The invention relates to a process method for recovering maleic anhydride. In this method, n-butanol is esterified with the gas containing maleic anhydride to produce monoester, and then the monoester is decomposed into n-butanol and maleic anhydride. The process is characterized by a thermal decomposition reactive distillation column, which takes monoester and certain content of diester produced by esterification as raw materials.

在相应的工况下在塔内进行反应蒸馏，塔顶产出正丁醇回酯化反应塔循环使用，塔底产出顺酐和二酯去精品精馏塔进行顺酐精制。具有吸收快、吸收收率高、不腐蚀设备、无三废、、操作可靠特点。

Under the corresponding conditions, the reaction distillation is carried out in the tower, the n-butanol produced at the top of the tower is recycled to the esterification reaction tower, and the maleic anhydride and diester produced at the bottom of the tower are sent to the fine distillation tower for maleic anhydride refining. It has the characteristics of fast absorption, high absorption yield, no equipment corrosion, no three wastes, energy saving and reliable operation.

正丁醇在室温无催化剂条件下，与含有顺酐反应生成气反应生成单酯（ＭＢＭ），再将单酯加热反应，生成正丁醇和顺酐的工艺路线回收顺酐的新工艺，它由酯化反应吸收塔１，正丁醇予处理塔２和冷凝器５，冷却器６，及精品精馏塔４和冷却器８所构成，其特征在于，设置一个热分解反应精馏塔３及塔顶冷凝器７。

Under the condition of no catalyst at room temperature, n-butanol reacts with the gas containing maleic anhydride to produce monoester (MBM), and then the monoester is heated to produce n-butanol and maleic anhydride. A new process for recovery of maleic anhydride consists of esterification reaction absorption tower 1, n-butanol pretreatment tower 2, condenser 5, cooler 6, fine distillation tower 4 and cooler 8 A thermal decomposition reactive distillation column 3 and an overhead condenser 7 are arranged.

该塔以酯化反应吸收塔塔底产出的单酯和一定量的二酯为原料，在进料温度为５０℃－１２０℃，塔顶真空度为３００－７５０ｍｍＨｇ，回流比为１－３的工况下实行热分解反应精馏，塔顶产出纯正丁醇经冷凝器７送回酯化反应吸收塔１循环使用，塔底产出顺酐与二酯送精品精馏塔４进行顺酐精制。

In this tower, monoester and a certain amount of diester produced at the bottom of esterification reaction absorption tower are used as raw materials. Under the working conditions of feed temperature of 50 ℃ - 120 ℃, vacuum degree at the top of the tower of 300-750mmhg and reflux ratio of 1-3, thermal decomposition reactive distillation is carried out. Pure butanol produced at the top of the tower is sent back to esterification reaction absorption tower 1 for recycling through condenser 7, and maleic anhydride is produced at the bottom of the tower It is sent to fine distillation column 4 for maleic anhydride refining with diester.