CN101724727B - A Short Process Rotary Hearth Furnace Continuous Steelmaking Method Using Energy Comprehensively - Google Patents

Abstract

The invention relates to a short-flow environment-friendly plant for steel production with a rotary hearth furnace continuous steelmaking method and equipment as the cores and with noncoking coal or natural gases as the main energy. Coal dust (natural gases, etc.) and oxygen are jetted into a continuous steelmaking furnace to smelt high temperature pre-reduced metallized pellets provided by the rotary hearth furnace to realize continuous steelmaking, and the molten steel is directly manufactured into the finished products by cast-rolling integration equipment after being refined or is manufactured into the finished products by traditional continuous casting and steel rolling. Meanwhile, the high temperature coal gas generated by a continuous steelmaking furnace is used for the pre-reduced pellets provided by the rotary hearth furnace after being reformed and the other part of high temperature reformed coal gas can be used for traditional continuous casting and steel rolling heating furnaces. The heat of the high temperature waste gas in the rotary hearth furnace is cascade-utilized to preheat the oxygen-enriched air and the pellets for the rotary hearth furnace. The high temperature waste gas in the steel rolling heating furnace is used for preheating the air for the heating furnace. The iron-containing dust is recycled and the steel slag and other dust are used for manufacturing cement. Therefore, the plant has high comprehensive utilization efficiency of energy, low energy consumption, low production cost, less emission and small total investment, and saves land.

Description

A Short Process Rotary Hearth Furnace Continuous Steelmaking Method Using Energy Comprehensively

technical field

The invention relates to a short-flow rotary hearth furnace continuous steelmaking method for steel and steel production, in particular to a complete short-flow industrial steel production method that uses non-coking coal as the main component and comprehensively utilizes energy, and belongs to the technical field of iron and steel metallurgy.

Background technique

With the rapid development of the world's iron and steel industry and the international community's increasing emphasis on environmental protection, energy conservation and emission reduction, and the shortage of resources such as iron ore and coking coal, people are constantly looking for an iron or steelmaking method that does not use coking coal. It is a complete short-process factory method for effective utilization of various iron-containing dusts, effective utilization of secondary energy generated in the process, and reuse of waste heat generated.

At present, steel production mainly has two forms: short process and long process. The traditional long process is from iron ore, sintering (or pelletizing), coking, blast furnace ironmaking, converter blowing into crude molten steel, and then refining furnace steelmaking, and then rolling steel into products. Lack of coking coal resources, huge scale, high investment, large land occupation, long production cycle, high energy consumption per ton of steel, and serious environmental pollution are disadvantages that cannot be overcome by the traditional long process.

The short process is to use scrap steel, direct reduced iron (DRI, sponge iron) as raw materials, melt and oxidize crude steel in an electric furnace, and produce finished steel products through refining, continuous casting, and rolling without coke. The most common method is The MIDREX and HYL methods using natural gas as the reducing agent, and the rotary kiln method, shaft furnace method, and rotary hearth furnace method using coal as the reducing agent. However, the current short process has not achieved the complete short-process factory effect of efficient energy utilization, efficient secondary energy reuse, high-efficiency waste heat utilization, and comprehensive utilization of iron-containing dust from direct ore steelmaking to finished products. High energy consumption and high production costs.

Contents of the invention

Aiming at the deficiencies of the prior art, the invention provides a short-flow rotary hearth furnace continuous steelmaking method for comprehensive utilization of energy, and the invention also provides equipment for the method.

Summary of the invention

The invention uses non-coking coal as the main energy source, takes the continuous steelmaking method and equipment of the rotary hearth furnace as the core, and makes full use of the secondary energy high-temperature gas produced by the continuous steelmaking method and equipment to upgrade it into a rotary hearth furnace or/and steel rolling heating furnace The high-temperature gas of the rotary hearth furnace is used to preheat the rotary hearth furnace with oxygen-enriched air and pellets. The integrated casting and rolling equipment or traditional continuous casting and rolling equipment are used to directly produce qualified steel. Low-pressure water steam or low-temperature water is used for gas reforming after pressurization, iron-containing dust and iron oxide scale are returned to pellets for pelletizing, steel slag and dust are used to make cement, and a complete set of production from iron ore to steel is realized. Ultra-short-flow rotary hearth furnace continuous steelmaking production, according to the method of the present invention, can be built into an environment-friendly factory with less investment, small floor space, low operating cost, low energy consumption, high energy utilization rate, comprehensive utilization of all materials, and low emissions .

The raw materials in the present invention are iron ore powder, iron-containing dedusting ash, iron oxide scale, etc., which are conventional raw materials for continuous steelmaking in a rotary hearth furnace, and are collectively referred to as iron-containing materials in this application.

Since the present invention relates to the production method from the iron ore raw material to the finished steel product, wherein there are many process steps involved, except for the clearly defined process conditions, the process parts not specified in the present invention are all according to the prior art in this field.

Detailed description of the invention

A short-process rotary hearth furnace continuous steelmaking method that comprehensively utilizes energy, including material ball milling, batching, pelletizing, pelletizing shaft furnace preheating, rotary hearth furnace pre-reduction, continuous steelmaking, molten steel refining, continuous casting, and rolling Become a material, the steps are as follows:

1) The iron-containing materials are pelletized and processed into pellets after ball milling and batching.

2) The pellets obtained in step 1) are preheated to 3500-450°C by the 850-950°C exhaust gas discharged from the oxygen-enriched air preheater of the rotary hearth furnace in the preheating device and sent to the rotary hearth furnace.

3) In the rotary hearth furnace, the pellets are burned and heated by high-temperature reformed gas at 800-850°C to obtain pre-reduced metallized pellets with a metallization rate of 85-95% and a furnace temperature of 1000-1200°C for continuous steelmaking At the same time, the high-temperature exhaust gas of 1100℃～1200℃ generated by the rotary hearth furnace is input into the oxygen-enriched air preheater, and the oxygen-enriched air is preheated in the oxygen-enriched air preheater to 600～700℃ for the rotary hearth furnace to burn at high temperature Use of upgraded gas;

4) Put the pre-reduced metallized pellets provided by the rotary hearth furnace into the continuous steelmaking furnace, inject carbonaceous materials and oxygen to carry out continuous steelmaking; The high-temperature reformed gas is used for the rotary hearth furnace or/and steel rolling heating furnace;

5) The molten steel with a C content of 0.01-0.40wt% and a temperature of 1580-1680°C produced in a continuous steelmaking furnace is supplied to the LF refining furnace or RH refining furnace after preliminary deoxidation and alloying, and the molten steel produced in the refining furnace is cast and rolled into steel products .

The temperature at which the pre-reduced metallized pellets in step 4) are loaded into the continuous steelmaking furnace is 900-1100°C.

The high-temperature reformed coal gas is to pass the 1450-1550°C high-temperature gas produced by the continuous steelmaking furnace through the suspended coal powder in the coal gas reforming furnace, and _CO2 reacts with the coal powder to produce CO and absorb heat at the same time; water vapor and Pulverized coal reacts to generate _H2 and CO, and absorb heat at the same time; the content of _CO2 in the upgraded gas is less than 15%, the content of water vapor is less than 5.0%, and the temperature is 800-850℃, which is directly supplied to the rotary hearth furnace or/and steel rolling heating furnace use.

The _CO2 content in the high-temperature gas is 29-31% by volume, and the water vapor content is 11-13% by volume. The remaining components in the high-temperature gas are CO, H ₂ , CH ₄ and N ₂ , and their content ranges are well known to those skilled in the art.

The iron-containing dust and iron oxide scale produced in the production process are reused as raw materials in step 1),

Steel slag and other dust generated during the production process are used as admixtures to make cement.

The low-pressure steam or low-temperature water generated during the production process is used for high-temperature gas upgrading.

In step 1), the discharge temperature of the shaft furnace exhaust gas is controlled not to be higher than 150°C.

Preferably, the pellets in step 1) are Φ8-28mm round pellets prepared by a pelletizing disc, or briquettes prepared by a pelletizing machine. Coal powder, binder and conventional auxiliary materials for pelletizing should be added to iron-containing materials during pelletizing.

Preferably, the iron-containing material in step 1) is ball-milled to a fine powder of 50-200 μm for pelletizing.

Preferably, the carbonaceous material in step 2) is selected from non-coking coal powder, natural gas or combustible ice. Combustible ice is natural gas hydrate, which is a white solid crystal formed during the interaction between gas or volatile liquid and water under certain conditions (suitable temperature, pressure, gas saturation, water salinity, pH value, etc.) A substance that looks like ice.

The continuous steelmaking furnace described in step 2) can control the coal-oxygen ratio by adjusting the injection amount of carbon-containing materials and oxygen injection, and then control the production of high-temperature gas to meet the needs of other processes. It can be carried out according to conventional processes, preferably using the methods and equipment described in patent applications 200810238696.6, 200810249806.9, 200810139695.6, 200810139696.0 and 200810140082.4.

Step 2) The oxygen-enriched air preheater for preheating oxygen-enriched air can be a tube heat exchanger, or other forms of high-efficiency heat exchangers.

The special equipment for continuous steelmaking in a short-flow rotary hearth furnace for comprehensive utilization of energy in the present invention includes a ball mill (2), a batching bin (3), pelletizing equipment (4), a pellet preheating device, and a rotary hearth furnace (6 ), oxygen-enriched air preheater (7), coal injection tower (8) or combustible gas reserve cabinet (23), continuous steelmaking furnace (9), oxygen production equipment (10), gas reforming equipment (11), Refining furnace (12), casting and rolling equipment, dust removal equipment (19). It is characterized in that the ball mill (2), pelletizing equipment (4), pellet preheating device, rotary hearth furnace (6), continuous steelmaking furnace (9), refining furnace (12) and casting and rolling equipment are connected in sequence, spraying The coal tower (8) is connected with the continuous steelmaking furnace (9) for supplying non-coking coal pulverized coal to the continuous steelmaking furnace (9), and the oxygen making equipment (10) is connected with the continuous steelmaking furnace (9) for supplying The continuous steelmaking furnace (9) provides oxygen; the gas reforming equipment (11) is used to modify the gas produced by the continuous steelmaking furnace (9); the modified gas produced by the gas reforming equipment (11) is transported to the rotary bottom The furnace (6); the dedusting equipment (19) is connected with the rotary hearth furnace (6), and is used for dedusting the waste gas produced by the rotary hearth furnace (6).

Preferably, the ball mill (2) is connected with the pelletizing equipment (4) via the batching bin (3).

Preferably, the dust generated by the dust removal equipment is discharged through the chimney (18).

Preferably, a steel slag processing device (20) is also included, the steel slag processing device (20) is connected with the continuous steelmaking furnace (9), and is used for processing the steel slag produced by the continuous steelmaking furnace (9).

The above-mentioned pellet preheating device is a shaft furnace (5), or a grate type preheating furnace.

Above-mentioned coal injection tower (8) is replaced by gas reserve cabinet (23).

The above-mentioned oxygen generating equipment can adopt pressure swing adsorption technology equipment (oxygen used in production plants), or cryogenic technology equipment (oxygen and argon used in production plants).

The casting and rolling equipment is mainly composed of a continuous casting machine (13), a steel rolling heating furnace (14), a steel rolling equipment (15), and a heating furnace air preheater (17). As shown in Figure 1.

The above casting and rolling equipment may also be integrated casting and rolling equipment (22). as shown in picture 2. The integrated casting and rolling equipment is selected from integrated casting and rolling equipment for steel strips, integrated casting and rolling equipment for section steel, or integrated casting and rolling equipment for bars.

The steel products produced by using the method and equipment of the present invention can be steel plates, steel strips, section steels or rods.

The specific process route of the present invention to continuously obtain molten steel from iron-containing materials such as iron ore is: use non-coking coal as the main energy source, take the rotary hearth furnace and continuous steelmaking equipment as the core, and realize the secondary energy reutilization and waste gas produced by the process itself. Cascade utilization of heat, full utilization of physical heat, efficient utilization of energy and resources such as iron-containing dust recycling, ultra-short process flow for producing qualified steel, and energy-saving and environmentally friendly factories for steel slag and other dust to manufacture cement. The factory has achieved high comprehensive utilization efficiency of energy, low energy consumption, low production cost, low emissions, low total investment, and land saving. revolutionary change.

Technical characteristics of the present invention and good effect are as follows:

The present invention consists of a raw material field, a ball mill, pelletizing equipment, a shaft furnace or a grate type preheating furnace, a rotary hearth furnace, an oxygen-enriched air preheater, a continuous steelmaking furnace, oxygen making equipment, gas reforming equipment, a refining furnace, The short-process steel production plant composed of integrated casting and rolling equipment or traditional continuous casting and rolling equipment as the main equipment produces qualified steel; the steel produced can be steel plate, steel strip, section steel or bar.

(1) The present invention takes the rotary hearth furnace and continuous steelmaking equipment as the core to produce steel. Compared with the traditional long process, coking, sintering, blast furnace, and converter equipment are not required, and full continuous steelmaking is realized. It is integrated with casting and rolling equipment Combination is the currently known process from ore to steel with the lowest energy consumption, the least dispatch and the shortest process flow, and it is a revolutionary process change in iron and steel metallurgy.

(2) The present invention also adopts traditional continuous casting and steel rolling equipment to replace integrated casting and rolling equipment to produce steel products with various quality requirements.

(3) The present invention achieves the goals of using non-coking coal as the main energy source, taking the rotary hearth furnace and continuous steelmaking equipment as the core, reusing the secondary energy generated, cascading utilization of waste gas heat, and fully utilizing physical heat. When the integrated equipment produces steel, the comprehensive energy consumption per ton of steel reaches 551 kg of standard coal. When using traditional continuous casting, billet hot delivery and hot charging, heating furnace, and steel rolling equipment to produce steel, the comprehensive energy consumption per ton of steel reaches 585 kg of standard coal. It is the process with the highest energy utilization rate and the lowest energy consumption among the known iron and steel processes.

(4) The present invention realizes the recycling of iron-containing dust, and the production of environmentally friendly steel products in which steel slag and other dust are used to manufacture cement, and the emission reduction effect is remarkable.

(5) The present invention has low energy consumption, low production cost, less emissions, less total investment, land and water conservation, is the most effective factory process for energy conservation and emission reduction, and has strong market competitiveness.

Description of drawings

Fig. 1 is a schematic flow chart of the present invention. Among them: 1 raw material field, 2 ball mill, 3 batching warehouse, 4 pelletizing equipment, 5 shaft furnace, 6 rotary hearth furnace, 7 oxygen-enriched air preheater, 8 coal injection tower, 9 continuous steelmaking furnace, 10 oxygen making equipment , 11 gas upgrading equipment, 12 refining furnace, 13 traditional continuous casting machine, 14 steel rolling heating furnace, 15 steel rolling equipment, 16 steel products, 17 heating furnace air preheater, 18 chimney, 19 dust removal equipment, 20 steel slag treatment, 21 cement factory.

Fig. 2 is a schematic flow chart of another casting and rolling process of the present invention. Among them, 22 integrated casting and rolling equipment, the integrated casting and rolling equipment replaces the traditional continuous casting, steel rolling heating furnace and steel rolling equipment, others are the same as in Figure 1.

Fig. 3 is another schematic flow chart of the present invention. The combustible gas reserve cabinet (23) has replaced the coal injection tower (8), and the non-coking coal pulverized coal is replaced by natural gas, and others are with Fig. 2.

Detailed ways

The following examples are further illustrations of the present invention, but the present invention is not limited thereto.

Example 1:

Raw materials: Iron-containing materials include: iron ore powder, iron-containing dust, iron scale; carbon-containing materials are selected from coal powder; other raw materials include lime, fluorite, and dolomite.

The equipment of the factory of the present invention includes: raw material field 1, ball mill 2, batching bin 3, pelletizing equipment 4, shaft furnace 5, rotary hearth furnace 6, oxygen-enriched air preheater 7, coal injection tower 8, continuous steelmaking furnace 9. Oxygen production equipment 10, gas upgrading equipment 11, refining furnace 12, traditional continuous casting machine 13, steel rolling heating furnace 14, steel rolling equipment 15, steel products 16, heating furnace air preheater 17, chimney 18, dust removal equipment 19 , Steel slag treatment 20, cement plant 21. As shown in Figure 1.

Ball mill 2, ball making equipment 4, shaft furnace 5, rotary hearth furnace 6, continuous steelmaking furnace 9, refining furnace 12 and casting and rolling equipment are connected in sequence, and casting and rolling equipment is mainly composed of continuous casting machine 13, steel rolling heating furnace 14, steel rolling equipment 15. The heating furnace air preheater 17 is composed in turn; the coal injection tower 8 is connected with the continuous steelmaking furnace 9, and is used to provide non-coking coal coal powder to the continuous steelmaking furnace 9, and the oxygen making equipment 10 is connected with the continuous steelmaking furnace 9, It is used to provide oxygen to the continuous steelmaking furnace 9; the gas reforming equipment 11 is used to modify the gas produced by the continuous steelmaking furnace 9; the modified gas produced by the gas reforming equipment 11 is transported to the rotary hearth furnace 6; dust removal equipment 19 is connected with the rotary hearth furnace 6, and is used for dedusting the waste gas produced by the rotary hearth furnace 6. It also includes a steel slag processing device 20 connected to the continuous steelmaking furnace 9 for processing steel slag produced by the continuous steelmaking furnace 9 .

The ball mill 2 is connected with the pelletizing equipment 4 through the batching bin 3 .

The dust generated by the dust removal equipment is discharged through the chimney 18.

The preheating pellet shaft furnace 5 can be replaced with a grate type preheating furnace or other more efficient pellet preheating equipment.

Raw material field 1 iron ore powder or/and iron-containing dust, iron oxide scale and other iron-containing materials are finely ground by ball mill 2 to the required particle size and then sent to batching bin 3, and the raw pellets produced by pelletizing equipment 4 are sent to shaft furnace 5 for preheating , and then sent to the rotary hearth furnace 6 for pre-reduction, the metallized pellets after the pre-reduction are sent to the continuous steelmaking furnace 9 to smelt qualified molten steel, and the molten steel enters the refining furnace 12 for refining after preliminary alloying, and the refined molten steel is produced by a traditional continuous casting machine 13 cast slabs, after being heated by the steel rolling heating furnace 14, the qualified steel products 16 are rolled by the steel rolling equipment 15 .

The oxygen produced by the non-coking coal through the coal injection tower 8 and the oxygen production equipment 10 is sprayed into the continuous steelmaking furnace 9 with a coal oxygen lance, and the gas (1450-1550°C) produced by the continuous steelmaking furnace 9 is produced by the gas reforming equipment 11 to produce a temperature The high temperature gas of 800～850℃ is supplied to the rotary hearth furnace, or/and the steel rolling heating furnace, and the high temperature of the gas is utilized most efficiently. The low-pressure steam or low-temperature water produced by the factory is used for gas upgrading, and the low-quality heat energy is effectively utilized;

The rotary hearth furnace 6 uses the high temperature exhaust gas generated by itself at 1100°C-1200°C to heat the oxygen-enriched air to 600-700°C through the oxygen-enriched air preheater 7 for high-temperature reforming sent by the rotary hearth furnace 6 and the gas reforming equipment 11 Coal gas (800-850°C) is burned to heat the pre-reduced pellets, and the pre-reduced metallized pellets with a metallization rate of 85-95% and a furnace temperature of 1000-1200°C are directly supplied to the continuous steelmaking furnace; at the same time, oxygen-enriched air is preheated The 850-950°C waste gas discharged from the device 7 is supplied to the rotary hearth furnace through the vertical 5 preheating the pellets to 350-450°C. The final waste gas of the shaft furnace 5 is discharged from the chimney 18 after being dedusted by the dust removal device 19, and the discharge temperature is less than 150°C. The heat of high-temperature exhaust gas is efficiently and fully utilized in cascade.

The steel rolling heating furnace 14 uses the high-temperature exhaust gas with its own tail smoke at 700°C-900°C to heat the air to 400-500°C through the heating furnace air preheater 17 to supply the high-temperature reformed gas ( 800-850° C.) to burn and heat the continuous casting billets for the steel rolling equipment 15 to produce steel products 16 . The exhaust gas at 200-260°C discharged from the air preheater 17 of the heating furnace is discharged from the chimney 18, and the heat of the high-temperature exhaust gas has been fully utilized.

The iron-containing dedusting ash and rolled steel oxide scale produced by the factory are returned to the raw material yard 1 for reuse, and the steel slag is sent to the cement factory 21 to make cement after the steel slag treatment 20 and other dust, and the solid waste has been fully utilized.

The comprehensive consumption of standard coal per ton of steel in the factory is 585Kg standard coal, which is lower than the current long-process iron and steel process average of 620Kg standard coal per ton, and is also lower than that of COREX, FINEX, AUSIRON, HISMELT, DIOS, ROMELT, CCF, AISI, CLEANMELT, etc. Reduction process 900Kg index. The HISMELT process has been developed maturely, and the comprehensive consumption of standard coal per ton of iron is 750Kg.

Example 2:

Raw materials: Iron-containing materials include: iron ore powder, iron-containing dust, iron scale; carbon-containing materials are selected from coal powder; other raw materials include lime, fluorite, and dolomite.

The equipment of the factory of the present invention includes: raw material field 1, ball mill 2, batching bin 3, pelletizing equipment 4, shaft furnace 5, rotary hearth furnace 6, oxygen-enriched air preheater 7, coal injection tower 8, continuous steelmaking furnace 9. Oxygen production equipment 10, gas upgrading equipment 11, refining furnace 12, integrated casting and rolling equipment 22, steel products 16, chimney 18, dust removal equipment 19, steel slag treatment 20, and cement plant 21. as shown in picture 2. Ball mill 2, pelletizing equipment 4, shaft furnace 5, rotary hearth furnace 6, continuous steelmaking furnace 9, refining furnace 12 and integrated casting and rolling equipment 22 are connected in sequence, and coal injection tower 8 is connected with continuous steelmaking furnace 9 for Provide non-coking coal pulverized coal to the continuous steelmaking furnace 9, the oxygen making equipment 10 is connected with the continuous steelmaking furnace 9, and is used to provide oxygen to the continuous steelmaking furnace 9; The gas is reformed; the modified gas produced by the gas reforming equipment 11 is transported to the rotary hearth furnace 6; It also includes a steel slag processing device 20 connected to the continuous steelmaking furnace 9 for processing steel slag produced by the continuous steelmaking furnace 9 .

The ball mill 2 is connected with the pelletizing equipment 4 through the batching bin 3 .

The dust generated by the dust removal equipment is discharged through the chimney 18.

The preheating pellet shaft furnace 5 can be replaced with a grate type preheating furnace or other more efficient pellet preheating equipment.

Raw material field 1 iron ore powder or/and iron-containing dust, iron oxide scale and other iron-containing materials are finely ground by ball mill 2 to the required particle size and then sent to batching bin 3, and the raw pellets produced by pelletizing equipment 4 are sent to shaft furnace 5 for preheating , and then sent to the rotary hearth furnace 6 for pre-reduction, the pre-reduced metallized pellets are sent to the continuous steelmaking furnace 9 to smelt qualified molten steel, and the molten steel is refined in the refining furnace 12 after preliminary alloying, and the refined molten steel is produced by the integrated casting and rolling equipment 22 produces steel products 16 directly.

The oxygen produced by the non-coking coal through the coal injection tower 8 and the oxygen production equipment 10 is sprayed into the continuous steelmaking furnace 9 with a coal oxygen lance, and the gas (1450-1550°C) produced by the continuous steelmaking furnace 9 is produced by the gas reforming equipment 11 to produce a temperature The high temperature gas of 800～850℃ is supplied to the rotary hearth furnace, and the high temperature of the gas is utilized most efficiently. The low-pressure steam or low-temperature water produced by the factory is used for gas upgrading, and the low-quality heat energy is effectively utilized;

The rotary hearth furnace 6 uses the high temperature exhaust gas generated by itself at 1100°C-1200°C to heat the oxygen-enriched air to 600-700°C through the oxygen-enriched air preheater 7 for high-temperature reforming sent by the rotary hearth furnace 6 and the gas reforming equipment 11 Coal gas (800-850°C) is burned to heat the pre-reduced pellets, and the pre-reduced metallized pellets with a metallization rate of 85-95% and a furnace temperature of 1000-1200°C are directly supplied to the continuous steelmaking furnace; at the same time, oxygen-enriched air is preheated The 850-950°C waste gas discharged from the shaft furnace 7 is preheated to 350-450°C through the shaft furnace 5 and supplied to the rotary hearth furnace. The heat of high-temperature exhaust gas is efficiently and fully utilized in cascade.

The iron-containing dedusting ash and rolled steel oxide scale produced by the factory are returned to the raw material yard 1 for reuse, and the steel slag is sent to the cement factory 21 to make cement after the steel slag treatment 20 and other dust, and the solid waste has been fully utilized.

The comprehensive consumption of standard coal per ton of steel in the plant is 551Kg, which is currently known as the steel production process with the lowest comprehensive energy consumption, the least emissions, and the lowest production cost among steel plants.

Example 3:

Raw materials: Iron-containing materials include: iron ore powder, iron-containing dust, iron scale; carbon-containing materials are selected from natural gas; other raw materials include lime, fluorite, and dolomite.

The equipment of the factory of the present invention comprises: raw material field 1, ball mill 2, batching bin 3, pelletizing equipment 4, shaft furnace 5, rotary hearth furnace 6, oxygen-enriched air preheater 7, continuous steelmaking furnace 9, oxygen making equipment 10. Gas reforming equipment 11, refining furnace 12, integrated casting and rolling equipment 22, steel products 16, chimney 18, dust removal equipment 19, steel slag treatment 20, cement plant 21, combustible gas storage cabinet 23. As shown in Figure 3. The ball mill 2, the pelletizing equipment 4, the shaft furnace 5, the rotary hearth furnace 6, the continuous steelmaking furnace 9, the refining furnace 12 and the integrated casting and rolling equipment 22 are connected in sequence, and the combustible gas reserve cabinet 23 is connected with the continuous steelmaking furnace 9, To provide natural gas or other combustible gases to the continuous steelmaking furnace 9, the oxygen making equipment 10 is connected with the continuous steelmaking furnace 9, and is used to provide oxygen to the continuous steelmaking furnace 9; The generated gas is reformed; the reformed gas produced by the gas reforming equipment 11 is transported to the rotary hearth furnace 6; It also includes a steel slag processing device 20 connected to the continuous steelmaking furnace 9 for processing steel slag produced by the continuous steelmaking furnace 9 .

The ball mill 2 is connected with the pelletizing equipment 4 through the batching bin 3 .

The dust generated by the dust removal equipment is discharged through the chimney 18.

The preheating pellet shaft furnace 5 can be replaced with a grate type preheating furnace or other more efficient pellet preheating equipment. Natural gas can also be other combustible gases such as combustible ice.

Raw material field 1 iron ore powder or/and iron-containing dust, iron oxide scale and other iron-containing materials are finely ground by ball mill 2 to the required particle size and then sent to batching bin 3, and the raw pellets produced by pelletizing equipment 4 are sent to shaft furnace 5 for preheating , and then sent to the rotary hearth furnace 6 for pre-reduction, the pre-reduced metallized pellets are sent to the continuous steelmaking furnace 9 to smelt qualified molten steel, and the molten steel is refined in the refining furnace 12 after preliminary alloying, and the refined molten steel is produced by the integrated casting and rolling equipment 22 produces steel products 16 directly.

Oxygen and natural gas produced by the oxygen plant 10 are sprayed into the continuous steelmaking furnace 9 respectively, and the coal gas (1450-1550°C) produced by the continuous steelmaking furnace 9 is passed through the gas reforming equipment 11 to produce high-temperature reformed gas at a temperature of 800-850°C Mixed with natural gas for rotary hearth furnace. The high temperature of the coal gas in the continuous steelmaking furnace 9 has been used most efficiently, and the low-pressure steam or low-temperature water produced by the factory is used for gas upgrading, and the low-quality heat energy is effectively utilized;

The rotary hearth furnace 6 uses the high temperature exhaust gas generated by itself at 1100°C-1200°C to heat the oxygen-enriched air to 600-700°C through the oxygen-enriched air preheater 7 for high-temperature reforming sent by the rotary hearth furnace 6 and the gas reforming equipment 11 Coal gas (800-850°C) is burned to heat the pre-reduced pellets, and the pre-reduced metallized pellets with a metallization rate of 85-95% and a furnace temperature of 1000-1100°C are directly supplied to the continuous steelmaking furnace; at the same time, oxygen-enriched air is preheated The 850-950°C waste gas discharged from the shaft furnace 7 is preheated to 350-450°C through the shaft furnace 5 and supplied to the rotary hearth furnace. The heat of high-temperature exhaust gas is efficiently and fully utilized in cascade.

The iron-containing dedusting ash and rolled steel oxide scale produced by the factory are returned to the raw material yard 1 for reuse, and the steel slag is sent to the cement factory 21 to make cement after the steel slag treatment 20 and other dust, and the solid waste has been fully utilized.

The plant consumes 485Nm ³ of natural gas per ton of steel and 555Kg of standard coal. This process is currently known as one of the steel production plants with the least equipment, the least land occupation, the least investment, the shortest process, the least energy consumption, and the lowest cost.

Claims (11)

1. A short-process rotary hearth furnace continuous steelmaking method of comprehensive utilization of energy, including material ball milling, batching, pelletizing, pelletizing shaft furnace preheating, rotary hearth furnace pre-reduction, continuous steelmaking, molten steel refining, continuous casting, Rolling into lumber, the steps are as follows: 1) Iron-containing materials are processed into pellets after ball milling and batching, 2) The pellets obtained in step 1) are preheated to 350-450°C by the 850-950°C exhaust gas discharged from the oxygen-enriched air preheater of the rotary hearth furnace in the preheating device for the rotary hearth furnace, 3) In the rotary hearth furnace, the pellets are burned and heated by high-temperature reformed gas at 800-850°C to obtain pre-reduced metallized pellets with a metallization rate of 85-95% and a furnace temperature of 1000-1200°C for continuous steelmaking At the same time, the high-temperature exhaust gas of 1100℃～1200℃ generated by the rotary hearth furnace is input into the oxygen-enriched air preheater, and the oxygen-enriched air is preheated in the oxygen-enriched air preheater to 600～700℃ for the rotary hearth furnace to burn at high temperature Use of upgraded gas; 4) Put the pre-reduced metallized pellets provided by the rotary hearth furnace into the continuous steelmaking furnace, inject carbonaceous materials and oxygen to carry out continuous steelmaking; The high-temperature reformed gas is used for the rotary hearth furnace or/and steel rolling heating furnace; 5) The molten steel with a C content of 0.01-0.40wt% and a temperature of 1580-1680°C produced in a continuous steelmaking furnace is supplied to the LF refining furnace or RH refining furnace after preliminary deoxidation and alloying, and the molten steel produced in the refining furnace is cast and rolled into steel products . 2. the short flow rotary hearth furnace continuous steelmaking method of comprehensive utilization of energy as claimed in claim 1, is characterized in that, the temperature that the described pre-reduction metallization pellet of step 4) packs into continuous steelmaking furnace is 900～ 1100°C. 3. The short-flow rotary hearth furnace continuous steelmaking method for comprehensive utilization of energy as claimed in claim 1, characterized in that, the high-temperature reformed gas is made by passing the 1450-1550°C high-temperature gas produced by the continuous steelmaking furnace Coal powder suspended in the gas reforming furnace, CO ₂ reacts with coal powder to produce CO, absorbing heat at the same time; water vapor reacts with coal powder to generate H ₂ and CO, absorbing heat at the same time; the content of CO ₂ in the reformed gas is less than 15%, the water vapor content is less than 5.0%, and the temperature is 800-850°C, which is directly used for rotary hearth furnace or/and steel rolling heating furnace. 4. The short-flow rotary hearth furnace continuous steelmaking method for comprehensive utilization of energy as claimed in claim 1, characterized in that the pellets in step 1) are Ф8-28mm round pellets prepared by a pelletizing disc, or Briquettes prepared by a briquetting machine. 5 . The short-flow rotary hearth furnace continuous steelmaking method for comprehensive utilization of energy according to claim 1 , characterized in that the iron-containing material in step 1) is ball-milled to a fine powder of 50-200 μm for pelletizing. 6 . 6. The short-flow rotary hearth furnace continuous steelmaking method of comprehensive utilization of energy as claimed in claim 1, wherein the carbonaceous material in step 4) is selected from non-coking coal powder, natural gas or combustible ice; The continuous steelmaking furnace described in step 4) can control the ratio of coal to oxygen by adjusting the injection amount of carbonaceous material and oxygen injection. 7. A special equipment for continuous steelmaking in a short-flow rotary hearth furnace that comprehensively utilizes energy, including a ball mill (2), a batching bin (3), pelletizing equipment (4), a pellet preheating device, and a rotary hearth furnace (6 ), oxygen-enriched air preheater (7), coal injection tower (8) or combustible gas reserve cabinet (23), continuous steelmaking furnace (9), oxygen production equipment (10), gas reforming equipment (11), Refining furnace (12), casting and rolling equipment, dust removal equipment (19); it is characterized in that ball mill (2), pelletizing equipment (4), pellet preheating device, rotary hearth furnace (6), continuous steelmaking furnace ( 9), the refining furnace (12) is connected to the casting and rolling equipment in sequence, and the coal injection tower (8) is connected to the continuous steelmaking furnace (9), which is used to provide non-coking coal pulverized coal to the continuous steelmaking furnace (9), and the oxygen production equipment (10) link to each other with continuous steelmaking furnace (9), be used for supplying oxygen to continuous steelmaking furnace (9); Coal gas reforming equipment (11) is used for the coal gas that continuous steelmaking furnace (9) produces; The modified gas produced by the gas reforming equipment (11) is transported to the rotary hearth furnace (6); the dust removal equipment (19) is connected with the rotary hearth furnace (6), and is used for dedusting the waste gas produced by the rotary hearth furnace (6). 8. The special equipment for the short-flow rotary hearth furnace continuous steelmaking of comprehensive utilization of energy according to claim 7 is characterized in that the ball mill (2) is connected with the pelletizing equipment (4) through the batching bin (3); the dust removal equipment produces Smoke dust discharges through chimney (18). 9. The special equipment for continuous steelmaking with a short-flow rotary hearth furnace for comprehensive utilization of energy according to claim 7, characterized in that the above-mentioned pellet preheating device is a shaft furnace (5) or a grate type preheating furnace. 10. The special equipment for continuous steelmaking in the short-flow rotary hearth furnace of comprehensive utilization of energy according to claim 7, characterized in that, the above-mentioned casting and rolling equipment mainly consists of continuous casting machine (13), steel rolling heating furnace (14), steel rolling equipment (15), heating furnace air preheater (17) is formed. 11. The special equipment for continuous steelmaking in a short-flow rotary hearth furnace for comprehensive utilization of energy according to claim 7, characterized in that, the above-mentioned casting-rolling equipment is selected from integrated casting-rolling equipment (22); the integrated casting-rolling equipment is selected from Self-steel strip casting and rolling integrated equipment, section steel casting and rolling integrated equipment or bar casting and rolling integrated equipment.

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