METHOD FOR RECYCLING METHANOL IN THE PROCESS OF PREPARING DIMETHYL OXALATE FROM SYNTHESIS GAS

摘要

A method for recycling methanol in a process of preparing dimethyl oxalate from synthesis gas is provided according to the present disclosure, comprising the steps of: i) a crude methanol stream containing methyl nitrite, methyl formate, and dimethyl carbonate is fed into a firs1 separation column, and methyl nitrite is obtained at a top thereof and a crude methanol stream containing methyl formate and dimethyl carbonate is obtained at a bottom thereof; ii) the crude methanol stream containing methyl formate and dimethyl carbonate is fed into a second separation column, and methyl formate is obtained at a top thereof and a crude methanol stream containing dimethyl carbonate is obtained at a bottom thereof; and iii) the crude methanol stream containing dimethyl carbonate is fed into a dimethyl carbonate-methanol separation unit, and dimethyl carbonate and methanol stream to be recycled are obtained after separation. According to the method of the present disclosure, methyl formate accumulated in the system can be reduced, and thus the corrosion of the pipelines and the equipment can be alleviated. In addition, the purity of methanol can be improved, and thus the circulation volume thereof can be reduced, thereby the power consumption can be lowered. The present method has evident economical benefit. Figure 1 is the representative figure.