Cement kiln system coupled with gasification of biomass solid waste

Abstract

The utility model belongs to the technical field of cement production, and relates to a coupling biomass solid waste gasification cement kiln system, which comprises a rotary kiln and a decomposing furnace, and further comprises a biomass supply device, a solid waste supply device and a plasma gasification furnace, the kiln head hot air pipe is used for supplying kiln head low-temperature hot air to the biomass supply device and the solid waste supply device for drying, and the discharging end of the solid waste supply device and the discharging end of the biomass supply device are both arranged at corresponding feeding ports in the plasma gasification furnace. And a gas outlet of the plasma gasification furnace is connected to a gas inlet of the decomposing furnace. According to the utility model, the residue generated by the gasification furnace can be directly mixed and added into the cement raw material, and the solid waste containing calcium oxide, such as carbide slag, is used as a dechlorinating agent of the product synthesis gas of the gasification furnace, so that the energy of biomass can be fully utilized, the energy consumption is reduced, and the resource utilization of the solid waste is realized.

Description

Technical Field

[0001] The utility model belongs to the technical field of cement production and relates to a cement kiln system coupled with biomass solid waste gasification. Background Art

[0002] In the traditional cement clinker production process, there are a large number of industrial heating processes, of which 30% of carbon emissions come from the combustion of fossil fuels such as coal. In order to achieve carbon neutrality in the cement industry, it is urgent to explore the use of clean energy such as biomass energy and electricity. However, when applying biomass energy and electricity, the following technical problems still exist: when using biomass as an alternative fuel in cement kilns, since biomass contains a large amount of chloride ions, in order to control the chloride ion content of cement clinker, the current main method is to use a decomposition furnace bypass windbreak method to release the raw material containing chloride ions together with the hot air. However, this method not only affects the thermal system of the decomposition furnace, but also causes a huge waste of energy because the released heat energy cannot be fully utilized. Methods for using electricity for industrial heating include resistance heating, arc thermal plasma heating technology, etc. Resistance heating is difficult to couple with cement processes, and MW-level arc thermal plasma technology is still immature. To address the above problems, this patent proposes a cement kiln system coupled with biomass energy solid waste gasification, which can effectively transform the energy structure of the cement process and use solid waste to remove chlorine in the process. Utility Model Content

[0003] The purpose of the utility model is to provide a cement kiln system coupled with biomass solid waste gasification to solve the technical problems in the prior art that biomass contains too much chloride ions and cannot be directly utilized, resulting in high energy consumption, and insufficient gasification effect affecting energy utilization.

[0004] The cement kiln system coupled with biomass solid waste gasification includes a rotary kiln and a decomposition furnace, the kiln tail of the rotary kiln is connected to the bottom of the decomposition furnace, and the cement kiln system also includes a biomass supply device, a solid waste supply device and a plasma gasification furnace. The kiln head chimney outlet of the rotary kiln is connected to a kiln head hot air pipe, and the kiln head hot air pipe is used to supply kiln head low-temperature hot air to the biomass supply device and the solid waste supply device respectively for drying. The discharge end of the solid waste supply device and the discharge end of the biomass supply device are both arranged at the corresponding feed port of the plasma gasification furnace, and the air outlet of the plasma gasification furnace is connected to the air inlet of the decomposition furnace.

[0005] Preferably, the middle portion of the gasification furnace body of the plasma gasification furnace has a constricted structure with a diameter smaller than that of both ends of the gasification furnace body, and an inwardly extending plasma torch is installed on the upper side wall of the slag discharge port at the lower portion of the gasification furnace body.

[0006] Preferably, an air supply pipe is further provided on the side wall of the gasification furnace body. The air supply pipe is arranged on the upper part of the necking structure and extends tangentially into the side wall of the gasification furnace body. There are at least two air supply pipes and they are arranged in pairs. Each pair of air supply pipes is centrally symmetrically arranged around the center of the plasma gasification furnace.

[0007] Preferably, the air outlet of the air supply pipe is inclined upward, and the angle between the air outlet and the horizontal plane is in the range of 5° to 10°.

[0008] Preferably, the gas outlet of the plasma gasification furnace is connected to the gas inlet of the decomposition furnace through a gas pipeline, and the gas pipeline is further connected to an air supply side pipe, and the air supply side pipe is communicated with each air supply pipe.

[0009] Preferably, the biomass supply device includes a biomass silo and a first drying device; the solid waste supply device includes a solid waste silo and a second drying device; the kiln head hot air pipe includes a main pipe part connected to the kiln head of the rotary kiln and two hot air branch pipes connected to the first drying device and the second drying device respectively.

[0010] Preferably, the slag discharge port is provided with an upper and lower slag discharge baffle, which are an upper baffle and a lower baffle respectively, and the upper baffle and the lower baffle can be moved out alternately.

[0011] The utility model has the following advantages: the utility model can solidify chloride ions into the residue in the furnace during the gasification process through the dried and modified solid wastes such as calcium carbide slag and red mud, thereby achieving the effect of removing chlorine. In this way, the residue produced by the gasifier can be directly mixed and added to the cement raw materials, thereby making full use of the energy of the biomass, reducing energy consumption, and realizing the resource utilization of solid waste. The gasification furnace structure in this solution can break up the material and better increase the logistics residence time, thereby improving the gasification effect. This solution can discharge the residue and prevent the airflow from flowing into the slag discharge port through the upper and lower baffles that can be moved out alternately, affecting the combustion of the plasma torch and the gasification effect on the biomass. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is a structural schematic diagram of a cement kiln system coupled with biomass solid waste gasification according to the present invention.

[0013] Figure 2 It is a schematic diagram of the flow chart of the utility model when it is running.

[0014] Figure 3 for Figure 1 Schematic diagram of the structure of the plasma gasification furnace in the shown structure.

[0015] Figure 4 for Figure 3 A cross-sectional view taken along line AA of the structure shown.

[0016] The figure numbers in the accompanying drawings are as follows: 1. Biomass silo, 2. First drying device, 3. Solid waste silo, 4. Second drying device, 5. Plasma gasification furnace, 51. Gasification furnace body, 52. Biomass inlet, 53. Solid waste inlet, 54. Air outlet, 55. Air supply pipe, 56. Upper baffle, 57. Lower baffle, 58. Narrowing structure, 6. Decomposition furnace, 7. Rotary kiln, 8. Plasma torch, 9. Kiln head hot air pipe, 10. Gas pipeline, 11. Air supply side pipe. DETAILED DESCRIPTION

[0017] The following is a further detailed description of the specific implementation methods of the present invention by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0018] like Figures 1-4 As shown, the present invention provides a cement kiln system coupled with biomass solid waste gasification, comprising a rotary kiln 7 and a decomposition furnace 6. The kiln tail of the rotary kiln 7 is connected to the bottom of the decomposition furnace 6. The cement kiln system also includes a biomass supply device, a solid waste supply device, and a plasma gasification furnace 5. The chimney outlet of the rotary kiln 7 is connected to a kiln head hot air pipe 9, which is used to supply low-temperature hot air to the biomass supply device and the solid waste supply device for drying. The discharge ends of the solid waste supply device and the discharge ends of the biomass supply device are both located at corresponding feed ports of the plasma gasification furnace 5. The gas outlet 54 of the plasma gasification furnace 5 is connected to the gas inlet of the decomposition furnace 6. In this way, the system can solidify chloride ions into the furnace residue during the gasification process by drying and modifying solid wastes such as calcium carbide slag and red mud, thereby removing chlorine. This allows the residue generated by the gasification furnace to be mixed and added to the cement raw materials, thereby fully utilizing the energy of the biomass, reducing energy consumption, and achieving resource utilization of solid waste.

[0019] The biomass supply device includes a biomass silo 1 and a first drying device 2. The bottom discharge port of the biomass silo 1 is connected to the feed port of the first drying device 2 via a conveying device 1, and the discharge port of the first drying device 2 is connected to the biomass inlet 52 at the top of the plasma gasification furnace 5 via a conveying device 2. The solid waste supply device includes a solid waste silo 3 and a second drying device 4. The bottom discharge port of the solid waste silo 3 is connected to the feed port of the second drying device 4 via a conveying device 3, and the discharge port of the second drying device 4 is connected to the solid waste inlet 53 at the top of the plasma gasification furnace 5 via a conveying device 4.

[0020] The kiln head hot air pipe 9 comprises a main pipe portion connected to the kiln head of the rotary kiln 7 and two hot air branch pipes connected to the first drying device 2 and the second drying device 4, respectively. This allows the recovery of low-temperature hot air from the kiln head (relatively lower in temperature than the kiln tail) to perform low-temperature thermal drying on the biomass and solid waste in the first drying device 2 and the second drying device 4, respectively. The exhaust gases from the first drying device 2 and the second drying device 4 are purified and then discharged. After drying, the moisture content of the biomass should be controlled within 8%, and the moisture content of the solid waste within 17%. This allows the recovery of low-temperature waste heat and ensures the effective reaction of the biomass and solid waste in the gasifier.

[0021] The gasification furnace body 51 of the plasma gasifier 5 has a constricted structure 58 in the middle, with a smaller diameter than the ends of the gasification furnace body 51. A plasma torch 8 is mounted on the sidewall above the slag discharge port at the lower portion of the gasification furnace 51, extending inward. This solution utilizes the high temperature and high enthalpy characteristics of plasma to gasify biomass into small molecules such as CO, H2, and other combustible gases. Furthermore, a conical funnel structure is formed above the constricted structure 58, thereby increasing the residence time of the material and dispersing it.

[0022] The side wall of the gasification furnace body 51 is also provided with an air supply pipe 55. The air supply pipe 55 is located above the constriction structure 58 and extends tangentially into the side wall of the gasification furnace body 51. There are at least two air supply pipes 55 arranged in pairs, and each pair of air supply pipes 55 is centrally symmetrically arranged around the center of the plasma gasification furnace 5. In this way, external air enters the plasma gasification furnace 5 through the air supply pipe 55, forming a symmetrical swirling airflow within the furnace, which can disperse the material and increase the material residence time. The air supply port of the air supply pipe 55 is tilted upward, and the angle between the air supply port and the horizontal plane ranges from 5° to 10°. This can better increase the logistics residence time, thereby improving the gasification effect.

[0023] The gas outlet 54 of the plasma gasification furnace 5 is connected to the gas inlet of the decomposition furnace 6 via a gas pipeline 10. The gas pipeline 10 is further connected to an air supply side pipe 11. The air supply side pipe 11 is provided with a plurality of outlet branches, each of which is connected to each air supply pipe 55 in a one-to-one correspondence. The air intake main pipe of the air supply side pipe 11 is connected to the side wall of the gas pipeline 10. A centrifugal fan can be installed on the air intake main pipe of the air supply side pipe 11 to increase the air pressure.

[0024] The slag discharge port is equipped with two upper and lower slag discharge baffles: an upper baffle 56 and a lower baffle 57. These baffles can be moved alternately. During slag discharge, the upper baffle 56 is first moved by the first motor, allowing the residue to fall onto the closed lower baffle 57. The upper baffle 56 then closes and the lower baffle 57 opens, allowing the chlorine-containing ash to exit the gasifier. This allows the residue to be discharged while preventing airflow from flowing into the slag discharge port, which could affect the auxiliary combustion of the plasma torch 8 and the gasification of the biomass.

[0025] The working process of this scheme is as follows: After the system is operational, biomass materials and solid waste are simultaneously fed from the biomass supply device and the solid waste supply device to the plasma gasifier 5; after drying, the biomass and solid waste are fed into the plasma gasifier 5 and then gasified by the plasma torch 8. The synthesis gas fuel, such as CO and H2, produced by biomass gasification, enters the decomposition furnace 6 through the gas pipeline for combustion, while the solid waste is dechlorinated during the gasification process. The synthesis gas fuel is also fed into the air supply pipe 55, and then from the air supply pipe 55 into the plasma torch 8 gasifier to generate a symmetrical swirl flow within the furnace. This not only breaks up the materials but also increases their residence time, effectively improving the gasification effect and facilitating the production of synthesis gas fuel. At the same time, since no impurity gas, nitrogen, is introduced, the calorific value of the synthesis gas is not significantly reduced. The residue discharged after gasification can be added to cement as a mixing material, realizing the resource and utilization of solid waste.

[0026] The above is an exemplary description of the present invention in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the inventive concept and technical solution of the present invention, or the inventive concept and technical solution are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A cement kiln system coupled with biomass solid waste gasification, comprising a rotary kiln (7) and a decomposition furnace (6), wherein the kiln tail of the rotary kiln (7) is connected below the decomposition furnace (6), characterized in that: The cement kiln system further comprises a biomass supply device, a solid waste supply device and a plasma gasification furnace (5); a kiln head chimney outlet of the rotary kiln (7) is connected to a kiln head hot air pipe (9); the kiln head hot air pipe (9) is used to supply kiln head low-temperature hot air to the biomass supply device and the solid waste supply device respectively for drying; the discharge end of the solid waste supply device and the discharge end of the biomass supply device are both arranged at corresponding feed ports on the plasma gasification furnace (5); and the air outlet (54) of the plasma gasification furnace (5) is connected to the air inlet of the decomposition furnace (6).

2. The cement kiln system coupled with biomass solid waste gasification according to claim 1, characterized in that: The gasification furnace body (51) of the plasma gasification furnace (5) has a constricted structure (58) in the middle with a diameter smaller than that of the two ends of the gasification furnace body (51), and a plasma torch (8) extending inward is installed on the upper side wall of the slag discharge port at the lower part of the gasification furnace body (51).

3. The cement kiln system coupled with biomass solid waste gasification according to claim 2, characterized in that: An air supply pipe (55) is also provided on the side wall of the gasification furnace body (51). The air supply pipe (55) is provided on the upper part of the necking structure (58) and extends into the tangential direction of the side wall of the gasification furnace body (51). There are at least two air supply pipes (55) and they are arranged in pairs. Each pair of air supply pipes (55) is centrally symmetrically arranged around the center of the plasma gasification furnace (5).

4. The cement kiln system coupled with biomass solid waste gasification according to claim 3, characterized in that: The air supply port of the air supply pipe (55) is inclined upward, and the angle between the air supply port and the horizontal plane is in the range of 5° to 10°.

5. A cement kiln system coupled with biomass solid waste gasification according to claim 3 or 4, characterized in that: The gas outlet (54) of the plasma gasification furnace (5) is connected to the gas inlet of the decomposition furnace (6) via a gas pipeline (10). The gas pipeline (10) is also connected to an air supply side pipe (11), and the air supply side pipe (11) is communicated with each air supply pipe (55).

6. The cement kiln system coupled with biomass solid waste gasification according to claim 1, characterized in that: The biomass supply device comprises a biomass silo (1) and a first drying device (2); the solid waste supply device comprises a solid waste silo (3) and a second drying device (4); the kiln head hot air pipe (9) comprises a main pipe portion connected to the kiln head of the rotary kiln (7) and two hot air branch pipes respectively connected to the first drying device (2) and the second drying device (4).

7. The cement kiln system coupled with biomass solid waste gasification according to claim 2, characterized in that: The slag discharge port is provided with upper and lower slag discharge baffles, namely an upper baffle (56) and a lower baffle (57), and the upper baffle (56) and the lower baffle (57) can be moved out alternately.

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