What is the power requirement to liquefy hydrogen gas?
1 Comment
Dr. Randall F. Barron
August 1, 2008
The detailed number depends on a number of factors in the liquefaction system design, such as compressor efficiency, expander efficiency, heat exchanger effectiveness, heat transfer from ambient surroundings, etc. A “ballpark figure” may be obtained, as follows.
The ideal power requirement per unit mass for liquefaction of hydrogen gas, staring at ambient temperature (300 K or 80 deg F) and atmospheric pressure (101.3 kPa or 14.7 psia), is (R.F. Baron, Cryogenic Systems, 2nd ed., Oxford University Press, pg. 63, Table 3.1):
For comparison, the actual work requirement for the Air Products & Chemicals, Inc., 60,000 lbm/day hydrogen liquefaction facility at West Palm Beach, FL, is (R.B. Scott, W.H. Denton, and C.M. Nichols, Technology and Uses of Liquid Nitrogen, The Macmillan Co., pg. 54, 79-105):
1 Comment
Dr. Randall F. Barron
August 1, 2008The detailed number depends on a number of factors in the liquefaction system design, such as compressor efficiency, expander efficiency, heat exchanger effectiveness, heat transfer from ambient surroundings, etc. A “ballpark figure” may be obtained, as follows.
The ideal power requirement per unit mass for liquefaction of hydrogen gas, staring at ambient temperature (300 K or 80 deg F) and atmospheric pressure (101.3 kPa or 14.7 psia), is (R.F. Baron, Cryogenic Systems, 2nd ed., Oxford University Press, pg. 63, Table 3.1):
W/m(ideal) = 5167 Btu/lbm = 2.03 hp-hr/lbm = 12, 019 kJ/kg = 3.339 kW-hr/kg = 1.514 kW-hr/lbm
For a figure of merit FOM = 0.25 = W(ideal)/W(actual), the actual power requirement per unit mass would be:
W/m(actual) = 20,700 Btu/lbm = 8.12 hp-hr/lbm = 48,100 kJ/kg = 13.4 kW-hr/kg = 6.06 kW-hr/lbm
For comparison, the actual work requirement for the Air Products & Chemicals, Inc., 60,000 lbm/day hydrogen liquefaction facility at West Palm Beach, FL, is (R.B. Scott, W.H. Denton, and C.M. Nichols, Technology and Uses of Liquid Nitrogen, The Macmillan Co., pg. 54, 79-105):
W/m(actual) = 7.46 hp-hr/lbm = 12.26 kW-hr/kg = 5.56 kW-hr/lbm