Roasting machine capable of recovering hot air in grading mode through energy

Abstract

The utility model provides a roasting machine capable of recovering hot air in an energy grading mode, which comprises a forced air drying section, an air draft drying section, a preheating section, a roasting section, a soaking section, a first cooling section and a second cooling section which are sequentially arranged, and a first furnace cover, a second furnace cover and a third furnace cover are sequentially arranged above a high-temperature section, a medium-temperature section and a low-temperature section of the first cooling section, the first furnace cover is communicated with the hearth of the roasting section, the second furnace cover is communicated with the hearth of the soaking section, and the third furnace cover is communicated with the hearth of the preheating section. According to the roasting machine capable of recovering the hot air in the energy grading mode, the temperature of the roasting section can be increased, so that the fuel consumption is reduced, and the energy utilization is maximized.

Description

Technical Field

[0001] The utility model relates to the technical field of roasting machines, in particular to a roasting machine for hierarchically recovering hot air with energy grading. Background Art

[0002] Pellet ore, as a high-quality raw material for blast furnace ironmaking and direct reduced iron production, has the advantages of high grade, good strength, low process energy consumption, and less harmful gas emissions. Increasing the proportion of pellet ore charged into the furnace and developing high-quality pellet ore, especially fluxed pellet ore and magnesium-containing pellet ore, to improve the quality of ironmaking has become an inevitable trend and meets the strategic needs of the green development of the steel industry. With the change of global raw material conditions, high-quality pellet raw materials are becoming fewer and fewer. The traveling grate roasting machine has the advantages of strong raw material adaptability, low fuel consumption, high equipment reliability, and good environmental protection indicators, and has gradually replaced the grate-kiln process to become the mainstream technology for green development and technological upgrading.

[0003] The patent with the publication number CN219756939U discloses a traveling grate roasting machine for hierarchical cooling and cascade utilization of hot air, including: the first cooling section, the second cooling section, and the third cooling section. The hot air temperatures generated by the first cooling section, the second cooling section, and the third cooling section are not less than 1100°C, 600 - 800°C, and not more than 300°C respectively, and the generated hot air is respectively transported to the roasting section, the preheating section, and the blast drying section through pipelines. By grading the cooling section and providing hot air at different temperatures for the roasting section, the preheating section, and the blast drying section respectively, the cascade utilization of heat is realized, the energy utilization rate is improved, the process energy consumption is reduced, and low calorific value fuels can be used while reducing the process energy consumption.

[0004] The above patent only simply separates the cooling section and transports it to different process sections, and the hottest hot air still enters the soaking section first, resulting in a low thermal energy utilization rate; the second cooling section and the third cooling section share one cooling fan, and the furnaces of the preheating and roasting sections are connected, resulting in pressure fluctuations and affecting the air volume distribution of the cooling fan; the cold air in the first cooling section directly contacts the high-temperature pellets, causing rapid cooling of the pellets and generating stress, resulting in cracks in the pellets. Summary of the Utility Model

[0005] The main purpose of the utility model is to provide a roasting machine for hierarchically recovering hot air with energy grading, aiming to increase the temperature of the roasting section, thereby reducing the fuel consumption and maximizing the energy utilization.

[0006] To achieve the above purpose, the utility model provides a roasting machine for hierarchically recovering hot air with energy grading, including a blast drying section, a suction drying section, a preheating section, a roasting section, a soaking section, a first cooling section, and a second cooling section arranged in sequence. It is characterized in that a first furnace hood, a second furnace hood, and a third furnace hood are sequentially arranged above the high-temperature section, the medium-temperature section, and the low-temperature section of the first cooling section. Among them,

[0007] The first furnace hood is communicated with the furnace of the roasting section, the second furnace hood is communicated with the furnace of the soaking section, and the third furnace hood is communicated with the furnace of the preheating section.

[0008] Preferably, a burner is also installed on the channel between the second furnace hood and the soaking section to supplement the heat of the hot air recovered from the medium temperature section.

[0009] Preferably, a fourth furnace hood is provided above the second cooling section, and an outlet of the fourth furnace hood is connected to an air inlet of the blast drying section through a pipeline.

[0010] Preferably, partition walls are provided between the forced air drying section and the exhaust air drying section, between the exhaust air drying section and the preheating section, between the roasting section and the soaking section, between the soaking section and the first cooling section, and between the first cooling section and the second cooling section.

[0011] Preferably, the wind box exhaust gas at the rear end of the roasting section and the soaking section is connected to the hot air inlet of the exhaust drying section through a pipeline.

[0012] Preferably, the hot air inlet of the exhaust drying section is also connected to the exhaust gas outlet of the first wind box of the preheating section through a pipeline.

[0013] Preferably, a heat recovery fan is installed on the pipeline between the exhaust gas outlet of the bellows and the hot air inlet of the exhaust drying section.

[0014] Preferably, a cold air valve is provided at the inlet of the heat recovery fan.

[0015] Preferably, the hot air outlet of the heat recovery fan is also connected to the front smoke hood inlet and outlet of the preheating section.

[0016] Preferably, the hot flue gas at the front end of the exhaust drying section, the preheating section and the roasting section is also connected to the main exhaust fan through a pipeline to be extracted to the chimney.

[0017] The roasting machine proposed in the utility model can make full use of the hot air energy in the system and make the hot air temperature correspond to the process partition. The hot air after the heat exchange in the first cold section is diverted through the hot air grading system. The high-temperature hot air is different from the prior art that directly goes to the equalizing section, but is sent to the roasting section through the high-temperature section, thereby reducing fuel consumption and maximizing energy utilization; low calorific value fuel can be used for the roasting pellet process; a small amount of cheap low calorific value gas is used to supplement heat in the medium temperature section, which is very economical; the oxidizing atmosphere of the roasting section and the equalizing section does not change, and does not affect the process reaction; the waste gas is recycled to reduce emissions, improve the thermal efficiency of the roasting machine, and achieve energy conservation and emission reduction. The structure is simple, the layout is reasonable, and the thermal utilization rate is high, which is worthy of application and promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a preferred embodiment of the utility model of a roasting machine for energy graded hot air recovery.

[0019] In the figure, 1 is the hood fan, 2 is the air drying fan, 3 is the main exhaust fan, 4 is the recuperative air fan, 5 is the first cooling air fan, 6 is the second cooling air fan, 7 is the cold air valve, 8 is the burner, 9 is the high temperature section, 10 is the medium temperature section, 11 is the low temperature section, 12 is the partition wall, 13 is the hood, 14 is the furnace chamber, 15 is the air box, 16 is the air drying section, 17 is the exhaust drying section, 18 is the preheating section, 19 is the roasting section, 20 is the soaking section, 21 is the first cooling section, and 22 is the second cooling section.

[0020] The realization, functional features and advantages of the purpose of the present utility model will be further described with reference to the embodiments and the accompanying drawings. Specific embodiments

[0021] It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0022] It should be noted that in the description of the present utility model, the orientation or positional relationship indicated by the terms "horizontal", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation of the present utility model. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0023] Referring to Figure 1 , in this preferred embodiment, a roasting machine for energy - graded recovery of hot air includes an air drying section 16, an exhaust drying section 17, a preheating section 18, a roasting section 19, a soaking section 20, a first cooling section 21, and a second cooling section 22 arranged in sequence. Above the high temperature section 9, medium temperature section 10, and low temperature section 11 of the first cooling section 21, a first hood, a second hood, and a third hood are arranged in sequence. Among them,

[0024] The first hood is communicated with the furnace chamber 14 of the roasting section 19 (thus effectively increasing the temperature of the furnace chamber 14 of the roasting section 19), the second hood is communicated with the furnace chamber 14 of the soaking section 20, and the third hood is communicated with the furnace chamber 14 of the preheating section 18 (the low temperature section 11 is connected to the preheating section 18. Since there is no partition wall 12 between the preheating section 18 and the roasting section 19, a natural temperature gradient with the front low and the rear high can be formed in the furnace chamber 14).

[0025] In addition, partition walls 12 are provided between the air-blowing drying section 16 and the air-exhausting drying section 17, between the air-exhausting drying section 17 and the preheating section 18, between the roasting section 19 and the soaking section 20, between the soaking section 20 and the first cooling section 21, and between the first cooling section 21 and the second cooling section 22, so as to prevent air leakage between the various process sections of the roasting machine.

[0026] In this embodiment, connecting the high-temperature section 9 to the roasting section 19 can effectively increase the temperature of the furnace chamber 14 of the roasting section 19, reduce fuel consumption, and also enable the use of low-calorific-value fuels; connecting the low-temperature section 11 to the preheating section 18, since there is no partition wall 12 between the preheating section 18 and the roasting section 19, a natural temperature gradient with a lower front and a higher rear can be formed in the furnace chamber 14.

[0027] Furthermore, a burner 8 is installed on the passage between the second furnace hood and the soaking section 20 to supplement heat to the hot air recovered from the medium-temperature section 10, thereby ensuring the temperature of the soaking section 20.

[0028] The function of the soaking section 20 is to ensure that the temperatures of the upper and lower material layers are uniform and reduce the content of ferrous oxide. Therefore, the hot air needs to have sufficient oxygen content. Connecting the medium-temperature section 10 to the soaking section 20 and cooperating with the supplementary burner 8, the temperature is raised to 1100 °C through heat supplementation by the burner 8, and at the same time, the oxygen content of the mixed hot air is still above 18%, meeting the process requirements.

[0029] Furthermore, in this embodiment, a fourth furnace hood is provided above the second cooling section 22. The outlet of the fourth furnace hood is connected to the air inlet of the air-blowing drying section 16 through a pipeline. A drying air blower 2 is installed on the outlet pipeline of the fourth furnace hood.

[0030] The drying air blower 2 sends the hot air from the second cooling section 22 into the bottom air box 15 of the air-blowing drying section 16 to dry the green pellet material layer. The dried flue gas is discharged into the chimney through the furnace hood connecting the furnace hood blower 1.

[0031] Furthermore, in this embodiment, the waste gas from the air boxes 15 at the rear end of the roasting section 19 and the soaking section 20 is connected to the hot air inlet of the air-exhausting drying section 17 through a pipeline, thereby reducing the amount of cold air incorporated.

[0032] Furthermore, the hot air inlet of the air-exhausting drying section 17 is also connected to the waste gas outlet of the first air box 15 of the preheating section 18 through a pipeline.

[0033] Furthermore, a heat recovery blower 4 is installed on the pipeline between the waste gas outlet of the air box 15 and the hot air inlet of the air-exhausting drying section 17, thereby improving the flue gas circulation efficiency.

[0034] In this embodiment, a cold air valve 7 is provided at the inlet of the regenerative air blower 4 to facilitate temperature adjustment. The hot air outlet of the regenerative air blower 4 is also communicated with the inlet and outlet of the front flue hood of the preheating section 18. In this way, the waste flue gas in the first air box 15 of the preheating section 18 circulates reciprocally in the whole system, reducing the total emission. The hot air in the preheating section 18 mainly comes from the low-temperature section 11, and at the same time, a small part of the hot air from the regenerative air blower 4 is introduced at the front end to adjust the temperature.

[0035] In this embodiment, the hot flue gas at the front ends of the air extraction and drying section 17, the preheating section 18 and the roasting section 19 is also communicated with the main exhaust fan 3 through a pipeline to be drawn to the chimney. Before entering the chimney, the flue gas needs to be purified.

[0036] The working process of this roasting machine is as follows: Cold air is blown into the bottom air box 15 of the first cooling section 21 by a first cooling fan 5 to cool the high-temperature material layer. After passing through the material layer, the cold air is heated and enters the hot air grading system; Cold air is blown into the bottom air box 15 of the second cooling section 22 by a second cooling fan 6 to continue cooling the material layer. The hot air after heat exchange is introduced into the air blowing and drying section 16 by the air blowing and drying fan 2 to dry the green balls.

[0037] The roasting machine proposed in this embodiment can make full use of the hot air energy in the system to make the hot air temperature correspond to the process partition. The hot air after heat exchange in the first cooling section 21 is shunted through the hot air grading system. Different from the prior art that the high-temperature hot air directly goes to the soaking section 20, it is sent to the roasting section 19 through the high-temperature section 9, thus reducing the fuel consumption and maximizing the energy utilization; Therefore, low calorific value fuel can be used for the roasting pellet process; A small amount of cheap low calorific value gas is used in combination to supplement heat to the medium-temperature section 10, which has high economy; The oxidation atmosphere in the roasting section 19 and the soaking section 20 has not changed and does not affect the process reaction; The waste gas is recycled, the emission is reduced, the thermal efficiency of the roasting machine is improved, and energy conservation and emission reduction are realized. This structure is simple, the layout is reasonable, and the thermal utilization rate is high, which is worthy of application and promotion.

[0038] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structural transformation made by using the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present invention by the same token.

Claims

1. A roasting machine for energy graded hot air recovery, comprising a blast drying section, an exhaust drying section, a preheating section, a roasting section, a soaking section, a first cooling section and a second cooling section arranged in sequence, characterized in that: A first furnace cover, a second furnace cover and a third furnace cover are sequentially arranged above the high temperature section, the medium temperature section and the low temperature section of the first cold section, wherein: The first furnace hood is communicated with the furnace of the roasting section, the second furnace hood is communicated with the furnace of the soaking section, and the third furnace hood is communicated with the furnace of the preheating section.

2. The roasting machine for energy graded hot air recovery according to claim 1, characterized in that: A burner is also installed on the channel between the second furnace hood and the soaking section to supplement the heat of the hot air recovered from the medium temperature section.

3. The roasting machine for energy graded hot air recovery according to claim 1, characterized in that: A fourth furnace cover is arranged above the second cooling section, and an outlet of the fourth furnace cover is connected with an air inlet of the blast drying section through a pipeline.

4. The roasting machine for energy graded hot air recovery according to claim 1, characterized in that: Partition walls are arranged between the blast drying section and the exhaust drying section, between the exhaust drying section and the preheating section, between the roasting section and the soaking section, between the soaking section and the first cooling section, and between the first cooling section and the second cooling section.

5. The roasting machine for energy graded hot air recovery according to claim 1, characterized in that: The wind box exhaust gas at the rear end of the roasting section and the soaking section is connected to the hot air inlet of the exhaust drying section through a pipeline.

6. The roasting machine for energy graded hot air recovery according to claim 5, characterized in that: The hot air inlet of the exhaust drying section is also connected to the exhaust gas outlet of the first wind box of the preheating section through a pipeline.

7. The roasting machine for energy graded hot air recovery according to claim 6, characterized in that: A heat recovery fan is installed on the pipeline between the exhaust gas outlet of the bellows and the hot air inlet of the exhaust drying section.

8. The roasting machine for energy graded hot air recovery according to claim 7, characterized in that: A cold air valve is provided at the inlet of the heat recovery fan.

9. The roasting machine for energy graded hot air recovery according to claim 7, characterized in that: The hot air outlet of the heat recovery fan is also connected to the front section smoke hood inlet and outlet of the preheating section.

10. The roasting machine for energy graded hot air recovery according to any one of claims 1 to 9, characterized in that: The hot flue gas at the front end of the exhaust drying section, the preheating section and the roasting section is also connected to the main exhaust fan through a pipeline to be extracted to the chimney.

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