A process for producing biomass fuel using bio-fibers

Abstract

This invention belongs to the field of sustainable biofuel production technology, specifically relating to a process for producing biomass fuel using biocellulose. It includes the following steps: S1: pretreatment of biocellulose raw materials; S2: biochemical conversion synergistic catalytic conversion and deoxygenation to obtain crude biofuel; S3: nano-modification and product refining to obtain biomass fuel. This invention employs a segmented hydrolysis-separation technology, utilizing high-temperature liquid water self-ionization to hydrolyze cellulose with maleic acid to generate glucose, forming a physical chain-opening-chemical bond-breaking synergistic mode, reducing S / Cl pollution. Coupled with Ni / Al2O3-SiO2 hydrogenation and HZSM-5 molecular sieve shape-selective catalysis, oxygen-containing gases are converted into saturated alkanes. Sodium lignin sulfonate amphiphilic structures construct a stable carbon nanotube-hydrocarbon chain dispersion system, combined with high-pressure homogeneous cavitation effects to form a nano-core-shell structure. The oxygen-containing polar molecules of biofuel and nanomaterials synergistically improve combustion rate and energy release uniformity.

Description

Technical Field

[0001] This invention belongs to the field of sustainable biofuel production technology, specifically relating to a process for producing biomass fuel using bio-fibers. Background Technology

[0002] With the dual pressures of increasing global energy demand and depletion of fossil fuel resources, biomass energy has received widespread attention as a renewable, low-carbon alternative. Current biomass fuel production technologies mainly revolve around three major directions: oil transesterification, starch saccharification and fermentation, and lignocellulose conversion. Among these, biodiesel technology using waste oil as raw material and ethanol gasoline technology using corn and sugarcane as raw materials have achieved industrial application. However, these technologies generally face problems such as limited raw material sources and conflicts with food security. Currently, mainstream biomass fuel preparation technologies include pyrolysis liquefaction, gasification synthesis, enzymatic fermentation, and transesterification. For example, rapid pyrolysis technology decomposes biomass into bio-oil under high-temperature, anaerobic conditions. However, bio-oil produced by traditional processes generally suffers from high oxygen content, strong acidity, low calorific value, and poor stability, easily leading to polymerization reactions and the formation of gum deposits during storage, severely limiting its direct application as fuel. In recent years, lignocellulose biomass, due to its widespread presence in agricultural waste (such as straw and rice husks), forestry processing residues (such as sawdust and bark), and energy crops (such as switchgrass and miscanthus), has gradually become the focus of research on second-generation biofuels. However, the complex supramolecular structure of lignocellulose makes it difficult to directly convert. Existing pretreatment technologies, such as dilute acid hydrolysis, steam explosion, and organic solvent separation, can disrupt the lignin-hemicellulose cross-linking network, but they generally suffer from high energy consumption, large chemical reagent consumption, and pretreatment wastewater pollution. In the conversion stage, the enzymatic hydrolysis-fermentation route is limited by the high cost of cellulase and the tolerance of inhibitors. While rapid pyrolysis in the thermochemical conversion route can directly produce bio-crude oil, the product has defects such as high oxygen content, low calorific value, and strong corrosivity, requiring catalytic hydrodeoxygenation to meet automotive fuel standards, resulting in high overall costs. Therefore, given these problems, developing an environmentally friendly and efficient biomass fuel production process is extremely necessary. Summary of the Invention

[0003] In view of the shortcomings of the prior art, the purpose of this invention is to provide a process for producing biomass fuel using bio-fibers.

[0004] The technical effects described in this invention are achieved through the following technical solution: a process for producing biomass fuel using bio-cellulose, comprising the following steps:

[0005] S1: Pretreatment of bio-fiber raw materials;

[0006] S2: Biochemical conversion synergistically with catalytic conversion and deoxygenation to obtain crude biofuel;

[0007] S3: Nano-modification and fuel refining to obtain biomass fuel;

[0008] Preferably, in step S1, the specific steps of the pretreatment of the bio-cellulose raw material are as follows:

[0009] S101: Dry the straw at 80-100°C until the moisture content is <10%, then crush it to a particle size of 0.5-2mm to obtain biomass raw material; treat the biomass raw material at 180-200°C and 1.5-2MPa for 10-20 minutes, then add 2-3% maleic acid and deionized water, and treat at 150-160°C for 30-60 minutes to obtain hydrolysate;

[0010] S102: Centrifuge the hydrolysate prepared in step S101 at 5000 rpm for 10-15 min, filter, add 1-2% activated carbon, adsorb for 1-2 h, filter with a 0.2 μm ceramic membrane, and concentrate under vacuum at 60℃ to a sugar concentration of 100-120 g / L to obtain pretreated bio-fiber.

[0011] Preferably, in step S2, the specific steps of the biochemical transformation synergistic catalytic transformation and deoxygenation are as follows:

[0012] S201: The pretreated bio-fiber prepared in step S102 is mixed with continuously introduced hydrogen gas and preheated to 120°C at a heating rate of 2-3°C / min. Then, 6% of the mass of the pretreated bio-fiber is added to carry out primary catalytic deoxygenation using a nickel-based catalyst Ni / Al2O3-SiO2 for primary catalytic deoxygenation.

[0013] S202: After completing the catalytic deoxygenation operation in step S201, perform low-temperature alkylation treatment and high-temperature deoxygenation refining stage treatment; after the treatment is completed, the reaction products are separated into unreacted hydrogen and liquid crude fuel by multi-stage condensation at 20°C, 10°C and -10°C, and the liquid crude fuel is distilled under atmospheric pressure, and the components with boiling range of 30 to 100°C are collected in stages to obtain crude biofuel.

[0014] Preferably, in step S201, the nickel-based catalyst Ni / Al2O3-SiO2 is an existing catalyst that can be directly purchased through conventional channels;

[0015] Preferably, in step S201, the primary catalytic deoxygenation treatment parameters include: fixed-bed continuous reactor, 160-210°C, pressure 4MPa, residence time 30-60min;

[0016] Preferably, in step S202, the parameters for the low-temperature alkylation treatment include: substrate mass of 6% nickel-based catalyst Ni / HZSM-5, temperature of 210–230°C, pressure of 3.5–4 MPa, and residence time of 60–90 min;

[0017] Preferably, in step S202, the parameters for the high-temperature deoxygenation and refining process include: substrate mass of 8% phosphorus-modified nickel-based catalyst Ni-P / HZSM-5, temperature of 250-270°C, pressure of 3.5 MPa, hydrogen circulation rate of 200-300 L / h, and time of 30-45 min.

[0018] Preferably, in step S202, the nickel-based catalyst Ni / HZSM-5 is an existing catalyst that can be directly purchased through conventional channels;

[0019] Preferably, in step S202, the specific preparation steps of the phosphorus-modified nickel-based catalyst Ni-P / HZSM-5 are as follows:

[0020] S301: Calcine HZSM-5 molecular sieve at 550℃ for 4-5 hours, then mix with 1M ammonium nitrate solution, stir at 80℃ for 2-3 hours, filter, repeat stirring 3 times, centrifuge and filter, wash until neutral, and dry at 110℃ for 8-12 hours to obtain pretreated HZSM-5.

[0021] S302: The pretreated HZSM-5 prepared in step S301 is immersed in a 0.1-0.3M nickel nitrate solution, stirred at 80°C for 4-5 hours, centrifuged and filtered, dried at 110°C for 8-12 hours, then heated to 500°C in a tube furnace at a rate of 5°C / min, calcined in air atmosphere for 4 hours, then switched to H2 at a flow rate of 50 mL / min, and reduced at 450°C for 3 hours to obtain Ni / HZSM-5;

[0022] S303: The Ni / HZSM-5 prepared in step S302 is mixed with 30wt% phosphoric acid solution, allowed to stand at room temperature for 12h, dried at 110℃ for 8-12h, then heated to 550℃ in a muffle furnace at a rate of 2℃ / min and calcined in air atmosphere for 4h, followed by hydrothermal aging treatment at 600℃ in 100% water vapor atmosphere for 8-12h to obtain Ni-P / HZSM-5;

[0023] Preferably, in step S301, the ratio of the amount of HZSM-5 molecular sieve to ammonium nitrate solution is 1g:10-12mL;

[0024] Preferably, in step S302, the ratio of the amount of pretreated HZSM-5 to nickel nitrate solution is 1g:5mL;

[0025] Preferably, in step S303, the ratio of Ni / HZSM-5 to 30wt% phosphoric acid solution is 1g:0.3-0.5mL;

[0026] Preferably, in step S3, the specific steps of nano-modification and fuel refining are as follows:

[0027] S401: Mix carbon nanotubes and sodium lignosulfonate in a certain proportion, add them to deionized water, and sonicate them at 200-300W, 40kHz, and 20-30min to obtain nano slurry.

[0028] S402: Mix the crude biofuel prepared in step S402 and the nano slurry prepared in step S401 in a certain proportion, treat at 8000-10000 rpm for 20-30 min, and then homogenize at 40-50 MPa 3 times.

[0029] S403: After completing the homogenization process in step S402, hydrocarbon components with a boiling range of 30-80°C are collected in stages at a pressure of 10-15 kPa to obtain biomass fuel.

[0030] Preferably, in step S401, the ratio of the amount of carbon nanotubes, sodium lignosulfonate, and deionized water is 2-3g:5-6g:100mL.

[0031] Preferably, in step S402, the volume ratio of the crude biofuel and the nano-slurry is 100-120:1.

[0032] The beneficial effects of this invention are as follows:

[0033] This invention employs a segmented hydrolysis and selective component separation process. First, high-temperature liquid water pretreatment utilizes the self-ionization properties of water to selectively break the β-1,4 glycosidic bonds of hemicellulose under extremely low chemical additive conditions, releasing pentose sugars such as xylose while preserving the integrity of the cellulose skeleton, creating a loose structure for subsequent acid catalysis. Then, the mild acidity of bio-based maleic acid is used to attack the amorphous regions of cellulose, directionally generating glucose and avoiding excessive sugar degradation or lignin condensation caused by strong acids, thus controlling the product impurity profile from the source. The two-stage treatment forms a synergistic mode of physical chain opening and chemical bond breaking, effectively avoiding the introduction of non-C / H / O elements such as sulfur (S) and chlorine (Cl), ensuring product purity, and enabling the cascade utilization of hemicellulose and cellulose, providing highly active, low-inhibitor sugar solution feedstock for downstream catalytic conversion. By leveraging the hydrogenation activity of Ni / Al2O3-SiO2 and the shape-selective effect of HZSM-5 molecular sieves, oxygen-containing intermediates are directionally converted into saturated alkanes. Through the synergistic effect of high-temperature liquid water pretreatment and weak acid hydrolysis, hemicellulose and cellulose are directionally deconstructed, providing a highly active sugar solution for catalytic deoxygenation. A two-stage nickel-based catalyst, through the synergistic effect of low-temperature protection and high-temperature deep deoxygenation, balances catalyst lifetime and deoxygenation efficiency. In subsequent processes, sodium lignosulfonate, with its amphiphilic structure, embeds itself at one end into the defect sites on the surface of carbon nanotubes, while the other end forms a hydrophobic interaction with the fuel hydrocarbon chain, constructing a stable dispersion system and solving the problem of nanoparticle agglomeration. After removing light impurities by vacuum distillation, the cavitation effect generated by high-pressure homogenization further breaks down the nano-aggregates, allowing the modifier to be uniformly embedded in the intermolecule gaps of the fuel, forming a nano-core-hydrocarbon shell composite structure. Furthermore, the high thermal conductivity of nanomaterials accelerates fuel gasification, while the oxygen-containing polar molecules of biofuel enhance the wettability of the nano-interface; both synergistically improve the combustion rate and energy release uniformity. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only for this invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 These are biofuel yield diagrams prepared by the processes of Examples 1-3 and Comparative Examples 1-4 of this invention. Detailed Implementation

[0036] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be noted that, unless otherwise specified, the raw materials involved in the present invention are all purchased through conventional commercial channels.

[0037] Example 1: A process for producing biomass fuel using biocellulose, comprising the following steps:

[0038] S1: Pretreatment of bio-fiber raw materials;

[0039] S101: Dry 1000g of straw at 90°C until the moisture content is <10%, then crush it to a particle size of 1mm to obtain biomass raw material; treat the biomass raw material at 190°C and 1.8MPa for 15min, then add 25g of maleic acid and 500mL of deionized water, and treat at 155°C for 50min to obtain hydrolysate;

[0040] S102: The hydrolysate prepared in step S101 was centrifuged at 5000 rpm for 12 min, filtered, 1.5% activated carbon was added, adsorption was performed for 1.5 h, filtered through a 0.2 μm ceramic membrane, and concentrated under vacuum at 60 °C to a sugar concentration of 100 g / L to obtain pretreated bio-fiber.

[0041] S2: Biochemical conversion synergistically with catalytic conversion and deoxygenation to obtain crude biofuel;

[0042] S201: Mix 200 mL of pretreated bio-fiber prepared in step S102 with continuously introduced hydrogen gas, preheat to 120 °C at a heating rate of 2.5 °C / min, add 6% by weight of substrate mass of nickel-based catalyst Ni / Al2O3-SiO2 for primary catalytic deoxygenation, in a fixed-bed continuous reactor at 185 °C, pressure 4 MPa, residence time 45 min;

[0043] S202: After completing the catalytic deoxygenation operation in step S201, a low-temperature alkylation treatment is performed using a substrate of 6% nickel-based catalyst Ni / HZSM-5, at a temperature of 220°C, a pressure of 3.8 MPa, and a residence time of 75 min. A high-temperature deoxygenation and refining stage is then performed using a substrate of 8% phosphorus-modified nickel-based catalyst Ni-P / HZSM-5, at a temperature of 260°C, a pressure of 3.5 MPa, a hydrogen circulation rate of 250 L / h, and a time of 38 min. After the treatment, the reaction products are subjected to multi-stage condensation separation at 20°C, 10°C, and -10°C to separate unreacted hydrogen and liquid crude fuel. The liquid crude fuel is then subjected to atmospheric distillation, and the components with a boiling range of 30–100°C are collected in stages to obtain crude biofuel.

[0044] The specific preparation steps of the phosphorus-modified nickel-based catalyst Ni-P / HZSM-5 are as follows:

[0045] S301: 10g of HZSM-5 molecular sieve was calcined at 550℃ for 4.5h, then mixed with 100mL of 1M ammonium nitrate solution, stirred at 80℃ for 2.5h, filtered, and the stirring treatment was repeated 3 times. After centrifugation and filtration, the mixture was washed until neutral and dried at 110℃ for 8h to obtain pretreated HZSM-5.

[0046] S302: 10g of pretreated HZSM-5 prepared in step S301 was immersed in 50mL of 0.2M nickel nitrate solution, stirred at 80℃ for 4h, centrifuged and filtered, dried at 110℃ for 8h, then heated to 500℃ in a tube furnace at a rate of 5℃ / min and calcined in air atmosphere for 4h, then switched to H2 at a flow rate of 50mL / min and reduced at 450℃ for 3h to obtain Ni / HZSM-5;

[0047] S303: Mix 10g of Ni / HZSM-5 prepared in step S302 with 4mL of 30wt% phosphoric acid solution, let stand at room temperature for 12h, dry at 110℃ for 8h, then heat to 550℃ in a muffle furnace at a rate of 2℃ / min, calcine in air atmosphere for 4h, and then hydrothermally age at 600℃ in 100% water vapor atmosphere for 10h to obtain Ni-P / HZSM-5;

[0048] S3: Nano-modification and fuel refining to obtain biomass fuel;

[0049] S401: Mix 0.3g of carbon nanotubes with 0.6g of sodium lignosulfonate in a certain proportion, add to 10mL of deionized water, and sonicate at 300W, 40kHz, and 20min to obtain nano slurry.

[0050] S402: Mix 200 mL of crude biofuel prepared in step S402 and 2 mL of nano slurry prepared in step S401 in proportion, process at 8000 rpm for 30 min, and then homogenize at 50 MPa 3 times.

[0051] S403: After completing the homogenization process in step S402, hydrocarbon components with a boiling range of 30-80°C are collected in stages at a pressure of 15 kPa to obtain biomass fuel.

[0052] Example 2: A process for producing biomass fuel using biocellulose, comprising the following steps:

[0053] S1: Pretreatment of bio-fiber raw materials;

[0054] S101: Dry 1000g of straw at 80°C until the moisture content is <10%, then crush it to a particle size of 0.5mm to obtain biomass raw material; treat the biomass raw material at 180°C and 1.5MPa for 10min, then add 20g of maleic acid and 200mL of deionized water, and treat at 150°C for 30min to obtain hydrolysate;

[0055] S102: The hydrolysate prepared in step S101 is centrifuged at 5000 rpm for 10 min, filtered, 1% activated carbon is added, adsorption is performed for 1 h, filtered through a 0.2 μm ceramic membrane, and concentrated under vacuum at 60 °C to a sugar concentration of 120 g / L to obtain pretreated bio-fiber.

[0056] S2: Biochemical conversion synergistically with catalytic conversion and deoxygenation to obtain crude biofuel;

[0057] S201: Mix 200 mL of pretreated bio-fiber prepared in step S102 with continuously introduced hydrogen gas, preheat to 120 °C at a heating rate of 2 °C / min, add 6% by weight of substrate mass of nickel-based catalyst Ni / Al2O3-SiO2 for primary catalytic deoxygenation, in a fixed-bed continuous reactor at 160 °C, pressure 4 MPa, residence time 30 min.

[0058] S202: After completing the catalytic deoxygenation operation in step S201, a low-temperature alkylation treatment is performed using a substrate of 6% nickel-based catalyst Ni / HZSM-5, at a temperature of 210°C, a pressure of 3.5 MPa, and a residence time of 60 min. A high-temperature deoxygenation and refining stage is then performed using a substrate of 8% phosphorus-modified nickel-based catalyst Ni-P / HZSM-5, at a temperature of 250°C, a pressure of 3.5 MPa, a hydrogen circulation rate of 200 L / h, and a time of 30 min. After the treatment, the reaction products are subjected to multi-stage condensation at 20°C, 10°C, and -10°C to separate unreacted hydrogen and liquid crude fuel. The liquid crude fuel is then subjected to atmospheric distillation, and the components with a boiling range of 30–100°C are collected in stages to obtain crude biofuel.

[0059] The specific preparation steps of the phosphorus-modified nickel-based catalyst Ni-P / HZSM-5 are as follows:

[0060] S301: 10g of HZSM-5 molecular sieve was calcined at 550℃ for 4h, then mixed with 110mL of 1M ammonium nitrate solution, stirred at 80℃ for 2h, filtered, and the stirring treatment was repeated 3 times. After centrifugation and filtration, the mixture was washed until neutral and dried at 110℃ for 10h to obtain pretreated HZSM-5.

[0061] S302: 10g of pretreated HZSM-5 prepared in step S301 was immersed in 50mL of 0.1M nickel nitrate solution, stirred at 80℃ for 4.5h, centrifuged and filtered, dried at 110℃ for 10h, then heated to 500℃ in a tube furnace at a rate of 5℃ / min and calcined in air atmosphere for 4h, then switched to H2 at a flow rate of 50mL / min and reduced at 450℃ for 3h to obtain Ni / HZSM-5;

[0062] S303: Mix 10g of Ni / HZSM-5 prepared in step S302 with 3mL of 30wt% phosphoric acid solution, let stand at room temperature for 12h, dry at 110℃ for 10h, then heat to 550℃ in a muffle furnace at a rate of 2℃ / min, calcine in air atmosphere for 4h, and then hydrothermally age at 600℃ for 12h in 100% water vapor atmosphere to obtain Ni-P / HZSM-5;

[0063] S3: Nano-modification and fuel refining to obtain biomass fuel;

[0064] S401: Mix 0.2g of carbon nanotubes with 0.5g of sodium lignosulfonate in a certain proportion, add to 10mL of deionized water, and sonicate at 200W, 40kHz and 25min to obtain nano slurry.

[0065] S402: Mix 120 mL of crude biofuel prepared in step S402 and 1 mL of nano slurry prepared in step S401 in proportion, process at 8000 rpm for 25 min, and then homogenize at 40 MPa 3 times.

[0066] S403: After completing the homogenization process in step S402, hydrocarbon components with a boiling range of 30-80°C are collected in stages at a pressure of 10 kPa to obtain biomass fuel.

[0067] Example 3: A process for producing biomass fuel using bio-cellulose, comprising the following steps:

[0068] S1: Pretreatment of bio-fiber raw materials;

[0069] S101: Dry 1000g of straw at 100°C until the moisture content is <10%, then crush it to a particle size of 2mm to obtain biomass raw material; treat the biomass raw material at 180-200°C and 2MPa for 20min, then add 30g of maleic acid and 200mL of deionized water, and treat at 160°C for 60min to obtain hydrolysate;

[0070] S102: The hydrolysate prepared in step S101 was centrifuged at 5000 rpm for 15 min, filtered, 2% activated carbon was added, adsorption was performed for 2 h, filtered through a 0.2 μm ceramic membrane, and concentrated under vacuum at 60 °C to a sugar concentration of 110 g / L to obtain pretreated bio-fiber.

[0071] S2: Biochemical conversion synergistically with catalytic conversion and deoxygenation to obtain crude biofuel;

[0072] S201: Mix 200 mL of pretreated bio-fiber prepared in step S102 with continuously introduced hydrogen gas, preheat to 120 °C at a heating rate of 3 °C / min, add 6% by weight of substrate mass of nickel-based catalyst Ni / Al2O3-SiO2 for primary catalytic deoxygenation, fixed bed continuous reactor at 210 °C, pressure 4 MPa, residence time 60 min;

[0073] S202: After completing the catalytic deoxygenation operation in step S201, a low-temperature alkylation treatment is performed using a substrate of 6% nickel-based catalyst Ni / HZSM-5, at a temperature of 230°C, a pressure of 4 MPa, and a residence time of 90 min. A high-temperature deoxygenation and refining stage is then performed using a substrate of 8% phosphorus-modified nickel-based catalyst Ni-P / HZSM-5, at a temperature of 270°C, a pressure of 3.5 MPa, a hydrogen circulation rate of 300 L / h, and a time of 45 min. After the treatment, the reaction products are subjected to multi-stage condensation at 20°C, 10°C, and -10°C to separate unreacted hydrogen and liquid crude fuel. The liquid crude fuel is then subjected to atmospheric distillation, and the components with a boiling range of 30–100°C are collected in stages to obtain crude biofuel.

[0074] The specific preparation steps of the phosphorus-modified nickel-based catalyst Ni-P / HZSM-5 are as follows:

[0075] S301: 10g of HZSM-5 molecular sieve was calcined at 550℃ for 5h, then mixed with 120mL of 1M ammonium nitrate solution, stirred at 80℃ for 3h, filtered, and the stirring treatment was repeated 3 times. After centrifugation and filtration, the mixture was washed until neutral and dried at 110℃ for 12h to obtain pretreated HZSM-5.

[0076] S302: 10g of pretreated HZSM-5 prepared in step S301 was immersed in 50mL of 0.3M nickel nitrate solution, stirred at 80℃ for 5h, centrifuged and filtered, dried at 110℃ for 12h, then heated to 500℃ in a tube furnace at a rate of 5℃ / min and calcined in air atmosphere for 4h, then switched to H2 at a flow rate of 50mL / min and reduced at 450℃ for 3h to obtain Ni / HZSM-5;

[0077] S303: Mix 10g of Ni / HZSM-5 prepared in step S302 with 5mL of 30wt% phosphoric acid solution, let stand at room temperature for 12h, dry at 110℃ for 12h, then heat to 550℃ in a muffle furnace at a rate of 2℃ / min, calcine in air atmosphere for 4h, and then hydrothermally age at 600℃ in 100% water vapor atmosphere for 8h to obtain Ni-P / HZSM-5;

[0078] S3: Nano-modification and fuel refining to obtain biomass fuel;

[0079] S401: Mix 0.25g of carbon nanotubes with 0.6g of sodium lignosulfonate in a certain proportion, add to 10mL of deionized water, and sonicate at 250W, 40kHz and 30min to obtain nano slurry.

[0080] S402: Mix 110 mL of crude biofuel prepared in step S402 and 1 mL of nano slurry prepared in step S401 in proportion, process at 9000 rpm for 20 min, and then homogenize at 45 MPa 3 times.

[0081] S403: After completing the homogenization process in step S402, hydrocarbon components with a boiling range of 30-80°C are collected in stages at a pressure of 12 kPa to obtain biomass fuel.

[0082] Comparative Example 1: The operation of Comparative Example 1 is basically the same as that of Example 1, except that maleic acid was not used for pretreatment in Comparative Example 1.

[0083] Comparative Example 2: The operation of Comparative Example 2 is basically the same as that of Example 1, except that the unmodified Ni / HZSM-5 catalyst is used instead of the phosphorus-modified nickel-based catalyst Ni-P / HZSM-5 in Comparative Example 2.

[0084] Comparative Example 3: The operation of Comparative Example 3 is basically the same as that of Example 1, except that the multi-stage condensation of 20°C, 10°C and -10°C in step S202 of Comparative Example 3 is changed to single-stage condensation of 0°C.

[0085] Comparative Example 4: The operation of Comparative Example 4 is basically the same as that of Example 1, except that carbon nanotubes are not added in step S401 of Comparative Example 4, and only sodium lignosulfonate is used.

[0086] Yield Test: The biofuel yields prepared by the processes in Examples 1-3 and Comparative Examples 1-4 were calculated. Biomass fuel yield (%) = final biomass fuel mass / raw material mass before pretreatment × 100%. The results are as follows: Figure 1 As shown.

[0087] Depend on Figure 1 The results show that the process of the present invention has excellent biomass fuel yield, especially the parameters of Example 1, which show the best process effect. The results of Comparative Example 1 show that the absence of maleic acid leads to insufficient decomposition of the amorphous region of cellulose, increased sugar degradation rate, increased lignin condensation by-products, increased mass loss in the pretreatment stage, and a simultaneous decrease in subsequent catalytic conversion rate, resulting in a significant decrease in yield. The results of Comparative Example 2 show that the deoxygenation efficiency of the unmodified catalyst is significantly reduced, and the increase in by-products leads to fuel mass loss and a significant decrease in yield. The results of Comparative Example 3 show that the absence of the multi-stage condensation process significantly reduces the recovery rate of C5-C12 light components, and the residue of high-boiling-point components leads to an increase in the cold filter plugging point of the fuel, resulting in significant mass loss of light fuel after distillation and a significant decrease in yield.

[0088] Performance testing: The yield of biofuel prepared by the processes of Example 1 and Comparative Examples 1-4 was tested. The kinematic viscosity was tested according to GB / T265-1988, the flash point of the biofuel was tested according to GB / T21789-2008, and the color was observed and recorded. The acid value of the biofuel was tested according to GB / T 7304-2020. The results are shown in Table 1 below.

[0089] Table 1. Biomass fuel performance test results

[0090]

[0091] As shown in Table 1, the biomass fuel prepared by the process of this invention has excellent chemical properties and is transparent and free of impurities.

[0092] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A process for producing biomass fuel using bio-cellulose, characterized in that, It includes the following steps: S1: Pretreatment of bio-fiber raw materials; S2: Biochemical conversion synergistically with catalytic conversion and deoxygenation to obtain crude biofuel; S3: Nano-modification and fuel refining to obtain biomass fuel; In step S1, the specific steps for the pretreatment of the bio-cellulose raw materials are as follows: S101: Dry the straw and then crush it to obtain biomass raw materials; treat the biomass raw materials under high temperature and high pressure, then add maleic acid and deionized water, and treat at high temperature to obtain hydrolysate; S102: Centrifuge the hydrolysate prepared in step S101, filter it, add activated carbon, adsorb it, filter it, and vacuum concentrate the sugar concentration to obtain pretreated bio-fiber. In step S2, the specific steps of the biochemical transformation synergistic catalytic transformation and deoxygenation are as follows: S201: The pretreated bio-fiber prepared in step S102 is mixed with continuously introduced hydrogen gas, preheated, and then a nickel-based catalyst Ni / Al2O3-SiO2 is added for primary catalytic deoxygenation. S202: After completing the catalytic deoxygenation operation in step S201, perform low-temperature alkylation treatment and high-temperature deoxygenation refining stage treatment; after the treatment is completed, the reaction products are separated into unreacted hydrogen and liquid crude fuel through multi-stage condensation, and the liquid crude fuel is distilled under normal pressure, and the components with boiling range of 30-100°C are collected in stages to obtain crude biofuel. In step S3, the specific steps of nano-modification and fuel refining are as follows: S401: Carbon nanotubes and sodium lignosulfonate are mixed in a certain proportion, added to deionized water, and ultrasonically treated to obtain nano slurry. S402: Mix the crude biofuel prepared in step S202 and the nano-slurry prepared in step S401 in a certain proportion, stir and shear, and then homogenize. S403: After completing the homogenization process in step S402, hydrocarbon components with a boiling range of 30-80°C are collected under pressure in stages to obtain biomass fuel. In step S401, the ratio of carbon nanotubes, sodium lignosulfonate, and deionized water is 2-3 g: 5-6 g: 100 mL; in step S402, the volume ratio of crude biofuel and nano-slurry is 100-120:

1.

2. The process for producing biomass fuel using bio-cellulose according to claim 1, characterized in that, In step S201, the parameters for the primary catalytic deoxygenation treatment include: a fixed-bed continuous reactor at 160–210°C, a pressure of 4 MPa, and a residence time of 30–60 min.

3. The process for producing biomass fuel using bio-cellulose according to claim 2, characterized in that, In step S202, the parameters for the low-temperature alkylation process include: substrate mass of 6% nickel-based catalyst Ni / HZSM-5, temperature of 210–230°C, pressure of 3.5–4 MPa, and residence time of 60–90 min.

4. The process for producing biomass fuel using bio-cellulose according to claim 3, characterized in that, In step S202, the parameters for the high-temperature deoxygenation and refining process include: substrate mass of 8% phosphorus-modified nickel-based catalyst Ni-P / HZSM-5, temperature of 250-270°C, pressure of 3.5 MPa, hydrogen circulation rate of 200-300 L / h, and time of 30-45 min.

5. The process for producing biomass fuel using bio-cellulose according to claim 4, characterized in that, Step S202, the specific preparation steps of the phosphorus-modified nickel-based catalyst Ni-P / HZSM-5 are as follows: S301: Calcine HZSM-5 molecular sieve, then mix it with ammonium nitrate solution, stir, filter, repeat stirring three times, centrifuge, filter, wash until neutral, and dry to obtain pretreated HZSM-5. S302: The pretreated HZSM-5 prepared in step S301 is immersed in nickel nitrate solution, stirred, centrifuged and filtered, dried, and then calcined at high temperature in air atmosphere. Then, H2 is introduced for reduction treatment to obtain Ni / HZSM-5. S303: The Ni / HZSM-5 prepared in step S302 is mixed with a phosphoric acid solution, allowed to stand at room temperature, dried, then calcined at high temperature in an air atmosphere, and subsequently hydrothermally aged in a water vapor atmosphere to obtain Ni-P / HZSM-5.

6. The process for producing biomass fuel using bio-cellulose according to claim 5, characterized in that, In step S301, the ratio of the amount of HZSM-5 molecular sieve to ammonium nitrate solution is 1g:10-12mL; in step S302, the ratio of the amount of pretreated HZSM-5 to nickel nitrate solution is 1g:5mL; in step S303, the ratio of the amount of Ni / HZSM-5 to 30wt% phosphoric acid solution is 1g:0.3-0.5mL.

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