Session: FSI-01-01 Thermal Hydraulic Phenomena with Vessels, Piping and Components

Paper Number: 106127

106127 - Cfd Investigation of Effects of Different Feed Injection Schemes on Reaction Coking in an Industrial Rfcc Riser 

Heavier and poorer crude oils often produce more reaction coke and lower yield of target product such as gasoline and LPG in a commercial FCC riser, and then affect the safety and running period of reactor. Our previous cold-model simulation indicated that a modification from the conventionally upward feed injection scheme to a downward one improves the oil-catalyst mixing. This work aims to investigate improve oil cracking reaction and avoid coking process with an downward feed injection scheme, wherein the feed jets counter-currently impact the catalyst particle flow from riser bottom. A twelve-lump kinetics and vaporization of liquid oil were considered in a multiphase Eulerian model with the energy minimization multi-scale model(EMMS). The extent of fixed coke near riser wall was predicted with our fixed coking model in simulation. Comparison with simulation date of upward feed injection scheme is conducted in terms of the profiles of oil gas component and fixed coke and the yields of gasoline and LPG at riser outlet. The results show that the simulation approach can accurately predict the complex processes of gas-liquid-solid three-phase flow, vaporization and reaction coking. Big discrepancies of multiphase flow and mixing occurs in the feed injection zone. The counter-current feed injection scheme can accelerate the vaporization of liquid oil droplets and speed up the heat and mass transfer compared with the traditional upward scheme; moreover, it can also improve the product yields and obviously reduce the deposition of coke near riser wall, especially in the feed injection zone. A optimal operation condition with the counter-current scheme can greatly improve the conversion of raw oil, increase the yield of target products such as gasoline and LPG, and reduce the amount of coke produced by reaction (19.49%).

 

Key Words：Residue Fluid Catalytic Cracking, Counter-Current Feed Injection, Reaction Coking, Riser reactor, Simulation

Presenting Author: 盛 陈 中国特种设备检验研究院国家市场监管炼化装备风险防控技术创新中心

Presenting Author Biography: Dr. Chen is from Beijing in China, working in China Special Equipment Inspection and Research Institute. He is a senior engineer, studying on the risk assessment and the multiphase flow simulation analysis for pressure vessels and pipes. He had been working on optimization of the structure of catalytic cracking reactors since his PhD, and some technologies such as atomized feed oil had been used to guide industrial applications.

Authors:

Sheng Chen Technology Innovation Center of Risk Prevention and Control of Refining and Chemical Equipment for State Market Regulation, China Special Equipment Inspection and Research Institute
Zihan Yan State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing, Beijing
Ming Chen Technology Innovation Center of Risk Prevention and Control of Refining and Chemical Equipment for State Market Regulation, China Special Equipment Inspection and Research Institute
Mengxi Liu State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing
Juanbo Liu State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing
Guoshan Xie State Key Laboratory of Heavy Oil Processing, College of Chemical Engineering and Environment, China University of Petroleum-Beijing