Process optimization and analysis of a novel hydrogen liquefaction cycle

The preliminary designed hydrogen liquefaction plant process based on liquid nitrogen precooling and helium gas turbine expansion refrigeration is firstly modified, simulated and analyzed by Aspen HYSYS. In addition, the multi-parameter optimization of the system is carried out by genetic algorithm (GA) by considering the specific energy consumption (SEC) of the system as the objective function. After optimization, it can be found that the SEC of the system is 7.1329 kWh ka(LH)(2)(-1), which is 19.65% lower than that of base case and the coefficient of performance (COP) and figure of merit (FOM) are 0.1704 and 0.4941, which are higher than that prior to the process optimization. In addition, sensitivity analysis is conducted to present the effects of different operation conditions of the designed process on the features of the hydrogen liquefaction process. Compared with the other two systems of hydrogen liquefaction, the process in this paper shows the best performance. (C) 2019 Elsevier Ltd and IIR. All rights reserved.