Horizontal denitration tower for landfill gas power generation

Abstract

The present application relates to a kind of landfill gas power generation horizontal SCR denitration tower, tower body is equipped with flue gas distribution plate and catalyst support frame, catalyst support frame has multiple unit partition frames of each catalyst filling unit being placed in layer, catalyst filling unit includes the box body that can be pulled and at least two catalyst units being placed in box body, box body is installed in unit partition frame and with rail interface, baffle on box body end plate is covered at the window of tower body and is connected with tower wall by fastener;Sweeping unit includes upper rail, lower rail and main gas pipe and at least one soot blowing branch pipe, the upper end horizontal roller of soot blowing branch pipe is connected with upper graphite packing;The vertical roller of soot blowing branch pipe lower end is arranged at lower rail, and the lower graphite packing installed on the both sides of the limiting groove of vertical roller is connected with the two sides of lower rail;Ash removal unit includes ash discharge hopper and ash discharge valve.The present application is compact in structure, can realize the rapid removal of dust, reduce dust accumulation, facilitate replacement catalyst unit, reduce maintenance cost and maintenance time.

Description

Technical Field

[0001] This invention relates to a horizontal SCR denitrification tower for landfill gas power generation, belonging to the field of landfill gas technology. Background Technology

[0002] The conventional process for treating landfill gas is: landfill gas → desulfurization → power generation → tail gas SCR → waste heat boiler. Therefore, an SCR (selective catalytic reduction) denitrification tower is required for tail gas denitrification treatment.

[0003] Power generation typically uses generators ranging from 1.0 MW to 1.5 MW, with a flue gas volume of approximately 4200–6000 Nm³ after power generation. 3 / h, because the landfill gas still contains certain impurities, including a small amount of dust and siloxanes that can easily deactivate the catalyst, after power generation, the siloxanes form silica and the initial dust accumulate together on the surface of the catalyst, blocking the catalyst pores and reducing the effective denitrification flow channels. This not only leads to a decrease in denitrification efficiency, but also increases the resistance of the SCR denitrification tower, requiring a reduction in the amount of exhaust gas, which in turn reduces the power generation efficiency.

[0004] After 3-5 months of operation, the maintenance passage before the catalyst in existing SCR denitrification towers becomes partially clogged with ash, and the surface and pores of the catalyst are also clogged with ash. This results in extensive catalyst deactivation, leading to reduced denitrification efficiency and failure to meet environmental standards. Although rake-type soot blowers are used inside the SCR denitrification tower to alleviate ash accumulation and catalyst pore blockage, the accumulated ash cannot be removed from the tower in a timely manner, resulting in a relatively high maintenance frequency.

[0005] Blockage of the catalyst channels reduces the effective flow channels for denitrification, and ash blockage increases system resistance, easily causing generator malfunctions. Therefore, it is necessary to shut down and cool down the system, and then manually open the denitrification tower. Generally, a crane is used to replace the entire catalyst module, resulting in long maintenance and replacement cycles and high replacement costs. Furthermore, deactivated catalyst is classified as hazardous waste, requiring certain disposal costs, thus contributing to high disposal costs.

[0006] The rake-type sootblower in the SCR denitrification tower has its upper end directly installed in the upper channel steel guide rail, and the lower end roller installed in the lower channel steel guide rail. During the movement of the sootblower, it slides against the inside of the channel steel guide rail, forming dry friction. At the same time, the rollers supporting the rollers easily form dry friction with the channel steel guide rails on both sides. The large frictional resistance during purging generates a lot of noise and accelerates the wear between the friction surfaces. Especially when the top of the sootblower is worn through, it cannot effectively blow soot onto the catalyst surface, which will also shorten the service life of the sootblower. In addition, the existing structure is very inconvenient to maintain and disassemble, so the maintenance cost is high. Summary of the Invention

[0007] The purpose of this invention is to provide a landfill gas power generation horizontal SCR denitrification tower with a compact structure, which can achieve rapid dust removal, reduce dust accumulation, facilitate rapid partial or complete replacement of catalyst units, and reduce maintenance costs and maintenance time.

[0008] The technical solution of the present invention to achieve the above objectives is: a landfill gas power generation horizontal SCR denitrification tower, characterized in that: it includes a tower body, multiple catalyst filling units disposed within the tower body, a purging unit located in front of the catalyst filling units, and an ash unloading unit located at the bottom of the tower body.

[0009] The tower body is arranged horizontally, with a flue gas inlet on one side and a flue gas outlet on the other side along the flue gas flow direction. A flue gas distribution plate is provided on the side of the flue gas inlet inside the tower body, and the flue gas distribution plate has guide holes for distributing the flue gas. A catalyst support frame is fixed inside the tower body. The catalyst support frame has multiple unit partitions for stacking and longitudinally placing each catalyst filling unit. Each unit partition has a track for supporting and guiding the catalyst filling unit. The tower wall of the tower body has one window corresponding to one end of the unit partition or two windows corresponding to both ends of the unit partition.

[0010] The catalyst filling unit is used to place catalyst units, including a pull-out box and at least two catalyst units placed inside the box. The box includes a base, an end plate fixed on the base, and at least two compartment partitions. The two sides of the box are flue gas passages. The catalyst units are placed in corresponding compartments separated by the compartment partitions, and the channels of the catalyst units are the same as the flue gas flow. The end plates are provided with baffles that fit against the tower wall around their perimeter. The box is installed in the unit partition frame and connected to the track. The baffles on the end plates cover the windows of the tower and are connected to the tower wall by fasteners.

[0011] The purging unit is used to clean the catalyst unit. It includes an upper guide rail at the top of the tower, a lower guide rail at the bottom, a main gas pipe, and at least one soot blowing branch pipe connected to the main gas pipe. The main gas pipe, located outside the tower, is connected to a telescopic actuator and drives the purging unit to move longitudinally. The soot blowing branch pipe, with sealing plates at both ends, has multiple blowing holes facing the catalyst unit. A support shaft is fixed on the sealing plate at the upper end of the soot blowing branch pipe. A horizontal roller is rotatably mounted on the support shaft and contacts the upper guide rail and rolls along the upper guide rail. The lower plane of the horizontal roller is connected to the upper graphite packing installed on the support shaft. A support seat is fixed on the sealing plate at the lower end of the soot blowing branch pipe. A vertical roller is rotatably mounted on the support seat. A limiting groove on the vertical roller is located at the lower guide rail and rolls along the lower guide rail. The lower graphite packing installed on both sides of the limiting groove of the vertical roller is connected to both sides of the lower guide rail.

[0012] The ash discharge unit is used to receive and discharge the dust inside the tower. It includes an ash discharge hopper and an ash discharge valve. The ash discharge hopper, which is inverted cone shape, is connected to the bottom of the tower body on the front side of the catalyst support frame. An ash discharge valve is installed at the bottom of the ash discharge hopper.

[0013] This invention relates to a landfill gas power generation horizontal SCR denitrification tower. The tower uses a flue gas distribution plate to evenly distribute the inlet flue gas before it enters the catalyst unit for denitrification, thus solving the problem of uneven flue gas distribution in the denitrification system. The invention incorporates a catalyst support frame within the tower, allowing multiple catalyst packing units to be stacked and placed longitudinally, forming multiple layers and rows of reaction layers within the SCR denitrification tower. These reaction layers are independent of each other, ensuring efficient denitrification. Each catalyst packing unit is directly installed within its corresponding unit frame. The catalyst packing unit uses a pull-out box containing at least two catalyst units. After pulling out a single catalyst packing unit, the catalyst units in that layer can be removed one by one, ensuring convenient overall or partial catalyst replacement without the use of electric hoists or cranes. This significantly improves maintenance efficiency and solves the problems of high catalyst replacement frequency, long replacement cycles, and high replacement costs associated with existing catalyst systems.

[0014] This invention features a purging unit located in front of the catalyst filling unit and an ash removal unit at the bottom of the tower. The purging unit cleans the surface and pores of the catalyst, while the ash removal unit promptly removes dust from the tower. Therefore, no dust accumulates in front of the reaction layer, ensuring stable operation of the SCR denitrification tower, reducing downtime for maintenance, and extending the repair cycle. The purging unit uses horizontal rollers that engage with the upper guide rail, with the lower part of the horizontal rollers connected to the upper graphite packing. This reduces the friction between the horizontal rollers and the support shaft due to gravity as they roll along the upper guide rail. Simultaneously, vertical rollers engage with the lower guide rail, with lower graphite packing on both sides of the vertical rollers' limiting grooves. This ensures that the inner surface of the vertical rollers also contacts the graphite packing as they roll along the lower guide rail. When the actuator moves the soot blowing branch pipe, the purging unit moves smoothly, effectively limiting and guiding the movement while reducing friction and noise during the movement of the soot blowing branch pipe. Since the soot blowing branch pipe does not contact the guide rail, the technical problem of the soot blowing branch pipe wearing through and failing to effectively blow soot is completely solved, extending the lifespan of the soot blowing unit. This invention can form an embedded and replaceable graphite packing contact surface, which facilitates the replacement of graphite packing and reduces maintenance and replacement costs.

[0015] This invention can achieve rapid dust removal and rapid partial or complete replacement of catalyst units, reducing dust accumulation, lowering catalyst replacement frequency, reducing production and maintenance costs, extending the power generation efficiency of generator sets, and improving power generation efficiency, which has certain production significance. Attached Figure Description

[0016] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0017] Figure 1 This is a schematic diagram of the structure of a landfill gas power generation horizontal SCR denitrification tower according to the present invention.

[0018] Figure 2 yes Figure 1 A top view of the top of the dismantling tower and the upper guide rail.

[0019] Figure 3 This is a schematic diagram of the purging unit of the present invention.

[0020] Figure 4 yes Figure 3 A magnified structural diagram at point I.

[0021] Figure 5 yes Figure 3 Enlarged structural diagram at point II.

[0022] Figure 6 This is a schematic diagram of the catalyst filling unit of the present invention.

[0023] Figure 7 yes Figure 6 A side view structural diagram.

[0024] Wherein: 1—Tower body, 1-1—Front tower body, 1-11—Flue gas inlet, 1-2—Rear tower body, 1-21—Flue gas outlet, 1-3—Window, 2—Purge unit, 2-1—Main air pipe, 2-2—Connecting main pipe, 2-3—Soot blowing branch pipe, 2-31—Sealing plate, 2-32—Purge hole, 2-4—Support shaft, 2-41—Wheel shaft section, 2-42—Lower annular groove, 2-5—Support seat, 2-6—Vertical roller, 2-61—Limiting groove, 2-62—Side annular groove, 2-7—Upper graphite packing, 2-8—Lower graphite packing, 2-9 1. Horizontal roller; 2. Flue gas distribution plate; 3. Lower guide rail; 4. Ash discharge unit; 5. Ash discharge hopper; 6. Manual slide gate valve; 7. Rotary star valve; 8. Upper guide rail; 9. Catalyst filling unit; 10. Catalyst unit; 11. Box body; 22. Bin partition; 23. End plate; 24. Base; 25. Ceramic fiber gasket; 26. Cover plate; 27. Catalyst support frame; 28. Column; 29. ​​Longitudinal beam; 20. Intermediate support beam; 21. Tower; 22. Sealing seat; 33. Pressure cover. Detailed Implementation

[0025] See Figure 1 , Figure 2 As shown, a landfill gas power generation horizontal SCR denitrification tower of the present invention includes a tower body 1, multiple catalyst filling units 7 and purging units 2 disposed inside the tower body 1, and an ash unloading unit 5 located outside the tower body 1.

[0026] See Figure 1 , Figure 2 As shown, the tower body 1 of this invention is arranged horizontally. The tower body 1 has a flue gas inlet 1-11 on one side and a flue gas outlet 1-21 on the other side along the flue gas flow direction. The flue gas inlet 1-11 on the tower body 1 is connected to the inlet flue. A dual-fluid spray gun is installed on the inlet flue, through which urea solution or ammonia water is sprayed into the high-temperature flue gas. The ammonia or ammonia water generated by the pyrolysis of the urea solution evaporates and reacts with nitrogen oxides in the flue gas, forming ammonia gas adsorbed on the catalyst surface and undergoing an SCR denitrification reaction. See Figure 1 , 2 As shown, a flue gas distribution plate 3 is provided on one side of the flue gas inlet 1-11 inside the tower body 1 of the present invention. The high-temperature flue gas is controlled to 400-450°C by water spraying and other measures before entering the tower body 1. The flue gas distribution plate 3 is provided with guide holes for distributing the flue gas. The high-temperature flue gas is distributed through the flue gas distribution plate 3 so that the flue gas enters the corresponding catalyst filling unit 7 more evenly for denitrification reaction.

[0027] See Figure 1 , 2 As shown, the tower body 1 of the present invention includes a gradually expanding conical or pyramidal front tower body 1-1, a main tower body, and a gradually narrowing conical or pyramidal rear tower body 1-2. The front end of the front tower body 1-1 is a flue gas inlet 1-11, and the rear end of the rear tower body 1-2 is a flue gas outlet 1-21. The main tower body is fixed on the tower frame 9, and a maintenance manhole is provided in front of the catalyst support frame 8 for convenient maintenance. The flue gas distribution plate 3 is fixed at the front end of the main tower body. The flue gas distribution plate 3 is provided with horizontally or vertically striped baffles, and guide holes are formed between each pair of baffles. The hole spacing of the guide holes in the middle of the flue gas distribution plate 3 is smaller than that of the guide holes on the other two sides. When the flue gas enters the front tower body 1-1 inside the tower body 1, the flue gas flow rate is reduced, and the flue gas diffuses to the flue gas distribution plate 3 in the front tower body 1-1. Since the hole spacing of the guide holes in the middle of the flue gas distribution plate 3 is smaller than that in other parts, the resistance of the flue gas flow in the middle part is increased, so that the large flow of flue gas in the middle is distributed to both sides, and the flue gas is evenly distributed to each catalyst filling unit 7 for denitrification treatment. In this invention, the central guide hole of the flue gas distribution plate 3 is between 30 and 60 mm, and the guide holes of the remaining parts are between 60 and 100 mm. For example, the guide holes of the central 1 / 3 partition are between 30 and 60 mm, and the guide holes of the remaining 1 / 3 side partitions are between 60 and 100 mm, which is conducive to the uniform distribution of fluid. For example, the central guide hole is 50 mm and the two side guide holes are 90 mm. In this invention, flat steel with a width of 50 mm can be used to divide and form the guide holes. The partition can also be arranged horizontally and vertically.

[0028] See Figure 1 , Figure 2As shown, a catalyst support frame 8 is fixed inside the tower body 1 of the present invention. The catalyst support frame 8 has multiple unit frames for stacking and longitudinally placing each catalyst filling unit 7. The catalyst support frame 8 is provided with multiple layers of unit frames, which can hold multiple layers of catalyst filling units 7, realizing multiple layers and multiple rows of reaction layers inside the tower body 1. Each unit frame of the present invention is provided with a track for supporting and guiding the catalyst filling unit 7. The tower wall of the tower body 1 is provided with one window 1-3 corresponding to one end of the unit frame or two windows 1-3 corresponding to both ends of the unit frame, so that the catalyst filling unit 7 can be installed on the unit frame from one window 1-3 to realize single-layer single-sided insertion. The catalyst filling unit 7 can also be installed on the unit frame from two opposite windows 1-3 to realize single-layer double-sided insertion, which can reduce the weight of a single catalyst filling unit 7 and facilitate manual operation. Therefore, when the catalyst is partially or completely replaced, only the corresponding catalyst filling unit 7 needs to be pulled out from the tower body 1.

[0029] See Figure 1 , 2 As shown, the catalyst support frame 8 of the present invention includes multiple columns 8-1 and multiple unit frames formed by horizontal beams and longitudinal beams 8-2 welded to each pair of columns 8-1. Each column 8-1 is connected to the tower body 1. The columns 8-1 can be made of angle steel, channel steel, rectangular steel, etc., and are fixed in the main tower body. The horizontal beams and longitudinal beams 8-2 are also made of angle steel or channel steel and are welded to the corresponding columns 8-1 to form multiple independent unit frames supporting the space of each catalyst filling unit 7. In order to improve the strength of the catalyst support frame 8, the present invention also fixes an intermediate support beam 8-3 between the longitudinal beams 8-2 and / or the horizontal beams. The intermediate support beam 8-3 can be arranged horizontally or vertically. The longitudinal beams 8-2 on both sides of the present invention can serve as tracks, and the intermediate support beam 8-3 in the longitudinal direction can also serve as tracks.

[0030] See Figure 1 , Figure 2 As shown, the catalyst filling unit 7 of the present invention is used to place catalyst units 7-1, including a pull-out box 7-2 and at least two catalyst units 7-1 placed inside the box 7-2. Figure 6 , Figure 7 As shown, the housing 7-2 includes a base 7-23, an end plate 7-22 fixed to the base 7-23, and at least two compartment plates 7-21. The two sides of the housing 7-2 are flue gas passages. The housing 7-2 has no side plates. The catalyst unit 7-1 is placed in a corresponding compartment separated by the compartment plates 7-21. The channels of the catalyst unit 7-1 flow in the same direction as the flue gas. The flue gas enters the channels of the catalyst unit 7-1 from the front of the housing 7-2, flows through the catalyst unit 7-1, then flows to the other side into the rear tower 1-2, and finally exits from the flue gas outlet 1-21. See [link / description missing]. Figure 1 , 2As shown, the end plate 7-22 of this invention is provided with baffles around its perimeter that fit against the tower wall. The baffles are between 30 and 50 mm in diameter. When replacing the catalyst unit, it is not necessary to lift out the catalyst support frame 8; the box 7-2 can be manually pulled or pushed. Therefore, the entire or partial replacement of the catalyst unit can be performed without using an electric hoist or crane. See Figure 1 , Figure 2 As shown, the housing 7-2 is installed within the unit partition and connected to the track. The housing 7-2 moves along the track within the unit partition. The baffle on the end plate 7-22 covers the windows 1-3 of the tower body 1 and is connected to the tower wall by fasteners to ensure that the flue gas does not leak. The housing 7-2 of this invention can be welded from angle iron or other shaped steel and plates. Due to the use of the partition plate 7-21, the catalyst filling units 7 do not interfere with each other.

[0031] See Figure 6 , Figure 7 As shown, the end plate 7-22 of the box body 7-2 of the present invention is provided with an operating handle for easy operation. The base 7-23 of the box body 7-2 includes a surrounding frame and multiple support beams fixed within the frame. Alternatively, the base 7-23 may include a surrounding frame and a base plate fixed to the frame. Sliding elements that mate with the tracks on the unit partition are provided on both sides of the frame or on the support beams. The base 7-23 of the box body 7-2 of the present invention has a plate-like structure. The bottom of the plate is provided with sliding elements that mate with the tracks on the unit partition. These sliding elements can be rollers or slide rails, which can reduce movement resistance when pulling the box body 7-2. See Figure 6 , Figure 7As shown, the housing 7-2 of this invention is provided with 3 to 8 compartments 7-21, forming 3 to 8 compartments, which can hold multiple catalyst units 7-1, so that the catalyst units 7-1 form a multi-layered, multi-row reaction layer to denitrify the flue gas entering the main tower. To reduce the impact on the catalyst units 7-1, the inner side of the end plate 7-22 and the two sides of the compartments 7-21 are also provided with high-temperature resistant ceramic fiber gaskets 2-24. The thickness of the ceramic fiber gaskets 2-24 is 1 to 3 mm. Ceramic fiber gaskets 2-24 can also be installed between the top of the catalyst unit 7-1 and the cover plate 7-25, so that the catalyst units 7-1 do not affect each other. The catalyst unit 7-1 of this invention is an industrial honeycomb vanadium-titanium catalyst with a pitch of 4.2–5.9 mm, a cross-sectional dimension of 150 mm × 150 mm, and a length of 300–800 mm. Therefore, the weight of a single catalyst unit 7-1 is 3–8 kg, and the total weight of the catalyst packing unit 7 is approximately 9–64 kg. Due to the significant reduction in the weight of the catalyst packing unit 7, it is convenient to manually push and pull the catalyst packing unit 7. After the catalyst packing unit 7 is removed, the catalyst units 7-1 in each compartment can be taken out one by one. After the catalyst is easily deactivated in the SCR denitrification tower, the catalyst packing unit 7 can be manually removed. Without the use of electric hoists or cranes, it is convenient to replace the entire catalyst or part of it.

[0032] See Figures 1-5 As shown, the purging unit 2 of the present invention is used to clean the catalyst unit 7-1. It includes an upper guide rail 6 at the top of the tower body 1, a lower guide rail 4 at the bottom, a main air pipe 2-1, and at least one soot blowing branch pipe 2-3 connected to the main air pipe 2-1. The main air pipe 2-1, which is located outside the tower body 1, is connected to a telescopic actuator and drives the purging unit 2 to move longitudinally. The telescopic actuator, which is installed on the tower, is connected to a movable seat on the main air pipe 2-1. The telescopic actuator can be an electric actuator or a pneumatic actuator, such as an electric push rod or a box-type telescopic mechanism, which are mature industrial actuators. The telescopic operation of the actuator drives the soot blowing branch pipe to move along the upper and lower guide rails.

[0033] See Figure 1 As shown, the tower body 1 of the present invention also has a pipe sleeve sealing assembly, which includes a sealing seat 10 and a pressure cap 11. The sealing seat 10 is fixed outside the tower body 1 at the point where the main gas pipe 2-1 passes through. The sealing element set in the sealing seat 10 is fitted onto the main gas pipe 2-1, and the pressure cap 11 fitted onto the main gas pipe 2-1 is connected to the sealing seat 10 by fasteners. One end of the pressure cap 11 presses against the sealing element. During the blowing process, the main gas pipe 2-1 can maintain a good seal by moving, ensuring that the flue gas does not leak.

[0034] See Figures 1-5As shown, the soot blowing branch pipe 2-3 with sealing plates 2-31 at both ends of the present invention has multiple blowing holes 2-32 facing the catalyst unit 7-1. The distance between the blowing holes 2-32 on the soot blowing branch pipe 2-3 and the front end face of the catalyst unit 7-1 is 40-60mm. The hole spacing h of the blowing holes 2-32 on the soot blowing branch pipe 2-3 is between 10 and 30mm. The hole diameter of the blowing holes 2-32 is between 1.0mm and 4.0mm. For example, if the distance between the blowing holes 2-32 on the soot blowing branch pipe 2-3 and the front end face of the catalyst unit is 50mm, the hole spacing of the blowing holes 2-32 is 120mm, and the hole diameter of the blowing holes 2-32 is 3mm, each column of catalyst unit 7-1 is blown one by one during purging. The soot blowing air source of the present invention is compressed air at 2-4 bar after oil removal, water removal, and dust removal. The compressed air for soot blowing can be heated to above 100°C. The clean hot gas enters the soot blowing branch pipe 2-3 from the main air pipe 2-1, and is then sprayed out through the blow holes 2-32 on the soot blowing branch pipe 2-3. The impurities and dust from the landfill gas on the surface of the SCR catalyst and the silica particles formed by siloxane power generation are blown out. Some of the dust falls into the ash discharge hopper 5-1, and some is blown out of the catalyst channels and dispersed with the flue gas, thus avoiding catalyst blockage and delaying the catalyst life.

[0035] This invention employs program-controlled purging, with an adjustable purging cycle A (min), adjustable purging interval B (min), and adjustable purging step C (s). The system performs purging at intervals. Each purging cycle consists of the telescopic actuator operating for C (s), simultaneously opening the compressed air pneumatic valve for C (s), followed by an interval of B min to replenish compressed air from the compressed air tank. The actuator continues operating, and the compressed air pneumatic valve remains open until the purging branch pipe 2-3 reaches the limit switch of that reaction layer. Then, the system automatically resets without purging and begins purging the second multi-layer reaction layer, continuing until all reaction layers have been purged.

[0036] See Figure 3 As shown, the main air pipe 2-1 of the present invention is connected to the soot blowing branch pipe 2-3 via the connecting trunk pipe 2-2. The connecting trunk pipe 2-2 has a split connecting flange in the middle. Both ends of the connecting trunk pipe 2-2 are fixedly connected to the soot blowing branch pipe 2-3 and the main air pipe 2-1, respectively. Since the connecting trunk pipe 2-2 is a split structure, one end is welded and fixed to the main air pipe 2-1, and the other end is welded and fixed to the soot blowing branch pipe 2-3. The connecting flange in the middle of the connecting trunk pipe 2-2 is connected by fasteners, which facilitates the maintenance and installation of the pipeline.

[0037] See Figure 3 , 4As shown, a support shaft 2-4 is fixed on the sealing plate 2-31 at the upper end of the soot blowing branch pipe 2-3 of the present invention. A horizontal roller 2-9 is rotatably mounted on the support shaft 2-4, contacts the upper guide rail 6, and rolls along the upper guide rail 6. The lower plane of the horizontal roller 2-9 is in contact with the upper graphite packing 2-7 mounted on the support shaft 2-4. The horizontal roller 2-9 rests flat on the upper graphite packing 2-7 by its own weight, avoiding dry friction between the bottom of the horizontal roller 2-9 and the lower end face of the shaft caused by gravity, thus achieving friction reduction and noise reduction. See Figure 4 As shown, the support shaft 2-4 has a wheel axle section 2-41 with a shaft diameter smaller than that of the support shaft 2-4. The wheel axle section 2-41 is located in the upper middle part of the support shaft 2-4. A horizontal roller 2-9 is rotatably mounted on the wheel axle section 2-41. The upper part of the wheel axle section 2-41 also has a portion of the support shaft 2-4 with a larger diameter. This portion can be welded to the wheel axle section after the horizontal roller 2-9 is installed, or it can be a separate structure and screwed onto the wheel axle section. The support shaft 2-4 has a lower annular groove 2-42 at the bottom of the wheel axle section 2-41. An upper graphite packing 2-7 is installed in the lower annular groove 2-42. The lower annular groove 2-42 can hold a 3mm to 5mm square graphite packing. The top surface of the upper graphite packing 2-7 extends 2 to 3mm beyond the top surface of the lower annular groove 2-42. The horizontal roller 2-9 presses down on the upper graphite packing 2-7 by gravity and is not easily connected to the support shaft 2-4.

[0038] See Figure 4 As shown, to reduce the shaking of the soot blowing branch pipe 2-3 during the blowing process and further improve the reliability of operation, the present invention has two support shafts 2-4 fixed on the top sealing plate 2-31 of the soot blowing branch pipe 2-3. Horizontal rollers 2-9 are correspondingly installed on each support shaft 2-4. An upper guide rail 6 is set between the two horizontal rollers 2-9, so that the two horizontal rollers 2-9 roll stably along the two planes of an upper guide rail 6. The upper guide rail 6 is a planar guide rail. The support shaft 2-4 also has a maintenance gap H on the wheel axle section 2-41, which allows the horizontal rollers 2-9 to move upward. The maintenance gap H is greater than the height of the upper graphite packing 2-7. If the wheel axle section 2-41 has a gap of more than 5mm above the horizontal rollers 2-9, the upper graphite packing 2-7 can be replaced by moving the horizontal rollers 2-9 axially upward by 5mm, thereby reducing maintenance costs and saving replacement time.

[0039] See Figure 5 As shown, in this invention, a support seat 2-5 is fixed to the sealing plate 2-31 at the lower end of the soot blowing branch pipe 2-3. A vertical roller 2-6 is rotatably mounted on the support seat 2-5. The support seat 2-5 can be welded to the sealing plate 2-31, and a shaft pin passes through the vertical roller 2-6 and is fixed to the support seat 2-5, allowing the vertical roller 2-6 to rotate freely. See Figure 5As shown, the limiting groove 2-61 on the vertical roller 2-6 of the present invention is set at the lower guide rail 4 and rolls along the lower guide rail 4. The lower graphite packing 2-8 installed on both sides of the limiting groove 2-61 of the vertical roller 2-6 is connected to both sides of the lower guide rail 4. The lower guide rail 4 of the present invention is a guide rail with an arc-shaped curved surface, and round steel can be used as the lower guide rail 4. The side ring groove 2-62 of the limiting groove 2-61 can place a 3mm to 5mm square graphite packing and press the graphite packing into it, so that during the rolling of the vertical roller 2-6 along the lower guide rail 4, the two sides of the lower guide rail 4 only contact the lower graphite packing 2-8, thereby reducing friction and noise.

[0040] See Figure 1 As shown, the ash discharge unit 5 of this invention is used to receive and discharge dust from the tower body 1. It includes an ash discharge hopper 5-1 and an ash discharge valve. The inverted cone-shaped ash discharge hopper 5-1 communicates with the bottom of the tower body 1 on the front side of the catalyst support frame 8. An ash discharge valve is installed at the lower part of the ash discharge hopper 5-1, so that the blown-out impurities, dust, and silica particles fall into the ash discharge hopper 5-1, realizing rapid dust removal and keeping the surface and pores of the catalyst clean, thus reducing the frequency of catalyst replacement. The ash discharge hopper 5-1 of this invention is set at the bottom of each column of catalyst units 7-1, so that each ash discharge hopper 5-1 corresponds to each column of catalyst units 7-1. The lower part of the ash discharge hopper 5-1 of this invention is provided with an ash discharge pipe. The ash discharge valve includes a manual slide valve 5-2 and a star-shaped unloading valve 5-3. The manual slide valve 5-2 is installed on the ash discharge pipe and is normally open. It is only closed during maintenance. The bottom of the ash discharge pipe is connected to the star-shaped unloading valve 5-3. The bottom of the star-shaped unloading valve 5-3 is connected to a high-temperature resistant sealed ash container, which is periodically removed by a hydraulic trolley or forklift.

[0041] A landfill gas treatment project uses a single 1.0 MPa generator set with an exhaust gas temperature of 420–450°C and a gas volume of approximately 4200 Nm³. 3 / h, denitrification treatment is carried out using a 10% urea solution as the denitrification reducing agent. Example

[0042] The SCR denitrification tower of this invention is used, and catalyst packing units 7 are installed on both sides, see... Figure 1 and Figure 2 As shown, each catalyst packing unit 7 contains four catalyst units 7-1, with a catalyst pitch of 4.9 mm. Each catalyst unit 7-1 measures 150 mm × 150 mm × 500 mm, weighs 8 kg, and has a volume of 0.01125 m³. 3 There are a total of 16 catalyst packing units 7, comprising 64 catalyst units 7-1. The reaction layer consists of 8 layers and 8 columns. The total weight of the catalyst is 81 kg, and the total volume is 0.72 m³. 3The bottom of tower body 1 does not have an ash removal unit 5, but a purging unit 2 is installed before the catalyst filling unit 7. The ash blowing cycle is 2 hours / cycle, the ash blowing step length is 10 seconds, and the ash blowing interval is 2 minutes. During the first five months of operation, it can stably reduce NOx from 500 mg / Nm³. 3 Reduced to 50 mg / Nm 3 Subsequently, the purging unit 2 experienced jamming. Inspection revealed a 100mm layer of ash buildup at the front, completely covering the vertical rollers 2-6 and lower guide rail of the purging unit 2. The unit was shut down for three days for dust cleaning inside the denitrification tower. Subsequent operation continued, with the catalyst used for a total of seven months, during which NOx rose to 135mg / Nm³. 3 In the comparison of denitrification efficiency, the catalyst deactivation rate was 30%. Example

[0043] The number of catalyst units 7-1 is the same as in Example 1, but without a purging unit. Instead, an ash removal unit 5 is installed before the catalyst filling unit 7, with ash removal occurring once every 4 hours for 5 minutes each time. During the first two months of operation, NOx levels can be stably reduced from 500 mg / Nm³. 3 Reduced to 50 mg / Nm 3 In the third month, NOx rose to 70 mg / Nm³. 3 In the sixth month of operation, NOx rose to 200 mg / Nm³. 3 In the comparison of denitrification efficiency, the catalyst deactivation rate was 44%. Example

[0044] The catalyst unit 7-1 in Example 1 has the same number of units, but a purging unit 2 is provided before the catalyst filling unit 7, and an ash removal unit 5 is also provided. The purging unit 2 has a purging cycle of 2 hours / cycle, a purging step length of 10 seconds, and a purging interval of 2 minutes. The ash removal unit discharges material once every 54 hours, with each discharge lasting 5 minutes. During the first ten months of operation, NOx levels can be stably reduced from 500 mg / Nm³. 3 Reduced to 50 mg / Nm 3 Then NOx rose to 100 mg / Nm³. 3 In the comparison of denitrification efficiency, the catalyst deactivation was 22%.

[0045] Then, catalyst unit 7-1 was replaced. Two catalyst units 7-1 were replaced in each catalyst packing unit 7, spaced two apart. The replaced catalyst units 7-1 within every two layers of catalyst packing units 7 were staggered. A total of 0.36m of catalyst units were replaced. 3 That is, 50% catalyst, and then continued to operate, and operated stably and met the standards for four months.

[0046] Comparative Example

[0047] The existing SCR denitrification tower is used, employing a single reaction layer with a packing depth of approximately 0.72m. 3The catalyst has a pitch of 4.9mm and is a non-standard modular unit measuring 1280mm × 1280mm × 700mm. It does not include a purging unit or an ash removal unit. During the first month of operation, it can stably reduce NOx levels from 450mg / Nm³. 3 Reduced to 50 mg / Nm 3 Below, NOx rose to 65 mg / Nm³ in the second month of operation. 3 After three months of operation, NOx levels rose to 88 mg / Nm³. 3 In the sixth month of operation, NOx rose to 225 mg / Nm³. 3 The catalyst was replaced, and it was found that 90% of the surface of the old catalyst was covered with dust, and 200mm of dust accumulated at the inlet of the reaction layer. According to the denitrification efficiency comparison, the catalyst was deactivated by 50%.

[0048] As can be seen from the comparison, the SCR denitrification tower of this invention can improve the service life of the catalyst, reduce the frequency of catalyst replacement, reduce downtime maintenance time, improve power generation efficiency, and extend production time.

Claims

1. A landfill gas power generation horizontal SCR denitrification tower, characterized in that: It includes a tower body (1), multiple catalyst filling units (7) set inside the tower body (1), a purging unit (2) located in front of the catalyst filling unit (7), and an ash unloading unit (5) located at the bottom of the tower body (1). The tower body (1) is arranged horizontally. The tower body (1) has a flue gas inlet (1-11) on one side and a flue gas outlet (1-21) on the other side along the flue gas flow direction. A flue gas distribution plate (3) is provided inside the tower body (1) on one side of the flue gas inlet (1-11). The flue gas distribution plate (3) is provided with guide holes for distributing the flue gas. A catalyst support frame (8) is fixed inside the tower body (1). The catalyst support frame (8) has multiple unit partitions for stacking and longitudinally placing each catalyst filling unit (7). Each unit partition is provided with a track for supporting and guiding the catalyst filling unit (7). The tower wall of the tower body (1) is provided with a window (1-3) corresponding to one end of the unit partition or two windows (1-3) corresponding to both ends of the unit partition. The catalyst filling unit (7) is used to place the catalyst unit (7-1), including a pull-out box (7-2) and at least two catalyst units (7-1) placed in the box (7-2). The box (7-2) includes a base (7-23), an end plate (7-22) fixed on the base (7-23), and at least two compartment plates (7-21). The two sides of the box (7-2) are flue gas channels. The catalyst unit (7-1) is placed in the compartment plate (7-21) to isolate the corresponding compartment. The channel of the catalyst unit (7-1) is in the same direction as the flue gas flow. The end plate (7-22) is provided with baffles that fit against the tower wall around its perimeter. The box (7-2) is installed in the unit frame and connected to the track. The baffles on the end plate (7-22) cover the window (1-3) of the tower body (1) and are connected to the tower wall by fasteners. The purging unit (2) is used to clean the catalyst unit (7-1), including an upper guide rail (6) at the top of the tower body (1), a lower guide rail (4) at the bottom, a main gas pipe (2-1), and at least one soot blowing branch pipe (2-3) connected to the main gas pipe (2-1). The main gas pipe (2-1) located outside the tower body (1) is connected to the telescopic actuator and drives the purging unit (2) to move longitudinally. The soot blowing branch pipe (2-3) with sealing plates (2-31) at both ends faces towards Multiple blowing holes (2-32) are provided for the catalyst unit (7-1). A support shaft (2-4) is fixed on the sealing plate (2-31) at the upper end of the soot blowing branch pipe (2-3). A horizontal roller (2-9) is rotatably mounted on the support shaft (2-4) and contacts the upper guide rail (6) and rolls along the upper guide rail (6). The lower plane of the horizontal roller (2-9) is connected to the upper graphite packing (2-7) mounted on the support shaft (2-4). The sealing plate (2-31) at the lower end of the soot blowing branch pipe (2-3) is fixed on the catalyst unit (7-1). 1) A support base (2-5) is fixed on the upper part, and a vertical roller (2-6) is rotatably mounted on the support base (2-5). The limiting groove (2-61) on the vertical roller (2-6) is set at the lower guide rail (4) and rolls along the lower guide rail (4). The lower graphite packing (2-8) installed on both sides of the limiting groove (2-61) of the vertical roller (2-6) is connected to both sides of the lower guide rail (4). Two support shafts (2-4) are fixed on the sealing plate (2-31) at the top of the soot blowing branch pipe (2-3). Each support shaft (2-4) has a wheel axle section (2-41) with a shaft diameter smaller than that of the support shaft (2-4). Horizontal rollers (2-9) are installed on the wheel axle sections (2-41) of each support shaft (2-4). The upper guide rail (6) is set between the two horizontal rollers (2-9). The support shaft (2-4) also has a maintenance gap H on the wheel axle section (2-41) that allows the horizontal rollers (2-9) to move upward. The maintenance gap H is greater than the height of the upper graphite packing (2-7). The ash discharge unit (5) is used to receive and discharge the dust in the tower body (1). It includes an ash discharge hopper (5-1) and an ash discharge valve. The ash discharge hopper (5-1), which is inverted cone shape, is connected to the bottom of the tower body (1) on the front side of the catalyst support frame (8). An ash discharge valve is installed at the bottom of the ash discharge hopper (5-1).

2. The landfill gas power generation horizontal SCR denitrification tower according to claim 1, characterized in that: The tower body (1) includes a gradually expanding conical or pyramidal front tower body (1-1), a main tower body, and a gradually narrowing conical or pyramidal rear tower body (1-2). The front end of the front tower body (1-1) is a flue gas inlet (1-11), and the rear end of the rear tower body (1-2) is a flue gas outlet (1-21). The flue gas distribution plate (3) is fixed to the front end of the main tower body. The flue gas distribution plate (3) has horizontally or vertically distributed partitions, and guide holes are formed between each pair of partitions. The hole spacing of the guide holes in the middle of the flue gas distribution plate (3) is smaller than the hole spacing of the guide holes on the other two sides.

3. A landfill gas power generation horizontal SCR denitrification tower according to claim 2, characterized in that: The spacing between the central guide holes is between 30 and 60 mm, while the spacing between the remaining guide holes is between 60 and 100 mm.

4. The landfill gas power generation horizontal SCR denitrification tower according to claim 1, characterized in that: The catalyst support frame (8) includes multiple columns (8-1) and multiple unit frames consisting of multiple rows of crossbeams and longitudinal beams (8-2) welded to each pair of columns (8-1). The columns (8-1) are fixedly connected to the tower body (1), and an intermediate support beam (8-3) is fixed between the longitudinal beams (8-2) and / or the crossbeams. The longitudinal beams (8-2) or the longitudinal intermediate support beams (8-3) have tracks.

5. A landfill gas power generation horizontal SCR denitrification tower according to claim 1, characterized in that: The end plate (7-22) of the box body (7-2) is provided with an operating handle. The base (7-23) of the box body (7-2) includes a frame around the perimeter and multiple support beams or base plates fixed inside the frame. The sides of the frame or the support beams are provided with sliding parts that match the rails on the unit partition. The box body (7-2) is provided with 3 to 8 compartment plates (7-21). The inner side of the end plate (7-22) and the two sides of the compartment plates (7-21) are also provided with high-temperature resistant ceramic fiber gaskets (2-24). The cover plate (7-25) is installed on the compartment plates (7-21).

6. A landfill gas power generation horizontal SCR denitrification tower according to claim 1, characterized in that: The catalyst unit (7-1) is an industrial honeycomb vanadium-titanium catalyst with a pitch of 4.2 to 5.9 mm, a cross-sectional dimension of 150 mm × 150 mm, and a length of 300 to 800 mm.

7. A landfill gas power generation horizontal SCR denitrification tower according to claim 1, characterized in that: The main air pipe (2-1) is connected to the soot blowing branch pipe (2-3) via the connecting trunk pipe (2-2). The connecting trunk pipe (2-2) has a split connecting flange in the middle. The two ends of the connecting trunk pipe (2-2) are fixedly connected to the soot blowing branch pipe (2-3) and the main air pipe (2-1) respectively. The connecting flange in the middle of the connecting trunk pipe (2-2) is connected by fasteners.

8. A landfill gas power generation horizontal SCR denitrification tower according to claim 1, characterized in that: The distance between the blow hole (2-32) on the soot blowing branch pipe (2-3) and the front end face of the catalyst unit (7-1) is between 40-60 mm, the hole spacing h of the blow hole (2-32) on the soot blowing branch pipe (2-3) is between 10-30 mm, and the hole diameter of the blow hole (2-32) is between 1.0 mm and 4.0 mm.

9. A landfill gas power generation horizontal SCR denitrification tower according to claim 1, characterized in that: The tower body (1) also has a pipe sleeve sealing assembly, which includes a sealing seat (10) and a pressure cap (11). The sealing seat (10) is fixed outside the tower body (1) where the main gas pipe (2-1) passes through. The sealing element set in the sealing seat (10) is fitted on the main gas pipe (2-1). The pressure cap (11) fitted on the main gas pipe (2-1) is connected to the sealing seat (10) by fasteners. One end of the pressure cap (11) is pressed against the sealing element.

10. A landfill gas power generation horizontal SCR denitrification tower according to claim 1, characterized in that: The ash discharge hopper (5-1) is located at the bottom of each catalyst unit (7-1). The lower part of the ash discharge hopper (5-1) is provided with an ash discharge pipe. The ash discharge valve includes a manual slide valve (5-2) and a star-shaped discharge valve (5-3). The manual slide valve (5-2) is installed on the ash discharge pipe and is normally open. The bottom of the ash discharge pipe is connected to the star-shaped discharge valve (5-3).

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