The Study On Influence Of Transformation During Catalytic Pyrolysis And Particle Size On Coal Mild Catalytic Gasification

The effects of pretreated methods, particle sizes and gasifying agents on gasification rate and product gas were studied, so as to the transformation of K2CO3during coal char pyrolysis and its effect on catalytic gasification. The fixed-bed reactor and thermal analysis apparatus were used in these experiments. The main results were summarized as follows:The pretreated methods could remove mineral which would cause the inactivation of potassium, these changes had positive impacts on the catalytic gasification. Catalytic gasification reactivity was connected with migration of potassium which was affected by the temperature. The active intermediates were produced through the interaction of K2CO3and coal char, which would promote the gasification reaction. The active intermediate K2-C was introduced to the oxygen transfer mechanism. The mechanism was applied for understanding of the rate and selectivity of the catalytic gasification. The redox processes were verified through experiments.The particle sizes of both catalyst and coal char had impacts on gasification at mild temperature, the effect of catalyst size was more remarkable. The surface area increased with the thinner particle of catalyst, which could generate more reactive sits to promote the gasification reaction.The H2/CO ratio of the synthesis gas could be controlled by changing the H2O/CO2ratio of the gasifying agent. CO2could influence the gasification rate, through competing reactive sites with H2O and influencing shift reaction. The gasification rate was not the simple sum of pure gasifying agent reaction.