Straw-containing fuel and preparation method thereof
By adding long-lasting stabilizers and optimizing the process, straw fuel with excellent weather resistance was prepared, solving the problem of easy weathering of straw and achieving efficient combustion and improved environmental friendliness.
Patent Information
- Application Number
- CN202511049432.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-29
- Publication Date
- 2025-11-21
AI Technical Summary
Straw is easily weathered, resulting in low fuel combustion efficiency, high pollution, and difficulties in storage and transportation, which are difficult to solve effectively with existing technologies.
By adding long-lasting stabilizers and optimizing the process, straw-containing fuels are prepared. The multi-hydroxyl structure forms a hydrogen bond network and a heterocyclic large conjugated system, which synergistically improves weather resistance, calorific value and environmental friendliness.
It improves the calorific value stability and environmental friendliness of fuel, reduces storage and transportation costs, and reduces pollution during combustion.
Smart Images
Figure CN120988752A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of solid fuel, in particular to a straw-containing fuel and a preparation method thereof. BACKGROUND
[0002] With the increasing global energy demand and the growing emphasis on environmental protection, developing clean and renewable energy has become a top priority. Straw, as a rich source of biomass, has great energy potential. However, the utilization rate of straw is still low, and a large amount of straw is discarded or burned at will, not only causing waste of resources, but also causing serious environmental pollution problems.
[0003] Straw itself has the characteristics of easy weathering, which brings many challenges to its development and utilization as fuel. In the natural environment, straw is mainly composed of cellulose, hemicellulose and lignin. These components will undergo complex physical and chemical changes under the action of factors such as light, temperature, humidity and microorganisms. For example, cellulose and hemicellulose will gradually degrade under the irradiation of ultraviolet light, causing the structure of straw to become loose, the strength to decrease, and the straw to be easily broken. At the same time, the moisture in the environment will penetrate into the inside of the straw, further accelerating its hydrolysis reaction, causing the chemical properties of the straw to change, reducing its calorific value and stability as fuel.
[0004] In addition, there are also some problems in the preparation and use of traditional straw fuel. In terms of preparation, due to the easy weathering characteristics of straw, its processing process needs to consider how to prevent the excessive oxidation and degradation of straw to ensure the quality and performance of the fuel. In the use process, the weathered straw fuel burns incompletely, producing a large amount of smoke and harmful gases, which poses a threat to air quality and human health. Moreover, due to the easy weathering of straw fuel, its storage and transportation are also limited to a certain extent, requiring special packaging and storage conditions, increasing the cost and management difficulty.
[0005] Therefore, developing a straw-containing fuel that can effectively solve the problem of easy weathering of straw and its preparation method has important practical significance for improving the utilization rate of straw, reducing environmental pollution and promoting the development of renewable energy. SUMMARY
[0006] The purpose of the present application is to solve the problems of easy weathering, low combustion efficiency and large pollution of straw-containing fuel in the prior art, and to provide a straw-containing fuel and a preparation method thereof. By adding long-acting stabilizers and other components and optimizing the process, the anti-weathering performance, calorific value and environmental friendliness of the fuel are improved.
[0007] To achieve the above object, the technical scheme adopted by the present application is as follows: a fuel containing straw, which is composed of the following raw materials in mass parts: 70-95 parts of straw, 3-15 parts of binder, 2-10 parts of combustion improver, 0.5-5 parts of sulfur-fixing agent, and 5.15 parts of long-acting stabilizer.
[0008] The long-acting stabilizer is a compound shown in the following structure:
[0009]
[0010] The R1 is selected from the group consisting of hydroxyl, methyl, methoxy, and propyl.
[0011] Further, the fuel containing straw is in the form of solid block.
[0012] Further, the straw is at least one of corn straw, wheat straw, or rice straw, which is crushed to a particle size of 0.5-3 mm and has a water content of ≤15%.
[0013] Further, the binder is at least one of sodium carboxymethyl cellulose, modified starch, or lignin sulfonate.
[0014] Further, the combustion improver is composed of potassium nitrate and iron oxide in a mass ratio of 1:0.2-0.8.
[0015] Further, the sulfur-fixing agent is at least one of calcium carbonate or magnesium hydroxide.
[0016] Further, the long-acting stabilizer is at least one of the following compounds:
[0017]
[0018] A preparation method of a fuel containing straw, which comprises the following steps:
[0019] S1. Soaking the straw in a 5%-10% sodium hydroxide solution for 1-2 h, washing with water until neutral, and drying to obtain pretreated straw;
[0020] S2. Mixing the pretreated straw, binder, combustion improver, sulfur-fixing agent, and long-acting stabilizer in a mixer at a rotation speed of 300-500 r / min for 15-30 min to obtain a mixture;
[0021] S3. Feeding the mixture into a ring mode molding machine, extruding and molding at a temperature of 150-180℃ and a pressure of 30-50 MPa, aging in a humidity environment of 40-60% for 24-48 h, and drying to obtain a fuel containing straw.
[0022] Further, the drying in S1 and S3 is first carried out at 80-100℃ until the water content is 25%-30%, and then carried out at 50-60℃ until the water content is ≤15%.
[0023] Further, the S2 is carried out under a nitrogen atmosphere.
[0024] Further, the adhesive in the binder of the preparation method is configured as a 15% ethanol solution when used.
[0025] The long-acting stabilizer of the present application improves the weather resistance, heat value stability and environmental protection of the straw-containing fuel through the synergistic effect of the multi-hydroxyl group and the heterocyclic large conjugate system in its structural characteristics, and the specific mechanism is as follows: the multi-hydroxyl structure forms a hydrogen bond network through strong hydrophilicity, locks the water in the fuel, inhibits the hydrolysis of straw cellulose and the crushing of the particle size caused by water infiltration, and at the same time enhances the interfacial bonding force with the binder through intermolecular hydrogen bonds, improves the mechanical strength of the solid block fuel, and resists the expansion and cracking caused by humidity changes; the heterocyclic large conjugate structure absorbs ultraviolet rays (200-400 nm) through π→π / n→π electron transition, converts light energy into heat energy to prevent ultraviolet degradation of straw cellulose, and uses the electron delocalization property to quench active oxygen free radicals, interrupt the oxidation chain reaction, and reduce SO2 emissions in cooperation with the sulfur fixation agent, and the molecular rigidity also maintains the structural integrity in the process of high-temperature extrusion molding and aging. The two structures synergistically form a weather-resistant multi-barrier under the preparation condition of nitrogen atmosphere, solve the comprehensive degradation path of light / humidity / oxidation / microorganisms through the water regulation, UV protection and free radical capture mechanism, and finally realize the stability of fuel heat value, the reduction of combustion pollution and sustainable storage and transportation.
[0026] The present application realizes the synergistic effect of the components (straw 70-95 parts, binder 3-15 parts, combustion improver 2-10 parts, sulfur fixation agent 0.5-5 parts and long-acting stabilizer) in a specific ratio under the preparation process, fundamentally improves the weather resistance, combustion efficiency and environmental protection of the fuel: the long-acting stabilizer as the core, its multi-hydroxyl structure locks the water through the hydrogen bond network and strengthens the interfacial bonding with the binder, inhibits the hydrolysis of straw and the crushing of the particle size; the heterocyclic large conjugate system absorbs ultraviolet rays (200-400 nm) and quenches free radicals, blocks the photo-oxidation and microbial degradation path. After pretreatment of the straw to remove lignin, the hydrogen bond combination with the long-acting stabilizer is enhanced. The binder forms a dense network, which synergistically enhances the mechanical strength with the long-acting stabilizer and resists the expansion and cracking caused by humidity changes. The combustion improver catalyzes combustion and reduces the generation of carbon monoxide in cooperation with the free radical quenching mechanism of the long-acting stabilizer. The sulfur fixation agent and the long-acting stabilizer capture sulfur radicals together, chemically fix SO2 and reduce emissions. In the process, the nitrogen atmosphere inhibits oxidation, extrusion molding strengthens the block structure, and staged drying prevents crushing in cooperation with the water locking mechanism of the long-acting stabilizer. Finally, a multi-protection is formed: weather resistance (moisture / UV / oxidation barrier), efficient combustion (complete combustion catalysis), low pollution, realizing the long-term stability, high heat value and environmental protection of the fuel.
[0027] Compared with the prior art, the present application has the following advantages:
[0028] 1. Heat value and stability improvement: In the examples containing long-acting stabilizers, the heat value of the fuel as a whole is maintained at a high level, and its aging heat value retention rate also shows significant stability advantages, indicating that the long-acting stabilizer plays a key role in improving the initial energy efficiency and long-term anti-aging ability of the fuel.
[0029] 2. Environmental performance improvement: The present application can effectively capture sulfur radicals and reduce sulfur dioxide emissions through the synergistic effect of long-acting stabilizers and sulfur fixation agents, thereby reducing environmental pollution during the combustion process and achieving environmental performance of the fuel.
[0030] 3. Improved convenience of storage and transportation: Since the long-acting stabilizer can significantly improve the weathering resistance of the fuel, special packaging and storage conditions are no longer required during storage and transportation, reducing costs and management difficulties. BRIEF DESCRIPTION OF DRAWINGS
[0031] Figure 1 NMR chart of the long-acting stabilizer 1 described in the present application. DETAILED DESCRIPTION
[0032] The technical solutions of the present application will be described clearly and completely below in combination with the drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application.
[0033] Preparation Example 1
[0034] Synthesis of long-acting stabilizer 1:
[0035]
[0036] First step feeding: Under a nitrogen atmosphere, 15 g of raw material 1, 11.57 g of raw material 2, 8.00 g of anhydrous sodium carbonate and 200 g of toluene solution were sequentially added to the reaction system, stirred uniformly, replaced with nitrogen twice, 1.34 g of tetrakis(triphenylphosphine)palladium was added to the reaction system, replaced with nitrogen twice again, heated to 95°C to reflux for 10 hours.
[0037] First step post-processing: After the reaction was completed, the organic phase was retained by filtering with a silica gel cake, and was spin-dried. Silica gel column chromatography was performed using a mixture of petroleum ether and ethyl acetate as the eluent, and was spin-dried to obtain 16.67 g of intermediate 1.
[0038] M / Z (M+H + ) of intermediate 1: 739; actual molecular mass of intermediate 1: 738.
[0039] The second step: under the nitrogen atmosphere, 16.67 g of intermediate 1, 5.50 g of raw material 3, 6.24 g of sodium carbonate, 0.08 g of target carbon, 0.30 g of triphenylphosphine and 200 g of toluene were added into the reaction system, stirred uniformly, heated to 110℃, and refluxed for 12 h.
[0040] The second step post-treatment: after the reaction was completed, the temperature was slightly reduced, and the silica gel cake was used for filtration, spin-drying, and silica gel column chromatography was performed, using a mixture of petroleum ether and ethyl acetate as the eluent, spin-drying, to obtain 15.66 g of long-acting stabilizer 1.
[0041] M / Z (M+H + ) of long-acting stabilizer 1: 861; actual molecular mass of long-acting stabilizer 1: 860.
[0042] HNMR of long-acting stabilizer 1 1 HNMR- deuterated chloroform, Figure 1 : δ 8.57 (m, 1H), 8.22 (dd, 1H), 8.10 (d, 1H), 8.02-7.84 (m, 2H), 7.78-7.63 (m, 3H), 7.63-7.50 (m, 2H), 7.42 (dd, 1H), 7.31 (m, 1H), 7.05 (dd, 3H), 6.86 (d, 1H), 6.74 (s, 2H), 5.95 (m, 1H), 5.17 (m, 1H), 5.08-4.94 (m, 3H), 4.46 (dd, 2H), 4.33 (t, 1H), 4.16 (dd, 1H), 4.01-3.61 (m, 4H), 3.53 (m, 1H), 3.38 (m, 2H), 2.20 (s, 3H), 1.69 (s, 6H).
[0043] Preparation examples 2-4
[0044] Long-acting stabilizers 2-4 were prepared in preparation examples 2-4, respectively, by referring to the preparation method of preparation example 1, replacing the raw material 3 therein, and the rest being the same as preparation example 1. See Table 1 for details.
[0045] Table 1.
[0046]
[0047] Example 1
[0048] Preparation of a fuel containing straw:
[0049] 1. Raw material composition:
[0050] Straw: 85 parts by mass (wheat straw, crushed to a particle size of 1.5 mm, water content ≤10%);
[0051] Binder: 8 parts by mass (sodium carboxymethyl cellulose);
[0052] Combustion-supporting agent: 6 parts by mass (consisting of potassium nitrate and iron oxide in a mass ratio of 1:0.5, i.e., 4 parts by mass of potassium nitrate and 2 parts by mass of iron oxide);
[0053] Sulfur-fixing agent: 2 parts by mass (calcium carbonate);
[0054] Long-acting stabilizer: 5.15 parts by mass (long-acting stabilizer 1).
[0055] 2. Preparation method:
[0056] S1. Wheat straw (pulverized to a particle size of 1.5 mm) was immersed in an 8% sodium hydroxide solution and soaked at room temperature for 1.5 hours. Subsequently, it was repeatedly washed with deionized water until neutral (pH = 7). The drying process was divided into two stages: first, drying at 90°C until the moisture content was 28%, and then drying at 55°C until the moisture content was ≤10%, obtaining pretreated straw;
[0057] S2. The pretreated straw, the binder sodium carboxymethyl cellulose (prepared as a 15% ethanol solution before use), the combustion-supporting agent (a mixture of potassium nitrate and iron oxide), the sulfur-fixing agent calcium carbonate, and the long-acting stabilizer 1 were added to a high-speed mixer under a nitrogen atmosphere. Mixing was carried out at a speed of 400 r / min for 20 minutes to ensure uniform dispersion of the components, obtaining a mixture;
[0058] S3. The mixture was fed into a ring-mode molding machine and extruded at a temperature of 165°C and a pressure of 40 MPa to form solid block fuel (size: 50 mm x 50 mm x 30 mm). Subsequently, the finished product, straw-containing fuel, was aged in an environment with a humidity of 50% for 36 hours.
[0059] Examples 2-4
[0060] A straw-containing fuel was prepared according to the preparation method of Example 1, in which the long-acting stabilizer was replaced with long-acting stabilizers 2-4 in turn, and the rest remained the same as in Example 1.
[0061] Comparative Example 1
[0062] A straw-containing fuel was prepared according to the preparation method of Example 1, in which the long-acting stabilizer was replaced with antioxidant 1010, and the rest remained the same as in Example 1.
[0063] Antioxidant 1010 is a commonly used antioxidant stabilizer in industry.
[0064] Comparative Example 2
[0065] A kind of preparation of straw-containing fuel, with reference to the preparation method of example 1, long-acting stabilizer in it is replaced with comparative compound 1, the rest remains the same as example 1.
[0066] Comparative compound 1 is:
[0067] Comparative example 3
[0068] A kind of preparation of straw-containing fuel, with reference to the preparation method of example 1, long-acting stabilizer in it is not added, the rest remains the same as example 1.
[0069] Performance test:
[0070] 1. Calorific value: a kind of straw-containing fuel prepared in example and comparative example is placed in Shanghai Mitan electromechanical MTZW-A4 type full-automatic calorimeter, and the calorific value of sample combustion is measured after oxygenation. Data are shown in Table 2.
[0071] 2. Aging calorific value retention rate: a kind of straw-containing fuel prepared in example and comparative example is placed in 80℃, oxygen concentration 30%, UV-A light source irradiation environment for 200h, and the calorific value is tested, and the aging calorific value retention rate is calculated. Data are shown in Table 2.
[0072] Table 2.
[0073] Calorific value (M / kg) Aged calorific value retention rate (%) Example 1 18.5 90 Example 2 18.4 89 Example 3 18.6 91 Example 4 18.3 88 Comparative Example 1 17.0 78 Comparative Example 2 16.8 75 Comparative Example 3 16.5 70
[0074] In the example containing long-acting stabilizer, the calorific value is maintained at a higher level as a whole, and the aging calorific value retention rate also shows significant stability advantage; in contrast, the calorific value of comparative example (such as using conventional antioxidant, replacing compound or not adding long-acting stabilizer) is generally low, and the aging calorific value retention rate shows a significant downward trend. This shows that the long-acting stabilizer plays a key role in improving the initial energy efficiency and long-term anti-aging ability of fuel, and overall highlights its positive impact on the stability and durability of fuel calorific value, and the slight fluctuations between examples may be due to the slight difference in the structure of long-acting stabilizer, but all examples are better than comparative example, highlighting the core contribution of the component.
[0075] Although the embodiments of the present application have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, replacements and variations can be made to these embodiments without departing from the principles and spirits of the present application, and the scope of the present application is defined by the appended claims and their equivalents.
Claims
1. A straw-containing fuel, characterized in that, It is composed of the following raw materials in parts by weight: 70-95 parts straw, 3-15 parts binder, 2-10 parts combustion improver, 0.5-5 parts sulfur fixative, and 5.15 parts long-lasting stabilizer; The long-acting stabilizer has the structure shown in Formula 1: R1 is selected from: hydroxyl, methyl, methoxy, propyl.
2. The straw-containing fuel according to claim 1, characterized in that, The aforementioned straw-containing fuel is in solid block form.
3. The straw-containing fuel according to claim 1, characterized in that, The straw is at least one of corn straw, wheat straw or rice straw, crushed to a particle size of 0.5-3 mm and a moisture content of ≤15%.
4. The straw-containing fuel according to claim 1, characterized in that, The binder is at least one of sodium carboxymethyl cellulose, modified starch, or lignin sulfonate.
5. A straw-containing fuel according to claim 1, characterized in that, The combustion aid is composed of potassium nitrate and iron oxide in a mass ratio of 1:0.2-0.
8.
6. A straw-containing fuel according to claim 1, characterized in that, The sulfur-fixing agent is at least one of calcium carbonate or magnesium hydroxide.
7. A straw-containing fuel according to claim 1, characterized in that, The long-acting stabilizer is at least one of the compounds shown in the following structures:
8. A method for preparing a straw-containing fuel according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Soak straw in a 5%-10% sodium hydroxide solution for 1-2 hours, wash with water until neutral, and then dry to obtain pretreated straw; S2. The pretreated straw, binder, combustion aid, sulfur fixative and long-lasting stabilizer are mixed in a mixer at a speed of 300-500 r / min for 15-30 min to obtain a mixture; S3. The mixture is fed into a ring molding machine and extruded at a temperature of 150-180℃ and a pressure of 30-50MPa. It is then aged in an environment with a humidity of 40-60% for 24-48 hours and dried to obtain a straw-containing fuel.
9. A method for preparing straw-containing fuel according to claim 8, characterized in that, The drying in S1 and S3 involves first drying at 80-100℃ to a moisture content of 25%-30%, and then drying at 50-60℃ to a moisture content of ≤15%.
10. A method for preparing straw-containing fuel according to claim 8, characterized in that, The S2 process is carried out under a nitrogen atmosphere.