A method for semi-continuous production of electronic grade hydrogen chloride

Abstract

The application discloses a kind of semi-continuous preparation electronic grade hydrogen chloride in the field of electronic gas preparation method, comprising the following steps: (1) using deep cooling system, after the water content of industrial hydrogen chloride is less than 50ppm, pass into adsorption system;(2) using adsorption system, trace moisture in hydrogen chloride is deeply removed, after the water content in hydrogen chloride is less than 1ppm, pass into filtration system;(3) using filtration system, the pulverized adsorbent entrained in anhydrous hydrogen chloride gas is removed, then pass into rectification column feed tank;(4) anhydrous hydrogen chloride in rectification column feed tank is passed into heavy component removal column, high-boiling impurities are removed in column bottom, and top material is passed into light component removal column;(5) light component removal column top is continuously emptied to remove light-boiling impurities, when the purity of hydrogen chloride in column bottom material is 99.9995% or more, open the production valve, and fill.The method reduces equipment corrosion, avoids the influence of light component impurities on product, product quality is stable, improves yield and market competitiveness.

Description

Technical Field

[0001] This invention belongs to the field of electronic gas preparation, specifically relating to a semi-continuous method for preparing electronic-grade hydrogen chloride. Background Technology

[0002] Electronic-grade hydrogen chloride is one of the most widely used electronic gases in industries such as integrated circuits, flat panel displays, and new energy. As these industries develop, the requirements for electronic-grade hydrogen chloride are becoming increasingly stringent. The presence of impurities such as trace amounts of water, carbon oxides, and hydrocarbons is a key factor in the separation process. Limited by current research, technology, processes, and equipment, improving electronic-grade hydrogen chloride separation and purification technology will help overcome the technological barriers to the production of high-purity electronic gases and contribute to the industrial layout of China's electronic chemicals sector.

[0003] Patent document CN112678776A discloses a method for purifying electronic-grade hydrogen chloride by distillation, but this method does not remove water from the hydrogen chloride, causing water and hydrogen chloride to combine to form hydrochloric acid, which easily corrodes the distillation column and its auxiliary equipment, and at the same time generates hydrogen gas, causing impurities to exceed the standard.

[0004] Patent document CN110255501A discloses a method for preparing electronic-grade high-purity hydrogen chloride, which uses continuous distillation to prepare electronic-grade high-purity hydrogen chloride. This method ignores the reaction of hydrogen chloride with the distillation column to produce light impurities such as hydrogen, which are enriched at the top of the column, resulting in poor stability of the product taken from the top of the column. Summary of the Invention

[0005] The purpose of this invention is to provide a semi-continuous method for preparing electronic-grade hydrogen chloride.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is: a semi-continuous method for preparing electronic-grade hydrogen chloride, comprising the following steps:

[0007] (1) After the moisture content of industrial hydrogen chloride is reduced to less than 50 ppm using a cryogenic system, it is introduced into the adsorption system;

[0008] (2) Use an adsorption system to remove trace amounts of water from hydrogen chloride. Once the water content in hydrogen chloride is below 1 ppm, it is introduced into a filtration system.

[0009] (3) Use a filtration system to remove the powdered adsorbent entrained in the anhydrous hydrogen chloride gas, and then pass it into the feed tank of the distillation column;

[0010] (4) The anhydrous hydrogen chloride in the feed tank of the distillation column is fed into the de-heavy component column, the high-boiling-point impurities are removed from the bottom of the column, and the material at the top of the column is fed into the de-light component column.

[0011] (5) The top of the light component removal tower is continuously vented to remove light boiling point impurities. When the purity of hydrogen chloride in the bottom material is above 99.9995%, the outlet valve is opened for filling.

[0012] Preferably, the cryogenic system employs two-stage cooling, with the first-stage cooling medium having a temperature of 0~7℃ and the second-stage cooling medium having a temperature of -35~-30℃, and the moisture content in the low-temperature hydrogen chloride not exceeding 50ppm.

[0013] Preferably, the adsorbent is alumina or molecular sieve, the pressure of the adsorption system is 0~20 barg, and the moisture content in the anhydrous hydrogen chloride does not exceed 1 ppm.

[0014] Preferably, the filtration accuracy of the filtration system is 0.1~3μm.

[0015] Preferably, the pressure of the feed buffer tank for the distillation column is 0~20 barg, and the volume is 1~5 m³. 3 .

[0016] Preferably, when the pressure in the feed buffer tank of the distillation column exceeds 15 barg, the ratio of the feed flow rate of the deweighting column to the feed flow rate of the cryogenic system is 1 to 1.5.

[0017] Preferably, the debinding column is operated continuously at an operating pressure of 20-30 barg.

[0018] Preferably, the light component removal tower is operated in a semi-continuous manner, with continuous extraction from the top and intermittent extraction from the bottom, and the operating pressure is 20~30 barg.

[0019] Preferably, the bottom of the light component removal tower is monitored online. If the hydrogen chloride purity is detected to be above 99.9995%, the tower is collected; if the test fails, the collection is shut down.

[0020] Preferably, the bottom liquid level of the light component removal tower is 500~1000mm. When the bottom liquid level exceeds 950mm, the valve for sending the bottom liquid to the circulation tank is opened; when the bottom liquid level is 500~600mm, the valve for sending the bottom liquid to the circulation tank is closed.

[0021] Due to the application of the above technical solutions, the present invention has the following advantages compared with the prior art: The semi-continuous preparation method of electronic-grade hydrogen chloride disclosed in the present invention introduces a cryogenic system and an adsorption system for deep dehydration, reducing equipment corrosion; the use of bottom-collection avoids the influence of light component impurities such as hydrogen generated by the reaction of hydrogen chloride with the distillation column wall on the product; and the bottom-collection is controlled by online analysis to ensure the stability of the quality of electronic-grade hydrogen chloride products, thereby improving yield and market competitiveness. Attached Figure Description

[0022] Figure 1 This is a process flow diagram of the semi-continuous preparation of electronic-grade hydrogen chloride disclosed in this invention.

[0023] Figure 2 This is the process flow diagram of the light component removal tower.

[0024] In the diagram: 1-Light component removal tower, 11-Light component removal tower condenser, 12-Light component removal tower reboiler, 13-Light component removal tower bottom outlet valve, 14-Light component removal tower bottom outlet to circulation tank valve, 2-Circulation tank, 21-Circulation tank gas phase to light component removal tower valve, 22-Circulation tank bottom outlet valve. Detailed Implementation

[0025] The technical solutions of the present invention will now be clearly and completely described in conjunction with the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0026] Example

[0027] A semi-continuous method for preparing electronic-grade hydrogen chloride includes the following steps:

[0028] (1) Industrial hydrogen chloride is introduced into the cryogenic system. A moisture meter is installed at the gas outlet of the cryogenic system. After the moisture content in the low-temperature hydrogen chloride is detected to be less than 50 ppm, it is introduced into the adsorption system.

[0029] (2) The trace moisture in the low-temperature hydrogen chloride of the adsorption system is removed in depth. A moisture meter is installed at the gas outlet of the adsorption system. After the moisture content in the anhydrous hydrogen chloride is detected to be less than 1 ppm, it is introduced into the filtration system.

[0030] (3) Use a filtration system to remove the powdered adsorbent entrained in the anhydrous hydrogen chloride gas, and then pass it into the feed tank of the distillation column;

[0031] (4) The anhydrous hydrogen chloride in the feed tank of the distillation column is fed into the de-heavy component column, the high-boiling-point impurities are removed from the bottom of the column, and the material at the top of the column is fed into the de-light component column.

[0032] (5) The top of the light component removal tower is continuously vented to remove light boiling point impurities. The tower bottom is equipped with an online purity detection system. When the purity of hydrogen chloride in the tower bottom material is detected to be above 99.9995%, the outlet valve is opened for filling.

[0033] In this preferred embodiment, the cryogenic system employs a two-stage cooling system, with the first-stage cooling medium having a temperature of 0~7℃ and the second-stage cooling medium having a temperature of -35~-30℃, and the moisture content in the low-temperature hydrogen chloride not exceeding 50ppm.

[0034] In this preferred embodiment, the pressure of the adsorption system is 0~20 barg, and the water content in the anhydrous hydrogen chloride does not exceed 1 ppm.

[0035] In this preferred embodiment, the filtration accuracy of the filtration system is 0.1~3μm.

[0036] In this preferred embodiment, the pressure of the distillation column feed buffer tank is 0~20 barg, and the volume is 1~5 m³. 3 When the pressure in the buffer tank exceeds 15 barg, the ratio of the feed flow rate of the debinding column to the feed flow rate of the cryogenic system is 1 to 1.5.

[0037] In the preferred embodiment of this example, the debinding and recombining column is operated continuously at an operating pressure of 20-30 barg.

[0038] In the preferred embodiment of this example, the light component removal tower is operated in a semi-continuous manner, with continuous extraction from the top of the tower and intermittent extraction from the bottom of the tower, and the operating pressure is 20~30 barg.

[0039] In the preferred embodiment of this example, the bottom of the light component removal tower is sampled when the hydrogen chloride purity is detected to be above 99.9995%; if the test fails, the sampling is shut off.

[0040] In this preferred embodiment, the bottom liquid level of the light component removal column is 500-1000 mm. When the bottom liquid level exceeds 950 mm, the valve for sending the bottom liquid to the circulation tank is opened; when the bottom liquid level is 500-600 mm, the valve for sending the bottom liquid to the circulation tank is closed.

[0041] The hydrogen chloride raw material used in this invention is obtained by direct synthesis from chlorine and hydrogen, with a hydrogen chloride content of 92.5%. Impurities mainly include hydrogen, nitrogen, oxygen, carbon oxides, hydrocarbons, water, and chlorine. This invention was validated and produced in a company in Henan Province. The production process is as follows:

[0042] After the two-stage cryogenic system has been running for 2 hours to circulate the cooling medium, industrial hydrogen chloride is delivered at a rate of 5 Nm³ using a compressor. 3 A flow rate of [flow rate] / h was introduced into the cryogenic system, and the outlet moisture content was detected to be 45 ppm. Using pressure differential, the flow rate was then introduced into a 10m high adsorption tower, where the outlet moisture content was detected to be 0.8 ppm. The flow rate was then introduced into the feed buffer tank of the distillation column. Once the feed buffer tank level reached 800mm, the feed to the debinding column was started. Once the column bottom level reached 700mm, the column bottom discharge was initiated, with the discharge rate controlled at 0.05 Nm³. 3 / h, the liquid level in the light component removal column is introduced into the column top; when the liquid level in the light component removal column reaches 700mm, the top venting is started, and the venting flow rate is controlled at 0.4Nm. 3 / h, after detecting that the purity of hydrogen chloride in the tower bottom meets the requirements, it is collected; the product condition after filling is shown in Table 1.

[0043] Table 1. Test Results of Electronic Grade Hydrogen Chloride Products After Filling

[0044] Components HCl <![CDATA[H2]]> <![CDATA[N2]]> <![CDATA[O2+Ar]]> content 99.9995% ≤0.1ppm ≤0.1ppm ≤0.1ppm Components <![CDATA[CO2+CO]]> C1+C2 <![CDATA[Cl2]]> <![CDATA[H2O]]> content ≤0.5ppm ≤0.5ppm ≤0.1ppm ≤0.1ppm

[0045] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A semi-continuous method for preparing electronic-grade hydrogen chloride, comprising the following steps: (1) After the moisture content of industrial hydrogen chloride is reduced to less than 50 ppm using a cryogenic system, it is introduced into the adsorption system; (2) Use an adsorption system to remove trace amounts of water from hydrogen chloride. Once the water content in hydrogen chloride is below 1 ppm, it is introduced into a filtration system. (3) Use a filtration system to remove the powdered adsorbent entrained in the anhydrous hydrogen chloride gas, and then pass it into the feed tank of the distillation column; (4) The anhydrous hydrogen chloride in the feed tank of the distillation column is fed into the de-heavy component column, the high-boiling-point impurities are removed from the bottom of the column, and the material at the top of the column is fed into the de-light component column. (5) The top of the light component removal tower is continuously vented to remove light boiling point impurities. When the purity of hydrogen chloride in the bottom material is above 99.9995%, the outlet valve is opened and the tower is filled. The cryogenic system employs a two-stage cooling system, with the first-stage cooling medium having a temperature of 0~7℃ and the second-stage cooling medium having a temperature of -35~-30℃; the adsorbent used in the adsorption system is alumina or molecular sieve, and the pressure of the adsorption system is 0~20 barg. The electronic-grade hydrogen chloride contains ≤0.1ppm of moisture.

2. The method according to claim 1, characterized in that, The filtration accuracy of the filtration system is 0.1~3μm.

3. The method according to claim 1, characterized in that, The pressure of the feed buffer tank for the distillation column is 0~20 barg; the volume is 1~5 m³. When the pressure in the feed buffer tank of the distillation column exceeds 15 barg, the ratio of the feed flow rate of the deweighting column to the feed flow rate of the cryogenic system is 1~1.

5.

4. The method according to claim 1, characterized in that, The debinding column operates continuously at an operating pressure of 20-30 barg.

5. The method according to claim 1, characterized in that, The light component removal tower operates semi-continuously, with continuous top-end production and intermittent bottom-end production, and an operating pressure of 20-30 barg.

6. The method according to claim 1, characterized in that, The bottom of the light component removal tower is monitored online. If the hydrogen chloride purity is detected to be above 99.9995%, it is collected; if the test fails, the collection is shut down.

7. The method according to claim 1, characterized in that, When the bottom liquid level of the light component removal column is 500~1000mm, open the valve for the recirculation tank when the bottom liquid level exceeds 950mm; close the valve for the recirculation tank when the bottom liquid level is 500~600mm.

8. The method according to claim 1, characterized in that, A moisture meter is installed at the gas outlet of the cryogenic system; a moisture meter is installed at the gas outlet of the adsorption system; and a purity detection system is installed in the bottom of the light component removal tower.

Images