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

在相應的工況下在塔內進行反應蒸餾，塔頂產出正丁醇回酯化反應塔循環使用，塔底產出順酐和二酯去精品精餾塔進行順酐精制。具有吸收快、吸收收率高、不腐蝕設備、無三廢、、操作可靠特點。

Under corresponding working conditions, reactive distillation is carried out in the tower, n-butanol produced at the top of the tower is recycled to the esterification reaction tower, and 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 corrosion of equipment, no three wastes, energy saving and reliable operation.

正丁醇在室溫無催化劑條件下，與含有順酐反應生成氣反應生成單酯（ＭＢＭ），再將單酯加熱反應，生成正丁醇和順酐的工藝路線回收順酐的新工藝，它由酯化反應吸收塔１，正丁醇予處理塔２和冷凝器５，冷卻器６，及精品精餾塔４和冷卻器８所構成，其特征在于，設置一個熱分解反應精餾塔３及塔頂冷凝器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 and reacted to produce n-butanol and maleic anhydride. It is a new process for recovering maleic anhydride. It is composed of esterification reaction absorber 1, n-butanol pretreatment tower 2, condenser 5, cooler 6, fine distillation tower 4 and cooler 8, The utility model is characterized in that a thermal decomposition reactive distillation column 3 and a tower top condenser 7 are arranged

該塔以酯化反應吸收塔塔底產出的單酯和一定量的二酯為原料，在進料溫度為５０℃－１２０℃，塔頂真空度為３００－７５０ｍｍＨｇ，回流比為１－３的工況下實行熱分解反應精餾，塔頂產出純正丁醇經冷凝器７送回酯化反應吸收塔１循環使用，塔底產出順酐與二酯送精品精餾塔４進行順酐精制。

The tower uses the monoester and a certain amount of diester produced at the bottom of the esterification reaction absorption tower 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, the thermal decomposition reaction distillation is carried out. The pure butanol produced at the top of the tower is sent back to the esterification reaction absorption tower 1 for recycling through condenser 7, Maleic anhydride and diester produced at the bottom of the tower are sent to high-quality distillation tower 4 for maleic anhydride refining.