Low-carbon collaborative treatment melting furnace for steel dust and organic solid waste

Abstract

The application provides a steel dust and organic solid waste low-carbon synergic treatment melting furnace, which comprises a feeding unit, an iron bath pyrolysis unit and a recovery unit which are sequentially communicated; the iron bath pyrolysis unit comprises a furnace body containing molten iron and an oxygen delivery assembly communicated with an upper cavity in the furnace body; the feeding unit comprises a steel dust injection assembly, an organic solid waste injection assembly and an organic solid waste feeding opening arranged on the top of the furnace body and communicated with the furnace body; and the recovery unit comprises a flue gas recovery assembly communicated with an exhaust opening arranged on the shoulder of the furnace body. Through the above manner, the melting furnace can not only treat different types of organic solid waste and improve the utilization efficiency, but also treat the steel dust by using the organic solid waste, so that molten iron, dust rich in volatile metal elements and high-calorific-value synthetic gas rich in CO and H2 are produced, the reaction rate is fast, the product quality is high, and the efficient resource utilization of the organic solid waste and the steel dust is realized.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to a low-carbon co-processing melting furnace for steel dust and organic solid waste. Background Technology

[0002] The steel production process generates a large amount of steel dust. Currently, the main method for treating this dust is extensive recycling, primarily returning it to the sintering process. However, this method negatively impacts the smooth operation of the blast furnace. To more effectively treat steel dust, various processes have been developed, including rotary kiln, rotary hearth furnace, OxyCup, and DK processes. While these processes can recover steel dust to some extent, they all have certain shortcomings. The rotary kiln process has high requirements for raw materials, high energy consumption, a tendency to form rings, difficulty in stabilizing production, and limited processing capacity. The rotary hearth furnace process mainly produces metallized pellets, but the product has a high sulfur content, low production efficiency, high investment, and a large footprint. The OxyCup process produces molten iron and can handle a wide range of steel dust, but the equipment has a short operating cycle and requires significant maintenance. The DK process is simple to operate and relatively mature, producing molten iron, but requires sintering, resulting in high pollution and high energy consumption.

[0003] Besides steel dust, organic solid waste is another common type of solid waste. Most organic solid waste is combustible and rich in elements such as C, H, and O, possessing a certain amount of chemical energy. Through appropriate treatment, the heat in organic solid waste can be effectively recovered. Furthermore, the pyrolysis and gasification processes of organic solid waste produce large amounts of high-quality reducing gases such as CO and H2, providing excellent reducing media for the development of direct reduction and green ironmaking technologies in my country's steel industry. This is of great significance for the low-carbon and green development of my country's steel industry. Therefore, the research and development of organic solid waste gasification processes and technologies is not only conducive to the efficient resource-based treatment of organic solid waste but also helps promote energy conservation and carbon reduction in the steel industry, which is of great significance.

[0004] Patent CN113151675A discloses a process for the co-sintering and pelletizing of solid waste. This process involves pyrolysis and / or incineration of organic solid waste and steel dust to obtain solid waste residue. The residue is then screened, with coarse-particle residue mixed with sintering raw materials and transported to the sintering process, and fine-particle residue mixed with pelletizing raw materials and transported to the pelletizing process. This provides a new approach for the full-process treatment of multiple solid wastes and eliminates the environmental impact and secondary pollution risks of solid waste while ensuring the quality of sintered ore and pellets. However, although this process can treat both organic solid waste and steel dust simultaneously, it cannot fully utilize the synergistic effect between them, resulting in low treatment efficiency. Furthermore, the incineration and / or pyrolysis processes are carried out in a rotary kiln, making the overall process complex and energy-intensive. How to efficiently and fully recover and utilize the valuable elements and thermal energy of steel dust and organic solid waste while ensuring environmental friendliness remains a pressing issue.

[0005] In view of this, it is necessary to design an improved low-carbon co-treatment device for steel dust and organic solid waste to solve the above problems. Summary of the Invention

[0006] To address the shortcomings of the existing technology, the present invention aims to provide a low-carbon co-processing smelting furnace for steel dust and organic solid waste. By separately setting organic solid waste spray guns and organic solid waste feeding ports, different types of organic solid waste can be treated in a targeted manner, improving their utilization efficiency. Furthermore, by spraying organic solid waste and steel dust into a smelting furnace containing molten iron, pyrolysis and reduction are carried out under iron bath conditions, and the products are efficiently recovered. This effectively co-processes organic solid waste and steel dust, producing molten iron, dust rich in volatile metal elements, and high-calorific-value syngas rich in CO and H2 during the rapid reaction, achieving efficient resource utilization of solid waste.

[0007] To achieve the above objectives, the present invention provides a low-carbon co-processing melting furnace for steel dust and organic solid waste, comprising a feeding unit, an iron bath pyrolysis unit, and a recovery unit connected in sequence; the iron bath pyrolysis unit includes a furnace body containing molten iron and an oxygen delivery assembly communicating with the upper cavity inside the furnace body; the feeding unit includes a steel dust injection assembly and an organic solid waste injection assembly respectively connected to the furnace body, and an organic solid waste feeding port opened at the top of the furnace body; the recovery unit includes a flue gas recovery assembly connected to an exhaust port opened at the shoulder of the furnace body.

[0008] As a further improvement of the present invention, the steel dust blowing assembly includes a steel dust blowing tank and a steel dust spray gun whose input end is connected to the output end of the steel dust blowing tank; the organic solid waste blowing assembly includes an organic solid waste blowing tank and an organic solid waste spray gun whose input end is connected to the output end of the organic solid waste blowing tank; the top of the organic solid waste feeding port is connected to at least two feeding mechanisms to prevent gas leakage during the feeding process.

[0009] As a further improvement of the present invention, the upper surface of the molten iron in the furnace body contains a slag layer; the output ends of the steel dust spray gun and the organic solid waste spray gun are inserted into the slag layer.

[0010] As a further improvement of the present invention, the oxygen delivery assembly includes an oxygen tank and an oxygen lance whose input end is connected to the output end of the oxygen tank, and the output end of the oxygen lance is located above the slag layer.

[0011] As a further improvement of the present invention, the number of oxygen lances is four, and the four oxygen lances are evenly distributed around the furnace body.

[0012] As a further improvement of the present invention, the mass ratio of steel dust and organic solid waste injected into the furnace body is (2-4):(6-8); the organic solid waste includes organic solid waste particles with a particle size ≤6mm injected through the organic solid waste injection component and organic solid waste blocks with a particle size of 10-20mm fed through the organic solid waste feeding port.

[0013] As a further improvement of the present invention, the smelting temperature inside the furnace is 1400-1600℃.

[0014] As a further improvement of the present invention, the low-carbon co-processing melting furnace for steel dust and organic solid waste further includes an organic solid waste pretreatment mechanism; the organic solid waste pretreatment mechanism includes a screening device connected to the organic solid waste injection assembly, a briquetting device connected to the organic solid waste feeding port, a first crushing device and a second crushing device connected to the input ends of the screening device and the briquetting device respectively, and a first drying device and a second drying device connected to the first crushing device and the second crushing device respectively.

[0015] As a further improvement of the present invention, the flue gas recovery assembly includes a vaporization cooling flue, a dust removal device, and a tail gas treatment device that are sequentially connected to the output end of the exhaust port; the dust removal device is connected to a dust collection bin and is used to collect dust rich in volatile metal elements; the tail gas treatment device is connected to a gas storage tank and is used to collect the treated syngas.

[0016] As a further improvement of the present invention, the side wall of the furnace body is provided with a slag outlet and an iron outlet for discharging slag and molten iron respectively.

[0017] The beneficial effects of this invention are:

[0018] (1) The low-carbon co-processing melting furnace for steel dust and organic solid waste provided by the present invention, by setting organic solid waste spray guns and organic solid waste feeding ports respectively, can carry out targeted treatment of different types of organic solid waste, ensuring that all kinds of organic solid waste can effectively enter the melting furnace to participate in the reaction and improve their utilization efficiency. On this basis, the treated organic solid waste and steel dust enter the melting furnace and undergo high-temperature pyrolysis reduction treatment under iron bath conditions. This can not only use the high temperature of the iron bath to separate the volatile metal elements and iron elements in the steel dust, realizing the efficient separation and value-added utilization of multiple metal elements, but also simultaneously co-process organic solid waste, so that the organic solid waste can be quickly converted into small molecule gases such as CO and H2, realizing the efficient resource utilization of organic solid waste and steel dust.

[0019] (2) The smelting furnace provided by this invention can simultaneously treat both organic solid waste and steel dust by co-processing them. Furthermore, it can use the organic solid waste as a heat source for the steel dust treatment process, eliminating the need for additional fuel. The furnace body can also be modified from old converters or blast furnaces phased out by steel enterprises. This effectively reduces treatment costs while improving resource utilization efficiency and realizing asset preservation and appreciation. Based on the smelting furnace provided by this invention, organic solid waste can be effectively used to co-process steel dust, producing molten iron, dust rich in volatile metal elements, and syngas rich in CO and H2. This syngas can be used as an industrial raw material or industrial gas, and its heat can be effectively recovered for boiler power generation and raw material drying, achieving efficient resource utilization.

[0020] (3) The low-carbon co-processing smelting furnace for steel dust and organic solid waste provided by the present invention further inserts the output ends of the organic solid waste spray gun and the steel dust spray gun into the slag layer on the molten iron, so that the secondary combustion can be carried out in the slag layer instead of in the free space above the slag layer. This allows the combustion heat to be directly absorbed by the slag, which not only has higher heat utilization efficiency, but also makes it easier to transfer the combustion heat to the molten iron, effectively maintaining the temperature and heat balance of the molten pool. Furthermore, it further improves the reaction rate of organic solid waste and steel dust, effectively reduces the generation of difficult-to-treat components such as tar, and improves the quality of syngas to meet the needs of practical applications. Attached Figure Description

[0021] Figure 1 A schematic diagram of the structure of the low-carbon co-processing melting furnace for steel dust and organic solid waste provided by the present invention.

[0022] Figure label:

[0023] 100. Low-carbon co-processing melting furnace for steel dust and organic solid waste; 11. First drying device; 12. First crushing device; 13. Screening device; 21. Second drying device; 22. Second crushing device; 23. Agglomeration device; 31. Third drying device; 41. Steel dust; 42. Steel dust injection tank; 43. Steel dust spray gun; 51. Organic solid waste particles; 52. Organic solid waste injection tank; 53. Organic solid waste spray gun; 61. Feeding mechanism; 62. Organic solid waste feeding port; 63. Organic solid waste blocks; 71. Furnace body; 711. Exhaust port; 712. Slag outlet; 713. Iron tapping port; 714. Slag baffle plate; 72. Molten iron; 73. Slag layer; 74. Oxygen tank; 75. Oxygen lance; 81. Vaporization cooling flue; 82. Dust removal device; 83. Exhaust gas treatment device; 84. Dust collection bin; 85. Gas storage tank. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] It should also be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0026] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0027] Example 1

[0028] like Figure 1 As shown, this embodiment provides a low-carbon co-processing melting furnace for steel dust and organic solid waste, including a feeding unit, an iron bath pyrolysis unit, and a recovery unit connected in sequence; the iron bath pyrolysis unit includes a furnace body 71 containing molten iron 72 and an oxygen delivery assembly communicating with the upper cavity inside the furnace body 71; the feeding unit includes a steel dust injection assembly, an organic solid waste injection assembly, and an organic solid waste feeding port 62 opened at the top of the furnace body 71, respectively connected to the furnace body 71; the recovery unit includes a flue gas recovery assembly connected to an exhaust port 711 opened at the shoulder of the furnace body 71.

[0029] The melting furnace also includes an organic solid waste pretreatment mechanism and a steel dust pretreatment mechanism. The organic solid waste pretreatment mechanism includes a screening device 13 connected to the organic solid waste injection assembly, a briquetting device 23 connected to the organic solid waste feeding port 62, a first crushing device 12 and a second crushing device 22 connected to the input ends of the screening device 13 and the briquetting device 23 respectively, and a first drying device 11 and a second drying device 21 connected to the first crushing device 12 and the second crushing device 22 respectively. With this configuration, easily crushable and readily injectable biomass organic solid waste such as sawdust, straw, rice husks, and wood can be dried and crushed sequentially by the first drying device 11 and the first crushing device 12, then screened by the screening device 13 into organic solid waste particles 51 with a particle size ≤ 6mm, and then directly injected into the melting furnace through the organic solid waste injection assembly. For organic solid waste that is difficult to crush or that is too light to be easily blown, such as waste plastics, waste rubber, and foam cotton, it can be dried and initially crushed sequentially by the second drying device 21 and the second crushing device 22, and then agglomerated by the agglomeration device 23 to form organic solid waste blocks 63 with a particle size of 10-20 mm. These blocks are then directly fed into the melting furnace through the organic solid waste feeding port 62 via the feeding mechanism 61. The steel dust pretreatment mechanism includes a third drying device 31 for drying steel dust 41. In this embodiment, all drying devices are fluidized beds; in other embodiments, they can be selected and adjusted according to actual needs.

[0030] In the above manner, the low-carbon co-processing melting furnace for steel dust and organic solid waste provided in this embodiment can be used to treat different types of organic solid waste in a targeted manner, ensuring that all types of organic solid waste can effectively enter the melting furnace to participate in the reaction, thereby improving their utilization efficiency and increasing the calorific value of the final collected syngas.

[0031] More specifically, the steel dust injection assembly in this embodiment includes a steel dust injection tank 42 and a steel dust spray gun 43 whose input end is connected to the output end of the steel dust injection tank 42, for injecting steel dust 41 into the iron bath pyrolysis unit. In different embodiments of the present invention, the steel dust 41 can be one or more of iron-containing dust such as electric furnace dust, refining furnace bag dust, etc. The organic solid waste injection assembly includes an organic solid waste injection tank 52 and an organic solid waste spray gun 53 whose input end is connected to the output end of the organic solid waste injection tank 52, wherein the input end of the organic solid waste injection tank 52 is connected to the output end of the screening device 13, for injecting the dried, crushed, and screened organic solid waste into the iron bath pyrolysis unit. The steel dust injection tank 42 and the organic solid waste injection tank 52 are respectively connected to a nitrogen tank, for using nitrogen as a carrier for steel dust and organic solid waste.

[0032] The top of the organic solid waste feeding port 62 is also connected to a two-stage feeding mechanism 61, which includes a secondary feeding tank and a primary feeding tank connected sequentially to the top of the organic solid waste feeding port 62, to prevent gas leakage during the feeding process. The input end of the feeding mechanism 61 is connected to the output end of the briquetting device 23, and is used to directly feed the briquetting organic solid waste blocks 63 into the melting furnace through the organic solid waste feeding port 62 via the feeding mechanism 61.

[0033] The oxygen delivery assembly includes an oxygen tank 74 and an oxygen lance 75 whose input end is connected to the output end of the oxygen tank 74, for delivering oxygen into the furnace body 71. There are four oxygen lances 75, evenly distributed around the furnace body 71, and they are inserted obliquely into the furnace body 71 through the side wall, effectively avoiding the problem of excessively high spray caused by a single oxygen lance 75.

[0034] In this embodiment, 30 tons of molten iron 72 at a temperature of 1500℃ are pre-loaded into the furnace body 71. The temperature field of the molten iron 72 is very stable, and the molten iron 72 can rapidly decompose organic solid waste. In the decomposition process of organic solid waste, the molten iron 72 plays an important role as a dispersant, catalyst, harmful element absorbent, and rapid reaction carrier. The upper surface of the molten iron 72 also contains a slag layer 73, which can absorb harmful elements such as sulfur brought into the furnace by organic solid waste and steel dust, and also has excellent heat preservation properties.

[0035] The output ends of both the steel dust spray gun 43 and the organic solid waste spray gun 53 are inserted into the slag layer 73 and located at the interface between the slag layer 73 and the molten iron layer 72. This arrangement reduces the scouring and corrosion of the spray guns by the heat flow from the molten iron 72, and allows secondary combustion to occur within the slag layer 73, rather than in the free space above it. This ensures that the combustion heat is directly absorbed by the slag, resulting in higher thermal efficiency and easier heat transfer to the molten iron 72. It effectively maintains the molten pool temperature and heat balance without requiring a complex furnace body 71 structure, further increasing the reaction rate between organic solid waste and steel dust, effectively reducing the generation of difficult-to-treat components such as tar, and improving the quality of syngas to meet practical application requirements. Meanwhile, the output end of the oxygen lance 75 is located above the slag layer 73. On the one hand, it allows the oxygen atoms injected through the oxygen lance 75 to enter the molten iron 72 and generate CO from the dissolved carbon produced by the cracking of organic solid waste. On the other hand, it also allows the oxygen to undergo secondary combustion with some of the generated CO and H2 to release heat to replenish the heat of the entire molten pool environment.

[0036] The flue gas recovery assembly includes a vaporization cooling flue 81, a dust removal device 82, and a tail gas treatment device 83, which are sequentially connected to the output end of the exhaust port 711. There are two exhaust ports 711, positioned opposite each other on the shoulder of the furnace body 71. This arrangement not only facilitates the smooth discharge of flue gas but also allows the high-temperature flue gas discharged from the two exhaust ports 711 to undergo preliminary cooling through the vaporization cooling flue 81 before entering the dust removal device 82 to collect dust rich in volatile metal elements. Figure 1 The diagram shows the connection of the corresponding structure using only one exhaust port 711 as an example. The connection method of the other exhaust port 711 is the same. Figure 1 The contents are not shown in the diagram. In this embodiment, due to the diverse types of organic solid waste used, including organic solid waste containing the harmful element Cl, some of which will enter the flue gas, a wet scrubbing device is used as the dust removal device 82 to wash away the Cl through wet scrubbing. The dust obtained after dust removal, rich in volatile metal elements, will be collected in the dust collection bin 84. At the same time, the exhaust gas after dust removal will undergo desulfurization and denitrification treatment through the exhaust gas treatment device 83. This exhaust gas treatment device 83 can use activated carbon treatment technology to ensure that the exhaust gas meets ultra-low emission standards before being collected in the gas storage tank 85. The syngas collected in the gas storage tank 85 is rich in CO and H2, has a high calorific value, and can be used for heating various equipment inside the steel enterprise, or for power generation.

[0037] In this embodiment, the organic solid waste used includes three materials: biomass, waste plastics, and foam cotton. The biomass, after pretreatment, is injected into the melting furnace through an organic solid waste injection assembly. The waste plastics and foam cotton are fed into the melting furnace through the organic solid waste inlet 62, with the mass ratio of biomass, waste plastics, and foam cotton controlled at 2:1:1. Simultaneously, electric furnace dust is used as steel dust 41, and the mass ratio of steel dust 41 to organic solid waste is controlled at 3:7. The smelting temperature in the melting furnace is 1500℃. Under these conditions, the collected dust, rich in volatile metal elements, has a zinc content of 69.8% and other volatile metal elements (potassium, sodium, lead, etc.) of 5.8%. The total volume percentage of CO and H2 in the syngas is 65.7%, demonstrating high practical application value and achieving efficient resource utilization of organic solid waste and steel dust 41.

[0038] The side wall of the furnace body 71 is provided with a slag outlet 712 and an iron outlet 713 for discharging slag and molten iron 72 respectively. Both the slag outlet 712 and the iron outlet 713 are controlled by a slag-blocking slide plate 714. The position of the slag outlet 712 is higher than the liquid surface of the molten iron 72 so that a part of the slag is left in the furnace for heat preservation each time the slag is discharged, thereby reducing the heat loss of the molten iron 72.

[0039] The specific treatment method of the low-carbon co-processing melting furnace 100 for steel dust and organic solid waste provided in this embodiment is described below:

[0040] First, the organic solid waste to be treated is classified, and then pretreated according to different categories to form corresponding organic solid waste particles 51 and organic solid waste blocks 63. These are then fed into the melting furnace through organic solid waste spray guns 53 and organic solid waste feeding ports 62, respectively, to participate in the reaction. At the same time, steel dust 41 enters the furnace body 71 through steel dust spray guns 43, and oxygen from oxygen tank 74 also enters the furnace body 71 through oxygen lance 75, allowing the steel dust 41 and various organic solid wastes to undergo pyrolysis under iron bath conditions.

[0041] In the above process, the furnace body 71 contains molten iron 72, and the upper surface of the molten iron 72 contains a slag layer 73. The output end of the oxygen lance 75 is located above the slag layer 73, while the output ends of the steel dust spray lance 43 and the organic solid waste spray lance 53 are both inserted into the slag layer 73. This allows secondary combustion to take place in the slag layer 73, and the combustion heat can be directly absorbed by the slag. This not only results in higher thermal utilization efficiency but also makes it easier to transfer combustion heat to the molten iron 72. While effectively maintaining the temperature and heat balance of the molten pool, it also further improves the reaction rate of organic solid waste and steel dust. The dust rich in volatile metal elements and the syngas rich in CO and H2 produced by the pyrolysis reaction are recovered through a flue gas recovery assembly.

[0042] Through the above methods, the low-carbon co-processing melting furnace 100 for steel dust and organic solid waste provided by the present invention can achieve co-processing of organic solid waste and steel dust 41, and effectively collect and reuse the products, thus realizing the efficient resource utilization of various solid wastes.

[0043] Comparative Examples 1-2

[0044] Comparative Examples 1 and 2 each provide a low-carbon co-processing melting furnace for steel dust and organic solid waste. The differences compared to Example 1 are: Comparative Example 1 does not have a separate organic solid waste feeding port 62; all types of organic solid waste are dried, crushed, and screened before being injected into the melting furnace by the organic solid waste injection assembly; Comparative Example 2, based on Comparative Example 1, adjusts the output ends of the steel dust spray gun 43 and the organic solid waste spray gun 53 so that neither is inserted into the melting layer. Other structures and corresponding process parameters of each comparative example are consistent with Example 1 and will not be repeated here.

[0045] The dust and syngas rich in volatile metal elements collected in Comparative Examples 1 and 2 were analyzed to obtain the total content of volatile metal elements in the dust and the total volume ratio of CO and H2 in the syngas. The results are shown in Table 1.

[0046] Table 1. Composition of products collected from Comparative Examples 1-2

[0047]

[0048] Based on actual usage and the product compositions of Examples 1 and Comparative Examples 1-2, it can be concluded that: compared to the method of uniformly spraying organic solid waste in Comparative Example 1, Example 1, by treating different types of organic solid waste separately, can improve its utilization efficiency and promote the recovery of volatile metal elements in steel dust 41, thereby collecting dust with higher metal content and syngas with higher calorific value; furthermore, in practical applications, some organic solid waste in the melting furnace provided in Comparative Example 1 will adhere to the organic solid waste spray gun 53, causing clogging, requiring frequent replacement of the corresponding spray gun, which is inconvenient. In addition, compared to Comparative Example 2, Examples 1 and Comparative Example 1, by inserting the output ends of the organic solid waste spray gun 53 and the steel dust spray gun 43 into the meltblown layer, can further improve the reaction rate of organic solid waste and steel dust while effectively maintaining the temperature and heat balance of the molten pool, and ensure complete pyrolysis of organic solid waste, thereby significantly increasing the volatile metal content in the collected dust and the calorific value of the syngas.

[0049] Examples 2-3 and Comparative Examples 3-4

[0050] Based on the low-carbon co-processing melting furnace 100 for steel dust and organic solid waste provided in Example 1, Examples 2-3 and Comparative Examples 3-4 each provide a processing method. Compared with the processing method used in Example 1, the difference lies in changing the amount of steel dust added, thereby forming different mass ratios between steel dust and organic solid waste. The mass ratios and product compositions corresponding to each example and comparative example are shown in Table 2. The remaining parameters are consistent with those of Example 1 and will not be repeated here.

[0051] Table 2. Mass ratio of steel dust and organic solid waste and their product composition in Examples 2-3 and Comparative Examples 3-4

[0052]

[0053] Based on the practical application of each embodiment and comparative example, and the data in Table 2, it can be seen that when the relative content of steel dust is too low, it is difficult to effectively enrich the volatile metal elements in the steel dust, resulting in a low metal content in the collected dust. However, when the relative content of steel dust is too high, the volume ratio of CO and H2 in the collected syngas decreases, leading to a decrease in the calorific value of the syngas. Therefore, this invention, by further controlling the mass ratio of steel dust to organic solid waste at (2-4):(6-8), can more effectively leverage the synergistic effect between the two types of solid waste and obtain high-quality products to meet the needs of practical applications.

[0054] In summary, a low-carbon co-processing melting furnace for steel dust and organic solid waste is provided, comprising a feeding unit, an iron bath pyrolysis unit, and a recovery unit connected in sequence. The iron bath pyrolysis unit includes a furnace body 71 containing molten iron 72 and an oxygen delivery assembly connected to the upper cavity inside the furnace body 71. The feeding unit includes a steel dust injection assembly and an organic solid waste injection assembly connected to the furnace body 71, and an organic solid waste feeding port 62 located at the top of the furnace body 71. The recovery unit includes a flue gas recovery assembly connected to an exhaust port 711 located at the shoulder of the furnace body 71. Through the above method, the melting furnace provided by this invention can not only process two types of solid waste simultaneously, but also use organic solid waste as a heat source in the steel dust treatment process, effectively utilizing organic solid waste to co-process steel dust, and producing molten iron 72, dust rich in volatile metal elements, and syngas rich in CO and H2. Furthermore, the reaction rate is fast and the product quality is high, achieving efficient resource utilization of organic solid waste and steel dust.

[0055] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A low-carbon co-processing melting furnace for steel dust and organic solid waste, characterized in that: The system includes a feeding unit, an iron bath pyrolysis unit, and a recovery unit connected in sequence. The iron bath pyrolysis unit includes a furnace body (71) containing molten iron (72) and an oxygen delivery assembly connected to the upper cavity inside the furnace body (71). The feeding unit includes a steel dust injection assembly, an organic solid waste injection assembly, and an organic solid waste inlet (62) located at the top of the furnace body (71), all connected to the furnace body (71). The recovery unit includes a flue gas recovery assembly connected to an exhaust port (711) located at the shoulder of the furnace body (71). Organic solid waste particles with a particle size ≤6mm are injected through the organic solid waste injection assembly, and organic solid waste lumps with a particle size of 10~20mm are fed through the organic solid waste inlet (62). The mass ratio of steel dust (41) and organic solid waste injected into the furnace body (71) is (2~4): (6~8); The organic solid waste includes organic solid waste particles (51) with a particle size ≤ 6 mm and organic solid waste blocks (63) with a particle size of 10~20 mm. The steel dust injection assembly includes a steel dust injection tank (42) and a steel dust spray gun (43) whose input end is connected to the output end of the steel dust injection tank (42). The organic solid waste injection assembly includes an organic solid waste injection tank (52) and an organic solid waste spray gun (53) whose input end is connected to the output end of the organic solid waste injection tank (52). The upper surface of the molten iron (72) in the furnace body (71) contains a slag layer (73). The output ends of the steel dust spray gun (43) and the organic solid waste spray gun (53) are inserted into the slag layer (73) and located at the interface between the slag layer (73) and the molten iron (72) layer. The oxygen delivery assembly includes an oxygen tank (74) and an oxygen lance (75) whose input end is connected to the output end of the oxygen tank (74), the output end of the oxygen lance (75) being located above the slag layer (73).

2. The low-carbon co-processing melting furnace for steel dust and organic solid waste according to claim 1, characterized in that: The top of the organic solid waste feeding port (62) is connected to at least two feeding mechanisms (61) to prevent gas leakage during the feeding process.

3. The low-carbon co-processing melting furnace for steel dust and organic solid waste according to claim 1, characterized in that: The number of oxygen lances (75) is four, and the four oxygen lances (75) are evenly distributed around the furnace body (71).

4. The low-carbon co-processing melting furnace for steel dust and organic solid waste according to claim 1, characterized in that: The smelting temperature inside the furnace body (71) is 1400~1600℃.

5. The low-carbon co-processing melting furnace for steel dust and organic solid waste according to claim 1, characterized in that: It also includes an organic solid waste pretreatment mechanism; the organic solid waste pretreatment mechanism includes a screening device (13) connected to the organic solid waste blowing assembly, a briquetting device (23) connected to the organic solid waste feeding port (62), a first crushing device (12) and a second crushing device (22) respectively connected to the input ends of the screening device (13) and the briquetting device (23), and a first drying device (11) and a second drying device (21) respectively connected to the first crushing device (12) and the second crushing device (22).

6. The low-carbon co-processing melting furnace for steel dust and organic solid waste according to claim 1, characterized in that: The flue gas recovery assembly includes a vaporization cooling flue (81), a dust removal device (82), and a tail gas treatment device (83) that are sequentially connected to the output end of the exhaust port (711); the dust removal device (82) is connected to a dust collection bin (84) and is used to collect dust rich in volatile metal elements; the tail gas treatment device (83) is connected to a gas storage tank (85) and is used to collect the treated syngas.

7. The low-carbon co-processing melting furnace for steel dust and organic solid waste according to claim 1, characterized in that: The side wall of the furnace body (71) is provided with a slag outlet (712) and an iron outlet (713) for discharging slag and molten iron (72) respectively.

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