On the optimum conditions in an isenthalpic liquefaction process

Summary

Two criteria for optimum conditions in isenthalpic liquefaction processes are discussed. The first criterion treated is that of maximum yield of liquid per unit of gas compressed. This well-known criterion leads to conditions corresponding to the inversion curve. The second criterion discussed is that of maximum yield per unit of energy expended. This criterion is evaluated and it is shown that it leads not only to greater efficiency, but also to working pressures that are considerably lower than those deduced from the first criterion. It should be noted, however, that in engineering practice often neither of the two criteria is applicable because of technical or economical limitations set to the working pressure.