CN107815516B - External heating type coal-based vertical furnace for producing direct reduced iron - Google Patents

Abstract

The invention relates to an external heating type coal-based vertical furnace for producing direct reduced iron, wherein cooling chamber walls on two sides of a cooling chamber are respectively provided with a cooling gas channel along the height direction, each cooling gas channel is provided with a plurality of cooling gas outlets or cooling gas inlets, and the cooling gas outlets and the cooling gas inlets are communicated with the inner space of the cooling chamber; the top of the upper regenerator is provided with a top converging air passage communicated with the top of the combustion chamber, and the bottom of the upper regenerator is provided with a small flue of the upper regenerator; the top of the lower heat storage chamber is provided with a lower heat storage chamber small flue, and the bottom of the lower heat storage chamber is provided with a bottom converging air passage communicated with the bottom of the combustion chamber. The invention concentrates the oxidation reaction of fuel combustion, gasification reaction of raw materials, reduction reaction of raw materials, cooling process of generated sponge iron and process of recovering high-temperature flue gas waste heat in the direct reduction iron-making process in the vertical furnace, and has the characteristics of reasonable furnace body structure, long furnace body service life, high thermal efficiency, low auxiliary equipment investment, easy realization of engineering and the like.

Description

An externally heated coal-based vertical furnace for the production of direct reduced iron

technical field

The invention relates to the technical field of vertical furnaces, in particular to an externally heated coal-based vertical furnace for producing direct reduced iron.

Background technique

The direct reduction ironmaking process (DRI) refers to the process of refining iron ore into metallic iron through reduction in the solid state at a temperature lower than the melting temperature of iron ore, and its product is called sponge iron. Sponge iron is an essential raw material for smelting high-quality special steel. High-quality high-quality special steel products are widely used in power station, metallurgy, petrochemical, aviation and marine equipment fields, and the demand is increasing rapidly. However, the output of direct reduced iron in my country is less than one million tons, less than 1% of the world's direct reduced iron output, far below the world average level. Overproduction of low-end products and insufficient production of high-end products have become problems that my country's steel industry needs to solve urgently.

Direct reduction ironmaking is divided into gas-based direct reduction and coal-based direct reduction according to the process, and is divided into rotary kiln, rotary hearth furnace, reaction tank, tube furnace and fluidized bed according to the main equipment. At present, more than 90% of the direct reduced iron in the world is produced by the gas-based reduction method. However, my country's natural gas resources are limited and the price is high. Gas-based reduction is not suitable for my country's national conditions of more coal and less gas. Rotary kiln technology, rotary hearth furnace technology, and tunnel kiln technology all have problems such as high energy consumption, difficult control of the production process, and low product quality.

Domestic researchers have also done some research on external thermal direct reduction of coal, such as the patent "External Combustion Tube Type Direct Reduction Shaft Furnace" with publication number CN101832706A, and the patent "External Thermal Direct Reduction of Coal-based Direct Reduction of Iron" with publication number CN201166513. Shaft Furnace", the publication number is CN 204529897 U "A kind of external heating type coal-based shaft furnace for producing direct reduced iron", etc. The above disclosed technologies all have a too simple structure of the furnace body. The shaft furnace only includes the oxidation reaction of fuel combustion, the gasification reaction of raw materials and the reduction reaction of raw materials. The life of the furnace body is short, the thermal efficiency is low, and it is difficult to engineer. Moreover, they all adopt the cooling method of cooling the high-temperature sponge iron outside the furnace with water-cooled equipment, which requires high temperature resistance for the discharge equipment and water-cooled equipment, and requires a large investment in equipment.

Contents of the invention

The invention provides an externally heated coal-based vertical furnace for producing direct reduced iron, the oxidation reaction of fuel combustion in the direct reduction ironmaking process, the gasification reaction of raw materials, the reduction reaction of raw materials, the generated sponge iron The cooling process and the process of recovering high-temperature flue gas waste heat are concentrated in the vertical furnace, which has the characteristics of reasonable furnace structure, long furnace life, high thermal efficiency, low investment in auxiliary equipment, and easy engineering.

In order to achieve the above object, the present invention adopts the following technical solutions to realize:

An externally heated coal-based vertical furnace for the production of direct reduced iron, including a reduction chamber, a combustion chamber, a furnace roof, a regenerator and a cooling chamber; the combustion chamber, the reduction chamber, and the cooling chamber occupy one side of the furnace body, and the heat storage The chamber occupies the other side of the furnace body; the combustion chamber and the reduction chamber are distributed alternately, the cooling chamber is located below the reduction chamber, and the top of the cooling chamber communicates with the reduction chamber; the furnace top is located on the upper part of the combustion chamber; the regenerator includes the upper regenerator and The lower regenerator, one end of the upper regenerator and the lower regenerator communicate with the combustion chamber, and the other end is connected with the waste gas switch. Both the upper regenerator and the lower regenerator are equipped with checkered bricks; Cooling gas passages are respectively arranged in the cooling chamber wall on the side, and multiple cooling gas passages are uniformly arranged along the height of the cooling chamber, and each cooling gas passage is uniformly provided with multiple cooling gas outlets or cooling gas inlets along the The gas outlet and the cooling gas inlet are connected to the inner space of the cooling chamber; the top of the upper regenerator is provided with a top converging air passage to communicate with the top of the combustion chamber, and the bottom is provided with a small flue in the upper regenerator; the top of the lower regenerator A small flue is provided in the lower regenerator, and a bottom converging air passage is provided at the bottom to communicate with the bottom of the combustion chamber.

The opening direction of the cooling gas inlet or the cooling gas outlet faces obliquely downward inside the cooling chamber respectively.

The cooling gas inlet and the cooling gas outlet are arranged oppositely; that is, cooling gas inlets are provided on the cooling gas passages in the cooling chamber wall on one side of the cooling chamber, and cooling gas outlets are provided on the cooling gas passages in the cooling chamber wall on the other side.

Cooling gas inlets are provided on the cooling gas passages at the bottom of the cooling chamber walls on both sides of the cooling chamber, and cooling gas outlets are provided on the cooling gas passages at the top of the cooling chamber walls on both sides.

The cooling gas channel, the cooling gas inlet and the cooling gas outlet are respectively built by refractory bricks, or are composed of stainless steel pipes pierced in the refractory bricks.

The reduction chambers are single-row reduction chambers, double-row reduction chambers or three-row reduction chambers. The upper opening of the reduction chamber is narrow along the width direction and the lower opening is wider, and the width of the lower opening of the reduction chamber is 10 mm to 200 mm wider than the width of the upper opening of the reduction chamber; the cooling chamber The width of the upper opening is the same as that of the lower opening of the reduction chamber.

The upper regenerator and the lower regenerator form a unit regenerator, and each unit regenerator corresponds to the combustion chamber one by one.

Compared with prior art, the beneficial effect of the present invention is:

1) The structure of the vertical furnace body is reasonable, the heat transfer condition is good, and the life of the furnace body is long;

2) The regenerator can recover the waste heat of the flue gas to preheat the air for combustion, and the thermal efficiency of the vertical furnace is high;

3) Easy to operate, adjustable air flow, easy to control combustion temperature and speed, reduce high temperature points, thereby reducing the generation of NOx, which is more conducive to environmental protection;

4) The cooling chamber can realize the rapid cooling of the product sponge iron in the furnace, which reduces the ultra-high temperature resistance requirements for the cooling equipment outside the furnace, reduces the investment in auxiliary equipment, and improves production efficiency at the same time.

Description of drawings

Fig. 1 is a longitudinal sectional view of the furnace body of the vertical furnace of the present invention.

Fig. 2 is a view of A-A in Fig. 1 .

Fig. 3 is a first schematic diagram of the distribution of cooling gas inlets and cooling gas outlets according to the present invention.

Fig. 4 is a second schematic diagram of the distribution of cooling gas inlets and cooling gas outlets according to the present invention.

In the figure: 1. Furnace top charging port 2. Furnace top 3. Combustion chamber 4. Reduction chamber 5. Cooling chamber 6. Cooling gas channel 7. Combustion chamber wall 8. Cooling chamber wall 9. Upper heat storage chamber sealing wall 10 .Lattice bricks in the upper regenerator 11. Partition wall between the regenerator and the combustion chamber 12. Small flue in the upper regenerator 13. Small flue in the lower regenerator 14. Sealing wall in the lower regenerator 15. Lower heat storage Indoor lattice brick 16. Partition wall in the middle of the combustion chamber 17. Standing fire passage partition wall 18. Standing fire passage 19. Combustion chamber sealing wall 20. Cooling gas inlet 21. Cooling gas outlet 22. Upper opening of the cooling chamber

detailed description

The specific embodiment of the present invention will be further described below in conjunction with accompanying drawing:

As shown in Figures 1 and 2, an externally heated coal-based vertical furnace for producing direct reduced iron according to the present invention includes a reduction chamber 4, a combustion chamber 3, a furnace roof 2, a heat storage chamber and a cooling chamber 5 The combustion chamber 3, the reduction chamber 4, and the cooling chamber 5 occupy one side of the furnace body, and the regenerator occupies the other side of the furnace body; the combustion chamber 3 and the reduction chamber 4 are distributed alternately, and the cooling chamber 5 is located below the reduction chamber 4. The top of 5 communicates with the reduction chamber 4; the furnace top 2 is located at the top of the combustion chamber 3; the regenerator includes an upper regenerator and a lower regenerator, and one end of the upper regenerator and the lower regenerator communicates with the combustion chamber 3, The other end is connected with the exhaust gas switch, and the upper regenerator and the lower regenerator are equipped with checker bricks 10/15; the cooling chamber walls 8 on both sides of the cooling chamber 5 are respectively provided with cooling gas passages 6, and multiple The cooling gas channels 6 are evenly arranged along the height of the cooling chamber 5, and each cooling gas channel 6 is uniformly provided with a plurality of cooling gas outlets 21 or cooling gas inlets 20 along the length of the cooling chamber 5, and the cooling gas outlets 21, the cooling gas inlets 20 and the The internal space of the cooling chamber 5 is connected; the top of the upper regenerator is provided with a top converging air passage to communicate with the top of the combustion chamber 3, and the bottom of the upper regenerator is provided with a small flue 12; the top of the lower regenerator is provided with a lower heat storage Chamber small flue 13, the bottom of which is provided with the bottom converging gas passage to communicate with the bottom of combustion chamber 3.

The opening direction of the cooling gas inlet 20 or the cooling gas outlet 21 faces obliquely downward inside the cooling chamber 5 respectively.

As shown in Figure 3, the cooling gas inlet 20 and the cooling gas outlet 21 are arranged oppositely; that is, the cooling gas passage 6 in the cooling chamber wall 8 on one side of the cooling chamber 5 is provided with a cooling gas inlet 20, and the cooling chamber on the other side Cooling gas outlets 21 are provided on the cooling gas passages 6 in the wall 8 .

As shown in Figure 4, cooling gas inlets 20 are provided on the cooling gas passages 6 at the bottom of the cooling chamber walls 8 on both sides of the cooling chamber 5, and cooling gas outlets are provided on the cooling gas passages 6 at the top of the cooling chamber walls 8 on both sides. twenty one.

The cooling gas channel 6 , the cooling gas inlet 20 and the cooling gas outlet 21 are respectively made of refractory bricks, or are composed of stainless steel pipes pierced in the refractory bricks.

The reduction chamber 4 is a single-row reduction chamber, a double-row reduction chamber or a three-row reduction chamber. The reduction chamber 4 has a narrow upper opening and a wider lower opening along the width direction, and the width of the lower opening of the reduction chamber is 10 mm to 200 mm larger than the width of the upper opening of the reduction chamber; The width of the upper opening 22 of the cooling chamber is the same as that of the lower opening of the reduction chamber.

The upper regenerator and the lower regenerator form a unit regenerator, and each unit regenerator corresponds to the combustion chamber 3 one by one.

The combustion chamber 3 of the vertical furnace is composed of the vertical fire passage 18, the vertical fire passage partition wall 17, the middle partition wall 16 of the combustion chamber, the reduction chamber wall, the combustion chamber wall 7 and the combustion chamber sealing wall 19; the reduction chamber 4 is composed of the reduction chambers on both sides Wall, regenerator wall, sealing wall, iron parts for protecting the furnace at the charging port and iron parts for protecting the furnace at the discharge port are enclosed. The furnace iron parts are enclosed and composed. A regenerator partition wall is set between the upper regenerator and the lower regenerator, and a partition wall 11 between the regenerator and the combustion chamber is set on the side adjacent to the upper regenerator, the lower regenerator and the combustion chamber, and the other side is respectively An upper regenerator sealing wall 9 and a lower regenerating chamber sealing wall 14 are provided. The top of the furnace is provided with a charging port 1 on the top of the furnace.

In the present invention, the cooling gas transported by the corresponding cooling gas channel 6 enters the cooling chamber 5 through the cooling gas inlet 20, and the cooling gas flows horizontally or upwardly in the cooling chamber 5, and directly exchanges heat with the high-temperature sponge iron flowing downward, The high temperature sponge iron at 800°C-1000°C can be cooled to the range of 100°C-350°C, and the cooling gas after heat exchange leaves the cooling chamber 5 through the cooling gas outlet 21 through the corresponding cooling gas channel 6. The cooling gas is the gas produced by the direct reduction ironmaking reaction, mainly a mixture of carbon monoxide and carbon dioxide, and inert gases such as nitrogen can also be used.

The cooling gas channel 6 provided with the cooling gas inlet 20 is respectively connected to the furnace gas pipeline (the fan positive pressure outlet end), and the cooling gas channel 6 provided with the cooling gas outlet 21 is respectively connected to the suction pipe (the fan negative pressure inlet port) .

The upper regenerator and the lower regenerator form a unit regenerator, and each unit regenerator is set in one-to-one correspondence with the combustion chamber 3, and the temperature of the combustion chamber vertical fire channel 18 is highly adjustable.

In the first exchange cycle, the air enters the small flue 12 of the upper regenerator through the waste gas switch, and after being preheated by the checker bricks 10 in the upper regenerator, it enters the vertical fire channel 18 of the combustion chamber through the confluent air channel at the top to participate in the process. Combustion, the hot exhaust gas after combustion enters the bottom confluence air passage through the bottom of the combustion chamber 3, and after heat exchange with the checker brick 15 in the lower regenerator, it enters the chimney through the small flue 13 of the lower regenerator through the waste gas switch;

In the second exchange cycle, the air enters the small flue 13 of the lower regenerator through the waste gas switch, and after being preheated by the checker bricks 15 in the lower regenerator, the air enters the combustion chamber vertical fire channel 18 through the confluent air channel at the bottom. Participate in the combustion, the hot exhaust gas after combustion enters the top confluence air passage through the top of the combustion chamber 3, and after heat exchange with the checker brick 10 in the upper regenerator, it enters the chimney through the small flue 12 of the upper regenerator through the waste gas switch ;

In different exchange cycles, the airflow resistance through the upper regenerator and the lower regenerator is the same or similar, the pressure distribution in the vertical fire channel 18 is more stable, and the temperature fluctuation in the production process is highly controllable, which is conducive to reducing nitrogen oxide emissions quantity.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto, any person familiar with the technical field within the technical scope disclosed in the present invention, according to the technical solution of the present invention Any equivalent replacement or change of the inventive concepts thereof shall fall within the protection scope of the present invention.

Claims (7)

1. An externally heated coal-based vertical furnace for producing direct reduced iron, comprising a reduction chamber, a combustion chamber, a furnace top, a regenerator and a cooling chamber; the combustion chamber, the reduction chamber, and the cooling chamber occupy one side of the furnace body, The regenerator occupies the other side of the furnace body; the combustion chamber and the reduction chamber are distributed alternately, the cooling chamber is located below the reduction chamber, and the top of the cooling chamber communicates with the reduction chamber; the furnace top is located on the upper part of the combustion chamber; the regenerator includes the upper heat storage chamber chamber and the lower regenerator, one end of the upper regenerator and the lower regenerator communicates with the combustion chamber, and the other end is connected with the exhaust gas switch, and both the upper regenerator and the lower regenerator are equipped with lattice bricks; it is characterized in that , the cooling chamber walls on both sides of the cooling chamber are respectively provided with cooling gas passages, a plurality of cooling gas passages are arranged uniformly and horizontally along the height of the cooling chamber, and each cooling gas passage is uniformly provided with a plurality of cooling chambers along the long direction of the cooling chamber The gas outlet or the cooling gas inlet, the cooling gas outlet and the cooling gas inlet are in communication with the inner space of the cooling chamber; the top of the upper regenerator is provided with a top converging gas channel connected to the top of the combustion chamber, and the bottom is provided with a small flue of the upper regenerator; The top of the lower regenerator is provided with a small flue in the lower regenerator, and the bottom is provided with a bottom converging gas channel to communicate with the bottom of the combustion chamber. 2 . The externally heated coal-based vertical furnace for producing direct reduced iron according to claim 1 , wherein the opening directions of the cooling gas inlet or the cooling gas outlet are slanted downward toward the inside of the cooling chamber respectively. 3 . 3. A kind of externally heated coal-based vertical furnace for producing direct reduced iron according to claim 1, characterized in that, the cooling gas inlet and the cooling gas outlet are relatively arranged; that is, the cooling chamber wall on one side of the cooling chamber Cooling gas inlets are provided on the cooling gas passages inside, and cooling gas outlets are provided on the cooling gas passages in the cooling chamber wall on the other side. 4. A kind of externally heated coal-based vertical furnace for producing direct reduced iron according to claim 1, characterized in that cooling gas inlets are provided on the cooling gas passages at the bottom of the cooling chamber walls on both sides of the cooling chamber , cooling gas outlets are provided on the cooling gas passages on the top of the cooling chamber walls on both sides. 5. A kind of externally heated coal-based vertical furnace for producing direct reduced iron according to claim 1, characterized in that, said cooling gas channel, cooling gas inlet and cooling gas outlet are respectively built by refractory bricks into, or composed of stainless steel pipes pierced in refractory bricks. 6. A kind of external heating type coal-based vertical furnace for producing direct reduced iron according to claim 1, characterized in that, the reduction chamber is a single row of reduction chambers, double rows of reduction chambers or three rows of reduction chambers, The upper opening of the reduction chamber is narrower and the lower opening is wider along the width direction, and the width of the lower opening of the reduction chamber is 10mm-200mm wider than that of the upper opening of the reduction chamber; the width of the upper opening of the cooling chamber is the same as that of the lower opening of the reduction chamber. 7. A kind of externally heated coal-based vertical furnace for producing direct reduced iron according to claim 1, characterized in that, the upper regenerator and the lower regenerator form a unit regenerator, each The unit heat storage chamber and the combustion chamber are arranged in one-to-one correspondence.

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