ReaxFF MDSs-based studies on gasification of glucose in supercritical water under microwave heating

Abstract

It is shown that ReaxFF molecular dynamics simulations (MDSs) can be used to study the high temperature gasification of glucose in supercritical water under microwave heating. At the early stage of gasification, yields of gas products have great difference under microwave and conventional heating models. It is considered that the difference results from the non-thermal effect of microwave. Therefore, simplified pathway model of free radical reactions is further constructed to study the influences of external electric fields on the yields of hydrogen gas, carbon monoxide and intermediate formaldehyde. Rotation characteristics of water and carbon monoxide electric dipoles are also studied at a high temperature. To analyze the impacts of external electric fields on the water-gas shift reactions, collision theory is introduced and several simplified collision models are constructed and detailed. Based on our studies, for the first time, it is concluded that using microwaves as heating source is feasible to the gasification of glucose in supercritical water, where no obvious thermal runaway is found. Moreover, the external microwave can increase the production of hydrogen gas through promoting the yields of glucose decomposed into formaldehyde and hydrogen free radical.