A device and method for treating a methylamine production tail gas

Abstract

The application provides a device for treating methylamine production tail gas, which comprises an absorption tube, an air inlet pipe, a recovery liquid storage tank, a reflux pipe and a liquid inlet pipe, the air inlet pipe is connected with a tail gas discharge device of a methylamine production system, the liquid inlet pipe is connected with an absorption liquid supply device, a first end of the absorption tube is connected with the air inlet pipe and a second end of the absorption tube is connected with the liquid inlet pipe, the first end of the absorption tube is provided with a plurality of absorption tube peaks and absorption tube valleys in a gradually rising manner from the first end to the second end, and a tail gas outlet is arranged above the second end of the absorption tube at a position higher than the liquid inlet pipe; the first end of the absorption tube is connected with the recovery liquid storage tank through a recovery pipe provided with a control valve, and the recovery pipe is connected with the liquid inlet pipe through a reflux pipe provided with a pressure pump. The application prolongs the contact time of the tail gas and the absorption liquid, the absorption liquid absorbs the tail gas during flowing in the absorption tube, greatly improves the absorption capacity and effect of the absorption liquid, and the device is simple and easy to popularize.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of methylamine production, and more particularly to a device and method for treating tail gas of methylamine production. BACKGROUND

[0002] In the industrial synthesis of methylamine, the vent tail gas discharged from the synthesis process and the distillation separation process contains ammonia and a small amount of methylamine. If directly discharged into the atmosphere, it will cause pollution. Therefore, ammonia and methylamine in the tail gas are usually recovered by low-temperature methanol absorption. For the recovery of tail gas, the prior art usually uses a tail gas absorption tower to send the absorption liquid to the upper part of the absorption tower for spraying. The absorption liquid is in countercurrent contact with the tail gas to be treated in the absorption tower, absorbs the gas in the tail gas that can be dissolved in the absorption liquid, and the unabsorbed gas is discharged from the top of the absorption tower. The absorption liquid after absorbing the tail gas is discharged from the bottom of the absorption tower.

[0003] Patent CN214552457U discloses a tail gas absorption device, which comprises a tail gas treatment tower, a top cover installed on the top of the tail gas treatment tower, an exhaust pipe installed on the top of the top cover, a shunt pipe installed in the tail gas treatment tower, a sealing cover installed on one side of the tail gas treatment tower in a hinged manner, a waste gas inlet installed on one side of the sealing cover, a tail gas adsorption treatment box installed on the inner side of the sealing cover through a fixing frame, and a waste liquid collection box installed at the bottom of the tail gas treatment tower. A waste liquid filter layer is installed in the waste liquid collection box. The waste liquid collection box can recycle the spray liquid waste generated during the tail gas treatment process, purify the waste liquid, and reuse the spray liquid, thereby saving resources. The patent uses a spraying method to absorb the tail gas. In the process of the tail gas rising and the absorption liquid descending, the absorption liquid does not fully contact the tail gas, resulting in that part of the tail gas is not absorbed by the descending absorption liquid in time and is directly discharged from the exhaust pipe at the top of the absorption tower, causing the problem of insufficient absorption and low absorption rate of the tail gas absorption and recovery.

[0004] In view of the low absorption rate problem of the above-mentioned spraying method of tail gas absorption, some patents disclose a method of directly absorbing the tail gas into the absorption liquid to improve the absorption efficiency.

[0005] The patent CN214233488U discloses a tail gas absorption tower, the inside of the tower body is connected with a partition, the bottom side of the tower body is connected with a first box body, the inside of the first box body is connected with acid liquid, the inside of the tower body is connected with a gas inlet pipe, the inside of the tower body is connected with a second liquid inlet pipe, the inside of the second liquid inlet pipe is connected with a second intelligent electromagnetic flowmeter, through the first box body, the acid liquid, the second box body and the lye, the tail gas enters the acid liquid along the gas inlet pipe, so that the dimethylamine in the tail gas reacts with the acid to convert into dimethylamine salt, and the tail gas after reacting with the acid liquid chemically reacts with the lye, so that the formic acid in the tail gas reacts with the lye to convert into formic acid salt, through the soaking mode of the acid liquid and the lye, on one hand, the tail gas is fully contacted with the liquid to improve the reaction efficiency, and on the other hand, the liquid cost is saved, and the problem of increasing the processing cost due to the low adsorption efficiency is solved. However, when the tail gas is introduced into the acid liquid or the lye, the gas stays in the liquid for a short time, and in the case that the liquid is in a static state, the dissolution degree of the gas in the liquid is limited. In addition, after the tail gas is discharged from the acid liquid or the lye, it is difficult to discharge the liquid filled in the space above the tail gas to the downstream process, and after the absorption is completed, the tail gas remaining in the space of the device cannot be completely discharged, which still causes pollution to the environment. Moreover, the liquid for absorbing the tail gas does not flow, and after a period of time of absorbing the tail gas, the absorption capacity of the liquid is reduced, so that the liquid needs to be replaced after the device is stopped, which is inconvenient to operate and has poor continuity.

[0006] In view of the above-mentioned deficiencies of the tail gas absorption device and method in the prior art, there is still an urgent need to provide a device and method capable of fully utilizing absorption liquid to absorb tail gas. SUMMARY

[0007] In order to solve the above technical problems, the present application provides a device and method for treating tail gas in methylamine production.

[0008] The basic idea of the technical scheme of the present application is as follows:

[0009] A device for treating tail gas in methylamine production, comprising an absorption pipe, a gas inlet pipe, a recovery liquid storage tank, a reflux pipe and a liquid inlet pipe, the gas inlet pipe is connected to a tail gas discharge device of a methylamine production system, the liquid inlet pipe is connected to a supply device of absorption liquid, the first end of the absorption pipe is connected to the gas inlet pipe, and the second end of the absorption pipe is connected to the liquid inlet pipe, the first end of the absorption pipe is provided with a plurality of absorption pipe peaks and absorption pipe valleys in a gradually rising manner from the first end to the second end, and the second end of the absorption pipe is provided with a tail gas outlet above the position connected to the liquid inlet pipe;

[0010] The first end of the absorption pipe is connected to the recovery liquid storage tank through a recovery pipe provided with a control valve, and the recovery pipe is connected to the liquid inlet pipe through a reflux pipe provided with a pressure pump.

[0011] As a case, the connecting part of the air inlet pipe and the absorption pipe is provided with a movable plate, the upper end of the movable plate is rotationally connected with the highest part of the outlet of the air inlet pipe and can be unidirectionally rotated towards the inside of the absorption pipe, the lower end of the movable plate vertically extends downwards and can shield the outlet of the air inlet pipe, and a gap is formed between the lower edge of the movable plate and the outlet of the air inlet pipe and serves as an air inlet.

[0012] As a case, a plurality of disturbance units for disturbing and stirring the absorption liquid in the absorption pipe are arranged on the inner wall of the absorption pipe, and the disturbance units are driven by liquid or gas entering or exiting the absorption pipe.

[0013] The disturbance unit comprises a fixing member, a connecting member, a connecting rod and a disturbance ball, the fixing member is fixed on the inner wall of the absorption pipe, the connecting member is rotationally connected with the fixing member, one end of the connecting rod is connected with the connecting member and the other end is connected with the disturbance ball.

[0014] As a case, the processing device further comprises a buffer tank, the inlet of the buffer tank is connected with the liquid inlet pipe through a liquid inlet branch pipe, and the outlet of the buffer tank is connected with the second end of the absorption pipe through a liquid outlet pipe.

[0015] As a case, the outlet of the buffer tank is provided with a movable valve, the upper end of the movable valve is connected with the side wall of the buffer tank through a rotating shaft, the lower end of the movable valve is provided with a first magnetic block, and the bottom plate of the buffer tank is correspondingly provided with a second magnetic block near the lower end of the movable valve.

[0016] The magnetic adsorption between the first magnetic block and the second magnetic block is controlled by adjusting the amount of absorption liquid entering the buffer tank to control the opening and closing state of the movable valve.

[0017] As a case, the rising section of each absorption pipe peak is longer than the corresponding descending section, and the rising sections are sequentially arranged in the order of the first absorption pipe peak, the first absorption pipe valley, the second absorption pipe peak, the second absorption pipe valley, the third absorption pipe peak and the third absorption pipe valley from the first end of the absorption pipe to the second end of the absorption pipe, and the tail gas inlet pipe is arranged at the bottom of the rising section of the first absorption pipe peak.

[0018] As a case, the peak top of the absorption pipe peak is a horizontal structure, and the peak bottom of the absorption pipe peak, the valley top and the valley bottom of the absorption pipe valley are all arc structures.

[0019] The present application provides a kind of methanamine production tail gas processing method, using the processing device as described in any one of the above is handled.

[0020] As a case, the methanamine production tail gas processing method comprises the following steps:

[0021] Step 1, check the connection state of the methanamine production tail gas processing device to ensure that there is no gas leakage, liquid leakage phenomenon;

[0022] Step 2, close the control valve;

[0023] Step 3, the liquid inlet pipe is connected to the absorption liquid, and a part of the absorption liquid enters the absorption pipe through the liquid inlet pipe, and preferably another part of the absorption liquid enters the buffer tank arranged between the absorption pipe and the liquid inlet pipe through the liquid inlet branch pipe;

[0024] Step 4, when the absorption liquid reaches the recovery pipe, the pressure pump is started to send the absorption liquid flowing into the recovery pipe into the return pipe and into the liquid inlet pipe, and then into the absorption pipe, forming a circulation;

[0025] Step 5, the exhaust gas to be treated is sent into the absorption pipe through the gas inlet pipe, and the absorption of the exhaust gas is started;

[0026] Step 6, while the exhaust gas is sent into the absorption pipe, the return control valve is opened to recover the absorption liquid after absorbing the exhaust gas.

[0027] Compared with the prior art, the present application has the following advantages:

[0028] 1. The absorption device of the present application increases the contact time of the exhaust gas and the absorption liquid by the serpentine upward arrangement of the absorption pipe, and the absorption liquid absorbs the exhaust gas during the flow in the absorption pipe, greatly improving the absorption capacity and effect of the absorption liquid.

[0029] 2. In a further preferred embodiment, a disturbance unit is arranged on the inner wall of the absorption pipe, and the disturbance ball of the disturbance unit is used to disturb the liquid in the absorption pipe, thereby increasing the reaction and dissolution capacity of the exhaust gas in the absorption liquid and improving the absorption rate.

[0030] 3. In a further preferred embodiment, the buffer tank is arranged to further increase the stirring effect of the disturbance unit, and the disturbance and stirring degree is intensified under the cooperation of the buffer tank, thereby improving the exhaust gas absorption effect, and the process is mainly driven by the gravitational force of the liquid itself, by means of the conversion between potential energy and kinetic energy, without consuming additional power, thereby reducing the power cost in the exhaust gas treatment process.

[0031] Other features and advantages of the present application will be set forth in the following description, and in part will become apparent to those skilled in the art from the description, or can be learned by practice of the present application. The objects and other advantages of the present application can be achieved and obtained by the structures specifically pointed out in the specification, claims and drawings. BRIEF DESCRIPTION OF DRAWINGS

[0032] The accompanying drawings are used to provide a further understanding of the technical solutions of the present application, and constitute a part of the specification, and together with the embodiments of the present application are used to explain the technical solutions of the present application, and do not constitute a limitation on the technical solutions of the present application.

[0033] Figure 1 is a structural schematic view of the exhaust gas treatment device for the production of methylamine described in the present application.

[0034] Figure 2 is a structural schematic diagram of the disturbance unit.

[0035] Figure 3 is a partial structural schematic diagram of the gas inlet pipe and the absorption pipe.

[0036] Figure 4 is a schematic diagram of the buffer tank in the liquid storage state.

[0037] Figure 5 is a schematic diagram of the buffer tank in the liquid discharge state.

[0038] Figure 6 is a schematic diagram of the movable valve in the buffer tank when closed.

[0039] Figure 7 is a schematic diagram of the movable valve in the buffer tank when opened.

[0040] Explanation of reference signs:

[0041] 11 absorption pipe; 12 disturbance unit; 13 gas inlet pipe; 14 return pipe; 15 recovery liquid storage tank; 16 pressure pump; 17 liquid inlet pipe; 18 buffer tank; 111 absorption pipe peak top; 112 absorption pipe peak bottom; 113 absorption pipe valley top; 114 absorption pipe valley bottom; 115 tail gas outlet; 116 absorption pipe inner wall; 121 fixing part; 122 connecting part; 123 connecting rod; 124 disturbance ball; 131 movable plate; 132 gas inlet; 151 recovery pipe; 152 control valve; 171 liquid inlet branch pipe; 181 movable valve; 182 liquid discharge pipe; 183 rotating shaft; 184 first magnetic block; 185 second magnetic block; 186 buffer tank bottom plate. DETAILED DESCRIPTION

[0042] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be described below in conjunction with the drawings of the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the described embodiments of the present application, all other embodiments obtained by those of ordinary skill in the art without any creative effort belong to the scope of protection of the present application.

[0043] Embodiment 1

[0044] As Figures 1-7As shown, the tail gas treatment device of methylamine production includes an absorption tube 11, an inlet gas tube 13, a recovery liquid storage tank 15, a reflux tube 14 and an inlet liquid tube 17. The inlet gas tube 13 is connected to the tail gas discharge device of the methylamine production system, and the inlet liquid tube 17 is connected to the supply device of the absorption liquid. The first end of the absorption tube 11 is connected to the inlet gas tube 13, and the second end is connected to the inlet liquid tube 17. The first end of the absorption tube 11 is gradually curved and rises from the first end connected to the inlet gas tube 13 to the second end connected to the inlet liquid tube 17. The second end of the absorption tube 11 is provided with a tail gas outlet 115 at a position higher than the upper part connected to the inlet liquid tube 17.

[0045] See Figure 1 The first end of the absorption tube 11 is lower than the second end of the absorption tube 11, and a plurality of absorption tube peaks and absorption tube valleys are arranged between the two ends.

[0046] Preferably, the rising section of each absorption tube peak is longer than the corresponding descending section, and the first end of the absorption tube 11 is arranged in the direction from the first end to the second end of the absorption tube 11 in the manner of a first absorption tube peak, a first absorption tube valley, a second absorption tube peak, a second absorption tube valley, a third absorption tube peak and a third absorption tube valley. The first absorption tube peak is lower than the second absorption tube peak, the second absorption tube peak is lower than the third absorption tube peak, the first absorption tube valley is lower than the second absorption tube valley, and the second absorption tube valley is lower than the third absorption tube valley. The tail gas inlet tube 13 is arranged at the bottom of the rising section of the lowest absorption tube peak (i.e. the first absorption tube peak).

[0047] The tail gas entering the inside of the absorption tube 11 is gradually transferred to the highest side of the absorption tube 11 along the absorption tube 11 which has an overall upward trend. In this process, the tail gas that can be absorbed is fully absorbed by the absorption liquid in the absorption tube 11, and the other tail gas that cannot be absorbed is discharged through the tail gas outlet 115 at the highest part of the absorption tube 11.

[0048] The first end of the absorption tube 11 is also connected to the recovery liquid storage tank 15 through a recovery tube 151 provided with a control valve 152, and the recovery tube 151 is connected to the inlet liquid tube 17 through a reflux tube 14 provided with a pressure pump 16.

[0049] Part of the absorption liquid discharged from the lower end of the absorption tube 11 enters the recovery liquid storage tank 15, and part of it is sent into the inlet liquid tube 17 through the reflux tube 14 and the pressure pump 16. The absorption liquid is again introduced into the absorption tube 11 together with the fresh absorption liquid supplied by the inlet liquid tube 17, achieving the effect of fully utilizing the absorption liquid to absorb the tail gas.

[0050] The purpose of the reflux tube 14 is to send part of the absorption liquid that has absorbed the tail gas back to the upper end of the absorption tube 11 for repeated absorption and utilization.

[0051] As Figure 3As shown, in one embodiment, a movable plate 131 is provided at the connection between the intake pipe 13 and the absorber pipe 11 (i.e., the outlet of the intake pipe 13). The upper end of the movable plate 131 is rotatably connected to the highest point of the connection between the intake pipe 13 and the absorber pipe 11 so as to rotate unidirectionally toward the inside of the absorber pipe 11 (the movable plate 131 cannot rotate toward the inside of the intake pipe 13). The lower end of the movable plate 131 extends vertically downward and can cover the inner diameter of the intake pipe 13. A gap is left between the lower edge of the movable plate 131 and the inner diameter of the intake pipe 13, which serves as an air inlet 132.

[0052] The movable plate 131 here is unidirectional, meaning it can only rotate towards the inside of the absorption tube 11 and not towards the inside of the intake tube. The gap formed between the lower edge of the movable plate 131 and the lower edge of the outlet of the intake tube 13 facilitates the entry of gas from the intake tube into the absorption tube.

[0053] Here, the inclined opening at the connection interface formed by the inclined angle of the absorber pipe 11 and the intake pipe 13 is utilized, and a movable plate 131 is provided. The device is simple and does not require an additional valve control system. The design intent and beneficial effects of the movable plate 131 are as follows:

[0054] like Figure 1 As shown, the intake pipe 13 is horizontally positioned, and the absorption pipe 11 is inclined. The connection between the two is an opening with an angled surface (i.e., the outlet of the intake pipe 13). When the movable plate 131 is in a free state, it remains vertical and cannot rotate in the direction of the intake pipe 13. The movable plate 131 will not completely close the aforementioned opening. The size of the movable plate 131 is larger than the inner diameter of the intake pipe 13, mainly to prevent liquid in the absorption pipe 11 from flowing back into the intake pipe 13. On the one hand, the purpose of setting a partially sealed enclosure is to facilitate the entry of gas in the intake pipe 13 into the absorption pipe 11 through the gap formed by the movable plate 131 and the aforementioned opening with an inclined surface. When gas enters the absorption pipe 11 from the intake pipe 13 and the intake pressure is greater than the liquid pressure in the absorption pipe 11, the gas pushes the movable plate 131 to rotate inward into the absorption pipe 11, making the opening between the intake pipe 13 and the absorption pipe 11 larger, which is more conducive to the entry of gas in the intake pipe 13 into the absorption pipe 11. When the intake pressure is equal to or less than the liquid pressure in the absorption pipe 11, the movable plate 131 is in its initial vertical state. At this time, the exhaust gas in the intake pipe 13 enters the absorption pipe 11 from the intake port 132 between the lower edge of the movable plate 131 and the lower edge of the inner diameter of the intake pipe 13.

[0055] On the other hand, with the above-described configuration, even if the amount of exhaust gas is small and the pressure is low during the exhaust gas absorption process, it can still enter the absorption pipe 11 through the air inlet 132 for exhaust gas absorption treatment, and the liquid in the absorption pipe 11 will not flow back into the air inlet pipe 13. This simply prevents the liquid in the absorption pipe 11 from entering the air inlet pipe 13.

[0056] The gas that enters the absorption tube 11 then rises along the inclined absorption tube 11, and is continuously dissolved and absorbed by the absorption liquid in the absorption tube 11 during the rising process.

[0057] like Figure 1 As shown, the inlet pipe 17 is located at the top of the rising section of the highest absorption pipe peak. The absorbent liquid entering the absorption pipe 11 flows gradually from the highest point of the absorption pipe 11 to the lowest point of the absorption pipe 11 under its own gravity. During this process, the exhaust gas is absorbed and enters the recovery liquid storage tank 15 through the recovery pipe 151.

[0058] As an optimization, the peak 111 of the absorption tube is designed as a horizontal structure to prevent rising gas in the pipe from accumulating at the top of the absorption tube peak and being difficult to transfer. The bottom 112 of the absorption tube peak is designed as an arc shape, which facilitates the smooth passage of liquid in the absorption tube 11 from top to bottom through the absorption tube peak, and also facilitates the smooth passage of gas in the absorption tube 11 through the absorption tube peak.

[0059] The top 113 and bottom 114 of the absorption tube valley are both designed as arc-shaped structures, which facilitates the smooth passage of gas and liquid in the absorption tube 11 through the absorption tube valley and prevents gas or liquid from lingering and accumulating in the absorption tube valley.

[0060] As an optimization solution, such as Figures 1-2 As shown, multiple disturbance units 12 are provided on the inner wall 116 of the absorption tube to disturb and stir the absorption liquid in the absorption tube 11, which is beneficial to promote the reaction and dissolution process of the exhaust gas in the absorption liquid.

[0061] The disturbance unit 12 includes a fixing member 121, a connecting member 122, a connecting rod 123, and a disturbance ball 124. The fixing member 121 is fixed to the inner wall 116 of the absorption tube, and the connecting member 122 is disposed on the fixing member 121. The connecting member 122 is connected to the disturbance ball 124 through the connecting rod 123. The connecting rod 123 is fixedly connected to the connecting member 122, while the connecting member 122 is rotatably connected to the fixing member 121. The connecting rod 123 can rotate relative to the fixing member 121 within a certain angle range through the connecting member 122, thereby driving the disturbance ball 124 to rotate.

[0062] As an alternative, to enhance the perturbation effect of the perturbation ball 124, the connecting rod 123 and the connecting piece 122 can also be movably connected.

[0063] When the disturbing ball 124 receives different thrusts in different directions, it will move in a spherical surface within a certain range, with the connecting rod 123 and the connecting piece 122 as the center of the ball and the length of the connecting rod 123 as the radius of the ball. The range of the movement of the disturbing ball 124 depends on the way of the movable connection between the connecting rod 123 and the connecting piece 122 and the length of the connecting rod 123.

[0064] During the relative movement of the liquid from top to bottom and the gas from bottom to top in the absorption tube 11, different thrusts in different directions will be generated on the disturbing ball 124 on the inner wall 116 of the absorption tube, and the change in the size of the different thrusts will bring the disturbing ball 124 to move within a certain range, so that the disturbing ball 124 disturbs and stirs the liquid in the absorption tube 11, increases the reaction and dissolution of the tail gas in the absorption liquid.

[0065] The presence of the disturbing unit 12 on the inner wall of the absorption tube 11 increases the flow resistance of the liquid and gas in the absorption tube 11 and increases the contact time of the gas and the liquid, which is further beneficial to the absorption of the tail gas by the absorption liquid.

[0066] As an optimization, a buffer tank 18 is further provided, and the inlet of the buffer tank 18 is connected to the liquid inlet pipe 17 through the liquid inlet branch pipe 171, and the outlet is connected to the second end of the absorption tube 11 through the liquid outlet pipe 182.

[0067] As a specific example, the upper part of the buffer tank 18 is provided with an inlet connected to the liquid inlet branch pipe 171, and the liquid outlet pipe 182 is arranged at the bottom end of the side of the buffer tank 18. The liquid outlet pipe 182 is inclined as a whole, and the end connected to the buffer tank 18 is higher than the end connected to the absorption tube 11, which facilitates the liquid to flow from the buffer tank 18 to the absorption tube 11 under the action of gravity, thereby reducing the power cost.

[0068] As Figures 4-7 , the outlet of the buffer tank 18 is provided with a movable valve 181.

[0069] The upper end of the movable valve 181 is connected and fixed to the side wall of the buffer tank 18 through a rotating shaft 183, and the movable valve 181 can rotate around the rotating shaft 183. The lower end of the movable valve 181 is provided with a first magnetic block 184, and the buffer tank bottom plate 186 is provided with a second magnetic block 185 corresponding to the lower end of the movable valve 181. The first magnetic block 184 and the second magnetic block 185 are magnetically adsorbed to achieve the closing of the movable valve 181, and the magnetic adsorption force is equal to the self-gravity when the absorption liquid in the buffer tank 18 reaches the set liquid level.

[0070] When there is no liquid in the buffer tank 18, the movable valve 181 rotates to the vertical state under its own gravity, and the first magnetic block 184 and the second magnetic block 185 are attracted by the magnetic force, so the movable valve 181 is closed. When the liquid in the buffer tank 18 gradually increases, before the liquid surface reaches the set maximum liquid level, the liquid gravity in the buffer tank 18 is less than the magnetic attraction force between the first magnetic block 184 and the second magnetic block 185, so the movable valve 181 will not open; when the liquid surface in the buffer tank 18 exceeds the set liquid level, the liquid gravity in the buffer tank 18 is greater than the magnetic attraction force between the first magnetic block 184 and the second magnetic block 185, so the movable valve 181 opens, and the liquid in the buffer tank 18 is discharged.

[0071] During the liquid discharge process, the first magnetic block 184 and the second magnetic block 185 are far away from each other due to the impact force of continuous liquid discharge and the rotation angle of the movable valve 181, so they are not within the magnetic attraction range of each other, and thus the first magnetic block 184 and the second magnetic block 185 will not be attracted together during the liquid discharge process.

[0072] When the liquid discharge is completed, the movable valve 181 rotates to the vertical state under its own gravity, and the first magnetic block 184 reaches the magnetic attraction range of the second magnetic block 185, so the first magnetic block 184 on the movable valve 181 is captured by the magnetic force of the second magnetic block 185 on one end of the buffer tank bottom plate 186. The first magnetic block 184 and the second magnetic block 185 are attracted to each other, and thus the movable valve 181 is closed. At this time, the liquid surface in the buffer tank 18 rises again, and the liquid begins to be buffered.

[0073] When the liquid surface in the buffer tank 18 reaches the set liquid level again, the above process is repeated, and the movable valve 181 opens again to discharge the liquid.

[0074] In summary, the opening and closing state of the movable valve 181 is controlled by the liquid level of the absorbed liquid in the buffer tank 18. When the liquid level in the buffer tank 18 is lower than the set liquid level, the amount of liquid in the buffer tank 18 is small, and the gravity generated by the liquid is small, so the pressure acting on the movable valve 181 at the bottom of the buffer tank 18 is small, which is not enough to open the movable valve 181; when the liquid level in the buffer tank 18 reaches the set liquid level, the amount of liquid in the buffer tank 18 reaches a certain value, and at this time the gravity generated by the liquid in the buffer tank 18 acts on the movable valve 181 below to reach a certain value. After the movable valve 181 is subjected to the thrust, it opens in the direction of the liquid discharge pipe 182, and the liquid in the buffer tank 18 flows into the absorption pipe 11 through the liquid discharge pipe 182.

[0075] The liquid inlet branch pipe 171 supplies the absorption liquid to the buffer tank 18, and the buffer tank 18 does not discharge liquid into the absorption pipe 11 until the liquid level in the buffer tank 18 reaches the set liquid level. At this time, the absorption liquid in the absorption pipe 11 is supplied stably from the liquid inlet pipe 17 and the reflux pipe 14. When the fluid pressure between the liquid in the absorption pipe 11 and the gas entering from the lower end of the absorption pipe 11 reaches a dynamic balance, the activity of the disturbance ball 124 is not conducive to the mixing absorption of the tail gas and the absorption liquid.

[0076] As the liquid inlet branch pipe 171 continuously supplies the absorption liquid to the buffer tank 18, when the liquid level of the absorption liquid in the buffer tank 18 reaches the set liquid level, the buffer tank 18 starts to discharge the absorption liquid into the absorption pipe 11. At this time, the absorption liquid entering the absorption pipe 11 breaks the dynamic balance of the gas and the liquid in the absorption pipe 11 before, and the pressure balance state of the disturbance ball 124 is broken, the disturbance ball 124 moves in the absorption pipe 11, realizes the stirring of the liquid in the absorption pipe 11, and enhances the absorption effect of the tail gas.

[0077] When the liquid and the gas in the absorption pipe 11 are about to reach a dynamic balance, the buffer tank 18 discharges liquid into the absorption pipe 11 again, breaking the above-mentioned dynamic balance again, that is, additional absorption liquid enters the absorption pipe 11 every certain period of time, so that the gas and the liquid in the absorption pipe 11 are continuously stirred. In this way, the absorption rate of the tail gas in the absorption liquid is improved.

[0078] Since the absorption liquid needs a certain time to reach the set liquid level in the buffer tank 18 to open the movable valve 181, in consideration of the simplification of the device, no valve can be arranged on the liquid inlet branch pipe 171.

[0079] The set liquid level can be obtained by experiment, or can be calculated comprehensively according to the size and magnetic strength of the two magnetic blocks and the inner diameter of the buffer tank 18.

[0080] In addition, after the liquid gravity in the buffer tank 18 is greater than the suction force of the two magnetic blocks, the two magnetic blocks will be separated, and the buffer tank 18 starts to discharge liquid. Therefore, in order to simplify the device and the system, the system can not need to set the liquid level by program, and can automatically realize the discharge of the buffer tank 18 by continuously raising the liquid level until the liquid gravity is greater than the suction force of the magnetic blocks.

[0081] In other cases, a valve can also be arranged, and the speed of the absorption liquid entering the buffer tank 18 can be adjusted by controlling the opening and closing size of the valve through the control system.

[0082] Embodiment 2

[0083] A tail gas treatment method based on the tail gas treatment device for producing methylamine described in Embodiment 1 is provided.

[0084] The method for treating the methylamine production tail gas comprises the following steps:

[0085] Step 1, check the connection state of the methylamine production tail gas treatment device to ensure no gas leakage or liquid leakage;

[0086] Step 2, close the control valve 152 in front of the recovery liquid storage tank 15;

[0087] Step 3, introduce the absorption liquid through the liquid inlet pipe 17, part of the absorption liquid enters the absorption pipe 11 through the liquid inlet pipe 17, and part of the absorption liquid enters the buffer tank 18 through the liquid inlet branch pipe 171, and the absorption liquid gradually fills the absorption pipe 11;

[0088] Step 4, when the absorption liquid reaches the lower recovery pipe 151, start the pressure pump 16 to send the absorption liquid flowing into the recovery pipe 151 into the return pipe 14 through the pressure pump 16, and then into the upper liquid inlet pipe 17 and into the absorption pipe 11 again to form a cycle;

[0089] Step 5, send the tail gas to be treated into the absorption pipe 11 through the gas inlet pipe 13 to start absorbing the tail gas;

[0090] Step 6, while the tail gas is sent into the absorption pipe 11, open the control valve 152 in front of the recovery liquid storage tank 15 to recover the absorption liquid after absorbing the tail gas.

[0091] Through the above steps, the absorption liquid enters the absorption pipe 11 through the liquid inlet pipe 17, absorbs the tail gas, part of the liquid flows to the recovery liquid storage tank 15 for recovery, and part of the liquid is sent into the absorption pipe 11 again through the pressure pump 16 to fully and cyclically absorb the tail gas. The proportion of recovery can be controlled by the size of the control valve 152 in front of the recovery liquid storage tank 15. The buffer tank 18 supplements the absorption liquid into the absorption pipe 11 at intervals, breaks the gas-liquid pressure dynamic balance in the absorption pipe 11, drives the disturbance unit 12 on the inner wall 116 of the absorption pipe to disturb and stir, and further promotes the absorption liquid to fully absorb the tail gas.

[0092] Example 3

[0093] The difference from Example 1 is that the buffer tank 18 and the liquid inlet branch pipe 171 are not provided, and the others remain the same.

[0094] The gas inlet flow and pressure of the gas inlet pipe 13 are controlled to change discontinuously to break the pressure balance of the gas and liquid in the absorption pipe 11 and drive the disturbance ball 124 to act.

[0095] Example 4

[0096] The difference from Example 1 is that the buffer tank 18 and the liquid inlet branch pipe 171 are not provided, and the others remain the same.

[0097] By controlling the liquid inlet flow rate and speed of the liquid inlet pipe 11, the pressure balance of the gas and liquid in the absorption pipe is broken, and the disturbance ball 124 is driven to move.

[0098] Although examples 3 and 4 need to increase additional equipment and program control relative to example 1, the equipment cost and control operation cost are increased, but they are also superior to the prior art device, and the basic beneficial effects of the present application can be achieved.

[0099] Although the embodiments disclosed by the present application are as above, the content described is only for the purpose of understanding the embodiments adopted by the present application, and is not intended to limit the present application. Any person skilled in the art of the present application can make any modification and change in the form and details without departing from the spirit and scope of the present application disclosed, but the patent protection scope of the present application shall be subject to the scope defined by the appended claims.

Claims

1. A device for treating exhaust gas from methylamine production, comprising an absorption tube (11), an inlet pipe (13), a storage tank (15) for recovery liquid, a return pipe (14) and a liquid inlet pipe (17), the inlet pipe (13) being connected to an exhaust gas discharge device of a methylamine production system, the liquid inlet pipe (17) being connected to a supply device for absorption liquid, the first end of the absorption tube (11) being connected to the inlet pipe (13) and the second end being connected to the liquid inlet pipe (17), the first end of the absorption tube (11) being provided with a plurality of absorption tube peaks and absorption tube valleys in a gradually ascending manner from the first end to the second end, and the second end of the absorption tube (11) being provided with an exhaust gas outlet (115) at a position higher than the upper portion connected to the liquid inlet pipe (17); the first end of the absorption tube (11) being connected to the storage tank (15) through a return pipe (151) provided with a control valve (152), the return pipe (151) being connected to the liquid inlet pipe (17) through the return pipe (14) provided with a pressure pump (16); the connection between the inlet pipe (13) and the absorption tube (11) being provided with a movable plate (131), the upper end of the movable plate (131) being rotatably connected to the highest portion of the outlet of the inlet pipe (13) and being capable of rotating in a unidirectional manner towards the inside of the absorption tube (11), the lower end of the movable plate (131) extending vertically downwards and being capable of shielding the outlet of the inlet pipe (13), and a gap being formed between the lower edge of the movable plate (131) and the outlet of the inlet pipe (13) and serving as an inlet (132); a plurality of disturbance units (12) for disturbing and stirring the absorption liquid in the absorption tube (11) being provided on the inner wall (116) of the absorption tube (11), the disturbance units (12) being driven by liquid or gas entering or exiting the absorption tube (11); the disturbance unit (12) comprising a fixing member (121), a connecting member (122), a connecting rod (123) and a disturbance ball (124), the fixing member (121) being fixed on the inner wall (116) of the absorption tube (11), the connecting member (122) being rotatably connected to the fixing member (121), one end of the connecting rod (123) being connected to the connecting member (122) and the other end being connected to the disturbance ball (124); the device further comprising a buffer tank (18), the inlet of the buffer tank (18) being connected to the liquid inlet pipe (17) through a liquid inlet branch pipe (171) and the outlet being connected to the second end of the absorption tube (11) through a liquid outlet pipe (182); the outlet of the buffer tank (18) being provided with a movable valve (181), the upper end of the movable valve (181) being connected to the side wall of the buffer tank (18) through a rotating shaft (183), the lower end of the movable valve (181) being provided with a first magnetic block (184), and the bottom plate (186) of the buffer tank being provided with a second magnetic block (185) at a position close to the lower end of the movable valve (181); the opening and closing state of the movable valve (181) being controlled by adjusting the amount of absorption liquid entering the buffer tank (18) to control the magnetic adsorption between the first magnetic block (184) and the second magnetic block (185).

2. The apparatus for treating methylamine production tail gas according to claim 1, characterized by, The rising section of each absorption tube peak is longer than the corresponding falling section, and the first absorption tube peak, the first absorption tube valley, the second absorption tube peak, the second absorption tube valley, the third absorption tube peak and the third absorption tube valley are arranged in sequence from the first end of the absorption tube (11) to the second end of the absorption tube (11) in the direction of the rising section of the first absorption tube peak.

3. The apparatus for treating methylamine production tail gas according to claim 2, characterized by, The peak top (111) of the absorption tube peak is a horizontal structure, and the peak bottom (112) of the absorption tube peak, the valley top (113) and the valley bottom (114) of the absorption tube valley are all arc structures.

4. A method for treating a methylamine production tail gas, characterized by, The processing device according to any one of claims 1-3 is used for processing.

5. The method of treating a methylamine production tail gas according to claim 4, wherein The method comprises the following steps: Step 1: checking the connection state of the processing device of the methylamine production tail gas to ensure that there is no gas leakage or liquid leakage phenomenon; Step 2: closing the control valve (152); Step 3: introducing the absorption liquid through the liquid inlet pipe (17), so that part of the absorption liquid enters the absorption tube (11) through the liquid inlet pipe (17), and the other part of the absorption liquid enters the buffer tank (18) arranged between the absorption tube (11) and the liquid inlet pipe (17) through the liquid inlet branch pipe (171); Step 4: starting the pressure pump (16) when the absorption liquid reaches the recovery pipe (151), and sending the absorption liquid flowing into the recovery pipe (151) into the backflow pipe (14) through the pressure pump (16) and then into the liquid inlet pipe (17) and the absorption tube (11) again to form a cycle; Step 5: sending the tail gas to be treated into the absorption tube (11) through the gas inlet pipe (13) to start absorbing the tail gas; Step 6: opening the back control valve (152) while sending the tail gas into the absorption tube (11) to recover the absorption liquid after absorbing the tail gas.

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