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.

在相應(yīng)的工況下在塔內(nèi)進(jìn)行反應(yīng)蒸餾，塔頂產(chǎn)出正丁醇回酯化反應(yīng)塔循環(huán)使用，塔底產(chǎn)出順酐和二酯去精品精餾塔進(jìn)行順酐精制。具有吸收快、吸收收率高、不腐蝕設(shè)備、無(wú)三廢、、操作可靠特點(diǎn)。

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.

正丁醇在室溫?zé)o催化劑條件下，與含有順酐反應(yīng)生成氣反應(yīng)生成單酯（ＭＢＭ），再將單酯加熱反應(yīng)，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(yīng)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(gòu)成，其特征在于，設(shè)置一個(gè)熱分解反應(yīng)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 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.

該塔以酯化反應(yīng)吸收塔塔底產(chǎn)出的單酯和一定量的二酯為原料，在進(jìn)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(shí)行熱分解反應(yīng)精餾，塔頂產(chǎn)出純正丁醇經(jīng)冷凝器７送回酯化反應(yīng)吸收塔１循環(huán)使用，塔底產(chǎn)出順酐與二酯送精品精餾塔４進(jìn)行順酐精制。

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.