Treatment system and treatment method for solid recovery and redissolution of melt in alkali recovery boiler

Abstract

The invention discloses a treatment system and a treatment method for solid recovery and redissolution of melt in an alkali recovery boiler, and relates to the technical field of alkali recovery boilers. The treatment system comprises a fully-closed chute, a cooling device, crushing equipment and a dissolving device which are sequentially arranged in the material flow direction, wherein an automatic coke cleaning device is arranged on the fully-closed chute and used for cleaning coke in an upper notch; the waste heat recovery pipeline is used for utilizing desalted water of the alkali recovery boiler; and the waste heat recovery pipeline is communicated with the fully-closed chute and the cooling device and is used for introducing the desalted water to cool the desalted water. In the treatment system, the melt firstly enters the cooling device for heat exchange and then enters the dissolving device for contact dissolution with the dilute white liquid after being cooled, compared with the prior art that the high-temperature melt is directly contacted with the dilute white liquid for cooling, a large amount of water vapor is not generated in the cooling process of the melt, and the water vapor is reduced by 90% or above; and noise pollution and potential safety hazards caused by melt-water explosion are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of alkali recovery boilers, and in particular to a processing system and method for solid-state recovery and redissolution of melts in alkali recovery boilers. Background Art

[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 combustion in the alkali recovery boiler (abbreviated as "alkali boiler", also known as "black liquor boiler") enters the dissolution tank through the melt chute at the bottom of the furnace and is directly mixed with the dilute white liquor, where it is cooled and dissolved. The resulting green liquor enters the causticizing section, and the alkali liquor generated after causticizing returns to the pulping production system.

[0003] Patent CN202211689219.8 discloses an automatic coking system for alkali furnace chutes, comprising a servo horizontal movement assembly installed at the front end of several chutes at the bottom of the alkali furnace, a servo automatic coking assembly installed below the servo automatic coking assembly, and a coking tool installed on the servo automatic coking assembly. The disadvantage of this patent is that the servo horizontal movement of the coking assembly targets a single coking location in the chute and cannot cope with the variable coking conditions on site. Moreover, the chute and the coking assembly are both open and cannot be completely sealed. Sometimes they are affected by cold air, causing cooling and agglomeration, which affects the continuous flow of the melt and can also expose open flames and affect safety.

[0004] Patent CN201110001768.7 shows that when explosions occur continuously, they will cause great damage to the dissolving tank and the agitator in the tank, and the tank leaks, agitator blades fall off, and seal leaks often occur. At the same time, after a long period of operation, large crystals of scale on the chute inlet and the walls will fall and damage the agitator. Moreover, once one of them is damaged and cannot be used, it will cause uneven mixing of the entire dissolving tank, affecting the quality of the green liquor and making explosions more likely to occur. The alkali recovery boiler dissolving tank of the patent includes a tank body and several agitating devices, and is characterized in that the cross section of the tank body is 8-shaped. The patent has the following disadvantages: (1) the high-temperature melt is directly cooled in contact with the dilute white liquor, which poses an explosion risk; (2) the sensible heat of the high-temperature melt is not recycled; (3) the amount of water vapor generated during the cooling of the high-temperature melt is huge; (4) the temperature of the green liquor is difficult to accurately control.

[0005] Patent CN201210125397.8 cools the desalinated cooling water in the alkali recovery boiler chute. Qualified desalinated cooling water is then delivered to the boiler to replenish preheat water. Unqualified desalinated cooling water is recovered or treated for discharge. This patent has the disadvantage of only recovering a small portion of the sensible heat from the melt, with the majority entering the green liquor and failing to enter the alkali recovery boiler system to improve energy efficiency.

[0006] Patent CN202410951628.3 describes an alkali furnace waste gas treatment system and method, including a dissolving tank, a mixing tank, a smelting chute for the alkali furnace, a gas collecting hood, a first scrubber, and a second scrubber. This patent has the following disadvantages: (1) the system is very complex; (2) the collected waste gas contains a high dust content, which can easily cause equipment clogging.

[0007] In summary, the above-mentioned traditional processes and improved technologies still have the following problems and shortcomings: (1) Safety hazards: The high-temperature molten material must be dispersed before reaching the green liquor surface in the dissolving tank. Otherwise, the molten material and water will explode when in contact. In severe cases, the dissolving tank may rupture and even cause personal injury. (2) Steam consumption: In order to safely break up the molten material and reduce the explosion caused by the dissolution of the molten material, sufficient steam will be used, which also leads to steam consumption and increased operating costs; (3) Water vapor emission problem: The high-temperature molten material is in direct contact with the dilute white liquor. The entire dissolution process generates a large amount of high-temperature water vapor. An open discharge port is required. The steam escape causes thermal pollution, and the noise level at the discharge port is as high as 90dB or more, resulting in serious noise pollution and a series of ash blockage caused by water vapor collection, which affects operation. (4) Heat energy waste: The temperature of the melt is as high as 800-900℃. Direct cooling causes a large amount of high-temperature waste heat to be absorbed by the dilute white liquor, part of which is converted into water vapor and discharged, resulting in a decrease in the energy recovery rate of the alkali recovery boiler system; (5) Fluctuation in green liquor quality: The green liquor temperature is difficult to accurately control in the direct cooling process, which can easily cause the green liquor temperature to exceed the process requirements (usually ≤80°C), affecting the efficiency of the subsequent causticizing process.

[0008] Therefore, a treatment system and method for solid-state recovery and redissolution of alkali recovery boiler melt is needed. This system eliminates the need for steam dispersion of the melt, avoids the noise pollution and safety hazards of melt-water explosions, and eliminates the generation of large amounts of water vapor during the cooling process. The entire process operates within a closed negative pressure system, eliminating the leakage of dust, smoke, and water vapor. Furthermore, the heat released during this process is fully recovered, reducing the heat introduced into the dilute white liquor. This system effectively controls the green liquor temperature and improves the efficiency of the subsequent causticizing process. Summary of the Invention

[0009] The present invention aims to address the shortcomings of the aforementioned background technology by providing a system and method for solid-state recovery and redissolution of molten material from an alkali recovery boiler. This system eliminates the need for steam dispersion of the molten material, avoids the noise pollution and safety hazards of molten-water explosions, and eliminates the generation of large amounts of water vapor during the cooling process. The entire process operates within a sealed negative pressure system, eliminating the leakage of dust, smoke, and water vapor. Furthermore, the system fully recovers the heat released during this process, reducing heat carried over into the dilute white liquor. This system effectively controls the temperature of the green liquor and improves the efficiency of the subsequent causticizing step.

[0010] The technical solution of the present invention is: a processing system for solid-state recovery and re-dissolution of molten material from an alkali recovery boiler, characterized by comprising a fully enclosed chute, a cooling device, a crushing device, and a dissolving device arranged in sequence along the material flow direction; the fully enclosed chute is provided with an automatic coke cleaning device for cleaning coke from the upper notch; It also includes a waste heat recovery pipeline for utilizing the desalted water of the alkali recovery boiler. The waste heat recovery pipeline is connected to the fully enclosed chute and the cooling device for introducing desalted water to cool it.

[0011] Preferably, the cooling device includes a primary cooling device, a conveying equipment primary and a secondary cooling device arranged along the material flow direction, and the fully enclosed chute, the primary cooling device, the conveying equipment primary and the secondary cooling device are respectively provided with a coolant inlet and a coolant outlet.

[0012] Furthermore, the waste heat recovery pipeline includes a main recovery pipe that directly connects the desalted water to the deaerator, and a desalted water inlet main pipe and a desalted water return main pipe arranged on the main recovery pipe. The desalted water inlet main pipe is connected to the cooling liquid inlet of the fully enclosed chute, the first-level cooling device, the first and second-level cooling devices of the conveying equipment for conveying desalted water, and the desalted water return main pipe is connected to the cooling liquid outlet of the fully enclosed chute, the first-level cooling device, the first and second-level cooling devices of the conveying equipment for recovering the desalted water after heat exchange.

[0013] Furthermore, a second conveying device is provided between the crushing device and the dissolving device, and the processing system also includes a negative pressure dust removal device connected to the primary cooling device, the first and second cooling devices of the conveying device, the crushing device, and the second conveying device.

[0014] Preferably, the fully enclosed chute includes a chute and a cover assembly, wherein the chute and the cover assembly form a sealed slag discharge channel whose upper end is connected to the alkali recovery boiler and whose lower end is connected to the cooling device; The cover assembly includes a first cover welded to the furnace wall of the alkali recovery boiler, a second cover arranged above the chute and connected to the first cover and the chute wall, and a third cover connected to the lower notch of the chute and the bottom of the second cover. The lower end of the third cover is provided with an expansion joint for absorbing vertical thermal expansion.

[0015] Furthermore, the second cover is in the shape of a square shell with its length arranged horizontally and a second inclined portion provided at the bottom thereof to be connected to the top of the chute wall. The front end of the second cover is connected to the first cover via a first connecting plate. The front end of the third cover shell is provided with a third inclined portion correspondingly connected to the outer wall of the lower slot of the chute, and the third cover shell is provided with a fourth horizontal portion behind the third inclined portion connected to the bottom of the second cover shell.

[0016] Furthermore, the automatic coke cleaning device includes a coke cleaning cylinder, a pull rod and a furnace-poking claw. The coke cleaning cylinder includes a base located outside the second cover shell, a sleeve fixedly arranged at the front end of the base and extending into the second cover shell, and a telescopic end telescopically connected to the base in the sleeve. The coke cleaning cylinder is connected to the outer wall of the rear end of the second cover shell through the sleeve. The pull rod is located in the second cover shell and one end of the pull rod enters the sleeve and is connected to the telescopic end. The other end of the pull rod is connected to the furnace-poking claw.

[0017] The present invention also provides a treatment method for any of the above-mentioned alkali recovery boiler melt solid recovery and redissolution treatment systems, comprising: S1. The 800-900℃ molten material generated by combustion in the alkali recovery boiler is drawn out through a fully enclosed chute and then cooled to 50-200℃ by a cooling device to obtain solid salt; S2. The cooled solid salt enters the crushing equipment for crushing to obtain solid salt fine particles. The solid salt fine particles are transported to the dissolving device to react and dissolve with the dilute white liquor to form green liquor.

[0018] Preferably, in step S1, after the 800-900°C melt is drawn out through a fully enclosed chute, it first enters a primary cooling device to be cooled to 200-400°C, and then enters a secondary cooling device to be further cooled to 50-200°C to obtain solid salt.

[0019] Preferably, in step S2, the crushing process is performed to obtain solid salt fine particles with a particle size of less than 1 mm.

[0020] The beneficial effects of the present invention are: (1) In the processing system of the present invention, the fully enclosed chute is equipped with an automatic coke cleaning device, which can avoid the personal safety hazards caused by manual coke cleaning.

[0021] (2) In the processing system of the present invention, the molten material first enters the cooling device for heat exchange, and then enters the dissolving device after cooling to dissolve in contact with the dilute white liquor. Compared with the prior art in which the high-temperature molten material is directly cooled in contact with the dilute white liquor, the molten material cooling process of the present invention avoids the generation of a large amount of water vapor, reducing it by more than 90%, and also avoids the noise pollution and safety hazards of the molten material-water explosion.

[0022] (3) In the prior art, about 1 t / h of medium-temperature and medium-pressure steam is consumed for every 5 t / h of melt produced to disperse the melt. In the processing system of the present invention, the melt is cooled before entering the dissolving device, and there is no need to disperse the high-temperature melt with steam. Therefore, the steam dispersion device for the melt is eliminated, which reduces energy consumption and lowers operating costs.

[0023] (4) In the treatment system of the present invention, desalted water can be used as the cooling medium. The waste heat recovery pipeline is connected to the fully enclosed chute and the cooling device to pass desalted water to cool it. The desalted water, after absorbing the heat of the melt, returns to the main recovery pipe and serves as the feed water for the deaerator of the alkali recovery boiler. This can reduce the steam consumption of the deaerator, recover the waste heat of the melt (~3% of the total heat), and improve the energy utilization rate of the alkali recovery boiler.

[0024] (5) In the treatment system of the present invention, waste heat is recovered from the melt through the waste heat recovery pipeline, which reduces the heat brought into the dilute white liquor, effectively controls the temperature of the green liquor, and improves the efficiency of the subsequent causticizing process.

[0025] (6) In the treatment system of the present invention, negative pressure dust removal equipment is used to perform negative pressure dust removal on each device to avoid on-site dust and improve the quality of the surrounding environment.

[0026] (7) In the processing system of the present invention, the cover assembly 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 with 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 cooperates with the chute to form a sealed slag discharge channel, thereby avoiding the agglomeration and blockage of the molten material by the cold wind during the flow process, and the production safety risks caused by the exposure of open flames.

[0027] (8) In the processing system of the present invention, the automatic coke cleaning device drives the furnace-poking claw to clean the coke at the slag inlet through the coke cleaning cylinder. The telescopic end of the coke cleaning cylinder is arranged in the sleeve. The sleeve is convenient for the installation of the coke cleaning cylinder at the rear end of the second cover shell and for limiting the smooth movement of the pull rod along the axial direction of the sleeve, thereby realizing precise control of the furnace-poking claw.

[0028] (9) In the treatment method of the present invention, the 800-900°C melt is first cooled to 50-200°C and then crushed and dissolved. Compared with the prior art in which the melt vapor is dispersed and then directly contacts the dilute white liquor, the cooling device of the present invention uses desalted water for inter-wall heat exchange cooling. The cooling process no longer generates a large amount of water vapor, thereby avoiding noise pollution and safety hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 Schematic diagram of the processing system of the present invention Figure 2 Flow chart of the processing method of the present invention Figure 3Schematic diagram of the fully enclosed chute structure Figure 4 for Figure 3 AA section of the middle chute Figure 5 Main view of the first cover Figure 6 Left view of the first cover Figure 7 A top view of the first cover Figure 8 Main view of the second cover Figure 9 Right view of the second cover Figure 10 Main view of the third cover Figure 11 Top view of the third cover Figure 12 Schematic diagram of the automatic defocusing device Figure 13 A partially enlarged schematic diagram of the automatic defocusing device Figure 14 Top view of a spiral cooler used to cool boiler melt Figure 15 Schematic diagram of the shaft structure Figure 16 Schematic diagram of the structure with a cold chamber unit in the shell Figure 17 Schematic diagram of the cross section of the shell Among them: 1- alkali recovery boiler 2- fully enclosed chute 3- primary cooling device 4- conveying equipment 1 5- secondary cooling device 6- crushing equipment 7- conveying equipment 2 8- dissolving device 9- negative pressure dust removal equipment 10- deaerator 11- automatic coke cleaning device 12- desalted water inlet main pipe 13- desalted water return main pipe 14- main recovery pipe; 110 - coke cleaning cylinder (111 - base 112 - telescopic end 113 - sleeve) 120 - pull rod 130 - furnace claw 140 - sleeve mounting plate 150 - spring; 200 - chute 210 - mounting edge 220 - flow guide 230 - cooling chamber; 311 - First housing (311.1 - First side panel 311.2 - Comb-shaped top panel 311.3 - First bottom panel 311.4 - First mounting panel 311.5 - Comb-shaped end panel) 312 - Second housing 313 - Observation door 314 - Sight glass 315 - Third housing 316 - First connecting plate 317 - Second inclined portion 318 - Third inclined portion 319 - Fourth horizontal portion 320 - Expansion joint; 100 - Spiral cooler for cooling boiler melt (101 - housing 102 - rotating shaft 103 - water inlet core pipe 104 - rotary joint 105 - feed port 106 - cover plate 107 - partition plate 108 - cold chamber unit 121 - reflux chamber 122 - first spiral blade 123 - paddle blade 124 - second spiral blade 125 - gear 141 - water inlet 142 - water outlet). DETAILED DESCRIPTION

[0030] The embodiments of the present invention are described in detail below, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but are not to be construed as limiting the present invention.

[0031] In the description of the present invention, it should be understood that the terms "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0032] 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 the technical features being referred to. Thus, features specified as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined. Any devices not described in detail herein are commonly used in the art.

[0033] The following specific examples further illustrate the present invention in detail.

[0034] Example 1 like Figure 1 As shown, the present invention provides a processing system for solid-state recovery and redissolution of melt from an alkali recovery boiler, comprising a fully enclosed chute 2, a cooling device, a crushing device 6, and a dissolving device 8 arranged in sequence along the material flow direction. The fully enclosed chute 2 is provided with an automatic coke cleaning device 11 for cleaning coke from the upper notch; the system also comprises a waste heat recovery pipeline for utilizing desalted water from the alkali recovery boiler 1, the waste heat recovery pipeline being connected to the fully enclosed chute 2 and the cooling device for introducing desalted water for cooling.

[0035] The molten material produced by combustion in the alkali recovery boiler reaches a temperature of 800-900°C and needs to be cooled to 50-200°C via 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 is divided into two stages, including a primary cooling device 3, a conveying device 4, and a secondary cooling device 5 arranged along the material flow. The primary cooling device 3 first cools the molten material to 200-400°C, then conveys it to the secondary cooling device 5 via the conveying device 4, where it is further cooled to 50-200°C.

[0036] The primary cooling device 3 comprises a water-cooled housing and a stirring device positioned at its center, providing initial cooling. The conveying device 4 can be a water-cooled scraper conveyor. The secondary cooling device 5 can be a spiral cooler, inducing a spiral motion within the melt, continuously transporting it from the feed inlet to the discharge outlet. The fully enclosed chute 2, primary cooling device 3, conveying device 4, and secondary cooling device 5 all operate by introducing a coolant (desalted water in this embodiment) for heat exchange, and therefore each has a coolant inlet and outlet.

[0037] The waste heat recovery pipeline includes a main recovery pipe 14 that directly directs desalted water to the deaerator 10, as well as a desalted water inlet main pipe 12 and a desalted water return main pipe 13 installed on the main recovery pipe 14. The desalted water inlet main pipe 12 is connected to the coolant inlets of the fully enclosed chute 2, the primary cooling device 3, the conveying device 14, and the secondary cooling device 5 for conveying desalted water. The desalted water return main pipe 13 is connected to the coolant outlets of the fully enclosed chute 2, the primary cooling device 3, the conveying device 14, and the secondary cooling device 5 for recovering the desalted water after heat exchange. The main recovery pipe 14 is used to draw desalted water from the alkali recovery boiler 1. The desalted water inlet main pipe 12 and the desalted water return main pipe 13 are installed on the main recovery pipe 14 in sequence along the flow direction of the desalted water. A valve can be installed on the desalted water return main pipe 13 to control the flow rate. The desalted water inlet main pipe 12 transports the desalted water on the main recovery pipe 14 to the fully enclosed chute 2, the primary cooling device 3, the conveying equipment 1 4, and the secondary cooling device 5. The desalted water return main pipe 13 is used to recover the desalted water after heat exchange to the main recovery pipe 14.

[0038] A conveying device 2 7 is installed between the crushing device 6 and the dissolving device 8. The treatment system also includes a negative pressure dust removal device 9 connected to the primary cooling device 3, conveying device 1 4, secondary cooling device 5, crushing device 6, and conveying device 2 7. The negative pressure dust removal device 9 collects 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.

[0039] like Figure 3-13As 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 whose upper end is connected to the alkali recovery boiler 1 and the lower end is 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 arranged above the chute 200 and connected to the first cover 311 and the trough wall of the chute 200, and a third cover 315 connected to the lower notch 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 pipeline of the primary cooling device 3 through the expansion joint 320.

[0040] The structure of chute 200 is as follows: Figure 4 As shown, the chute 200 is tilted 45-50 degrees relative to the horizontal plane. The tops of the two side walls of the chute 200 extend outward to form mounting edges 210 for connection to the second housing 312. The bottom cross-section of the chute 200 is V-shaped and equipped with a correspondingly shaped flow guide 220. The flow guide 220 is made of a welded NiCr alloy. The molten material flows downward along the surface of the flow guide 220. A cooling chamber 230 is formed between the flow guide 220 and the inner wall of the chute. The cooling chamber 230 is used to pass a coolant (desalted water in this embodiment) to cool the flow guide 220 and reduce the risk of damage to the flow guide 220 due to excessive molten temperature. The coolant inlet of the fully enclosed chute 200 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.

[0041] The structure of the first housing 311 is as follows Figure 5-7 As shown, the first housing 311 includes a pair of parallel, L-shaped first side panels 311.1, a comb-shaped top panel 311.2 connecting the tops of the pair of first side panels 311.1, a first bottom panel 311.3 connecting the bottoms of the pair of first side panels 311.1, a first mounting panel 311.4 connecting the outer sides of the pair of first side panels 311.1, and a comb-shaped end panel 311.5 connecting the lower ends of the pair of first side panels 311.1. The comb-shaped top panel 311.2 is preferably a horizontal panel, and the comb-shaped end panel 311.5 is preferably a vertical panel. The top of the comb-shaped end panel 311.5 and the inner end of the comb-shaped top panel 311.2 ( Figure 5 The comb-shaped structure is provided to facilitate sealing and welding with the furnace wall provided with water-cooling pipes. The gaps arranged at intervals on the comb-shaped structure just correspond to the water-cooling pipes. After the first cover shell 311 is sealed and welded to the furnace wall, high-temperature castable GD170 is poured inside.

[0042] The second housing 312 has a structure as follows Figure 8-9As shown, it is a square shell-shaped shell arranged horizontally in the longitudinal direction. The front end of the second cover shell 312 (the end adjacent to the chute 200 is the front end) is connected to the first mounting plate 311.4 of the first cover shell 311 through the first connecting plate 316. The bottom of the second cover shell 312 is provided with a second inclined portion 317 for corresponding connection with the top of the trough wall on both sides of the chute 200. The second inclined portion 317 is a flange plate corresponding to the inclined direction of the chute 200. The second inclined portion 317 is connected to the mounting edge 210 of the chute 200 for sealing the top of the chute 200.

[0043] The third housing 315 has a structure as follows Figure 10-11 As shown, the third cover shell 315 has a third inclined portion 318 at the front end, and the third inclined portion 318 is a flange plate inclined from top to bottom toward the chute 200, and is correspondingly connected to the outer surfaces of the groove walls on both sides of the lower groove opening of the chute 200. The third cover shell 315 has a fourth horizontal portion 319 behind the third inclined portion 318, and the fourth horizontal portion 319 is a horizontally arranged flange plate and is connected to the bottom of the second cover shell 312.

[0044] Automatic defocusing device 11 Figure 12-13 As shown, the coke-cleaning cylinder 110, a tie rod 120, and a furnace-poking claw 130 are included. The coke-cleaning cylinder 110 includes a base 111 located outside the second housing 312, a sleeve 113 fixedly mounted at the front end of the base 111 (with the end adjacent to the chute 200 as the front end) and extending into the second housing 312, and a telescopic end 112 that is telescopically connected to the base 111 within the sleeve 113. The coke-cleaning cylinder 110 is connected to the rear end outer wall of the second housing 312 via the sleeve 113. The tie rod 120 is located within the second housing 112, with one end extending into the sleeve 113 and connected to the telescopic end 112. The other end of the tie rod 120 is connected to the furnace-poking claw 130. The telescopic end 112 is coaxially arranged within the sleeve 113. The inner diameter of the front end of the sleeve 113 corresponds to the outer diameter of the rear end of the tie rod 120, thereby controlling the smooth axial movement of the tie rod 120 along the sleeve 113. The automatic coke cleaning device 11 drives the furnace-poking claw 130 to clean the coke on the upper groove through the coke cleaning cylinder 110. The telescopic end 112 of the coke cleaning cylinder 110 is set in the sleeve 113. The sleeve 113 is convenient for the installation of the coke cleaning cylinder 110 at the rear end of the second cover shell 312, and is also convenient for limiting the pull rod 120 to move smoothly along the axial direction of the sleeve 113, thereby realizing precise control of the furnace-poking claw 130.

[0045] In some preferred embodiments, the telescopic end 112 of the coke cleaning cylinder 110 is telescopically extended and retracted, and the pull rod 120 is horizontally arranged along the movement direction of the telescopic end 112. A plurality of furnace-poking claws 120 can be arranged at intervals on the pull rod 120. In the initial state, the furnace-poking claws 120 are 300 mm away from the upper groove of the chute 200.

[0046] In some preferred embodiments, a sleeve mounting plate 140 is provided on the surface of the sleeve 113, and the sleeve mounting plate 140 is connected to the rear end surface of the second cover shell 112 outside the second cover shell 312. A compression spring 150 is also provided between the sleeve mounting plate 140 and the second cover shell 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 decoking cylinder 110 moves, the compression spring 150 can buffer the decoking cylinder 110 to avoid damage to the installation location, thereby improving the operation reliability of the automatic decoking device 11.

[0047] In some preferred embodiments, a peep mirror 314 is provided on the top of the second cover 312 and an observation door 313 is provided at the rear end to facilitate observation of the working status of the chute 200 and the automatic decoking device 11.

[0048] The fully enclosed chute 2 operates as follows: The molten material enters the chute 200 from the upper slot and flows downward along the surface of the flow guide 220. The first, second, and third housings 311, 312, and 315 form a sealed housing assembly, sealing the molten material before it flows into the primary cooling device 3. During this process, the automatic coke removal device 11, using the coke removal cylinder 110 to drive the furnace claw 130, removes coke from the upper slot of the chute 200.

[0049] Example 2 like Figure 2 As shown, this embodiment provides a method for solid-state recovery and redissolution of alkali recovery boiler melt, which is implemented using the above-mentioned solid-state recovery and redissolution processing system for alkali recovery boiler melt, including: S1, the 800-900°C molten material generated by combustion in the alkali recovery boiler 1 is led out through the fully enclosed chute 2 to the inlet of the primary cooling device 3, enters the primary cooling device 3 and is cooled to 200-400°C to form solid salt, and then is transported through the conveying device 4 to the secondary cooling device 5 and further cooled to 50-200°C to obtain solid salt; S2. The cooled solid salt enters the crushing device 6, where it is crushed to obtain solid salt fine particles with a particle size of less than 1 mm. The solid salt fine particles are transported to the dissolving device 8 via the conveying device 2 7 to react and dissolve with the dilute white liquor to form green liquor.

[0050] During the above treatment process, the smelt chute 2, the primary cooler 3, the conveying equipment 4, and the secondary cooling equipment 5 all use desalted water for indirect cooling. The desalted water is sent to the above-mentioned four cooling equipment for heat exchange through the desalted water inlet main pipe 12. The desalted water after heat exchange is collected and enters the desalted water return main pipe 13 and is sent to the deaerator 10. This can increase the temperature of the desalted water entering the deaerator 10 and reduce the steam consumption required for deoxygenation. Online instruments such as flow rate and temperature can be set on the desalted water inlet main pipe 12 and / or the desalted water return main pipe 13 to monitor the entire cooling water system in real time to ensure system stability.

[0051] During the above processing, the negative pressure dust removal equipment 9 is started to collect the dust generated during the operation of the primary cooling device 3, the conveying equipment 1 4, the secondary cooling device 5, the crushing equipment 6, and the conveying equipment 2 7. The primary cooling device 3, the conveying equipment 1 4, the secondary cooling device 5, the crushing equipment 6, and the conveying equipment 2 7 are all in negative pressure operation to avoid dust on site.

[0052] During the above treatment process, the automatic coke cleaning device 11 configured in the fully enclosed chute 2 can be set to regularly clean the coke on the upper slot, or the operator can clean it through remote control.

[0053] In the treatment process of the present invention, desalted water is used as a cooling medium. After absorbing the heat of the melt, the desalted water is used as feed water for the deaerator of the alkali recovery boiler, which can reduce the steam consumption of the deaerator, recover the waste heat of the melt, and improve the energy utilization rate of the alkali recovery boiler.

[0054] Example 3 The secondary cooling device 5 can adopt the existing spiral cooler, with a rotating shaft set in the shell and hollow spiral blades set on the rotating shaft. Cooling is performed by the coolant flowing in the spiral blades. Since the spiral blades play a conveying role when rotating, the cooling time of the melt is too short and the cooling effect is difficult to guarantee.

[0055] This embodiment provides a spiral cooler 100 for cooling boiler melt, which improves the existing spiral cooler and improves the cooling effect, and is used to further quickly cool the melt to 50-200°C. Figure 14-15 As shown, the spiral cooler 100 for cooling the boiler melt includes: The housing 101 has an inlet 105 and an outlet at both ends thereof; The cooling conveyor assembly includes a rotating shaft 102 that rotates within a housing 101. A water inlet core 103 is disposed within the rotating shaft 102, forming a reflux chamber 121 between the rotating shaft 102 and the water inlet core 103. Extending axially from the rotating shaft 102 are a first spiral blade 122, a plurality of paddle blades 123, and a second spiral blade 124, all of which are hollow and communicate with the reflux chamber 121. The first spiral blade 122 is located at the end of the rotating shaft 102 near the discharge port, the second spiral blade 124 is located at the end of the rotating shaft 102 near the feed port 105, and the paddle blade 123 is located between the first spiral blade 122 and the second spiral blade 124. The pitch h2 of the second spiral blade 124 is greater than the pitch h1 of the first spiral blade 122. Setting h2>h1 is intended to allow the melt to enter quickly and exit slowly, extending the cooling time and improving the cooling effect.

[0056] The hollow inner cavities of the first spiral blade 122, the paddle blade 123, and the second spiral blade 124 are each provided with a water inlet component (e.g., a water inlet pipe) communicating with the water inlet core pipe 103. Each hollow inner cavity is also provided with a water outlet component (e.g., a communication hole) communicating with the reflux chamber 121. This allows coolant to flow from the water inlet core pipe 103 into the first spiral blade 122, the paddle blade 123, and the second spiral blade 124, cooling the melt. After absorbing heat, the coolant then flows out through the reflux chamber 121. A rotary joint 104 is provided at one end of the rotating shaft 102. The rotary joint 104 is provided with a water inlet 141 communicating with the water inlet core pipe 103 and a water outlet 142 communicating with the reflux chamber 121.

[0057] In a preferred embodiment, the first spiral blade 122 and the second spiral blade 124 are both discontinuous spiral blades formed by a plurality of sub-spiral blades, each of which is connected to the water inlet core pipe 103 and the reflux chamber 121. Compared with the continuous spiral blade, the discontinuous design allows the coolant to enter each sub-spiral blade at the same time, which helps to improve the cooling effect and cooling timeliness. The first spiral blade 122 is located at the discharge port end to facilitate the discharge of the melt that is gradually converted into a solid state by cooling, and to prevent the melt from coking and adhering to the paddle blade 123. The paddle blade 123 is fan-shaped, and a plurality of paddle blades 123 are located between the first spiral blade 122 and the second spiral blade 124 and are arranged axially at intervals along the rotating shaft 102. The fan-shaped paddle blade 123 reserves space for the melt to flow, which is convenient for cooling and stirring. The second spiral blade 124 can avoid insufficient power for the melt to flow at the feed port 105, so as to prevent the melt from flowing too slowly to the paddle blade 123 or accumulating at the feed port 105.

[0058] like Figure 16-17 As shown, the housing 101 is a shell structure with an interlayer cavity. Multiple partitions 107 are provided in the interlayer cavity along the axial direction of the housing 101. The multiple partitions 107 divide the interlayer cavity into multiple cold chamber units 108 for accommodating coolant. The multiple partitions 107 divide the interlayer cavity into multiple cold chamber units 108, and the partitions 107 occupy a flow cross section, which can reduce the amount of coolant used.

[0059] In a preferred embodiment, the ends of adjacent cold chamber units 108 are interconnected to form an S-shaped cold chamber. The circuitous flow of the coolant in the S-shaped cold chamber increases the flow path of the coolant, thereby improving the cooling effect.

[0060] Furthermore, the shell 101 is a U-shaped structure in the horizontal direction (i.e. perpendicular to the axial direction of the rotating shaft 102), and the U-mouth end of the shell 101 is covered with a cover plate 106, on which an inlet 105 is provided. The bottom of the shell 101 opposite to the inlet 105 is provided with an outlet.

[0061] In this embodiment, the coolant in the spiral cooler 100 for cooling the boiler melt can be desalted water. After heat exchange, the desalted water is passed to the deaerator 10 via the desalted water return main pipe 13. Two sets of cooling and conveying components are provided, which can improve the cooling effect. The drive device is connected to one of the rotating shafts 102. Gears 125 are provided on both rotating shafts 102, and the two rotating shafts 102 are meshed through the gears to drive the rotation of the other rotating shaft 102, facilitating synchronous reverse rotation and transporting the melt in the axial direction. The drive device is preferably a motor, and the output end of the motor is connected to one of the rotating shafts 102 via a transmission belt.

[0062] In the above spiral cooler 100 for cooling the melt in the boiler, the melt flows into the paddle blades at a slow flow rate, and the stirring provided by the paddle blades can extend the cooling time. The first spiral blade is arranged at the discharge port to transport the cooled melt (or solid) out of the outer shell to prevent the melt from coking on the paddle blades when cooled; the paddle blades and the first spiral blades are arranged in sections to ensure a better cooling effect under the premise of ensuring the conveying effect.

Claims

1. A processing system for solid state recovery and redissolution of alkali recovery boiler melt, characterized in that: The invention comprises a fully enclosed chute (2), a cooling device, a crushing device (6) and a dissolving device (8) arranged in sequence along the material flow direction, wherein the fully enclosed chute (2) is provided with an automatic coke cleaning device (11) for cleaning coke from the upper slot; It also includes a waste heat recovery pipeline for utilizing the desalted water of the alkali recovery boiler (1), wherein the waste heat recovery pipeline is connected to the fully enclosed chute (2) and the cooling device for introducing the desalted water for cooling.

2. The solid state recovery and redissolution processing system for alkali recovery boiler melt according to claim 1, characterized in that: The cooling device comprises a primary cooling device (3), a conveying device (4), and a secondary cooling device (5) arranged along the material flow direction, and the fully enclosed chute (2), the primary cooling device (3), the conveying device (4), and the secondary cooling device (5) are each provided with a cooling liquid inlet and a cooling liquid outlet.

3. The solid state recovery and redissolution processing system for alkali recovery boiler melt according to claim 2, characterized in that: The waste heat recovery pipeline includes a main recovery pipe (14) that directly leads the desalted water to the deaerator (10), and a desalted water inlet main pipe (12) and a desalted water return main pipe (13) arranged on the main recovery pipe (14). The desalted water inlet main pipe (12) is connected to the cooling liquid inlet of the fully enclosed chute (2), the first-level cooling device (3), the conveying equipment (4), and the second-level cooling device (5) for conveying the desalted water. The desalted water return main pipe (13) is connected to the cooling liquid outlet of the fully enclosed chute (2), the first-level cooling device (3), the conveying equipment (4), and the second-level cooling device (5) for recovering the desalted water after heat exchange.

4. The solid state recovery and redissolution processing system for alkali recovery boiler melt according to claim 2, characterized in that: A second conveying device (7) is provided between the crushing device (6) and the dissolving device (8), and the processing system further comprises 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).

5. The solid state recovery and redissolution processing system for alkali recovery boiler melt according to claim 1, characterized in that: The fully enclosed chute (2) comprises a chute (200) and a cover assembly, wherein the chute (200) and the cover assembly form a sealed slag discharge channel whose upper end is connected to the alkali recovery boiler (1) and whose lower end is connected to the cooling device; The cover assembly comprises a first cover (311) welded to the furnace wall of the alkali recovery boiler (1), a second cover (312) arranged above the chute (200) and connected to the first cover (311) and the chute wall of the chute (200), and a third cover (315) connected to the lower notch of the chute (200) and the bottom of the second cover (312), wherein an expansion joint (320) is provided at the lower end of the third cover (315) for absorbing vertical thermal expansion.

6. The solid state recovery and redissolution processing system for alkali recovery boiler melt according to claim 5, characterized in that: The second cover shell (312) is in the shape of a square shell and is arranged horizontally in the longitudinal direction. The bottom of the second cover shell (312) is provided with a second inclined portion (317) correspondingly connected to the top of the chute wall (200). The front end of the second cover shell (312) is correspondingly connected to the first cover shell (311) via a first connecting plate (316). The front end of the third cover shell (315) is provided with a third inclined portion (318) correspondingly connected to the outer wall of the lower notch of the chute (200), and the third cover shell (315) is provided with a fourth horizontal portion (319) behind the third inclined portion (318) and connected to the bottom of the second cover shell (312).

7. The solid state recovery and redissolution processing system for alkali recovery boiler melt according to claim 6, characterized in that: The automatic coke cleaning device (11) includes a coke cleaning cylinder (110), a pull rod (120) and a furnace-poking claw (130). The coke cleaning cylinder (110) includes a base (111) located outside a second cover shell (312), a sleeve (113) fixedly arranged at the front end of the base (111) and extending into the second cover shell (312), and a telescopic end (112) telescopically connected to the base (111) in the sleeve (113). The coke cleaning cylinder (110) is connected to the outer wall of the rear end of the second cover shell (312) through the sleeve (113). The pull rod (120) is located in the second cover shell (112) and one end thereof enters the sleeve (113) and is connected to the telescopic end (112). The other end of the pull rod (120) is connected to the furnace-poking claw (130).

8. A method for solid state recovery and redissolution of alkali recovery boiler melt according to any one of claims 1 to 7, characterized in that: include: S1, the 800-900°C molten material generated by combustion in the alkali recovery boiler (1) is drawn out through a fully enclosed chute (2), and then cooled to 50-200°C by a cooling device to obtain solid salt; S2. The cooled solid salt enters the crushing device (6) for crushing to obtain solid salt fine particles. The solid salt fine particles are transported to the dissolving device (8) to react and dissolve with the dilute white liquor to form green liquor.

9. The method for treating a molten material solid state recovery and redissolution treatment system of an alkali recovery boiler according to claim 8, characterized in that: In step S1, the 800-900°C molten material is drawn out through the fully enclosed chute (2), firstly enters the primary cooling device (3) to be cooled to 200-400°C, and then enters the secondary cooling device (5) to be further cooled to 50-200°C to obtain solid salt.

10. The method for treating a alkali recovery boiler melt solid state recovery and redissolution treatment system according to claim 8, characterized in that: In step S2, the solid salt fine particles with a particle size of less than 1 mm are obtained by crushing.

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