Experimental Study On Catalytic Gasification Of Ceramsite Pine By Ce-Dol Catalysis

Compared with fossil energy,biomass has a wide range of sources,renewable,low-carbon and environmental protection.It is a kind of clean and green energy.In recent years,as a new energy conversion technology,biomass catalytic gasification technology has low cost and low energy consumption,which has been valued by researchers and developed rapidly.However,in the research process,it is found that there are some problems in biomass gasification technology,such as high tar content in gasification products will lead to corrosion damage of pipelines,low hydrogen production rate,low mechanical strength of traditional ore catalysts,short service life and low calorific value of gas products.Therefore,developing a new catalyst with good catalytic effect,high mechanical strength,convenient recovery and stable performance has become a new challenge for researchers.In this thesis,the agricultural and forestry waste pine wood is used as the biomass raw material,the rare earth element Ce is used as the metal additive,and the clay ceramic prepared with natural dolomite as the main aggregate in the"one-step"method of powder sintering is used as the catalyst carrier.The new Ce dol clay ceramic catalyst developed by the combination of the two is used in the catalytic gasification experiment of biomass.The catalyst was characterized by scanning electron microscope（SEM）,X-ray diffraction（XRD）and specific surface area test（BET）.The mechanism of catalytic pyrolysis of pine wood was analyzed by thermogravimetric analysis.Using the two-stage fixed bed gasification reactor designed by the research group as the experimental platform,the effects of different additive ratio,different gasification temperature,different steam flow and different catalytic reforming temperature on the gas-phase and liquid-phase products of biomass catalytic gasification process were studied.The Ce dol clay ceramic catalyst was optimized and the optimal working condition was determined.The following results were obtained:（1）The dolomite based clay ceramic prepared with natural dolomite and bentonite as the main aggregate is filled as the active component and carrier of the catalyst,and the rare earth element Ce is loaded on the clay ceramic carrier by impregnation method to prepare a new Ce dol clay ceramic catalyst.According to the test results of scanning electron microscope,X-ray diffraction,specific surface area and other test technologies,the prepared new catalyst has good loading effect,At the same time,it also effectively improves the mechanical strength and prolongs the service life of the catalyst.（2）The pyrolysis of pine wood was catalyzed by Ce dol clay ceramic catalyst.When the heating rate is 15℃/min and the Ce loading is 6%,the weight loss rate of the sample is the highest,and the final weight loss is 44.49%.During pyrolysis,the oxygen-containing functional groups such as carboxyl,hydroxyl and carbonyl on the surface of biomass break and recombine,releasing small molecular gases such as CO₂,H₂O,CO and CH₄and organic compounds such as carboxylic acid and benzene ring.（3）The experiment of catalytic gasification of pine wood with Ce dol clay pottery is carried out.The results show that when the load of CE reaches 6%,the gasification temperature is 850℃,the catalytic reforming temperature is 850℃,and the water vapor flow is 4ml/min,it is the ideal and best working condition.At this time,the volume fraction of H₂reaches the maximum value of 37.37%.From the perspective of liquid phase products,under the conditions of increasing temperature,load and steam flow,the product tar can be further catalytic cracked,and the heavy hydrocarbons,carboxylic acids and phenolic compounds contained in it have decreased to varying degrees,which is consistent with the change law of gas phase products.The addition of rare earth Ce can significantly improve the catalytic activity,improve the efficiency of hydrogen production,and promote the secondary cracking of biomass tar.In this thesis,the Ce dol clay ceramic catalyst prepared by the method of preparing ceramics first and then loading CE shows a good effect of pine catalytic gasification,and obtains an ideal test condition,which is of great practical significance for improving the utilization rate of biomass,improving the mechanical strength of the catalyst,increasing the recovery rate of the catalyst and increasing the service life of the catalyst.It can provide a reference for the application and promotion of biomass catalytic gasification technology.