Regenerative reduction furnace based on sensible heat in combustion products

Abstract

The utility model discloses a kind of regenerative reduction furnace based on sensible heat in combustion product, the upper end of high support wall and low support wall of the interval interlaced arrangement in its hearth is respectively provided with reduction tank, the combustion flame of regenerative burner of the rear wall of the furnace body is arranged in parallel with the tank body axis of the reduction tank, the regenerative burner is provided with center passage, the middle part of the center passage is provided with honeycomb regenerator, the outer end of the center passage is communicated with three-way reversing valve by gas pipeline, regenerative burner alternate combustion is realized, the periphery of the center passage is provided with natural gas pipeline, the inner end of the natural gas pipeline is communicated with the inner end of the center passage. The utility model uses high-efficiency honeycomb regenerator, greatly recovers sensible heat in combustion product, improves combustion efficiency, reduces CO2 emission by more than 30%, and uses low-oxygen combustion, slows down high-temperature burning loss of reduction tank, reduces the operating cost of enterprise.

Description

Technical Field

[0001] This utility model relates to a reduction furnace combustion technology, and in particular to a regenerative reduction furnace based on the sensible heat in the combustion products. Background Technology

[0002] In existing magnesium reduction furnaces, the burners and reduction tanks are arranged vertically, meaning the burners are mounted on the left and right side walls of the furnace body. The fuels used are low-calorific-value fuels such as producer gas, coke oven gas, and blast furnace gas. In this type of furnace, the burner flame easily comes into direct contact with the reduction tank, causing high-temperature oxidation of the tank. Furthermore, incomplete fuel combustion and significant heat loss are also problems.

[0003] Furthermore, the burner settings of existing reduction furnaces are not suitable for high-calorific-value fuels (such as natural gas), resulting in incomplete fuel combustion, low energy utilization, and short service life of the reduction tank. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of existing calibration technology and provide a regenerative reduction furnace based on the sensible heat in the combustion products that is reasonably designed, capable of preheating and low-oxygen combustion.

[0005] The technical solution of this utility model is: A regenerative reduction furnace based on the sensible heat in combustion products includes a furnace body and a furnace chamber. High support walls and low support walls are alternately arranged within the furnace chamber. A reduction tank is mounted at the upper end of each of the high and low support walls, with the outer end of the reduction tank extending out of the furnace body. Regenerative burners are spaced apart on the rear wall of the furnace body, with the combustion flame of each burner parallel to the axis of the reduction tank. Each burner has a central channel, with a honeycomb-shaped regenerative element in the center. The outer end of the central channel is connected to a gas pipeline, and a natural gas pipeline is arranged around the perimeter of the central channel, with the inner end of the natural gas pipeline connected to the inner end of the central channel. The gas pipeline is connected to a three-way reversing valve for alternating intake and exhaust, enabling alternating combustion by the regenerative burners and promoting uniform temperature and atmosphere within the furnace chamber.

[0006] Furthermore, the outer ends of all the natural gas pipelines are connected to a ring pipe, which is connected to the external natural gas through a port.

[0007] Furthermore, the combustion flame of the regenerative burner is located directly above the reduction tank on the low support wall, with the two corresponding axially.

[0008] Furthermore, the furnace chamber is equipped with partition walls to divide the furnace body into different areas, and the regenerative burners in different areas are respectively controlled to control their combustion or exhaust.

[0009] Furthermore: the furnace body includes a foundation, a front wall, a rear wall, side walls, and a furnace roof. The foundation is made of high-alumina bricks and clay bricks. The furnace roof is composed of furnace roof beams, furnace roof hanging bricks, lightweight castables, and refractory fiberboard. The side walls are composed of steel support frames, lightweight insulating bricks, and high-alumina bricks. The rear wall is composed of low-cement castables and ordinary fiberboard.

[0010] The beneficial effects of this utility model are: 1. This utility model arranges a burner on the rear wall of the furnace body. The flame of the burner is arranged parallel to the axis of the reduction tank and adopts low-oxygen combustion technology, which can reduce the high-temperature burn-off of the reduction tank to a certain extent, help extend the service life of the reduction tank, and reduce the company's operation and maintenance costs.

[0011] 2. This utility model adopts a high-efficiency honeycomb heat storage body to recover the sensible heat in the combustion products to the maximum extent, which is used to preheat the air, improve the combustion efficiency, and reduce the energy consumption of the reduction furnace or CO2 emissions by more than 30%.

[0012] 3. This utility model adopts the technology of high-speed fuel airflow entraining combustion products in the furnace to dilute the oxygen-containing atmosphere in the reaction zone and obtain a low-oxygen atmosphere with a volume fraction of 3% to 15%, so that no local high-temperature and high-oxygen zone appears in the furnace.

[0013] 4. This utility model adopts a honeycomb heat storage body, which has high heat exchange efficiency. The preheating temperature of the air can reach more than 950℃, and the exhaust gas temperature can be reduced to about 150℃.

[0014] 5. The three-way reversing valve of this utility model frequently reverses direction, and the regenerative burner alternates combustion, which promotes uniform temperature and atmosphere in the furnace and enhances heat transfer in the furnace, thereby increasing the furnace production capacity by about 20%.

[0015] 6. In this invention, high-speed, high-temperature air is introduced into the furnace and entrains furnace gas, creating a low-oxygen atmosphere. Fuel burns in this low-oxygen atmosphere, reducing NO₂ levels. x The amount of waste generated is reduced, and the oxidation loss rate of steel is lowered. It is easy to promote and implement, and has good economic benefits. Attached Figure Description

[0016] Figure 1 This is a combustion principle diagram of a regenerative reduction furnace based on the sensible heat in combustion products. Figure 2 This is a structural diagram of a regenerative reduction furnace based on the sensible heat in combustion products; Figure 3 for Figure 1The image shows a top view of a regenerative reduction furnace based on the sensible heat in combustion products. Figure 4 for Figure 2 Sectional view A-A; Figure 5 for Figure 2 Sectional view B-B. Detailed Implementation

[0017] Example: See Figure 1 -- Figure 5 In the diagram, 1-reduction tank, 2-furnace, 3-combustion flame, 4-regenerative burner, 5-three-way reversing valve, 6-high support wall, 7-low support wall, 8-high alumina brick, 9-clay brick, 10-lightweight insulating brick, 11-refractory fiberboard, 12-lightweight castable, 13-furnace top beam, 14-furnace top hanging brick, 15-partition wall, 16-side wall, 17-front wall, 18-ordinary fiberboard, 19-rear wall, 41-regenerative burner in combustion state, 42-regenerative burner in exhaust state, 43-honeycomb regenerator, 44-gas passage, 45-natural gas pipeline.

[0018] A regenerative reduction furnace based on the sensible heat in combustion products is disclosed. The reduction tank 1 is arranged in a single-sided double-row configuration and employs high-temperature air-low-oxygen regenerative combustion technology. Combustion air is switched into the regenerative burner 4 via a three-way reversing valve 5 and heated to approximately 950°C by the honeycomb regenerator 43. After entering the furnace chamber 2, the hot air entrains the surrounding furnace gas, forming a low-oxygen, high-temperature gas flow with an oxygen volume fraction significantly lower than 21%. When the fuel (natural gas) injected into the furnace by the regenerative burner 4 mixes and burns with the low-oxygen atmosphere, heat is released, increasing the temperature of the furnace chamber 2 to approximately 1250°C. The high-temperature furnace gas (flue gas) stores sensible heat in the honeycomb regenerator 43 at the discharge end and is discharged at a low temperature of approximately 150°C through the three-way reversing valve 5, achieving the efficiency of high-temperature furnace gas waste heat recovery.

[0019] The reduction tank 1 is filled with reaction raw material pellets, and the reduction tank 1 is connected to a crystallizer, which is located on the outside of the furnace body.

[0020] A regenerative reduction furnace based on the sensible heat in combustion products consists of a furnace body steel structure, a furnace body foundation, a furnace chamber 2, a furnace top, a front wall 17, a rear wall 19, a side wall 16, a furnace bottom, a regenerative burner 4, a reduction tank 1, a combustion piping system, and a flue gas emission system.

[0021] Furnace body steel structure: Used to fix the refractory masonry or fiber lining of the furnace and ensure the stability and sealing of the masonry or lining, and to bear part of the weight of the lining. It is mainly composed of columns (including front columns, rear columns, and side columns), furnace top beams 13, ring beams, outer wall steel plates, and various steel structures for fixing furnace auxiliary components.

[0022] Furnace lining, also known as masonry, refers to the furnace body components, such as the furnace chamber (2), constructed or laid with refractory and insulating materials. The function of the furnace lining is to enable the industrial furnace to withstand high-temperature loads and resist chemical corrosion during heating, reduce heat loss, and provide sufficient structural strength to ensure the normal operation of the heat exchange process within the furnace. The furnace chamber (2) is made of high-quality refractory materials, zirconium-containing polycrystalline mullite fiber wool, and aluminosilicate fiberboard, possessing excellent refractory and thermal insulation properties, effectively reducing heat loss and improving energy utilization.

[0023] Combustion piping system: The combustion system piping consists of air piping, natural gas piping, furnace drying piping, and auxiliary flue piping.

[0024] Flue gas exhaust system: Consists of ground-mounted exhaust ducts, induced draft fans, chimneys, etc. This system ensures smooth exhaust from the reduction furnace, preventing issues such as increased furnace pressure and large amounts of flue gas escaping from the furnace due to obstructed exhaust, thus reducing heat loss and improving the operating environment.

[0025] The combustion system needs to be periodically switched, and two three-way air reversing valves 5 need to be installed in each combustion section. The three-way reversing valves 5 are relatively close to the regenerative burner 4, which can reduce the furnace switching and shutdown time and the waste of natural gas during switching. When the burners on one side of the section are in the combustion state, the other side is in the flue gas exhaust state.

[0026] The honeycomb heat storage body 43 is made of cordierite and corundum mullite, which has the characteristics of high density, high thermal conductivity, high specific heat capacity and high compressive strength, high temperature resistance, high temperature volume stability, high temperature creep resistance and good thermal shock resistance.

[0027] For high-calorific-value coal gas, a regenerative burner 4 with single air preheating is used. The combustion air flows through the honeycomb regenerator 43 into the furnace. Natural gas enters from the tail end of the burner and exits from the central nozzle. After reversing, the burner undertakes the task of flue gas heat storage. At this time, the natural gas passage is closed by the natural gas quick-cut-off valve.

[0028] This device employs low-oxygen, uniform combustion technology, which not only enhances the radiation and convection exchange of high-temperature flue gas on the reduction tank, but also reduces the scouring and oxidation of the reduction tank by the flame, improves the heating environment of the reduction tank, ensures small temperature differences and good uniformity in all directions of the reduction tank, and effectively extends the service life of the reduction tank.

[0029] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any way. Any simple modifications made based on the technical essence of the present utility model shall still fall within the scope of the technical solution of the present utility model.

Claims

1. A regenerative reduction furnace based on the sensible heat in combustion products, comprising a furnace body and a furnace chamber, wherein high support walls and low support walls are respectively arranged alternately at intervals within the furnace chamber, and a reduction tank is respectively provided at the upper end of each of the high support walls and low support walls, the outer end of the reduction tank extending out of the furnace body, characterized in that: Regenerative burners are arranged at intervals on the rear wall of the furnace body. The combustion flame of the regenerative burner is arranged parallel to the axis of the reduction tank. The regenerative burner is provided with a central channel, and a honeycomb regenerator is provided in the middle of the central channel. The outer end of the central channel is connected to a gas pipeline. A natural gas pipeline is provided around the central channel. The inner end of the natural gas pipeline is connected to the inner end of the central channel. The gas pipeline is connected to a three-way reversing valve to alternate between gas intake and exhaust, so as to realize the alternating combustion of the regenerative burner and promote uniform temperature and atmosphere in the furnace.

2. The regenerative reduction furnace based on the sensible heat in combustion products according to claim 1, characterized in that: The outer ends of all the natural gas pipelines are connected to a ring pipe, which is connected to the external natural gas through a port.

3. A regenerative reduction furnace based on the sensible heat in combustion products according to claim 1, characterized in that: The combustion flame of the regenerative burner is located directly above the reduction tank on the low support wall, with the two corresponding axially.

4. A regenerative reduction furnace based on the sensible heat in combustion products according to claim 1, characterized in that: The furnace chamber is equipped with partition walls, which divide the furnace body into different areas. The regenerative burners in different areas are controlled to either burn or exhaust gas.

5. A regenerative reduction furnace based on the sensible heat in combustion products according to claim 1, characterized in that: The furnace body includes a foundation, a front wall, a rear wall, side walls, and a furnace roof. The foundation is made of high-alumina bricks and clay bricks. The furnace roof is composed of furnace roof beams, furnace roof hanging bricks, lightweight castables, and refractory fiberboard. The side walls are composed of steel support frames, lightweight insulating bricks, and high-alumina bricks. The rear wall is composed of low-cement castables and ordinary fiberboard.

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