Indirect heating treatment device and treatment process based on high-temperature flue gas

Abstract

The invention discloses an indirect heating treatment device and process based on high-temperature flue gas, the indirect heating treatment device comprises a first combustion chamber, a second combustion chamber, an indirect heating dryer and an indirect heating decomposition furnace, the indirect heating dryer is composed of a rotary cylinder and an outer heating cover, and an outer heating cavity is formed in the outer heating cover; hot flue gas enters the outer heating cavity through the gas inlet and exchanges heat with materials in the rotary cylinder in a countercurrent manner; the indirect heating decomposition furnace is composed of a rotary hearth and a heat exchange pipe cavity, materials enter the rotary hearth from a discharging port of the dryer, hot smoke enters the heat exchange pipe cavity from a second combustion chamber and conducts countercurrent flow heat exchange with the materials in the rotary hearth, and then heat exchange waste heat is reused for the dryer; according to the device, the materials are indirectly heated through high-temperature flue gas to achieve drying and thermal decomposition of the materials, the heat energy utilization rate is increased, and the process can be suitable for application scenes where the materials cannot be secondarily polluted or flue gas making contact with the materials cannot be directly discharged.

Description

Technical Field

[0001] The present application relates to the technical field of solid waste treatment, and in particular to an indirect heating treatment device suitable for requiring that materials cannot be secondarily contaminated or flue gas contacting the materials cannot be directly discharged, and specifically to an indirect heating treatment device and treatment process based on high-temperature flue gas. Background Art

[0002] In the field of solid waste treatment, some materials cannot be polluted for the second time, or the flue gas that contacts the materials cannot be discharged directly, such as fly ash from garbage combustion, blast furnace slag, steel slag and converter dust, fly ash, slag, coal gangue, desulfurization gypsum, chemical waste (such as coke powder, coke slag, desulfurization waste residue), etc. Among them, materials such as blast furnace slag, steel slag, fly ash and fly ash from garbage combustion need to be heated during the treatment process, and can be recycled after treatment. However, these materials cannot be mixed with other flue gases during the drying or pyrolysis process, especially secondary pollutants generated during the incineration process of garbage such as fly ash. The flue gas volatilized during the treatment process must be treated by secondary combustion, otherwise the harmful substances in the gas produced will pollute the environment.

[0003] Take fly ash as an example. The composition of fly ash is complex and contains toxic and harmful substances, mainly heavy metals and dioxins. The heavy metals in fly ash cannot be naturally degraded and have low solubility. Once they enter the environment, they will cause serious pollution to water bodies, soil and organisms. Dioxins in fly ash are extremely toxic and stable and can pose a serious threat to human health. Some waste incineration fly ash may contain radioactive substances, such as uranium and thorium, which pose potential threats to the environment and human health. Therefore, it is of great significance to properly handle waste incineration fly ash.

[0004] From the current fly ash treatment process, resource utilization is more marketable. The current method of resource utilization of fly ash is to use a series of process treatments to produce building materials and recover heavy metals, ensuring that the treatment process meets the relevant pollution control standards and requirements. At present, the methods of fly ash resource production of building materials mainly include water washing-cement kiln co-treatment to produce cement, high-temperature sintering to produce light bone particles (ceramsite), cementitious materials, etc. However, the current systems and processes for processing fly ash have problems such as complex equipment, relatively high system energy consumption and high processing costs. Therefore, there are still many shortcomings in the current fly ash resource treatment process, and it is necessary to propose a technical solution that can reduce energy consumption and reduce production costs. Summary of the invention

[0005] The present application provides an indirect heating treatment device and a treatment process based on high-temperature flue gas, which are used to solve the problems of high energy consumption and high treatment cost in the current fly ash resource treatment process.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] On the one hand, the present application provides an indirect heating treatment device based on high-temperature flue gas, comprising a first combustion chamber, a second combustion chamber, an indirect heating dryer and an indirect heating decomposition furnace;

[0008] The indirect heating dryer comprises a rotary drum and an external heating hood arranged on the periphery of the rotary drum, an external heating chamber is formed between the rotary drum and the external heating hood, a spiral partition is arranged in the external heating chamber, an air inlet and an air outlet are respectively arranged at two ends of the external heating hood along the length direction thereof, the air inlet is connected to the exhaust end pipe of the first combustion chamber, the hot flue gas discharged from the first combustion chamber flows along the spiral partition in the external heating hood and performs heat exchange with the material in the rotary drum, and the air outlet is connected to the first blower pipe; a material inlet and a material outlet are respectively arranged at two ends of the rotary drum along the length direction thereof, the flow direction of the hot flue gas in the external heating chamber is opposite to the flow direction of the material entering the rotary drum, and a material turning structure for turning the material and pushing the material forward is arranged in the rotary drum;

[0009] The indirect heating decomposition furnace includes a rotary furnace and a heat exchange tube cavity arranged outside the rotary furnace. A feed port, a discharge port and an exhaust port are arranged on the rotary furnace. The feed port of the rotary furnace is connected with the discharge port of the rotary cylinder. A hot air inlet and a heat exchange air outlet are respectively arranged at both ends of the heat exchange tube cavity. The hot air inlet is connected with the flue gas outlet of the second combustion chamber, and the heat exchange air outlet is connected with the air inlet of the external heating cover. The flow direction of the hot flue gas in the heat exchange tube cavity is opposite to the flow direction of the material in the rotary furnace.

[0010] Furthermore, in the above technical solution, the rotating cylinder is arranged horizontally and tilted along its length direction, and the vertical height of the feed port on the rotating cylinder is higher than the vertical height of the discharge port arranged thereon.

[0011] Furthermore, the rotary hearth is arranged horizontally and tilted along its length direction, and the vertical height of the feed port on the rotary hearth is higher than the vertical height of the discharge port arranged thereon.

[0012] Furthermore, a material turning structure for turning the materials and pushing the materials forward is provided in the rotary furnace.

[0013] Furthermore, a first mounting base is arranged below the rotating cylinder, and two first roller supports are arranged oppositely on the first mounting base, and a first roller is arranged on the first roller support. First support rings for adapting and connecting with the first rollers are respectively arranged at both ends of the rotating cylinder along its length direction, and the first support ring is a circle of rolling rings arranged on the outer wall of the rotating cylinder, and the rolling rings are fixed on the outer wall of the rotating cylinder through multiple connecting seats; a first driving mechanism is also arranged on the first mounting base, and the first driving mechanism is used to drive the rotating cylinder to rotate with its central axis as the rotation axis, and a power output shaft of the first driving mechanism is connected to the first driving gear, and a circle of first driven gear for adapting and meshing transmission with the first driving gear is arranged on the outer wall of the rotating cylinder.

[0014] Furthermore, a second mounting base is arranged below the rotary furnace, and two second roller supports are arranged oppositely on the second mounting base, and second rollers are arranged on the second roller supports. Second support rings for adapting and connecting with the second rollers are respectively arranged at both ends of the rotary furnace along its length direction, and the second support ring is a circle of rolling rings arranged on the outer wall of the rotary furnace, and the rolling rings are fixed on the outer wall of the rotary furnace through multiple connecting seats; a second driving mechanism is also arranged on the second mounting base, and the second driving mechanism is used to drive the rotary furnace to rotate with its central axis as the rotation axis, and the power output shaft of the second driving mechanism is connected to the second driving gear, and a circle of second driven gear for adapting and meshing transmission with the second driving gear is arranged on the outer wall of the rotary furnace.

[0015] Furthermore, a plurality of spiral partitions are evenly distributed in a spiral shape on the inner wall of the external heating hood, and the spiral partitions are used to spirally guide the hot flue gas entering from the air inlet to the air outlet. The air outlet discharges the heat-exchanged flue gas to the atmosphere through the first blower. The temperature range of the hot flue gas entering the air inlet is 450°C to 650°C.

[0016] Furthermore, a second spiral baffle is provided in the heat exchange tube cavity, and the hot flue gas flows along the second spiral baffle in the heat exchange tube cavity and exchanges heat with the material in the rotary furnace; a plurality of second spiral baffles are evenly distributed on the inner wall of the heat exchange tube cavity in a spiral shape, and the spiral baffles are used to spirally guide the hot flue gas introduced from the hot air inlet to the heat exchange air outlet, and the heat exchange air outlet discharges the heat exchanged flue gas to the external heating cover of the indirect heating dryer or directly into the atmosphere through the second blower; the temperature range of the hot flue gas introduced into the hot air inlet is 700℃~850℃.

[0017] Furthermore, the material turning structure inside the rotating cylinder includes a plurality of material lifting plates arranged on the inner wall of the rotating cylinder, and the plurality of material lifting plates are evenly spaced in the radial direction of the rotating cylinder, and the length direction of each material lifting plate forms an angle with the central axis of the rotating cylinder; or, the plurality of material lifting plates form a plurality of material lifting groups on the inner wall of the rotating cylinder, and each material lifting group includes a plurality of material lifting plates evenly spaced in the radial direction of the rotating cylinder, and the material lifting plates in two adjacent material lifting groups are staggered.

[0018] Furthermore, the material turning structure in the rotary furnace includes a plurality of material lifting plates arranged on the inner wall of the rotary furnace, and the plurality of material lifting plates are evenly spaced in the radial direction of the rotary furnace, and the length direction of each material lifting plate forms an angle with the central axis of the rotary furnace; or, a plurality of material lifting plates form a plurality of material lifting groups on the inner wall of the rotary furnace, and each material lifting group includes a plurality of material lifting plates evenly spaced in the radial direction of the rotary furnace, and the material lifting plates in two adjacent material lifting groups are staggered.

[0019] Furthermore, the discharge port of the rotary drum is connected to a material conveying device, and the material conveying device is used to convey the dried material discharged from the rotary drum to the indirect heating decomposition furnace.

[0020] Furthermore, an air-cooling tube cavity is also provided on the rotary furnace, and the heat exchange tube cavity and the air-cooling tube cavity are adjacently arranged on the rotary furnace, the heat exchange tube cavity is close to the feed port of the rotary furnace, and the air-cooling tube cavity is close to the discharge port of the rotary furnace; the heat exchange tube cavity is used for thermally desorbing the fly ash fed into the rotary furnace, so that the fly ash decomposes into harmful gases, and the harmful gases enter the calcining furnace from the exhaust port of the rotary furnace; cold air inlet and heat exchange cold air outlet are respectively arranged at both ends of the air-cooling tube cavity; the air-cooling tube cavity is used for cooling the fly ash after thermal desorption.

[0021] Furthermore, a first burner is arranged at the end of the first combustion chamber, and the first burner is used to ignite the combustible gas introduced into the first combustion chamber to generate hot flue gas; a second burner is arranged at the end of the second combustion chamber, and the second burner is used to ignite the combustible gas introduced into the second combustion chamber to generate hot flue gas; the outer shells of the first combustion chamber and the second combustion chamber are both made of carbon steel, and the interiors of the first combustion chamber and the second combustion chamber are both provided with insulation layers and high-temperature resistant casting materials; the connecting pipe between the first combustion chamber and the indirect heating dryer is a carbon steel pipe with an insulation layer and high-temperature resistant casting materials; the connecting pipe between the second combustion chamber and the indirect heating decomposition furnace is a carbon steel pipe with an insulation layer and high-temperature resistant casting materials.

[0022] On the other hand, the present application provides an indirect heating treatment process based on high-temperature flue gas, using the above-mentioned indirect heating treatment device based on high-temperature flue gas, comprising the following steps:

[0023] S1: Send the hot flue gas with a temperature range of 450℃~650℃ in the first combustion chamber into the external heating cover of the indirect heating dryer, and send the material to be dried into the rotary cylinder of the indirect heating dryer. The hot flue gas flows along the spiral diaphragm in the external heating cover and performs countercurrent heat exchange with the material in the rotary cylinder. The flue gas that has completed the heat exchange flows into the first blower from the air outlet of the external heating cover, and is then discharged to the atmosphere by the first blower. The dried material discharged from the discharge port of the rotary cylinder is sent to the rotary hearth of the indirect heating decomposition furnace;

[0024] S2: The hot flue gas with a temperature range of 700℃~850℃ in the second combustion chamber is sent into the heat exchange tube cavity of the indirect heating decomposition furnace. The hot flue gas flows along the heat exchange tube cavity and performs countercurrent heat exchange with the material in the rotary furnace for thermal desorption. The flue gas that has completed the heat exchange is discharged from the heat exchange air outlet of the heat exchange tube cavity to the external heating cover of the indirect heating dryer to heat exchange and heat up the material in the rotary cylinder.

[0025] Compared with the prior art, this application has at least the following beneficial effects:

[0026] The present application dries and thermally desorbs fly ash through an indirect heating dryer and an indirect heating decomposition furnace. This heating method can be applied to application scenarios where the material cannot be secondary polluted or the flue gas contacting the material cannot be directly discharged. Compared with the traditional technology of low-temperature thermal desorption treatment in an inert gas atmosphere, the present application uses an indirect heating dryer and an indirect heating decomposition furnace for indirect heating to avoid energy loss caused by direct heating and improve thermal efficiency. In addition, since the indirect heating decomposition furnace requires hot flue gas at a higher temperature, and the hot flue gas still has residual heat to be used after heating, the temperature of the hot flue gas required by the indirect heating dryer is relatively low. Therefore, the device can transport the flue gas discharged from the indirect heating decomposition furnace to the air inlet end of the hot flue gas of the indirect heating dryer through a fan and a pipeline, which is beneficial to the heat exchange and heating of the material in the indirect heating dryer, thereby realizing heat recovery and reuse, reducing the consumption of additional energy, and realizing internal recycling of energy. Therefore, the indirect heating treatment device and treatment process based on high-temperature flue gas provided by the present application can reduce the system's processing energy consumption, improve the efficiency of heat recovery and reuse, and reduce processing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. It should be understood that the specific shapes and structures shown in the drawings should not usually be regarded as limiting conditions for implementing the present application; for example, based on the technical concepts and exemplary drawings disclosed in the present application, those skilled in the art are able to easily make routine adjustments or further optimizations to the increase / decrease / attribution division, specific shapes, positional relationships, connection methods, and dimensional ratios of certain units (components).

[0028] Figure 1 This is a schematic diagram of the structure of an indirect heating treatment device based on high-temperature flue gas provided by the present application in an embodiment, wherein the direction of the arrow indicates the flow direction of the flue gas;

[0029] Figure 2 A schematic diagram of the arrangement of the material lifting plates in the rotary drum of an indirect heating dryer in one embodiment;

[0030] Figure 3 It is a schematic diagram of the arrangement of the material lifting plates in the rotary drum of an indirect heating dryer in another embodiment;

[0031] Figure 4 It is a system flow chart of the fly ash resource processing system in this application in one embodiment;

[0032] Figure 5 for Figure 4 A partial enlarged schematic diagram of part A;

[0033] Figure 6 for Figure 4 A partial enlarged schematic diagram of part B.

[0034] Description of reference numerals:

[0035] 1. Feeding buffer bin; 2. Double harrow extrusion screw; 3. Measuring belt conveyor; 4. Sealed belt conveyor; 5. Bag dust collector; 6. First screw feeder;

[0036] 7. Indirect heating dryer; 701. Rotating cylinder; 702. Feed inlet; 703. Discharge outlet; 704. External heating cover; 705. Air inlet; 706. Air outlet; 707. First mounting base; 708. First roller support; 709. First support ring; 710. First driving mechanism; 711. First driving gear; 712. First driven gear; 713. Lifting plate;

[0037] 8. Gate valve; 9. Discharge valve; 10. First diffusion cyclone separator; 11. Gate valve; 12. Discharge valve; 13. Screw conveyor; 14. Bucket elevator; 15. Condensation tower; 16. First gas-to-gas heat exchanger; 17. First induced draft fan; 18. Combustion assembly; 19. First combustion chamber; 20. First blower; 21. Transition silo; 22. Combustion assembly; 23. First alkali washing tower; 24. Second screw feeder; 25. Combustion chamber; 26. Second alkali washing tower;

[0038] 27. Indirect heating decomposition furnace; 2701. Rotary furnace; 2702. Feed inlet; 2703. Discharge outlet; 2704. Exhaust outlet; 2705. Heat exchange tube cavity; 2706. Hot air inlet; 2707. Heat exchange air outlet; 2708. Air cooling tube cavity; 2709. Cold air inlet; 2710. Heat exchange cold air outlet; 2711. Second mounting base; 2712. Second roller support; 2713. Second support ring; 2714. Second driving mechanism; 2715. Second driving gear; 2716. Second driven gear;

[0039] 28. calcining furnace; 29. ​​chimney; 30. gate valve; 31. second blower; 32. circulating water pool; 33. discharge valve; 34. denitrification system; 35. sodium hydroxide dissolving tank; 36. second diffusion cyclone separator; 37. second gas-to-gas heat exchanger; 38. carbon powder bin; 39. gate valve; 40. quenching tower; 41. discharge valve; 42. discharge valve; 43. circulating water tank 44. lime bin; 45. first water-cooled screw conveyor; 46. bag filter; 47. discharge valve; 48. second water-cooled screw conveyor; 49. grinding mill; 50. combustion assembly; 51. second combustion chamber; 52. third blower; 53. gate valve; 54. collecting tank; 55. second induced draft fan; 56. supply fan. DETAILED DESCRIPTION

[0040] The present application is further described below in detail through specific embodiments in conjunction with the accompanying drawings.

[0041] In the description of this application: unless otherwise specified, "plurality" means two or more. The terms "first", "second", etc. in this application are intended to distinguish the objects referred to, and do not have special meanings in terms of technical connotations (for example, they should not be understood as emphasizing the importance or order, etc.). Expressions such as "including", "comprising", "having", etc. also mean "not limited to" (certain units, components, materials, steps, etc.).

[0042] The terms such as "upper", "lower", "left", "right" etc. used in this application are usually used to facilitate intuitive understanding by comparing with the accompanying drawings, and are not absolute limitations on the positional relationship in the actual product. Without departing from the technical concept disclosed in this application, changes in these relative positional relationships should also be considered as the scope of this application.

[0043] In view of the characteristics of some materials, they cannot be mixed with other flue gases during the drying or pyrolysis process, especially secondary pollutants generated during the incineration of waste such as fly ash. The flue gas volatilized during the treatment process must be treated with secondary combustion, otherwise the harmful substances in the gas produced will pollute the environment. Based on this, the present application provides an indirect heating treatment device and treatment process based on high-temperature flue gas. The treatment device can dry or pyrolyze pollutants such as fly ash by indirect heating. This indirect heating method can not only reduce pollution, but also reduce the energy consumption of subsequent exhaust gas treatment. The structural principle of the indirect heating treatment device based on high-temperature flue gas and the process of the treatment process are described in detail below in conjunction with the accompanying drawings.

[0044] Embodiment 1

[0045] This embodiment provides an indirect heating treatment device based on high temperature flue gas, see Figure 1, which includes a first combustion chamber 19, a second combustion chamber 51, an indirect heating dryer 7 and an indirect heating decomposition furnace 27. Among them: the indirect heating dryer 7 includes a rotary cylinder 701 and an external heating cover 704 arranged on the periphery of the rotary cylinder 701, an external heating chamber is formed between the rotary cylinder 701 and the external heating cover 704, a spiral baffle is arranged in the external heating chamber, an air inlet 705 and an air outlet 706 are respectively arranged at both ends of the length direction of the external heating cover 704, the air inlet 705 is connected to the exhaust end pipe of the first combustion chamber 19, the hot flue gas discharged from the first combustion chamber 19 flows along the spiral baffle in the external heating cover 704 and exchanges heat with the material in the rotary cylinder 701, and the air outlet is connected to the first blower pipe; the rotary cylinder 701 is provided with a feed inlet 702 and a discharge outlet 703 at both ends of the length direction, and the flow direction of the hot flue gas in the external heating chamber is opposite to the flow direction of the material entering the rotary cylinder 701 , a turning structure for turning the material and pushing the material forward is provided in the rotary cylinder 701; the indirect heating decomposition furnace 27 comprises a rotary furnace 2701 and a heat exchange tube cavity 2705 arranged outside the rotary furnace 2701; a feed port 2702, a discharge port 2703 and an exhaust port 2704 are arranged on the rotary furnace 2701; the feed port 2702 of the rotary furnace 2701 is connected with the discharge port 2703 of the rotary cylinder 701; hot air inlet 2706 and heat exchange air outlet 2707 are respectively provided at both ends of the heat exchange tube cavity 2705; the hot air inlet 2706 is connected with the flue gas outlet of the second combustion chamber 51; the heat exchange air outlet 2707 is connected with the air inlet 705 of the external heating cover 704; the flow direction of the hot flue gas in the heat exchange tube cavity 2705 is opposite to the flow direction of the material in the rotary furnace 2701. In addition, an air-cooling tube cavity 2708 may be provided on the rotary furnace 2701. The heat exchange tube cavity 2705 and the air-cooling tube cavity 2708 are adjacent to each other on the rotary furnace 2701, the heat exchange tube cavity 2705 is close to the feed port of the rotary furnace 2701, and the air-cooling tube cavity 2708 is close to the discharge port 2703 of the rotary furnace 2701; the heat exchange tube cavity 2705 is used to thermally desorb the fly ash fed into the rotary furnace 2701, so that the fly ash decomposes into harmful gases, and the harmful gases enter the calcining furnace from the exhaust port of the rotary furnace 2701; cold air inlet 2709 and heat exchange cold air outlet 2710 are respectively provided at both ends of the air-cooling tube cavity 2708; the air-cooling tube cavity 2708 is used to cool the fly ash after thermal desorption.

[0046] In this embodiment, combustible gas such as natural gas, coal gas, etc. is used to generate high-temperature hot flue gas in the combustion chamber under the action of a burner. The temperature of the hot flue gas can be adjusted according to the production requirements of the material. A burner is arranged at the end of the combustion chamber. The outer shell of the combustion chamber is made of carbon steel, and an insulation layer and high-temperature resistant casting material are arranged inside. The combustible gas burns in the combustion chamber to form high-temperature flue gas. A flange is arranged at the flue gas outlet end of the combustion chamber. The flue gas outlet of the combustion chamber is connected to the air inlet of the rotary equipment (indirect heating dryer 7, indirect heating decomposition furnace 27) through a pipeline. The outer shell of the connecting pipeline is made of carbon steel, and the internal structure is an insulation layer and a high-temperature resistant casting material. An external heating cover 704 is arranged outside the rotary cylinder 701 of the indirect heating dryer 7, a cavity is formed between the external heating cover 704 and the rotary cylinder, a spiral partition is arranged in the cavity, an air inlet of hot flue gas is close to the discharge end of the rotary cylinder, the air inlet of hot flue gas is arranged on the external heating cover 704, and an air outlet of hot flue gas is close to the feed end of the rotary cylinder 701 and arranged on the external heating cover 704. The hot flue gas travels along the spiral partition in the cavity of the external heating cover 704, countercurrent heating is performed, the heat radiation action time of the material is increased, and the flue gas after heat exchange can be reused, saving energy.

[0047] The indirect heating treatment device based on high-temperature flue gas provided in the present application mainly utilizes combustible fuel to provide hot flue gas to indirectly heat the rotary equipment, so that the material inside the rotary equipment is dried or pyrolyzed through thermal radiation. This heating method can be suitable for application scenarios that require that the material cannot be secondary contaminated or the flue gas that contacts the material cannot be directly discharged. The device utilizes fuel to provide high-temperature flue gas and protects the equipment. The flue gas used can also be reused.

[0048] The fly ash is taken as the material to be treated and the indirect heating treatment device based on high-temperature flue gas is described in detail below.

[0049] The fly ash after water washing contains moisture, so it must be dried and pyrolyzed before the final product is obtained. However, since the fly ash still contains a small amount of harmful substances and heavy metals after water washing, the subsequent drying and pyrolysis process materials cannot be in direct contact with hot flue gas to avoid air pollution after discharge.

[0050] After washing, the fly ash can reach a water content of about 30% after filtering through a plate and frame filter press. The material is transported to the rotary cylinder 701 of the indirect heating dryer 7 through a feeding system (which may include a feeding bin, a metering belt, a conveyor belt, a screw conveyor and other devices). A lifting plate is arranged in the rotary cylinder 701, and the rotary cylinder 701 rotates under the action of a power device (a first driving mechanism 710). The lifting plate flips the material and pushes the material forward, so that the material slowly moves to the discharge end. An external heating cover 704 is arranged outside the rotary cylinder 701, and a cavity is formed between the external heating cover 704 and the rotary cylinder 701, and a spiral spacer is arranged in the cavity. The source of hot flue gas is the first combustion chamber 19. A first burner is arranged at the end of the first combustion chamber 19. The combustible gas is ignited by the first burner and burned in the first combustion chamber to provide hot flue gas. The gas outlet end of the first combustion chamber 19 is connected to the air inlet of the external heating cover 704 of the indirect heating dryer 7 through a flange and a pipeline. The air outlet of the external heating cover 704 of the indirect heating dryer 7 is connected to the blower through a flange, a pipe, and the blower. The hot flue gas flows countercurrently along the spiral partition in the external heating cover 704 to indirectly heat the material in the rotating cylinder 701. Since the flue gas does not contact the material, the heated hot flue gas can be directly discharged into the atmosphere through the tail gas pipe under the action of the blower. This process only dries the material, and the temperature of the hot flue gas is controlled between 450-650°C.

[0051] The dried material also needs to be pyrolyzed to remove toxic and harmful substances in the material. After the indirect heating and drying in the previous process, the material is discharged through the discharge end of the indirect heating dryer 7, and then sent to the rotary furnace 2701 of the indirect heating decomposition furnace 27 through the conveying equipment. The equipment structure of the indirect heating decomposition furnace 27 is similar to that of the indirect heating dryer 7. The source of hot flue gas is the second combustion chamber 51. A second burner is arranged at the end of the second combustion chamber 51. The combustible gas is ignited by the second burner and burns in the second combustion chamber to provide hot flue gas. The outlet end of the second combustion chamber 51 is connected to the air inlet of the heat exchange tube cavity 2705 of the indirect heating decomposition furnace 27 through a flange and a pipeline. The outlet end of the heat exchange tube cavity 2705 of the indirect heating decomposition furnace 27 is connected to the blower through a flange, a pipeline. The hot flue gas flows countercurrently along the spiral partition in the heat exchange tube cavity 2705, and indirectly heats the material in the rotary furnace 2701. Since the flue gas does not contact the material, the heated hot flue gas can be directly discharged into the atmosphere through the tail gas pipe under the action of the blower. This process only dries the material, and the temperature of the hot flue gas is controlled between 700-850℃.

[0052] Since the temperature required for pyrolysis of materials is high, the hot flue gas can be used as waste heat after heating. The hot flue gas is transported to the hot flue gas inlet end of the indirect heating dryer 7 through a fan and a pipeline for continued heating, thereby reducing fuel consumption in the drying process.

[0053] In this application, the two combustion chambers for heating flue gas for the indirect heating dryer 7 and the indirect heating decomposition furnace 27 are both independent heating devices outside the rotary equipment. Due to the high temperature of the flue gas, the combustion chamber can be set to a structure of a carbon steel shell plus an insulation layer and a temperature-resistant casting material according to the temperature, or it can be made into a 310s or other high-temperature resistant material as the lining, and the outside is insulated with heat-resistant materials and shells. The external combustion chamber can adjust the temperature as a whole, and then heat the rotary equipment, the temperature is relatively uniform, and the damage to the equipment caused by multi-point direct fire heating is prevented.

[0054] The connecting pipes between the various devices in this application can also be made into a structure of a carbon steel shell plus an insulation layer and a temperature-resistant casting material to reduce the thermal deformation of the pipe and increase the service life of the pipe. In addition, all the equipment in this application is equipped with corresponding instruments and meters for detection, which can be remotely controlled through signal transmission and adjust the flue gas temperature through data feedback to meet production needs.

[0055] In this application, see Figure 1 The rotary drum 701 and the rotary furnace 2701 are both arranged horizontally and tilted along their length direction, and the vertical height of the feed inlet provided thereon is higher than the vertical height of the discharge outlet provided thereon. In addition, the rotary drum 701 and the rotary furnace 2701 are both provided with a turning structure for turning the material and pushing the material forward.

[0056] In one embodiment, see Figure 2 The turning structure in the rotating cylinder 701 includes a plurality of lifting plates arranged on the inner wall of the rotating cylinder 701. The plurality of lifting plates are evenly spaced in the radial direction of the rotating cylinder 701. The length direction of each lifting plate forms an angle with the central axis of the rotating cylinder 701. In another embodiment, see Figure 3 The material turning structure in the rotary drum 701 includes a plurality of material lifting plates arranged on the inner wall of the rotary drum 701. The plurality of material lifting plates form a plurality of material lifting groups on the inner wall of the rotary drum 701. Each material lifting group includes a plurality of material lifting plates evenly spaced along the radial direction of the rotary drum 701. The material lifting plates in two adjacent material lifting groups are staggered. In specific manufacturing applications, the material turning structure in the rotary furnace 2701 can be consistent with the structural form of the material turning structure in the rotary drum 701.

[0057] In the present application, a plurality of spiral baffles are evenly distributed on the inner wall of the external heating cover 704 in a spiral shape, and the spiral baffles are used to spirally guide the hot flue gas introduced from the air inlet to the air outlet, and the air outlet discharges the flue gas after heat exchange to the atmosphere through the first blower. Similarly, a second spiral baffle is provided in the heat exchange tube cavity 2705, and the hot flue gas flows along the second spiral baffle in the heat exchange tube cavity 2705 and exchanges heat with the material in the rotary furnace 2701; a plurality of second spiral baffles are evenly distributed on the inner wall of the heat exchange tube cavity 2705 in a spiral shape, and the spiral baffles are used to spirally guide the hot flue gas introduced from the hot air inlet 2706 to the heat exchange air outlet 2707, and the heat exchange air outlet 2707 discharges the flue gas after heat exchange to the external heating cover 704 of the indirect heating dryer 7 or directly into the atmosphere through the second blower. The spiral baffles can play the role of gas diversion, and the spiral setting can extend the pipe path and the heat exchange time.

[0058] In the present application, a first mounting base 707 is arranged below the rotating cylinder 701, and two first roller supports 708 are arranged oppositely on the first mounting base 707, and a first roller is arranged on the first roller support 708. The rotating cylinder 701 is provided with first support rings 709 for adapting and connecting with the first rollers at both ends along its length direction, and the first support ring 709 is a circle of rolling rings arranged on the outer wall of the rotating cylinder 701, and the rolling rings are fixed on the outer wall of the rotating cylinder through a plurality of connecting seats; a first driving mechanism 710 is also arranged on the first mounting base 707, and the first driving mechanism 710 is used to drive the rotating cylinder 701 to rotate with its central axis as the rotation axis, and the power output shaft of the first driving mechanism 710 is connected to the first driving gear 711, and a circle of first driven gear 712 for adapting and meshing transmission with the first driving gear 711 is arranged on the outer wall of the rotating cylinder 701.

[0059] Similarly, a second mounting base 2711 is arranged below the rotary furnace 2701, and two second roller supports 2712 are arranged oppositely on the second mounting base 2711, and second rollers are arranged on the second roller supports 2712. Second support rings 2713 for adapting and connecting with the second rollers are respectively arranged at both ends of the rotary furnace 2701 along its length direction. The second support ring 2713 is a circle of rolling rings arranged on the outer wall of the rotary furnace 2701, and the rolling rings are fixed on the outer wall of the rotary furnace through a plurality of connecting seats; a second driving mechanism 2714 is also arranged on the second mounting base 2711, and the second driving mechanism 2714 is used to drive the rotary furnace 2701 to rotate with its central axis as the rotation axis, and the power output shaft of the second driving mechanism 2714 is connected to the second driving gear 2715, and a circle of second driven gear 2716 for adapting and meshing transmission with the second driving gear 2715 is arranged on the outer wall of the rotary furnace 2701.

[0060] Therefore, the present application dries and thermally desorbs the fly ash through the indirect heating dryer 7 and the indirect heating decomposition furnace 27. This heating method can be suitable for application scenarios that require that the material cannot be secondary polluted or the flue gas that contacts the material cannot be directly discharged. Indirect heating through the indirect heating dryer 7 and the indirect heating decomposition furnace 27 can avoid the energy loss caused by direct heating and improve thermal efficiency. In addition, since the indirect heating decomposition furnace 27 requires hot flue gas at a higher temperature, and the hot flue gas still has residual heat to be used after heating, the temperature of the hot flue gas required by the indirect heating dryer 7 is relatively low. Therefore, the present device can transport the flue gas discharged from the indirect heating decomposition furnace 27 to the air inlet end of the hot flue gas of the indirect heating dryer 7 through a fan and a pipeline, which is beneficial to the waste heat and the material in the indirect heating dryer 7 for heat exchange and temperature rise, to achieve heat recovery and reuse, reduce the consumption of additional energy, and achieve internal recycling of energy. Therefore, the indirect heating treatment device and treatment process based on high-temperature flue gas provided by the present application can reduce the system's processing energy consumption, improve the efficiency of heat recovery and reuse, and reduce processing costs.

[0061] Embodiment 2

[0062] This embodiment provides an indirect heating process based on high temperature flue gas, using the indirect heating device based on high temperature flue gas provided in the above embodiment 1, see Figure 1 , including the following steps:

[0063] S1: The hot flue gas with a temperature range of 450°C to 650°C in the first combustion chamber 19 is sent to the external heating cover 704 of the indirect heating dryer 7, and the material to be dried is sent to the rotary cylinder 701 of the indirect heating dryer 7. The hot flue gas flows along the spiral diaphragm in the external heating cover 704 and performs countercurrent heat exchange with the material in the rotary cylinder 701. The flue gas that has completed the heat exchange flows into the first blower from the air outlet of the external heating cover 704, and is then discharged to the atmosphere by the first blower. The dried material discharged from the discharge port of the rotary cylinder 701 is sent to the rotary furnace 2701 of the indirect heating decomposition furnace 27;

[0064] S2: The hot flue gas with a temperature range of 700℃~850℃ in the second combustion chamber 51 is sent into the heat exchange tube cavity 2705 of the indirect heating decomposition furnace 27, and the hot flue gas flows along the heat exchange tube cavity 2705 and performs countercurrent heat exchange with the material in the rotary furnace 2701 for thermal desorption. The flue gas that has completed the heat exchange is discharged from the heat exchange air outlet 2707 of the heat exchange tube cavity 2705 to the external heating cover 704 of the indirect heating dryer 7 to heat exchange and heat up the material in the rotary cylinder 701.

[0065] Embodiment 3

[0066] This embodiment is based on the indirect heating treatment device based on high-temperature flue gas provided in the first embodiment, and uses fly ash as the treatment object, and utilizes the indirect heating treatment device to process and utilize the fly ash. In addition to the indirect heating treatment device provided in this application, the fly ash resource treatment process also uses a feeding subsystem and an exhaust gas treatment subsystem, wherein the indirect heating treatment device provided in this application can constitute a drying subsystem and a pyrolysis subsystem. Figures 4 to 6 The processing process of the fly ash resource processing system is described in detail.

[0067] In this embodiment, after passing through the plate and frame filter press (filter pressing and dehydration section), the washed fly ash material with a water content of 30% is delivered to the feeding buffer bin 1 by a forklift. A double-rake extrusion screw 2 is provided at the bottom of the feeding buffer bin 1, and the washed fly ash material is extruded and discharged by the double-rake extrusion screw 2. The lower end of the feeding buffer bin 1 is connected to the metering belt conveyor 3, and the fly ash falls on the metering belt conveyor 3 and is transported to the sealed belt conveyor 4. Through the sealed belt conveyor 4, the material is delivered to the buffer bin of the first screw feeder 6. A screw pusher is provided in the first screw feeder 6. The material is transported to the indirect heating dryer 7 by the screw pusher.

[0068] The indirect heating dryer 7 is an indirect heating rotary body, and a lifting plate is arranged inside the equipment. The function of the lifting plate is to throw the material down when the material rotates to a certain height with the rotary cylinder, so that the material is fully exposed to the radiant heat. The outer heating chamber lining of the indirect heating dryer 7 adopts an aluminum silicate rock wool stacking block structure, which has a small amount of heat storage and heat dissipation, ensuring the heating efficiency, and also plays a heat insulation role to reduce the surface temperature of the equipment.

[0069] In the indirect heating dryer 7, the material moves toward the discharge end under the action of the lifting plate and the rotary motion. In this process, the internal temperature of the indirect heating dryer 7 is about 150°C, the material temperature time is 30-50min, and the moisture of the material is removed to less than 5%. The indirect heating dryer 7 is provided with a discharge port and an air outlet. The dried material is discharged from the discharge port of the indirect heating dryer 7, and a gate valve 8 is provided at the discharge port end, and a discharge valve 9 can also be added here. The discharged material slides to the feed end of the material conveyor (which can be a pipe chain conveyor or a screw conveyor 13). The dried flue gas is discharged from the air outlet of the indirect heating dryer 7 to the air inlet of the first diffusion cyclone separator 10 for gas-solid separation. A discharger (including a gate valve 11 and a discharge valve 12) is provided at the discharge end of the first diffusion cyclone separator 10, and the solid material separated from the first diffusion cyclone separator 10 also enters the feed end of the material conveyor (which can be a pipe chain conveyor or a screw conveyor 13) through the discharger. The separated gas enters the condensation tower 15 for cooling and condensing out the moisture. This process can condense out 85-90% of the moisture in the kiln tail gas, reducing the heat consumption of subsequent combustion. The condensed kiln tail gas is then sent to the cold air side of the second gas-to-gas heat exchanger 37 arranged at the lower side of the outlet end of the calcining furnace 28 for heat exchange. The kiln tail gas after heat exchange is burned in the burner configured at the front end of the combustion chamber 25. The conveying process of the kiln tail gas is all affected by the negative pressure of the induced draft fan arranged at the front end of the burner.

[0070] The hot flue gas of the external heating chamber of the indirect heating dryer 7 is provided by the burner arranged at the front end of the first combustion chamber 19. After the hot flue gas provides heat to the material, it is discharged from the gas outlet end of the external heating chamber of the indirect heating dryer 7. In this embodiment, a first air-to-air heat exchanger 16 can be arranged at the hot flue gas outlet end of the external heating chamber. The hot air side of the first air-to-air heat exchanger 16 is the hot flue gas inlet side, and the hot flue gas outlet side is the first induced draft fan 17. Figure 5 The air outlet of the external heating chamber of the indirect heating dryer 7 is connected to the hot air side inlet and outlet of the first air-to-air heat exchanger 16 and the inlet of the first induced draft fan 17 by pipelines. The hot flue gas after heat exchange is then sent to the exhaust pipe (such as chimney 29) through the first induced draft fan 17 and the pipeline and discharged into the atmosphere.

[0071] Continue to see Figure 5The material conveyed by the screw conveyor 13 arranged below the discharge port of the indirect heating dryer 7 is discharged from the discharge end into the transition bin 21 of the second screw feeder 24 of the pyrolysis system. Specifically, the material conveyed by the screw conveyor 13 is conveyed to the transition bin 21 by the bucket elevator 14 (or directly using a pipe chain conveyor to replace the screw conveyor 13 and the bucket elevator 14 can also achieve the same feeding purpose). The transition bin 21 of the second screw feeder 24 is connected to the upper hopper of the second screw feeder 24, and a spiral pusher is arranged at the lower end of the upper hopper. Under the action of the spiral pusher, the dried material is conveyed to the indirect heating decomposition furnace 27. In specific applications, the equipment used for lifting and transporting materials in this application is not limited to bucket elevators, and other conventional equipment that can play the role of lifting and transporting materials can also be used. Similarly, the equipment used for feeding or conveying materials in this application is not limited to screw feeders, and other conventional equipment that can play the role of feeding and conveying can also be used.

[0072] In this embodiment, the indirect heating decomposition furnace 27 adopts an indirect heating structure, an independent heat source, and an adjustable temperature. The cylinder of the indirect heating decomposition furnace 27 is a rotating body, and a lifting plate is arranged inside. The outer cavity at the end of the discharge direction of the indirect heating decomposition furnace 27 is provided with a cooling section. Natural wind is used to indirectly cool the material, reduce the temperature of the discharged material, and reduce the use of circulating water in the subsequent cooling section. The natural wind here does not contact the material and can be directly discharged into the atmosphere. The equipment adopts fish scale sealing technology to meet the needs of anaerobic pyrolysis. The thermal decomposition temperature of the material is 450-600℃, and the thermal decomposition time is 15-30min. The flue gas emission temperature in the indirect heating decomposition furnace is 450℃. The indirect heating decomposition furnace 27 is provided with a discharge port and an exhaust port. A gate valve 30 is arranged at the discharge port end, and the material after thermal desorption passes through the discharge port and the gate valve 30 and slides into the water-cooled screw conveyor 45 for material cooling. The exhaust port of the indirect heating decomposition furnace 27 is connected to the air inlet of the second diffusion cyclone separator 36 via a pipeline. The discharge end of the second diffusion cyclone separator 36 is connected to the feed end of the water-cooled screw conveyor 45 through the discharger (gate valve 39 and discharge valve 42) and the chute. The gas after thermal desorption enters the second diffusion cyclone separator 36 under the negative pressure of the induced draft fan for gas-solid separation. The separated gas is then sent to the burner configured at the front end of the combustion chamber 25 for combustion. The separated solid enters the feed end of the water-cooled screw conveyor 45 through the discharger and the chute. After thermal utilization, the hot flue gas in the outer cavity of the indirect heating decomposition furnace 27 has a temperature of about 300-400°C, which can be sent to the flue gas inlet of the outer cavity of the indirect heating dryer 7 through the blower 56, and reused as a heating heat source for the indirect heating dryer 7, thereby reducing the heating energy consumption of the system.

[0073] The material after thermal desorption needs to be cooled to 60-80°C. This process uses air cooling and three-stage water cooling to cool the material. Air cooling is the cooling section of the outer cavity of the indirect heating decomposition furnace 27, and the material is cooled indirectly by natural wind. Water cooling uses a three-stage water-cooling conveyor to cool the material. Specifically, the three-stage water-cooling conveyor can include a two-stage water-cooling screw conveyor and a water-cooling pipe chain conveyor. Among them, the inlet of the first-stage water-cooling screw conveyor 45 is connected to the chute of the discharge port of the indirect heating decomposition furnace 27, and the discharge port of the first-stage water-cooling screw conveyor 45 is connected to the inlet of the second-stage water-cooling screw conveyor 48 through the chute. The discharge port of the second-stage water-cooling screw conveyor 48 is connected to the feed port of the water-cooling pipe chain conveyor through the chute. The discharge port of the water-cooling pipe chain conveyor is connected to the feed port of the grinding mill 49 through the chute. The two-stage water-cooling screw conveyor can be placed horizontally or with an inclination of ≤15°. After being cooled by the two-stage water-cooled screw conveyor, the material is lifted from the lower position to the higher position by the water-cooled pipe chain conveyor, discharged from the discharge port at the higher position of the water-cooled pipe chain conveyor, and then transported to the mill 49 through the chute. After being crushed in the mill 49, the material is transported to the finished product warehouse through the pneumatic conveying system and then used in the next process.

[0074] In this embodiment, the kiln tail gas discharged from the indirect heating dryer 7 and the indirect heating decomposition furnace 27 is sent to the calcining furnace 28 for re-combustion and decomposition under the action of the fan. The air inlet end of the calcining furnace 28 of this process is connected to the combustion chamber 25, and a burner is arranged at the end of the combustion chamber 25. The kiln tail gas discharged from the indirect heating dryer 7 and the indirect heating decomposition furnace 27 is transported to the burner for primary wind combustion by the negative pressure of the fan. The combustion temperature is about 1400°C. The outlet temperature of the calcining furnace 28 is above 1100°C. According to the material characteristics, this process requires the flue gas decomposition time to be ≥2s. The calcining furnace 28 is designed as a three-stage, U-shaped structure with a total length of about 30 meters to improve the decomposition rate. Combustible gases, trace organic matter and dioxins are completely decomposed in the calcining furnace 28. Due to the high combustion temperature, the lining of the combustion chamber 25 and the three-stage decomposition furnace are all refractory materials. An SNCR denitrification system is arranged at the top direction of the three-stage decomposition furnace to remove NOx from the flue gas.

[0075] The temperature of the decomposed gas is high and can be used as heat. A second gas-to-gas heat exchanger 37 is provided at the outlet of the calcining furnace 28. The high-temperature flue gas is the hot air side, and the cold air side is divided into three groups, namely natural air, kiln tail gas after condensation of water in the condensation tower 15 in the drying system, and hot air after heat exchange in the drying system. The temperature of the hot air side after heat exchange is 500-550°C, and the temperature of the cold air side is adjusted according to the flow rate required by the burner, and the temperature is between 100-400°C. The wind after heat exchange on the cold side is used as the primary air for burner combustion. After heat exchange, the hot side flue gas enters the quenching device (quenching tower 40). The quenching equipment is arranged below the outlet end of the hot air side of the second gas-to-gas heat exchanger 37. Under the action of the quenching equipment, the flue gas temperature is instantly cooled from 500-550°C to below 220°C. This process prevents the re-generation of dioxins. The cooled exhaust gas is treated by the induced draft fan and then passed through the dust collector (pulse dust collector or bag dust collector 46) for dust removal and then sent to the exhaust gas treatment system for further treatment. The exhaust gas may contain heavy metals. When passing through the entrance of the pulse dust collector, slaked lime, activated carbon powder and flue gas are sprayed in for full mixing to remove more than 60% of the acidic substances and heavy metals in the flue gas, and then the dust is recovered.

[0076] The tail gas treatment system consists of a two-stage alkali washing tower and a water pump. The flue gas after bag dust removal is transported to the first-stage alkali washing tower 23 through the second induced draft fan 55. In the first-stage alkali washing tower 23, the flue gas is neutralized with a 15% NaOH solution to remove some of the acidic substances in the flue gas, and then discharged into the second-stage alkali washing tower 26 to be neutralized with a 15% NaOH solution to remove the remaining acidic substances. The flue gas after two alkali washings is discharged into the atmosphere through the tail gas pipe. All equipment in this system is connected by pipelines. The water pump lifts the NaOH solution at a low place to a high place for spraying. The neutralized saturated brine is discharged to the next process through a pipeline.

[0077] In the fly ash resource processing system, the gas after condensation treatment in the condensation tower 15 can be sent to the second gas-to-gas heat exchanger 37 for heat exchange and temperature increase, and then sent to the burner arranged at the front end of the combustion chamber 25 as the primary air for combustion; the natural air can be heat exchanged and heated by the heat exchange air discharged from the indirect heating dryer 7, and then sent to the second gas-to-gas heat exchanger 37 for secondary heating, and the gas after the secondary heating is used as the primary air for combustion of the indirect heating and heating device of the indirect heating decomposition furnace 27; the indirect heating heat exchange air discharged from the indirect heating decomposition furnace 27 can also be used as the indirect heating hot air of the indirect heating dryer 7, and the natural air that has been heat exchanged and heated by the second gas-to-gas heat exchanger 37 can be sent to the primary air of the burner arranged at the air inlet end of the first combustion chamber 19 that supplies air to the external heating chamber of the indirect heating dryer 7.

[0078] Therefore, the fly ash resource processing system mentioned above dries and thermally desorbs the fly ash through an indirect heating dryer and an indirect heating decomposition furnace, thereby avoiding energy loss caused by direct heating and improving thermal efficiency; the high-temperature gas discharged from the calcining furnace is used for the heat exchange gas supply of other parts through the second gas-to-gas heat exchanger, thereby realizing heat recovery and reuse, reducing the consumption of additional energy, and realizing the internal recycling of energy; the gas discharged from the indirect heating dryer is used for natural wind heating and then heated for a second time through the second gas-to-gas heat exchanger before being reused for indirect heating of the indirect heating decomposition furnace, thereby improving the energy utilization efficiency; in addition, the present application also uses the first and second diffusion cyclone separators to separate the fly ash into gas and solid, The emission of harmful substances is effectively reduced, and the high-temperature calcination of the exhaust gas by the calciner helps to remove harmful substances such as dioxins; the exhaust gas discharged by the calciner is subjected to dust removal and deacidification treatment by a quenching tower, a dust collector and an alkali liquid spray unit, which further reduces the emission of harmful substances and effectively reduces the emission of pollutants in the fly ash treatment process. The fly ash treated as above can be recycled to bring additional economic benefits; therefore, the dry thermal desorption treatment system and treatment process for waste incineration fly ash provided in the present application achieves a dual improvement in the environmental protection and economic benefits of fly ash resource treatment by reducing energy consumption, improving the efficiency of heat recovery and reuse, and effectively treating harmful substances in fly ash.

[0079] The technical features of the above embodiments may be arbitrarily combined (as long as there is no contradiction in the combination of these technical features). To make the description concise, not all possible combinations of the technical features in the above embodiments are described; these embodiments that are not explicitly written should also be considered to be within the scope of this specification.

[0080] The above is a relatively specific and detailed description of the present application through general description and specific embodiments. It should be understood that, based on the technical concept of the present application, several conventional adjustments or further innovations can be made to these specific embodiments; however, as long as they do not deviate from the technical concept of the present application, the technical solutions obtained by these conventional adjustments or further innovations also fall within the scope of protection of the claims of the present application.

Claims

1. An indirect heating treatment device based on high temperature flue gas, characterized in that: It includes a first combustion chamber, a second combustion chamber, an indirect heating dryer and an indirect heating decomposition furnace; The indirect heating dryer comprises a rotating cylinder and an external heating hood arranged on the periphery of the rotating cylinder, an external heating chamber is formed between the rotating cylinder and the external heating hood, a spiral baffle is arranged in the external heating chamber, an air inlet and an air outlet are respectively arranged at two ends of the external heating hood along the length direction thereof, the air inlet is connected to the exhaust end pipe of the first combustion chamber, the hot flue gas exhausted from the first combustion chamber flows along the spiral baffle in the external heating hood and exchanges heat with the material in the rotating cylinder, and the air outlet is connected to the first blower pipe; a material inlet and a material outlet are respectively arranged at two ends of the rotating cylinder along the length direction thereof, the flow direction of the hot flue gas in the external heating chamber is opposite to the flow direction of the material passed into the rotating cylinder, and a material turning structure for turning the material and pushing the material forward is arranged in the rotating cylinder; The indirect heating decomposition furnace includes a rotary furnace and a heat exchange tube cavity arranged outside the rotary furnace, the rotary furnace is provided with a feed port, a discharge port and an exhaust port, the feed port of the rotary furnace is connected with the discharge port of the rotary cylinder, a hot air inlet and a heat exchange air outlet are respectively arranged at both ends of the heat exchange tube cavity, the hot air inlet is connected with the flue gas outlet of the second combustion chamber, the heat exchange air outlet is connected with the air inlet of the external heating cover, and the flow direction of the hot flue gas in the heat exchange tube cavity is opposite to the flow direction of the material in the rotary furnace.

2. The indirect heating treatment device based on high temperature flue gas according to claim 1, characterized in that: The rotary cylinder is arranged horizontally and tilted along its length direction, and the vertical height of the feed port on the rotary cylinder is higher than the vertical height of the discharge port arranged thereon; The rotary furnace is arranged horizontally and tilted along its length direction, and the vertical height of the feed port on the rotary furnace is higher than the vertical height of the discharge port arranged thereon; A material turning structure for turning materials and pushing the materials forward is arranged in the rotary furnace.

3. The indirect heating treatment device based on high temperature flue gas according to claim 1, characterized in that: A first mounting base is arranged below the rotating cylinder, two first roller supports are arranged opposite to each other on the first mounting base, a first roller is arranged on the first roller support, and first support rings for adapting and connecting with the first rollers are respectively arranged at both ends of the rotating cylinder along its length direction, the first support ring is a rolling ring arranged on the outer wall of the rotating cylinder, and the rolling ring is fixed to the outer wall of the rotating cylinder through a plurality of connecting seats; A first driving mechanism is also provided on the first mounting base. The first driving mechanism is used to drive the rotating cylinder to rotate with its central axis as the rotation axis. The power output shaft of the first driving mechanism is connected to the first driving gear. A first driven gear that is adapted to mesh with the first driving gear is provided on the outer wall of the rotating cylinder.

4. The indirect heating treatment device based on high temperature flue gas according to claim 1, characterized in that: A second mounting base is arranged below the rotary furnace, two second roller supports are arranged opposite to each other on the second mounting base, second rollers are arranged on the second roller supports, and second support rings for adapting and connecting with the second rollers are respectively arranged at both ends of the rotary furnace along its length direction, and the second support ring is a rolling ring arranged on the outer wall of the rotary furnace, and the rolling ring is fixed to the outer wall of the rotary furnace through a plurality of connecting seats; A second driving mechanism is also provided on the second mounting base, and the second driving mechanism is used to drive the rotary furnace to rotate with its central axis as the rotation axis. The power output shaft of the second driving mechanism is connected to the second driving gear, and a second driven gear is provided on the outer wall of the rotary furnace for meshing transmission with the second driving gear.

5. The indirect heating treatment device based on high temperature flue gas according to claim 2, characterized in that: A plurality of spiral spacers are evenly distributed on the inner wall of the outer heating cover in a spiral shape, and the spiral spacers are used to spirally guide the hot flue gas introduced from the air inlet to the air outlet, and the air outlet discharges the flue gas after heat exchange to the atmosphere through the first blower, and the temperature range of the hot flue gas introduced into the air inlet is 450°C to 650°C; A second spiral baffle is provided in the heat exchange tube cavity, and the hot flue gas flows along the second spiral baffle in the heat exchange tube cavity and exchanges heat with the material in the rotary furnace; a plurality of the second spiral baffles are evenly distributed on the inner wall of the heat exchange tube cavity in a spiral shape, and the spiral baffle is used to spirally guide the hot flue gas introduced from the hot air inlet to the heat exchange air outlet, and the heat exchange air outlet discharges the heat-exchanged flue gas to the external heating cover of the indirect heating dryer or directly into the atmosphere through the second air supply fan; the temperature range of the hot flue gas introduced into the hot air inlet is 700°C to 850°C.

6. The indirect heating treatment device based on high temperature flue gas according to claim 1, characterized in that: The material turning structure inside the rotating cylinder includes a plurality of material lifting plates arranged on the inner wall of the rotating cylinder, the plurality of material lifting plates are evenly spaced in the radial direction of the rotating cylinder, and the length direction of each material lifting plate forms an angle with the central axis of the rotating cylinder; or, the plurality of material lifting plates form a plurality of material lifting groups on the inner wall of the rotating cylinder, each of the material lifting groups includes a plurality of material lifting plates evenly spaced in the radial direction of the rotating cylinder, and the material lifting plates in two adjacent material lifting groups are staggered.

7. The indirect heating treatment device based on high temperature flue gas according to claim 2, characterized in that: The material turning structure in the rotary furnace includes a plurality of material lifting plates arranged on the inner wall of the rotary furnace, and the plurality of material lifting plates are evenly spaced in the radial direction of the rotary furnace, and the length direction of each material lifting plate forms an angle with the central axis of the rotary furnace; or, the plurality of material lifting plates form a plurality of material lifting groups on the inner wall of the rotary furnace, and each of the material lifting groups includes a plurality of material lifting plates evenly spaced in the radial direction of the rotary furnace, and the material lifting plates in two adjacent material lifting groups are staggered.

8. The indirect heating treatment device based on high temperature flue gas according to claim 1, characterized in that: The discharge port of the rotary cylinder is connected to a material conveying device, and the material conveying device is used to convey the dried material discharged from the rotary cylinder to the indirect heating decomposition furnace; The rotary furnace is also provided with an air cooling tube cavity, the heat exchange tube cavity and the air cooling tube cavity are adjacently arranged on the rotary furnace, the heat exchange tube cavity is close to the feed port of the rotary furnace, and the air cooling tube cavity is close to the discharge port of the rotary furnace; The heat exchange tube cavity is used for thermally desorbing the fly ash sent into the rotary furnace, so that the fly ash decomposes into harmful gases, and the harmful gases enter the calcining furnace from the exhaust port of the rotary furnace; the two ends of the air cooling tube cavity are respectively provided with a cold air inlet and a heat exchange cold air outlet; the air cooling tube cavity is used for cooling the fly ash after thermal desorption.

9. The indirect heating treatment device based on high temperature flue gas according to claim 1, characterized in that: A first burner is disposed at the end of the first combustion chamber, and the first burner is used to ignite the combustible gas introduced into the first combustion chamber to generate hot flue gas; A second burner is disposed at the end of the second combustion chamber, and the second burner is used to ignite the combustible gas introduced into the second combustion chamber to generate hot flue gas; The outer shells of the first combustion chamber and the second combustion chamber are both made of carbon steel, and the interiors of the first combustion chamber and the second combustion chamber are both provided with a thermal insulation layer and a high temperature resistant casting material; The connecting pipe between the first combustion chamber and the indirect heating dryer is a carbon steel pipe with an internal insulation layer and high temperature resistant casting material; The connecting pipeline between the second combustion chamber and the indirect heating decomposition furnace is a carbon steel pipeline with an internal insulation layer and high-temperature resistant casting material.

10. An indirect heating process based on high temperature flue gas, characterized in that: The indirect heating treatment device based on high temperature flue gas according to claim 1 comprises the following steps: S1: sending the hot flue gas with a temperature range of 450°C to 650°C in the first combustion chamber into the external heating cover of the indirect heating dryer, and sending the material to be dried into the rotary cylinder of the indirect heating dryer, the hot flue gas flows along the spiral baffle in the external heating cover and performs countercurrent heat exchange with the material in the rotary cylinder, the flue gas that has completed the heat exchange flows into the first blower from the air outlet of the external heating cover, and is then discharged to the atmosphere by the first blower, and the dried material discharged from the discharge port of the rotary cylinder is sent to the rotary hearth of the indirect heating decomposition furnace; S2: The hot flue gas with a temperature range of 700℃~850℃ in the second combustion chamber is sent into the heat exchange tube cavity of the indirect heating decomposition furnace, the hot flue gas flows along the heat exchange tube cavity and performs countercurrent heat exchange with the material in the rotary furnace for thermal desorption, and the flue gas that has completed the heat exchange is discharged from the heat exchange air outlet of the heat exchange tube cavity to the external heating cover of the indirect heating dryer to heat exchange and heat up the material in the rotary cylinder.

Images