Study On Gasification Reaction Activity And Electrochemical Performance Of Coal Conversion Solid Product

The coal conversion processes including coal liquefaction and gasification will produce a large amount of solid by-products with certain recycling value,which contain a lot of minerals and part of unburned carbon.Research on the clean and efficient recycling methods of solid products is of great significance for saving resources,improving the efficiency of coal conversion process and reducing the environmental pollution.In this thesis,the physicochemical characteristics and gasification reaction activity of solid products are studied experimentally for the coal conversion solid products,and the gasification applicability of coal liquefaction solid products is investigated.In addition,porous carbon material is prepared by using gasification fine slag and other carbon-containing raw material as carbon sources.And the as-prepared porous carbon is used as electrocatalysts in the field of electrochemistry,expanding the clean utilization of coal conversion solid products.(1)Research on the gasification reaction activity of coal liquefaction solid products shows that the gasification reaction activity of coal liquefaction solid products is affected by pore structure,carbon structure and gasification temperature.When the gasification temperature is 1300℃,the reaction is out of chemical reaction control,and the influence of external factor on the gasification reaction is weakened.From the perspective of reactivity,coal liquefaction solid products can be used as a raw material for entrained-flow gasification.The optimal ratio of co-gasification of Hami raw coal and coal liquefaction solid products used in experiment is 2:1 according to current study results.The activation energy results show that the co-gasification process at high temperature is mainly affected by pore diffusion.In addition,during the co-gasification process,there is a synergy between coal char and liquefied solid products,which is beneficial to the gasification reaction.(2)Research on the influence of iron-based catalysts during the gasification reaction shows that the effect of wet-loading iron-based catalysts is better than that of dry-loading.The iron-based catalysts can improve the physicochemical structure of coal char,which is beneficial to the gasification reaction.At different gasification temperature,the iron-based catalysts show a certain catalytic effect.As the loading amount increases,the gasification reaction activity increases.However,as the temperature of the gasification reaction increases,the catalytic effect generally shows a downward trend.(3)Research on the electrochemical field of porous carbon prepared from gasification fine slag shows that direct acid etching and ammonia activation can help the gasification fine slag to obtain a developed pore structure and abundant N dopants content.In alkaline media,porous carbon treated with hydrofluoric acid(FS-HF)shows better electrocatalytic performance for oxygen reduction reaction.FS-HF is further used as an air cathode of zinc-air batteries and shows higher power density,excellent charge and discharge stability and larger specific capacity.These results indicate that coal conversion solid products have great potential as high-value electrocatalysts and electrodes for energy conversion and storage.