RU2239595C1 - Process of production hydrochloric acid from titanium-magnesium production effluent gases - Google Patents

Abstract

FIELD: nonferrous metallurgy.

SUBSTANCE: process comprises burning chlorine-containing gas in hydrocarbon-hydrogen fuel flame in presence of water steam to produce fuel gas. Process is characterized by that chlorine-containing gas and steam are preliminarily combined at volume ratio (1.1-4.0):1, burning of chlorine-containing gas in burning flame is carried out under anaerobic conditions, and volume ratio of steam and natural gas to chlorine in burning flame is (0.8-1.2):1.

EFFECT: increased content of hydrogen chloride in fuel gas allowing production of elevated-concentration aqueous hydrochloric acid therefrom.

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Description

The invention relates to non-ferrous metallurgy, in particular to the production of hydrogen chloride from waste chlorine-containing gases of titanium-magnesium production.

A known method of utilizing chlorine from waste gases of magnesium production (AS USSR No. 140211, publ. BI No. 15, 1962), comprising supplying chlorine-containing gases to a high-temperature flame of fuel (liquid or gaseous), after which the combustion products are furnace gases containing hydrogen chloride and chlorine are sent to the carnallite dehydration furnace (rotary kiln or fluidized bed furnace). Then, hydrogen chloride is absorbed by water, which allows to more fully purify gases from chlorine.

The disadvantage of this method is the low degree of capture of hydrogen chloride, which does not allow to obtain hydrogen chloride with a high concentration.

There is a method of neutralizing chlorine-containing gases (AS USSR No. 306861, publ. 06/21/1971, BI 20), which includes the supply of chlorine-containing gases to the combustion torch - a spray nozzle, which serves sprayed diesel fuel. Spraying is carried out with water vapor at a steam flow rate of 100 kg / min. The temperature in the combustion chamber is 1000 ° C.

The disadvantage of this method is that the use of diesel fuel is economically disadvantageous, the design process is time-consuming.

A known method of neutralizing chlorine-containing gases from titanium-magnesium production, including mixing chlorine-containing gases with air to a concentration of 200-480 chlorine per 1 m ^{3 of} air, supplying a chlorine-containing mixture to a carbon-containing fuel combustion torch, restoring it to hydrogen chloride during combustion, followed by utilization by chlorination and evaporation of the lime milk.

The disadvantage of this method is that the supply of air to the flame does not allow the production of high concentration hydrogen chloride.

A known method of producing hydrogen chloride (patent RU No. 2139237, publ. 10.10.1999), by the number of common features adopted for the closest analogue prototype and including the simultaneous supply of carbon-hydrogen fuel, air, chlorine-containing gas and water vapor to the furnace. In the furnace, chlorine is converted and a gas mixture is formed (flue gases) containing hydrogen chloride with a temperature of 1300-1600 ° С. In the heat exchanger, the gas mixture is cooled in two stages by air, first to a temperature of 750-800 ° C and then to a temperature of 450-500 ° C.

The disadvantage of this method is that to reduce the temperature of the flue gases add secondary air, this significantly increases the amount of flue gases and reduces the concentration of hydrogen chloride in them. At operating temperatures of the flue gases of 750-1150 ° C, the concentration of hydrogen chloride does not exceed 9-15%. With further processing of the flue gases at a given concentration of hydrogen chloride, hydrochloric acid of low concentration is obtained, which does not allow its further use in chemical production.

The technical result is aimed at eliminating the disadvantages of the prototype and at increasing the content of hydrogen chloride in the flue gases, which makes it possible to obtain hydrochloric acid of high concentration from them.

The technical result is achieved by the fact that the proposed method for producing hydrogen chloride from chlorine-containing exhaust gases of titanium-magnesium production, including the combustion of chlorine-containing gas in a carbon-hydrogen fuel flare in the presence of water vapor to produce flue gases and cooling them, is new, before being fed to the combustion torch chlorine-containing gases and water vapor are mixed at a volume ratio (1.1-4.0): 1, the combustion of chlorine-containing gas in the combustion torch is carried out without air supply, and Volumetric ratio of water vapor and natural gas to chlorine in the combustion torch is maintained at (0.8-1.2): 1.

It has been experimentally established that mixing chlorine-containing gases with water vapor makes it possible to intensify the combustion of chlorine, since in the presence of water the generation of H, O, OH radicals responsible for the combustion process occurs. This leads to an increase in the H / Cl ratio and allows a several-fold increase in the amount of chlorine supplied to combustion, which increases the concentration of hydrogen chloride in the flue gases.

It was experimentally established that the flow of water at a certain volumetric ratio to chlorine can reduce the process temperature due to the endothermic process

2Cl ₂ + 2H ₂ O = 4CHl + O ₂ -Q.

All these conditions, with the same dosage of chlorine in the combustion torch without dilution with secondary air, lead to an increase in the concentration of hydrogen chloride in the flue gases.

An indispensable condition for achieving a technical result is to maintain a certain volumetric ratio of water vapor and natural gas to chlorine equal to (0.8-1.2): 1, this allows you to increase the concentration of hydrogen chloride due to the full use of hydrogen ions in the mixture.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information and identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find a source characterized by features that are identical (identical) to all the essential features of the invention. The determination from the list of identified analogues of the prototype as the closest analogue in the totality of features made it possible to establish the set of distinguishing features that are essential for the applicant's technical result in the claimed method for producing hydrogen chloride from chlorine-containing exhaust gases of titanium-magnesium production set forth in the claims.

Therefore, the claimed invention meets the condition of "novelty."

To verify the compliance of the claimed invention with the condition “inventive step”, the applicant conducted an additional search for known solutions in order to identify signs that match the distinctive features of the claimed method from the prototype. The search results showed that the claimed invention does not follow explicitly from the prior art for the specialist, since the influence of the transformations provided for by the essential features of the claimed invention is not revealed from the prior art determined by the applicant to achieve a technical result. Therefore, the claimed invention meets the condition of "inventive step".

Examples of the method.

Example 1 (prototype)

Chlorine-containing gases of titanium-magnesium production in an amount of 1200 nm ³ / hour (in terms of 100% chlorine) are fed to the combustion torch of the furnace, where 750 nm ³ / hour of natural gas, air and water vapor are supplied. In the combustion chamber, chlorine is converted and a gas mixture containing hydrogen chloride is formed. The temperature in the reaction zone is 1300-1600 ° C. Get flue gases with a concentration of hydrogen chloride of 9.0%. After cooling, the flue gases are treated with milk of lime (100-150 g / dm ³ CaO) to obtain a solution of calcium chloride.

Example 2

Chlorine-containing gases of titanium-magnesium production in an amount of 1200 nm ³ / hour (in terms of 100% chlorine) are mixed with 500 nm ³ / hour of water vapor in the main pipeline of chlorine-containing gas by inserting a separate pipeline for water vapor. Chlorine-containing gases and water vapor are mixed at a ratio of chlorine: steam = 2.4 and fed to the furnace, where natural gas is burned in an amount of 500 nm ³ / h. The temperature in the reaction zone is 750 ° C. In this case, a volume ratio of a mixture of water vapor and natural gas to chlorine equal to 0.83 is formed in the combustion torch of the furnace. Get flue gases with a concentration of hydrogen chloride of 13.6%. After cooling, the flue gases are treated with milk of lime (100-150 g / dm ³ CaO) to obtain a calcium chloride solution or passed through an absorber filled with water to obtain hydrochloric acid of a given concentration.

Example 3

Chlorine-containing gases of titanium-magnesium production in an amount of 1200 nm ³ / hour (in terms of 100% chlorine) are mixed with 700 nm ³ / hour of water vapor in the main pipeline of chlorine-containing gas by inserting a separate pipeline for water vapor. Chlorine-containing gases and water vapor are mixed at a ratio of chlorine: steam = 1.7 and fed to the burner, where natural gas is burned in an amount of 400 nm ³ / h. The temperature in the reaction zone is 450 ° C. In this case, a volume ratio of a mixture of water vapor and natural gas to chlorine equal to 0.91 is formed in the combustion torch of the furnace. Get flue gases with a concentration of hydrogen chloride of 18%. After cooling, the flue gases are treated with milk of lime (100-150 g / dm ³ CaO) to obtain a calcium chloride solution or passed through an absorber filled with water to obtain hydrochloric acid of a given concentration.

Example 4

Chlorine-containing gases of titanium-magnesium production in an amount of 1200 nm ³ / hour (in terms of 100% chlorine) are mixed with 900 nm ³ / hour of water vapor in the main pipeline of chlorine-containing gas by inserting a separate pipe for water vapor. Chlorine-containing gases and water vapor are mixed at a ratio of chlorine: steam = 1.33 and fed to the burner, where natural gas is burned in an amount of 300 nm ³ / h. The temperature in the reaction zone is 450 ° C. In this case, a volume ratio of a mixture of water vapor and natural gas to chlorine equal to 1.0 is formed in the combustion flame of the furnace. Get flue gases with a concentration of hydrogen chloride of 26.4%. After cooling, the flue gases are treated with milk of lime (100-150 g / dm ³ CaO) to obtain a calcium chloride solution or passed through an absorber filled with water to obtain hydrochloric acid of a given concentration.

Example 5

Chlorine-containing gases of titanium-magnesium production in an amount of 1200 nm ³ / hour (in terms of 100% chlorine) are mixed with 1060 nm ³ / hour of water vapor in the main pipeline of chlorine-containing gas by inserting a separate pipeline for water vapor. Chlorine-containing gases and water vapor are mixed at a ratio of chlorine: steam = 1.13 and fed to the burner, where natural gas is burned in an amount of 220 nm ³ / h. The temperature in the reaction zone is 750 ° C. In this case, a volume ratio of a mixture of water vapor and natural gas to chlorine equal to 1.06 is formed in the combustion torch of the furnace. Get flue gases with a concentration of hydrogen chloride of 34.5%. After cooling, the flue gases are treated with milk of lime (100-150 g / dm ³ CaO) to obtain a calcium chloride solution or passed through an absorber filled with water to obtain hydrochloric acid of a given concentration.

Example 6

Chlorine-containing gases of titanium-magnesium production in an amount of 800 nm ³ / hour (in terms of 100% chlorine) are mixed with 450 nm ³ / hour of water vapor in the main pipeline of chlorine-containing gas by inserting a separate pipeline for water vapor. Chlorine-containing gases and water vapor are mixed at a ratio of chlorine: steam = 1.77 and fed to the burner, where natural gas is burned in an amount of 260 nm ³ / h. The temperature in the reaction zone is 750 ° C. In this case, a volume ratio of a mixture of water vapor and natural gas to chlorine equal to 0.88 is formed in the combustion torch of the furnace. Get flue gases with a concentration of hydrogen chloride of 17.3%. After cooling, the flue gases are treated with milk of lime (100-150 g / dm ³ CaO) to obtain a calcium chloride solution or passed through an absorber filled with water to obtain hydrochloric acid of a given concentration.

Example 7

Chlorine-containing gases of titanium-magnesium production in an amount of 800 nm ³ / hour (in terms of 100% chlorine) are mixed with 700 nm ³ / hour of water vapor in the main pipeline of chlorine-containing gas by inserting a separate pipeline for water vapor. Chlorine-containing gases and water vapor are mixed at a ratio of chlorine: steam = 1.14 and fed to the burner, where natural gas is burned in an amount of 150 nm ³ / h. The temperature in the reaction zone is 750 ° C. In this case, a volume ratio of a mixture of water vapor and natural gas to chlorine equal to 1.06 is formed in the combustion torch of the furnace. Get flue gases with a concentration of hydrogen chloride of 33%. After cooling, the flue gases are treated with milk of lime (100-150 g / dm ³ CaO) to obtain a calcium chloride solution or passed through an absorber filled with water to obtain hydrochloric acid of a given concentration.

Example 8

Chlorine-containing gases of titanium-magnesium production in an amount of 1200 nm ³ / hour (in terms of 100% chlorine) are mixed with 500 nm ³ / hour of water vapor in the main pipeline of chlorine-containing gas by inserting a separate pipeline for water vapor. Chlorine-containing gases and water vapor are mixed at a ratio of chlorine: steam = 2.4 and fed to the burner, where natural gas is burned in an amount of 500 nm ³ / h. The temperature in the reaction zone is 400 ° C. In this case, a volume ratio of a mixture of water vapor and natural gas to chlorine equal to 0.83 is formed in the combustion torch of the furnace. Receive flue gases with a concentration of hydrogen chloride of 10.5%. After cooling, the flue gases are treated with milk of lime (100-150 g / dm ³ CaO) to obtain a calcium chloride solution or passed through an absorber filled with water to obtain hydrochloric acid of a given concentration.

Example 9

Chlorine-containing gases of titanium-magnesium production in an amount of 1200 nm ³ / hour (in terms of 100% chlorine) are mixed with 900 nm ³ / hour of water vapor in the main pipeline of chlorine-containing gas by inserting a separate pipe for water vapor. Chlorine-containing gases and water vapor are mixed at a ratio of chlorine: steam = 1.33 and fed to the burner, where natural gas is burned in an amount of 300 nm ³ / h. The temperature in the reaction zone is 400 ° C. In this case, a volume ratio of a mixture of water vapor and natural gas to chlorine equal to 1.0 is formed in the combustion flame of the furnace. Get flue gases with a concentration of hydrogen chloride of 18%. After cooling, the flue gases are treated with milk of lime (100-150 g / dm ³ CaO) to obtain a calcium chloride solution or passed through an absorber filled with water to obtain hydrochloric acid of a given concentration.

As can be seen from examples (4, 5, 7), with an increase in the supply of water vapor due to a decrease in the content of natural gas, an increase in the concentration of hydrogen chloride in the flue gases occurs. At the same time, a decrease in the process temperature occurs, which allows to reduce the cost of expensive equipment.

Claims (1)

A method of producing hydrogen chloride from waste chlorine-containing gases of titanium-magnesium production, comprising burning chlorine-containing gas in a carbon-hydrogen fuel flame in the presence of water vapor to produce flue gases and cooling them, characterized in that the chlorine-containing gases and water vapor are mixed before being fed into the flame flame when the volume ratio (1.1-4.0): 1, the combustion of chlorine-containing gas in the flare is carried out without air supply, and the volume ratio of water vapor and natural gas to chl py in the combustion torch is maintained at (0.8-1.2): 1.