Energy-saving process for rectifying alcohol by adopting heat integration of three rectifying columns

Abstract

The invention relates to an energy-saving process for rectifying alcohol by adopting heat integration of three rectifying columns, in particular to an energy-saving process for producing alcohol from fermented liquor through rectification. A whole alcohol rectification system at least comprises a first rectifying column, a second rectifying column and a third rectifying column as well as corollary equipment of the three rectifying columns. The operation energy consumption is greatly reduced through heat integration among the three rectifying columns and applications of other heat exchange and energy saving technology in the system. An optimized heat exchange system ensures a molecular sieve absorption dehydration system and the rectifying system to be organically united, thus improving the stability and flexibility of the whole rectifying system. The method has the following beneficial effects: the defects of the prior art are overcome; by the method, the operation energy consumption is reduced to 1.1 tons of steam per ton of high-quality edible alcohol and is reduced by more than 30% compared with the operation energy consumption in the currently advanced alcohol processes; and the method has obvious practicability and economic benefit.

Description

technical field [0001] The invention relates to an energy-saving process for alcohol rectification with heat integration in three refining towers, which is an energy-saving process for producing alcohol from fermented mash through rectification. Background technique [0002] With the shortage of oil, coal and other energy resources, environmental pollution, and greenhouse effect becoming more and more serious, energy saving and consumption reduction in alcohol and other industries have become the key to the survival and competitiveness of enterprises, and have received more and more attention from all aspects. [0003] At present, the process of producing alcohol (fuel ethanol, edible alcohol) from fermented mash mostly adopts the double-tower distillation method. This method has the disadvantage of high production energy consumption, which restricts the economy of alcohol industry production. [0004] Chinese patent CN 02148634.4 provides an ultra-pure ethanol refining pro...

AI Technical Summary

Problems solved by technology

Its biggest defect is that the ethanol / water gas phase mixture extracted from the side line of the crude distillation tower needs to provide energy for the low-pressure azeotropic rectification column. The crude distillation tower must extract as much gas phase side line as possible, so the rising gas phase in the crude distillation tower rarely enters Mass transfer and removal of light components at the top of the crude distillation tower and its top condenser, resulting in the side stream gas phase of the crude distillation tower containing more light component impurities being introduced into the low-pressure azeotropic distillation column, and the alcohol product is difficult to reach the high-grade product

Another defect is that the azeotropic alcohol extracted from the low-pressure azeotropic rectification tower directly enters the top reflux liquid of the high-pressure azeotropic rectification tower. The methanol in this azeotropic alcohol is not concentrated, so the high-pressure azeotropic rectification tower The concentration of methanol between the top of the tower and the side line of the product is basically the same, and the concentration of methanol in the side line alcohol product is inevitably high, and the alcohol product can only meet the standard of general-grade edible alcohol, but cannot reach the standard of high-grade products

In addition, the ethanol product is actually extracted from the side line of the low-pressure azeotropic distillation tower and the high-pressure azeotropic distillation tower.

Images