Simultaneous Carbon Capture and Reuse Using Catalytic Membrane Reactor in Water-Gas Shift Reaction

Hydrogen (H2) has been recognized as one of the attractive energy carriers due to its clean and environmentally friendly characteristics where the burning of H2as a fuel produces zero waste emission. Water-gas shift reaction (WGSR) has been accepted as one promising pathway for producing hydrogen. Recently, membrane technology has emerged as a new way to improve high-purity H2production via the WGSR. A substantial amount of research works has so far focussed on the production of H2alone while often neglecting the emission of carbon dioxide ($CO_2$), a greenhouse gas that is known to be the culprit responsible for global warming. Addressing the conflicting issues between clean H2fuel and environmentally adverse$CO_2$emission requires a systematic engineering approach to carbon capture to be incorporated directly into H2production plant. In view of this, the reuse of$CO_2$can be implemented by incorporating the dry methanation reaction. In the proposed reuse strategy, the WGSR uses carbon monoxide (CO) and water as the reactants while the dry methanation reaction uses$CO_2$and methane (CH4) to produce CO and H2. Based on two case studies of industrial plants, this paper presents a rigorous evaluation of the technical and economic feasibility of the implementation of this reuse strategy by using H2selective membrane reactor (MR). Upon extensive analysis of different strategies with and without carbon capture technology, it is found that with the proposed carbon capture strategy, the industrial plants show positive improvement in terms of both technical and economic performances.