A static kiln cement clinker calcining system

Abstract

The present invention belongs to the technical field of static cement kiln calcining equipment, and specifically relates to a static kiln cement clinker calcining system, which includes a feed distribution and adjustment system electrically connected to a control system, a multi-stage cyclone preheating system, a secondary calcining furnace, a fluidized bed calcining furnace and a cooling system, and the room temperature raw material is discharged in the form of clinker after passing through the feed distribution and adjustment system, the multi-stage cyclone preheating system, the secondary calcining furnace, the fluidized bed calcining furnace and the cooling system in sequence, and the room temperature gas is discharged in the form of waste gas after passing through the cooling system, the fluidized bed calcining furnace, the secondary calcining furnace and the multi-stage cyclone preheating system in sequence. The present invention has the characteristics of flexibility in the calcination of cement clinker in small batches of multiple specifications, and the cooling air of the fluidized bed calcining furnace is not discharged externally. All the waste heat is recycled; due to the low calcination rate of clinker, the energy consumption is reduced, which reduces the energy consumption to a certain extent, thereby reducing environmental pollution and saving energy and protecting the environment.

Description

Technical Field

[0001] The invention belongs to the technical field of static cement kiln calcining equipment, and in particular relates to a static kiln cement clinker calcining system. Background Art

[0002] At present, the world's common cement clinker production technology adopts a new dry-process rotary kiln calcination method. The calcination process system, which is composed of suspension preheating and pre-decomposition technology and rotary kiln equipment, plays a key role in the entire cement production line. my country's new dry-process cement technology started late, but has developed rapidly, especially after 2000. The process technology level and some equipment have reached the world's advanced level, and the single-machine scale output has reached the world's leading level.

[0003] However, cement is a high-pollution, high-energy-consuming industry. In the existing cement clinker calcination process system, the calcination temperature of cement clinker reaches 1450°C, and the exhaust gas temperature discharged from the five-stage cyclone preheater is as high as 320°C or above. The high energy consumption and high pollution of the cement clinker calcination process have not changed. In addition, the existing cement clinker calcination process equipment cannot meet the needs of calcining special cements such as high-aluminum and high-iron cements. It is easy to form rings and balls in the kiln, thus affecting production. Moreover, the rotary kiln occupies a large area and has a high investment cost. The coal-fired replacement technology and exhaust gas emissions also encounter technical bottlenecks. This is the inadequacy of the existing technology. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a static kiln cement clinker calcining system in view of the deficiencies in the prior art. The present invention can not only meet the production of traditional silicate cement clinker, but also can produce fast-hardening cement clinker such as marine engineering cement clinker, nuclear power cement clinker and other high-iron and high-aluminum cement. It has the characteristics of flexible calcination of cement clinker of multiple specifications and small batches, and the cooling air of the fluidized bed calcining furnace is not discharged. All waste heat is recycled; due to the low calcination of clinker, energy consumption is reduced, energy consumption is reduced to a certain extent, thereby reducing environmental pollution and saving energy and protecting the environment.

[0005] This solution is achieved through the following technical measures: a static kiln cement clinker calcining system, which includes a feeding distribution and adjustment system, a multi-stage cyclone preheating system, a secondary calciner, a fluidized bed calciner and a cooling system electrically connected to the control system. The room temperature raw material passes through the feeding distribution and adjustment system, the multi-stage cyclone preheating system, the secondary calciner, the fluidized bed calciner and the cooling system in sequence and is discharged in the form of clinker. The room temperature gas passes through the cooling system, the fluidized bed calciner, the secondary calciner and the multi-stage cyclone preheating system in sequence and is discharged in the form of waste gas.

[0006] Preferably, the fluidized bed calcining furnace is supplied with fuel by direct supply of pulverized coal or gas, or the gasification furnace indirectly burns organic solid waste, hazardous waste and biomass to supply combustible gas, or a combination of the two methods.

[0007] Preferably, the temperature of the clinker discharged from the cooling system is ≤150°C, and the temperature of the exhaust gas discharged from the multi-stage cyclone preheating system is ≤260°C.

[0008] Preferably, the calcination temperature in the fluidized bed calcining furnace is 1300° C.-1350° C., and the material is calcined in a fluidized state to instantly form cement silicate minerals into 1-5 mm spherical clinker particles.

[0009] Preferably, the feeding distribution and adjustment system is connected to the raw material system and the multi-stage cyclone preheating system, and the feeding distribution and adjustment system includes a screw conveyor and more than two grid wheel feeders, and the control system automatically adjusts the feeding amount of the grid wheel feeder in real time according to the temperature and pressure parameters of the multi-stage cyclone preheating system.

[0010] Preferably, the number of the multi-stage cyclone preheating systems is equal to the number of the dividing wheel feeders, and the multi-stage cyclone preheating system includes a plurality of cyclone separators connected in sequence. The multi-stage cyclone preheating system is used to make the room-temperature raw meal passing through each cyclone separator exchange heat with the high-temperature gas in the cyclone separator step by step to preheat the raw meal, and preheat the room-temperature raw meal to 800℃-900℃. The high-temperature raw meal exiting the multi-stage cyclone preheating system enters the secondary calcining furnace.

[0011] Preferably, the secondary calcining furnace is located between the fluidized bed calcining furnace and the multi-stage cyclone preheating system and is connected to both. The secondary calcining furnace calcines the raw meal by secondary fuel supply and heating, so that silicate minerals required for cement clinker in the raw meal are initially formed.

[0012] Preferably, a porous tower-shaped grate bed is rotatably installed at the bottom of the inner cavity of the fluidized bed calciner, and a cavity is provided below the tower-shaped grate bed which is connected to an air supply pipe. A vertical strip-shaped crushing tooth 1 is arranged around the tower-shaped grate bed, and a circle of vertical strip-shaped crushing teeth 2 corresponding to the position of the vertical strip-shaped crushing teeth 1 is arranged on the inner cylinder wall of the furnace body of the fluidized bed calciner, and a gap is left between the vertical strip-shaped crushing teeth 1 and the vertical strip-shaped crushing teeth 2 for clinker to pass through. The vertical strip-shaped crushing teeth 1 and the vertical strip-shaped crushing teeth 2 cooperate to crush the coked clinker, so that the fired clinker particles fall into the cooling system from the gap between the vertical strip-shaped crushing teeth 1 and the vertical strip-shaped crushing teeth 2 under the action of gravity, and the hot air in the fluidized bed calciner successively enters the secondary calciner and the multi-stage cyclone preheating system.

[0013] Preferably, the cooling system comprises a quenching chamber and a cooler, the quenching chamber is located at the bottom of the fluidized bed calciner and is connected to the fluidized bed calciner, and the feed inlet of the cooler is connected to the discharge outlet of the quenching chamber.

[0014] Preferably, the quenching chamber is connected to an air duct, and a cooling coil is installed in the quenching chamber. The room temperature gas introduced from the air duct is used as cooling air. The cooling air is in direct contact with the clinker to directly cool the clinker. The cooling medium in the cooling coil performs heat exchange cooling with the clinker to indirectly cool the clinker, thereby achieving rapid cooling of the clinker and reducing the temperature of the clinker to below 600°C. The cooler further cools the clinker after being cooled in the quenching chamber to reduce the temperature of the clinker to below 150°C.

[0015] Beneficial effects of the present invention:

[0016] 1. In the present invention, due to the heat of the gas itself entering the fluidized bed calciner from the cooling system, the combustion in the fluidized bed calciner is easier to carry out, the fuel burns fully, the combustion efficiency is high, the clinker is fully and quickly calcined in the fluidized bed calciner by fluidization, and the SiO2, Fe2O3, and Al2O3 in the clinker instantly form a liquid phase at high temperature, and a phase reaction occurs to form cement minerals C3S\C2S\C3A\C4AF, forming clinker particles of 1-5mm, and the maximum firing temperature is 1350°C, which is 100°C lower than the existing production process, which is beneficial to energy saving, and the firing time of the clinker is short, which is beneficial to energy saving;

[0017] 2. The cement clinker burning equipment in the present invention is stationary and occupies a small area. The fluidized bed calcining furnace in the present invention can replace the rotary kiln in the prior art which occupies a large area.

[0018] 3. The clinker discharged from the fluidized bed calcining furnace in the present invention is cooled by air cooling and water cooling, so that the heat recovery efficiency of the product reaches more than 90%, and there is no residual wind emission, which reduces environmental pollution, saves energy and is environmentally friendly. The wind temperature out of the multi-stage cyclone preheating system is below 260°C, which is about 50°C lower than the existing rotary kiln production process.

[0019] It can be seen that compared with the prior art, the present invention has outstanding substantive features and remarkable technological progress, and the beneficial effects of its implementation are also obvious. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of a specific implementation mode of the present invention.

[0021] Figure 2 It is a flowchart of the operation process of a specific implementation mode of the present invention.

[0022] Figure 3 This is a schematic diagram of the installation structure of the tower grate bed in the fluidized bed calcining furnace.

[0023] Figure 4 It is a schematic diagram of the top view of the tower grate bed structure.

[0024] In the figure: 1-raw material system, 2-feeding distribution and adjustment system, 21-screw conveyor, 22-grid wheel feeder, 3-multi-stage cyclone preheating system, 31-cyclone separator, 4-secondary calcining furnace, 5-fluidized bed calcining furnace, 51-tower grate bed, 52-vertical strip crushing tooth 2, 53-vertical strip crushing tooth 1, 6-quenching chamber, 7-cooling machine, 71-grate bed. DETAILED DESCRIPTION

[0025] In order to clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods and in conjunction with the accompanying drawings.

[0026] A static kiln cement clinker calcining system, which includes a feed distribution adjustment system 2 electrically connected to a control system, a multi-stage cyclone preheating system 3 ( Figure 1 Shown in the figure is a five-stage cyclone preheating system consisting of C1-C5), a secondary calciner 4, a fluidized bed calciner 5 and a cooling system. The room temperature raw material passes through the feeding distribution and adjustment system 2, the multi-stage cyclone preheating system 3, the secondary calciner 4, the fluidized bed calciner 5 and the cooling system in sequence and is discharged in the form of clinker. The room temperature gas passes through the cooling system, the fluidized bed calciner 5, the secondary calciner 4 and the multi-stage cyclone preheating system 3 in sequence and is discharged in the form of waste gas. The temperature of the clinker discharged from the cooling system is ≤150°C, and the temperature of the waste gas discharged from the multi-stage cyclone preheating system 3 is ≤260°C.

[0027] The feeding distribution and adjustment system 2 is connected to the raw material system 1 and the multi-stage cyclone preheating system 3. The feeding distribution and adjustment system 2 includes a screw conveyor 21 and more than two grid wheel feeders 22 ( Figure 1 As shown in the figure, two grid wheel feeders 22 are provided. The raw material is transported to the grid wheel feeders 22 through the screw conveyor 21, and then transported to the corresponding multi-stage cyclone preheating system 3 through each grid wheel feeder 22. The control system automatically adjusts the feeding amount of the grid wheel feeder 22 in real time according to the temperature and pressure parameters of the multi-stage cyclone preheating system 3. When the temperature of the multi-stage cyclone preheating system 3 increases and the pressure decreases, the feeding amount of the grid wheel feeder 22 increases. When the temperature of the multi-stage cyclone preheating system 3 decreases and the pressure increases, the feeding amount of the grid wheel feeder 22 decreases, thereby ensuring that the air volume, pressure and temperature of the feeding distribution and adjustment system 2 and the raw material system 1 are balanced.

[0028] The number of the multi-stage cyclone preheating systems 3 is equal to the number of the grid wheel feeders 22. The multi-stage cyclone preheating system 3 includes a plurality of cyclone separators 31 connected in sequence. The multi-stage cyclone preheating system 3 is used to allow the room-temperature raw material passing through each cyclone separator 31 to exchange heat with the high-temperature gas in the cyclone separator 31 step by step to preheat the raw material. The room-temperature raw material is preheated to 800°C-900°C, and the high-temperature raw material exiting the multi-stage cyclone preheating system 3 enters the secondary calcining furnace 4. Among them, the raw material and the high-temperature gas exchange heat. Under the action of the centrifugal force inside the cyclone separator 31, the raw material collides with the outer volute of the cyclone separator 31 and then falls into the ash collecting hopper, and then enters the next-stage cyclone separator 31 through the ash collecting hopper to perform the next-stage heat exchange and gas-solid separation, thereby realizing the step-by-step heat exchange of the raw material, preheating the room temperature raw material to 800°C ~ 900°C, and the hot air after leaving the multi-stage cyclone preheating system 3 enters the secondary calcining furnace 4 to exchange heat with the raw material.

[0029] The secondary calcining furnace 4 is located between the fluidized bed calcining furnace 5 and the multi-stage cyclone preheating system 3 and is connected to the two. The secondary calcining furnace 4 calcines the raw material by secondary fuel supply and heating, so that the silicate minerals required for cement clinker in the raw material are initially formed, and then the raw material enters the fluidized bed calcining furnace 5 for further calcination under a boiling fluidized state.

[0030] The fuel supply of the fluidized bed calciner 5 is a direct supply of pulverized coal or gas, or a gasification furnace that indirectly burns organic solid waste, hazardous waste and biomass to supply combustible gas, or a combination of the two. Specifically, pulverized coal is directly supplied to the fluidized bed calciner 5 by a pneumatic conveying pump coal feeding system, and the gas is directly sprayed into the fluidized bed calciner 5. The offline gasification furnace produces high-temperature combustible gas to supply fuel to the fluidized bed calciner 5, realizing coal substitution.

[0031] A porous tower grate bed 51 is rotatably installed at the bottom of the inner cavity of the fluidized bed calcining furnace 5. There is a cavity below the tower grate bed 51 connected to an air supply pipe, which is connected to a high-pressure fan. The high-pressure fan directly supplies air through the air supply pipe, which plays the role of fluidizing air and fuel combustion oxygen supply. The periphery of the tower grate bed 51 is provided with a vertical strip crushing tooth 1 53. The inner wall of the furnace body of the fluidized bed calcining furnace 5 is provided with a circle of vertical strip crushing teeth 2 52 corresponding to the position of the vertical strip crushing teeth 1 53. A gap is left between the vertical strip crushing teeth 1 53 and the vertical strip crushing teeth 2 52 for clinker to pass through. The vertical strip crushing teeth 1 53 and the vertical strip crushing teeth 2 52 cooperate to crush the coked clinker, which plays a crushing role when the material is coked to avoid the jamming of large particles. The calcination temperature in the fluidized bed calcining furnace 5 is 1300°C-1350°C, which is about 100°C lower than that of the traditional rotary kiln. The material is calcined in a fluidized state, and cement silicate minerals are instantly formed into 1-5mm spherical clinker particles. The calcined clinker particles fall into the cooling system from the gap between the vertical strip crushing teeth 1 53 and the vertical strip crushing teeth 2 52 under the action of gravity. The hot air in the fluidized bed calcining furnace 5 enters the secondary calcining furnace 4 and the multi-stage cyclone preheating system 3 in turn.

[0032] The cooling system includes a quenching chamber 6 and a cooler 7. The quenching chamber 6 is located at the bottom of the fluidized bed calcining furnace 5 and is connected to the fluidized bed calcining furnace 5. The feed port of the cooler 7 is connected to the discharge port of the quenching chamber 6. The quenching chamber 6 is connected to an air duct, and a cooling coil is installed in the quenching chamber 6. The normal temperature gas introduced from the air duct is used as cooling air. The cooling air is in direct contact with the clinker to directly cool the clinker. The cooling medium in the cooling coil performs heat exchange cooling with the clinker to indirectly cool the clinker, so that the clinker is quickly cooled and the temperature of the clinker is reduced to below 600°C. The cooler 7 further cools the clinker after being cooled in the quenching chamber 6 to reduce the temperature of the clinker to below 150°C. Among them, the grate bed 71 of the cooler 7 is mechanically driven or hydraulically driven, and the grate bed 71 pushes the clinker from the feed end to the discharge end.

[0033] The present invention has the advantages that:

[0034] 1. Advantages of calcination technology:

[0035] (a) The fuel burns fully and the combustion efficiency is high;

[0036] (b) There are multiple heat exchange modes with high heat exchange efficiency: the fluidized bed calcining furnace 5 has both direct conduction and convection heat transfer in the furnace, ensuring that the heat is fully utilized;

[0037] (c) Low calcination temperature, low exhaust gas temperature, and less surface heat dissipation: The calcination temperature in the fluidized bed calciner 5 is only 1300-1350°C, which is 100°C lower than that of an ordinary rotary kiln;

[0038] (d) The calcination environment in the fluidized bed calcination furnace 5 is uniform and controllable, and no under-burning or over-burning occurs.

[0039] 2. Technical advantages of process flow:

[0040] The temperature of the gas after combustion in the fluidized bed calciner 5 rises to 1300℃~1350℃, and enters the secondary calciner 4, and then enters the multi-stage cyclone preheating system 3, and is reversed to the raw material entering the multi-stage cyclone preheating system 3. The room temperature raw material is preheated to 800℃~900℃ step by step through the multi-stage cyclone preheating system 3, and the preheated high-temperature raw material is further calcined in the secondary calciner 4 and the fluidized bed calciner 5, and finally cooled by the cooling system. The hot air after cooling the clinker returns to the fluidized bed calciner 5, realizing full recovery and utilization of heat. The multi-stage cyclone preheating system 3 realizes the preheating of raw materials in a suspended state, so that the heat exchange of raw materials is more sufficient, and the exhaust gas temperature of the multi-stage cyclone preheating system 3 drops below 260℃, which can be further utilized. Compared with the existing rotary kiln calcination, the present invention has low energy consumption, less heat loss, and is more beneficial to energy saving.

[0041] Compared with the existing grate cooler, the cooling system of the present invention uses less air volume and has low equipment wear. In addition, part of the hot air of the existing grate cooler is discharged at the kiln head, resulting in heat energy loss. In the present invention, the cooling air of the fluidized bed calcining furnace 5 is fully recycled, which not only improves the thermal efficiency, but also eliminates the exhaust of residual air and reduces environmental pollution.

[0042] 3. Advantages of energy consumption and emission indicators of the present invention:

[0043] The present invention can produce 1000-5000 tons of Portland cement clinker per day;

[0044] Clinker heat consumption: 2909KJ / Kg-cli, clinker burning system power consumption: 39kwh / kg-cli. The low energy consumption of the present invention is 690kcal / kg, which is 10% lower than that of the rotary kiln.

[0045] The present invention has a wide range of coal adaptability and can utilize inferior coal and lignite. It can not only meet the production of traditional silicate cement clinker, but also can carry out small-batch production of multiple specifications such as oil well cement clinker, offshore cement clinker, nuclear power cement clinker, etc. It has the characteristics of flexibility in the production of multiple specifications and small-batch cement clinker.

[0046] The present invention can achieve low CO2 emission, which is 10-25% lower than the existing normal cement kiln, and can also achieve low NO x Emissions, NOx 40% lower than existing normal cement kilns x Emissions.

[0047] The clinker product of the invention has high quality and is 10MPa stronger than the existing rotary kiln clinker.

[0048] In the present invention, a composite cooling method combining air cooling and water cooling is adopted for the hot air discharged from the fluidized bed calcining furnace 5, so that the heat recovery efficiency of the product reaches more than 90%.

[0049] Technical features not described in the present invention can be implemented by existing technologies and will not be described in detail here. The present invention is not limited to the above specific embodiments, and changes, modifications, additions or substitutions made by ordinary technicians in the field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A static kiln cement clinker calcining system, characterized in that: It includes a feed distribution and adjustment system, a multi-stage cyclone preheating system, a secondary calciner, a fluidized bed calciner and a cooling system electrically connected to a control system. Normal temperature raw materials are discharged in the form of clinker after passing through the feed distribution and adjustment system, the multi-stage cyclone preheating system, the secondary calciner, the fluidized bed calciner and the cooling system in sequence. Normal temperature gas is discharged in the form of waste gas after passing through the cooling system, the fluidized bed calciner, the secondary calciner and the multi-stage cyclone preheating system in sequence. The fuel supply of the fluidized bed calciner is a direct supply of coal powder or gas, or an indirect combustion of organic solid waste, hazardous waste and biomass in a gasification furnace to supply combustible gas, or a combination of the two methods; The temperature of the clinker discharged from the cooling system is ≤150℃, and the temperature of the exhaust gas discharged from the multi-stage cyclone preheating system is ≤260℃; A porous tower-shaped grate bed is rotatably installed at the bottom of the inner cavity of the fluidized bed calcining furnace, and a cavity is provided below the tower-shaped grate bed and is connected to an air supply pipe. A vertical strip crushing tooth 1 is arranged around the tower-shaped grate bed, and a circle of vertical strip crushing teeth 2 corresponding to the position of the vertical strip crushing teeth 1 is arranged on the inner cylinder wall of the furnace body of the fluidized bed calcining furnace, and a gap for clinker to pass through is reserved between the vertical strip crushing teeth 1 and the vertical strip crushing teeth 2. The vertical strip crushing teeth 1 and the vertical strip crushing teeth 2 cooperate to crush the coked clinker, so that the burned clinker particles fall into the cooling system from the gap between the vertical strip crushing teeth 1 and the vertical strip crushing teeth 2 under the action of gravity, and the hot air in the fluidized bed calcining furnace enters the secondary calcining furnace and the multi-stage cyclone preheating system in turn; The feeding distribution and adjustment system is connected with the raw material system and the multi-stage cyclone preheating system. The feeding distribution and adjustment system includes a screw conveyor and more than two grid wheel feeders. The control system automatically adjusts the feeding amount of the grid wheel feeder in real time according to the temperature and pressure parameters of the multi-stage cyclone preheating system; when the temperature of the multi-stage cyclone preheating system increases and the pressure decreases, the feeding amount of the grid wheel feeder increases; when the temperature of the multi-stage cyclone preheating system decreases and the pressure increases, the feeding amount of the grid wheel feeder decreases, so as to ensure the balance of air volume, pressure and temperature of the feeding distribution and adjustment system and the raw material system.

2. The static kiln cement clinker calcining system according to claim 1 is characterized in that: The calcination temperature in the fluidized bed calcining furnace is 1300° C.-1350° C. The material is calcined in a fluidized state, and cement silicate minerals are instantly formed into 1-5 mm spherical clinker particles.

3. The static kiln cement clinker calcining system according to claim 2 is characterized in that: The number of the multi-stage cyclone preheating systems is equal to the number of the grid wheel feeders. The multi-stage cyclone preheating system includes a plurality of cyclone separators connected in sequence. The multi-stage cyclone preheating system is used to make the room-temperature raw materials passing through each cyclone separator exchange heat with the high-temperature gas in the cyclone separator step by step to preheat the raw materials. The room-temperature raw materials are preheated to 800°C-900°C. The high-temperature raw materials leaving the multi-stage cyclone preheating system enter the secondary calcining furnace.

4. The static kiln cement clinker calcining system according to claim 3 is characterized in that: The secondary calcining furnace is located between the fluidized bed calcining furnace and the multi-stage cyclone preheating system and is connected to the two. The secondary calcining furnace calcines the raw material by secondary fuel supply and heating, so that the silicate minerals required for cement clinker in the raw material are initially formed.

5. The static kiln cement clinker calcining system according to claim 4 is characterized in that: The cooling system comprises a quenching chamber and a cooler. The quenching chamber is located at the bottom of the fluidized bed calcining furnace and is communicated with the fluidized bed calcining furnace. The feed port of the cooler is communicated with the discharge port of the quenching chamber.

6. The static kiln cement clinker calcining system according to claim 5 is characterized in that: The quenching chamber is connected to an air duct, and a cooling coil is installed in the quenching chamber. The room temperature gas introduced from the air duct is used as cooling air. The cooling air is in direct contact with the clinker to directly cool the clinker. The cooling medium in the cooling coil performs heat exchange cooling with the clinker to indirectly cool the clinker, thereby achieving rapid cooling of the clinker and reducing the temperature of the clinker to below 600°C. The cooler further cools the clinker after being cooled in the quenching chamber to reduce the temperature of the clinker to below 150°C.

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