摘要
针对催化裂化原料日益重质化的趋势,提出了一种后置烧焦管式组合再生工艺。后置烧焦管出口的气固分离装置是实现这种工艺的关键设备之一。为此,设计了一种基于离心与惯性分离原理相结合的新型气固分离器。为了详细研究该分离器,结合流场实验结果,采用数值模拟方法对该分离器内的气相流场进行了数值模拟,数学模型为标准湍流模型。模拟结果给出了分离器内的流场总体特征为:气流以切向速度为主,竖直向上进入分离器的气体绕排气管做旋转运动,先后由排气管上的窄缝排出,部分气体由排气管下方空间返回入口区;拱形分离空间内切向气速随径向位置的增加而减小。排气管上的开缝形式是分离器压降增加的主要因素。将排气管上的两条窄缝改成总面积与排气管内截面积相等的均匀切向窄缝,避免了管内旋流涡核的偏心,分离器压降明显降低。
As the feed stuffs of fluid catalytic cracking （FCC） become increasingly heavier, a new regeneration technology combining post coke-burning riser and conventional turbulent bed regenerator was proposed. One of the key components of this technology is the gas-solids separator located at the outlet of the riser regenerator. A novel gas-solids separator incorporating inertial and centrifugal separation mechanism was designed to satisfy the need of the new technology. In order to study the separator proposed in detail, a numerical simulation method combining the experimental results was used to simulate the flow field in the separator. The mathematical model used is the standard turbulent flow model, and the entire characteristic of the flow field in the separator is as follows. The tangential velocity of the gas is dominative, the gas upflowing into the separator flows around the exhaust pipe and most of it enters in the exhaust pipe through two slots on the pipe wall in turn, and the remainder part of gas returns to the inlet region through the channel below the exhaust pipe, and the tangential velocity in vaulted space of separator decreases with the increase of radius. The simulation results indicate that the way of opening two slots on the exhaust pipe is the main factor increasing the pressure drop of the separator. After changing the way of opening two slots on the exhaust pipe into opening a series of uniformly spreaded tangential slots along the circular wall of the exhaust pipe in the direction of contrary to the gas flow with the total slot opening area equal to the flowing area of the exhaust pipe, the deviation of vortex core from the axis of the exhaust pipe is avoided, and the pressure drop of the separator can be decreased obviously.
出处
《高校化学工程学报》
EI
CAS
CSCD
北大核心
2007年第3期392-397,共6页
Journal of Chemical Engineering of Chinese Universities
关键词
气固分离器
流场
数值模拟
开缝形式
压降
gas-solids separator
flow field
numerical simulation
slot opening form
pressure drop
