Dehydration device for hydrogen chloride gas

Abstract

The utility model discloses a hydrogen chloride gas dehydration device, which comprises: a heat exchanger, which is externally connected with the introduction of undehydrated hydrogen chloride gas and is used for deep condensation of the hydrogen chloride gas; the demister is communicated with the heat exchanger, and the demister is used for demisting the condensed hydrogen chloride gas; the cracking kettle is communicated with the demister, and the cracking kettle is used for cracking the demisted hydrogen chloride gas to form a crude monomer. The graphite condenser is additionally arranged before the hydrogen chloride gas enters the demister for deep condensation, and the temperature is controlled to be about 10 DEG C, so that a part of moisture in the hydrogen chloride gas is condensed and then discharged, and the moisture content of the gas before the hydrogen chloride gas enters the demister is effectively reduced; therefore, the dehydration effect on hydrogen chloride gas is improved.

Description

Technical Field

[0001] This application relates to the technical field of gas dehydration, and particularly to a dehydration device for hydrogen chloride gas. Background Art

[0002] Currently, hydrogen chloride gas has a wide range of applications in industry, especially in industries such as chemical engineering, pharmaceuticals, and semiconductor manufacturing. Since hydrogen chloride gas usually contains moisture, and the presence of moisture may have an adverse impact on downstream processes and equipment. For example: 1. Moisture will reduce the purity of the product, affecting the quality and performance of the final product; 2. High-humidity hydrogen chloride gas is prone to form acid mist or ice crystals under low-temperature conditions, blocking equipment such as pipelines, reactors, and distillation columns, resulting in production failures; 3. When in contact with certain materials, the presence of water will accelerate the corrosion process, increasing equipment maintenance costs and safety hazards; 4. During the cracking reaction process, the presence of water in the HCl gas affects the reaction efficiency, resulting in a high-boiling content greater than 40% in the cracked product monomer and a relatively high venting volume; 5. It causes frequent leakage of the internal reflux condenser, resulting in a high temperature at the top of the tower and a high-boiling content of the cracked product, affecting the quality of the monomer.

[0003] In the cracking process of the related technology, the high-boiling substances are preheated by a high-boiling substance preheater and then enter the high-boiling reaction kettle. At the same time, hydrogen chloride gas enters the high-boiling reaction kettle, and the metered catalyst is quantitatively added into the reaction kettle. After mixing with the high-boiling substances in the kettle, a reaction occurs at a certain temperature to generate a crude monomer. Due to the relationship between temperature and boiling point, it gradually vaporizes. After passing through the cracking tower section and being condensed by the internal reflux condenser, a part of the gas phase is condensed into a liquid phase as the internal reflux liquid and flows back into the tower, and a part of the uncondensed gas phase is condensed by the reaction primary condenser and the secondary condenser. The condensed liquid is a crude monomer mixture and enters the extraction tank, and is sent to the crude monomer tank in the tank area by the crude monomer transfer pump. Therefore, the non-reactive high-boiling substances are enriched after a long time. After the reaction in the cracking kettle deteriorates, they are discharged from the bottom of the high-boiling reaction kettle to the reaction residue tank and discharged as residue for external sale. During the reaction process, the hydrogen chloride contains water, and there is a phenomenon of blockage of the hydrogen chloride pipeline distributor in the reaction kettle, resulting in poor reaction efficiency. The water-containing hydrogen chloride gas is prone to corrode the internal reflux condenser, thus easily causing equipment leakage. Summary of the Utility Model

[0004] The purpose of this application is to provide a dehydration device for hydrogen chloride gas to effectively reduce the water content in hydrogen chloride gas.

[0005] To achieve the above object, the technical solution adopted in this application is as follows: Provide a dehydration device for hydrogen chloride gas, including: a heat exchanger, which is externally connected to the introduction of the un-dehydrated hydrogen chloride gas, and the heat exchanger is used for deeply condensing the hydrogen chloride gas; a demister, which is connected to the heat exchanger, and the demister is used for removing mist from the condensed hydrogen chloride gas; a cracking kettle, which is connected to the demister, and the cracking kettle is used for cracking the hydrogen chloride gas after removing mist to form crude monomers.

[0006] As a preference, the demister includes: a primary demister, one end of the primary demister is connected to the heat exchanger; a secondary demister, one end of the secondary demister is connected to the primary demister, and the other end of the secondary demister is connected to the cracking kettle.

[0007] As another preference, the primary demister is provided with a wire mesh demisting filter element, and the wire mesh demisting filter element is used for aggregating and intercepting the droplets in the hydrogen chloride gas to enrich the droplets to the bottom of the primary demister.

[0008] Further preferably, the secondary demister is provided with a fiber filter element. The hydrogen chloride gas dehydrated by the primary demister enters the secondary demister, and the droplets in the hydrogen chloride gas are coalesced through the fiber filter element to be deposited at the bottom of the secondary demister.

[0009] Further preferably, the dehydration device further includes a liquid storage tank. The bottom of the primary demister is connected to the bottom of the secondary demister to the liquid storage tank; wherein, the droplets in the hydrogen chloride gas aggregated by the primary demister and the secondary demister are introduced into the liquid storage tank for storage.

[0010] Further preferably, a plurality of the wire mesh demisting filter elements are arranged inside the primary demister.

[0011] Furthermore, the wire mesh demisting filter element includes: a first wire mesh demisting filter element and a second wire mesh demisting filter element, and the first wire mesh demisting filter element and the second wire mesh demisting filter element are arranged at intervals along the climbing direction of the hydrogen chloride gas.

[0012] Furthermore, the heat exchanger is a graphite heat exchanger.

[0013] Furthermore, the air inlet of the primary demister is arranged at the bottom of the primary demister, the air outlet of the primary demister is arranged at the top of the primary demister, and the wire mesh demisting filter element is arranged in the middle of the primary demister; wherein, the hydrogen chloride gas enters the primary demister from the air inlet, and after the hydrogen chloride gas climbs through the wire mesh demisting filter element, it enters the secondary demister from the air outlet.

[0014] Preferably, the wire mesh demisting filter element is woven in a warp and weft manner, and the wire mesh demisting filter element is provided with corrugations at a certain angle.

[0015] Compared with the prior art, the beneficial effects of the present application are as follows:

[0016] Before the hydrogen chloride gas enters the demister, a graphite condenser is added for deep condensation, and the temperature is controlled to about 10 degrees Celsius. The purpose is to condense and discharge a part of the moisture in the hydrogen chloride gas, thereby effectively reducing the water content of the gas before the hydrogen chloride gas enters the demister, so as to improve the dehydration effect on the hydrogen chloride gas.

[0017] Furthermore, in the present application document, the hydrogen chloride gas is dehydrated first and then cracked. When the dehydrated hydrogen chloride gas enters the cracking kettle for reaction, it is not easy to hydrolyze with high boilers, block the hydrogen chloride pipeline distributor and corrode the internal reflux condenser. After the hydrogen chloride gas enters the distributor, it is evenly distributed for reaction, improving the reaction efficiency. After sufficient reaction, the product quality is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic structural diagram of the dehydration device.

[0019] In the figure: 1. Dehydration device; 2. Hydrogen chloride gas; 10. Heat exchanger; 20. Demister; 21. Primary demister; 211. Wire mesh demisting filter element; 2111. First wire mesh demisting filter element; 2112. Second wire mesh demisting filter element; 22. Secondary demister; 221. Fiber filter element; 30. Cracking kettle; 40. Liquid storage tank; 50. Inlet; 60. Outlet; 70. Control valve. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] Next, in combination with the specific embodiments, the present application will be further described. It should be noted that on the premise of no conflict, the following described embodiments or technical features can be arbitrarily combined with each other to form new embodiments.

[0021] In the description of the present application, it should be noted that for the orientation terms, if there are terms such as "center", "horizontal", "vertical", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation and position relationship is based on the orientation or position relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific protection scope of the present application.

[0022] It should be noted that the terms "first", "second", etc. in the description and claims of this application are used to distinguish similar objects and do not necessarily describe a specific order or sequence.

[0023] The terms "comprising" and "having" and any variations thereof in the description and claims of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that comprises a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices.

[0024] In a preferred embodiment, referring to Figure 1 , this application provides a dehydration device 1 for hydrogen chloride gas 2, comprising: a heat exchanger 10, the heat exchanger 10 is externally connected to the introduction of un-dehydrated hydrogen chloride gas 2, and the heat exchanger 10 is used for deeply condensing the hydrogen chloride gas 2; a demister 20, the demister 20 is connected to the heat exchanger 10, and the demister 20 is used for demisting the condensed hydrogen chloride gas 2; a cracking kettle 30, the cracking kettle 30 is connected to the demister 20, and the cracking kettle 30 is used for cracking the demisted hydrogen chloride gas 2 to form a crude monomer.

[0025] Among them, the heat exchanger 10 is specifically a graphite condenser. Before the hydrogen chloride gas 2 enters the dehydration device 1 provided in this application, the desorbed hydrogen chloride gas 2 contains moisture and other impurities, and it is inevitable that liquid particles are suspended in the hydrogen chloride gas stream, which are generally formed through the following ways: liquid is formed into mist particles by mechanical force; the steam in the gas condenses to form mist particles; two or more gases undergo a chemical reaction to form mist particles at a certain temperature and pressure. Usually, the particle size of the mist particles formed by mechanical force is relatively large, while the particle size of the mist particles formed by condensation or chemical reaction is relatively small, such as submicron particles. The existence of mist particles will cause problems such as equipment corrosion, product impurity, blockage of the heat exchanger 10, catalyst failure, and damage to instruments and meters, and it will also cause environmental pollution when discharged into the atmosphere.

[0026] Therefore, this application document is provided with a graphite condenser before the hydrogen chloride gas 2 enters the demister 20 for deep condensation, and the temperature is controlled to about 10 degrees Celsius. The purpose is to condense and discharge a part of the moisture in the hydrogen chloride gas 2, thereby effectively reducing the water content of the gas before the hydrogen chloride gas 2 enters the demister 20, so as to improve the dehydration effect of the hydrogen chloride gas 2.

[0027] The gas condensed by the graphite condenser enters the demister 20 through a pipeline. Among them, the demister 20 includes: a primary demister 21, one end of the primary demister 21 is communicated with the heat exchanger 10; a secondary demister 22, one end of the secondary demister 22 is communicated with the primary demister 21, and the other end of the secondary demister 22 is communicated with the cracking kettle 30. Therefore, preferably, the hydrogen chloride gas 2 condensed by the graphite condenser preferably enters the interior of the primary demister 21 through the air inlet 50 of the primary demister 21 through a pipeline. Among them, the air inlet 50 of the primary demister 21 is arranged at the bottom of the primary demister 21, the air outlet 60 of the primary demister 21 is arranged at the top of the primary demister 21, the primary demister 21 is provided with a wire mesh demisting filter element 211, and the wire mesh demisting filter element 211 is arranged in the middle of the primary demister 21; among them, the hydrogen chloride gas 2 enters the primary demister 21 from the air inlet 50, and the wire mesh demisting filter element 211 is used to gather and intercept the liquid droplets in the hydrogen chloride gas 2, remove the mist and / or droplets entrained in the hydrogen chloride gas 2, or purify the hydrogen chloride gas 2 to reduce the impurities in the gas, and at the same time recover the removed droplets, and the formed droplets are a kind of precious material. The hydrogen chloride gas 2 after demisting by the wire mesh demisting filter element 211 is discharged from the air outlet 60 at the top of the primary demister 21 and enters the secondary demister 22.

[0028] It should be noted that the wire mesh demisting filter element 211 is generally preferably made of metal wires with a diameter of 0.1 mm to 0.28 mm or engineering plastics such as PP, PTFE, FEP, PVDF, etc., woven into a wire mesh in a special warp and weft manner, and then the woven wire mesh is pressed into a corrugation with a certain angle. The corrugated wire mesh is made into various specifications and sizes.

[0029] Among them, the wire mesh demisting filter element 211 has different forms for different fields. Therefore, the mechanism of action of the wire mesh demisting filter element 211 in this application document is as follows: The fine liquid droplets entrained in the hydrogen chloride gas 2 in the gas phase, when passing through the wire mesh of the wire mesh demisting filter element 211, the droplets touch the demisting wire mesh of the wire mesh demisting filter element 211, and then the droplets are adhered or adsorbed. As the hydrogen chloride gas 2 climbs, after repeatedly adsorbing droplets many times, the extremely small droplets agglomerate and coalesce into large droplets. Under the action of gravity, the droplets move downward along the intersections of the wires in the wire mesh formed by weaving, and at the same time continue to adsorb the droplets entrained in the hydrogen chloride gas 2. The converging and growing droplets flow to the bottom of the wire mesh demisting filter element 211 and fall down by the gravity of the droplets themselves. In fact, during the absorption process, since the inside of the entire wire mesh demisting filter element 211 is filled with adsorbed droplets, the adsorption capacity of a single metal or engineering plastic wire is enhanced. When working normally, the demisting rate of the demisting wire mesh is greatly improved, and extremely small droplets can be effectively adsorbed and removed. This wire mesh demisting filter element 211 has the characteristics of small pressure drop, large specific surface area, and high demisting efficiency. For droplets larger than 3μm, its demisting efficiency can reach more than 98%.

[0030] Further preferably, the secondary demister 22 is provided with a fiber filter element 221. The hydrogen chloride gas 2 dehydrated by the primary demister 21 enters the secondary demister 22, and the droplets in the hydrogen chloride gas 2 are coalesced through the fiber filter element 221 and deposited at the bottom of the secondary demister 22. Similarly, the secondary demister 22 is provided with an air inlet end and an air outlet end in the same way as the primary demister 21. The air inlet end of the secondary demister 22 is connected to the air outlet 60 of the primary demister 21 through a pipeline, and the air outlet end of the secondary demister 22 is connected to the cracking kettle 30 through a pipeline. It should be noted that control valves 70 are provided on each pipeline to control the flow of the hydrogen chloride gas 2. When the fiber filter element 221 is working, it mainly achieves the purpose of collecting the fog particles in the hydrogen chloride gas 2 through mechanisms such as inertial collision, direct interception, Brownian motion, and electrostatic action in the fiber bed layer of the fiber filter element 221.

[0031] Specifically, the demisting process of the fiber filter element 221 in the secondary demister 22 is as follows: For example, for fog particles with an inertial collision diameter greater than 3μm, the fog particles with this diameter have a large inertial force, so the momentum causes the fog particles with this diameter to break away from the air flow streamline and directly hit the fiber filter element 221 and be captured. Further, for fog particles with a direct interception diameter between 1 and 3μm, the fog particles with this diameter move along the air flow streamline. When it is quite close to the fiber filter element 221, the fog particles with this diameter will be captured at this time. Moreover, for example, when the fog particles with a diameter of 1μm are in the fiber filter element 221 with a fiber spacing less than 0.5μm, they will be captured.

[0032] Furthermore, Brownian motion causes random motion due to the collisions between very fine particles and gas molecules. Therefore, the direction of this motion can be either along the gas flow direction, or opposite to the gas flow direction, or perpendicular to the gas flow direction. Brownian motion increases as the fog particles decrease. The Brownian motion of fog particles with a diameter of 0.1 μm is 5 times that of fog particles with a diameter of 1 μm. Thus, the chance of being trapped by the fiber filter element 221 is greatly increased, thereby achieving the purpose of removing water and other impurities from the hydrogen chloride gas 2.

[0033] Further preferably, the dehydration device 1 further includes a liquid storage tank 40. The bottom of the primary demister 21 is connected to the bottom of the secondary demister 22 to communicate with the liquid storage tank 40. Among them, the droplets in the hydrogen chloride gas 2 aggregated by the primary demister 21 and the secondary demister 22 are introduced into the liquid storage tank 40 for storage. The liquid storage tank 40 is specifically a deacidification tank in this application document.

[0034] Further preferably, a plurality of wire mesh demisting filter elements 211 are arranged inside the primary demister 21.

[0035] Preferably, two wire mesh demisting filter elements 211 are arranged in the primary demister 21 in this application document. The wire mesh demisting filter element 211 includes: a first wire mesh demisting filter element 2111 and a second wire mesh demisting filter element 2112. The first wire mesh demisting filter element 2111 and the second wire mesh demisting filter element 2112 are arranged at intervals along the climbing direction of the hydrogen chloride gas 2. Therefore, when the hydrogen chloride gas 2 rises in the primary demister 21, it first passes through the demisting of the first wire mesh demisting filter element 2111, and then through the demisting of the second wire mesh demisting filter element 2112 to effectively ensure the demisting effect.

[0036] Specifically, in an actual operation step, first introduce the water-containing hydrogen chloride gas 2 desorbed into a graphite condenser, control the temperature within 10 degrees Celsius, set the pressure to 0.2 MPa, and cool under these conditions. After discharging a part of the water, all the cooled hydrogen chloride gas 2 and the remaining water molecules it carries enter the primary demister 21 through a pipeline.

[0037] After the hydrogen chloride gas 2 enters the primary demister 21, the droplets entrained by the hydrogen chloride gas 2 are aggregated and intercepted by the wire mesh demisting filter element 211 and enriched at the bottom of the primary demister 21, and are discharged to the deacidification tank through the externally connected pipeline at the bottom. The tail gas of the dehydrated hydrogen chloride gas 2 enters the secondary demister 22 through a pipeline.

[0038] After the hydrogen chloride gas 2 enters the secondary demister 22, demisting is carried out through the fiber filter element 221. Relying on the Brownian motion of the droplets in the hydrogen chloride gas 2 to cause collisions with the modified fibers, the purpose of capturing the droplets in the gas phase is achieved. The air flow passes through the fiber filter element 221 horizontally from the outside to the inside. The modified fibers in the fiber filter element 221 have the function of coalescing water. Under the action of gravity, the droplets flow down along the inner wall until they are discharged to the acid removal tank at the bottom of the equipment. At the same time, the hydrogen chloride gas 2 passes through the fiber filter element 221 and is discharged to the cracking kettle 30 through the pipeline from the inside to the outside.

[0039] After the hydrogen chloride gas 2 is dehydrated by the secondary demister 22, it enters the cracking kettle 30. Through the regulation of the regulating valve, it enters the kettle and reacts with the high-boiling substances in the kettle under the catalytic action of the catalyst tri-n-butylamine at 145-155 °C to crack and generate crude monomers. Therefore, in this application document, the hydrogen chloride gas 2 is first dehydrated and then cracked. When the dehydrated hydrogen chloride gas 2 enters the cracking kettle 30 for reaction, it is not easy to hydrolyze with the high-boiling substances, block the hydrogen chloride pipeline distributor and corrode the internal reflux condenser. After the hydrogen chloride gas 2 enters the distributor, it is evenly distributed for reaction, improving the reaction efficiency. After sufficient reaction, the product quality is improved.

[0040] The above describes the basic principle, main features and advantages of this application. Those skilled in the art should understand that this application is not limited by the above embodiments. What is described in the above embodiments and the specification is only the principle of this application. Without departing from the spirit and scope of this application, this application will have various changes and improvements, and these changes and improvements all fall within the scope of this application claimed. The scope of protection required by this application is defined by the appended claims and their equivalents.

Claims

1. A dehydration device for hydrogen chloride gas, characterized in that, Comprising: A heat exchanger, which is externally connected to the introduction of the un-dehydrated hydrogen chloride gas, and is used for deeply condensing the hydrogen chloride gas; A demister, which is communicated with the heat exchanger, and is used for removing mist from the condensed hydrogen chloride gas; A cracking kettle, which is communicated with the demister, and is used for cracking the hydrogen chloride gas after mist removal to form crude monomers.

2. The dehydration device for hydrogen chloride gas according to claim 1, characterized in that, The demister includes: A primary demister, one end of which is communicated with the heat exchanger; A secondary demister, one end of which is communicated with the primary demister, and the other end of which is communicated with the cracking kettle.

3. The dehydration device for hydrogen chloride gas according to claim 2, characterized in that The primary demister is provided with a wire mesh demisting filter element, which is used for aggregating and intercepting the liquid droplets in the hydrogen chloride gas to enrich the liquid droplets to the bottom of the primary demister.

4. The dehydration device for hydrogen chloride gas according to claim 2, characterized in that The secondary demister is provided with a fiber filter element. The hydrogen chloride gas dehydrated by the primary demister enters the secondary demister, and the liquid droplets in the hydrogen chloride gas are coalesced through the fiber filter element to be deposited at the bottom of the secondary demister.

5. The dehydration device for hydrogen chloride gas according to claim 2, characterized in that, It further includes: A liquid storage tank, the bottom of the primary demister is communicated with the bottom of the secondary demister to the liquid storage tank; Wherein, the liquid droplets in the hydrogen chloride gas aggregated by the primary demister and the secondary demister are introduced into the liquid storage tank for storage.

6. The dehydration device for hydrogen chloride gas according to claim 3, characterized in that A plurality of the wire mesh demisting filter elements are arranged in the primary demister.

7. The dehydration device for hydrogen chloride gas according to claim 6, characterized in that, The wire mesh demisting filter element includes: A first wire mesh demisting filter element and a second wire mesh demisting filter element, which are arranged at intervals along the climbing direction of the hydrogen chloride gas.

8. The dehydration device for hydrogen chloride gas according to any one of claims 1-7, characterized in that The heat exchanger is a graphite heat exchanger.

9. The dehydration device for hydrogen chloride gas according to claim 3, characterized in that The air inlet of the primary demister is arranged at the bottom of the primary demister, the air outlet of the primary demister is arranged at the top of the primary demister, and the wire mesh demisting filter element is arranged in the middle of the primary demister; Wherein, the hydrogen chloride gas enters the primary demister from the air inlet, climbs through the wire mesh demisting filter element, and then enters the secondary demister from the air outlet.

10. The dehydration device for hydrogen chloride gas according to claim 3, characterized in that The wire mesh demisting filter element is woven in a warp and weft manner, and the wire mesh demisting filter element is provided with corrugations at a certain angle.

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