Abstract:

The jet flow induces an important mesoscale flow structure in the riser reactor, which has an important impact on the product yield, selectivity and coking on the inner wall of the riser. Research on gas jet hydrodynamics in a feedstock injection zone of a riser and the intensification strategy was reviewed in this paper. The secondary flow is the main reason for the unmatching concentration of feedstock and catalyst in a feedstock injection zone with traditional and upward jet injection scheme. Based on Kutta-Joukowski theorem, the formation mechanism of the secondary flow, the trajectories of the main flow and secondary flow, as well as the intensification strategy of feedstock-catalyst countercurrent contact were introduced and analyzed theoretically. Focusing on RFCC and pyridine synthesis processes, work associated with laboratory findings and commercialized units test were introduced in terms of intensification methods such as oil-catalyst countercurrent contact and dual layer nozzles. The results show that product yields increase and the coking inside the reactor is significantly relieved after the strategy was used.

Key words: riser, multiphase flow, mesoscale, jet, process intensification

摘要：

射流促使提升管反应器中产生了重要的介尺度流动结构，对产品的收率、选择性以及提升管内壁的结焦都有重要的影响。对近年来提升管进料区内射流流动行为及调控的研究进行了回顾。二次流是造成传统进料区原料-催化剂浓度不匹配的主要原因。基于Kutta-Joukowski升力定律，从理论上介绍了二次流形成的机理以及主流、二次流轨迹的预测模型，给出了油剂逆流接触这一强化手段。针对常规催化裂化、吡啶碱合成等工艺，分别介绍了油剂逆流接触、双层喷嘴等不同的进料区流场强化方法、实验室研究结果和工业应用结果。结果显示，采用进料区强化方法后可以提高目标产品的收率并显著缓解反应器内部的结焦现象。

关键词: 提升管, 多相流, 介尺度, 射流, 过程强化