Comparison of several pre-combustion decarbonisation routes for hydrogenproduction from methane

摘要

The efficiencies, expressed as a function of CH_4 to electricity conversion, of four sorption-enhanced (SE) techniques for pre-combustion decarbonisation are compared for three different sorbents. The spread in efficiencies after some optimisation of design layout for SE-SMR (steam reforming of methane) and SE-ATR (autothermal reforming) was from 51.6 to 52.6% depending on the sorbent chosen. This is rather surprising when considering the differing operational requirements of these sorbents. The total amount of steam used in the cycle (both for the steam reforming and regeneration) was the most critical parameter in determining overall efficiency. As the total steam requirement is increased efficiency drop slowly. At a certain point, the efficiency starts to drop much more rapidly. At this point the amount of steam in the steam cycle is not enough, and extra steam has to be created. Operation in a regime where this extra generation can be avoided is highly desirable.