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Process for preparing high purity hydrochloric acid by circularly absorbing hydrogen chloride by-product

A high-purity hydrochloric acid and hydrogen chloride technology, applied in the direction of chlorine/hydrogen chloride purification, chlorine/hydrogen chloride, etc., can solve the problems of difficulty in meeting the qualified standards of trace organic impurities, excessive hydrogen chloride tail gas, and high cost, and achieve good industrial application prospects and economic value Improvement, the effect of equipment investment increase

Inactive Publication Date: 2007-04-25
ZHEJIANG UNIV OF TECH
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  • Abstract
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AI Technical Summary

Problems solved by technology

Because the above-mentioned reaction often adopts the mode of reacting in an organic solvent under anhydrous conditions, the hydrogen chloride tail gas produced contains more organic impurities. If it is not treated, it will seriously affect the quality of by-product hydrochloric acid, thereby limiting its sales and sales. Application in industrial production
[0005] In the existing method, the process of traditional falling film absorption of by-product hydrochloric acid has also been improved, but it is mainly the method of absorbing first and then purifying. For example, Chinese patent CN2278522Y discloses a comprehensive absorption tower for chemical gases, but its structure is relatively relatively Complicated, high cost, and for the hydrogen chloride tail gas containing a lot of organic impurities, the device only uses falling film absorption and then cooling for gas-liquid separation may be difficult to meet the qualified standard for trace organic impurities
People such as Zhang Quanxing adopt the method (Chinese patent CN2278522Y) that absorbs by-product hydrochloric acid after first absorbing by-falling film, then uses macroporous resin to by-product hydrochloric acid to remove organic impurities, but this method will contain more hydrogen chloride tail gas containing organic impurities. The amount of macroporous resin is greatly increased. For the low-priced by-product hydrochloric acid, this method has certain limitations in industrial application.

Method used

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  • Process for preparing high purity hydrochloric acid by circularly absorbing hydrogen chloride by-product

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Experimental program
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Effect test

Embodiment 1

[0027] The equipment installation is shown in Figure 1. The main equipment models and specifications are as follows: (1) Snake tube glass condenser, model LNQ, 5m 2 ×2, produced by Changshu Deshun Chemical Equipment Co., Ltd.; (2) Adsorption tower, customized, material: reinforced polypropylene, specification: φ60cm×h200cm, built-in granular activated carbon 50Kg, model: ZS-15 granular activated carbon for solvent recovery, Manufactured by Nanjing Zhengsen Chemical Industry Co., Ltd.; (3) YKX round hole graphite falling film absorber, produced by Changzhou Fuhua Chemical Heat Exchange Equipment Co., Ltd.

[0028] The hydrogen chloride tail gas comes from the synthesis section of isopropyl isocyanate, and the reaction solvent is o-dichlorobenzene, which is reacted three times. Benzene 120L. The freezing medium of the shallow cold circulation system is ethanol, and the temperature is -10°C.

[0029] Including the following process steps:

[0030] (1) Shallow cold separation: ...

Embodiment 2

[0036] The equipment installation is shown in Figure 1. The main equipment models and specifications are as follows: (1) Snake tube glass condenser, model LNQ, 5m 2×2, produced by Changshu Deshun Chemical Equipment Co., Ltd.; (2) Adsorption tower, customized, material: reinforced polypropylene, specification: φ60cm×h200cm, built-in granular activated carbon 50Kg, model: ZS-15 granular activated carbon for solvent recovery, Produced by Nanjing Zhengsen Chemical Industry Co., Ltd.; (3) Modified graphite polypropylene falling film absorber, model: SPX-10-A, produced by Zhejiang Jiande Science and Technology Experimental Factory.

[0037] The hydrogen chloride tail gas comes from the synthesis section of isopropyl isocyanate, and the reaction solvent is o-dichlorobenzene, which is reacted three times. Benzene 120L. The freezing medium of the shallow cold circulation system is ethanol, and the temperature is -10°C.

[0038] Including the following process steps:

[0039] (1) Sha...

Embodiment 3

[0045] Equipment and its installation are the same as in Embodiment 2. The hydrogen chloride tail gas comes from the synthesis section of phenyl isocyanate, and the solvent used is chlorobenzene, which is reacted twice, and the feeding amount of each reaction is: 93Kg of aniline, 100Kg of bis(trichloromethyl)carbonate, 3Kg of tetrabutylurea, Chlorobenzene 250L; the freezing medium of the shallow cold circulation system is ethanol, and the temperature is -25°C.

[0046] Including the following process steps:

[0047] (1) Shallow cold separation: the hydrogen chloride tail gas from the phenyl isocyanate synthesis section is condensed through a two-stage coiled glass condenser with -25°C freezing medium ethanol in the jacket, and then passed through a gas-liquid separator to remove large Part of the high boiling point organic impurities chlorobenzene;

[0048] (2) Gas phase adsorption: remove the gas containing a small amount of organic impurities from the gas-liquid separator ...

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Abstract

The invention discloses a preparing method of high-purity alcaine technology through circulating and adsorbing by-product of hydrogen chloride, which comprises the following steps: aerating hydrogen chloride gas with organic impurity in the condenser at -10- -40 deg.c and gas-liquid separator; adsorbing gas with little impurity through active particle charcoal; aerating adsorbed gas into one-grade and two-grade graphite falling-film; adsorbing through pure water to obtain the high-purity alcaine; adsorbing non-adsorbed hydrogen chloride through cold water; putting hydrogen chloride and diluted acid in the graphite polypropylene falling-film adsorbing tower into cooling groove; utilizing circulating pump to transmit the inlet of one-grade falling-film adsorbing tower; circulating the adsorption.

Description

(1) Technical field [0001] The invention relates to a clean production process for the preparation of high-purity hydrochloric acid by cyclically absorbing hydrogen chloride by-products, especially for bis(trichloromethyl)carbonate to replace phosgene, thionyl chloride, phosphorus oxychloride, phosphorus pentachloride, etc. The green chemical technology is a clean production process for the preparation of high-purity hydrochloric acid by circulating and absorbing hydrogen chloride entrained with benzene, halogenated hydrocarbons and other organic solvents produced in chlorination and acyl chloride reactions. (2) Background technology [0002] High-purity hydrochloric acid is an important industrial raw material, which is used in chemical, metallurgical and other industries, and its usage in food and pharmaceutical industries is also increasing day by day. [0003] A large amount of hydrogen chloride tail gas is produced in many chemical productions. If the tail gas is compre...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B7/07C01B7/01
Inventor 苏为科李振华
Owner ZHEJIANG UNIV OF TECH
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