A combined gasification and incineration disposal system suitable for industrial solid waste

Abstract

This invention provides a combined gasification incineration system suitable for industrial solid waste. Industrial solid waste enters the rotary kiln via a feed device, undergoing drying and pyrolysis while rotating. The pyrolysis residue falls from the rotary kiln outlet onto a mechanical grate furnace, while some of the pyrolysis gas enters the secondary combustion chamber. The pyrolysis residue is fully combusted in the mechanical grate furnace, and the flue gas enters the secondary combustion chamber for further combustion. The burnt slag is then discharged by a slag removal system. Simultaneously, the gasification incineration air system and burners are respectively arranged in the rotary kiln, mechanical grate furnace, and secondary combustion chamber. By decomposing the incineration process—the rotary kiln performs pyrolysis and gasification, the mechanical grate furnace fully incinerates the solid waste, and the secondary combustion chamber fully incinerates the flue gas and pyrolysis gas—the incineration process can be precisely controlled by adjusting the subsystem states. Furthermore, by reducing the size of the rotary kiln and minimizing its footprint, the system ensures that drying and pyrolysis gasification occur within the rotary kiln, while transferring the main incineration process to the mechanical grate furnace, achieving efficient and complete incineration.

Description

Technical Field

[0001] This invention belongs to the field of incineration technology, and specifically relates to a combined gasification incineration system suitable for industrial solid waste. Background Technology

[0002] my country has a huge amount of industrial solid waste that requires safe disposal, and incineration is one of the important methods for handling industrial solid waste. Common incineration equipment includes mechanical grate furnaces, fluidized bed incinerators, rotary kilns, or combinations of the above types.

[0003] A grate furnace is a mechanical device used for incinerating municipal solid waste, consisting of grate blocks and an air distribution system. Waste is distributed on top of the grate blocks, and the movement of the grate blocks propels the waste forward, causing combustion. Mechanical grate furnaces are adaptable to various materials, provide complete combustion, and can achieve large-scale incineration, making them suitable for treating municipal solid waste. However, for industrial solid waste, due to its more complex composition and higher calorific value compared to municipal solid waste, the grate bars need to withstand higher temperatures, thus limiting its application. Fluidized bed incinerators have a simple structure, high heat and mass transfer efficiency, and complete combustion. However, to ensure the fluidization state within the fluidized bed, strict requirements are placed on the physicochemical properties of the feed. They are generally used for relatively simple materials, and the materials need to be pre-treated to achieve uniform size and not exceed 100mm. Therefore, the applicability of fluidized bed incinerators is limited. Meanwhile, fluidized bed incinerators have a high dust content in their flue gas, increasing the difficulty of flue gas treatment. Rotary kilns, on the other hand, are highly adaptable to materials and can effectively process wastes of various physical states, making them suitable for general industrial solid wastes and hazardous wastes with complex compositions and high calorific values. However, due to their structural characteristics, rotary kilns are typically very long, and the primary air is unevenly distributed within the kiln, resulting in the combustion zone occupying only a small portion of the entire incinerator, leading to incomplete material combustion. Most of the material is heated by gases generated during the fueling process and heat transferred from the kiln walls. This results in rotary kilns having a large footprint, low combustion efficiency, and high requirements for the combustion load of the subsequent secondary combustion chamber.

[0004] In summary, all three processes mentioned above have numerous drawbacks when used alone for incinerating industrial solid waste. Currently, various technologies are applied in the selection of incineration technologies for general industrial solid waste, but each has its own limitations. There is no single, universally applicable incineration technology that can economically, efficiently, and fully incinerate general industrial solid waste. Therefore, there is an urgent need to develop a new incineration method that overcomes the shortcomings of various furnace types and is suitable for general industrial solid waste. Summary of the Invention

[0005] The purpose of this invention is to provide a combined gasification incineration system suitable for industrial solid waste, which reduces the footprint and improves combustion efficiency.

[0006] To solve the above-mentioned technical problems, the present invention provides a combined gasification incineration treatment system suitable for industrial solid waste, including a rotary kiln feeding system, a rotary kiln, a mechanical grate furnace, a secondary combustion chamber, a burner, a slag discharge system, and an air system;

[0007] The discharge port of the rotary kiln feeding system is connected to the feed port of the rotary kiln, the discharge port of the rotary kiln is connected to the feed port of the mechanical grate furnace, the pyrolysis gas outlet of the mechanical grate furnace is connected to the inlet of the secondary combustion chamber, and the pyrolysis residue outlet of the mechanical grate furnace is connected to the inlet of the slag discharge system.

[0008] The burners include a rotary kiln burner disposed in the rotary kiln, a grate furnace burner disposed in the mechanical grate furnace, and a secondary combustion chamber burner disposed in the secondary combustion chamber;

[0009] The air system includes a primary air system for supplying air to the rotary kiln, a grate air system for supplying air to the mechanical grate furnace, and a secondary air system for supplying air to the secondary combustion chamber.

[0010] Optionally, in the above-mentioned combined gasification incineration treatment system applicable to industrial solid waste, the rotary kiln has a length-to-diameter ratio of 2-2.5.

[0011] Optionally, in the above-mentioned combined gasification incineration treatment system for industrial solid waste, the rotary kiln feeding system includes a feed hopper, a chute, a double-layer flap valve, a pushing device, and a hydraulic station. The feed hopper is connected to the kiln head of the rotary kiln through the chute. The pushing device is used to push the industrial solid waste in the chute. The chute is equipped with a double-layer flap valve, which opens and closes alternately to ensure that one valve is closed at any given time.

[0012] Optionally, in the above-mentioned combined gasification incineration system for industrial solid waste, the rotary kiln includes a kiln head, a kiln tail, a kiln body, a trolley, a transmission mechanism, a reducer, gears, and a sealing device. The kiln head is higher than the kiln tail, and the kiln head is equipped with the rotary kiln burner and the rotary kiln primary air inlet.

[0013] Optionally, in the above-mentioned combined gasification incineration treatment system suitable for industrial solid waste, a movable baffle for adjusting the amount of pyrolysis gas is provided at the connection between the kiln tail of the rotary kiln and the feed inlet of the mechanical grate furnace.

[0014] Optionally, in the above-mentioned combined gasification incineration treatment system applicable to industrial solid waste, the pyrolysis gas outlet of the rotary kiln and the secondary combustion chamber are connected by a pyrolysis gas discharge device.

[0015] The pyrolysis gas discharge device includes multiple discharge pipes and a manifold. The discharge pipes pass through the kiln body, one end of the manifold is connected to the secondary combustion chamber, and the other end of the manifold extends to the outside of the kiln body and is connected to the multiple discharge pipes through a mechanical seal device.

[0016] Optionally, in the above-mentioned combined gasification incineration system for industrial solid waste, the mechanical grate furnace is a forward-pushing reciprocating grate, including a movable grate and a fixed grate.

[0017] Optionally, in the above-mentioned combined gasification incineration system for industrial solid waste, the secondary combustion chamber includes a medium-temperature zone and a high-temperature zone. The front of the medium-temperature zone is connected to the kiln tail of the rotary kiln, the grate furnace burner is installed at the rear arch of the medium-temperature zone, and the top of the medium-temperature zone is connected to the high-temperature zone.

[0018] Optionally, in the above-mentioned combined gasification incineration system for industrial solid waste, the intermediate temperature zone is a horizontal rectangular box, and the mechanical grate furnace is installed at the bottom of the horizontal rectangular box.

[0019] Optionally, in the above-mentioned combined gasification incineration treatment system suitable for industrial solid waste, water-cooled walls are provided on both sides and the top of the front end of the intermediate temperature zone.

[0020] Optionally, in the above-mentioned combined gasification incineration system for industrial solid waste, the connection between the medium-temperature zone and the high-temperature zone is designed with a narrowing and a flame deflector.

[0021] Optionally, in the above-mentioned combined gasification incineration treatment system applicable to industrial solid waste, the high-temperature zone is a vertical high-cube box, and the vertical high-cube box houses the secondary combustion chamber burner and the secondary air inlet of the secondary combustion chamber.

[0022] The combined gasification incineration system for industrial solid waste provided by this invention has the following beneficial effects:

[0023] Industrial solid waste enters the rotary kiln through the feeding device, where it is dried and pyrolyzed while rotating. The pyrolysis residue falls onto the mechanical grate furnace through the kiln's outlet, where it is fully combusted. The flue gas then enters the secondary combustion chamber for further combustion, and the combusted slag is discharged through the slag removal system. Due to the baffles, a portion of the pyrolysis gas from the rotary kiln enters the grate furnace, while the remainder enters the high-temperature zone of the secondary combustion chamber. This ratio can be adjusted according to the baffle height. The gasification and incineration air system has three air inlets: primary air from the rotary kiln, grate air from the grate furnace, and secondary air from the secondary combustion chamber. The burners are also arranged in three locations: the rotary kiln burner, the grate furnace burner, and the secondary combustion chamber burner.

[0024] This scheme decomposes the incineration process into three stages. Pyrolysis gasification is controlled within the rotary kiln, while the complete incineration of solid waste is controlled on a mechanical grate furnace, with the flue gas and pyrolysis gas being fully incinerated in a secondary combustion chamber. By decomposing the incineration process and adjusting the state of each subsystem through control measures, the goal of precisely controlling the incineration process can be achieved. By reducing the length-to-diameter ratio of the rotary kiln and shortening its length, drying and pyrolysis gasification are ensured within the rotary kiln. This achieves two goals: firstly, reducing the amount of solid waste and the processing capacity of subsequent grates; secondly, the generated pyrolysis gas is more easily combusted in the secondary combustion chamber, reducing the incineration load in the secondary combustion chamber; and thirdly, eliminating the low-efficiency portion of the rotary kiln incineration and transferring the main incineration process to the mechanical grate furnace. The high incineration efficiency of the grate furnace is fully utilized, ensuring complete combustion of solid materials on the grate. This invention combines the advantages of each system, reducing the footprint and achieving efficient and complete incineration. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0026] Figure 1 This invention provides a process flow diagram of a combined gasification incineration treatment system for industrial solid waste.

[0027] Figure 2 This invention provides an equipment layout diagram for a combined gasification incineration treatment system suitable for industrial solid waste.

[0028] Figure 3 This invention provides a general layout diagram of the feeding system in a combined gasification incineration treatment system for industrial solid waste.

[0029] Figure 4 The present invention provides a general layout diagram of a rotary kiln suitable for a combined gasification incineration treatment system for industrial solid waste.

[0030] Figure 5 for Figure 4 Sectional view along direction AA;

[0031] Figure 6 for Figure 4 Sectional view along the CC direction;

[0032] Figure 7 This invention provides a general layout diagram of the mechanical grate and slag discharge system in a combined gasification incineration system for industrial solid waste.

[0033] Figure 8 This invention provides a general layout diagram of the secondary combustion chamber in a combined gasification incineration system for industrial solid waste.

[0034] In the image above:

[0035] 2-Rotary kiln feeding system; 2a-Hopper; 2b-Chutter; 2c-Double-layer flap valve; 2d-Pushing device; 2e-Hydraulic station;

[0036] 3-Rotary kiln; 3a-Kiln head; 3b-Kiln tail; 3c-Kiln body; 3d-Roller; 3e-Transmission mechanism; 3f-Reducer; 3g-Gear; 3h-Sealing device; 3i-Refractory material; 3j-Modible baffle; 3k-Pyrolysis gas discharge device; 3ka-Discharge pipe; 3kb-Manifold;

[0037] 4-Mechanical grate furnace; 4a-Moving grate; 4b-Fixed grate; 4c-Wind chamber; 4d-Grate bars;

[0038] 5-Secondary combustion chamber; 5a-Medium temperature zone; 5b-High temperature zone; 5c-Water-cooled wall; 5d-Emergency exhaust chimney; 5e-Flue gas outlet;

[0039] 6-Burner; 6a-Rotary kiln burner; 6b-Grate furnace burner; 6c-Secondary combustion chamber burner;

[0040] 7-Slag removal system; 7a-Slag hopper; 7b-Slag remover; 7c-Slag hopper below grate; 7d-Conveyor;

[0041] 8-Air system; 8a-Rotary kiln primary air inlet; 8b-Grate exhaust air inlet; 8c-Secondary air inlet of the secondary combustion chamber. Detailed Implementation

[0042] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0043] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0044] In the description of this invention, "multiple" means two or more. If "first" and "second" are mentioned, they are only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the order of the technical features indicated.

[0045] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0046] The core of this invention is to provide a combined gasification incineration system suitable for industrial solid waste, which can reduce the footprint and improve combustion efficiency.

[0047] To enable those skilled in the art to better understand the technical solutions provided by the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] Please refer to Figures 1-8 , Figure 1 This invention provides a process flow diagram of a combined gasification incineration treatment system for industrial solid waste. Figure 2 This invention provides an equipment layout diagram for a combined gasification incineration treatment system suitable for industrial solid waste. Figure 3 This invention provides a general layout diagram of the feeding system in a combined gasification incineration treatment system for industrial solid waste. Figure 4 The present invention provides a general layout diagram of a rotary kiln suitable for a combined gasification incineration treatment system for industrial solid waste. Figure 5 for Figure 4 Sectional view along direction AA; Figure 6 for Figure 4 Sectional view along the CC direction; Figure 7 This invention provides a general layout diagram of the mechanical grate and slag discharge system in a combined gasification incineration system for industrial solid waste. Figure 8 This invention provides a general layout diagram of the secondary combustion chamber in a combined gasification incineration system for industrial solid waste.

[0049] This invention provides a combined gasification incineration treatment system suitable for industrial solid waste, including a rotary kiln feeding system 2, a rotary kiln 3, a mechanical grate furnace 4, a secondary combustion chamber 5, a burner 6, a slag discharge system 7, and an air system 8.

[0050] The discharge port of the rotary kiln feeding system 2 is connected to the feed port of the rotary kiln 3, the discharge port of the rotary kiln 3 is connected to the feed port of the mechanical grate furnace 4, and the pyrolysis gas outlet of the mechanical grate furnace 4 is connected to the inlet of the secondary combustion chamber 5. A pyrolysis gas bypass pipe is added to the tail of the rotary kiln 3 to connect to the secondary combustion chamber 5. The pyrolysis residue outlet of the mechanical grate furnace 4 is connected to the inlet of the slag removal system 7.

[0051] The burner 6 includes a rotary kiln burner 6a installed in the rotary kiln 3, a grate furnace burner 6b installed in the mechanical grate furnace 4, and a secondary combustion chamber burner 6c installed in the secondary combustion chamber 5.

[0052] The air system 8 includes a primary air system for supplying air to the rotary kiln 3, a grate air system for supplying air to the mechanical grate furnace 4, and a secondary air system for supplying air to the secondary combustion chamber 5.

[0053] This invention provides a combined gasification incineration system suitable for industrial solid waste treatment. The process flow of the combined gasification incineration system is as follows: Figure 1 As shown, the system layout diagram is as follows: Figure 2 As shown, general industrial solid waste is stored in a waste pit after being crushed. The industrial solid waste enters the rotary kiln 3 through the rotary kiln feeding system 2. Inside the rotary kiln 3, it is dried and pyrolyzed while rotating. The pyrolysis residue falls from the discharge port (kiln tail 3b) of the rotary kiln 3 onto the mechanical grate furnace 4. The pyrolysis residue is fully burned on the mechanical grate furnace 4. Due to the baffle, part of the flue gas (pyrolysis gas) directly enters the secondary combustion chamber 5 for further full combustion, and part enters the grate furnace. The burnt slag is sent out by the slag discharge system 7.

[0054] The gasification and combustion air system 8 is divided into three air inlets: primary air from the rotary kiln, grate air from the grate furnace, and secondary air from the secondary combustion chamber. The burners are also divided into three locations: rotary kiln burner 6a, grate furnace burner 6b, and secondary combustion chamber burner 6c. By adjusting the air distribution ratio, pyrolysis occurs in the rotary kiln 3 at a temperature controlled between 550-650℃, pyrolysis residue is fully combusted on the mechanical grate furnace 4 at a temperature controlled around 900℃, and pyrolysis gas is fully combusted in the secondary combustion chamber 5 at a temperature above 1100℃.

[0055] This scheme decomposes the incineration process of industrial solid waste into three stages: anaerobic pyrolysis gasification, secondary incineration of pyrolysis products, and incineration of pyrolysis gas. The core equipment of this combined gasification incineration system consists of a rotary kiln 3, a mechanical grate furnace 4, and a secondary combustion chamber 5. The three stages of the incineration process are distributed across these three devices. Pyrolysis gasification is controlled within the rotary kiln 3, while the complete incineration of solid waste is controlled in the mechanical grate furnace 4, with the secondary combustion chamber 5 providing sufficient combustion of flue gas and pyrolysis gas. A pyrolysis gas discharge device 3k connects the rotary kiln and the secondary combustion chamber, regulating the heat load distribution within the three devices. By decomposing the incineration process and adjusting the state of each subsystem through control measures, precise control of the incineration process is achieved. By reducing the length-to-diameter ratio and shortening the length of the rotary kiln 3, drying and pyrolysis gasification are ensured within the rotary kiln 3. On the one hand, it reduces solid waste volume, decreasing the amount of waste processed by the subsequent grate; on the other hand, the generated pyrolysis gas is more easily combusted in the secondary combustion chamber 5, reducing the incineration load of the secondary combustion chamber 5; furthermore, it eliminates the low-efficiency portion of the rotary kiln 3, transferring the main incineration process to the mechanical grate furnace 4. It fully utilizes the high incineration efficiency of the grate, ensuring complete combustion of solid materials on the grate. This invention combines the advantages of various systems, reducing the footprint and achieving efficient and complete incineration.

[0056] In a specific embodiment, this invention is mainly used for solid waste disposal. Through the setup described in this invention, the length-to-diameter ratio of the rotary kiln 3 can be designed to be 2-2.5. Therefore, under the same processing capacity, the rotary kiln 3 in this invention is significantly shorter. A grate is added after the rotary kiln 3, and the rotary kiln 3 has a small length-to-diameter ratio and a short length. Drying and pyrolysis mainly occur within the rotary kiln 3. After the material volume is reduced, incineration is transferred to the grate. This fully utilizes the high combustion efficiency and low loss on ignition of the grate, resulting in more complete incineration.

[0057] In a specific embodiment, the hopper 2a of the rotary kiln feeding system 2 is connected to the kiln head 3a of the rotary kiln 3 via a chute 2b. This invention also includes a pusher device 2d for pushing industrial solid waste within the chute 2b.

[0058] The layout of the rotary kiln feeding system 2 is as follows: Figure 2 and Figure 3 As shown, the system mainly includes a feed hopper 2a, a chute 2b, a double-layer flap valve 2c, a pushing device 2d, and a hydraulic station 2e. Industrial solid waste, after being crushed, is stored in a waste pit. The material is fed into the feed hopper 2a of the rotary kiln 3 by a grab bucket, falls through the chute 2b to the pushing device 2d, and is then pushed into the kiln head 3a of the rotary kiln 3 by the pusher rod of the pushing device 2d. The chute 2b is equipped with a double-layer flap valve 2c, which opens and closes alternately to ensure that at any given time, one valve is closed, thus providing a sealing function.

[0059] Rotary kiln 3 Figure 2 and Figure 4As shown, the rotary kiln 3 includes a kiln head 3a, a kiln tail 3b, a kiln body 3c, rollers 3d (including front and rear rollers 3d), a transmission mechanism 3e, a reducer 3f, gears 3g, and a sealing device 3h (including front and rear seals). The rotary kiln 3 is installed at an angle, with the kiln head 3a higher than the kiln tail 3b. The kiln head 3a is connected to the chute 2b of the feeding device, and the kiln tail 3b extends into the medium-temperature zone 5a of the secondary combustion chamber 5, above the grate furnace. The inner wall of the kiln body 3c is covered with a refractory material layer 3i. The gears 3g include a gear cover, a large gear, and a small gear. Industrial solid waste enters through the kiln head 3a and moves towards the kiln tail 3b while rotating within the rotary kiln 3. A rotary kiln burner 6a and a rotary kiln primary air inlet 8a are installed at the kiln head 3a of the rotary kiln 3. Under the action of the burner and primary air, the solid waste is continuously tumbled, heated, dried, and pyrolyzed / gasified within the rotary kiln 3. The material gradually dries in the front section of rotary kiln 3 and begins pyrolysis in the middle and rear sections. In the 200d / t treatment scale project, the dimensions of rotary kiln 3 are Φ4.3×9.5m, which is much shorter than the 15-16m length of rotary kiln 3 in the same treatment scale. The purpose of shortening the length of rotary kiln 3 is to control the reaction process within it. By controlling the primary air intake to maintain it at 20% of the total air volume, the project ensures that the solid waste mainly undergoes pyrolysis and gasification reactions within rotary kiln 3, preventing incineration or only partially incinerating the solid waste. This shifts the main incineration process of solid waste to the grate path, enhancing incineration efficiency, and controls the outlet temperature of rotary kiln 3 to prevent overheating at the kiln tail 3b, extending the equipment's service life. The rotary kiln 3's rotation speed is frequency-controlled, allowing adjustment of the residence time of solid waste within the kiln to regulate the incineration process. With this configuration, the amount of combustion air in rotary kiln 3 is small, and the amount of flue gas generated by pyrolysis and gasification is small, which can greatly reduce the size of the equipment compared to a standalone rotary kiln 3.

[0060] Based on the above specific embodiments, a movable baffle 3j for adjusting the amount of pyrolysis gas is provided at the connection between the kiln tail 3b of the rotary kiln 3 and the feed inlet of the mechanical grate furnace 4. Industrial solid waste is dried and pyrolyzed while rotating inside the rotary kiln. The pyrolysis residue falls onto the mechanical grate furnace 4 through the gap between the kiln tail 3b of the rotary kiln 3 and the lower part of the movable baffle 3j. Due to the obstruction of the movable baffle 3j, some of the pyrolysis gas enters the secondary combustion chamber 5 through the pyrolysis gas discharge device 3k. Therefore, the amount of pyrolysis gas entering the mechanical grate furnace 4 can be limited by adjusting the movable baffle 3j. Part of the pyrolysis gas is sent from the kiln tail 3b of the rotary kiln 3 into the secondary combustion chamber 5 for incineration, aiming to regulate the heat load distribution between the mechanical grate furnace 4 and the secondary combustion chamber 5. This prevents overheating of the kiln tail and excessive heat load on the connecting wall between the kiln tail 3b and the mechanical grate furnace 4, thus preventing coking.

[0061] A vertical movable baffle 3j is installed at the kiln tail 3b of the rotary kiln 3. When the baffle is fully closed, the rotary kiln and the grate furnace are completely isolated. The opening degree of the baffle must ensure that the pyrolysis residue can fall completely onto the grate below. Specifically, the opening degree of the movable baffle 3j can be adjusted, thereby adjusting the distribution of pyrolysis gas entering the mechanical grate furnace 4 and the secondary combustion chamber 5. The rotary kiln 3 is equipped with an adjustment mechanism for controlling the opening degree of the movable baffle 3j. When the movable baffle 3j is hinged to the rotary kiln 3, the adjustment mechanism can be a locking mechanism to limit the rotation of the movable baffle 3j, or it can be a telescopic rod, a hydraulic cylinder, or other support adjustment mechanism.

[0062] It should be noted that the movable baffle 3j is adjustable. On the one hand, it is necessary to ensure that the pyrolysis residue can fall completely from the bottom of the rotary kiln 3. On the other hand, by adjusting the height of the movable baffle 3j, some pyrolysis gas is intercepted and discharged into the secondary combustion chamber 5 through the pyrolysis gas discharge device 3k.

[0063] Specifically, a pyrolysis gas outlet is provided above the kiln tail 3b of the rotary kiln 3, and the pyrolysis gas outlet is connected to the lower side of the secondary combustion chamber 5 through a pyrolysis gas discharge device 3k. For example... Figure 6 As shown, the pyrolysis gas discharge device 3k consists of six discharge pipes 3ka and a collecting pipe 3kb. The discharge pipes 3ka penetrate the kiln body 3c (and also the refractory material layer 3i if one is installed), connecting the inner cavity of the kiln body 3c with the collecting pipe 3kb, and rotate with the kiln body 3c. The collecting pipe 3kb is a fixed device with an internal mechanical seal to ensure a seal when the discharge pipes 3ka and the collecting pipe 3kb are connected by relative rotation.

[0064] Mechanical grate furnace 4 Figure 2 and Figure 7 As shown, the mechanical grate furnace 4 is a two-section horizontal grate, consisting of a movable grate 4a driven by a movable grate beam and a fixed grate 4b fixed on a fixed grate beam. The movable grate 4a and the fixed grate 4b are arranged alternately in a row of movable and a row of fixed grate beams, with the movable grate 4a repeatedly moving forward and backward. Thus, the material is slowly transported downstream while burning. Each grate section is equipped with an independent air chamber 4c for independent air distribution. Combustion air enters the burning fuel layer through the grate air inlet 8b on the grate bars 4d, ensuring uniform air distribution and cooling the grate bars 4d to prevent burn-out. While ensuring a sufficient air supply, mechanical tumbling is performed, causing unburned materials and carbonaceous residues to burn completely on the grate. The resulting flue gas enters the secondary combustion chamber 5.

[0065] The slag is discharged through the slag hopper 7a and then by the slag discharger 7b. The slag falling through the grate gaps is introduced into the grate slag conveyor 7d via the lower slag hopper 7c, and then sent to the slag discharger 7b. In the 200d / t project, a forward-moving grate is used, with a grate furnace size of 9000×3200mm, consisting of four modules. The grate size is small, significantly smaller than grate furnaces of the same treatment capacity. This is because the solid waste undergoes drying and pyrolysis gasification in the rotary kiln 3, greatly reducing the amount of pyrolysis residue falling into the grate furnace, to only about 60% of the total treatment capacity. Simultaneously, the pyrolysis residue remains on the grate for up to 1 hour, ensuring complete combustion and burnout under sufficient grate air, achieving a loss on ignition rate of less than 3%. Furthermore, the grate bars are made of high-chromium heat-resistant cast steel, possessing extremely strong wear resistance and corrosion resistance, and capable of withstanding high mechanical strength. In summary, the significantly reduced carbon residue, uniform and sufficient grate air, sufficient residence time, ample heating area, and special grate material enable continuous, stable, complete, and efficient combustion of solid waste, and give the incineration process a strong ability to be regulated.

[0066] Under the action of the grate burner 6b and grate air, the mechanical grate furnace 4 ensures that the combustion air is blown out evenly and cools the interior of the mechanical grate furnace 4 to prevent the grate bars 4d from burning out. While ensuring a sufficient air supply, mechanical stirring ensures complete combustion of unburned materials and carbonaceous residues, and the generated flue gas enters the secondary combustion chamber 5. This design allows for a longer residence time of solid waste on the mechanical grate furnace 4 and more uniform grate air distribution, improving the burnout rate and reducing the loss on ignition rate of ash slag. The amount of carbonaceous residue after pyrolysis and gasification is greatly reduced, allowing for a smaller equipment size compared to a standalone grate furnace.

[0067] Of course, the rotary kiln 3 and the mechanical grate furnace 4 in this invention can be arranged in the same direction, or they can be arranged vertically.

[0068] In this embodiment, air-cooled grate technology is used to improve combustion efficiency by using forced cooling air to cool the grate bars 4d. Of course, water-cooled grates can also be used. Water-cooled grate technology uses a separate mechanical grate furnace 4 to incinerate industrial solid waste. The difference from the currently common grate technology is that water cooling is used instead of air cooling, which increases heat exchange efficiency and can better reduce the surface temperature of the grate bars 4d, thus overcoming the limitations of using air-cooled grates for industrial solid waste.

[0069] Second combustion chamber 5 Figure 2 and Figure 8As shown, the combustion chamber 5 includes a medium-temperature zone 5a and a high-temperature zone 5b. The medium-temperature zone 5a is a horizontal rectangular box with a grate furnace installed at the bottom, serving as the main reaction space for the carbonaceous residue of the rotary kiln 3. The front of the medium-temperature zone 5a is connected to the kiln tail 3b of the rotary kiln, with the rotary kiln 3 and grate 4 arranged linearly in sequence. Water-cooled walls 5c are installed on both sides and the top of the front end of the medium-temperature zone 5a. The amount of flue gas entering the medium-temperature zone 5a is controlled by adjusting the height of the kiln tail baffle 3j, preventing overheating of the medium-temperature zone 5a and subsequent coking on the grate and walls. A grate furnace burner 6b is installed on the rear wall of the medium-temperature zone 5a to aid in slag combustion and provide auxiliary heating during start-up and when heat is insufficient. The top of the medium-temperature zone 5a is connected to the high-temperature zone 5b, and a special constriction and flame deflector are designed at the junction of the two zones to enhance flue gas turbulence, ensuring thorough mixing of the flue gas and air, and to strengthen the thermal radiation effect of the high-temperature zone 5b. The high-temperature zone 5b is a vertical, tall, square box housing a secondary combustion chamber burner 6c, a secondary air inlet 8c, and a pyrolysis gas pipe 3k. Part of the combustible gas generated during pyrolysis in the rotary kiln 3 and the flue gas generated from the combustion of pyrolysis residue on the grate are fully combusted in the high-temperature zone 5b of the secondary combustion chamber 5, at a combustion temperature of 1100–1200℃. The residence time of the flue gas in the high-temperature zone 5b of the secondary combustion chamber 5 is ensured to be greater than 2 seconds, guaranteeing complete and thorough combustion of the solid waste entering the incineration system. The bottom of the high-temperature zone 5b is connected to the intermediate-temperature zone 5a of the secondary combustion chamber 5, and an emergency exhaust chimney 5d is installed at the top. A flue gas outlet 5e is located on the side of the top of the high-temperature zone 5b, and the fully combusted high-temperature flue gas is sent to the subsequent waste heat recovery system.

[0070] CFD simulations of the temperature fields in the rotary kiln 3, grate furnace, and secondary combustion chamber 5 revealed that the combined gasification and incineration system of this invention achieves a well-distributed temperature field, and the incineration process is indeed divided into three stages: pyrolysis gasification, secondary incineration of pyrolysis products, and incineration of pyrolysis gas. The temperature inside the rotary kiln 3 is controlled at 550-650℃, the combustion zone of the grate furnace is controlled at approximately 800-900℃, and the temperature in the high-temperature zone 5b of the secondary combustion chamber 5 exceeds 1100℃.

[0071] The combined gasification incineration system provided by this invention decomposes the incineration process of industrial solid waste into three stages: anaerobic pyrolysis gasification, secondary incineration of pyrolysis products, and incineration of pyrolysis gas. The core equipment of this combined gasification incineration system consists of a rotary kiln 3, a mechanical grate furnace 4, and a secondary combustion chamber 5. The three stages of the incineration process are distributed within these three devices. Both the material and primary air enter from the kiln head 3a of the rotary kiln 3, with the primary air volume accounting for only about 20% of the total air supply. Simultaneously, the design length of the rotary kiln 3 is shorter than that in the traditional "rotary kiln 3 + secondary combustion chamber 5" system, only 50-60% of the latter, resulting in a shorter residence time of the material within the rotary kiln 3. Under these conditions, the industrial solid waste in the rotary kiln 3 is gradually dried and pyrolyzed, with the kiln temperature controlled at 550-650℃ to prevent coking due to excessive temperature. The pyrolysis residue from the rotary kiln 3 falls onto the mechanical grate below the outlet, which employs a two-stage grate design: a combustion grate and a burnout grate. The two grate sections are independently air-distributed to ensure complete combustion of the pyrolysis residue on the grate, and the slag is discharged from the tail end of the burnt-out grate. Through a special movable baffle 3j and a pyrolysis gas discharge device 3k, part of the pyrolysis gas in the rotary kiln 3 and the combustion flue gas on the grate enter the secondary combustion chamber 5 under the action of the induced draft fan, and are fully combusted under the action of sufficient secondary air.

[0072] Based on the above structure, the combined gasification and incineration system provided by the present invention has the following technical advantages:

[0073] 1. The low operating temperature inside rotary kiln 3 reduces the risk of coking and extends the service life of refractory materials.

[0074] 2. The amount of combustion air in rotary kiln 3 is small, and the amount of flue gas produced by pyrolysis and gasification is small. Compared with a standalone rotary kiln 3, the equipment size can be greatly reduced.

[0075] 3. The long residence time of solid waste on the grate and the uniform distribution of grate air can improve the combustion rate and reduce the heat loss on ignition rate of ash and slag.

[0076] 4. The amount of carbon residue after pyrolysis and gasification is greatly reduced, which can reduce the size of the equipment compared to a standalone grate furnace.

[0077] 5. The incineration process is broken down and each stage is controlled separately, which can effectively control the combustion process and reduce the amount of nitrogen oxides generated based on fuel nitrogen and thermal nitrogen.

[0078] 6. A movable baffle 3j and a pyrolysis gas bypass are installed at the tail of the rotary kiln 3. The movable baffle 3j controls the flow area of ​​the pyrolysis gas at the kiln tail 3b, thereby transferring the excess flue gas in the middle temperature zone of the kiln tail 3b or the upper part of the mechanical grate furnace 4 to the high temperature zone of the secondary combustion chamber 5. On the one hand, it can flexibly adjust the heat load of the middle temperature zone and the high temperature zone, control the temperature distribution, and increase the combustion efficiency; on the other hand, it can prevent the front of the middle temperature zone and the tail of the rotary kiln 3 from overheating and coking.

[0079] 7. Combining the strong material adaptability of rotary kiln 3 and the strong load adjustment capability of grate, the advantages of rotary kiln 3 and grate are fully utilized, improving the system combustion efficiency and reducing the heat load of secondary combustion chamber 5.

[0080] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0081] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A combined gasification incineration treatment system suitable for industrial solid waste, characterized in that, This includes the rotary kiln feeding system, rotary kiln, mechanical grate furnace, secondary combustion chamber, burner, slag removal system, and air system; The discharge port of the rotary kiln feeding system is connected to the feed port of the rotary kiln, the discharge port of the rotary kiln is connected to the feed port of the mechanical grate furnace, the pyrolysis gas outlet of the rotary kiln is connected to the inlet of the secondary combustion chamber, the length-to-diameter ratio of the rotary kiln is reduced and the length of the rotary kiln is shortened until the rotary kiln undergoes drying, pyrolysis and gasification, the pyrolysis gas outlet of the mechanical grate furnace is connected to the inlet of the secondary combustion chamber, and the pyrolysis residue outlet of the mechanical grate furnace is connected to the inlet of the slag discharge system; The burners include a rotary kiln burner disposed in the rotary kiln, a grate furnace burner disposed in the mechanical grate furnace, and a secondary combustion chamber burner disposed in the secondary combustion chamber; The air system includes a primary air system for supplying air to the rotary kiln, a grate air system for supplying air to the mechanical grate furnace, and a secondary air system for supplying air to the secondary combustion chamber. The secondary combustion chamber includes a medium-temperature zone and a high-temperature zone. The front of the medium-temperature zone is connected to the kiln tail of the rotary kiln. The grate furnace burner is installed at the rear arch of the medium-temperature zone. The top of the medium-temperature zone is connected to the high-temperature zone. A narrowing and flame deflector are designed at the connection between the medium-temperature zone and the high-temperature zone. The rotary kiln includes a kiln head, a kiln tail, a kiln body, a rolling wheel, a transmission mechanism, a reducer, gears, and a sealing device. The kiln head is higher than the kiln tail, and the kiln head is equipped with the rotary kiln burner and the rotary kiln primary air inlet. The rotary kiln tail is provided with a movable baffle at the connection between the kiln tail and the feed inlet of the mechanical grate furnace to adjust the amount of pyrolysis gas entering. The pyrolysis gas outlet of the rotary kiln is connected to the secondary combustion chamber via a pyrolysis gas discharge device. The pyrolysis gas discharge device includes multiple discharge pipes and a manifold. The discharge pipes pass through the kiln body, one end of the manifold is connected to the secondary combustion chamber, and the other end of the manifold extends to the outside of the kiln body and is connected to the multiple discharge pipes through a mechanical seal device.

2. The combined gasification incineration treatment system for industrial solid waste according to claim 1, characterized in that, The length-to-diameter ratio of the rotary kiln is 2-2.

5.

3. The combined gasification incineration treatment system for industrial solid waste according to claim 1, characterized in that, The rotary kiln feeding system includes a feed hopper, a chute, a double-layer flap valve, a pushing device, and a hydraulic station. The feed hopper is connected to the kiln head of the rotary kiln through the chute. The pushing device is used to push industrial solid waste in the chute. The chute is equipped with a double-layer flap valve, which opens and closes alternately to ensure that one valve is closed at any given time.

4. The combined gasification incineration treatment system for industrial solid waste according to claim 1, characterized in that, The mechanical grate furnace is a forward-pushing reciprocating grate, including a movable grate and a fixed grate.

5. The combined gasification incineration treatment system for industrial solid waste according to claim 1, characterized in that, The intermediate temperature zone is a horizontal rectangular box, and the mechanical grate furnace is installed at the bottom of the horizontal rectangular box.

6. The combined gasification incineration treatment system for industrial solid waste according to claim 1, characterized in that, Water-cooled walls are provided on both sides and top of the front end of the intermediate temperature zone.

7. The combined gasification incineration treatment system for industrial solid waste according to claim 1, characterized in that, The high-temperature zone is a vertical, high-square box, which houses the secondary combustion chamber burner and the secondary air inlet for the secondary combustion chamber.

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