Biomass pellet fuel and method for preparing the same

Abstract

The application discloses a kind of biomass pellet fuel and its preparation method, belong to biomass pellet fuel technical field, the biomass pellet fuel includes following raw materials, according to weight percentage: biomass raw material 68~77%, tea seed cake 15~22%, moisture-proof agent 2~4.5%, combustion-supporting agent 1.5~2.5% and adhesive 3~4%.The structure of the biomass pellet fuel of the application is optimized, has higher calorific value and more excellent moisture-proof effect, and quality is promoted.

Description

Technical Field

[0001] The invention relates to a biomass pellet fuel and a preparation method thereof, belonging to the technical field of biomass pellet fuel. Background Art

[0002] With the environmental pressure and carbon emissions issues brought about by coal resource depletion, biomass fuels have gradually entered the public eye. Biomass fuels are made from agricultural and forestry waste, such as straw, rice husks, corn cobs, nut shells, flowers, and tea leaves, as well as domestic waste. Through crushing, extrusion, and drying, they are made into strips or pellets. They are new clean fuels that can be burned directly, alleviating pollution. Their efficient combustion characteristics can reduce dependence on traditional energy sources such as coal. However, the calorific value of existing biomass pellet fuels remains unsatisfactory. In addition, some biomass pellet fuels deliquesce due to long-term storage, resulting in reduced combustion quality and affecting their calorific value. This has limited the potential for widespread application of biomass pellet fuels. Summary of the Invention

[0003] In order to address at least one problem existing in the above-mentioned prior art, the present invention provides a biomass pellet fuel and a preparation method thereof. The structure of the biomass pellet fuel is optimized, and the fuel has a higher calorific value and a better moisture-proof effect, thereby improving the quality.

[0004] In order to achieve the above-mentioned purpose, the present invention adopts the following technical solution: a biomass pellet fuel, comprising the following raw materials, calculated by weight percentage: 68-77% biomass raw material, 15-22% tea seed cake, 2-4.5% moisture-proof agent, 1.5-2.5% combustion aid and 3-4% adhesive.

[0005] Preferably, the biomass raw materials include the following raw materials, calculated by weight: 30-50 parts of corn cobs, 15-25 parts of corn stalks, and 35-45 parts of cotton stalks.

[0006] Preferably, the sum of the weight parts of the corn cob, corn stalks and cotton stalks is 100 parts.

[0007] Preferably, the combustion improver consists of potassium permanganate, magnesium oxide and aluminum oxide.

[0008] Preferably, the combustion aid is composed of potassium permanganate, magnesium oxide and aluminum oxide in a mass ratio of 1-2:1:2-3.

[0009] Preferably, the moisture-proofing agent consists of montmorillonite and ethyl cellulose.

[0010] Preferably, the moisture-proof agent is composed of montmorillonite and ethyl cellulose in a mass ratio of 1:1.5 to 2.5.

[0011] Preferably, the adhesive consists of rosin and tower bottom heavy oil.

[0012] Preferably, the adhesive is composed of rosin and heavy oil at a mass ratio of 3-4:1.

[0013] The heavy oil at the bottom of the tower in the present application is a heavy component obtained by vacuum distillation in the biodiesel production process.

[0014] The present application also provides a preparation method of biomass pellet fuel, comprising the following steps:

[0015] (1) crushing corn cob, corn straw, cotton stalk and tea seed cake to pass through a 200-mesh screen to obtain crushed solid powder;

[0016] (2) calcining montmorillonite at high temperature and high-speed airflow, then mixing with deionized water and performing high-pressure homogenization treatment to form a montmorillonite dispersion liquid, then adding ethyl cellulose for ultrasonic dispersion treatment, and then stirring and mixing for 20-30 min to obtain a moisture-proof agent dispersion liquid;

[0017] (3) spraying the moisture-proof agent dispersion liquid to the crushed solid powder during stirring, stirring uniformly, drying, then adding a combustion improver and mixing uniformly, and then performing steam explosion treatment to obtain steam explosion solid powder;

[0018] (4) stirring and mixing the steam explosion solid powder with the adhesive uniformly, then vacuum heating and stirring, and then pressing and forming by a forming machine to obtain biomass pellet fuel.

[0019] Preferably, in step (2), the calcination treatment is performed at a temperature of 1100-1150℃, an airflow speed of 5-10 m / s, and for a time of 15-25 min.

[0020] Preferably, in step (2), the high-pressure homogenization treatment is performed at a pressure of 150-200 Mpa and for 10-15 cycles.

[0021] Preferably, in step (2), the amount of deionized water is 20-30% of the weight of the crushed solid powder.

[0022] Preferably, in step (2), the ultrasonic treatment is performed at an ultrasonic power of 400-500 W for a time of 20-30 min.

[0023] Preferably, in step (3), the steam explosion treatment is performed at a temperature of 135-145℃ and a pressure of 1.8-2.2 Mpa for 8-10 min, and then unloaded to normal temperature and pressure within 25-30 s.

[0024] Preferably, in step (4), the vacuum heating is performed at a vacuum degree of 0.02-0.03 MPa, a temperature of 120-130℃, and for a time of 1-2 h.

[0025] Preferably, step (4) is compression molding: extruding into a cylindrical shape of 5 to 6 cm at a temperature of 125 to 135° C. and a pressure of 65 to 70 MPa.

[0026] The beneficial effects of the present invention are as follows: 1. The present invention uses corn cobs, corn stalks and cotton stalks as biomass raw materials, mixes the biomass raw materials, moisture-proof agents, combustion aids, adhesives and rapeseed cakes, optimizes the composition system of biomass pellet fuel, and effectively solves the problem of low combustion calorific value of biomass pellet fuel; 2. At the same time, the present invention adopts steam explosion treatment on the mixed system of biomass raw materials, rapeseed cakes, moisture-proof agents and combustion aids, and then heats them with adhesives in vacuum, and then presses them into shape, so that the structure of biomass pellet fuel is optimized and has higher calorific value; 3. The present invention adopts a moisture-proof agent composed of montmorillonite and ethyl cellulose, and the montmorillonite is calcined with high-temperature and high-speed airflow, homogenized under high pressure, and then mixed with ethyl cellulose for ultrasonic treatment, and then the moisture-proof agent is mixed with the biomass raw materials and rapeseed cakes, which has better barrier properties, so that the biomass pellet fuel has better Good moisture-proof effect, fuel quality is improved, and montmorillonite is mixed in the biomass raw material, which can promote the expansion of the particles and improve the combustion efficiency. At the same time, ethyl cellulose and adhesives work together to promote the raw materials to be more compact during combustion, the raw materials are not easy to disperse, and the combustion is more complete, thereby improving the fuel stability and calorific value; 4. The present invention adopts a combustion-supporting agent composed of potassium permanganate, magnesium oxide and aluminum oxide, so that the biomass pellet fuel has higher combustion efficiency and stability, and its overall calorific value is also improved; the present invention adopts an adhesive composed of rosin and tower bottom heavy oil, so that the biomass particles can be closely combined together during the molding process to form a molded pellet fuel with stable structure, which also promotes the improvement of the moisture resistance of the biomass pellet fuel, and the rosin and tower bottom heavy oil work together to improve the calorific value and combustion performance of the biomass pellet fuel. DETAILED DESCRIPTION

[0027] The following is a clear and complete description of the technical solutions in the implementation of the present invention. The embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the examples, they are carried out according to conventional conditions or the conditions recommended by the manufacturer.

[0028] Example 1

[0029] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are as follows:

[0030] (1) Crush 40 parts of corn cobs, 20 parts of corn stalks, 40 parts of cotton stalks, and 32.3 parts of tea seed cakes until they pass through a 200-mesh sieve to obtain crushed solid powder;

[0031] (2) 1.96 parts of montmorillonite were calcined at a temperature of 1120° C. and a high-speed airflow of 8 m / s for 20 min, then mixed with 33 parts of deionized water and subjected to high-pressure homogenization at a pressure of 180 MPa, and the process was circulated 13 times to form a montmorillonite dispersion, 3.92 parts of ethyl cellulose were added, and ultrasonic dispersion was performed at an ultrasonic power of 450 W for 25 min, followed by stirring and mixing for another 25 min to obtain a moisture-proof agent dispersion;

[0032] (3) During the stirring process, spray a moisture-proof agent dispersion onto the crushed solid powder, stir evenly and dry, then add 2.94 parts of a combustion aid composed of potassium permanganate, magnesium oxide and aluminum oxide in a mass ratio of 1.5:1:2.5, mix evenly, and then steam explode. Heat and pressure are maintained at a temperature of 140°C and a pressure of 2 MPa for 9 minutes, and then discharged to room temperature and pressure within 25 to 30 seconds to obtain steam-exploded solid powder;

[0033] (4) The steam explosion solid powder was mixed with 5.88 parts of an adhesive composed of rosin and tower bottom heavy oil in a mass ratio of 3.5:1, and then stirred for 1.5 hours at a vacuum degree of 0.025 MPa and a temperature of 125°C. The mixture was then pressed into a cylindrical structure of 5 to 6 cm by a molding machine at a temperature of 130°C and a pressure of 67.5 MPa to obtain a biomass pellet fuel;

[0034] The heavy oil at the bottom of the tower in this embodiment is a heavy component obtained by vacuum distillation during the biodiesel production process.

[0035] Example 2

[0036] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are as follows:

[0037] (1) Crush 40 parts of corn cobs, 20 parts of corn straw, 40 parts of cotton straw, and 26.4 parts of tea seed cake until they pass through a 200-mesh sieve to obtain crushed solid powder;

[0038] (2) 2.08 parts of montmorillonite were calcined at a temperature of 1100° C. and a high-speed airflow of 10 m / s for 25 min, then mixed with 37.9 parts of deionized water and subjected to high-pressure homogenization at a pressure of 150 MPa, and the mixture was circulated 15 times to form a montmorillonite dispersion. 4.16 parts of ethyl cellulose were then added, and ultrasonic dispersion was performed at an ultrasonic power of 400 W for 30 min, followed by stirring and mixing for 20 min to obtain a moisture-proof agent dispersion.

[0039] (3) During the stirring process, spray a moisture-proof agent dispersion onto the crushed solid powder, stir evenly and dry, then add 2.1 parts of a combustion aid composed of potassium permanganate, magnesium oxide and aluminum oxide in a mass ratio of 1.5:1:2.5, mix evenly, and then steam explode. Keep the temperature and pressure at 135°C and 1.8 MPa for 10 minutes, and then discharge to room temperature and pressure within 25 to 30 seconds to obtain steam-exploded solid powder;

[0040] (4) The steam explosion solid powder was mixed with 4.2 parts of an adhesive composed of rosin and tower bottom heavy oil in a mass ratio of 3.5:1, and then stirred for 1 hour at a vacuum degree of 0.03 MPa and a temperature of 130°C. The mixture was then pressed into a cylindrical structure of 5 to 6 cm by a molding machine at a temperature of 135°C and a pressure of 65 MPa to obtain biomass pellet fuel;

[0041] The heavy oil at the bottom of the tower in this embodiment is a heavy component obtained by vacuum distillation during the biodiesel production process.

[0042] Example 3

[0043] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are as follows:

[0044] (1) Crush 40 parts of corn cobs, 20 parts of corn stalks, 40 parts of cotton stalks, and 19.5 parts of tea seed cakes until they pass through a 200-mesh sieve to obtain crushed solid powder;

[0045] (2) 0.87 parts of montmorillonite were calcined at a temperature of 1500°C and a high-speed airflow of 5 m / s for 15 minutes, then mixed with 23.9 parts of deionized water and subjected to high-pressure homogenization at a pressure of 200 MPa, and the mixture was circulated 10 times to form a montmorillonite dispersion. 1.73 parts of ethyl cellulose were then added, and ultrasonic dispersion was performed at an ultrasonic power of 500 W for 20 minutes, followed by stirring and mixing for 30 minutes to obtain a moisture-proof agent dispersion.

[0046] (3) During the stirring process, spray a moisture-proof agent dispersion onto the crushed solid powder, stir evenly and dry, then add 3.24 parts of a combustion aid composed of potassium permanganate, magnesium oxide and aluminum oxide in a mass ratio of 1.5:1:2.5, mix evenly, and then steam explode. Keep the temperature and pressure at 145°C and 2.2 MPa for 8 minutes, and then discharge to room temperature and pressure within 25 to 30 seconds to obtain steam-exploded solid powder;

[0047] (4) The steam explosion solid powder was mixed with 4.54 parts of an adhesive composed of rosin and tower bottom heavy oil in a mass ratio of 3.5:1, and then stirred for 1 hour at a vacuum degree of 0.03 MPa and a temperature of 130°C. The mixture was then pressed into a cylindrical structure of 5 to 6 cm by a molding machine at a temperature of 135°C and a pressure of 70 MPa to obtain biomass pellet fuel;

[0048] The heavy oil at the bottom of the tower in this embodiment is a heavy component obtained by vacuum distillation during the biodiesel production process.

[0049] Example 4

[0050] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are as follows:

[0051] (1) Crush 30 parts of corn cobs, 25 parts of corn straw, 45 parts of cotton straw, and 22.9 parts of tea seed cake until they pass through a 200-mesh sieve to obtain crushed solid powder;

[0052] (2) 1.9 parts of montmorillonite were calcined at a temperature of 1130° C. and a high-speed airflow velocity of 7 m / s for 20 min, then mixed with 27 parts of deionized water and subjected to high-pressure homogenization at a pressure of 180 MPa, and the process was circulated 12 times to form a montmorillonite dispersion, 2.8 parts of ethyl cellulose were added, and ultrasonic dispersion was performed at an ultrasonic power of 450 W for 25 min, followed by stirring and mixing for another 25 min to obtain a moisture-proof agent dispersion;

[0053] (3) During the stirring process, spray a moisture-proof agent dispersion onto the crushed solid powder, stir evenly and dry, then add 2.7 parts of a combustion aid composed of potassium permanganate, magnesium oxide and aluminum oxide in a mass ratio of 1:1:2, mix evenly, and then steam explode. Heat and pressure are maintained at a temperature of 140°C and a pressure of 2 MPa for 9 minutes, and then discharged to room temperature and pressure within 25 to 30 seconds to obtain steam-exploded solid powder;

[0054] (4) The steam explosion solid powder was mixed with 4.7 parts of an adhesive composed of rosin and tower bottom heavy oil in a mass ratio of 3:1, and then stirred for 1.5 hours at a vacuum degree of 0.025 MPa and a temperature of 125°C. The mixture was then pressed into a cylindrical structure of 5 to 6 cm by a molding machine at a temperature of 130°C and a pressure of 67.5 MPa to obtain a biomass pellet fuel;

[0055] The heavy oil at the bottom of the tower in this embodiment is a heavy component obtained by vacuum distillation during the biodiesel production process.

[0056] Example 5

[0057] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are as follows:

[0058] (1) corn cob 50 parts, corn straw 15 parts, cotton stalk 35 parts, tea seed cake 29.5 parts are crushed to pass through a 200 mesh screen to obtain crushed solid powder;

[0059] (2) 1.25 parts of montmorillonite is calcined at a temperature of 1120°C and a gas flow rate of 8 m / s for 20 min, then mixed with 32 parts of deionized water and subjected to high pressure homogenization at a pressure of 170 MPa, with 12 cycles of treatment, to form a montmorillonite dispersion liquid, then 3.05 parts of ethyl cellulose is added and subjected to ultrasonic dispersion at an ultrasonic power of 450 W for 25 min, then mixed for another 25 min to obtain a moisture-proof agent dispersion liquid;

[0060] (3) during the stirring process, the moisture-proof agent dispersion liquid is sprayed into the crushed solid powder, which is then dried and mixed with 2.15 parts of combustion aid composed of potassium permanganate, magnesium oxide and aluminum oxide in a mass ratio of 2:1:3, and then subjected to steam explosion treatment at a temperature of 140°C and a pressure of 2 MPa for 10 min, and then discharged to normal temperature and pressure within 25-30 s to obtain steam-exploded solid powder;

[0061] (4) the steam-exploded solid powder is mixed with 4.9 parts of adhesive composed of rosin and bottom heavy oil in a mass ratio of 4:1, and then stirred at a vacuum degree of 0.025 MPa and a temperature of 125°C for 1.5 h, and then pressed into a pellet by a pelletizing machine at a temperature of 130°C and a pressure of 67.5 MPa to form a cylindrical structure with a diameter of 5-6 cm to obtain a biomass pellet fuel;

[0062] The bottom heavy oil in this embodiment is a heavy component obtained by vacuum distillation during the production of biodiesel.

[0063] Example 6

[0064] A biomass pellet fuel and a preparation method thereof, the preparation process comprising the following specific steps:

[0065] (1) corn cob 35 parts, corn straw 20 parts, cotton stalk 35 parts, tea seed cake 22.2 parts are crushed to pass through a 200 mesh screen to obtain crushed solid powder;

[0066] (2) 1.9 parts of montmorillonite is calcined at a temperature of 1120°C and a gas flow rate of 8 m / s for 20 min, then mixed with 28 parts of deionized water and subjected to high pressure homogenization at a pressure of 190 MPa, with 15 cycles of treatment, to form a montmorillonite dispersion liquid, then 3 parts of ethyl cellulose is added and subjected to ultrasonic dispersion at an ultrasonic power of 450 W for 25 min, then mixed for another 25 min to obtain a moisture-proof agent dispersion liquid;

[0067] (3) During the stirring process, spray a moisture-proof agent dispersion onto the crushed solid powder, stir evenly and dry, then add 2.5 parts of a combustion aid composed of potassium permanganate, magnesium oxide and aluminum oxide in a mass ratio of 2:1:2, mix evenly, and then steam explode. Keep the temperature and pressure at 140°C and 2.1 MPa for 10 minutes, and then discharge to room temperature and pressure within 25 to 30 seconds to obtain steam-exploded solid powder;

[0068] (4) The steam explosion solid powder was mixed with 3.7 parts of an adhesive composed of rosin and tower bottom heavy oil in a mass ratio of 3.5:1, and then stirred for 1.5 hours at a vacuum degree of 0.028 MPa and a temperature of 130°C. The mixture was then pressed into a cylindrical structure of 5 to 6 cm by a molding machine at a temperature of 130°C and a pressure of 68 MPa to obtain biomass pellet fuel;

[0069] The heavy oil at the bottom of the tower in this embodiment is a heavy component obtained by vacuum distillation during the biodiesel production process.

[0070] Comparative Example 1

[0071] A biomass pellet fuel and a preparation method thereof, the specific steps of the preparation process are different from those of Example 2 in that: no rapeseed cake is added, wherein: 40 parts of corn cobs, 20 parts of corn stalks, 40 parts of cotton stalks, 1.65 parts of a combustion aid, 3.3 parts of an adhesive, and a moisture-proof agent: 1.65 parts of montmorillonite and 3.29 parts of ethyl cellulose; the rest are exactly the same.

[0072] Comparative Example 2

[0073] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are different from those of Example 2 in that: a moisture-proof agent comprises montmorillonite, ethyl cellulose and lignin, wherein, in step (2), the moisture-proof agent dispersion is prepared by calcining 1.57 parts of montmorillonite under a high-temperature, high-speed airflow at a temperature of 1100° C. and an airflow velocity of 10 m / s for 25 min, then stirring and mixing with 37.9 parts of deionized water and subjecting the mixture to a high-pressure homogenization treatment at a pressure of 150 MPa, and circulating the treatment for 15 times to form a montmorillonite dispersion, then adding 3.12 parts of ethyl cellulose, subjecting the mixture to ultrasonic dispersion at an ultrasonic power of 400 W for 30 min, then stirring and mixing for 20 min, then adding 1.56 parts of lignin, and stirring and mixing for 20 min to obtain a moisture-proof agent dispersion; and the rest of the steps are identical.

[0074] Comparative Example 3

[0075] A biomass pellet fuel and a preparation method thereof. The specific steps of the preparation process are different from those of Example 2 in that methyl cellulose is used instead of ethyl cellulose; the rest are exactly the same.

[0076] Comparative Example 4

[0077] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are different from those of Example 2 in that: the moisture-proof agent is only ethyl cellulose, wherein the moisture-proof agent dispersion in step (2) is: 3.12 parts of ethyl cellulose and 37.9 parts of deionized water are stirred and mixed for 20 minutes, ultrasonically dispersed at an ultrasonic power of 400 W for 30 minutes, and then stirred and mixed for another 20 minutes to obtain the moisture-proof agent dispersion; the rest are exactly the same.

[0078] Comparative Example 5

[0079] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are different from those of Example 2 in that: the moisture-proof agent only contains montmorillonite, wherein, in the moisture-proof agent dispersion of step (2), 1.57 parts of montmorillonite are calcined for 25 minutes under a high-temperature, high-speed airflow at a temperature of 1100° C. and an airflow velocity of 10 m / s, then stirred and mixed with 37.9 parts of deionized water and subjected to high-pressure homogenization treatment at a pressure of 150 MPa, and the treatment is circulated 15 times to form a montmorillonite dispersion, which is then ultrasonically dispersed at an ultrasonic power of 400 W for 30 minutes, and then stirred and mixed for 20 minutes to obtain a moisture-proof agent dispersion; the rest of the steps are identical.

[0080] Comparative Example 6

[0081] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are different from those of Example 2 in that: no adhesive is added, wherein the rapeseed cake is 30.6 parts, and the steam explosion solid powder of step (4) is pressed and formed by a molding machine at a temperature of 135° C. and a pressure of 65 MPa, and extruded into a cylindrical structure of 5 to 6 cm to obtain a biomass pellet fuel; the rest of the steps are exactly the same.

[0082] Comparative Example 7

[0083] A biomass pellet fuel and a preparation method thereof. The specific steps of the preparation process are different from those of Example 2 in that only rosin is contained in the adhesive; the rest are exactly the same.

[0084] Comparative Example 8

[0085] A biomass pellet fuel and a preparation method thereof, the specific steps of the preparation process are different from those of Example 2 in that: only the bottom heavy oil is contained in the adhesive; the rest are exactly the same.

[0086] Comparative Example 9

[0087] A biomass pellet fuel and a preparation method thereof. The specific steps of the preparation process are different from those of Example 2 in that the combustion aid is composed of magnesium oxide and aluminum oxide; the rest are exactly the same.

[0088] Comparative Example 10

[0089] A biomass pellet fuel and a preparation method thereof. The specific steps of the preparation process are different from those of Example 2 in that the combustion aid is composed of potassium permanganate and aluminum oxide; the rest are exactly the same.

[0090] Comparative Example 11

[0091] A biomass pellet fuel and a preparation method thereof. The specific steps of the preparation process are different from those of Example 2 in that the combustion aid is composed of magnesium oxide and potassium permanganate; the rest are exactly the same.

[0092] Comparative Example 12

[0093] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are different from those of Example 2 in that: (3) crushed solid powder is mixed evenly with 2.1 parts of a combustion aid composed of potassium permanganate, magnesium oxide, and aluminum oxide in a mass ratio of 1.5:1:2.5, and then subjected to steam explosion treatment, heat-maintained and pressure-maintained treatment at a temperature of 135° C. and a pressure of 1.8 MPa for 10 minutes, and then discharged to room temperature and pressure within 25 to 30 seconds to obtain steam-exploded solid powder;

[0094] (4) The steam explosion solid powder was mixed with 4.2 parts of an adhesive composed of rosin and tower bottom heavy oil in a mass ratio of 3.5:1, and then stirred for 1 hour at a vacuum degree of 0.03 MPa and a temperature of 130°C. The mixture was then pressed into a cylindrical structure of 5 to 6 cm at a temperature of 135°C and a pressure of 65 MPa. The moisture-proof agent dispersion was then sprayed on the cylindrical structure through a spraying process. After the spraying was completed, the mixture was dried to obtain biomass pellet fuel. The rest was exactly the same.

[0095] Comparative Example 13

[0096] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are different from those of Example 2 in that: (3) during the stirring process, spraying a moisture-proof agent dispersion onto the crushed solid powder, stirring evenly and then drying, then adding 2.1 parts of a combustion aid composed of potassium permanganate, magnesium oxide and aluminum oxide in a mass ratio of 1.5:1:2.5, and mixing evenly to obtain a mixed solid powder;

[0097] (4) The mixed solid powder was mixed with 4.2 parts of an adhesive composed of rosin and tower bottom heavy oil in a mass ratio of 3.5:1, and then stirred for 1 hour at a vacuum degree of 0.03 MPa and a temperature of 130°C. The mixture was then pressed into a cylindrical structure of 5 to 6 cm by a molding machine at a temperature of 135°C and a pressure of 65 MPa to obtain biomass pellet fuel; the rest of the mixture was exactly the same.

[0098] Comparative Example 14

[0099] A biomass pellet fuel and a preparation method thereof, wherein the specific steps of the preparation process are different from those of Example 2 in that: (1) 40 parts of corn cobs, 20 parts of corn stalks, 40 parts of cotton stalks, and 26.4 parts of tea seed cakes are crushed until they pass through a 200-mesh sieve to obtain crushed solid powder, which is then subjected to steam explosion treatment, and heat- and pressure-maintained treatment at a temperature of 135° C. and a pressure of 1.8 MPa for 10 minutes, and then discharged to room temperature and pressure within 25 to 30 seconds to obtain steam-exploded solid powder;

[0100] (3) During the stirring process, spray the moisture-proof agent dispersion onto the steam explosion solid powder, stir evenly and dry, then add 2.1 parts of a combustion aid composed of potassium permanganate, magnesium oxide and aluminum oxide in a mass ratio of 1.5:1:2.5, and mix evenly to obtain a mixed solid powder;

[0101] (4) The mixed solid powder was mixed with 4.2 parts of an adhesive composed of rosin and tower bottom heavy oil in a mass ratio of 3.5:1, and then stirred for 1 hour at a vacuum degree of 0.03 MPa and a temperature of 130°C. The mixture was then pressed into a cylindrical structure of 5 to 6 cm by a molding machine at a temperature of 135°C and a pressure of 65 MPa to obtain biomass pellet fuel; the rest of the mixture was exactly the same.

[0102] Performance test: The biomass pellet fuels prepared in Examples 1 to 6 and Comparative Examples 1 to 12 were subjected to performance tests, and the moisture content of the biomass fuels was measured under a relative humidity of 80%. The results are shown in Table 1.

[0103] Table 1 Biomass pellet fuel properties

[0104]

[0105]

[0106] It can be found from Table 1 above that Example 2 of the present invention, compared with Comparative Example 1, uses rapeseed cake to optimize the composition system of biomass pellet fuel and improve the calorific value and combustion efficiency of biomass pellet fuel; compared with Comparative Examples 2 to 5, the composition system of biomass pellet fuel can be further optimized by using montmorillonite and lignin. Montmorillonite is calcined by high-temperature and high-speed airflow, homogenized by high pressure, and then mixed with ethyl cellulose for ultrasonic treatment. Then, the moisture-proof agent is mixed with the biomass raw material and rapeseed cake, which has better barrier properties, so that the biomass pellet fuel has better moisture-proof effect and the fuel quality is improved. In addition, montmorillonite is mixed in the biomass raw material to promote the expansion of the particles, improve the combustion efficiency, and have high thermal efficiency. At the same time, ethyl cellulose and adhesive synergistically promote the raw materials to be more compact during combustion, the raw materials are not easy to disperse, and the combustion is more complete, thereby improving the fuel stability and calorific value; compared with Comparative Examples 6 to 8, the adhesive used is composed of rosin and The composition of the heavy oil at the bottom of the tower further optimizes the composition system of the biomass pellet fuel, so that the biomass particles can be closely combined together during the molding process to form a molded pellet fuel with stable structure, and the presence of rosin further improves the moisture resistance of the biomass pellet fuel, and the synergy between the rosin and the heavy oil at the bottom of the tower further improves the calorific value and combustion performance of the biomass pellet fuel; compared with comparative examples 9 to 11, the combustion aid used is composed of potassium permanganate, magnesium oxide and aluminum oxide, which further improves the composition system of the biomass pellet fuel, so that the biomass pellet fuel has higher combustion efficiency and stability, and improves the overall calorific value of the biomass pellet fuel; compared with comparative examples 12 to 14, the biomass raw material, rapeseed cake, moisture-proof agent and flame retardant are mixed together and then subjected to steam explosion treatment, so that the biomass pellet fuel has more excellent combustion efficiency and high thermal efficiency, while improving the overall calorific value of the biomass pellet fuel.

[0107] In summary, the biomass pellet fuel prepared in Examples 1 to 6 of the present invention uses corn cobs, corn stalks, and cotton stalks as biomass raw materials, mixes the biomass raw materials, moisture-proof agents, combustion aids, adhesives, and rapeseed cakes, optimizes the biomass pellet fuel composition system, effectively solves the problem of low combustion calorific value of biomass pellet fuel, and takes into account that the biomass pellet fuel has a more excellent moisture-proof effect, thereby improving the quality of the biomass pellet fuel.

[0108] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be embodied in other specific forms without departing from the spirit and essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0109] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A biomass pellet fuel, characterized in that: The raw materials include the following, calculated by weight percentage: 68-77% of biomass raw materials, 15-22% of tea seed cake, 2-4.5% of moisture-proof agent, 1.5-2.5% of combustion aid and 3-4% of adhesive; The combustion improver consists of potassium permanganate, magnesium oxide and aluminum oxide; The moisture-proof agent consists of montmorillonite and ethyl cellulose; The adhesive consists of rosin and tower bottom heavy oil.

2. A biomass pellet fuel according to claim 1, characterized in that: The biomass raw materials include the following raw materials, calculated by weight: 30 to 50 parts of corn cobs, 15 to 25 parts of corn stalks, and 35 to 45 parts of cotton stalks.

3. A method for preparing biomass pellet fuel according to any one of claims 1 to 2, characterized in that: The following steps are involved: (1) crushing corn cobs, corn stalks, cotton stalks, and tea seed cakes until they pass through a 200-mesh sieve to obtain crushed solid powder; (2) calcining the montmorillonite under high-temperature, high-speed airflow, stirring and mixing with deionized water and performing high-pressure homogenization to form a montmorillonite dispersion, and then adding ethyl cellulose for ultrasonic dispersion and stirring to obtain a moisture-proof agent dispersion; (3) During the stirring process, spraying a moisture-proof agent dispersion onto the crushed solid powder, stirring and drying, adding a combustion aid, mixing, and then steam explosion treatment to obtain steam explosion solid powder; (4) The steam explosion solid powder and the adhesive are mixed and then heated and stirred under vacuum, and then pressed and formed by a molding machine to obtain biomass pellet fuel.

4. The method for preparing a biomass pellet fuel according to claim 3, characterized in that: In step (2), the calcination treatment is carried out at a temperature of 1100-1150° C., an air flow velocity of 5-10 m / s, and a time of 15-25 min; and the high-pressure homogenization treatment is carried out at a pressure of 150-200 MPa and is circulated 10-15 times.

5. The method for preparing a biomass pellet fuel according to claim 3, characterized in that: In step (2), the ultrasonic dispersion treatment is carried out at an ultrasonic power of 400 to 500 W and for a time of 20 to 30 minutes.

6. The method for preparing biomass pellet fuel according to claim 3, characterized in that: In step (3), the steam explosion treatment is carried out at a temperature of 135-145° C. and a pressure of 1.8-2.2 MPa for 8-10 minutes, and then the steam is discharged to normal temperature and pressure within 25-30 seconds.

7. The method for preparing biomass pellet fuel according to claim 3, characterized in that: In step (4), the vacuum heating is carried out at a vacuum degree of 0.02 to 0.03 MPa, a temperature of 120 to 130° C., and a time of 1 to 2 h; Compression molding: Extrude into a 5-6 cm cylindrical shape at a temperature of 125-135°C and a pressure of 65-70 MPa.

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