Heat compensation system for preheating second section of chain grate

Abstract

The invention discloses a heat compensation system for a preheating second section of a chain grate machine, and belongs to the technical field of pellet production. The rotary kiln is communicated with a second preheating section of the chain grate through a kiln tail cover, a plurality of heat supplementing devices are arranged above the second preheating section and used for supplementing heat for a material layer, and an air inducing device is arranged below the chain grate. The method has the beneficial effects that uniform heat compensation of the second preheating section is achieved; the fuel consumption per ton ball is obviously reduced, and the fuel utilization rate is improved; the quality stability of finished balls is improved; stable operation of equipment is realized and the service life of the equipment is prolonged.

Description

Technical Field

[0001] This invention relates to a supplementary heating system for the second preheating stage of a chain grate machine, belonging to the field of pellet production technology. Background Technology

[0002] The chain-loop pelletizing process, with its mature and stable technical characteristics, has been widely used in the metallurgical industry, becoming one of the core processes for ensuring pellet capacity and quality. However, when the raw material is switched to hematite or when alkaline pellets need to be prepared, the traditional method of relying on rotary kilns to heat the chain grate reveals significant shortcomings. It is difficult to match the heat requirements of such special production scenarios, leading to a series of technical defects and production problems.

[0003] First, the reheat burner has structural deficiencies; its installation location cannot fully cover the cross-section of the material layer in the chain grate, resulting in severe uneven heating. Some areas reach the required temperature due to sufficient heat supply, while the edges and corners remain at low temperatures, directly affecting the uniformity of pellet roasting and causing fluctuations in the quality of the finished pellets.

[0004] Secondly, uneven heating further exacerbates potential equipment malfunctions. Localized areas may overheat due to continuous excessive heat intake, causing deformation and burn-out of critical components such as grate bars and chain plates. This not only increases the frequency and cost of equipment maintenance but can also lead to production interruptions due to sudden malfunctions, reducing overall production efficiency.

[0005] In terms of energy consumption and effectiveness, existing heat replenishment methods are trapped in a dilemma of "high consumption and low efficiency". To make up for the heat gap, it is necessary to continuously increase fuel input, which leads to a significant increase in fuel consumption per unit of pellet production. However, the uneven heat distribution greatly reduces the heat replenishment effect and cannot fundamentally meet the roasting heat requirements of hematite and alkaline pellets.

[0006] Furthermore, controlling the reheating process is extremely difficult. Because heat distribution is affected by multiple factors such as burner location and material layer thickness, existing control systems struggle to achieve precise regulation. They cannot optimize reheating uniformity through parameter adjustments, nor can they balance energy consumption with efficiency, causing numerous inconveniences to production operations.

[0007] Chinese utility model patent CN204058557U discloses a heating device for a chain grate machine. This device uses a single-point arrangement, achieving localized combustion heating through a single set of atomizing nozzles. This fails to cover the entire cross-section of the material layer in the chain grate machine, resulting in concentrated heating and an unbalanced temperature distribution: the area directly in front of the nozzle experiences a rapid temperature rise, while the edges and sides of the material layer remain at low temperatures. To achieve the desired heating effect, single-point combustion requires a high diesel fuel supply, and the concentrated heat results in significant heat loss that cannot be effectively absorbed by the material layer. This leads to high fuel consumption per unit of pellet production, failing to achieve the core objective of uniform heating across the entire cross-section, highlighting the technical shortcoming of "high fuel consumption per unit of pellet production without achieving the heating objective." Furthermore, the device lacks a zoned temperature detection and supply adjustment structure, making it impossible to flexibly adjust the heating intensity according to temperature differences in different areas of the material layer. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the purpose of this invention is to provide a supplementary heating system for the preheating stage of a chain grate machine that avoids imbalance in material layer temperature distribution and reduces energy consumption.

[0009] The technical solution of the present invention is: a supplementary heating system for the preheating stage of a chain grate machine, wherein the rotary kiln is connected to the preheating stage of the chain grate machine via a kiln tail hood, and a plurality of supplementary heating devices are provided above the preheating stage, the supplementary heating devices being used to supplement the heating of the material layer, and an induced draft device is provided below the chain grate machine.

[0010] A high-temperature imaging device is installed on the kiln tail cover.

[0011] The heat replenishment device includes an airflow distribution plate located above the second preheating section. The airflow distribution plate is fixed at the bottom of the combustion heat replenishment chamber. The gas pipeline and the combustion-supporting pipeline are connected to the combustion heat replenishment chamber. The gas pipeline is equipped with a flow regulating valve a and a pressure regulating valve a. The combustion-supporting pipeline is connected to the combustion-supporting fan. The combustion-supporting pipeline is equipped with a flow regulating valve b and a pressure regulating valve b.

[0012] The induced draft device includes an induced draft box located below the chain grate machine. The induced draft box is connected to an induced draft pipe, and a dust collector and an induced draft fan are installed on the induced draft pipe.

[0013] The exhaust pipe is connected to the chimney at its end.

[0014] The combustion reheating chamber is equipped with an ignition device.

[0015] The ignition device is an automatic ignition device.

[0016] The beneficial effects of this invention include: It achieves uniform preheating in two stages, and avoids local overheating or underheating of the pellets through precise air distribution and heat source control, laying a stable foundation for subsequent roasting processes. It also performs outstandingly in energy consumption control, with a significant reduction in fuel consumption per ton of pellets and a substantial increase in fuel utilization, which not only reduces raw coal consumption but also lowers carbon emissions and production costs.

[0017] A reasonable temperature gradient is constructed along the operating direction to meet the process requirements of drying and preheating of the pellets, promote the orderly precipitation of internal moisture, and improve the quality stability of the finished pellets. The equipment utilization coefficient is improved, and the equipment size can be reduced under the same production capacity, saving factory space and initial investment. The optimized structural design reduces the fluctuation of equipment operating load, reduces component wear and failure frequency, achieves long-term stable operation, and effectively extends the service life of the equipment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of the present invention. Figure 2 .

[0019] The attached figures are labeled as follows: 1. Rotary kiln; 2. Kiln tail hood; 3. Chain grate; 4. Material layer; 5. High-temperature imager; 6. Airflow distribution plate; 7. Combustion heating chamber; 8. Gas pipeline; 9. Combustion aid pipeline; 10. Flow regulating valve a; 11. Pressure regulating valve a; 12. Flow regulating valve b; 13. Pressure regulating valve b; 14. Exhaust fan box; 15. Exhaust fan pipeline; 16. Dust collector; 17. Exhaust fan; 18. Chimney; 19. Combustion aid fan. Detailed Implementation

[0020] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0023] Secondly, the present invention is described in detail with reference to the schematic diagrams. When describing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include the three-dimensional spatial dimensions of length, width, and depth.

[0024] The following is in conjunction with the appendix Figure 1 —2. Further explanation of the present invention: A supplementary heating system for the preheating stage of a chain grate machine is disclosed. A rotary kiln 1 is connected to the preheating stage of the chain grate machine 3 via a kiln tail hood 2. Several supplementary heating devices are installed above the preheating stage to supplement the heating of the material layer 4. An induced draft device is installed below the chain grate machine 3. The airflow from the supplementary heating devices passes through the material balls and is then drawn out of the preheating stage by the induced draft device. A high-temperature imager 5 is installed on the kiln tail hood 2. The high-temperature imager 5 can simultaneously monitor the supplementary heating status at multiple points and sections. Based on the monitoring results, the combustion state of the supplementary heating devices is adjusted in real time to achieve uniform heating with a temperature gradient.

[0025] The supplementary heating device includes an airflow distribution plate 6 located above the second preheating section. The airflow distribution plate 6 is fixed to the bottom of the combustion supplementary heating chamber 7. The airflow distribution plate 6 is used to form a swirling flow of supplementary heating gas, thereby adjusting the airflow distribution on the cross-section. The gas pipeline 8 and the combustion-supporting pipeline 9 are connected to the combustion supplementary heating chamber 7. The combustion supplementary heating chamber 7 is equipped with an automatic ignition device for igniting the gas. The gas entering the combustion supplementary heating chamber 7 is burned in the combustion supplementary heating chamber 7 under the action of combustion-supporting air, producing high-temperature flue gas. The high-temperature flue gas is carried out of the combustion supplementary heating chamber 7 by the residual pressure of the gas and combustion-supporting air and enters the second preheating section, where it mixes with the low-temperature flue gas provided by the rotary kiln to preheat the material layer. The gas pipeline 8 is equipped with a flow regulating valve a10 and a pressure regulating valve a11. Line 9 is connected to the combustion fan 19. The combustion line 9 is equipped with a flow regulating valve b12 and a pressure regulating valve b13. To create a temperature gradient in the material's running direction, thereby gradually increasing the material's temperature, the supplementary heat needs to be controlled. Specifically, adjusting the opening degree of flow regulating valves a10 and b12 adjusts the intensity of combustion of the gas in the combustion supplementary heating chamber 7, thus regulating the intensity of supplementary heating in different areas, i.e., adjusting the supplementary heating temperature in different areas. Since the hot air volume of the rotary kiln gradually decreases from near to far, the swirling intensity required for uniform mixing with the high-temperature flue gas used for supplementary heating gradually decreases. Adjusting pressure regulating valves a11 and b13 can regulate the swirling intensity. Based on real-time monitoring by the high-temperature imager 5, the supplementary heating temperature and swirling intensity are adjusted. The low-temperature flue gas from the rotary kiln meets the swirling high-temperature flue gas discharged from the heating device. The flue gas is driven to rotate together by the swirling high-temperature flue gas discharged from the heating device. At the same time, the two flue gases of different temperatures are mixed, so that the temperature and flue gas volume can be uniform before entering the material layer.

[0026] The induced draft device includes an induced draft box 14 located below the chain grate machine 3. The induced draft box 14 is connected to an induced draft pipe 15. A dust collector 16 and an induced draft fan 17 are installed on the induced draft pipe 15. The end of the induced draft pipe 15 is connected to a chimney 18. High-temperature flue gas passes through the material layer and preheats the material balls through heat exchange. After heat exchange, the temperature of the flue gas decreases and it is drawn out through the preheating stage by the induced draft device. Specifically, after cooling, the flue gas enters the induced draft pipe 15 through the induced draft box 14 under the action of the induced draft fan 17. After being treated by the dust collector, the flue gas finally enters the chimney 18 and is discharged outdoors.

[0027] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A supplementary heating system for the preheating stage of a chain grate machine, characterized in that, The rotary kiln (1) is connected to the preheating section of the chain grate machine (3) via the kiln tail cover (2). A supplementary heating device is provided above the preheating section to supplement the heating of the material layer (4). An induced draft device is provided below the chain grate machine (3).

2. The supplementary heating system for the preheating stage of a chain grate machine according to claim 1, characterized in that, A high-temperature imaging device (5) is installed on the kiln tail cover (2).

3. The supplementary heating system for the preheating stage of a chain grate machine according to claim 1, characterized in that, The heating device includes several airflow distribution plates (6) located above the preheating section. The airflow distribution plates (6) are fixed at the bottom of the combustion heating chamber (7). The gas pipeline (8) and the combustion-supporting pipeline (9) are connected to the combustion heating chamber (7). The gas pipeline (8) is equipped with a flow regulating valve a (10) and a pressure regulating valve a (11). The combustion-supporting pipeline (9) is connected to the combustion-supporting fan (19). The combustion-supporting pipeline (9) is equipped with a flow regulating valve b (12) and a pressure regulating valve b (13).

4. The supplementary heating system for the preheating stage of a chain grate machine according to claim 1, characterized in that, The air-exhaust device includes an air-exhaust box (14) located below the chain grate machine (3), the air-exhaust box (14) is connected to the air-exhaust pipe (15), and the air-exhaust pipe (15) is equipped with a dust collector (16) and an exhaust fan (17).

5. The supplementary heating system for the preheating stage of a chain grate machine according to claim 4, characterized in that, The exhaust pipe (15) is connected to the chimney (18) at its end.

6. The supplementary heating system for the preheating stage of a chain grate machine according to claim 2, characterized in that, The combustion heating chamber (7) is equipped with an ignition device.

7. The supplementary heating system for the preheating stage of a chain grate machine according to claim 6, characterized in that, The ignition device is an automatic ignition device.

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