A flexible adjustable coal gangue suspension calcination production system and production method

Abstract

The present application belongs to the technical field of coal gangue production, and particularly relates to a flexible and adjustable coal gangue suspension calcination production system and a production method. The flexible and adjustable coal gangue suspension calcination production system comprises, in sequence, a suspension preheating system, a calcination furnace system and a cooling system. The suspension preheating system has three stages, and a second-stage cyclone preheater to a first-stage cyclone preheater feeding point or / and a third-stage cyclone preheater to a second-stage cyclone preheater feeding point is arranged on the suspension preheating system. The cooling system comprises a first cooling system and a second cooling system. The present application provides a flexible and adjustable coal gangue suspension calcination production system and a production method, in which the combustion heat release and decomposition process of coal gangue both occur in the calcination furnace system.

Description

Technical Field

[0001] This invention belongs to the field of coal gangue production technology, and particularly relates to a flexible and adjustable coal gangue suspension calcination production system and method. Background Technology

[0002] Existing technology:

[0003] In 2021, my country's coal production reached 4 billion tons. During coal mining and coal preparation plant operations, a large amount of coal gangue (accounting for approximately 15% of coal production) is generated. Coal gangue is typically discharged onto the ground as solid waste, forming gangue mountains. According to incomplete statistics, the cumulative amount of coal gangue stockpiled in my country currently exceeds 6 billion tons. Extensive exploration and practice have been conducted both domestically and internationally regarding the comprehensive utilization of coal gangue, resulting in a comprehensive treatment and utilization system encompassing power generation, road paving, building material production, chemical raw material production, agricultural applications, and underground backfilling. However, the comprehensive utilization rate of coal gangue is less than 30%.

[0004] In the field of building materials, there has been extensive research on the application of coal gangue. For example, coal gangue is used to produce manufactured sand and gravel aggregates or co-calcined with limestone as a cementing material, but the disposal volume and application effect are not ideal. Calcination activation technology, which transfers heat from fuel combustion to coal gangue, decomposing the kaolinite (generally 40-60% content) into metakaolinite, is a feasible technical direction for the large-scale resource utilization of coal gangue. Kaolinite (Al2O3·2SiO2·2H2O, abbreviated as AS2H2) can be dehydrated at appropriate temperatures to generate metakaolinite (Al2O3·2SiO2, abbreviated as AS2). Kaolinite has a layered silicate structure, with layers bonded by van der Waals bonds. -Ions are more firmly bound within it. When kaolinite is heated in air, it undergoes several structural changes. When heated to approximately 300°C, the layered structure of kaolinite is destroyed due to dehydration, forming a poorly crystallized transition phase—meta-kaolinite. Because the molecular arrangement of meta-kaolinite is irregular, it exhibits a thermodynamically metastable state and, under appropriate stimulation, possesses cementitious properties. It can react with Ca(OH)₂ (CH₂) and water to produce volcanic ash, generating hydration products similar to those in cement. Utilizing this characteristic, when used as an admixture in cement, its reaction with the CH₂ produced during cement hydration can improve certain cement properties. Since the production cost of meta-kaolinite is lower than that of cement clinker, and the CO₂ emissions during meta-kaolinite production are also lower than those during clinker production, its use as a substitute for clinker in the building concrete and cement industries is particularly attractive, given the active promotion of carbon reduction in these industries. Furthermore, metakaolinite possesses physical properties such as low density, large specific surface area, and high oil absorption. Besides its applications in building concrete and cement additives, it can also replace pigments, plastic and rubber fillers, adsorbents, and 4A molecular sieves. It can be used as a raw material or filler in industries such as ceramics, papermaking, rubber, coatings, and petrochemicals. Its wide range of uses gives it higher economic added value. Based on this background, the preparation of metakaolinite through calcination and activation of coal gangue has promising application prospects and economic added value.

[0005] Existing coal gangue calcination and activation technologies can be divided into two main categories based on the dispersion state of the coal gangue material in the hot gas flow: sludge-state activation calcination and suspension-state activation calcination. Sludge-state calcination typically uses granular or blocky coal gangue, placed in a sludge-state arrangement within the calcination kiln. Due to the large particle size and low thermal conductivity of the coal gangue, there are problems such as a small contact area between the material and the hot gas flow, resulting in low heat exchange efficiency. Furthermore, the large temperature difference between the inside and outside of the coal gangue block leads to over-burning on the outside and under-burning on the inside, severely affecting product quality and activity. Considering that kaolinite, the main active component in coal gangue, can generate highly active metakaolinite after dehydroxylation at appropriate temperatures, this reaction is endothermic. When the temperature rises to around 300℃, kaolinite begins to decompose endothermally, generating metakaolinite and water vapor. As the temperature further increases, the decomposition rate accelerates, and decomposition essentially ends above 800℃. The decomposition rate of coal gangue is mainly affected by factors such as calcination temperature and particle size. Studies have found that the larger the particle size of coal gangue, the lower the heat transfer efficiency between materials, thus slowing down the dehydroxylation reaction rate. Therefore, grinding coal gangue into powder for suspension calcination can effectively improve the rate of the dehydroxylation reaction, i.e., utilizing suspension preheating decomposition technology to complete the preheating and decomposition process of coal gangue powder in a suspended state. Existing research shows that grinding coal gangue into powder for suspension calcination can effectively avoid the phenomenon of external over-burning and internal under-burning in the calcined coal gangue product.

[0006] Coal gangue contains a certain amount of kaolinite, which can be used as a raw material for the preparation of metakaolinite. Theoretically, metakaolinite can be prepared on a large scale through calcination and activation. However, coal gangue often contains a large amount of combustible material, which causes it to release a certain amount of heat during the preheating stage. When using coal gangue as a raw material for metakaolinite preparation, if a conventional suspension preheating system is used, the coal gangue will combust and release heat during the preheating stage (because the flue gas from preheating the coal gangue raw material contains a certain amount of oxygen, and within a suitable temperature range, the combustible material in the coal gangue will react with oxygen to produce combustion). This will cause the preheater system to become clogged and unable to operate stably for a long time. Therefore, it is necessary to develop new coal gangue calcination and activation technologies and equipment to solve the problem of clogged preheater systems when using conventional suspension preheating systems to utilize coal gangue for resource recovery, so as to achieve large-scale resource recovery of coal gangue waste.

[0007] The difficulty and significance of solving the above technical problems:

[0008] Therefore, based on the above problems, providing a flexible and adjustable coal gangue suspension calcination production system and method that allows the combustion heat release and decomposition process of coal gangue to occur within the calcination furnace system has significant practical value. Summary of the Invention

[0009] The purpose of this application is to provide a flexible and adjustable coal gangue suspension calcination production system and method that enables the combustion heat release and decomposition processes of coal gangue to occur within the calcination furnace system in order to solve the technical problems existing in the prior art.

[0010] The technical solution adopted in this application embodiment to solve the technical problems existing in the prior art is as follows:

[0011] A flexible and adjustable coal gangue suspension calcination production system, comprising a suspension preheating system, a calcination furnace system, and a cooling system connected in sequence:

[0012] The suspension preheating system has three stages, and the suspension preheating system is provided with a second-stage cyclone preheater to the feeding point of the first-stage cyclone preheater, or / and a third-stage cyclone preheater to the feeding point of the second-stage cyclone preheater;

[0013] Depending on the feeding point, the suspension preheating system can be switched to two-stage or three-stage operation. By designing multiple feeding points in the suspension preheating system, the preheater can switch between different operating stages. The number of preheater stages, feeding points, and different feeding ratios can be flexibly adjusted according to actual production needs. This ensures that the combustion heat release and decomposition processes of coal gangue all occur within the calcining furnace system.

[0014] The cooling system includes a first cooling system and a second cooling system. When the second cooling system is directly connected to the suspension preheating system, after the air leaves the outlet of the uppermost cyclone cooler of the second cooling system, one of the air streams enters the outlet of the penultimate cyclone preheater of the suspension preheating system or the outlet pipe of the calcining furnace. When the second cooling system is not directly connected to the suspension preheating system, the excess air coefficient of the flue gas at the outlet of the calcining furnace system is controlled to be 1.05 to 1.20.

[0015] The excess air coefficient of the flue gas at the outlet of the calcining furnace system is controlled at 1.05 to 1.20 to avoid or significantly reduce the heat release during the combustion of coal gangue materials in the preheating process.

[0016] The embodiments of this application may also employ the following technical solutions:

[0017] In the aforementioned flexible and adjustable coal gangue suspension calcination production system, the calcination furnace system further includes a preheating furnace and a modification furnace. The feed pipe of the penultimate cyclone preheater of the suspension preheating system is connected to the feed inlets of the preheating furnace and the modification furnace, and the outlet of the calcination furnace system is connected to the air inlet of the penultimate cyclone preheater of the suspension preheating system.

[0018] In the aforementioned flexible and adjustable coal gangue suspension calcination production system, further, the feed pipe of the penultimate cyclone preheater of the suspension preheating system is connected to the first cooling system, the feed pipe of the lowest cyclone cooler of the first cooling system is connected to the second cooling system, and the feed pipe of the lowest cyclone cooler of the second cooling system is connected to the finished product zipper machine.

[0019] In the aforementioned flexible and adjustable coal gangue suspension calcination production system, the air outlet pipe of the second cooling system is further divided into two paths: one path connects to the air inlet of the lowest-level cyclone cooler of the first cooling system, and the other path connects to the air outlet of the lowest-level cyclone preheater of the suspension preheating system or the outlet pipe of the calcining furnace.

[0020] In the aforementioned flexible and adjustable coal gangue suspension calcination production system, the exhaust pipe of the second cooling system is further divided into two paths: one path connects to the air inlet of the lowest-level cyclone cooler of the first cooling system, and the other path is discharged into the atmosphere after being treated by the flue gas treatment system.

[0021] In the aforementioned flexible and adjustable coal gangue suspension calcination production system, the air outlet pipe of the second cooling system is further divided into two paths. One path connects to the air inlet of the lowest-level cyclone cooler of the first cooling system, and the other path is further divided into two paths, each equipped with a valve. One path connects to the air outlet of the lowest-level cyclone preheater of the suspension preheating system or the outlet pipe of the calcining furnace, and the other path connects to the atmosphere.

[0022] In the aforementioned flexible and adjustable coal gangue suspension calcination production system, the suspension preheating system further includes a multi-stage cyclone preheater, a high-efficiency material spreading device, and connecting pipes; the calcination furnace system further includes a high-efficiency material spreading device, a hot air inlet pipe, a first burner arranged in the cone of the preheating furnace, a second burner arranged in the cone of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe; multiple temperature measuring points are arranged in layers along the height direction of the preheating furnace and the modification furnace; the first cooling system includes one or more stages of cyclone coolers, a high-efficiency material spreading device, and connecting pipes; the second cooling system includes one or more stages of cyclone coolers, a high-efficiency material spreading device, and connecting pipes.

[0023] In the aforementioned flexible and adjustable coal gangue suspension calcination production system, further, the number of stages of the cyclone cooler in the first cooling system is one to four; the number of stages of the cyclone cooler in the second cooling system is one to four; the calcination temperature in the calcination furnace system is 650 to 1000℃; the residence time of the gas in the calcination furnace system is 2 to 10 seconds; and the outlet flue gas temperature of the calcination furnace system is 700 to 850℃.

[0024] A flexible and adjustable coal gangue suspension calcination production process, wherein the flexible and adjustable coal gangue suspension calcination production process includes the following material flow direction and gas flow direction:

[0025] Material flow: Coal gangue raw material powder is fed into the second-stage cyclone preheater of the suspension preheating system via a feeding device to the feeding point of the first-stage cyclone preheater, or / and the third-stage cyclone preheater to the feeding point of the second-stage cyclone preheater. After heat exchange and gas-solid separation, it enters the calcining furnace system. In the calcining furnace system, the coal gangue and / or fuel combustion releases a large amount of heat for the decomposition of coal gangue. The decomposed hot material leaves the calcining furnace system and then enters the first cooling system after gas-solid separation with the hot flue gas in the lowest-stage cyclone preheater of the suspension preheating system. The hot material achieves rapid cooling and gas-solid separation in the cyclone cooler of the first cooling system. The material after rapid cooling in the first cooling system enters the second cooling system through the discharge pipe of the first cooling system. The material further achieves cooling and gas-solid separation in the cyclone cooler of the second cooling system and finally leaves from the discharge pipe of the lowest-stage cyclone cooler of the second cooling system.

[0026] Gas flow direction: ambient temperature air enters the second cooling system and cools the hot material entering the second cooling system. The air that has completed heat exchange leaves from the outlet of the top cyclone cooler of the second cooling system and then splits into two paths: one path enters the inlet of the bottom cyclone cooler of the first cooling system and cools the hot material entering the first cooling system. The air that has completed heat exchange enters the calcining furnace system through the bottom of the preheating furnace. The flue gas formed by the combustion of coal gangue and / or fuel and the decomposition of coal gangue leaves the calcining furnace system and enters the suspension preheating system. The raw material powder fed into the suspension preheating system is then preheated and gas-solid separated multiple times, and finally leaves from the outlet of the top cyclone preheater of the suspension preheating system.

[0027] The other air supply has two different scenarios. In the first scenario, the other air supply is treated by the flue gas treatment system and then discharged into the atmosphere. In the second scenario, the other air supply enters the outlet of the lowest-level cyclone preheater in the suspension preheating system or the outlet pipe of the calcining furnace to cool the flue gas temperature. The fully cooled flue gas then preheats and separates the raw material powder fed into the suspension preheating system multiple times, and finally leaves from the outlet of the highest-level cyclone preheater in the suspension preheating system. It then enters the waste heat recovery system for waste heat recovery and utilization, and is then treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere.

[0028] In the aforementioned flexible and adjustable coal gangue suspension calcination production process, furthermore, when the raw material is coal gangue with low calorific value, the fuel used in the calcination furnace system is natural gas; the excess air coefficient of the flue gas at the outlet of the calcination furnace system is 1.05 to 1.20, the calorific value of the coal gangue is 200 to 500 kcal / kg; the combustion temperature range of the coal gangue is 350 to 600℃, and the intense combustion temperature range of the coal gangue is 450 to 550℃.

[0029] One or more technical solutions provided in the embodiments of this application have at least the following beneficial effects:

[0030] 1. Existing technologies do not take into account the actual production process where coal gangue raw materials contain combustibles. This results in the coal gangue raw materials burning and releasing a large amount of heat during the suspension preheating process, causing the preheater system to become crusted and blocked, thus affecting the stable operation of the system. This invention designs the preheater into a three-stage system, adding feeding points C3 to C2 on top of the original C2 to C1 feeding points. Switching between two and three stages can be achieved based on actual production conditions. By designing multiple feeding points, the preheater can switch between different operating stages. The feeding points and different feeding ratios can be flexibly adjusted according to actual production needs, making the process operation convenient and flexible. This allows the fully preheated coal gangue material to enter the calcining furnace in a short time, ensuring that the combustion heat release and decomposition processes of the coal gangue material all occur within the calcining furnace system. On the one hand, this avoids the coal gangue raw material burning and releasing heat within the preheater system, which would increase the preheater outlet flue gas temperature and thus increase system heat consumption. On the other hand, it avoids the coal gangue burning and releasing heat within the preheater system, which could lead to scaling and blockage of the preheater system, thus affecting the stable operation of the system.

[0031] 2. A key step in the preparation of metakaolinite in this invention is the cooling of the metakaolinite. This invention sequentially sets up a first cooling system and a second cooling system from top to bottom. The high-temperature metakaolinite material is initially cooled by the first cooling system before entering the second cooling system. The first and second cooling systems have different functions and clearly defined roles:

[0032] The first cooling system is used to initially cool the high-temperature metakaolinite. The amount of cooling air used in the first cooling system is optimal to meet the normal combustion of coal gangue and fuel in the preferred calcining furnace. At this time, the amount of cooling air used in the first cooling system is the lowest, which can effectively reduce the equipment specifications of the first cooling system and thus reduce the investment cost of the system.

[0033] The optimal cooling air volume for the second cooling system is sufficient to cool the high-temperature metakaolinite to 50–120°C. At this temperature, the cooling air volume of the second cooling system is at its minimum, which can effectively reduce the equipment specifications of the second cooling system and thus reduce the system's investment cost.

[0034] 3. If only the first or second cooling system is set up, there will be many disadvantages such as incomplete fuel combustion, insufficient decomposition of kaolinite, high temperature of metakaolinite finished product that cannot meet the needs of subsequent production, too many cyclone cooler stages in the first cooling system, too many cyclone cooler stages in the second cooling system, and high system heat consumption and investment costs.

[0035] The first and second cooling systems employed in this invention enable complete fuel combustion, thorough decomposition of kaolinite, and sufficient cooling of the metakaolinite product, effectively reducing system heat consumption and investment costs. Specifically, the first cooling system is used for preliminary cooling of the calcined metakaolinite. The pre-cooled metakaolinite then enters the second cooling system and is cooled by air to the temperature required for subsequent production. The hot air, after primary heat exchange, enters the calcining furnace system as a combustion medium for the combustion of coal gangue and fuel within the furnace.

[0036] This invention, through the rational design of the suspension cooling system, enables the suspension cooling system to have multiple functions such as cooling materials, cooling flue gas, and assisting fuel combustion. Under the premise of ensuring sufficient cooling of high-temperature materials, reasonable cooling of high-temperature flue gas, and full combustion of fuel, it can achieve maximum recovery and utilization of waste heat, and even complete recovery and utilization of waste heat, with the overall energy consumption of the system at a low level.

[0037] 4. This invention takes into account the actual needs of processing coal gangue containing combustible materials and the actual characteristics of coal gangue containing combustible materials, and produces highly active metakaolinite products. At the same time, it solves the problems of heat release during coal gangue preheating leading to crusting and blockage of the preheater system, and the complex production process of the metakaolinite production system, high system energy consumption, and easy overburning of products.

[0038] 5. This invention does not include a hot blast stove. The air outlet of the first cooling system is directly connected to the bottom of the preheating furnace, avoiding the following three defects of the hot blast stove: First, the heat storage capacity of the calcining furnace system is poor. It relies solely on the enthalpy carried by the sensible heat of the flue gas from the hot blast stove to heat the material through heat exchange, promoting the decomposition of kaolin material, resulting in low reaction efficiency. Second, the adjustment is lagging. There is usually a long pipeline distance between the hot blast stove and the calcining furnace system, which results in a certain amount of heat loss and lagging adjustment. Third, the process flow is relatively complex.

[0039] 6. When the second cooling system and the suspension preheating system are directly connected, after the air leaves the outlet of the uppermost cyclone cooler of the second cooling system, one of the air streams enters the outlet of the lowermost cyclone preheater of the suspension preheating system or the outlet pipe of the calcining furnace. This can cool the flue gas temperature at the outlet of the lowermost cyclone preheater of the suspension preheating system or the outlet of the calcining furnace to a reasonable temperature range (ideally lower than the temperature range of intense combustion of coal gangue), thus avoiding the release of heat from combustion of coal gangue during the preheating process.

[0040] 7. When the second cooling system and the suspension preheating system are not directly connected, the present invention can control the oxygen content in the flue gas at the outlet of the calcining furnace system to a relatively low level by reasonably designing the excess air coefficient of the flue gas at the outlet of the calcining furnace system. At this time, even if low oxygen high temperature flue gas is used to preheat the coal gangue raw material, the possibility of the coal gangue material releasing heat during the preheating process can be avoided or greatly alleviated. Attached Figure Description

[0041] The technical solutions of the embodiments of this application will be further described in detail below with reference to the accompanying drawings. However, it should be understood that these drawings are designed for illustrative purposes only and are not intended to limit the scope of this application. In addition, unless otherwise specified, these drawings are only intended to conceptually illustrate the structural construction described herein and are not necessarily drawn to scale.

[0042] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention;

[0043] Figure 2 This is a process flow diagram of Embodiment 2 of the present invention;

[0044] Figure 3 This is a process flow diagram of Embodiment 3 of the present invention;

[0045] Figure 4 This is a process flow diagram of Embodiment 4 of the present invention;

[0046] Figure 5 This is a process flow diagram of Embodiment 5 of the present invention;

[0047] Figure 6 This is a process flow diagram of Embodiment Six of the present invention;

[0048] Figure 7 This is a process flow diagram of Embodiment Seven of the present invention;

[0049] Figure 8 This is a process flow diagram of Embodiment 8 of the present invention;

[0050] Figure 9 This is a process flow diagram of Embodiment Nine of the present invention. Detailed Implementation

[0051] Considering that coal gangue raw materials often contain a lot of combustible materials, and will release a certain amount of heat during the suspension preheating stage, when coal gangue is used as a raw material for the preparation of metakaolinite, the coal gangue will burn and release heat during the suspension preheating stage, which will cause the preheater system to become clogged and unable to operate stably for a long time. In order to ensure the stable operation of the suspension calcination system and controllable product quality, it is necessary to control the combustion and heat release process of combustible materials in coal gangue to occur in the calcination furnace.

[0052] According to experimental research, the combustion temperature range of combustible materials in coal gangue is generally 350-600℃, and the intense combustion temperature range is generally 450-550℃. Therefore, it is necessary to rationally design several key factors such as the number of preheater stages, feeding points, flue gas temperature, and oxygen content in the flue gas so that all coal gangue in the above-mentioned combustion temperature range, especially the intense combustion temperature range, is located in the calcining furnace. Specifically, firstly, the flue gas temperature for preheating coal gangue needs to be reasonably controlled (ideally below the temperature range of intense coal gangue combustion); secondly, by rationally designing the number of preheater stages and the raw material feeding points, the preheated coal gangue material can enter the calcining furnace in a shorter time, reducing system heat consumption while avoiding heat release during combustion within the preheater; finally, by rationally designing the air volume of the first cooling system, the excess air coefficient of the flue gas at the outlet of the calcining furnace system can be controlled at a relatively low level (i.e., the oxygen content in the flue gas at the outlet of the calcining furnace system is controlled at a relatively low level). At this point, even if low-oxygen, high-temperature flue gas is used to preheat the coal gangue raw material, the possibility of heat release during combustion of the coal gangue material during preheating can be avoided or significantly mitigated.

[0053] In the process, kaolinite-containing coal gangue raw material first enters the drying and crushing mill, where it is dried and crushed to obtain raw material powder that meets production requirements. The raw material powder is then fed into the suspension preheating system via a feeding device from feeding point C2 to C1 (referred to as feeding point A), or from feeding point C3 to C2 (referred to as feeding point B), or simultaneously from feeding point C2 to C1 (referred to as feeding point A) and feeding point C3 to C2 (referred to as feeding point B). The suspension preheating system includes a multi-stage cyclone preheater, a high-efficiency material spreading device, and connecting pipes. The raw material powder undergoes preheating and gas-solid separation in the cyclone preheater. After heat exchange and gas-solid separation, the raw material powder enters the calcining furnace system through the discharge pipe of the penultimate stage cyclone preheater of the suspension preheating system. The calcining furnace system includes a high-efficiency feeding device, a hot air inlet pipe, a preheating furnace, a first burner arranged in the cone of the preheating furnace, a modification furnace, a second burner arranged in the cone of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe, etc. Multiple temperature measuring points are set up in layers along the height of the preheating furnace and the modification furnace to monitor the temperature distribution inside the preheating furnace and the modification furnace in real time. By adjusting the amount of fuel and material fed into the preheating furnace and the modification furnace, the temperature distribution inside the preheating furnace and the modification furnace is controlled within a reasonable range. The reasonable temperature distribution inside the preheating furnace and the modification furnace can ensure the complete combustion of coal gangue (and fuel) and the complete decomposition of coal gangue (when the calorific value of coal gangue is within the applicable range, the heat contained in it can meet the heat requirements of the decomposition process of kaolinite in coal gangue, without the need to add extra fuel or only a small amount of fuel is needed. This is the complete combustion of coal gangue. In other cases, it is the complete combustion of fuel and coal gangue). At the same time, it ensures that the coal gangue is not overburned, and the activity of the finished product relative to kaolinite meets the requirements of subsequent production. In the calcining furnace system, the combustion of coal gangue (and fuel) releases a large amount of heat for the decomposition of the coal gangue. The decomposed hot material leaves the calcining furnace system and then undergoes gas-solid separation with the hot flue gas in the lowest-level cyclone preheater of the suspension preheating system before entering the first cooling system. The first cooling system includes one or more cyclone coolers, a high-efficiency material spreading device, and connecting pipes. The hot material undergoes rapid cooling and gas-solid separation in the cyclone coolers of the first cooling system. After rapid cooling, the material, after gas-solid separation, enters the second cooling system through the discharge pipe of the lowest-level cyclone cooler in the first cooling system. The second cooling system includes one or more cyclone coolers, a high-efficiency material spreading device, and connecting pipes. The material undergoes further cooling and gas-solid separation in the cyclone coolers of the second cooling system, and finally exits through the discharge pipe of the lowest-level cyclone cooler in the second cooling system, falling into the finished product zipper machine to obtain the desired finished product.

[0054] Ambient air enters the second cooling system, subsequently cooling the hot material entering the system. The air, having completed heat exchange, exits from the outlet of the top-level cyclone cooler in the second cooling system. After being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). It then splits into two paths: one path enters the inlet of the bottom-level cyclone cooler in the first cooling system, cooling the hot material entering the first cooling system. The air, having completed heat exchange, enters the calcining furnace system through the bottom of the preheating furnace. The flue gas formed from the combustion and decomposition of coal gangue (and fuel) in the calcining furnace system exits the calcining furnace system and enters the suspension preheating system. The raw material powder fed into the suspension preheating system undergoes multiple preheating and gas-solid separation processes, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system.

[0055] Furthermore, the flue gas leaving the outlet of the top-level cyclone preheater of the suspension preheating system then enters the waste heat utilization system (such as a waste heat boiler) for waste heat recovery and utilization. The flue gas after waste heat utilization can enter the raw material grinding system to dry coal gangue raw materials, and after being treated by the dust collection system and the flue gas treatment system, it can be discharged into the atmosphere, or it can be directly discharged into the atmosphere after being treated by the dust collection system and the flue gas treatment system.

[0056] The other air supply has two different design schemes. In the first scheme, the other air is treated by the flue gas treatment system before being discharged into the atmosphere. In the second scheme (which also applies when the raw material is coal gangue with low calorific value), the other air enters the outlet of the lowest-level cyclone preheater in the suspension preheating system or the outlet pipe of the calcining furnace to cool the flue gas temperature. Then, it performs multiple preheating and gas-solid separation processes on the raw material powder fed into the suspension preheating system, and finally leaves from the outlet of the highest-level cyclone preheater in the suspension preheating system. After that, it enters the waste heat recovery system for waste heat recovery and utilization, and is then treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere.

[0057] Furthermore, the preferred number of stages for the cyclone preheater in the suspension preheating system is three; the preferred number of stages for the cyclone cooler in the first cooling system is one to four; the preferred number of stages for the cyclone cooler in the second cooling system is one to four; the preferred calcination temperature in the calcination furnace system is 650 to 1000°C; the preferred residence time of the gas in the calcination furnace system is 2 to 10 seconds; and the preferred outlet flue gas temperature of the calcination furnace system is 700 to 850°C.

[0058] When the raw material is coal gangue with low calorific value, the fuel used in the calcining furnace system is preferably natural gas; the excess air coefficient of the flue gas at the outlet of the calcining furnace system is preferably 1.05 to 1.20; and the calorific value of the coal gangue is preferably 200 to 500 kcal / kg.

[0059] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0060] Example 1

[0061] In this embodiment, the suspension preheating system includes first, second, and third cyclone preheaters, a high-efficiency material spreading device, and connecting pipes; the calcining furnace system includes a high-efficiency material spreading device, a hot air inlet pipe, a preheating furnace, a first burner arranged in the cone of the preheating furnace, a modification furnace, a second burner arranged in the cone of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe; the first cooling system includes fourth and fifth cyclone coolers, a high-efficiency material spreading device, and connecting pipes; the second cooling system includes a sixth and seventh cyclone cooler, a high-efficiency material spreading device, and connecting pipes.

[0062] like Figure 1 As shown, kaolinite-containing coal gangue raw material first enters the drying and crushing mill, where it is dried and crushed to obtain raw material powder that meets production requirements. The raw material powder is then fed into the suspension preheating system via a feeding device from feeding points C2 to C1 (denoted as feeding point A). Preheating and gas-solid separation are achieved in the cyclone preheater. After heat exchange and gas-solid separation, the raw material powder enters the calcining furnace system through the discharge pipe of the second cyclone preheater. By adjusting the material ratio fed into the preheating furnace and modification furnace of the calcining furnace system, the temperature distribution in the preheating furnace and modification furnace can be controlled within a reasonable range. A reasonable temperature distribution in the preheating furnace and modification furnace ensures complete combustion of coal gangue and complete decomposition of kaolinite, while preventing kaolinite from overburning, and ensuring that the activity of the finished product meets the requirements of subsequent production. The combustion of coal gangue in the calcining furnace system releases a large amount of heat to decompose kaolinite. The decomposed hot material leaves the calcining furnace system and then enters the first cooling system after gas-solid separation with the hot flue gas in the third cyclone preheater. The hot material is cooled and separated into gas and solid in the cyclone cooler of the first cooling system. After being cooled by the first cooling system, the hot material is separated into gas and solid and then enters the second cooling system through the feed pipe of the fifth cyclone cooler. The material is further cooled and separated into gas and solid in the cyclone cooler of the second cooling system, and finally leaves through the feed pipe of the sixth cyclone cooler and falls into the finished product zipper machine to obtain the finished product that meets the requirements.

[0063] In terms of gas flow direction, ambient temperature air enters the second cooling system, subsequently cooling the hot material entering the second cooling system. The air that has completed heat exchange leaves from the outlet of the top-level cyclone cooler in the second cooling system, and after being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). Then it splits into two paths: one path of air enters the inlet of the bottom-level cyclone cooler in the first cooling system, subsequently cooling the hot material entering the first cooling system. The air that has completed heat exchange enters the calcining furnace system through the bottom of the preheating furnace. The flue gas formed by the combustion of coal gangue and the decomposition of kaolinite in the calcining furnace system leaves the calcining furnace system and enters the suspension preheating system. It then preheats and separates the raw material powder fed into the suspension preheating system multiple times, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system. The flue gas then enters the waste heat recovery system for waste heat recovery and utilization, and is discharged into the atmosphere after treatment by the dust collection system and the flue gas treatment system. Another path of air enters the outlet of the bottom-level cyclone preheater in the suspension preheating system or the calcining furnace outlet pipe to cool the flue gas temperature. The fully cooled flue gas then preheats and separates the raw material powder fed into the suspension preheating system multiple times, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system. The flue gas then enters the waste heat recovery system for waste heat recovery and utilization, and is discharged into the atmosphere after treatment by the dust collection system and the flue gas treatment system.

[0064] Example 2

[0065] In this embodiment, the suspension preheating system includes first, second, and third cyclone preheaters, a high-efficiency material spreading device, and connecting pipes; the calcining furnace system includes a high-efficiency material spreading device, a hot air inlet pipe, a preheating furnace, a first burner arranged in the cone of the preheating furnace, a modification furnace, a second burner arranged in the cone of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe; the first cooling system includes fourth and fifth cyclone coolers, a high-efficiency material spreading device, and connecting pipes; the second cooling system includes a sixth and seventh cyclone cooler, a high-efficiency material spreading device, and connecting pipes.

[0066] like Figure 2As shown, kaolinite-containing coal gangue raw material first enters the drying and crushing mill. Inside the mill, it undergoes drying and crushing to obtain raw material powder that meets production requirements. This powder is then fed into the suspension preheating system (at this point, the first cyclone preheater functions similarly to the duct) via a feeding device from feeding points C3 to C2. Preheating and gas-solid separation are achieved within the cyclone preheater. After heat exchange and gas-solid separation, the powder enters the calcining furnace system through the discharge pipe of the second cyclone preheater. By adjusting the material ratio fed into the preheating furnace and modification furnace of the calcining furnace system, the temperature distribution within both furnaces is controlled within a reasonable range. This reasonable temperature distribution ensures complete combustion of the coal gangue and complete decomposition of the kaolinite, while preventing over-burning of the kaolinite, ensuring the finished product's activity meets subsequent production requirements. The combustion of fuel in the calcining furnace system releases a large amount of heat to decompose kaolinite. The decomposed hot material leaves the calcining furnace system and then enters the first cooling system after gas-solid separation with the hot flue gas in the third cyclone preheater. The hot material is cooled and separated into gas and solid in the cyclone cooler of the first cooling system. After being cooled by the first cooling system, the material is separated into gas and solid and then enters the second cooling system through the feed pipe of the fifth cyclone cooler. The material is further cooled and separated into gas and solid in the cyclone cooler of the second cooling system, and finally leaves through the feed pipe of the sixth cyclone cooler and falls into the finished product zipper machine to obtain the finished product that meets the requirements.

[0067] In terms of gas flow direction, ambient temperature air enters the second cooling system, subsequently cooling the hot material entering the second cooling system. The air that has completed heat exchange leaves from the outlet of the top-level cyclone cooler in the second cooling system, and after being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). Then it splits into two paths: one path of air enters the inlet of the bottom-level cyclone cooler in the first cooling system, subsequently cooling the hot material entering the first cooling system. The air that has completed heat exchange enters the calcining furnace system through the bottom of the preheating furnace. The flue gas formed by the combustion of coal gangue and the decomposition of kaolinite in the calcining furnace system leaves the calcining furnace system and enters the suspension preheating system. It then preheats and separates the raw material powder fed into the suspension preheating system multiple times, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system. It then enters the waste heat recovery system for waste heat recovery and utilization, and is subsequently treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere. Another path of air enters the outlet of the bottom-level cyclone preheater in the suspension preheating system or the calcining furnace outlet pipe to cool the flue gas temperature. The fully cooled flue gas then preheats and separates the raw material powder fed into the suspension preheating system multiple times, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system. It then enters the waste heat recovery system for waste heat recovery and utilization, and is subsequently treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere.

[0068] Example 3

[0069] In this embodiment, the suspension preheating system includes first, second, and third cyclone preheaters, a high-efficiency material spreading device, and connecting pipes; the calcining furnace system includes a high-efficiency material spreading device, a hot air inlet pipe, a preheating furnace, a first burner arranged in the cone of the preheating furnace, a modification furnace, a second burner arranged in the cone of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe; the first cooling system includes fourth and fifth cyclone coolers, a high-efficiency material spreading device, and connecting pipes; the second cooling system includes a sixth and seventh cyclone cooler, a high-efficiency material spreading device, and connecting pipes.

[0070] like Figure 3 As shown, kaolinite-containing coal gangue raw material first enters the drying and crushing mill, where it is dried and crushed to obtain raw material powder that meets production requirements. Simultaneously, the raw material powder is fed into the suspension preheating system via feeding devices from feeding points C2 to C1 (denoted as feeding point A) and C3 to C2 (denoted as feeding point B). (The feeding ratio between feeding points A and B can be flexibly adjusted according to actual site conditions). Preheating and gas-solid separation are achieved in the cyclone preheater. After heat exchange and gas-solid separation, the raw material powder enters the calcining furnace system through the discharge pipe of the second cyclone preheater. By adjusting the material ratio fed into the preheating furnace and modification furnace of the calcining furnace system, the temperature distribution within the preheating furnace and modification furnace is controlled within a reasonable range. A reasonable temperature distribution within the preheating furnace and modification furnace ensures complete combustion of coal gangue and complete decomposition of kaolinite, while preventing over-burning of kaolinite, ensuring the finished product's activity meets subsequent production requirements. The combustion of fuel in the calcining furnace system releases a large amount of heat to decompose kaolinite. The decomposed hot material leaves the calcining furnace system and then enters the first cooling system after gas-solid separation with the hot flue gas in the third cyclone preheater. The hot material is cooled and separated into gas and solid in the cyclone cooler of the first cooling system. After being cooled by the first cooling system, the material is separated into gas and solid and then enters the second cooling system through the feed pipe of the fifth cyclone cooler. The material is further cooled and separated into gas and solid in the cyclone cooler of the second cooling system, and finally leaves through the feed pipe of the sixth cyclone cooler and falls into the finished product zipper machine to obtain the finished product that meets the requirements.

[0071] In terms of gas flow direction, ambient temperature air enters the second cooling system, subsequently cooling the material entering the second cooling system. The air that has completed heat exchange leaves from the outlet of the top-level cyclone cooler in the second cooling system, and after being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). Then it splits into two paths: one path of air enters the inlet of the bottom-level cyclone cooler in the first cooling system, subsequently cooling the hot material entering the first cooling system. The air that has completed heat exchange enters the calcining furnace system through the bottom of the preheating furnace. The flue gas formed by the combustion of coal gangue and the decomposition of kaolinite in the calcining furnace system leaves the calcining furnace system and enters the suspension preheating system. It then preheats and separates the raw material powder fed into the suspension preheating system multiple times, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system. It then enters the waste heat recovery system for waste heat recovery and utilization, and is subsequently treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere. Another path enters the outlet of the bottom-level cyclone preheater in the suspension preheating system or the calcining furnace outlet pipe to cool the flue gas temperature. The fully cooled flue gas then preheats and separates the raw material powder fed into the suspension preheating system multiple times, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system. It then enters the waste heat recovery system for waste heat recovery and utilization, and is subsequently treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere.

[0072] Example 4

[0073] In this embodiment, the suspension preheating system includes first, second, and third cyclone preheaters, a high-efficiency material spreading device, and connecting pipes; the calcining furnace system includes a high-efficiency material spreading device, a hot air inlet pipe, a preheating furnace, a first burner arranged in the cone of the preheating furnace, a modification furnace, a second burner arranged in the cone of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe; the first cooling system includes fourth and fifth cyclone coolers, a high-efficiency material spreading device, and connecting pipes; the second cooling system includes a sixth and seventh cyclone cooler, a high-efficiency material spreading device, and connecting pipes.

[0074] like Figure 4As shown, low-calorific-value coal gangue containing kaolinite first enters the drying and crushing mill. Inside the mill, it is dried and crushed to obtain raw material powder that meets production requirements. This powder is then fed into the suspension preheating system via a feeding device from feeding points C2 to C1 (denoted as feeding point A). Preheating and gas-solid separation are achieved in the cyclone preheater. After heat exchange and gas-solid separation, the powder enters the calcining furnace system through the discharge pipe of the second cyclone preheater. By adjusting the fuel and material ratios in the preheating and modification furnaces of the calcining furnace system, the temperature distribution within these furnaces is controlled within a reasonable range. This reasonable temperature distribution ensures complete combustion of the coal gangue and fuel, and complete decomposition of the kaolinite, while preventing over-burning of the kaolinite, ensuring the finished product's activity meets subsequent production requirements. In the calcining furnace system, the combustion of coal gangue and fuel releases a large amount of heat for the decomposition of kaolinite. The decomposed hot material leaves the calcining furnace system and then enters the first cooling system after gas-solid separation with the hot flue gas in the third cyclone preheater. The hot material is cooled and separated into gas and solid in the cyclone cooler of the first cooling system. After being cooled by the first cooling system, the material is separated into gas and solid and then enters the second cooling system through the feed pipe of the fifth cyclone cooler. The material is further cooled and separated into gas and solid in the cyclone cooler of the second cooling system, and finally leaves through the feed pipe of the sixth cyclone cooler and falls into the finished product zipper machine to obtain the finished product that meets the requirements.

[0075] In terms of gas flow direction, ambient temperature air enters the second cooling system, subsequently cooling the hot material entering the second cooling system. The air that has completed heat exchange leaves from the outlet of the top-level cyclone cooler in the second cooling system, and after being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). Then it splits into two paths: one path of air enters the inlet of the bottom-level cyclone cooler in the first cooling system, subsequently cooling the hot material entering the first cooling system. The air that has completed heat exchange enters the calcining furnace system through the bottom of the preheating furnace. The flue gas generated from the combustion of coal gangue and fuel, as well as the decomposition of coal gangue, leaves the calcining furnace system and enters the suspension preheating system. The raw material powder fed into the suspension preheating system undergoes multiple preheating and gas-solid separation processes. Finally, the flue gas exits from the outlet of the top-level cyclone preheater in the suspension preheating system and then enters the waste heat boiler for waste heat utilization. After waste heat utilization, the flue gas enters the raw material grinding system to dry the coal gangue raw material. It is then treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere. Another path of air is treated by the flue gas treatment system before being discharged into the atmosphere.

[0076] Example 5

[0077] In this embodiment, the suspension preheating system includes first, second, and third cyclone preheaters, a high-efficiency material spreading device, and connecting pipes; the calcining furnace system includes a high-efficiency material spreading device, a hot air inlet pipe, a preheating furnace, a first burner arranged in the cone of the preheating furnace, a modification furnace, a second burner arranged in the cone of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe; the first cooling system includes fourth and fifth cyclone coolers, a high-efficiency material spreading device, and connecting pipes; the second cooling system includes a sixth and seventh cyclone cooler, a high-efficiency material spreading device, and connecting pipes.

[0078] like Figure 5 As shown, low-calorific-value coal gangue containing kaolinite first enters the drying and crushing mill. Inside the mill, it is dried and crushed to obtain raw material powder that meets production requirements. This powder is then fed into the suspension preheating system (at this point, the first cyclone preheater functions similarly to the duct) via a feeding device from feeding points C3 to C2. Preheating and gas-solid separation are achieved in the cyclone preheater. After heat exchange and gas-solid separation, the powder enters the calcining furnace system through the discharge pipe of the second cyclone preheater. By adjusting the fuel and material ratios in the preheating and modification furnaces of the calcining furnace system, the temperature distribution within these furnaces is controlled within a reasonable range. This reasonable temperature distribution ensures complete combustion of the coal gangue and fuel, and complete decomposition of the kaolinite, while preventing over-burning of the kaolinite, ensuring the finished product's activity meets subsequent production requirements. In the calcining furnace system, the combustion of coal gangue and fuel releases a large amount of heat for the decomposition of kaolinite. The decomposed hot material leaves the calcining furnace system and then enters the first cooling system after gas-solid separation with the hot flue gas in the third cyclone preheater. The hot material is cooled and separated into gas and solid in the cyclone cooler of the first cooling system. After being cooled by the first cooling system, the material is separated into gas and solid and then enters the second cooling system through the feed pipe of the fifth cyclone cooler. The material is further cooled and separated into gas and solid in the cyclone cooler of the second cooling system, and finally leaves through the feed pipe of the sixth cyclone cooler and falls into the finished product zipper machine to obtain the finished product that meets the requirements.

[0079] In terms of gas flow direction, ambient temperature air enters the second cooling system, subsequently cooling the hot material entering the second cooling system. The air that has completed heat exchange leaves from the outlet of the top-level cyclone cooler in the second cooling system, and after being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). Then it splits into two paths: one path of air enters the inlet of the bottom-level cyclone cooler in the first cooling system, subsequently cooling the hot material entering the first cooling system. The air that has completed heat exchange enters the calcining furnace system through the bottom of the preheating furnace. The flue gas generated from the combustion of coal gangue and fuel, as well as the decomposition of coal gangue, leaves the calcining furnace system and enters the suspension preheating system. The raw material powder fed into the suspension preheating system undergoes multiple preheating and gas-solid separation processes. Finally, the flue gas exits from the outlet of the top-level cyclone preheater in the suspension preheating system and then enters the waste heat boiler for waste heat utilization. After waste heat utilization, the flue gas enters the raw material grinding system to dry the coal gangue raw material. It is then treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere. Another path of air is treated by the flue gas treatment system before being discharged into the atmosphere.

[0080] Example 6

[0081] In this embodiment, the suspension preheating system includes first, second, and third cyclone preheaters, a high-efficiency material spreading device, and connecting pipes; the calcining furnace system includes a high-efficiency material spreading device, a hot air inlet pipe, a preheating furnace, a first burner arranged in the cone of the preheating furnace, a modification furnace, a second burner arranged in the cone of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe; the first cooling system includes fourth and fifth cyclone coolers, a high-efficiency material spreading device, and connecting pipes; the second cooling system includes a sixth and seventh cyclone cooler, a high-efficiency material spreading device, and connecting pipes.

[0082] like Figure 6As shown, low-calorific-value coal gangue containing kaolinite first enters the drying and crushing mill. Inside the mill, it is dried and crushed to obtain raw material powder that meets production requirements. Simultaneously, the raw material powder is fed into the suspension preheating system via feeding devices from feeding points C2 to C1 (denoted as feeding point A) and C3 to C2 (denoted as feeding point B). (The feeding ratio between feeding points A and B can be flexibly adjusted according to actual site conditions). Preheating and gas-solid separation are achieved in the cyclone preheater. After heat exchange and gas-solid separation, the raw material powder enters the calcining furnace system through the discharge pipe of the second cyclone preheater. By adjusting the fuel and material ratios fed into the preheating and modification furnaces of the calcining furnace system, the temperature distribution within the preheating and modification furnaces is controlled within a reasonable range. This reasonable temperature distribution ensures complete combustion of coal gangue and fuel, and complete decomposition of kaolinite, while preventing over-burning of kaolinite, ensuring the finished product's activity meets subsequent production requirements. In the calcining furnace system, the combustion of coal gangue and fuel releases a large amount of heat for the decomposition of kaolinite. The decomposed hot material leaves the calcining furnace system and then enters the first cooling system after gas-solid separation with the hot flue gas in the third cyclone preheater. The hot material is cooled and separated into gas and solid in the cyclone cooler of the first cooling system. After being cooled by the first cooling system, the material is separated into gas and solid and then enters the second cooling system through the feed pipe of the fifth cyclone cooler. The material is further cooled and separated into gas and solid in the cyclone cooler of the second cooling system, and finally leaves through the feed pipe of the sixth cyclone cooler and falls into the finished product zipper machine to obtain the finished product that meets the requirements.

[0083] In terms of gas flow direction, ambient temperature air enters the second cooling system, subsequently cooling the hot material entering the second cooling system. The air that has completed heat exchange leaves from the outlet of the top-level cyclone cooler in the second cooling system, and after being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). Then it splits into two paths: one path of air enters the inlet of the bottom-level cyclone cooler in the first cooling system, subsequently cooling the hot material entering the first cooling system. The air that has completed heat exchange enters the calcining furnace system through the bottom of the preheating furnace. The flue gas generated from the combustion of coal gangue and fuel and the decomposition of coal gangue in the calcining furnace system leaves the calcining furnace system and enters the suspension preheating system. The raw material powder fed into the suspension preheating system is then preheated and separated into gas and solid multiple times. Finally, it leaves from the outlet of the cyclone preheater at the top of the suspension preheating system and then enters the waste heat boiler for waste heat utilization. The flue gas after waste heat utilization enters the raw material grinding system to dry the coal gangue raw material. After being treated by the dust collection system and the flue gas treatment system, it is discharged into the atmosphere. Another air path is treated by the flue gas treatment system before being discharged into the atmosphere.

[0084] Example 7

[0085] In terms of material flow, kaolinite-containing coal gangue raw material first enters the drying and crushing mill, where it undergoes drying and crushing to obtain raw material powder that meets production requirements. The raw material powder is then fed into the suspension preheating system via a feeding device from feeding points C2 to C1 (denoted as feeding point A). The suspension preheating system includes a multi-stage cyclone preheater, a high-efficiency spreading device, and connecting pipes. The raw material powder undergoes preheating and gas-solid separation within the cyclone preheater. After heat exchange and gas-solid separation, the raw material powder enters the calcining furnace system through the discharge pipe of the penultimate stage cyclone preheater in the suspension preheating system. The calcining furnace system includes a high-efficiency spreading device, a hot air inlet pipe, a preheating furnace, a first burner located in the cone section of the preheating furnace, a modification furnace, a second burner located in the cone section of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe. Multiple temperature measuring points are set up in layers along the height of the preheating furnace and the modification furnace to monitor the temperature distribution inside the preheating furnace and the modification furnace in real time. By adjusting the amount of fuel and material fed into the preheating furnace and the modification furnace, the temperature distribution inside the preheating furnace and the modification furnace is controlled within a reasonable range. The reasonable temperature distribution inside the preheating furnace and the modification furnace can ensure the complete combustion of coal gangue (and fuel) and the complete decomposition of coal gangue (when the calorific value of coal gangue is within the applicable range, the heat contained in it can meet the heat requirements for the decomposition of kaolinite in coal gangue, without the need to add extra fuel or only a small amount of fuel is needed, which is the complete combustion of coal gangue; in other cases, it is the complete combustion of fuel and coal gangue). At the same time, it ensures that the coal gangue is not overburned, and the activity of the finished product relative to kaolinite meets the requirements of subsequent production. In the calcining furnace system, the combustion of coal gangue (and fuel) releases a large amount of heat for the decomposition of the coal gangue. The decomposed hot material leaves the calcining furnace system and then undergoes gas-solid separation with the hot flue gas in the lowest-level cyclone preheater of the suspension preheating system before entering the first cooling system. The first cooling system includes one or more cyclone coolers, a high-efficiency material spreading device, and connecting pipes. The hot material undergoes rapid cooling and gas-solid separation in the cyclone coolers of the first cooling system. After rapid cooling, the material, after gas-solid separation, enters the second cooling system through the discharge pipe of the lowest-level cyclone cooler in the first cooling system. The second cooling system includes one or more cyclone coolers, a high-efficiency material spreading device, and connecting pipes. The material undergoes further cooling and gas-solid separation in the cyclone coolers of the second cooling system, and finally exits through the discharge pipe of the lowest-level cyclone cooler in the second cooling system, falling into the finished product zipper machine to obtain the desired finished product.

[0086] In terms of gas flow direction: At-temperature air enters the second cooling system, subsequently cooling the hot material entering the system. The air, having completed heat exchange, exits from the outlet of the top-level cyclone cooler in the second cooling system. After being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). It then splits into two paths: one path enters the bottom-level cyclone cooler in the first cooling system, cooling the hot material entering the first cooling system. The air, having completed heat exchange, enters the calcining furnace system through the bottom of the preheating furnace. The flue gas formed from the combustion and decomposition of coal gangue (and fuel) in the calcining furnace system exits the calcining furnace system and enters the suspension preheating system. There, the raw material powder fed into the suspension preheating system undergoes multiple preheating and gas-solid separation processes, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system.

[0087] The other air supply has two different design schemes. In the first scheme, the other air supply is treated by the flue gas treatment system before being discharged into the atmosphere. In the second scheme (which also applies when the raw material is coal gangue with low calorific value), the other air supply enters the outlet of the lowest-level cyclone preheater in the suspension preheating system or the outlet pipe of the calcining furnace to cool the flue gas temperature. The fully cooled flue gas then preheats and separates the raw material powder fed into the suspension preheating system multiple times, and finally leaves from the outlet of the highest-level cyclone preheater in the suspension preheating system. It then enters the waste heat recovery system for waste heat recovery and utilization, and is finally discharged into the atmosphere after being treated by the dust collection system and the flue gas treatment system.

[0088] Furthermore, the flue gas exits from the outlet of the top-level cyclone preheater of the suspension preheating system, then enters the waste heat recovery system for waste heat recovery and utilization, and is then discharged into the atmosphere after being treated by the dust collection system and the flue gas treatment system.

[0089] Example 8

[0090] In terms of material flow, kaolinite-containing coal gangue raw material first enters the drying and crushing mill, where it undergoes drying and crushing to obtain raw material powder that meets production requirements. The raw material powder is then fed into the suspension preheating system via a feeding device from feeding points C3 to C2 (denoted as feeding point B). The suspension preheating system includes a multi-stage cyclone preheater, a high-efficiency spreading device, and connecting pipes. The raw material powder undergoes preheating and gas-solid separation within the cyclone preheater. After heat exchange and gas-solid separation, the raw material powder enters the calcining furnace system through the discharge pipe of the penultimate stage cyclone preheater in the suspension preheating system. The calcining furnace system includes a high-efficiency spreading device, a hot air inlet pipe, a preheating furnace, a first burner located in the cone section of the preheating furnace, a modification furnace, a second burner located in the cone section of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe. Multiple temperature measuring points are set up in layers along the height of the preheating furnace and the modification furnace to monitor the temperature distribution inside the preheating furnace and the modification furnace in real time. By adjusting the amount of fuel and material fed into the preheating furnace and the modification furnace, the temperature distribution inside the preheating furnace and the modification furnace is controlled within a reasonable range. The reasonable temperature distribution inside the preheating furnace and the modification furnace can ensure the complete combustion of coal gangue (and fuel) and the complete decomposition of coal gangue (when the calorific value of coal gangue is within the applicable range, the heat contained in it can meet the heat requirements for the decomposition of kaolinite in coal gangue, without the need to add extra fuel or only a small amount of fuel is needed, which is the complete combustion of coal gangue; in other cases, it is the complete combustion of fuel and coal gangue). At the same time, it ensures that the coal gangue is not overburned, and the activity of the finished product relative to kaolinite meets the requirements of subsequent production. In the calcining furnace system, the combustion of coal gangue (and fuel) releases a large amount of heat for the decomposition of the coal gangue. The decomposed hot material leaves the calcining furnace system and then undergoes gas-solid separation with the hot flue gas in the lowest-level cyclone preheater of the suspension preheating system before entering the first cooling system. The first cooling system includes one or more cyclone coolers, a high-efficiency material spreading device, and connecting pipes. The hot material undergoes rapid cooling and gas-solid separation in the cyclone coolers of the first cooling system. After rapid cooling, the material, after gas-solid separation, enters the second cooling system through the discharge pipe of the lowest-level cyclone cooler in the first cooling system. The second cooling system includes one or more cyclone coolers, a high-efficiency material spreading device, and connecting pipes. The material undergoes further cooling and gas-solid separation in the cyclone coolers of the second cooling system, and finally exits through the discharge pipe of the lowest-level cyclone cooler in the second cooling system, falling into the finished product zipper machine to obtain the desired finished product.

[0091] In terms of gas flow direction: At-temperature air enters the second cooling system, subsequently cooling the hot material entering the system. The air, having completed heat exchange, exits from the outlet of the top-level cyclone cooler in the second cooling system. After being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). It then splits into two paths: one path enters the bottom-level cyclone cooler in the first cooling system, cooling the hot material entering the first cooling system. The air, having completed heat exchange, enters the calcining furnace system through the bottom of the preheating furnace. The flue gas formed from the combustion and decomposition of coal gangue (and fuel) in the calcining furnace system exits the calcining furnace system and enters the suspension preheating system. There, the raw material powder fed into the suspension preheating system undergoes multiple preheating and gas-solid separation processes, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system.

[0092] The other air supply has two different design schemes. In the first scheme, the other air is treated by the flue gas treatment system before being discharged into the atmosphere. In the second scheme (which also applies when the raw material is coal gangue with low calorific value), the other air enters the outlet of the lowest-level cyclone preheater in the suspension preheating system or the outlet pipe of the calcining furnace to cool the flue gas temperature. Then, it performs multiple preheating and gas-solid separation processes on the raw material powder fed into the suspension preheating system, and finally leaves from the outlet of the highest-level cyclone preheater in the suspension preheating system. After that, it enters the waste heat recovery system for waste heat recovery and utilization, and is then treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere.

[0093] Furthermore, the flue gas exits from the outlet of the top-level cyclone preheater of the suspension preheating system, then enters the waste heat recovery system for waste heat recovery and utilization, and is then discharged into the atmosphere after being treated by the dust collection system and the flue gas treatment system.

[0094] Example 9

[0095] In terms of material flow, kaolinite-containing coal gangue raw material first enters the drying and crushing mill, where it undergoes drying and crushing to obtain raw material powder that meets production requirements. Simultaneously, the raw material powder is fed into the suspension preheating system via feeding devices from feeding points C2 to C1 (denoted as feeding point A) and C3 to C2 (denoted as feeding point B). The suspension preheating system includes a multi-stage cyclone preheater, a high-efficiency spreading device, and connecting pipes. The raw material powder undergoes preheating and gas-solid separation within the cyclone preheater. After heat exchange and gas-solid separation, the raw material powder enters the calcining furnace system through the discharge pipe of the penultimate stage cyclone preheater in the suspension preheating system. The calcining furnace system includes a high-efficiency spreading device, a hot air inlet pipe, a preheating furnace, a first burner located in the cone section of the preheating furnace, a modification furnace, a second burner located in the cone section of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe. Multiple temperature measuring points are set up in layers along the height of the preheating furnace and the modification furnace to monitor the temperature distribution inside the preheating furnace and the modification furnace in real time. By adjusting the amount of fuel and material fed into the preheating furnace and the modification furnace, the temperature distribution inside the preheating furnace and the modification furnace is controlled within a reasonable range. The reasonable temperature distribution inside the preheating furnace and the modification furnace can ensure the complete combustion of coal gangue (and fuel) and the complete decomposition of coal gangue (when the calorific value of coal gangue is within the applicable range, the heat contained in it can meet the heat requirements for the decomposition of kaolinite in coal gangue, without the need to add extra fuel or only a small amount of fuel is needed, which is the complete combustion of coal gangue; in other cases, it is the complete combustion of fuel and coal gangue). At the same time, it ensures that the coal gangue is not overburned, and the activity of the finished product relative to kaolinite meets the requirements of subsequent production. In the calcining furnace system, the combustion of coal gangue (and fuel) releases a large amount of heat for the decomposition of the coal gangue. The decomposed hot material leaves the calcining furnace system and then undergoes gas-solid separation with the hot flue gas in the lowest-level cyclone preheater of the suspension preheating system before entering the first cooling system. The first cooling system includes one or more cyclone coolers, a high-efficiency material spreading device, and connecting pipes. The hot material undergoes rapid cooling and gas-solid separation in the cyclone coolers of the first cooling system. After rapid cooling, the material, after gas-solid separation, enters the second cooling system through the discharge pipe of the lowest-level cyclone cooler in the first cooling system. The second cooling system includes one or more cyclone coolers, a high-efficiency material spreading device, and connecting pipes. The material undergoes further cooling and gas-solid separation in the cyclone coolers of the second cooling system, and finally exits through the discharge pipe of the lowest-level cyclone cooler in the second cooling system, falling into the finished product zipper machine to obtain the desired finished product.

[0096] In terms of gas flow direction: At-temperature air enters the second cooling system, subsequently cooling the hot material entering the system. The air, having completed heat exchange, exits from the outlet of the top-level cyclone cooler in the second cooling system. After being cleaned by a dust collector, it enters the circulating fan (the dust collected by the dust collector is treated as finished product and falls into the finished product zipper machine). It then splits into two paths: one path enters the bottom-level cyclone cooler in the first cooling system, subsequently cooling the hot material entering the first cooling system. The air, having completed heat exchange, enters the calcining furnace system through the bottom of the preheating furnace. The flue gas formed from the combustion and decomposition of coal gangue (and fuel) in the calcining furnace system exits the calcining furnace system and enters the suspension preheating system. There, the raw material powder fed into the suspension preheating system undergoes multiple preheating and gas-solid separation processes, finally exiting from the outlet of the top-level cyclone preheater in the suspension preheating system.

[0097] The other air supply is allocated differently depending on the situation. When the raw material is coal gangue with low calorific value, this other air supply is treated by the flue gas treatment system before being discharged into the atmosphere. In other cases, this other air supply enters the outlet of the lowest-level cyclone preheater in the suspension preheating system or the outlet pipe of the calcining furnace to cool the flue gas temperature. The fully cooled flue gas then preheats and separates the raw material powder fed into the suspension preheating system multiple times, finally exiting from the outlet of the highest-level cyclone preheater in the suspension preheating system.

[0098] Furthermore, the flue gas exits from the outlet of the top-level cyclone preheater of the suspension preheating system, then enters the waste heat recovery system for waste heat recovery and utilization, and is then discharged into the atmosphere after being treated by the dust collection system and the flue gas treatment system.

[0099] The other air supply has two different design schemes. In the first scheme, the other air supply is treated by the flue gas treatment system before being discharged into the atmosphere. In the second scheme (which also applies when the raw material is coal gangue with low calorific value), the other air supply enters the outlet of the lowest-level cyclone preheater in the suspension preheating system or the outlet pipe of the calcining furnace to cool the flue gas temperature. The fully cooled flue gas then preheats and separates the raw material powder fed into the suspension preheating system multiple times, and finally leaves from the outlet of the highest-level cyclone preheater in the suspension preheating system. It then enters the waste heat recovery system for waste heat recovery and utilization, and is finally discharged into the atmosphere after being treated by the dust collection system and the flue gas treatment system.

[0100] In summary, the present invention provides a flexible and adjustable coal gangue suspension calcination production system and method in which the combustion heat release and decomposition processes of coal gangue both occur within the calcination furnace system.

[0101] The above embodiments provide a detailed description of the present invention, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention. The preparation system and method proposed in this invention are also applicable to raw materials such as carbide slag and limestone powder containing calorific value.

Claims

1. A flexible and adjustable coal gangue suspension calcination production system, characterized in that: The flexible and adjustable coal gangue suspension calcination production system includes a suspension preheating system, a calcination furnace system, and a cooling system connected in sequence. The suspension preheating system has three stages. The suspension preheating system is equipped with a second-stage cyclone preheater to the feeding point of the first-stage cyclone preheater, or / and a third-stage cyclone preheater to the feeding point of the second-stage cyclone preheater. Depending on the feeding point, the suspension preheating system can be switched to two-stage or three-stage operation. The number of preheater stages, feeding points, and different feeding ratios can be adjusted according to actual production, so that the combustion heat release and decomposition process of coal gangue all occur within the calcining furnace system. The cooling system includes a first cooling system and a second cooling system. When the second cooling system is directly connected to the suspension preheating system, after the air leaves the outlet of the uppermost cyclone cooler of the second cooling system, one of the air streams enters the outlet of the penultimate cyclone preheater of the suspension preheating system or the outlet pipe of the calcining furnace. When the second cooling system is not directly connected to the suspension preheating system, the excess air coefficient of the flue gas at the outlet of the calcining furnace system is controlled to be 1.05~1.

20.

2. The flexible and adjustable coal gangue suspension calcination production system according to claim 1, characterized in that: The calcination furnace system includes a preheating furnace and a modification furnace. The feed pipe of the penultimate cyclone preheater of the suspension preheating system is connected to the feed inlets of the preheating furnace and the modification furnace. The outlet of the calcination furnace system is connected to the air inlet of the penultimate cyclone preheater of the suspension preheating system.

3. The flexible and adjustable coal gangue suspension calcination production system according to claim 1, characterized in that: The discharge pipe of the penultimate cyclone preheater of the suspension preheating system is connected to the first cooling system, the discharge pipe of the lowest cyclone cooler of the first cooling system is connected to the second cooling system, and the discharge pipe of the lowest cyclone cooler of the second cooling system is connected to the finished product zipper machine.

4. The flexible and adjustable coal gangue suspension calcination production system according to claim 3, characterized in that: The air outlet pipe of the second cooling system is divided into two paths: one path connects to the air inlet of the lowest-level cyclone cooler of the first cooling system, and the other path connects to the air outlet of the lowest-level cyclone preheater of the suspension preheating system or the outlet pipe of the calcining furnace.

5. The flexible and adjustable coal gangue suspension calcination production system according to claim 3, characterized in that: The exhaust pipe of the second cooling system is divided into two paths: one path connects to the air inlet of the lowest-level cyclone cooler of the first cooling system, and the other path is discharged into the atmosphere after being treated by the flue gas treatment system.

6. The flexible and adjustable coal gangue suspension calcination production system according to claim 3, characterized in that: The air outlet duct of the second cooling system is divided into two paths. One path connects to the air inlet of the lowest-level cyclone cooler of the first cooling system, and the other path is further divided into two paths, each equipped with a valve. One path connects to the air outlet of the lowest-level cyclone preheater of the suspension preheating system or the outlet duct of the calcining furnace, and the other path connects to the atmosphere.

7. The flexible and adjustable coal gangue suspension calcination production system according to claim 1, characterized in that: The suspension preheating system includes a multi-stage cyclone preheater, a high-efficiency material spreading device, and connecting pipes; the calcining furnace system also includes a high-efficiency material spreading device, a hot air inlet pipe, a first burner arranged in the cone of the preheating furnace, a second burner arranged in the cone of the modification furnace, a third burner in the middle of the modification furnace, and a flue gas outlet pipe; multiple temperature measuring points are arranged in layers along the height direction of the preheating furnace and the modification furnace; the first cooling system includes one or more stages of cyclone coolers, a high-efficiency material spreading device, and connecting pipes; the second cooling system includes one or more stages of cyclone coolers, a high-efficiency material spreading device, and connecting pipes.

8. The flexible and adjustable coal gangue suspension calcination production system according to claim 1, characterized in that: The first cooling system has one to four stages of cyclone coolers; the second cooling system has one to four stages of cyclone coolers; the calcination temperature in the calcination furnace system is 650 to 1000℃; the residence time of the gas in the calcination furnace system is 2 to 10 seconds; and the outlet flue gas temperature of the calcination furnace system is 700 to 850℃.

9. A flexible and adjustable coal gangue suspension calcination production process, characterized in that: The flexible and adjustable coal gangue suspension calcination production process includes the following material flow direction and gas flow direction: Material flow: Coal gangue raw material powder is fed into the second-stage cyclone preheater of the suspension preheating system via a feeding device to the feeding point of the first-stage cyclone preheater, or / and the third-stage cyclone preheater to the feeding point of the second-stage cyclone preheater. After heat exchange and gas-solid separation, it enters the calcining furnace system. In the calcining furnace system, the coal gangue and / or fuel combustion releases a large amount of heat for the decomposition of coal gangue. The decomposed hot material leaves the calcining furnace system and then enters the first cooling system after gas-solid separation with the hot flue gas in the lowest-stage cyclone preheater of the suspension preheating system. The hot material achieves rapid cooling and gas-solid separation in the cyclone cooler of the first cooling system. The material after rapid cooling in the first cooling system enters the second cooling system through the discharge pipe of the first cooling system. The material further achieves cooling and gas-solid separation in the cyclone cooler of the second cooling system and finally leaves from the discharge pipe of the lowest-stage cyclone cooler of the second cooling system. Gas flow direction: ambient temperature air enters the second cooling system and cools the hot material entering the second cooling system. The air that has completed heat exchange leaves from the outlet of the top cyclone cooler of the second cooling system and then splits into two paths: one path enters the inlet of the bottom cyclone cooler of the first cooling system and cools the hot material entering the first cooling system. The air that has completed heat exchange enters the calcining furnace system through the bottom of the preheating furnace. The flue gas formed by the combustion of coal gangue and / or fuel and the decomposition of coal gangue leaves the calcining furnace system and enters the suspension preheating system. The raw material powder fed into the suspension preheating system is then preheated and gas-solid separated multiple times, and finally leaves from the outlet of the top cyclone preheater of the suspension preheating system. The other air supply has two different scenarios. In the first scenario, the other air supply is treated by the flue gas treatment system and then discharged into the atmosphere. In the second scenario, the other air supply enters the outlet of the lowest-level cyclone preheater in the suspension preheating system or the outlet pipe of the calcining furnace to cool the flue gas temperature. The fully cooled flue gas then preheats and separates the raw material powder fed into the suspension preheating system multiple times, and finally leaves from the outlet of the highest-level cyclone preheater in the suspension preheating system. It then enters the waste heat recovery system for waste heat recovery and utilization, and is then treated by the dust collection system and the flue gas treatment system before being discharged into the atmosphere.

10. The flexible and adjustable coal gangue suspension calcination production process according to claim 9, characterized in that: When the raw material is coal gangue with low calorific value, the fuel used in the calcining furnace system is natural gas; the excess air coefficient of the flue gas at the outlet of the calcining furnace system is 1.05~1.20, the calorific value of the coal gangue is 200~500 kcal / kg; the combustion temperature range of the coal gangue is 350~600℃, and the intense combustion temperature range of the coal gangue is 450~550℃.

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