Substitute fuel pre-combustion furnace

Abstract

The utility model discloses an alternative fuel pre-combustion furnace, which relates to the technical field of pre-combustion furnaces and comprises a furnace body communicated with a decomposing furnace, the furnace body is provided with a feeding channel, an air guide pipe and a material guide pipe, the inner wall of the furnace body is provided with a step, the step is provided with an air cannon, an inclined plane is arranged between the step and the decomposing furnace, and the material guide pipe is provided with a material guide pipe. A moving assembly for pushing fuel is arranged on the inclined plane, and an oxygen-enriched nozzle communicated with an oxygen supply system is arranged on the furnace body. Through the moving assembly arranged on the inclined plane, the pre-combusted alternative fuel is stably moved into the decomposing furnace after being fully combusted, local high-temperature points are effectively prevented from being generated in the pre-combustion furnace, and therefore the service life of the furnace body is prolonged, and the practicability is higher.

Description

Technical Field

[0001] This utility model relates to the field of pre-combustion furnace technology, and in particular to an alternative fuel pre-combustion furnace. Background Technology

[0002] Driven by the strategic goal of "carbon peaking and carbon neutrality," the large-scale use of energy-containing solid wastes such as waste-derived materials, tire-derived materials, and biomass as alternative fuels has become the most pressing carbon reduction technology in the cement industry. However, alternative fuels are characterized by high moisture content, low calorific value, large particle size, slow combustion speed, and high oxygen demand, making them prone to incomplete combustion in the decomposition furnace. This not only causes significant heat loss but also reduces the efficiency and quality of cement production. Therefore, a pre-combustion furnace is needed outside the decomposition furnace for drying and pre-combustion, and a certain amount of oxygen must be introduced to promote complete combustion of the alternative fuel in both the pre-combustion furnace and the decomposition furnace, thereby improving the thermal efficiency of the alternative fuel. Currently, the cement industry uses alternative fuel pre-combustion furnaces in various forms, including stepped furnaces, hot plate furnaces, and rotary kilns. Among these, stepped furnaces require the introduction of raw materials to control the furnace temperature, resulting in severe internal coking; hot plate furnaces are expensive and have low operating efficiency; and rotary kilns are expensive, and the internal refractory bricks are prone to abrasion and burn-off. The application of these common alternative fuel pre-combustion furnaces in actual industrial production faces numerous difficulties.

[0003] For example, announcement number CN220322029U was published on January 9, 2024. The disclosed alternative fuel oxygen-enriched pre-combustion furnace has a feed inlet connected to one side of the furnace body, an air inlet connected to the top of the furnace body, and a discharge outlet connected to the other side of the furnace body, which is interconnected with the interior of the decomposition furnace. The furnace body has a furnace bed with several sequentially arranged pre-combustion grate plates, the height of which decreases sequentially from the feed inlet to the discharge outlet. The feed inlet is connected to several feeding mechanisms, including a compressed air system and nozzles / pulse valves. The number of nozzles / pulse valves is the same as the number of pre-combustion grate plates, and each nozzle / pulse valve is embedded in the lower part of a corresponding pre-combustion grate plate. In use, the alternative fuel in the aforementioned pre-combustion furnace tends to accumulate at the obliquely arranged discharge outlet, causing localized high-temperature points after combustion, which can easily damage the pre-combustion furnace and reduce its service life. Summary of the Invention

[0004] The purpose of this invention is to provide a pre-combustion furnace for alternative fuels with a longer service life. This invention utilizes a movable component mounted on an inclined surface to ensure the pre-combustioned alternative fuel is fully burned and then stably moved into the decomposition furnace, effectively preventing localized high-temperature points within the pre-combustion furnace, thereby increasing the furnace's service life and enhancing its practicality.

[0005] To achieve the above objectives, the technical solution adopted by this utility model to solve its technical problem is: a pre-combustion furnace for alternative fuels, including a furnace body connected to a decomposition furnace, wherein the furnace body is provided with a feeding channel, an induced draft pipe and a feed pipe, a step is provided on the inner wall of the furnace body, an air cannon is provided on the step, an inclined surface is provided between the step and the decomposition furnace, a moving component for pushing fuel is provided on the inclined surface, and an oxygen-enriching nozzle connected to an oxygen supply system is provided on the furnace body.

[0006] The moving component includes a hydraulic cylinder disposed outside the furnace body. A second fixed seat is provided on the outer wall of the furnace body. The second fixed seat is connected to the hydraulic cylinder. A connecting column is provided on the piston of the hydraulic cylinder. The connecting column extends into the furnace body. A push plate connected to the connecting column is provided inside the furnace body.

[0007] The air cannon is equipped with a connecting pipe at its outlet, which extends to the steps of the furnace body.

[0008] The feeding channel is equipped with a rotating shaft, on which a spiral reamer is mounted. A first fixed seat is provided on the outer wall of the furnace body, and a motor is mounted on the first fixed seat. One end of the rotating shaft extends out of the furnace body, and the other end of the rotating shaft is connected to the power output shaft of the motor.

[0009] The oxygen-enriched nozzle is installed on the side wall of the furnace body, and the oxygen-enriched nozzle is located between the stepped furnace and the decomposition furnace.

[0010] The furnace body is equipped with thermocouples.

[0011] The oxygen-enriched nozzle includes a connecting cylinder that communicates with the oxygen supply system. The connecting cylinder is provided with a duckbill seat, the duckbill seat is provided with a discharge seat, the discharge seat is provided with a spray channel, and the duckbill seat is provided with a connecting channel. The connecting channel and the spray channel are connected, and the diameter of the spray channel increases uniformly from the inside to the outside.

[0012] The spacing between adjacent ejection channels increases uniformly from the middle position to both sides.

[0013] The beneficial effects of this utility model are:

[0014] The alternative fuel, after being pre-combusted, is stably moved into the decomposition furnace after being fully combusted by the moving components set on the inclined surface. This effectively avoids the generation of local high-temperature points in the pre-combustion furnace, thereby increasing the service life of the furnace body and making it more practical.

[0015] A thermocouple is installed above the oxygen-enriched gas nozzle to measure the temperature of the flue gas entering the furnace. When the temperature exceeds 1050℃, the air cannon injection speed and the hydraulic push rod pushing speed are increased to shorten the time that the alternative fuel stays in the pre-combustion furnace and avoid local high temperature in the pre-combustion furnace caused by over-burning of the alternative fuel.

[0016] The motor's operation causes the shaft to rotate, which in turn causes the spiral cutter to rotate, thereby rotating and pushing the fuel entering the feed channel. This ensures that the alternative fuel is evenly delivered to the pre-combustion furnace system and provides an airlock effect, preventing cold air from entering the system along with the alternative fuel and affecting the thermal regime of the pre-combustion furnace system. This ensures the stable drying and pre-combustion of the alternative fuel. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the alternative fuel pre-combustion furnace of this utility model.

[0018] Figure 2 for Figure 1 A schematic diagram of the oxygen-enriched nozzle structure of an alternative fuel pre-combustion furnace.

[0019] Figure 3 for Figure 2 Side view.

[0020] Figure 4 for Figure 2 A partial structural schematic diagram of the cross-sectional view.

[0021] In the attached diagram: 1-Decomposition furnace, 2-Induced draft pipe, 3-Furnace body, 4-Feeding channel, 5-Feeding pipe, 6-Rotating shaft, 7-Spiral reamer, 8-Motor, 9-First fixed seat, 10-Step, 11-Air cannon, 12-Thermocouple, 13-Connecting pipe, 14-Hydraulic cylinder, 15-Connecting column, 16-Push plate, 17-Second fixed seat, 18-Oxygen-enriched nozzle, 1801-Connecting cylinder, 1802-Duckbill seat, 1803-Discharge seat, 1804-Spraying channel, 1805-Connecting channel. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0023] The specific implementation of this utility model will be described in detail below with reference to specific embodiments.

[0024] like Figure 1As shown, the alternative fuel pre-combustion furnace includes a furnace body 3 connected to a decomposition furnace 1. The furnace body 3 is provided with a feeding channel 4, an induced draft pipe 2, and a feed pipe 5. The induced draft pipe 2 introduces high-temperature tertiary air for drying. The alternative fuel enters the furnace body 3 through the feed pipe 5. The inner wall of the furnace body 3 is provided with steps 10, and air cannons 11 are provided on the steps 10. In this embodiment, each step 10 is provided with two air cannons 11. An inclined surface is also provided between the steps 10 and the decomposition furnace 1. The inclined surface facilitates the pre-combustion of the dried alternative fuel on the inclined surface. A moving component is provided on the inclined surface to push the fuel, thereby ensuring that the pre-combustioned alternative fuel enters the decomposition furnace 1 stably for combustion and preventing the alternative fuel from sticking on the inclined surface. The furnace body 3 is provided with an oxygen-enriched nozzle 18 connected to an oxygen supply system. The oxygen supply system includes a gas tank containing oxygen-enriched gas, and the gas tank is connected to the oxygen-enriched nozzle 18 through an oxygen supply pipe.

[0025] Specifically, the furnace body 3 of the alternative fuel pre-combustion furnace is 2-3m wide and 6-8m long, with 4-6 steps at the front end and a slope angle of 30-50° at the rear end. In this embodiment, the width is 2.5m, the length is 7m, there are four steps, and the slope angle is 35°.

[0026] The refractory material of the inner wall of the pre-combustion furnace body 3 is made of microcrystalline material to prevent coking in the furnace step 10. The material of the oxygen enrichment nozzle 18 is made of high temperature and wear-resistant ceramic to prevent high temperature burn-off and mechanical abrasion.

[0027] The amount of tertiary air introduced is controlled to have an excess air coefficient of 0.3-0.5 in the pre-combustion furnace. The alternative fuel is pyrolyzed in the pre-combustion furnace to produce pyrolysis gas which enters the decomposition furnace. This prevents overburning in the pre-combustion furnace, which can cause local high temperatures that lead to crusting or burn-off of refractory materials. The oxygen-enriched gas concentration sprayed from the oxygen-enriched nozzle 18 is ≥80%, and the spraying pressure is set to 20-40 kPa.

[0028] In use, the material enters the feed channel 4 of the furnace body 3 through the feed pipe 5, and the tertiary air enters the furnace body 3 through the air duct 2. After entering the furnace body 3, the material undergoes full heat exchange with the high-temperature gas, rapidly heating up and drying, effectively improving combustion efficiency. After the alternative fuel enters the furnace body 3, it stays at each step 10, extending the reaction time of the alternative fuel in the furnace body 3. Then, the alternative fuel is sprayed into the next step by the periodically operating air cannon 11 until the alternative fuel falls on the inclined surface of the furnace body 3. The oxygen supply system supplies oxygen-enriched gas injected by the oxygen-enriched nozzle 18, which in turn creates a local oxygen-enriched environment on the inclined surface and generates airflow disturbance, accelerating the combustion speed of the alternative fuel. After the alternative fuel begins to burn on the inclined surface, the moving component works to quickly push the fuel into the decomposition furnace 1, where it is fully burned and releases heat, effectively avoiding the generation of local high-temperature points in the furnace body 3, thus ensuring stable pre-combustion of the alternative fuel and making it more practical.

[0029] The moving component includes a hydraulic cylinder 14 disposed outside the furnace body 3. A second fixed seat 17 is provided on the outer wall of the furnace body 3. The second fixed seat 17 is connected to the hydraulic cylinder 14. A connecting column 15 is provided on the piston of the hydraulic cylinder 14. The connecting column 15 extends into the furnace body 3. A push plate 16 connected to the connecting column 15 is provided inside the furnace body 3. When the hydraulic cylinder 14 works, the piston moves, which drives the connecting column 15 to move. In turn, the connecting column 15 drives the push plate 16 to move inside the furnace body 3. As a result, the pre-burned alternative fuel is moved from the furnace body 3 to the decomposition furnace 1 by the push plate 16, preventing the alternative fuel from accumulating on the inclined surface of the furnace body 3. In this embodiment, the second fixed seat 17 is welded to the outer wall of the furnace body 3. The second fixed seat 17 is connected to the hydraulic cylinder 14 by bolts.

[0030] The air cannon 11 has a connecting pipe 13 at its outlet end, which extends to the steps 10 of the furnace body 3. The gas generated by the air cannon 11 enters the furnace body 3 through the connecting pipe. The gas sprays the fuel on the steps 10 onto the next step 10, thereby ensuring the stable movement of the fuel on the steps 10. Specifically, each step 10 is designed with two air cannons 11, with the pressure set at 0.4-0.8 MPa, the interval between each air cannon set at 5 seconds, and the cycle time at 100 seconds. Specifically, a platform is provided on the outside of the furnace body 3, and the air cannons 11 are placed on the platform to ensure the precise fixation of the air cannons 11 on the outside of the furnace body 3.

[0031] A rotating shaft 6 is provided inside the feeding channel 4, and a spiral reamer 7 is provided on the rotating shaft 6. A first fixed seat 9 is provided on the outer wall of the furnace body 3, and a motor 8 is provided on the first fixed seat 9. One end of the rotating shaft 6 extends outside the furnace body 3, and the end of the rotating shaft 6 is connected to the power output shaft of the motor 8. When the motor 8 works, the rotating shaft 6 rotates, which in turn causes the spiral reamer 7 to rotate, thereby rotating and pushing the fuel entering the feeding channel 4. This achieves uniform delivery of the alternative fuel to the pre-combustion furnace system and provides an airlock effect, preventing cold air from entering the system along with the alternative fuel and affecting the thermal regime of the pre-combustion furnace system. This ensures the stable drying and pre-combustion of the alternative fuel. In this embodiment, the first fixed seat 9 is welded to the outer wall of the furnace body 3, and the first fixed seat 9 is connected to the motor 8 by bolts. The power output shaft of the motor 8 is connected to the rotating shaft 6 by a coupling.

[0032] The oxygen-enriched nozzle 18 is installed on the side wall of the furnace body 3 and between the step 10 and the decomposition furnace 1. This ensures that the oxygen-enriched gas discharged from the oxygen-enriched nozzle 18 can stably contact the fuel on the inclined surface, forming a local oxygen-enriched environment and strengthening the airflow disturbance in the reaction zone, thereby promoting the combustion of alternative fuels.

[0033] Thermocouple 12 is installed on the furnace body 3 to measure the temperature of the flue gas entering the furnace. When the temperature exceeds 1050℃, the blowing speed of air cannon 11 and the pushing speed of hydraulic cylinder 14 are increased to shorten the time that the alternative fuel stays in the pre-combustion furnace and avoid the alternative fuel from overburning and causing local high temperature in the pre-combustion furnace.

[0034] Reference Figure 2-4 The oxygen-enriched nozzle 18 includes a connecting cylinder 1801 connected to an oxygen supply system. A duckbill seat 1802 is provided on the connecting cylinder 1801, and a discharge seat 1803 is provided on the duckbill seat 1802. A spray channel 1804 is provided inside the discharge seat 1803, and a connecting channel 1805 is provided inside the duckbill seat 1802. The connecting channel 1805 and the spray channel 1804 are connected. The diameter of the spray channel 1804 increases uniformly from the inside to the outside. Oxygen-enriched gas enters the connecting cylinder 1801 through the oxygen supply system, and then passes through the connecting channel 1805 of the duckbill seat 1802. The oxygen is discharged through the outlet channel 1804 of the channel 1805 and the outlet seat 1803, thereby realizing the oxygen supply of the furnace body 3. Specifically, the duckbill seat 1802 is shaped like a trumpet, and the diameter of the outlet channel 1804 increases uniformly from the inside to the outside, so that the oxygen-enriched gas gradually decreases in speed and gradually increases in pressure during the flow process. The gas can flow out of the nozzle more smoothly, reducing turbulence and pressure fluctuations during gas injection and expanding the range of gas injection. At the same time, the appropriate reduction in the speed of the oxygen-enriched gas is conducive to better mixing with the fuel and promoting stable and complete combustion.

[0035] Reference Figure 4 The spacing between adjacent ejection channels 1804 increases uniformly from the middle to both sides. The ejection channels 1804 in the middle part of the discharge seat 1803 are more densely distributed, while the ejection channels 1804 on both sides are relatively sparse. The central area has more sufficient contact with oxygen, thus improving the utilization efficiency of oxygen.

[0036] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A substitute fuel pre-combustion furnace comprising a furnace body (3) in communication with a decomposition furnace (1), said furnace body (3) being provided with a feed channel (4), an air duct (2) and a material duct (5), characterized in that, The inner wall of the furnace body (3) is provided with a ladder (10), the ladder (10) is provided with an air cannon (11), and a slope is further arranged between the ladder (10) and the decomposition furnace (1), the slope is provided with a moving assembly for pushing fuel, and the furnace body (3) is provided with an oxygen-rich nozzle (18) connected with an oxygen supply system.

2. The alternative fuel precombustion furnace according to claim 1, characterized in that, The moving assembly comprises a hydraulic cylinder (14) arranged outside the furnace body (3), a second fixed seat (17) is arranged on the outer wall of the furnace body (3), the second fixed seat (17) is connected with the hydraulic cylinder (14), a connecting column (15) is arranged on the piston of the hydraulic cylinder (14), the connecting column (15) extends into the furnace body (3), and a push plate (16) connected with the connecting column (15) is arranged in the furnace body (3).

3. The alternative fuel precombustion furnace according to claim 1, characterized in that, The air cannon (11) is provided with a connecting pipe (13) at the gas outlet end, and the connecting pipe extends to the ladder (10) of the furnace body (3).

4. A replacement fuel precombustion furnace according to any one of claims 1-3, characterized in that, The feeding channel (4) is provided with a rotating shaft (6), the rotating shaft (6) is provided with a spiral reamer (7), a first fixed seat (9) is arranged on the outer wall of the furnace body (3), a motor (8) is arranged on the first fixed seat (9), one end of the rotating shaft (6) extends out of the furnace body (3), and the end of the rotating shaft (6) is connected with the power output shaft of the motor (8).

5. The alternative fuel precombustion furnace according to claim 4, characterized in that, The oxygen-rich nozzle (18) is arranged on the side wall of the furnace body (3), and the oxygen-rich nozzle (18) is arranged between the ladder (10) and the decomposition furnace (1).

6. The alternative fuel precombustion furnace according to claim 5, characterized in that, The furnace body (3) is provided with a thermocouple (12).

7. The alternative fuel precombustion furnace according to claim 5, characterized in that, The oxygen-rich nozzle (18) comprises a connecting cylinder (1801) connected with the oxygen supply system, a duckbill seat (1802) is arranged on the connecting cylinder (1801), a discharge seat (1803) is arranged on the duckbill seat (1802), an ejection channel (1804) is arranged in the discharge seat (1803), a connecting channel (1805) is arranged in the duckbill seat (1802), the connecting channel (1805) and the ejection channel (1804) are communicated, and the diameter of the ejection channel (1804) uniformly increases from inside to outside.

8. The alternative fuel precombustion furnace according to claim 7, characterized in that, The distance between adjacent ejection channels (1804) uniformly increases from the middle position to both sides.

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