Method for producing ethanol by hydrogenation of acetic acid

Abstract

The invention provides a method for preparing ethanol by hydrogenation of acetic acid with low energy consumption, which comprises the following steps: (1) gas phase hydrogenation; (2) gas-liquid separation; (3) esterification reaction; (4) product refining: the liquid phase Product B is sent to the first rectification column to produce the first overhead fraction and the first bottom fraction, and the first overhead fraction is partially returned to the gas phase hydrogenation reactor; the first column still fraction is sent to the neutralization reactor ; The neutralized first bottom fraction is sent to the second rectification tower, separated into the second overhead fraction and the second bottom fraction, and the second overhead fraction is partly returned to the gas phase hydrogenation reactor In the process, part of it is recovered as a mixed solvent product; the second bottom fraction is sent to the third rectification column, and is separated into the third column bottom fraction containing water, acetate and butanol and the third column containing ethanol and water The top fraction, the ethanol content in the top fraction is 85-95wt%, and the acidity value is 0-25mg / L. The method can reduce energy consumption and improve the quality of ethanol products.

Description

technical field [0001] The present invention relates to a kind of method of producing ethanol, more specifically, relate to a kind of method of preparing highly selective ethanol product by acetic acid hydrogenation. Background technique [0002] Ethanol is the earliest and most widely used fatty alcohol, and it is also the main component of wine. At present, the industrial production methods of ethanol mainly include fermentation method and ethylene hydration method. Ethylene hydration method is developed along with the rise of petrochemical industry, including indirect hydration method and direct hydration method. Due to the increase of ethylene production cost in recent years, the ethylene process is basically in a state of suspension in my country. The main raw material of the fermentation method is crops (including corn, sugarcane, sorghum, cassava, rice, etc.), and ethanol is obtained by fermenting starch in the crops. [0003] The raw materials used by major ethano...

AI Technical Summary

Problems solved by technology

In these patents, acetic acid is generally removed first by rectification, which can reduce the material requirements in the subsequent separation, thereby reducing investment costs, but there are also some problems: ethanol and ethanol, which account for the vast majority of product quality Water needs to be vaporized, so the energy consumption of rectification and deacidification is extremely high, and the deacidification tower has a large size and high material requirements, and the investment cost is extremely high; and in the actual rectification separation, there may be a very small amount of In the case of acetic acid, fuel ethanol and industrial ethanol products have strict requirements on acidity, so the product is unqualified in the case of operational fluctuations

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