Method for transforming cement clinker production line into coal gangue suspension calcination production line

Abstract

The invention belongs to the technical field of cement production line transformation, and discloses a method for transforming a cement clinker production line into a coal gangue suspension calcination production line, the cement clinker production line comprises five stages of double-series preheaters and a decomposing furnace, the five stages of double-series preheaters are divided into A-row preheaters and B-row preheaters, a preheater in the column A is transformed into a preheating device of the coal gangue powder suspension calcination production line, a preheater in the column B is transformed into a gas-solid separation cyclone and a cooling device of the coal gangue powder suspension calcination production line, and a pipeline furnace is arranged between an air outlet of a decomposing furnace and an air inlet of the gas-solid separation cyclone. A decomposing furnace and a pipeline furnace are jointly transformed into a coal gangue suspension calcining furnace. According to the method, an obsolete cement clinker production line is transformed into a coal gangue suspension calcining production line with the working procedures of coal gangue grinding, conveying, metering, preheating, calcining, cooling and the like.

Description

Technical Field

[0001] This invention relates to a process for converting a new dry-process cement production line that eliminates outdated production capacity into a powdered calcined coal gangue production line. Specifically, it relates to a method for converting a new dry-process cement production line with a five-stage preheater into a coal gangue suspension calcination production line. Background Technology

[0002] In response to the declining demand for cement from downstream industries, and to further reduce energy consumption and pollutant emissions in the cement industry, a number of small-scale, technologically outdated cement clinker production lines are about to be phased out due to environmental protection needs. Dismantling all of these lines would result in a significant waste of equipment resources. New dry-process cement production lines typically involve two thermal processes: raw cement meal calcination and clinker calcination. Coal gangue suspension calcination primarily uses a suspension calcination furnace to disperse and calcine coal gangue powder, which shares a similar suspension thermal process with the decomposition furnace in the cement industry.

[0003] In the prior art, patent CN118442813A discloses a method and system for coupling coal gangue calcination with cement production. Specifically, a coal gangue calcination and cooling system is built next to the kiln tail system of the cement production line. Except for a portion of the tertiary air from the cement kiln system being sent to the coal gangue calcination system and the flue gas from the coal gangue calcination system being sent to the cement kiln preheater system, the coal gangue calcination system is built with a separate frame. The cement kiln system and the coal gangue calcination system operate synchronously. However, the coal gangue processing capacity is limited by the amount of waste gas generated by the cement kiln system and the coal gangue calcination.

[0004] Therefore, there is an urgent need for a method to transform a cement clinker production line into a coal gangue suspension calcination production line. This method would make full use of the existing equipment in the original cement clinker production line and transform it into a production line that meets the requirements of the coal gangue suspension calcination process. This would not only satisfy the requirements of the coal gangue suspension calcination process but also significantly reduce the high investment costs of building new suspension calcination production lines. Summary of the Invention

[0005] In view of the characteristics of new dry process cement production lines and the requirements of coal gangue suspension calcination process, this invention provides a method for transforming a cement clinker production line into a coal gangue suspension calcination production line, which transforms outdated cement clinker production lines into coal gangue suspension calcination production lines with processes such as coal gangue grinding, conveying, metering, preheating, calcination and cooling.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: A method for converting a cement clinker production line into a coal gangue suspension calcination production line, wherein the cement clinker production line includes a five-stage dual-series preheater and a decomposition furnace, the five-stage dual-series preheater being divided into an A-row preheater and a B-row preheater, the A-row preheater being converted into a preheating device for the coal gangue powder suspension calcination production line, the B-row preheater being converted into a gas-solid separation cyclone and cooling device for the coal gangue powder suspension calcination production line, and a pipeline furnace being installed between the air outlet of the decomposition furnace and the air inlet of the gas-solid separation cyclone furnace, thereby converting the decomposition furnace and the pipeline furnace together into a coal gangue suspension calcination furnace.

[0007] Furthermore, the A-column preheater includes A-1 cyclone, A-2 cyclone, A-3 cyclone, A-4 cyclone, and A-5 cyclone, and the B-column preheater (8) includes B-1 cyclone, B-2 cyclone, B-3 cyclone, B-4 cyclone, and B-5 cyclone; remove the A-5 cyclone of the A-column preheater, the B-1 cyclone of the B-column preheater, and the corresponding air outlet pipes, and remove the A-1 cyclone, A-2 cyclone, and A-3 cyclone. The preheating device is composed of cyclone separators A-4 connected in series, and is respectively configured as a primary preheating device, a secondary preheating device, a tertiary preheating device, and a quaternary preheating device. The cyclone separator B-2 of the B-row preheater is modified into the gas-solid separation cyclone separator. The cyclone separators B-3, B-4, and B-5 of the B-row preheater are connected in series to form the cooling device, and are respectively configured as a tertiary cooling device, a secondary cooling device, and a primary cooling device.

[0008] Furthermore, the cement clinker production line also includes a smoke chamber, a rotary kiln, a cooler, and a tertiary air duct. The lower cone of the decomposition furnace is disconnected from the smoke chamber, and the tertiary air duct is disconnected from the decomposition furnace. The tertiary air duct, smoke chamber, rotary kiln, and cooler are discarded. The lower cone of the decomposition furnace is transformed into the lower cone of the calcining furnace of a coal gangue suspension calcining furnace. The air outlet of the three-stage cooling device is connected to the lower cone of the calcining furnace through a pipeline.

[0009] Furthermore, an air heater is installed on the pipe between the air outlet of the three-stage cooling device and the lower cone of the calcining furnace.

[0010] Furthermore, the air outlet of the gas-solid separation cyclone and the air inlet of the fourth-stage preheating device are connected by a pipe; the feed pipe of the B-4 cyclone is disconnected from the decomposition furnace and modified into a feed pipe for the second-stage cooling device; a downward air inlet pipe is set at the air inlet of the B-5 cyclone and used as the air inlet pipe for the first-stage cooling device, which is connected to the atmosphere; the feed pipe of the second-stage cooling device is connected to the air inlet pipe of the first-stage cooling device, and the interface between the two is ≥2m higher than the lower edge of the air inlet of the first-stage cooling device; the feed pipe of the B-5 cyclone is disconnected from the smoke chamber and used as the feed pipe for the first-stage cooling device.

[0011] Furthermore, the lower cone of the calcining furnace has a constricted pipe structure with a constricted section wind speed of 25-35 m / s. The cross-sectional wind speed of the air inlets, inner cylinders, and outlet pipes of the three-stage cooling device, the two-stage cooling device, and the first-stage cooling device of the cooling device is ≥15 m / s. The lower edge of the air inlet of the air inlet pipe of the first-stage cooling device adopts a constricted structure with a constricted section wind speed of ≥25 m / s.

[0012] Furthermore, the cement clinker production line also includes a limestone stockpile, limestone silo, raw meal grinding system, raw meal homogenization silo, raw meal weighing scale, raw meal feeding elevator, and a first raw meal feeding chute, which are correspondingly modified to include a coal gangue stockpile, coal gangue silo, coal gangue grinding system, coal gangue powder homogenization silo, coal gangue powder weighing scale, coal gangue powder feeding elevator, and coal gangue powder feeding chute. The bottom of the coal gangue powder homogenization silo is configured with a large-angle stacking structure, and the coal gangue powder feeding elevator is equipped with a hopper cleaning device. The drying heat source for the coal gangue grinding system is the outlet flue gas of the preheating device. The cement clinker production line also includes a second raw meal feeding chute, which is removed. The cement clinker production line also includes a high-temperature fan for the cement clinker production line, which is replaced with a high-temperature fan for the coal gangue suspension calcination production line.

[0013] Furthermore, the coal gangue stockpile is equipped with a spraying device and an infrared temperature measuring device. The spraying device includes spray guns and a water spray control system. Multiple spray guns are set up and the spraying range fully covers the coal gangue stockpile. An infrared temperature measuring device is set within the spraying coverage area of ​​each spray gun. The spraying device and the infrared temperature measuring device are both monitored for temperature and automatically turned on and off by the water spray control system.

[0014] Furthermore, both the coal gangue grinding system and the coal gangue homogenization silo are equipped with explosion-proof bag dust collectors. Both the coal gangue grinding system and the coal gangue homogenization silo are equipped with CO alarms and infrared temperature alarms, and are all associated with CO2 fire extinguishing devices. If the set CO concentration and temperature values ​​are exceeded, an alarm will be automatically triggered and the CO2 fire extinguishing device will be activated.

[0015] Furthermore, the process of the coal gangue suspension calcination production line is as follows: air enters the production line through the cooling device, passes through the cooling device, the coal gangue suspension calcination furnace, the gas-solid separation cyclone (20), and the preheating device in sequence, and undergoes three processes in sequence: air heating, high-temperature flue gas formation, and high-temperature flue gas cooling. Finally, the flue gas is discharged from the flue gas outlet of the preheating device by the high-temperature fan of the coal gangue suspension calcination production line. Low-temperature coal gangue powder enters the coal gangue suspension calcination system through the preheating device, passes through the preheating device, the coal gangue suspension calcination furnace, the gas-solid separation cyclone, and the cooling device in sequence, and undergoes three processes in sequence: coal gangue powder heating, suspension calcination activation, and cooling of the calcined coal gangue powder finished product. Finally, the calcined and activated coal gangue powder finished product is discharged from the discharge pipe of the first-stage cooling device of the cooling device.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention utilizes an existing, soon-to-be-obsolete, five-stage double-series preheater dry-process cement production line, transforming it into a coal gangue suspension calcination production line. It makes full use of the existing limestone stockpile, limestone silo, raw material grinding system, raw material homogenization silo, raw material weighing scale, raw material feeding elevator, and first raw material feeding chute, converting them into equipment for coal gangue storage, grinding, homogenization, and conveying. Compared with building a new coal gangue suspension calcination production line, it saves a huge amount of construction investment.

[0017] 2. Based on the principle of suspension calcination and cooling of powdered coal gangue, this invention transforms the five-stage double-series preheater of the cement production line into a system of four-stage preheating, one-stage gas-solid separation, and three-stage cooling of coal gangue powder, and transforms the decomposition furnace into a suspension calcination furnace for coal gangue. Compared with building a new suspension calcination system for coal gangue, this invention saves a significant amount of equipment investment and makes full use of the existing equipment in the cement clinker production line.

[0018] 3. In order to avoid the mismatch between cooling air volume and preheating flue gas volume, the present invention modifies the inlet and outlet of the gas-solid separation cyclone and the air duct to achieve a reasonable air velocity and meet the requirements of suspended material and gas-solid separation.

[0019] 4. This invention modifies or replaces high-temperature fans with changes in air volume and pressure head, so that they match the flue gas volume and system resistance of the modified coal gangue suspension calcination system, thereby enabling the process fans to operate efficiently and reducing the power consumption of the system fans.

[0020] 5. In view of the fact that coal gangue generally has a certain calorific value, the present invention modifies and adds explosion-proof devices and prevents dust accumulation, so as to ensure the safety of coal gangue powder in the operation of grinding, storage and dust collection.

[0021] 6. This invention transforms the original dual-series five-stage preheater into a four-stage preheating and three-stage cooling coal gangue suspension calcination system, which is adapted to the control requirements of coal gangue calcination decomposition temperature, exhaust gas temperature, and coal gangue calcination finished product temperature. Attached Figure Description

[0022] Figure 1 This is a flowchart of the original cement clinker production line process.

[0023] Figure 2 This is a flowchart of the process flow of the modified coal gangue suspension calcination production line.

[0024] Figure 3 This is a process flow diagram of the five-stage double-series preheater kiln tail system of the original cement clinker production line.

[0025] Figure 4 This is a process flow diagram of the modified coal gangue suspension calcination system.

[0026] Figure 5 This is the modified spray system for the coal gangue stockpile.

[0027] Figure 6 This is the first set of carbon dioxide fire extinguishing devices.

[0028] Figure 7 This is the second set of carbon dioxide fire extinguishing devices.

[0029] Figure 8 This is a process flow diagram of the modified coal gangue suspension calcination system, which includes an air-heated furnace.

[0030] Among them: 1. Limestone stockpile; 2. Limestone storage facility; 3. Raw material grinding system; 4. Raw material homogenization silo; 5. Raw material feeding elevator; 6-1. First raw material feeding chute (corresponding to column A preheater); 6-2. Second raw material feeding chute (corresponding to column B preheater); 7. Preheater in column A; 7-1, A-1 cyclone separator; 7-2, A-2 cyclone separator; 7-3, A-3 cyclone separator; 7-4, A-4 cyclone separator; 7-5, A-5 cyclone separator; 8. Preheater in column B; 8-1, B-1 cyclone separator; 8-2, B-2 cyclone separator; 8-3, B-3 cyclone separator; 8-4, B-4 cyclone separator; 8-4-1, B-4 cyclone separator discharge pipe; 8-5, B-5 ​​cyclone separator; 8-5-1, B-5 ​​cyclone separator discharge pipe; 9. Decomposition furnace; 9-1. Tertiary air duct; 9-2. Lower cone section of the decomposition furnace; 10. Smoking room; 11. Rotary kiln; 12. Cooling machine; 13. Coal gangue stockpile; 13-1. Sprinkler system; 13-1-1. Water tank; 13-1-2. Water pump; 13-1-3. Water valve; 13-1-4. Spray gun; 13-1-5. Water pipe; 13-1-6. Sprinkler control system; 13-2. Infrared temperature measuring device; 14. Coal gangue storage facility; 15. Coal gangue grinding system; 16. Coal gangue powder homogenization silo; 17. Coal gangue powder feeding elevator; 18. Coal gangue powder feeding chute; 19. Preheating device; 19-1. Primary preheating device; 19-2. Secondary preheating device; 19-3. Tertiary preheating device; 19-4. Quaternary preheating device; 19-4-1. Air inlet of the quaternary preheating device; 20. Gas-solid separation cyclone separator; 20-1. Gas-solid separation cyclone separator outlet; 21. Cooling device; 21-1 Three-stage cooling device; 21-1-1 Air outlet of three-stage cooling device; 21-2 Two-stage cooling device; 21-2-1 Material discharge pipe of two-stage cooling device; 21-3 One-stage cooling device; 21-3-1 Air inlet pipe of one-stage cooling device; 21-3-2 Material discharge pipe of one-stage cooling device; 22. Coal gangue suspension calciner; 22-1. Lower cone section of calciner; 22-2. Tube furnace; 23-1. High-temperature blower for cement clinker production line; 23-2. High-temperature blower for coal gangue suspension calcination production line; 24. CO2 fire extinguishing system; 24-1. First set of CO2 fire extinguishing system; 24-1-1. First set of carbon dioxide storage cylinders; 24-1-2. First set of safety valves; 24-1-3. First set of delivery pipelines; 24-1-4. First set of release valves; 24-1-5. First set of CO2 nozzles; 24-2. Second set of CO2 fire extinguishing system; 24-2-1. Second set of carbon dioxide storage cylinders; 24-2-2. Second set of safety valves; 24-2-3. Second set of delivery pipelines; 24-2-4. Second set of release valves; 24-2-5. Second set of CO2 nozzles; 25. Air-heated furnace. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] like Figures 1-8 As shown, the implementation scheme of the method for transforming a cement clinker production line into a coal gangue suspension calcination production line according to the present invention is described in detail. The original cement clinker production line includes a limestone stockpile 1, a limestone silo 2, a raw material grinding system 3, a raw material homogenization silo 4, a raw material feeding elevator 5, a first raw material feeding chute 6-1, a second raw material feeding chute 6-2, a five-stage double-series preheater, a high-temperature fan 23-1 for the cement clinker production line, a decomposition furnace 9, a smoke chamber 10, a rotary kiln 11, and a cooler 12. The raw material homogenization silo 4 includes a raw material weighing scale. The five-stage double-series preheater is divided into an A-row preheater 7 and a B-row preheater 8, whose feeding ports are respectively connected to the first raw material feeding chute 6-1 and the second raw material feeding chute 6-2. A tertiary air duct 9-1 is provided between the cooler 12 and the decomposition furnace 9. Based on this, it is transformed into a coal gangue suspension calcination production line.

[0033] One of the renovation contents is as follows: The original limestone stockpile 1, limestone silo 2, raw meal grinding system 3, raw meal homogenization silo 4, raw meal weighing scale, raw meal feeding elevator 5, and first raw meal feeding chute 6-1 of the cement clinker production line are respectively renovated into coal gangue stockpile 13, coal gangue silo 14, coal gangue grinding system 15, coal gangue powder homogenization silo 16, coal gangue powder weighing scale, coal gangue powder feeding elevator 17, and coal gangue powder feeding chute 18.

[0034] Furthermore, a spraying device 13-1 is added to the coal gangue stockpile 13. The spraying device 13-1 has multiple spray guns 13-1-4 on the top of the coal gangue stockpile 13, and the spraying range covers the coal gangue stockpile 13. Explosion-proof devices are added to the coal gangue grinding system 15 and the coal gangue powder homogenization silo 16, the motors are replaced with explosion-proof motors, and CO2 fire extinguishing devices 24 are added. The bottom of the coal gangue powder homogenization silo 16 is set with a large-angle stacking structure to reduce powder accumulation. The coal gangue powder feeding elevator 17 is equipped with a hopper cleaning device to prevent ash accumulation. The drying heat source of the coal gangue grinding system 15 adopts the outlet flue gas of the modified preheating device 19. The inlet and outlet temperatures of the system are controlled by the regulation of the circulating air of the coal gangue grinding system 15, and the outlet temperature is controlled at 60-80℃.

[0035] Specifically, such as Figure 5 As shown, to prevent spontaneous combustion of coal gangue, a spraying device 13-1 is installed in the coal gangue stockpile 13. The spraying device 13-1 includes a water tank 13-1-1, a water pump 13-1-2, a water valve 13-1-3, a spray gun 13-1-4, a water pipe 13-1-5, and a water spraying control system 13-1-6. The water pipe 13-1-5 connects the water tank 13-1-1, the water pump 13-1-2, and the spray gun 13-1-4. Each spray gun 13-1-4 has a water valve 13-1-3 at its inlet. The water valve 13-1-3 is an electric water valve. Multiple spray guns 13-1-4 are installed, and the spray range can fully cover the coal gangue pile. Each spray gun 13-1-4 is equipped with an infrared temperature measuring device 13-2 within its spray coverage area. Both the spray device 13-1 and the infrared temperature measuring device 13-2 are monitored for temperature and automatically start spraying through the water spray control system 13-1-6. When the infrared temperature measuring device 13-2 detects that the temperature of the coal gangue pile in the corresponding range is higher than the set value, it automatically starts spraying to cool down. The water valves and spray guns in the range will act accordingly to spray and cool down the coal gangue pile to prevent spontaneous combustion.

[0036] In addition, both the coal gangue grinding system 15 and the coal gangue homogenization silo 16 are equipped with explosion-proof bag dust collectors. Both the coal gangue grinding system 15 and the coal gangue homogenization silo 16 are equipped with CO alarms and infrared temperature alarms, and are all associated with the CO2 fire extinguishing device 24. Once the set CO concentration and temperature values ​​are exceeded, the monitoring range will automatically alarm and activate the CO2 fire extinguishing device 24 in that area to eliminate safety hazards.

[0037] The CO2 fire extinguishing device 24 can be set in two sets as needed, including a first set of CO2 fire extinguishing device 24-1 and a second set of CO2 fire extinguishing device 24-2.

[0038] Specifically, such as Figure 6 As shown, the first set of CO2 fire extinguishing devices 24-1 is installed at the coal gangue grinding system 15, including the first set of carbon dioxide storage cylinders 24-1-1, the first set of safety valves 24-1-2, the first set of conveying pipelines 24-1-3, the first set of release valves 24-1-4, and the first set of CO2 nozzles 24-1-5. The first set of carbon dioxide storage cylinders 24-1-1 consists of several cylinders connected in parallel. The first set of safety valves 24-1-2 controls the opening and closing of the pipelines, and the first set of release valves 24-1-4... The release valve 24-1-4 controls the opening and closing of the first set of CO2 nozzles 24-1-5. CO2 is delivered to the dust collector, grinding system, finished product collection cyclone and other locations and equipment in the coal gangue grinding system 15 that are prone to coal gangue combustion through the first set of conveying pipes 24-1-3. When dangerous phenomena such as coal gangue powder ignition or alarms occur, the first set of release valves 24-1-4 is opened and the first set of CO2 nozzles 24-1-5 sprays CO2 to achieve carbon dioxide spray fire extinguishing.

[0039] like Figure 7 As shown, the second set of CO2 fire extinguishing devices 24-2 is installed at the coal gangue powder homogenization silo 16, including the second set of carbon dioxide storage cylinders 24-2-1, the second set of safety valves 24-2-2, the second set of conveying pipelines 24-2-3, the second set of release valves 24-2-4, and the second set of CO2 nozzles 24-2-5. The second set of carbon dioxide storage cylinders 24-2-1 consists of several cylinders connected in parallel, and the second set of safety valves 24-2-2 controls the opening and closing of the pipeline. The second set of release valves 24-2-4 controls the opening and closing of the second set of CO2 nozzles 24-2-5. CO2 is delivered through the second set of conveying pipes 24-2-3 to the coal gangue powder homogenization silo, unloading bin, dust collector and other locations and equipment in the coal powder storage and unloading section that are prone to coal gangue combustion. In case of danger or alarm, the second set of release valves 24-2-4 is opened and the second set of CO2 nozzles 24-2-5 sprays CO2 to start carbon dioxide injection fire extinguishing.

[0040] The second aspect of the renovation is to transform the original A-row preheater 7 into a preheating device 19 for the coal gangue powder suspension calcination production line, and to transform the original B-row preheater 8 into a gas-solid separation cyclone 20 and cooling device 21 for the coal gangue powder suspension calcination production line. Specifically, the cyclones of each stage of the A-row preheater 7 in the original cement clinker production line's five-stage double-series preheater are respectively designated as A-1 cyclone 7-1, A-2 cyclone 7-2, and A-3 cyclone 7 from top to bottom. -3. Cyclone 7-4 of A-4, cyclone 7-5 of A-5, and the cyclones of each stage of the preheater 8 in column B are respectively named B-1 cyclone 8-1, B-2 cyclone 8-2, B-3 cyclone 8-3, B-4 cyclone 8-4, and B-5 cyclone 8-5 from top to bottom. Remove cyclone 7-5 of column A preheater, cyclone 8-1 of column B preheater and the corresponding air outlet pipes. At the same time, remove the second raw material feeding chute. The material path from 6-2 to preheater 8 in column B; the remaining A-1 cyclone 7-1, A-2 cyclone 7-2, A-3 cyclone 7-3, and A-4 cyclone 7-4 of preheater 7 in column A are connected in series to form the preheating device 19 of the coal gangue powder suspension calcination production line, respectively denoted as the primary preheating device 19-1, secondary preheating device 19-2, tertiary preheating device 19-3, and quaternary preheating device 19 of the coal gangue powder preheating device 19; while B Cyclone 8-2 of the preheater serves as the gas-solid separation cyclone 20 in the coal gangue powder suspension calcination production line. The remaining cyclones 8-3, 8-4, and 8-5 of the preheater 8 are connected in series to form the cooling device 21 of the coal gangue powder suspension calcination production line, which respectively serve as the tertiary cooling device 21-1, secondary cooling device 21-2, and primary cooling device 21-3 of the coal gangue powder cooling device 21.

[0041] The third aspect of the renovation is to convert the original decomposition furnace 9 and the gas-solid separation cyclone 20 into a coal gangue suspension calcining furnace 22 by installing a pipe furnace 22-2 between the furnace and the inlet of the gas-solid separation cyclone 20. Specifically, the lower cone section 9-2 of the decomposition furnace 9 will be disconnected from the smoke chamber 10, and the tertiary air duct 9-1 will be disconnected from the furnace. The original tertiary air duct 9-1, smoke chamber 10, rotary kiln 11, and cooler 12 of the cement clinker production line will no longer be used. The break between the tertiary air duct 9-1 and the decomposition furnace 9 will be sealed with castable refractory. The air outlets are disconnected from the air inlets of A5 cyclone 7-5 and B5 cyclone 8-5 of the five-stage double-series preheater, respectively. The downflow pipe of the decomposition furnace 9 is removed, and the pipe between the original B-2 cyclone 8-2 and B-3 cyclone 8-3 is removed. A pipe furnace 22-2 is installed between the air outlet of the decomposition furnace 9 and the air inlet of the gas-solid separation cyclone 20. The pipe furnace 22-2 includes an upflow pipe and a downflow pipe. The original decomposition furnace 9 and the pipe furnace (22-2) together serve as the coal gangue suspension calcining furnace 22.

[0042] Furthermore, the lower cone section 9-2 of the original decomposition furnace 9 is modified to serve as the lower cone section 22-1 of the coal gangue suspension calcining furnace 22. That is, the lower cone section 9-2 of the original decomposition furnace 9 is modified into a constricted pipe with a certain straight section height, serving as the air inlet of the coal gangue suspension calcining furnace 22. The constriction height is ≥1.5m, and the wind speed at the constriction section is preferably controlled at 25-35m / s. This ensures both the sealing effect and prevents the local resistance at the constriction from being too high, thereby forming an airflow locking function. This allows the air entering the lower cone section 22-1 of the calcining furnace to have a certain wind speed, which can support the coal gangue powder in the furnace, preventing the coal gangue powder in the coal gangue suspension calcining furnace 22 from falling to the bottom.

[0043] Modification Item 4: Connect the gas-solid separation cyclone 20 and the fourth-stage preheating device 19-4 through a pipeline, and connect the third-stage cooling device 21-1 and the lower cone 22-1 of the calcining furnace through a pipeline; specifically, connect the gas-solid separation cyclone outlet 20-1 of the gas-solid separation cyclone 20 to the fourth-stage preheating device inlet 19-4-1 of the fourth-stage preheating device 19-4 through a pipeline, so that the flue gas from the gas-solid separation cyclone 20 is sent into the fourth-stage preheating device 19-4; connect the third-stage cooling device outlet 21-1-1 of the cooling device 21 to the lower cone 22-1 of the coal gangue suspension calcining furnace 22 through a pipeline, so that high-temperature oxygen-containing gas is sent into the coal gangue suspension calcining furnace 22. If the space between the lower cone 22-1 of the calcining furnace and the smoke chamber 10 is insufficient, the smoke chamber can be partially or completely removed to ensure the space for pipeline connection.

[0044] In addition, an air heater 25 is installed between the air outlet 21-1-1 of the three-stage cooling device 21 and the lower cone 22-1 of the coal gangue suspension calcining furnace 22. The gas temperature entering the lower cone 22-1 of the calcining furnace is increased by heating through fuel combustion or indirect heating, which helps the coal gangue powder to be calcined quickly and efficiently in the suspension calcining furnace 22.

[0045] Fifthly, the design of the secondary cooling device's feed pipe 21-2-1, the primary cooling device's air inlet pipe 21-3-1, and the primary cooling device's feed pipe 21-3-2 will be modified. Specifically, the feed pipe 8-4-1 of the original B-4 cyclone will be disconnected from the decomposition furnace 9 and used as the feed pipe 21-2-1 of the secondary cooling device 21-2 of the cooling device 21. A section of air inlet pipe will be installed downwards from the air inlet of the original B-5 cyclone 8-5 as the primary cooling device's air inlet pipe 21-3-1. The primary cooling device's air inlet pipe 21-3-1 will be connected to the atmosphere. The lower edge of the air inlet pipe 21-3-1 of the primary cooling device is located below the secondary cooling device discharge pipe 21-2-1 of the secondary cooling device 21-2. The secondary cooling device discharge pipe 21-2-1 is connected to the air inlet pipe 21-3-1 of the primary cooling device. The discharge pipe 8-5-1 of the original B-5 cyclone is disconnected from the smoke chamber 10 and used as the discharge pipe 21-3-2 of the primary cooling device 21-3 of the cooling device 21. A finished product conveying system for calcined coal gangue powder is set below it to send the calcined coal gangue powder discharged from the primary cooling device 21-3 into the finished product conveying system.

[0046] Typically, before the modification, the preheaters of series A 7 and series B 8 were of the same size at each stage. After the modification, because the amount of air entering the cooling device 21 is different from the amount of flue gas entering the preheating device 19, there is coal gangue calcination and decomposition in the coal gangue suspension calcining furnace 22, or there is fuel combustion for heating to assist in the decomposition of coal gangue. The actual flue gas flow rate through the preheating device 19 is greater than the air flow rate through the cooling device 21. The wind speed at each key section in the cooling device 21 will be too low, making it difficult to meet the requirements of suspension material carrying. Therefore, based on the air volume required for the coal gangue calcination process of the system, the air inlets, inner cylinders, and connecting pipes of the remaining B-3 cyclone 8-3, B-4 cyclone 8-4, and B-5 cyclone 8-5 of the original B-series preheater 8 are modified to ensure that the cross-sectional wind speed of each air inlet, inner cylinder, and air outlet pipe of the three-stage cooling device 21-1, the two-stage cooling device 21-2, and the first-stage cooling device 21-3 of the hot-calcined coal gangue powder cooling device 21 is ≥15m / s, so as to ensure reasonable airflow carrying capacity and gas-solid separation efficiency.

[0047] To achieve better air-carrying effect, the secondary cooling device's feed pipe 21-2-1 is connected to the primary cooling device's air inlet pipe 21-3-1. Due to the inertia of the powder feeding, the connection point of the secondary cooling device's feed pipe 21-2-1 into the primary cooling device's air inlet pipe 21-3-1 needs to be at a certain height from the lower edge of the primary cooling device's air inlet pipe 21-3-1. The connection point should be at least 2 meters away from the lower edge (air interface) of the primary cooling device's air inlet pipe 21-3-1. The wind speed at the ordinary section of the primary cooling device's air inlet pipe 21-3-1 should be at least 15 m / s, and a narrowing structure should be adopted at its lower inlet, with a wind speed at the narrowed section at least 25 m / s. This higher wind speed ensures a better airflow sealing effect, guaranteeing that all the calcined coal gangue powder fed into the primary cooling device's air inlet pipe 21-3-1 is carried into the primary cooling device 21-3 by the air, preventing it from falling outside the primary cooling device's air inlet pipe 21-3-1.

[0048] The sixth aspect of the modification is as follows: Given the increased resistance of the system consisting of the preheating device 19, the coal gangue suspension calcining furnace 20, and the cooling device 21 connected in series after the modification, and the significant change in the flue gas volume discharged from the preheating device 19, the airflow and pressure head of the high-temperature fan are recalculated based on the exhaust gas parameters generated by the coal gangue suspension calcining system. The original high-temperature fan 23-1 of the cement clinker production line is replaced with the high-temperature fan 23-2 of the coal gangue suspension calcining production line. The flue gas in the coal gangue calcining system is then fed into the coal gangue grinding system by the modified high-temperature fan 23-2, ensuring that the modified high-temperature fan 23-2 operates at a higher efficiency point, thereby reducing the power consumption of the high-temperature fan 23-2.

[0049] The above-mentioned renovation and construction projects can be carried out in any order and can be completed simultaneously.

[0050] After the above modifications, the coal gangue suspension calcination production line includes a coal gangue stockpile 13, a coal gangue silo 14, a coal gangue grinding system 15, a coal gangue powder homogenization silo 16, a coal gangue powder weighing scale, a coal gangue powder feeding elevator 17, a coal gangue powder feeding chute 18, a preheating device 19, a gas-solid separation cyclone 20, a coal gangue suspension calcination furnace 22, a cooling device 21, and a high-temperature fan 23-2 for the coal gangue suspension calcination production line. Among them, the preheating device 19, the gas-solid separation cyclone 20, the coal gangue suspension calcination furnace 22, the cooling device 21, and the high-temperature fan 23-2 for the coal gangue suspension calcination production line constitute the coal gangue suspension calcination system.

[0051] The modified coal gangue suspension calcination production line has the following process: Air enters the coal gangue suspension calcination system through cooling device 21, and passes through cooling device 21, coal gangue suspension calcination furnace 22, gas-solid separation cyclone 20, and preheating device 19 in sequence, undergoing three processes: air heating, high-temperature flue gas formation, and high-temperature flue gas cooling. Finally, the flue gas is discharged from the flue gas outlet of preheating device 19 by the high-temperature fan 23-2 of the coal gangue suspension calcination production line. Low-temperature coal gangue powder enters the coal gangue suspension calcination system through preheating device 19, and passes through preheating device 19, coal gangue suspension calcination furnace 22, gas-solid separation cyclone 20, and cooling device 21 in sequence, undergoing three processes: coal gangue powder heating, suspension calcination activation, and cooling of the calcined coal gangue powder product. Finally, it is discharged from the discharge pipe 21-3-2 of the primary cooling device of cooling device 21.

[0052] Taking a 4000t / d five-stage double-series preheater cement clinker production line as an example, the flue gas volume at the outlet of the original decomposition furnace 9 is assumed to be 1.36 Nm3 / kg·cl, and the air volume entering the flue gas of each preheater is approximately 0.68 Nm3 / kg·cl. Using 1000 kcal / kg coal gangue for suspension calcination, and controlling the outlet temperature of the suspension calcination furnace 22 at around 800℃, based on the industrial and elemental analysis of coal gangue, and through thermal calculations, the waste gas volume generated by the suspension calcination of 1000t / d coal gangue is approximately half that of a 4000t / d cement production line. If the 4000t / d five-stage double-series preheater production line... A cement clinker production line with a dual-series preheater was transformed into a 1000t / d coal gangue suspension calcination production line. One series of the dual-series preheaters was transformed into preheating device 19, with each stage of the cyclone separator basically matching the amount of flue gas generated by calcining coal gangue. However, the other preheater was transformed into a cooling device 21, but the air volume and specifications were somewhat mismatched, and each stage of the cooling cyclone separator appeared to be too large. In addition, the decomposition furnace of a 4000t / d cement clinker production line was transformed into a coal gangue suspension calcination furnace according to this invention, calcining 1000t / d of coal gangue powder. The air velocity in the suspension calcination furnace was about half that of the decomposition furnace, which was too low. Therefore, the coal gangue calcination capacity can be increased to 1300t / d. The wind speed of the coal gangue suspension calcination furnace is relatively reasonable, meeting the requirements of both carrying and suspension calcination. However, the amount of flue gas generated from calcining coal gangue is slightly larger than that of the preheating device 19. The wind speed in the preheating device 19 is higher than that when producing cement clinker, but it is still within the normal design range of the cyclone separator. Thus, the wind speed through the suspension calcination furnace and the wind speed of the gas-solid separation cyclone separator are both within a reasonable range.

[0053] If calcining 1300t / d of coal gangue, the wind speed of the cooling device 21 in the suspension calcination system is lower than when it is used as a preheater for producing cement clinker. By modifying the inlet and outlet and connecting pipes of the three-stage cooling device 21-1, the two-stage cooling device 21-2, and the first-stage cooling device 21-3, and appropriately reducing their ventilation cross-sectional area, the cooling device 21 can be matched with the amount of air passing through it, and a reasonable wind speed range can be achieved.

[0054] Since the amount of coal gangue calcined is much lower than the amount of clinker produced, there is a certain margin in the equipment for coal gangue storage, grinding, conveying, metering, homogenization storage, and feeding, which can be used directly at low load. For the coal gangue grinding system 15, since the grinding equipment and classifying equipment have certain wind speed requirements, the output and operating air volume cannot be reduced too much. It is necessary to appropriately increase the output for operation and appropriately reduce the running time to balance the material with the suspension calcination system.

[0055] Even for cement clinker production lines of the same specifications, the amount of waste gas and cooling air generated by the suspension calcination of coal gangue will vary due to the different properties of the coal gangue. When the five-stage double-series preheater of the cement clinker production line is modified into a preheating and cooling device, the corresponding coal gangue processing capacity will be different, and the extent of the modification and the specifications and dimensions after the modification will be different. However, as long as it is modified to meet the reasonable operating parameters of suspension preheating, suspension calcination and suspension cooling, the cement clinker production line can be transformed into a coal gangue suspension calcination production line.

[0056] In the description herein, it should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0057] Finally, it should be noted that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for converting a cement clinker production line into a coal gangue suspension calcination production line, characterized in that, The cement clinker production line includes a five-stage double-series preheater and a decomposition furnace (9). The five-stage double-series preheater is divided into an A-series preheater (7) and a B-series preheater (8). The A-series preheater (7) is modified into a preheating device (19) for a coal gangue powder suspension calcination production line. The B-series preheater (8) is modified into a gas-solid separation cyclone (20) and a cooling device (21) for a coal gangue powder suspension calcination production line. A pipe furnace (22-2) is set between the air outlet of the decomposition furnace (9) and the air inlet of the gas-solid separation cyclone (20). The decomposition furnace (9) and the pipe furnace (22-2) are jointly modified into a coal gangue suspension calcination furnace (22).

2. The method for converting a cement clinker production line into a coal gangue suspension calcination production line according to claim 1, characterized in that, The A-column preheater (7) includes A-1 cyclone separator (7-1), A-2 cyclone separator (7-2), A-3 cyclone separator (7-3), A-4 cyclone separator (7-4), and A-5 cyclone separator (7-5). The B-column preheater (8) includes B-1 cyclone separator (8-1), B-2 cyclone separator (8-2), B-3 cyclone separator (8-3), B-4 cyclone separator (8-4), and B-5 cyclone separator (8-5). Remove the A-5 cyclone separator (7-5) of the A-column preheater, the B-1 cyclone separator (8-1) of the B-column preheater, and the corresponding air outlet pipes. Then, connect the A-1 cyclone separator (7-1), A-2 cyclone separator (7-2), A-3 cyclone separator (7-3), and A-5 cyclone separator (8-5). The four cyclone separators (7-4) are connected in series to form the preheating device (19), which are respectively set as a first-stage preheating device (19-1), a second-stage preheating device (19-2), a third-stage preheating device (19-3), and a fourth-stage preheating device (19-4). The B-2 cyclone separator (8-2) of the B-row preheater (8) is modified into the gas-solid separation cyclone separator (20). The B-3 cyclone separator (8-3), B-4 cyclone separator (8-4), and B-5 cyclone separator (8-5) of the B-row preheater (8) are connected in series to form the cooling device (21), which are respectively set as a third-stage cooling device (21-1), a second-stage cooling device (21-2), and a first-stage cooling device (21-3).

3. The method for converting a cement clinker production line into a coal gangue suspension calcination production line according to claim 2, characterized in that, The cement clinker production line also includes a smoke chamber (10), a rotary kiln (11), a cooler (12), and a tertiary air duct (9-1). The lower cone part (9-2) of the decomposition furnace (9) is disconnected from the smoke chamber (10), the tertiary air duct (9-1) is disconnected from the decomposition furnace, the tertiary air duct (9-1), the smoke chamber (10), the rotary kiln (11), and the cooler (12) are discarded, the lower cone part (9-2) of the decomposition furnace is transformed into the lower cone part (22-1) of the coal gangue suspension calcining furnace (22), and the air outlet (21-1-1) of the three-stage cooling device is connected to the lower cone part (22-1) of the calcining furnace through a pipeline.

4. The method for converting a cement clinker production line into a coal gangue suspension calcination production line according to claim 3, characterized in that, An air heater (25) is installed on the pipe between the air outlet (21-1-1) of the three-stage cooling device and the lower cone (22-1) of the calcining furnace.

5. The method for converting a cement clinker production line into a coal gangue suspension calcination production line according to claim 3, characterized in that, Connect the air outlet of the gas-solid separation cyclone (20) and the air inlet of the fourth-stage preheating device (19-4) through a pipe; disconnect the B-4 cyclone discharge pipe (8-4-1) from the decomposition furnace (9) and modify it into a secondary cooling device discharge pipe (21-2-1); set a downward air inlet pipe at the air inlet of the B-5 cyclone (8-5) and use it as a primary cooling device air inlet pipe (21-3-1), which is connected to the atmosphere; connect the secondary cooling device discharge pipe (21-2-1) with the primary cooling device air inlet pipe (21-3-1), and the interface of the two is ≥2m higher than the lower edge of the air inlet of the primary cooling device air inlet pipe (21-3-1); disconnect the B-5 cyclone discharge pipe (8-5-1) from the smoke chamber (10) and use it as a primary cooling device discharge pipe (21-3-2) of the primary cooling device (21-3).

6. The method for converting a cement clinker production line into a coal gangue suspension calcination production line according to claim 5, characterized in that, The lower cone section (22-1) of the calcining furnace has a constricted pipe structure with a constricted section wind speed of 25-35 m / s. The cross-sectional wind speed of each air inlet, inner cylinder and air outlet of the three-stage cooling device (21-1), the two-stage cooling device (21-2) and the first-stage cooling device (21-3) of the cooling device (21) is ≥15 m / s. The lower edge of the air inlet of the first-stage cooling device air inlet pipe (21-3-1) adopts a constricted structure with a constricted section wind speed of ≥25 m / s.

7. The method for converting a cement clinker production line into a coal gangue suspension calcination production line according to claim 1, characterized in that, The cement clinker production line also includes a limestone stockpile (1), a limestone silo (2), a raw meal grinding system (3), a raw meal homogenization silo (4), a raw meal weighing scale, a raw meal feeding elevator (5), and a first raw meal feeding chute (6-1), which are correspondingly modified into a coal gangue stockpile (13), a coal gangue silo (14), a coal gangue grinding system (15), a coal gangue powder homogenization silo (16), a coal gangue powder weighing scale, a coal gangue powder feeding elevator (17), and a coal gangue powder feeding chute (18). The bottom of (16) is set as a large-angle stacking structure. The coal gangue powder feeding elevator (17) is equipped with a hopper cleaning device. The drying heat source of the coal gangue grinding system (15) adopts the outlet flue gas of the preheating device (19). The cement clinker production line also includes a second raw material feeding chute (6-2), and the second raw material feeding chute (6-2) is removed. The cement clinker production line also includes a high-temperature fan (23-1) of the cement clinker production line, which is replaced with a high-temperature fan (23-2) of the coal gangue suspension calcination production line.

8. The method for converting a cement clinker production line into a coal gangue suspension calcination production line according to claim 7, characterized in that, The coal gangue stockpile (13) is equipped with a spraying device (13-1) and an infrared temperature measuring device (13-2). The spraying device (13-1) includes a spray gun (13-1-4) and a water spraying control system (13-1-6). Multiple spray guns (13-1-4) are set up and the spraying range fully covers the coal gangue stockpile. An infrared temperature measuring device (13-2) is set up within the spraying coverage area of ​​each spray gun (13-1-4). The spraying device (13-1) and the infrared temperature measuring device (13-2) are both monitored for temperature and automatically turned on and off by the water spraying control system (13-1-6).

9. The method for converting a cement clinker production line into a coal gangue suspension calcination production line according to claim 1, characterized in that, The coal gangue grinding system (15) and the coal gangue homogenization silo (16) are both equipped with explosion-proof bag dust collectors. The coal gangue grinding system (15) and the coal gangue homogenization silo (16) are both equipped with CO alarms and infrared temperature alarms, and are both associated with CO2 fire extinguishing devices (24). When the set CO concentration and temperature values ​​are exceeded, an alarm will be automatically triggered and the CO2 fire extinguishing device (24) will be activated.

10. The method for converting a cement clinker production line into a coal gangue suspension calcination production line according to claim 1, characterized in that, The process of the coal gangue suspension calcination production line is as follows: Air enters the production line through the cooling device (21), passes through the cooling device (21), the coal gangue suspension calcination furnace (22), the gas-solid separation cyclone (20), and the preheating device (19) in sequence, and undergoes three processes in sequence: air heating, high-temperature flue gas formation, and high-temperature flue gas cooling. Finally, the flue gas is drawn out from the flue gas outlet of the preheating device (19) by the high-temperature fan (23-2) of the coal gangue suspension calcination production line. Discharge; Low-temperature coal gangue powder enters the coal gangue suspension calcination system from the preheating device (19), and passes through the preheating device (19), coal gangue suspension calcination furnace (22), gas-solid separation cyclone (20), and cooling device (21) in sequence, undergoing three process processes: coal gangue powder heating, suspension calcination activation, and calcined coal gangue powder finished product cooling. Finally, the calcined and activated coal gangue powder finished product is discharged from the first-stage cooling device discharge pipe (21-3-2) of the cooling device (21).

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