Method for smelting reduction ironmaking by using biomass hydrogen-rich micro powder

Abstract

The invention relates to a method for smelting reduction ironmaking by using biomass hydrogen-rich micro powder, which comprises the following steps: drying biomass by using slag sensible heat of a smelting ironmaking furnace, treating the dried biomass into biomass hydrogen-rich micro powder by using a variable-pressure flash evaporation technology, and spraying the biomass hydrogen-rich micro powder into a smelting reduction furnace through a spray gun, meanwhile, the mineral powder and the coal powder are sprayed into the smelting reduction furnace together, reducing gas such as H2 is sprayed to be combusted to provide heat for the smelting reduction furnace, and oxygen is blown into the position above the smelting reduction furnace. According to the method, biomass resources are treated by fully utilizing existing equipment and the prior art, the current situation that fossil resources depend on can be relieved, the secondary utilization efficiency of the biomass resources is improved, and carbon emission reduction of the non-blast furnace ironmaking process is achieved.

Description

Technical Field

[0001] The embodiments of the present disclosure generally relate to the field of metallurgy, and more specifically, to the field of smelting reduction ironmaking technology, and in particular to a smelting reduction ironmaking method using biomass hydrogen-rich micropowder. Background Art

[0002] Biomass is the fourth largest energy source after coal, oil and natural gas. It is also a renewable green energy source. Due to its wide distribution, rich resources, low content of harmful elements and low pyrolysis temperature, it is used as a heating agent or reducing agent in the ironmaking process. Biomass ironmaking refers to the method of extracting metals using renewable biomass rich in carbon and hydrogen as basic energy and reducing agent. Compared with the traditional method of using coal for smelting, biomass ironmaking has the advantages of biomass being renewable, carbon neutral, having a significant effect on CO2 emission reduction and low price. At the same time, biomass has the same characteristics as coal powder after conversion. For the above reasons, the use of biomass as a fuel in the field of smelting has gradually attracted the attention of steel companies. However, biomass itself has low fixed carbon, low calorific value and low energy density, so it is difficult to give full play to the advantages of biomass when it is directly used in smelting. For this reason, biomass needs to be treated before being used in smelting. The commonly used method is to carbonize the biomass to make it more suitable for the smelting process. Biomass hydrogen-rich micropowder is obtained by dehydrating, deoxygenating, enriching hydrogen and extracting carbon from biomass using pressure swing flash technology on the basis of traditional hydrothermal carbonization. The biomass treated by the above method is more suitable for smelting.

[0003] In the prior art, the coal or natural gas in traditional ironmaking is directly replaced by biomass, but the full utilization of biomass is not fully considered. At the same time, the corresponding ironmaking equipment must be used to ensure the quality of the iron products. Summary of the invention

[0004] The object of the present invention is to provide a method for smelting reduction ironmaking using biomass hydrogen-rich fine powder.

[0005] The specific technical solutions of this application are as follows:

[0006] A method for smelting reduction ironmaking using biomass hydrogen-rich micropowder comprises the following steps:

[0007] (1) using the sensible heat of slag from a molten iron furnace to dry the water-containing biomass to obtain dry biomass;

[0008] (2) subjecting the dried biomass obtained in step (1) to a pressure swing flash process to produce biomass hydrogen-rich micropowder;

[0009] (3) Biomass hydrogen-rich micropowder is sprayed into the smelting reduction furnace through a spray gun, and mineral powder and coal powder are sprayed into the smelting reduction furnace together. The remaining spray gun can selectively spray CO or H2 reducing gas, and combustion provides heat for the smelting reduction furnace. Normal temperature high-purity oxygen can be blown into the smelting reaction furnace from above;

[0010] (4) collecting the high-temperature top gas of the molten reduction furnace, and injecting a large amount of biomass hydrogen-rich micropowder into the gas through a spray gun to convert it into a high-temperature reducing gas rich in CO and H2, which can be used for injection in step (3);

[0011] (5) The reducing gas is sequentially passed through a cyclone dust removal device for deep dust removal, and then introduced into a smelting reduction furnace to participate in smelting reduction ironmaking.

[0012] Furthermore, in step (2), the specific steps of the pressure swing flash evaporation process are: the dried biomass in step (1) is sequentially passed through a first pressure swing flash evaporator and a second pressure swing flash evaporator connected in series, and the pressure is gradually reduced and flashed to obtain the biomass hydrogen-rich micropowder.

[0013] Furthermore, the temperature of the first pressure swing flash evaporator is 220-300°C, the pressure is 2.0-3.0 MPa, and the processing time is 20-40 min; the temperature of the second pressure swing flash evaporator is 120-160°C, the pressure is 1.0-1.6 MPa, and the processing time is 10-30 min.

[0014] Furthermore, in step (1), the sensible heat of the slag is used to dry the water-containing biomass in the pneumatic conveying device, and the pneumatic conveying device is used to input the dried biomass into the first pressure swing flash evaporator.

[0015] Furthermore, in step (2), the mass percentage of particles with a particle size of less than 74 μm in the biomass hydrogen-rich micropowder is greater than 80%.

[0016] Furthermore, in step (1), the moisture content of the dried biomass is less than 8 wt %.

[0017] Furthermore, the biomass includes agricultural waste, forestry waste, livestock manure, and urban solid waste.

[0018] Furthermore, the biomass hydrogen-rich micropowder sprayed in step (3) does not need to be subjected to additional heating treatment.

[0019] Furthermore, the biomass hydrogen-rich powder sprayed in step (3) may be at room temperature.

[0020] Furthermore, in step (3), the injection amount of biomass hydrogen-rich micropowder does not exceed 20% of the mass of the mineral powder.

[0021] Advantages and effects of the present invention: The present invention provides a method for using biomass hydrogen-rich micropowder in a molten iron-making furnace, wherein the biomass is first dried using the sensible heat of the slag in the molten iron-making furnace, and the dried biomass is processed into biomass hydrogen-rich micropowder using a pressure-switching flash evaporation technology, and then the biomass hydrogen-rich micropowder is sprayed into a molten reduction furnace through a spray gun, and at the same time, mineral powder and coal powder are sprayed into the molten reduction furnace together, and H 2 The combustion of reducing gases provides heat for the molten reduction furnace, and oxygen is blown into the top of the molten reduction furnace. The present invention can alleviate the current situation of fossil resource dependence, improve the secondary utilization efficiency of biomass resources, and achieve carbon emission reduction in non-blast furnace ironmaking processes by making full use of existing equipment and existing technologies to process biomass resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention discloses a flow chart of a method for smelting reduction ironmaking using biomass hydrogen-rich powder. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention is clearly and completely described below. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The technical solution of the present invention is further explained and illustrated below in conjunction with specific embodiments.

[0025] Example 1

[0026] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific implementations.

[0027] (1) using the sensible heat of slag in a molten iron furnace at about 1500° C.±50° C. to dry the water-containing biomass to obtain a dry biomass with a moisture content of less than 5 wt %;

[0028] (2) subjecting the dried biomass obtained in step (1) to a pressure swing flash evaporation process, wherein the temperature in the first pressure swing flash evaporator is 260±10°C, the pressure is 2.6±0.1MPa, and the treatment time is 30±5min; the temperature in the second pressure swing flash evaporator is 140±10°C, the pressure is 1.3±0.1MPa, and the treatment time is 15±5min, to obtain biomass hydrogen-rich micropowder with a particle size of less than 74μm accounting for not less than 85%;

[0029] (3) Use 750~1200m 3The dried biomass hydrogen-rich micropowder is sprayed into the molten reduction furnace through a spray gun with nitrogen as the carrier gas. At the same time, the mineral powder and coal powder are sprayed into the molten reduction furnace together. The remaining spray gun can selectively spray CO or H2 reducing gas for combustion to provide heat for the molten reduction furnace. 300003 / h of room temperature high-purity oxygen can be blown in from the top of the molten reaction furnace; the injection amount of biomass hydrogen-rich micropowder is 13% of the mass of the mineral powder.

[0030] (4) collecting the high-temperature top gas of 1000-1700°C from the smelting reduction furnace, and injecting a large amount of biomass hydrogen-rich micropowder into the gas through a spray gun to convert it into a high-temperature reducing gas rich in CO and H2; the gas can be used to provide the high-temperature reducing gas used in step (3)

[0031] (5) The reducing gas is sequentially passed through a cyclone dust removal device for deep dust removal, and then introduced into a smelting reduction furnace to participate in smelting reduction ironmaking.

[0032] Compared with the prior art, the present invention has the following advantages: through technical improvement and optimization, it fully utilizes the existing equipment and existing technology to process biomass resources, reduces the investment cost and energy consumption of biomass resource utilization, and alleviates the current situation of the smelting reduction process being highly dependent on fossil resources, improves the secondary utilization efficiency of biomass resources, and realizes carbon emission reduction in non-blast furnace ironmaking processes. By optimizing the temperature and time steps, the smelting efficiency is greatly improved.

[0033] Although the embodiments disclosed in the present invention are as above, the contents described are only embodiments adopted to facilitate understanding of the present invention and are not intended to limit the present invention. Any technician in the field to which the present invention belongs can make any modifications and changes in the form and details of implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A method for smelting reduction ironmaking using biomass hydrogen-rich fine powder, characterized in that: The following steps are involved: (1) using the sensible heat of slag from a molten iron furnace to dry the water-containing biomass to obtain dry biomass; (2) subjecting the dried biomass obtained in step (1) to a pressure swing flash process to produce biomass hydrogen-rich micropowder; (3) Biomass hydrogen-rich micropowder is sprayed into the smelting reduction furnace through a spray gun, and mineral powder and coal powder are sprayed into the smelting reduction furnace together. The remaining spray gun can selectively spray CO or H2 reducing gas, and combustion provides heat for the smelting reduction furnace. Normal temperature high-purity oxygen can be blown into the smelting reaction furnace from above; (4) collecting the high-temperature top gas of the molten reduction furnace, and injecting a large amount of biomass hydrogen-rich micropowder into the gas through a spray gun to convert it into a high-temperature reducing gas rich in CO and H2, which can be used for injection in step (3); (5) The reducing gas is sequentially passed through a cyclone dust removal device for deep dust removal, and then introduced into a smelting reduction furnace to participate in smelting reduction ironmaking.

2. The method for smelting reduction ironmaking using biomass hydrogen-rich fine powder according to claim 1, characterized in that: In step (2), the specific steps of the pressure swing flash evaporation process are: the dried biomass in step (1) is sequentially passed through a first pressure swing flash evaporator and a second pressure swing flash evaporator connected in series, and the pressure is gradually reduced and flashed to obtain the biomass hydrogen-rich micropowder.

3. The method for smelting reduction ironmaking using biomass hydrogen-rich fine powder as claimed in claim 2, characterized in that: The temperature of the first pressure-swing flash evaporator is 220-300°C, the pressure is 2.0-3.0 MPa, and the processing time is 20-40 min; the temperature of the second pressure-swing flash evaporator is 120-160°C, the pressure is 1.0-1.6 MPa, and the processing time is 10-30 min.

4. The method for smelting reduction ironmaking using biomass hydrogen-rich fine powder according to claim 2 or 3, characterized in that: In step (1), the sensible heat of the slag is used to dry the water-containing biomass in the pneumatic conveying device, and the pneumatic conveying device is used to input the dry biomass into the first pressure swing flash evaporator.

5. The method for smelting reduction ironmaking using biomass hydrogen-rich fine powder as claimed in claim 4, characterized in that: In step (2), the mass percentage of particles with a particle size of less than 74 μm in the biomass hydrogen-rich micropowder is greater than 80%.

6. The method for smelting reduction ironmaking using biomass hydrogen-rich fine powder as claimed in claim 5, characterized in that: In step (1), the moisture content of the dried biomass is less than 8 wt %.

7. The method for smelting reduction ironmaking using biomass hydrogen-rich fine powder as claimed in claim 5, characterized in that: The biomass includes agricultural waste, forestry waste, livestock manure, and urban solid waste.

8. The method for smelting reduction ironmaking using biomass hydrogen-rich fine powder as claimed in claim 7, characterized in that: The biomass hydrogen-rich micropowder sprayed in step (3) does not need to be subjected to additional heating treatment.

9. The method for smelting reduction ironmaking using biomass hydrogen-rich fine powder as claimed in claim 8, characterized in that: The biomass hydrogen-rich powder sprayed in step (3) may be at room temperature.

10. The method for smelting reduction ironmaking using biomass hydrogen-rich fine powder as claimed in claim 8, characterized in that: In step (3), the amount of biomass hydrogen-rich micropowder injected does not exceed 20% of the mass of the mineral powder.

Images