The evaluation of a methane autothermal chemical looping reforming experiment based on exergy analysis

Abstract

Compared with a double circulation fluidized bed, an internally circulating reactor (ICR) has a wider pressure range, thereby increasing the conversion efficiency of methane and reducing the cost. However, since the ICR is a new reactor, there is a lack of detailed analysis and research on the internal processes inside the reactor. Consequently, in this paper, a detailed exergy analysis and an advanced exergetic analysis are utilized to evaluate a methane autothermal chemical looping reforming experiment carried out on an ICR. A detailed analysis of the internal exergy destruction of the ICR is carried out by establishing a mathematical model for the enthalpy and exergy of the substance. The exergy destruction inside reactors is divided into the exergy destruction in the chemical reaction process, the destruction of thermal exergy and other flowing exergy destruction. The influences of the CH4/NiO molar ratio and addition of steam or not on exergy destruction are studied. With the increase of CH4/NiO molar ratio, the chemical looping reforming process gradually supersedes the chemical looping combustion process and becomes the dominating reaction, which exerts a strong beneficial influence on the reduction of exergy destruction of chemical reactions. When the CH4/NiO molar ratio is 0.60, the exergy efficiency of the product is up to 52.17%. The advanced exergetic analysis provides a direction for improving the experiment. Based on these results, the ICR is evaluated in all aspects, including comparative evaluation, existing limitations, and possible future work.