6000吨年苯酐装置的工艺设计

6000吨/年苯酐装置的工艺设计

摘要

苯酐是重要的有机化工原料之一，用于生产增塑剂、醇酸树脂、不饱和聚酯树脂、染料及颜料、医药及农药等。目前，全球苯酐生产所采用的工艺路线有萘流化床氧化和萘/邻二甲苯固定床氧化，其中邻二甲苯固定床氧化技术约占世界总生产能力的90%以上。本设计采用邻二甲苯氧化连续式生产邻苯二甲酸酐，该法工艺比较成熟，资料较多，故采用该工艺。

本设计根据年产6000吨/年的生产需求对苯酐装置进行了设计。设计中采用以五氧化二钒为主的钒系催化剂进行邻二甲苯的气相氧化，反应器采用列管式固定床反应器。将过滤后的无尘气经压缩、预热至160℃，与被气化的邻二甲苯蒸气混合后进入反应器，在400-460℃进行催化氧化反应，反应进料空速3200h-1，空气中邻二甲苯浓度40g/m2（标准），反应热由管外循环的熔盐带出。反应产物进入熔盐冷却器，被冷却的反应气经进一步冷却，进入粗酐贮槽，回收粗苯酐。同时尾气经水洗塔回收顺丁烯二酸酐后放空。粗苯酐经减压蒸馏，由初馏塔塔顶分离出低沸点的顺丁烯二酸酐，甲基顺丁烯二酸酐及苯甲酸等；塔底物料经精馏塔真空精馏，在塔底蒸出苯酞等重组分，再由塔顶得到精制苯酐产品，最后结片包装。

本设计确定生产6000吨邻苯二甲酸酐的合理生产工艺；完成年产6000吨苯酐生产的全部工艺计算（物料衡算，热量衡算），根据工艺计算确定生产设备的工艺尺寸；绘制工艺流程简图、带控制点的工艺流程图和设备图。

关键词苯酐；邻二甲苯；邻苯二甲酸酐；工艺设计

Design of phthalic anhydride of yearly produces

6000 tons

Abstract

Phthalic anhydride is one of important organic Chemical industry material for producing plasticizer、alkyd resin、unsaturated polyester resin、dyestuff and pigment、medicine and pesticide. Currently, the process routes of phthalic anhydride produceing are fluidized bed oxidation of naphthalene and fixed bed oxidation of o-xylene/naphthalene all over the world. And the technology of fixed bed oxidation of o-xylene is about 90% of the world's total production capacity. This design uses the method of o-xylene oxidation to produce Phthalic anhydride continuously. The technology is mature and more information,so it is used.

According to the production requirements of annual output of 6000 tons, phthalic anhydride plant is designed. The design is gas phase oxidation of o-xylene by vanadium catalyst, which is mainly about vanadium pentoxide. The reactor used is tubular fixed-bed reactor. Detailed design process: After fliteration, no the dust gas is compressed、preheated by 160℃, and sent into the reactor mixing with o-xylene steam which has been gasified. Catalyze oxide reaction is continued in 400-460℃. Airspeed of response feed is 3200h-1, the concentration of o-xylene in air is 40g/m2 (stp), heat of reaction is taken away by molten salt, which recycle outside the pipe. Product of reaction sent into salt cooler, cooled reaction gas sent into crude anhydride tank after further cooling. At the same time, exhaust is recovered by Water Scrubber to get maleic anhydride, then shorting. By vacuum distillation, Maleic anhydride，Methyl

maleic anhydride and Benzoic acid is separated from crude anhydride by the tower of the first distillation, with low boiling point. Bottom of the column material is made vacuum distillation by the second distillation column. Phthalide and other fractions are steamed at the bottom of tower, then get refined phthalic anhydride product from the tower . At last, sheeting and package.

This design determines a reasonable production process of 6000 tons Phthalic anhydride; Completes process calculation(mass balance, heat balance) of producing 6000 tons o-xylene anhydride; According to process calculation, calculate the size of the production process equipment, drawing process diagrams、process diagrams with control points and equipment chart

Keywords：Phthalic anhydride；O-xylene；Phthalic anhydride；Process Design