Waste gas absorption system

Abstract

The utility model discloses a waste gas absorption system which comprises a first-stage absorption tower, a second-stage absorption tower, a third-stage absorption tower and an air inducing device, air outlets of the first-stage absorption tower and the second-stage absorption tower are respectively communicated with an air inlet of the next-stage absorption tower through pipelines, and an air outlet of the third-stage absorption tower is communicated with the air inducing device through a pipeline. Each of the first-stage absorption tower, the second-stage absorption tower and the third-stage absorption tower independently comprises a spray head, a filling area and a collecting area which are communicated with one another. According to the waste gas absorption system, multiple stages such as three-stage absorption towers are connected in series, so that the waste gas absorption efficiency is improved, the water unit consumption is reduced, and the waste gas emission reaches the environment-friendly emission standard. The washing liquid is easy to form a'water film 'during operation of the absorption tower, so that the contact area of water and gas phases is increased, and the absorption effect on waste gas is improved. And the washing liquid absorbing the impurities and heat can be recycled or conveyed to a production line of a main product to be used as a raw material, so that the production cost is further saved.

Description

Technical Field

[0001] The utility model belongs to the technical field of separation and purification of chemical products, and in particular relates to a waste gas absorption system. Background Art

[0002] 1,5-Pentanediamine (Diaminopentane; hereinafter referred to as cadaverine), also known as cadaverine, has a wide range of applications in agriculture, medicine and industry. In agriculture, exogenous application of pentamethylenediamine can improve fruit setting and promote fruit ripening; in medicine, pentamethylenediamine can be used as an effective drug for treating dysentery; in industry, pentamethylenediamine prepared by biological fermentation can replace diamines from petrochemical products and undergo polymerization reactions to generate various polymers with different properties, thereby avoiding the high cost of petrochemical products and the adverse effects of production on the environment. Polymers can be widely used in aerospace, automotive parts, mechanical parts, electronic appliances, packaging materials and other fields.

[0003] Industrially, the preparation process of 1,5-pentanediamine generally includes: obtaining a 1,5-pentanediamine salt solution through fermentation or enzyme conversion process. Then the salt solution is subjected to a series of extraction and purification treatments such as adding alkali, extraction, and evaporation to obtain a 1,5-pentanediamine aqueous solution, and then 1,5-pentanediamine is obtained through distillation. In the process of extracting and refining pentamethylenediamine, the waste gas generated needs to be further absorbed and treated. The waste gas generated in the production process of pentamethylenediamine generally consists of water, ammonia, pentamethylenediamine and pentamethylenediamine salts, and the waste gas is alkaline.

[0004] Since the composition of waste gas is complex and its components have different characteristics, it is difficult to purify it. Currently, the commonly used treatment methods are: condensation method, absorption method, combustion method, catalytic method, adsorption method, etc. The absorption method is a single-stage absorption process of immersion absorption of waste gas. The waste gas is transported to the water tank through a pipeline. The air duct is evenly distributed below the liquid level. The distance between the liquid surface and the air duct is short. The waste gas overflows from the holes opened on the air duct. The impurities in the waste gas are absorbed and discharged through the mixed contact of gas and water. The absorption method mainly has the following problems: 1) Since a certain wind pressure is required for the waste gas to enter the immersed absorption tank, and the air duct is connected to the vent pipe of each storage tank, it is easy to cause the pressure in each storage tank to be positive, which brings a certain leakage risk to the production process; 2) In the existing absorption process, the contact between the waste gas and water is in the form of bubbles and static water, with a small contact area, short contact time, and low adsorption efficiency. A small amount of alkaline materials are also entrained in the waste gas after adsorption treatment; 3) Due to the low waste gas absorption efficiency, the absorption efficiency is often improved by increasing the amount of water replenishment and reducing the material concentration in the aqueous solution, which leads to a reduction in the waste gas material content in the system, an increase in the water consumption per unit, and an increase in the steam evaporation cost. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a waste gas absorption system, which improves the absorption efficiency of the system through multi-stage absorption tower washing and adsorption, and can reuse the washing water of the absorption tower to reduce production costs. The waste gas can meet environmental protection requirements after treatment.

[0006] The waste gas absorption system includes: a primary absorption tower, a secondary absorption tower, a tertiary absorption tower and a draft device. The gas outlets of the primary and secondary absorption towers are connected to the gas inlet of the next absorption tower through pipelines, and the gas outlet of the tertiary absorption tower is connected to the draft device through a pipeline. The primary, secondary and tertiary absorption towers each independently include a connected nozzle, a filling area and a collection area.

[0007] In one embodiment, the number of absorption towers in the exhaust gas absorption system is three or more, for example, greater than three, for example, 4, 5, 6, 8, etc.

[0008] In one embodiment, the exhaust gas absorption system includes four or more absorption towers.

[0009] In one embodiment, the exhaust gas absorption system has five absorption towers, that is, the system further includes a four-stage absorption tower and a five-stage absorption tower.

[0010] In one embodiment, the filler zone is located between the showerhead and the collection zone.

[0011] In one embodiment, the gas outlets of the primary absorption tower, the secondary absorption tower, and the tertiary absorption tower are located at the tops of the towers.

[0012] In one embodiment, the air inlet of the primary absorption tower, the secondary absorption tower, and the tertiary absorption tower is located at the lower part or the bottom of the absorption tower.

[0013] The waste gas enters the recovery system through the air inlet of the primary absorption tower.

[0014] In one embodiment, the collection area is located at the lower part of the absorption tower. The packing area is located at the upper part and / or the middle part of the absorption tower. The collection area is used to collect the washing liquid. The collection area is connected to a pump and a pipeline to pump the liquid in the collection area to a pipeline or a storage tank outside the absorption tower.

[0015] In one embodiment, the collection area is equipped with a liquid storage tank.

[0016] In one embodiment, the spray head is connected to an external washing liquid pipeline or a washing liquid storage tank.

[0017] In one embodiment, the number of the nozzles is one, two, three or more than three.

[0018] In one embodiment, the washing liquids of the primary absorption tower, the secondary absorption tower and the tertiary absorption tower are each independently selected from water or an acid solution.

[0019] In one embodiment, the acid solution is selected from a sulfuric acid solution.

[0020] In one embodiment, the washing liquid is applied in a specific manner. The washing liquid is transported from the collection area of ​​any absorption tower to the nozzle of any one or more absorption towers through a pipeline for application.

[0021] In one embodiment, the washing liquid in the collection area of ​​any absorption tower is transported to the nozzles of the primary absorption tower, the secondary absorption tower and / or the tertiary absorption tower for application.

[0022] In one embodiment, the washing liquids of the primary absorption tower, the secondary absorption tower, and the tertiary absorption tower are mutually applied. For example, the washing liquid of the collection area of ​​the secondary absorption tower is applied to any one, two, or three of the primary absorption tower, the secondary absorption tower, and the tertiary absorption tower.

[0023] In one embodiment, the washing liquid in the collection area of ​​the secondary absorption tower is transported to the primary absorption tower through a pipeline, and the washing liquid in the collection area of ​​the tertiary absorption tower is transported to the secondary absorption tower through a pipeline for application.

[0024] In one embodiment, the applied washing liquid is transported from the collection area of ​​the absorption tower to the production workshop through a pipeline for use as a raw material. Preferably, the production workshop is a main product production workshop, and the main product is pentamethylenediamine.

[0025] In one embodiment, the packing zone includes a support plate and a packing layer.

[0026] In one embodiment, the support plate has holes on its surface, and the hole diameter is smaller than the filler diameter.

[0027] In one embodiment, the number of the support plate and the packing layer is one, two, three or more than three.

[0028] In one embodiment, the distance between any adjacent support plates is 3-12 m.

[0029] In one embodiment, the packing layer is formed by uniformly piling the packing on the surface of the support plate. The height of the packing layer is 0.5 to 2.5 m.

[0030] In one embodiment, the particle size of the filler is 1 to 10 cm.

[0031] In one embodiment, the filler is, for example, a column with holes.

[0032] In one embodiment, the air inducing device is, for example, a fan.

[0033] In one embodiment, a foam catcher is installed between the gas outlet and the nozzle in the primary absorption tower, the secondary absorption tower and / or the tertiary absorption tower.

[0034] In one embodiment, the foam trap is a conventional device in the art. The structure of the foam trap generally includes a wire mesh and a cotton cloth arranged on the surface of the wire mesh. The wire mesh is a stainless steel wire mesh or a polyvinyl chloride corrugated mesh. The surface and interior of the cotton cloth have a pore structure that allows gas and liquid to pass through.

[0035] The system does not specifically limit the composition of the waste gas. Preferably, the system is particularly suitable for treating waste gas generated during the production of pentamethylenediamine, which generally includes at least two components of water, ammonia, pentamethylenediamine and a salt of pentamethylenediamine. The waste gas is alkaline.

[0036] The utility model adopts a multi-stage, for example, three-stage absorption tower connected in series, which improves the exhaust gas absorption efficiency and reduces the unit water consumption. At the same time, the exhaust gas emission meets the environmental protection emission standard.

[0037] When the absorption tower used in the utility model is in operation, the washing liquid easily forms a "water film", thereby improving the absorption effect of the exhaust gas. Compared with the immersed absorption water tank in the prior art, the contact area between the water and gas phases is increased.

[0038] In the system of the utility model, the washing liquid which has absorbed impurities and heat can be recycled or transported to the production line of the main product for use as raw material, thereby improving production efficiency, reducing water consumption and saving production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic structural diagram of the waste gas absorption system of the utility model.

[0040] Figure 2 It is a structural schematic diagram of the primary absorption tower of the utility model.

[0041] Figure numerals: 1-primary absorption tower, 2-secondary absorption tower, 3-tertiary absorption tower, 4-draft induced device, 11-air inlet, 12-air outlet, 13-nozzle, 14-filling area, 141-support plate, 142-filling layer, 15-collecting area, 16-foam catcher. DETAILED DESCRIPTION

[0042] The following will further describe the technical solution of the utility model in detail with reference to the accompanying drawings and specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the utility model, and should not be interpreted as limiting the scope of protection of the utility model. All technologies implemented based on the above content of the utility model are included in the scope of protection intended by the utility model.

[0043] It should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “inside” and “outside” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limitations on the present invention.

[0044] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0046] like Figure 1 As shown, an embodiment of the utility model discloses a waste gas absorption system, comprising a primary absorption tower 1, a secondary absorption tower 2, a tertiary absorption tower 3 and a draft device 4, the gas outlets of the primary absorption tower 1 and the secondary absorption tower 2 are respectively connected to the gas inlet of the next absorption tower through pipelines, the gas outlet of the tertiary absorption tower 3 is connected to the draft device 4 through a pipeline, and the primary, secondary and tertiary absorption towers each independently include a connected nozzle, a filling area and a collection area.

[0047] The nozzle is connected to an external cleaning liquid storage tank through a pipeline.

[0048] In one embodiment, the washing liquid of the primary absorption tower 1 and the secondary absorption tower 2 is water, and the washing liquid of the tertiary absorption tower 3 is sulfuric acid solution.

[0049] In another embodiment, the washing liquids of the primary absorption tower 1, the secondary absorption tower 2 and the tertiary absorption tower are all water.

[0050] In another embodiment, the washing liquid of the primary absorption tower 1 and the secondary absorption tower 2 is water, and the washing liquid of the tertiary absorption tower 3 is determined to be water or sulfuric acid solution by detecting the concentration value of impurities in the gas at the outlet of the secondary absorption tower 2. If the detection result of the concentration of gas impurities such as pentamethylenediamine at the outlet of the secondary absorption tower 2 exceeds the set value, the sulfuric acid solution is transported to the nozzle through an external pipeline connected to the nozzle of the tertiary absorption tower 3 to wash and absorb impurities in the exhaust gas, so that the detection result of the gas discharged from the outlet of the tertiary absorption tower 3 meets the requirements of environmental emission standards.

[0051] Reference Figure 2 The absorption tower, for example, a primary absorption tower, comprises a nozzle 13, a packing area 14 and a collection area 15 from top to bottom, and the three are interconnected. The collection area 15 is used to collect the washing liquid.

[0052] In one embodiment, the number of the spray heads in each stage of the absorption tower is three.

[0053] In another embodiment, the number of nozzles in each stage of the absorption tower is 1 to 6.

[0054] The washing liquid sprayed from the nozzles of each level of absorption tower passes through the packing area and is stored in the collection area.

[0055] The washing liquid can be applied. The washing liquid is transported from the collection area to the absorption tower where the washing liquid needs to be applied through a pipeline (not shown in the figure). The number of times of application is one, two, or more than two.

[0056] In one embodiment, the washing liquid of the primary absorption tower 1 , the secondary absorption tower 2 , and the tertiary absorption tower 3 is applied to any one, two, or three of the primary absorption tower 1 , the secondary absorption tower 2 , and the tertiary absorption tower 3 .

[0057] In another embodiment, the washing liquids of the primary absorption tower 1, the secondary absorption tower 2, and the tertiary absorption tower 3 are all water. The washing liquid in the collection area of ​​the secondary absorption tower 2 is transported to the nozzle of the primary absorption tower 1 through a pipeline, and the washing liquid in the collection area of ​​the tertiary absorption tower 3 is transported to the nozzle of the secondary absorption tower 2 through a pipeline.

[0058] As the number of applications increases, the concentration of impurities such as pentamethylenediamine in the washing liquid continues to increase. When the concentration of pentamethylenediamine in the washing liquid reaches the set value, the application is stopped. The application of washing liquid improves the absorption efficiency of the absorption tower and also reduces the water consumption of the entire system.

[0059] In one embodiment, the applied washing liquid is transported from the collection area of ​​the absorption tower through a pipeline to the production workshop of the main product for use as a raw material. The main product is pentamethylenediamine.

[0060] In one embodiment, a storage tank is disposed in the collection area, and the washing liquid is collected in the storage tank in the collection area.

[0061] Continue to refer to Figure 2 The packing area 14 of the absorption tower includes a support plate 141 and a packing layer 142 .

[0062] The number of the support plates 141 may be one, two, three or more than three, and the number of the corresponding filler layers 142 may be one, two, three or more than three.

[0063] The surface of the support plate has holes, and the hole diameter is smaller than the diameter of the filler. The spacing between any adjacent support plates is 3 to 12 meters. The filler layer is formed by the filler evenly piled on the surface of the support plate. The height of the filler layer is 0.5 to 2.5 meters. When the system is working, the washing liquid sprayed from the top nozzle of the absorption tower and the exhaust gas entering the absorption tower can pass through the packing area. The support plate and packing layer set in the packing area increase the contact time and contact area of ​​the washing liquid and the exhaust gas in the absorption tower, and complete the main absorption treatment of the exhaust gas in the packing area.

[0064] In one embodiment, referring to Figure 1 As shown, the number of support plates and packing layers in the primary absorption tower 1, the secondary absorption tower 2, and the tertiary absorption tower 3 are all three.

[0065] In another embodiment, the number of support plates and packing layers in the primary absorption tower 1 is four, the number of support plates and packing layers in the secondary absorption tower 2 is three, and the number of support plates and packing layers in the tertiary absorption tower 3 is two.

[0066] In one embodiment, the particle size of the filler is 1 to 10 cm. The surface and interior of the filler are provided with pores.

[0067] In one embodiment, the filler is a columnar structure with holes.

[0068] In one embodiment, the fillers of the primary absorption tower 1, the secondary absorption tower 2, and the tertiary absorption tower 3 are ceramic particles.

[0069] In another embodiment, the fillers of the primary absorption tower 1 and the secondary absorption tower 2 are ceramic particles, and the filler of the tertiary absorption tower 3 is polyethylene particles. This combination of fillers not only reduces the equipment investment cost, but also meets the corrosion resistance requirements.

[0070] Continue to refer to Figure 1 The existence of the induced draft device 4 can keep the system in a slightly negative pressure state, effectively prevent the odor of the gas in the system from being emitted, maintain a good production working environment and avoid the risk of gas leakage into the atmosphere.

[0071] In one embodiment, the air induction device 4 is a fan. The air volume and air pressure of the air induction device 4 can be set according to process requirements.

[0072] Continue to refer to Figure 2 A foam catcher 16 is installed inside the absorption tower between the gas outlet 12 and the nozzle 13.

[0073] In one embodiment, the foam catcher is a conventional device in the art. The structure of the foam catcher includes a wire mesh and a cotton cloth (not shown) arranged on the surface of the wire mesh. The wire mesh is a stainless steel wire mesh or a polyvinyl chloride corrugated mesh. The surface and interior of the cotton cloth have a hole structure that allows gas and liquid to pass through.

[0074] The foam catcher can improve the processing efficiency of the system and facilitate the long-term stable operation of the system. When the system is running, the water vapor in the exhaust gas condenses and gathers into droplets on the porous structure surface of the foam catcher, and then falls back into the tower. Since the impurities ammonia, pentamethylenediamine, and pentamethylenediamine salt in the exhaust gas are easily soluble in water, if the water content in the exhaust gas is high, the amount of ammonia, pentamethylenediamine, and pentamethylenediamine salt carried by the exhaust gas will increase. The foam catcher is set on one side of the gas outlet to effectively avoid the problem of high content of the above impurities in the exhaust gas discharged from the absorption tower, thereby reducing the difficulty of the next-level absorption tower to absorb and treat the exhaust gas. Therefore, the absorption efficiency of the exhaust gas by the absorption tower is improved by setting the foam catcher. In addition, by setting the foam catcher, the water vapor in the exhaust gas condenses back into the tower instead of entering the next-level absorption tower, avoiding the influence on the balance relationship of the water volume between different absorption towers, which is conducive to the long-term continuous operation of the multi-stage absorption tower.

[0075] The primary absorption tower 1, the secondary absorption tower 2, and the tertiary absorption tower 3 are made of stainless steel or FRP (glass reinforced plastic). The material of the absorption tower can withstand the corrosion of strong alkaline substances in the exhaust gas and different types of washing liquids. The washing liquid can be water or sulfuric acid solution, so it can be adjusted according to the actual situation, which greatly increases the process flexibility.

[0076] In one embodiment, the primary absorption tower 1 and the secondary absorption tower 2 are made of stainless steel, and the tertiary absorption tower 3 is made of FRP.

[0077] This system does not impose any particular restrictions on the composition of the exhaust gas.

[0078] In one embodiment, the waste gas is generated during the production of pentamethylenediamine, especially the waste gas generated during the extraction and purification of pentamethylenediamine. The waste gas components include at least two components of water, ammonia, pentamethylenediamine and a salt of pentamethylenediamine. The waste gas is alkaline.

[0079] When the waste gas absorption system of the utility model is working, under the action of the induced draft device 4, the first-stage absorption tower 1, the second-stage absorption tower 2, the third-stage absorption tower 3 and other absorption towers are in a negative pressure state. Waste gas enters the first-stage absorption tower 1 from the air inlet of the first-stage absorption tower 1, and the washing liquid enters the nozzle located at the top of the first-stage absorption tower 1 through the pipeline. The washing liquid sprayed by the nozzle contacts the waste gas from the bottom to the top of the first-stage absorption tower 1 in the packing area, and a large amount of impurities (such as ammonia, pentamethylenediamine and pentamethylenediamine salt) in the waste gas are absorbed. After the waste gas contacts the foam catcher, it enters the second-stage absorption tower 2 through the air outlet at the top of the tower through the pipeline, and the second waste gas absorption treatment is completed in the second-stage absorption tower 2 in the same way as the first-stage absorption tower 1. By analogy, the waste gas after the absorption treatment of the last absorption tower enters the induced draft device 4 through the air outlet and pipeline of the absorption tower and is discharged.

[0080] During operation, the droplets of washing liquid sprayed from the nozzle settle in the absorption tower. The surface of the settled droplets easily forms a film, that is, a "water film". The adsorption effect of the surface of the "water film" is strong, and the contact with the rising exhaust gas in the tower improves the absorption effect of impurities in the exhaust gas.

[0081] The washing liquid that has absorbed the impurities settles and enters the collection area of ​​the absorption tower. The washing liquid in the collection area can be transported to the nozzle of another absorption tower through a pipeline for reuse as washing liquid. The reused washing liquid can be transported to the production line of the main product such as pentamethylenediamine as raw material.

[0082] The utility model adopts a multi-stage, for example, three-stage, series-connected absorption tower, which improves the exhaust gas absorption efficiency, reduces the unit water consumption, and at the same time, the exhaust gas emission meets the environmental protection emission standard.

[0083] The above describes the implementation methods of the present invention. However, the present invention is not limited to the above implementation methods. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A waste gas absorption system, characterized in that: include: A first-stage absorption tower, a second-stage absorption tower, a third-stage absorption tower and an induced draft device, the gas outlets of the first-stage and second-stage absorption towers are respectively connected to the gas inlet of the next-stage absorption tower through pipelines, the gas outlet of the third-stage absorption tower is connected to the induced draft device through pipelines, the first-stage, second-stage and third-stage absorption towers each independently include a connected nozzle, a filling area and a collection area, the nozzle is connected to an external washing liquid pipeline or a washing liquid storage tank, and the washing liquid is transported from the collection area of ​​any absorption tower to the nozzle of any one or more absorption towers through the washing liquid pipeline for application.

2. The exhaust gas absorption system according to claim 1, characterized in that: Includes absorption towers with four or more levels.

3. The exhaust gas absorption system according to claim 1, characterized in that: The number of the nozzles is one, two, three or more than three.

4. The exhaust gas absorption system according to claim 1, characterized in that: The washing liquids of the primary absorption tower, the secondary absorption tower and the tertiary absorption tower are each independently selected from water or an acid solution.

5. The exhaust gas absorption system according to claim 1, characterized in that: The washing liquid in the collection area of ​​any absorption tower is transported to the nozzles of the primary absorption tower, the secondary absorption tower and / or the tertiary absorption tower for application.

6. The exhaust gas absorption system according to claim 5, characterized in that: The washing liquid in the collection area of ​​the secondary absorption tower is transported to the primary absorption tower through a pipeline, and the washing liquid in the collection area of ​​the tertiary absorption tower is transported to the secondary absorption tower through a pipeline.

7. The exhaust gas absorption system according to claim 1, characterized in that: The applied washing liquid is transported from the collection area of ​​the absorption tower through pipelines to the production workshop for use as raw material.

8. The exhaust gas absorption system according to claim 1, characterized in that: A foam catcher is installed between the gas outlet and the nozzle in the first-stage absorption tower, the second-stage absorption tower and / or the third-stage absorption tower.

9. The exhaust gas absorption system according to claim 1, characterized in that: The packing area includes a support plate and a packing layer.

10. The exhaust gas absorption system according to claim 9, characterized in that: The number of the support plate and the packing layer is one, two, three or more than three.

11. The exhaust gas absorption system according to claim 9, characterized in that: The support plate has holes on its surface, and the hole diameter is smaller than the filler diameter; and / or, The distance between adjacent support plates is 3 to 12 m; and / or, The height of the packing layer is 0.5 to 2.5 m; and / or, The particle size of the filler is 1 to 10 cm, and the surface and interior of the filler have holes.

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