Ammonia Oxidizer for an Exhaust Gas Ammonia Removal System

Abstract

The present invention discloses an ammonia oxidizer for a tail gas ammonia removal system. By installing a deflector inside a reaction chamber having an intake pipe and an outlet pipe, which can enable the gas to circulate repeatedly inside the reaction chamber, and at the same time arranging a catalyst for catalytic combustion reaction in the necessary path of the gas circulating repeatedly, a combustion chamber that is not affected by the gas flow rate and velocity is obtained by alternately opening and closing the intake pipe and the outlet pipe. At the same time, the present invention also discloses an ammonia oxidation method for a tail gas ammonia removal system. By allowing ammonia to circulate repeatedly inside the reaction chamber to pass through the catalyst for catalytic combustion reaction repeatedly, the catalytic combustion efficiency of ammonia is improved. At the same time, waste gas is discharged when the internal pressure of the reaction chamber rises to a threshold value. At this time, the internal pressure of the reaction chamber is relatively high, and a bursting airflow will be generated instantaneously at the outlet pipe. The bursting airflow flushes out the impurities adsorbed on the catalyst to clean the catalyst.

Description

Technical Field

[0001] The present invention relates to the field of waste gas combustion treatment in the presence of a catalyst, and particularly to an ammonia oxidizer for a tail gas ammonia removal system. Background Art

[0002] In the field of the chemical industry, ammonia is usually treated through catalytic combustion reactions. However, ammonia has the characteristics of a large emission volume, unstable flow rate and concentration, being discharged and treated at any time, and high treatment requirements. Therefore, achieving deep removal of low-concentration ammonia is a challenge in this field.

[0003] In existing equipment, ammonia is usually discharged into the atmosphere without being fully catalytically combusted, which is caused by the catalytic performance of the catalyst being affected by various factors.

[0004] The catalytic performance is affected by ammonia concentration, catalytic temperature and space velocity. Complete catalytic combustion of the reaction requires a relatively high concentration of ammonia, an appropriate catalytic temperature and a low space velocity.

[0005] Chinese Patent Publication No. CN108421369A discloses an organic waste gas treatment device provided with a mobile desorption catalytic combustion vehicle, which discloses a treatment system that uses activated carbon to adsorb low-concentration ammonia, and after its adsorption saturation, desorbs the ammonia and then conducts combustion. It can provide ammonia with a stable concentration to the combustion chamber and a stable catalytic temperature provided by the combustion chamber.

[0006] However, the instability of the emission flow rate and velocity of the tail gas remains an unsolved problem. When the velocity of the tail gas is relatively fast, a part of the ammonia in the tail gas is carried away from the combustion chamber before fully contacting the catalyst, resulting in incomplete catalytic reaction.

[0007] Moreover, the tail gas contains a large amount of impurities. Even if the tail gas is filtered and cleaned in advance, it is inevitable that some fine impurities will enter the combustion chamber, gradually causing blockage of the catalyst and affecting the flow of ammonia through the catalyst. Summary of the Invention

[0008] The purpose of the present invention is to provide an ammonia oxidizer for a tail gas ammonia removal system to solve the technical problem of how to enable it to be fully catalytically combusted when the flow rate of ammonia is unstable. At the same time, it also solves the technical problem that the tail gas carries fine impurities, and the impurities gradually block the ammonia catalyst.

[0009] To solve the above technical problems, the present invention specifically provides the following technical solutions:

[0010] The present application provides an ammonia oxidizer for an exhaust gas ammonia removal system, including a reaction chamber; a catalyst disposed in the middle of the reaction chamber and partitioning the interior of the reaction chamber into a first chamber and a second chamber, the catalyst being a grid structure; an intake pipe communicating with the interior of the reaction chamber and used for introducing exhaust gas containing high-concentration ammonia into the reaction chamber; a heater disposed in the interior of the reaction chamber and used for raising the temperature inside the reaction chamber so that the interior of the reaction chamber has an initial temperature for catalytic combustion reaction of ammonia; an outlet pipe communicating with the interior of the reaction chamber and used for discharging ammonia after catalytic combustion reaction; a flow deflector disposed in the interior of the reaction chamber and guiding the gas flow inside the reaction chamber to circulate reciprocally between the first chamber and the second chamber; and a valve group for alternately opening and closing the intake pipe and the outlet pipe, so that when the intake pipe is open, the outlet pipe is closed, and when the outlet pipe is open, the intake pipe is closed.

[0011] Further, the flow deflector includes a vortex fan, the fan blades of the vortex fan are disposed inside the second chamber and face the intake pipe, and the vortex fan is used for axially sucking in gas and radially discharging gas, so that the gas inside the first chamber passes through the catalyst along the center of the reaction chamber and enters the second chamber, then flows along the wall surface of the reaction chamber and passes through the catalyst again to enter the first chamber.

[0012] As another aspect of the present application, the flow deflector includes a Venturi tube, the Venturi tube is disposed inside the first chamber and coaxially connected to the intake pipe, the outlet end of the Venturi tube faces the catalyst, and a through hole is provided in the throat of the Venturi tube; when the intake pipe is open, the gas inside the first chamber is sucked into the Venturi tube through the through hole and passes through the catalyst to flow to the second chamber, then flows along the inner wall of the reaction chamber and passes through the catalyst again to flow to the first chamber.

[0013] Further, a temperature sensor is provided on the catalyst, the temperature sensor is used for detecting the temperature of the catalyst, and when the temperature of the catalyst drops to near the temperature at which catalytic combustion reaction of ammonia occurs, the valve group opens the intake pipe and closes the outlet pipe.

[0014] Further, a pressure sensor is disposed inside the reaction chamber, the pressure sensor is used for detecting the air pressure inside the reaction chamber, and when the air pressure inside the reaction chamber rises to a threshold value, the valve group opens the outlet pipe and closes the intake pipe.

[0015] Further, the outlet pipe is sleeved outside the intake pipe.

[0016] Further, the valve group includes a ninth stop valve, a tenth stop valve and a driver. The ninth stop valve includes a first valve core capable of blocking the air outlet pipe, and the tenth stop valve includes a second valve core capable of blocking the air inlet pipe. The first valve core and the second valve core are fixedly connected to the actuator of the driver through the connecting member.

[0017] Further, the driver is arranged inside the air inlet pipe.

[0018] Further, the air outlet pipe is separated from the air inlet pipe at a position close to the driver.

[0019] The present application also provides an ammonia oxidation method for a tail gas ammonia removal system, including the following steps: S1, obtaining a reaction chamber with an air inlet pipe and an air outlet pipe, installing a deflector inside the reaction chamber capable of making the gas circulate reciprocally inside the reaction chamber, and arranging a catalyst for catalytic combustion reaction on the necessary path for the gas to circulate reciprocally; S2, increasing the temperature inside the reaction chamber so that the inside of the reaction chamber has an initial temperature for the catalytic combustion reaction of ammonia to occur; S3a, when the temperature inside the reaction chamber drops to close to the initial temperature of the catalytic combustion reaction, opening the air inlet pipe and closing the air outlet pipe, and introducing tail gas containing high-concentration ammonia into the reaction chamber through the air inlet pipe. The ammonia circulates reciprocally inside the reaction chamber to repeatedly pass through the catalyst for catalytic combustion reaction; S3b, when the air pressure inside the reaction chamber rises to the threshold value, closing the air inlet pipe and opening the air outlet pipe, and the ammonia that has fully undergone the catalytic combustion reaction leaves the reaction chamber through the air outlet pipe.

[0020] The present application has the following beneficial effects compared with the prior art:

[0021] An ammonia oxidizer for a tail gas ammonia removal system is provided. By installing a deflector inside a reaction chamber with an air inlet pipe and an air outlet pipe capable of making the gas circulate reciprocally inside the reaction chamber, and at the same time arranging a catalyst for catalytic combustion reaction on the necessary path for the gas to circulate reciprocally, a combustion chamber that is not affected by the gas flow rate and velocity is obtained by alternately opening and closing the air inlet pipe and the air outlet pipe.

[0022] An ammonia oxidation method for a tail gas ammonia removal system is provided. By opening the air inlet pipe and closing the air outlet pipe, the ammonia circulates reciprocally inside the reaction chamber to repeatedly pass through the catalyst for catalytic combustion reaction, improving the catalytic combustion efficiency of ammonia. At the same time, when the air pressure inside the reaction chamber rises to the threshold value, the air inlet pipe is closed and the air outlet pipe is opened, and the ammonia that has fully undergone the catalytic combustion reaction leaves the reaction chamber through the air outlet pipe. At this time, the air pressure inside the reaction chamber is relatively high, and a burst airflow will be generated at the moment of the air outlet pipe. The burst airflow flushes out the impurities adsorbed on the catalyst to clean the catalyst. Description of the Drawings

[0023] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary. For those of ordinary skill in the art, without creative efforts, other implementation drawings can also be obtained based on the provided drawings.

[0024] Figure 1 Structural schematic diagram of the first embodiment of the ammonia oxidizer of the present invention;

[0025] Figure 2 Schematic diagram of a working state of the first embodiment of the ammonia oxidizer of the present invention;

[0026] Figure 3 Another schematic diagram of a working state of the first embodiment of the ammonia oxidizer of the present invention;

[0027] Figure 4 Structural schematic diagram of a working state of the second embodiment of the ammonia oxidizer of the present invention;

[0028] Figure 5 Structural schematic diagram of another working state of the second embodiment of the ammonia oxidizer of the present invention;

[0029] Figure 6 System diagram of the tail gas ammonia removal system of the embodiment of the present invention;

[0030] The reference numerals in the figure respectively represent the following:

[0031] 1 - Filter box;

[0032] 2 - Adsorption device; 21 - Flame arrester; 22 - First adsorption box; 221 - First adsorption bed; 222 - First stop valve; 223 - Second stop valve; 224 - Third stop valve; 225 - Fourth stop valve; 23 - Second adsorption box; 231 - Second adsorption bed; 232 - Fifth stop valve; 233 - Sixth stop valve; 234 - Seventh stop valve; 235 - Eighth stop valve;

[0033] 3 - Desorption device;

[0034] 4 - Ammonia oxidizer; 41 - Reaction chamber; 411 - Intake pipe; 412 - Outlet pipe; 42 - Catalyst; 43 - Heater; 44 - Eddy current fan; 45 - Ninth stop valve; 46 - Venturi tube; 461 - Through hole; 47 - Tenth stop valve; 48 - Connector; 49 - Driver;

[0035] 5 - Air induction device; 51 - Air induction device; 52 - Three - way valve;

[0036] 6 - Exhaust device;

[0037] 7 - Cold - supplementing fan;

[0038] 8 - Controller. Specific embodiments

[0039] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

[0040] Since the flow rate of the tail gas fluctuates greatly, the desorbed tail gas discharged through the combustion chamber inevitably contains ammonia that has not participated in the catalytic combustion reaction. To solve this problem, as shown in FIGS. Figure 1 , 2 , 3, an ammonia oxidizer 4 is provided, and its specific structure is described as follows.

[0041] The ammonia oxidizer of the tail - gas ammonia - removing system includes a reaction chamber 41, a catalyst 42, an intake pipe 411, an outlet pipe 412, a heater 43, a deflector, and a valve group.

[0042] The catalyst 42 is arranged in the middle of the reaction chamber 41 and divides the interior of the reaction chamber 41 into a first chamber and a second chamber. The catalyst 42 is a grid structure;

[0043] The intake pipe 411 is connected to the first chamber and is used to introduce the tail gas containing high - concentration ammonia into the reaction chamber 41;

[0044] The heater 43 is arranged in the second chamber and is used to raise the temperature inside the reaction chamber 41 so that the interior of the reaction chamber 41 has an initial temperature for the catalytic combustion reaction of ammonia;

[0045] The outlet pipe 412 is connected to the first chamber and is used to discharge the ammonia after the catalytic combustion reaction;

[0046] The deflector is arranged inside the reaction chamber 41 and guides the airflow inside the reaction chamber 41 to circulate reciprocally between the first chamber and the second chamber;

[0047] The valve group is used to alternately open and close the intake pipe 411 and the outlet pipe 412, so that when the intake pipe 411 is open, the outlet pipe 412 is closed, and when the outlet pipe 412 is open, the intake pipe 411 is closed.

[0048] Specifically:

[0049] The reaction chamber 41 is a high - temperature - resistant housing made of ceramics.

[0050] The catalyst 42 is a metal grid with a platinum-rhodium-palladium ternary alloy as the main body.

[0051] The heater 43 is a gas nozzle. The heater 43 is used to inject combustible gas into the reaction chamber 41 and ignite it to raise the temperature inside the reaction chamber 41. The heater 43 can also be an electric heating device.

[0052] In the first working condition, the valve group opens the intake pipe 411 and closes the outlet pipe 412. The ammonia gas injected into the reaction chamber 41 through the intake pipe 411 repeatedly passes through the catalyst 42 to fully carry out the catalytic combustion reaction.

[0053] In the second working condition, the valve group closes the intake pipe 411 and opens the outlet pipe 412. The ammonia gas that has fully undergone the catalytic combustion reaction leaves the reaction chamber 41 through the outlet pipe 412. At this time, the air pressure inside the reaction chamber 41 is relatively high, and a burst of air flow will be generated at the moment of the outlet pipe 412. The burst of air flow can wash out the impurities adsorbed on the catalyst 42 to clean the catalyst 42 and prevent it from being blocked.

[0054] The switching between the first working condition and the second working condition can be determined according to the reaction time, flame size, or flame temperature of the catalytic combustion reaction.

[0055] As Figure 2 、 3 shown, the following provides a first embodiment of the ammonia oxidizer 4, and its specific structure is described as follows.

[0056] The flow guide device includes a vortex fan 44. The fan blades of the vortex fan 44 are arranged inside the second chamber and are directly opposite to the intake pipe 411. The vortex fan 44 is used to axially suck in gas and radially discharge gas, so that the gas inside the first chamber passes through the catalyst 42 along the center of the reaction chamber 41 and enters the second chamber, and then flows along the wall surface of the reaction chamber 41 and passes through the catalyst 42 again to enter the first chamber.

[0057] The vortex fan 44 includes a motor and vortex fan blades installed on the motor shaft. In the figure, only the motor shaft of the motor is shown for illustration. The motor is installed in the tail gas passage, and the motor is cooled by the normal-temperature tail gas passage to prevent the high temperature inside the reaction chamber 41 from being conducted to the motor and causing the motor to be damaged due to high temperature.

[0058] Under the action of the vortex fan blades, the gas at the center of the reaction chamber 41 passes through the catalyst 42 and flows towards the vortex fan blades, and then is radially discharged by the vortex fan blades and flows along the inner wall of the reaction chamber 41, and then passes through the catalyst 42 again and returns to the center of the reaction chamber 41. The gas that circulates repeatedly inside the reaction chamber 41 passes through the catalyst 42 many times, so that the ammonia gas undergoes the catalytic combustion reaction many times.

[0059] When the air pressure inside the reaction chamber 41 is relatively high, the intake pipe 411 is closed and the outlet pipe 412 is opened. The desorption tail gas that has undergone multiple catalytic combustion reactions is discharged through the outlet pipe 412.

[0060] Optionally:

[0061] As Figure 4 、 5 shown, the following provides a second embodiment of the ammonia oxidizer 4, and its specific structure is described as follows.

[0062] The flow guide includes a Venturi tube 46. The Venturi tube 46 is arranged inside the first chamber and coaxially connected to the intake pipe 411. The outlet end of the Venturi tube 46 faces the catalyst 42, and a through hole 461 is provided in the throat of the Venturi tube 46;

[0063] When the intake pipe 411 is opened, the gas inside the first chamber is sucked into the Venturi tube 46 through the through hole 461, flows through the catalyst 42 to the second chamber, and then flows along the inner wall of the reaction chamber 41 and through the catalyst 42 again to the first chamber.

[0064] The desorption tail gas is sprayed into the reaction chamber 41 through the intake pipe 411. The high-speed flowing desorption tail gas passes through the catalyst 42 and reaches the top of the reaction chamber 41. Then the desorption tail gas flows reversely along the inner wall of the reaction chamber 41 and passes through the catalyst 42 again.

[0065] When the desorption tail gas passes through the throat of the Venturi tube 46, it accelerates and generates a negative pressure, so that the throat of the Venturi tube 46 sucks in the desorption tail gas through the through hole 461, and then sprays it out again through the outlet end of the Venturi tube 46. As long as the intake pipe 411 is still inputting desorption tail gas into the reaction chamber 41, the desorption tail gas inside the reaction chamber 41 will continuously circulate and pass through the catalyst 42 multiple times to participate in the catalytic combustion reaction.

[0066] When the air pressure inside the reaction chamber 41 is relatively high, the intake pipe 411 is closed and the outlet pipe 412 is opened. The desorption tail gas that has undergone multiple catalytic combustion reactions is discharged through the outlet pipe 412.

[0067] Furthermore:

[0068] The valve group can alternately open and close the intake pipe 411 and the outlet pipe 412 according to the timer built in the controller 800, or the timing of the alternation can be determined by the following technical means.

[0069] A temperature sensor is provided on the catalyst 42. The temperature sensor is used to detect the temperature of the catalyst 42. When the temperature of the catalyst 42 drops to near the temperature at which the catalytic combustion reaction of ammonia occurs, the valve group opens the intake pipe 411 and closes the outlet pipe 412.

[0070] When the ammonia undergoes a catalytic combustion reaction, the temperature of the catalyst 42 gradually increases. After the ammonia reaction is completed, the temperature of the catalyst 42 gradually decreases. Before the temperature of the catalyst 42 drops below the initial temperature at which the ammonia undergoes a catalytic combustion reaction, the controller 800 manipulates the valve group to open the intake pipe 411 to output high-concentration ammonia to the catalyst 42, so as to restart the catalytic combustion reaction of ammonia, thereby eliminating the need to restart the heater 43 to save fuel.

[0071] A pressure sensor is provided inside the reaction chamber 41. The pressure sensor is used to detect the air pressure inside the reaction chamber 41. The valve group opens the outlet pipe 412 and closes the intake pipe 411 when the air pressure inside the reaction chamber 41 rises to a threshold value.

[0072] The threshold value refers to the maximum safe air pressure that the inside of the reaction chamber 41 and the intake pipe 411 can withstand.

[0073] Furthermore:

[0074] Even though the ammonia oxidizer 4 can perform a self-sustaining catalytic combustion reaction through the heat generated by ammonia combustion without additional fuel supplementation, however, this is only limited to the premise of a relatively high ammonia concentration. As the ammonia inside the adsorption device 2 gradually desorbs, the concentration of ammonia input into the ammonia oxidizer 4 gradually decreases, which causes the temperature inside the reaction chamber 41 to gradually decrease accordingly, and ultimately results in the end of the self-sustaining catalytic combustion reaction, leading to a short reaction time, or the need for the heater 43 to operate to heat the temperature inside the reaction chamber 41, resulting in a large energy consumption.

[0075] Therefore, an alternative embodiment for solving the above technical problems is provided, and its specific structure is described as follows.

[0076] The outlet pipe 412 is sleeved outside the intake pipe 411.

[0077] The intake pipe 411 and the outlet pipe 412 form a heat exchanger. The high-temperature desorption tail gas output through the outlet pipe 412 heats the intake pipe 411, so that the low-temperature desorption tail gas inside the intake pipe 411 is preheated and then enters the reaction chamber 41 to participate in the catalytic combustion reaction. At the same time, the high-temperature desorption tail gas inside the outlet pipe 412 is cooled and then discharged through the smoke exhaust device 6.

[0078] The intake pipe 411 can adopt a number of capillary pipes, thereby increasing the contact area between the intake pipe 411 and the outlet pipe 412 to improve the heat exchange efficiency between the two.

[0079] Furthermore:

[0080] The valve group includes a ninth stop valve 45, a tenth stop valve 47 and a driver 49. The ninth stop valve 45 includes a first valve core capable of blocking the air outlet pipe 412, and the tenth stop valve 47 includes a second valve core capable of blocking the air inlet pipe 411. The first valve core and the second valve core are fixedly connected to the actuator of the driver 49 through a connecting member 48.

[0081] The connecting member 48 is visible in Figure 1 In order to facilitate observing the air flow direction inside the reaction chamber 41, Figures 2 to 5 the connecting member 48 in

[0082] has been hidden. The ninth stop valve 45 uses the pipe body of the air outlet pipe 412 close to its own air inlet as the valve housing, and the tenth stop valve 47 uses the pipe body of the air inlet pipe 411 close to its own air outlet as the valve housing. The first valve core and the second valve core act synchronously through the connecting member 48, so that when one of the air inlet pipe 411 and the air outlet pipe 412 is opened, the other is closed.

[0083] The driver 49 can be a cylinder, an electric push rod or an electromagnetic push rod. The driver 49 is used to drive the connecting member 48 to move, so that the first valve core and the second valve core perform the actions of opening or closing the air outlet pipe 412 and the air inlet pipe 411.

[0084] Furthermore:

[0085] Since the high temperature inside the reaction chamber 41 is easily conducted to the driver 49 through the first valve core, the second valve core and the connecting member 48, causing the driver 49 to be damaged by high temperature.

[0086] Therefore, the driver 49 is arranged inside the air inlet pipe 411.

[0087] The gas flowing inside the air inlet pipe 411 is normal temperature tail gas. The normal temperature tail gas can produce an air cooling effect on the driver 49 and the connecting member 48, so as to avoid the temperature of the connecting member 48 being too high and keep the driver 49 at a suitable working temperature all the time.

[0088] Moreover, the air outlet pipe 412 is separated from the air inlet pipe 411 at a position close to the driver 49.

[0089] The driver 49 is located outside the air outlet pipe 412. The normal temperature tail gas near the driver 49 does not participate in heat exchange, avoiding the driver 49 being heated by the normal temperature tail gas that has participated in heat exchange and increased in temperature.

[0090] The ammonia oxidation method of the ammonia oxidizer in the tail gas deammoniation system includes the following steps:

[0091] S1. Obtain a reaction chamber with an intake pipe and an outlet pipe. Install a deflector inside the reaction chamber that can make the gas flow cyclically within the reaction chamber, and set the catalyst for catalytic combustion reaction in the necessary path of the cyclic gas flow.

[0092] S2. Raise the temperature inside the reaction chamber so that the inside of the reaction chamber has an initial temperature for the catalytic combustion reaction of ammonia.

[0093] S3a. When the temperature inside the reaction chamber drops to near the initial temperature of the catalytic combustion reaction, open the intake pipe and close the outlet pipe, and introduce the tail gas containing high-concentration ammonia into the reaction chamber through the intake pipe. The ammonia flows cyclically within the reaction chamber to repeatedly pass through the catalyst for catalytic combustion reaction.

[0094] S3b. When the air pressure inside the reaction chamber rises to the threshold value, close the intake pipe and open the outlet pipe, and the ammonia that has fully undergone the catalytic combustion reaction leaves the reaction chamber through the outlet pipe.

[0095] As Figure 6 shown, the application of the ammonia oxidizer is also provided, which is applied to the tail gas ammonia removal system. The main structure of the tail gas ammonia removal system includes:

[0096] A filter box 1, an ammonia concentrator, an ammonia oxidizer 4, and a smoke exhaust device 6 connected through a tail gas channel;

[0097] An air guiding device 5, which is used to generate the power for the tail gas to flow in the tail gas channel so that the tail gas sequentially passes through the filter box 1, the ammonia concentrator, and the smoke exhaust device 6, or so that the tail gas sequentially passes through the filter box 1, the ammonia concentrator, the ammonia oxidizer 4, and the smoke exhaust device 6, or so that the tail gas circulates through the ammonia concentrator and the ammonia oxidizer 4;

[0098] Among them:

[0099] The filter box 1 is used to connect to the tail gas source and filter the dust particles in the tail gas;

[0100] The ammonia concentrator includes an adsorption device 2 and a desorption device 3. The adsorption device 2 is used to adsorb ammonia in the tail gas, and the desorption device 3 is used to desorb ammonia when the adsorption device 2 is saturated, so as to generate desorption tail gas formed by the mixture of high-concentration ammonia and tail gas;

[0101] The ammonia oxidizer 4 is used to heat the desorption tail gas and provide a space for the catalytic combustion reaction of the high-concentration ammonia in the desorption tail gas;

[0102] The smoke exhaust device 6 is used to discharge the desorption tail gas that has undergone catalytic combustion.

[0103] The structure provided by the above embodiment is executed by the following method:

[0104] After the tail gas is filtered by the filter box 1 to remove dust particles, it is introduced into the ammonia concentrator. The low-concentration ammonia is adsorbed by the ammonia concentrator, and the ammonia-free tail gas is discharged through the smoke exhaust device 6.

[0105] When the ammonia concentrator is saturated, the desorption device 3 operates, so that the high-concentration ammonia is desorbed and mixed with the tail gas to form desorbed tail gas. The desorbed tail gas passes through the ammonia oxidizer 4, where the ammonia undergoes a catalytic combustion reaction to form nitrogen and water vapor, and then is discharged together with the tail gas through the smoke exhaust device 6.

[0106] Before the tail gas, nitrogen, and water vapor are discharged through the smoke exhaust device 6, the tail gas, nitrogen, and water vapor can be introduced into the ammonia concentrator again, and then discharged through the smoke exhaust device 6 to further eliminate the residual ammonia in the tail gas, nitrogen, and water vapor that did not participate in the oxidation reaction.

[0107] In this embodiment, the adsorption device 2 mainly adsorbs ammonia by activated carbon. The desorption device 3 includes a desorption fan arranged in the tail gas passage and downstream of the adsorption device 2. The desorption fan is used to form a negative pressure inside the adsorption device 2, so that the ammonia adsorbed by the activated carbon is desorbed.

[0108] The prior art also discloses other methods capable of desorbing activated carbon, such as temperature-rising desorption, flushing desorption, displacement desorption, magnetization desorption, and ultrasonic desorption.

[0109] Furthermore:

[0110] In order to prevent the flame inside the ammonia oxidizer 4 from entering the adsorption device 2, a flame arrester 21 is installed between the adsorption device 2 and the ammonia oxidizer 4.

[0111] A cold supplement fan 7 is arranged at a position downstream of the tail gas passage close to the ammonia oxidizer 4. The cold supplement fan 7 is used to suck air from the atmosphere and input it into the tail gas passage. The low-temperature air is mixed into the high-temperature desorbed tail gas, so that the temperature of the desorbed tail gas drops to meet the emission requirements.

[0112] Furthermore:

[0113] The adsorption device 2 includes a first adsorption box 22 and a second adsorption box 23. The first adsorption box 22 is internally provided with a first adsorption bed 221, and the second adsorption box 23 is internally provided with a second adsorption bed 231;

[0114] The filter box 1, the first adsorption box 22, the second adsorption box 23, the desorption device 3, and the smoke exhaust device 6 are connected by an air guiding device 5 to form first, second, and third ammonia removal passages;

[0115] Among them:

[0116] The first ammonia removal path includes a filtering box 1, a first adsorption box 22, and an exhaust device 6 connected in sequence;

[0117] The second ammonia removal path includes a filtering box 1, a second adsorption box 23, a first adsorption box 22, an ammonia oxidizer 4, and an exhaust device 6 connected in sequence;

[0118] The third ammonia removal path includes a filtering box 1, a first adsorption box 22, a second adsorption box 23, an ammonia oxidizer 4, and an exhaust device 6 connected in sequence.

[0119] Both the first adsorption bed 221 and the second adsorption bed 231 are activated carbon adsorption beds, and the filtering box 1 is a dry filtering box.

[0120] The first ammonia removal path operates during initial operation, and its working steps are as follows:

[0121] The ammonia-containing waste gas passes through the filtering box 1 to remove some dust particles and then enters the first adsorption box 22. The first adsorption bed 221 adsorbs and desorbs the ammonia in the waste gas, and the purified clean gas is discharged into the atmosphere by the induced draft fan 51.

[0122] The second ammonia removal path starts to operate after the first adsorption bed 221 in the first adsorption box 22 is saturated with adsorption, and its working steps are as follows:

[0123] The ammonia-containing waste gas passes through the filtering box 1 to remove some dust particles and then enters the second adsorption box 23. The gas after the second adsorption bed 231 adsorbs and desorbs the ammonia in the waste gas enters the first adsorption box 22. The gas after the first adsorption bed 221 adsorbs and desorbs the ammonia in the gas passes through the flame arrester 21 and enters the ammonia oxidizer 4, and nitrogen and water vapor are generated in the ammonia oxidizer 4. The nitrogen passes through the desorption device 3 and the supplementary cooling fan 7 and is then discharged through the exhaust device 6.

[0124] The third ammonia removal path starts to operate after the second adsorption bed 231 in the second adsorption box 23 is saturated with adsorption, and its working steps are as follows:

[0125] The ammonia-containing waste gas passes through the filtering box 1 to remove some dust particles and then enters the first adsorption box 22. The gas after the first adsorption bed 221 adsorbs and desorbs the ammonia in the waste gas enters the second adsorption box 23. The gas after the second adsorption bed 231 adsorbs and desorbs the ammonia in the gas passes through the flame arrester 21 and enters the ammonia oxidizer 4, and nitrogen and water vapor are generated in the ammonia oxidizer 4. The nitrogen passes through the desorption device 3 and the supplementary cooling fan 7 and is then discharged through the exhaust device 6.

[0126] Second and third ammonia removal paths respectively desorb the ammonia adsorbed in the second adsorption bed 231 and the first adsorption bed 221 and mix it into the desorption tail gas. Finally, a catalytic combustion reaction occurs in the ammonia oxidizer 4 to generate nitrogen and water vapor. And during the process that nitrogen passes through the desorption device 3 and the supplementary cooling fan 7 and is discharged through the smoke exhaust device 6, nitrogen can be directly discharged through the smoke exhaust device 6, or can be discharged through the smoke exhaust device 6 after entering the first adsorption box 22.

[0127] It should also be noted that:

[0128] After the temperature of the desorption tail gas is raised and maintained at the target temperature and the ammonia concentration of the desorption tail gas entering the ammonia oxidizer 4 is high enough, the oxidation reaction can be maintained in the self-sustaining catalytic combustion stage. Then, the heating of the ammonia oxidizer 4 is changed to an intermittent mode, and the cycle of the intermittent mode is 0.5 hour to 1 hour. At this time, it enters the stable operation state.

[0129] Furthermore:

[0130] The air induction device 5 includes an induced draft fan 51 and a three-way valve 52 arranged in the tail gas passage and downstream of the ammonia oxidizer 4;

[0131] A first stop valve 222 is provided on the first adsorption box 22 close to the filtration box 1 side, a second stop valve 223 is provided on the first adsorption box 22 close to the smoke exhaust device 6 side, a third stop valve 224 is provided on the first adsorption box 22 close to the second adsorption box 23 side, and a fourth stop valve 225 is provided on the first adsorption box 22 far from the second adsorption box 23 side;

[0132] A fifth stop valve 232 is provided on the second adsorption box 23 close to the filtration box 1 side, a sixth stop valve 233 is provided on the second adsorption box 23 close to the smoke exhaust device 6 side, a seventh stop valve 234 is provided on the second adsorption box 23 close to the first adsorption box 22 side, and an eighth stop valve 235 is provided on the second adsorption box 23 far from the first adsorption box 22 side;

[0133] Among them, the first stop valve 222 and the fifth stop valve 232 are connected to the filtration box 1, the second stop valve 223 and the sixth stop valve 233 are connected to the smoke exhaust device 6, the third stop valve 224 and the eighth stop valve 235 are connected to the ammonia oxidizer 4, the fourth stop valve 225 and the seventh stop valve 234 are connected to the desorption device 3 through the three-way valve 52, and the remaining end of the three-way valve 52 is connected to the smoke exhaust device 6 through the induced draft fan 51.

[0134] The method for opening the first ammonia removal path is:

[0135] Open the first stop valve 222 and the second stop valve 223, and close the third stop valve 224, the fourth stop valve 225, the fifth stop valve 232, the sixth stop valve 233, the seventh stop valve 234, and the eighth stop valve 235.

[0136] The method for opening the second ammonia removal passage is as follows:

[0137] Open the fifth stop valve 232, the sixth stop valve 233, the third stop valve 224, and the fourth stop valve 225, and close the first stop valve 222, the second stop valve 223, the seventh stop valve 234, and the eighth stop valve 235.

[0138] The method for opening the third ammonia removal passage is as follows:

[0139] Open the first stop valve 222, the second stop valve 223, the seventh stop valve 234, and the eighth stop valve 235, and close the third stop valve 224, the fourth stop valve 225, the fifth stop valve 232, and the sixth stop valve 233.

[0140] It should also be noted that:

[0141] The induced draft fan 51 draws out the ammonia-removed gas and discharges it through the smoke exhaust device 6.

[0142] The smoke exhaust device 6 is a chimney or other devices in the prior art that can achieve smoke exhaust.

[0143] The three-way valve 52 is used to discharge a part of the burned gas to the atmosphere through the smoke exhaust device 6. The three-way valve 52 can control the volume of the discharged gas according to the total amount of the circulating gas, control the total amount of the circulating gas within the target range, prevent excessive air pressure in the pipeline, and avoid the problem that the desorbed ammonia cannot reach the self-sustaining catalytic combustion concentration.

[0144] The ammonia removal system is electrically connected to a controller 800, and the staff operates the controller 800 to realize the operation of the ammonia removal equipment.

[0145] The above embodiments are only exemplary embodiments of the present invention and are not used to limit the present invention. The protection scope of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements within the essence and protection scope of the present invention, and such modifications or equivalent replacements should also be regarded as falling within the protection scope of the embodiments of the present invention.

Claims

1. An ammonia oxidizer for a tail gas ammonia removal system, characterized in that, Reaction chamber (41); Catalyst (42), disposed in the middle of the reaction chamber (41) and partitioning the interior of the reaction chamber (41) into a first chamber and a second chamber, the catalyst (42) being a grid structure; Intake pipe (411), communicating with the interior of the reaction chamber (41) and configured to introduce tail gas containing high-concentration ammonia into the reaction chamber (41); Heater (43), disposed inside the reaction chamber (41) and configured to raise the temperature inside the reaction chamber (41) such that the interior of the reaction chamber (41) has an initial temperature for catalytic combustion reaction of ammonia; Outlet pipe (412), communicating with the interior of the reaction chamber (41) and configured to discharge ammonia after catalytic combustion reaction; Flow deflector, disposed inside the reaction chamber (41) and configured to guide the airflow inside the reaction chamber (41) to circulate reciprocally between the first chamber and the second chamber; Valve group, configured to alternately open and close the intake pipe (411) and the outlet pipe (412) such that the outlet pipe (412) is closed when the intake pipe (411) is open, and the intake pipe (411) is closed when the outlet pipe (412) is open; The flow deflector includes a Venturi tube (46), the Venturi tube (46) being disposed inside the first chamber and coaxially connected to the intake pipe (411), the outlet end of the Venturi tube (46) facing the catalyst (42), and a through hole (461) being provided at the throat of the Venturi tube (46); When the intake pipe (411) is open, the gas inside the first chamber is sucked into the Venturi tube (46) through the through hole (461) and flows through the catalyst (42) to the second chamber, and then flows through the catalyst (42) again along the inner wall of the reaction chamber (41) to the first chamber; A temperature sensor is provided on the catalyst (42), the temperature sensor being configured to detect the temperature of the catalyst (42). When the temperature of the catalyst (42) drops to near the temperature for catalytic combustion reaction of ammonia, the valve group opens the intake pipe (411) and closes the outlet pipe (412); A pressure sensor is disposed inside the reaction chamber (41), the pressure sensor being configured to detect the air pressure inside the reaction chamber (41). The valve group opens the outlet pipe (412) and closes the intake pipe (411) when the air pressure inside the reaction chamber (41) rises to a threshold value.

2. The ammonia oxidizer for a tail gas ammonia removal system according to claim 1, characterized in that, The flow deflector includes a vortex blower (44), the fan blades of the vortex blower (44) being disposed inside the second chamber and facing the intake pipe (411). The vortex blower (44) is configured to axially suck in gas and radially discharge gas such that the gas inside the first chamber enters the second chamber through the catalyst (42) along the center of the reaction chamber (41), and then flows along the wall surface of the reaction chamber (41) and enters the first chamber through the catalyst (42) again.

3. The ammonia oxidizer for a tail gas ammonia removal system according to claim 1, characterized in that, The said air outlet pipe (412) is sleeved outside the said air inlet pipe (411).

4. The ammonia oxidizer for a tail gas ammonia removal system according to claim 1 or 3, characterized in that, The said valve group includes a ninth stop valve (45), a tenth stop valve (47) and a driver (49). The ninth stop valve (45) includes a first valve core capable of blocking the air outlet pipe (412), and the tenth stop valve (47) includes a second valve core capable of blocking the air inlet pipe (411). The first valve core and the second valve core are fixedly connected to the actuator of the driver (49) through a connecting member (48).

5. The ammonia oxidizer for a tail gas ammonia removal system according to claim 4, characterized in that, The said driver (49) is arranged inside the said air inlet pipe (411).

6. The ammonia oxidizer for a tail gas ammonia removal system according to claim 5, characterized in that, The said air outlet pipe (412) is separated from the said air inlet pipe (411) at a position close to the said driver (49).

7. An ammonia oxidation method for a tail gas ammonia removal system, characterized in that, The said ammonia oxidation method is applied to the ammonia oxidizer according to any one of claims 1-6. The said ammonia oxidation method includes the following steps: S1. Obtain a reaction chamber having an air inlet pipe and an air outlet pipe. Install a flow guide device inside the reaction chamber capable of enabling the gas to circulate repeatedly inside the reaction chamber, and arrange the catalyst for the catalytic combustion reaction in the necessary path for the gas to circulate repeatedly. S2. Raise the temperature inside the reaction chamber so that the inside of the reaction chamber has an initial temperature for the catalytic combustion reaction of ammonia. S3a. When the temperature inside the reaction chamber drops to close to the initial temperature of the catalytic combustion reaction, open the air inlet pipe and close the air outlet pipe, and introduce the tail gas containing high-concentration ammonia into the reaction chamber through the air inlet pipe. The ammonia circulates repeatedly inside the reaction chamber to repeatedly pass through the catalyst for the catalytic combustion reaction. S3b. When the air pressure inside the reaction chamber rises to the threshold value, close the air inlet pipe and open the air outlet pipe, and the ammonia that has fully undergone the catalytic combustion reaction leaves the reaction chamber through the air outlet pipe.

Images