Absorption tower for hydrogen cyanide production

Abstract

The utility model relates to the technical field of chemical production equipment, and discloses an absorption tower for hydrogen cyanide production, which comprises a tower body, a liquid conveying pipe and a gas inlet pipe, the top of the tower body is provided with an exhaust port, the bottom of the tower body is provided with a liquid collecting tank, and the liquid collecting tank is used for collecting an absorbed hydrogen chloride aqueous solution; the liquid conveying pipe is located at the end, close to the bottom, of the side wall of the tower body and used for conveying low-temperature water into the tower body. The gas inlet pipe is located at the end, close to the bottom, of the side wall of the tower body, the end, located in the tower body, of the gas inlet pipe extends towards the bottom of the liquid collecting pool, and the gas inlet pipe is used for conveying gas containing hydrogen chloride into the tower body; a collecting disc is arranged in the middle of the tower body, the collecting disc is horizontally arranged in the tower body, and a plurality of small holes are formed in the collecting disc. The utility model has the beneficial effect of high absorption efficiency.

Description

Technical Field

[0001] The utility model relates to the technical field of chemical production equipment, in particular to an absorption tower used for hydrogen cyanide production. Background Art

[0002] Hydrogen cyanide (HCN) is an inorganic compound that is in liquid state in the standard state. Hydrogen cyanide is widely used in the electroplating industry (copper plating, gold plating, silver plating), mining industry (extraction of gold and silver) and the manufacturing of various resin monomers (such as acrylic resin, methacrylic resin, etc.) in the industrial field. It is an important chemical raw material. Among them, the main synthesis methods of hydrogen cyanide include: acrylonitrile by-product method, natural gas ammoxidation method, light oil cracking method, methanol ammoxidation method, formamide dehydration method, etc. The methanol ammoxidation method mainly uses methanol, ammonia and air as raw materials. It has the advantages of a wide range of material sources and convenient transportation and is widely used. Among them, when synthesizing hydrogen cyanide through the methanol ammoxidation method, it is usually necessary to absorb hydrogen cyanide through water, and then produce liquid hydrogen cyanide through distillation.

[0003] For example, the patent document with publication number CN105366692B discloses a process and system for preparing high-purity liquid hydrogen cyanide, which obtains liquid hydrogen cyanide with low water content by absorbing low-temperature water in an absorption tower and operating a three-stage distillation tower and a gas-liquid separator. This technical solution uses low-temperature water absorption to improve the absorption efficiency of HCN gas, reduce the load on subsequent tail gas treatment facilities, and alleviate environmental pressure.

[0004] Although the above technical scheme can realize the efficient and smooth production of hydrogen cyanide, when hydrogen cyanide is absorbed by low-temperature water, the low-temperature water and hydrogen cyanide in the gas are absorbed by spraying to obtain an aqueous hydrogen cyanide solution. Since the coverage of the low-temperature water in the dripping process is limited, there are gaps between the dripping low-temperature water, resulting in the hydrogen cyanide in the gas cannot be fully absorbed by the low-temperature water, so that the gas after absorption still contains a large amount of hydrogen cyanide, resulting in reduced utilization of raw materials in the production process, resulting in waste of resources and increased production cost of hydrogen cyanide. Utility Model Content

[0005] The utility model aims to provide an absorption tower for hydrogen cyanide production, so as to solve the technical problem in the prior art that hydrogen cyanide in gas cannot be fully absorbed by low-temperature water, resulting in reduced utilization rate of raw materials in the production process.

[0006] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: an absorption tower for hydrogen cyanide production, comprising a tower body, a liquid infusion pipe and an air inlet pipe, wherein the top of the tower body is provided with an exhaust port, and the bottom of the tower body is provided with a liquid collecting tank, and the liquid collecting tank is used to collect the absorbed hydrogen chloride aqueous solution; the liquid infusion pipe is located at one end of the side wall of the tower body close to the bottom, and the liquid infusion pipe is used to transport low-temperature water into the tower body; the air inlet pipe is located at one end of the side wall of the tower body close to the bottom, and the end of the air inlet pipe located in the tower body extends toward the bottom of the liquid collecting tank, and the air inlet pipe is used to transport gas containing hydrogen chloride into the tower body; a collecting tray is provided in the middle of the tower body, and the collecting tray is horizontally arranged in the tower body, and a plurality of small holes are opened on the collecting tray.

[0007] The principle and advantage of this scheme are: when absorbing hydrogen cyanide, the gas containing hydrogen cyanide is transported into the tower body through the air inlet pipe, and the gas containing hydrogen cyanide is sprayed out from the liquid collecting pool in the tower body, and the gas containing hydrogen cyanide moves upward through the hydrogen cyanide aqueous solution in the liquid collecting pool, and at the same time, the liquid infusion pipe sprays low-temperature water from the top of the tower body, and the low-temperature water absorbs the hydrogen cyanide in the gas in the absorption tower and falls into the liquid collecting pool to form a hydrogen cyanide aqueous solution, and the remaining gas after being absorbed by the low-temperature water is transported to the treatment device through the exhaust port for treatment.

[0008] In this scheme, the low-temperature water is sprayed twice through the infusion tube and the collection plate to distribute the low-temperature water so that the low-temperature water can cover the absorption chamber more comprehensively. At the same time, a collection plate is set to block and collect the low-temperature water during its descent to prevent the low-temperature water from accelerating under the action of gravity acceleration. This scheme collects the low-temperature water through the collection plate and then discharges it downward, which reduces the speed of the low-temperature water moving downward, increases the contact time between the low-temperature water and the gas, and improves the absorption efficiency of the low-temperature water.

[0009] Furthermore, by discharging the gas containing hydrogen cyanide upward from the liquid collecting pool, the hydrogen cyanide aqueous solution in the liquid collecting pool can preliminarily absorb the hydrogen cyanide in the gas when the gas containing hydrogen cyanide passes through the liquid collecting pool, thereby reducing the hydrogen cyanide content in the gas. At the same time, the gas containing hydrogen cyanide is cooled under the action of the liquid in the liquid collecting pool, thereby ensuring that the temperature of the gas containing hydrogen cyanide can be maintained within the optimal absorption range, thereby further improving the absorption efficiency of hydrogen cyanide by low-temperature water.

[0010] Preferably, as an improvement, the liquid infusion pipe runs through the side wall of the tower body, one end of the liquid infusion pipe located in the tower body is connected to the spray pipe network, and the spray pipe network is provided with a plurality of spray nozzles, and the spray nozzles are evenly distributed along the plane where the cross section of the tower body is located. The low-temperature water transported to the tower body can be evenly and finely sprayed under the action of the spray pipe network, thereby improving the coverage rate of the low-temperature water in the tower body.

[0011] Preferably, as an improvement, the air inlet pipe penetrates the side wall of the tower body, and the position where the air inlet pipe penetrates the tower body is higher than the top of the liquid collecting tank, so as to ensure that when the air inlet pipe transports gas into the tower body, the hydrogen cyanide solution in the liquid collecting tank can be prevented from flowing back through the liquid infusion pipe.

[0012] Preferably, as an improvement, one end of the air inlet pipe located in the tower body is connected to an air inlet network, the air inlet network is laid at the bottom of the liquid collecting pool, a plurality of spray guns are arranged on the air inlet network, the gas outlets of the spray guns face the top of the tower body, and the height of the spray guns is lower than the liquid level of the liquid collecting pool. While ensuring the uniformity of the distribution of the gas containing hydrogen cyanide in the tower body, the spray guns can spray gas from below the liquid level of the hydrogen cyanide solution in the liquid collecting pool, ensuring that the sprayed gas can contact the hydrogen cyanide aqueous solution in the liquid collecting pool.

[0013] Preferably, as an improvement, the collecting tray is provided with packing layers on both sides along the height direction of the tower body, and the packing layers are spaced apart from the spray pipe network, the collecting tray and the liquid collecting tank. By providing the packing layers in the absorption chamber, the gas and the low-temperature water pass through the middle of the packing layers when moving, so that the gas and the low-temperature water can be in closer contact under the action of the packing, thereby improving the absorption effect of the low-temperature water on hydrogen cyanide.

[0014] Preferably, as an improvement, a demister is installed at one end of the tower body near the exhaust port, so that the moisture in the gas discharged from the exhaust port can be filtered under the action of the demister, thereby preventing the water vapor that absorbs hydrogen cyanide from being discharged through the exhaust port. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the absorption tower structure in the embodiment of the utility model. DETAILED DESCRIPTION

[0016] The following is further described in detail through specific implementation methods:

[0017] The figure marks in the drawings of the specification include: tower body 1, absorption chamber 101, liquid collecting tank 102, output pipe 103, exhaust port 104, liquid delivery pipe 2, spray pipe network 201, spray nozzle 202, air inlet pipe 3, air inlet pipe network 301, spray gun 302, collection tray 4, packing layer 5, demister 6.

[0018] As attached Figure 1 As shown, an absorption tower for hydrogen cyanide production includes a tower body 1, on which a liquid infusion pipe 2 and an air inlet pipe 3 are provided. The liquid infusion pipe 2 is used to transport low-temperature water into the tower body 1, and the air inlet pipe 3 is used to transport gas containing hydrogen cyanide into the tower body 1. Cooling water is used to absorb the gas transported by the air inlet pipe 3 to form a hydrogen cyanide aqueous solution and collect it at the bottom of the tower body 1.

[0019] An absorption chamber 101 is provided inside the tower body 1, and the central axis of the absorption chamber 101 extends upward in the height direction, wherein the specific structure of the tower body 1 and the absorption chamber 101 is prior art and will not be described in detail here. The liquid infusion pipe 2 penetrates through one end of the side wall of the absorption chamber 101 close to the top of the tower body 1, one end of the liquid infusion pipe 2 is connected to the low-temperature water delivery pipe, and the other end extends into the absorption chamber 101, and the end of the liquid infusion pipe 2 located in the absorption chamber 101 is connected to a spray pipe network 201 through a thread, and a plurality of spray nozzles 202 are connected to the spray pipe network 201, and the spray nozzles 202 are evenly distributed along the plane where the cross section of the absorption chamber 101 is located, and the spray nozzles 202 are used to evenly spray low-temperature water into the absorption chamber 101.

[0020] A collecting tray 4 is provided in the middle of the extending direction of the absorption chamber 101. The collecting tray 4 is arranged horizontally in the absorption chamber 101. The circumference of the collecting tray 4 is fixedly connected to the side wall of the absorption chamber 101 by bolts. A plurality of small holes are provided on the collecting tray 4, and the plurality of small holes are evenly distributed on the collecting tray 4. The small holes run through both sides of the collecting tray 4. The collecting tray 4 is used to collect the low-temperature water sprayed by the spray pipe network 201 and spray and distribute it again through the small holes. The low-temperature water sprayed downward can be sprayed with secondary distribution under the action of the collecting tray 4, so as to avoid the low-temperature water from always moving downward in a straight line after the spray pipe network 201, resulting in gaps between adjacent moving paths, and reducing the contact area between the low-temperature water and the gas. At the same time, the speed of the low-temperature water is adjusted by the collecting tray 4 to ensure the moving time of the low-temperature water in the absorption chamber 101, increase the contact time between the low-temperature water and the gas, and improve the absorption effect of the low-temperature water on hydrogen cyanide in the gas.

[0021] At the bottom of the absorption chamber 101 is a liquid collecting tank 102, which is used to collect low-temperature water after absorbing hydrogen cyanide. An output port is opened at the top of the liquid collecting tank 102, and the output port runs through the side wall of the tower body 1. The output port is connected to the output pipe 103, and the output pipe 103 is used to output the hydrogen cyanide aqueous solution in the liquid collecting tank 102 to the next processing step for processing.

[0022] The air inlet pipe 3 is located at one end of the side wall of the tower body 1 near the bottom, and the air inlet pipe 3 passes through the side wall of the tower body 1. Specifically, the position where the air inlet pipe 3 passes through the tower body 1 is higher than the position of the output port; one end of the air inlet pipe 3 is connected to the gas transmission pipe, and the other end extends to the bottom of the liquid collecting pool 102 inside the tower body 1, wherein the end of the air inlet pipe 3 located in the absorption chamber 101 is connected to the air inlet pipe network 301 through a thread, and the air inlet pipe network 301 is laid at the bottom of the liquid collecting pool 102, and a plurality of spray guns 302 are connected to the air inlet pipe network 301 through a thread, and the air outlet of the spray gun 302 faces the top of the absorption chamber 101, and the height of the spray gun 302 is lower than the output port, and the spray gun 302 is used to spray the gas in the air inlet pipe 3 into the liquid collecting pool 102. The gas containing hydrogen cyanide inputted by the air inlet pipe 3 can be cooled in the aqueous hydrogen cyanide solution formed after being absorbed by low-temperature water, so that the temperature of the gas containing hydrogen cyanide can be reduced to the optimal absorption temperature. At the same time, when the gas containing hydrogen cyanide passes through the aqueous hydrogen cyanide solution, the aqueous hydrogen cyanide solution can absorb the hydrogen cyanide in the gas, thereby reducing the concentration of hydrogen cyanide in the gas.

[0023] A packing layer 5 is provided on both sides of the collecting tray 4 along the height direction of the absorption chamber 101. The packing layer 5 is filled in the absorption chamber 101, and the packing layer 5 is spaced apart from the spray pipe network 201, the collecting tray 4 and the liquid collecting tank 102. The packing layer 5 is filled with packing, and gaps are provided between the packings for gas and low-temperature water to pass through. The specific structure and packing material of the packing layer 5 are prior art and will not be described in detail here. By providing the packing layer 5 in the absorption chamber 101, the gas and low-temperature water pass through the middle of the packing layer 5 when moving, so that the gas and low-temperature water can be in closer contact under the action of the packing, thereby improving the absorption effect of low-temperature water on hydrogen cyanide.

[0024] An exhaust port 104 is provided at the top of the tower body 1. The exhaust port 104 runs through the tower body 1 and communicates with the absorption chamber 101. The exhaust port 104 is located at one end of the outer wall of the tower body 1 and is connected to an exhaust pipe, which is used to transport the absorbed gas in the tower body 1 to the exhaust gas treatment device for treatment. A demister 6 is installed at one end of the absorption chamber 101 close to the exhaust port 104. The demister 6 is fixedly connected to the side wall of the absorption chamber 101 in the circumferential direction. The demister 6 is used to filter the water vapor in the exhaust gas. The specific structure of the demister 6 is prior art and will not be described in detail here.

[0025] The specific implementation process is as follows:

[0026] When absorbing hydrogen cyanide, the gas containing hydrogen cyanide is transported to the air intake network 301 in the tower body 1 through the air intake pipe 3. The air intake network 301 sprays the gas containing hydrogen cyanide from the liquid collecting pool 102 in the tower body 1. The gas containing hydrogen cyanide moves upward through the aqueous hydrogen cyanide solution in the liquid collecting pool 102. At the same time, the infusion pipe 2 transports low-temperature water to the spray network 201 in the tower body 1. The spray network 201 sprays the low-temperature water evenly into the absorption chamber 101. The low-temperature water absorbs the hydrogen cyanide in the gas in the absorption chamber 101 and drops into the liquid collecting pool 102 to form an aqueous hydrogen cyanide solution. The remaining gas absorbed by the low-temperature water is transported to the treatment device through the exhaust port 104 for treatment.

[0027] Compared with the prior art, in this solution, the spraying of low-temperature water is distributed twice by the spraying pipe network 201 and the collecting plate 4, so that the low-temperature water can cover the absorption chamber 101 more comprehensively. At the same time, the collecting plate 4 is set to block and collect the low-temperature water during its descent, so as to avoid the low-temperature water from accelerating under the action of gravity acceleration and reduce the contact time with the gas. In this solution, the low-temperature water is collected by the collecting plate 4 and then discharged downward, so that the speed of the low-temperature water moving downward is reduced, the contact time between the low-temperature water and the gas is increased, and the absorption efficiency of the low-temperature water is improved. In addition, by discharging the gas containing hydrogen cyanide upward from the collecting tank 102, when the gas containing hydrogen cyanide passes through the collecting tank 102, the hydrogen cyanide aqueous solution in the collecting tank 102 can initially absorb the hydrogen cyanide in the gas, reduce the hydrogen cyanide content in the gas, and cool the gas containing hydrogen cyanide under the action of the liquid in the collecting tank 102, so as to ensure that the temperature of the gas containing hydrogen cyanide can be kept within the optimal absorption range, and further improve the absorption efficiency of hydrogen cyanide by low-temperature water.

[0028] The above are only embodiments of the present invention, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the technical solution of the present invention, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. An absorption tower for hydrogen cyanide production, characterized in that: It includes a tower body, a liquid infusion pipe and an air inlet pipe. The top of the tower body is provided with an exhaust port, and the bottom of the tower body is provided with a liquid collecting tank, which is used to collect the absorbed hydrogen chloride aqueous solution; the liquid infusion pipe is located at one end of the side wall of the tower body close to the bottom, and the liquid infusion pipe is used to transport low-temperature water into the tower body; the air inlet pipe is located at one end of the side wall of the tower body close to the bottom, and one end of the air inlet pipe located in the tower body extends toward the bottom of the liquid collecting tank, and the air inlet pipe is used to transport gas containing hydrogen chloride into the tower body; a collecting tray is provided in the middle of the tower body, and the collecting tray is horizontally arranged in the tower body, and a plurality of small holes are opened on the collecting tray.

2. An absorption tower for hydrogen cyanide production according to claim 1, characterized in that: The liquid infusion pipe runs through the side wall of the tower body, and one end of the liquid infusion pipe located in the tower body is connected to a spray pipe network. The spray pipe network is provided with a plurality of spray nozzles, and the spray nozzles are evenly distributed along the plane where the cross section of the tower body is located.

3. An absorption tower for hydrogen cyanide production according to claim 1, characterized in that: The air inlet pipe penetrates through the side wall of the tower body, and the position where the air inlet pipe penetrates through the tower body is higher than the top of the liquid collecting tank.

4. An absorption tower for hydrogen cyanide production according to claim 3, characterized in that: One end of the air inlet pipe located in the tower body is connected to the air inlet network, and the air inlet network is laid at the bottom of the liquid collecting tank. A plurality of spray guns are arranged on the air inlet network, and the air outlet of the spray gun faces the top of the tower body. The height of the spray gun is lower than the liquid level of the liquid collecting tank.

5. An absorption tower for hydrogen cyanide production according to claim 2, characterized in that: The collecting tray is provided with packing layers on both sides along the height direction of the tower body, and the packing layers are spaced apart from the spray pipe network, the collecting tray and the liquid collecting pool.

6. The absorption tower for hydrogen cyanide production according to claim 1, characterized in that: A demister is installed in one end of the tower body close to the exhaust port.

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