Reactivity And Regeneration Of Catalysts For Catalytic Cracking Of Light Hydrocarbon

It is well known that ethylene and propylene which are the essential organic chemicals play a decisive role in the national petrochemical industry. Their technology level of development has become a measure standard of the country development level. With the development of the world economy, there is a huge market gap of the production. Used the traditional naphtha steam cracking to producte ethylene and propylene has been unable to meet market demand. According to the reports, the catalytic cracking of light hydrocarbon shows lots of strongpoints during the process of preparing ethylene and propylene compared with the steam cracking. Some investigations find that the temperature of catalytic cracking reaction can be descended about 100℃. It is also found the consumed energy of the fittings can be decreased. While we may control the output ratio of ethylene and propylene according to the actual situation. So the scientists try their best to carry on the new light hydrocabon catalytic cracking catalyst in recent years.Catalytic performance of catalysts (H0108 and 1-P-H0108) for catalytic cracking of light hydrocarbon was investigated in a fixed-bed plug-flow reactor under different reaction conditions. It is found that the yield of ethylene and propylene is enhanced and the formation of coke is restrained with the existance of water during the process of the light hydrocarbon catalytic cracking, making the structure of catalysts less stable. TG/DTG results show that there are two types of coke on the catalyst surface and the deactivated catalysts can be regenerated by eliminating the coke at 750℃, coking being the main reason of deactivation in the condition without water during the process of the light hydrocarbon catalytic cracking. The activity of catalysts which have been deactivated in the condition with water can be partly recovered by eliminating coke. NH3-TPD results show that the reason of deactivation in this case is mainly due to the irreversible structural deactivation of catalysts except for coking.In this paper, the coke burning behavior as well as the burning kinetics have been studied by thermgarvimetry(TG). There are two types of carbon found on the catalysts which have been deactivated in the condition without water during the process of the light hydrocarbon catalytic cracking and the kinetic behavior for each type of carbon is discussed individually. There is only one type of carbon found on the catalysts which have been deactivated in the condition with water during the process of the light hydrocarbon catalytic cracking and the kinetic behavior for this carbon is also discussed. The results of the fitting at the dynamics of various types coke combustion activation energy of the relative size are further validated by the element analysis results (EA)of the catalyst surface coking.