Waste Heat Recovery System through Methanol Steam Reforming with Absorption Heat Pump

Abstract

Through the methanol steam reforming (MSR), the energy of low temperature waste heat (100-150°C) can be recovered into that of hydrogen. However, actual MSR requires over 200°C to enable the high conversion of methanol into hydrogen in terms of reaction kinetics. Thus, in this research, a waste heat recovery system through MSR with absorption heat pump (AHP) was proposed. The role of the AHP is to enhance the temperature level of the waste steam up to 230°C, which is used for the MSR. The endothermic reaction of the MSR decreases the temperature of the MSR reactor. Therefore, high temperature steam should be used not only for the MSR reaction but also for heating the MSR reactor. To evaluate the performances of the system, "enthalpy enhancement factor" was defined. As a result, the recovered enthalpy of the waste heat was almost 4.5 times as much as the required work for the AHP when the waste heat temperature was 150°C and S/C ratio was 4.0.