A device and method for energy saving and consumption reduction of dimethyl carbonate plant

Abstract

The invention relates to a device and method for energy saving and consumption reduction of a dimethyl carbonate device. The method comprises the following steps that (a) a mixed material of propylene carbonate, methanol and methanol base catalysts passes through a heat exchanger and then enters a reaction rectifying tower for primary reaction and fractionation; a generated azeotrope of dimethyl carbonate and the methanol enters a pressurization rectifying tower after being condensed by a tower top condenser; (b) after the separation by the pressurization rectifying tower, light ingredients enter a methanol rectifying tower to be rectified; (c) an azeotropic composition at the tower top of the methanol rectifying tower is subjected to temperature rise and pressurization through a rectifying heat pump, and is then used as a heat source of a reboiler of the methanol rectifying tower; the azeotrope discharged from the reboiler respectively enters a feeding preheater and a condenser to be cooled through the reaction rectifying tower. The device and method provided by the invention have the beneficial effects that the energy consumption is reduced by 20.2 percent; the distribution of gas phase materials in the tower is more reasonable; the mass transfer separation efficiency of the rectifying tower is improved; in addition, the continuous and regular collection of liquid samples is realized; the product monitoring frequency is greatly improved; the device can be favorably regulated in time.

Description

technical field [0001] The invention relates to the field of dimethyl carbonate production, in particular to a device and method for saving energy and reducing consumption of a dimethyl carbonate plant. Background technique [0002] The rectifying separation purpose of dimethyl carbonate and methanol is to remove the excess methanol added in the reaction process to obtain high-purity dimethyl carbonate product. The rectification separation unit is an important component of the dimethyl carbonate production unit, and its energy consumption is also one of the important factors affecting the production cost of dimethyl carbonate. Therefore, reducing the energy consumption of the rectification unit has also become a key factor in controlling the production cost of dimethyl carbonate. important method. [0003] Currently, with figure 1 It is a widely used distillation and separation process of dimethyl carbonate and methanol, and its process flow is as follows: [0004] a) Sen...

AI Technical Summary

Problems solved by technology

In this production process, although the reactive distillation column (1) and the methanol distillation column (3) use the overhead gas of the pressurized distillation column as the heat source, the pressurized distillation column (2) needs to consume a large amount of steam to increase the heating capacity. Reaction temperature and pressure of pressure rectification column (2)

[0009] 2. High unit consumption of circulating water

In this process, the condenser (5) of the methanol rectification tower needs to consume a large amount of circulating water to cool the gas phase at the top of the tower, and also wastes a large amount of latent heat of condensation of the mixed gas of methanol and dimethyl carbonate (15);

[0010] 3. The existing methanol rectification tower has a conventional structure, and its rectification efficiency is low and the effect is not good

[0012] (1) The whole process of sampling, analysis, and reporting of results takes a long time, and it takes 100-120 minutes for each sample from sampling to reporting of results

(2), the whole operation process requires the full participation of 1-2 personnel

(3) It is impossible to realize high-density quality monitoring in the production process, the quality data has a strong hysteresis effect, and the response timeliness of the adjustment requirements of multiple production operations is poor

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