a capacity of\n125 tons/day. A comparison is made of catalyst filled plate-fin and spiral-wound heat exchangers\nby use of a flexible and robust modeling framework for multi-stream heat exchangers\nthat incorporates conversion of ortho-to para-hydrogen in the hydrogen feed\nstream, accurate thermophysical models and a distributed resolution of all streams and\nwall temperatures. Maps of the local exergy destruction in the heat exchangers are presented,\nwhich enable the identification of several avenues to improve their performances.\nThe heat exchanger duties vary between 1 and 31 MW and their second law energy\nefficiencies vary between 72.3% and 96.6%. Due to geometrical constraints imposed by the\nheat exchanger manufacturers, it is necessary to employ between one to four parallel\nplate-fin heat exchanger modules, while it is possible to use single modules in series for the\nspiral-wound heat exchangers. Due to the lower surface density and heat transfer coefficients\nin the spiral-wound heat exchangers, their weights are 2e14 times higher than\nthose of the plate-fin heat exchangers.