Study On Industial Application Of Anti-coking Coating Of Ethylene Cracking Furnace

Ethylene is one of the basic organic chemical products in the petrochemical industry.The steam cracking,by which about 95%of the world’s ethylene production are produced.In the steam cracking process,the internal coking of the tube section of the cracking furnace and the transfer line exchanger is the main factor affecting the operation cycle of the cracking furnace.It is understood that the domestic ethylene cracking furnace operating cycle of about 60 days,after each operation cycle to be 3 to 4 days to stop the fire online.Cracking furnace on-line cleaning on the one hand consume a lot of fuel,steam,electricity,compressed air,significantly reducing the effective production time of cracking furnace,on the other cracking furnace cleaning process to speed up the equipment damage.Therefore,the study of cracking reaction coking mechanism and the development of new anti-coking coating or material has great practical significance on the petrochemical industry.In this paper,the in-situ coating technology is based on the principle of catalytic coking,When the furnace tube is treated under specific atmosphere conditions,the Mn and Cr elements in the furnace tube are slowly oxidized into a chromium manganese spinel protective film on the surface of the furnace tube,which is easy to cause Ni,Fe and other elements in the coke.The Ni and Fe elements in the furnace tube material are shielded,and the carburizing performance of the furnace tube is effectively improved,thereby suppressing the entire coking of the cracking reaction.Process and catalyze coking reactions.The oxide film has the characteristics of dense intergranular grain,small grain size,good coking resistance and low stress to the substrate.The oxidation treatment is not limited by the shape of the sample with relatively low cost,so this is a relatively promising furnace Pipe alloy surface treatment and anti-coking method.Anti-coking technology with in-situ coating was applied to an SRT-IV-HC 60KTA ethylene cracking furnace in Yansan Petrochemical Company’s ethylene plant for industrial application test research.The results show that under the premise with no obvious change of the product’s yield after the application of the in-situ coating technology,the temperature rise of the tube metal temperature of the radiation section is reduced obviously,and the average operating period of the cracking furnace is increased from 52 days to 158 days and the average running cycle is extended by 2 times under the premise of no significant change in the yield of cracking furnace,After six cycles of operation,the anti-coking effect of in-situ coating was not weakened.