Nitric acid reduction method used in methyl nitrite preparation process

Abstract

The invention discloses a nitric acid reduction method in the preparation process of methyl nitrite. The circulating tail gas and the bottom liquid of the esterification tower from the nitric oxide circulating compressor are respectively heated and then sent to the nitric acid reduction tower. The reaction is carried out from top to bottom. The vapor phase at the outlet of the reduction tower bottom is cooled and then enters the discharge flash tank at the bottom of the nitric acid reduction tower. The liquid phase is pumped and then sent to the top of the stripping tower. The carbon monoxide gas is in countercurrent contact, the methyl nitrite gas and nitrogen monoxide gas in the liquid phase are stripped, the vapor phase at the top of the stripping tower and the cooled vapor phase at the top of the reduction tower enter the flash tank together, and are separated by flash evaporation Finally, the gas phase returns to the cycle gas compressor, and the liquid phase is vaporized before tail gas treatment.

Description

Technical field [0001] The invention relates to a production process of dimethyl oxalate. The dimethyl oxalate can be used in various organic synthesis, and is especially suitable for the preparation of dimethyl oxalate in the synthesis of ethylene glycol. Background technique [0002] The nitric acid reduction method in the preparation process of methyl nitrite described in the present invention is suitable for the preparation process of dimethyl oxalate. Dimethyl oxalate is an intermediate widely used in organic synthesis and can also be prepared by hydrogenation. Take ethylene glycol. At present, the industrial production of large-scale ethylene glycol at home and abroad adopts the process route of direct hydration of ethylene oxide, which has a long process flow, many equipment and high energy consumption. With the vigorous development of coal-based ethylene glycol technology, the synthesis gas to ethylene glycol technology using dimethyl oxalate as an intermediate product w...

AI Technical Summary

Problems solved by technology

The methyl nitrite gas used in the synthesis of dimethyl oxalate is produced by the reaction of methanol, nitric oxide and oxygen. In the moisture environment generated by the reaction, nitric oxide will be over-oxidized by oxygen to generate nitric acid. This part of nitric acid gas It will accumulate in the circulating gas and affect the operation of the equipment. The original process is to discharge the tail gas regularly, which will not only cause environmental pollution, but also cause waste of raw materials.

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