Tail gas self-circulation white feather eliminating device

Abstract

The utility model relates to a tail gas self-circulation white feather eliminating device, which solves the problems of poor white feather eliminating effect and high cost of the existing industrial tail gas. Comprising a quench tower, an absorption tower, a gas-gas heat exchanger, an electric precipitator and a tail gas suction fan, during use, dry high-temperature tail gas enters a heat exchange pipe in the gas-gas heat exchanger for indirect heat exchange, and the tail gas subjected to heat exchange enters the quench tower and is in countercurrent contact with quench water from the quench tower; the washed and condensed tail gas is discharged to the lower part of the absorption tower from the top of the quench tower under the action of the circulating fan, and the dried tail gas enters the electrostatic dust collector to be purified after being absorbed and filtered by the absorption filtering device from the absorption circulating pump, and then enters the shell of the gas-gas heat exchanger to be subjected to indirect heat exchange; the purified tail gas is heated by the unpurified tail gas and then is discharged into the environment, namely the tail gas is heated to an unsaturated state by the heat of the tail gas, so that the aim of eliminating white feather of the tail gas is fulfilled, and the production cost is low.

Description

Technical Field

[0001] The utility model relates to the field of industrial tail gas treatment, in particular to a tail gas self-circulation white plume elimination device. Background Art

[0002] "White plume" is also known as "white smoke plume". During industrial production, the exhaust gas discharged from the chimney mixes with the ambient cold air. During the cooling process, the water vapor contained in the exhaust gas condenses to saturation. The water mist produced by condensation appears white feather-like under the refraction and scattering of light, thus being called "white plume".

[0003] In existing petrochemical and chemical production processes, over 80% require the use of catalysts. Catalyst preparation primarily involves five steps: colloid synthesis, spray drying, high-temperature calcination, filtration and water washing, and pneumatic drying. Each of these processes generates a certain amount of hot, dusty gas, which must be purified and absorbed before being discharged into the atmosphere. The exhaust gas from the spray drying process (150-180°C) and the pneumatic drying process (140-150°C) has high flow rates, high dust content, and the most severe tailing phenomenon, making effective solutions to this problem extremely urgent. Currently, treatment methods for dry exhaust gas, both domestically and internationally, primarily include scrubbing and a combination of scrubbing and electrostatic precipitators. After scrubbing and dust removal, the temperature of the dry exhaust gas is reduced to approximately 40-50°C before discharge into the atmosphere. Because the dry exhaust gas is saturated upon discharge into the atmosphere, when ambient temperatures are low, the water vapor in the exhaust gas rapidly condenses into small droplets, creating a "white smoke zone" (commonly known as "white plume") above the exhaust outlet. Compared with the single washing technology, the combination of washing + electrostatic precipitator technology has better dust removal and demisting effects, reducing the moisture content of the exhaust gas. However, in areas with cold climatic conditions, especially in winter, the "white feather" phenomenon still exists.

[0004] Currently, many countries, including foreign countries, are using electrostatic precipitator (ESP) demisting technology, which has been widely used in industries such as chemical engineering, metallurgy, and atmospheric treatment. Although this technology has a good demisting effect, it still cannot achieve the goal of eliminating "white plume". At the same time, this technology has disadvantages such as high investment and high production costs. Utility Model Content

[0005] The utility model aims to solve the problem that the existing industrial tail gas "white plume" elimination effect is poor and the cost is high.

[0006] The technical solution adopted to solve the technical problem proposed by the utility model is:

[0007] The exhaust gas self-circulation and white plume elimination device for feeding tail gas of the utility model comprises a quenching tower and an absorption tower, the quenching tower is provided with a quenching and cooling device, the absorption tower is provided with an absorption and filtering device, the white plume elimination device also comprises an air-to-air heat exchanger, an electrostatic precipitator and an exhaust gas suction fan, the air-to-air heat exchanger comprises a sealed heat exchanger shell and a heat exchange pipe arranged in the heat exchanger shell, the air inlet end of the heat exchange pipe is connected with the exhaust gas exhaust port, the air outlet end of the heat exchange pipe is connected with the air inlet of the quenching tower, a quenching water nozzle is provided in the quenching tower, the quenching water nozzle is arranged above the air inlet of the emergency cooling tower, a circulating fan is provided between the air outlet of the quenching tower and the air inlet of the absorption tower, the air outlet of the absorption tower is connected with the air inlet of the electrostatic precipitator, the air outlet of the electrostatic precipitator is connected with the air inlet of the exhaust gas suction fan, a circulating air inlet connected with the air outlet of the exhaust gas suction fan is provided on the heat exchanger shell, and an external exhaust gas outlet is also provided on the heat exchanger shell.

[0008] The technical solutions that further define the utility model include:

[0009] The white feather removal device also includes a quenching tower circulation pump. A quenching tower water tank is provided at the bottom of the quenching tower. The water inlet of the quenching tower circulation pump is connected to the bottom of the quenching tower water tank, and the water outlet of the quenching tower circulation pump is connected to the quenching water nozzle.

[0010] The water outlet of the quenching tower circulation pump is connected to the quenching tower sewage outlet.

[0011] The rapid cooling device is a water-cooling ring pipe arranged in the shell wall of the rapid cooling tower.

[0012] The quenching water nozzle is a Venturi structure nozzle.

[0013] The white feather elimination device also includes an absorption tower circulation pump. The absorption and filtration device is arranged at the upper part of the absorption tower. The absorption and filtration device includes a packing layer, a spray pipe and a demister. The spray pipe is arranged above the corresponding packing layer. The demister is arranged at the top of the absorption tower. The bottom of the absorption tower is provided with an absorption tower water tank. The water inlet of the absorption tower circulation pump is connected to the bottom of the absorption tower water tank, and the water outlet of the absorption tower circulation pump is connected to the spray pipe.

[0014] The demister is a mesh cover arranged on the top of the absorption tower, and the air outlet of the absorption tower is arranged above the mesh cover.

[0015] The water outlet of the absorption tower circulation pump is connected to the absorption tower sewage outlet.

[0016] Through the above technical scheme, the beneficial effects of the utility model are as follows: when the tail gas self-circulation white plume elimination device of the utility model is used, the dry high-temperature tail gas enters the heat exchange tube in the gas-to-gas heat exchanger for indirect heat exchange, and the tail gas after heat exchange enters the quenching tower and is countercurrently contacted with the quenching water from the quenching tower. Part of the dust and water vapor carried in the tail gas is washed and condensed, and a small part of the gas dissolved in water is absorbed. The tail gas after washing and condensation is discharged from the top of the quenching tower to the lower part of the absorption tower under the action of the circulating fan, and the dry tail gas and the tail gas from the absorption circulation pump are absorbed through the absorption After absorption and filtration by the filter device, the harmful gases carried in the dry exhaust gas are absorbed. The dry exhaust gas after absorption treatment then enters the electrostatic precipitator to further remove solid particles and other substances therein; the dry exhaust gas after electrostatic dust removal enters the shell of the gas-to-gas heat exchanger under the action of the exhaust gas suction fan, and the purified exhaust gas exchanges heat with the unpurified exhaust gas in the heat exchange tube. The purified exhaust gas is heated by the unpurified exhaust gas and then discharged into the environment, that is, the exhaust gas is heated to a non-saturated state using its own heat, thereby achieving the purpose of exhaust gas white plume removal, thereby low production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a side structural diagram of a tail gas self-circulating white plume elimination device of the utility model. DETAILED DESCRIPTION

[0018] The structure of the present invention is further described below with reference to the accompanying drawings.

[0019] Reference Figure 1 This example illustrates the method for eliminating tail gas plume from the catalyst preparation industry. However, the method is not limited to this industry and can also be applied to other industrial sectors, such as petrochemicals, chemicals, metallurgy, and coal chemical industries. In this example, the dry tail gas from the catalyst preparation industry is primarily composed of nitrogen, oxygen, carbon dioxide, water vapor, and small amounts of dust and hydrogen chloride, with a temperature of 150-180°C.

[0020] A tail gas self-circulation white plume elimination device includes a quenching tower 1 and an absorption tower 2. The quenching tower is provided with a quenching and cooling device. The absorption tower 2 is provided with an absorption and filtering device 21. The white plume elimination device also includes an air-to-air heat exchanger 3, an electrostatic precipitator 4 and an exhaust gas suction fan 5. The air-to-air heat exchanger 3 includes a sealed heat exchanger shell 31 and a heat exchange tube 32 provided in the heat exchanger shell. The air inlet end 321 of the heat exchange tube is connected to the tail gas outlet, and the air outlet end 322 of the heat exchange tube is connected to the air inlet of the quenching tower. The air-to-air heat exchanger can adopt different types such as shell and tube heat exchanger and fin tube heat exchanger. The unpurified tail gas is introduced into the heat exchange tube of the air-to-air heat exchanger. The high-temperature gas in the tube exchanges heat with the purified gas in the heat exchanger shell outside the heat exchange tube through the heat exchange tube, thereby heating the purified gas in the heat exchanger shell, thereby heating by its own heat, saving costs. The quenching tower 1 is equipped with a quenching water nozzle 11, positioned above the emergency cooling tower's air inlet 12. The quenching water sprayed from the quenching water nozzle cools and washes the exhaust gas, condensing some of the dust and water vapor carried in the exhaust gas. In this embodiment, the white plume removal device also includes a quenching tower circulation pump 6. A quenching tower water tank 13 is provided at the bottom of the quenching tower 1. A water inlet can be provided above the quenching tower water tank to discharge water into the quenching tower water tank. The quenching tower circulation pump's water inlet 61 is connected to the bottom of the quenching tower water tank, and its water outlet 62 is connected to the quenching water nozzle. The quenching and cooling device comprises a water-cooling loop pipe located within the quenching tower shell. Circulating quenching water within the water-cooling loop rapidly cools the quenching tower shell. The quenching tower shell can be made of fiberglass, and the water-cooling loop pipe and quenching water nozzle can be made of polytetrafluoroethylene to prevent corrosion from acidic and alkaline substances. The quench tower circulation pump pumps water from the water tank to the quench water nozzle for spraying. The water falls into the quench tower water tank and is then recycled by the quench tower circulation pump, conserving resources. The quench tower circulation pump's water outlet 62 is connected to the quench tower drain outlet 63. When wastewater needs to be removed, the quench water nozzle is closed, and the quench tower circulation pump drains the wastewater out of the quench tower drain outlet. In this embodiment, the quench water nozzle is a Venturi-type nozzle. This increases the pressure of the quench water spray, thereby rapidly cooling the exhaust gas.

[0021] A circulating fan 7 is provided between the quench tower's air outlet 13 and the absorption tower's air inlet 22. The circulating fan draws the cooled and purified gas from the quench tower into the absorption tower. In this embodiment, the absorption tower is primarily used to absorb hydrogen chloride gas dissolved in water. In specific implementations, different absorption and filtration devices can be installed as needed to provide targeted absorption and purification.

[0022] In this embodiment, the white plume elimination device also includes an absorption tower circulation pump 8. An absorption and filtration device is located at the top of the absorption tower. The absorption and filtration device 21 includes a packing layer, a spray pipe, and a demister. The spray pipe is located above the packing layer. The demister is located at the top of the absorption tower. The bottom of the absorption tower 2 is provided with an absorption tower water tank 23. The water inlet 81 of the absorption tower circulation pump is connected to the bottom of the absorption tower water tank, and the water outlet 82 of the absorption tower circulation pump is connected to the spray pipe. The absorption tower circulation pump pumps water from the absorption tower water tank to the spray pipe for spraying. The spray pipe wets the packing layer. The wetted packing layer absorbs hydrogen chloride in the tail gas and further filters the tail gas. The spray water falls into the absorption tower water tank and is recycled by the absorption tower circulation pump, saving resources. In this embodiment, the water outlet of the absorption tower circulation pump 8 is connected to the absorption tower sewage outlet 83. When sewage needs to be discharged, the spray pipe is closed and the sewage is discharged from the absorption tower sewage outlet through the absorption tower circulation pump. In this embodiment, the demister is a mesh cover installed at the top of the absorption tower, with the tower outlet positioned above the mesh cover. The mesh cover traps and deflects droplets in the exhaust gas, further purifying it. The absorption tower shell can be made of fiberglass, and the packing layer, spray pipe, and mesh cover can all be made of polytetrafluoroethylene to prevent corrosion from acidic and alkaline substances.

[0023] The air outlet 24 of the absorption tower is connected to the air inlet of the electrostatic precipitator 4. When the exhaust gas enters the electrostatic precipitator, the exhaust gas is ionized by the high-voltage electric field, causing the dust particles to be charged. The electric field force causes the dust particles to be deposited on the dust accumulator, thereby further removing fine dust particles from the exhaust gas. The air outlet of the electrostatic precipitator is connected to the air inlet of the exhaust gas suction fan 5. The heat exchanger housing 31 is provided with a circulating air inlet 311 connected to the air outlet of the exhaust gas suction fan. The heat exchanger housing is also provided with an external exhaust gas outlet 312. The exhaust gas suction fan draws the purified exhaust gas into the heat exchanger housing. The high-temperature, unpurified exhaust gas in the heat exchange tubes of the gas-to-gas heat exchanger heats the purified gas in the heat exchanger housing, thereby heating the heat exchanger housing through its own heat.

[0024] The method for eliminating white plume by self-circulating exhaust gas using the exhaust gas self-circulating white plume elimination device of the utility model comprises the following steps:

[0025] Step A: The dry high-temperature exhaust gas, which mainly consists of nitrogen, oxygen, carbon dioxide, water vapor and a small amount of dust, hydrogen chloride, etc., has a temperature of 150-180°C. The dry high-temperature exhaust gas enters the heat exchange tube in the air-to-air heat exchanger for indirect heat exchange. The heat exchange tube passes through the shell of the air-to-air heat exchanger, and the heat exchange tube and the shell of the air-to-air heat exchanger form an independent sealed space; the exhaust gas in the heat exchange tube is cooled to 110-130 degrees after heat exchange.

[0026] Step B: The tail gas after heat exchange enters the quenching tower. The quenching tower circulation pump draws the quenching water in the quenching tower water tank to the quenching water nozzle for spraying. The tail gas is in countercurrent contact with the quenching water from the quenching tower. Part of the dust and water vapor carried in the tail gas is washed and condensed, and a small amount of water-soluble gas is absorbed. The tail gas after washing and condensation is about 40~50℃; when sewage needs to be discharged, the quenching water nozzle is closed, and the quenching tower circulation pump discharges the sewage through the quenching tower sewage outlet connected to the quenching tower circulation pump.

[0027] Step C: The tail gas after washing and condensation is discharged from the top of the quenching tower to the lower part of the absorption tower under the action of the circulating fan. The dry tail gas and the air from the absorption circulation pump are absorbed and filtered by the absorption filter device, and the harmful gases carried in the dry tail gas are absorbed. During specific implementation, different absorption filter devices are set according to the harmful gases that need to be absorbed. In this embodiment, an absorption tower water tank is provided at the bottom of the absorption tower. The absorption filter device includes a packing layer, a spray pipe and a demister. The absorption tower circulation pump draws water from the absorption tower water tank to the spray pipe and sprays it onto the packing layer. The dry tail gas contacts the packing layer after spraying. The hydrogen chloride gas dissolved in water in the dry tail gas is absorbed by the packing layer and then passes through the demister. The demister deflects the droplets in the tail gas. When sewage needs to be discharged, the spray pipe is closed, and the absorption tower circulation pump discharges the sewage through the absorption tower sewage outlet connected to the absorption tower circulation pump.

[0028] Step D: The dry exhaust gas after absorption treatment then enters the electrostatic precipitator to further remove solid particles and other substances therein; the exhaust gas is ionized by the high-voltage electric field in the electrostatic precipitator, which charges the dust particles and deposits them on the dust accumulator under the action of the electric field force, thereby further removing fine dust particles in the exhaust gas.

[0029] Step F: After electrostatic dust removal, the dried exhaust gas enters the shell of the air-to-air heat exchanger under the action of the exhaust gas suction fan. The purified exhaust gas exchanges heat with the unpurified exhaust gas in the heat exchange tube. The purified exhaust gas is heated to 60-80°C by the unpurified exhaust gas before being discharged into the environment. This utilizes the exhaust gas's own heat to heat the exhaust gas to a non-saturated state, achieving the purpose of exhaust plume removal and reducing production costs.

[0030] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0031] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0032] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection, or communication; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0033] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0034] Although the specific embodiments of the present invention are described in detail in conjunction with the accompanying drawings, this should not be construed as limiting the scope of protection of the present invention. Within the scope described by the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of the present invention.

Claims

1. A tail gas self-circulating white plume removal device, comprising a quenching tower and an absorption tower, wherein the quenching tower is provided with a quenching and cooling device, and the absorption tower is provided with an absorption and filtering device, characterized in that: The white plume elimination device also includes an air-to-air heat exchanger, an electrostatic precipitator and an exhaust gas suction fan. The air-to-air heat exchanger includes a sealed heat exchanger shell and a heat exchange tube arranged in the heat exchanger shell. The air inlet end of the heat exchange tube is connected to the exhaust gas outlet, and the air outlet end of the heat exchange tube is connected to the air inlet of the quenching tower. A quenching water nozzle is provided in the quenching tower, and the quenching water nozzle is arranged above the air inlet of the emergency cooling tower. A circulating fan is provided between the air outlet of the quenching tower and the air inlet of the absorption tower. The air outlet of the absorption tower is connected to the air inlet of the electrostatic precipitator, and the air outlet of the electrostatic precipitator is connected to the air inlet of the exhaust gas suction fan. A circulating air inlet connected to the air outlet of the exhaust gas suction fan is provided on the heat exchanger shell, and an external exhaust gas outlet is also provided on the heat exchanger shell.

2. The exhaust gas self-circulation white plume elimination device according to claim 1, characterized in that: The white feather removal device also includes a quenching tower circulation pump. A quenching tower water tank is provided at the bottom of the quenching tower. The water inlet of the quenching tower circulation pump is connected to the bottom of the quenching tower water tank, and the water outlet of the quenching tower circulation pump is connected to the quenching water nozzle.

3. The exhaust gas self-circulation white plume elimination device according to claim 2, characterized in that: The water outlet of the quenching tower circulation pump is connected to the quenching tower sewage outlet.

4. The exhaust gas self-circulation white plume elimination device according to claim 2, characterized in that: The rapid cooling device is a water-cooling ring pipe arranged in the shell wall of the rapid cooling tower.

5. The exhaust gas self-circulating white plume elimination device according to claim 2, characterized in that: The quenching water nozzle is a Venturi structure nozzle.

6. The exhaust gas self-circulating white plume elimination device according to claim 1, characterized in that: The white feather elimination device also includes an absorption tower circulation pump. The absorption and filtration device is arranged at the upper part of the absorption tower. The absorption and filtration device includes a packing layer, a spray pipe and a demister. The spray pipe is arranged above the corresponding packing layer. The demister is arranged at the top of the absorption tower. The bottom of the absorption tower is provided with an absorption tower water tank. The water inlet of the absorption tower circulation pump is connected to the bottom of the absorption tower water tank, and the water outlet of the absorption tower circulation pump is connected to the spray pipe.

7. The exhaust gas self-circulating white plume elimination device according to claim 6, characterized in that: The demister is a mesh cover arranged on the top of the absorption tower, and the air outlet of the absorption tower is arranged above the mesh cover.

8. The exhaust gas self-circulating white plume elimination device according to claim 6, characterized in that: The water outlet of the absorption tower circulation pump is connected to the absorption tower sewage outlet.

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