阅读说明：本技术 一种醋酸酐的生产工艺 (Production process of acetic anhydride ) 是由 薛永彬 王利 于 2021-09-09 设计创作，主要内容包括：本发明涉及一种醋酸酐的生产工艺,将醋酸配制成94％的裂解酸溶液,裂解酸经汽化并加入10％磷酸氢二铵,混合进入裂解炉,炉内在高温700～730℃、负压-0.06～-0.08MPa和催化剂的作用下进行裂解生成的乙烯酮、水和不凝性气体,水和未反应的醋酸经水冷、盐冷,分段冷却冷凝后被排出,同时被冷却的乙烯酮和不凝性气体进入吸收塔与塔内的醋酸进行吸收反应,乙烯酮与醋酸进行吸收反应后生成粗醋酐,不凝性气体进入后续吸收塔再进行后续的回收。本发明具有如下优点：能够有效提高原料转化率,从而进一步提高乙酸酐收率,提高生产效率。(The invention relates to a production process of acetic anhydride, which comprises the steps of preparing 94% of cracking acid solution from acetic acid, vaporizing the cracking acid, adding 10% of diammonium hydrogen phosphate, mixing, feeding the mixture into a cracking furnace, cracking at a high temperature of 700-730 ℃ and a negative pressure of-0.06-0.08 MPa in the furnace under the action of a catalyst to generate ketene, water and non-condensable gas, cooling the water and unreacted acetic acid by water and salt, cooling and condensing in sections, discharging, feeding the cooled ketene and non-condensable gas into an absorption tower to perform absorption reaction with the acetic acid in the tower, absorbing the ketene and the acetic acid to generate crude acetic anhydride, and feeding the non-condensable gas into a subsequent absorption tower to perform subsequent recovery. The invention has the following advantages: can effectively improve the conversion rate of raw materials, thereby further improving the yield of acetic anhydride and improving the production efficiency.)

1. A production process of acetic anhydride is characterized by comprising the following steps: preparing 94% of cracking acid solution from acetic acid, vaporizing the cracking acid, adding 10% of diammonium hydrogen phosphate, mixing, feeding the mixture into a cracking furnace, cracking ketene, water and non-condensable gas in the furnace at the high temperature of 700-730 ℃ under the action of a catalyst under the negative pressure of-0.06-0.08 MPa, cooling water and salt of the unreacted acetic acid by stages, cooling and condensing the water and unreacted acetic acid by stages, discharging the cooled ketene and non-condensable gas, feeding the ketene and non-condensable gas into an absorption tower to perform absorption reaction with the acetic acid in the tower, performing absorption reaction on the ketene and the acetic acid to generate crude acetic anhydride, and feeding the non-condensable gas into a subsequent absorption tower to perform subsequent recovery; when the concentration of the crude acetic anhydride reaches 85%, the crude acetic anhydride is sent into a rectifying tower for rectification, fractionated low boiling point returns to an absorption tower for absorption, a high boiling point part is extracted at regular time for centralized treatment, middle fraction is used as finished acetic anhydride, unabsorbed non-condensable gas is washed and absorbed through subsequent multi-stage circulation, and finally the middle fraction is exhausted out of a vacuum pump extraction system, a small amount of uncracked acetic acid and water generated by reaction are separated in a condensation process, namely weak acid is collected in a weak acid recovery tank through a gas-liquid separator, and the weak acid is recycled through a weak acid concentrating device and is reused.

2. The process for producing acetic anhydride according to claim 1, wherein: the catalyst is diammonium hydrogen phosphate.

Technical Field

The invention relates to the technical field of acetic anhydride production, in particular to a production process of acetic anhydride.

Background

Acetic anhydride is an organic substance having the chemical formula C₄H₆O₃Colorless transparent liquid, strong smell of acetic acid, acid taste, hygroscopicity, dissolving in chloroform and diethyl ether, slowly dissolving in water to form acetic acid, and reacting with ethanol to form ethyl acetate. Is inflammable and has corrosionSexual, lacrimatory.

The existing acetic anhydride production process has low raw material conversion rate, thus resulting in lower acetic anhydride yield and low production efficiency.

Disclosure of Invention

The invention aims to provide a production process of acetic anhydride, which aims to improve the conversion rate of raw materials and the yield of acetic anhydride and improve the production efficiency.

In order to solve the technical problems, the technical scheme provided by the invention is as follows: preparing 94% of cracking acid solution from acetic acid, vaporizing the cracking acid, adding 10% of diammonium hydrogen phosphate, mixing, feeding the mixture into a cracking furnace, cracking at the high temperature of 700-730 ℃ and under the negative pressure of-0.06-0.08 MPa in the furnace under the action of a catalyst to generate ketene, water and non-condensable gas, cooling the water and unreacted acetic acid by water and salt, cooling and condensing in sections, discharging, feeding the cooled ketene and non-condensable gas into an absorption tower to perform absorption reaction with the acetic acid in the tower, generating crude acetic anhydride after the absorption reaction of the ketene and the acetic acid, and feeding the non-condensable gas into a subsequent absorption tower to perform subsequent recovery; when the concentration of the crude acetic anhydride reaches 85%, the crude acetic anhydride is sent into a rectifying tower for rectification, fractionated low boiling point returns to an absorption tower for absorption, a high boiling point part is extracted at regular time for centralized treatment, middle fraction is used as finished acetic anhydride, unabsorbed non-condensable gas is washed and absorbed through subsequent multi-stage circulation, and finally the middle fraction is exhausted out of a vacuum pump extraction system, a small amount of uncracked acetic acid and water generated by reaction are separated in a condensation process, namely weak acid is collected in a weak acid recovery tank through a gas-liquid separator, and the weak acid is recycled through a weak acid concentrating device and is reused.

As an improvement: the catalyst is diammonium hydrogen phosphate.

The beneficial effects obtained by the invention are as follows: the process can effectively improve the conversion rate of the raw materials, thereby further improving the yield of the acetic anhydride and improving the production efficiency.

Description of the drawings:

FIG. 1 is a flow chart of a process for producing acetic anhydride according to the present invention.

Detailed Description

The present invention will be described in further detail with reference to specific examples.

Example 1: preparing 94% of cracking acid solution from acetic acid, vaporizing the cracking acid, adding 10% of diammonium hydrogen phosphate, mixing, feeding the solution into a cracking furnace, cracking at a high temperature of 700 ℃ and under a negative pressure of-0.06 MPa in the furnace under the action of a catalyst to generate ketene, water and non-condensable gas, cooling the water and unreacted acetic acid by water and cooling salt, cooling and condensing in sections, discharging the ketene, the non-condensable gas and the cooled ketene, the cooled non-condensable gas and the cooled non-condensable gas enter an absorption tower to perform absorption reaction with the acetic acid in the tower, the ketene and the acetic acid generate crude acetic anhydride after the absorption reaction, and the non-condensable gas enters a subsequent absorption tower to perform subsequent recovery; when the concentration of the crude acetic anhydride reaches 85%, the crude acetic anhydride is sent into a rectifying tower for rectification, fractionated low boiling point returns to an absorption tower for absorption, a high boiling point part is extracted at regular time for centralized treatment, middle fraction is used as finished acetic anhydride, unabsorbed non-condensable gas is washed and absorbed through subsequent multi-stage circulation, and finally the middle fraction is exhausted out of a vacuum pump extraction system, a small amount of uncracked acetic acid and water generated by reaction are separated in a condensation process, namely weak acid is collected in a weak acid recovery tank through a gas-liquid separator, and the weak acid is recycled through a weak acid concentrating device and is reused.

The catalyst is diammonium hydrogen phosphate.

Example 2: preparing 94% of cracking acid solution from acetic acid, vaporizing the cracking acid, adding 10% of diammonium hydrogen phosphate, mixing, feeding the solution into a cracking furnace, cracking at 730 ℃ and under-0.08 MPa in the furnace under the action of a catalyst to generate ketene, water and non-condensable gas, cooling the water and unreacted acetic acid by water and cooling the salt, cooling and condensing the water and unreacted acetic acid in sections, discharging the cooled ketene and non-condensable gas, feeding the ketene and non-condensable gas into an absorption tower to perform absorption reaction with the acetic acid in the tower, performing absorption reaction on the ketene and the acetic acid to generate crude acetic anhydride, and feeding the non-condensable gas into a subsequent absorption tower to perform subsequent recovery; when the concentration of the crude acetic anhydride reaches 85%, the crude acetic anhydride is sent into a rectifying tower for rectification, fractionated low boiling point returns to an absorption tower for absorption, a high boiling point part is extracted at regular time for centralized treatment, middle fraction is used as finished acetic anhydride, unabsorbed non-condensable gas is washed and absorbed through subsequent multi-stage circulation, and finally the middle fraction is exhausted out of a vacuum pump extraction system, a small amount of uncracked acetic acid and water generated by reaction are separated in a condensation process, namely weak acid is collected in a weak acid recovery tank through a gas-liquid separator, and the weak acid is recycled through a weak acid concentrating device and is reused.

The catalyst is diammonium hydrogen phosphate.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.