【作者】 范怡平； 时铭显； 叶盛； 卢春喜； 孙国刚；

【Author】 FANYi-ping, SHI Ming-xian, YE Sheng, LU Chun-xi, SUN Guo-gang (Dept.Chemical Engineering, University of Petroleum, Beijing 102200, China)

【机构】 石油大学化工学院；

【摘要】 采用现代多相流的测试技术,根据实际工业的操作条件,用催化裂化催化剂及空气,在大型冷模实验装置上对催化裂化提升管进料混合段内射流相流体的扩散和流动行为进行了系统测试。结果表明,当喷嘴射流注入到提升管中以后,将会产生二次流动,二次流先发展扩大,随后又与主流逐渐汇合。研究表明,在提升管进料段内结焦现象产生的真正原因是由于二次流的扩大导致颗粒相返混加剧,而并非目前普遍认为的“油雾喷射到对侧管壁而形成的”。更多还原

【Abstract】 Fluid catalytic cracking (FCC) process is one of the most important heavy oil upgrading techniques in the petroleum refining industry, and the riser reactor is the crucial part in a FCC unit. Experiments were conducted in a big cold riser model made of plexiglass whose cross-section is 0.186 m in ID and height is 14m. The operating conditions were decided according to the practical industry. The solid particles were of a type of FCC cracking catalyst while the gas entering the riser via the nozzles and via the pre-lift zone is air.By employing many modern measuring techniques, the diffusion and flow characteristics of the jets were investigated. The experimental results show that when the nozzle jets are injected into, a secondary flow of the jet fluid comes forth in the vicinity of the riser wall due to vortices regime. This secondary flow expands at first and then merges in the main stream. This paper also indicated that the uppermost reason of charring might be due to the particles performing "analogue of flowing round a blunt body" and extension of jet secondary flow, but not the prevalent viewpoint of "feedstock jet impinging on the opposite riser wall of the atomizing nozzle".更多还原