摘要
利用数值模拟技术,对比考察了旋风分离器采用轴对称双进口和单边切向进口时升气管外壁附近及环形空间的静压和切向速度分布,分析比较这两种进口形式下升气管外切向剪切力和径向压力梯度力对升气管外壁结焦物沉积与积累的影响。结果表明,双入口分离器升气管近壁环向顺、逆压梯度区范围均小于单进口分离器,切向速度沿环向变化不明显,近壁低速易沉积区范围小,且不容易出现油气及催化剂的回流和滞留区,能有效抑制结焦物的沉积;双进口分离器升气管近壁区的平均剪切力比单进口分离器大30%以上,而平均径向压力梯度力比单进口分离器约小17%,能一定程度上削减结焦层厚度,抑制结焦物积累的能力强于单进口。轴对称双进口旋风分离器升气管外壁结焦的倾向将明显小于单切向进口的旋风分离器。
The tangential velocity and static pressure distribution at the outer wall of vortex finder through a single and a double inlet cyclone were simulated using RSM model.It is shown that the adverse and favorable pressure gradient zone along the outer wall of vortex finder of the double-tangential-inlet cyclone separator is much smaller than that in single-tangential-inlet cyclone separator.The tangential gas velocity around the vortex finder wall has no significant fluctuation and the easy deposit area for oil drip and catalyst is relatively small.There is no stagnant flow area,and the back flow zone near vortex finder wall is not prone to yield.Consequently the probability of coke accumulation on the outer wall of vortex finder of a double-tangential-inlet cyclone is less than that in a single-tangential-inlet cyclone.On the other hand,in double-tangential-inlet separator,the average shearing strength to the coke deposited on the outer wall of vortex finder is large and the average radial pressure grads force is small,which suggests less coking and thinner coke layer on the outer wall of vortex finder.
出处
《化工学报》
EI
CAS
CSCD
北大核心
2010年第9期2379-2385,共7页
CIESC Journal
基金
中石化重油催化沉降器抑制结焦项目(305013)
关键词
旋风分离器
升气管外壁
结焦
双入口
径向压力梯度
cyclone separator
outer wall of vortex finder
coke
double-inlet
radial pressure grads
