Method for improving reduction performance of biological sludge pyrolytic carbon and application of pyrolytic carbon in reduction of steel dust and sludge

Abstract

The invention provides a method for improving the reduction performance of pyrolytic carbon in biological sludge and application of the pyrolytic carbon in reduction of steel dust and sludge, and aims at solving the problems of high energy consumption and high carbon emission of a traditional reducing agent in the steel industry and promoting efficient utilization of biomass resources in the field of steel and iron metallurgy. The method comprises the following steps: extracting biological sludge carbon through a toluene solvent to remove oil, and deashing through a sulfuric acid solution, so that the adsorption capacity and catalytic performance of the biological sludge carbon are enhanced, and the reduction efficiency of the biological sludge carbon in the ferrous metallurgy process is improved. The biological sludge carbon subjected to dust removal and oil removal treatment has the specific surface area of 159 m < 2 > / g, the pore volume of 0.14 cm < 3 > / g and the average pore size of 3.4 nm, the specific surface area is remarkably increased, the metallization ratio after the reduction reaction is also greatly improved, and the effectiveness of the method in the aspect of improving the reduction performance of the biological sludge carbon is proved. The carbon emission of the iron and steel industry can be reduced, and powerful support is provided for sustainable development of the iron and steel industry.

Description

Technical Field

[0001] The present invention relates to the technical field of reducing carbon emissions, improving energy utilization efficiency and realizing waste resource utilization, and in particular to a method for improving the pyrolytic carbon reduction performance of biological sludge and the use of the pyrolytic carbon in reducing steel dust sludge. Background Art

[0002] The steel industry is a key sector influencing global economic growth, but its energy consumption primarily comes from carbon dioxide emissions. Approximately 80% of these emissions are directly derived from the use of fossil fuels such as coal and coking. According to the International Panel on Climate Change (ICCP)'s "Special Report on Global Warming of 1.5°C," to effectively limit the global average temperature rise to 1.5°C above pre-industrial levels, the international community must complete a deep decarbonization transition by the mid-21st century and establish a carbon-neutral development paradigm. Achieving this strategic goal will help substantially reduce the probability of climate system instability and significantly alleviate the frequency of extreme weather events such as heat waves, heavy rains, and droughts, as well as the secondary disasters they cause. The key path to a low-carbon transition in the steel industry lies in restructuring its energy consumption system. By establishing a renewable energy-dominated energy supply structure and gradually replacing traditional fossil fuels such as coal and coke, these systemic changes require not only cleaner production processes and the development of a comprehensive carbon reduction technology chain covering the entire production cycle, but also strategically promoting the evolution of energy utilization models towards sustainability. The coordinated implementation of the above-mentioned multi-dimensional innovation system is a key breakthrough in driving the steel industry's transformation to an environmentally friendly, resource-saving, and technology-intensive development model. In existing technologies, the use of traditional fossil fuels such as coal and coke as reducing agents not only leads to high energy consumption but also causes serious carbon emissions. Biomass fuels have come into everyone's attention due to their renewable, carbon-neutral, low sulfur content, low ash content, high activity, high specific surface area, and stable pore structure. Using them as reducing agents to replace traditional fossil energy sources such as coal and coke for the reduction of steel dust and sludge has proposed a new approach. However, as a potential alternative reducing agent, the performance of biosludge carbon is not yet sufficient to meet industrial needs. Summary of the Invention

[0003] This invention addresses the high energy consumption and high carbon emission issues of traditional reducing agents in the steel industry and proposes an innovative solution. It aims to significantly improve the performance of biosludge carbon as a steel dust reducing agent by optimizing its physicochemical properties.

[0004] In order to solve the above technical problems, the first aspect of the present invention is to propose a method for improving the carbon reduction performance of biological sludge pyrolysis.

[0005] This method effectively optimizes the specific surface area, pore structure and surface chemical properties of biosludge carbon through a series of pretreatment processes, including degreasing and deashing steps. The steps are as follows:

[0006] (1) Raw material pretreatment and oil removal: Place an appropriate amount of biosludge carbon powder into a Soxhlet extraction apparatus and accurately measure a preset volume of toluene solvent into a round-bottom flask. After extraction at 100°C for approximately 10 hours, the extraction process is considered complete when the toluene solvent in the Soxhlet extraction apparatus becomes completely transparent. The treated deoiled biosludge carbon is transferred to a constant temperature drying oven and fully dried at 80°C.

[0007] (2) Raw material pretreatment and deashing: Weigh a certain amount of deoiled biosludge carbon powder and transfer it to a round-bottom flask. Accurately measure a certain amount of sulfuric acid solution with a concentration of 0.05-0.5 mol / L and add it to the flask. Use a magnetic stirrer to regularly stir the mixed system under the preset temperature conditions. After completing the acid washing process, filter the sample and wash it thoroughly. Then, transfer the washed sample to a vacuum drying oven and continue drying for 12 hours until the sample is neutral.

[0008] The second aspect of the present invention is to provide a biological sludge pyrolysis carbon obtained by the above method of the present invention, the biological sludge pyrolysis carbon has a specific surface area of 159m 2 / g, pore volume 0.14cm 3 / g, average pore size 3.4nm.

[0009] A third aspect of the present invention provides the use of the biomass pyrolytic carbon obtained in the present invention in the reduction of steel dust. In the reduction reaction, the biomass pyrolytic carbon and steel dust raw material C:O ratio is 1:1, the reaction temperature is 1000°C, and the reaction time is 0.5 hours. The reactor is a tubular furnace, and the reaction is carried out under an argon atmosphere.

[0010] Through the above-mentioned technical solution, the present invention successfully solves the problem of insufficient performance of biosludge carbon reducing agents in the prior art, and provides an efficient and environmentally friendly alternative reducing agent for the steel industry. Experimental results show that the specific surface area of biosludge carbon after deashing and degreasing treatment is significantly increased, and the metallization rate after the reduction reaction is also greatly improved, which proves the effectiveness of this method in improving the reduction performance of biosludge carbon. The technical solution of the present invention not only helps to reduce carbon emissions in the steel industry, but also promotes the efficient utilization of biomass resources, providing strong support for the sustainable development of the steel industry.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] (1) Process Optimization and Cost-Effectiveness: This invention significantly optimizes the physical and chemical properties of biosludge carbon through pretreatment steps such as oil removal and deashing, while reducing energy consumption and complexity in the preparation process. This improvement not only enhances the performance of biosludge carbon but also reduces production costs, making it more economical for industrial applications.

[0013] (2) Resource Utilization and Circular Economy: This invention fully utilizes biosludge as a waste resource, converting it into a highly efficient steel dust reducing agent, thus achieving high-value utilization of waste. This technical approach is consistent with the concept of a circular economy and provides new possibilities for the sustainable utilization of biomass resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The BET curve of the biosludge carbon sample was not subjected to oil and ash removal in this method;

[0015] Figure 2 BET curve of deashing biological sludge carbon sample for this method;

[0016] Figure 3 BET curve of biosludge carbon sample for oil and ash removal in this method; DETAILED DESCRIPTION

[0017] The specific embodiments of the present invention are given below. The specific embodiments are only used to further illustrate the present invention and do not limit the scope of protection of the present invention.

[0018] The present invention provides a method for improving the reduction performance of biosludge pyrolysis carbon. Through a series of sophisticated pretreatment steps, including degreasing and deashing, the physicochemical properties of biosludge carbon are significantly optimized. This method not only enhances the adsorption capacity and catalytic performance of biosludge carbon, but also improves its reduction efficiency in steelmaking processes when the resulting biosludge pyrolysis carbon is reduced to steel dust. The method comprises the following steps:

[0019] (1) An appropriate amount of biosludge carbon powder, obtained from Suzhou Yunqing Environmental Energy Technology Co., Ltd., which mainly consists of carbon and a small amount of ash, was placed in a Soxhlet extraction apparatus. A certain amount of toluene solvent was measured and injected into a round-bottom flask. When the toluene solvent in the Soxhlet extraction apparatus became completely transparent, the extraction process was considered complete.

[0020] (2) taking out the extracted sample loaded with pyrolytic carbon black in step (1), transferring it to a constant temperature drying oven, and performing a thorough drying treatment to obtain deoiled biosludge carbon powder;

[0021] (3) Weigh a certain amount of the deoiled biosludge carbon powder obtained in step (2), transfer it to a round-bottom flask, and add a certain amount of sulfuric acid solution to the flask;

[0022] (4) Under preset temperature conditions, the mixed system in step (3) is regularly stirred using a magnetic stirrer. After the pickling process is completed, the sample is filtered and fully washed, and then the washed sample is transferred to a vacuum drying oven for continuous drying.

[0023] Example 1

[0024] Weigh 1.0g of deoiled biosludge carbon powder and transfer it to a 100mL round-bottom flask. Accurately measure 100mL of 0.1mol / L sulfuric acid solution and add it to the flask. Stir the mixture regularly using a magnetic stirrer at a preset temperature. After the acid wash process, filter and thoroughly wash the sample. Then, transfer the cleaned sample to a vacuum drying oven and dry it for 12 hours until the sample is neutral.

[0025] Example 2

[0026] Weigh 0.5g of biosludge carbon powder and place it in a filter paper bag. Then transfer the sample to be treated to the Soxhlet extraction device and accurately measure the preset volume of toluene solvent into the round-bottom flask. After completing the sealed connection between the Soxhlet extractor and the condenser according to the specifications, transfer the entire reaction device to the fume hood. Extraction is carried out on a heating sleeve at 100°C. After about 10 hours of extraction, when the toluene solvent in the Soxhlet extraction device is completely transparent, the extraction process is considered complete. Take out the extracted sample loaded with pyrolytic carbon black, transfer it to a constant temperature drying oven, and fully dry it at 80°C.

[0027] Example 3

[0028] A sample of untreated biomass sludge carbon and steel dust sludge, mixed in a 1:1 carbon-to-carbon ratio, was reduced at 1000°C using a tube furnace to simulate the reducing environment of a rotary hearth furnace. The sample was placed in a corundum container, which was then placed in the tube furnace. Under an inert atmosphere of argon, the temperature was raised to 1000°C and maintained for 0.5 hours. After the reaction, the sample was cooled to room temperature under an argon stream, removed, labeled, and recorded as Sample 1.

[0029] Example 4

[0030] A sample of deashed biomass sludge carbon and steel dust sludge, mixed in a 1:1 carbon-to-carbon ratio, was reduced at 1000°C using a tube furnace to simulate the reduction environment of a rotary hearth furnace. The sample was placed in a corundum container, which was then placed in the tube furnace. Under an inert atmosphere of argon, the temperature was raised to 1000°C and maintained for 0.5 hours. After the reaction, the sample was cooled to room temperature under an argon stream, removed, labeled, and recorded as Sample 2.

[0031] Example 5

[0032] A sample of deashed and degreased biomass sludge carbon and steel dust sludge, mixed in a 1:1 carbon to oxygen ratio, was reduced at 1000°C using a tube furnace to simulate the reducing environment of a rotary hearth furnace. The sample was placed in a corundum container, which was then placed in the tube furnace. Under an inert atmosphere of argon, the temperature was raised to 1000°C and maintained for 0.5 hours. After the reaction, the sample was cooled to room temperature under an argon stream, removed, labeled, and recorded as Sample 3.

[0033] Example 6

[0034] The sample after reduction in Example 3 was subjected to specific surface area and porosity testing. This method uses a physical adsorption instrument to measure the specific surface area and pore size distribution of the sample. The selected instruments are the microporous adsorption instrument ASAP2020 and the mesoporous adsorption instrument Triatar3000 from Micromeritics, USA. Before the experiment, the sample was degassed at 200°C for 12 hours, and the test temperature was set to 77K. Figure 1 shown.

[0035] Example 7

[0036] The sample after reduction in Example 4 was subjected to specific surface area and porosity testing. This method uses a physical adsorption instrument to measure the specific surface area and pore size distribution of the sample. The selected instruments are the microporous adsorption instrument ASAP2020 and the mesoporous adsorption instrument Triatar3000 from Micromeritics, USA. Before the experiment, the sample was degassed at 200°C for 12 hours, and the test temperature was set to 77K. Figure 2 shown.

[0037] Example 8

[0038] The sample after reduction in Example 5 was subjected to specific surface area and porosity testing. This method uses a physical adsorption instrument to measure the specific surface area and pore size distribution of the sample. The selected instruments are the microporous adsorption instrument ASAP2020 and the mesoporous adsorption instrument Triatar3000 from Micromeritics, USA. Before the experiment, the sample was degassed at 200°C for 12 hours, and the test temperature was set to 77K. Figure 3 shown.

[0039] Example 9

[0040] The sample after embodiment 3 reduction is carried out reduction performance test, and full-valent iron inductively coupled plasma (ICP) is recorded;The content of metallic iron, using national standard method " the mensuration of slag metallic iron content ferric chloride - potassium dichromate titration method " (YB / T4725-2018) is recorded, accurately weigh 0.5g granularity and be no more than the sample of 0.080mm, pending sample is transferred in the conical flask of pre-dried process, accurately measure 100mL ferric chloride solution and inject in bottle, complete rapid sealing container after liquid addition, and reaction system is placed in magnetic stirring apparatus and continuously stirred, and the control reaction time is 30 minutes to ensure fully mixing. Subsequently, the mixture after stirring is filtered using double-layer qualitative filter paper, and deionized water is rinsed conical flask 4 to 5 times, filter paper 6 to 8 times, to ensure that the material not participating in the reaction is thoroughly removed. Add 10 mL of sulfuric acid, 5 mL of phosphoric acid, and 4 to 5 drops of sodium diphenylamine sulfonate indicator to the filtrate. Then, titrate with a 0.1 mol / L potassium dichromate standard titrant. Continue titrating until the solution develops a stable color and exhibits a characteristic purple color. Throughout the experiment, the sample must first be sieved through a 0.080 mm sieve, then dried in a 105°C oven for 2 hours, and then cooled to room temperature in a desiccator. To ensure the reliability of the data obtained, each sample should be measured at least twice independently.

[0041] Example 10

[0042] The sample after embodiment 4 reduction is carried out reduction performance test, metallization determination mode is identical with embodiment 9, accurately weigh 0.5g granularity and is no more than the sample of 0.080mm, pending sample is transferred in the conical flask of pre-drying process, accurately measure 100mL ferric chloride solution and inject in bottle, complete rapid sealed container after liquid addition, and reaction system is placed in magnetic stirring apparatus and is continuously stirred, and the control reaction time is 30 minutes to ensure sufficient mixing. Subsequently, double-layer qualitative filter paper is adopted to filter the mixture after stirring, and deionized water is rinsed conical flask 4 to 5 times, filter paper 6 to 8 times, to ensure that the material that does not participate in reaction is thoroughly removed. 10mL sulfuric acid, 5mL phosphoric acid and 4 to 5 diphenylamine sodium sulfonate indicators are added in filtrate, the potassium dichromate standard volumetric solution that concentration is 0.1mol / L is used immediately to carry out titration experiment, and continuously titrating to solution color development is stable and presents characteristic purple as terminal point. During the entire experiment, the sample needs to be screened through a 0.080mm sieve, then dried in an oven at 105°C for 2 hours, and then cooled to room temperature in a desiccator. To ensure the reliability of the obtained data, each sample should be measured at least twice independently.

[0043] Example 11

[0044] The sample after embodiment 5 reduction is carried out reduction performance test, metallization determination mode is identical with embodiment 9, accurately weigh 0.5g granularity and is no more than the sample of 0.080mm, pending sample is transferred in the conical flask of pre-drying process, accurately measure 100mL ferric chloride solution and inject in bottle, complete rapid sealed container after liquid addition, and reaction system is placed in magnetic stirring apparatus and is continuously stirred, and the control reaction time is 30 minutes to ensure sufficient mixing. Subsequently, double-layer qualitative filter paper is adopted to filter the mixture after stirring, and deionized water is rinsed conical flask 4 to 5 times, filter paper 6 to 8 times, to ensure that the material that does not participate in reaction is thoroughly removed. 10mL sulfuric acid, 5mL phosphoric acid and 4 to 5 diphenylamine sodium sulfonate indicators are added in filtrate, the potassium dichromate standard volumetric solution that concentration is 0.1mol / L is used immediately to carry out titration experiment, and continuously titrating to solution color development is stable and presents characteristic purple as terminal point. During the entire experiment, the sample needs to be screened through a 0.080mm sieve, then dried in an oven at 105°C for 2 hours, and then cooled to room temperature in a desiccator. To ensure the reliability of the obtained data, each sample should be measured at least twice independently.

[0045] Performance test results of the application product:

[0046] Table 1 Specific surface area and porosity of samples 1, 2 and 3

[0047] sample <![CDATA[Specific surface area (m 2 / g)]]> <![CDATA[Pore volume (cm 3 / g)]]> Average pore size (nm) 1 53.0 0.003 27.9 2 99.0 0.09 3.7 3 159 0.14 3.4

[0048] Table 2 Reduction of samples 1, 2, and 3

[0049]

[0050] Based on the above experimental results, after improvements such as deashing and oil removal, the steel dust sludge reducing agent replaced by biosludge carbon exhibited a significant increase in specific surface area and a significant improvement in metallization rate after the reduction reaction. This demonstrates that this method can effectively improve the reduction performance of biosludge carbon reducing agents and promote their application in steel metallurgy. Any matters not described in this invention apply to the prior art.

[0051] It should be further explained that the above implementation methods and examples are only used to understand the technical solution of the present invention. Any obvious adjustments and modifications made to the technical solution of the present invention that belong to the technical concept of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A method for improving the carbon reduction performance of biological sludge pyrolysis, characterized in that The following steps are involved: (1) Place an appropriate amount of biosludge carbon powder into a Soxhlet extraction apparatus, measure a certain amount of toluene solvent and inject it into a round-bottom flask. When the toluene solvent in the Soxhlet extraction apparatus becomes completely transparent, the extraction process is considered complete. (2) taking out the extracted sample loaded with pyrolytic carbon black in step (1), transferring it to a constant temperature drying oven, and performing sufficient drying treatment to obtain deoiled biosludge carbon powder; (3) Weigh a certain amount of the deoiled biosludge carbon powder obtained in step (2), transfer it to a round-bottom flask, and add a certain amount of sulfuric acid solution to the flask; (4) Under preset temperature conditions, the mixed system in step (3) is regularly stirred using a magnetic stirrer. After the pickling process is completed, the sample is filtered and fully washed, and then the washed sample is transferred to a vacuum drying oven for continuous drying.

2. The method according to claim 1, characterized in that In step (1), the extraction heating temperature is 100° C., the extraction time is 10 h, and the solvent is distilled and recycled.

3. The method according to claim 1, characterized in that In step (2), the heating temperature of the drying oven is 80°C.

4. The method according to claim 1, wherein In step (3), the concentration of the sulfuric acid solution is 0.05 to 0.5 mol / L.

5. The method according to claim 1, characterized in that In step (4), the drying time is 12 h, until the sample is in a neutral state.

6. A biological sludge pyrolysis carbon obtained by the method according to any one of claims 1 to 5, characterized in that: The specific surface area of the biological sludge pyrolysis carbon is 159m 2 / g, pore volume 0.14cm 3 / g, average pore size 3.4nm.

7. Use of the biological sludge pyrolysis carbon according to claim 6 in reducing steel dust sludge.

8. The use according to claim 7, characterized in that In the reduction reaction, the ratio of biological sludge pyrolysis carbon and steel dust sludge raw material C:O was 1:1, the reaction temperature was 1000℃, and the reaction time was 0.5h.

9. The use according to claim 8, characterized in that The reactor adopts a tubular furnace and the reaction is carried out under an argon atmosphere.

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