Low-pressure ethanol recovery device and method with triple effect rectification

Abstract

The invention discloses a low-pressure ethanol recovery device and method with triple effect rectification. The low-pressure ethanol recovery device with triple effect rectification comprises a first rectifying tower, a second rectifying tower, a third rectifying tower, a rectifying tower reboiler, a rectifying tower feed preheater, a condenser, a return tank, a dilute ethanol feed preheater, a temporary finished product storage tank and a finished product cooler. In the ethanol recovery method with triple effect rectification, by controlling the recovery of the finished ethanol in the second rectifying tower, the content of ethanol in tower bottom wastewater of the second rectifying tower is 5wt%-30wt%, the temperature of the tower bottom wastewater is 100-120 DEG C, and the working pressure of the third rectifying tower is 250-400kPa. The invention adopts the low-pressure triple effect rectification technique and reduces energy loss in the technical process, thus greatly reducing the energy consumption; and the operating pressure and temperature of the third rectifying tower are greatly reduced, and the requirements on the high temperature resistant and corrosion resistant properties of equipment are reduced, thereby reducing the equipment investment and the maintenance cost.

Description

technical field [0001] The invention relates to an ethanol recovery device and method, in particular to a low-pressure three-effect rectification ethanol recovery device and method, which are suitable for continuous recovery of dilute ethanol in light industry, food, pharmaceutical, chemical, electronic and other industries , especially suitable for dilute ethanol systems containing electrolyte components such as salts, and can distill and concentrate dilute ethanol from 5% to 75% v / v to 80% to 96% v / v. Background technique [0002] With the rapid development of light industry, food, pharmacy, chemical industry, electronics and other industries and the continuous expansion of production scale, the consumption of ethanol as an industrial solvent is also increasing. The traditional batch ethanol recovery tower can no longer meet the needs of large-scale production. [0003] The continuous rectification ethanol recovery unit is divided into single-effect rectification, double-...

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Problems solved by technology

[0005] (2) The investment of main heat exchange equipment is large: the inlet temperature of the waste water end of the feed preheater of the high-pressure tower reaches about 170 ° C ~ 180 ° C, the high temperature resistance of the gasket of the plate heat exchanger is higher, and liquid leakage is prone to occur

[0006] (3) Some dilute ethanol raw materials also contain electrolyte components such as sodium chloride, which will increase the temperature of the wastewater at the bottom of the tower, and the high temperature is more corrosive to the tower and heat exchange equipment, requiring more expensive materials

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