重质原油焦化和传统减压渣油焦化的对比研究

重质原油直接焦化工艺路线已成为一些炼油企业首选的加工劣质原油的方案。介绍了重质原油直接焦化装置的特点，对重质原油焦化与传统减压渣油焦化的腐蚀类型、产品分布、加热炉及焦炭塔运行情况、开工过程操作情况等方面进行比较。 减压渣油焦化的腐蚀类型主要包括高温硫腐蚀、低温硫化氢腐蚀，而重质原油焦化的腐蚀类型主要为环烷酸腐蚀；相同循环比下，重质原油焦化的中间组分收率较高，而减压渣油焦化的焦炭、富气产率较高，总液体收率较低；重质原油焦化的加热炉结焦倾向远低于减压渣油焦化的加热炉；重质原油焦化装置焦炭塔内的气相线速略低于减压渣油焦化装置。

A COMPARISON STUDY OF HEAVY CRUDE DELAYED COKING AND VACUUM RESIDUE DELAYED COKING

In some refining enterprises, using delayed coking to process heavy crude directly becomes the first choice of processing inferior crude. The features of heavy crude delayed coking are introduced in this paper, and the delayed coking processes of processing heavy crude and conventional vacuum residue (VR) are compared from the aspects of corrosion type, product distribution, operation of heating furnace and coke drum, as well as startup procedure. It can be seen that in VR delayed coking, high temperature sulfur corrosion and low temperature H2S corrosion are the main corrosion types; for heavy crude delayed coking, naphthenic acid corrosion is the dominant one. Under the same recycle ratio, in heavy crude delayed coking the total liquid yield is higher, especially middle distillate; yet for VR delayed coking, the yields of coke and rich gas are higher, total liquid yield is relatively lower. The coking tendency in heating furnace of heavy crude delayed coking is much lower than that of VR delayed coking, besides, the gas linear velocity in coke drum of the former is also slightly lower than that of the latter.