CN116081574A - A method for removing carbon dioxide in hydrogen chloride - Google Patents

Abstract

The invention discloses a method for removing carbon dioxide in hydrogen chloride, which comprises the following steps: step one: after hydrogen chloride is filtered and compressed, the hydrogen chloride enters the bottom of a first-stage reaction tower filled with saturated NaCL solution, the saturated NaCL solution in the first-stage reaction tower is contacted with the first-stage reaction tower, and the chlorine ions are saturated in the solution, so that the hydrogen chloride can not be dissolved again, and carbon dioxide is fused into the saturated NaCL solution; step two: the hydrogen chloride filtered by the primary carbon dioxide enters the bottom of a secondary reaction tower filled with a saturated NaCL solution, the saturated NaCL solution in the secondary reaction tower is contacted with the saturated NaCL solution, and the chlorine ions are saturated in the solution, so that the hydrogen chloride can not be dissolved again, and the carbon dioxide is fused into the saturated NaCL solution; and step three. In the invention, the hydrogen chloride is contacted with the saturated NaCL solution in the first-stage reaction tower and the second-stage reaction tower, and the chloride ions are saturated in the solution, so that the hydrogen chloride can not be dissolved again, and the carbon dioxide is fused into the saturated NaCL solution.

Description

A method for removing carbon dioxide in hydrogen chloride

technical field

The invention relates to the technical field of hydrogen chloride processing, in particular to a method for removing carbon dioxide in hydrogen chloride.

Background technique

Electronic grade high-purity hydrogen chloride is an important material for silicon wafer etching, passivation, epitaxy, vapor phase polishing, gettering and cleaning treatment in the production of integrated circuits. It can also be used in metal smelting, optical communication and scientific research and other fields. With the development of large-scale integrated circuits, the requirements for the purity of hydrogen chloride are getting higher and higher. In addition to having a purity of more than 99.999%, the requirements for the content of impurities are becoming more and more stringent, especially strict restrictions on hydrocarbons and carbon oxides. content to prevent the formation of C during silicon wafer processing. In the past, my country mostly imported electronic-grade hydrogen chloride from the United States, Japan and other countries, but in recent years, there have been many breakthroughs and developments in the development of chemical gases required by my country's electronics industry.

Contents of the invention

Aiming at the problems in the related art, the present invention proposes a method for removing carbon dioxide in hydrogen chloride, so as to overcome the above-mentioned technical problems in the existing related art.

Technical scheme of the present invention is realized like this:

According to one aspect of the present invention, a method for removing carbon dioxide from hydrogen chloride is provided.

The method for removing carbon dioxide in hydrogen chloride comprises the following steps:

Step 1: After the hydrogen chloride is filtered and compressed, it enters the bottom of the primary reaction tower equipped with a saturated NaCl solution, and the saturated NaCl solution in the primary reaction tower is in contact with it. Since chloride ions are saturated in the solution, the hydrogen chloride cannot be dissolved again, and Carbon dioxide is dissolved in saturated NaCl solution;

Step 2: The hydrogen chloride filtered by carbon dioxide once enters the bottom of the secondary reaction tower equipped with saturated NaCl solution, and the saturated NaCl solution in the secondary reaction tower is in contact with it. Since chloride ions are saturated in the solution, hydrogen chloride cannot be dissolved again. The carbon dioxide is dissolved in the saturated NaCl solution;

Step 3: Then, the hydrogen chloride that has been filtered twice will enter the bottom of the first-stage drying tower equipped with desiccant, and after removing most of the water through adsorption, it will come out from the top of the tower for deep dehydration;

Step 4: Then, enter the bottom of the secondary drying tower, remove a small amount of moisture and come out from the top of the tower, and the moisture content in the hydrogen chloride after removal is less than 0.5ppm;

Step 5: Then enter from the bottom of the adsorption tower 5 equipped with adsorbent, and come out from the top of the tower after removing carbon dioxide and a very small amount of water by adsorption, and the carbon dioxide content after adsorption is less than 2ppm.

Wherein, the desiccant in the step 3 and the step 4 and the adsorbent in the step 5 are all zeolite molecular sieves.

Wherein, the desiccant in both the step 3 and the step 4 is 13X zeolite molecular sieve, and the adsorbent in the step 5 is SSZ-13 zeolite molecular sieve.

Wherein, the desiccant in the step 3 and the step 4 and the adsorbent in the step 5 are treated with chlorine gas at 200° C. for two hours.

Wherein, in the step 1, after the hydrogen chloride is filtered and compressed, it enters the primary reaction tower at a flow rate of 1-5M3/h under the pressure of 0.3-0.6MPa and normal temperature.

Beneficial effect:

The hydrogen chloride in the present invention is in contact with the saturated NaCl solution inside both the primary reaction tower and the secondary reaction tower. Since chloride ions are saturated in the solution, hydrogen chloride cannot be dissolved again, and carbon dioxide is then incorporated into the saturated NaCl solution;

The desiccant and adsorbent used in the present invention are all treated with high-temperature chlorine gas at 200°C for 2 hours, the dust rate is reduced after treatment, and the strength is enhanced, which can meet the drying and adsorption requirements;

The adsorbent can be 5A, 13X, SSZ-13 zeolite molecular sieve and other adsorbents, preferably SSZ-13 zeolite molecular sieve, SSZ-13 has good carbon dioxide adsorption performance and is easy to regenerate;

The desiccant of the present invention can use 3A, 5A, 13X and other types of zeolite molecular sieves, preferably 13X molecular sieve desiccant. This desiccant does not react with hydrogen chloride, has large water absorption capacity, and has sufficient strength, and will not bring hydrogen chloride gas Metal ions and dust, easy to regenerate;

According to the moisture content and product purity requirements of different raw material products, multi-stage physical drying can be set to fully remove the moisture in the raw materials.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required in the embodiments. Obviously, the accompanying drawings in the following description are only some of the present invention. Embodiments, for those of ordinary skill in the art, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is a process flow diagram of a method for removing carbon dioxide in hydrogen chloride according to an embodiment of the present invention;

Fig. 2 is a schematic flowchart of a method for removing carbon dioxide in hydrogen chloride according to an embodiment of the present invention.

In the picture:

1. Primary reaction tower; 2. Secondary reaction tower; 3. Primary drying tower; 4. Primary drying tower; 5. Adsorption tower.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention belong to the protection scope of the present invention.

According to an embodiment of the present invention, a method for removing carbon dioxide in hydrogen chloride is provided.

As shown in Figure 1, a method for removing carbon dioxide in hydrogen chloride according to an embodiment of the present invention comprises the following steps:

Step S101, after the hydrogen chloride is filtered and compressed, it enters the bottom of the primary reaction tower 1 equipped with a saturated NaCl solution, and the saturated NaCl solution in the primary reaction tower 1 is in contact with it. Since the chloride ion is saturated in the solution, the hydrogen chloride cannot be dissolved again. , while carbon dioxide is dissolved in saturated NaCl solution;

Step S103, the hydrogen chloride filtered by carbon dioxide once enters the bottom of the secondary reaction tower 2 equipped with a saturated NaCl solution, and the saturated NaCl solution in the secondary reaction tower 2 is in contact with the saturated NaCl solution. Since the chloride ions are saturated in the solution, the hydrogen chloride can no longer dissolved, while carbon dioxide is dissolved in saturated NaCl solution;

Step S105, Step 3: Then, the hydrogen chloride filtered twice will enter the bottom of the first-stage drying tower 3 equipped with a desiccant, and after removing most of the water by adsorption, it will come out from the top of the tower for deep dehydration;

Step S107, then, enter the bottom of the secondary drying tower 4, remove trace moisture and come out from the top of the tower, and the moisture content in the hydrogen chloride after removal is less than 0.5ppm;

Step S109, then enter from the bottom of the adsorption tower 5 equipped with adsorbent, and come out from the top of the tower after removing carbon dioxide and a very small amount of moisture by adsorption, and the carbon dioxide content after adsorption is less than 2ppm.

Wherein, the desiccant in the step 3 and the step 4 and the adsorbent in the step 5 are all zeolite molecular sieves.

Wherein, the desiccant in both the step 3 and the step 4 is 13X zeolite molecular sieve, and the adsorbent in the step 5 is SSZ-13 zeolite molecular sieve.

Wherein, the desiccant in the step 3 and the step 4 and the adsorbent in the step 5 are treated with chlorine gas at 200° C. for two hours.

Wherein, in the step 1, after the hydrogen chloride is filtered and compressed, it enters the primary reaction tower 1 at a flow rate of 1-5 M3/h under the pressure of 0.3-0.6 MPa and normal temperature.

In summary, by means of the above-mentioned technical scheme of the present invention, hydrogen chloride among the present invention contacts with the saturated NaCl solution inside both primary reaction tower 1 and secondary reaction tower 2, because chloride ion is saturated in solution, hydrogen chloride cannot Redissolve, while carbon dioxide is dissolved in saturated NaCl solution;

The desiccant and adsorbent used in the present invention are all treated with high-temperature chlorine gas at 200°C for 2 hours, the dust rate is reduced after treatment, and the strength is enhanced, which can meet the drying and adsorption requirements;

The adsorbent can be 5A, 13X, SSZ-13 zeolite molecular sieve and other adsorbents, preferably SSZ-13 zeolite molecular sieve, SSZ-13 has good carbon dioxide adsorption performance and is easy to regenerate;

The desiccant of the present invention can use 3A, 5A, 13X and other types of zeolite molecular sieves, preferably 13X molecular sieve desiccant. This desiccant does not react with hydrogen chloride, has large water absorption capacity, and has sufficient strength, and will not bring hydrogen chloride gas Metal ions and dust, easy to regenerate;

According to the moisture content and product purity requirements of different raw material products, multi-stage physical drying can be set to fully remove the moisture in the raw materials.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the scope of the present invention. within the scope of protection.

Claims (5)

1. A method for removing carbon dioxide in hydrogen chloride, characterized in that, comprising: Step 1: after hydrogen chloride is filtered and compressed, enter the bottom of the primary reaction tower (1) that saturated NaCl solution is housed and enter, and the saturated NaCl solution in the primary reaction tower (1) contacts with, because chloride ion is saturated in solution, Hydrogen chloride cannot be dissolved again, while carbon dioxide is dissolved in saturated NaCl solution; Step 2: the hydrogenchloride that filters through carbon dioxide once, enters the bottom that the secondary reaction tower (2) that saturated NaCl solution is housed enters, and the saturated NaCl solution in the secondary reaction tower (2) contacts with, because chloride ion is saturated in solution , hydrogen chloride cannot be dissolved again, and carbon dioxide is dissolved in saturated NaCl solution; Step 3: Then, the hydrogen chloride filtered twice will enter the bottom of the first-stage drying tower (3) equipped with a desiccant, and after removing most of the water by adsorption, it will come out from the top of the tower for deep dehydration; Step 4: Then, enter the bottom of the secondary drying tower (4), and come out from the top of the tower after removing trace moisture, and the moisture content in the hydrogen chloride after removal is less than 0.5ppm; Step 5: Then enter from the bottom of the adsorption tower (5) equipped with adsorbent, absorb and remove carbon dioxide and a very small amount of water, and then come out from the top of the tower, and the carbon dioxide content after adsorption is less than 2ppm. 2. the method for removing carbon dioxide in hydrogen chloride according to claim 1 is characterized in that, the desiccant in the two of described step 3, the described step 4 and the adsorbent three in the described step 5 are all zeolite molecular sieves. 3. the method for removing carbon dioxide in hydrogen chloride according to claim 2, is characterized in that, the described desiccant in both described step 3 and described step 4 is 13X zeolite molecular sieve, and described in described step 5 The agent is SSZ-13 zeolite molecular sieve. 4. The method for removing carbon dioxide in hydrogen chloride according to claim 3, characterized in that, the desiccant in both the step three and the step four and the adsorbent three in the step five are all passed through 200 ℃ of high-temperature chlorine gas Process for two hours. 5. the method for removing carbon dioxide in hydrogen chloride according to claim 4, is characterized in that, in described step 1, after hydrogen chloride is filtered and compressed, under the pressure of 0.3-0.6MPa and normal temperature, with the flow rate of 1-5M /h Enter the primary reaction tower.

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