Acrylonitrile tail gas recovery system suitable for multi-tank-area storage

Abstract

The utility model discloses an acrylonitrile tail gas recovery system suitable for multi-tank-area storage, which consists of three sets of condensation adsorption systems connected in parallel for use and a set of catalytic oxidation system, the system comprises a double-channel three-stage condensation adsorption device, a mixing tank, a tail gas heat exchanger, an electric heater, a catalytic oxidation reactor, an air cooling cooler I, an SCR reactor, an air cooling cooler II, a fan and an exhaust funnel. The parallel double-channel three-stage condensation adsorption device is arranged, so that refrigeration and defrosting can be alternately carried out, continuous refrigeration operation of the device is ensured, defrosting is rapid, condensation treatment of oil gas is not affected by defrosting, the device is economical, energy-saving, safe and reliable, and continuous and efficient operation of the cold box is ensured all the time; a purified gas pipeline is arranged in the tail gas heat exchanger, purified gas exchanges heat with initial waste gas, the waste heat utilization rate is increased, and cost is saved.

Description

Technical Field

[0001] The utility model relates to a tail gas recovery system, in particular to an acrylonitrile tail gas recovery system suitable for multi-tank area storage. Background Art

[0002] In the current storage environment, multiple tank areas are usually set up to store various hazardous chemicals. Each tank area requires an exhaust gas treatment system. However, in order to save the cost of exhaust gas treatment, the tank areas share a set of exhaust gas treatment devices to complete exhaust gas recovery and treatment. This makes it very easy for the exhaust gas treatment device to be overloaded during the actual unloading, material collection, and tank emptying process, and the treatment capacity is insufficient, which cannot meet the requirements of safe operation and environmental protection. Utility Model Content

[0003] The technical problem to be solved by the utility model is to provide an acrylonitrile tail gas recovery system which has a reasonable design, improves the tail gas treatment capacity and efficiency and is suitable for multi-tank area storage in view of the deficiencies of the prior art.

[0004] In order to achieve the above purpose, the utility model adopts the following technical solutions:

[0005] The invention discloses an acrylonitrile tail gas recovery system suitable for storage in multiple tank areas, which is characterized in that it comprises a dual-channel three-stage condensation adsorption device, a mixing tank, a tail gas heat exchanger, an electric heater, a catalytic oxidation reactor, an air-cooled cooler I, an SCR reactor, an air-cooled cooler II, a fan and an exhaust pipe which are connected in sequence.

[0006] The dual-channel three-stage condensation adsorption device includes a channel A three-stage condensing unit and a channel B three-stage condensing unit arranged in parallel, and an adsorption tank connected to the channel A three-stage condensing unit and the channel B three-stage condensing unit connected in parallel; the channel A three-stage condensing unit and the channel B three-stage condensing unit are both provided with a primary cold box, a secondary cold box and a tertiary cold box connected in sequence, the primary cold box, the secondary cold box and the tertiary cold box are connected in pairs, the primary cold box of the channel A three-stage condensing unit and the channel B three-stage condensing unit is connected to the acrylonitrile tail gas recovery pipeline manifold of multiple tank areas through a tee, the tertiary cold box of the channel A three-stage condensing unit and the channel B three-stage condensing unit is connected to the input end of the adsorption tank through a tee I, and the output end of the adsorption tank is connected to the mixing tank.

[0007] The exhaust gas heat exchanger includes a shell and a heat exchange pipe for passing purified exhaust gas. The heat exchange pipe is installed in the shell. The shell is provided with an initial exhaust gas inlet connected to a mixing tank and an initial exhaust gas outlet connected to an electric heater. One end of the heat exchange pipe is provided with a purified exhaust gas outlet connected to an SCR reactor, and the other end of the heat exchange pipe is provided with a purified exhaust gas inlet connected to an air-cooled cooler II.

[0008] The technical problem to be solved by the utility model can also be achieved through the following technical scheme: the adsorption tank is provided with a tank body, an air inlet is provided at the bottom of the tank body, an air outlet is provided at the top of the tank body, at least two layers of composite adsorbent adsorption components are installed in the tank body, and a gas buffer cavity is provided above and below each layer of composite adsorbent adsorption components. The air inlet is connected to a vacuum analysis pipeline through a tee II, and the vacuum analysis pipeline is respectively connected to the inlet end of a vacuum pump and a dual-channel three-stage condensation adsorption device through a tee III.

[0009] The technical problem to be solved by the utility model can also be achieved through the following technical scheme. The composite adsorbent adsorption assembly includes a lower supporting mesh frame, a columnar composite adsorbent and an upper pressure plate. The lower supporting mesh frame is fixedly connected to a fixing ring arranged on the inner wall of the tank body. The columnar composite adsorbent is placed in the lower supporting mesh frame. The pressure plate covers the columnar composite adsorbent, and a plurality of ventilation holes are opened on the pressure plate.

[0010] The technical problem to be solved by the utility model can also be achieved by the following technical solution: an ammonia spray gun for spraying ammonia solution into the SCR reactor is installed at the inlet of the SCR reactor, and the ammonia spray gun is connected to an ammonia metering pump through a gas-liquid mixer.

[0011] The technical problem to be solved by the utility model can also be achieved through the following technical solution: at least two adsorption tanks are provided, and the two adsorption tanks are arranged in parallel.

[0012] The technical problem to be solved by the utility model can also be achieved through the following technical scheme: the purified exhaust gas outlet of the heat exchange pipeline is connected with an air-cooled cooler II and an exhaust pipe in sequence, and the air-cooled cooler II is connected to the exhaust pipe through a fan.

[0013] Compared with the prior art, the utility model has the following technical effects:

[0014] First, by setting up three sets of dual-channel three-stage condensation adsorption devices used in parallel, each condensation adsorption device is activated at the same time to expand the scale of waste gas treatment and improve the waste gas treatment capacity and efficiency; the dual-channel three-stage condensation adsorption device can alternately perform refrigeration and defrosting to ensure continuous refrigeration operation of the device, fast defrosting and no impact on the condensation treatment of oil and gas due to defrosting, economical and energy-saving, safe and reliable, ensuring that the cold box always operates continuously and efficiently, and defrosting is carried out using the heat of the exhaust gas itself, and no longer using the high-temperature refrigerant steam discharged from the refrigeration compressor, so that defrosting is no longer restricted by refrigeration, and the whole machine is economical, energy-saving and efficient;

[0015] Second, by installing an exhaust gas heat exchanger and an electric heater, the efficiency and effect of the later exhaust gas treatment are improved. A purified gas pipeline is installed in the exhaust gas heat exchanger to exchange heat between the purified gas and the initial exhaust gas, making full use of the heat in the exhaust gas, improving the waste heat utilization rate and saving costs.

[0016] Thirdly, by installing a fan, the exhaust gas is transported from the inlet of the device to the terminal exhaust fan. Through pressure control, the system pressure is guaranteed to decrease from high to low. The exhaust gas always maintains a pressure gradient from high to low in each unit operation such as transportation, condensation, mixing, heating, reaction, heat recovery, and heat dissipation, and there will be no pressure build-up or gas blowby. The catalytic oxidation reactor uses the equipment manufacturer's ultra-high activity JD-888 catalytic oxidation catalyst, and the removal rate of acrylonitrile exhaust gas at around 400°C can reach more than 99.95%. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of an acrylonitrile tail gas recovery system suitable for multi-tank storage areas according to the utility model;

[0018] Figure 2 This is the structural diagram of the adsorption tank.

[0019] In the figure: 1-dual-channel three-stage condensation adsorption device, 2-first-stage cold box, 3-second-stage cold box, 4-third-stage cold box, 5-adsorption tank, 6-vacuum pump, 7-mixing tank, 8-exhaust heat exchanger, 9-SCR reactor, 10-electric heater, 11-air-cooled cooler I, 12-catalytic oxidation reactor, 13-air-cooled cooler II, 14-fan, 15-exhaust duct, 16-tank body, 17-air inlet, 18-air outlet, 19-lower supporting mesh frame, 20-upper pressure plate, 21-fixing ring, 22-vacuum analysis pipeline, 23-gas buffer chamber. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0021] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, 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, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0022] Reference Figure 1 and Figure 2, an acrylonitrile tail gas recovery system suitable for multi-tank storage, the system comprises a dual-channel three-stage condensation adsorption device 1, a mixing tank 7, a tail gas heat exchanger 8, an electric heater 10, a catalytic oxidation reactor 12, an air-cooled cooler I 11 and an SCR reactor 9 connected in sequence, wherein the electric heater 10, the catalytic oxidation reactor, i.e., a CO reactor 12, the air-cooled cooler I 11 and the SCR reactor 9 can adopt existing public or commercially available products or structures;

[0023] The dual-channel three-stage condensation adsorption device 1 includes a channel A three-stage condensing unit and a channel B three-stage condensing unit arranged in parallel, and an adsorption tank connected to the channel A three-stage condensing unit and the channel B three-stage condensing unit connected in parallel; the channel A three-stage condensing unit and the channel B three-stage condensing unit are both provided with a first-stage cold box 2, a second-stage cold box 3 and a third-stage cold box 4 connected in sequence, the first-stage cold box 2, the second-stage cold box 3 and the third-stage cold box 4 are connected in pairs, the first-stage cold box of the channel A three-stage condensing unit and the channel B three-stage condensing unit is connected to the acrylonitrile tail gas recovery pipeline manifold of multiple tank areas through a tee, the third-stage cold box of the channel A three-stage condensing unit and the channel B three-stage condensing unit is connected to the input end of the adsorption tank through a tee I, and the output end of the adsorption tank is connected to the mixing tank, and corresponding valves can be set between the above pipelines for control according to the tail gas treatment scale.

[0024] The exhaust gas heat exchanger 8 includes a shell and a heat exchange pipe for passing purified exhaust gas. The heat exchange pipe is installed in the shell. The shell is provided with an initial exhaust gas inlet connected to the mixing tank and an initial exhaust gas outlet connected to the electric heater. One end of the heat exchange pipe is provided with a purified exhaust gas outlet connected to the SCR reactor, and the other end of the heat exchange pipe is provided with a purified exhaust gas inlet connected to the air-cooled cooler II, so that the purified gas and the initial exhaust gas can exchange heat and improve the utilization rate of thermal energy.

[0025] The adsorption tank is provided with a tank body 16, an air inlet 17 is provided at the bottom of the tank body 16, an air outlet 18 is provided at the top of the tank body 16, at least two layers of composite adsorbent adsorption components are installed in the tank body 16, and a gas buffer chamber 23 is provided above and below each layer of composite adsorbent adsorption components. A vacuum analysis pipeline 22 is connected to the air inlet through a tee II, and the vacuum analysis pipeline 22 is respectively connected to the vacuum pump 6 and the inlet end of the dual-channel three-stage condensation adsorption device 1 through a tee III.

[0026] The composite adsorbent adsorption assembly includes a lower supporting mesh frame 19, a columnar composite adsorbent and an upper pressure plate 20. The lower supporting mesh frame 19 is fixedly connected to a fixing ring 21 arranged on the inner wall of the tank body. The columnar composite adsorbent is placed in the lower supporting mesh frame 19. The upper pressure plate 20 covers the columnar composite adsorbent. A plurality of ventilation holes are opened on the upper pressure plate to reduce the flow rate of the exhaust gas in the adsorption tank and improve the adsorption efficiency of the columnar composite adsorbent.

[0027] An ammonia spray gun for spraying ammonia solution into the SCR reactor is installed at the inlet of the SCR reactor. The ammonia spray gun is connected to an ammonia metering pump through a gas-liquid mixer to improve the tail gas treatment efficiency and effect.

[0028] At least two adsorption tanks 5 are provided, and the two adsorption tanks 5 are arranged in parallel to improve the adsorption efficiency.

[0029] The purified tail gas outlet of the heat exchange pipeline is connected with an air-cooled cooler II 13 and an exhaust pipe in sequence, and the air-cooled cooler II is connected with the exhaust pipe through a fan to improve the tail gas treatment effect.

[0030] The process of the acrylonitrile tail gas recovery system described in the utility model is as follows:

[0031] The acrylonitrile waste gas discharged from the storage tanks in multiple tank areas is merged into three sets of dual-channel three-stage condensation adsorption devices used in parallel, with a single set processing scale of 2400Nmh, to recover acrylonitrile in the waste gas. The waste gas first undergoes three-stage condensation (the temperature of the first-stage cold box is controlled at -5℃ (adjustable), the temperature of the second-stage cold box is controlled at -20℃ (adjustable), and the temperature of the third-stage cold box is controlled at -70℃ (adjustable)); after three-stage condensation, the temperature of the acrylonitrile waste gas is <-60℃, and the concentration of the acrylonitrile waste gas is <1106mg / m 3 ; Then through adsorption by adsorbent (the adsorption tank is regularly vacuumed and analyzed, and the high-concentration acrylonitrile waste gas analyzed is again recovered through three-stage condensation) to control the acrylonitrile concentration in the waste gas to ≤1000mg / m 3 The exhaust gas leaving the adsorption tank and the air (maximum air flow rate is 2400 m / h) are mixed in the mixing tank.

[0032] The mixed exhaust gas is preheated by the exhaust gas heat exchanger, and then enters the electric heater to be heated to 400°C (only used when starting up or when energy is insufficient), and then enters the catalytic oxidation reactor, where a catalytic oxidation reaction is carried out. The reaction bed temperature is controlled at 400°C to convert volatile organic matter into carbon dioxide and water. The exhaust gas after the catalytic oxidation reaction is about 430°C, and enters the inlet flue of the SCR reactor after being cooled by the exhaust gas air-cooled cooler 1. The ammonia solution and compressed air delivered by the ammonia supply pump are atomized in the ammonia spray gun and then sprayed into the inlet flue of the SCR reactor. After being fully mixed with the exhaust gas from the catalytic oxidation, it enters the SCR reactor for denitrification reaction. The reaction bed temperature is controlled at about 350°C to convert nitrogen oxides in the exhaust gas. After the purified exhaust gas is heat exchanged with the initial exhaust gas through the exhaust heat exchanger, it is cooled by the air-cooled cooler and then discharged into the atmosphere. The exhaust gas temperature is about 150°C.

[0033] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. An acrylonitrile tail gas recovery system suitable for multi-tank storage, characterized in that: The system includes a dual-channel three-stage condensation adsorption device, a mixing tank, an exhaust gas heat exchanger, an electric heater, a catalytic oxidation reactor, an air-cooled cooler I and an SCR reactor connected in sequence; The dual-channel three-stage condensation adsorption device comprises a channel A three-stage condensing unit and a channel B three-stage condensing unit arranged in parallel, and an adsorption tank connected to the channel A three-stage condensing unit and the channel B three-stage condensing unit connected in parallel; the channel A three-stage condensing unit and the channel B three-stage condensing unit are each provided with a first-stage cold box, a second-stage cold box and a third-stage cold box connected in sequence, the first-stage cold box, the second-stage cold box and the third-stage cold box are connected in pairs, the first-stage cold box of the channel A three-stage condensing unit and the channel B three-stage condensing unit is connected to the acrylonitrile tail gas recovery pipeline manifold of multiple tank areas through a tee, the third-stage cold box of the channel A three-stage condensing unit and the channel B three-stage condensing unit is connected to the input end of the adsorption tank through a tee I, and the output end of the adsorption tank is connected to the mixing tank; The exhaust gas heat exchanger includes a shell and a heat exchange pipe for passing purified exhaust gas. The heat exchange pipe is installed in the shell. The shell is provided with an initial exhaust gas inlet connected to a mixing tank and an initial exhaust gas outlet connected to an electric heater. One end of the heat exchange pipe is provided with a purified exhaust gas outlet connected to an SCR reactor, and the other end of the heat exchange pipe is provided with a purified exhaust gas inlet connected to an air-cooled cooler II.

2. The acrylonitrile tail gas recovery system suitable for multi-tank storage according to claim 1, characterized in that: The adsorption tank is provided with a tank body, an air inlet is provided at the bottom of the tank body, an air outlet is provided at the top of the tank body, at least two layers of composite adsorbent adsorption components are installed in the tank body, and gas buffer chambers are provided above and below each layer of composite adsorbent adsorption components. A vacuum analysis pipeline is connected to the air inlet through a tee II, and the vacuum analysis pipeline is respectively connected to the inlet end of the vacuum pump and the dual-channel three-stage condensation adsorption device through a tee III.

3. The acrylonitrile tail gas recovery system suitable for multi-tank storage according to claim 2, characterized in that: The composite adsorbent adsorption assembly includes a lower supporting mesh frame, a columnar composite adsorbent and an upper pressing plate. The lower supporting mesh frame is fixedly connected to a fixing ring arranged on the inner wall of the tank body. The columnar composite adsorbent is placed in the lower supporting mesh frame. The pressing plate covers the columnar composite adsorbent and is provided with a plurality of ventilation holes.

4. The acrylonitrile tail gas recovery system suitable for multi-tank storage according to claim 1, characterized in that: An ammonia spray gun for spraying ammonia solution into the SCR reactor is installed at the inlet of the SCR reactor, and the ammonia spray gun is connected to an ammonia metering pump through a gas-liquid mixer.

5. The acrylonitrile tail gas recovery system suitable for multi-tank storage according to claim 1, characterized in that: There are at least two adsorption tanks, which are arranged in parallel.

6. The acrylonitrile tail gas recovery system suitable for multi-tank storage according to claim 1, characterized in that: The purified tail gas outlet of the heat exchange pipeline is connected with an air-cooled cooler II and an exhaust pipe in sequence, and the air-cooled cooler II is connected with the exhaust pipe through a fan.

Images