Flue gas purification device for removing ammonia escape from denitration tail gas

Abstract

The invention belongs to the technical field of multi-pollutant cooperative control, and discloses a flue gas purification device for removing denitration tail gas ammonia escape, the flue gas purification device comprises a dry process tower, a catalysis chamber, an ash bin and an ammonia area, composite filter pipes are distributed in the catalysis chamber in an array mode, and each composite filter pipe comprises a ceramic inner pipe and a ceramic outer pipe which are coaxially arranged; the ceramic outer pipe is coated with a breathable filter layer sleeve, the aperture of the ceramic inner pipe is smaller than that of the ceramic outer pipe, and a first catalyst layer is arranged on the inner wall of the ceramic inner pipe; an assembling shaft assembly is installed in the ceramic inner pipe in a sliding mode and comprises a center shaft and a second catalyst layer arranged on the outer wall of the center shaft in a sleeving mode. The annular double-layer reaction zone is formed by the ceramic inner wall catalyst layer I and the central shaft catalyst layer II, so that a longer contact path and a larger active surface area are obtained when flue gas passes through the composite filter tube, the NH3 slip treatment capacity is improved, the synergistic reaction of double catalytic zones is realized, and the NH3 conversion efficiency is improved.

Description

Flue gas purification device for removing ammonia escape from denitrification tail gas Technical Field

[0001] This invention belongs to the field of multi-pollutant synergistic control technology, specifically a flue gas purification device for removing ammonia escape from denitrification tail gas. Background Technology

[0002] Coal-fired boilers, industrial furnaces, and large combustion equipment commonly employ selective catalytic reduction (SCR) technology to remove NO. X Removal. SCR systems require the injection of NH3 water or urea solution as a reducing agent, but in actual operation, NH3 slip often occurs, meaning unreacted NH3 remains in the exhaust gas. The hazards of this include:

[0003] It combines with SO3 to form ammonium sulfate, causing blockage and corrosion in heat exchangers;

[0004] Cause PM 2.5 The increase in secondary particles caused environmental indicators to exceed standards;

[0005] This affects the long-term stability of subsequent dust collector filter bags or ceramic filter tubes.

[0006] To further reduce NH3 slip, existing technologies often employ wet ammonia removal, combined with honeycomb catalysts and ceramic filter tube denitrification structures, but the following technical bottlenecks still exist:

[0007] (1) The single-stage catalytic structure is difficult to achieve the NH3 conversion efficiency at high space velocity. Conventional single-layer VW / TiO2 catalysts have insufficient reaction residence time at high flue gas flow rates, which easily leads to NH3 breakthrough.

[0008] (2) The ceramic filter tube backflushing relies on a fixed throttling structure, resulting in limited regeneration capacity. Filter dust or sulfates are easy to accumulate on the ceramic wall. Traditional backflushing structures cannot form periodic pulsating airflow, resulting in limited dust removal effect. Summary of the Invention

[0009] The purpose of this invention is to provide a flue gas purification device for removing ammonia escape from denitrification tail gas, so as to solve the problems mentioned in the background art.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a flue gas purification device for removing ammonia escape from denitrification tail gas, comprising a dry tower, a catalytic chamber, an ash bin, and an ammonia zone. The catalytic chamber contains an array of composite filter tubes, each comprising a coaxially arranged ceramic inner tube and a ceramic outer tube. The ceramic outer tube is covered with an air-permeable filter layer sleeve. The pore size of the ceramic inner tube is smaller than that of the ceramic outer tube. A catalyst layer is provided on the inner wall of the ceramic inner tube.

[0011] An assembly shaft assembly is slidably installed inside the ceramic inner tube. The assembly shaft assembly includes a central shaft and a second catalyst layer sleeved on the outer wall of the central shaft. The second catalyst layer and the first catalyst layer form an annular reaction chamber.

[0012] The composite filter tube is provided with an outlet cover with an air outlet at the top. An adjustment mechanism is connected to the upper end of the central shaft. The adjustment mechanism includes a gradient sealing plug. When the central shaft moves back and forth, the gradient sealing plug cooperates with the air outlet to realize the periodic change of the volume of the annular reaction chamber and change the effective cross section of the air outlet channel, so as to make the airflow pulsate.

[0013] The central shaft has a through central channel and side holes that connect to the central channel.

[0014] The catalytic chamber is equipped with a ventilation gripping mechanism, which is used to drive the central shaft to rise and fall, and to supply gas to the central channel when the central shaft moves down to a predetermined position. The gas is introduced into the annular reaction chamber through the side hole to complete the backflushing and dust removal.

[0015] Preferably, the assembly shaft assembly further includes a positioning ring fixed to the inner wall of the ceramic inner tube and a fixing ring fixedly sleeved on the outside of the central shaft. A spring is provided between the fixing ring and the positioning ring, and the central shaft slides through the positioning ring.

[0016] Preferably, the gradient sealing plug has a conical structure, and its insertion depth into the air outlet varies with the stroke of the central shaft.

[0017] Preferably, the gradient sealing plug has a stepped structure, including an upper plug and a lower plug. The bottom of the lower plug is fixedly connected to a connecting crank rod, which is fixedly connected to a central shaft. The outer diameter of the lower plug is smaller than that of the upper plug.

[0018] Preferably, the first catalyst layer is a VW / TiO2-based denitrification catalyst layer, and the second catalyst layer is a Ce-Mn-O x The oxidation catalytic layer, the filter sleeve is a replaceable porous fiber membrane layer, and both ends of the ceramic inner tube and the ceramic outer tube are fixed with assembly rings.

[0019] Preferably, a partition is fixedly connected inside the catalytic chamber, and the arrayed composite filter tubes are installed on the partition, which divides the catalytic chamber into a dust-containing chamber and a clean air chamber.

[0020] Preferably, a connecting pipeline is provided between the catalytic chamber and the dry process tower, a discharge pipeline is provided at the top of the catalytic chamber, and the bottom outlet of the catalytic chamber is connected to the ash silo.

[0021] Preferably, the ventilated gripping mechanism includes a support plate, a connecting frame, an electric push rod, a gripping plate, an air pump, and a matching hole. The electric push rod is used to drive the gripping plate to lift and lower, thereby controlling the movement of the central shaft. The air pump's outlet end supplies air to the connecting frame, and its intake end passes through the catalytic chamber. The connecting frame is connected to the central channel. An assembly mechanism is detachably mounted on the top of the gripping plate.

[0022] Preferably, a connecting mechanism is installed at the bottom of the central shaft. The connecting mechanism is detachably connected to the assembly mechanism. The connecting mechanism includes a threaded conduit, an inner annular groove, and a "T"-shaped assembly tube. The threaded conduit is threadedly fitted onto the bottom of the central shaft and communicates with the central channel. The inner annular groove is formed on the inner wall of the threaded conduit. The "T"-shaped assembly tube is movably fitted onto the bottom of the threaded conduit, and the upper end of the "T"-shaped assembly tube is adapted to fit into the inner annular groove.

[0023] Preferably, the assembly mechanism includes an assembly head, an internal cavity, and a one-way valve. The assembly head is detachably mounted on the gripping plate. The internal cavity is opened in the assembly head. The one-way valve is installed at the bottom of the assembly head and is used to open when the ventilated gripping mechanism supplies air. The top of the assembly head is threaded with a "T"-shaped assembly pipe. The assembly head mates with a suitable matching hole.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. This invention forms an annular double-layer reaction zone by using a ceramic inner wall catalyst layer one and a central axis catalyst layer two, which allows the flue gas to obtain a longer contact path and a larger active surface area when passing through the composite filter tube, thereby improving the NH3slip treatment capacity, realizing the synergistic reaction of the two catalytic zones, and improving the NH3 conversion efficiency.

[0026] 2. This invention forms a radial gradient filter by the difference in pore size between the inner and outer ceramic tubes. The outer filter layer traps fine particles and protects the inner catalyst layer from dust erosion, thus combining filtration and catalytic protection.

[0027] 3. This invention achieves airflow pulsation through gradual sealing plug adjustment, enhancing catalytic activity and regeneration capability. Variable volume and variable cross-section cause periodic velocity and pressure fluctuations in the flue gas, promoting enhanced mass transfer on the catalyst surface and inhibiting deposition.

[0028] 4. This invention has a built-in back-flushing regeneration structure, which has a significant online dust removal effect. The central shaft inner hole and side holes spray outward under the action of air supply, forming a "from the inside to the outside" back-flushing flow, which removes the dust accumulation on the ceramic wall surface and filter layer surface and enhances long-term stability.

[0029] 5. This invention reduces footprint and resistance through a highly integrated structure, and realizes catalysis and filtration functions in the same composite filter tube, avoiding the problems of large size, high resistance and complex maintenance caused by traditional SCR + ceramic filter tube series connection. Attached Figure Description

[0030] Figure 1 is a schematic diagram of the structure of the present invention;

[0031] Figure 2 is a schematic diagram showing the connection between the catalytic chamber of the present invention and the connecting pipeline and the discharge pipeline, respectively;

[0032] Figure 3 is a cross-sectional schematic diagram of the catalytic chamber of the present invention;

[0033] Figure 4 is a schematic diagram of the assembly of the composite filter tube, baffle and air gripping mechanism of the present invention.

[0034] Figure 5 is a schematic diagram of the composite filter tube of the present invention;

[0035] Figure 6 is a cross-sectional view of the composite filter tube and the assembly shaft of the present invention;

[0036] Figure 7 is an enlarged schematic diagram of the structure at point A in Figure 6;

[0037] Figure 8 is an enlarged schematic diagram of the structure at point B in Figure 6;

[0038] Figure 9 is a partial schematic diagram of the top of the central shaft of the present invention;

[0039] Figure 10 is a cross-sectional view of the composite filter tube of the present invention;

[0040] Figure 11 is a cross-sectional view of the assembly shaft assembly of the present invention;

[0041] Figure 12 is a schematic diagram of the ventilated gripping mechanism of the present invention;

[0042] Figure 13 is a cross-sectional view of the ventilated gripping mechanism of the present invention;

[0043] Figure 14 is a cross-sectional view of the ventilation mechanism and assembly mechanism of the present invention.

[0044] In the diagram: 1. Catalytic chamber; 2. Dry process tower; 3. Ash silo; 4. Ammonia zone; 5. Connecting pipeline; 6. Discharge pipeline; 7. Baffle plate; 8. Composite filter tube; 81. Assembly ring; 82. Ceramic inner tube; 83. Ceramic outer tube; 84. Filter layer sleeve; 85. Catalyst layer one; 9. Ventilation and gripping mechanism; 91. Support plate; 92. Connecting frame; 93. Electric push rod; 94. Gripping plate; 95. Air pump; 96. Adaptive fitting hole; 10. Connecting mechanism; 101. Threaded conduit; 10 2. Inner ring groove; 103. "T" type assembly tube; 11. Assembly mechanism; 111. Assembly head; 112. Internal cavity; 113. One-way valve; 12. Assembly shaft assembly; 121. Central shaft; 122. Catalyst layer two; 123. Fixing ring; 124. Spring; 125. Positioning ring; 126. Central channel; 127. Side hole; 13. Outlet cover; 14. Adjustment mechanism; 141. Upper plug; 142. Lower plug; 143. Connecting crank; 15. Air outlet. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] As shown in Figures 1 to 14, embodiments of the present invention provide a flue gas purification device for removing ammonia escape from denitrification tail gas, including a dry tower 2, a catalytic chamber 1, an ash bin 3, and an ammonia zone 4. The catalytic chamber 1 contains an array of composite filter tubes 8, each comprising a coaxially arranged inner ceramic tube 82 and an outer ceramic tube 83. The outer ceramic tube 83 is covered with a breathable filter sleeve 84. The pore size of the inner ceramic tube 82 is smaller than that of the outer ceramic tube 83. A catalyst layer 85 is provided on the inner wall of the inner ceramic tube 82. An assembly shaft assembly 12 is slidably installed inside the inner ceramic tube 82. The assembly shaft assembly 12 includes a central shaft 121 and a second catalyst layer 122 sleeved on the outer wall of the central shaft 121. An annular reaction chamber is formed between the second catalyst layer 122 and the first catalyst layer 85. The composite filter tube 8 is provided with an outlet cover 13 with an air outlet 15 at the top. The upper end of the central shaft 121 is connected to an adjustment mechanism 14. The adjustment mechanism 14 includes a gradient sealing plug. When the central shaft 121 moves back and forth, the gradient sealing plug cooperates with the air outlet 15 to realize the periodic change of the volume of the annular reaction chamber and change the effective cross section of the air outlet channel, so that the airflow pulsates. The central shaft 121 is provided with a through central channel 126 and a side hole 127 that connects to the central channel 126. The catalytic chamber 1 is provided with a ventilation gripping mechanism 9. The ventilation gripping mechanism 9 is used to drive the central shaft 121 to rise and fall, and to supply air to the central channel 126 when the central shaft 121 moves down to a predetermined position. The gas is introduced into the annular reaction chamber through the side hole 127 to complete the backflushing and cleaning.

[0047] Example 1: During use, it contains dust and NO. x After pretreatment in dry process tower 2, the flue gas containing escaped ammonia enters the dust-laden chamber of catalytic chamber 1. Under external pressure, the flue gas penetrates the filter layer sleeve 84 and ceramic outer tube 83 of composite filter tube 8, and the dust is trapped on the outer surface to form a filter cake. The clean flue gas enters the ceramic inner tube 82 and flows into the annular reaction chamber formed by catalyst layer 1 85 and catalyst layer 2 122. During this process, NO... xThe ammonia is reduced on catalyst layer 85 and oxidized on catalyst layer 122. During normal operation, the electric push rod 93 of the ventilation gripping mechanism 9 drives the gripping plate 94 (which in turn drives the central shaft 121) to perform small-amplitude, periodic reciprocating up and down. When the central shaft 121 moves up or down, the insertion depth of the adjustment mechanism 14 (gradual sealing plug) at its top changes at the outlet 15, causing the effective cross-section of the outlet to change periodically (throttling). This throttling effect causes the pressure and flue gas velocity in the annular reaction chamber to fluctuate periodically, i.e., "airflow pulsation". The pulsation breaks the fluid boundary layer and greatly enhances the mass transfer between the flue gas and the catalyst surface, thereby significantly improving the reaction efficiency of denitrification and deammoniation. The purified gas is finally discharged into the clean gas chamber through the outlet 15, and then discharged into the chimney through the discharge pipe 6 and the exhaust fan.

[0048] The assembly shaft assembly 12 also includes a positioning ring 125 fixed to the inner wall of the ceramic inner tube 82 and a fixing ring 123 fixedly sleeved on the outside of the central shaft 121. A spring 124 is provided between the fixing ring 123 and the positioning ring 125, and the central shaft 121 slides through the positioning ring 125.

[0049] The positioning ring 125 is fixedly installed on the inner wall of the ceramic inner tube 82 to limit the axial position of the assembly shaft assembly 12 and provide a guiding reference for the central shaft 121. The fixing ring 123 is sleeved on the outside of the central shaft 121 and moves synchronously with the central shaft 121. Its outer diameter matches the inner diameter of the positioning ring 125 to maintain axial stability during the lifting and lowering of the central shaft 121. The spring 124 is set between the positioning ring 125 and the fixing ring 123 to apply a restoring force to the central shaft 121 after compression and to enable the central shaft 121 to maintain its initial position when not driven by external force. The central shaft 121 slides through the positioning ring 125 to achieve axial guidance, prevent eccentric friction, and ensure the smoothness and reliability of the assembly shaft assembly 12 during the reciprocating stroke. A sealing gasket can be set in the mating area between the positioning ring 125 and the central shaft 121 to achieve dynamic sealing sliding.

[0050] The tapered sealing plug has a conical structure, and its insertion depth into the air outlet 15 varies with the stroke of the central shaft 121.

[0051] The tapered, tapered sealing plug achieves a gradual adjustment of the effective throttling area corresponding to the change in insertion depth through its gradually increasing cone diameter. As the central shaft 121 moves downward along the inner ceramic tube 82, the tapered sealing plug gradually penetrates deeper into the outlet 15. Its tapered outer wall and the inner wall of the outlet form different degrees of obstruction, thereby continuously changing the flow cross-sectional area of ​​the outlet 15. This structure can achieve continuous and controllable adjustment of the instantaneous exhaust velocity, pressure, and flow rate of the annular reaction chamber, causing the flue gas to form periodic pressure fluctuations in the filter tube. These pressure fluctuations are used to enhance the mass transfer rate of the surfaces of catalyst layer 1 85 and catalyst layer 2 122, and to strengthen the airflow disturbance caused by the cross-sectional change, thereby improving the efficiency of the NH3 oxidation reaction.

[0052] The gradient sealing plug has a stepped structure, including an upper plug 141 and a lower plug 142. The bottom of the lower plug 142 is fixedly connected to a connecting crank 143, which is fixedly connected to the central shaft 121. The outer diameter of the lower plug 142 is smaller than that of the upper plug 141.

[0053] The stepped, gradually changing sealing plug consists of an upper plug 141 and a lower plug 142 with different outer diameters. The step change between the upper and lower plugs creates a sudden throttling state during insertion into the air outlet 15. When the central shaft 121 moves downward, the lower plug 142 is inserted into the air outlet 15 first, throttling the airflow channel. As it continues to move downward, the upper plug 141 is further inserted, sealing the flow section and achieving a sealing treatment. Therefore, this stepped structure can provide different treatments under different working conditions: the lower plug 142 provides throttling treatment, and the upper plug 141 provides sealing treatment.

[0054] Among them, catalyst layer 85 is a VW / TiO2-based denitration catalyst layer, and catalyst layer 122 is a Ce-Mn-O x The oxidation catalyst layer and the filter sleeve 84 are replaceable porous fiber membrane layers. Both ends of the ceramic inner tube 82 and the ceramic outer tube 83 are fixed with assembly rings 81.

[0055] Catalyst layer 185 uses a VW / TiO2 formulation, which can achieve efficient NH3–NO under medium temperature conditions. X The reduction reaction, with catalyst layer 122 being Ce-Mn-O. x The oxidizing catalyst layer is mainly used to oxidize NH3 and some difficult-to-convert reducing gases. The two catalyst layers are set along the flue gas flow, so that the flue gas undergoes a two-stage treatment of reduction and oxidation in the annular reaction chamber, thereby greatly improving the treatment efficiency of NH3slip. The filter sleeve 84, as the outermost filter structure, is made of a replaceable porous fiber membrane material. It can capture fine particulate matter and remove ash in time under the action of backflush airflow. Its replaceable feature facilitates maintenance and long-term operation. The three structures work together to enable the purification device to have the triple effects of filtration, oxidation and denitrification.

[0056] The assembly ring 81 is specifically used to support and connect the ceramic inner tube 82 and the ceramic outer tube 83. The top assembly ring 81 is also used to thread it onto the partition 7. The top of the top assembly ring 81 is provided with an adapter mounting cavity for threaded installation of the outlet cover 13.

[0057] The catalyst chamber 1 is fixedly connected to a partition 7, and the arrayed composite filter tubes 8 are installed on the partition 7. The partition 7 divides the catalyst chamber 1 into a dust-containing chamber and a clean air chamber.

[0058] The partition 7 divides the catalytic chamber 1 into an upper clean gas chamber and a lower dust-containing chamber, and serves as the mounting base for the composite filter tube 8. The flue gas is drawn into the dust-containing chamber by the composite filter tube 8 one by one, filtered by the filter layer sleeve 84 and the ceramic tube wall, and then enters the annular reaction chamber for catalysis. Finally, it is discharged into the clean gas chamber from the gas outlet 15 at the top of the composite filter tube. The structure of the partition 7 ensures that the gas can only enter the clean gas chamber through the filter tube, effectively avoiding bypass leakage. Through array installation, the composite filter tubes 8 can be evenly distributed to form a regular airflow field.

[0059] The catalyst chamber 1 is connected to the dry tower 2 by a connecting pipe 5, the top of the catalyst chamber 1 is connected to a discharge pipe 6, and the bottom outlet of the catalyst chamber 1 is connected to the ash silo 3. In the dry tower 2, the desulfurizing agent forms a turbulent zone in the tower, which prolongs the contact between the desulfurizing agent and the dust and improves the chemical absorption efficiency.

[0060] The number of catalytic chambers 1 is preferably 8 or 10, which can be operated independently. The treated gas is discharged through the discharge pipe 6 in conjunction with an external fan. The ash bin 3 collects the waste ash from the catalytic chamber 1. The ammonia zone 4 is arranged independently and is used to store and quantitatively inject ammonia gas or ammonia solution for use in the denitrification reaction.

[0061] Connecting pipe 5 connects dry tower 2 and catalytic chamber 1, so that the flue gas after dry treatment can be stably delivered to the catalytic chamber 1 for deep ammonia removal and filtration; discharge pipe 6 is used for the exhaust of purified air.

[0062] The ventilation gripping mechanism 9 includes a support plate 91, a connecting frame 92, an electric push rod 93, a gripping plate 94, an air pump 95, and a matching hole 96. The electric push rod 93 is used to drive the gripping plate 94 to lift and lower, so as to control the movement of the central shaft 121. The air pump 95 supplies air to the connecting frame 92 at the outlet end and the air intake end passes through the catalytic chamber 1. The connecting frame 92 is connected to the central channel 126. The top of the gripping plate 94 is detachably equipped with an assembly mechanism 11.

[0063] The support plate 91 is fixedly installed on the inner wall of the catalytic chamber 1 to support the components of the ventilation gripping mechanism 9. The electric push rod 93 is fixed on the support plate 91 and directly drives the gripping plate 94 to rise and fall through its telescopic movement, so that the gripping plate 94 drives the central shaft 121 to move up or down as a whole, thereby realizing real-time adjustment of the insertion depth of the gradient sealing plug. The suction end of the air pump 95 passes through the catalytic chamber 1 to draw in clean gas from the outside, while the exhaust end supplies gas to the connecting frame 92. The connecting frame 92 is connected with the central channel 126. Under the action of the air pump 95, the airflow is introduced into the central channel 126 through the assembly mechanism 11 to form internal backflushing. The matching hole 96 is used to accommodate the lower end of the assembly mechanism 11. The assembly mechanism 11 itself is detachably installed on the gripping plate 94 for easy disassembly and assembly. This mechanism integrates the functions of mechanical lifting and airflow conveying, and is the core component for realizing variable volume adjustment and backflushing cleaning.

[0064] The bottom of the central shaft 121 is connected to a connecting mechanism 10, which is detachably connected to the assembly mechanism 11. The connecting mechanism 10 includes a threaded conduit 101, an inner annular groove 102, and a "T"-shaped assembly tube 103. The threaded conduit 101 is threaded onto the bottom of the central shaft 121 and communicates with the central channel 126. The inner annular groove 102 is formed on the inner wall of the threaded conduit 101. The "T"-shaped assembly tube 103 is movably fitted onto the bottom of the threaded conduit 101. The upper end of the tube 103 is adapted to be connected in the inner ring groove 102. The assembly mechanism 11 includes an assembly head 111, an internal cavity 112 and a one-way valve 113. The assembly head 111 is detachably mounted on the gripping plate 94. The internal cavity 112 is opened in the assembly head 111. The one-way valve 113 is installed at the bottom of the assembly head 111 and is used to open when the ventilating gripping mechanism 9 supplies air. The top of the assembly head 111 is threadedly connected to the "T"-shaped assembly tube 103. The assembly head 111 is matched with the adapted matching hole 96.

[0065] The connecting mechanism 10 is installed at the bottom of the central shaft 121 and is detachably connected to the central shaft 121 via the threaded conduit 101, while maintaining gas communication with the central channel 126. An inner annular groove 102 is provided on the inner wall of the threaded conduit 101 to provide positioning and limiting functions for the "T"-shaped assembly tube 103. The "T"-shaped assembly tube 103 is movably sleeved on the lower end of the threaded conduit 101, with its upper end inserted into the inner annular groove 102. This allows the "T"-shaped assembly tube 103 to slide slightly while maintaining airtightness, adapting to the position of the assembly mechanism 11 on the gripping plate 94, reserving installation space, and facilitating the alignment and installation of the assembly mechanism 11. This structure ensures that the backflush airflow can travel from the air pump 95 through the assembly mechanism. 11. The connecting frame 92 enters the central channel 126 and is then ejected from the side hole 127, achieving a stable and reliable backflushing operation. The internal cavity 112 is located inside the assembly head 111 and serves as a flow channel transition cavity for the air pump 95 to deliver gas to the central channel 126. The one-way valve 113 is installed at the bottom of the assembly head 111, with its opening direction pointing towards the threaded guide tube 101, so that the backflushing gas can only enter the central channel 126, preventing flue gas or dust from flowing back into the ventilation gripping mechanism 9. The top of the assembly head 111 is threadedly connected to the "T"-shaped assembly tube 103, achieving reliable sealing and detachable installation. The above structure gives the assembly mechanism 11 good sealing performance, maintainability, and airflow control capabilities, and is an important part of the backflushing cleaning process.

[0066] Example 2: As the operating time increases, the dust layer (filter cake) on the outer surface of the filter layer sleeve 84 gradually thickens, causing the system resistance (pressure drop) to increase. When the pressure drop reaches the set threshold, the system starts the backflushing cleaning program. At this time, the electric push rod 93 of the ventilation gripping mechanism 9 drives the gripping plate 94 to descend to the predetermined position (extreme position). At this position, the assembly head 111 of the assembly mechanism 11 and the matching hole 96 on the connecting frame 92 achieve a sealing connection. Subsequently, the air pump 95 starts and pumps high-pressure gas into the connecting frame 92. The gas opens the one-way valve 113 at the bottom of the assembly mechanism 11 and enters the internal cavity 112 and the connecting mechanism 112 in sequence. 0, and finally introduced into the central channel 126 of the central shaft 121. High-pressure gas is injected into the annular reaction chamber at high speed through the side hole 127 from the central channel 126. Since the central shaft 121 is in the predetermined downward position at this time, the adjustment mechanism 14 (gradual sealing plug) at its top has completely sealed the outlet 15. The high-pressure gas can only penetrate the ceramic inner tube 82, ceramic outer tube 83 and filter sleeve 84 from the inside to the outside in the reverse direction. The back-blowing airflow will blow away and peel off the dust filter cake attached to the outer surface of the filter sleeve 84. The dust falls into the bottom of the catalytic chamber 1 under the action of gravity. After the dust removal is completed, the air pump 95 stops and the electric push rod 93 returns to the normal operating pulse mode.

[0067] Working principle and usage process of this invention:

[0068] Filtration and Pulsed Catalysis:

[0069] Contains dust, NO x After the flue gas containing ammonia is pretreated by the dry tower 2, it enters the dust-laden chamber of the catalytic chamber 1. Under the action of external pressure, the flue gas penetrates the filter layer sleeve 84 and the ceramic outer tube 83 of the composite filter tube 8, and the dust is trapped on the outer surface to form a filter cake.

[0070] Clean flue gas enters the ceramic inner tube 82 and flows into the annular reaction chamber formed by catalyst layer one 85 and catalyst layer two 122. During this process, NO... x The ammonia is reduced on catalyst layer 85, and the escaped ammonia is oxidized on catalyst layer 122.

[0071] During normal operation, the electric push rod 93 of the ventilation gripping mechanism 9 drives the gripping plate 94 (which in turn drives the central shaft 121) to perform small-amplitude, periodic reciprocating up and down. When the central shaft 121 moves up or down, the insertion depth of the adjustment mechanism 14 (gradual sealing plug) at its top changes at the outlet 15, causing the effective cross-section of the outlet to change periodically (throttling). This throttling effect causes the pressure and flue gas velocity in the annular reaction chamber to fluctuate periodically, i.e., "airflow pulsation". The pulsation breaks the fluid boundary layer and greatly enhances the mass transfer between the flue gas and the catalyst surface, thereby significantly improving the reaction efficiency of denitrification and deammoniation. The purified gas is finally discharged into the clean gas chamber through the outlet 15, and then discharged through the discharge pipe 6 and discharged into the chimney after cooperating with the exhaust fan.

[0072] Backflushing for dust removal:

[0073] As the operating time increases, the dust layer (filter cake) on the outer surface of the filter jacket 84 gradually thickens, causing the system resistance (pressure drop) to increase. When the pressure drop reaches the set threshold, the system starts the backflushing cleaning program.

[0074] At this time, the electric push rod 93 of the ventilation gripping mechanism 9 drives the gripping plate 94 to descend to the predetermined position (extreme position). In this position, the assembly head 111 of the assembly mechanism 11 and the matching hole 96 on the connecting frame 92 achieve a mating seal.

[0075] Subsequently, the air pump 95 starts, pumping high-pressure gas into the connecting frame 92. The gas opens the one-way valve 113 at the bottom of the assembly mechanism 11, enters the internal cavity 112 and the connecting mechanism 10 in sequence, and finally enters the central channel 126 of the central shaft 121. The high-pressure gas is injected at high speed into the annular reaction chamber through the side hole 127 from the central channel 126. Since the central shaft 121 is in the predetermined downward position at this time, the adjustment mechanism 14 (gradient sealing plug) at its top has completely closed the outlet 15. The high-pressure gas can only penetrate the ceramic inner tube 82, ceramic outer tube 83 and filter sleeve 84 from the inside to the outside in the reverse direction. The back-blowing airflow blows away and peels off the dust filter cake attached to the outer surface of the filter sleeve 84. The dust falls into the bottom of the catalytic chamber 1 under the action of gravity. After the dust removal is completed, the air pump 95 stops, and the electric push rod 93 returns to the normal operating pulse mode.

Claims

1. A flue gas purification device for removing ammonia escape from denitrification tail gas, comprising a dry process tower (2), a catalytic chamber (1), an ash bin (3), and an ammonia zone (4), wherein composite filter tubes (8) are arranged in an array within the catalytic chamber (1), characterized in that: The composite filter tube (8) includes a coaxially arranged ceramic inner tube (82) and ceramic outer tube (83). The ceramic outer tube (83) is covered with an air-permeable filter sleeve (84). The pore size of the ceramic inner tube (82) is smaller than that of the ceramic outer tube (83). The inner wall of the ceramic inner tube (82) is provided with a catalyst layer (85). An assembly shaft assembly (12) is slidably installed inside the ceramic inner tube (82). The assembly shaft assembly (12) includes a central shaft (121) and a catalyst layer (122) sleeved on the outer wall of the central shaft (121). An annular reaction chamber is formed between the catalyst layer (122) and the catalyst layer (85). The top of the composite filter tube (8) is provided with an outlet cap (13) with an air outlet (15). The central shaft (121) The upper end is connected to an adjustment mechanism (14), which includes a gradient sealing plug. When the central shaft (121) moves back and forth, the gradient sealing plug cooperates with the gas outlet (15) to realize the periodic change of the volume of the annular reaction chamber and change the effective cross section of the gas outlet channel, so as to make the airflow pulsate. The central shaft (121) is provided with a through central channel (126) and a side hole (127) connecting the central channel (126). The catalytic chamber (1) is provided with a ventilation gripping mechanism (9). The ventilation gripping mechanism (9) is used to drive the central shaft (121) to rise and fall, and to supply gas to the central channel (126) when the central shaft (121) moves down to a predetermined position. The gas is introduced into the annular reaction chamber through the side hole (127) to complete the backflushing and cleaning.

2. The flue gas purification device for removing ammonia escape from denitrification tail gas according to claim 1, characterized in that: The assembly shaft assembly (12) also includes a positioning ring (125) fixed to the inner wall of the ceramic inner tube (82) and a fixing ring (123) fixedly sleeved on the outside of the central shaft (121). A spring (124) is provided between the fixing ring (123) and the positioning ring (125), and the central shaft (121) slides through the positioning ring (125).

3. The flue gas purification device for removing ammonia escape from denitrification tail gas according to claim 1, characterized in that: The tapered sealing plug has a conical structure, and its insertion depth into the air outlet (15) varies with the stroke of the central shaft (121).

4. The flue gas purification device for removing ammonia escape from denitrification tail gas according to claim 1, characterized in that: The gradient sealing plug has a stepped structure, including an upper plug (141) and a lower plug (142). The bottom of the lower plug (142) is fixedly connected to a connecting crank (143), which is fixedly connected to the central shaft (121). The outer diameter of the lower plug (142) is smaller than that of the upper plug (141).

5. The flue gas purification device for removing ammonia escape from denitrification tail gas according to claim 1, characterized in that: The first catalyst layer (85) is a VW / TiO2-based denitrification catalyst layer, and the second catalyst layer (122) is a Ce-Mn-O x The oxidation catalyst layer, the filter sleeve (84) is a replaceable porous fiber membrane layer, and both ends of the ceramic inner tube (82) and the ceramic outer tube (83) are fixed with assembly rings (81).

6. The flue gas purification device for removing ammonia escape from denitrification tail gas according to claim 1, characterized in that: The catalyst chamber (1) is fixedly connected to a partition (7), and the arrayed composite filter tubes (8) are installed on the partition (7). The partition (7) divides the catalyst chamber (1) into a dust-containing chamber and a clean air chamber.

7. The flue gas purification device for removing ammonia escape from denitrification tail gas according to claim 1, characterized in that: A connecting pipe (5) is provided between the catalyst chamber (1) and the dry tower (2), a discharge pipe (6) is provided at the top of the catalyst chamber (1), and the bottom outlet of the catalyst chamber (1) is connected to the ash silo (3).

8. The flue gas purification device for removing ammonia escape from denitrification tail gas according to claim 1, characterized in that: The ventilation gripping mechanism (9) includes a support plate (91), a connecting frame (92), an electric push rod (93), a gripping plate (94), an air pump (95), and a matching hole (96). The electric push rod (93) is used to drive the gripping plate (94) to rise and fall, so as to control the movement of the central shaft (121). The air outlet of the air pump (95) supplies air to the connecting frame (92), and the air intake passes through the catalytic chamber (1). The connecting frame (92) is connected to the central channel (126). The top of the gripping plate (94) is detachably equipped with an assembly mechanism (11).

9. The flue gas purification device for removing ammonia escape from denitrification tail gas according to claim 8, characterized in that: The bottom of the central shaft (121) is connected to a connecting mechanism (10), which is detachably connected to the assembly mechanism (11). The connecting mechanism (10) includes a threaded conduit (101), an inner ring groove (102), and a "T"-shaped assembly tube (103). The threaded conduit (101) is threaded onto the bottom of the central shaft (121) and communicates with the central channel (126). The inner ring groove (102) is opened on the inner wall of the threaded conduit (101). The "T"-shaped assembly tube (103) is movably sleeved on the bottom of the threaded conduit (101), and the upper end of the "T"-shaped assembly tube (103) is adapted to be fitted into the inner ring groove (102).

10. The flue gas purification device for removing ammonia escape from denitrification tail gas according to claim 9, characterized in that: The assembly mechanism (11) includes an assembly head (111), an internal cavity (112), and a one-way valve (113). The assembly head (111) is detachably mounted on the gripping plate (94). The internal cavity (112) is opened in the assembly head (111). The one-way valve (113) is installed at the bottom of the assembly head (111) and is used to open when the ventilated gripping mechanism (9) supplies air. The top of the assembly head (111) is threadedly connected to the "T"-shaped assembly tube (103). The assembly head (111) is matched with the appropriate matching hole (96).

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