Combustion atmosphere and temperature controllable alternative fuel pre-combustion furnace and combustion method

Abstract

The invention relates to the technical field of cement industrial kiln systems, and particularly discloses a combustion atmosphere and temperature controllable alternative fuel pre-combustion furnace and a combustion method. Comprising a combustion chamber provided with a feeding port and a hot air inlet, a sealing cover matched with the combustion chamber to form a cavity, a stepped material distribution bed installed in the cavity, a material pushing device used for overturning and pushing alternative fuel on the stepped material distribution bed, a combustor arranged on the combustion chamber and a raw material inlet used for conveying raw materials into the combustion chamber. And the combustion chamber is connected with the decomposing furnace. According to the invention, the combustion temperature of the combustion chamber can be effectively regulated and controlled, the combustion temperature in the combustion chamber is prevented from being too high or too low, and the material pushing device is combined to overturn and convey substitute materials spread on the stepped material distribution bed from the feeding port, so that sufficient combustion is effectively realized, and secondary pollution caused by leakage of harmful derivatives is avoided; and external air is prevented from entering the combustion chamber, so that the combustion atmosphere is effectively controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of cement industrial kiln systems, and more particularly to an alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature and a combustion method. Background Art

[0002] The combustion atmosphere refers to the ratio of oxidant to inert components during the combustion process.

[0003] Combustion temperature refers to the temperature inside the furnace during the combustion process.

[0004] Alternative fuels used in cement kiln decomposition furnaces include renewable energy and waste, such as biomass fuels, garbage, coal gangue, etc. These alternative fuels usually have higher calorific value and relatively stable combustion performance, and can partially or completely replace traditional fossil fuels, such as coal and oil, and are widely used in industrial production and power generation. Because cement kilns have unique advantages of high temperature and alkaline environment, they have become an important way to recycle and harmlessly dispose of alternative fuels.

[0005] The combustion atmosphere and temperature of alternative fuels have an important impact on the cement kiln system. For example, in the full oxygen combustion of cement kilns, a component close to pure oxygen (oxygen concentration above 90%) is required as the oxidant source. If outside air enters the system during the combustion process, it will destroy the atmosphere of full oxygen combustion, change the calcination reaction of the materials in the kiln, and have an adverse effect on the system. The pre-combustion furnaces in the prior art will introduce external air into the combustion chamber, which cannot meet the requirements of full oxygen combustion of cement kilns; such as:

[0006] Air cannons are used to release compressed air to propel materials. When a large amount of compressed air enters the kiln system, it is very easy to cause combustion fluctuations of coal powder, which directly affects the thermal balance stability of the clinker burning system.

[0007] The mechanical device is used to extend into the furnace body to force the material to move. The gap between the furnace body holes and the mechanical device will cause external air to enter the kiln system, affecting the thermal balance stability of the clinker burning system. In addition, the gap will also become a channel for material leakage, causing secondary pollution;

[0008] At the same time, the existing technology does not control the combustion temperature in the combustion chamber; if the combustion temperature is too low, the combustion is incomplete, resulting in energy waste and increased pollutant emissions. Low-temperature incineration cannot ensure the decomposition of nitrogen oxides, resulting in sulfur dioxide generating hydrogen sulfide, which in turn generates corrosive substances, causing corrosion to equipment; if the combustion temperature is too high, certain organic matter will decompose to produce harmful substances such as dioxins, and will increase the volatilization of metals and the increase of chlorine oxide content, causing secondary pollution. Summary of the invention

[0009] The technical problem to be solved by the present invention is to provide a pre-combustion furnace for alternative fuels and a combustion method with controllable combustion atmosphere and temperature;

[0010] The solution adopted by the present invention to solve the technical problem is:

[0011] A pre-combustion furnace for alternative fuels with controllable combustion atmosphere and temperature, comprising a combustion chamber provided with a feeding port and a hot air inlet, a sealing cover installed at the bottom of the combustion chamber and cooperating with the combustion chamber to form a chamber, a stepped material bed installed in the chamber and in a stepped shape, a pushing device installed outside the sealing cover and having one end extending into the chamber to flip and push the alternative fuel on the stepped material bed, a burner arranged on the combustion chamber and used for fuel injection, and a raw material inlet for conveying raw material into the combustion chamber; the injection direction of the fuel is the same as the movement direction of the alternative fuel; and the combustion chamber is connected to a decomposition furnace.

[0012] In some possible embodiments, the pushing device includes a pushing head that slides with the stepped material bed, a pushing rod with one end connected to the pushing head and the other end located outside the sealing cover, and a driving device connected to the end of the pushing rod away from the pushing head and used to control the pushing rod to make linear reciprocating motion along its axial direction; a sealing structure that seals with the push rod and allows the push rod to pass through is provided on the sealing cover.

[0013] In some possible implementations, the sealing structure includes a sealing box installed outside the sealing cover and arranged corresponding to the push rod, and a sealing filler arranged in the sealing box and located between the sealing box and the push rod.

[0014] In some possible implementations, the stepped material distribution bed is inclined and the angle formed by the stepped material distribution bed and the horizontal plane is 20-40°;

[0015] The stepped material distribution bed includes a plurality of receiving platforms arranged in sequence from top to bottom and located in the chamber, and a connecting plate arranged between two adjacent receiving platforms; the pusher head is located between two adjacent receiving platforms; and a hole for the pusher head to pass through is arranged on the connecting plate.

[0016] In some possible implementations, there are multiple groups of pusher heads in each group of the pushing device, and they are respectively connected to the push rods; the multiple groups of pusher heads are arranged at equal intervals along the vertical direction.

[0017] In some possible implementations, an ash discharge port is provided at the bottom of the sealing cover and below the stepped material bed, and an air lock valve is provided on the ash discharge port.

[0018] In some possible embodiments, the feeding port is located above the stepped material bed, and a spiral air-locking feeding device is provided on the feeding port; the hot air inlet, raw material inlet, and burner are all located above the stepped material bed and at one end of the stepped material bed close to the feeding port.

[0019] In some possible implementations, the top of the combustion chamber is an arc-shaped structure, and refractory castables are arranged in the side walls of the combustion chamber.

[0020] A combustion method for an alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to the above, specifically comprising the following steps:

[0021] The alternative fuel is fed into the combustion chamber from the feed port and spread onto the stepped material bed. The hot air inlet introduces heat source and combustion-supporting gas from the tertiary air of the cement kiln system to heat and burn the alternative fuel.

[0022] During the combustion process of the alternative fuel, the alternative fuel is continuously pushed by the pushing device and turned and transported downward along the stepped material bed, and the temperature in the combustion chamber is adjusted by providing fuel into the combustion chamber through the burner or providing raw meal into the combustion chamber through the raw meal inlet, so as to achieve full combustion of the alternative fuel;

[0023] After the alternative fuel is fully burned, the ash falls from the discharge port of the combustion chamber into the decomposition furnace connected to the combustion chamber as an admixture, completing the treatment of the alternative fuel;

[0024] The alternative fuel dropped during the alternative fuel turning process will be collected in the ash discharge port.

[0025] In some possible embodiments, during the combustion of the alternative fuel, when the monitored combustion chamber temperature is lower than 850° C., the fuel is injected into the combustion chamber through the burner to increase the combustion chamber temperature;

[0026] During the combustion of alternative fuels, when the monitored combustion chamber temperature is higher than 1100°C, low-temperature raw meal enters the combustion chamber from the raw meal inlet to cool the combustion chamber.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The present invention uses a hot air inlet to bring in heat source and combustion-supporting gas from the tertiary air of the cement kiln system to heat and burn the substitute material. During the combustion process, fuel is supplied into the combustion chamber by a burner to increase the temperature in the combustion chamber. Low-temperature raw materials are supplied into the combustion chamber through a raw material inlet to reduce the temperature in the combustion chamber, thereby avoiding excessively high or low combustion temperatures in the combustion chamber. In combination with a pushing device, the substitute material spread on the stepped material bed from the feeding port is turned over and transported, thereby effectively achieving full combustion of the substitute material and avoiding secondary pollution caused by leakage of harmful derivatives. The entire device will form a sealed chamber, and external air will not be introduced during combustion. It can be used in conjunction with the full oxygen combustion of the cement kiln, and will not destroy the atmosphere of the full oxygen combustion and change the calcination reaction of the material in the kiln.

[0029] The present invention prevents air from entering the device and affecting the combustion temperature during the combustion process by arranging a sealing cover connected to the combustion chamber and a sealing structure at the bottom of the stepped material bed, and also prevents material leakage.

[0030] The present invention effectively avoids airflow dead zones by arranging the top of the combustion furnace as an arc-shaped structure, thereby making the furnace temperature uniform and stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural schematic diagram of the present invention;

[0032] Figure 2 It is a schematic diagram of the connection relationship between the stepped material bed, the sealing cover, the sealing structure and the push rod in the present invention;

[0033] Figure 3 for Figure 2 The enlarged schematic diagram of point A in the middle;

[0034] Figure 4 It is a structural schematic diagram of the material pushing device in the present invention;

[0035] Figure 5 It is a structural schematic diagram of the combustion chamber and the raw meal inlet in the present invention;

[0036] Wherein: 1. combustion chamber; 101. top; 102. refractory castable; 2. hot air inlet; 3. spiral air-locking feeding device; 4. stepped material bed; 5. burner; 6. pushing device; 61. bracket; 62. driving device; 63. push rod; 64. push head; 65. supporting wheel; 66. pressure wheel; 7. sealing cover; 8. discharge port; 9. ash discharge port; 10. raw material inlet; 11. decomposition furnace; 12. sealing structure; 121. sealing box; 122. sealing filler. DETAILED DESCRIPTION

[0037] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. The "first", "second" and similar words mentioned in this application do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "one" or "one" and other similar words do not indicate a quantity restriction, but indicate the existence of at least one. In the implementation of this application, "and / or" describes the association relationship of the associated objects, indicating that there can be three relationships, for example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In the description of the embodiments of the present application, unless otherwise specified, the meaning of "multiple" refers to two or more. For example, multiple positioning columns refer to two or more positioning columns. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0038] The present invention is described in detail below.

[0039] like Figure 1-Figure 5 As shown:

[0040] A pre-combustion furnace for alternative fuels with controllable combustion atmosphere and temperature, comprising a combustion chamber 1 provided with a feed port and a hot air inlet 2, a sealing cover 7 installed at the bottom of the combustion chamber 1 and cooperating with the combustion chamber 1 to form a chamber, a stepped material bed 4 installed in the chamber and in a stepped shape, a pushing device installed outside the sealing cover 7 and having one end extending into the chamber to overturn and push the alternative fuel spread on the stepped material bed 4, a burner 5 installed on the combustion chamber 1 and used for fuel injection, and a raw material inlet 10 for conveying raw material into the combustion chamber 1; the injection direction of the fuel is the same as the moving conveying direction of the alternative fuel; the combustion chamber 1 is connected to a decomposition furnace 11;

[0041] Before use, the hot air inlet 2 of the device is connected to the cement kiln, so that high-temperature tertiary air is introduced as a heat source and combustion-supporting gas through the hot air inlet 2; specifically, high-temperature tertiary air from the cement kiln is introduced as a heat source and combustion-supporting gas through the hot air inlet 2. The "tertiary air" here refers to the preheated waste gas extracted from the cooler during the cement production process. It not only has a high temperature, but also contains a specific proportion of oxygen, which can effectively improve the combustion efficiency; it makes full use of the waste heat resources in the cement production process, which saves energy and is environmentally friendly.

[0042] The alternative fuel enters the combustion chamber 1 through the feed port and is spread on the stepped material bed 4 and mixed with the combustion-supporting gas for full combustion, thereby avoiding secondary pollution caused by the generation of harmful derivatives due to incomplete combustion;

[0043] During combustion, the alternative fuel spread on the stepped material bed 4 is turned over by the pushing device 6 and transported from top to bottom, so that the alternative material is fully burned, and the fully burned material enters the decomposition furnace 11; the sealing cover 7 is set so that during combustion, the outside air cannot enter the combustion chamber 1, and at the same time, the entire device will not leak, thereby avoiding leakage;

[0044] The burner 5 will spray fuel when the temperature of the combustion chamber 1 is low to increase the temperature of the combustion chamber 1; and the raw material inlet 10 will introduce relatively low-temperature raw materials when the temperature of the combustion chamber 1 is high to cool the combustion chamber 1, thereby ensuring that the temperature of the combustion chamber 1 is controlled within a reasonable range, thereby achieving full combustion of the alternative fuel; the sealing cover 7 is connected to the combustion chamber 1, and completely covers the pusher head 64 of the pusher device 6 and the stepped distribution bed 4 to form a sealed cavity to prevent external air from entering the cement kiln system from the gap between the pusher device 6 and the stepped distribution bed 4;

[0045] By setting the fuel injection direction consistent with the conveying direction of the substitute material, the fuel and the substitute material can be moved synchronously and in the same direction, thereby achieving full combination with the substitute material.

[0046] In some possible embodiments, in order to effectively flip and transport the materials spread on the stepped material bed 4; the pushing device 6 includes a pushing head 64 that slides with the stepped material bed 4 and is located in the chamber, a push rod 63 with one end connected to the pushing head 64 and the other end located outside the sealing cover 7, and a driving device 62 that is connected to the end of the push rod 63 away from the pushing head 64 and is used to control the push rod 63 to make a linear reciprocating motion along its axial direction; a sealing structure 12 that seals with the push rod 63 and allows the push rod 63 to pass through is provided on the sealing cover 7; the push rod 63 slides with the sealing structure 12.

[0047] The stepped material bed 4 is inclined and the angle formed with the horizontal plane is 20-40°; this allows the substitute material entering from the feeding port to be effectively spread on the stepped material bed 4;

[0048] The step material bed 4 includes a plurality of receiving platforms arranged sequentially from top to bottom and located in the chamber, and a connecting plate arranged between two adjacent receiving platforms; the pusher head 64 is located between two adjacent receiving platforms; a hole for the pusher head 64 to pass through is arranged on the connecting plate; the receiving platform is arranged horizontally;

[0049] Multiple groups of receiving platforms will form a stepped structure, and two adjacent groups of receiving platforms are connected by a connecting plate to form a stepped material distribution bed 4;

[0050] Furthermore, multiple groups of pushing devices 6 are arranged at equal intervals in the vertical direction;

[0051] Each set of pusher heads 64 will be located between two adjacent sets of receiving platforms and pass through the holes provided on the connecting plate to fit with the gaps in the holes to avoid interference between the pusher heads 64 and the holes.

[0052] When the alternative material needs to be turned over and conveyed downward, the driving device 62 controls the push rod 63 to move toward the combustion chamber 1, thereby driving the push head 64 to move away from the push rod 63, so that the material on the corresponding receiving platform moves away from the push head 64, thereby realizing the downward conveyance and turning of the alternative material on the receiving platform;

[0053] The driving device 62 may be a cylinder, an electric cylinder, or other linear driving device 62, which can effectively control the push rod 63 to perform linear reciprocating motion along its axial direction; its internal structure will not be described in detail here;

[0054] Specifically, during operation, the push rod 63 above a certain group of receiving platforms moves forward, and at the same time, the push rod 63 below the group of receiving platforms moves back, so that the substitute material on the receiving platform is pushed by the push head 64 on the group of receiving platforms and flipped onto the lower receiving platform; then, the push head 64 on the lower receiving platform moves forward, and continues to push the lifted material to flip it onto the next layer; this cycle is repeated to form, thereby pushing the substitute material to continuously flip, fully burn, and transport it from top to bottom.

[0055] Furthermore, the pusher head 64 is in direct contact with the burning substitute material and is made of heat-resistant steel.

[0056] Furthermore, in order to ensure the support and guidance of the corresponding push head 64 and the push rod 63, a support wheel 65 is provided in the sealing cover 7, which is slidably matched with the push head 64 and is used to support the push head 64; a bracket 61 for installing the drive device 62 is provided on the outer side of the sealing cover 7; a support wheel 65 and a pressure wheel 66 used in conjunction with the push rod 63 are also provided on the bracket 61; this arrangement ensures that the push head 64 moves along the axial direction of the push rod 63 during the forward and retracting actions.

[0057] In some possible implementations, the sealing structure 12 includes a sealing box 121 installed outside the sealing cover 7 and arranged corresponding to the push rod 63, and a sealing filler 122 arranged in the sealing box 121 and located between the sealing box 121 and the push rod 63;

[0058] Preferably, the sealing filler 122 is ceramic fiber felt. The setting of the sealing structure 12 can effectively realize the sealing cooperation between the sealing cover 7 and the push rod 63, and can also realize the sliding cooperation between the push rod 63 and the sealing cover 7, thereby avoiding the push rod 63 passing through the sealing cover 7 to form a gap, causing air leakage, and causing external air to enter the combustion chamber 1; at the same time, it further enhances the ability of alternative fuels to achieve full combustion, thereby effectively realizing the use of this device in conjunction with a cement kiln that uses full oxygen combustion; avoiding outside air from entering the combustion chamber 1 to reduce the oxygen concentration required by the cement kiln during full oxygen combustion.

[0059] In some possible embodiments, there are multiple groups of push heads 64 in each group of the pushing devices 6, and they are respectively connected to the push rods 63; the multiple groups of push heads 64 are arranged at equal intervals along the vertical direction; the push heads 64 in all the pushing devices 6 will form a stepped structure that is compatible with the stepped structure formed by the receiving platform.

[0060] In some possible implementations, an ash discharge port 9 is provided at the bottom of the sealing cover 7 and below the stepped material bed 4, and an air lock valve is provided on the ash discharge port 9;

[0061] Furthermore, the sealing cover 7 is bucket-shaped, and the ash discharge port 9 is also bucket-shaped, so that the substitute material leaking out of the gap formed by the push rod 63 and the hole will enter the ash discharge port 9 for collection, so that the whole device will not leak.

[0062] In some possible embodiments, the feeding port is located above the stepped material bed 4, and a spiral air-locking feeding device 3 is provided on the feeding port; the hot air inlet 2, the raw material inlet 10, and the burner 5 are all located above the stepped material bed 4 and at one end of the stepped material bed 4 close to the feeding port.

[0063] In some possible implementations, the top 101 of the combustion chamber 1 is an arc-shaped structure, which can effectively avoid airflow dead zones and make the furnace temperature uniform and stable. One or more raw meal inlets 10 are symmetrically arranged on the side wall of the combustion chamber 1, which are used to introduce low-temperature raw meal when necessary to cool the combustion chamber 1 and avoid excessive combustion temperature;

[0064] Refractory castables 102 are provided on the top 101 and inside the side walls of the entire combustion chamber 1 to protect the shell of the combustion chamber 1 from being damaged by high temperature.

[0065] A combustion method for an alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to the above, specifically comprising the following steps:

[0066] The alternative fuel is fed into the combustion chamber 1 through the feed port and spread on the stepped material bed 4. The hot air inlet 2 introduces the heat source and combustion-supporting gas from the tertiary air of the cement kiln system to heat and burn the alternative fuel.

[0067] During the combustion process of the alternative fuel, the alternative fuel is continuously pushed by the pushing device 6 and turned and transported downward along the stepped material bed 4, and the fuel is provided into the combustion chamber 1 through the burner 5 or the raw meal is provided into the combustion chamber 1 through the raw meal inlet 10 to adjust the temperature in the combustion chamber 1, so as to achieve full combustion of the alternative fuel;

[0068] After the alternative fuel is fully burned, the ash falls from the discharge port 8 of the combustion chamber 1 into the decomposition furnace 11 connected to the combustion chamber 1 as an admixture, thereby completing the treatment of the alternative fuel;

[0069] The alternative fuel dropped during the turning process of the alternative fuel will be collected in the ash discharge port 9 .

[0070] Furthermore, a temperature sensor for monitoring the combustion temperature is provided on the combustion chamber 1; the temperature sensor can be used to monitor the combustion temperature in real time, thereby achieving more accurate control of the combustion temperature;

[0071] In some possible implementations, during the combustion of the alternative fuel, when the temperature of the combustion chamber 1 is monitored to be lower than 850° C., the fuel is injected into the combustion chamber 1 through the burner 5 to increase the temperature of the combustion chamber 1 ;

[0072] During the combustion of the alternative fuel, when the temperature of the combustion chamber 1 is monitored to be higher than 1100° C., low-temperature raw meal enters the combustion chamber 1 from the raw meal inlet 10 to cool the combustion chamber 1 .

[0073] The present invention can be applied to a cement kiln system to burn alternative fuels, fully utilize the calorific value of the alternative fuels, reduce the amount of raw coal used in the cement production process, and perform harmless treatment on the alternative fuels.

[0074] The present invention can prevent external air from entering the kiln system, and does not affect the thermal balance stability of the firing system; it can prevent the leakage of alternative fuels during the processing process, and there is no secondary pollution; through the cooperation of the pushing device 6 and the stepped material bed 4, the alternative fuel can be turned over many times during the incineration process, and the incineration temperature of the alternative fuel can be effectively controlled to ensure full combustion and avoid secondary pollution caused by the generation of harmful derivatives. The device has a simple structure, convenient process layout, easy operation, and strong practicality.

[0075] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A pre-combustion furnace for alternative fuels with controllable combustion atmosphere and temperature, characterized in that: It includes a combustion chamber provided with a feeding port and a hot air inlet, a sealing cover installed at the bottom of the combustion chamber and cooperating with the combustion chamber to form a chamber, a stepped material bed installed in the chamber and in a stepped shape, a pushing device installed on the outside of the sealing cover and having one end extending into the chamber to flip and push the alternative fuel on the stepped material bed, a burner arranged on the combustion chamber and used for fuel injection, and a raw material inlet for conveying raw material into the combustion chamber; the injection direction of the fuel is the same as the movement direction of the alternative fuel; and the combustion chamber is connected to a decomposition furnace.

2. The alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to claim 1, characterized in that: The pushing device includes a pushing head that slides with the stepped material bed, a pushing rod with one end connected to the pushing head and the other end located outside the sealing cover, and a driving device connected to the end of the pushing rod away from the pushing head and used to control the pushing rod to make linear reciprocating motion along its axial direction; a sealing structure that seals with the pushing rod and allows the pushing rod to pass through is provided on the sealing cover.

3. The alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to claim 2, characterized in that: The sealing structure comprises a sealing box which is installed outside the sealing cover and arranged corresponding to the push rod, and a sealing filler which is arranged in the sealing box and located between the sealing box and the push rod.

4. The alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to claim 2, characterized in that: The stepped material distribution bed is inclined so that the angle formed by the stepped material distribution bed and the horizontal plane is 20-40°; The stepped material distribution bed includes a plurality of receiving platforms arranged in sequence from top to bottom and located in the chamber, and a connecting plate arranged between two adjacent receiving platforms; the pusher head is located between two adjacent receiving platforms; and a hole for the pusher head to pass through is arranged on the connecting plate.

5. The alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to claim 2, characterized in that: There are multiple groups of push heads in each group of the pushing device, and they are respectively connected to the push rods; the multiple groups of push heads are arranged at equal intervals along the vertical direction.

6. The alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to claim 2, characterized in that: An ash discharge port is arranged at the bottom of the sealing cover and below the stepped material bed, and an air lock valve is arranged on the ash discharge port.

7. An alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to any one of claims 1 to 6, characterized in that: The feeding port is located above the stepped material bed, and a spiral air-locking feeding device is arranged on the feeding port; the hot air inlet, the raw material access port, and the burner are all located above the stepped material bed and at one end of the stepped material bed close to the feeding port.

8. The alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to claim 7, characterized in that: The top of the combustion chamber is an arc-shaped structure, and refractory castables are arranged in the side walls of the combustion chamber.

9. A combustion method for an alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to any one of claims 1 to 8, characterized in that: The specific steps include: The alternative fuel is fed into the combustion chamber from the feed port and spread onto the stepped material bed. The hot air inlet introduces heat source and combustion-supporting gas from the tertiary air of the cement kiln system to heat and burn the alternative fuel. During the combustion process of the alternative fuel, the alternative fuel is continuously pushed by the pushing device to be turned and transported downward along the stepped material bed, and the temperature in the combustion chamber is adjusted by providing fuel into the combustion chamber through the burner or providing raw meal into the combustion chamber through the raw meal inlet, so as to achieve full combustion of the alternative fuel; After the alternative fuel is fully burned, the ash falls from the discharge port of the combustion chamber into the decomposition furnace connected to the combustion chamber as an admixture, completing the treatment of the alternative fuel; The alternative fuel dropped during the alternative fuel turning process will be collected in the ash discharge port.

10. A combustion method for an alternative fuel pre-combustion furnace with controllable combustion atmosphere and temperature according to claim 9, characterized in that: During the combustion of alternative fuels, when the monitored combustion chamber temperature is below 850°C, fuel is injected into the combustion chamber through the burner to increase the combustion chamber temperature; During the combustion of alternative fuels, when the monitored combustion chamber temperature is higher than 1100°C, low-temperature raw meal enters the combustion chamber from the raw meal inlet to cool the combustion chamber.

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