High-calorific-value low-slagging-rate biomass fuel

Abstract

The application discloses an environment-friendly energy-saving high-calorific-value biomass fuel, which is prepared by adding guaiacol polyether potassium phosphate and polydiallyldimethylammonium chloride to improve the performance of a biomass hydrothermal carbonization catalyst, and further improve the calorific value of the biomass fuel; the urea-formaldehyde resin binder is modified to enhance the bonding performance of the urea-formaldehyde resin and the water resistance of the biomass fuel, and meanwhile, the shrinkage rate of the urea-formaldehyde resin is reduced; and finally, the active white clay is modified and coated with peroxycalcium carbonate to further reduce the slagging rate of the biomass fuel.

Description

Technical Field

[0001] This invention belongs to the field of biomass fuel technology, specifically relating to a high-calorific-value, low-slagging-rate biomass fuel. Background Technology

[0002] Biomass fuel refers to fuel made by burning biomass materials, which are generally agricultural and forestry wastes such as straw, sawdust, bagasse, and rice husks. The application of biomass fuel is mainly biomass briquettes, which are a new type of clean fuel made by crushing, mixing, extruding, drying, and other processes to produce briquettes or pellets that can be burned directly.

[0003] Biomass fuel molding processes include hot pressing, cold pressing, and carbonization. Among them, carbonization produces biomass fuel with the highest calorific value. Carbonization generally uses catalysts to catalyze the reaction, but as the reaction proceeds, impurities generated can affect the effectiveness of the catalyst, thereby affecting the carbonization process of biomass and the calorific value of the fuel.

[0004] After carbonization, the lignin content of biomass fuel is greatly reduced. Therefore, the bonding strength generated by its own bonding force alone is insufficient during molding. It is necessary to add a binder to enhance its molding strength. However, the added binder, such as urea-formaldehyde resin, has problems with poor water resistance and large shrinkage rate after biomass fuel molding due to its own properties, which in turn affects the mechanical strength of biomass fuel. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing high-calorific-value, low-slagging-rate biomass fuel.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention includes the following steps:

[0007] A high-calorific-value, low-slagging-rate biomass fuel, the specific preparation steps are as follows:

[0008] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1~2 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0009] (2) Add reactant a into a sealed reactor, then add 1.3-1.5% of lauryl polyether potassium phosphate and 0.8-1.0% of polydiallyl dimethyl ammonium chloride by mass of particles a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 160-170°C at a rate of 10°C / min, and keep the temperature at 200-300 r / min for 60-70 min. Then continue to raise the temperature to 210-220°C and react for 90-100 min. After the reaction is completed, cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0010] (3) First, mix 1.4 to 1.6 parts of urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1 to 1.2 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 48 to 52°C and 15 to 17 MPa to obtain biomass briquette fuel.

[0011] Furthermore, the urea-formaldehyde resin described in step (4) also includes the following treatment method:

[0012] (1) Add 0.25~0.45% of its mass of perfluoropolyether-based surfactant to KH-560, and then add water to make a dilute solution with a concentration of 1~1.2% to obtain the modified solution;

[0013] (2) Mix polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:2~3 to obtain a coating solution. Then immerse 6~10μm wollastonite in the coating solution for 3~5 minutes, and then dry to remove the anhydrous ethanol. Repeat this process 3 times to obtain the modifier.

[0014] (3) The modified urea-formaldehyde resin is obtained by uniformly mixing the urea-formaldehyde resin, the modified liquid and the modifier at a mass ratio of 1:0.25~0.35:0.15~0.25.

[0015] Further, the method for preparing the anti-slagging agent in step (4) is as follows: the activated clay and calcium percarbonate are mixed in a mass ratio of 5:3 to obtain the agent.

[0016] Furthermore, the activated clay also includes the following treatment method:

[0017] Activated clay and deionized water were mixed at a mass ratio of 1:8 and stirred until homogeneous to obtain a suspension. Then, 0.8-0.9% of tetrabutylammonium hexafluorophosphate (TCA) by mass of activated clay was added and stirred until homogeneous. The pH was then adjusted to 10.6-11.0, and the mixture was heated to 80-90℃ and reacted for 2.5-3.5 hours. After the reaction was completed, the mixture was filtered, and the filter cake was washed three times with anhydrous ethanol. The cake was then dried and pulverized to obtain the modified activated clay.

[0018] Furthermore, the calcium percarbonate also includes the following treatment method:

[0019] Hydrogenated rosin glycerol ester and acetone are mixed evenly at a mass ratio of 1:1.2~1.8 to obtain coating solution a. Then, calcium percarbonate is immersed in coating solution a for 3~4 minutes and then dried at 24~26℃. This cycle is repeated 3 times to obtain coated calcium percarbonate.

[0020] The beneficial effects of this invention are as follows:

[0021] (1) Due to the high temperature and pressure of the hydrothermal reaction and the impurities generated as the hydrothermal reaction proceeds, the catalytic performance of acetic acid and lithium chloride will be affected, which in turn affects the hydrothermal carbonization. Potassium lauryl ether phosphate can enhance the permeability of acetic acid and lithium chloride, making it easier for them to enter the biomass for reaction. On the other hand, it can also accelerate the separation of lignin and hemicellulose in biomass. At the same time, potassium lauryl ether phosphate can also enhance the thermal stability of acetic acid.

[0022] (2) Adding polydiallyldimethylammonium chloride to the reaction system can provide additional chloride ions to play a catalytic role. At the same time, after adding polydiallyldimethylammonium chloride to the reaction system, it can flocculate the organic and material impurities generated in the reaction, reduce the amount of impurities attached to the surface of biomass, and thus improve the effect of biomass carbonization. Polydiallyldimethylammonium chloride also has chlorine resistance, which can reduce the corrosive effect of chloride ions on the reaction equipment. In addition, polydiallyldimethylammonium chloride is safe, non-toxic, and has good stability, so it can be used with confidence.

[0023] (3) Adding KH-560 and wollastonite directly to urea-formaldehyde resin has no obvious effect. The water resistance and shrinkage rate of urea-formaldehyde resin have not been significantly improved. Mixing perfluoropolyether surfactant and KH-560 can enhance the dispersibility of KH-560 in urea-formaldehyde resin, so that KH-560 can fully react with urea-formaldehyde resin to enhance the water resistance of urea-formaldehyde resin. On the other hand, it can also adjust the viscosity of urea-formaldehyde resin so that it can better bond with biomass fuel. At the same time, the perfluoropolyether surfactant can form a dense fluorinated surface layer on the surface of biomass fuel after it is formed, further enhancing the water resistance of biomass fuel.

[0024] (4) Coating wollastonite with polyoxyethylene hydrogenated castor oil can enhance the compatibility of wollastonite in urea-formaldehyde resin. During the stirring process, wollastonite can be evenly dispersed in urea-formaldehyde resin. On the other hand, the coating also has a slow-release effect. After wollastonite is evenly dispersed in urea-formaldehyde resin, polyoxyethylene hydrogenated castor oil will slowly dissolve in the water contained in urea-formaldehyde resin during the stirring process. After the polyoxyethylene hydrogenated castor oil is completely dissolved, wollastonite can continue to undergo cross-linking reaction with KH-560, further enhancing the bonding strength and other properties of urea-formaldehyde resin. At the same time, the polyoxyethylene hydrogenated castor oil dissolved in water can also play a role in stabilizing the resin before the urea-formaldehyde resin is cured.

[0025] (5) Tetrabutylammonium hexafluorophosphate can stabilize the sandwich structure through intercalation reaction to improve its adsorption performance. At the same time, tetrabutylammonium hexafluorophosphate can also be applied to the surface of activated clay through physical adsorption. Tetrabutylammonium hexafluorophosphate has the effect of ion-pair reagent and can also bind some alkali metals. At the same time, because hexafluorophosphate has a strong electronegativity, it can also enhance the adsorption performance of activated clay.

[0026] (6) Calcium percarbonate is easily decomposed when it contains water and is at a high temperature. Coating it with hydrogenated rosin glycerol can isolate moisture and also has a heat insulation effect. Even if calcium percarbonate decomposes partially due to high temperature during biomass molding, the oxygen produced by decomposition can be retained inside. At the same time, hydrogenated rosin glycerol will slightly soften due to high temperature during molding, which also enhances the bonding strength of biomass molten fuel. During biomass combustion, hydrogenated rosin glycerol can also act as a combustible to promote combustion. Implementation

[0027] The present invention will be further described in detail below with reference to the embodiments. Example 1

[0028] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0029] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0030] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of potassium lauryl ether phosphate and 0.9% by weight of polydiallyl dimethyl ammonium chloride of particle a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, and then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0031] (3) First, mix 1.5 parts of urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 2

[0032] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0033] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0034] (2) Add reactant a into a sealed reactor, then add 1.3% by weight of potassium lauryl ether phosphate and 1.0% by weight of polydiallyl dimethyl ammonium chloride of particle a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 160°C at a rate of 10°C / min, keep the temperature at 200 r / min for 70 min, and then continue to raise the temperature to 220°C for 90 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0035] (3) First, mix 1.4 parts of urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.2 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 48°C and 17MPa pressure to obtain biomass briquettes. Example 3

[0036] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0037] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:2 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0038] (2) Add reactant a into a sealed reactor, then add 1.5% by weight of lauryl polyether potassium phosphate and 0.8% by weight of granules a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 170°C at a rate of 10°C / min, keep the temperature at 300 r / min for 60 min, then continue to raise the temperature to 210°C for 100 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0039] (3) First, mix 1.6 parts of urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1 part of anti-slagging agent and mix evenly. Then, extrude the mixture at 52°C and 17MPa pressure to obtain biomass briquettes. Example 4

[0040] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0041] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0042] (2) Add reactant a into a sealed reactor, then add potassium stearate at 1.4% of the mass of particle a and polydiallyl dimethyl ammonium chloride at 0.9% of the mass of particle a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, and then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0043] (3) First, mix 1.5 parts of urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 5

[0044] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0045] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0046] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of potassium lauryl ether phosphate and 0.9% by weight of aluminum sulfate respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0047] (3) First, mix 1.5 parts of urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 6

[0048] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0049] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100℃ oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a ratio of 1:1.5 (g / mL) and stirred evenly to obtain reactant a.

[0050] (2) Add reactant a into a sealed reactor, introduce nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, then continue to raise the temperature to 215°C for 95 min, and after the reaction is completed, cool naturally to room temperature, centrifuge and filter to obtain biochar, and dry the biochar to remove moisture.

[0051] (3) First, mix 1.5 parts of urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 7

[0052] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0053] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0054] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of lauryl polyether potassium phosphate and 0.9% by weight of granules a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 215°C at a rate of 10°C / min, and keep the reaction at 250 r / min for 160 min. After the reaction is completed, cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0055] (3) First, mix 1.5 parts of urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 8

[0056] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0057] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0058] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of lauryl polyether potassium phosphate and 0.9% by weight of granules a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to obtain biochar.

[0059] (3) First, mix 1.5 parts of urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes.

[0060] The biomass fuels prepared in Examples 1-8 were tested for calorific value according to GB / T 30727-2014 "Method for Determination of Calorific Value of Solid Biomass Fuels". The specific data are shown in Table 1.

[0061] Table 1. Calorific value of biomass fuel in each embodiment.

[0062] Implementation Items Calorific value (MJ / kg) Example 1 28.44 Example 2 28.32 Example 3 28.29 Example 4 24.84 Example 5 24.51 Example 6 20.69 Example 7 26.65 Example 8 25.78

[0063] As shown in Table 1, Examples 1 to 3 have the highest calorific value. Examples 4 and 5, which replaced potassium lauryl ether phosphate and polydiallyl dimethyl ammonium chloride respectively, have significantly lower calorific values ​​compared to Example 1. Example 6 has the lowest calorific value because no catalyst was added to catalyze the hydrothermal reaction, resulting in low biomass carbonization efficiency and ultimately a low calorific value. The low calorific value of Example 7 may be due to the lack of a stepwise heating reaction, which prevented the complete separation of lignin and hemicellulose in the biomass, affecting subsequent carbonization. The calorific value of Example 8 is also lower than that of Example 1, possibly because the moisture in the biochar after centrifugation was not removed, affecting subsequent combustion and consequently the calorific value of the biomass fuel. Example 9

[0064] Add 0.35% by mass of a perfluoropolyether-based surfactant to KH-560, and then add water to prepare a 1.1% dilute solution to obtain the modified solution.

[0065] A coating solution was prepared by mixing polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:2.5. Then, 8μm wollastonite was immersed in the coating solution for 4 minutes, followed by drying to remove the anhydrous ethanol. This process was repeated 3 times to obtain the modifier.

[0066] Modified urea-formaldehyde resin is obtained by uniformly mixing urea-formaldehyde resin, modifying liquid and modifier at a mass ratio of 1:0.3:0.2.

[0067] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0068] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0069] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of potassium lauryl ether phosphate and 0.9% by weight of polydiallyl dimethyl ammonium chloride of particle a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, and then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0070] (3) First, mix 1.5 parts of modified urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 10

[0071] Add 0.25% by mass of a perfluoropolyether-based surfactant to KH-560, and then add water to prepare a 1.2% concentration dilute solution to obtain the modified solution.

[0072] A coating solution was prepared by mixing polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:2. Then, 10μm wollastonite was immersed in the coating solution for 3 minutes. After drying, the anhydrous ethanol was removed. This process was repeated 3 times to obtain the modifier.

[0073] Modified urea-formaldehyde resin is obtained by uniformly mixing urea-formaldehyde resin, modifying liquid and modifier at a mass ratio of 1:0.35:0.15.

[0074] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0075] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0076] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of potassium lauryl ether phosphate and 0.9% by weight of polydiallyl dimethyl ammonium chloride of particle a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, and then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0077] (3) First, mix 1.5 parts of modified urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 11

[0078] Add 0.45% by mass of a perfluoropolyether-based surfactant to KH-560, and then add water to prepare a 1% concentration dilute solution to obtain the modified solution.

[0079] A coating solution was prepared by mixing polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:3. Then, 6μm wollastonite was immersed in the coating solution for 5 minutes. After drying, the anhydrous ethanol was removed. This process was repeated 3 times to obtain the modifier.

[0080] Modified urea-formaldehyde resin is obtained by uniformly mixing urea-formaldehyde resin, modifying liquid and modifier at a mass ratio of 1:0.25:0.25.

[0081] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0082] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0083] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of potassium lauryl ether phosphate and 0.9% by weight of polydiallyl dimethyl ammonium chloride of particle a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, and then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0084] (3) First, mix 1.5 parts of modified urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 12

[0085] Add 0.35% sodium dodecyl sulfate by mass to KH-560, and then add water to make a 1.1% dilute solution to obtain the modified solution.

[0086] The rest is the same as in Example 9. Example 13

[0087] Sodium carboxymethyl cellulose and deionized water were mixed at a volume ratio of 1:2.5 to obtain a coating solution. Then, 8 μm wollastonite was immersed in the coating solution for 4 min. After drying, the deionized water was removed. This process was repeated 3 times to obtain the modifier.

[0088] The rest is the same as in Example 9. Example 14

[0089] Add 1% by mass of a perfluoropolyether-based surfactant to KH-560, and then add water to prepare a 1.1% concentration dilute solution to obtain the modified solution.

[0090] The rest is the same as in Example 9. Example 15

[0091] Add 0.35% by mass of a perfluoropolyether-based surfactant to KH-560, and then add water to prepare a 4% concentration dilute solution to obtain the modified solution.

[0092] The rest is the same as in Example 9. Example 16

[0093] A coating solution was prepared by mixing polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:6. Then, 8μm wollastonite was immersed in the coating solution for 4 minutes, followed by drying to remove the anhydrous ethanol. This process was repeated 3 times to obtain the modifier.

[0094] The rest is the same as in Example 9. Example 17

[0095] A coating solution was prepared by mixing polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:2.5. Then, 15μm wollastonite was immersed in the coating solution for 4 minutes, followed by drying to remove the anhydrous ethanol. This process was repeated 3 times to obtain the modifier.

[0096] The rest is the same as in Example 9. Example 18

[0097] A coating solution was prepared by mixing polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:2.5. Then, 8μm wollastonite was immersed in the coating solution for 8 minutes, followed by drying to remove the anhydrous ethanol. This process was repeated 3 times to obtain the modifier.

[0098] The rest is the same as in Example 9.

[0099] Part of the biomass fuel prepared in Examples 9-18 was placed in an environment with a temperature of 25°C and a humidity of 75% for 10 days. Then, the mass m1 before placement and the mass m2 after placement were measured. The mass change rate was calculated by the formula a = (m2-m1) / m1. The water resistance of the biomass fuel was evaluated by the mass change rate. The shrinkage rate was calculated by the formula b = (V1-V2) / V1, where V1 represents the volume before curing and V2 represents the volume after curing. At the same time, part of the biomass fuel prepared in Examples 10-19 was placed in a soft packaging bag and dropped freely from a height of 2m onto a steel plate of a specified thickness or a hardened ground. The drops were repeated 5 times. The proportion of biomass fuel with a mass change of less than 5% before and after the drops was measured and recorded as the shatter resistance c. The specific data are shown in Table 2.

[0100] Table 2. Mechanical performance data of biomass fuels in Examples 9-18

[0101] Implementation Items Mass change rate a (%) Shrinkage rate b (%) Friction resistance c (%) Example 1 8.52 0.98 78.0 Example 9 0.24 0.12 98.7 Example 10 0.31 0.16 96.7 Example 11 0.35 0.15 97.3 Example 12 5.23 0.15 92.7 Example 13 0.48 0.81 84.7 Example 14 0.41 0.18 92.0 Example 15 1.55 0.34 92.7 Example 16 0.36 0.60 90.0 Example 17 0.47 0.69 90.7 Example 18 0.33 0.14 96.0

[0102] Table 2 shows that the biomass fuels prepared in Examples 9-11 exhibited the best performance in terms of mass change rate, shrinkage rate, and compressive strength. In Example 1, the urea-formaldehyde resin was not modified, resulting in poor performance in all three parameters. Example 12 showed poor water resistance, possibly due to the replacement surfactant failing to enhance water resistance and exhibiting weaker dispersibility, which in turn affected the biomass fuel's shatter resistance. Example 13, which replaced the coating material, showed a significant decrease in shatter resistance compared to Example 9. The biomass fuel prepared in Example 14 showed slightly reduced shatter resistance compared to Example 9, possibly due to excessive addition of the perfluoropolyether-based surfactant, which affected the curing of the urea-formaldehyde resin and consequently the shatter resistance. Example 15's shatter resistance was due to the silane coupling agent. Excessive concentration affected the water resistance and shatter resistance of biomass fuel, possibly because the high concentration of silane coupling agent led to its self-polymerization reaction, thus affecting the dispersibility and stability of urea-formaldehyde resin. The high shrinkage rate and poor shatter resistance in Example 16 were likely due to the low concentration of the coating solution, resulting in incomplete coating of wollastonite, which in turn affected the dispersibility of wollastonite in urea-formaldehyde resin and caused premature reaction between wollastonite and the silane coupling agent. The high shrinkage rate and poor shatter resistance in Example 17 were likely due to the excessively large particle size of wollastonite, which affected its dispersibility in urea-formaldehyde resin and reduced its specific surface area, ultimately affecting the strength and shrinkage rate of the resin after curing. The performance data of Example 18 and Example 9 were not significantly different, indicating that the coating immersion time in Example 9 was the optimal time. Example 19

[0103] Activated clay and deionized water were mixed at a mass ratio of 1:8 and stirred until homogeneous to obtain a suspension. Then, 0.85% of tetrabutylammonium hexafluorophosphate by mass of activated clay was added, stirred until homogeneous, and the pH was adjusted to 10.8. The mixture was then heated to 85°C and reacted for 3 hours. After the reaction was completed, the mixture was filtered, and the filter cake was washed three times with anhydrous ethanol. The cake was then dried and pulverized to obtain modified activated clay.

[0104] Hydrogenated rosin glycerol ester and acetone were mixed evenly at a mass ratio of 1:1.5 to obtain coating solution a. Then, calcium percarbonate was immersed in coating solution a for 3.5 minutes and then dried at 25°C. This process was repeated 3 times to obtain coated calcium percarbonate.

[0105] Add 0.35% by mass of a perfluoropolyether-based surfactant to KH-560, and then add water to prepare a 1.1% dilute solution to obtain the modified solution.

[0106] A coating solution was prepared by mixing polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:2.5. Then, 8μm wollastonite was immersed in the coating solution for 4 minutes, followed by drying to remove the anhydrous ethanol. This process was repeated 3 times to obtain the modifier.

[0107] Modified urea-formaldehyde resin is obtained by uniformly mixing urea-formaldehyde resin, modifying liquid and modifier at a mass ratio of 1:0.3:0.2.

[0108] The anti-slagging agent is obtained by mixing modified activated clay and coated calcium percarbonate at a mass ratio of 5:3.

[0109] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0110] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of potassium lauryl ether phosphate and 0.9% by weight of polydiallyl dimethyl ammonium chloride of particle a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, and then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0111] (3) First, mix 1.5 parts of modified urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 20

[0112] Activated clay and deionized water were mixed at a mass ratio of 1:8 and stirred until homogeneous to obtain a suspension. Then, 0.8% of tetrabutylammonium hexafluorophosphate by mass of activated clay was added, stirred until homogeneous, and the pH was adjusted to 11.0. The mixture was then heated to 80℃ and reacted for 3.5 hours. After the reaction was completed, the mixture was filtered, and the filter cake was washed three times with anhydrous ethanol. The cake was then dried and pulverized to obtain modified activated clay.

[0113] Hydrogenated rosin glycerol ester and acetone were mixed evenly at a mass ratio of 1:1.2 to obtain coating solution a. Then, calcium percarbonate was immersed in coating solution a for 4 minutes and then dried at 24°C. This process was repeated 3 times to obtain coated calcium percarbonate.

[0114] Add 0.35% by mass of a perfluoropolyether-based surfactant to KH-560, and then add water to prepare a 1.1% dilute solution to obtain the modified solution.

[0115] A coating solution was prepared by mixing polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:2.5. Then, 8μm wollastonite was immersed in the coating solution for 4 minutes, followed by drying to remove the anhydrous ethanol. This process was repeated 3 times to obtain the modifier.

[0116] Modified urea-formaldehyde resin is obtained by uniformly mixing urea-formaldehyde resin, modifying liquid and modifier at a mass ratio of 1:0.3:0.2.

[0117] The anti-slagging agent is obtained by mixing modified activated clay and coated calcium percarbonate at a mass ratio of 5:3.

[0118] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0119] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of potassium lauryl ether phosphate and 0.9% by weight of polydiallyl dimethyl ammonium chloride of particle a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, and then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0120] (3) First, mix 1.5 parts of modified urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 21

[0121] Activated clay and deionized water were mixed at a mass ratio of 1:8 and stirred until a suspension was obtained. Then, 0.9% of tetrabutylammonium hexafluorophosphate (TCA) by mass of activated clay was added and stirred until a uniform pH was obtained. The pH was then adjusted to 10.6 and the mixture was heated to 90°C for 2.5 hours. After the reaction was completed, the mixture was filtered and the filter cake was washed three times with anhydrous ethanol. The cake was then dried and pulverized to obtain modified activated clay.

[0122] Hydrogenated rosin glycerol ester and acetone were mixed evenly at a mass ratio of 1:1.8 to obtain coating solution a. Then, calcium percarbonate was immersed in coating solution a for 3 minutes and then dried at 26°C. This process was repeated 3 times to obtain coated calcium percarbonate.

[0123] Add 0.35% by mass of a perfluoropolyether-based surfactant to KH-560, and then add water to prepare a 1.1% dilute solution to obtain the modified solution.

[0124] A coating solution was prepared by mixing polyoxyethylene hydrogenated castor oil and anhydrous ethanol at a volume ratio of 1:2.5. Then, 8μm wollastonite was immersed in the coating solution for 4 minutes, followed by drying to remove the anhydrous ethanol. This process was repeated 3 times to obtain the modifier.

[0125] Modified urea-formaldehyde resin is obtained by uniformly mixing urea-formaldehyde resin, modifying liquid and modifier at a mass ratio of 1:0.3:0.2.

[0126] An anti-slagging agent is obtained by mixing activated clay and calcium percarbonate in a mass ratio of 5:3.

[0127] (1) The wood chips are crushed using a pulverizer, and after sieving, particles with a diameter of less than 3 mm are retained. The particles are placed in a purification device to remove impurities, and then dried in a 100°C oven to obtain particle a. Then, 20 parts of particle a and deionized water are mixed at a material-liquid ratio of 1:1.5 (g / mL). Then, 1% of the mass of particle a, lithium chloride and glacial acetic acid are added respectively, and the mixture is stirred evenly to obtain reactant a.

[0128] (2) Add reactant a into a sealed reactor, then add 1.4% by weight of potassium lauryl ether phosphate and 0.9% by weight of polydiallyl dimethyl ammonium chloride of particle a respectively. Purge nitrogen into the reactor to replace the air in the reactor, then raise the temperature to 165°C at a rate of 10°C / min, keep the temperature at 250 r / min for 65 min, and then continue to raise the temperature to 215°C for 95 min. After the reaction is completed, let it cool naturally to room temperature, centrifuge and filter to separate the biochar, and dry the biochar to remove moisture.

[0129] (3) First, mix 1.5 parts of modified urea-formaldehyde resin and 0.6% of its mass of ammonium chloride evenly, then add 15 parts of dried biochar and 1.1 parts of anti-slagging agent and mix evenly. Then, extrude the mixture at 50°C and 16MPa pressure to obtain biomass briquettes. Example 22

[0130] Activated clay and deionized water were mixed at a mass ratio of 1:8 and stirred until a suspension was obtained. Then, 0.85% of the activated clay mass of dodecyltrimethylammonium bromide was added, stirred until a uniform solution was obtained, and the pH was adjusted to 10.8. The mixture was then heated to 85°C and reacted for 3 hours. After the reaction was completed, the mixture was filtered, and the filter cake was washed three times with anhydrous ethanol. The cake was then dried and pulverized to obtain the modified activated clay.

[0131] The rest is the same as in Example 19. Example 23

[0132] Paraffin and acetone were mixed evenly at a mass ratio of 1:1.5 to obtain coating solution a. Then, calcium percarbonate was immersed in coating solution a for 3.5 minutes and then dried at 25°C. This process was repeated 3 times to obtain coated calcium percarbonate.

[0133] The rest is the same as in Example 19. Example 24

[0134] Activated clay and deionized water were mixed at a mass ratio of 1:8 and stirred until a suspension was obtained. Then, 0.85% of tetrabutylammonium hexafluorophosphate (TCA) by mass of activated clay was added and stirred until a uniform pH was obtained. The pH was then adjusted to 12.0 and the mixture was heated to 85°C and reacted for 3 hours. After the reaction was completed, the mixture was filtered and the filter cake was washed three times with anhydrous ethanol. The cake was then dried and pulverized to obtain modified activated clay.

[0135] The rest is the same as in Example 19. Example 25

[0136] Activated clay and deionized water were mixed at a mass ratio of 1:8 and stirred until homogeneous to obtain a suspension. Then, 0.85% of tetrabutylammonium hexafluorophosphate by mass of activated clay was added, stirred until homogeneous, and the pH was adjusted to 10.8. The mixture was then heated to 100℃ and reacted for 3 hours. After the reaction was completed, the mixture was filtered, and the filter cake was washed three times with anhydrous ethanol. The cake was then dried and pulverized to obtain modified activated clay.

[0137] The rest is the same as in Example 19. Example 26

[0138] Activated clay and deionized water were mixed at a mass ratio of 1:8 and stirred until homogeneous to obtain a suspension. Then, 0.85% of tetrabutylammonium hexafluorophosphate by mass of activated clay was added, stirred until homogeneous, and the pH was adjusted to 10.8. The mixture was then heated to 85°C and reacted for 5 hours. After the reaction was completed, the mixture was filtered, and the filter cake was washed three times with anhydrous ethanol. The cake was then dried and pulverized to obtain modified activated clay.

[0139] The rest is the same as in Example 19. Example 27

[0140] Hydrogenated rosin glycerol ester and acetone were mixed evenly at a mass ratio of 1:3 to obtain coating solution a. Then, calcium percarbonate was immersed in coating solution a for 3.5 minutes and then dried at 25°C. This process was repeated 3 times to obtain coated calcium percarbonate.

[0141] The rest is the same as in Example 19. Example 28

[0142] Hydrogenated rosin glycerol ester and acetone were mixed evenly at a mass ratio of 1:1.5 to obtain coating solution a. Then, calcium percarbonate was immersed in coating solution a for 6 minutes and then dried at 25°C. This process was repeated 3 times to obtain coated calcium percarbonate.

[0143] The rest is the same as in Example 19.

[0144] The slagging rate of the biomass fuels prepared in Examples 1 and 19-28 was determined according to NB / T 34025-2015 "Test Method for Slagging Properties of Biomass Solid Fuels". The specific data are shown in Table 3.

[0145] Table 3. Slagging rate of biomass fuel in each embodiment

[0146] Implementation Items Slagging rate (%) Example 19 1.24 Example 20 1.27 Example 21 1.28 Example 22 6.16 Example 23 5.77 Example 24 2.47 Example 25 3.43 Example 26 3.11 Example 27 2.02 Example 28 1.30 Example 1 7.81

[0147] Table 3 shows that Examples 19-21 had the lowest slagging rates, indicating that their anti-slagging agents were most effective. Example 1, lacking modification of the activated clay and coating with calcium percarbonate, had the highest slagging rate. Example 22, by replacing tetrabutylammonium hexafluorophosphate with dodecyltrimethylammonium bromide, showed a significantly increased slagging rate compared to Example 19. Example 23, by replacing the coating material hydrogenated rosin glycerol ester with paraffin wax, had a slagging rate similar to Example 22. The increased slagging rate in Example 24 may be due to an increased pH value during activated clay modification; excessively high pH values ​​inhibited the modification reaction, thus affecting the modification effect. Example 25, on the other hand, involved increasing the activated clay... The reaction temperature was too high, which may have inhibited the modification reaction and caused side reactions, thus increasing the slagging rate. Example 26 extended the reaction time of the activated clay. An excessively long reaction time may have caused the chemical bonds formed in the reaction to break, thereby affecting the modification effect of the activated clay. Example 27 increased the amount of solvent acetone. The reason for the increased slagging rate may be that the low concentration of the coating solution caused some of the peroxycalcium carbonate to be incompletely coated, and some of it had decomposed before combustion, thus affecting the slagging rate. Example 28 extended the coating time, but the slagging rate was similar to that of Example 19, indicating that the coating time of Example 19 was the optimal time.

Claims

1. A high-calorific-value, low-slagging-rate biomass fuel, characterized by: The specific preparation method is: (1) Wood chips are crushed by a crusher, and the particles with a particle size of less than 3 mm are retained after sieving. The particles are placed into a impurity removal device to remove impurities, and then placed into a 100℃ oven to dry to obtain particles a. Then 20 parts of particles a and deionized water are mixed according to a solid-liquid ratio of 1:1~2 (g / mL), and then 1% lithium chloride and glacial acetic acid of the mass of particles a are added respectively. After stirring uniformly, reaction a is obtained; (2) Reaction a is added to a sealed reaction kettle, and then 1.3~1.5% potassium lauryl polyether phosphate and 0.8~1.0% polydiallyldimethylammonium chloride of the mass of particles a are added respectively. Nitrogen is introduced into the reaction kettle to replace the air in the kettle. Then, the temperature is raised to 160~170℃ at a speed of 10℃ / min, and the reaction is carried out at a rotation speed of 200~300r / min for 60~70min. Then, the temperature is continuously raised to 210~220℃ for 90~100min. After the reaction is completed, it is naturally cooled to room temperature. Centrifugal filtration separation is carried out to obtain biochar. The biochar is dried to remove water; (3) First, 1.4~1.6 parts of urea-formaldehyde resin and 0.6% ammonium chloride of the mass of urea-formaldehyde resin are uniformly mixed. Then, 15 parts of dried biochar and 1~1.2 parts of anti-slagging agent are uniformly mixed. The mixture is extruded into a briquette at a temperature of 48~52℃ and a pressure of 15~17MPa to obtain a biomass briquette.

2. The high-calorific-value and low-cinder-rate biomass fuel according to claim 1, characterized in that: The urea-formaldehyde resin also includes the following treatment method: (1) Add 0.25~0.45% perfluoropolyether surfactant to KH-560, then add water to prepare a dilute solution with a concentration of 1~1.2%, and the modified liquid is obtained; (2) Mix polyoxyethylene hydrogenated castor oil and anhydrous ethanol according to a volume ratio of 1:2~3 to obtain a coating liquid. Then, immerse the 6~10μm wollastonite in the coating liquid for 3~5min, and then dry to remove the anhydrous ethanol. Repeat the cycle for 3 times to obtain the modifier; (3) Mix the urea-formaldehyde resin, the modified liquid and the modifier according to a mass ratio of 1:0.25~0.35:0.15~0.25 to obtain the modified urea-formaldehyde resin.

3. The high calorific value and low slagging rate biomass fuel as claimed in claim 1, wherein: The preparation method of the anti-slagging agent is: mix active clay and calcium peroxycarbonate according to a mass ratio of 5:3 to obtain the anti-slagging agent.

4. The high-heating-value, low-clinkering-bio mass fuel of claim 3, wherein: The active clay also includes the following treatment method: Mix the active clay and deionized water according to a mass ratio of 1:8, and stir uniformly to obtain a suspension. Then, add 0.8~0.9% tetrabutylammonium hexafluorophosphate of the mass of active clay, stir uniformly, adjust the pH value to 10.6~11.0, and then heat to 80~90℃ for 2.5~3.5h. After the reaction is completed, perform suction filtration, wash the filter cake with anhydrous ethanol for 3 times, and then dry and crush to obtain the modified active clay.

5. A high calorific value and low slagging rate biomass fuel as claimed in claim 3, wherein the biomass fuel is prepared by mixing the biomass with the binder in the ratio of 1 : 0.1 to 1 : 0.

5. The calcium peroxycarbonate also includes the following treatment method: Mix hydrogenated rosin glyceride and acetone according to a mass ratio of 1:1.2~1.8 to obtain a coating liquid a. Then, immerse the calcium peroxycarbonate in the coating liquid a for 3~4min, and then dry at 24~26℃. Repeat the cycle for 3 times to obtain the coated calcium peroxycarbonate.