Cement kiln multi-source heterogeneous fuel treatment device and use method thereof

Abstract

The invention discloses a use method of a cement kiln multi-source heterogeneous fuel treatment device, which comprises the following steps: step 1, adding alternative fuel into the cement kiln multi-source heterogeneous fuel treatment device, and screening the alternative fuel in the cement kiln multi-source heterogeneous fuel treatment device; secondly, the light and small-particle alternative fuel screened out in the first step enters a first area of a decomposing furnace, the heavy alternative fuel enters a pretreatment furnace, and the light and large-particle alternative fuel enters a second area of the decomposing furnace; step 3, in the step 2, the alternative fuel treated by the pretreatment furnace enters a third area of the decomposing furnace; wherein the first area, the second area and the third area of the decomposing furnace are sequentially arranged from top to bottom in the height direction of the decomposing furnace. By means of the using method, the quality of the alternative fuel in the same area in the decomposing furnace can be similar, synchronous combustion of the alternative fuel in the decomposing furnace can be achieved, and therefore the stability of a sintering system is guaranteed.

Description

Technical Field

[0001] The present invention relates to the field of alternative fuel use, and in particular to a cement kiln multi-source heterogeneous fuel processing device and a use method thereof. Background Art

[0002] In recent years, the cement industry has been facing severe pressure to reduce carbon emissions. In response to the pressure to reduce carbon emissions, the use of alternative fuels is seen as one of the key measures for cement kilns to achieve carbon reduction targets.

[0003] However, due to the poor classification and overall low quality of domestic alternative fuels, cement companies find it difficult to find alternative fuels with stable quality and suitable for their own cement kiln operating conditions when choosing alternative fuels. Compared with traditional coal fuels, current alternative fuels have obvious gaps in key indicators such as calorific value, combustion stability, and pollutant emissions. This leads to the fact that in actual application, it is difficult to achieve ideal combustion effects by directly putting these alternative fuels into the decomposition furnace of cement kilns, and it is impossible to give full play to the emission reduction advantages of alternative fuels.

[0004] At present, the cement industry mainly uses two methods to deal with alternative fuels: one is to directly put the alternative fuel into the decomposition furnace. This method cannot achieve effective homogenization of multi-source heterogeneous fuels. The combustion process of the fuel in the decomposition furnace is extremely unstable, which can easily cause large fluctuations in the operating conditions of the cement kiln, seriously affecting the continuity of cement production and product quality; the other is to pre-treat the alternative fuel in a single pre-combustion furnace outside the kiln before putting it into the decomposition furnace. Although this method has carried out preliminary treatment of the alternative fuel to a certain extent, due to the limitations of the pretreatment process, the homogenization effect on multi-source heterogeneous fuels is still very limited. There are still significant quality differences in the pretreated fuels, and most of the alternative fuels treated in the pre-combustion furnace are fed at a single point, which makes the dispersion effect of the fuel in the decomposition furnace extremely poor.

[0005] In summary, how to effectively achieve large-scale replacement of multi-source heterogeneous fuels while not reducing the fluctuations in cement kiln operating conditions has become a key technical problem that needs to be urgently solved in the cement industry. Summary of the invention

[0006] The purpose of the present invention is to provide a cement kiln multi-source heterogeneous fuel processing device and a method of using the same, the use of the method can make the quality of alternative fuels in the same area of the decomposition furnace converge, which is conducive to the synchronous combustion of alternative fuels in the decomposition furnace, thereby ensuring the stability of the firing system.

[0007] In order to achieve the above-mentioned object, the present invention provides a method for using a cement kiln multi-source heterogeneous fuel processing device, the method comprising:

[0008] Step 1: Add alternative fuel to the multi-source heterogeneous fuel treatment device of the cement kiln, and screen the alternative fuel in the multi-source heterogeneous fuel treatment device of the cement kiln;

[0009] Step 2: The light and small-particle alternative fuel screened in Step 1 enters the first zone of the decomposition furnace, the heavy alternative fuel enters the pretreatment furnace, and the light large-particle alternative fuel enters the second zone of the decomposition furnace;

[0010] Step 3: In Step 2, the alternative fuel treated by the pretreatment furnace enters the third zone of the decomposition furnace;

[0011] Among them, the first zone, the second zone, and the third zone of the decomposition furnace are arranged in sequence from top to bottom along the height direction of the decomposition furnace.

[0012] Preferably, in Step 1, the alternative fuel is subjected to primary separation through a screening pipeline. The alternative fuel enters the screening pipeline, and there is a gas moving upward from bottom to top in the screening pipeline. The heavy fuel obtained by primary separation enters the pretreatment furnace.

[0013] Preferably, the lighter alternative fuel obtained by primary separation enters a cyclone for secondary separation. The medium-quality alternative fuel collected at the dust collection port of the cyclone is sent to the pretreatment furnace, and the outlet of the cyclone is connected to the first zone of the decomposition furnace.

[0014] Preferably, a screen is provided at the connection position between the outlet of the cyclone and the first zone for tertiary separation of the alternative fuel. The smaller-particle alternative fuel enters the first zone of the decomposition furnace, and the larger-particle alternative fuel enters the second zone of the decomposition furnace through a feed chute.

[0015] Preferably, in Step 3, a reduced-diameter pipe is provided below the third zone, and the alternative fuel entering the third zone is subjected to quaternary separation through the reduced-diameter pipe.

[0016] The present invention also provides a multi-source heterogeneous fuel treatment device for a cement kiln. The multi-source heterogeneous fuel treatment device for a cement kiln is connected to a decomposition furnace and includes an alternative fuel inlet, a high-temperature air supply pipe, a screening pipeline connected to the high-temperature air supply pipe, a cyclone, a screen, a feed chute, and a pretreatment furnace. The screening pipeline is connected to the inlet of the cyclone, the dust collection port of the cyclone is connected to the high-temperature air supply pipe, the outlet of the cyclone is connected to the first zone, the screen is arranged at the connection between the cyclone (22) and the first zone (11), the high-temperature air supply pipe is connected to the pretreatment furnace, the feed chute is connected to the second zone, and the pretreatment furnace is connected to the third zone;

[0017] A gate is provided on the high-temperature air supply pipe, and the air flow rate in the screening pipeline can be controlled by controlling the gate.

[0018] Preferably, the air temperature in the high-temperature air supply pipe is 950 - 1150 °C.

[0019] Preferably, a three-way valve is provided on the blanking chute pipe, and the three-way valve controls the blanking chute pipe to be connected to the second zone of the decomposition furnace and the pretreatment furnace respectively.

[0020] Preferably, a raw meal feeding pipe for cooling the pretreatment furnace is provided in the pretreatment furnace, and a raw meal control valve is provided on the raw meal feeding pipe.

[0021] Preferably, the temperature in the pretreatment furnace is set to 800-1000 °C. A temperature sensor for detecting the temperature in the pretreatment furnace is provided in the pretreatment furnace, and the temperature sensor is electrically connected to the three-way valve and the raw meal control valve.

[0022] According to the above technical solution, the multi-source heterogeneous fuel treatment device of the cement kiln of the present invention can screen the alternative fuel. Through this screening effect, alternative fuels with light small particles, light large particles, and heavy alternative fuels can be obtained. The alternative fuel with light small particles is easy to burn and has a short combustion time. When it is sent to the top of the decomposition furnace, it can burn out quickly, effectively release its combustion calorific value, and will not cause waste of heat energy; the alternative fuel with light large particles is sent to the second zone in the middle of the decomposition furnace. In the second zone, the alternative fuel with light large particles burns while rising with the hot air. Since the position of the second zone is relatively low, the alternative fuel in the second zone can obtain more combustion time. As the alternative fuel with light large particles continues to burn, its particle size will continuously shrink. Therefore, during the continuous combustion and rising process of the alternative fuel with light large particles, its quality is also continuously increasing. Until the alternative fuel with light large particles rises to the first zone, its particle size has shrunk to the same as that of the alternative fuel with light small particles. Therefore, in this way, the alternative fuel in the first zone can be homogenized, which is beneficial to the stable operation of the decomposition furnace.

[0023] The heavy alternative fuel usually contains undried moisture. Therefore, the heavy fuel will first be sent into the pretreatment furnace. The pretreatment furnace will dry and pre-burn the heavy fuel to improve the quality of the alternative fuel and prevent the heavy fuel from entering the decomposition furnace and affecting the operation of the decomposition furnace. The heavy fuel treated by the pretreatment furnace is sent to the third zone at the bottom of the decomposition furnace. Considering the differences in the degree of drying and pre-combustion and the water content of the heavy fuel itself, a part of the fuel with slightly higher water content after drying of the heavy fuel will first settle into the reduced diameter pipe after entering the third zone. As the pipe diameter becomes smaller, the cross-sectional wind speed will increase. Therefore, this part of the fuel will be affected by a higher speed gas during the falling process and will finally change its movement direction and rise with the wind. During this process, these heavy fuels burn while moving in the decomposition furnace, and during the combustion process, the moisture in the heavy fuel will be further evaporated, and at the same time, the combustion will also reduce the particle size of the heavy fuel and improve the quality of the heavy fuel. Therefore, during the rising process of the heavy alternative fuel, it will successively enter the second zone and the first zone, and at the same time, with the continuous improvement of its quality, the quality of the fuels in different regions of the decomposition furnace will tend to be the same.

[0024] In summary, by screening alternative fuels and feeding alternative fuels of different qualities to different height positions in the decomposition furnace, the qualities of alternative fuels in the same area of the decomposition furnace can converge, which is beneficial to achieving the synchronous combustion of alternative fuels in the decomposition furnace, thereby ensuring the stability of the firing system. Moreover, through this control method, alternative fuels of different qualities can be completely burned in the decomposition furnace, achieving the purpose of maximizing the utilization of the calorific value of alternative fuels. Therefore, the use method of the multi-source heterogeneous fuel treatment device for cement kilns can achieve the purpose of large-scale substitution of coal by alternative fuels on the premise of ensuring the stable operation of the decomposition furnace.

[0025] Other features and advantages of the present invention will be described in detail in the following specific implementation section. Brief Description of the Drawings

[0026] The drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific implementation, they are used to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0027] Figure 1 is a schematic structural diagram of a multi-source heterogeneous fuel treatment device for a cement kiln;

[0028] Figure 2 is the movement state of an alternative fuel in the decomposition furnace;

[0029] Figure 3 is a process flow diagram of a multi-source heterogeneous fuel treatment device for a cement kiln;

[0030] Figure 4 is a schematic diagram of the zoning of a cement kiln.

[0031] Description of the Reference Numerals in the Drawings

[0032] 11 First Zone 12 Second Zone

[0033] 13 Third Zone 21 Screen Pipe

[0034] 22 Cyclone 23 Screen

[0035] 14 Reducing Pipe 31 High-Temperature Air Supply Pipe

[0036] 32 Feeding Chute 41 Pretreatment Furnace

[0037] 33 Gate 10 Decomposition Furnace

[0038] 42 Raw Material Feeding Pipe 35 Alternative Fuel Feeding Port Detailed Description of the Invention

[0039] The following will describe in detail the specific embodiments of the present invention with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0040] In the present invention, unless otherwise stated, directional terms included in terms such as "one end, the other end, outer surface, axis, cone, near" only represent the orientation of the term in its normal use state, or the common name understood by those skilled in the art, and should not be regarded as a limitation to the term.

[0041] A method for using a multi-source heterogeneous fuel treatment device for a cement kiln, the method comprising:

[0042] Step 1: Add alternative fuel to the multi-source heterogeneous fuel treatment device for the cement kiln, and the alternative fuel is screened in the multi-source heterogeneous fuel treatment device for the cement kiln;

[0043] Step 2: The light and small-particle alternative fuel screened in Step 1 enters the first zone 11 of the decomposition furnace 10, the heavy alternative fuel enters the pretreatment furnace 41, and the light large-particle alternative fuel enters the second zone 12 of the decomposition furnace 10;

[0044] Step 3: The fuel processed by the pretreatment furnace 41 enters the third zone 13 of the decomposition furnace 10;

[0045] Wherein the first zone 11, the second zone 12, and the third zone 13 of the decomposition furnace 10 are arranged in sequence from top to bottom along the height direction of the decomposition furnace 10.

[0046] Through the implementation of the above technical solutions, the multi-source heterogeneous fuel treatment device for the cement kiln can screen the alternative fuel. Through this screening effect, light small-particle alternative fuel, light large-particle alternative fuel, and heavy alternative fuel can be obtained. The light small-particle alternative fuel is easy to burn and has a short combustion time. Feeding it to the top of the decomposition furnace 10 can quickly burn out, effectively releasing its combustion heat value and not causing waste of heat energy; the light large-particle alternative fuel is fed into the second zone 12 in the middle of the decomposition furnace 10. In the second zone 12, the light large-particle alternative fuel burns while rising with the hot air. Since the position of the second zone 12 is relatively low, the alternative fuel in the second zone 12 can obtain more combustion time. As the light large-particle alternative fuel continues to burn, its particle size will continuously decrease. Therefore, during the continuous combustion and rising process of the light large-particle alternative fuel, its quality is also continuously increasing. By the time the light large-particle alternative fuel rises to the first zone 11, its particle size has been reduced to the same as that of the light small-particle alternative fuel. Therefore, in this way, the alternative fuel in the first zone can be homogenized, which is beneficial to the stable operation of the decomposition furnace 10.

[0047] Heavy alternative fuels usually contain undried moisture. Therefore, the heavy fuels are first fed into the pretreatment furnace 41, where the heavy fuels are dried and pre-burned to improve the quality of the alternative fuels and prevent the heavy fuels from entering the decomposition furnace 10 and affecting the operating conditions of the decomposition furnace 10. The heavy fuels treated by the pretreatment furnace 41 are fed into the third zone 13 at the bottom of the decomposition furnace 10. Considering the differences in the drying and pre-burning degrees and the water content of the heavy fuels themselves, a part of the fuels with slightly higher moisture content after drying enter the reduced-diameter pipe 14 after entering the third zone 13. As the diameter of the reduced-diameter pipe 14 becomes smaller, the cross-sectional wind speed will increase. Therefore, this part of the fuels will be affected by gases at a higher speed during the falling process and finally change the movement direction and rise with the wind. During the process, these heavy fuels move and burn in the decomposition furnace 10. Moreover, during the burning process, the moisture in the heavy fuels will be further evaporated, and at the same time, the burning will also reduce the particle size of the heavy fuels and improve the quality of the heavy fuels. Therefore, during the rising process of the heavy alternative fuels, they will successively enter the second zone 12 and the first zone 11, and at the same time, with the continuous improvement of their quality, the quality of the fuels in different regions of the decomposition furnace 10 will tend to be the same.

[0048] In summary, by screening the alternative fuels and feeding alternative fuels with different qualities to different height positions in the decomposition furnace 10, the quality of the alternative fuels in the same region of the decomposition furnace 10 can tend to be the same, which is beneficial to achieving the purpose of synchronous combustion of alternative fuels in the decomposition furnace 10, thereby ensuring the stability of the firing system. Moreover, through this control method, alternative fuels with different qualities can be completely burned in the decomposition furnace 10, achieving the purpose of maximizing the utilization of the calorific value of alternative fuels. Therefore, the use method of the multi-source heterogeneous fuel treatment device for cement kilns can achieve the purpose of large-scale substitution of coal by alternative fuels on the premise of ensuring the stable operation of the decomposition furnace 10.

[0049] In this embodiment, preferably, in step one, the alternative fuels are separated at the first stage through the screening pipeline 21. The alternative fuels are fed into the screening pipeline 21, and there is a gas moving upward in the screening pipeline 21. The heavy fuels obtained from the first-stage separation enter the pretreatment furnace 41.

[0050] The primary separation of the alternative fuel is achieved by the drag force of the gas moving upward in the sieve pipeline 21 on the alternative fuel. During the primary separation process, the moving gas generates a drag force on the alternative fuel located in the sieve pipeline 21. For the less heavy alternative fuel, the drag force it receives is greater than the gravity. Therefore, the less heavy alternative fuel will move upward together with the moving air. And for the alternative fuel with larger particles, the drag force it receives is greater. So, some heavier large-particle alternative fuels will also move upward with the gas. While for the heavy alternative fuel, the drag force in the sieve pipeline 21 is less than the gravity. Thus, they will move downward under the action of gravity, thereby realizing the separation of the heavy alternative fuel from the lighter alternative fuel, and finally being sent into the pretreatment furnace 41.

[0051] In this embodiment, preferably, the lighter alternative fuel obtained from the primary separation enters the cyclone 22 for secondary separation. The dust collection port of the cyclone 22 sends the collected medium-quality fuel into the pretreatment furnace 41, and the outlet of the cyclone 22 is communicated with the first zone 11 of the decomposition furnace 10.

[0052] The lighter alternative fuel obtained from the primary separation mainly includes light alternative fuel or alternative fuel with larger particle sizes. These alternative fuels still need to undergo secondary separation in the cyclone 22. The light alternative fuel among these alternative fuels receives a smaller centrifugal force in the cyclone and will move together with the high-temperature gas and be discharged through the outlet of the cyclone 22. The medium-quality alternative fuel that receives a larger centrifugal force is collected by the dust collection port of the cyclone 22 and conveyed into the pretreatment furnace 41.

[0053] Preferably, the temperature of the gas is set to be relatively high, so that the alternative fuel can be dried simultaneously during the process of moving together with the high-temperature gas, thereby enabling the use of this method to improve the quality of the alternative fuel while screening the alternative fuel.

[0054] In this embodiment, preferably, a sieve 23 is arranged at the position where the outlet of the cyclone 22 is connected to the first zone 11 to conduct tertiary separation on the alternative fuel. The alternative fuel with smaller particles enters the first zone 11 of the decomposition furnace 10, and the alternative fuel with larger particles enters the second zone 12 of the decomposition furnace 10 through the feeding chute 32.

[0055] After the light alternative fuel is discharged through the outlet of the cyclone 22, it still needs to be size-screened by the sieve 23.

[0056] Some alternative fuels with large particle sizes cannot pass through the screen 23. Due to their large particle sizes, the time required for complete combustion is relatively long. Therefore, they need to enter the second zone 12 to obtain a longer combustion time. During the combustion process of the light alternative fuels with large particle sizes entering the second zone 12, their particle sizes gradually decrease, and at the same time, they gradually approach the first zone 11 under the push of the gas in the decomposition furnace 10, so that these alternative fuels with large particle sizes can obtain more residence time in the decomposition furnace 10, enabling them to burn fully in the decomposition furnace 10, thus achieving the purpose of complete combustion of the alternative fuels and maximizing the utilization of the calorific value of the alternative fuels.

[0057] Some other alternative fuels with small particle sizes can burn completely quickly in the first zone 11 after passing through the screen 23. Therefore, after these light small-particle alternative fuels are sent into the first zone 11, they only need a very short time to burn completely, thus achieving the efficient utilization of the calorific value of this part of the alternative fuels.

[0058] In this embodiment, preferably, in step three, a reduced-diameter pipe 14 is provided below the third zone 13, and the alternative fuels entering the third zone 13 are separated at four levels through the reduced-diameter pipe 14.

[0059] The heavy fuel treated by the pretreatment furnace 41 will be sent into the third zone 13. A reduced-diameter pipe 14 is provided below the third zone 13. Under the action of the reduced-diameter pipe 14, the gas velocity in the third zone 13 will increase. Some alternative fuels with less water content and smaller mass are subjected to gravity less than the drag force and will move upward together with the high-temperature gas while continuously burning. As the combustion continues, the particle sizes of these alternative fuels continuously decrease, and at the same time, the water in them is evaporated, thus achieving the effect of improving the quality of the alternative fuels.

[0060] Another part of the alternative fuels with larger water content and larger mass are subjected to gravity greater than the drag force and will start to move downward. Since a reduced-diameter pipe 14 is provided below the third zone 13, as the inner diameter of the reduced-diameter pipe 14 gradually decreases, the gas velocity encountered by the alternative fuels also continuously increases. Therefore, the drag force on this part of the alternative fuels continuously increases, and as the relative movement between the alternative fuels and the high-altitude gas continues, the alternative fuels will be continuously dispersed and dried, and their mass will gradually decrease. Therefore, their self-weight will also continuously decrease. Under the condition that the self-weight decreases while the drag force increases, these alternative fuels will eventually be pushed upward by the moving gas and return to the third zone 13, and then enter the second zone until they are completely burned in the decomposition furnace 10.

[0061] During the process of the alternative fuels rising along the decomposition furnace 10, their quality is also continuously improved. When they enter different heights of the decomposition furnace 10, these alternative fuels can burn synchronously with other fuels in the decomposition furnace 10 without affecting the operating conditions of the decomposition furnace 10.

[0062] Moreover, by using this method, these alternative fuels can be respectively transported to different positions of the decomposition furnace 10 according to the different qualities of the alternative fuels, so that alternative fuels with different qualities can obtain different residence times in the decomposition furnace 10, thereby realizing that alternative fuels of various qualities can be completely burned in the decomposition furnace 10, and maximizing the utilization of the calorific value of the alternative fuels.

[0063] See Figure 1 For the described multi-source heterogeneous fuel treatment device for a cement kiln, this multi-source heterogeneous fuel treatment device for a cement kiln is connected to the decomposition furnace 10, and includes a high-temperature air supply pipe 31, a screening pipeline 21, a cyclone 22, a screen 23, a feeding chute 32, and a pretreatment furnace 41. The screening pipeline 21 is provided with an alternative fuel inlet 35. One end of the screening pipeline 21 is connected to the high-temperature air supply pipe 31, and the other end is connected to the inlet of the cyclone 22. The dust collection port of the cyclone 22 is connected to the high-temperature air supply pipe 31. The outlet of the cyclone 22 is connected to the first zone 11. The screen 23 is arranged at the connection between the cyclone 22 and the first zone 11. The high-temperature air supply pipe 31 is connected to the pretreatment furnace 41. The feeding chute 32 is connected to the second zone 12. The pretreatment furnace 41 is connected to the third zone 13;

[0064] The high-temperature air supply pipe 31 is provided with a sluice gate 33, and the air flow velocity in the screening pipeline 21 can be controlled by controlling the sluice gate 33.

[0065] The high-temperature air supply pipe 31 extracts high-temperature air from the kiln head grate cooler. Subsequently, a branch of the high-temperature air supply pipe 31 is led out as the screening pipeline 21. An alternative fuel inlet 35 is also arranged on the screening pipeline 21. The alternative fuel is added through the alternative fuel inlet 35. The added alternative fuel will move downward along the screening pipeline 21 and encounter the high-temperature gas moving upward in the screening pipeline 21. During the mutual movement of the high-temperature gas and the alternative fuel, the high-temperature gas can disperse and dry the alternative fuel, causing the alternative fuel to disperse in the screening pipeline 21. At the same time, the moving gas will also generate an upward drag force on these dispersed alternative fuels. If the drag force received by the alternative fuel is greater than its own gravity, it will move upward with the high-temperature gas. If the drag force received by the alternative fuel is less than its own gravity, it will fall along the screening pipeline 21 under the action of gravity. Therefore, in the screening pipeline 21, the primary separation of the alternative fuel can be achieved through the action of the high-temperature gas. The heavy alternative fuel will fall into the lower high-temperature air supply pipe 31 path, while the lighter alternative fuel will move upward with the high-temperature gas.

[0066] Preferably, the screening pipeline 21 is arranged in the height direction, so that the added alternative fuel will not slide down along the side wall of the screening pipeline 21, but will move downward in the screening pipeline 21 and can be in full contact with the high-temperature gas during the movement, which is beneficial to the dispersion of the high-temperature gas to the alternative fuel. At the same time, it also enables the high-temperature gas to generate a greater drag force on the alternative fuel, which is beneficial to improving the separation efficiency of the primary separation.

[0067] The lighter alternative fuel obtained by the primary separation enters the cyclone 22 along with the high-temperature gas and undergoes secondary separation in the cyclone 22. Under the action of the cyclone 22, the light alternative fuel can flow out from the outlet along with the high-temperature gas, while the heavier medium alternative fuel will be collected by the dust collection port and sent into the high-temperature air supply pipe 31.

[0068] The light alternative fuel that does not contain moisture can be directly sent into the decomposition furnace 10 for combustion. However, for the light fuel, due to the different particle sizes of the fuel, the burning time required in the decomposition furnace 10 is also different. Therefore, a screen 23 is provided at the connection between the cyclone 22 and the first zone 11 of the decomposition furnace 10. Through the filtering action of the screen 23, the light alternative fuel with smaller particles will enter the first zone 11 of the decomposition furnace 10 for rapid combustion. In the first zone 11, the light small-particle alternative fuel can be quickly burned out and release its heat energy. The light fuel with larger particle sizes cannot pass through the screen 23 and will enter the second zone 12 of the decomposition furnace 10 through the feed chute 32. The burning time required for the light fuel with larger particle sizes is greater than that required for the light fuel with smaller particle sizes. Therefore, after these alternative fuels with larger particle sizes are sent into the second zone 12, they can burn while moving upward along with the gas in the decomposition furnace 10, so as to obtain more burning time and enable them to burn fully in the decomposition furnace 10 and effectively release their calorific value.

[0069] Preferably, a flared opening is provided at the position of the feed chute 32 close to the screen 23. By setting the flared opening, the alternative fuel with larger particle sizes that do not pass through the screen 23 can be reliably collected. Moreover, under the guiding action of the flared opening, these alternative fuels can smoothly move downward along the feed chute 32.

[0070] During the screening process of the alternative fuel, when the alternative fuel is mixed with the high-temperature gas and moves together, the high-temperature gas will dry these alternative fuels, thus achieving the effect of improving the quality of the alternative fuel.

[0071] The high-temperature air delivery pipe 31 is connected to the pretreatment furnace 41. The heavy alternative fuel entering the high-temperature air delivery pipe 31 usually contains relatively more moisture. Through the drying and pre-combustion in the pretreatment furnace 41, the moisture in the heavy alternative fuel can be effectively removed. Moreover, the particle size of the heavy alternative fuel after pre-combustion will also relatively decrease, and the quality of the fuel can be improved. These alternative fuels processed by the pretreatment furnace 41 are sent to the third zone 13 of the decomposition furnace 10, where these alternative fuels can obtain the longest combustion time in the third zone 13 of the decomposition furnace 10.

[0072] Considering the combustion stability of alternative fuels with different qualities after screening and the corresponding residence time required in the decomposition furnace 10, the space of the decomposition furnace 10 is allocated. The decomposition furnace 10 is divided into a first zone 11, a second zone 12, and a third zone 13. The height of the access position of the third zone 13 is H1, usually taking the height of the lowest point of the access position, and the same below; the height of the access position of the second zone 12 is H2, and the height of the access position of the first zone 11 is H3. Among them, the 0m plane for reference of H1, H2, and H3 is set as the highest point of the square-to-round structure, and the height of H1 is equal to the height of the variable diameter part of the decomposition furnace 10. At the same time, (H1 + H2) / (H3 - H2) = G CPF / G 下料溜管 ,G CPF represents the weight of the alternative fuel entering the pretreatment furnace 41 per unit time, and G 下料溜管 represents the weight of the alternative fuel passing through the feeding chute 32 per unit time.

[0073] The alternative fuel entering the decomposition furnace 10 from the pretreatment furnace 41 may first move downward, and can move at most to the position where the square-to-round structure is connected to the decomposition furnace 10. After that, the alternative fuel starts to move upward with the hot air and moves with the high-temperature gas until it reaches the access position of the second zone 12. During the whole process, the alternative fuel entering from the pretreatment furnace 41 can usually move within the range of H1 + H2.

[0074] After the light large-particle alternative fuel entering from the feeding chute 32 enters the second zone 12 of the decomposition furnace 10, it will move upward with the high-temperature gas until it reaches the access position of the first zone 11. During the whole process, the alternative fuel entering from the feeding chute 32 can move within the range of H3 - H2.

[0075] According to the main component ratio of the added alternative fuel, the decomposition furnace 10 can be reasonably partitioned, and the positions of H1, H2, and H3 on the decomposition furnace 10 can be determined specifically.

[0076] The total mass of the added alternative fuel is G, the weight of the alternative fuel entering the pretreatment furnace 41 is G CPF ,and the weight of the alternative fuel passing through the feeding chute 32 is G 下料溜管 ,and the weight of the alternative fuel passing through the screen 23 is G筛网 , the relationships between the variables are as follows:

[0077] G = G CPF + G 筛网 + G 下料溜管

[0078] G CPF = G × η 一级分离效率 + G × (1 - η 一级分离效率 ) × η 二级分离效率

[0079] G 筛网 = G × (1 - η 一级分离效率 ) × (1 - η 二级分离效率 ) × η 筛网通过率

[0080] G 下料溜管 = G × (1 - η 一级分离效率 ) × (1 - η 二级分离效率 ) × (1 - η 筛网通过率 )

[0081] Among them, η represents the separation efficiency of each separation stage, η 一级分离效率 represents the percentage of the mass of the heavy alternative fuel obtained from the primary separation to the total mass of the alternative fuel input at the alternative fuel inlet 35; η 二级分离效率 represents the percentage of the mass of the medium-quality fuel obtained from the secondary separation to the total mass of the alternative fuel added to the cyclone 22, η 筛网通过率 represents the percentage of the mass of the light small-particle alternative fuel passing through the screen 23 to the mass of the alternative fuel at the outlet of the cyclone 22.

[0082] The high-temperature air supply pipe 31 is provided with a shutter 33, and the air flow velocity in the screen pipe 21 can be controlled by controlling the shutter 33.

[0083] The shutter 33 is arranged behind the connection position of the screen pipe 21 and the high-temperature air supply pipe 31, and the air volume entering the rear high-temperature air supply pipe 31 can be controlled by controlling the shutter 33.

[0084] If the opening of the control gate 33 becomes larger, the air volume entering the rear high-temperature air duct 31 increases. Correspondingly, the air volume entering the sieve duct 21 decreases, and the air flow velocity in the sieve duct 21 also decreases. Then, the drag force generated by the air flow on the alternative fuel will also decrease accordingly. Less lighter alternative fuel can be obtained through primary separation. The lighter alternative fuel that moves with the gas after primary separation will enter the cyclone 22 for secondary separation. Since the wind speed entering the cyclone 22 becomes smaller, the centrifugal force in the cyclone becomes smaller, and less light alternative fuel can rotate with the gas to the outlet of the cyclone 22. Correspondingly, less light fuel will enter the tertiary separation. Then, the amount of light small-particle alternative fuel entering the first zone 11 of the decomposition furnace 10 will decrease accordingly. Therefore, when the opening of the gate 33 becomes larger, the amount of alternative fuel entering the first zone 11 will decrease. On the contrary, when the opening of the gate 33 becomes smaller, the amount of alternative fuel entering the first zone 11 will increase.

[0085] Since the air volume of the sieve duct 21 decreases, the amount of heavy alternative fuel obtained through primary separation will increase. Therefore, more alternative fuel enters the pretreatment furnace 41, that is, when the opening of the gate 33 becomes larger, more alternative fuel enters the pretreatment furnace 41. On the contrary, when the opening of the gate 33 becomes smaller, less alternative fuel enters the pretreatment furnace 41.

[0086] When the air volume of the sieve duct 21 decreases, the amount of light fuel entering the tertiary separation will decrease, and then the amount of light large-particle alternative fuel falling into the feed chute 32 will decrease, that is, the amount of alternative fuel entering the second zone 12 of the decomposition furnace 10 decreases. On the contrary, when the opening of the gate 33 becomes smaller, more alternative fuel enters the second zone 12.

[0087] When the opening of the gate 33 becomes larger, while more alternative fuel enters the pretreatment furnace 41, the high-temperature gas entering the pretreatment furnace 41 also increases. Therefore, when the opening of the gate 33 becomes larger, more high-temperature gas in the pretreatment furnace 41 can dry and preheat the alternative fuel, thereby reliably improving the quality of the alternative fuel in the pretreatment furnace 41.

[0088] In summary, by controlling the opening size of the gate 33, the amount of alternative fuel entering the first zone 11, the second zone 12, and the third zone 13 can be distributed.

[0089] Preferably, a pressure sensor is arranged in the high-temperature air duct 31 behind the gate 33. The pressure in the high-temperature air duct 31 behind the gate 33 is detected by this pressure sensor, and the air distribution volume of the high-temperature air duct 31 can be monitored according to the pressure value in the high-temperature air duct 31 at this position.

[0090] Preferably, the temperature at the outlet of the decomposition furnace 10 is set to 880 °C. By adjusting the size of the opening of the shutter 33, the temperature at the outlet of the decomposition furnace 10 can be adjusted. When the temperature at the outlet of the decomposition furnace 10 is relatively high, higher than 880 °C, the opening of the shutter 33 can be enlarged, so that less alternative fuel enters the first zone 11. Since the first zone 11 is close to the outlet of the decomposition furnace 10, reducing the amount of alternative fuel input into the first zone 11 can significantly reduce the temperature at the outlet of the decomposition furnace 10. Conversely, by reducing the size of the opening of the shutter 33, the amount of alternative fuel input into the first zone 11 can be increased, and then the temperature at the outlet of the decomposition furnace 10 can be appropriately increased.

[0091] In this embodiment, preferably, the air temperature in the high-temperature air duct 31 is 950 - 1150 °C.

[0092] The high-temperature air duct 31 can extract high-temperature air from the kiln head grate cooler. The outlet temperature of the kiln head grate cooler is approximately 1050 °C. These high-temperature gases can not only separate the alternative fuel in the sieve pipeline 21 but also pre-treat the heavy alternative fuel in the pre-treatment furnace 41.

[0093] The temperature in the pre-treatment furnace 41 needs to be maintained at 800 - 1000 °C. Therefore, setting the air temperature in the high-temperature air duct 31 to 950 - 1150 °C can meet the temperature requirements of the pre-treatment furnace 41.

[0094] Preferably, an air cannon is provided in the pre-treatment furnace 41 to blow the alternative fuel, so that the alternative fuel in the pre-treatment furnace 41 can reliably enter the third zone 13. Moreover, blowing in the pre-treatment furnace 41 is also beneficial to the dispersion of the alternative fuel and can accelerate the drying and pre-combustion of the alternative fuel in the pre-treatment furnace 41. By adjusting the blowing frequency of the air cannon, the residence time of the alternative fuel in the pre-treatment furnace 41 can be adjusted. The higher the blowing frequency of the air cannon, the shorter the residence time of the alternative fuel in the pre-treatment furnace 41, and the lower the blowing frequency of the air cannon, the longer the residence time of the alternative fuel in the pre-treatment furnace 41.

[0095] The alternative fuel contacts the high-temperature gas in the pre-treatment furnace 41. Through heat exchange, the alternative fuel will quickly heat up and achieve the effects of drying and preheating during the heating process. Therefore, the length of the residence time in the pre-treatment furnace 41 affects the quality of the alternative fuel entering the third zone 13. By extending the residence time of the alternative fuel in the pre-treatment furnace 41, the quality of the alternative fuel entering the third zone 13 can be improved. Correspondingly, if the residence time of the alternative fuel in the pre-treatment furnace 41 is reduced, the alternative fuel may have a larger particle size or excessive moisture when entering the third zone 13.

[0096] Prolonging the residence time of the alternative fuel in the pretreatment furnace 41 will result in an increase in the storage amount of the alternative fuel in the pretreatment furnace 41, while the amount of high-temperature gas in the pretreatment furnace 41 remains unchanged. Therefore, it may cause the temperature in the pretreatment furnace 41 to decrease. A decrease in the temperature in the pretreatment furnace 41 will affect the treatment effect of the alternative fuel in the pretreatment furnace 41. Therefore, the temperature in the pretreatment furnace 41 needs to be maintained at 800 - 1000 °C.

[0097] Preferably, a temperature sensor is provided in the pretreatment furnace 41. When the temperature in the pretreatment furnace 41 is lower than 800 °C, the blowing frequency of the air cannon can be increased to quickly move the alternative fuel in the pretreatment furnace 41 into the decomposition furnace 10. After the alternative fuel is ejected, the high-temperature gas in the high-temperature air supply pipe 31 can play a role in heating the pretreatment furnace 41.

[0098] After these alternative fuels with lower quality enter the decomposition furnace 10, due to their large particle size and high moisture content, they cannot be pushed upward by the high-temperature gas in the decomposition furnace 10 and will fall. Under the action of the lower constriction pipe 14, the flow rate of the high-temperature gas at this position gradually increases, and the drag force on these alternative fuels will also increase, and finally these alternative fuels will be pushed upward. During the process of these alternative fuels descending and then rising, the moisture inside the alternative fuels is effectively evaporated, and as combustion progresses, their particle size will also decrease. Therefore, the quality of the alternative fuels is improved.

[0099] When the temperature in the pretreatment furnace 41 is higher than 1000 °C, the blowing frequency of the air cannon can be reduced to prolong the residence time of the alternative fuel in the pretreatment furnace 41. As time goes on, the alternative fuels entering the pretreatment furnace 41 with the high-temperature gas in the high-temperature air supply pipe 31 will continuously increase. Under the action of these alternative fuels, the temperature in the pretreatment furnace 41 will decrease somewhat.

[0100] In summary, by adjusting the blowing frequency of the air cannon, the temperature of the pretreatment furnace 41 can be adjusted to a first degree.

[0101] In this embodiment, preferably, a three-way valve is provided on the feed chute 32, and the three-way valve controls the feed chute 32 to be connected to the second zone 12 of the decomposition furnace 10 and the pretreatment furnace 41 respectively.

[0102] A three-way valve is provided on the feed chute 32. Through this three-way valve, the light and large-particle alternative fuels in the feed chute 32 can enter the second zone 12 or the pretreatment furnace 41.

[0103] When the light large-particle alternative fuel enters the second zone 12, the combustion of these alternative fuels can provide heat for the precalciner 10. However, when the temperature in the pretreatment furnace 41 is insufficient, the three-way valve can be controlled to send these alternative fuels into the pretreatment furnace 41. After these light large-particle fuels enter the pretreatment furnace 41, the fuel raises the temperature of the pretreatment furnace 41.

[0104] These light large-particle alternative fuels are flammable. Therefore, sending these alternative fuels into the pre-combustion furnace can quickly raise the temperature of the pretreatment furnace 41. Moreover, even if these light large-particle alternative fuels do not burn completely in the preheating furnace, they can enter the third zone 13 of the precalciner 10 and continue to burn until they are completely burned out. Therefore, there will be no problem of calorific value loss or waste.

[0105] In this embodiment, preferably, the pretreatment furnace 41 further includes a raw meal feeding pipe 42 for cooling the pretreatment furnace 41, and a raw meal control valve is provided on the raw meal feeding pipe 42.

[0106] When the temperature in the pretreatment furnace 41 is relatively high, for safety production considerations, it is necessary to cool down the pretreatment furnace 41. Adding raw meal into the pretreatment furnace 41 through the raw meal feeding pipe 42 can cool down the pretreatment furnace 41. The raw meal added to the pretreatment furnace 41 will enter the precalciner 10 together with the alternative fuel in the pretreatment furnace 41. Therefore, the added raw meal will still return to the precalciner 10, and there will be no situation of material discharge. At the same time, under the action of the high-temperature environment in the pretreatment furnace 41, the raw meal can absorb heat and decompose sufficiently, and there will be no problem of reduced decomposition rate caused by raw meal short-circuit.

[0107] Preferably, the cyclone 22 is also provided with a raw meal feeding pipe 42. When the temperature in the cyclone 22 is too high, raw meal can also be added to the cyclone 22 to cool it down. The raw meal added to the cyclone 22 will enter the lower pretreatment furnace 41 from the dust collection port after being separated by the cyclone 22, and enter the precalciner 10 together with the alternative fuel in the pretreatment furnace 41. Therefore, the added raw meal will still return to the precalciner 10, and there will be no situation of material discharge and reduced decomposition rate.

[0108] In this embodiment, preferably, the temperature in the pretreatment furnace 41 is set to 800 - 1000 °C. A temperature sensor for detecting the temperature in the pretreatment furnace 41 is provided in the pretreatment furnace 41, and the temperature sensor is electrically connected to the three-way valve and the raw meal control valve.

[0109] When the temperature of the pretreatment furnace 41 is within the normal operating range, both the three-way valve and the raw material control valve are in the closed state. When the temperature inside the pretreatment furnace 41 is higher than 1000 °C, the raw material control valve is opened, and raw materials are added to the pretreatment furnace 41 to cool down the pretreatment furnace 41; when the temperature inside the pretreatment furnace 41 is lower than 800 °C, the three-way valve is opened to control the light large particle alternative fuel in the feeding chute 32 to enter the pretreatment furnace 41 for combustion to heat up the pretreatment furnace 41.

[0110] Preferably, a temperature sensor is also provided inside the cyclone 22 to monitor the temperature of the cyclone 22. At the same time, a raw material control valve is also provided for the cyclone 22 to adjust the temperature inside.

[0111] The preferred embodiments of the present invention have been described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0112] In addition, it should be noted that, in the above specific embodiments, the various specific technical features described can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0113] In addition, any combination can be made between various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A method for using a multi-source heterogeneous fuel treatment device for a cement kiln, characterized in that, The usage method includes: Step 1: Add the alternative fuel into the multi-source heterogeneous fuel treatment device of the cement kiln, and the alternative fuel is screened in the multi-source heterogeneous fuel treatment device of the cement kiln; Step 2: The light and small-particle alternative fuels screened in Step 1 enter the first zone (11) of the decomposition furnace (10), the heavy alternative fuels enter the pretreatment furnace (41), and the light large-particle alternative fuels enter the second zone (12) of the decomposition furnace (10); Step 3: In Step 2, the alternative fuel treated by the pretreatment furnace (41) enters the third zone (13) of the decomposition furnace (10); Among them, the first zone (11), the second zone (12), and the third zone (13) of the decomposition furnace (10) are distributed from top to bottom along the height direction of the decomposition furnace (10).

2. The usage method according to claim 1, wherein In Step 1, the alternative fuel is subjected to primary separation through the screening pipeline (21). The alternative fuel enters the screening pipeline (21), and there is a gas moving upward in the screening pipeline (21). The heavy fuel obtained from the primary separation enters the pretreatment furnace (41).

3. The usage method according to claim 2, characterized in that, The lighter alternative fuel obtained from the primary separation enters the cyclone (22) for secondary separation. The dust collection port of the cyclone (22) sends the collected medium-quality alternative fuel into the pretreatment furnace (41), and the outlet of the cyclone (22) is connected to the first zone (11) of the decomposition furnace (10).

4. The usage method according to claim 3, characterized in that A screen (23) is provided at the connection position between the outlet of the cyclone (22) and the first zone (11) for tertiary separation of the alternative fuel. The smaller-particle alternative fuel obtained from the separation enters the first zone (11) of the decomposition furnace (10), and the larger-particle alternative fuel obtained from the separation enters the second zone (12) of the decomposition furnace (10) through the feeding chute (32).

5. The usage method according to claim 3, characterized in that, In Step 3, a reduced-diameter pipe (14) is provided below the third zone (13), and the alternative fuel entering the third zone (13) is subjected to quaternary separation through the reduced-diameter pipe (14).

6. A cement kiln multi-source heterogeneous fuel treatment device used in the usage method according to any one of claims 4-5, characterized in that, The multi-source heterogeneous fuel treatment device of the cement kiln is connected to the decomposition furnace (10), including an alternative fuel inlet (35), a high-temperature air supply pipe (31), a screening pipeline (21) connected to the high-temperature air supply pipe (31), a cyclone (22), a screen (23), a feeding chute (32), and a pretreatment furnace (41). The screening pipeline (21) is connected to the inlet of the cyclone (22), the dust collection port of the cyclone (22) is connected to the high-temperature air supply pipe (31), the outlet of the cyclone (22) is connected to the first zone (11), the screen (23) is arranged at the connection between the cyclone (22) and the first zone (11), the high-temperature air supply pipe (31) is connected to the pretreatment furnace (41), the feeding chute (32) is connected to the second zone (12), and the pretreatment furnace (41) is connected to the third zone (13); The high-temperature air supply pipe (31) is provided with a gate (33), and the air flow velocity in the screening pipeline (21) can be controlled by controlling the gate (33).

7. The multi-source heterogeneous fuel treatment device for a cement kiln according to claim 6, characterized in that The air temperature in the high-temperature air supply pipe (31) is 950 - 1150 °C.

8. The cement kiln multi-source heterogeneous fuel treatment device according to claim 6, characterized in that, A three-way valve is provided on the feeding chute (32), and the three-way valve controls the feeding chute (32) to be respectively connected to the second zone (12) of the decomposition furnace (10) and the pretreatment furnace (41).

9. The multi-source heterogeneous fuel treatment device for a cement kiln according to claim 8, characterized in that, Inside the pretreatment furnace (41), there is a raw material addition pipe (42) for cooling the pretreatment furnace (41), and the raw material addition pipe (42) is provided with a raw material control valve.

10. The cement kiln multi-source heterogeneous fuel treatment device according to claim 9, characterized in that, The temperature inside the pretreatment furnace (41) is set to 800 - 1000 °C. Inside the pretreatment furnace (41), there is a temperature sensor for detecting the temperature inside the pretreatment furnace (41), and the temperature sensor is electrically connected to a three-way valve and a raw material control valve.

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