CN-121797226-B - Method and device for producing oxamide

CN121797226BCN 121797226 BCN121797226 BCN 121797226BCN-121797226-B

Abstract

The application provides a device and a method for producing oxamide, wherein the device comprises a reaction device, a gas-liquid separation device, a solid-liquid separation device, a drying device, a crude rectifying tower, a methanol purifying system, a washing condensing tower and an alcohol ester mixer. The application uses the relatively high heat energy generated by ammonolysis reaction for drying the oxamide powder, uses the relatively low heat energy for reboiling the crude rectifying tower, introduces the second ammonia gas phase generated by the drying device into the crude rectifying tower to fully utilize the heat energy, and refines the crude methanol obtained by the crude rectifying tower in an adsorption or membrane separation mode, so that the ammonia content in the refined methanol can be reduced to 1ppm. The technical scheme provided by the application fully utilizes the ammonolysis reaction heat and the gas waste heat of the drying device, and the methanol refining adopts an adsorption or membrane separation process, so that the production cost of the oxamide can be obviously reduced. Furthermore, the scheme provided by the application can produce high-purity methanol for take-out or return to the dimethyl oxalate synthesis section for use.

Inventors

JIA JINJIE
YU JUN
LI QUANWEI
YUAN LIANGZHENG
XU XIN
LIU XIAOLEI
CHEN QIAN
ZHANG BING
QIAN JUN
GAO JIAN

Assignees

东华工程科技股份有限公司

Dates

Publication Date: 20260508
Application Date: 20260309

Claims (10)

1. An apparatus for producing oxamide comprising: the reaction device is used for ammonolysis reaction of the alcohol ammonia liquid phase and the alcohol ester liquid phase; the material inlet is communicated with a material outlet of the reaction device; The material inlet is communicated with the liquid phase material outlet of the gas-liquid separation device; the material inlet is communicated with a solid-phase material outlet of the solid-liquid separation device; the liquid-phase material inlet is communicated with a liquid-phase material outlet of the solid-liquid separation device, and the gas-phase material inlet of the coarse rectification tower is communicated with a gas-phase material outlet of the drying device; The liquid-phase material inlet is communicated with the liquid-phase material outlet of the crude rectifying tower; The gas-phase material inlet is respectively communicated with a gas-phase material outlet of the crude rectifying tower, a gas-phase material outlet of the gas-liquid separation device, a liquid-phase material outlet of the solid-liquid separation device and a gas-phase material outlet of the methanol purification system; The liquid-phase material inlet is respectively communicated with the liquid-phase material outlet of the washing condensing tower, the material outlet of the dimethyl oxalate supply device, the material outlet of the methanol supply device and the liquid-phase material outlet of the solid-liquid separation device, and the liquid-phase material outlet of the alcohol-ester mixer is respectively communicated with the liquid-phase material inlet of the washing condensing tower and the liquid-phase material inlet of the reaction device.
2. The apparatus of claim 1, wherein the liquid phase feed outlet of the solid liquid separation device is in communication with the feed inlet of the reaction device.
3. The apparatus of claim 1, wherein the reaction apparatus comprises: reactor for ammonolysis reaction of alcohol ammonia liquid phase and alcohol ester liquid phase, and And the material outlet of the purifier is communicated with the material inlet of the gas-liquid separation device.
4. The apparatus of claim 3, wherein the purifier comprises a first stage purifier in communication with the material outlet of the reactor and a second stage purifier in communication with the material outlet of the first stage purifier; the relatively high-level waste heat of the first section purifier provides heat energy for the drying device through a first heat conveying device; The relatively low-level waste heat of the second section purifier provides heat energy for the crude rectifying tower through a second heat conveying device.
5. The apparatus according to claim 4, wherein the crude rectifying column is provided with a condenser at the top and a reboiler at the bottom.
6. The apparatus of claim 5, wherein the relatively low waste heat of the second stage purifier provides thermal energy to the reboiler of the crude rectifier via a second heat transfer device.
7. The apparatus of any one of claims 1-6, wherein the methanol purification system is an adsorption device or a membrane separation device.
8. The apparatus of claim 1, further comprising a final scrub column in communication with the vapor phase material outlet of the scrub-condensing column.
9. A method for producing oxamide, characterized in that the production is carried out by using the device according to any one of claims 1 to 8, comprising the following steps: mixing a first alcohol ester liquid phase mixture generated by a washing condensing tower, a fourth alcohol ammonia liquid phase mixture generated by a solid-liquid separation device and dimethyl oxalate in an alcohol ester mixer to obtain an alcohol ester liquid phase mixture, wherein the alcohol ester liquid phase mixture is divided into a third alcohol ester liquid phase mixture and a second alcohol ester liquid phase mixture; Mixing the first alcohol ammonia liquid phase mixture generated by the solid-liquid separation device with liquid ammonia to obtain a third alcohol ammonia liquid phase mixture; Mixing a third alcohol ester liquid phase mixture with a third alcohol ammonia liquid phase mixture, and then carrying out ammonolysis reaction to obtain first slurry, wherein the first slurry is subjected to gas-liquid separation to obtain a second slurry and a first alcohol ammonia gas phase mixture; The second slurry is subjected to solid-liquid separation to obtain a third slurry and an alcohol ammonia liquid phase mixture, the third slurry is dried to obtain an oxamide solid product and a second alcohol ammonia liquid phase mixture, and the alcohol ammonia liquid phase mixture is divided into a first alcohol ammonia liquid phase mixture, a second alcohol ammonia liquid phase mixture, a fourth alcohol ammonia liquid phase mixture and a fifth alcohol ammonia liquid phase mixture; Treating the second ammonia liquid phase mixture and the second ammonia gas phase mixture in a crude rectifying tower to obtain a third ammonia gas phase mixture and crude methanol, and purifying the crude methanol; the fifth alcohol ammonia liquid phase mixture, the third alcohol ammonia gas phase mixture, the first alcohol ammonia gas phase mixture, the regenerated gas, the sealing gas and the safety valve exhaust gas are washed in a washing condensing tower to obtain a first alcohol ester liquid phase and process tail gas.
10. The method of claim 9, wherein the pressure in the scrub condensation column is a micro positive pressure relative to the excess ammonia of dimethyl oxalate.

Description

Method and device for producing oxamide Technical Field The application relates to the technical field of novel fertilizer production, in particular to a method and a device for producing oxamide. Background The oxamide is a high-efficiency slow-release nitrogen fertilizer, has the advantages of no toxicity, small solubility in water, lasting fertilizer efficiency and the like, and can effectively promote plant growth and improve the yield and quality of crops after reasonable use. The preparation of oxamide by ammonolysis reaction of dimethyl oxalate and liquid ammonia is a production method commonly used in industry at present, and the route has the advantages of mild reaction conditions, easily obtained raw materials and the like. In the process of preparing the oxamide by utilizing the ammonolysis reaction of the dimethyl oxalate and the liquid ammonia, the byproduct methanol of the ammonolysis reaction is required to be extracted from an oxamide production device in order to ensure the device to stably operate. If the extracted methanol is sold, the extracted methanol needs to meet the requirement specification specified in industrial methanol (GB/T338-2011). In a factory for producing dimethyl oxalate and co-producing oxamide, methanol can be returned to a dimethyl oxalate production section, and at the moment, the extracted methanol needs to meet the specification required by the dimethyl oxalate production section, for example, the lower the dimethyl oxalate and the ammonia content are, the better the service life of a dimethyl oxalate synthesis catalyst is prolonged. In the prior art, the methanol is separated from ammonia or dimethyl oxalate by adopting a rectification method, but a large amount of steam is consumed in rectification, and the steam consumed per ton of methanol is more than 0.3t. Further, when the content of dimethyl oxalate or ammonia in methanol is reduced to 1ppm, higher reflux ratio is required for rectification, and thus higher steam consumption is generated. Disclosure of Invention In view of the above, the present application provides a method and apparatus for producing oxamide, and the method and apparatus provided by the present application are used for producing oxamide, and can fully utilize ammonolysis reaction heat and gas waste heat of a drying apparatus, so as to significantly reduce oxamide production cost. The application provides a device for producing oxamide, which comprises: the reaction device is used for ammonolysis reaction of the alcohol ammonia liquid phase and the alcohol ester liquid phase; the material inlet is communicated with a material outlet of the reaction device; The material inlet is communicated with the liquid phase material outlet of the gas-liquid separation device; the material inlet is communicated with a solid-phase material outlet of the solid-liquid separation device; the liquid-phase material inlet is communicated with a liquid-phase material outlet of the solid-liquid separation device, and the gas-phase material inlet of the coarse rectification tower is communicated with a gas-phase material outlet of the drying device; The liquid-phase material inlet is communicated with the liquid-phase material outlet of the crude rectifying tower; The gas-phase material inlet is respectively communicated with a gas-phase material outlet of the crude rectifying tower, a gas-phase material outlet of the gas-liquid separation device, a liquid-phase material outlet of the solid-liquid separation device and a gas-phase material outlet of the methanol purification system; The liquid-phase material inlet is respectively communicated with the liquid-phase material outlet of the washing condensing tower, the material outlet of the dimethyl oxalate supply device, the material outlet of the methanol supply device and the liquid-phase material outlet of the solid-liquid separation device, and the liquid-phase material outlet of the alcohol-ester mixer is respectively communicated with the liquid-phase material inlet of the washing condensing tower and the liquid-phase material inlet of the reaction device. In some specific implementations, the liquid phase material outlet of the solid-liquid separation device is in communication with the material inlet of the reaction device. In some specific implementations, the reaction device includes: reactor for ammonolysis reaction of alcohol ammonia liquid phase and alcohol ester liquid phase, and And the material outlet of the purifier is communicated with the material inlet of the gas-liquid separation device. In some specific implementations, the purifier includes a first stage purifier in communication with the material outlet of the reactor and a second stage purifier in communication with the material outlet of the first stage purifier; the relatively high-level waste heat of the first section purifier provides heat energy for the drying device through a first heat conveying device; The relatively low-level was