Research On Pyrolysis And Carbothermal Reduction Of Pyrolusite Based On Microwave Heating Linear Metal-Enhanced Coal Briquette

The direct combustion of pulverized coal has a low heat utilization rate and serious pollution.The compression and solidification of coal briquette is of great significance for its subsequent efficient and clean utilization.In order to explore the effective method of clean coal classification and quality clean utilization,this paper carried out research based on microwave heating linear metal-strengthened coal pyrolysis and carbothermal reduction of pyrolusite.The main contenes and conclusions were as follows:The microwave pyrolysis experimental device was used as the platform to study the effect of iron,aluminum and copper linear metal types and lengths on the weight loss rate and product distribution of coal briquette at a microwave power of 320 W and a time of 15 min.Test the properties,grasp the quantitative relationship between the main properties of coal briquette charcoal and metal length,and determine the optimal metal type and length.The results show that,the length of the same linear metal was increased,the weight loss rate of the coal briquette was increased,the yield of tar yield of and coal oven gas were creased.The metal length is the same,the pyrolysis effect of metal iron reinforced coal is better than metal aluminum and metal copper.Pyrolysis coal briquette charcoal had good physical and chemical properties Metal iron with a length of 10 cm was the best linear metal type and length.Under this condition,the weight loss of coal briquette was 47 wt.%,The yield of tar was 26 wt.%,And the yield of coal oven gas was 16 wt.%.The yield of coal briquette charcoal was 52 wt.%,And the anti-dropping rate and water absorption rate of coal briquette charcoal were 99.23 wt.%and 37.12 wt.%,respectively.The thermogravimetric analyzer was used to perform pure oxygen combustion and carbon dioxide gasification experiments on the pyrolysis coal briquette charcoal within a temperature window of 50-900?.The thermodynamic parameters of combustion,such as ignition temperature,burnout temperature and ignition index,were obtained.The relationship between gasification reactivity and pyrolysis conditions was studied.The kinetic analysis of coal briquette charcoal combustion and gasification reaction was carried out to reveal the laws of coal briquette charcoal combustion and gasification reaction.The results of combustion characteristic analysis showed that the length of the same metal increases,the ignition temperature and burnout temperature of the coal briquette charcoal increase,the ignition index decreases,the combustion performance becomed worse,the reaction intensity becomes weaker,the activation energy increases,and the reaction activity becomes worse.The combustion temperature and activation energy of 4 cm copper reinforced coal briquette charcoal were 279?,51.47 kJ/mol,and the pre-index factor was 468.5 min-1.Therefore,the combustion reactivity was the best,and the ignition was easy and the combustion performance was the best.The combustion reaction of coal briquette charcoal conforms to the first-order reaction law,and there was a kinetic compensation effect,and the compensation coefficient had nothing to do with the pyrolysis conditions.The analysis results of gasification characteristics show that the gasification reaction of coal briquette charcoal conforms to the n=2/3 unreacted shrinking core model.As the length of the same metal increases,the temperature value T0.5 corresponding to the conversion rate of integral carbon to 50%increases,the activation energy and pre-finger factor increased,and the reactivity becomes poor.Dynamic compensation effect exists in coal briquette charcoal gasification reaction,the compensation factor has nothing to do with the pyrolysis conditions The coal briquette charcoal gasification reaction T0.5 was 777.91?,and the activation energy was 67.54 kJ/mol,and the gasification reactivity was the best.Used the coal briquette charcoal as a reducing agent,the coal briquette charcoal was crushed and mixed with pyrolusite to form a uniform press,and the linear metal coupling microwave carbothermal reduction of pyrolusite experiment.The reduction effect of pyrolusite was quantitatively evaluated with manganese leaching rate as the index,and the influence of linear metal species and length on manganese leaching rate was studied,so as to preliminarily reveal the mechanism of the reduction reaction process.The results showed that,under the condition of the same reducing agent and metal type,the linear metal length increases and the leaching rate of manganese increases.When the length of the reducing agent and the metal are the same,the effect of metal iron on strengthening carbon thermal reduction was better than that of metal aluminum and metal copper.When the length of 10 cm copper coal briquette charcoal was used as reducing agent,and the embedding length of 10 cm iron was used,the leaching rate of manganese was 97.2 wt.%,and the reduction effect of pyrolusite was the best.The linear metal embedded in the microwave field strengthens the microwave selective heating,promotes the circulation of both the reduction reaction and the gasification reaction,and strengthens the reduction effect of pyrolusite.