A tail gas absorption purification device for p-chlorobenzotrifluoride synthesis

Abstract

The application 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, a liquid outlet pipe, an air inlet pipe, a liquid inlet pipe and a gas outlet pipe are sequentially arranged in the absorption tank from bottom to top; a distribution ring and a nozzle are arranged at the upper end in the absorption tank, the liquid inlet pipe and the distribution ring are in communication with each other; a communication ring and a gas distribution pipe are arranged at the lower end in the absorption tank, the air inlet pipe and the communication ring are in communication with each other; a spray channel is arranged in the gas distribution pipe, a liquid suction pipe is arranged on the gas distribution pipe, and the liquid suction pipe and the gas distribution pipe are arranged below the liquid surface of the treatment liquid; the tail gas and the treatment liquid are in multiple mutual contact, the state of the tail gas and the treatment liquid is changed during the contact, the contact area and the contact time are increased, the effect and the efficiency of the tail gas absorption treatment are improved, meanwhile, the treatment liquid gathered at the bottom of the tank is reused, and the utilization rate of the treatment liquid is improved as much as possible.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tail gas absorption treatment, and particularly relates to a tail gas absorption and purification device for synthesis of p-chlorobenzotrifluoride. BACKGROUND

[0002] P-chlorobenzotrifluoride is also known as p-chlorotri-fluoromethylbenzene, 4-chlorobenzotrifluoride, p-chlorobenzyl trifluoride, and p-chlorobenzotrifluoride, which is a colorless transparent liquid, insoluble in water, soluble in alcohol, ether, benzene and other organic solvents, p-chlorobenzotrifluoride is a flammable and toxic chemical, and has a stimulating effect on the skin and eyes, can burn and emit toxic gases when encountering open fire, high heat or contact with oxidizing agents. P-chlorobenzotrifluoride can be used as an intermediate for the synthesis of medicines, such as antitumor, antipsychotic, anti-Alzheimer's disease, sedative, diuretic and other drugs.

[0003] In the production process of p-chlorobenzotrifluoride, a large amount of waste gas such as hydrogen fluoride gas, hydrogen chloride gas and chlorine gas is generated, which can easily pollute the environment and cause harm to the human body, so the toxic and harmful gas needs to be absorbed and removed before the tail gas is discharged to avoid pollution of the environment and harm to personnel. SUMMARY

[0004] In order to make up for the shortcomings of the prior art, the tail gas and the treatment liquid are in contact with each other for multiple times, and the state of the two changes during the contact, the contact area and the contact time between the tail gas and the treatment liquid are increased, the effect and efficiency of the tail gas absorption treatment are improved, and at the same time, the treatment liquid gathered at the bottom of the tank is reused to improve the utilization rate of the treatment liquid as much as possible, the application provides a tail gas absorption and purification device for synthesis of p-chlorobenzotrifluoride.

[0005] The technical scheme adopted by the application to solve the technical problem is that the tail gas absorption and purification device for synthesis of p-chlorobenzotrifluoride comprises an absorption tank, the absorption tank is provided 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 in the absorption tank is filled with a treatment liquid.

[0006] The upper end in the absorption tank is provided with a distribution ring, the distribution ring is provided with a spray head, the liquid inlet pipe and the distribution ring are in communication with each other, and the distribution ring is located above the liquid level of the treatment liquid.

[0007] The lower end in the absorption tank is provided with a communication ring, the communication ring is provided with a gas distribution pipe, the air inlet pipe and the communication ring are in communication with each other, and the gas distribution pipe is located below the liquid level of the treatment liquid.

[0008] The air distribution pipe is provided with an ejection channel, the ejection channel is in the shape of a gradually expanding horn, 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 mesh, and the air outlet bag is composed of multiple layers of plastic mesh stacked on each other.

[0011] Preferably, an enlarged mounting plate is installed on the outlet of the air distribution pipe through screwing, the air outlet bag is installed on the enlarged mounting plate, and the opening of the air outlet bag in the tank body faces the bottom surface in the tank body.

[0012] Preferably, the layers of plastic mesh in the air outlet bag are relatively movable.

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

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

[0015] Preferably, multiple spiral plates are installed on the fixed rod, and the spiral directions of adjacent spiral plates on the fixed rod are opposite.

[0016] The number of turns of the spiral plate located above the fixed rod is less than the number of turns of the spiral plate located below the fixed rod, the pitch of the spiral plate located above the fixed rod is greater than the pitch of the spiral plate located below the fixed rod, the spiral plates do not contact each other, and the liquid suction pipe does not contact the spiral plates.

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

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

[0019] 1. The tail gas absorption purification device for the synthesis of p-chlorobenzotrifluoride, by setting the distribution ring, the nozzle, the communication ring, the gas distribution pipe and the liquid suction pipe, the tail gas is sprayed from the gas distribution pipe and forms bubbles in the treatment liquid, the tail gas in the bubbles is in full contact with the treatment liquid, at the same time, the droplets of the treatment liquid sprayed from the nozzle fall in the tank and fully contact with the rising tail gas, at the same time, the liquid suction pipe sucks the treatment liquid into the gas distribution pipe, and the treatment liquid is dispersed by the high-speed gas impact to form mist droplets in contact with the tail gas, so that the tail gas in the absorption tank and the treatment liquid are in contact multiple times, and the state of the two changes at each time, 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, at the same time, the bottom of the tank will accumulate the falling treatment liquid, and the gas distribution pipe releases bubbles in the treatment liquid, which continues to utilize the absorption medium in the falling treatment liquid, thereby improving the utilization rate of the treatment liquid and reducing the burden of the nozzle.

[0020] 2. The tail gas absorption purification device for the synthesis of p-chlorobenzotrifluoride, by setting the gas distribution pipe and the gas outlet bag, the tail gas discharged from the gas distribution pipe fills and lifts the gas outlet bag, the tail gas is discharged from the micropores on the gas outlet bag, a large number of bubbles are formed, and the area of the bubble release and rising area is increased, so that the bubbles are in full contact with the treatment liquid, and the number of bubbles in the local area of the treatment liquid is prevented from being too large, so that the concentration of the absorption medium in the treatment liquid is too low, and the tail gas absorption treatment effect is affected.

[0021] 3. The tail gas absorption purification device for the synthesis of p-chlorobenzotrifluoride, by setting the mounting frame, the fixed rod and the spiral plate, the rising bubbles in the treatment liquid are guided, the residence time of the bubbles in the treatment liquid is prolonged, the absorption treatment effect of the treatment liquid on the tail gas is improved, at the same time, the rising bubbles push the spiral plate, and then the spiral plate stirs and pushes the treatment liquid, so that the treatment liquid is uniformly distributed, and the absorption treatment effect and efficiency of the tail gas are further improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] The application will be further described below with reference to the drawings.

[0023] Figure 1 is a perspective view of the tail gas absorption purification device of the application;

[0024] Figure 2 is a structural schematic view of the absorption tank in the tail gas absorption purification device of the application;

[0025] Figure 3 is a structural schematic view of the liquid inlet pipe, the distribution ring and the nozzle in the absorption tank of the application;

[0026] Figure 4This is a schematic diagram of the structure of the mounting frame and spiral plate inside the absorption tank in this invention;

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

[0028] Figure 6 This is a schematic diagram of the gas distribution pipe and liquid suction pipe inside the absorption tank in this invention;

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

[0030] In the diagram: 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 bracket 31, fixing rod 32, air distribution pipe 4, connecting ring 41, air outlet bag 42, enlarged mounting plate 421, suction pipe 43, telescopic hose 431, U-shaped pipe 432, float 433. Detailed Implementation

[0031] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0032] like Figures 1 to 7 As shown, the present invention discloses a tail gas absorption and purification device for the synthesis of p-chlorotrifluorotoluene, comprising an absorption tank. The absorption tank 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, and a nozzle 222 is installed on the distribution ring 221. The liquid inlet pipe 22 is connected to the distribution ring 221, and the distribution ring 221 is located above the liquid surface 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 surface of the treatment liquid.

[0035] The air distribution pipe 4 has a spray channel, which is shaped like 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 spray channel near the connecting ring.

[0036] In operation, the tail gas generated in the synthesis of p-chlorobenzotrifluoride 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, and at the same time, using hydrogen fluoride treatment liquid in the hydrogen fluoride absorption tank 1 and using lye in the hydrogen chloride absorption tank 11, the effect of absorption and treatment of the tail gas is improved by using different treatment liquids;

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

[0038] At the same time, during the treatment process of the tail gas, the treatment liquid is sent into the tank body 2 from the liquid inlet pipe 22, then the treatment liquid is sprayed from the distribution ring 221 and the spray head 222 at the top of the tank body 2, forming small droplets of the treatment liquid in the tank body 2, until the droplets contact and converge into the treatment liquid layer at the bottom of the tank body 2. Then, in cooperation with the tail gas discharged from the gas distribution pipe 4 and moving upward, the tail gas and the droplets will be in secondary contact, further increasing the contact time and the degree of full contact between the tail gas and the treatment liquid, thereby improving the absorption efficiency and absorption effect of the tail gas treatment. At the same time, the treatment liquid layer accumulated in the lower part of the tank body 2 is discharged from the tank body 2 through the liquid outlet pipe 21, so as to circulate and replace the treatment liquid, ensure the treatment effect of the treatment liquid on the tail gas, and remove the impurities accumulated in the treatment liquid. At the same time, the discharge of the treatment liquid from the tank body 2 through the liquid outlet pipe 21 ensures the relative stability of the height of the treatment liquid accumulated in the tank body 2, avoiding too much or too little treatment liquid accumulated at the bottom of the tank body 2, which affects the normal operation of the device;

[0039] Meanwhile, since the gas distribution pipe 4 is provided with the ejection channel, and the shape of the ejection channel is gradually expanding horn shape, the effect of the gas distribution pipe 4 is the same as that of the Laval nozzle, the speed of the tail gas ejected from the gas distribution pipe 4 is relatively fast, the flow rate of the gas ejected from the gas distribution pipe 4 into the liquid layer of the treatment liquid is fast, the treatment liquid is more easily dispersed, the tail gas is more easily dispersed, the small bubbles in the treatment liquid are more easily generated, the contact area between the tail gas and the treatment liquid is increased, the absorption treatment effect of the tail gas is improved, and the treatment liquid in the tank 2 is sucked into the gas distribution pipe 4 according to the Bernoulli principle, and the sucked treatment liquid is impacted and dispersed into small droplets, so that the treatment liquid and the tail gas begin to preliminarily contact in the gas distribution pipe 4, that is, the tail gas and the treatment liquid are contacted for the third time, the contact area, the contact time and the contact degree between the tail gas and the treatment liquid are increased, and the absorption efficiency and the absorption effect of the tail gas treatment are improved.

[0040] Meanwhile, through the multiple contacts between the tail gas and the treatment liquid, and the state changes of the tail gas and the treatment liquid when they contact each other, such as the treatment liquid droplets and the tail gas, the treatment liquid and the tail gas bubbles, the tail gas and the treatment liquid are fully contacted and the contact time between them is prolonged, the efficiency and the effect of the tail gas treatment are improved, and the liquid layer of the treatment liquid accumulated in the lower part of the tank 2 further absorbs and treats the tail gas, so as to improve the utilization rate of the absorption medium in the treatment liquid as much as possible.

[0041] As an embodiment of the present application, the gas distribution pipe 4 is provided with a gas outlet bag 42, and the gas outlet bag 42 is located below the liquid surface of the treatment liquid.

[0042] The gas outlet bag 42 is made of corrosion-resistant plastic net, and the gas outlet bag 42 is composed of multiple layers of plastic nets stacked on each other.

[0043] Since the gas outlet bag 42 is composed of multiple layers of plastic nets stacked on each other, a large number of micropores exist on the gas outlet bag 42, so that after the tail gas is ejected from the outlet of the gas distribution pipe 4, the tail gas fills the gas outlet bag 42, the gas outlet bag 42 is lifted and inflated, and then the tail gas filled in the gas outlet bag 42 is discharged from the micropores on the gas outlet bag 42 and forms small bubbles in the treatment liquid.

[0044] Meanwhile, since the surface area of the gas outlet bag 42 is relatively large, and the micropores are uniformly distributed on the gas outlet bag 42, the distribution range of the bubbles in the treatment liquid is increased, the bubbles are as evenly distributed as possible, so that the tail gas in the bubbles can fully contact the absorption medium in the treatment liquid, the effect and the efficiency of the tail gas absorption treatment are improved, so as to avoid the bubbles formed by the tail gas discharged from the gas distribution pipe 4 being relatively concentrated, the absorption medium in the treatment liquid in the local area being excessively consumed, and the tail gas in the bubbles being unable to fully contact the absorption medium, thereby affecting the absorption treatment effect and the efficiency of the tail gas.

[0045] At the same time, since the air outlet bag 42 is made of plastic net and is filled and supported by the exhaust gas discharged into it, the appearance shape of the air outlet bag 42 is relatively unstable and changes with the fluctuation of the liquid layer of the treatment liquid and the speed and amount of the exhaust gas discharged from the micropores on the air outlet bag 42, so that the distribution position of the bubbles generated by the exhaust gas discharged from the micropores on the air outlet bag 42 in the treatment liquid changes, the bubbles generated by the air outlet bag 42 are distributed and moved disorderly, the stirring effect on the liquid layer of the treatment liquid is increased, the uniform distribution of the absorption medium in the treatment liquid is promoted, and the absorption and treatment effect and efficiency of the exhaust gas are ensured.

[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 supported 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 formed by the treatment liquid sucked into the air distribution pipe 4 and broken by high-speed airflow are mixed in the air distribution pipe 4, and are discharged into the air outlet bag 42 to continue to mix and fully contact with each other, so that the contact time and contact area of the mist droplets and the exhaust gas are increased, and the treatment liquid sucked and atomized is prevented from contacting with the exhaust gas only in the air distribution pipe 4 for too short time, thereby affecting the absorption and treatment effect of the exhaust gas.

[0047] At the same time, since the exhaust gas is filled into the air outlet bag 42 and is discharged from the micropores under the action of pressure, the treatment liquid mist droplets sucked and atomized by high-speed airflow are also discharged with the exhaust gas in the air outlet bag 42, and the mist droplets that fail to be discharged in time and gather and liquefy are also discharged from the micropores to the liquid layer of the treatment liquid outside under the action of relatively large pressure in the air outlet bag 42, thereby preventing the atomized liquid droplets in the air outlet bag 42 from gradually accumulating and gathering and liquefying, causing the air outlet bag 42 to be filled with the treatment liquid, and causing the air outlet bag 42 to lose its function.

[0048] As an embodiment of the present application, 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 opening of the air outlet bag 42 in the tank 2 faces the bottom surface in the tank 2.

[0049] Since the air outlet bag 42 is mounted on the enlarged mounting plate 421 and the enlarged mounting plate 421 is threadedly mounted on the air distribution pipe 4, when the air outlet bag 42 is aged or damaged, the staff can conveniently replace the air outlet bag 42, thereby conveniently maintaining the device and improving the maintenance efficiency of the device, and at the same time, the air outlet bag 42 is installed upside down 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 can intercept and block part of the particulate impurities remaining in the exhaust gas, thereby preventing the remaining particulate impurities from entering the treatment liquid and affecting the normal use of the treatment liquid.

[0050] Meanwhile, the residual particulate impurities in the tail gas will fall onto the enlarged mounting plate 421 after being intercepted by the air outlet bag 42, and then be collected by the enlarged mounting plate 421, so as to avoid the particulate impurities from falling onto the bottom surface of the air outlet bag 42 and entering the air distribution pipe 4, thereby affecting the normal use of the air distribution pipe 4.

[0051] As an embodiment of the present application, the layers of plastic nets in the air outlet bag 42 are relatively movable;

[0052] Since the air outlet bag 42 is made by stacking multiple layers of plastic nets, the layers of plastic nets in the air outlet bag 42 will be misaligned, and the mesh holes in the plastic nets will be overlapped and cut, so that the size and shape of the micro-holes in the air outlet bag 42 are not uniform. When the tail gas is discharged from the micro-holes in the air outlet bag 42, the size and frequency of the bubbles formed at the micro-holes will change, which improves the uniformity of the distribution of the bubbles in the treatment liquid and increases the contact area between the bubbles and the treatment liquid, thereby improving the absorption and treatment effect and efficiency of the tail gas.

[0053] Meanwhile, since the layers of plastic nets in the air outlet bag 42 are relatively movable, the shape of the air outlet bag 42 will change due to the influence of the fluctuation of the treatment liquid and the impact of the tail gas during the treatment of the tail gas. In this process, the mutual overlapping and cutting of the mesh holes in the layers of plastic nets will further change, that is, the size and position of the bubbles formed by the discharged tail gas will change, which further improves the uniform distribution of the bubbles in the treatment liquid and makes the mesh holes in the plastic nets interlace and move, so as to keep the mesh holes unobstructed, ensure the smooth formation and separation of the bubbles, and reduce the possibility of blockage of the mesh holes in the plastic nets.

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

[0055] As the gas distribution pipe 4 and the liquid suction pipe 43 are immersed in the treatment liquid layer at the bottom of the tank 2, and the treatment liquid in the tank 2 fluctuates dynamically with the spraying of the nozzle 222 and the recovery of the treatment liquid by the liquid outlet pipe 21, when the amount of the treatment liquid in the tank 2 increases, the depth of the liquid suction pipe 43 in the treatment liquid increases relatively, and the liquid pressure on the liquid suction pipe 43 increases, so that relatively more treatment liquid enters the gas distribution pipe 4 through the liquid suction pipe 43, and the increase of the treatment liquid entering the gas distribution pipe 4 easily affects the impact and dispersion effect of the high-speed airflow on the treatment liquid in the gas distribution pipe 4 and easily interferes with and blocks the airflow spraying in the gas distribution pipe 4, affecting the normal work of the gas distribution pipe 4 and the treatment and absorption effect on the tail gas;

[0056] At the same time, by installing the telescopic hose 431 on the liquid suction pipe 43 and the float 433 on the U-shaped pipe 432, the U-shaped pipe 432 can adapt to the height change of the treatment liquid level in the tank 2 through the action of the float 433, so that the U-shaped pipe 432 always stays on the liquid level of the treatment liquid, and the depth of the inlet of the U-shaped pipe 432 immersed in the treatment liquid does not change, so that the liquid suction pipe 43 is not affected by the pressure of the treatment liquid when sucking the treatment liquid, avoiding that more treatment liquid is sucked when the suction pressure of the liquid suction pipe 43 is constant, and further avoiding that too much treatment liquid enters the gas distribution pipe 4, affecting the effect of the treatment liquid being atomized by the airflow in the gas distribution pipe 4 and the effect of the tail gas contacting and absorbing the atomized treatment liquid.

[0057] As an embodiment of the present application, the tank 2 is provided with a mounting frame 31, the mounting frame 31 is located above the gas outlet bag 42, a fixed rod 32 is installed on the mounting frame 31, and a spiral plate 3 is rotatably installed on the fixed rod 32, the spiral plate 3 is located below the liquid level of the treatment liquid;

[0058] At the same time, since the lower part of the tank 2 is provided with a treatment liquid layer formed by the accumulation and convergence of the treatment liquid, the spiral plate 3 is installed below the liquid level of the treatment liquid, so that the treatment liquid in the lower part of the tank 2 is guided by the spiral plate 3, the stirring and mixing effect of the treatment liquid in the lower part of the tank 2 is increased, and the uniform distribution of the absorption medium in the treatment liquid in the tank 2 is promoted, so that the treatment liquid contacting the tail gas in the tank 2 can efficiently and sufficiently absorb and treat the toxic and harmful gases in the tail gas, and the discharged tail gas after treatment will not harm the environment and personnel;

[0059] At the same time, since the spiral plate 3 is located below the liquid level 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 will be spirally guided by the spiral plate 3, so that the bubbles formed by the tail gas stay in the treatment liquid for a relatively long time, the contact time and contact area of the tail gas and the treatment liquid are increased, and the absorption and treatment effect of the tail gas is improved.

[0060] At the same time, since the spiral plates 3 are rotatably installed on the fixed rods 32, when the spiral plates 3 guide the bubbles, the spiral plates 3 are pushed by the bubbles, so that the spiral plates 3 rotate or slowly rotate, thereby pushing and agitating the liquid layer of the treatment liquid in the tank body 2, further promoting the uniform distribution of the treatment liquid everywhere and the sufficient contact between the treatment liquid and the tail gas, and improving the absorption treatment effect of the tail gas.

[0061] As an embodiment of the present application, a plurality of spiral plates 3 are installed on the fixed rods 32, and the spiral directions of the adjacent spiral plates 3 on the fixed rods 32 are opposite.

[0062] The number of turns of the spiral plates 3 located above on the fixed rods 32 is less than that of the spiral plates 3 located below, and the pitch of the spiral plates 3 located above on the fixed rods 32 is greater than that of the spiral plates 3 located below, the spiral plates 3 do not contact each other, and the liquid suction pipe 43 does not contact the spiral plates 3.

[0063] A plurality of fixed rods 32 are installed on the mounting frame 31, so that the spiral plates 3 are divided into a plurality of groups according to the fixed rods 32, and a group of spiral plates 3 is arranged on each fixed rod 32, so that there are a plurality of groups of spiral plates 3 in the tank body 2, each group of spiral plates 3 includes a plurality of spiral plates 3, when the spiral plates 3 guide the bubbles formed by the tail gas and are slowly driven by the rising bubbles, the treatment liquid at the lower part of the tank body 2 can be agitated by the spiral plates 3, the absorption medium in the treatment liquid is as uniformly distributed as possible, and the tail gas absorption treatment effect is improved.

[0064] At the same time, since the spiral directions of the spiral plates 3 on the fixed rods 32 are opposite, the number of turns of the spiral plates 3 located above is less than that of the spiral plates 3 located below, and the pitch of the spiral plates 3 located above is greater than that of the spiral plates 3 located below, so that when the rising bubbles contact the spiral plates 3, the contact area and frequency of the bubbles with the spiral plates 3 located below are relatively large, thereby the agitating and pushing effect of the spiral plates 3 located below on the fixed rods 32 on the treatment liquid is relatively large, even if the treatment liquid is agitated and pushed upward, the uniformity of the treatment liquid is improved, the tail gas is fully contacted with the treatment liquid, and the tail gas absorption treatment effect and efficiency are improved.

[0065] At the same time, since the spiral plates 3 do not contact each other, the spiral plates 3 will be divided into a plurality of layers in the vertical direction, each layer will be on the same horizontal plane, such as two layers located at different heights, thereby there will be a common and connected space between the two layers of spiral plates 3, and the agitated and pushed treatment liquid can flow and mix in the space, the uniformity of the absorption medium in the treatment liquid is improved, and the efficiency and effect of the tail gas absorption treatment are ensured.

[0066] As an embodiment of the present application, the size of the mesh holes on the adjacent plastic nets in the air outlet bag 42 is not limited to be the same;

[0067] Due to the relative movement between the plastic nets in the air outlet bag 42, the treatment liquid is also present between the plastic nets, so that when the tail gas passes through the micro-holes on the air outlet bag 42, the bubbles formed by the tail gas will pass through the mesh holes of different sizes in turn, and the bubbles will be further cut, the volume of the bubbles will be reduced, and the number of the bubbles will be increased, so that the contact area between the bubbles and the treatment liquid is increased, and the absorption and treatment effect and efficiency of the tail gas are improved.

[0068] The specific working process is as follows:

[0069] During operation, the tail gas generated in the synthesis process of p-chlorobenzotrifluoride is sequentially introduced into the hydrogen fluoride absorption tank 1 and the hydrogen chloride absorption tank 11, so that the hydrogen fluoride gas, the hydrogen chloride gas and the chlorine gas present in the tail gas are absorbed and treated;

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

[0071] At the same time, during the treatment process of the tail gas, the treatment liquid is sent into the tank body 2 from the liquid inlet pipe 22, then the treatment liquid is sprayed from the distribution ring 221 and the spray head 222 at the top of the tank body 2, and small liquid droplets of the treatment liquid are formed in the tank body 2 until the liquid droplets contact and converge into the treatment liquid layer at the bottom of the tank body 2. Then, in cooperation with the upward moving tail gas discharged from the gas distribution pipe 4, the tail gas and the liquid droplets will be in secondary contact. At the same time, the treatment liquid layer accumulated at the lower part of the tank body 2 is discharged from the tank body 2 through the liquid outlet pipe 21, so as to circulate and replace the treatment liquid.

[0072] Meanwhile, since the shape of the ejection channel is gradually expanding horn shape, the effect of the air distribution pipe 4 is the same as that of the Laval nozzle, the gas flow rate in the air distribution pipe 4 ejected into the liquid layer of the treatment liquid is faster, and it is easier to disperse the treatment liquid and the exhaust gas, and to generate small bubbles in the treatment liquid. At the same time, since the liquid suction pipe 43 is installed on the air distribution pipe 4, and there is a fast flowing exhaust gas in the air distribution pipe 4, according to Bernoulli's principle, the treatment liquid in the tank 2 will be sucked into the air distribution pipe 4, and the sucked treatment liquid will be impacted and dispersed into small droplets, so that the treatment liquid and the exhaust gas begin to contact in the air distribution pipe 4, that is, the exhaust gas and the treatment liquid contact for the third time;

[0073] At the same time, through multiple contacts between the exhaust gas and the treatment liquid, and the state changes 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 contacted and the contact time between them is prolonged, the efficiency and effect of exhaust gas treatment are improved, and at the same time, the treatment liquid liquid layer accumulated in the lower part of the tank 2 will further absorb the exhaust gas, and the utilization rate of the absorption medium in the treatment liquid will be as high as possible;

[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, so that the air outlet bag 42 is lifted and inflated, and then the exhaust gas filled in the air outlet bag 42 will be discharged from the micro-holes on the air outlet bag 42 and form small bubbles in the treatment liquid;

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

[0076] At the same time, since the air outlet bag 42 is made of plastic net, and the air outlet bag 42 will be filled and lifted by the exhaust gas discharged into it, the appearance shape of the air outlet bag 42 is relatively unstable, and will change with the fluctuation of the treatment liquid layer and the speed and amount of exhaust gas discharged from the micro-holes on the air outlet bag 42, so that the distribution position of the bubbles generated by the exhaust gas discharged from the micro-holes on the air outlet bag 42 changes in the treatment liquid, and the bubbles generated on the air outlet bag 42 are distributed and moved disorderly, which increases the stirring effect on the treatment liquid layer and promotes 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 lifted 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 formed by the liquid suction pipe 43 sucked into the air distribution pipe 4 and impacted by high-speed airflow are mixed in the air distribution pipe 4, and continue to mix and fully contact after being discharged into the air outlet bag 42, which increases the contact time and contact area of the mist droplets and the exhaust gas;

[0078] At the same time, due to the exhaust gas into the air bag 42, and the exhaust gas will be discharged from the micro hole under the action of pressure, the high-speed airflow suction, impact atomized treatment liquid droplets will also be discharged with the exhaust gas in the air bag 42, and part of the droplets that failed to discharge in time and gathered liquid will also be discharged from the micro hole to the outside of the treatment liquid liquid layer under the action of relatively large pressure in the air bag 42;

[0079] Since the air bag 42 is installed on the enlarged mounting plate 421, and the enlarged mounting plate 421 is installed on the air distribution pipe 4 by screwing, when the air bag 42 is aging or damaged, the staff can conveniently replace the air bag 42, and at the same time, the air bag 42 is installed upside down 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 bag 42, the air bag 42 will intercept and block part of the particulate impurities remaining in the exhaust gas;

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

[0081] Since the air bag 42 is made by overlapping multiple layers of plastic nets, there will be a misalignment between the layers of plastic nets, which will cause the mesh holes on the plastic nets to overlap and cut each other, so that the size and shape of the micro holes on the air bag 42 are not uniform, and when the exhaust gas is discharged from the micro holes on the air bag 42, the size and frequency of the bubbles formed at the micro holes will change, which improves the uniformity of the distribution of bubbles in the treatment liquid and increases the contact area between the bubbles and the treatment liquid;

[0082] At the same time, since the layers of plastic nets in the air bag 42 can move relative to each other, during the treatment of exhaust gas, affected by the fluctuation of the treatment liquid and the impact of the exhaust gas, the shape of the air bag 42 will change, and in this process, the mutual overlapping and cutting of the mesh holes on the layers of plastic nets will further change, that is, the size and position of the bubbles formed by the exhaust gas will change, which further makes the bubbles in the treatment liquid more evenly distributed, and through the relative movement between the plastic nets, the mesh holes on the plastic nets will be interlaced and moved, so that the mesh holes remain unobstructed, ensuring that the bubbles can be formed and separated smoothly;

[0083] Meanwhile, by installing the telescopic hose 431 on the suction tube 43 and the float 433 on the U-shaped tube 432, the U-shaped tube 432 is always kept on the liquid surface of the treatment liquid by the action of the float 433, and the depth of the inlet of the U-shaped tube 432 immersed in the treatment liquid does not change, so that the suction of the suction tube 43 is not affected by the pressure of the treatment liquid, avoiding the suction of more treatment liquid when the suction pressure of the suction tube 43 is constant, so that too much treatment liquid enters the gas distribution pipe 4, affecting the effect of the treatment liquid being atomized by the airflow in the gas distribution pipe 4 and the effect of the tail gas and the atomized treatment liquid contacting and absorbing each other;

[0084] Meanwhile, the lower part of the tank body 2 is provided with a treatment liquid layer formed by the accumulation of the treatment liquid, and 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 by the spiral plate 3, increasing the stirring and mixing effect of the treatment liquid in the lower part of the tank body 2;

[0085] Meanwhile, the bubbles discharged from the gas distribution pipe 4 will contact the spiral plate 3 during upward movement, and then the bubbles will be guided by the spiral plate 3, so that the bubbles formed by the tail gas stay in the treatment liquid for a relatively long time, increasing the contact time and contact area of the tail gas and the treatment liquid;

[0086] Meanwhile, the spiral plate 3 is rotatably installed on the fixed rod 32, and 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 slowly rotate, pushing and stirring the treatment liquid layer in the tank body 2;

[0087] There are multiple sets of spiral plates 3 in the tank body 2, and each set of spiral plates 3 includes multiple spiral plates 3. When the spiral plates 3 guide the bubbles formed by the tail 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, and the distribution of the absorption medium in the treatment liquid is as uniform as possible;

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

[0089] When the exhaust gas passes through the micropores on the gas outlet bag 42, the bubbles formed by the exhaust gas will pass through the mesh holes of different sizes in turn. In combination with the misalignment between the plastic mesh layers and the mutual superposition and segmentation between the mesh holes, the bubbles formed will be further cut, the volume of the bubbles formed will be reduced, the number of the bubbles formed will be increased, and thus the contact area between the bubbles and the treatment liquid will be increased.

[0090] The basic principles, main features and advantages of the present application are shown and described above. Those skilled in the art should understand that the present application is not limited by the above examples, and the above examples and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application. The scope of protection of the present application is defined by the appended claims and their equivalents.

Claims

1. A tail gas absorption and purification device for the synthesis of p-chlorotrifluorotoluene, 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), wherein 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) via a connecting pipe (12), and the lower part of the absorption tank is filled with a treatment liquid; Its features 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) is connected to the distribution ring (221). The distribution ring (221) is located above the liquid surface of the treatment liquid. A connecting ring (41) is installed at the lower end of the absorption tank. A gas distribution pipe (4) is installed on the connecting ring (41). The air inlet pipe (23) is connected to the connecting ring (41). The gas distribution pipe (4) is located below the liquid surface of the treatment liquid. The air distribution pipe (4) has an ejection channel, which is shaped like a gradually expanding trumpet. A suction pipe (43) is installed on the air distribution pipe (4), and the suction pipe (43) is connected to one end of the ejection channel near the connecting ring (41). 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; The vent bag (42) is made of corrosion-resistant plastic mesh, and the vent bag (42) is composed of multiple layers of plastic mesh stacked together. An enlarged mounting plate (421) is threadedly installed at the outlet of the air distribution pipe (4), and the air outlet bag (42) is installed on the enlarged mounting plate (421). The opening of the air outlet bag (42) inside the tank (2) faces the bottom surface inside the tank (2). The tank (2) is equipped with a mounting frame (31), which 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. Multiple spiral plates (3) are installed on the fixed rod (32), and the spiral directions of adjacent spiral plates (3) on the fixed rod (32) are opposite. The number of turns of the upper spiral plate (3) on the fixed rod (32) is less than the number of turns of the lower spiral plate (3), the pitch of the upper spiral plate (3) on the fixed rod (32) is greater than the pitch of the lower spiral plate (3), the spiral plates (3) do not contact each other, and the suction tube (43) does not contact the spiral plates (3).

2. The tail gas absorption and purification device for the synthesis of p-chlorotrifluorotoluene according to claim 1, characterized in that: There is relative movement between the layers of plastic mesh in the vent bag (42).

3. The tail gas absorption and purification device for the synthesis of p-chlorotrifluorotoluene according to claim 1, characterized in that: A telescopic hose (431) is installed on the suction tube (43), an inverted U-shaped tube (432) is installed on the telescopic hose (431), a float (433) is installed on the U-shaped tube (432), and the inlet of the U-shaped tube (432) is immersed in the treatment liquid.

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