Method for preparing hydrochloric acid by utilizing hydrogen chloride gas in the process of producing potassium sulfate by Mannheim method

Abstract

The invention discloses a method for preparing hydrochloric acid by using hydrogen chloride gas in the process of producing potassium sulfate by a Mannheim method. After being cooled, the gas generated in a Mannheim furnace enters a spray tower for spray washing, and then enters a primary washing tower, a second defogger, a secondary washing tower, a third defogger, a third-stage falling film absorption tower and a fourth-stage washing tower in sequence after defogging treatment by a first defogger for continuous washing and emptying; a washing liquid 1 obtained by washing and absorbing the gas in the fourth-stage washing tower with deionized water enters the third-stage falling film absorption tower for washing and absorption to obtain hydrochloric acid A; environment-friendly tail gas iswashed by deionized water, a washing liquid sequentially enters the secondary washing tower, the primary washing tower and the spraying tower to wash the gas out of the Mannheim furnace, the sprayingwashing liquid in the spraying tower is discharged after reaching a certain concentration and neutralized by a KOH solution to obtain a potassium sulfate and potassium chloride mixed solution, and the mixed solution enters the Mannheim furnace after spray drying to produce potassium sulfate. The process is simple, and the obtained hydrochloric acid has high purity.

Description

technical field

[0001] The invention belongs to the field of chemical industry, relates to efficient recovery and utilization of hydrogen chloride, in particular to a method for preparing hydrochloric acid from hydrogen chloride gas in the process of producing potassium sulfate by Mannheim method. Background technique

[0002] The production of potassium sulfate by the Mannheim method is to use sulfuric acid and potassium chloride to react in a Mannheim furnace under high temperature conditions to produce potassium sulfate and hydrogen chloride, which is absorbed by water to produce hydrochloric acid, and potassium sulfate is the product after cooling. The Mannheim method is by far the most mature and reliable method with the most stable quality for the production of potassium sulfate.

[0003] However, because the Mannheim method produces a small amount of impurities such as water vapor, sulfuric acid gas, potassium sulfate dust, and potassium chloride dust in the hydrogen ...

Examples

Embodiment 1

[0041] The flow of deionized water for washing the gas in the four-stage scrubber is 14.8L / min, the internal circulation is 100L / min, and the output of hydrochloric acid A is 30.1 tons / day. The flow rate of deionized water for cleaning the environmentally friendly tail gas is 0.7L / min, and the output of mixed solids obtained from spraying waste liquid is 294kg / day.

[0042] The quality of detected hydrochloric acid A is shown in table 3 below:

[0043] project Sulfate (SO 4 2- ,%)

Fe 3+ (%)

HCl(%) color hydrochloric acid A 0.008 0.0005 32.1 colorless

[0044] table 3

[0045] The content of hydrogen chloride in the tail gas is: 5.17mg / m 3 , in line with environmental emission standards.

Embodiment 2

[0047] The flow of deionized water for washing the gas in the four-stage scrubber is 13.2L / min, the internal circulation is 115L / min, and the output of hydrochloric acid A is 28.0 tons / day. The flow rate of deionized water for cleaning the environmentally friendly tail gas is 2.6L / min, and the output of mixed solids obtained from spraying waste liquid is 299kg / day.

[0048] The hydrochloric acid quality after testing is shown in table 4 below:

[0049] project Sulfate (SO 4 2- ,%)

Fe 3+ (%)

HCl(%) color hydrochloric acid A 0.007 0.0005 32.6 colorless

[0050] Table 4

[0051] The content of hydrogen chloride in the tail gas is: 4.93mg / m 3 , in line with environmental emission standards.

Embodiment 3

[0053] The flow of deionized water for washing the gas in the four-stage scrubber is 14.8L / min, the internal circulation is 135L / min, and the output of hydrochloric acid A is 29.3 tons / day. The flow rate of deionized water for cleaning the environmentally friendly tail gas is 3.0L / min, and the output of mixed solids obtained from spraying waste liquid is 301kg / day.

[0054] The quality of detected hydrochloric acid A is shown in Table 5 below:

[0055] project Sulfate (SO42-,%) Fe3+(%) HCl(%) color hydrochloric acid A 0.007 0.0004 32.4 colorless

[0056] table 5

[0057] The content of hydrogen chloride in the tail gas is: 4.98mg / m 3 , in line with environmental emission standards.

technical field

[0001] The invention belongs to the field of chemical industry, relates to efficient recovery and utilization of hydrogen chloride, in particular to a method for preparing hydrochloric acid from hydrogen chloride gas in the process of producing potassium sulfate by Mannheim method. Background technique

[0002] The production of potassium sulfate by the Mannheim method is to use sulfuric acid and potassium chloride to react in a Mannheim furnace under high temperature conditions to produce potassium sulfate and hydrogen chloride, which is absorbed by water to produce hydrochloric acid, and potassium sulfate is the product after cooling. The Mannheim method is by far the most mature and reliable method with the most stable quality for the production of potassium sulfate.

[0003] However, because the Mannheim method produces a small amount of impurities such as water vapor, sulfuric acid gas, potassium sulfate dust, and potassium chloride dust in the hydrogen ...

Examples

Embodiment 1

[0041] The flow of deionized water for washing the gas in the four-stage scrubber is 14.8L / min, the internal circulation is 100L / min, and the output of hydrochloric acid A is 30.1 tons / day. The flow rate of deionized water for cleaning the environmentally friendly tail gas is 0.7L / min, and the output of mixed solids obtained from spraying waste liquid is 294kg / day.

[0042] The quality of detected hydrochloric acid A is shown in table 3 below:

[0043] project Sulfate (SO 4 2- ,%)

Fe 3+ (%)

HCl(%) color hydrochloric acid A 0.008 0.0005 32.1 colorless

[0044] table 3

[0045] The content of hydrogen chloride in the tail gas is: 5.17mg / m 3 , in line with environmental emission standards.

Embodiment 2

[0047] The flow of deionized water for washing the gas in the four-stage scrubber is 13.2L / min, the internal circulation is 115L / min, and the output of hydrochloric acid A is 28.0 tons / day. The flow rate of deionized water for cleaning the environmentally friendly tail gas is 2.6L / min, and the output of mixed solids obtained from spraying waste liquid is 299kg / day.

[0048] The hydrochloric acid quality after testing is shown in table 4 below:

[0049] project Sulfate (SO 4 2- ,%)

Fe 3+ (%)

HCl(%) color hydrochloric acid A 0.007 0.0005 32.6 colorless

[0050] Table 4

[0051] The content of hydrogen chloride in the tail gas is: 4.93mg / m 3 , in line with environmental emission standards.

Embodiment 3

[0053] The flow of deionized water for washing the gas in the four-stage scrubber is 14.8L / min, the internal circulation is 135L / min, and the output of hydrochloric acid A is 29.3 tons / day. The flow rate of deionized water for cleaning the environmentally friendly tail gas is 3.0L / min, and the output of mixed solids obtained from spraying waste liquid is 301kg / day.

[0054] The quality of detected hydrochloric acid A is shown in Table 5 below:

[0055] project Sulfate (SO42-,%) Fe3+(%) HCl(%) color hydrochloric acid A 0.007 0.0004 32.4 colorless

[0056] table 5

[0057] The content of hydrogen chloride in the tail gas is: 4.98mg / m 3 , in line with environmental emission standards.

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