Greener process for syngas cogeneration: Bi-reforming of methane coupled with chemical looping combustion

A greener, self-sustainable and integrated process has been proposed in this paper to produce syngas through chemical looping combustion (CLC) coupled bi-reforming of methane (BRM) with CO₂ for the first time_. The proposed process scheme is advantageous in several folds, that is, it consumes two major greenhouse gases, overcomes the drawback of catalyst deactivation caused by coke formation and it can produce syngas gas with an H₂/CO molar ratio of 2 as required for methanol synthesis processes. Further, integration of BRM with CLC, helps to fulfil the endothermic heat demand and CO₂ feed requirement of BRM. Further, the process is made self-sustainable with the incorporation of heat recovery and steam generation and power generation sections. Steady-state plant-wide models have been developed for the proposed integrated CLC-BRM process using ASPEN Plus software and detailed thermodynamic analysis has been performed. Rigorous sensitivity analysis has resulted in 98.2% CH₄ conversion, H₂ and CO yields of 93.6%, 93.9% respectively with a syngas ratio of ≈ 2 at the bi-reformer conditions of 850°C and 1 atm. The optimal steam and CO₂ input flowrates for bi-reforming of 1 kmol/hour CH₄ are found to be 0.8 and 0.4 kmol/h respectively, which are fulfilled by CLC integration. The performance of the proposed scheme is further compared with a conventional bi-reforming process that uses a combustor for energy supply. The results demonstrate the feasibility and potential pay-offs of the CLC-BRM scheme in terms of increased energy efficacy and eco-friendliness.