Process system for solid recovery of a caustic recovery boiler melt

Abstract

This utility model discloses a solid-state recovery and re-dissolution treatment system for molten material from an alkali recovery boiler, relating to the field of alkali recovery boiler technology. The treatment system includes a fully enclosed chute, a cooling device, a crushing device, and a dissolving device arranged sequentially along the material flow direction. The dissolving device is equipped with a filtration and exhaust assembly and a flushing assembly for rinsing the filtration and exhaust assembly. It also includes a waste heat recovery pipeline for utilizing the demineralized water from the alkali recovery boiler, which is connected to the fully enclosed chute and the cooling device. In this system, the molten material first enters the cooling device for heat exchange, and after cooling, it enters the dissolving device to contact and dissolve with dilute white liquid. The cooling process of the molten material no longer generates large amounts of water vapor; water vapor is reduced by more than 90%, and there is no noise pollution or safety hazard caused by a molten material-water explosion.

Description

Technical Field

[0001] This utility model relates to the field of alkali recovery boiler technology, specifically to a treatment system for the solid recovery and redissolution of molten material from an alkali recovery boiler. Background Technology

[0002] In the alkali recovery process of the pulp and paper industry, the molten material (mainly composed of sodium carbonate, sodium sulfide, etc.) produced by the combustion of the alkali recovery boiler (referred to as "alkali furnace" or "black liquor furnace") enters the dissolving tank through the molten material chute at the bottom of the furnace and is directly mixed with the dilute white liquor and cooled and dissolved. The resulting green liquor enters the causticizing section, and the alkali liquor generated after causticizing returns to the pulp production system.

[0003] Existing alkali furnace molten material processing technologies have the following key drawbacks:

[0004] (1) Safety hazards: The open chute design is easily blocked by cold air, and the direct contact between the high-temperature molten material and the green liquid can easily cause a molten material-water contact explosion;

[0005] (2) Waste of heat energy: The sensible heat of the molten material at 800-900℃ is not fully recovered;

[0006] (3) Pollution and energy consumption: Before entering the melting tank, the molten material needs to be dispersed by steam, which leads to high energy consumption. Direct cooling of the molten material in the melting tank will generate a large amount of high-temperature steam (noise up to 90dB) and dust.

[0007] As gas is discharged from the existing dissolving tank, the dust carried by the gas adheres to the exhaust pipe. The dust carried by the gas is mainly sodium salt, and the exhaust gas has a high moisture content, which makes it easy to condense, thereby accelerating the blockage and corrosion of the pipe and affecting the normal operation of the equipment.

[0008] Therefore, it is necessary to develop a solid-state recovery and redissolution treatment system for alkali recovery boiler molten material, which eliminates the need for steam dispersion of the molten material, avoids noise pollution and safety hazards such as molten material-water explosion, and prevents the generation of large amounts of water vapor during the cooling process. At the same time, the system purifies the gas discharged through the dissolution tank, reduces the dust content of the gas, increases its dryness, reduces the risk of system pipeline corrosion, and extends the continuous operation cycle of the system. Summary of the Invention

[0009] The purpose of this invention is to address the shortcomings of the aforementioned background technology and provide a solid-state recovery and re-dissolution treatment system for molten material from an alkali recovery boiler. This system eliminates the need for steam to disperse the molten material, avoids noise pollution and safety hazards associated with molten material-water explosions, and prevents the generation of large amounts of water vapor during the cooling process. Simultaneously, it purifies the gas discharged through the dissolution tank, reducing dust content, increasing dryness, lowering the risk of system pipeline corrosion, and extending the system's continuous operation cycle.

[0010] The technical solution of this utility model is: a solid recovery and re-dissolution treatment system for molten material from an alkali recovery boiler, characterized in that it includes a fully enclosed chute, a cooling device, a crushing device, and a dissolving device arranged sequentially along the material flow direction, wherein the dissolving device is equipped with a filter exhaust assembly and a flushing assembly for flushing the filter exhaust assembly.

[0011] It also includes a waste heat recovery pipeline for utilizing the demineralized water from the alkali recovery boiler. The waste heat recovery pipeline is connected to a fully enclosed chute and a cooling device for introducing demineralized water for cooling.

[0012] Preferably, the cooling device includes a primary cooling device and a primary and secondary cooling device for the conveying equipment arranged along the material flow direction. Each of the fully enclosed chute, the primary cooling device, and the primary and secondary cooling devices for the conveying equipment is provided with a coolant inlet and a coolant outlet.

[0013] Furthermore, the waste heat recovery pipeline includes a main recovery pipe that directly leads the demineralized water to the deaerator, and a demineralized water inlet header and a demineralized water return header installed on the main recovery pipe. The demineralized water inlet header is connected to the coolant inlets of the fully enclosed sluice, the primary cooling device, and the first and second stage cooling devices of the conveying equipment for conveying demineralized water. The demineralized water return header is connected to the coolant outlets of the fully enclosed sluice, the primary cooling device, and the first and second stage cooling devices of the conveying equipment for recovering the demineralized water after heat exchange.

[0014] Furthermore, a second conveying device is provided between the crushing equipment and the dissolving device, and the processing system also includes a negative pressure dust removal device that is connected to the primary cooling device, the first and second conveying devices, the crushing equipment, and the second conveying device.

[0015] Preferably, the filtration and exhaust assembly includes a connecting box and an exhaust pipe. The inlet of the connecting box is located inside the dissolving device and is equipped with a grille for air intake filtration. The outlet of the connecting box is connected to the inlet of the exhaust pipe. The flushing assembly includes flushing pipes installed on both the connecting box and the grille.

[0016] Furthermore, the exhaust pipe and the connecting box are connected vertically, the grille is set on the side wall of the connecting box, and the bottom surface of the connecting box is inclined upward along the direction away from the grille, so as to return the rinsing water to the dissolving device.

[0017] Furthermore, when the connecting box is inclined upwards along the direction away from the grille, the angle between its bottom surface and the horizontal plane is 10°~20°.

[0018] Preferably, the fully enclosed chute includes a chute and a cover assembly, the chute and the cover assembly forming a sealed slag discharge channel with the upper end connected to the alkali recovery boiler and the lower end connected to the cooling device;

[0019] The casing assembly includes a first casing welded to the furnace wall of the alkali recovery boiler, a second casing disposed above the chute and connected to the first casing and the chute wall, and a third casing connected to the lower opening of the chute and the bottom of the second casing. The lower end of the third casing is provided with an expansion joint for absorbing vertical thermal expansion.

[0020] Furthermore, the second cover is a square shell shaped with its length direction horizontally arranged and a second inclined part at the bottom that is connected to the top of the chute wall. The front end of the second cover is connected to the first cover through a first connecting plate.

[0021] The third cover has a third inclined part at the front end that is connected to the outer wall of the chute lower opening, and a fourth horizontal part behind the third inclined part that is connected to the bottom of the second cover.

[0022] Furthermore, the fully enclosed chute is also equipped with an automatic coking removal device for cleaning coke buildup at the upper chute opening. The automatic coking removal device includes a coking removal cylinder, a pull rod, and a furnace-poke claw. The coking removal cylinder includes a base located outside the second cover, a sleeve fixedly installed at the front end of the base and extending into the second cover, and a telescopic end that is telescopically connected to the base inside the sleeve. The coking removal cylinder is connected to the rear outer wall of the second cover through the sleeve. The pull rod is located inside the second cover, with one end entering the sleeve and connecting to the telescopic end, and the other end of the pull rod connected to the furnace-poke claw.

[0023] Furthermore, the second housing has a viewing mirror on top and an observation door at the rear.

[0024] The beneficial effects of this utility model are:

[0025] (1) In the processing system of this utility model, the molten material first enters the cooling device for heat exchange, and after cooling, it enters the dissolving device to contact and dissolve with the dilute white liquid. Compared with the prior art where the high-temperature molten material directly contacts and cools with the dilute white liquid, the molten material cooling process of this utility model avoids the generation of a large amount of water vapor, reducing it by more than 90%, and there will be no noise pollution and safety hazards from the explosion of molten material and water.

[0026] (2) In the prior art, approximately 1 t / h of medium-temperature and medium-pressure steam is consumed for every 5 t / h of melt to disperse the melt. In the processing system of this utility model, the melt is cooled before entering the dissolution device, eliminating the need for high-temperature melt steam dispersion. Therefore, the steam dispersion device for the melt is eliminated, reducing energy consumption and lowering operating costs.

[0027] (3) In the processing system of this utility model, the cooling medium can be demineralized water. The waste heat recovery pipeline is connected to the fully enclosed chute and cooling device to introduce demineralized water to cool it. The demineralized water after absorbing the heat of the molten material returns to the main recovery pipe as makeup water for the deaerator of the alkali recovery boiler. This can reduce the steam consumption of the deaerator, recover the waste heat of the molten material (~3% of the total heat), and improve the energy utilization rate of the alkali recovery boiler.

[0028] (4) In the processing system of this utility model, the waste heat is recovered from the melt through the waste heat recovery pipeline, which reduces the heat brought into the dilute white liquid, effectively controls the temperature of the green liquid, and improves the efficiency of the subsequent causticizing process.

[0029] (5) In the processing system of this utility model, negative pressure dust removal equipment is used to remove dust from each piece of equipment, thereby avoiding dust on site and improving the quality of the surrounding environment.

[0030] (6) In the processing system of this utility model, a grid is set at the inlet of the connecting box on the dissolving device. When the gas passes through the grid, the dust and unvaporized liquid droplets in the gas are captured by the grid. The grid is used to purify the gas discharged through the dissolving tank, reduce the dust content of the discharged gas, and increase the dryness of the gas. A flushing pipe is set to regularly flush the connecting box and the grid of the exhaust pipe, reduce the risk of sodium salt caking and corrosion in the exhaust pipe, improve the continuous operation cycle of the system, and enhance the economic benefits of operation.

[0031] (7) In the processing system of this utility model, the cover assembly of the fully enclosed chute is formed by connecting the first cover, the second cover and the third cover. The first cover facilitates the connection of the upper end of the chute to the furnace wall of the alkali recovery boiler, the second cover facilitates the sealing of the upper part of the chute, and the third cover facilitates the sealing of the lower end of the chute to the cooling device. The cover assembly and the chute cooperate to form a sealed slag discharge channel, which avoids the blockage caused by the molten material accumulating and blocking when encountering cold air during the flow, as well as the production safety risks caused by the exposure of open flame.

[0032] (8) In the processing system of this utility model, the fully enclosed chute is equipped with an automatic descaling device, which can avoid the personal safety hazards caused by manual descaling.

[0033] (9) In the processing system of this utility model, the automatic coking device of the fully enclosed chute drives the furnace claw to clean the coking at the slag inlet through the coking cylinder. The telescopic end of the coking cylinder is set in the sleeve. The sleeve facilitates the installation of the coking cylinder at the rear end of the second cover and also facilitates the smooth movement of the pull rod along the sleeve axis, so as to achieve precise control of the furnace claw. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the processing system of this utility model.

[0035] Figure 2Flowchart of the processing method

[0036] Figure 3 Schematic diagram of a fully enclosed chute structure

[0037] Figure 4 for Figure 3 AA section diagram of the middle chute

[0038] Figure 5 Front view of the first casing

[0039] Figure 6 Left view of the first casing

[0040] Figure 7 Top view of the first casing

[0041] Figure 8 Front view of the second casing

[0042] Figure 9 Right view of the second casing

[0043] Figure 10 Front view of the third casing

[0044] Figure 11 Top view of the third casing

[0045] Figure 12 Schematic diagram of the automatic desiccant removal device

[0046] Figure 13 A partially enlarged schematic diagram of the automatic descorching device.

[0047] Figure 14 Front view of the exhaust assembly on the dissolving device

[0048] Figure 15 Top view of the exhaust assembly on the dissolving device

[0049] Figure 16 Side view of the venting and rinsing components on the dissolving device.

[0050] Among them: 1-Alkali recovery boiler 2-Fully enclosed chute 3-Primary cooling device 4-Conveying equipment I 5-Secondary cooling device 6-Crushing equipment 7-Conveying equipment II 8-Dissolving device (82-Exhaust pipe 83-Connecting box 84-Grate 85-Flushing pipe) 9-Negative pressure dust removal equipment 10-Deaerator 11-Automatic coke removal device 12-Demineralized water inlet header 13-Demineralized water return header 14-Main recovery pipe;

[0051] 110-Clearing cylinder (111-Base 112-Telescopic end 113-Sleeve) 120-Pull rod 130-Furnace claw 140-Sleeve mounting plate 150-Spring;

[0052] 200-Chute; 210-Mounting edge; 220-Flow guide; 230-Cooling chamber;

[0053] 311-First cover (311.1-First side plate 311.2-Comb-shaped top plate 311.3-First bottom plate 311.4-First mounting plate 311.5-Comb-shaped end plate) 312-Second cover 313-Observation door 314-Peeping mirror 315-Third cover 316-First connecting plate 317-Second inclined part 318-Third inclined part 319-Fourth horizontal part 320-Expansion joint. Detailed Implementation

[0054] The embodiments of this utility model are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0055] In the description of this utility model, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0056] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. Devices not detailed in this utility model are all commonly used devices in the art.

[0057] The following specific embodiments will provide a more detailed description of the present invention.

[0058] Example 1

[0059] like Figure 1As shown, this utility model provides a solid recovery and re-dissolution treatment system for molten material from an alkali recovery boiler, including a fully enclosed chute 2, a cooling device, a crushing device 6, and a dissolving device 8 arranged sequentially along the material flow direction. The fully enclosed chute 2 is equipped with an automatic coking device 11 for cleaning coking at the upper chute opening. It also includes a waste heat recovery pipeline for utilizing the demineralized water from the alkali recovery boiler 1. The waste heat recovery pipeline is connected to the fully enclosed chute 2 and the cooling device for introducing demineralized water to cool it.

[0060] The molten material generated by combustion in an alkali recovery boiler reaches temperatures as high as 800-900℃. It needs to be cooled to 50-200℃ by a cooling device. Based on the cooling capacity of existing equipment, the cooling device can be divided into multiple stages for cooling. In some preferred embodiments, the cooling device consists of two stages, including a primary cooling device 3 arranged along the material flow direction, a conveying device 4, and a secondary cooling device 5. The primary cooling device 3 first cools the molten material to 200-400℃, and then conveys it to the secondary cooling device 5 via the conveying device 4, where it is further cooled to 50-200℃.

[0061] The primary cooling device 3 includes a water-cooled shell and a stirring device arranged at the center of the water-cooled shell to achieve preliminary cooling. The conveying device 4 can be a water-cooled scraper conveyor. The secondary cooling device 5 can be a spiral cooler, which causes the molten material to move in a spiral motion inside, continuously transporting it from the inlet to the outlet. The fully enclosed chute 2, the primary cooling device 3, the conveying device 4, and the secondary cooling device 5 are all devices that introduce coolant (in this embodiment, demineralized water) for heat exchange, and therefore each has a coolant inlet and a coolant outlet.

[0062] The waste heat recovery pipeline includes a main recovery pipe 14 that directly leads the demineralized water to the deaerator 10, and a demineralized water inlet header 12 and a demineralized water return header 13 installed on the main recovery pipe 14. The demineralized water inlet header 12 is connected to the coolant inlets of the fully enclosed sluice 2, the primary cooling device 3, the conveying equipment 4, and the secondary cooling device 5 for conveying demineralized water. The demineralized water return header 13 is connected to the coolant outlets of the fully enclosed sluice 2, the primary cooling device 3, the conveying equipment 4, and the secondary cooling device 5 for recovering the demineralized water after heat exchange. The main recovery pipe 14 is used to draw out the demineralized water from the alkali recovery boiler 1. The demineralized water inlet header 12 and the demineralized water return header 13 are sequentially installed on the main recovery pipe 14 along the flow direction of the demineralized water. A valve can be installed on the demineralized water return header 13 to control the flow rate. The demineralized water inlet header 12 transports the demineralized water from the main recovery pipe 14 to the fully enclosed sluice 2, the primary cooling device 3, the conveying equipment 1 4, and the secondary cooling device 5. The demineralized water return header 13 is used to recover the demineralized water after heat exchange back to the main recovery pipe 14.

[0063] A second conveying device 7 is installed between the crushing device 6 and the dissolving device 8. The processing system also includes a negative pressure dust removal device 9, which is connected to the primary cooling device 3, the first conveying device 4, the secondary cooling device 5, the crushing device 6, and the second conveying device 7. The negative pressure dust removal device 9 collects the dust generated during the operation of the primary cooling device 3, the first conveying device 4, the secondary cooling device 5, the crushing device 6, and the second conveying device 7.

[0064] like Figure 3-13 As shown, the fully enclosed chute 2 includes a chute 200 and a cover assembly. The chute 200 and the cover assembly form a sealed slag discharge channel with its upper end connected to the alkali recovery boiler 1 and its lower end connected to the cooling device. The cover assembly includes a first cover 311 welded to the furnace wall of the alkali recovery boiler 1, a second cover 312 disposed above the chute 200 and connected to the first cover 311 and the chute 200 wall, and a third cover 315 connected to the lower opening of the chute 200 and the bottom of the second cover 312. The lower end of the third cover 315 is provided with an expansion joint 320 for absorbing vertical thermal expansion. The third cover 315 is connected to the primary cooling device 3 via the expansion joint 320.

[0065] The structure of the chute 200 is as follows Figure 4 As shown, the chute 200 is inclined at 45-50° relative to the horizontal plane. The top of the two side walls of the chute 200 extends outward to form mounting edges 210 for connection with the second cover 312. The bottom cross-section of the chute 200 is V-shaped and has a corresponding guide member 220. The guide member 220 is made of NiCr alloy material with weld overlay. The molten material flows downward at an angle through the surface of the guide member 220. A cooling chamber 230 is formed between the guide member 220 and the inner wall of the chute. The cooling chamber 230 is used to introduce coolant (in this embodiment, demineralized water) to cool the guide member 220, reducing the risk of damage to the guide member 220 due to excessively high temperature of the molten material. The coolant inlet of the fully enclosed chute 2 is located at the lower end of the chute 200, and the coolant outlet is located at the upper end of the chute 200, both of which are connected to the cooling chamber 230.

[0066] The first cover 311 structure is as follows: Figure 5-7 As shown, the first cover 311 includes a pair of parallel, L-shaped first side plates 311.1, a comb-shaped top plate 311.2 connecting the tops of the pair of first side plates 311.1, a first bottom plate 311.3 connecting the bottoms of the pair of first side plates 311.1, a first mounting plate 311.4 connecting the outer sides of the pair of first side plates 311.1, and a comb-shaped end plate 311.5 connecting the lower ends of the pair of first side plates 311.1. The comb-shaped top plate 311.2 is preferably a horizontal plate, and the comb-shaped end plate 311.5 is preferably a vertical plate. The top of the comb-shaped end plate 311.5 and the inner end of the comb-shaped top plate 311.2 are... Figure 5Both the middle and left ends are comb-shaped structures. The comb-shaped structure is designed to facilitate sealing and welding with the furnace wall with water-cooled pipes. The notches set at intervals on the comb-shaped structure correspond to the water-cooled pipes. After the first cover 311 is sealed and welded with the furnace wall, the interior is filled with high-temperature castable material GD170.

[0067] The structure of the second cover 312 is as follows: Figure 8-9 As shown, the second cover 312 is a square shell with its length horizontally arranged. The front end of the second cover 312 (with the end adjacent to the chute 200 as the front end) is connected to the first mounting plate 311.4 of the first cover 311 via the first connecting plate 316. The bottom of the second cover 312 is provided with a second inclined part 317 for corresponding connection with the top of the two side walls of the chute 200. The second inclined part 317 is a flange plate with the inclined direction corresponding to the chute 200. The second inclined part 317 is correspondingly connected to the mounting edge 210 of the chute 200 to seal the top of the chute 200.

[0068] The third enclosure 315 structure is as follows: Figure 10-11 As shown, the third cover 315 has a third inclined part 318 at the front end. The third inclined part 318 is a flange plate that is inclined from top to bottom toward the chute 200 and is connected to the outer surface of the chute wall on both sides of the lower opening of the chute 200. The third cover 315 has a fourth horizontal part 319 behind the third inclined part 318. The fourth horizontal part 319 is a horizontally arranged flange plate and is connected to the bottom of the second cover 312.

[0069] Automatic descorch clearing device 11 Figure 12-13 As shown, the system includes a coke-clearing cylinder 110, a pull rod 120, and a furnace-poke claw 130. The coke-clearing cylinder 110 includes a base 111 located outside the second cover 312, a sleeve 113 fixedly disposed at the front end of the base 111 (with the end near the chute 200 as the front end) and extending into the second cover 312, and a telescopic end 112 telescopically connected to the base 111 within the sleeve 113. The coke-clearing cylinder 110 is connected to the rear outer wall of the second cover 312 through the sleeve 113. The pull rod 120 is located inside the second cover 112, with one end entering the sleeve 113 and connecting to the telescopic end 112, and the other end of the pull rod 120 connected to the furnace-poke claw 130. The telescopic end 112 is coaxially disposed within the sleeve 113, and the inner diameter of the front end of the sleeve 113 and the outer diameter of the rear end of the pull rod 120 are aligned to ensure smooth axial movement of the pull rod 120 along the sleeve 113. The automatic coke removal device 11 drives the furnace claw 130 to clean the coke deposits on the upper slot through the coke removal cylinder 110. The telescopic end 112 of the coke removal cylinder 110 is set inside the sleeve 113. The sleeve 113 facilitates the installation of the coke removal cylinder 110 at the rear end of the second cover 312 and also facilitates the smooth movement of the pull rod 120 along the axial direction of the sleeve 113, so as to achieve precise control of the furnace claw 130.

[0070] In some preferred embodiments, the telescopic end 112 of the coke-clearing cylinder 110 extends and retracts horizontally, the pull rod 120 is horizontally set along the movement direction of the telescopic end 112, and multiple furnace-poke claws 120 can be set at intervals on the pull rod 120. In the initial state, the furnace-poke claws 120 are 300mm away from the upper opening of the chute 200.

[0071] In some preferred embodiments, a sleeve mounting plate 140 is provided on the surface of the sleeve 113. The sleeve mounting plate 140 is connected to the rear end face of the second cover 312 outside the second cover 312. A compression spring 150 is also provided between the sleeve mounting plate 140 and the second cover 312. The deformation direction of the compression spring 150 is consistent with the movement direction of the telescopic end 112. When the telescopic end 112 of the coke cleaning cylinder 110 moves, the compression spring 150 can buffer the coke cleaning cylinder 110, avoid damage to the mounting point, and improve the operational reliability of the automatic coke cleaning device 11.

[0072] In some preferred embodiments, the second housing 312 is provided with a viewing mirror 314 at the top and an observation door 313 at the rear end, so as to facilitate observation of the working status of the chute 200 and the automatic desiccant device 11.

[0073] The working principle of the fully enclosed chute 2 is as follows: molten material enters the chute 200 from the upper opening, flows downwards at an angle through the surface of the guide member 220, and the cover assembly formed by the first cover 311, the second cover 312, and the third cover 315 keeps the molten material in a sealed environment before flowing into the primary cooling device 3. During the flow of the molten material, the automatic coking device 11 drives the furnace claw 130 through the coking cylinder 110 to clean the coke deposits at the upper opening of the chute 200.

[0074] To address the shortcomings of existing dissolving tanks that directly discharge dust-laden gas, accelerating pipe blockage and corrosion and affecting normal equipment operation, this embodiment improves the dissolving device 8 (i.e., the dissolving tank), such as... Figure 14-16 As shown, a filtration and exhaust assembly and a rinsing assembly for rinsing the filtration and exhaust assembly are provided on the dissolving device 8. The filtration and exhaust assembly includes a connecting box 83 and an exhaust pipe 82. The inlet of the connecting box 83 is located inside the dissolving device 8 and a grille 84 is provided at the inlet for air filtration. The outlet of the connecting box 83 is connected to the inlet of the exhaust pipe 82. The rinsing assembly includes rinsing pipes 85 provided on both the connecting box 83 and the grille 84.

[0075] The exhaust pipe 82 and the connecting box 83 are connected vertically. The grille 84 is located on the side wall of the connecting box 83, and the bottom surface of the connecting box 83 is located away from the grille 84. Figure 16The connecting box 83 is inclined upwards (towards the left) to allow rinsing water to flow back into the dissolving device 8. In some preferred embodiments, when the connecting box 83 is inclined upwards away from the grid 84, the angle between its bottom surface and the horizontal plane is 10° to 20°. This facilitates the return of condensate and rinsing water in the connecting box 83 to the dissolving device 8 after passing through the grid 84.

[0076] In a preferred embodiment, the dissolving device 8 has an opening at the top, and the exhaust pipe 82 is connected to the opening at the bottom and above the dissolving device 8. The connecting box 83 is located below the opening and connected to the opening at the top. The connecting box 83 is generally rectangular, and a grille 84 is provided on one side of the cuboid. The grille 84 can be used as one side of the cuboid. The grille 84 has a mesh structure and is made of corrosion-resistant stainless steel. The grille 84 is installed at the inlet of the connecting box 83. Dust and unvaporized liquid droplets in the gas are captured by the grille 84 to separate the gas into vapor and water, improve the dryness of the gas, and simultaneously capture dust carried in the gas to pre-filter and purify the gas entering the exhaust pipe 82.

[0077] The flushing pipes 5 can be installed on the four sides of the cuboid connecting box 83, excluding the top and bottom surfaces. In a preferred embodiment, four flushing pipes 85 can be installed, one of which is installed on the outside of the grille 84. Figure 16 The top of the right side of the cuboid facilitates the cleaning of filter deposits; the other three flushing pipes 85 are respectively located at the top of the other three sides inside the cuboid. The flushing pipes 85 are used to flush the connecting box 83 and the grid 84 after the exhaust structure of the alkali recovery boiler dissolving tank has been running for a period of time, to remove the deposits in the connecting box 83 and the grid 84, including but not limited to salt particles or plate-shaped salt blocks.

[0078] The inlet of the flushing pipe 85 is connected to an external water source. In a preferred embodiment, it can be connected to the circulating water pipe of the dissolving device 8, using the circulating water of the dissolving device 8 as a water source to flush the filter exhaust assembly. In a preferred embodiment, a valve can be installed on the pipe connecting the flushing pipe 85 to the external water source to control the valve to periodically flush the grille 84 and the connecting box 83, ensuring the unobstructed flow of the grille 84 and the connecting box 83, which is conducive to the long-term stable exhaust of the dissolving device 8.

[0079] The working principle of the dissolving device 8 is as follows: when solid salt enters the dissolving device and reacts with dilute white liquid to dissolve, gas is generated. The gas, carrying dust (sodium salt) and water vapor, passes through the grid 84 and enters the connecting box 83, then through the exhaust pipe 82 to connect to the subsequent process system for heat energy recovery. When the gas passes through the grid 84, dust and unvaporized liquid droplets in the gas are captured. The grid 84 purifies the gas discharged from the dissolving device, reducing the dust content and increasing the dryness of the gas, thus reducing sodium salt caking, blockage, and corrosion in the exhaust pipe and subsequent process system. At the same time, the connecting box 83 and the grid 84 are periodically flushed through the flushing pipe 85, especially the grid 84, which should be flushed at shorter intervals. This reduces sodium salt caking, blockage, and corrosion in the exhaust pipe and subsequent process system, providing a guarantee for the long-term stable operation of the entire alkali recovery system and improving the economic efficiency of operation.

[0080] Example 2

[0081] like Figure 2 As shown, this embodiment provides a method for solid-state recovery and redissolution of molten material from an alkali recovery boiler, implemented using the aforementioned solid-state recovery and redissolution system for molten material from an alkali recovery boiler, including:

[0082] S1. The molten material generated by the combustion of the alkali recovery boiler 1 at 800~900℃ is led out through the fully enclosed chute 2 to the inlet of the primary cooling device 3. It enters the primary cooling device 3 and is cooled to 200~400℃ to form solid salt. Then it is conveyed through the conveying equipment 4 to enter the secondary cooling device 5 for further cooling to 50~200℃ to obtain solid salt.

[0083] S2. The cooled solid salt enters the crushing device 6 and is crushed to obtain fine solid salt particles with a particle size of less than 1 mm. The fine solid salt particles are conveyed to the dissolving device 8 by the conveying device 7 to react and dissolve with the dilute white liquid to form green liquid.

[0084] The molten material at 800~900℃ is first cooled to 50~200℃ before being crushed and dissolved. Compared with the existing technology where the molten material vapor is dispersed and then directly contacts the dilute white liquid, the cooling device of this utility model uses demineralized water for indirect heat exchange cooling. The cooling process no longer generates a large amount of water vapor, thus avoiding noise pollution and safety hazards.

[0085] In the above process, the molten material chute 2, primary cooler 3, conveying equipment 1 4, and secondary cooling equipment 5 all adopt indirect cooling with demineralized water. The demineralized water is sent to the above four cooling devices for heat exchange through the demineralized water inlet header 12. The demineralized water after heat exchange is collected and sent to the deaerator 10 through the demineralized water return header 13. This can increase the temperature of the demineralized water entering the deaerator 10 and reduce the steam consumption required for deoxygenation. Online instruments such as flow rate and temperature can be installed on the demineralized water inlet header 12 and / or the demineralized water return header 13 to monitor the entire cooling water system in real time and ensure system stability.

[0086] During the above process, the negative pressure dust removal equipment 9 is started to collect the dust generated during the operation of the primary cooling device 3, conveying device 1 4, secondary cooling device 5, crushing device 6, and conveying device 2 7. The primary cooling device 3, conveying device 1 4, secondary cooling device 5, crushing device 6, and conveying device 2 7 are all operating under negative pressure to avoid dust on site.

[0087] During the above process, the automatic coking removal device 11 configured in the fully enclosed chute 2 can be set to periodically clean the coking at the top of the chute, or it can be cleaned remotely by the operator.

[0088] In the processing of this utility model, demineralized water is used as a cooling medium. After absorbing the heat of the molten material, the demineralized water is used as makeup water for the deaerator of the alkali recovery boiler. This can reduce the steam consumption of the deaerator, recover the waste heat of the molten material, and improve the energy utilization rate of the alkali recovery boiler.

Claims

1. A solid-state recovery and redissolution treatment system for molten material from an alkali recovery boiler, characterized in that, It includes a fully enclosed chute (2), a cooling device, a crushing device (6) and a dissolving device (8) arranged sequentially along the material flow direction. The dissolving device (8) is equipped with a filter exhaust assembly and a flushing assembly that can flush the filter exhaust assembly. It also includes a waste heat recovery pipeline for utilizing the demineralized water from the alkali recovery boiler (1), wherein the waste heat recovery pipeline is connected to a fully enclosed chute (2) and a cooling device for introducing demineralized water for cooling.

2. The solid-state recovery and redissolution treatment system for alkali recovery boiler molten material as described in claim 1, characterized in that, The cooling device includes a primary cooling device (3), a conveying device (4), and a secondary cooling device (5) arranged along the material flow direction. Each of the fully enclosed chute (2), the primary cooling device (3), the conveying device (4), and the secondary cooling device (5) is provided with a coolant inlet and a coolant outlet.

3. The solid-state recovery and redissolution treatment system for alkali recovery boiler molten material as described in claim 2, characterized in that, The waste heat recovery pipeline includes a main recovery pipe (14) that directly leads the demineralized water to the deaerator (10), and a demineralized water inlet header (12) and a demineralized water return header (13) installed on the main recovery pipe (14). The demineralized water inlet header (12) is connected to the coolant inlet of the fully enclosed sluice (2), the primary cooling device (3), the first conveying device (4), and the secondary cooling device (5) for conveying demineralized water. The demineralized water return header (13) is connected to the coolant outlet of the fully enclosed sluice (2), the primary cooling device (3), the first conveying device (4), and the secondary cooling device (5) for recovering the demineralized water after heat exchange.

4. The solid-state recovery and redissolution treatment system for alkali recovery boiler molten material as described in claim 2, characterized in that, The crushing device (6) and the dissolving device (8) are connected by a second conveying device (7). The processing system also includes a negative pressure dust removal device (9) that is connected to the first-level cooling device (3), the first conveying device (4), the second-level cooling device (5), the crushing device (6), and the second conveying device (7).

5. The solid-state recovery and redissolution treatment system for alkali recovery boiler molten material as described in claim 1, characterized in that, The filter exhaust assembly includes a connecting box (83) and an exhaust pipe (82). The inlet of the connecting box (83) is located inside the dissolving device (8) and a grille (84) is provided at the inlet for air intake filtration. The outlet of the connecting box (83) is connected to the inlet of the exhaust pipe (82). The flushing assembly includes flushing pipes (85) provided on both the connecting box (83) and the grille (84).

6. The solid-state recovery and redissolution treatment system for alkali recovery boiler molten material as described in claim 5, characterized in that, The exhaust pipe (82) and the connecting box (83) are connected vertically. The grille (84) is set on the side wall of the connecting box (83). The bottom surface of the connecting box (83) is inclined upward along the direction away from the grille (84) to return the rinsing water to the dissolving device (8).

7. The solid-state recovery and redissolution treatment system for alkali recovery boiler molten material as described in claim 6, characterized in that, When the connecting box (83) is inclined upward in the direction away from the grid (84), the angle between the bottom surface and the horizontal plane is 10°~20°.

8. The solid-state recovery and redissolution treatment system for alkali recovery boiler molten material as described in claim 1, characterized in that, The fully enclosed chute (2) includes a chute (200) and a cover assembly. The chute (200) and the cover assembly form a sealed slag discharge channel with the upper end connected to the alkali recovery boiler (1) and the lower end connected to the cooling device. The casing assembly includes a first casing (311) welded to the furnace wall of the alkali recovery boiler (1), a second casing (312) disposed above the chute (200) and connected to the first casing (311) and the chute (200) wall, and a third casing (315) connected to the lower opening of the chute (200) and the bottom of the second casing (312). The lower end of the third casing (315) is provided with an expansion joint (320) for absorbing vertical thermal expansion.

9. The solid-state recovery and redissolution treatment system for alkali recovery boiler molten material as described in claim 8, characterized in that, The second cover (312) is a square shell with its length direction horizontally arranged and a second inclined part (317) is provided at the bottom, which is correspondingly connected to the top of the chute wall (200). The front end of the second cover (312) is correspondingly connected to the first cover (311) through the first connecting plate (316). The third cover (315) has a third inclined part (318) at the front end, which is connected to the outer wall of the lower groove of the chute (200). The third cover (315) has a fourth horizontal part (319) behind the third inclined part (318), which is connected to the bottom of the second cover (312).

10. The solid-state recovery and redissolution treatment system for alkali recovery boiler molten material as described in claim 9, characterized in that, The fully enclosed chute (2) is also equipped with an automatic coking device (11) for cleaning the coking at the upper chute opening. The automatic coking device (11) includes a coking cylinder (110), a pull rod (120), and a furnace-poke claw (130). The coking cylinder (110) includes a base (111) located outside the second cover (312), a sleeve (113) fixedly installed at the front end of the base (111) and extending into the second cover (312), and a telescopic end (112) telescopically connected to the base (111) inside the sleeve (113). The coking cylinder (110) is connected to the rear outer wall of the second cover (312) through the sleeve (113). The pull rod (120) is located inside the second cover (112), with one end entering the sleeve (113) and connected to the telescopic end (112). The other end of the pull rod (120) is connected to the furnace-poke claw (130).

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