Coal-based belt type roasting system

Abstract

The utility model discloses a coal-based belt type roasting system, which is characterized in that a coal injection flame-retardant section is additionally arranged after roasting and before cooling to spray pulverized coal and flame retardant, so that the pulverized coal is preheated while high-temperature materials after roasting are primarily cooled; gradient cooling of high-temperature materials is achieved, the quality of roasted products is guaranteed, meanwhile, the temperature of secondary hot air can be further improved, and the stability of the materials in the roasting process is guaranteed; cheap pulverized coal can be used as heat supply fuel for the belt type roasting device, the belt type roasting device has the advantage of being low in production cost, the application range of an existing belt type roasting device is greatly widened, a new development direction is provided for the belt type roasting process in steel pellet production, and the production cost is reduced. And the method has remarkable social and economic benefits and excellent prospects of large-scale popularization, implementation and application.

Description

Technical Field

[0001] The utility model relates to steel metallurgy production equipment, in particular to a coal-based belt roasting system, belonging to the technical field of steel metallurgy production. Background Technique

[0002] Oxidized pellets are an important type of furnace charge for blast furnace smelting. At present, the processes for producing oxidized pellets on the market mainly include three categories: the grate-kiln process, the traveling grate-roaster process, and the shaft furnace pelletizing process. Among them, the shaft furnace pelletizing process has been gradually phased out, with a market share of less than 5%. The traveling grate-roaster process is favored in the industry due to its advantages such as small floor area, good equipment integrity, and advanced energy consumption and emission indicators, and has become the mainstream of the future pellet market.

[0003] In the current trend of the steel market, vigorously developing low-cost pelletizing processes is the key to the future upgrading and transformation of the steel industry. At present, as the mainstream pellet process, the traveling grate-roaster is limited by equipment technology and can only use high-calorific-value gas (natural gas or coke oven gas) as fuel, and pulverized coal cannot be selected, resulting in the following problems: 1) High process cost: Since the traveling grate-roaster process currently must use high-calorific-value gas, and the price of this part of high-calorific-value gas is very high, the process cost of producing pellets by the entire traveling grate-roaster remains high; 2) Limited process suitability: It is uneconomical and unrealistic for many steel enterprises to spend a high price to introduce a gas pipeline specifically for building a traveling grate-roaster pellet production line, which leads to many steel enterprises being unable to choose the traveling grate-roaster process. Content of the Utility Model

[0004] Aiming at the problems of high production cost and limited application existing in the existing traveling grate-roasting process using high-calorific-value gas as fuel in the prior art, the utility model provides a coal-based belt roasting system. By adding a pulverized coal spraying and flame retardant section between the roasting section and the cooling section of the belt roasting device, on the one hand, spraying pulverized coal and flame retardant can not only preliminarily cool the high-temperature materials after roasting but also preheat the pulverized coal, which is beneficial to the subsequent ignition of the pulverized coal and the gradient cooling of the high-temperature materials after roasting, improving the quality of the roasted products; on the other hand, the sprayed pulverized coal will be ignited by the ignition mechanism in the secondary air duct along with the hot air generated during the cooling process in the cooling section and release heat to further increase the temperature of the secondary hot air, which is beneficial to ensuring the stability of the material roasting process; that is to say, the utility model can use cheap pulverized coal as the heating fuel for the belt roasting device, has the advantage of low production cost, greatly expands the application range of the existing belt roasting device, provides a new development direction for the traveling grate-roasting process in steel pellet production, and has significant social and economic benefits and excellent prospects for large-scale popularization and implementation.

[0005] To achieve the above technical objectives, the technical solutions adopted by the utility model are described as follows:[[]]

[0006] A coal-based belt roasting system. According to the material flow direction, the system includes a drum drying section, a suction drying section, a preheating section, a roasting section, a coal spraying and flame retardant section, a first cooling section, a second cooling section, and a hot air hood covering each section. The top air outlet of the first cooling section is connected to the air inlet of the hot air hood above the roasting section through a secondary air duct. A spraying mechanism is provided on the coal spraying and flame retardant section. An ignition mechanism is provided in the secondary air duct.

[0007] Preferably, cold air ducts are connected to the bottom air inlets of both the first cooling section and the second cooling section. A first hot air circulation pipeline is also led out from the secondary air duct and connected to the top air inlet of the preheating section. The top air outlet of the second cooling section is connected to the bottom air inlet of the drum drying section through a second hot air circulation pipeline. The bottom air outlet of the roasting section is connected to the top air inlet of the suction drying section through a third hot air circulation pipeline. The top air outlets of the drum drying section, the bottom air outlets of the suction drying section, and the bottom air outlets of the preheating section are all connected to external exhaust air ducts.

[0008] Preferably, the spraying mechanism includes a mobile coal powder conveyor and a flame retardant side spray pipe. An opening is provided at the top of the hot air hood above the coal spraying and flame retardant section, and the mobile coal powder conveyor is movably arranged above the opening. The flame retardant side spray pipe is arranged on the side wall of the hot air hood above the coal spraying and flame retardant section.

[0009] Preferably, the spraying mechanism includes a coal powder top spray pipe and a flame retardant top spray pipe. The coal powder top spray pipe and the flame retardant top spray pipe are both arranged in the hot air hood and above the material layer of the coal spraying and flame retardant section, and the coal powder top spray pipe is directly above the flame retardant top spray pipe.

[0010] Preferably, the spraying mechanism includes a coal powder inner cylinder spray pipe and a flame retardant outer cylinder spray pipe. The flame retardant outer cylinder spray pipe is arranged at the top of the hot air hood above the coal spraying and flame retardant section. The coal powder inner cylinder spray pipe is sleeved inside the flame retardant outer cylinder spray pipe. The bottom ends of both the coal powder inner cylinder spray pipe and the flame retardant outer cylinder spray pipe penetrate through the top of the hot air hood and extend into the hot air hood, and the bottom end of the flame retardant outer cylinder spray pipe is lower than the bottom end of the coal powder inner cylinder spray pipe. Preferably, a swirl stirrer is also provided inside the flame retardant outer cylinder spray pipe below the bottom end of the coal powder inner cylinder spray pipe.

[0011] Preferably, the ignition mechanism is an arc heating electrode, including an arc positive electrode rod and an arc negative electrode rod, which are oppositely arranged on the pipe wall of the secondary air duct.

[0012] Preferably, multiple pairs of arc positive electrode rods and arc negative electrode rods are arranged along the circumferential direction of the pipe wall of the secondary air duct and / or multiple pairs of arc positive electrode rods and arc negative electrode rods are arranged in the axial direction of the secondary air duct.

[0013] Preferably, the secondary air duct is connected to the side air inlets of the hot air hood above the roasting section through multiple secondary air branch pipes. The lower pipe section of the secondary air branch pipe is bent upward and then forms a bent air outlet pipe section, that is, the air outlet end of the bent air outlet pipe section is communicated with the side air inlets of the hot air hood.

[0014] Preferably, a weighing ash hopper is communicatively arranged at the lowest end of the bent air outlet pipe section. A bearing ear plate extends horizontally outward from the upper hopper wall of the weighing ash hopper, and the bearing ear plate is connected to the pipe wall on the lower side of the lowest end of the bent air outlet pipe section through a weighing spring.

[0015] Preferably, a plurality of telescopic baffles are also arranged in the bent air outlet pipe section. Along the axial direction of the bent air outlet pipe section, the plurality of telescopic baffles are respectively arranged vertically on the inner wall of the pipe cavity of the bent air outlet pipe section in a relatively staggered manner through a plurality of telescopic driving motors.

[0016] Preferably, a steam injection mechanism is also arranged at the bottom of the first cooling section. The steam injection mechanism includes a steam main pipe and steam branch pipes. Steam main pipes are arranged on both sides of the air box at the bottom of the first cooling section, and each steam main pipe is communicated with the inside of the air box at the bottom of the first cooling section through a plurality of steam branch pipes.

[0017] Preferably, a number of temperature measuring elements are also arranged in the hot air hood above the roasting section.

[0018] In the present utility model, a section for coupling and injecting pulverized coal and a flame retardant is added between the roasting section and the cooling section of the belt roasting device. In this section, the pulverized coal and the flame retardant are coupled and injected, so that the pulverized coal is laid on the surface of the material layer in an unburned state. When the material layer moves with the trolley into the first stage of cooling, the pulverized coal can be carried away by the cooling air passing through the material layer, enter the main secondary air duct, and be ignited by the ignition mechanism arranged in the secondary air duct for combustion. By injecting pulverized coal after roasting and before cooling, on the one hand, the pulverized coal can play a role in initially cooling the high-temperature material after roasting through contact heat exchange, and combined with the subsequent two-stage air cooling, gradient cooling of the high-temperature material after roasting can be achieved, which helps to improve the quality of the roasted product; on the other hand, the pulverized coal can absorb the sensible heat of the material after roasting to realize preheating (facilitating subsequent ignition). At the same time, under the protection of the flame retardant (such as nitrogen), the pulverized coal will not burn. When the pulverized coal enters the first stage of cooling with the material layer, it will be carried into the secondary air duct by the hot air generated during the cooling process and be ignited by the ignition mechanism to release heat, thereby significantly increasing the temperature of the secondary hot air and ensuring the stability of the material roasting process. The cooling air for cooling the roasted material is blown in by a fan, exchanges heat with the high-temperature material in the cooling section, and the hot air after heat exchange enters the roasting section through the secondary air inlet mechanism (secondary air duct and secondary air branch pipe) arranged above the roasting section to act as combustion-supporting air for the roasting heating system; during this process, according to the actual working conditions, by adjusting the injection amount of pulverized coal into the pulverized coal injection and flame retardant section, the heating effect on the hot air can be realized, so that the temperature of the secondary hot air finally entering the roasting section meets the roasting requirements, that is, by using the existing structure of the belt roasting device as the injection and combustion site of the pulverized coal, the pulverized coal can replace high-quality gas as the roasting heating fuel, without additional installation of a combustion chamber or additional occupation of space, significantly reducing the production cost. Moreover, compared with high-quality gas with high price and inconvenient transportation, the pulverized coal has the advantages of wider distribution, easier source acquisition and transportation, etc., and has stronger practicability and economy; that is to say, the present utility model can achieve a breakthrough in replacing expensive gas with cheap pulverized coal as the roasting heating fuel without reducing the quality of the roasted product, overcome the deficiencies of the existing belt roasting device with high process cost and limited process suitability, and provide a new development path for the belt roasting process in iron and steel pellet production.

[0019] In the present utility model, a material spraying mechanism is provided on the pulverized coal flame-retardant section. The present utility model has developed various material spraying mechanisms for coupling and spraying pulverized coal and flame retardant. The material spraying mechanism includes a mobile pulverized coal conveyor (such as a mobile belt conveyor) and a side spraying pipe for flame retardant. The side spraying pipe for flame retardant is installed on the side of the hot air hood body and can spray flame-retardant gases such as nitrogen and argon into the hood. At the same time, the mobile pulverized coal conveyor is installed on the top of the hood body and can evenly and reciprocally spray pulverized coal on the surface of the material layer. Alternatively, the material spraying mechanism includes a top spraying pipe for pulverized coal and a top spraying pipe for flame retardant. The top spraying pipe for flame retardant is installed above the material layer inside the hot air hood body, and the top spraying pipe for pulverized coal is installed directly above the top spraying pipe for flame retardant. When both are opened simultaneously, the pulverized coal can be sprayed on the surface of the material layer in an unburned state. Or the material spraying mechanism includes an inner cylinder spraying pipe for pulverized coal and an outer cylinder spraying pipe for flame retardant. The outer cylinder spraying pipe for flame retardant includes the inner cylinder spraying pipe for pulverized coal, and a swirl stirrer is provided at the end where the flame retardant and pulverized coal are ejected. After the pulverized coal and the flame retardant are evenly stirred by the swirl, they are sprayed onto the surface of the lower material layer. That is to say, the material spraying mechanisms of the present utility model are all structurally designed to evenly spray pulverized coal onto the surface of the material layer in a flame-retardant state, which helps the uniform contact heat transfer between the pulverized coal and the material layer. It should be noted that the concentration of the gas flame retardant is relatively high in the pulverized coal flame-retardant section, so it can prevent the pulverized coal from spontaneous combustion due to heat. After it enters the secondary air duct with the pulverized coal, since it is diluted by a large amount of secondary air and the secondary air contains abundant oxygen, the pulverized coal can be ignited by the ignition mechanism in the secondary air duct.

[0020] In the present utility model, an ignition mechanism composed of an arc positive electrode rod and an arc negative electrode rod is added to the pipeline of the secondary air duct. The mixed and uniform coal-air mixture is heated and ignited by this ignition mechanism, so that the pulverized coal can be quickly burned out in the secondary air duct, thereby significantly increasing the temperature of the secondary hot air and ensuring the uniformity of the temperature in the roasting section, which helps to improve and guarantee the quality of the roasted product. In a preferred embodiment, the heating and ignition device specifically includes a plurality of pairs of alternating current arc electrodes (composed of an arc positive electrode rod and an arc negative electrode rod) symmetrically arranged in a certain length of the pipe section of the secondary air duct. Its function is to form a breakdown arc between the positive and negative electrode rods to form a local high temperature, thereby igniting the pulverized coal flow passing between the electrode rods, so that the pulverized coal can burn quickly while flowing in the secondary air duct.

[0021] In the present utility model, the secondary air duct is connected to the side air inlets of the hot air hood above the roasting section through multiple secondary air branch pipes. The lower pipe section of the secondary air branch pipe is an upwardly inclined and bent pipe section, which forms a bent outlet air duct section. By adding a weighing ash hopper in the bent outlet air duct section (to prevent pulverized coal from entering the roasted material layer, and since the silicon content of the coal ash is relatively high, it is easy to cause the bonding of pellet ore), the weighing ash hopper is fixed below the pipe wall at the lowest end of the bent outlet air duct section through a bearing ear plate and a weighing spring. The purpose is to accumulate and weigh the coal ash after the pulverized coal in the secondary air duct is completely burned under the action of gravity, so as to judge whether there is coal ash entering the hot air hood in the roasting section or whether there is an abnormal condition where the pulverized coal is not completely burned. It should be noted that the weighing spring is a weighing spring with an elastic sealing air curtain. The material of the elastic sealing air curtain can be any non-venting soft material and does not affect the expansion and contraction of the spring. Its main function is to ensure airtightness and prevent air leakage.

[0022] In the present utility model, the bent outlet air duct section of the secondary air branch pipe is an inclined design with the air inlet end lower than the air outlet end. Multiple telescopic baffles are also arranged in the bent outlet air duct section. The multiple telescopic baffles are respectively arranged vertically on the inner wall of the pipe cavity of the bent outlet air duct section in a relatively staggered manner through multiple telescopic drive motors. The purpose is to block the pulverized coal and coal ash carried in the secondary hot air reaching the bottom and continuing to flow to the roasting section through the bent outlet air duct section under the action of the baffles, and make the blocked pulverized coal and coal ash settle to the weighing ash hopper below it under the action of natural gravity.

[0023] In the present utility model, several temperature measuring elements are also arranged in the hot air hood above the roasting section. The purpose is to infer whether the temperature in the roasting chamber is uniform through element temperature measurement, and further infer whether unburned pulverized coal has entered the roasting chamber and continued to burn.

[0024] In the present utility model, a steam injection mechanism is added on both sides of the bottom air box in the first cooling section of the present utility model, which consists of a steam main pipe and steam branch pipes. Its function is to inject steam into the bottom air box of the first cooling section of the belt grate cooler, mix it with air, and finally spray it out from the material surface. In this way, the pulverized coal sprayed on the material surface at the front end can move up and down suspended under the action of the wind, and react with the steam therein to generate combustible gas, which enters the secondary air duct and is finally ignited by the arc electrode to form qualified high-temperature secondary hot air suitable for pellet roasting.

[0025] In the present utility model, according to the material flow direction, the material to be processed undergoes drying, preheating, roasting, and cooling processes in sequence to obtain the finished material. During this process, according to the actual working conditions, the pulverized coal amount sprayed onto the material layer after roasting and before cooling is controlled by the spraying mechanism to ensure the stable operation of the system. Specifically: the system will first detect multiple working condition parameters in the current working conditions (including pellet quality, required roasting temperature, pulverized coal calorific value, etc.), and calculate the pulverized coal injection value. For example, if the pulverized coal amount injected through the spraying mechanism per unit time is set as W mf , Kg: then there is:

[0026] W mf =W qt ×C qt ×(T 1 -T 0 )÷Q mf (1)

[0027] In formula (1), W qt is the pellet mass undergoing roasting treatment per unit time, Kg. C qt is the specific heat capacity of the pellet, KJ / (kg·°C). T 1 is the target temperature to which the pellet needs to be heated during roasting treatment, °C. T 0 is the initial temperature of the pellet during roasting treatment, °C. Q mf is the calorific value of the pulverized coal, KJ / Kg.

[0028] Furthermore, when the pulverized coal amount injected through the spraying mechanism per unit time is W mf : the system automatically controls the opening degree of the pulverized coal injection valve according to this calculated value. At the same time, according to the pulverized coal injection value, the pipe section length range of the ignition arc area in the secondary air duct and the coal ash generation value, etc. are calculated. For example, if the pipe section length for the ignition mechanism to heat the secondary air duct is set as L, m. The generated mass of coal ash is W mh , Kg. Then there is:

[0029] L = W mf ×λ×V×d (2)

[0030] W mh =W mf ×η (3)

[0031] In formulas (2)-(3), λ is the length correction coefficient, with a value range of 7.8 - 14.1 (preferably 8.3 - 13.0). V is the flow velocity of the combustion-supporting air, m / s. d is the particle size of the pulverized coal, m. η is the coal ash generation coefficient, with a value range of 0.005 - 0.05.

[0032] It should be noted that the system activates the corresponding arc elements according to the calculation results of formulas (2)-(3). For example, if the calculated pipe section length L requires activating 8 pairs of AC arc electrodes, then 8 pairs of AC arc electrodes will be activated. After that, the system will detect whether the weight of the coal ash measured in the weighing hopper is equal to the calculated coal ash generation value W mh If they are equal, this adjustment ends. If not, it enters the feedback adjustment link. In the feedback adjustment link, the system will detect whether the temperature values at different positions in the hot air hood of the roasting section are uniform through several temperature measuring elements set in the hot air hood above the roasting section: If so, it indicates that the pulverized coal has been burned out in the secondary air pipe, but the coal ash has entered the roasting section. At this time, the system will send a signal to the labyrinth partition mechanism (composed of multiple telescopic baffles and multiple telescopic drive motors) to increase the insertion depth of the baffles and reduce the possibility of pulverized coal being carried into the roasting section by the secondary hot air; If the temperature is not uniform, it indicates that the pulverized coal has not been burned out in the secondary air pipe and there is still secondary combustion after entering the roasting section. At this time, the system will send a signal to the ignition mechanism to extend the distance range of the ignition arc area on the secondary air pipe (i.e., increase the number of pairs of AC arc electrodes turned on). After this operation, the system will continue to detect the weight of the ash powder in the weighing hopper and compare it with the calculated coal ash generation value. If they are still not equal, the steps of this link will be repeated until they are equal. If they are equal, the system defaults that this adjustment ends.

[0033] It should be noted that all the formulas in the present invention are obtained by the inventor through fitting based on experiments and engineering applications. All calculations are based on the values after conversion according to the specified unit conversions. The values after converting the units are substituted into the formulas for calculation (after converting the units, only the values are substituted into the formulas for calculation, without substituting the units. The units are only used to adjust the magnitudes of the values).

[0034] In the present invention, the system of the present invention has a function associated with an external automatic control and adjustment mechanism, and realizes the automatic and precise control and adjustment of the system through the automatic control and adjustment mechanism, thereby ensuring the stability and safety of the system operation.

[0035] In the present invention, in the preferred implementation, the diameter of the secondary air pipe is 5 - 300 cm, preferably 8 - 200 cm, and more preferably 10 - 100 cm. The diameter of the secondary air branch pipe is 1 - 200 cm, preferably 3 - 150 cm, and more preferably 5 - 80 cm. The length of the coal injection flame retardant section is 0.3 - 10 m, preferably 0.8 - 8 m, and more preferably 1 - 5 m. The thickness of the hot air hood is 0.1 - 80 cm, preferably 0.5 - 50 cm, and more preferably 1 - 30 cm.

[0036] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0037] 1: By spraying pulverized coal and flame retardant on the material layer after roasting and before cooling, the present utility model not only preliminarily cools the high-temperature material after roasting but also preheats the pulverized coal; the heat exchange of the pulverized coal and the subsequent two-stage air-cooling heat exchange achieve the gradient cooling of the high-temperature material, which is beneficial to ensuring the quality of the roasted product; the preheated pulverized coal is ignited in the secondary air duct and releases heat, which can further increase the temperature of the secondary hot air and is conducive to ensuring the stability of the material roasting process; that is, the present utility model can use cheap pulverized coal as a heating fuel for the belt roasting device, has the advantage of low production cost, greatly expands the application range of the existing belt roasting device, provides a new development direction for the belt roasting process in iron and steel pellet production, has significant social and economic benefits, and has an excellent prospect for large-scale popularization and implementation.

[0038] 2: The implementation of the present utility model does not require additional site occupation, and has low investment and operation costs. The overall structure is simple, and the operation is stable and reliable, having excellent practical application value in the future market. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic structural diagram of the belt roasting system described in the present utility model.

[0040] Figure 2 It is a partial enlarged schematic diagram of the roasting section, pulverized coal spraying and flame retardant section, and the first cooling section of the system described in the present utility model.

[0041] Figure 3 It is a schematic cross-sectional structure diagram of the system described in the present utility model.

[0042] Figure 4 It is a schematic structural diagram of the present utility model when the spraying mechanism is a mobile pulverized coal conveyor and a side spraying pipe for flame retardant.

[0043] Figure 5 It is a schematic structural diagram of the present utility model when the spraying mechanism is a top spraying pipe for pulverized coal and a top spraying pipe for flame retardant.

[0044] Figure 6 It is a schematic structural diagram of the present utility model when the spraying mechanism is an inner cylinder spraying pipe for pulverized coal and an outer cylinder spraying pipe for flame retardant.

[0045] Figure 7 It is a schematic connection structure diagram of the weighing ash hopper, load-bearing ear plates, and weighing springs of the present utility model.

[0046] Figure 8 It is a schematic top view structure diagram of the present utility model when a main steam pipe and a branch steam pipe are provided in the first cooling section.

[0047] Figure 9 It is a schematic connection structure diagram of the telescopic partition board and the telescopic drive motor of the present utility model.

[0048] Reference numerals: 1: drum drying section; 2: draining section; 3: preheating section; 4: roasting section; 401: third hot air circulation pipe; 402: temperature measuring element; 5: coal injection and flame retardant section; 6: first cooling section; 601: main steam pipe; 602: steam branch pipe; 7: second cooling section; 701: second hot air circulation pipe; 8: hot air hood; 9: spraying mechanism; 901: mobile coal powder conveyor; 902: side spray pipe for flame retardant; 903: top spray pipe for coal powder; 904: top spray pipe for flame retardant; 905: inner cylinder spray pipe for coal powder; 906: outer cylinder spray pipe for flame retardant; 907: swirl stirrer; 10: ignition mechanism; 1001: arc positive electrode rod; 1002: arc negative electrode rod; 11: secondary air duct; 1101: first hot air circulation pipe; 12: secondary air branch pipe; 13: weighing ash hopper; 14: bearing ear plate; 15: weighing spring; 16: telescopic baffle; 17: telescopic drive motor. Detailed implementation manners

[0049] The technical solutions of the present utility model will be illustrated below. The scope of protection claimed by the present utility model includes but is not limited to the following embodiments.

[0050] A coal-based belt roasting system. According to the material flow direction, the system includes a drum drying section 1, a draining section 2, a preheating section 3, a roasting section 4, a coal injection and flame retardant section 5, a first cooling section 6, a second cooling section 7, and a hot air hood 8 covering above each section in series. The top air outlet of the first cooling section 6 is connected to the air inlet of the hot air hood 8 above the roasting section 4 through a secondary air duct 11. A spraying mechanism 9 is provided on the coal injection and flame retardant section 5. An ignition mechanism 10 is provided in the secondary air duct 11.

[0051] Preferably, cold air ducts are connected to the bottom air inlets of both the first cooling section 6 and the second cooling section 7. A first hot air circulation pipe 1101 is also led out from the secondary air duct 11 and connected to the top air inlet of the preheating section 3; the top air outlet of the second cooling section 7 is connected to the bottom air inlet of the drum drying section 1 through a second hot air circulation pipe 701. The bottom air outlet of the roasting section 4 is connected to the top air inlet of the draining section 2 through a third hot air circulation pipe 401. The top air outlets of the drum drying section 1, the bottom air outlets of the draining section 2, and the bottom air outlets of the preheating section 3 are all connected with outer exhaust air ducts.

[0052] Preferably, the spraying mechanism 9 includes a mobile coal powder conveyor 901 and a side spray pipe 902 for flame retardant. An opening is provided at the top of the hot air hood 8 above the coal injection and flame retardant section 5, and the mobile coal powder conveyor 901 is movably arranged above the opening. The side spray pipe 902 for flame retardant is arranged on the side wall of the hot air hood 8 above the coal injection and flame retardant section 5.

[0053] Preferably, the material spraying mechanism 9 includes a pulverized coal top spraying pipe 903 and a flame retardant top spraying pipe 904. The pulverized coal top spraying pipe 903 and the flame retardant top spraying pipe 904 are both arranged in the hot air hood 8 and above the material layer in the coal spraying and flame retardant section 5, wherein the pulverized coal top spraying pipe 903 is directly above the flame retardant top spraying pipe 904.

[0054] Preferably, the material spraying mechanism 9 includes a pulverized coal inner cylinder spraying pipe 905 and a flame retardant outer cylinder spraying pipe 906. The flame retardant outer cylinder spraying pipe 906 is arranged at the top of the hot air hood 8 above the coal spraying and flame retardant section 5. The pulverized coal inner cylinder spraying pipe 905 is sleeved inside the flame retardant outer cylinder spraying pipe 906. The bottom ends of the pulverized coal inner cylinder spraying pipe 905 and the flame retardant outer cylinder spraying pipe 906 both penetrate through the top of the hot air hood 8 and extend into the hot air hood 8, and the bottom end of the flame retardant outer cylinder spraying pipe 906 is lower than the bottom end of the pulverized coal inner cylinder spraying pipe 905. Preferably, a swirl stirrer 907 is further arranged inside the flame retardant outer cylinder spraying pipe 906 below the bottom end of the pulverized coal inner cylinder spraying pipe 905.

[0055] Preferably, the ignition mechanism 10 is an arc heating electrode, including an arc positive electrode rod 1001 and an arc negative electrode rod 1002, and the arc positive electrode rod 1001 and the arc negative electrode rod 1002 are oppositely arranged on the pipe wall of the secondary air pipe 11.

[0056] Preferably, multiple pairs of arc positive electrode rods 1001 and arc negative electrode rods 1002 are arranged along the circumferential direction of the pipe wall of the secondary air pipe 11 and / or multiple pairs of arc positive electrode rods 1001 and arc negative electrode rods 1002 are arranged in the axial direction of the secondary air pipe 11.

[0057] Preferably, the secondary air pipe 11 is connected to the side air inlet of the hot air hood 8 above the roasting section 4 through multiple secondary air branch pipes 12. The lower pipe section of the secondary air branch pipe 12 is bent upward to form a bent air outlet pipe section, that is, the air outlet end of the bent air outlet pipe section is communicated with the side air inlet of the hot air hood 8.

[0058] Preferably, a weighing ash hopper 13 is communicatively arranged at the lowest end of the bent air outlet pipe section. A bearing ear plate 14 extends horizontally outward from the upper hopper wall of the weighing ash hopper 13, and the bearing ear plate 14 is connected to the pipe wall below the lowest end of the bent air outlet pipe section through a weighing spring 15.

[0059] Preferably, multiple telescopic partition plates 16 are further arranged inside the bent air outlet pipe section. Along the axial direction of the bent air outlet pipe section, multiple telescopic partition plates 16 are respectively arranged in a vertical shape on the inner wall of the pipe cavity of the bent air outlet pipe section in a relatively staggered manner through multiple telescopic drive motors 17.

[0060] Preferably, a steam injection mechanism is further provided at the bottom of the first cooling section 6. The steam injection mechanism includes a main steam pipe 601 and steam branch pipes 602. The main steam pipes 601 are arranged on both sides of the air box at the bottom of the first cooling section 6, and each main steam pipe 601 is connected to the inside of the air box at the bottom of the first cooling section 6 through a plurality of steam branch pipes 602.

[0061] Preferably, a plurality of temperature measuring elements 402 are further provided in the hot air hood 8 above the roasting section 4.

[0062] Example 1

[0063] As Figures 1-9 shown, a coal-based belt roasting system includes, according to the material flow direction, a drum drying section 1, a suction drying section 2, a preheating section 3, a roasting section 4, a coal spraying and flame retardant section 5, a first cooling section 6, a second cooling section 7, and a hot air hood 8 covering each section. The top air outlet of the first cooling section 6 is connected to the air inlet of the hot air hood 8 above the roasting section 4 through a secondary air pipe 11. A feeding mechanism 9 is provided on the coal spraying and flame retardant section 5. An ignition mechanism 10 is provided in the secondary air pipe 11.

[0064] Example 2

[0065] Repeat Example 1, except that the bottom air inlets of the first cooling section 6 and the second cooling section 7 are both connected with cold air pipes. A first hot air circulation pipeline 1101 is also led out from the secondary air pipe 11 and connected to the top air inlet of the preheating section 3; the top air outlet of the second cooling section 7 is connected to the bottom air inlet of the drum drying section 1 through a second hot air circulation pipeline 701. The bottom air outlet of the roasting section 4 is connected to the top air inlet of the suction drying section 2 through a third hot air circulation pipeline 401. The top air outlets of the drum drying section 1, the bottom air outlets of the suction drying section 2, and the bottom air outlets of the preheating section 3 are all connected with exhaust air pipes.

[0066] Example 3

[0067] Repeat Example 2, except that the feeding mechanism 9 includes a mobile pulverized coal conveyor 901 and a flame retardant side spray pipe 902. An opening is provided at the top of the hot air hood 8 above the coal spraying and flame retardant section 5, and the mobile pulverized coal conveyor 901 is movably arranged above the opening. The flame retardant side spray pipe 902 is arranged on the side wall of the hot air hood 8 above the coal spraying and flame retardant section 5.

[0068] Example 4

[0069] Repeat Example 2, except that the feeding mechanism 9 includes a pulverized coal top spray pipe 903 and a flame retardant top spray pipe 904. The pulverized coal top spray pipe 903 and the flame retardant top spray pipe 904 are both arranged in the hot air hood 8 and above the material layer of the coal spraying and flame retardant section 5, and the pulverized coal top spray pipe 903 is directly above the flame retardant top spray pipe 904.

[0070] Example 5

[0071] Repeat Example 2, except that the spraying mechanism 9 includes a pulverized coal inner cylinder spray pipe 905 and a flame retardant outer cylinder spray pipe 906. The flame retardant outer cylinder spray pipe 906 is arranged at the top of the hot air hood 8 above the pulverized coal flame retardant section 5. The pulverized coal inner cylinder spray pipe 905 is sleeved inside the flame retardant outer cylinder spray pipe 906. The bottom ends of both the pulverized coal inner cylinder spray pipe 905 and the flame retardant outer cylinder spray pipe 906 penetrate through the top of the hot air hood 8 and extend into the hot air hood 8, and the bottom end of the flame retardant outer cylinder spray pipe 906 is lower than the bottom end of the pulverized coal inner cylinder spray pipe 905.

[0072] Example 6

[0073] Repeat Example 5, except that a swirl stirrer 907 is further arranged inside the flame retardant outer cylinder spray pipe 906 below the bottom end of the pulverized coal inner cylinder spray pipe 905.

[0074] Example 7

[0075] Repeat Example 6, except that the ignition mechanism 10 is an arc heating electrode, including an arc positive electrode rod 1001 and an arc negative electrode rod 1002, and the arc positive electrode rod 1001 and the arc negative electrode rod 1002 are oppositely arranged on the pipe wall of the secondary air duct 11.

[0076] Example 8

[0077] Repeat Example 7, except that multiple pairs of arc positive electrode rods 1001 and arc negative electrode rods 1002 are arranged along the circumferential direction of the pipe wall of the secondary air duct 11 and multiple pairs of arc positive electrode rods 1001 and arc negative electrode rods 1002 are arranged in the axial direction of the secondary air duct 11.

[0078] Example 9

[0079] Repeat Example 8, except that the secondary air duct 11 is connected to the side air inlet of the hot air hood 8 above the roasting section 4 through multiple secondary air branch pipes 12. The lower pipe section of the secondary air branch pipe 12 is an upwardly inclined and bent pipe section, that is, the air outlet end of the bent pipe section is communicated with the side air inlet of the hot air hood 8.

[0080] Example 10

[0081] Repeat Example 9, except that a weighing ash hopper 13 is communicatively arranged at the lowest end of the bent air outlet pipe section. A bearing ear plate 14 horizontally extends outward from the upper hopper wall of the weighing ash hopper 13, and the bearing ear plate 14 is connected to the pipe wall below the lowest end of the bent air outlet pipe section through a weighing spring 15.

[0082] Example 11

[0083] Repeat Example 10, except that a plurality of telescopic baffles 16 are further provided in the bent outlet air duct section. Along the axial direction of the bent outlet air duct section, the plurality of telescopic baffles 16 are respectively arranged in a vertical shape on the inner wall of the duct cavity of the bent outlet air duct section in a relatively staggered manner through a plurality of telescopic drive motors 17.

[0084] Example 12

[0085] Repeat Example 11, except that a steam injection mechanism is further provided at the bottom of the first cooling section 6. The steam injection mechanism includes a steam main pipe 601 and steam branch pipes 602. Steam main pipes 601 are provided on both sides of the air box at the bottom of the first cooling section 6, and each steam main pipe 601 is connected to the inside of the air box at the bottom of the first cooling section 6 through a plurality of steam branch pipes 602.

[0086] Example 13

[0087] Repeat Example 12, except that a plurality of temperature measuring elements 402 are further provided in the hot air hood 8 above the roasting section 4.

Claims

1. A coal-based belt roasting system, characterized in that: According to the direction of the material, the system comprises a drying section (1), a drying section (2), a preheating section (3), a roasting section (4), a coal injection flame retardant section (5), a cooling section (6), a second cooling section (7) and a hot air hood (8) arranged above each section in series; the top air outlet of the cooling section (6) is connected to the air inlet of the hot air hood (8) above the roasting section (4) through a secondary air duct (11); a material injection mechanism (9) is arranged on the coal injection flame retardant section (5); and an ignition mechanism (10) is arranged in the secondary air duct (11); The bottom air inlets of the first cooling section (6) and the second cooling section (7) are both connected to a cold air duct; a first hot air circulation duct (1101) is also drawn out from the secondary air duct (11) and connected to the top air inlet of the preheating section (3); the top air outlet of the second cooling section (7) is connected to the bottom air inlet of the drying section (1) through a second hot air circulation duct (701); the bottom air outlet of the roasting section (4) is connected to the top air inlet of the drying section (2) through a third hot air circulation duct (401); the top air outlet of the drying section (1), the bottom air outlet of the drying section (2) and the bottom air outlet of the preheating section (3) are all connected to an external exhaust duct.

2. The system according to claim 1, characterized in that: The spraying mechanism (9) comprises a mobile coal powder conveyor (901) and a flame retardant side nozzle (902); an opening is provided at the top of the hot air hood (8) above the coal spraying flame retardant section (5), and the mobile coal powder conveyor (901) is movably arranged above the opening; the flame retardant side nozzle (902) is arranged on the side wall of the hot air hood (8) above the coal spraying flame retardant section (5).

3. The system according to claim 1, characterized in that: The material spraying mechanism (9) comprises a coal powder top spraying pipe (903) and a flame retardant top spraying pipe (904); the coal powder top spraying pipe (903) and the flame retardant top spraying pipe (904) are both arranged in the hot air hood (8) and located above the material layer of the coal spraying flame retardant section (5), wherein the coal powder top spraying pipe (903) is located directly above the flame retardant top spraying pipe (904).

4. The system according to claim 1, characterized in that: The spraying mechanism (9) comprises a coal powder inner tube nozzle (905) and a flame retardant outer tube nozzle (906); the flame retardant outer tube nozzle (906) is arranged at the top of the hot air hood (8) above the coal spraying flame retardant section (5); the coal powder inner tube nozzle (905) is sleeved in the flame retardant outer tube nozzle (906); the bottom ends of the coal powder inner tube nozzle (905) and the flame retardant outer tube nozzle (906) both penetrate the top of the hot air hood (8) and extend into the hot air hood (8), and the bottom end of the flame retardant outer tube nozzle (906) is lower than the bottom end of the coal powder inner tube nozzle (905).

5. The system according to claim 4, characterized in that: A swirl stirrer (907) is also provided in the flame retardant outer tube nozzle (906) below the bottom end of the coal powder inner tube nozzle (905).

6. The system according to any one of claims 1 to 5, characterized in that: The ignition mechanism (10) is an arc-type heating electrode, comprising an arc positive electrode rod (1001) and an arc negative electrode rod (1002), wherein the arc positive electrode rod (1001) and the arc negative electrode rod (1002) are arranged relative to each other on the wall of the secondary air duct (11).

7. The system according to claim 6, characterized in that: A plurality of pairs of arc positive electrode rods (1001) and arc negative electrode rods (1002) are arranged on the wall of the secondary air duct (11) along its circumferential direction and / or a plurality of pairs of arc positive electrode rods (1001) and arc negative electrode rods (1002) are arranged in the axial direction of the secondary air duct (11).

8. The system according to any one of claims 1 to 5 and 7, characterized in that: The secondary air duct (11) is connected to the side air inlet of the hot air hood (8) above the roasting section (4) through a plurality of secondary air branch pipes (12); the lower pipe section of the secondary air branch pipe (12) is bent upward to form a bent air outlet pipe section, that is, the air outlet end of the bent air outlet pipe section is connected to the side air inlet of the hot air hood (8).

9. The system according to claim 6, characterized in that: The secondary air duct (11) is connected to the side air inlet of the hot air hood (8) above the roasting section (4) through a plurality of secondary air branch pipes (12); the lower pipe section of the secondary air branch pipe (12) is bent upward to form a bent air outlet pipe section, that is, the air outlet end of the bent air outlet pipe section is connected to the side air inlet of the hot air hood (8).

10. The system according to claim 8, characterized in that: A weighing ash hopper (13) is connected to the lowest end of the bent air outlet pipe section; a load-bearing ear plate (14) extends horizontally outward from the upper bucket wall of the weighing ash hopper (13), and the load-bearing ear plate (14) is connected to the pipe wall on the lower side of the lowest end of the bent air outlet pipe section through a weighing spring (15).

11. The system according to claim 9, characterized in that: A weighing ash hopper (13) is connected to the lowest end of the bent air outlet pipe section; a load-bearing ear plate (14) extends horizontally outward from the upper bucket wall of the weighing ash hopper (13), and the load-bearing ear plate (14) is connected to the pipe wall on the lower side of the lowest end of the bent air outlet pipe section through a weighing spring (15).

12. The system according to claim 10 or 11, characterized in that: A plurality of telescopic baffle plates (16) are also arranged in the bent air outlet pipe section; along the axial direction of the bent air outlet pipe section, the plurality of telescopic baffle plates (16) are arranged vertically and staggered on the inner wall of the tube cavity of the bent air outlet pipe section through a plurality of telescopic drive motors (17).

13. The system according to any one of claims 1-5, 7, 9-11, characterized in that: A water vapor injection mechanism is also provided at the bottom of the cooling section (6), the water vapor injection mechanism comprising a water vapor main pipe (601) and a water vapor branch pipe (602); water vapor main pipes (601) are provided on both sides of the wind box at the bottom of the cooling section (6), and each water vapor main pipe (601) is connected to the interior of the wind box at the bottom of the cooling section (6) through a plurality of water vapor branch pipes (602); and / or A plurality of temperature measuring elements (402) are also arranged in the hot air hood (8) above the roasting section (4).

14. The system according to claim 6, characterized in that: A water vapor injection mechanism is also provided at the bottom of the cooling section (6), the water vapor injection mechanism comprising a water vapor main pipe (601) and a water vapor branch pipe (602); water vapor main pipes (601) are provided on both sides of the wind box at the bottom of the cooling section (6), and each water vapor main pipe (601) is connected to the interior of the wind box at the bottom of the cooling section (6) through a plurality of water vapor branch pipes (602); and / or A plurality of temperature measuring elements (402) are also arranged in the hot air hood (8) above the roasting section (4).

15. The system according to claim 8, characterized in that: A water vapor injection mechanism is also provided at the bottom of the cooling section (6), the water vapor injection mechanism comprising a water vapor main pipe (601) and a water vapor branch pipe (602); water vapor main pipes (601) are provided on both sides of the wind box at the bottom of the cooling section (6), and each water vapor main pipe (601) is connected to the interior of the wind box at the bottom of the cooling section (6) through a plurality of water vapor branch pipes (602); and / or A plurality of temperature measuring elements (402) are also arranged in the hot air hood (8) above the roasting section (4).

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