Biofuel production method

Abstract

1. A method for producing biofuel using a lignin-rich feedstock comprising: providing a lignin-rich feedstock, the lignin-rich feedstock comprising greater than 60% by weight of lignin-based compounds obtained from delignification of biomass, the lignin-based compounds being selected from the group consisting of lignin-derived monomers, lignin-derived dimers, lignin-derived oligomers and combinations thereof; and performing a hydrodeoxygenation reaction on the lignin-rich feedstock, the hydrodeoxygenation reaction being carried out in a hydrogen-rich source at a temperature in the range of 300°C to 400°C, in the presence of a catalyst compatible with HDO reactions, under a H pressure in the range of 15 to 75 bar, more preferably 35 bar, for a period sufficient to result in a reformate having a total acid number (TAN) of about 10 to 35 mg KOH / g and a viscosity of 4 to 30 cP.

Description

[Technical field]

[0001] The present invention relates to a novel one-step process method for producing biofuels, and more specifically to a method for producing drop-in biofuels using hemicellulose and lignin rich streams. [Background technology]

[0002] In recent years, due to the depleting reserves and harmful environmental impacts of fossil fuels (e.g., natural gas, oil, and coal), clean and renewable energy sources are urgently needed to partially or completely replace fossil fuels (TJ Lindroos, E. Maki, K. Koponen, I. Hannula, J. Kiviluoma, and J. Raitila, “Replacing fossil fuels with bioenergy in district heating-Comparison of technology options,” Energy, vol. 231, 2021, doi:10.1016 / j.energy.2021.120799; and TEAmidon and S. Liu, “Water-based woody biorefinery,” Biotechnol.Adv.,vol.27,no.5,pp.542-550,2009,doi:10.1016 / j.biotechadv.2009.04.012.).

[0003] Biofuels derived from renewable sources have the inherent advantages of resource abundance and carbon neutrality. Fast pyrolysis (operating at >500 °C in an inert atmosphere) is the most common thermochemical process for biomass conversion and arguably the only industrially realized approach to convert dry biomass into liquid fuels (known as bio-oil or pyrolysis oil) with higher heating values ​​(HHV) of 15-20 MJ / kg [3]. On the other hand, hydrothermal liquefaction (HTL), operating at 200-400 °C under high pressure up to 20 MPa, is a more suitable and advantageous process for directly converting wet biomass (microalgae) or organic waste (food waste, wastewater sludge, etc.) into bio-crude oil (or HTL bio-oil) with an HHV of 25-30 MJ / kg [L. Plante et al., “Bioenergy from biofuel residues and waste,” Water Environ. Res., vol. 91, no. 10, pp. 1199-1204, 2019, doi: 10.1002 / wer.1214.].

[0004] Although the use of bio-oil provides environmental benefits by reducing CO2 emissions, the poor qualities of bio-oil, such as thermal instability, high viscosity and acidity, and low heating value, make it unsuitable for direct application as a drop-in fuel [VTTEnergy, “99 / 00150 Characterization of biomass-based flash pyrolysis oils,” Fuel Energy Abstr., vol. 40, no. 1, pp. 15-16, 1999, doi: 10.1016 / s0140-6701(99)92423-2; Z. Si, X. Zhang, C. Wang, L. Ma, and R. Dong, “An overview on catalytic hydrodeoxygenation of pyrolysis oil and its model compounds,” Catalysts, vol. 7, no. 6, pp. 1-22, 2017, doi: 10.3390 / catal7060169; and A. Pawar, NL Panwar, and BLSalvi,“Comprehensive review on pyrolytic oil production, upgrading and its utilization,” J.Mater.Cycles Waste Manag.,vol.22,no.6,pp.1712-1722,2020,doi:10.1007 / s10163-020-01063-w]. For example, the water content of pyrolytic bio-oil (15-30 wt%) is significantly higher than that of petroleum crude oil (<1 wt%). High water content in the oil can cause problems with engine ignition, not to mention significantly lower energy content [MHMarzbali et al.,“Wet organic waste treatment via hydrothermal processing: A critical review,” Chemosphere,vol.279,p.130557,2021,doi:10.1016 / j.chemosphere.2021.130557].Furthermore, the oxygen (O2) content in bio-oil from fast pyrolysis (35-50 wt%) is much higher than that of petroleum crude oil (<1 wt%). Such a high O2 content makes bio-oil soluble in polar solvents such as acetone and methanol, but almost incompatible with fossil fuels [S. Zhang et al., “Liquefaction of biomass and upgrading of bio-oil: A review,” Molecules, vol. 24, no. 12, pp. 1-30, 2019, doi: 10.3390 / molecules24122250]. Furthermore, the presence of high O2 content in bio-oil leads to low stability and strong acidity / corrosivity, thus having some adverse effects on oil storage and transportation, and causing some corrosion problems in downstream bio-oil upgrading / processing reactors [M. Zhang et al., “A review of bio-oil upgrading by catalytic hydrotreatment: Advances, challenges, and prospects,” Mol. Catal., vol. 504, no. September 2020, p. 111438, 2021, doi: 10.1016 / j.mcat.2021.111438].

[0005] Catalytic hydrodeoxygenation (HDO) is one of the most promising methods for upgrading bio-oil, which can efficiently reduce the oxygen content of pyrolysis bio-oil using high-pressure H2 while maintaining high oil yield [C. Guo, KT V Rao, Z. Yuan, S. (Quan) He, S. Rohani, and C. (Charles) Xu, “Hydrodeoxygenation of fast pyrolysis oil with novel activated carbon-supported NiP and CoP catalysts,” Chem. Eng. Sci., vol. 178, pp. 248-259, 2018, doi: 10.1016 / j.ces.2017.12.048]. However, this process usually operates under high pressure hydrogen gas, which increases safety concerns and process costs [W. Jin, L. Pastor-Perez, DK Shen, A. Sepulveda-Escribano, S. Gu, and T. Ramirez Reina, “Catalytic Upgrading of Biomass Model Compounds: Novel Approaches and Lessons Learnt from Traditional Hydrodeoxygenation-a Review,” ChemCatChem, vol. 11, no. 3, pp. 924-960, 2019, doi: 10.1002 / cctc.201801722].

[0006] In light of the state of the art, there remains a need for an approach that efficiently converts biomass into valuable bio-oil while overcoming one or many of the drawbacks known from the commonly applied methods, whether these drawbacks come from the feedstock or from the upgrading process of the oil obtained from the feedstock. Summary of the Invention

[0007] According to one aspect of the invention, a method for converting biomass to biofuel is provided.

[0008] The applicant's patent pending delignification process produces a bio-oil feedstock that is substantially free of cellulose derivatives, and thus its composition is enhanced compared to pyrolysis bio-oil. Pyrolysis of delignified biomass produces liquids (bio-oil) by pyrolyzing the liquid portion of the delignified biomass in the absence of air to apply high heat transfer rates to the biomass particles. The applicant's patent pending delignification process separates cellulose from other biomass components (lignin and hemicellulose) with +99% recovery and depolymerizes the lignin and hemicellulose into a liquid-rich organic liquid called lignin-hemicellulose-depolymerized-organic (LHDO). The applicant's LHDO is substantially free of aldehydes, and modifying the LHDO using hydrodeoxygenation (HDO) converts at least 70%, preferably at least 85%, and more preferably at least 95% of the carboxylic acids. This eliminates the role of bio-oil aldehydes in bio-oil stability from thermal application or stability over time. Aldehydes present in pyrolysis bio-oil react with sugars to form high molecular weight resins and oligomers through polymerization and condensation, and the oligomerization reactions result in highly undesirable coke formation in the bio-oil.Furthermore, Applicant's LHDO produces minimal and almost negligible char / coke during the HDO process, and the modified LHDO is fully miscible with jet, diesel, VGO and gasoline fuels without the need for a pretreatment step used in pyrolysis of bio-oil by oxidation followed by a mild temperature hydrotreating stage to eliminate the polymerization generated during the hydrocracking process.

[0009] It is noteworthy to point out that current pyrolysis of biomass generally results in large amounts of biochar (up to 30-40%). This is highly undesirable because the value of the biochar is low and the possibility of using the remaining bio-oil as a fuel additive, a high-value product, is greatly reduced by the large-volume conversion of biomass to biochar.

[0010] According to one aspect of the present invention, there is provided a method for producing biofuel using a hemicellulose and lignin rich feedstock, the method comprising: providing a lignin-rich feedstock, the lignin-rich feedstock comprising greater than 60% by weight of lignin-based compounds obtained from delignification of biomass, the lignin-based compounds being selected from the group consisting of lignin-derived monomers, lignin-derived dimers, lignin-derived oligomers and combinations thereof; - carrying out a hydrodeoxygenation reaction on the lignin-rich feedstock, the hydrodeoxygenation reaction being carried out in a hydrogen-rich source in the presence of a catalyst compatible with HDO reactions, at a temperature in the range of 250°C to 400°C, under a H2 pressure in the range of 15 to 75 bar, more preferably 35 bar, for a period sufficient to result in a reformate having a TAN of about 10 to 35 mg KOH / g and a viscosity of 4 to 30 cP; Includes.

[0011] Preferably, the lignin-rich feedstock comprises more than 80% by weight of lignin-based compounds obtained from the delignification of biomass, with the remainder of the feedstock being mainly composed of hemicellulose. More preferably, the lignin-rich feedstock comprises more than 85% by weight of lignin-based compounds obtained from the delignification of biomass, with the remainder of the feedstock being mainly composed of hemicellulose. Even more preferably, the lignin-rich feedstock comprises more than 90% by weight of lignin-based compounds obtained from the delignification of biomass. Even more preferably, the lignin-rich feedstock comprises more than 95% by weight of lignin-based compounds obtained from the delignification of biomass. According to a preferred embodiment of the method of the present invention, the lignin-rich feedstock comprises more than 97.5% by weight of lignin-based compounds obtained from the delignification of biomass. Preferably, the lignin-rich feedstock is essentially free of cellulose. According to one embodiment of the present invention, the lignin-rich feedstock contains a portion of the initial hemicellulose content of the biomass used. For example, in such cases, the lignin-rich feedstock contains about 15-20% of the initial hemicellulose content of the biomass used.

[0012] According to a preferred embodiment of the method of the present invention, the lignin-rich feedstock also contains dissolved hemicellulose resulting from a prior delignification reaction in which the lignin-rich feedstock was produced.

[0013] According to a preferred embodiment of the method of the present invention, the method further comprises a pretreatment step using an alkali salt to remove sulfuric acid present in the crude bio-oil.

[0014] According to a preferred embodiment of the method of the present invention, the alkali salt is a hydroxide salt selected from the group consisting of KOH; Ca(OH)2; NaOH, etc. Preferably, the alkali salt is Ca(OH)2. According to a preferred embodiment of the present invention, the catalyst is a Ru / C catalyst. Those skilled in the art will understand that catalysts commonly used in hydrodeoxygenation reactions can be used in the method according to the preferred embodiment of the present invention, and the interpretation of the catalyst should not be limited to those used in the accompanying examples.

[0015] According to a preferred embodiment of the method of the present invention, said period is about 2 hours.

[0016] According to a preferred embodiment of the method of the present invention, the temperature is about 350°C.

[0017] According to a preferred embodiment of the method of the present invention, the hydrogen-rich source is selected from the group consisting of alcohols, such as ethanol; gaseous hydrogen; and the like.

[0018] According to a preferred embodiment of the method of the present invention, the reformate has a charcoal content of less than 10% by weight. Preferably, the reformate has a charcoal content of less than 5% by weight. Preferably, the reformate has a charcoal content of less than 2% by weight. More preferably, the reformate has a charcoal content of less than 1% by weight.

[0019] According to a preferred embodiment of the method of the present invention, the process further comprises recovering the reformate.

[0020] According to another aspect of the present invention, there is provided a method for producing biofuel using a lignin-rich feedstock, the method comprising: providing a liquid lignin-rich LHDO feedstock obtained from a delignification process that separates cellulose from lignin and hemicellulose and depolymerizes the lignin and hemicellulose primarily into their monomers and dimers; - carrying out a hydrodeoxygenation reaction on the lignin-rich feedstock, the hydrodeoxygenation reaction being carried out in a hydrogen-rich source in the presence of a catalyst compatible with HDO reactions, at a temperature in the range of 300°C to 400°C, under a H2 pressure in the range of 15 to 75 bar, more preferably 35 bar, for a period sufficient to result in a reformate having a TAN of about 10 to 35 mg KOH / g and a viscosity of 4 to 30 cP; Includes.

[0021] Preferably, the LHDO is substantially free of aldehydes.

[0022] According to a preferred embodiment of the method of the present invention, when the LHDO is reformed in a hydrodeoxygenation (HDO) reaction, all the acids are converted. Preferably, the LHDO can also be reformed in a hydrodesulfurization (HDS) reaction. Preferably, the LHDO can also be reformed in a hydrodenitrogenation (HDN) reaction.

[0023] Features and advantages of the embodiments of the present application will become apparent from the following detailed description and the accompanying drawings. [Brief description of the drawings]

[0024] [Figure 1a] FIG. 1 shows a process flow diagram of a LHDO bio-oil reforming system according to a preferred embodiment of the present invention. [Figure 1b] FIG. 1 shows a process flow diagram of a LHDO bio-oil reforming system according to a preferred embodiment of the present invention. [Diagram 2] FTIR spectra of SWR crude oil and reformate at 350° C. [Diagram 3]FIG. 1 is a photograph of 2 wt. % reformate obtained according to a preferred embodiment of the present invention blended with 98 wt. % gasoline or virgin gas oil (VGO) - ((a) 300° C. reformate with gasoline; (b) 350° C. reformate with gasoline; (c) 300° C. reformate with VGO; (d) 350° C. reformate with VGO). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] The following description and the embodiments described therein are provided as illustrations of example(s) of specific embodiments of the principles of the present invention. These examples are provided for purposes of explanation, not limitation, of those principles and the invention.

[0026] According to one aspect of the present invention, a method for converting biomass to biofuel is provided. Preferably, the delignification is carried out at much milder conditions than the conventional Kraft process or other widely used delignification approaches. Also preferably, the result is a completely cellulose-free stream of lignin and hemicellulose depolymerized organic matter (LHDO).

[0027] One-step reaction for catalytic reforming of biomass-derived bio-oil into drop-in fuels In accordance with one aspect of the present invention, the process disclosed herein provides for the complete reforming and production of drop-in fuels from lignocellulosic biomass (e.g., found in wood, trees, straw, agricultural waste, and waste paper).

[0028] According to a preferred embodiment of the method of the present invention, the process utilizes a unique hemicellulose and lignin rich oil from crude bio-oil produced using the delignification process of the applicant's patent. The above-mentioned crude bio-oil is produced without the cellulosic portion of the biomass, improving its properties and allowing for easy upgrading more suitable for drop-in fuel. The hemicellulose and lignin rich oil stream refers to the oil resulting from the delignification of lignocellulosic biomass. According to a preferred method of the present invention, the hemicellulose and lignin rich oil is obtained as a by-product of delignification using milder conditions (temperature and pressure) than conventional chemical delignification as used during the Kraft process.

[0029] According to a preferred embodiment of the process of the present invention, biomass delignification was performed as follows: 3,368 g H2SO4 (93%), 3,746 g H2O2 (29%), 576 g H2O, and 310 g of modifier (e.g., taurine-related compound) were mixed in a 10:10:10:1 molar ratio in a 10 L glass reactor vessel. This modified acid / peroxide blend can be used to delignify lignocellulosic biomass to produce cellulose. When biomass (5% mass loading of wood shavings) is added to this blend at this scale, the reaction is highly exothermic and runs away. To prevent runaway reactions that result in cellulose decomposition and keep the mixture under control, small amounts of water (500 g each) are added to the reactor once the mixture reaches certain predefined temperatures: 35° C. (1st water addition); 37° C. (2nd water addition); 39° C. (1st water addition); and 41° C. (4th water addition, where the temperature rise in the reactor is small enough to keep the reaction going but not runaway). If there is too much water, the reaction will stop and the biomass will not be fully delignified. No external cooling was applied in any of the experiments. Thus, the delignification of the wood shavings was carried out at low temperature and atmospheric pressure. It is worth noting that in another preferred embodiment, external cooling can be applied.

[0030] The resulting streams of the above exemplary process include a cellulose stream containing solid cellulose fibers and a lignin-rich stream containing lignin removed from the biomass, as well as dissolved hemicellulose that is depolymerized during delignification and is present in the lignin-rich liquid phase.

[0031] According to a preferred embodiment of the method of the present invention, one of the advantages of this approach is that it focuses on the LHDO present in the lignin-rich stream compared to other approaches that use the whole biomass to produce biofuel. As a result, the portion of aromatic carbon (present in lignin and lignin monomers, dimers and oligomers resulting from delignification) is substantially higher than in processes that use the whole biomass (cellulose, lignin and hemicellulose). For example, in softwoods, the percentage of cellulose ranges from 40-50%, the percentage of lignin may range from 30-40%, and the remainder is hemicellulose. By removing the main component of lignocellulosic biomass (cellulose) from the process to produce biofuel, the aromatic carbon composition is increased and therefore the value of the biofuel is increased.

[0032] According to another aspect of the present invention, there is provided a process for carrying out controlled exothermic delignification of biomass, the process comprising: - providing a container; - providing a biomass comprising lignin, hemicellulose and cellulose fibers to said vessel; - providing an aqueous acidic composition comprising a sulfuric acid component; providing a peroxide component; - providing a modifier; - exposing the biomass to the sulfate source and the peroxide component to form a reaction mass; - contacting the sulfuric acid source and peroxide component with the biomass for a period of time sufficient for a delignification reaction to occur and remove greater than 97% by weight of the lignin and hemicellulose from the biomass; - the lignin and hemicellulose are recovered separately from the cellulose for further processing into bio-oil; Includes.

[0033] According to a preferred embodiment of the process of the present invention, the LHDO stream is subjected to a pH adjustment prior to undergoing reforming (ie, the HDO reaction).

[0034] According to preferred embodiments of the process of the present invention, the LHDO stream is substantially free of cellulose (i.e., less than 5 wt.% cellulose). More preferably, the LHDO stream contains less than 2 wt.% cellulose. Even more preferably, the LHDO stream contains less than 1 wt.% cellulose. Even more preferably, the LHDO stream contains less than 0.5 wt.% cellulose. Even more preferably, the LHDO stream contains less than 0.1 wt.% cellulose.

[0035] It is worth mentioning that almost all efforts to convert lignocellulosic biomass into fuels have failed due to undesirable interactions between the three main biomass components, and cellulosic ethanol represents a clear example of the above, besides the undesirable properties of pyrolysis bio-oil.

[0036] According to yet another aspect of the present invention, there is provided a process for delignifying biomass, the process comprising: - providing a container; - providing a biomass comprising lignin, hemicellulose and cellulose fibers to said vessel; - providing an aqueous acidic composition comprising a sulfuric acid component; providing a peroxide component; - exposing the biomass to the sulfate source and the peroxide component to form a reaction mass; - contacting the sulfuric acid source and peroxide component with the biomass for a period of time sufficient for a delignification reaction to occur and remove greater than 95% by weight of the lignin and hemicellulose from the biomass; - controlling the temperature of the delignification reaction by adding water to the vessel; Includes.

[0037] According to yet another aspect of the present invention, there is provided a process for delignifying biomass, the process comprising: - providing a container; - providing a biomass comprising lignin, hemicellulose and cellulose fibers to said vessel; - providing an aqueous acidic composition comprising a sulfuric acid component; providing a peroxide component; - exposing the biomass to the sulfate source and the peroxide component to form a reaction mass; - contacting the sulfuric acid source and peroxide component with the biomass for a period of time sufficient for a delignification reaction to occur and remove greater than 95% by weight of the lignin and hemicellulose from the biomass; - controlling the temperature of the delignification reaction by controlling the addition of biomass to the vessel; Includes.

[0038] According to a preferred embodiment of the present invention, a biomass containing lignin, hemicellulose and cellulose fibers is exposed to a modified Caro's acid composition selected from the group consisting of Composition A; Composition B and Composition C, The composition A is sulfuric acid in an amount ranging from 20 to 70% by weight of the total weight of the composition; - a compound comprising an amine moiety and a sulfonic acid moiety selected from the group consisting of taurine; taurine derivatives; and taurine-related compounds; and Peroxide Including, The composition B is Alkyl sulfonic acids; and Peroxide wherein the acid is present in an amount ranging from 40 to 80% by weight of the total weight of the composition, and the peroxide is present in an amount ranging from 10 to 40% by weight of the total weight of the composition; The composition C is -sulfuric acid; Compounds containing an amine moiety; Compounds containing a sulfonic acid moiety; and Peroxide Includes.

[0039] According to a preferred embodiment of the invention, biomass containing lignin, hemicellulose and cellulose fibers is exposed to the modified Caro's acid composition for a period of time sufficient for delignification to occur and remove greater than 95% by weight of the lignin and hemicellulose from the biomass. Preferably, a LHDO stream (containing lignin and hemicellulose but essentially no cellulose) is removed upon completion of the delignification for further processing into biofuel.

[0040] According to a preferred embodiment of the present invention, biomass containing lignin, hemicellulose and cellulose fibers is pretreated to remove most of the hemicellulose. Such treatment preferably results in a higher lignin fraction in the recovered liquid after delignification.

[0041] Preferably, the compound containing an amine moiety and a sulfonic acid moiety is selected from the group consisting of taurine; taurine derivatives; and taurine-related compounds.

[0042] Preferably, the taurine derivative or taurine-related compound is selected from the group consisting of sulfamic acid, taurolidine, taurocholic acid, tauroselecholic acid, tauromustine, 5-taurinomethyluridine and 5-taurinomethyl-2-thiouridine, homotaurine (tramiprosate), acamprosate, and taurate and aminoalkylsulfonic acid, where alkyl is selected from the group consisting of C1-C5 linear alkyl and C1-C5 branched alkyl. Preferably, the linear alkylaminosulfonic acid is selected from the group consisting of methyl, ethyl (taurine), propyl, and butyl. Preferably, the branched aminoalkylsulfonic acid is selected from the group consisting of isopropyl, isobutyl, and isopentyl.

[0043] According to a preferred embodiment of the invention, the compound comprising an amine moiety and a sulfonic acid moiety is taurine.

[0044] According to a preferred embodiment of the invention, the sulfuric acid and the compound containing an amine moiety and a sulfonic acid moiety are present in a molar ratio of 3:1 or greater.

[0045] According to a preferred embodiment of the present invention, the compound containing an amine moiety is an alkanolamine selected from the group consisting of monoethanolamine; diethanolamine; triethanolamine; and combinations thereof.

[0046] Preferably, the compound containing a sulfonic acid moiety is selected from the group consisting of alkylsulfonic acids; arylsulfonic acids; and combinations thereof. Preferably, the alkylsulfonic acid is selected from the group consisting of alkylsulfonic acids, the alkyl group of which ranges from C1 to C6 and which are linear or branched; and combinations thereof. More preferably, the alkylsulfonic acid is selected from the group consisting of methanesulfonic acid; ethanesulfonic acid; propanesulfonic acid; 2-propanesulfonic acid; isobutylsulfonic acid; t-butylsulfonic acid; butanesulfonic acid; isopentylsulfonic acid; t-pentylsulfonic acid; pentanesulfonic acid; t-butylhexanesulfonic acid; and combinations thereof. According to a preferred embodiment of the present invention, the arylsulfonic acid is selected from the group consisting of toluenesulfonic acid; benzenesulfonic acid; and combinations thereof.

[0047] According to a preferred embodiment of the present invention, the temperature of the reaction mass is maintained below 55° C. during the delignification reaction. Preferably, the temperature of the reaction mass is maintained below 50° C. during the delignification reaction. According to another preferred embodiment of the present invention, the temperature of the reaction mass is maintained below 45° C. during the delignification reaction. According to a preferred embodiment of the present invention, the temperature of the reaction mass is maintained below 40° C. during the delignification reaction.

[0048] According to a preferred embodiment of the present invention, the temperature of the reaction mass is controlled throughout the delignification reaction and subsequent addition of solvent (water) to gradually decrease the gradient of temperature increase per minute from less than 1° C. / min to less than 0.5° C. / min.

[0049] According to another preferred embodiment of the present invention, the temperature of the reaction mass is controlled by addition of a solvent (water) to reduce the temperature rise gradient per minute of the reaction mass to less than 1° C. / min.

[0050] According to yet another preferred embodiment of the present invention, the temperature of the mixture reaction mass is controlled by a second addition of solvent (water) to reduce the temperature rise gradient per minute of the reaction mass to less than 0.7°C / min.

[0051] Preferably, the temperature of the reaction mass is controlled by a third addition of solvent (water) to reduce the temperature ramp rate of the reaction mass to less than 0.3° C. / min.

[0052] Preferably, the temperature of the reaction mass is controlled by a fourth addition of solvent (water) to reduce the temperature ramp rate of the reaction mass to less than 0.1° C. / min.

[0053] According to a preferred embodiment of the present invention, the cellulose obtained has a Kappa number of less than 4.2.

[0054] According to a preferred embodiment of the present invention, -sulfuric acid; heterocyclic compounds; and -Peroxide A process for delignifying biomass using an aqueous acidic composition comprising:

[0055] According to another preferred embodiment of the present invention, -sulfuric acid; -Heterocyclic compounds A process for delignifying biomass using an aqueous acidic composition comprising: Here, the sulfuric acid and the heterocyclic compound are present in a molar ratio of 1:1 or greater.

[0056] Preferably, the sulfuric acid and the heterocyclic compound are present in a molar ratio ranging from 28:1 to 2:1. More preferably, the sulfuric acid and the heterocyclic compound are present in a molar ratio ranging from 24:1 to 3:1. Preferably, the sulfuric acid and the heterocyclic compound are present in a molar ratio ranging from 20:1 to 4:1. More preferably, the sulfuric acid and the heterocyclic compound are present in a molar ratio ranging from 16:1 to 5:1. According to a preferred embodiment of the present invention, the sulfuric acid and the heterocyclic compound are present in a molar ratio ranging from 12:1 to 6:1.

[0057] Also preferably, the heterocyclic compound has a molecular weight of less than 300 g / mol. Also preferably, the heterocyclic compound has a molecular weight of less than 150 g / mol. More preferably, the heterocyclic compound is a secondary amine. According to a preferred embodiment of the present invention, the heterocyclic compound is selected from the group consisting of imidazole; triazole; and N-methylimidazole.

[0058] According to one aspect of the present invention, -sulfuric acid; Heterocyclic compounds; and Peroxide A process for delignifying biomass, such as wood, using an aqueous acidic composition comprising: Here, the sulfuric acid and the heterocyclic compound are present in a molar ratio ranging from 2:1 to 28:1.

[0059] method Bio-oil HDO reforming experiments were carried out in a 500 mL stainless steel Parr autoclave reactor (Illinois, USA) equipped with a magnetic stirrer, pressure gauge and thermocouple. Bio-oil was reformed by HDO in supercritical ethanol (critical point 241 °C and 63 bar).

[0060] Supercritical ethanol is an effective hydrogen donor solvent to avoid the risk of utilizing pure hydrogen in small-scale experiments during catalytic reforming processes. It can act as an in-situ hydrogen donor and react with bio-crude oil to generate hydroxyl and hydrogen radicals [

[12] J.-H. Lee, I.-G. Lee, J.-Y. Park, and K.-Y. Lee, “Efficient upgrading of pyrolysis bio-oil over Ni-based catalysts in supercritical ethanol,” Fuel, vol. 241, pp. 207-217, 2019, doi:10.1016 / j.fuel.2018.12.025; and R. Jogi et al., “Biocrude production through hydro-liquefaction of wood biomass in supercritical ethanol using iron silica and iron beta zeolite catalysts,” J.Chem.Technol.Biotechnol.,vol.94,no.11,pp.3736-3744,2019,doi:10.1002 / jctb.6181].

[0061] FIG. 1 shows a process flow diagram of a LHDO bio-oil reforming system. The following numbers identify the components of a delignification plant and bio-oil reformer according to a preferred embodiment of the present invention. The process begins with delignification of lignocellulosic biomass by a patent pending delignification process (101), the LHDO is stored in a feed tank (102), and a feed pump (103) pumps the LHDO to a furnace (104) where it is heated to a target temperature and then fed to a reactor (105) for hydrodeoxygenation reaction. In some embodiments, the reactor performs a hydrodesulfurization (HDS) reaction. In some embodiments, the reactor performs a hydrodenitrogenation (HDN) reaction. The reformed biofuel is then sent to a heat exchanger (106), an air cooler (107) before filtration, gas / liquid separation in a filtration unit (108) and a gas / liquid separator (109). The gas compressor (110) collects the gaseous portion and sends it to a hydrogen membrane separator (113) where the hydrogen is recovered and returned to the hydrogen storage tank (112), and the remaining hydrocarbon gas is sent to the fuel gas system (114). From the filter, the recovered liquid portion can be sent to a drop-in fuel tank (111).

[0062] FIG. 1b shows a process flow diagram of the LHDO bio-oil reforming system. The following numbers identify the components of the delignification plant and bio-oil reformer according to a preferred embodiment of the present invention. The process begins with delignification of lignocellulosic biomass by a patent pending delignification process (201), the LHDO is stored in a feed tank (202), and a feed pump (203) pumps the LHDO to a furnace (204) where it is heated to a target temperature and then fed to a reactor (205) for hydrodeoxygenation reaction. The reformed biofuel is then sent to a heat exchanger (206), an air cooler (207) before filtration, gas / liquid separation in a filtration unit (208) and a gas / liquid separator (209). The gas compressor (210) collects the gaseous portion and sends it to a hydrogen membrane separator (213) where the hydrogen is recovered and returned to the hydrogen storage tank (212) and the remaining hydrocarbon gas is sent to the fuel gas system (214). From the filter, the recovered liquid portion can be sent to the drop-in fuel tank (211). This liquid can be further sent to a distillation column (215) where the LHDO is split into various hydrocarbons such as sustainable aviation fuel, biodiesel, etc. and then sent to a hydrocarbon storage tank (216).

[0063] According to a preferred embodiment of the present invention, a pretreatment procedure using Ca(OH)2 was developed to remove sulfuric acid in the feed crude bio-oil to obtain sulfur-water-removed (SWR) crude bio-oil for upgrading.

[0064] According to a preferred embodiment of the present invention, a 500 mL Parr autoclave reactor was charged with 70 g of pretreated bio-oil and 70 g of ethanol-water mixed solvent (1:1 w / w), and Ru / C catalyst (10 wt. % bio-oil on a dry basis). The reactor was sealed and leak tested with compressed nitrogen, and then the residual air in the reactor was removed by purging and evacuating with pressurized nitrogen three times. The reactor was then pressurized to 35 bar with pure hydrogen and heated to 300° C. and 350° C. under constant stirring (approximately 300 rpm) and held at this temperature for 2 hours.

[0065] At the end of each run, the reactor was quenched in a water bath. After cooling the reactor to ambient temperature (about 25° C.), the gaseous products were collected in a gas bag and analyzed using GC-TCD to determine the composition and yield of the gaseous products. The reactor was then opened and the reaction mixture was transferred to a 500 mL beaker. The reactor and agitator were washed with dichloromethane three times and the resulting washings were combined with the reaction mixture. The mixture of the reaction contents and washings was then filtered under vacuum. The solid product retained on the filter paper (VWR® Grade 413 filter paper) was oven-dried at 105° C. for 12 hours to recover the solid residue (spent catalyst with carbon / coke deposits), while the filtrate was extracted with dichloromethane to remove water and then evaporated under reduced pressure to remove the solvent to recover the reformate for further analysis (CHNS elemental composition, GC-MS, FTIR, etc.). According to a preferred embodiment of the present invention, different commercially available refinery catalysts and hydrogenation catalysts can be considered within the scope of the present invention. Preferably, the catalyst is selected from the group consisting of ruthenium on activated carbon (Ru / C), ruthenium on activated carbon with ferrous oxide (Ru / C-Fe2O3), nickel-molybdenum (NiMo), cobalt-molybdenum (CoMo), and platinum and palladium on zeolites Y and HZSM-5. According to a preferred embodiment of the present invention, a combination of the above catalysts is used.

[0066] Total Acid Number (TAN) is an important quality test for crude oil refining. It provides an indication of weak organic and strong inorganic acids present in the oil and is essential to prevent damage and maintain and protect equipment. The desired TAN range of the drop-in fuel is within the same range of the crude oil it is blended with, ensuring that the overall TAN of the blended drop-in fuel meets the corresponding specification ASTM D8045 for that fuel.

[0067] Viscosity plays a very important role in the fuel system, affecting the fuel's ability to lubricate fuel system components, and atomization. Poor fuel atomization leads to poor combustion, which leads to multiple issues such as power loss and fuel economy. The target viscosity range is usually dependent on the drop-in fuel target. In other words, after the drop-in blend is completed, the viscosity range shall be within the ASTM range to ensure compliance with the above-mentioned criteria. This is also governed by the percentage of the drop-in fuel value, which is usually reflected in the measured final viscosity number of the blended fuel.

[0068] The product yields (upgraded bio-oil, carbon / coke, gas products) were calculated by the weight % of the products relative to the dry mass of the LHDO crude bio-oil feedstock.

[0069] As shown in Table 1, compared to LHDO crude bio-oil, the reformate according to the preferred embodiment of the present invention has much lower TAN and viscosity values, especially for the 350°C reformate, which has a lower TAN and viscosity of 2.5 mg KOH / g and 3.4 cP, respectively. Reforming at 350°C increased the reformate yield by 17%, from (18.1%) at 300°C to (21.2%).

[0070] GC-MS (Agilent Technologies, 5977A MSD with HP-5MS column) was used to analyze the chemical composition of the volatile fractions of LHO crude bio-oil and reformate at 300 °C and 350 °C, and the results after the reforming process are listed in Table 2. As clearly shown, all the acids initially present in the LHDO crude bio-oil were removed and disappeared. This supports the hypothesis that these acids were converted to esters. HDO reforming also significantly increased the concentration of hydrocarbons and aromatics in the reformate. [Table 1]

[0071] Furthermore, the presence of high oxygen content in bio-oil leads to low stability and strong acidity / corrosivity, thus having some adverse effects on the storage and transportation of the oil, and creates some corrosion issues in downstream reforming / processing reactors of bio-oil. This is compared to fast pyrolysis bio-oil, which is a darker viscous liquid due to the higher presence of water and numerous chemical compounds in various reactive functional groups such as carbonyl compounds, making the bio-oil highly oxygenated and acidic (pH 2.5), subject to phase separation and polymerization over time or upon heating. Furthermore, the oxygen (O) content in bio-oil from fast pyrolysis (35-50 wt%) is much higher than that of petroleum crude oil (<1 wt%). Such high oxygen content makes bio-oil soluble in polar solvents such as acetone and methanol, but barely miscible with fossil fuels.

[0072] Hydrodeoxygenation tests were carried out on lignin-rich oil LHDO using a set of commercial catalysts at 300°C and 350°C, 35 bar H2 pressure, and 2 h reaction time to obtain reformate that is clear and miscible with hydrocarbon fuels such as diesel, jet fuel, and vacuum gas oil (VGO). The reformate has much lower total acid number (TAN) and viscosity values, especially for reformate with TAN of about 10-35 mg KOH / g and viscosity of 4-30 cP at 350°C.

[0073] After the reforming process, all the acids in the crude bio-oil disappeared. It is assumed that the acids were converted to esters. Hydrodeoxygenation (HDO) reforming also significantly increased the concentration of hydrocarbons and aromatics in the reformate. Tables 1 and 2 show comparable results for the raw and reformed bio-oils. [Table 2]

[0074] Referring to FIG. 2, FTIR spectra of the SWR crude oil and reformate at 350°C were also carried out. After the reforming process, the peaks at 2970–2860 cm -1 and 1460~1370cm -1New IR absorption peaks appear between 1600 cm and 1700 cm. These peaks can be ascribed as CH stretching and CH bending, respectively, and are hypothesized to suggest the formation of alkanes in HDO, as evidenced by the GC-MS results. Furthermore, new IR absorption peaks appear between 1600 cm and 1700 cm, as confirmed by the GC-MS results. -1 C=C stretching at 730cm -1 The C=C bend at 3300 cm indicated the presence of aromatics in the reformate (Table 2). -1 (OH extension), 1147cm -1 (CO stretching), and 1025 cm -1 The IR peaks of (S=O stretching) almost completely disappeared in the reformate, suggesting effective hydro-deoxygenation (HDO) and hydro-desulfurization (HDS) during HDO reforming. The above is in very good agreement with the chemical analysis results obtained by elemental analysis.

[0075] According to a preferred embodiment of the present invention, HDO reforming of the feedstock under 35 bar hydrogen gas in an ethanol-water mixed solvent (50 / 50, by weight) at 300°C and 350°C for 2 h produced reformate with yields of 18.1 wt% and 21.2 wt%, respectively.

[0076] According to a preferred embodiment of the present invention, the upgraded bio-oil has much lower TAN and viscosity values, as well as increased concentrations of esters, hydrocarbons and phenols, and is free of carboxylic acids, as compared to the raw bio-oil.

[0077] Elemental, GC-MS and FTIR characterization of the upgraded bio-oil suggest effective hydrodeoxygenation (HDO) and hydrodesulfurization (HDS) during HDO upgrading.

[0078] According to a preferred embodiment of the present invention, the bio-oil reformed at 350°C has much better quality than the reformate obtained at 300°C, i.e., much lower TAN (2.5 mg KOH / g), lower viscosity (3.4 cP at 50°C), and complete solubility in gasoline and VGO.

[0079] In one experiment, a total of 105 grams of reformate was obtained from the 350°C feed crude oil by HDO.

[0080] 3 is a photograph of 2 wt. % reformate obtained according to a preferred embodiment of the present invention mixed with 98 wt. % gasoline or VGO after 30 min of ultrasonic agitation and 2 h standing. ((a) 300° C. reformate with gasoline; (b) 350° C. reformate with gasoline; (c) 300° C. reformate with VGO; (d) 350° C. reformate with VGO).

[0081] According to a preferred embodiment of the present invention, the produced reformed bio-oil was utilized as a drop-in fuel with hydrocarbon fuels, i.e. diesel fuel, jet fuel, and then subjected to the above-mentioned ASTM standard tests for hydrocarbon fuels. The third-party ASTM test results confirmed the suitability of the reformed bio-oil as a drop-in fuel, and it met all the ASTM tests performed by the accredited third-party organization.

[0082] Although the foregoing invention has been described in some detail for purposes of clarity and understanding, those skilled in the art will appreciate upon familiarity with the disclosure that various changes in form and detail can be made therein without departing from the true scope of the invention as set forth in the appended claims.

Claims

1. A method for producing biofuel using lignin-rich raw materials, wherein the method is - To provide a lignin-rich raw material, wherein the lignin-rich raw material contains more than 60% by weight of a lignin-based compound obtained from deligninization of biomass, and the lignin-based compound is selected from the group consisting of lignin-derived monomers, lignin-derived dimers, lignin-derived oligomers, and combinations thereof. - A hydrogenation deoxygenation reaction is carried out on the lignin-rich raw material, wherein the hydrogenation deoxygenation reaction is carried out in the presence of a catalyst suitable for the HDO reaction for a period of time sufficient to produce a reformed oil having a total acid number (TAN) of about 10 to 35 mg KOH / g and a viscosity of 4 to 30 cP, and at a temperature of 15 to 75 bar, more preferably 35 bar. ２ The process is carried out under pressure, at temperatures in the range of 250°C to 400°C, in a hydrogen-rich source. Methods that include...

2. The method according to claim 1, wherein the raw material contains more than 80% by weight of a lignin-based compound obtained from deligninization of biomass.

3. The method according to claim 1, wherein the raw material contains a lignin-based compound obtained from deligninization of biomass in an amount of more than 85% by weight.

4. The method according to claim 1, wherein the raw material contains more than 90% by weight of a lignin-based compound obtained from deligninization of biomass.

5. The method according to claim 1, wherein the raw material contains more than 95% by weight of a lignin-based compound obtained from deligninization of biomass.

6. The method according to claim 1, wherein the raw material contains more than 97.5% by weight of a lignin-based compound obtained from deligninization of biomass.

7. The method according to claim 1, wherein the raw materials also include dissolved hemicellulose produced from a prior delignin reaction that generated the lignin-rich raw materials.

8. The method according to claim 1, further comprising a pretreatment step of using an alkali salt to remove sulfuric acid present in the crude bio-oil.

9. The alkali salts mentioned above are KOH; Ca(OH) ２ The method according to claim 8, wherein the hydroxide salt is selected from the group consisting of NaOH, etc.

10. The alkali salt is Ca(OH) ２ The method according to claim 9.

11. The method according to claim 1, wherein the aforementioned period is approximately 2 hours.

12. The method according to claim 1, wherein the temperature is approximately 350°C.

13. The method according to claim 1, wherein the hydrogen-rich source is selected from the group consisting of alcohols, such as ethanol; gaseous hydrogen, etc.

14. The method according to claim 1, wherein the modified oil has a charcoal content of less than 10% by weight, more preferably less than 5% by weight.

15. The method according to claim 1, wherein the modified oil has a charcoal content of less than 2% by weight.

16. The method according to claim 1, wherein the modified oil has a charcoal content of less than 1% by weight.

17. The method according to claim 1, further comprising the step of recovering the modified oil.

18. A method for producing biofuel using lignin-rich raw materials, wherein the method is - To provide a liquid lignin-rich LHDO raw material obtained from a deligninization process that separates cellulose from lignin and hemicellulose and depolymerizes lignin and hemicellulose mainly into their monomers and dimers, - A hydrogenation deoxygenation reaction is carried out on the lignin-rich raw material, wherein the hydrogenation deoxygenation reaction is carried out in the presence of a catalyst suitable for the HDO reaction for a period of time sufficient to yield a reformed oil having about 10 to 35 mg KOH / g of TAN and a viscosity of 4 to 30 cP, and at a pressure of 15 to 75 bar, more preferably 35 bar of H ２ The process is carried out under pressure, at temperatures in the range of 250°C to 400°C, in a hydrogen-rich source. Methods that include...

19. The method according to claim 1, wherein the LHDO contains up to 2% of an aldehyde-containing compound.

20. The method according to claim 1, wherein when LHDO is modified in the hydrogenation deoxygenation (HDO) reaction, substantially all carboxylic acids are converted.

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