Tail gas absorption and purification device for p-chlorobenzotrifluoride synthesis

Abstract

The invention belongs to the technical field of tail gas absorption treatment, and particularly relates to a tail gas absorption and purification device for p-chlorobenzotrifluoride synthesis, which comprises an absorption tank, and the absorption tank is provided with a liquid outlet pipe, a gas inlet pipe, a liquid inlet pipe and a gas outlet pipe from bottom to top; a distribution ring and a spray head are mounted at the upper end in the absorption tank, and the liquid inlet pipe is communicated with the distribution ring; a communicating ring and a gas distribution pipe are mounted at the lower end in the absorption tank, and the gas inlet pipe is communicated with the communicating ring; a spraying channel is formed in the gas distribution pipe, a liquid suction pipe is mounted on the gas distribution pipe, and the liquid suction pipe and the gas distribution pipe are located below the liquid level of the treatment liquid; the tail gas and the treatment liquid are in mutual contact for multiple times, the states of the tail gas and the treatment liquid are changed during contact, the contact area and the contact time of the tail gas and the treatment liquid are increased, the tail gas absorption treatment effect and efficiency are improved, meanwhile, the treatment liquid gathered at the bottom in the tank body is recycled, and the utilization rate of the treatment liquid is increased as much as possible.

Description

Technical Field

[0001] The invention belongs to the technical field of tail gas absorption and treatment, in particular to a tail gas absorption and purification device for the synthesis of para-chlorobenzotrifluoride. Background Art

[0002] Parachlorobenzotrifluoride, also known as parachlorotrifluoromethylbenzene, 4-chlorobenzotrifluoride, parachlorobenzyltrifluoride, and parachlorobenzyltrifluoride, is a colorless, transparent liquid insoluble in water but soluble in organic solvents such as alcohol, ether, and benzene. Parachlorobenzotrifluoride is a flammable and toxic chemical that is irritating to the skin and eyes. It can burn and emit toxic gases when exposed to open flames, high temperatures, or contact with oxidants. Parachlorobenzotrifluoride can be used as an intermediate in the synthesis of pharmaceuticals, including anti-tumor, anti-psychotic, anti-Alzheimer's, sedatives, and diuretics.

[0003] The production process of parachlorobenzotrifluoride produces a large amount of waste gas such as hydrogen fluoride gas, hydrogen chloride gas and chlorine gas. These waste gases are easy to pollute the environment and cause harm to the human body. Therefore, before the exhaust gas is discharged, the toxic and harmful gases need to be absorbed and removed to avoid polluting the environment and causing harm to people. Summary of the Invention

[0004] In order to overcome the shortcomings of the existing technology, the present invention proposes a tail gas absorption and purification device for the synthesis of para-chlorotrifluorotoluene, which allows the tail gas and the treatment liquid to contact each other multiple times and changes the state of the two during contact, thereby increasing the contact area and contact time between the tail gas and the treatment liquid, improving the effect and efficiency of the tail gas absorption treatment, and at the same time, reusing the treatment liquid collected at the bottom of the tank body to maximize the utilization rate of the treatment liquid.

[0005] The technical solution adopted by the present invention to solve the technical problem is as follows: the tail gas absorption and purification device for the synthesis of para-chlorobenzotrifluoride comprises an absorption tank, wherein the absorption tank is equipped with a liquid outlet pipe, an air inlet pipe, a liquid inlet pipe, and an air outlet pipe from bottom to top, the absorption tank comprises a hydrogen fluoride absorption tank and a hydrogen chloride absorption tank, the air outlet pipe on the hydrogen fluoride absorption tank is connected to the air inlet pipe on the hydrogen chloride absorption tank through a connecting pipe, and the lower part of the absorption tank is filled with a treatment liquid;

[0006] A distribution ring is installed at the upper end of the absorption tank, a nozzle is installed on the distribution ring, the liquid inlet pipe is connected to the distribution ring, and the distribution ring is located above the liquid level of the treatment liquid;

[0007] A connecting ring is installed at the lower end of the absorption tank, an air distribution pipe is installed on the connecting ring, the air inlet pipe and the connecting ring are connected to each other, and the air distribution pipe is located below the liquid level of the treatment liquid;

[0008] An ejection channel is provided in the air distribution pipe, and the shape of the ejection channel is a gradually expanding trumpet shape. A liquid suction pipe is installed on the air distribution pipe, and the liquid suction pipe is connected to one end of the ejection channel close to the connecting ring.

[0009] Preferably, an air outlet bag is installed on the air distribution pipe, and the air outlet bag is located below the liquid level of the treatment liquid;

[0010] The air outlet bag is made of corrosion-resistant plastic net, and the air outlet bag is formed by overlapping multiple layers of plastic nets.

[0011] Preferably, an enlarged mounting plate is installed at the outlet of the air distribution pipe through a thread, the air outlet bag is installed on the enlarged mounting plate, and the air outlet bag in the tank body opens toward the bottom surface of the tank body.

[0012] Preferably, there is relative movement between the layers of plastic nets in the air outlet bag.

[0013] Preferably, a telescopic hose is installed on the liquid suction pipe, an inverted U-shaped tube is installed on the telescopic hose, a floating block is installed on the U-shaped tube, and the inlet of the U-shaped tube is immersed in the treatment liquid.

[0014] Preferably, a mounting frame is installed in the tank body, the mounting frame is located above the air outlet bag, a fixing rod is installed on the mounting frame, a spiral plate is rotatably installed on the fixing rod, and the spiral plate is located below the liquid surface of the treatment liquid.

[0015] Preferably, a plurality of spiral plates are mounted on the fixing rod, and the spiral directions of adjacent spiral plates on the fixing rod are opposite;

[0016] The number of turns of the upper spiral plate on the fixed rod is less than the number of turns of the lower spiral plate, the pitch of the upper spiral plate on the fixed rod is greater than the pitch of the lower spiral plate, the spiral plates do not contact each other, and the pipette does not contact the spiral plates.

[0017] Preferably, the mesh sizes of adjacent plastic nets in the air outlet bag are not limited to the same.

[0018] The beneficial effects of the present invention are as follows:

[0019] 1. The tail gas absorption and purification device for the synthesis of parachlorotrifluorotoluene described in the present invention is provided with a distribution ring, a nozzle, a connecting ring, an air distribution pipe, and a liquid suction pipe, so that the tail gas is sprayed from the air distribution pipe and forms bubbles in the treatment liquid, so that the tail gas in the bubbles is fully contacted with the treatment liquid. At the same time, the drops of treatment liquid sprayed from the nozzle fall in the tank body and fully contact with the rising tail gas. At the same time, the liquid suction pipe sucks the treatment liquid into the air distribution pipe, and the treatment liquid is impacted and dispersed by the high-speed gas to form droplets that contact the tail gas. As a result, the tail gas and the treatment liquid in the absorption tank are in contact multiple times, and the state of the two changes during each contact, thereby increasing the contact area and contact time between the tail gas and the treatment liquid, and improving the effect and efficiency of the tail gas absorption treatment. At the same time, because the fallen treatment liquid is accumulated at the bottom of the tank body and the air distribution pipe releases bubbles in the treatment liquid, the absorption medium in the fallen treatment liquid is continuously utilized, thereby improving the utilization rate of the treatment liquid and reducing the burden on the nozzle.

[0020] 2. The tail gas absorption and purification device for the synthesis of parachlorotrifluorotoluene described in the present invention is provided with an air distribution pipe and an air outlet bag, so that the tail gas discharged from the air distribution pipe fills and supports the air outlet bag, so that the tail gas is discharged from the micropores on the air outlet bag, forming a large number of bubbles of the tail gas, and increasing the area where the bubbles are released and rise, so that the bubbles are fully in contact with the treatment liquid, avoiding an excessive number of bubbles in the treatment liquid in a local area, making the concentration of the absorption medium in the treatment liquid too low, and affecting the tail gas absorption treatment effect.

[0021] 3. The tail gas absorption and purification device for the synthesis of parachlorotrifluorotoluene described in the present invention guides and directs the rising bubbles in the treatment liquid by providing a mounting frame, a fixing rod and a spiral plate, thereby extending the residence time of the bubbles in the treatment liquid and improving the treatment effect of the treatment liquid on the tail gas. At the same time, the rising bubbles will push the spiral plate, and then the spiral plate will stir and push the treatment liquid, so that the treatment liquid is evenly distributed, further improving the treatment effect and efficiency of the tail gas absorption. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below with reference to the accompanying drawings.

[0023] Figure 1 It is a three-dimensional diagram of the tail gas absorption and purification device of the present invention;

[0024] Figure 2 It is a schematic structural diagram of the absorption tank in the tail gas absorption and purification device of the present invention;

[0025] Figure 3 This is a schematic structural diagram of the liquid inlet pipe, distribution ring and nozzle in the absorption tank of the present invention;

[0026] Figure 4It is a structural schematic diagram of the mounting frame and the spiral plate in the absorption tank of the present invention;

[0027] Figure 5 This is a schematic diagram of the installation of the air distribution pipe, air outlet bag and liquid suction pipe in the absorption tank of the present invention;

[0028] Figure 6 This is a schematic diagram of the structure of the air distribution pipe and the liquid suction pipe in the absorption tank of the present invention;

[0029] Figure 7 It is a schematic diagram of the structure of the gas outlet bag in the absorption tank of the present invention;

[0030] In the figure: hydrogen fluoride absorption tank 1, hydrogen chloride absorption tank 11, connecting pipe 12, tank body 2, liquid outlet pipe 21, liquid inlet pipe 22, distribution ring 221, nozzle 222, air inlet pipe 23, air outlet pipe 24, spiral plate 3, mounting frame 31, fixing rod 32, air distribution pipe 4, connecting ring 41, air outlet bag 42, expanded mounting plate 421, liquid suction pipe 43, telescopic hose 431, U-shaped tube 432, floating block 433. DETAILED DESCRIPTION

[0031] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0032] like Figures 1 to 7 As shown, the tail gas absorption and purification device for the synthesis of para-chlorobenzotrifluoride according to the present invention includes an absorption tank, which is equipped with a liquid outlet pipe 21, an air inlet pipe 23, a liquid inlet pipe 22, and an air outlet pipe 24 from bottom to top. The absorption tank includes a hydrogen fluoride absorption tank 1 and a hydrogen chloride absorption tank 11. The air outlet pipe 24 on the hydrogen fluoride absorption tank 1 is connected to the air inlet pipe 23 on the hydrogen chloride absorption tank 11 through a connecting pipe 12. The lower part of the absorption tank is filled with a treatment liquid.

[0033] A distribution ring 221 is installed at the upper end of the absorption tank, a nozzle 222 is installed on the distribution ring 221, the liquid inlet pipe 22 and the distribution ring 221 are connected to each other, and the distribution ring 221 is located above the liquid level of the treatment liquid;

[0034] A connecting ring 41 is installed at the lower end of the absorption tank, and an air distribution pipe 4 is installed on the connecting ring 41. The air inlet pipe 23 is connected to the connecting ring 41, and the air distribution pipe 4 is located below the liquid level of the treatment liquid.

[0035] The air distribution pipe 4 is provided with an ejection channel in the shape of a gradually expanding trumpet. A liquid suction pipe 43 is installed on the air distribution pipe 4 and is connected to one end of the ejection channel near the connecting ring.

[0036] During operation, the tail gas generated during the synthesis of parachlorobenzotrifluoride is sequentially introduced into the hydrogen fluoride absorption tank 1 and the hydrogen chloride absorption tank 11, so that the hydrogen fluoride gas, hydrogen chloride gas and chlorine gas in the tail gas are absorbed and treated, ensuring that the tail gas discharged after treatment is non-toxic and harmless, avoiding harm to the environment and personnel. At the same time, a hydrogen fluoride treatment liquid is used in the hydrogen fluoride absorption tank 1, and an alkaline solution is used in the hydrogen chloride absorption tank 11. By using different treatment liquids, the effect of tail gas absorption treatment is improved;

[0037] At the same time, during the treatment process, the exhaust gas enters the tank body 2 of the absorption tank from the air inlet pipe 23, and then enters the connecting ring 41 and is discharged into the tank body 2 from the air distribution pipe 4 on the connecting ring 41. At the same time, since the lower part of the absorption tank is accumulated with treatment liquid and the air distribution pipe 4 is immersed in the treatment liquid, the exhaust gas discharged from the air distribution pipe 4 enters the treatment liquid and forms bubbles containing exhaust gas, so that the exhaust gas and the treatment liquid are fully in contact, thereby improving the exhaust gas absorption and treatment effect. At the same time, the exhaust gas discharged from the air distribution pipe 4 will pass through the treatment liquid layer at the lower part of the tank body 2 from bottom to top, and then the exhaust gas will continue to move upward until the exhaust gas is discharged from the tank body 2 from the air outlet pipe 24.

[0038] At the same time, during the exhaust gas treatment process, the treatment liquid is fed into the tank body 2 from the liquid inlet pipe 22, and then the treatment liquid is sprayed out from the distribution ring 221 and the nozzle 222 above the tank body 2, forming tiny treatment liquid droplets in the tank body 2 until the droplets contact and converge into the treatment liquid layer at the bottom of the tank body 2. Afterwards, in conjunction with the exhaust gas discharged from the gas distribution pipe 4 and moving upward, the exhaust gas and the droplets will have a secondary contact, further increasing the contact time and contact sufficiency between the exhaust gas and the treatment liquid, thereby improving the absorption efficiency and absorption effect of the exhaust gas treatment. At the same time, the treatment liquid layer accumulated in the lower part of the tank body 2 is discharged to the outside of the tank body 2 through the liquid outlet pipe 21, so as to circulate and replace the treatment liquid, ensure that the treatment effect of the treatment liquid on the exhaust gas is good, and remove impurities accumulated in the treatment liquid. At the same time, the discharge of the treatment liquid in the tank body 2 through the liquid outlet pipe 21 ensures that the height of the treatment liquid accumulated in the tank body 2 is relatively stable, avoiding too much or too little treatment liquid accumulating at the bottom of the tank body 2, affecting the normal operation of the device.

[0039] At the same time, since the air distribution pipe 4 is provided with an ejection channel and the shape of the ejection channel is a gradually expanding trumpet shape, the air distribution pipe 4 has the same effect as the Laval nozzle, so that the exhaust gas ejected from the air distribution pipe 4 has a relatively fast speed, and the gas flow rate ejected from the air distribution pipe 4 into the treatment liquid layer is faster, which makes it easier to disperse the treatment liquid and the exhaust gas, and to generate smaller bubbles in the treatment liquid, thereby increasing the contact area between the exhaust gas and the treatment liquid and improving the exhaust gas absorption and treatment effect. At the same time, since the suction pipe 43 is installed on the air distribution pipe 4 and there is fast-flowing exhaust gas in the air distribution pipe 4, according to the Bernoulli principle, the treatment liquid in the tank body 2 will be sucked into the air distribution pipe 4, and the sucked treatment liquid will be impacted and dispersed into tiny droplets, so that the treatment liquid and the exhaust gas begin to make initial contact in the air distribution pipe 4, that is, the exhaust gas and the treatment liquid have a third contact, thereby increasing the contact area, contact time and contact sufficiency between the exhaust gas and the treatment liquid, and improving the absorption efficiency and absorption effect of the exhaust gas treatment.

[0040] At the same time, through multiple contacts between the exhaust gas and the treatment liquid, as well as changes in the state of the exhaust gas and the treatment liquid when they contact each other, such as treatment liquid droplets and exhaust gas, treatment liquid and exhaust gas bubbles, the exhaust gas and the treatment liquid are fully in contact and the contact time between the two is extended, thereby improving the efficiency and effect of exhaust gas treatment. At the same time, the treatment liquid layer that drips and accumulates in the lower part of the tank body 2 will further absorb and treat the exhaust gas, thereby maximizing the utilization rate of the absorption medium in the treatment liquid.

[0041] As an embodiment of the present invention, an air outlet bag 42 is installed on the air distribution pipe 4, and the air outlet bag 42 is located below the liquid surface of the treatment liquid;

[0042] The air outlet bag 42 is made of a corrosion-resistant plastic mesh, and the air outlet bag 42 is composed of multiple layers of plastic mesh stacked together;

[0043] Since the air outlet bag 42 is composed of multiple layers of plastic mesh stacked together, there are numerous micropores on the air outlet bag 42. Therefore, after the exhaust gas is ejected from the outlet of the air distribution pipe 4, the exhaust gas will fill the air outlet bag 42, causing the air outlet bag 42 to be propped up and bulged. Afterwards, the exhaust gas filling the air outlet bag 42 will be discharged from the micropores on the air outlet bag 42 and form tiny bubbles in the treatment liquid.

[0044] At the same time, since the surface area of the gas outlet bag 42 is relatively large and the micropores are evenly distributed on the gas outlet bag 42, the distribution range of the bubbles in the treatment liquid is increased, and the bubbles are distributed as evenly as possible, so that the exhaust gas in the bubbles can fully contact the absorption medium in the treatment liquid, thereby improving the effect and efficiency of the exhaust gas absorption treatment. This avoids the bubbles formed by the exhaust gas discharged from the gas distribution pipe 4 from being relatively concentrated, resulting in excessive consumption of the absorption medium in the treatment liquid in a local area, and further preventing the exhaust gas in the bubbles from fully contacting the absorption medium, thereby affecting the effect and efficiency of the exhaust gas absorption treatment.

[0045] At the same time, since the gas outlet bag 42 is made of a plastic mesh and is filled and supported by the exhaust gas discharged into the gas outlet bag 42, the appearance and shape of the gas outlet bag 42 are relatively unstable and will change with the fluctuation of the treatment liquid layer and the speed and amount of exhaust gas discharged from the micropores on the gas outlet bag 42. This causes the distribution position of the bubbles generated by the exhaust gas discharged from the micropores on the gas outlet bag 42 in the treatment liquid to change, and causes the bubbles generated in the gas outlet bag 42 to be distributed and move in a disordered manner, thereby increasing the stirring effect on the treatment liquid layer, promoting the uniform distribution of the absorption medium in the treatment liquid, and ensuring the absorption and treatment effect and efficiency of the exhaust gas.

[0046] At the same time, since the air outlet bag 42 is installed on the air distribution pipe 4, after the air outlet bag 42 is propped up by the exhaust gas, a relatively empty space is formed at the outlet of the air distribution pipe 4. At this time, the droplets sucked into the air distribution pipe 4 through the liquid suction pipe 43 and crushed by the high-speed airflow are mixed in the air distribution pipe 4 and discharged into the air outlet bag 42 to continue mixing and fully contacting with each other, thereby increasing the contact time and contact area between the droplets and the exhaust gas, and avoiding the situation where the sucked and atomized treatment liquid only contacts the exhaust gas in the air distribution pipe 4 and the contact time is too short, which affects the exhaust gas absorption and treatment effect.

[0047] At the same time, since the exhaust gas is filled into the air outlet bag 42 and the exhaust gas will be discharged from the micropores under the action of pressure, the treatment liquid droplets sucked and atomized by the high-speed airflow will also be discharged along with the discharge of the exhaust gas in the air outlet bag 42, and some droplets that are not discharged in time and are gathered and liquefied will also be discharged from the micropores into the external treatment liquid layer under the action of the relatively large pressure in the air outlet bag 42, thereby avoiding the gradual accumulation, aggregation and liquefaction of the atomized droplets in the air outlet bag 42, causing the air outlet bag 42 to be filled with treatment liquid, causing the air outlet bag 42 to lose its function.

[0048] As an embodiment of the present invention, an enlarged mounting plate 421 is threadedly mounted at the outlet of the air distribution pipe 4, and the air outlet bag 42 is mounted on the enlarged mounting plate 421. The opening of the air outlet bag 42 in the tank body 2 faces the bottom surface of the tank body 2.

[0049] Since the air outlet bag 42 is mounted on the enlarged mounting plate 421, and the enlarged mounting plate 421 is mounted on the air distribution pipe 4 by means of threads, when the air outlet bag 42 is aged or damaged, the staff can easily replace the air outlet bag 42, thereby facilitating the maintenance of the device and improving the maintenance efficiency of the device. At the same time, the air outlet bag 42 is invertedly mounted on the enlarged mounting plate 421 in the treatment liquid. After the exhaust gas is discharged from the air distribution pipe 4 into the air outlet bag 42, the air outlet bag 42 will intercept and block some of the particulate impurities remaining in the exhaust gas, thereby preventing the residual particulate impurities from entering the treatment liquid and affecting the normal use of the treatment liquid.

[0050] At the same time, after the particulate impurities remaining in the exhaust gas enter the air outlet bag 42, the particulate impurities are intercepted by the air outlet bag 42 and fall onto the expanded mounting plate 421, and then the particulate impurities are collected by the expanded mounting plate 421 to prevent the particulate impurities from falling onto the bottom surface of the air outlet bag 42, and to prevent the intercepted and fallen particulate impurities from entering the air distribution pipe 4, affecting the normal use of the air distribution pipe 4.

[0051] As an embodiment of the present invention, there is relative movement between the layers of plastic mesh in the air outlet bag 42;

[0052] Because the gas outlet bag 42 is made of multiple layers of plastic mesh stacked together, there is misalignment between the layers of plastic mesh on the gas outlet bag 42, and the mesh holes on the plastic mesh are also overlapped and cut, resulting in non-uniform size and shape of the micropores on the gas outlet bag 42. As the exhaust gas is discharged from the micropores on the gas outlet bag 42, the size and frequency of bubbles formed in the micropores will change, thereby improving the uniformity of the bubble distribution in the treatment liquid and increasing the contact area between the bubbles and the treatment liquid, thereby improving the exhaust gas absorption and treatment effect and efficiency.

[0053] At the same time, due to the relative movement between the layers of plastic mesh in the air outlet bag 42, during the exhaust gas treatment process, the shape of the air outlet bag 42 will change due to the influence of the treatment liquid fluctuation and the exhaust gas impact. In this process, the mutual overlap and division between the meshes on the layers of plastic mesh will further change, that is, the size and position of the bubbles formed by the discharged exhaust gas will change, further making the bubbles evenly distributed in the treatment liquid. Through the relative movement between the plastics, the meshes on the plastic mesh are intertwined and moved, so that the meshes remain unobstructed, ensuring the smooth formation and separation of bubbles, and reducing the possibility of clogging of the meshes on the plastic mesh.

[0054] As an embodiment of the present invention, the liquid suction pipe 43 is mounted with a telescopic hose 431, the telescopic hose 431 is mounted with an inverted U-shaped tube 432, the U-shaped tube 432 is mounted with a float 433, and the inlet of the U-shaped tube 432 is immersed in the treatment liquid;

[0055] Since the air distribution pipe 4 and the liquid suction pipe 43 are immersed in the treatment liquid layer at the bottom of the tank body 2, and the treatment liquid in the tank body 2 will dynamically fluctuate with the spraying of the nozzle 222 and the recovery of the treatment liquid by the liquid outlet pipe 21, when the amount of treatment liquid in the tank body 2 increases, the depth of the liquid suction pipe 43 in the treatment liquid will increase relatively, and the liquid pressure on the liquid suction pipe 43 will increase, so that the treatment liquid entering the air distribution pipe 4 through the liquid suction pipe 43 is relatively more. The increase in the treatment liquid entering the air distribution pipe 4 is likely to affect the effect of the high-speed airflow in the air distribution pipe 4 on the impact and dispersion of the treatment liquid, and is likely to interfere with and block the airflow ejection in the air distribution pipe 4, affecting the normal operation of the air distribution pipe 4 and the treatment and absorption effect of the exhaust gas;

[0056] At the same time, by installing a telescopic hose 431 on the suction pipe 43 and a float 433 on the U-shaped tube 432, the U-shaped tube 432 can adapt to the height change of the treatment liquid level in the tank body 2 through the action of the float 433, so that the U-shaped tube 432 always stays on the liquid surface of the treatment liquid, and the depth of the inlet of the U-shaped tube 432 immersed in the treatment liquid does not change, so that the suction pipe 43 will not be affected by the pressure of the treatment liquid when sucking the treatment liquid, and it is avoided that the suction pipe 43 will not draw in more treatment liquid when the suction pressure remains unchanged, thereby causing too much treatment liquid to enter the gas distribution pipe 4, affecting the effect of the treatment liquid being atomized by the impact of the airflow in the gas distribution pipe 4, and the effect of the exhaust gas and the atomized treatment liquid being in contact and absorbed by each other.

[0057] As an embodiment of the present invention, a mounting frame 31 is installed in the tank body 2, and the mounting frame 31 is located above the gas outlet bag 42. A fixing rod 32 is installed on the mounting frame 31, and a spiral plate 3 is rotatably installed on the fixing rod 32. The spiral plate 3 is located below the liquid surface of the treatment liquid;

[0058] At the same time, since a treatment liquid layer formed by the accumulation of treatment liquid is provided at the lower part of the tank body 2, the spiral plate 3 is installed below the liquid surface of the treatment liquid, so that the treatment liquid at the lower part of the tank body 2 is guided and guided by the spiral plate 3, thereby increasing the stirring and mixing effect of the treatment liquid at the lower part of the tank body 2 and promoting the uniform distribution of the absorption medium in the treatment liquid in the tank body 2, so that the treatment liquid in contact with the exhaust gas at various places in the tank body 2 can efficiently and fully absorb and treat the toxic and harmful gases in the exhaust gas, so that the exhaust gas discharged after treatment will not cause harm to the environment and personnel;

[0059] At the same time, since the spiral plate 3 is located below the liquid surface of the treatment liquid, the bubbles discharged from the gas distribution pipe 4 will contact the spiral plate 3 during the upward movement, and then the bubbles are guided by the spiral of the spiral plate 3, so that the bubbles formed by the exhaust gas stay in the treatment liquid for a relatively longer time, thereby increasing the contact time and contact area between the exhaust gas and the treatment liquid, and improving the exhaust gas absorption and treatment effect;

[0060] At the same time, since the spiral plate 3 is rotatably installed on the fixed rod 32, when the spiral plate 3 guides the bubbles, the spiral plate 3 will also be pushed by the bubbles, causing the spiral plate 3 to rotate or rotate slowly, thereby pushing and stirring the treatment liquid layer in the tank body 2, further promoting the uniform distribution of the treatment liquid, and sufficient contact between the treatment liquid and the exhaust gas, thereby improving the absorption and treatment effect of the exhaust gas.

[0061] As an embodiment of the present invention, a plurality of spiral plates 3 are mounted on the fixing rod 32, and the spiral directions of adjacent spiral plates 3 on the fixing rod 32 are opposite;

[0062] The number of turns of the upper spiral plate 3 on the fixing rod 32 is smaller than the number of turns of the lower spiral plate 3 , and the pitch of the upper spiral plate 3 on the fixing rod 32 is larger than the pitch of the lower spiral plate 3 . The spiral plates 3 do not contact each other, and the pipette 43 does not contact the spiral plates 3 .

[0063] A plurality of fixing rods 32 are mounted on the mounting frame 31, so that the spiral plates 3 are divided into a plurality of groups according to the fixing rods 32, and a plurality of spiral plates 3 are arranged on the fixing rods 32 to form a group, so that there are a plurality of spiral plates 3 in the tank body 2, and each group of spiral plates 3 includes a plurality of spiral plates 3. When the spiral plates 3 guide and direct the bubbles formed by the exhaust gas, and when the spiral plates 3 are slowly driven by the rising bubbles, the treatment liquid in the lower part of the tank body 2 can be stirred by the spiral plates 3 everywhere, so that the absorption medium in the treatment liquid is distributed as evenly as possible, thereby improving the exhaust gas absorption treatment effect;

[0064] At the same time, since the spiral plates 3 on the fixed rod 32 have opposite spiral directions, and the number of turns of the upper spiral plate 3 is smaller than that of the lower spiral plate 3 and the pitch of the upper spiral plate 3 is greater than that of the lower spiral plate 3, after the rising bubbles contact the spiral plates 3, the contact area and frequency of the bubbles and the lower spiral plates 3 are relatively large, so that the spiral plates 3 located at the bottom of the fixed rod 32 have a relatively large stirring and pushing effect on the treatment liquid, even if the treatment liquid is stirred and pushed upward, the uniformity of the treatment liquid is improved, and the exhaust gas is fully in contact with the treatment liquid, thereby improving the exhaust gas absorption treatment effect and treatment efficiency;

[0065] At the same time, since the spiral plates 3 do not contact each other, the spiral plates 3 are divided into multiple layers in the vertical direction, and each layer is on the same horizontal plane, such as two layers at different heights, so that there is a common and connected space between the two layers of spiral plates 3, so that the stirred and pushed treatment liquid can flow and mix freely in the space, thereby improving the uniformity of the absorption medium in the treatment liquid and ensuring the efficiency and effect of the exhaust gas absorption treatment.

[0066] As an embodiment of the present invention, the mesh sizes of adjacent plastic nets in the air outlet bag 42 are not limited to the same;

[0067] Due to the relative movement between the layers of plastic mesh in the air outlet bag 42, there will be treatment liquid between the layers of plastic mesh. Therefore, when the exhaust gas passes through the micropores on the air outlet bag 42, the bubbles formed by the exhaust gas will pass through the meshes of different sizes in turn. Combined with the misalignment between the layers of plastic mesh and the mutual overlap and cutting between the meshes, the formed bubbles will be further cut, the volume of the formed bubbles will be reduced, and the number of the formed bubbles will be increased, thereby increasing the contact area between the bubbles and the treatment liquid, and improving the absorption and treatment effect and efficiency of the exhaust gas.

[0068] The specific workflow is as follows:

[0069] During operation, the tail gas generated during the synthesis of parachlorobenzotrifluoride is sequentially introduced into the hydrogen fluoride absorption tank 1 and the hydrogen chloride absorption tank 11, so that the hydrogen fluoride gas, hydrogen chloride gas and chlorine gas in the tail gas are absorbed and processed;

[0070] At the same time, during the treatment process, the exhaust gas enters the tank body 2 of the absorption tank from the air inlet pipe 23, and then enters the connecting ring 41 and is discharged into the tank body 2 from the air distribution pipe 4 on the connecting ring 41. The exhaust gas discharged from the air distribution pipe 4 enters the treatment liquid in the tank body 2 and forms bubbles containing exhaust gas, so that the exhaust gas and the treatment liquid are fully in contact. At the same time, the exhaust gas discharged from the air distribution pipe 4 will pass through the treatment liquid layer at the lower part of the tank body 2 from bottom to top, and then the exhaust gas will continue to move upward until the exhaust gas is discharged from the tank body 2 from the air outlet pipe 24.

[0071] At the same time, during the exhaust gas treatment process, the treatment liquid is fed into the tank body 2 from the liquid inlet pipe 22. Thereafter, the treatment liquid is sprayed out from the distribution ring 221 and the nozzle 222 above the tank body 2, forming tiny treatment liquid droplets in the tank body 2 until the droplets contact and converge into the treatment liquid layer at the bottom of the tank body 2. Thereafter, the exhaust gas discharged from the gas distribution pipe 4 and moving upward will cause the exhaust gas to come into secondary contact with the droplets. At the same time, the treatment liquid layer accumulated in the lower part of the tank body 2 is discharged to the outside of the tank body 2 through the liquid outlet pipe 21, so as to circulate and replace the treatment liquid.

[0072] At the same time, since the shape of the ejection channel is a gradually expanding trumpet shape, the effect of the air distribution pipe 4 is the same as that of the Laval nozzle, so that the gas ejected from the air distribution pipe 4 into the liquid layer of the treatment liquid has a faster flow rate, which makes it easier to disperse the treatment liquid and the exhaust gas, and to generate smaller bubbles in the treatment liquid. At the same time, since the suction pipe 43 is installed on the air distribution pipe 4 and there is fast-flowing exhaust gas in the air distribution pipe 4, according to the Bernoulli principle, the treatment liquid in the tank body 2 will be sucked into the air distribution pipe 4, and the sucked treatment liquid will be impacted and dispersed into tiny droplets, so that the treatment liquid and the exhaust gas begin to make initial contact in the air distribution pipe 4, that is, the exhaust gas and the treatment liquid have a third contact.

[0073] At the same time, through multiple contacts between the exhaust gas and the treatment liquid, as well as changes in the state of the exhaust gas and the treatment liquid when they come into contact with each other, such as treatment liquid droplets and exhaust gas, and treatment liquid and exhaust gas bubbles, the exhaust gas and the treatment liquid are fully in contact and the contact time between the two is extended, thereby improving the efficiency and effect of the exhaust gas treatment. At the same time, the treatment liquid layer that drips and accumulates in the lower part of the tank body 2 will further absorb the exhaust gas, thereby maximizing the utilization rate of the absorption medium in the treatment liquid.

[0074] After the exhaust gas is ejected from the outlet of the air distribution pipe 4, the exhaust gas will fill the air outlet bag 42, causing the air outlet bag 42 to be propped up and bulged. Then, the exhaust gas that fills the air outlet bag 42 will be discharged from the micropores on the air outlet bag 42 and form tiny bubbles in the treatment liquid.

[0075] At the same time, since the surface area of the gas outlet bag 42 is relatively large and the micropores are evenly distributed on the gas outlet bag 42, the distribution range of the bubbles in the treatment liquid is increased, and the bubbles are distributed as evenly as possible, so that the exhaust gas in the bubbles can fully contact the absorption medium in the treatment liquid, thereby improving the effect and efficiency of the exhaust gas absorption treatment;

[0076] At the same time, since the gas outlet bag 42 is made of a plastic mesh and is filled and supported by the exhaust gas discharged into the gas outlet bag 42, the appearance and shape of the gas outlet bag 42 are relatively unstable and will change with the fluctuation of the treatment liquid layer and the speed and amount of exhaust gas discharged from the micropores on the gas outlet bag 42. This will cause the distribution position of the bubbles generated by the exhaust gas discharged from the micropores on the gas outlet bag 42 in the treatment liquid to change, causing the bubbles generated in the gas outlet bag 42 to be distributed and move in a disordered manner, thereby increasing the stirring effect on the treatment liquid layer and promoting the uniform distribution of the absorption medium in the treatment liquid.

[0077] At the same time, since the air outlet bag 42 is installed on the air distribution pipe 4, after the air outlet bag 42 is propped up by the exhaust gas, a relatively empty space is formed at the outlet of the air distribution pipe 4. At this time, the mist droplets sucked into the air distribution pipe 4 through the liquid suction pipe 43 and crushed by the high-speed airflow are mixed in the air distribution pipe 4 and discharged into the air outlet bag 42, where they continue to mix and fully contact with each other, thereby increasing the contact time and contact area between the mist droplets and the exhaust gas.

[0078] At the same time, as the exhaust gas is filled into the outlet bag 42 and discharged from the micropores under pressure, the treatment liquid droplets atomized by the high-speed airflow are also discharged along with the exhaust gas in the outlet bag 42. In addition, some droplets that fail to be discharged in time and are gathered and liquefied are also discharged from the micropores into the external treatment liquid layer under the relatively high pressure in the outlet bag 42.

[0079] Since the air outlet bag 42 is mounted on the enlarged mounting plate 421, and the enlarged mounting plate 421 is screwed onto the air distribution pipe 4, when the air outlet bag 42 becomes aged or damaged, the staff can easily replace the air outlet bag 42. At the same time, the air outlet bag 42 is invertedly mounted on the enlarged mounting plate 421 in the treatment liquid. After the exhaust gas is discharged from the air distribution pipe 4 into the air outlet bag 42, the air outlet bag 42 will intercept and block some particulate impurities remaining in the exhaust gas.

[0080] At the same time, after the particulate impurities remaining in the exhaust gas enter the air outlet bag 42, the particulate impurities are intercepted by the air outlet bag 42 and fall onto the expanded mounting plate 421, and the particulate impurities are collected by the expanded mounting plate 421;

[0081] Since the gas outlet bag 42 is made of multiple layers of plastic mesh stacked together, there is misalignment between the layers of plastic mesh, causing the mesh holes on the plastic mesh to overlap and split, resulting in non-uniform size and shape of the micropores on the gas outlet bag 42. As the exhaust gas is discharged from the micropores on the gas outlet bag 42, the size and frequency of bubbles formed in the micropores will vary, thereby improving the uniformity of bubble distribution in the treatment liquid and increasing the contact area between the bubbles and the treatment liquid.

[0082] At the same time, due to the relative movement between the layers of plastic mesh in the air outlet bag 42, the shape of the air outlet bag 42 changes during the exhaust gas treatment process due to the fluctuation of the treatment liquid and the impact of the exhaust gas. In this process, the overlap and division of the meshes on the layers of plastic mesh will further change, that is, the size and position of the bubbles formed by the exhaust gas will change, further making the distribution of the bubbles in the treatment liquid uniform. In addition, the relative movement between the plastics causes the meshes on the plastic mesh to intertwine and move with each other, keeping the meshes unobstructed and ensuring the smooth formation and separation of bubbles.

[0083] At the same time, by installing the telescopic hose 431 on the liquid suction pipe 43 and the floating block 433 on the U-shaped tube 432, the U-shaped tube 432 is always kept above the liquid surface of the treatment liquid by the action of the floating block 433, and the depth of the inlet of the U-shaped tube 432 immersed in the treatment liquid does not change, so that the liquid suction pipe 43 will not be affected by the pressure of the treatment liquid when sucking the treatment liquid, thereby avoiding the situation where more treatment liquid is sucked into the liquid suction pipe 43 when the suction pressure remains unchanged, causing excessive treatment liquid to enter the gas distribution pipe 4, thereby affecting the effect of the treatment liquid being atomized by the impact of the air flow in the gas distribution pipe 4, and the effect of the exhaust gas and the atomized treatment liquid being contacted and absorbed by each other.

[0084] At the same time, since a treatment liquid layer is formed by the accumulation of treatment liquid in the lower part of the tank body 2, the spiral plate 3 is installed below the liquid surface of the treatment liquid, so that the treatment liquid in the lower part of the tank body 2 is guided and guided by the spiral plate 3, thereby increasing the stirring and mixing effect of the treatment liquid in the lower part of the tank body 2;

[0085] At the same time, the bubbles discharged from the gas distribution pipe 4 will contact the spiral plate 3 during the upward movement, and then the bubbles will be guided by the spiral plate 3, so that the bubbles formed by the exhaust gas will stay in the treatment liquid for a relatively longer time, thereby increasing the contact time and contact area between the exhaust gas and the treatment liquid;

[0086] At the same time, since the spiral plate 3 is rotatably mounted on the fixed rod 32, when the spiral plate 3 guides the bubbles, the spiral plate 3 is also pushed by the bubbles, causing the spiral plate 3 to rotate or rotate slowly, pushing and stirring the treatment liquid layer in the tank body 2;

[0087] There are multiple groups of spiral plates 3 in the tank body 2, and each group of spiral plates 3 includes multiple spiral plates. When the spiral plates 3 guide and direct the bubbles formed by the exhaust gas, and the spiral plates 3 are slowly driven by the rising bubbles, the treatment liquid in the lower part of the tank body 2 can be stirred by the spiral plates 3 everywhere, so that the absorption medium in the treatment liquid is distributed as evenly as possible.

[0088] At the same time, since the spiral plates 3 do not contact each other, the spiral plates 3 are divided into multiple layers in the vertical direction, and each layer is on the same horizontal plane. For example, two layers are located at different heights, so that there is a common, connected space between the two layers of spiral plates 3, so that the stirred and pushed treatment liquid can flow and mix freely in the space, thereby improving the uniformity of the absorption medium in the treatment liquid;

[0089] When the exhaust gas passes through the micropores on the air outlet bag 42, the bubbles formed by the exhaust gas will pass through the meshes of different sizes in turn. Combined with the misalignment between the layers of plastic mesh and the overlap and cutting between the meshes, the formed bubbles will be further cut, the volume of the formed bubbles will be reduced, and the number of the formed bubbles will be increased, thereby increasing the contact area between the bubbles and the treatment liquid.

[0090] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the foregoing embodiments. The foregoing embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A tail gas absorption and purification device for the synthesis of parachlorobenzotrifluoride, comprising an absorption tank, wherein the absorption tank is provided with a liquid outlet pipe (21), an air inlet pipe (23), a liquid inlet pipe (22) and an air outlet pipe (24) from bottom to top, the absorption tank comprising a hydrogen fluoride absorption tank (1) and a hydrogen chloride absorption tank (11), the air outlet pipe (24) on the hydrogen fluoride absorption tank (1) being connected to the air inlet pipe (23) on the hydrogen chloride absorption tank (11) through a connecting pipe (12), and the lower part of the absorption tank is filled with a treatment liquid; Its characteristics are: A distribution ring (221) is installed at the upper end of the absorption tank, a nozzle (222) is installed on the distribution ring (221), the liquid inlet pipe (22) and the distribution ring (221) are communicated with each other, and the distribution ring (221) is located above the liquid surface of the treatment liquid; A communication ring (41) is installed at the lower end of the absorption tank, an air distribution pipe (4) is installed on the communication ring (41), the air inlet pipe (23) and the communication ring (41) are in communication with each other, and the air distribution pipe (4) is located below the liquid level of the treatment liquid; The air distribution pipe (4) is provided with an ejection channel in the shape of a gradually expanding trumpet. A liquid suction pipe (43) is installed on the air distribution pipe (4), and the liquid suction pipe (43) is connected to one end of the ejection channel close to the connecting ring.

2. The tail gas absorption and purification device for the synthesis of parachlorobenzotrifluoride according to claim 1, characterized in that: An air outlet bag (42) is installed on the air distribution pipe (4), and the air outlet bag (42) is located below the liquid level of the treatment liquid; The air outlet bag (42) is made of corrosion-resistant plastic mesh, and the air outlet bag (42) is composed of multiple layers of plastic mesh stacked on top of each other.

3. The tail gas absorption and purification device for the synthesis of parachlorobenzotrifluoride according to claim 2, characterized in that: An enlarged mounting plate (421) is threadedly mounted at the outlet of the air distribution pipe (4), the air outlet bag (42) is mounted on the enlarged mounting plate (421), and the air outlet bag (42) in the tank body (2) opens toward the bottom surface of the tank body (2).

4. The tail gas absorption and purification device for the synthesis of parachlorobenzotrifluoride according to claim 2, characterized in that: There is relative movement between the layers of plastic nets in the air outlet bag (42).

5. The tail gas absorption and purification device for the synthesis of parachlorobenzotrifluoride according to claim 1, characterized in that: The liquid suction pipe (43) is provided with a telescopic hose (431), an inverted U-shaped tube (432) is provided on the telescopic hose (431), a floating block (433) is provided on the U-shaped tube (432), and the inlet of the U-shaped tube (432) is immersed in the treatment liquid.

6. The tail gas absorption and purification device for the synthesis of parachlorobenzotrifluoride according to claim 1, characterized in that: A mounting frame (31) is installed in the tank body (2), and the mounting frame (31) is located above the air outlet bag (42). A fixing rod (32) is installed on the mounting frame (31), and a spiral plate (3) is rotatably installed on the fixing rod (32). The spiral plate (3) is located below the liquid surface of the treatment liquid.

7. The tail gas absorption and purification device for the synthesis of parachlorobenzotrifluoride according to claim 6, characterized in that: A plurality of spiral plates (3) are mounted on the fixing rod (32), and the spiral directions of adjacent spiral plates (3) on the fixing rod (32) are opposite; The number of turns of the spiral plate (3) located above the fixing rod (32) is smaller than the number of turns of the spiral plate (3) located below, the pitch of the spiral plate (3) located above the fixing rod (32) is larger than the pitch of the spiral plate (3) located below, the spiral plates (3) do not contact each other, and the pipette (43) does not contact the spiral plates (3).

8. The tail gas absorption and purification device for the synthesis of parachlorobenzotrifluoride according to claim 4, characterized in that: The mesh sizes of adjacent plastic nets in the air outlet bag (42) are not limited to the same.

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