硅铬复合氧化物抗结焦涂层的制备及其性能

Preparation and Performance of Composite Silica and Chromic Oxide Coating for Anti-Coking

采用化学气相沉积法在裂解小试装置的裂解炉管内制备了硅铬复合氧化物抗结焦涂层。通过裂解结焦实验、元素分析和SEM方法对硅铬复合氧化物涂层在裂解炉管内的分布规律、抑制结焦能力和抗高温冲击能力以及涂层对烯烃收率的影响进行了研究。在裂解炉管内沉积硅铬复合氧化物涂层时,炉管入口沉积的涂层中含有较多的氧化铬,中间段的涂层主要为硅铬复合氧化物,而出口的涂层含氧化硅较多。所制备的涂层前期结焦抑制率可达90%,在第14次评价周期后,结焦抑制率仍保持在80%以上。硅铬复合氧化物涂层能耐受1 000℃的热冲击,具有较好的牢固度,并对乙烯、丙烯和丁二烯收率的影响不明显。

Composite silica and chromic oxide coating for anti-coking was prepared on the internal surface of a cracking furnace tube through chemical vapor deposition in the laboratory scale steam cracker for ethylene production.The distribution of silica and chromic oxide on the tube,the anticoking performance,the high temperature resistance and the influence of the coating on the yield of olefins were studied by means of EDS,SEM and steam cracking experiments.In the inlet,middle section and exit of the tube,more chromic oxide,composite silica and chromic oxide,and more silica were deposited,respectively.The coking inhibition rate reached 90％ at the earlier running stage and was kept above 80％ after the fourteen circles of steam cracking of naphtha.The coating kept good performance even after it was treated with thermal shock at 1 000 ℃.No obvious influence of the coating on the yields of olefin products was observed.