Equipment utilizing kiln tail waste heat of cement kiln as well as use method and transformation method
By designing equipment for high-temperature and low-temperature raw material preheating systems and using kiln tail heat to heat raw material, the problem of failure to efficiently utilize kiln tail heat in the existing technology has been solved, and the flexible utilization and coal saving effect of cement enterprises has been achieved.
Patent Information
- Application Number
- CN202310942372.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2023-07-30
- Publication Date
- 2025-02-14
AI Technical Summary
The existing cement production process cannot flexibly choose to use the waste heat of the kiln tail flue gas to generate power or save coal according to coal prices, electricity prices and production needs, resulting in the failure of efficient use of the waste heat of the kiln tail.
A device including high-temperature and low-temperature raw material preheating system is designed. The auxiliary heat exchange device is installed at the flue gas outlet of the raw material preheating device, and the raw material is heated by kiln tail heat, and then the waste heat is flexibly selected to use waste heat for power generation or Dry raw materials.
It has achieved that cement enterprises flexibly choose to utilize the waste heat of kiln tail flue gas to reduce coal consumption, reduce production costs, and improve corporate competitiveness based on market coal prices and electricity prices.
Smart Images
Figure CN119436870A_ABST
Abstract
Description
Technical Field
[0001] The embodiments of the present disclosure relate to the technical field of cement clinker burning, and in particular to a device for utilizing waste heat from a cement kiln tail and a method for using the device, as well as a method for modifying the device for utilizing waste heat from a cement kiln tail. Background Art
[0002] In the existing cement production, waste heat from the kiln tail is used to generate electricity. Since the waste heat power generation technology emerged against the background of low coal prices and high electricity prices, and due to the differences in actual production needs of enterprises, the waste heat from the kiln tail flue gas has not been efficiently utilized, which is mainly reflected in the following points:
[0003] 1) Currently, waste heat from flue gas is used for power generation. When coal prices are low and electricity prices are high, enterprises can make profits. When coal prices are high and electricity prices are low, it will be more valuable for enterprises if they can use this part of waste heat from flue gas to save coal.
[0004] 2) The flue gas temperature out of the waste heat boiler is generally about 210°C, while the inlet temperature of the raw mill (i.e. the flue gas temperature requirement for raw material drying) is generally 150-180°C. In other words, from the perspective of raw material drying, the flue gas temperature of the waste heat boiler can be further reduced.
[0005] 3) Generally, the raw mill is shut down for about 4 hours a day. When the raw mill is shut down, the flue gas from the waste heat boiler will be cooled by spraying water in the humidification tower and then directly enter the dust collector at the end of the kiln, and then be discharged after dust collection. In this way, the heat of the flue gas is wasted.
[0006] 4) Changes in raw materials themselves. Since the raw materials used by enterprises are changing, for example, when there is sufficient rain in summer, the moisture content of the raw materials is high, and a higher flue gas temperature entering the mill is required for drying; when there is less rain in winter, the moisture content of the raw materials is low, and a lower flue gas temperature entering the mill can meet the drying requirements of the raw materials, and there is room for lowering the flue gas temperature leaving the waste heat boiler.
[0007] The existing production process does not support the flexible selection of flue gas waste heat power generation or raw material drying. The existing cement production process after the preheater is as follows: Figure 1 As shown, the dotted line is the flue gas flow direction; the solid line is the material flow direction. It can be seen that the flue gas at about 320°C exiting the preheater usually enters the waste heat boiler, using part of the waste heat of the flue gas to generate electricity. After heat exchange, the flue gas temperature is generally reduced to 210°C; when the waste heat boiler fails, the flue gas exiting the preheater can also directly enter the fan through the bypass pipe, and then pass through the humidification tower to reduce the temperature.
[0008] When the raw mill is running, the flue gas at the outlet of the waste heat boiler passes through the fan, and then enters the humidification tower (usually no water is sprayed when the raw mill is running), and then enters the raw mill. When part of the flue gas out of the mill is circulated back to the inlet of the raw mill, the inlet temperature of the raw mill is about 180°C; the raw materials in the raw mill are ground, sorted and dried, and the flue gas temperature of the raw mill is about 90-95°C; the flue gas out of the mill is dusted by the dust collector and discharged through the tail exhaust fan and the chimney at the end of the kiln.
[0009] When the raw mill is not running, the flue gas at the outlet of the waste heat boiler at about 210℃ passes through the fan and enters the humidification tower. When some water is sprayed in the humidification tower, the flue gas temperature is reduced to about 150℃; then it directly enters the dust collector at the end of the kiln and is discharged through the tail exhaust fan and the chimney at the end of the kiln.
[0010] Limited by existing production methods and system layout, the waste heat from the kiln tail gas generated by clinker calcination can only be used for power generation. Enterprises cannot flexibly choose to use waste heat from flue gas for power generation or coal saving according to the fluctuations in coal and electricity prices. Especially when the coal price cost is high and the electricity price cost is low, if the waste heat from flue gas can be used to save coal, it will be beneficial to reduce the production cost of enterprises and improve their competitiveness.
[0011] In addition, the existing waste heat utilization process at the kiln tail is limited by the constant area of the waste heat boiler and the inability to change the outlet flue gas position, resulting in the flue gas temperature at the waste heat boiler being basically constant at 210°C. When the raw mill is shut down or the moisture content of the raw material is low, the flue gas temperature can be further reduced. However, the existing process does not support the efficient and flexible utilization of the waste heat of the kiln tail flue gas.
[0012] For the above reasons, enterprises are in urgent need of a method and system that can efficiently and flexibly utilize waste heat from cement kiln tail. It allows enterprises to choose to use waste heat from kiln tail flue gas to generate electricity or preheat raw materials based on local coal prices, electricity prices, and actual production conditions, such as raw material moisture content and raw mill start-up and shutdown status, thereby saving coal. Summary of the invention
[0013] The present invention is proposed to solve or alleviate at least one aspect of the problems in the prior art.
[0014] An embodiment of the present invention relates to a device for utilizing waste heat from a cement kiln, comprising:
[0015] Raw meal preheating device;
[0016] Fan;
[0017] Raw meal homogenization silo;
[0018] A post-fan device, which is in communication with an outlet of the fan, and the raw meal prepared by the post-fan device is suitable for being introduced into a raw meal homogenization silo; and
[0019] Auxiliary heat exchange device,
[0020] in:
[0021] The auxiliary heat exchange device is arranged in the flue gas path of the flue gas outlet of the raw meal preheating device between the flue gas outlet of the raw meal preheating device and the inlet of the fan, and the auxiliary heat exchange device is suitable for heating the raw meal from the raw meal homogenization bin based on the flue gas from the flue gas outlet of the raw meal preheating device, and the heated raw meal is suitable for being fed into the raw meal preheating device.
[0022] Optionally, the equipment further comprises a waste heat boiler, the smoke outlet of the raw meal preheating device is connected to the smoke inlet of the waste heat boiler via a main smoke channel, and the smoke outlet of the waste heat boiler is connected to the inlet of the fan via a first channel provided with a first valve.
[0023] Optionally, the auxiliary heat exchange device includes a first raw meal preheater, which includes at least one first auxiliary cyclone, wherein: the flue gas outlet of the waste heat boiler is also connected to the material inlet of the first raw meal preheater via a second channel provided with a second valve, and the flue gas outlet of the first raw meal preheater is connected to the inlet of the fan via a third channel provided with a third valve; the raw meal outlet of the raw meal homogenization storage is connected to the second channel between the material inlet of the first raw meal preheater and the second valve; the raw meal outlet of the first raw meal preheater is connected to the raw meal preheating device.
[0024] Optionally, the first raw meal preheater comprises a first auxiliary cyclone, and a smoke outlet of the first auxiliary cyclone is connected to an inlet of the fan via a third channel provided with a third valve.
[0025] Optionally, the main flue gas channel is provided with a main flue gas valve; the equipment also includes a second raw meal preheater, the second raw meal preheater includes at least one second auxiliary cyclone, the flue gas outlet of the raw meal preheating device is also connected with the material inlet of the second raw meal preheater via a fourth channel provided with a fourth valve, and the flue gas outlet of the second raw meal preheater is connected with the inlet of the fan via a fifth channel provided with a fifth valve; the raw meal outlet of the second raw meal preheater is connected with the raw meal preheating device; the raw meal outlet of the raw meal homogenization storage is connected with the second raw meal preheater.
[0026] Optionally, the raw meal outlet of the first raw meal preheater and the raw meal outlet of the second raw meal preheater are connected to the raw meal preheating device via a common pipeline.
[0027] Optionally, the second raw meal preheater comprises a first-stage second auxiliary cyclone, a second-stage second auxiliary cyclone and a third-stage second auxiliary cyclone; the raw meal from the raw meal outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the third-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the raw meal preheating device; the raw meal from the raw meal outlet of the first-stage second auxiliary cyclone is suitable for entering the material inlet of the second-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the third-stage second auxiliary cyclone; the flue gas from the flue gas outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the first-stage second auxiliary cyclone together with the raw meal from the raw meal outlet of the raw meal homogenizing storage; the flue gas outlet of the first-stage second auxiliary cyclone serves as the flue gas outlet of the second raw meal preheater.
[0028] Optionally, the raw material outlet of the raw material homogenization storage is connected to the main raw material pipeline, the main raw material pipeline is branched into a first raw material pipeline and a second raw material pipeline, the first raw material pipeline is connected to the inlet of the raw material elevator via a first raw material valve; the second raw material pipeline is branched into a first branch to the first raw material preheater and provided with a second raw material valve, and a second branch to the second raw material preheater and provided with a third raw material valve; the raw material outlet of the first raw material preheater and the raw material outlet of the second raw material preheater are connected to the inlet of the raw material elevator.
[0029] Optionally, the auxiliary heat exchange device includes a second raw meal preheater, which includes at least one second auxiliary cyclone; the flue gas outlet of the raw meal preheating device is communicated with the material inlet of the second raw meal preheater via a fourth channel provided with a fourth valve and is communicated with the flue gas inlet of the waste heat boiler via a main flue gas channel provided with a main flue gas valve; the raw meal outlet of the second raw meal preheater is communicated with the raw meal preheating device; the smoke gas outlet of the second raw meal preheater is communicated with the inlet of the fan via a fifth channel provided with a fifth valve; the raw meal outlet of the raw meal homogenization storage is communicated with the second raw meal preheater.
[0030] According to another aspect of an embodiment of the present invention, a method for using the above-mentioned device for utilizing waste heat from the tail of a cement kiln is proposed, comprising the steps of:
[0031] The auxiliary heat exchange device heats the raw meal from the raw meal homogenization bin based on the flue gas from the raw meal preheating device; and
[0032] The heated raw meal is fed into the raw meal preheating device.
[0033] Optionally, the equipment also includes a waste heat boiler, the flue gas outlet of the raw meal preheating device is connected to the flue gas inlet of the waste heat boiler via a main flue gas channel, the flue gas outlet of the waste heat boiler is connected to the inlet of the fan via a first channel provided with a first valve, and the method includes the steps of: when it is necessary to use the waste heat boiler to generate electricity, the outlet flue gas of the raw meal preheating device is connected to the flue gas inlet of the waste heat boiler via the main flue gas channel.
[0034] Optionally, the post-fan device includes a raw meal mill; the auxiliary heat exchange device includes the above-mentioned first raw meal preheater, and the method includes the steps of: when the moisture content of the raw material entering the raw meal mill is high and the raw meal mill is running, the flue gas outlet of the waste heat boiler is connected to the inlet of the fan via a first channel provided with a first valve; and when the moisture content of the raw material entering the raw meal mill is low and / or the raw meal mill is not running, the flue gas outlet of the waste heat boiler is connected to the material inlet of the first raw meal preheater via a second channel provided with a second valve, and the flue gas outlet of the first raw meal preheater is connected to the inlet of the fan via a third channel provided with a third valve; the raw meal from the raw meal outlet of the raw meal homogenization storage is passed into the first raw meal preheater; the raw meal from the raw meal outlet of the first raw meal preheater is passed into the raw meal preheating device.
[0035] Optionally, the auxiliary heat exchange device includes the above-mentioned second raw meal preheater, and the method includes the steps of: when there is no need to generate electricity through the waste heat boiler, making the flue gas outlet of the raw meal preheating device communicate with the material inlet of the second raw meal preheater via a fourth channel provided with a fourth valve, and making the flue gas outlet of the second raw meal preheater communicate with the inlet of the fan via a fifth channel provided with a fifth valve, so as to bypass the waste heat boiler in the flue gas path of the outlet flue gas of the raw meal preheating device; making the raw meal from the raw meal outlet of the raw meal homogenization storage pass into the second raw meal preheater; making the raw meal from the raw meal outlet of the second raw meal preheater pass into the raw meal preheating device.
[0036] According to another aspect of an embodiment of the present invention, a method for modifying equipment that utilizes waste heat from a cement kiln tail is provided, wherein: the equipment that utilizes waste heat from a cement kiln tail comprises: a raw meal preheating device; a fan; a waste heat boiler, wherein the flue gas outlet of the raw meal preheating device is connected to the flue gas inlet of the waste heat boiler via a flue gas main channel, and the flue gas outlet of the waste heat boiler is connected to the inlet of the fan via a first channel provided with a first valve; a raw meal homogenizing silo; a fan rear device, which is connected to the outlet of the fan, and the raw meal recovered through the fan rear device is suitable for being introduced into the raw meal homogenizing silo, and wherein the modification method comprises the steps of:
[0037] An auxiliary heat exchange device is provided, which is arranged in the flue gas path of the flue gas outlet of the raw meal preheating device between the flue gas outlet of the raw meal preheating device and the inlet of the fan, and the auxiliary heat exchange device is suitable for heating the raw meal from the raw meal homogenization bin based on the flue gas from the flue gas outlet of the raw meal preheating device, and the heated raw meal is suitable for being fed into the raw meal preheating device.
[0038] Optionally, the method further includes the steps of: communicating the flue gas outlet of the waste heat boiler with the inlet of the fan via a first channel provided with a first valve; communicating the flue gas outlet of the waste heat boiler with the material inlet of the first raw meal preheater via a second channel provided with a second valve, and communicating the flue gas outlet of the first raw meal preheater with the inlet of the fan via a third channel provided with a third valve; communicating the raw meal outlet of the raw meal homogenization bin with the first raw meal preheater; and communicating the raw meal outlet of the first raw meal preheater with the raw meal preheating device.
[0039] Optionally, the method further includes the steps of: making the flue gas outlet of the raw meal preheating device communicate with the material inlet of the second raw meal preheater via a fourth channel provided with a fourth valve, and making the flue gas outlet of the second raw meal preheater communicate with the inlet of the fan via a fifth channel provided with a fifth valve, so as to bypass the waste heat boiler in the flue gas path of the outlet flue gas of the raw meal preheating device; making the raw meal outlet of the raw meal homogenizing storage communicate with the second raw meal preheater; and making the raw meal outlet of the second raw meal preheater communicate with the raw meal preheating device.
[0040] Optionally, the second raw meal preheater comprises a first-stage second auxiliary cyclone, a second-stage second auxiliary cyclone and a third-stage second auxiliary cyclone; the raw meal from the raw meal outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the third-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the raw meal preheating device; the raw meal from the raw meal outlet of the first-stage second auxiliary cyclone is suitable for entering the material inlet of the second-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the third-stage second auxiliary cyclone; the flue gas from the flue gas outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the first-stage second auxiliary cyclone together with the raw meal from the raw meal outlet of the raw meal homogenizing storage; the flue gas outlet of the first-stage second auxiliary cyclone serves as the flue gas outlet of the second raw meal preheater.
[0041] Optionally, the method further includes the steps of: connecting the raw material outlet of the raw material homogenization storage to the main raw material pipeline, the main raw material pipeline is branched into a first raw material pipeline and a second raw material pipeline, the first raw material pipeline is connected to the inlet of the raw material elevator via a first raw material valve; connecting the second raw material pipeline to the first raw material preheater and provided with a second raw material valve, and connecting the second raw material preheater and provided with a third raw material valve; connecting the raw material outlet of the first raw material preheater and the raw material outlet of the second raw material preheater to the inlet of the raw material elevator.
[0042] An embodiment of the present invention further relates to a cement kiln system, comprising the above-mentioned device for utilizing the waste heat at the tail of the cement kiln. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] Figure 1 A schematic diagram of a known device for utilizing waste heat from the tail of a cement kiln;
[0044] Figure 2 It is a schematic diagram of a device for utilizing waste heat from a cement kiln according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION
[0045] The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as limiting the present invention.
[0046] In view of the fact that the existing clinker calcining methods cannot meet the needs of enterprises to flexibly select preheater flue gas for power generation or coal saving according to coal prices and electricity prices, and cannot further reduce the outlet temperature of the waste heat boiler according to actual production needs, the present invention proposes a device and method for efficiently and flexibly utilizing the waste heat from the tail of a cement kiln, which can meet the needs of cement enterprises to flexibly select the utilization of the waste heat from the tail of the kiln based on the fluctuations in coal prices and electricity prices, as well as the changes in raw material moisture and the start and stop of the raw meal mill during production, so as to help enterprises save production costs and reduce coal consumption.
[0047] The following takes the raw material mill as a vertical mill, with a 3-stage high-temperature raw material preheating system and a 1-stage low-temperature raw material preheating system as an example. Figure 2 , describe the technical solution of the present invention in detail.
[0048] like Figure 2 As shown, a device for utilizing waste heat from the tail of a cement kiln comprises:
[0049] Existing preheater system (due to space limitations, only two cyclones, C2 and C1, are shown. As can be understood, there may be more cyclones);
[0050] Waste heat boiler 100;
[0051] Fan 101;
[0052] Fan after the device, such as Figure 1 or Figure 2 As shown, it may include a humidifying tower 102, a raw material mill 103, a cyclone 104, a circulating fan 105, a dust collector 106, a tail exhaust fan 107, and a kiln tail chimney 108;
[0053] Belt conveyor 109;
[0054] Warehouse elevator 110;
[0055] A raw material homogenization tank 111; and
[0056] Raw material scale 112.
[0057] Figure 2 The equipment shown for utilizing the waste heat at the tail of the cement kiln also includes: an elevator 201, a chute 202, a high-temperature raw material preheating system feeding device 203, a high-temperature raw material preheating system outlet pipe 204, a chute 205, a low-temperature raw material preheating system feeding device 206, a hot raw material conveying device 207, a kiln elevator 208, and a kiln raw material chute 209; and includes: high-temperature raw material preheating systems HP1, HP2, HP3; and a low-temperature raw material preheating system LP1.
[0058] The operation of the above-mentioned equipment utilizing the waste heat from the tail of the cement kiln is described in detail below.
[0059] According to the cost of coal price and electricity price, when the cost of coal price is low and the cost of electricity price is high:
[0060] The flue gas from the preheater C1 (i.e., the flue gas from the preheater system, as shown by the dotted line) enters the kiln tail waste heat boiler 100 under the control of a valve; after heat exchange with the water in the kiln tail waste heat boiler 100, it is determined whether the flue gas directly enters (1) the fan 101 or (2) the low-temperature raw meal preheating system LP1 according to the moisture content of the raw materials and the start / stop status of the raw meal mill.
[0061] When the moisture content of the raw materials is high and the raw mill is running, the flue gas is controlled by a valve to enter the fan 101. The flue gas after the fan 101 passes through the humidification tower 102 and enters the raw mill 103; after the raw material is dried in the raw mill 103, it enters the cyclone 104; the flue gas leaving the cyclone 104 passes through the circulating fan 105 and enters the dust collector 106, and is discharged from the kiln tail chimney 108 under the action of the tail exhaust fan 107. The finished raw meal collected by the cyclone 104 and the dust collector 106 is fed into the storage elevator 110 through the belt conveyor 109 and enters the raw meal homogenization storage 111; after being homogenized in the raw meal homogenization storage 111, it is fed into the raw meal scale 112 at the bottom of the storage, and after being weighed by the raw meal scale 112, it is fed into the kiln elevator 208, and through the kiln raw meal chute 209, it is fed into the heat exchange pipe of the existing preheater C2-C1, and then enters the existing kiln tail preheater system.
[0062] When the moisture content of the raw material is low and / or the raw mill is not running, the flue gas is controlled by a valve to enter the low-temperature raw meal preheating system LP1, and the flue gas out of LP1 enters the fan 101, and the subsequent process of the flue gas is the same as above.
[0063] Regarding the raw material flow, after being measured by the raw material scale 112, it is fed into the raw material preheating system elevator 201, and through the chute 205, it is fed into the low-temperature raw material preheating system feeding device 206, that is, the connecting pipeline from the waste heat boiler 100 to the low-temperature raw material waste heat system LP1. After heat exchange, the raw material collected by LP1 is fed into the kiln elevator 208 through the hot raw material conveying device 207, and through the kiln raw material chute 209, it is fed into the heat exchange pipeline of the existing preheater C2-C1 and enters the existing kiln tail preheater system.
[0064] When the coal price is high and the electricity price is low (bypassing the waste heat boiler and not generating electricity):
[0065] The flue gas of the preheater C1 (i.e., the flue gas of the preheater system, as shown by the dotted line) enters the high-temperature raw meal preheating system under the control of the valve; specifically, it enters the inlet of the lowest-level cyclone HP3, and after passing through HP3→HP2→HP1, the flue gas enters the outlet pipe 204 of the high-temperature raw meal preheating system; then, under the control of the valve, the flue gas after heat exchange is introduced into the fan 101, and the flue gas from the fan 101 then enters the humidification tower 102 and the raw meal mill 103; after drying the moisture of the raw materials in the raw meal mill 103, the flue gas enters the cyclone 104, the circulating fan 105, and the dust collector 106 respectively, and is discharged from the kiln tail chimney 108 under the action of the kiln tail exhaust fan 107.
[0066] The finished raw meal collected by the cyclone 104 and the dust collector 106 is fed into the storage elevator 110 through the belt conveyor 109 and enters the raw meal homogenization storehouse 111; after being homogenized in the raw meal homogenization storehouse 111, it is fed into the raw meal scale 112 at the bottom of the storehouse, and after being weighed by the raw meal scale 112, it is fed into the elevator 201, and through the chute 202, it is fed into the high-temperature raw meal preheating system feeding device 203, that is, the heat exchange pipe of HP2-HP1, and enters HP1 driven by the upward flue gas. After separation by HP1, the raw meal enters HP2, and after separation by HP2, the raw meal enters HP3; after separation by HP3, the raw meal is fed into the kiln elevator 208 through the hot raw meal conveying device 207, and is fed into the heat exchange pipe of the existing preheater C2-C1 through the kiln raw meal chute 209, and enters the existing kiln tail preheater system.
[0067] The present invention proposes a method for efficiently and flexibly utilizing waste heat from the tail of a cement kiln, specifically: adding a high-temperature raw meal preheating system and a low-temperature raw meal preheating system. It should be noted that in other embodiments of the present invention, although not shown, both the high-temperature raw meal preheating system and the low-temperature raw meal preheating system can be added, or only one of them can be added.
[0068] The high-temperature raw meal preheating system is connected in parallel with the existing waste heat boiler. When the coal price is low, the flue gas enters the waste heat boiler in accordance with the existing production process. When the coal price is high, the flue gas exiting the preheater enters the high-temperature raw meal preheating system to preheat the raw meal entering the kiln, thereby reducing the flue gas temperature and heat loss. The coal consumption per ton of clinker is expected to be reduced by 6-8kg standard coal / ton of clinker.
[0069] The low-temperature raw meal preheating system is connected in series with the existing waste heat boiler. When the flue gas enters the existing waste heat boiler, when the raw meal mill is shut down, or the moisture content of the raw material is low and a low drying temperature is required, the flue gas from the waste heat boiler enters the low-temperature raw meal preheating system, thereby increasing the temperature of the raw meal entering the kiln. If a level 1 low-temperature raw meal preheating system is used, it is expected that the temperature of the raw meal entering the kiln can be increased from 60°C to 150°C, the standard coal consumption per ton of clinker will be reduced by about 1kgce / tcl, and the waste heat power generation will be increased by about 5kWh / tcl.
[0070] The present invention proposes a device for efficiently and flexibly utilizing waste heat from the tail of a cement kiln, specifically:
[0071] The equipment includes a waste heat boiler at the kiln tail, a high-temperature raw meal preheating system connected in parallel with the waste heat boiler, a low-temperature raw meal waste heat system connected in series with the waste heat boiler, a valve for controlling the direction of flue gas flow, an elevator for entering the kiln, an elevator for entering the high-temperature raw meal preheating system, an elevator for entering the low-temperature raw meal preheating system, a valve for controlling the direction of raw meal flow, etc.
[0072] Among them, the high temperature raw material preheating system includes multiple stages ( Figure 2 The high-temperature raw meal preheating system includes a cyclone separator, a heat exchange pipe connected to the cyclone separator, a feeding device, etc. The feeding device is used to feed the raw meal that has been metered out of the homogenization bin into the high-temperature raw meal preheating system. The flue gas inlet of the high-temperature raw meal preheating system is connected to the outlet pipe of the existing preheater, and a valve is set on the connecting pipe; the outlet is connected to the inlet of the existing fan, and a valve is set on the connecting pipe. The elevator of the high-temperature raw meal preheating system is used to feed the raw meal that has been metered out of the homogenization bin into the feeding device.
[0073] The low temperature raw meal preheating system includes multiple stages ( Figure 2The low-temperature raw meal preheating system includes a cyclone separator, a heat exchange pipe connected to the cyclone separator, a feeding device, etc. The feeding device is used to feed the raw meal that has been metered out of the homogenization bin into the low-temperature raw meal preheating system. The flue gas inlet of the low-temperature raw meal preheating system is connected to the outlet pipe of the existing waste heat boiler, and a valve is provided on the connecting pipe; the outlet is connected to the inlet of the existing fan, and a valve is provided on the connecting pipe. The elevator of the low-temperature raw meal preheating system is used to feed the raw meal that has been metered out of the homogenization bin into the feeding device of the low-temperature raw meal preheating system.
[0074] Both high-temperature and low-temperature raw material preheating systems are equipped with hot raw material conveying devices to convey hot raw materials after heat exchange; the kiln elevator is resistant to high temperatures and is used to feed the raw materials that have been metered out of the homogenization bin or the hot raw materials that have been heat exchanged into the existing preheater system. The valve that controls the flow direction of the raw materials determines whether the metered raw materials are fed into the kiln elevator or the high-temperature or low-temperature raw material preheating system elevator.
[0075] In the equipment for utilizing waste heat at the tail of cement kiln of the present invention, waste heat boiler may not be provided. In this case, in the case of providing auxiliary heat exchange devices such as the high-temperature raw material preheating system and / or the low-temperature raw material preheating system described above, waste heat at the tail of kiln can still be effectively utilized. In the case of not providing waste heat boiler, only high-temperature raw material preheating system or low-temperature raw material preheating system may be provided.
[0076] It should be pointed out that in the embodiments of the present invention, high temperature and low temperature are relative. The high temperature in the so-called "high-temperature raw meal preheating system" means that the temperature of the flue gas entering the raw meal preheating system is higher than the temperature of the flue gas entering the so-called "low-temperature raw meal preheating system". In other words, high temperature and low temperature do not refer to a specific temperature range. It is just that when two raw meal preheating systems are compared together, the temperature of the flue gas entering different raw meal preheating systems is different.
[0077] In the present invention, an auxiliary heat exchange device is proposed. Figure 2 The auxiliary heat exchange device is arranged between the smoke outlet of the raw meal preheating device and the inlet of the fan in the smoke path of the smoke outlet of the existing raw meal preheating device (C1 and C2), and the auxiliary heat exchange device is suitable for heating the raw meal from the raw meal homogenizing silo based on the smoke from the smoke outlet of the raw meal preheating device, and the heated raw meal is suitable for being fed into the raw meal preheating device.
[0078] As can be understood, the technical solution of the present invention can be applied to cement kiln systems. The equipment for utilizing the waste heat at the tail of a cement kiln of the present invention can also be used to transform the waste heat utilization equipment at the tail of an existing cement kiln.
[0079] Based on the above, the present invention proposes a device for utilizing the waste heat at the tail of a cement kiln, comprising:
[0080] Raw meal preheating device;
[0081] Fan;
[0082] Raw meal homogenization silo;
[0083] A post-fan device is communicated with an outlet of the fan, and the raw meal recovered through the post-fan device is suitable for being introduced into a raw meal homogenization silo; and
[0084] Auxiliary heat exchange device,
[0085] in:
[0086] The auxiliary heat exchange device is arranged in the flue gas path of the flue gas outlet of the raw meal preheating device between the flue gas outlet of the raw meal preheating device and the inlet of the fan, and the auxiliary heat exchange device is suitable for heating the raw meal from the raw meal homogenization bin based on the flue gas from the flue gas outlet of the raw meal preheating device, and the heated raw meal is suitable for being fed into the raw meal preheating device.
[0087] Optionally, the equipment further comprises a waste heat boiler, the flue gas outlet of the raw meal preheating device is connected to the flue gas inlet of the waste heat boiler via a main flue gas channel, and the flue gas outlet of the waste heat boiler is connected to the inlet of the fan via a first channel provided with a first valve.
[0088] Optionally, the auxiliary heat exchange device includes a first raw meal preheater, which includes at least one first auxiliary cyclone, wherein: the flue gas outlet of the waste heat boiler is also connected to the material inlet of the first raw meal preheater via a second channel provided with a second valve, and the flue gas outlet of the first raw meal preheater is connected to the inlet of the fan via a third channel provided with a third valve; the raw meal outlet of the raw meal homogenization storage is connected to the second channel between the material inlet of the first raw meal preheater and the second valve; the raw meal outlet of the first raw meal preheater is connected to the raw meal preheating device.
[0089] Alternatively, the auxiliary heat exchange device includes a second raw meal preheater, which includes at least one second auxiliary cyclone; the flue gas outlet of the raw meal preheating device is communicated with the material inlet of the second raw meal preheater via a fourth channel provided with a fourth valve and is communicated with the flue gas inlet of the waste heat boiler via a main flue gas channel provided with a main flue gas valve; the raw meal outlet of the second raw meal preheater is communicated with the raw meal preheating device; the flue gas outlet of the second raw meal preheater is communicated with the inlet of the fan via a fifth channel provided with a fifth valve; the raw meal outlet of the raw meal homogenization storage is communicated with the second raw meal preheater.
[0090] The present invention also proposes a method for using the above-mentioned equipment for utilizing the waste heat at the tail of a cement kiln, comprising the steps of:
[0091] The auxiliary heat exchange device heats the raw meal from the raw meal homogenization bin based on the flue gas from the raw meal preheating device; and
[0092] The heated raw meal is fed into the raw meal preheating device.
[0093] The present invention also proposes a method for transforming equipment that utilizes waste heat from the tail of a cement kiln, wherein:
[0094] The equipment for utilizing the waste heat at the tail of a cement kiln comprises:
[0095] Raw meal preheating device;
[0096] Fan;
[0097] A waste heat boiler, a flue gas outlet of the raw meal preheating device is connected to a flue gas inlet of the waste heat boiler via a flue gas main channel, and a flue gas outlet of the waste heat boiler is connected to an inlet of the fan via a first channel provided with a first valve;
[0098] Raw meal homogenization silo;
[0099] The fan post-device is connected to the fan outlet, and the raw meal recovered through the fan post-device is suitable for entering the raw meal homogenization silo.
[0100] And wherein, the transformation method comprises the steps of:
[0101] An auxiliary heat exchange device is provided, which is arranged in the flue gas path of the flue gas outlet of the raw meal preheating device between the flue gas outlet of the raw meal preheating device and the inlet of the fan, and the auxiliary heat exchange device is suitable for heating the raw meal from the raw meal homogenization bin based on the flue gas from the flue gas outlet of the raw meal preheating device, and the heated raw meal is suitable for being fed into the raw meal preheating device.
[0102] Based on the technical solution of the present invention, the present invention can achieve at least one of the following technical effects:
[0103] a. The present invention proposes a method and device for efficiently and flexibly utilizing waste heat from the tail of a cement kiln. By adding a high-temperature raw meal preheating system and other devices connected in parallel with the waste heat boiler at the tail of the kiln, cement enterprises can flexibly choose to utilize the waste heat of flue gas from the preheater to generate electricity or dry raw meal according to the fluctuations of coal and electricity prices in the market, thereby saving coal, reducing production costs and improving corporate competitiveness.
[0104] b. When choosing to use the waste heat from the kiln exhaust gas to dry the raw material, use Figure 2 The example shown is a three-stage high-temperature raw meal preheating system. Preliminary calculations show that the preheater flue gas temperature can be reduced from the current 300°C to 180°C, and the coal consumption per ton of clinker can be reduced by 6-8kg standard coal / ton of clinker. In this way, while ensuring the heat required for raw material drying, the system thermal efficiency is increased and the burning energy consumption is reduced.
[0105] c. The present invention proposes a method and device for efficiently and flexibly utilizing waste heat from cement kiln tail. By adding a low-temperature raw meal preheating system in series with the waste heat boiler at the kiln tail, cement enterprises can flexibly choose whether to use the flue gas from the waste heat boiler at the kiln tail to directly enter the humidification tower / raw meal mill or the low-temperature raw meal preheating system according to the start-stop status of the raw meal mill and the moisture content of the raw materials. In this way, the heat of the flue gas can be fully utilized while ensuring the drying effect of the raw meal, thereby reducing the production cost of the enterprise and improving the competitiveness of the enterprise.
[0106] d. When the flue gas from the waste heat boiler at the kiln tail is selected to further dry the raw material, the following Figure 2 The example shown is a low-temperature raw meal preheating system of level 1. Preliminary calculations show that the flue gas temperature of the waste heat boiler can be reduced from 210°C to about 150°C, the raw meal temperature entering the kiln can be increased from 60°C to about 150°C, and the outlet temperature of the preheater can be increased by about 40°C, the standard coal consumption per ton of clinker can be reduced by about 1kgce / tcl, and the waste heat power generation can be increased by about 5kWh / tcl.
[0107] e. The high temperature / low temperature raw meal preheating system can also help increase the contact area and time between the raw meal and the flue gas, thereby improving the raw meal's ability to absorb SO2 in the flue gas and reducing the emission concentration of SO2 in the flue gas.
[0108] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made to the embodiments and combinations of elements may be made without departing from the principles and spirit of the invention, the scope of the invention being defined by the appended claims and their equivalents.
Claims
1. A device for utilizing waste heat from the tail of a cement kiln, comprising: Raw meal preheating device; Fan; Raw meal homogenization silo; A post-fan device, which is in communication with an outlet of the fan, and the raw meal prepared by the post-fan device is suitable for being introduced into a raw meal homogenization silo; and Auxiliary heat exchange device, in: The auxiliary heat exchange device is arranged in the flue gas path of the flue gas outlet of the raw meal preheating device between the flue gas outlet of the raw meal preheating device and the inlet of the fan, and the auxiliary heat exchange device is suitable for heating the raw meal from the raw meal homogenization bin based on the flue gas from the flue gas outlet of the raw meal preheating device, and the heated raw meal is suitable for being fed into the raw meal preheating device.
2. The device according to claim 1, further comprising: The flue gas outlet of the waste heat boiler and the raw material preheating device are connected to the flue gas inlet of the waste heat boiler via the main flue gas channel, and the flue gas outlet of the waste heat boiler is connected to the inlet of the fan via a first channel provided with a first valve.
3. The apparatus according to claim 2, wherein: The auxiliary heat exchange device comprises a first raw meal preheater, wherein the first raw meal preheater comprises at least one first auxiliary cyclone. in: The flue gas outlet of the waste heat boiler is also communicated with the material inlet of the first raw meal preheater via a second channel provided with a second valve, and the flue gas outlet of the first raw meal preheater is communicated with the inlet of the fan via a third channel provided with a third valve; The raw meal outlet of the raw meal homogenization bin is communicated with the second channel between the material inlet of the first raw meal preheater and the second valve; The raw meal outlet of the first raw meal preheater is communicated with the raw meal preheating device.
4. The apparatus according to claim 3, wherein: The first raw meal preheater comprises a first auxiliary cyclone, and a smoke outlet of the first auxiliary cyclone is communicated with an inlet of the fan via a third channel provided with a third valve.
5. The apparatus according to claim 3 or 4, wherein: The main smoke channel is provided with a main smoke valve; The equipment further comprises a second raw meal preheater, the second raw meal preheater comprises at least one second auxiliary cyclone, the smoke outlet of the raw meal preheater is further connected to the material inlet of the second raw meal preheater via a fourth channel provided with a fourth valve, and the smoke outlet of the second raw meal preheater is connected to the inlet of the fan via a fifth channel provided with a fifth valve; The raw meal outlet of the second raw meal preheater is communicated with the raw meal preheating device; The raw meal outlet of the raw meal homogenization bin is communicated with the second raw meal preheater.
6. The apparatus according to claim 5, wherein: The raw meal outlet of the first raw meal preheater and the raw meal outlet of the second raw meal preheater are communicated with the raw meal preheating device via a common pipeline.
7. The apparatus of claim 5, wherein: The second raw meal preheater comprises a first-stage second auxiliary cyclone, a second-stage second auxiliary cyclone and a third-stage second auxiliary cyclone; The raw meal from the raw meal outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the third-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the raw meal preheating device; The raw meal from the raw meal outlet of the first-stage second auxiliary cyclone is suitable for entering the material inlet of the second-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the third-stage second auxiliary cyclone; The flue gas from the flue gas outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the first-stage second auxiliary cyclone together with the raw meal from the raw meal outlet of the raw meal homogenization silo; The flue gas outlet of the first-stage second auxiliary cyclone serves as the flue gas outlet of the second raw meal preheater.
8. The apparatus of claim 5, wherein: The raw material outlet of the raw material homogenizing silo is connected to the main raw material pipeline, the main raw material pipeline is branched into a first raw material pipeline and a second raw material pipeline, and the first raw material pipeline is connected to the inlet of the raw material elevator via a first raw material valve; The second raw material pipeline branches into a first branch leading to the first raw material preheater and provided with a second raw material valve, and a second branch leading to the second raw material preheater and provided with a third raw material valve; The raw meal outlet of the first raw meal preheater and the raw meal outlet of the second raw meal preheater are communicated with the inlet of the raw meal elevator.
9. The apparatus of claim 2, wherein: The auxiliary heat exchange device comprises a second raw meal preheater, the second raw meal preheater comprises at least one second auxiliary cyclone, the flue gas outlet of the raw meal preheater is communicated with the material inlet of the second raw meal preheater via a fourth channel provided with a fourth valve, and is communicated with the flue gas inlet of the waste heat boiler via a main flue gas channel provided with a main flue gas valve; The raw meal outlet of the second raw meal preheater is communicated with the raw meal preheating device; The smoke outlet of the second raw meal preheater is communicated with the inlet of the fan via a fifth channel provided with a fifth valve; The raw meal outlet of the raw meal homogenization bin is communicated with the second raw meal preheater.
10. The apparatus of claim 9, wherein: The second raw meal preheater comprises a first-stage second auxiliary cyclone, a second-stage second auxiliary cyclone and a third-stage second auxiliary cyclone; The raw meal from the raw meal outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the third-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the raw meal preheating device; The raw meal from the raw meal outlet of the first-stage second auxiliary cyclone is suitable for entering the material inlet of the second-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the third-stage second auxiliary cyclone; The flue gas from the flue gas outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the first-stage second auxiliary cyclone together with the raw meal from the raw meal outlet of the raw meal homogenization silo; The flue gas outlet of the first-stage second auxiliary cyclone serves as the flue gas outlet of the second raw meal preheater.
11. A method for using the equipment for utilizing the waste heat of a cement kiln according to any one of claims 1 to 10, comprising the steps of: The auxiliary heat exchange device heats the raw meal from the raw meal homogenization bin based on the flue gas from the raw meal preheating device; and The heated raw meal is fed into the raw meal preheating device.
12. The method according to claim 11, wherein: The device is a device according to claim 2, and the method comprises the steps of: When it is necessary to utilize the waste heat boiler to generate electricity, the outlet flue gas of the raw meal preheating device is connected to the flue gas inlet of the waste heat boiler via the main flue gas channel.
13. The method according to claim 12, wherein: The post-fan device includes a raw mill; The device is a device according to claim 3, and the method comprises the steps of: When the moisture content of the raw material entering the raw mill is high and the raw mill is running, the flue gas outlet of the waste heat boiler is connected to the inlet of the fan via the first channel provided with the first valve; and When the moisture content of the raw material entering the raw meal mill is low and / or the raw meal mill is not running, the flue gas outlet of the waste heat boiler is communicated with the material inlet of the first raw meal preheater via a second channel provided with a second valve, and the flue gas outlet of the first raw meal preheater is communicated with the inlet of the fan via a third channel provided with a third valve; the raw meal from the raw meal outlet of the raw meal homogenizing storage is passed into the first raw meal preheater; the raw meal from the raw meal outlet of the first raw meal preheater is passed into the raw meal preheating device.
14. The method of claim 12, wherein: The device is a device according to claim 9, and the method comprises the steps of: In the case where there is no need to generate electricity through the waste heat boiler, the flue gas outlet of the raw meal preheating device is communicated with the material inlet of the second raw meal preheater via a fourth channel provided with a fourth valve, and the flue gas outlet of the second raw meal preheater is communicated with the inlet of the fan via a fifth channel provided with a fifth valve, so as to bypass the waste heat boiler in the flue gas path of the outlet flue gas of the raw meal preheating device; The raw meal from the raw meal outlet of the raw meal homogenization storage is passed into the second raw meal preheater; The raw meal from the raw meal outlet of the second raw meal preheater is passed into the raw meal preheating device.
15. A method for transforming equipment using waste heat from the tail of a cement kiln, wherein: The equipment for utilizing the waste heat at the tail of a cement kiln comprises: Raw meal preheating device; Fan; A waste heat boiler, a flue gas outlet of the raw meal preheating device is connected to a flue gas inlet of the waste heat boiler via a flue gas main channel, and a flue gas outlet of the waste heat boiler is connected to an inlet of the fan via a first channel provided with a first valve; Raw meal homogenization silo; The fan post-device is connected to the fan outlet, and the raw meal recovered through the fan post-device is suitable for entering the raw meal homogenization silo. And wherein, the transformation method comprises the steps of: An auxiliary heat exchange device is provided, which is arranged in the flue gas path of the flue gas outlet of the raw meal preheating device between the flue gas outlet of the raw meal preheating device and the inlet of the fan, and the auxiliary heat exchange device is suitable for heating the raw meal from the raw meal homogenization bin based on the flue gas from the flue gas outlet of the raw meal preheating device, and the heated raw meal is suitable for being fed into the raw meal preheating device.
16. The method according to claim 15, further comprising the steps of: The flue gas outlet of the waste heat boiler is connected to the inlet of the fan via a first channel provided with a first valve; and The flue gas outlet of the waste heat boiler is communicated with the material inlet of the first raw meal preheater via a second channel provided with a second valve, and the flue gas outlet of the first raw meal preheater is communicated with the inlet of the fan via a third channel provided with a third valve; the raw meal outlet of the raw meal homogenizing bin is communicated with the first raw meal preheater; the raw meal outlet of the first raw meal preheater is communicated with the raw meal preheating device.
17. The method according to claim 15 or 16, further comprising the steps of: The flue gas outlet of the raw meal preheating device is communicated with the material inlet of the second raw meal preheater via a fourth channel provided with a fourth valve, and the flue gas outlet of the second raw meal preheater is communicated with the inlet of the fan via a fifth channel provided with a fifth valve, so as to bypass the waste heat boiler in the flue gas path of the outlet flue gas of the raw meal preheating device; The raw meal outlet of the raw meal homogenization bin is connected to the second raw meal preheater; The raw meal outlet of the second raw meal preheater is connected to the raw meal preheating device.
18. The method of claim 17, wherein: The second raw meal preheater comprises a first-stage second auxiliary cyclone, a second-stage second auxiliary cyclone and a third-stage second auxiliary cyclone; The raw meal from the raw meal outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the third-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the raw meal preheating device; The raw meal from the raw meal outlet of the first-stage second auxiliary cyclone is suitable for entering the material inlet of the second-stage second auxiliary cyclone together with the flue gas from the flue gas outlet of the third-stage second auxiliary cyclone; The flue gas from the flue gas outlet of the second-stage second auxiliary cyclone is suitable for entering the material inlet of the first-stage second auxiliary cyclone together with the raw meal from the raw meal outlet of the raw meal homogenization silo; The flue gas outlet of the first-stage second auxiliary cyclone serves as the flue gas outlet of the second raw meal preheater.
19. The method according to claim 18, further comprising the steps of: The raw material outlet of the raw material homogenization bin is connected to the main raw material pipeline, the main raw material pipeline is branched into a first raw material pipeline and a second raw material pipeline, and the first raw material pipeline is connected to the inlet of the raw material elevator via a first raw material valve; The second raw material pipeline is branched into a first branch leading to the first raw material preheater and provided with a second raw material valve, and a second branch leading to the second raw material preheater and provided with a third raw material valve; The raw meal outlet of the first raw meal preheater and the raw meal outlet of the second raw meal preheater are connected to the inlet of the raw meal elevator.
20. A cement kiln system, comprising the device for utilizing waste heat from the tail of a cement kiln according to any one of claims 1 to 10.