Combined device for absorbing and treating glyoxylic acid synthesis reaction tail gas

Abstract

The utility model discloses a combined device for absorbing and treating glyoxylic acid synthesis reaction tail gas, and belongs to the technical field of chemical production devices and tail gas recycling. The device mainly comprises an absorption buffer tank, an A-stage absorption device, a B-stage absorption device, a C-stage absorption device, a D-stage absorption device, an induced draft fan, an activated carbon purification box, a harmless airflow outlet, a dilute nitric acid transfer tank and the like, the combined device for absorbing and treating glyoxylic acid synthesis reaction tail gas according to the technical scheme of the utility model effectively solves the problem of low absorption efficiency of a previous nitrogen oxide absorption device and the problem of low nitric acid content in absorption liquid, and is relatively beneficial to environmental protection and production cost control; the device also has the characteristics of safe process, convenience in operation and high production efficiency.

Description

Technical Field

[0001] This utility model belongs to the technical field of chemical production equipment and reaction tail gas recovery and reuse, and specifically relates to a combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction. Background Technology

[0002] Glyoxylic acid is an important organic synthesis intermediate, widely used in the synthesis of fragrances, pharmaceuticals, pesticides, food, varnish raw materials, dyes, plastic additives, etc. It can also be used in products such as vanillin, ethyl vanillin, mandelic acid, p-hydroxyphenylglycine, p-hydroxyphenylacetic acid, and allantoin.

[0003] The "glyoxal-nitric acid oxidation method" is currently a relatively mature and low-cost method for synthesizing glyoxylic acid. It involves the oxidation of glyoxal to glyoxylic acid by dilute nitric acid under the action of a composite catalyst. During this oxidation process, large amounts of nitrogen oxides such as nitric oxide and nitrogen dioxide are simultaneously generated. X .

[0004] The main chemical reaction equations for the synthesis of glyoxylic acid via the glyoxal-nitric acid oxidation process are as follows:

[0005] 3CHO-CHO + 2HNO3→ 3CHO-COOH + 2NO↑+ H2O,

[0006] 3CHO-COOH + 2HNO3 → 3HOOC-COOH + 2NO↑+ H2O,

[0007] 2NO + O2 → 2NO2,

[0008] NO + HNO3 → HNO2 + NO2.

[0009] In existing technologies, to prevent the escape of nitrogen oxide reaction tail gas, most treatment methods employ a 6-stage spray water absorption and a 2-stage alkaline solution absorption system. However, due to insufficient air supply and the slow and incomplete spray absorption process, a 2-stage alkaline solution absorption tower must be installed at the end of the tail gas absorption unit to prevent the escape of nitrogen oxides (NOx). X The sudden release of nitrogen oxides poses a threat to the atmospheric environment. A continuous six-stage water spray absorption system and a final two-stage alkaline solution absorption unit require significant space, equipment, and resources. Furthermore, the sodium nitrate and sodium nitrite solutions generated from the final two-stage alkaline solution absorption require further desalination and treatment. Therefore, it is necessary to innovate and improve existing nitrogen oxide absorption and treatment methods and devices. Summary of the Invention

[0010] To address the aforementioned problems, this utility model discloses a combined device for absorbing and treating the tail gas from the glyoxylic acid synthesis reaction. Its innovations mainly include: 1. Adding an air inlet at the front end of the tail gas pipeline immediately exiting the synthesis reactor to enhance the conversion of nitric oxide to nitrogen dioxide, thus facilitating the absorption of nitrogen dioxide by water; 2. Incorporating an absorption buffer tank before the tail gas enters the absorption tower to slow down and pre-absorb the high-speed tail gas flow; 3. Installing a gas-liquid mixing injector before the tail gas enters the absorption tower for forced absorption of nitrogen oxides before spray absorption. The absorption capacity of one gas-liquid mixing injector is equivalent to that of 3-4 spray absorption towers; 4. Incorporating an internal heat exchanger with cooling water in the absorption liquid tank to effectively cool the rapidly heated absorption liquid after forced absorption by the gas-liquid mixing injector, ensuring process safety and absorption efficiency; 5. Replacing the final alkaline spray absorption device with a urea solution spray absorption device, allowing the absorption liquid, whose main component is water, to be absorbed step-by-step forward, which is beneficial for the comprehensive utilization of water resources. The present invention provides a combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction. It effectively solves the problems of low absorption efficiency and incomplete absorption of previous nitrogen oxide absorption devices, and solves the problem of low nitric acid content in the absorption liquid. It is beneficial to environmental protection and production cost control. The present invention also features process safety, convenient operation and high production efficiency.

[0011] This utility model discloses a combined device for absorbing and treating the tail gas from the glyoxylic acid synthesis reaction. It includes: an absorption buffer tank, an air inlet, an air purifier, an airflow diffuser, a pure water control valve, an anti-entrainment damper, a liquid removal condenser, a Class A absorption device, a Class A absorption tower, a Class A absorbent liquid tank, a Class A gas-liquid mixing ejector, a Class A spray control valve, a spray head in the tower, a high-level spray head, a liquid removal net, a Class A circulating pump, and a Class A lifting valve; a Class B absorption device, a Class B absorption tower, a Class B absorbent liquid tank, a Class B circulating pump, a Class B gas-liquid mixer, a Class B spray control valve, and a Class B lifting valve; a Class C absorption device, a Class C absorption tower, a Class C absorbent liquid tank, an inlet inclined pipe, a Class C circulating pump, and a Class C lifting valve; and a Class D absorption device, a Class D absorption tower, and a Class D... The system comprises an absorbent tank, a Class D circulating pump, a Class D lifting valve, an induced draft fan, an activated carbon purification box, a harmless exhaust gas outlet, a dilute nitric acid transfer tank, a synthesis reactor, a reaction reflux condenser, and a reaction exhaust gas pipeline. Its distinguishing feature is that the absorbent buffer tank is equipped with an airflow disperser. The upper part of the absorbent buffer tank has three openings: one opening connects to the reaction exhaust gas pipeline via the airflow disperser and is connected to the synthesis reactor; the reaction exhaust gas pipeline has an air inlet; another opening connects to a pure water control valve; the central opening connects upwards via a pipeline to an anti-entrainment damper and a liquid removal condenser; the liquid removal condenser connects forward via a pipeline to the Class A gas-liquid mixing injector of the Class A absorption device; and a dilute nitric acid transfer pump is connected to the lower side of the absorbent buffer tank. The transfer pump is connected to the dilute nitric acid transfer tank via a dilute nitric acid transfer valve. The lower part of the A-level absorption device is the A-level absorbent tank, and the A-level absorption tower is installed directly above it. An internal heat exchanger is installed inside the A-level absorbent tank. An A-level circulating pump is installed on the lower outer side of the A-level absorbent tank. A spray head is installed in the middle of the A-level absorption tower, and a high-level spray head is installed at the top. A liquid removal screen is installed at the top of the tower. An A-level gas-liquid mixing ejector is installed on the outer side of the middle of the A-level absorption tower and connects forward to the spray head. The side opening of the A-level gas-liquid mixing ejector is connected to the reaction tail gas pipeline from the synthesis reactor. The A-level circulating pump is connected upwards to the A-level gas-liquid mixing ejector and the high-level spray head via pipelines. The A-level circulating pump is connected to the dilute nitric acid transfer tank via an A-level lifting valve. The top of the A-stage absorption tower is connected to the B-stage gas-liquid mixing injector of the B-stage absorption unit via a pipeline. The B-stage absorption unit has the same structure as the A-stage absorption unit. The lower part of the B-stage absorption unit is a B-stage absorbent tank, and the B-stage absorption tower is installed directly above the B-stage absorbent tank. A B-stage gas-liquid mixing injector is located on one side of the middle of the B-stage absorption tower. A B-stage circulation pump is located on the lower side of the B-stage absorbent tank, and the B-stage circulation pump is connected to the A-stage absorbent tank via a B-stage lift valve. The top of the B-stage absorption tower is connected to the inclined inlet pipe at the bottom of the C-stage absorption tower of the C-stage absorption unit via a pipeline. The lower part of the C-stage absorption unit is a C-stage absorbent tank, and the C-stage absorption tower is installed directly above the C-stage absorbent tank. An inclined inlet pipe is located on the lower side of the C-stage absorption tower.An inclined inlet pipe connects to the top of the B-stage absorption tower via a pipeline. A C-stage circulation pump is located on the lower side of the C-stage absorbent tank, connected to the upper part of the C-stage absorption tower via a pipeline. The C-stage circulation pump is connected to the B-stage absorbent tank via a C-stage lifting valve. The top of the C-stage absorption tower is connected to the D-stage absorption unit via a pipeline. The D-stage absorption unit has the same structure as the C-stage absorption unit. The lower part of the D-stage absorption unit is the D-stage absorbent tank, and the D-stage absorption tower is installed directly above it. A D-stage circulation pump is located on the lower side of the D-stage absorbent tank and connected to the C-stage absorbent tank via a pipeline and a D-stage lifting valve. An induced draft fan is connected to the top of the D-stage absorption tower, connected to the bottom of the activated carbon purification box via a pipeline. A harmless exhaust gas outlet is located at the top of the activated carbon purification box. The above-mentioned absorption devices and components are organically combined to constitute a combined device for absorbing and treating the exhaust gas from the glyoxylic acid synthesis reaction, as described in this utility model, capable of effectively absorbing and treating the nitrogen oxide exhaust gas from the glyoxylic acid synthesis reaction.

[0012] Preferably, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this utility model is characterized in that the anti-entrainment damper is a cylinder or ellipsoid with conical protrusions at both ends. The main body diameter of the anti-entrainment damper is 2.5 to 3.0 times the diameter of the connected tail gas pipeline, and the height is 80 to 100 cm. The material is enamel or 904 stainless steel. The purpose of designing the anti-entrainment damper is to slow down and pre-absorb the high-speed gas flow from the synthesis reactor, so as to prevent the high-speed gas flow from entraining the reactants and moving backward, thereby achieving efficient absorption of nitrogen oxide tail gas by the A-level to D-level absorption devices.

[0013] Preferably, the combined device for absorbing and treating the tail gas from the glyoxylic acid synthesis reaction described in this utility model is characterized in that the air inlet is connected to an air purifier, which is made of a PP pipe 80cm long and 100-125mm in diameter. The surface of the PP pipe has 100-150 10mm diameter holes drilled into it, and the surface of the PP pipe is covered with a single layer of 100-mesh filter cloth. This design aims to effectively prevent dust, flying debris, and other impurities from entering the tail gas absorption system after air purification, thereby ensuring the quality of the dilute nitric acid obtained from the tail gas absorption.

[0014] Preferably, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this utility model is characterized in that the airflow disperser is annular in appearance and is assembled by welding together rigid PP or PTFE pipes with a diameter of 40-50mm. Its installation position is 50-60cm away from the bottom of the absorption buffer tank. This design aims to ensure that the nitrogen oxide tail gas flow can be uniformly dispersed into the absorbent liquid in the absorption buffer tank, thereby achieving efficient absorption.

[0015] Preferably, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this utility model is characterized in that the downward half-surface of the airflow diffuser has 150-200 circular holes with a diameter of 5.0-10 mm. This design with circular holes on the downward half-surface aims to achieve efficient absorption of nitrogen oxide tail gas.

[0016] Preferably, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this utility model is characterized in that the internal heat exchanger is welded from PP pipes with a diameter of 15-20 mm, and the heat exchange area is 40-50 m². 2 The purpose of adding an internal heat exchanger for cooling is to reduce the large amount of heat generated by the forced absorption of exhaust gas by the gas-liquid mixing injector, thereby ensuring process safety and improving production efficiency.

[0017] Preferably, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this utility model is characterized in that the inclined inlet pipe is at a 30-60° angle to the absorption tower, and extends 5.0-10 cm into the absorption tower. This design aims to prevent localized blockage or poor airflow caused by the spray liquid entering the tail gas pipeline.

[0018] Preferably, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this utility model is characterized in that the liquid removal mesh is composed of 6 to 8 layers of acid-resistant stainless steel wire mesh, with a mass transfer area of ​​40 to 50 m². 2 The purpose of this design is to ensure that the high-speed airflow does not carry the liquid material out of the absorption device, thereby ensuring that the nitrogen oxide tail gas is effectively absorbed inside the absorption tower.

[0019] The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this utility model has the following significant beneficial effects: (1) Adding an air inlet to the front-end tail gas pipeline can effectively enhance the conversion of nitric oxide to nitrogen dioxide, which is beneficial for accelerating absorption. Adding an air purifier is beneficial for avoiding the introduction of impurities. (2) The design and installation of the absorption buffer tank can effectively reduce the speed of the high-speed tail gas flow for pre-absorption, which is very beneficial for the absorption of nitrogen oxides. (3) The design and installation of a gas-liquid mixing injector can force the absorption of nitrogen oxides, which is very beneficial for improving the absorption effect and production efficiency. (4) The design and installation of an internal heat exchanger in the absorption liquid tank can effectively cool down the absorption liquid that has rapidly increased in temperature after being forcibly absorbed by the gas-liquid mixing injector, which is beneficial for process safety and improving production efficiency. (5) The absorption liquid at the end is moved forward step by step, which can effectively ensure that a small amount of dilute nitric acid and pure water will not be wasted, which is very beneficial for the effective utilization of water resources and the reduction of energy consumption.

[0020] The present invention provides a combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction. It effectively solves the problems of low absorption efficiency and incomplete absorption of previous nitrogen oxide absorption devices, and solves the problem of low nitric acid content in the absorption liquid. It is beneficial to environmental protection and production cost control. The present invention also features process safety, convenient operation and high production efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0022] Figure 1 This is a schematic diagram of the process flow and planar structure of a combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction, as described in the technical solution of this utility model.

[0023] Figure 1 In the middle section: Absorption buffer tank 01, air purifier 11, air inlet 12, airflow diffuser 13, pure water control valve 14, anti-entrainment damper 15, liquid removal condenser 16, dilute nitric acid transfer pump 17, dilute nitric acid transfer valve 18, Class A absorption device 02, Class A gas-liquid mixing ejector 20, Class A absorbent tank 21, Class A absorption tower 22, Class A circulating pump 23, Class A spray control valve 24, spray head in the tower 25, high-level spray head 26, internal heat exchanger 27, liquid removal net 28, Class A lifting valve 29, Class B absorption device 03, Class B absorption tower 31, Class B absorbent Tank 30, Class B circulating pump 32, Class B gas-liquid mixer 33, Class B spray control valve 35, Class B lifting valve 34, Class C absorption device 04, Class C absorption tower 41, Class C inlet inclined pipe 42, Class C absorbent tank 40, Class C circulating pump 43, Class C lifting valve 44, Class D absorption device 05, Class D absorption tower 51, Class D absorbent tank 50, Class D circulating pump 52, Class D lifting valve 53, induced draft fan 06, activated carbon purification box 07, harmless tail gas outlet 71, dilute nitric acid transfer tank 08, synthesis reactor 09, reaction reflux condenser 91, reaction tail gas pipeline 92. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this utility model clearer, the following description is provided in conjunction with... Figure 1 The specific embodiments of this implementation will be further described.

[0025] This specific embodiment describes a combined device for absorbing and treating the tail gas from the glyoxylic acid synthesis reaction. It includes: an absorption buffer tank 01, an air purifier 11, an air inlet 12, an airflow diffuser 13, a pure water control valve 14, an anti-entrainment damper 15, a liquid removal condenser 16, a dilute nitric acid transfer pump 17, a dilute nitric acid transfer valve 18, a Class A absorption device 02, a Class A gas-liquid mixing ejector 20, a Class A absorption liquid tank 21, a Class A absorption tower 22, a Class A circulating pump 23, a Class A spray control valve 24, spray heads in the tower 25, high-level spray heads 26, an internal heat exchanger 27, a liquid removal net 28, a Class A lifting valve 29, and a Class B absorption device. Device 03, Class B Absorption Tower 31, Class B Absorption Liquid Tank 30, Class B Circulation Pump 32, Class B Gas-Liquid Mixer 33, Class B Spray Control Valve 35, Class B Lifting Valve 34, Class C Absorption Device 04, Class C Absorption Tower 41, Class C Inlet Inclined Pipe 42, Class C Absorption Liquid Tank 40, Class C Circulation Pump 43, Class C Lifting Valve 44, Class D Absorption Device 05, Class D Absorption Tower 51, Class D Absorption Liquid Tank 50, Class D Circulation Pump 52, Class D Lifting Valve 53, Exhaust Fan 06, Activated Carbon Purification Box 07, Harmless Tail Gas Outlet 71, Dilute Nitric Acid Transfer Tank 08, Synthesis Reactor 09, Reaction Reflux Condenser 91, Reaction Tail Gas Pipeline 92.

[0026] The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this specific embodiment is characterized in that the absorption buffer tank 01 is equipped with an airflow disperser 13, and the upper part of the absorption buffer tank 01 has three openings. One opening is connected to the reaction tail gas pipeline 92 and the synthesis reaction vessel 09 through the airflow disperser 13. The reaction tail gas pipeline 92 is equipped with an air inlet 12. The other opening is connected to a pure water control valve 14. The middle opening is connected to an anti-entrainment damper 15 and a liquid removal condenser 16 in sequence through a pipeline. The liquid removal condenser 16 is connected to the A-level gas-liquid mixing injector 20 of the A-level absorption device 02 through a pipeline. The lower side of the absorption buffer tank 01 is connected to a dilute nitric acid transfer pump 17. The dilute nitric acid transfer pump 17 is connected to the dilute nitric acid transfer tank 08 via the dilute nitric acid transfer valve 18. The lower part of the A-level absorption device 02 is the A-level absorption liquid tank 21. An A-level absorption tower 22 is installed directly above the absorption liquid tank 21. An internal heat exchanger 27 is installed inside the A-level absorption liquid tank 21. An A-level circulating pump 23 is installed on the lower outer side of the A-level absorption liquid tank 21. A spray head 25 is installed in the middle of the A-level absorption tower 22, and a high-level spray head 26 is installed at the top. A liquid removal screen 28 is installed at the top of the tower. An A-level gas-liquid mixing ejector 20 is installed on the outer side of the middle of the A-level absorption tower 22 and connects forward to the spray head 25. The side opening of the A-level gas-liquid mixing ejector 20 is connected to the reaction tail gas pipeline 92 from the synthesis reactor 09. The A-level circulating pump... The A-level gas-liquid mixing injector 20 and the high-level spray head 26 are connected upwards via pipes. The A-level circulating pump 23 is connected to the dilute nitric acid transfer tank 08 via the A-level lifting valve 29. The top of the A-level absorption tower 22 is connected to the B-level gas-liquid mixing injector 33 of the B-level absorption device 03 via a pipe. The B-level absorption device 03 has the same structure as the A-level absorption device 02. The lower part of the B-level absorption device 03 is the B-level absorbent tank 30. The B-level absorption tower 31 is installed directly above the B-level absorbent tank 30. The B-level gas-liquid mixing injector 33 is installed on one side of the middle of the B-level absorption tower 31. The B-level circulating pump 32 is installed on the lower side of the B-level absorbent tank 30. The B-level circulating pump 32 is connected to the A-level absorbent tank via the B-level lifting valve 34. 21. The top of the B-stage absorption tower 31 is connected via a pipe to the inclined inlet pipe 42 at the bottom of the C-stage absorption tower 41 of the C-stage absorption device 04. The lower part of the C-stage absorption device 04 is a C-stage absorbent tank 40, and the C-stage absorption tower 41 is installed directly above the C-stage absorbent tank 40. An inclined inlet pipe 42 is located on the lower side of the C-stage absorption tower 41, and is connected to the top of the B-stage absorption tower 31 via a pipe. A C-stage circulation pump 43 is located on the lower side of the C-stage absorbent tank 40, and is connected to the upper part of the C-stage absorption tower 41 via a pipe. The C-stage circulation pump 43 is connected to the B-stage absorbent tank 30 via a C-stage lifting valve 44. The top of the C-stage absorption tower 41 is connected via a pipe to the D-stage absorption tower 51 of the D-stage absorption device 05.The D-level absorption device 05 is structurally identical to the C-level absorption device 04. The lower part of the D-level absorption device 05 is a D-level absorbent tank 50, and a D-level absorption tower 51 is installed directly above the D-level absorbent tank 50. A D-level circulating pump 52 is located on the lower side of the D-level absorbent tank 50 and is connected to the C-level absorbent tank 40 via a pipe and a D-level lifting valve 53. An induced draft fan 06 is connected to the top of the D-level absorption tower 51, and the induced draft fan 06 is connected to the bottom of an activated carbon purification box 07 via a pipe. A harmless exhaust gas outlet 71 is located at the top of the activated carbon purification box 07. The above-mentioned absorption devices and components are organically combined to constitute a combined device for absorbing and treating the exhaust gas from the glyoxylic acid synthesis reaction, as described in this utility model, capable of effectively absorbing and treating the nitrogen oxide exhaust gas from the glyoxylic acid synthesis reaction.

[0027] Furthermore, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this specific embodiment is characterized in that the anti-entrainment damper is a cylinder or ellipsoid with conical protrusions at both ends. The main body diameter of the anti-entrainment damper is 2.5 to 3.0 times the diameter of the connected tail gas pipeline, and the height is 80 to 100 cm. The material is enamel or 904 stainless steel. The purpose of designing the anti-entrainment damper is to slow down and pre-absorb the high-speed gas flow from the synthesis reactor, so as to prevent the high-speed gas flow from carrying the reactants backward, thereby achieving efficient absorption of nitrogen oxide tail gas by the A-level to D-level absorption devices.

[0028] Furthermore, the combined device for absorbing and treating the tail gas from the glyoxylic acid synthesis reaction described in this specific embodiment is characterized in that the air inlet is connected to an air purifier, which is made of a PP pipe 80cm long and 100-125mm in diameter. The surface of the PP pipe has 100-150 10mm diameter holes drilled into it, and the surface of the PP pipe is covered with a single layer of 100-mesh filter cloth. The purpose of this design is to effectively prevent dust, flying debris, and other impurities from entering the tail gas absorption system after air purification, thereby ensuring the quality of the dilute nitric acid obtained from the tail gas absorption.

[0029] Furthermore, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this specific embodiment is characterized in that the airflow disperser is annular in appearance and is assembled by welding together rigid PP or PTFE pipes with a diameter of 40-50mm. Its installation position is 50-60cm away from the bottom of the absorption buffer tank. This design aims to ensure that the nitrogen oxide tail gas flow can be uniformly dispersed into the absorbent liquid in the absorption buffer tank, thereby achieving efficient absorption.

[0030] Furthermore, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this specific embodiment is characterized in that the downward half-surface of the airflow diffuser has 150-200 circular holes with a diameter of 5.0-10 mm. This design of opening circular holes on the downward half-surface is also intended to achieve efficient absorption of nitrogen oxide tail gas.

[0031] Furthermore, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this specific embodiment is characterized in that the internal heat exchanger is welded from PP pipes with a diameter of 15-20 mm, and the heat exchange area is 40-50 m². 2 The purpose of adding an internal heat exchanger for cooling is to reduce the large amount of heat generated by the forced absorption of exhaust gas by the gas-liquid mixing injector, thereby ensuring process safety and improving production efficiency.

[0032] Furthermore, the combined device for absorbing and treating the tail gas from the glyoxylic acid synthesis reaction described in this specific embodiment is characterized in that the inclined inlet pipe is at a 30-60° angle to the absorption tower, and extends 5.0-10 cm into the absorption tower. This design aims to prevent localized blockage or airflow obstruction caused by the spray liquid entering the tail gas pipeline.

[0033] Furthermore, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this specific embodiment is characterized in that the liquid removal mesh is composed of 6 to 8 layers of acid-resistant stainless steel wire mesh, with a mass transfer area of ​​40 to 50 m². 2 The purpose of this design is to ensure that the high-speed airflow does not carry the liquid material out of the absorption device, thereby ensuring that the nitrogen oxide tail gas is effectively absorbed inside the absorption tower.

[0034] Furthermore, the combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this specific embodiment can be simply described as follows: The tail gas of glyoxylic acid synthesis reaction from the synthesis reactor 09 enters the absorption buffer tank 01, which is pre-filled with 1 / 2 water, through the reaction reflux condenser 91 and the reaction tail gas pipeline 92. Then, it passes through the airflow disperser 13 to disperse small bubbles, which are partially absorbed by the water. The initially absorbed reaction tail gas travels along the tail gas pipeline through the anti-entrainment damper 15 and the liquid removal condenser 16 to the A-stage absorption device 02. It is forcibly absorbed by the negative pressure generated by the high-speed jet flow of the gas-liquid mixing ejector 24 and forcibly carried into the A-stage absorption tower 22. The airflow is from bottom to top, and the absorbent liquid is from top to bottom. The water absorption reaction of nitrogen oxides is completed in the absorption tower. The tail gas from the A-stage absorption tower 22 then passes through the B-stage absorption device 03, the C-stage absorption device 04, and the D-stage absorption device 05. The solution is efficiently absorbed and then purified by the induced draft fan 06 and activated carbon purification box 07 before being discharged from the harmless exhaust gas outlet 71. When the concentration of the absorbent in the absorption buffer tank 01 reaches the technical specifications for dilute nitric acid, the dilute nitric acid transfer pump 17 is started to transfer a certain concentration of dilute nitric acid to the dilute nitric acid transfer tank 08. When the concentration of the absorbent in the A-level absorbent tank 21 reaches the technical specifications for dilute nitric acid, the A-level circulation pump 23 is started to transfer the dilute nitric acid to the dilute nitric acid transfer tank 08. Then, the B-level circulation pump 32 is started to transfer the absorbent in the B-level absorbent tank 30 to the A-level absorbent tank 21 using a similar operation. Next, the C-level circulation pump 43 is started to transfer the absorbent in the C-level absorbent tank 40 to the B-level absorbent tank 30. Then, the D-level transfer pump 52 is started to transfer the absorbent in the D-level absorbent tank 50 to the C-level absorbent tank 40, and then new pure water is added to the D-level absorbent tank 50. In this way, the tail gas from the glyoxylic acid synthesis reaction moves step by step from the absorption buffer tank 01 to the D-stage absorption device 05, and the concentration of nitrogen oxides gradually decreases. Meanwhile, the absorbent liquid, whose effective component is dilute nitric acid, moves step by step from the D-stage absorption device 05 to the dilute nitric acid transfer tank 08, so that the effective concentration of dilute nitric acid gradually reaches the technical requirements.

[0035] The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction described in this utility model has the following significant beneficial effects: (1) Adding an air inlet to the front-end tail gas pipeline can effectively enhance the conversion of nitric oxide to nitrogen dioxide, which is beneficial for accelerating absorption. Adding an air purifier is beneficial for avoiding the introduction of impurities. (2) The design and installation of the absorption buffer tank can effectively reduce the speed of the high-speed tail gas flow for pre-absorption, which is very beneficial for the absorption of nitrogen oxides. (3) The design and installation of a gas-liquid mixing injector can force the absorption of nitrogen oxides, which is very beneficial for improving the absorption effect and production efficiency. (4) The design and installation of an internal heat exchanger in the absorption liquid tank can effectively cool down the absorption liquid that has rapidly increased in temperature after being forcibly absorbed by the gas-liquid mixing injector, which is beneficial for process safety and improving production efficiency. (5) The absorption liquid at the end is moved forward step by step, which can effectively ensure that a small amount of dilute nitric acid and pure water will not be wasted, which is very beneficial for the effective utilization of water resources and the reduction of energy consumption.

[0036] This device, as described in the present invention, is a combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction. It effectively solves the problems of low absorption efficiency and incomplete absorption of previous nitrogen oxide absorption devices, and also solves the problem of low nitric acid content in the absorption liquid. It is more beneficial to environmental protection and production cost control.

[0037] This device, a combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction as described in the present invention, also features process safety, convenient operation, and high production efficiency.

[0038] Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model shall be included within the protection scope of this utility model. The protection scope of this utility model shall conform to the widest range consistent with the principles and novel features described herein.

Claims

1. A combined device for absorbing and treating the tail gas from the glyoxylic acid synthesis reaction, comprising: Absorption buffer tank, air inlet, air purifier, airflow diffuser, pure water control valve, anti-entrainment damper, liquid removal condenser, Class A absorption device, Class A absorption tower, Class A absorbent tank, Class A gas-liquid mixing ejector, Class A spray control valve, in-tower spray head, high-level spray head, liquid removal net, Class A circulating pump, Class A lifting valve; Class B absorption device, Class B absorption tower, Class B absorbent tank, Class B circulating pump, Class B gas-liquid mixer, Class B spray control valve, Class B lifting valve; Class C absorption device, Class C absorption tower, Class C absorbent tank, inclined inlet pipe, Class C circulating pump, Class C lifting valve; Class D absorption device, Class D absorption tower, Class D absorbent tank, Class D circulating pump, Class D lifting valve, induced draft fan, activated carbon purification box, harmless exhaust gas outlet, dilute nitric acid. The apparatus comprises a transfer tank, a synthesis reactor, a reaction reflux condenser, and a reaction tail gas pipeline. Its characteristic feature is that the absorption buffer tank is equipped with an airflow disperser. The upper part of the absorption buffer tank has three openings: one opening connects to the reaction tail gas pipeline and the synthesis reactor via the airflow disperser, and the reaction tail gas pipeline has an air inlet; another opening connects to a pure water control valve; the central opening connects upwards via a pipeline to an anti-entrainment damper and a liquid removal condenser; the liquid removal condenser connects forward via a pipeline to the A-level gas-liquid mixing injector of the A-level absorption device; a dilute nitric acid transfer pump is connected to the lower side of the absorption buffer tank; the dilute nitric acid transfer pump is connected to a dilute nitric acid transfer tank via a dilute nitric acid transfer valve; and the lower part of the A-level absorption device is an A-level absorbent liquid tank. An A-stage absorption tower is installed directly above the absorbent tank. An internal heat exchanger is installed inside the A-stage absorbent tank. An A-stage circulating pump is installed on the lower outer side of the A-stage absorbent tank. A spray head is installed in the middle of the A-stage absorption tower, and a high-level spray head is installed at the top. A liquid removal screen is installed at the top of the tower. An A-stage gas-liquid mixing ejector is installed on the outer side of the middle of the A-stage absorption tower and connected forward to the spray head. The side opening of the A-stage gas-liquid mixing ejector is connected to the reaction tail gas pipeline from the synthesis reactor. The A-stage circulating pump is connected upwards to the A-stage gas-liquid mixing ejector and the high-level spray head via pipelines. The A-stage circulating pump is connected to a dilute nitric acid transfer tank via an A-stage lifting valve. The top of the A-stage absorption tower is connected to the B-stage gas-liquid mixing ejector of the B-stage absorption unit via pipelines. The structure of the B-stage absorption unit is identical to that of the A-stage absorption unit. The lower part of the B-stage absorption unit consists of a B-stage absorbent tank, with a B-stage absorption tower mounted directly above it. A B-stage gas-liquid mixing injector is located on one side of the middle of the B-stage absorption tower. A B-stage circulation pump is located on the lower side of the B-stage absorbent tank, connected to the A-stage absorbent tank via a B-stage lift valve. The top of the B-stage absorption tower is connected via a pipe to the inclined inlet pipe at the bottom of the C-stage absorption tower in the C-stage absorption unit. Similarly, the lower part of the C-stage absorption unit consists of a C-stage absorbent tank, with a C-stage absorption tower mounted directly above it. An inclined inlet pipe is located on the lower side of the C-stage absorption tower, connected to the top of the B-stage absorption tower via a pipe. A C-stage circulation pump is located on the lower side of the C-stage absorbent tank.The C-level circulating pump is connected to the upper part of the C-level absorption tower via a pipeline. The C-level circulating pump is connected to the B-level absorbent tank via a C-level lifting valve. The top of the C-level absorption tower is connected to the D-level absorption tower of the D-level absorption unit via a pipeline. The D-level absorption unit has the same structure as the C-level absorption unit. The lower part of the D-level absorption unit is the D-level absorbent tank, and the D-level absorption tower is installed directly above the D-level absorbent tank. The D-level circulating pump is located on the lower side of the D-level absorbent tank and is connected to the C-level absorbent tank via a pipeline and a D-level lifting valve. The top of the D-level absorption tower is connected to an induced draft fan, which is connected to the bottom of the activated carbon purification box via a pipeline. The activated carbon purification box has a harmless exhaust gas outlet at the top.

2. The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction according to claim 1, characterized in that, The anti-clamping damper is a cylinder or ellipsoid with conical protrusions at both ends. The main body diameter of the anti-clamping damper is 2.5 to 3.0 times the diameter of the connected exhaust pipe, and the height is 80 to 100 cm. The material is enamel or 904 stainless steel.

3. The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction according to claim 1, characterized in that, The air inlet is connected to an air purifier, which is made of a PP pipe that is 80cm long and 100-125mm in diameter. The surface of the PP pipe has 100-150 holes with a diameter of 10mm, and the surface of the PP pipe is covered with a single layer of filter cloth with a pore size of 100 mesh.

4. The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction according to claim 1, characterized in that, The airflow diffuser is ring-shaped and is assembled by welding together rigid PP or PTFE pipes with a diameter of 40-50mm. Its installation position is 50-60cm away from the bottom of the absorption buffer tank.

5. The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction according to claim 1, characterized in that, The downward-facing half-surface of the airflow diffuser has 150 to 200 circular holes with a diameter of 5.0 to 10 mm.

6. The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction according to claim 1, characterized in that, The internal heat exchanger is welded from PP pipes with a diameter of 15-20mm, and has a heat exchange area of ​​40-50m². 2 .

7. The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction according to claim 1, characterized in that, The inclined tube leading into the absorption tower is at an angle of 30 to 60° to the absorption tower, and extends 5.0 to 10 cm into the absorption tower.

8. The combined device for absorbing and treating the tail gas of glyoxylic acid synthesis reaction according to claim 1, characterized in that, The liquid removal mesh is composed of 6 to 8 layers of acid-resistant stainless steel wire mesh, with a mass transfer area of ​​40 to 50 m². 2 .

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