A method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestate.

Abstract

This invention relates to the field of energy storage and alkali metal secondary battery anode materials, and discloses a method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestion liquid, comprising the following steps: heating and thoroughly mixing biomass powder with catalytic cracking slurry to obtain a mixed raw material; heating and carbonizing the mixed raw material under a nitrogen atmosphere at normal pressure to obtain a carbonized product; mixing the carbonized product with the digestion liquid, filtering, washing, and drying the filter residue to obtain a multi-level porous soft and hard carbon composite material; collecting the filtrate to recover the FCC catalyst digestion liquid. This method simultaneously prepares soft and hard carbon composite materials and recovers FCC. The biomass surface has abundant oxygen-containing functional groups, which can form a strong adsorption effect on the solid catalyst particles in the FCC slurry. The preparation of soft and hard carbon composite materials using biomass and FCC slurry solves the difficulty of comprehensive utilization of FCC slurry. The solid catalyst particles can act as a "template agent" during the carbonization process of the mixed raw material formed by biomass and FCC slurry.

Description

Technical Field

[0001] This invention relates to the field of energy storage and alkali metal secondary battery anode materials, specifically a method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestion solution. Background Technology

[0002] Carbon materials have advantages such as wide availability and low cost, thus showing broad development prospects in the field of alkali metal secondary battery anode materials. Common carbon materials include graphite (unsuitable for sodium-ion battery anode materials), hard carbon, soft carbon, and various derived carbon materials. Among them, the capacity of soft carbon anode materials is mainly generated above 0.2V, which not only has stable cycle performance but also reduces safety issues caused by battery short circuits. However, the interlayer spacing of soft carbon is relatively narrow compared to hard carbon, which is not conducive to the insertion and extraction of sodium ions, providing fewer active sites for sodium ions, and the sodium storage capacity is generally in the range of 100-250mAh g-1. Hard carbon materials are rich in disordered carbon microcrystals, with larger short-range ordered carbon interlayer spacing, and higher defects and porosity. This structural feature makes hard carbon materials have a rich sodium storage environment, and their sodium storage capacity can reach over 400mAh g-1. However, hard carbon materials generally suffer from low coulombic efficiency and poor cycle stability in the first cycle of the battery.

[0003] Therefore, combining the advantages of soft and hard carbon, and using soft and hard carbon composite materials for sodium-ion battery anode materials, has great commercial application potential. Precursors for hard carbon materials are generally aromatic hydrocarbon resins and biomass. Aromatic hydrocarbon resins cost 10,000-20,000 RMB / t, making the preparation of hard carbon using resin precursors costly; while biomass precursors are widely available in nature and have the advantage of low cost (1,000-5,000 RMB / t). Catalytic cracking (FCC) slurry is a low-value-added petrochemical byproduct rich in polycyclic aromatic hydrocarbons and is a raw material for producing soft carbon materials such as carbon black and needle coke. my country's FCC slurry production alone reaches 10-20 Mt / a, but due to the high content of solid catalyst particles in FCC slurry, its comprehensive utilization is difficult. Therefore, we propose a method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestate. Summary of the Invention

[0004] (a) Technical problems to be solved

[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestion solution, thus solving the aforementioned problems.

[0006] (II) Technical Solution

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: a method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestion solution, comprising the following steps:

[0008] Step 1: Heat and thoroughly mix biomass powder with catalytic cracking slurry to obtain a mixed feedstock;

[0009] Step 2: The mixed raw materials are heated and carbonized under a nitrogen atmosphere at normal pressure to obtain carbonized products;

[0010] Step 3: After mixing the carbonization product with the digestion solution, filter, wash, and dry the filter residue to obtain a multi-level porous soft and hard carbon composite material. The filtrate can be collected to recover the FCC catalyst digestion solution.

[0011] Preferably, the biomass is lignocellulose.

[0012] Preferably, the total content of cellulose and hemicellulose in the lignocellulose is ≥40wt%, and the lignocellulose is one or more of crop straw, sugarcane bagasse, pine powder, and camellia fruit shell powder.

[0013] Preferably, the mass ratio of biomass powder to catalytic cracking slurry is 1:0.5-2, the heating temperature is 50-200℃, and the stirring time is 0.5-10h.

[0014] Preferably, the heating rate in the second step is 0.5℃~10℃, and after heating to 600~1600℃, it is kept at that temperature for 1-6 hours.

[0015] Preferably, the mixing time in the third step is 0.5-10 hours.

[0016] Preferably, the digestion solution in the third step is aqua regia or hydrofluoric acid, the mass ratio of carbonized product to digestion solution is 1:10-50, and the filtration washing solution is a 0.5 mol / L hydrochloric acid solution.

[0017] (III) Beneficial Effects

[0018] Compared with the prior art, the present invention provides a method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestion solution, which has the following beneficial effects:

[0019] 1. This method for simultaneously preparing soft and hard carbon composite materials and recycling FCC utilizes the abundant oxygen-containing functional groups on the surface of biomass, which can form a strong adsorption effect on solid catalyst particles in FCC slurry. The preparation of soft and hard carbon composite materials using biomass and FCC slurry solves the difficulty of comprehensive utilization of FCC slurry. The solid catalyst particles can act as a "template agent" in the carbonization process of the mixed raw materials formed by biomass and FCC slurry.

[0020] 2. The method for simultaneously preparing soft and hard carbon composite materials and recovering FCC uses solvents to remove carbonization products, resulting in multi-level porous soft and hard carbon composite materials and FCC catalyst digestion solution. The FCC catalyst digestion solution can be used for subsequent recovery of high-value-added catalytically active components in the FCC catalyst. Attached Figure Description

[0021] Figure 1 This is a data diagram of Embodiment 1 of the present invention;

[0022] Figure 2 This is a rate performance diagram of the soft and hard carbon composite nanomaterials obtained in Example 1. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] A method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestate includes the following steps:

[0025] Raw material preparation

[0026] Biomass powder and catalytic cracking (FCC) slurry are heated and thoroughly mixed to obtain a mixed feedstock.

[0027] The biomass is lignocellulose;

[0028] The total content of cellulose and hemicellulose is ≥40wt%, and the lignocellulose is one or more of the following: crop straw, sugarcane bagasse, pine powder, and camellia fruit shell powder;

[0029] The mass ratio of biomass powder to catalytic cracking (FCC) slurry is 1:0.5-2; the heating temperature is 50-200℃; and the stirring time is 0.5-10h.

[0030] carbonization

[0031] The mixed raw materials from step 1 are heated to 600–1600°C under a nitrogen atmosphere at atmospheric pressure at a heating rate of 0.5°C–10°C, and then held at that temperature for 1–6 hours to obtain the carbonized product.

[0032] Cleaning

[0033] After stirring and mixing the carbonized product obtained in step 2 with the digestion solution for 0.5-10 hours, filter, wash, and dry the filter residue to obtain a multi-level porous soft and hard carbon composite material. The filtrate can be collected to recover the FCC catalyst digestion solution.

[0034] The digestion solution is aqua regia or hydrofluoric acid, and the mass ratio of carbonization product to digestion solution is 1:10-50.

[0035] The filtration washing solution was a 0.5 mol / L hydrochloric acid solution.

[0036] Example 1, please refer to Figure 1-2

[0037] 10g of straw powder and 5g of catalytic cracking (FCC) slurry were heated to 50℃ and stirred for 0.5h. Then, under a nitrogen atmosphere at atmospheric pressure, the mixture was heated to 600℃ at a heating rate of 0.5℃ and held for 1h to obtain approximately 4.8g of carbonized product. 48g of aqua regia was mixed with the obtained carbonized product for 0.5h, then filtered, washed, and dried to obtain approximately 2.8g of a hierarchical porous soft-hard carbon composite material. The filtrate was collected for the recovery of the FCC catalyst digestion solution. The obtained hierarchical porous soft-hard carbon composite material has a BET specific surface area of ​​262.83m². 2 / g, the reversible sodium storage capacity at a charge / discharge current density of 0.1A / g is 385mAh g. -1 .

[0038] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestion solution, characterized in that, Includes the following steps: Step 1: Heat and thoroughly mix biomass powder with catalytic cracking slurry to obtain a mixed feedstock; Step 2: The mixed raw materials are heated and carbonized under a nitrogen atmosphere at normal pressure to obtain carbonized products; Step 3: After stirring and mixing the carbonization product with the digestion solution, filter, wash and dry the filter residue to obtain a multi-level porous soft and hard carbon composite material. The filtrate can be collected to recover the FCC catalyst digestion solution. The biomass is lignocellulose; The total cellulose and hemicellulose content of the lignocellulose is ≥40 wt%, and the lignocellulose is one or more of crop straw, sugarcane bagasse, pine powder, and camellia fruit shell powder; The mass ratio of biomass powder to catalytic cracking slurry is 1:0.5-2, the heating temperature is 50-200℃, and the stirring time is 0.5-10h; The heating rate in the second step is 0.5℃~10℃, and after heating to 600~1600℃, it is held for 1-6 hours; The mixing time in the third step is 0.5-10 hours.

2. The method for preparing soft and hard carbon composite materials and recovering FCC catalyst digestate according to claim 1, characterized in that: The digestion solution in the third step is aqua regia or hydrofluoric acid, the mass ratio of carbonization product to digestion solution is 1:10~50, and the filtration washing solution is 0.5mol / L hydrochloric acid solution.

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