Thermodynamic analysis of a net-zero emission system for multi-generation of power, cooling, heating, and methanol with methane looping reforming

Methane looping reforming to produce syngas is an alternative to partial methane oxidation because it allows for better control of the oxidation reaction and safely separates oxygen from syngas. However, most systems are monofunctional and lack the cascading utilization of energy flows, resulting in significant exergy loss. This study proposes a novel net-zero emission system that utilizes methane looping reforming for multi-generation of electricity, heating, cooling, and methanol. The reduction of high-valent manganese oxides by decoupling the partial oxidation reaction of methane into an Mn-based oxygen carrier redox cycle yielded products with H2/CO ratios suitable for methanol synthesis, resulting in approximately 100% CH3OH conversion rate. The oxidation of low-valent manganese oxides provides high-temperature heat for heat recovery, and the lithium bromide refrigeration section produces domestic hot and cold water as by-products. The proposed system reaches 77.1% and 65.7% energy and exergy efficiencies, which are 1.04- and 1.61-fold higher than those of traditional partial oxidation systems, respectively. Our research presents a new system integration concept that enables the efficient and controllable loop reforming of methane for methanol production.