A system and method for preparing iron coke by coupling scrap steel and biomass particles

Abstract

The application discloses a system and a method for preparing iron coke by coupling scrap steel and biomass particles, and the system comprises a biomass raw material unit, a scrap steel raw material unit, a crushing and screening unit, a breaking and screening unit, a washing, drying and storing integrated unit and a coking unit.

Description

Technical Field

[0001] This invention relates to the preparation of iron coke, and more particularly to a system and method for preparing iron coke by coupling waste steel with biomass pellets. Background Technology

[0002] Blast furnace ironmaking contributes 10% of global anthropogenic carbon dioxide emissions. With the continuous development of blast furnace technology, the reduction of carbon consumption and carbon dioxide emissions using traditional ironmaking operations has reached its maximum. Therefore, developing and applying low-carbon smelting technologies has become an inevitable choice for future blast furnace ironmaking. The iron-coke new furnace charge process is one of the new low-carbon blast furnace ironmaking technologies. Current research shows that using iron ore powder and coal powder to prepare iron coke through coking methods can improve smelting efficiency, enhance energy conservation and emission reduction, and reduce the coke ratio in blast furnaces. However, current iron-coke processes utilize existing iron ore and coal resources. To further improve resource recycling and reduce carbon emissions, it is necessary to optimize and improve the selection of raw materials and the supporting process flow.

[0003] In recent years, the amount of scrap steel generated in my country has been increasing year by year. Traditional landfill and stockpiling methods not only waste resources but also potentially cause environmental pollution. Therefore, promoting the recycling of scrap steel can not only alleviate resource pressure but also help reduce environmental pollution and promote the green transformation of the steel industry. If this iron resource, scrap steel, is applied to the production of highly reactive iron coke, which is made from pulverized coal and iron-containing minerals, it can greatly promote the recycling of industrial solid waste.

[0004] Biomass, as a renewable green energy source, possesses the characteristics of "carbon cycle and carbon neutrality." Refining biomass into coke can replace part of the combustion of pulverized coal and iron ore coke, producing reducing gas CO, thereby improving the reduction efficiency of iron ore. However, directly adding biomass-refined coke to the blast furnace presents some problems: biomass has relatively low reactivity, affecting the efficiency of CO production; the ash in biomass contains harmful elements, which accumulate in the blast furnace, affecting the burden and refractory materials, reducing burden performance and damaging the blast furnace wall materials.

[0005] In view of this, it is necessary to design a method for preparing iron coke by coupling waste steel with biomass pellets to solve the above problems. Summary of the Invention

[0006] To achieve the above objectives, the present invention first provides a system for preparing iron coke by coupling scrap steel with biomass pellets. The system includes: a biomass raw material unit, a scrap steel raw material unit, a crushing-screening unit, a crushing-screening unit, an integrated washing, drying and storage unit, and a coking unit.

[0007] Furthermore, the integrated washing, drying, and storage unit includes two side-by-side pickling tanks. Biomass pellets and scrap steel pellets from the crushing-screening unit enter the pickling tanks for pickling. The upper part of the pickling tank is equipped with a feed port, a liquid filling port, and an exhaust port. Two spray pipes are installed inside the pickling tank, located on either side of the tank's symmetrical line. These pipes utilize the high-temperature nitrogen generated during coke quenching to heat and stir the biomass pellets, scrap steel pellets, and washing liquid within the tank. Inside the pickling tank, below the spray pipes, is a rubber conical float. The diameter of the rubber conical float is slightly smaller than the tank's diameter. When no washing liquid is injected into the tank, the rubber conical float rests on the bottom support of the pickling tank. When washing liquid is injected into the tank... Afterwards, the rubber cone-shaped floating plate floats on the pickling tank, while the biomass pellets and scrap steel pellets added through the feed port also fall onto the cone-shaped floating plate. When pickling or washing is completed, the annular outlet around the bottom support of the pickling tank is opened. The washing liquid in the pickling tank, carrying the washed ash, first passes through the gap between the rubber cone-shaped floating plate and the tank body of the pickling tank, and is discharged through the annular outlet. As the washing liquid is discharged, the rubber cone-shaped floating plate also descends until it sits back on the bottom support of the pickling tank. At this time, the descending channel between the biomass pellets and scrap steel pellets on its cone-shaped floating plate and the annular outlet is also opened, so that the washed biomass pellets and scrap steel pellets can be discharged through the annular outlet.

[0008] Furthermore, multiple turbine grooves are provided on the cone of the rubber cone-shaped floating disc.

[0009] Furthermore, the biomass pellets and scrap steel pellets discharged from the pickling tank enter a mixing chamber, where they are mixed and then sent to the coking stage. The pickling tank itself has a volume of 40m³. 3 Height 6.2m.

[0010] Furthermore, the crushing-screening unit includes a scrap steel crusher and a scrap steel particle size screening machine.

[0011] Furthermore, the coking unit includes a carbonization chamber, a coke quenching tower, and an iron and coke crusher.

[0012] Furthermore, the pickling tank's main parameters include a volume of 40m³. 3 Height 6.2m.

[0013] Furthermore, the carbonization chamber has a heating range of 0–1300°C.

[0014] Furthermore, the quenching tower adopts a dry quenching method.

[0015] This invention also provides a method for preparing iron coke using a system for coupling biomass pellets with scrap steel as described above, characterized by the following steps: Biomass raw materials and scrap steel raw materials are respectively loaded into a biomass pulverizer and a scrap steel crusher to obtain biomass pellets and scrap steel pellets, which are then sieved to select pellets of suitable size; the biomass pellets and scrap steel pellets of suitable size are separately loaded into two pickling tanks, and a 3%-5% hydrochloric acid solution is added to the tanks at a solid-liquid ratio of 1:10; a rubber cone-shaped float floats in the pickling tank, and the biomass pellets and scrap steel pellets added through the feed port also fall onto the cone of the rubber cone-shaped float; the solution is heated and stirred using high-temperature nitrogen gas generated during coke quenching; after pickling or water washing is completed... When the annular outlet around the bottom support of the pickling tank is opened, the washing liquid in the pickling tank, carrying the ash washed off, first passes through the gap between the rubber cone-shaped floating plate and the tank body of the pickling tank, and is discharged through the annular outlet. As the washing liquid is discharged, the rubber cone-shaped floating plate also descends until it sits back on the bottom support of the pickling tank. At this time, the descending channel between the biomass pellets and scrap steel pellets on its cone and the annular outlet is also opened. At the same time, high-temperature nitrogen gas is injected into the tank again through the nozzle. While drying the biomass pellets and scrap steel pellets, it is also discharged through the annular outlet. After being mixed in the mixing chamber, it is sent to the carbonization chamber of the coking unit. After carbonization, the coking operation is completed in the quenching tower. Finally, it is sent to the crusher to obtain iron coke of different particle sizes.

[0016] The following will further explain the concept, specific structure, and technical effects of the present invention in conjunction with the accompanying drawings, so as to fully understand the purpose, features, and effects of the present invention. Attached Figure Description

[0017] Figure 1 This is a system flow diagram of preparing iron coke from waste steel coupled with biomass pellets in a preferred embodiment of the present invention.

[0018] Figure 2 This is a schematic diagram of the washing, drying and storage integrated unit in this invention.

[0019] Figure 3 This is a schematic diagram of the material discharge operation of the integrated washing, drying and storage unit in this invention.

[0020] Figure 4 This is a cross-sectional view of the pickling tank in this invention. Detailed Implementation

[0021] The following description, with reference to the accompanying drawings, illustrates several preferred embodiments of the present invention to make its technical content clearer and easier to understand. The present invention can be embodied in many different forms, and the scope of protection of the present invention is not limited to the embodiments mentioned herein.

[0022] The process flow of the method for preparing iron coke by coupling scrap steel with biomass pellets according to the present invention is as follows: Figure 1 As shown, it includes a biomass raw material unit, a scrap steel raw material unit, a crushing-screening unit, a crushing-screening unit, an integrated washing, drying and storage unit, and a coking unit.

[0023] This invention first provides an integrated washing, drying, and storage unit, such as... Figure 2-4 As shown, the unit includes two side-by-side pickling tanks, 100 and 200. Biomass pellets and scrap steel pellets from the crushing-screening unit enter pickling tanks 100 and 200 respectively for pickling.

[0024] The upper part of pickling tanks 100 and 200 is equipped with a feed port 2 and a liquid addition and venting port 3. Two nozzles 4 are installed inside pickling tank 1. The nozzles 4 are located on both sides of the symmetry line of the pickling tank, and are used to heat and stir the biomass particles, scrap steel particles, and washing liquid inside pickling tank 1 using high-temperature nitrogen gas generated from coke quenching. The angle between the nozzles 4 and the wall of pickling tank 1 is 60°-75°, and the deflection angle from the symmetry line of pickling tank 1 is 30°-40°. Inside pickling tank 1, a rubber conical cap float 5 is installed below the nozzles 4. The diameter of the rubber conical cap float 5 is slightly smaller than the diameter of the pickling tank body, and its conical cap is equipped with multiple turbine grooves 10. When no washing solution is injected into the tank, the rubber conical float 5 rests on the bottom support 6 of the pickling tank 1. After the washing solution is injected into the tank, the rubber conical float 5 floats on the pickling tank 1. At the same time, the biomass pellets and scrap steel pellets added through the feed port 2 also fall on the conical cap of the rubber conical float 5 and, under the influence of gravity, suspend in the washing solution. At this time, the high-temperature nitrogen gas injected from the nozzle 4 agitates the washing solution, and at the same time, the turbine groove 10 drives the rubber conical float 5 to rotate, thereby further promoting the agitation of the washing solution in the pickling tank 1. After pickling or water washing is completed, when the annular outlet 8 around the bottom support 6 of the pickling tank 1 is opened, the washing solution in the pickling tank 1, carrying the ash washed off, first passes through the gap 7 between the rubber conical float 5 and the tank body of the pickling tank 1, and is discharged through the annular outlet 8. As the washing liquid is discharged, the rubber cone-shaped floating plate 5 descends until it rests again on the bottom support 6 of the pickling tank 1. At this time, the descending channel 9 between the biomass pellets and scrap steel pellets on its cone and the annular outlet 8 also opens. High-temperature nitrogen gas is then injected into the tank again through the nozzle 4, drying the biomass pellets and scrap steel pellets while simultaneously discharging them through the annular outlet 8. Thus, unlike existing biomass pellet and scrap steel pellet pickling equipment, in the pickling tank 1 of this invention, the washing liquid containing ash is discharged first from below the biomass pellets and scrap steel pellets, preventing ash retention between them. This minimizes the residual ash in the washed biomass pellets and scrap steel pellets. Simultaneously, the high-temperature nitrogen gas, while drying and discharging the washed biomass pellets and scrap steel pellets, further blows away the residual ash between them, laying a good foundation for reducing the ash content of the subsequent coke.

[0025] Biomass pellets and scrap steel pellets discharged from pickling tanks 100 and 200 enter mixing chamber 11, and after being mixed in mixing chamber 11, they are sent to the coking process.

[0026] The system for preparing iron coke from scrap steel coupled with biomass pellets according to the present invention, during operation, firstly, biomass raw materials and scrap steel raw materials are respectively loaded into a biomass pulverizer and a scrap steel crusher to obtain biomass pellets and scrap steel pellets, which are then screened to select pellets of suitable size. The biomass pellets and scrap steel pellets of suitable size are separately loaded into two pickling tanks, and a 3%-5% hydrochloric acid solution is added to the tanks at a solid-liquid ratio of 1:10. A rubber cone-shaped float floats in the pickling tank, and simultaneously, the biomass pellets and scrap steel pellets added through the feed port also fall onto the cone of the rubber cone-shaped float. The solution is heated and stirred using high-temperature nitrogen gas generated during coke quenching. After pickling or water washing is completed, when the annular outlet around the bottom support of the pickling tank is opened, the washing liquid in the pickling tank, carrying the ash removed, first passes between the rubber cone-shaped float and the tank body of the pickling tank. The waste liquid is discharged through the annular outlet. As the washing liquid is discharged, the rubber cone-shaped floating plate also descends until it sits back on the bottom support of the pickling tank. At this time, the descending channel between the biomass pellets and scrap steel pellets on the cone and the annular outlet is opened. At the same time, high-temperature nitrogen gas is injected into the tank again through the nozzle. While drying the biomass pellets and scrap steel pellets, they are discharged through the annular outlet. After being mixed in the mixing chamber, they are sent to the carbonization chamber of the coking unit. After carbonization, the coking operation is completed in the quenching tower. Finally, they are sent to the crusher to obtain iron coke of different particle sizes.

[0027] The preferred embodiments of the present invention have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of the present invention without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of the present invention through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A system for producing iron coke by coupling scrap steel with biomass pellets, characterized in that, The system includes a biomass raw material unit, a scrap steel raw material unit, a crushing-screening unit, a crushing-screening unit, an integrated washing, drying and storage unit, and a coking unit; The integrated washing, drying and storage unit includes two pickling tanks arranged side by side. Biomass pellets from the crushing-screening unit and scrap steel pellets from the crushing-screening unit enter the two pickling tanks for pickling. The pickling tank is provided with a feeding port, a liquid filling port, and an exhaust port at the top. The pickling tank is provided with two spray pipes, which are located on both sides of the symmetry line of the pickling tank. They are used to heat and stir the biomass particles or scrap steel particles and the washing liquid in the pickling tank using the high-temperature nitrogen gas generated by coke quenching. A rubber cone-shaped floating plate is installed inside the pickling tank below the nozzle, and the diameter of the rubber cone-shaped floating plate is slightly smaller than the diameter of the pickling tank body. When no washing liquid is injected into the pickling tank, the rubber cone-shaped floating plate sits on the bottom support of the pickling tank; when washing liquid is injected into the pickling tank, the rubber cone-shaped floating plate floats in the pickling tank, and the biomass pellets or scrap steel pellets added through the feed port fall onto the cone of the rubber cone-shaped floating plate. After pickling or washing is completed, the annular outlet around the bottom support of the pickling tank is opened. The washing liquid in the pickling tank carries the eluted ash through the gap between the rubber cone float and the tank body of the pickling tank, and is discharged through the annular outlet. As the washing liquid is discharged, the rubber cone-shaped floating plate descends and rests on the bottom support again, opening the descending channel between the biomass pellets or scrap steel pellets on the cone and the annular outlet, thereby allowing the washed biomass pellets or scrap steel pellets to be discharged from the annular outlet. The rubber cone-shaped floating disc has multiple turbine grooves on its cone-shaped cap.

2. The system for preparing iron coke by coupling scrap and biomass particles according to claim 1, wherein, Biomass pellets and scrap steel pellets discharged from the two pickling tanks respectively enter the mixing chamber, are mixed, and then sent to the coking unit.

3. The system for preparing iron coke by coupling scrap with biomass pellets according to claim 1, wherein, The crushing-screening unit includes a scrap steel crusher and a scrap steel particle size screening machine.

4. The system for preparing iron coke by coupling scrap and biomass particles according to claim 1, wherein, The coking unit includes a carbonization chamber, a coke quenching tower, and an iron coke crusher.

5. The system for preparing iron coke by coupling scrap steel with biomass pellets as described in claim 1, characterized in that, The pickling tank has a volume of 40 m³ and a height of 6.2 m.

6. The system for preparing iron coke by coupling scrap steel with biomass pellets as described in claim 4, characterized in that, The quenching tower adopts a dry quenching method.

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