Method for semi-continuously preparing electronic-grade hydrogen chloride

Abstract

The invention discloses a method for semi-continuously preparing electronic-grade hydrogen chloride in the field of electronic gas preparation, which comprises the following steps: (1) introducing industrial hydrogen chloride into an adsorption system after the moisture content of the industrial hydrogen chloride is lower than 50ppm by using a cryogenic system; (2) deeply removing trace moisture in the hydrogen chloride by using an adsorption system, and introducing the hydrogen chloride into a filtering system after the moisture content in the hydrogen chloride is lower than 1ppm; (3) removing the pulverized adsorbent entrained in the anhydrous hydrogen chloride gas by using a filtering system, and then introducing the anhydrous hydrogen chloride gas into a feeding tank of a rectifying tower; (4) introducing anhydrous hydrogen chloride in the feeding tank of the rectifying tower into a heavy component removal tower, removing high-boiling-point impurities from a tower kettle, and introducing a tower top material into a light component removal tower; and (5) continuously emptying the top of the light component removal tower to remove light boiling point impurities, and opening an extraction valve and filling when the purity of the tower kettle material hydrogen chloride is more than 99.9995%. According to the method, equipment corrosion is reduced, the influence of light-component impurities on the product is avoided, the product quality is stable, and the yield and the market competitiveness are improved.

Description

Technical Field

[0001] The invention belongs to the field of electronic gas preparation, and in particular relates to a method for semi-continuously preparing electronic-grade hydrogen chloride. Background Art

[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. With the development of the industry, the requirements for electronic-grade hydrogen chloride are becoming more and more stringent. The presence of trace amounts of water, carbon oxides, hydrocarbons and other impurities is the core of process separation. Limited by the shortcomings of existing research and development, technology, processes, equipment and other aspects, improving the separation and purification technology of electronic-grade hydrogen chloride will help break through the technical barriers of high-purity electronic gas production and preparation, and help China's electronic chemicals industry layout.

[0003] Patent document CN112678776A discloses a method for distilling and purifying electronic-grade hydrogen chloride for preparing electronic-grade hydrogen chloride. However, this method does not remove water from the hydrogen chloride, resulting in water and hydrogen chloride combining to form hydrochloric acid, which is prone to corrode the distillation tower and its ancillary equipment, and also produces hydrogen, causing impurities to exceed the standard.

[0004] Patent document CN110255501A discloses a method for preparing electronic grade high-purity hydrogen chloride, which adopts continuous distillation to prepare electronic grade high-purity hydrogen chloride. This method ignores the reaction of hydrogen chloride with a distillation tower to produce light impurities such as hydrogen and enrich them at the top of the tower, resulting in poor stability of the product extracted from the top of the tower. Summary of the invention

[0005] The object of the present invention is to provide a method for semi-continuously preparing electronic grade hydrogen chloride.

[0006] To achieve the above object, the technical solution adopted by the present invention is: a method for semi-continuously preparing electronic grade hydrogen chloride, comprising the following steps: (1) After the water content of industrial hydrogen chloride is reduced to less than 50 ppm by using a cryogenic system, it is passed into the adsorption system; (2) Using an adsorption system to deeply remove trace amounts of water from hydrogen chloride, after the water content in hydrogen chloride is less than 1 ppm, it is passed into a filtration system; (3) using a filtration system to remove the powdered adsorbent carried by the anhydrous hydrogen chloride gas, and then passing it into the feed tank of the distillation tower; (4) The anhydrous hydrogen chloride in the feed tank of the distillation tower is passed into the heavy component removal tower, the high boiling point impurities are removed from the bottom of the tower, and the top material is passed into the light component removal tower; (5) The top of the light component removal tower is continuously emptied to remove light boiling point impurities. When the purity of hydrogen chloride in the bottom of the tower is above 99.9995%, the extraction valve is opened for filling.

[0007] Preferably, the cryogenic system adopts two-stage cooling, the temperature of the first-stage cooling medium is 0~7°C, the temperature of the second-stage cooling medium is -35~-30°C, and the moisture content in the low-temperature hydrogen chloride does not exceed 50ppm.

[0008] Preferably, the adsorbent is alumina or molecular sieve, the pressure of the adsorption system is 0-20 barg, and the water content in the anhydrous hydrogen chloride does not exceed 1 ppm.

[0009] Preferably, the filtration accuracy of the filtration system is 0.1-3 μm.

[0010] Preferably, the distillation tower feed buffer tank has a pressure of 0-20 barg and a volume of 1-5 m 3 .

[0011] Preferably, when the pressure of the feed buffer tank of the distillation tower exceeds 15 barg, the ratio of the feed flow rate of the heavy component removal tower to the feed flow rate of the cryogenic system is 1 to 1.5.

[0012] Preferably, the heavy component removal tower is operated continuously at an operating pressure of 20-30 barg.

[0013] Preferably, the light component removal tower is operated semi-continuously, with continuous production at the top and intermittent production at the bottom, and the operating pressure is 20-30 barg.

[0014] Preferably, the bottom of the light component removal tower is tested online, and hydrogen chloride is produced when the purity is detected to be above 99.9995%. If the test fails, the bottom of the tower is shut down for production.

[0015] Preferably, the bottom liquid level of the light component removal tower is 500-1000 mm. When the bottom liquid level exceeds 950 mm, the bottom valve to the circulation tank is opened; when the bottom liquid level is 500-600 mm, the bottom valve to the circulation tank is closed.

[0016] Due to the application of the above technical scheme, the present invention has the following advantages compared with the prior art: the semi-continuous method for preparing electronic-grade hydrogen chloride disclosed by the present invention introduces a deep cooling system and an adsorption system for deep dehydration, thereby reducing equipment corrosion; the use of a tower bottom extraction method avoids the influence of light component impurities such as hydrogen generated by the reaction of hydrogen chloride with the wall of the distillation tower on the product, and the tower bottom extraction is controlled by online analysis to ensure the stability of the quality of the electronic-grade hydrogen chloride product, thereby improving the yield and market competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention discloses a process flow chart for semi-continuous preparation of electronic grade hydrogen chloride.

[0018] Figure 2 It is the process flow diagram of the light component removal tower.

[0019] In the figure: 1-light component removal tower, 11-light component removal tower condenser, 12-light component removal tower reboiler, 13-light component removal tower kettle extraction valve, 14-light component removal tower kettle extraction valve to circulation tank, 2-circulation tank, 21-circulation tank gas phase removal light component removal tower valve, 22-circulation tank tower kettle discharge valve. DETAILED DESCRIPTION

[0020] Conclusion The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example

[0022] A method for semi-continuously preparing electronic grade hydrogen chloride comprises the following steps: (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 lower than 50 ppm, it is introduced into the adsorption system; (2) The trace water in the low-temperature hydrogen chloride is deeply removed by using the adsorption system. A moisture meter is set at the gas outlet of the adsorption system. After the water content in the anhydrous hydrogen chloride is detected to be less than 1ppm, it is passed into the filtration system; (3) using a filtration system to remove the powdered adsorbent carried by the anhydrous hydrogen chloride gas, and then passing it into the feed tank of the distillation tower; (4) The anhydrous hydrogen chloride in the feed tank of the distillation tower is passed into the heavy component removal tower, the high boiling point impurities are removed from the bottom of the tower, and the top material is passed into the light component removal tower; (5) The top of the light component removal tower is continuously emptied to remove light boiling point impurities. The bottom of the tower is equipped with an online purity detection system. When the purity of hydrogen chloride in the bottom of the tower is detected to be above 99.9995%, the extraction valve is opened for filling.

[0023] In the preferred implementation mode of this embodiment, the cryogenic system adopts two-stage cooling, the temperature of the first-stage cooling medium is 0~7°C, the temperature of the second-stage cooling medium is -35~-30°C, and the moisture content in the low-temperature hydrogen chloride does not exceed 50ppm.

[0024] In the preferred implementation mode of this 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.

[0025] In the preferred implementation mode of this embodiment, the filtration accuracy of the filtration system is 0.1~3μm.

[0026] In the preferred embodiment of this embodiment, the pressure of the distillation tower feed buffer tank is 0~20barg and the volume is 1~5m 3When the pressure of the buffer tank exceeds 15 barg, the ratio of the feed flow rate of the deheavy component tower to the feed flow rate of the cryogenic system is 1~1.5.

[0027] In the preferred implementation mode of this embodiment, the heavy component removal tower is operated continuously at an operating pressure of 20-30 barg.

[0028] In the preferred implementation mode of this embodiment, the light component removal tower is semi-continuously operated, the top of the tower is continuously produced, the bottom of the tower is intermittently produced, and the operating pressure is 20-30 barg.

[0029] In the preferred implementation manner of this embodiment, the bottom of the light component removal tower detects that the purity of hydrogen chloride is above 99.9995% and then produces it. If the detection is unqualified, the production is shut down.

[0030] In the preferred implementation mode of this embodiment, the tower bottom liquid level of the light component removal tower is 500-1000 mm. When the tower bottom liquid level exceeds 950 mm, the tower bottom decirculation tank valve is opened; when the tower bottom liquid level is 500-600 mm, the tower bottom decirculation tank valve is closed.

[0031] The hydrogen chloride raw material used in the embodiment of the present invention is directly synthesized from chlorine and hydrogen, wherein the hydrogen chloride content is 92.5%, and the impurities are mainly hydrogen, nitrogen, oxygen, carbon oxides, hydrocarbons, water, chlorine, etc. The present invention was verified and produced in a certain enterprise in Henan, and the production process is as follows: After the two-stage cryogenic system is turned on and the cooling medium circulates for 2 hours, industrial hydrogen chloride is compressed by the compressor at a speed of 5Nm 3 / h flow rate into the deep cooling system, and the outlet moisture content was detected to be 45ppm; by means of pressure difference, it was passed into the 10m high adsorption tower, and the outlet moisture content was detected to be 0.8ppm, and then passed into the distillation tower feed buffer tank; when the feed buffer tank liquid level is 800mm, the deheaving component tower feed is started, and when the tower bottom liquid level is 700mm, the tower bottom extraction is started, and the tower bottom extraction flow rate is controlled to be 0.05Nm 3 / h, the tower top is fed into the light component removal tower; when the liquid level of the light component removal tower reaches 700mm, the tower top is opened for emptying, and the tower top emptying flow rate is controlled at 0.4Nm 3 / h, and the hydrogen chloride in the tower bottom is extracted after it is detected that the purity meets the requirements; the product situation after testing and filling is shown in Table 1.

[0032] Table 1 Test results of electronic grade hydrogen chloride products after filling 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 The above are only 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 in the protection scope of the present invention.

Claims

1. A method for semi-continuously preparing electronic grade hydrogen chloride, comprising the following steps: (1) After the water content of industrial hydrogen chloride is reduced to less than 50 ppm by using a cryogenic system, it is passed into the adsorption system; (2) Using an adsorption system to deeply remove trace amounts of water from hydrogen chloride, after the water content in hydrogen chloride is less than 1 ppm, it is passed into a filtration system; (3) using a filtration system to remove the powdered adsorbent carried by the anhydrous hydrogen chloride gas, and then passing it into the feed tank of the distillation tower; (4) The anhydrous hydrogen chloride in the feed tank of the distillation tower is passed into the heavy component removal tower, the high boiling point impurities are removed from the bottom of the tower, and the top material is passed into the light component removal tower; (5) The top of the light component removal tower is continuously emptied to remove light boiling point impurities. When the purity of hydrogen chloride in the bottom of the tower is above 99.9995%, the extraction valve is opened for filling; The cryogenic system adopts two-stage cooling, the temperature of the first-stage cold medium is 0~7°C, and the temperature of the second-stage cold medium is -35~-30°C; the adsorbent used in the adsorption system is alumina or molecular sieve, and the pressure of the adsorption system is 0~20barg; the filtration accuracy of the filtration system is 0.1~3μm.

2. The method according to claim 1, characterized in that The pressure of the distillation tower feed buffer tank is 0~20barg; the volume is 1~5m 3 ; When the pressure of the distillation tower feed buffer tank exceeds 15 barg, the ratio of the feed flow rate of the heavy component removal tower to the feed flow rate of the cryogenic system is 1~1.

5.

3. The method according to claim 1, characterized in that The de-heavy component tower is operated continuously with an operating pressure of 20~30barg.

4. The method according to claim 1, characterized in that: The light component removal tower is operated semi-continuously, with continuous production at the top and intermittent production at the bottom. The operating pressure is 20~30barg.

5. The method according to claim 1, characterized in that The bottom of the light component removal tower is tested online. If the purity of hydrogen chloride is detected to be above 99.9995%, it will be produced. If the test fails, the production will be shut down.

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

7. 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 kettle of the light component removal tower.

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