Oxygen-hydrogen combustion power generation is expected to be an effective power generation technology for reducing carbon dioxide emissions. Oxygen-hydrogen combustion power generation requires high-pressure, high-purity oxygen; however, the oxygen up to 100~150 bar consumes a significant amount of energy, resulting in a low net thermal efficiency. We analyzed the effect of energy saving in high-pressure oxygen production by cryogenic air separation using low-temperature heat of liquid hydrogen. Compared to conventional cryogenic air separation, oxygen compression power is reduced by 99 ~ 97 % by a liquid phase oxygen compression after the low-pressure distillation column. As a result, specific energy consumption is reduced by 0.184 kWh/Nm3 at 100 bar oxygen (97 % purity). Furthermore, using oxygen-enriched air (30 % O2 content) specific energy consumption can be further reduced by 0.089 kWh/Nm3 at 100 bar oxygen.
Doi et al. (Wed,) studied this question.