汽相分流催化精馏塔中苯氯化工艺过程——床层压降和分流比例的计算

Process of Chlorination of Benzene in Catalytic-Distillation Column with Vapor Diffluence——Calculation of Pressure Drop of Beds and Ratio of Vapor Diffluence

针对若直接将苯氯化固体催化剂颗粒堆放在工业催化精馏塔中使用,会引起很大的床层压降使操作无法正常进行的问题,根据床层压降与汽(气)速的平方成正比的原理,提出了将从塔釜上升的大量苯蒸汽由旁路通过而不直接通过催化剂床层以大大降低床层压降的设想,但这样催化剂床层主要起催化反应的作用,精馏分离的作用被大大削弱,导致氯苯选择性下降。因此上行汽体不宜全部分流,存在适宜的分流比。据此设计了一种结构新颖的催化精馏实验装置。在此催化精馏塔中,可实测催化剂床层压降;在不同的催化剂装填方式下,计算了上行汽体不同的侧线分流比例及床层压降降低的比例,当上行汽(气)体分流比分别为58.4%,37.9%和27.8%时,对应的床层压降降低的百分率分别为57.25%,40.68%和32.25%。对工业规模的催化精馏塔的床层压降进行了理论估算。

According to the fact that the direct load of the small particle catalyst in commercial scale catalyticdistillation tower results in remarkable pressure drop which makes operation infeasible, an idea is put forth that part of the benzene vapor rising from the tower bottom can shunt through bypass instead of passing through the catalyst beds because the bed pressure drop is direct ration to the square of flow rate. But, in this way, the catalyst beds were of the mere catalysis and the great decline of separation function is made, which makes chlombenzene selectivity lower. Them was a suitable flow distribution ratio between the bed and the bypass. A kind of catalyticdistillation experiment equipment of the new idea mentioned above was designed. The pressure drop of the beds in the equipment was measured. Different flow distribution ratios between the beds and the bypass and the lower proportion of the bed pressure drop under the different packing modes of catalyst were calculated. When the vapor diffluence proportion was 58.4% ,37.9% and 27.8% ,the corresponding lowered proportion of the bed pressure drop was 57.25 %,40.68 % and 32.25 %, respectively. The value of pressure drop in a commercial scale catalytic-distillation tower was also estimated.