阅读说明：本技术 一种萤石法生产无水HF精制的FTrPSA深度脱水除杂的分离与净化方法 (Separation and purification method for deep dehydration and impurity removal of FTrPSA refined by anhydrous HF produced by fluorite method ) 是由 汪兰海 钟娅玲 钟雨明 陈运 唐金财 蔡跃明 于 2020-12-16 设计创作，主要内容包括：本发明公开了一种萤石法生产无水HF精制的FTrPSA深度脱水除杂的分离与净化方法,涉及工业上萤石法生产无水氟化氢(AHF)精制过程中控制含水量为主的分离与净化方法,其主要步骤为,以萤石法制备无水氟化氢(AHF)生产过程中经冷凝后得到的粗HF气体为原料气,进入由两段变压吸附(PSA)组成的中温变压吸附工序,得到的精HF气体再进入由上下两段精馏组成的HF精馏工序,从中得到纯度大于99.99％、收率超过90％的AHF产品气,由此替代传统的精馏与脱气精馏工艺,实现了AHF深度脱水与除杂净化,填补了萤石法生产AHF工艺技术的空白。(The invention discloses a separation and purification method for deeply dehydrating and purifying FTrPSA (fluorine-doped silica gel resin) for refining anhydrous HF (hydrogen fluoride) produced by a fluorite method, and relates to a separation and purification method mainly for controlling water content in the refining process of Anhydrous Hydrogen Fluoride (AHF) produced by the fluorite method in industry.)

1. A separation and purification method for deeply dehydrating and removing impurities in FTrPSA refined by anhydrous HF produced by fluorite method is characterized by comprising the following procedures:

(1) medium-temperature pressure swing adsorption, controlling the temperature of raw material gas to be 50-80 ℃ and the pressure to be normal pressure or micro-positive pressure, entering a medium-temperature pressure swing adsorption process consisting of two sections of pressure swing adsorption, wherein each section of pressure swing adsorption consists of more than 2 adsorption towers, at least 1 adsorption tower is in the adsorption step, the other adsorption towers are in desorption steps of different stages including decompression, reverse release, vacuumizing, pressurizing or final charging, the raw material gas enters from the bottom of a first section of pressure swing adsorption 1# PSA adsorption tower, non-adsorption phase gas flowing out from the top of the adsorption tower in the adsorption step is refined HF gas, the condensed non-condensable gas returns to a condensation process or a tail gas absorption process in the process of preparing HF by a fluorite method, and the refined HF liquid formed after condensation enters an HF rectification process, so that desorbed gas of the adsorption tower 1# in the desorption step enters from the bottom of the adsorption tower of a second section of pressure swing adsorption 2# PSA, mixing the intermediate gas of the non-adsorption phase flowing out from the top of the 2# PSA adsorption tower in the adsorption step with the raw material gas and returning to the 1# PSA adsorption tower, mixing the concentrated gas flowing out from the bottom of the 2# PSA adsorption tower with the reaction gas generated by the rotary kiln and returning to a washing tower in the process of preparing AHF by the fluorite method, and further recovering effective components;

(2) HF rectification, the rectified HF liquid which is formed by condensation from the medium temperature pressure swing adsorption process enters a rectification tower of the HF rectification process, the rectification tower is composed of an upper section and a lower section of rectification, the rectified HF liquid enters from the top of the lower section of rectification or from the bottom of the upper section of rectification, light component impurity gas which is distilled from the top of the upper section of rectification tower returns to a tail gas absorption process in the process of preparing HF by a fluorite method, or noncondensable gas which is formed by condensing the bottom of the upper section of rectification or the top distillate of the lower section of rectification is AHF product gas and has the purity of more than or equal to 99.99 percent, the liquid which is formed after condensation is used as the reflux of the upper section or the lower section of rectification, the tower bottom fluid which is distilled from the bottom of the lower section of rectification and contains a small amount of heavy component impurity components, the noncondensable gas which is formed after condensation returns to the medium temperature pressure swing adsorption process, effective components are further recovered, and the liquid which is formed after condensation, returning to the condensation process of the fluorite method AHF preparation process.

2. The method for deeply dehydrating and purifying FTrPSA for refining anhydrous HF produced by fluorite method, as claimed in claim 1, wherein the two-stage PSA of the medium temperature pressure swing adsorption process comprises feeding raw material gas into a No. 1 PSA adsorption tower, feeding intermediate gas of non-adsorption phase gas flowing out from the top of the adsorption tower in the adsorption step directly into a No. 2 PSA adsorption tower, feeding non-adsorption phase gas flowing out from the top of the adsorption tower in the adsorption step as refined HF gas, returning the non-condensable gas after condensation to the condensation process or tail gas absorption process in the process of producing HF produced by fluorite method, feeding the refined HF liquid formed after condensation into HF rectification, mixing the desorbed gas flowing out from the bottom of the No. 1 PSA adsorption tower in the desorption step with the reaction gas flowing out from a rotary kiln or reactor for producing AHF by fluorite method, feeding the scrubbing tower, feeding the scrubbing liquid as sulfuric acid, adsorbing the desorbed gas flowing out from the No. 2 PSA in the desorption step, returning to the condensation process of the production process of preparing AHF by fluorite method.

3. The method for deep dehydration and purification of FTrPSA for anhydrous HF refining by fluorite process according to claim 1 or 2, wherein the adsorption tower in the medium temperature pressure swing adsorption process is filled with one or more of active alumina, silica gel or molecular sieve.

4. The method for deeply dehydrating and purifying FTrPSA for refining anhydrous HF produced by fluorite method according to claim 1 or 2, wherein the desorbed gas from the bottom of the 1# PSA adsorption tower in the medium-temperature pressure swing adsorption process can be used as the pressurized or final gas for the 2# PSA adsorption tower, or the non-adsorbed gas from the top of the 2# PSA adsorption tower can be used as the backfilled gas pressurized or final gas after the 1# PSA adsorption tower is vacuumized.

5. The method for deep dehydration and purification of FTrPSA for refining anhydrous HF produced by fluorite method according to claim 1 or 2, wherein the tail gas from the return of the HF rectification process to the fluorite method HF production process is absorbed by the tail gas, the absorbent is the liquid from the condensation process of the fluorite method AHF production process or the liquid from the condensation of the distillate from the lower stage rectification bottom of the HF rectification process, the liquid is sprayed from the upper part of the absorption tower, the liquid and the light component impurity gas from the upper stage rectification top of the HF rectification process entering from the bottom of the absorption tower are subjected to reverse mass transfer absorption, the formed absorption liquid is the fluosilicic acid solution and is output as a byproduct, and the non-condensable gas flowing out from the top of the absorption tower is directly discharged according to the discharge requirement.

6. The deep dehydration and purification method for FTrPSA refining in the fluorite process for anhydrous HF production according to claim 1 or 2, wherein the refined HF liquid inlet end of the HF rectification process is arranged at the bottom of the upper section or at the top of the lower section.

Technical Field

The invention relates to a separation and purification method mainly for controlling water content in the refining process of Anhydrous Hydrogen Fluoride (AHF) produced by a fluorite method in industry, in particular to a separation and purification method for FTrPSA (full temperature range pressure swing adsorption) deep dehydration impurity removal for producing AHF by the fluorite method.

Background

Hydrogen Fluoride (HF) is a basic raw material for fluorine chemical industry, and can be used for producing organic fluorine, inorganic fluorine salt and other substances such as fluorine-containing catalyst, fluosilicic acid, etc., wherein HF is increasingly used in organic fluorine fields such as refrigerants, surfactants, fluororubbers, fluorine coatings, fluorine-containing resins, fluorine-containing pesticides, high-purity fluorine resins, medical intermediates, etc., and particularly, high-purity anhydrous HF (ahf) has become one of the essential electronic grade chemical raw materials for etching, cleaning, deposition, etc. in the semiconductor production field.

The main methods for industrially preparing Anhydrous Hydrogen Fluoride (AHF) include fluorite method and fluorosilicic acid method, wherein the fluorite method is domestic dominant and is natural or artificial fluorite (CaF)₂) Phosphate rock (Ca)₁₀F₂(PO₄)₆) Apatite (Ca)₅(PO₄)₃F) And the like as raw materials, and adopts a rotary kiln, a gas-solid fluidized bed, a gas-liquid-solid fluidized bed or a batch process technical route. In China, Fluorite (CaF)₂) With sulfuric acid (H)₂SO₄) The rotary kiln reaction method is mainly characterized in that fluorite and sulfuric acid react in a rotary furnace reactor, and the obtained reaction gas is washed, condensed, rectified and degassed to obtain an AHF product, wherein the main factors influencing the purity of the AHF product comprise material pretreatment, material concentration and proportion, and the control of water content becomes one of key factors influencing the AHF quality. As HF and water are almost co-dissolved, the water content of the industrial traditional rough rectification and degassing rectification method is difficult to reach the level of less than 10-100 ppm, and the quality requirement of electronic grade AHF can not be met particularly.

The main purpose of the fluorite method for preparing AHF water control in the industry at present is to prevent corrosion, because water has advantages and disadvantages in the production process, the method is beneficial to balancing light and heavy components in crude HF materials, and further utilizes crude rectification and degassing rectification to reach AHowever, the water content in the AHF still exceeds 0.1%, and the AHF cannot be used as an ultra-pure AHF or an electronic grade AHF, so that the water control range of the crude HF is generally limited to 2-5% (w/w) when the AHF is applied as an industrial grade product. In order to achieve the water control target, water control is industrially implemented mainly from two technical paths of reaction feeding mixed acid water proportioning and associated acid water content reduction, but because of the limitation of factors such as fluctuation of reaction conditions, uneven concentration distribution and the like, the water content cannot be controlled frequently, so that the corrosivity is increased on the contrary, the rectification efficiency is further reduced, and the water content in the AHF product is seriously exceeded. Because the fluorite method mainly adopts sulfuric acid as a reactant and still uses the sulfuric acid as a washing liquid in the washing process, the condensed crude HF liquid enters a rectifying tower to remove heavy components such as sulfuric acid, water and the like, and then enters a degassing tower to remove sulfur dioxide (SO)₂) Silicon tetrafluoride (SiF)₄) When the light components are equal, the AHF product obtained from the bottom of the degassing and rectifying tower still contains trace light and heavy impurity components, especially the heavy component impurities such as water, sulfate ions and the like. Although the boiling point difference between water, sulfuric acid and HF is large, water and sulfuric acid cannot be completely separated from HF due to strong intersolubility and limited phase balance of rectification separation, and in order to avoid increase of corrosivity caused by over-standard water content in the production process, crude HF liquid containing 2-5% of water still limits the phase balance of rectification, so that an AHF product with higher dehydration and purification depth cannot be produced.

AHF purification has been reported to be carried out by an adsorption method in which the adsorbent is mostly a fluoride of an alkali metal, and chemical adsorption is selectively carried out by a chemical reaction between a metal fluoride and HF at a relatively low temperature to form a metal fluoride-HF complex, and then a decomposition reaction of the complex is carried out at a relatively high temperature to thereby effect desorption of HF from the adsorbent, and other impurities are not selectively present on the adsorbent to thereby effect separation and purification of HF. The chemical adsorption method is suitable for preparing chlorofluoroalkane (CFC), Hydrochlorofluorocarbon (HCFC), Hydrochlorofluorocarbon (HFC) and sulfuryl fluoride (SO) by fluorination reaction₂F₂) The selective adsorption and separation of HF by the product and the reaction gas mixtureAnd recovery, the effect is better, but the loss rate of the adsorbent is high. For containing water or sulfuric acid or SiF₄The crude HF or the refined HF obtained by the fluorite method can not effectively carry out deep dehydration and impurity removal because the adsorbent can also have chemical reaction with impurity components such as water and the like to cause the pulverization and the failure of the adsorbent to be serious. Therefore, the chemisorption method can hardly be effectively applied to the production of AHF by the fluorite method. The method is also one of the main reasons why deep dehydration and impurity removal purification of electronic grade AHF products cannot be produced in China at present, and is one of the important reasons that Japan limits export of electronic grade AHF to Korea due to the technical advantages of Japan in the trade dispute of electronic grade semiconductor chemicals which occurs in two countries of Han and Japan in 2019, and Japan is a very few countries which internationally possess the technology for preparing AHF with the purity of 99.9999-99.999999% (6N-12N).

Disclosure of Invention

The invention provides a separation and purification method for deep dehydration and impurity removal of FTrPSA (Full Temperature Range Pressure Swing Adsorption) refined by anhydrous HF (Hydrogen fluoride) produced by fluorite method, wherein the Full Temperature Range Pressure Swing Adsorption (Full English name: Full Temperature Range-Pressure Swing Adsorption, abbreviated as FTrPSA) is a method which is based on Pressure Swing Adsorption (PSA) and can be coupled with various separation technologies, and reaction gas generated by reaction in the process of preparing AHF by fluorite method and each component (HF is an effective component, H is an effective component) in non-condensable gas obtained by washing and condensing the reaction gas₂O、H₂SO₄、SO₂、SiF₄As the main impurity component) per se, the difference of adsorption/condensation/rectification separation coefficients and physicochemical properties under different pressures and temperatures, and two sections of medium-temperature pressure swing adsorption procedures are mainly coupled with condensation and HF rectification, so that adsorption and desorption in the medium-temperature pressure swing adsorption process are easy to match and balance for cyclic operation to carry out separation and purification, thereby realizing deep dehydration and impurity removal of HF:

the technical scheme adopted by the invention is as follows: a process for deeply dewatering and purifying FTrPSA from the raw gas generated by condensing the Anhydrous Hydrogen Fluoride (AHF) prepared by fluorite method includes such steps as providing raw gas containing 70% (v/v) or more of non-condensable gas (coarse Hydrogen Fluoride (HF) gasHF, and sulfuric acid (H)₂SO₄) Water (H)₂O), sulfur dioxide (SO)₂) Silicon tetrafluoride (SiF)₄) Wherein the water content is not more than 6% (v/v), the temperature is 20-60 ℃, and the pressure is normal pressure or micro-positive pressure.

The method comprises the following steps:

(1) medium-temperature pressure swing adsorption, wherein a feed gas is subjected to heat exchange to 50-80 ℃ and the pressure is normal pressure or micro-positive pressure, the feed gas enters a medium-temperature pressure swing adsorption process consisting of two sections of Pressure Swing Adsorption (PSA), each section of pressure swing adsorption consists of more than 2 adsorption towers, at least 1 adsorption tower is in an adsorption step, the other adsorption towers are in desorption steps of different stages including depressurization, reverse release, vacuumizing, pressurizing or final filling, the feed gas enters from the bottom of a first section of PSA (1# PSA) adsorption tower, the operating pressure of the 1# PSA is normal pressure or micro-positive pressure, the operating temperature is 50-80 ℃, non-adsorption phase gas flowing out from the top of the adsorption tower in the adsorption step is refined HF gas, the condensed non-condensable gas returns to a condensation process or a tail gas absorption process in the process of preparing HF by a fluorite method, and the refined HF liquid formed after condensation enters the next process, namely HF rectification, the desorption gas from the 1# PSA adsorption tower in the desorption step enters from the bottom of the adsorption tower of the second PSA (1# PSA), the operating pressure of the 2# PSA adsorption tower is normal pressure or slight positive pressure, the operating temperature is 50-80 ℃, the intermediate gas of a non-adsorption phase flowing out from the top of the 2# PSA adsorption tower in the adsorption step is mixed with the raw material gas and returns to the 1# PSA adsorption tower, and the concentrated gas flowing out from the bottom of the 1# PSA adsorption tower is mixed with the reaction gas generated by the rotary kiln and returns to the washing tower in the process of preparing AHF by the fluorite method, thereby further recovering effective components.

(2) HF rectification, the refined HF liquid which is formed by condensation from the medium temperature pressure swing adsorption process enters a rectification tower of the HF rectification process, the rectification tower is composed of an upper section of rectification and a lower section of rectification, the refined HF liquid enters from the top of the lower section of rectification or from the bottom of the upper section of rectification, light component impurity gas which is distilled from the top of the upper section of rectification tower returns to a tail gas absorption process in the process of preparing HF by a fluorite method, or noncondensable gas which is formed by condensing the bottom of the upper section of rectification or the top distillate of the lower section of rectification is AHF product gas with the purity of more than or equal to 99.99 percent, the liquid which is formed by condensation is used as the reflux of the upper section of rectification, the tower bottom fluid which is distilled from the bottom of the lower section of rectification and contains a small amount of heavy component impurity component, the noncondensable gas which is formed by condensation returns to the medium temperature pressure swing adsorption process, effective components are further recovered, and the liquid which is formed by condensation, returning to the condensation process of the fluorite method AHF preparation process.

Furthermore, the two-stage PSA in the medium temperature pressure swing adsorption process comprises the steps of feeding a feed gas into a No. 1 PSA adsorption tower, feeding an intermediate gas of a non-adsorption phase gas flowing out from the top of the adsorption tower in the adsorption step directly into a No. 2 PSA adsorption tower, feeding the non-adsorption phase gas flowing out from the top of the adsorption tower in the adsorption step as a refined HF gas, returning a non-condensable gas after condensation to a condensation process or a tail gas absorption process in the process of preparing HF by a fluorite method, feeding a refined HF liquid after condensation into HF rectification, mixing a desorption gas flowing out from the bottom of the No. 1 PSA adsorption tower in the desorption step with a reaction gas flowing out from a rotary kiln or a reactor for producing AHF by the fluorite method, feeding the desorption gas into a washing tower, wherein the washing liquid is sulfuric acid, and feeding the desorption gas flowing out from the bottom of the No. 2 PSA adsorption tower in the desorption step back to the condensation process for preparing AHF by the fluorite method, wherein the two-stage PSA adsorption combination is, Higher sulfuric acid conditions.

Furthermore, one or more of active aluminum oxide, silica gel and molecular sieve are filled in the adsorption tower in the medium-temperature pressure swing adsorption procedure.

Furthermore, the desorbed gas flowing out of the bottom of the 1# PSA adsorption tower in the medium-temperature pressure swing adsorption process can be used as a pressurized or final gas for the 2# PSA adsorption tower, or the non-adsorbed phase gas flowing out of the top of the 2# PSA adsorption tower can be used as a backfilled gas pressurized or final gas for the 1# PSA adsorption tower after being vacuumized.

Furthermore, in the tail gas absorption process returned to the fluorite method HF preparation process in the HF rectification process, the absorbent is liquid from the condensation process of the fluorite method AHF preparation process or liquid obtained by condensing distillate from the bottom of the lower rectification section of the HF rectification process, the absorbent is sprayed downwards from the upper part of the absorption tower, and is subjected to reverse mass transfer absorption with light component impurity gas entering from the bottom of the absorption tower and distilled from the top of the upper rectification section of the HF rectification process, the formed absorption liquid is a fluosilicic acid solution and is output as a byproduct, and the non-condensable gas flowing out from the top of the absorption tower meets the emission requirement and is directly discharged.

Furthermore, the refined HF liquid inlet end of the HF rectification process is arranged at the bottom of the upper section or the top of the lower section.

The invention has the beneficial effects that:

(1) the invention realizes the replacement of the refining process of AHF rectification and degassing rectification in the production process of preparing AHF by the traditional fluorite method, solves the problems that the AHF rectification is controlled by the regulation and control of the water content of the front-end procedure in the production process and the rectification is controlled by the phase balance of the water content, thereby realizing the technical requirement that the water content of the AHF product is less than 100 ppm;

(2) the invention utilizes the reaction gas generated in the reaction of preparing AHF by fluorite method and each component (HF is effective component, H is H) in the noncondensable gas obtained after washing and condensation₂O、H₂SO₄、SO₂、SiF₄As the main impurity component) per se, the adsorption/condensation/rectification separation coefficients and the differences of physical and chemical properties under different pressures and temperatures, and two sections of medium-temperature pressure swing adsorption procedures are mainly coupled with condensation and HF rectification, so that adsorption and desorption in the medium-temperature pressure swing adsorption process are easy to match and balance for cyclic operation to carry out separation and purification, thereby realizing deep dehydration and impurity removal of HF;

(3) the invention overcomes the problem of large adsorbent loss rate in the frequent cyclic operation process of adsorption and desorption caused by the prior chemical adsorption method that HF and the adsorbent are subjected to chemical (chelating) reaction at low temperature for adsorption and then are subjected to decomposition reaction at high temperature for desorption, and simultaneously, the invention can treat the adsorbent containing water or sulfuric acid or SiF₄The crude HF or the refined HF obtained by the fluorite method can not effectively carry out deep dehydration and impurity removal because the adsorbent in the existing chemical adsorption also can have chemical reaction with impurity components such as water and the like to cause the pulverization and the failure of the adsorbent to be serious, and the invention can avoid the defects that the adsorbent can not be effectively deeply dehydrated and purifiedThe phenomenon is avoided, and the service life of the adsorbent is long;

(4) the invention avoids the problems of large fluctuation of the middle temperature of the rectifying tower, incapability of meeting the requirements of the tower bottom temperature, poor rectifying effect caused by large fluctuation of HF concentration and the like in the pure rectifying process of the AHF refining process, firstly removes most of the main heavy component impurities by adopting two-stage PSA, so that the fluctuation of the HF concentration entering the HF rectifying process is small, and further realizes deep dehydration and impurity removal of the AHF product preparation by adopting an upper-lower two-stage rectifying mode;

(5) the invention can obtain high-purity AHF product, and return the material to front end washing or condensation through middle temperature pressure swing adsorption and HF rectification process, to recover HF, to improve the yield of AHF product by 90%, and realize tail gas emission standard through tail gas absorption process.

Drawings

FIG. 1 is a schematic flow chart of example 1 of the present invention;

FIG. 2 is a schematic flow chart of example 2 of the present invention;

fig. 3 is a schematic flow chart of embodiment 3 of the present invention.

Detailed Description

The present invention will be described in further detail in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

Example 1

As shown in FIG. 1, a separation and purification method for deep dehydration and impurity removal of FTrPSA refined in anhydrous HF production by fluorite method, wherein the raw material gas is non-condensable gas generated by condensation in the course of Anhydrous Hydrogen Fluoride (AHF) production by fluorite method, namely crude Hydrogen Fluoride (HF) gas, the HF concentration is 90% (v/v), and sulfuric acid (H) is₂SO₄) Is 2% (v/v), water (H)₂O) is 5% (v/v), sulfur dioxide (SO)₂) 1.5% (v/v), silicon tetrafluoride (SiF)₄) 1.5% (v/v), the temperature is 20-25 ℃, and the pressure is normal pressure;

the specific implementation process comprises the following steps of,

(1) medium-temperature pressure swing adsorption, wherein raw gas passes through a heat exchanger to 60-70 ℃, is pressurized to 0.2-0.3 MPa, enters a medium-temperature pressure swing adsorption process consisting of two sections of Pressure Swing Adsorption (PSA), wherein the number of the first section PSA (1# PSA) adsorption towers is 3, 1 adsorption tower is used for adsorption, the other 2 adsorption towers are respectively used for pressure reduction and vacuum pumping, and desorption steps of raw gas pressure charging and final charging are carried out, the raw gas enters from the bottom of the first section PSA (1# PSA) adsorption tower, the operating pressure of the 1# PSA is 0.2-0.3 MPa, the operating temperature is 60-70 ℃, non-adsorption phase gas flowing out from the top of the 1 adsorption tower in the adsorption step is refined HF gas, the non-condensable gas after condensation returns to the condensation process in the process of preparing HF by a fluorite method, the refined HF liquid formed after condensation enters the next process, namely HF rectification, and desorption gas flowing out from the bottom of the 1# PSA adsorption tower in the pressure reduction and vacuum pumping steps, after the pressure is increased to 0.2-0.3 MPa, the gas enters from the bottom of 1 adsorption tower in the adsorption step in a second-stage PSA (2# PSA) system consisting of 3 adsorption towers, the operating pressure of the 2# PSA adsorption tower is 0.2-0.3 MPa, the operating temperature is 60-70 ℃, the intermediate gas of a non-adsorption phase flowing out of the top of the 12 # PSA adsorption tower in the adsorption step is mixed with feed gas and returns to the 1# PSA adsorption tower to further recover an effective component HF, the concentrated gas flowing out of the bottom of the 1 PSA adsorption tower in the pressure reduction and vacuum pumping desorption step is mixed with reaction gas generated by a rotary furnace and returns to a washing tower in the process of preparing AHF by a fluorite method to further recover the effective component;

(2) HF rectification, wherein a rectified HF liquid which is formed by condensation from a medium-temperature pressure swing adsorption process enters a rectifying tower of an HF rectification process, the rectifying tower of the process is composed of an upper section and a lower section of rectification, the rectified HF liquid enters from the top of the lower section of rectification, the operating temperature of the upper section of rectifying tower is 15-25 ℃, and light component impurity gas which is distilled from the top of the upper section of rectifying tower mainly comprises SO₂、SiF₄The low boiling point impurity components are returned to the tail gas absorption procedure in the production process of preparing HF by a fluorite method, the non-condensable gas formed by condensing the bottom distillate rectified from the upper section is AHF product gas, the purity is more than or equal to 99.99 percent, the product gas yield is more than 90 percent,and the liquid formed after condensation is used as the reflux of the upper-stage rectification, the operating temperature of the lower-stage rectification is 25-100 ℃, the non-condensable gas formed after condensation of the tower bottom fluid containing a small amount of heavy component impurity components distilled from the bottom of the lower-stage rectification returns to the medium-temperature pressure swing adsorption process, the effective components are further recovered, the liquid formed after condensation returns to the condensation process of the fluorite method AHF preparation process, and the operating pressure of the HF rectification is 0.03-0.2 MPa.

Example 2

As shown in FIG. 2, based on example 1, the HF concentration in the feed gas was 75% (v/v), and sulfuric acid (H) was present₂SO₄) 4% of water (H)₂O) is 6%, sulfur dioxide (SO)₂) Is 6% silicon tetrafluoride (SiF)₄) 6% of the total amount of the catalyst, and the balance of the catalyst such as ammonia (NH)₃) Hydrogen chloride (HCl) and hydrogen (H)₂) When the total amount of low-boiling-point impurity components is 2%, the temperature is 20-25 ℃, the pressure is normal pressure, the feed gas enters a No. 1 PSA adsorption tower after being pressurized to 0.2-0.3 MPa, non-adsorption phase gas flowing out of 1 adsorption tower top in the adsorption step directly enters a No. 2 PSA adsorption tower, the non-adsorption phase gas flowing out of 1 adsorption tower top in the adsorption step is refined HF gas, the condensed non-condensable gas returns to the condensation process in the process of preparing HF by a fluorite method, the refined HF liquid formed after condensation enters an HF rectification process, desorption gas flowing out of 1 No. 1 PSA adsorption tower bottom in the desorption step is mixed with reaction gas flowing out of a rotary kiln for preparing AHF by the fluorite method and enters a washing tower, and the washing liquid is sulfuric acid (H) (sulfuric acid)₂SO₄) The desorbed gas flowing out from the bottom of 1# 2 PSA adsorption tower in the desorption step returns to the condensation process of the fluorite method AHF preparation process, and the two-stage PSA adsorption combination is suitable for the raw material gas with low HF content and water content and H content₂SO₄Higher working conditions.

Example 3

As shown in fig. 3, in the above-mentioned tail gas absorption step of the HF rectification step, which is returned to the fluorite process HF production process, in addition to example 1, the absorbent is a condensed liquid of the distillate from the bottom of the lower stage rectification in the HF rectification step, and is sprayed downward from the upper part of the absorption column, and is subjected to reverse mass transfer absorption with the light component impurity gas entering from the bottom of the absorption column and distilled from the top of the upper stage rectification in the HF rectification step, and the formed absorption liquid is a fluosilicic acid solution and is output as a by-product, and the non-condensable gas flowing out from the top of the absorption column is directly discharged when meeting the discharge requirement.

Example 4

As shown in fig. 1, on the basis of example 1, one or more of active alumina, silica gel and molecular sieve are filled in the adsorption tower in the medium temperature pressure swing adsorption process, wherein the filling quantity and distribution of three adsorbents depend on the HF concentration of the feed gas and the content of impurity components, and the filling quantity distribution of the adsorbents in the two-stage PSA adsorption tower is also different.

Example 5

As shown in fig. 1, in example 1, the desorbed gas flowing out of the bottom of the # 1 PSA adsorption column in the medium temperature pressure swing adsorption process can be used as the pressurized or final gas for the # 2 PSA adsorption column, or the non-adsorbed phase gas flowing out of the top of the # 2 PSA adsorption column can be used as the pressurized or final gas for the backfill gas after the # 1 PSA adsorption column is vacuumized.

Example 6

As shown in FIG. 1, in example 1, the refined HF liquid inlet of the HF rectification process is arranged at the bottom of the upper section or at the top of the lower section, depending on the presence of H in the feed gas₂O、H₂SO₄、SO₂、SiF₄The content of main impurity components.

It should be apparent that the above-described embodiments are only some, but not all, of the embodiments of the present invention. All other embodiments and structural changes that can be made by those skilled in the art without inventive effort based on the embodiments described in the present invention or based on the teaching of the present invention, all technical solutions that are the same or similar to the present invention, are within the scope of the present invention.