SU833470A1 - Method of producing hydrogen chloride - Google Patents

Description

(54) METHOD FOR OBTAINING CHLORIDE HYDROGEN

one

The invention relates to the production of hydrochloric acid from hydrochloric acid by the action of a dehydrating agent on it, namely concentrated sulfuric acid, and can be used in the production of chlorosulfonic acid and in the production of mineral fertilizers.

A known method of producing hydrogen chloride by mixing hydrochloric and concentrated sulfuric acids and withdrawing from the process waste 74-76% sulfuric acid 1.

The disadvantage of this method is the low product yield and significant contamination of the spent sulfuric acid with hydrogen chloride.

The purpose of the invention is to increase the product yield and decrease the content of hydrogen chloride in the spent sulfuric acid.

The goal is achieved by a method involving the mixing of hydrochloric and concentrated sulfuric acid supplied in an amount that ensures its concentration in a mixture of 80-85%, followed by dilution of the acid with water to 74-76 / o and air blowing, in an amount of

10-30% of the volume of produced hydrogen chloride, which allows to increase the yield of hydrogen chloride to 99.9% (against 93.7-98.4% in the known method), and thereby reduce the content of hydrogen chloride in the spent sulfuric acid to 0,002-0,02% (against 0, 4% B of the known method).

The chosen ratio of the amounts of hydrochloric and concentrated sulfuric acids supplied to the displacement is due to

O the need to obtain in the first stage of the process 80-85% sulfuric acid, which has the minimum solubility of HCI, with a change in the concentration of the initial components: hydrochloric acid from 20 to 32% by weight, HCI, sulfuric from 92.5

Claims (1)

5 to 98 wt.% H O. Reducing this ratio results in an acid at a first stage of the process with a concentration of less than 80%, the solubility of HCI in which increases dramatically, and, consequently, the yield of HC1 in the gas phase decreases. Increasing this ratio results in an unreasonably large consumption of sulfuric acid. Dilution of 80–85% sulfuric acid with water to a concentration of 74–76% is due to the need to achieve a temperature of 95–110 ° C as a result, since at this temperature the solubility of HCl in sulfuric acid is minimal. The amount of air per hot acid purge of 10–30% of the volume of hydrogen chloride produced is due to the following: its lower limit is limited by the fact that the partial pressure of HC1 vapor decreases slightly and this almost does not affect the solubility of HC1, and the upper limit is limited by the fact that this produces a dilute hydrochloric gas. Example 1. 1000 kg of hydrochloric acid, containing 27.5 wt. Of P / about HC1, and 8216.7 kg of sulfuric acid (283% of stoichiometry in the preparation of 740 / o-NgZO) containing 92.5 wt.%, Are mixed to 85.0 wt.% HaSO4, containing 0.062 wt.% HCI. The temperature then rises to 65 ° C. Next, 85.0% sulfuric acid is displaced from 1329, 2 kg of water at 121 ° C and purged with air in the amount of 68.9 nm or 29% by volume of the hydrochloric gas volume, thus obtaining 237.7 nm of hydrochloric gas containing 71 vol.% HC1, and 10,270.8 kg, -4 (ii sulfuric acid containing 0002 1-ich;.% HC1. The output of HC1 is 99.9- / P. PRI me R 2. 1000 kg of hydrochloric acid, containing 32.0 wt.V 1С1, and 4155.6 kg of sulfuric acid (lG: iyo from stoichiometry in obtaining 75.1% HaSO), containing 95, wt.% HjSOj, 1 is reduced to 82 , 6 wt.% HaSO4, containing 0.081 wt.% HCl, while the temperature rises to 69 ° C. Next, 82.6% purulent sulfuric acid is displaced from 477.8 kg of water and at a temperature of 104.5 ° C, air is blown in the amount of 39.9 nm or 16.9% by volume of the hydrochloric gas volume, thus obtaining 236.1 nm of hydrochloric gas containing 83 , 1 about / i HC1, and 5262.2 kg of 75.1% sulfuric acid, containing 0.011% by weight of HC1. The yield on HC1 is 99.8%. Example 3. 1000 kg of hydrochloric acid, containing 30.0 wt.% HC1, and 3111.1 kg of sulfuric acid (129% of stoichiometry when preparing 76% HS.SO ,,), containing 98% by weight HjjSO, are mixed up to 80% by weight HgSO ,, containing 0.105 weight. % HC1. The temperature then rises to 74 ° C. Next, 80.0% sulfuric acid is shifted from 200.6 kg of water and at a temperature of 99.2 ° C, air is blown in the amount of 20.6 nm or 10.1% by volume of the hydrochloric gas, while in the amount of 20.6 nm or 10.1% by volume of the volume of hydrochloric gas, thus obtaining 204.4 nm of hydrochloric gas containing 89.9% by volume of HC1 and 4011.7 kg of 76% sulfuric acid containing 0.02% by weight HC1. The yield of HC1 is 99.7%. The proposed method makes it possible to obtain a concentrated hydrochloric gas from hydrochloric acid with a concentration of 20–32 wt.% HC1, as well as from mixtures of hydrochloric and sulfuric acids with a content of 5–33% HC1 and up to 20% HiSO%, which are waste products of many industries. extracting HC1 from which by other means is difficult and at the same time producing spent 74- 76% sulfuric acid with a content of not more than 0.02% HC1. Such an acid can be used without prior purification in the production of mineral fertilizers and phosphoric acid. Claims of obtaining hydrogen chloride by displacing hydrochloric and concentrated sulfuric acids, characterized in that, in order to increase the yield of the product and reduce the content of hydrogen chloride in the spent sulfur acid, sulfuric acid is fed in an amount that ensures its concentration in a mixture of 80-85%, followed by dilution of the acid with water to a concentration of 74-76% and air blowing, h is in an amount of 10-30% by volume of produced hydrogen chloride. Sources of information taken into account in the examination 1. Guide for preparative inorganic chemistry. Ed. Mr. Brouwer. M., 1956, p. 151 (prototype).