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Pyrolysis of lignocellulosic materials typically form carbonaceous residues (chars) with structures similar to the starting material. However, previous studies reported in the literature have shown that fast pyrolysis of cellulose and lignin form a molten intermediate liquid resulting in chars with smooth surfaces and evidences of intense bubbling. The fraction responsible for morphology conservation during pyrolysis is not known. In this article, pyrolysis visualization studies were carried out with a fast camera on cellulose, xylan, Organosolv lignin (OL), milled wood lignin (MWL), and lignocellulosic sugarcane bagasse to identify the component responsible for morphological conservation. The materials were heated using a modified Pyroprobe with measured sample heating rates close to 100 °C/s. Our studies confirm that cellulose, lignin, and deashed xylan are completely transformed into an intermediate liquid; the intensity of bubbling for lignin was far superior that of cellulose. Xylan as received, however, only forms a small amount of intermediate liquid; it does not fully melt and maintains its general shape during pyrolysis. These results suggest that the presence of mineral matter is critical for lignocellulosic materials to retain their original morphology. We repeated the studies on raw bagasse and acid washed bagasse. The raw bagasse retains its morphology; the acid washed bagasse shrank dramatically, but was not completely converted into a liquid. Our results suggest that in addition to hemicellulose with the presence of ash, other biomass fractions or the different temperatures at which the different fractions melt and solidify could also be contributing to maintain the structure of the lignocellulosic material during pyrolysis. [ABSTRACT FROM AUTHOR]

This paper reports studies on the film pyrolysis of sugarcane bagasse in an electrically heated hot plate reactor. The new experimental set up used is described. The bagasse studied was ground to particle sizes less than 37 μm (mesh 400) and was mixed with water to form the paste to be used to form the biomass film (10 mg of sugarcane bagasse distributed evenly on a steel plate, 60 μm thick). All the tests were conducted under vacuum (150 mbar). The effect of heating rate (between 5 and 1200 °C/s) and final temperatures (between 250 and 650 °C) on product yields (permanent gases, water, light volatile, pyrolytic lignin, sugars and char) were studied. The yield of fragmentation and dehydration products increased as heating rates augment. The effect of heating rate is only important till 100 °C/s, no significant changes in product yields are observed at higher heating rates. Bio-oils enriched in lignin and sugars oligomers were obtained at high temperatures and heating rates. These results suggest that good yields of fermentable sugars may be obtained in pyrolysis reactors working at intermediary pyrolysis conditions. [ABSTRACT FROM AUTHOR]

The aim of this work was to improve sugarcane bagasse thermochemical conversion to pyrolytic sugars production, particularly to levoglucosan. The experiments were carried out evaluating the effect of acid washing with HNO 3 (0.1 wt.%) followed by H 2 SO 4 addition (0.1, 0.2 and 0.3 wt.%) at pyrolysis temperatures of 350, 400, 450, 500, 550 and 600 °C was studied by Py-GC/MS. The experimental results showed that HNO 3 washing, followed by H 2 SO 4 concentration of 0.2 wt.% at 350 °C resulted in an increase in levoglucosan yield between 5 and 7 times the yield obtained when the raw bagasse was processed. Thus, these results are very attractive to improve pyrolytic sugars production in sugarcane bagasse by previously acid treatment to pyrolysis technology. [ABSTRACT FROM AUTHOR]

Six alternatives for the conversion of an average Colombian palm oil mill (30 t h −1 of fresh fruit bunches (FFB) into biorefineries were evaluated. The alternatives studied were: (C1) Production of biogas from the Palm Oil Mill Effluents (POME), (C2) Composting of empty fruit bunches (EFB) and fiber, (C3) Biomass combustion for high pressure steam combined heat and power, (C4) Pellets production, (C5) Biochar production and, (C6) Biochar and bio-oil production. The available biomass could result in up to 125 kWh of electricity, 207 kg of compost, 125 kg of pellet, 44 kg of biochar and 63 kg of bio-oil per metric ton of FFB. The global warming potential (GWP), eutrophication potential (EP), net energy ratio (NER), capital expenditures (CAPEX), operational costs (OPEX), net present value (NPV) and internal rate of return (IRR) were calculated for all the alternatives. GHG reductions of more than 33% could be achieved. Anaerobic digestion and composting contributed to 30% reduction of the EP. The CAPEX for all of the biorefinery alternatives studied varies between 0.7 $ t −1 and 2.8 $ t −1 of FFB. The OPEX varies between 1.6 $ t −1 and 7.3 $ t −1 of FFB. The NPV for viable scenarios ranged between 2.5 million and 13.9 million US dollars. The IRR calculated varied between 3% and 56% and the payback periods were between 3 and 8 years. The total extra incomes reached values up to 15.2 $ t −1 of FFB. Overall the pellets production biorefinery was the preferred alternative. [ABSTRACT FROM AUTHOR]

A new methodology has been proposed to describe of the dynamics of bubble formation during pyrolysis of Organosolv lignin and sucrose (surrogates for biomass) using fast speed visualization (125fps) with mathematical modeling. The model uses a population balance to predict overall rates of bubble birth and death, bubble bursting, and aerosol ejection. The experimental studies were performed on a uniquely modified CDS Analytical Pyroprobe 5000 to visualize the formation of bubbles within the liquid intermediate phase at heating rates close 100 °C/s. Experimentally, we observed that bubbles follow a log-normal distribution versus bubble size within the liquid intermediate phase for both materials. This distribution function changes over time due to increased viscosity from solidification reactions that generate char and the changes in the rate of bubble formation. Micro-explosion intensity was used to estimate aerosol ejection intensity. The model predicts aerosol ejection yields of 21.18% w/w from Organosolv lignin and 17.40% w/w from sucrose during pyrolysis with an average droplet size of 10 μm. [ABSTRACT FROM AUTHOR]

Oleaginous strains of Rhodococcus including R. jostii RHA1 have attracted considerable attention due to their ability to accumulate triacylglycerols (TAGs), robust growth properties and genetic tractability. In this study, a novel metabolic pathway was introduced into R. jostii by heterogenous expression of the well-characterized gene, lgk encoding levoglucosan kinase from Lipomyces starkeyi YZ-215. This enables the recombinant R. jostii RHA1 to produce TAGs from the anhydrous sugar, levoglucosan, which can be generated efficiently as the major molecule from the pyrolysis of cellulose. The recombinant R. jostii RHA1 could grow on levoglucosan as the sole carbon source, and the consumption rate of levoglucosan was determined. Furthermore, expression of one more copy of lgk increased the enzymatic activity of LGK in the recombinant. However, the growth performance of the recombinant bearing two copies of lgk on levoglucosan was not improved. Although expression of lgk in the recombinants was not repressed by the glucose present in the media, glucose in the sugar mixture still affected consumption of levoglucosan. Under nitrogen limiting conditions, lipid produced from levoglucosan by the recombinant bearing lgk was up to 43.54 % of the cell dry weight, which was comparable to the content of lipid accumulated from glucose. This work demonstrated the technical feasibility of producing lipid from levoglucosan, an anhydrosugar derived from the pyrolysis of lignocellulosic materials, by the genetically modified rhodococci strains. [ABSTRACT FROM AUTHOR]

Two-step hydrotreatment experiments were performed using three completely different bio-oil fractions namely: whole bio-oil, heavy bio-oil obtained after fractional condensation of pyrolysis vapours and pyrolytic lignin obtained by cold water precipitation of the bio-oil. The aim is to study the de-oxygenation and in addition SEC and UV-fluorescence analysis was used to identify the importance of cracking, polymerization and hydrogenation reactions of the three different bio-oil feedstocks. In the first step hydrotreatment, Ru/C was used at 250 or 300 °C with reaction time of 2 h. In the second step hydrotreatment, Ni-Mo/Al 2 O 3 catalyst was used at 375 or 400 °C, with reaction time of 2 or 4 h. During stabilization in the first step, pyrolytic lignin was hydrogenated to a large extent accompanied by cracking reactions. In the second step, unsulphided Ni-Mo/Al 2 O 3 catalyst was active enough to effectively crack pyrolytic lignin into smaller molecules. High molecular weight compounds including large aromatic ring structures were formed from the reactive sugar rich fraction in both first step stabilization and second step hydrotreatment. The newly formed polymerization products were difficult to crack even at extended reaction times of 4 h at 400 °C. Importantly, the presence of water (and light oxygenates) could significantly supress the polymerization reactions. [ABSTRACT FROM AUTHOR]

This paper reports the effects of pyrolysis temperature on biochar to oxidation by air. Eighteen biochars were produced from the pyrolysis of Douglas fir wood (DFW), Douglas fir bark (DFB), and hybrid poplar wood (HP) at six temperatures (623, 673, 723, 773, 823 and 873 K) in a lab scale spoon reactor. The oxidation step for all biochars produced was conducted at 523 K in the presence of air in a spoon reactor. The elemental and proximate analyses of all the oxidized and un-oxidized chars suggest that the carbonaceous materials produced at low temperature are more susceptible to oxidation than those produced at high temperature. A number of surface properties of resultant biochars were examined to better understand how pyrolysis temperatures and feedstock sources relate to the development of surface characteristics. The removal of volatiles during the pyrolysis step resulted in the gradual creation of microporosity detectable by CO 2 adsorption but which was difficult to detect with N 2 adsorption, suggesting that the chars contain micropores mostly less than 1 nm in entrance dimension. In some cases, the surface area decreased after being oxidized likely due to the blockage of micropores by oxygen-containing functional groups. The surface composition determined by XPS and Boehm titration confirms that greater quantities of carbonyl and carboxyl groups are formed on biochars produced at low temperature. The formation of these oxygenated functional groups contributes to add negative charges on the surface and consequently the pH at the point of zero charge increases for un-oxidized biochars. [ABSTRACT FROM AUTHOR]

Wheat straw is a potential feedstock in biorefinery for sugar production. However, the cellulose, which is the major source of sugar, is protected by lignin. Ozonolysis deconstructs the lignin and makes cellulose accessible to enzymatic digestion. In this study, the change in lignin concentration with different ozonolysis times (0, 1, 2, 3, 5, 7, 10, 15, 20, 30, 60 min) was fit to two different kinetic models: one using the model developed by Garcia-Cubero et al. (2012) and another including an outer mass transfer barrier or “cuticle” region where ozone mass transport is reduced in proportion to the mass of unreacted insoluble lignin in the cuticle. The kinetic parameters of two mathematical models for predicting the soluble and insoluble lignin at different pretreatment time were determined. The results showed that parameters derived from the cuticle-based model provided a better fit to experimental results compared to a model without a cuticle layer. [ABSTRACT FROM AUTHOR]

The use of ozone to increase the cation exchange capacity (CEC) of two chars produced from pyrolysis of Douglas fir ( Pseudotsuga menziessii ) and a control bituminous coal activated carbon (AC) is reported. Chars were produced from the wood fraction of Douglas fir (DFWC) and the bark (DFBC) at 500 °C using an auger driven reactor with a nitrogen sweep gas under mild vacuum. Five ozone treatment times, ranging from 5 min to 60 min, were investigated. The initial properties of each char were found to differ significantly from the other samples in terms of surface area, proximate composition, and elemental composition. DFWC did not show significant mass loss or temperature variation during ozone treatment; however, after 1 h of oxidation both DFBC and AC samples resulted in 20% and 30% mass loss, respectively, and reactor temperatures in excess of 60 °C. Analysis of the pore size distribution of each treatment shows that ozone treatment did not significantly affect small micropores after 30 min of treatment for any material, but did reduce the apparent surface area of mesopores. Increases in carboxylic groups were identified with ozone treatment and found to correlate strongly with changes in measured CEC. The formation of lactone was found to correlate positively with reactor temperature during oxidation. These results indicate that the properties of chars, including surface area, pore structure, and chemical composition, as well as reactor conditions strongly affect the ozone oxidation of chars. [ABSTRACT FROM AUTHOR]

• Twenty biorefinery concepts for the production of Sustainable Aviation Fuels (SAFs) in a 12,444 MT sugarcane mill were studied. • Five SAF technologies were analyzed. • Fourteen out of fifteen scenarios resulted in capital reductions (5 to 86%). • We identified MFSPs reductions between 8 and 53%. • Twelve scenarios yielded GHG savings from 10 to 100%. A large sugarcane mill with a processing capacity of 12,444 metric ton sugarcane per day is used as a host plant for the evaluation of several bio-refinery concepts to produce sustainable aviation fuels (SAF). Five SAF technologies are studied: Virent's BioForming, alcohol to jet, direct sugar to hydrocarbon, fast pyrolysis-bio-oil hydrotreatment, and gasification & Fischer-Tropsch technologies. A standardized methodology is followed to evaluate twenty integrated scenarios to produce fuels using sugarcane mill facilities. In our analyses we assumed that the sugarcane mill operates 6 months but that the SAF unit operates twelve months (with switchgrass, molasses, and ethanol purchases). For each of the scenarios, the minimum fuel selling price (MFSP) and greenhouse gas emissions (GHG) within the integrated scenarios are estimated. Fourteen out of fifteen integrated scenarios resulted in reductions of capital (5 to 86 %) and operational costs (4 to 34 %) compared with the base case processes. These benefits are associated with a better use of sugarcane mill's infrastructure, co-products availability (molasses and ethanol) as well as waste stream feedstocks (surplus bagasse). It was possible to identify conditions reducing MFSPs between 8 and 53 % from corresponding base cases. Twelve scenarios yielded GHG savings from 10% to 97%. [ABSTRACT FROM AUTHOR]

Polyhydroxyalkanoate (PHA) production generates a significant amount of residual bacterial biomass (RBB) after PHA extraction. The RBB as a zero-value waste contains proteins, carbohydrates, phenolics, and ash, which can be managed and converted to bio-oil and biochar products by pyrolysis. Thermogravimetric analysis (TGA) was used to investigate the thermodegradation kinetics of RBB and pyrolysis–GCMS studies were employed to determine potential chemical products. Pyrolysis was conducted on a laboratory-scale auger reactor at 500 °C. The bio-oil and biochar yield were 28 and 46%, respectively. The pyrolysis bio-oil was characterized by the combination of GCMS, high-pressure liquid chromatography (HPLC), and electrospray ionization mass spectrometry (ESI–MS). The bio-oil was dominated by nitrogen-containing, hydrocarbons, and aromatic compounds. The biochar was studied for its specific surface area and pore size, chemical functionality by Fourier transform infrared (FTIR) and Raman spectroscopies, and butane absorption activity. Biochar was comprised of a large part of polycondensed phenolic and majorly disordered amorphous carbon. [ABSTRACT FROM AUTHOR]

The interactions between lignin and cellulose during the slow pyrolysis of their blends were studied by means of Thermogravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM). Fast pyrolysis was studied using Pyrolysis-Gas Chromatography/Mass Spectroscopy (Py–GC/MS). Crystalline cellulose (Avicel), amorphous cellulose, organosolv lignin, and their blends containing 20, 50, and 80 wt.% of lignin were used for the experiments. Differential thermogravimetry (DTG) revealed that the interaction between crystalline cellulose and lignin resulted in a shift toward higher decomposition temperatures, but for lignin/amorphous cellulose mixtures this effect was small. No effect of adding lignin to cellulose was observed on the yields of bio-char. Cellulose-lignin interactions during fast pyrolysis in Py–GC/MS did occur. Products from cellulose fragmentation reactions (hydroxyl-acetaldehyde and acetol) were not influenced by the presence of lignin. In general, production of lignin derived phenolics remains quite similar at 500 °C, but the yield of many methoxylated monophenols increases at 350 °C in the presence of both types of cellulose. Importantly, it was found that the presence of lignin enhanced the yield of levoglucosan, but decreased the yield of some of their dehydration products (e.g., levoglucosenone, 5-Hydrosymethylfurfural, Furfural). This result could be explained by the reduction of residence time of cellulose products in liquid intermediates, a phase where most of the dehydration reactions occur. Lignin seems to enhance micro-explosions, decreasing in this way the residence time of cellulose derived products in the liquid intermediates. [ABSTRACT FROM AUTHOR]

The generation of synthesis gas by catalytic partial oxidation (CPO) from renewable liquid fuels for solid oxide fuel cell applications has been the target of several studies. Typically, noble metals or nickel are employed as the active catalyst for fuel reforming, but they present drawbacks in terms of high cost and deactivation due to carbon deposition, respectively. Thermodynamically, the CPO of the model biodiesel compound, methyl oleate (C 19 H 36 O 2 ), was found to be favorable at temperatures > 800 °C. Under these conditions, we report a high catalytic activity of molybdenum dioxide (MoO 2 ) toward the reformation of methyl oleate into synthesis gas, while overcoming the disadvantages of coking and methane formation. For an O 2 /C molar ratio between 0.60 and 0.70 and a WHSV up to 10 h −1 , the CPO reaction shows a fuel carbon conversion above 80%, relatively good H 2 and CO yields, and the catalyst exhibits high redox stability. It is proposed that the lattice oxygen present in the oxide promotes the CPO reaction via the Mars–van Krevelen mechanism. [ABSTRACT FROM AUTHOR]

Production of bio-oil or biocrude from thermochemical processes such as pyrolysis and hydrothermal liquefaction (HTL) respectively, is considered a promising path for the production of alternative fuels and chemicals. However, these technologies create an aqueous phase byproduct contaminated with high concentrations of organic compounds. Traditional wastewater technologies rely on biological processing which is not resistant to the toxic levels of organic compounds present. Wet oxidation of aqueous phase byproducts is a promising processing alternative for such a dilute stream and a potential production pathway for value-added products such as acetic acid. Wet oxidation was carried out at near ambient temperature (75–90 °C) and atmospheric pressure in the presence of a hydrogen peroxide oxidant and a char catalyst activator on three individual aqueous phases. The three aqueous phases were thoroughly analyzed by total organic carbon (TOC), chemical oxygen demand (COD), Total Phenol, Total Acid Number, and individual constituents via gas chromatography with mass spectroscopy (GCMS). HTL aqueous phases were quite similar in every regard as can be seen by their COD of 44.8 and 41.5 g O 2 /L respectively. The pyrolysis aqueous phase was much more complex in nature with a 10X higher COD of 364.5 g O 2 /L. This was validated by ICRMS analysis which revealed the more complex molecules not visible by regular mass spectrometry. All the tests were conducted with a cellulose-based char catalyst doped with Nitrogen and Iron Oxide. The experiments were carried out in a microscale-based continuous reactor due to its superior continuous performance and reduction of transport limitations. Oxidation to small molecular weight compounds such as acetic acid was achieved with final products containing between 0.555 and 5.04 mg acetic acid/g liquid effluents. Our results confirm that wet oxidation is a promising process for the processing of aqueous effluents from biomass thermochemical conversion processes. [Display omitted] • Thermochemical conversion aqueous effluents are rich in organic molecules. • Wet oxidation with H 2 O 2 shows promise for reducing the toxicity of these effluents. • Microreactors with FeO- and N-doped char catalyst are utilized for wet oxidation. • Hydrothermal liquefaction (HTL) derived oligomers have broader molecular weight. • Fast pyrolysis oligomers are more recalcitrant than HTL to wet oxidation with H 2 O 2. [ABSTRACT FROM AUTHOR]

This paper investigates the effect of pyrolysis temperature between 350 and 600 °C on the distribution of pyrolytic products derived from Avicel, α-cellulose, Douglas Fir wood (softwood) and Hybrid Poplar wood (hardwood) by Py-GC/MS as a way to identify the best conditions for bio-oil production. The products were grouped in five families depending on their origin. The C1 family is formed by products of cellulose fragmentation reactions (glycoaldehyde, acetol, 1,2-ethanediol, monoacetate, butanedial). The products grouped in the C2 family (levoglucosan, levoglucosenone, 1,4:3,6-dianhydro-α- d -glucopyranose) are derived from cellulose depolymerization reactions. The molecules derived from hemicellulose (acetic acid, furfural, 2-furanmethanol) were grouped in the H family. The products derived from lignin were grouped in two families L1 (derived from p-hydroxyl phenol (H) and guaiacyl (G) structures) and L2 (derived from syringyl (S) structures). Principal components analysis was used to identify the main factors controlling the distribution of products. Our results show that the yield of most of the pyrolytic products can be explained in the five groups or families described above. Most of the C1 products derived from Avicel, α-cellulose and Douglas Fir fragmentation reactions increase in yield as the temperature increases. In the case of Hybrid Poplar these products reach a maximum at 400 °C. CO 2 , 2-oxo methyl ester propanoic acid, 1,2-cyclopentanedione, 3-methyl, levoglucosenone, 1,4:3,6-dianhydro-α- d -glucopyranose, 2,5-dimethyl-4-hydroxy-3(2H)-furanone, and most of the phenolic compounds show a response to temperature changes that is independent of the feedstock processed. As the temperature increased the yield of levoglucosenone (product of dehydration reactions) decreased for all the samples studied. Levoglucosan yield is however highly dependent on the feedstock used and, as such, its behavior with temperature changes is more difficult to predict. The maximum yield of the products derived from lignin (L1 and L2) was found between 400 and 450 °C. [ABSTRACT FROM AUTHOR]

The formation of liquid intermediates and the distribution of products were studied under slow and fast pyrolysis conditions. Results indicate that monomers are formed from lignin oligomeric products during secondary reactions, rather than directly from the native lignin. Lignin from Douglas-fir (Pseudotsuga menziesii) wood was extracted using the milled wood enzyme lignin isolation method. Slow pyrolysis using a microscope with hot-stage captured the liquid formation (>150 °C), shrinking, swelling (foaming), and evaporation behavior of lignin intermediates. The activation energy (E a) for 5–80% conversions was 213 kJ mol−1, and the pre-exponential factor (log A) was 24.34. Fast pyrolysis tests in a wire mesh reactor were conducted (300–650 °C). The formation of the liquid intermediate was visualized with a fast speed camera (250 Hz), showing the existence of three well defined steps: formation of lignin liquid intermediates, foaming and liquid intermediate swelling, and evaporation and droplet shrinking. GC/MS and UV-Fluorescence of the mesh reactor condensate revealed lignin oligomer formation but no mono-phenols were seen. An increase in pyrolytic lignin yield was observed as temperature increased. The molar mass determined by ESI-MS was not affected by pyrolysis temperature. SEM of the char showed a smooth surface with holes, evidence of a liquid intermediate with foaming; bursting from these foams could be responsible for the removal of lignin oligomers. Py-GC/MS studies showed the highest yield of guaiacol compounds at 450–550 °C. [ABSTRACT FROM AUTHOR]

Highlights: [•] A titration method to quantify strong and weak acids in bio-oil was developed. [•] The method can differentiate carboxylic acids and phenolics in bio-oils. [•] Heavy carboxylic acids represent 29–45% (mol basis) of total carboxylic acids. [•] Heavy phenolics dominated the total phenolic compounds in bio-oils. [ABSTRACT FROM AUTHOR]

Highlights: [•] In acid washed samples, sulfuric acid seems to mitigate undesirable interactions between cellulose and the other wood constituents. [•] In acid washed lignocellulosic materials there is an optimal sulfuric acid concentration that results in a 50% increase in levoglucosan production. [•] Sulfuric acid affects the pyrolysis of raw and acid washed woody biomass. [•] Dehydration and polycondensation reactions are accelerated by sulfuric acid. [•] Cellulose fragmentation reactions are mitigated by the presence of sulfuric acid. [•] Sulfuric acid reduces the yield of methoxylated mono-phenols from lignin. [Copyright &y& Elsevier]

Abstract: The effect of cellulose crystallinity on the formation of a liquid intermediate and on its thermal degradation was studied thermogravimetrically and by Py-GC/MS using a control cellulose (Avicel, crystallinity at 60.5%) and ball-milled Avicel (low cellulose crystallinity at 6.5%). The crystallinity of the materials studied was quantified by XRD and FTIR. Thermogravimetric analyses (TGA) show the samples with lower crystallinity start to degrade at lower temperatures, exhibiting sharper DTG curves and lower thermal degradation activation energies. Scanning electron microscopy (SEM) studies of the solid residues formed in TGA tests showed that, while the conversion of the ball-milled cellulose (mostly amorphous cellulose) occurs through the formation of a liquid intermediate, in the conversion of the control the fibrous structure is conserved. Py-GC/MS studies showed major differences in the thermal behavior of the samples studied. At 300°C, amorphous cellulose yielded more levoglucosan. At temperatures between 350 and 450°C, higher yields of mono-anhydrosugars (levoglucosan and levoglucosenone) were obtained with the samples with higher crystallinity (control). The ball-milled cellulose produced more 5-(hydroxymethyl) furfural, 5-methylfurfural and furfural. The higher yields of these compounds are due to the acceleration of dehydration reactions when a liquid phase intermediate was formed. Fragmentation reactions responsible for the formation of light compounds (glycoaldehyde, acetic acid, methyl-vinyl-ketone and acetol) and the reactions responsible for the formation of cyclopentane do not seem to be affected by cellulose crystallinity and by the formation of a liquid intermediate. [Copyright &y& Elsevier]

Abstract: The effect of sulfuric acid concentration on the yield and composition of bio-oils obtained from the auger and fluidized bed pyrolysis of Douglas Fir at 500°C have been investigated as a mean to enhance the production of fermentable sugars. The concentration of sulfuric acid in the feedstock was varied between 0 and 0.6mass%. The overall yield of pyrolysis products (gas, bio-oil and char) was comparable for both reactors. The presence of sulfuric acid decreases bio-oil yield and increases water and char yields. The yield of pyrolytic water produced in the auger reactor was higher due to the lower heating rates achieved which favor dehydration reactions. Maximum yields of levoglucosan and fermentable sugars were obtained at concentrations of sulfuric acid of 0.3mass% in the auger reactor and 0.05mass% in the fluidized bed reactor. Dehydration reactions responsible for water and cross linked sugars formation, as observed by the increase in the band at 1654cm−1 fitted in the FTIR, were enhanced as sulfuric acid concentration increases. The dehydration of cellulose in the presence of sulfuric acid also causes a reduction in the yield of acetic acid and acetol. The yields of some lignin derived compounds (lignin oligomers and guaiacols) also decreased substantially when sulfuric acid was added. Potential mechanisms responsible for the phenomena observed are discussed. [Copyright &y& Elsevier]

Abstract: Acid-treatment of the bio-oil from the pyrolysis of mallee leaves in methanol over a solid acid catalyst Amberlyst 70 has been investigated in this study. The reactivities of the carboxylic acids with methanol were quite different over the solid acid catalyst, which was closely related to their distinct molecular structures. The linear alkyl substituted groups, the branched alkyl substituted groups, and the aromatic carbon chain of the acids created the different steric hindrances, which negatively affected their accessibility to the catalytic sites on/in the solid acid catalyst. Similar steric effects were found in the conversion of the heavy esters into small esters via transesterification. In addition to the esterification/transesterification, the methanolysis of the olefin and decomposition of the oligomers in bio-oil occurred simultaneously during the acid treatment, which converted the reactive components into the relatively volatile and stable ones and improved the quality of the bio-oil. [Copyright &y& Elsevier]

Abstract: This paper investigates the effect of thermal pretreatment temperatures between 200 and 370°C on the yield and composition of products (bio-charm gasm water and organics) obtained when Douglas-fir wood was subsequently pyrolyzed in an auger reactor at 500°C. The yield of products was reported for the pretreatment and pyrolysis steps separately, and for the two steps added. The maximum yield of bio-oils achieved without pretreatment was close to 59mass%. A decrease in total liquid yield was observed when the biomass was pretreated at 300°C. At higher temperatures, the yields of Douglas-fir primary degradation products (lignin oligomers, anhydrosugars and alkylated and methoxylated phenols) decreased. The overall water yield increased gradually to 14mass% at a pretreatment temperature of 290°C. The yield of lignin oligomers also decreased as the pretreatment temperature increased. A drastic reduction in the yield of methoxylated phenols derived from guaiacyl (G) was observed when the biomass was pretreated at temperatures over 300°C. This drastic reduction in the yield of methoxylated lignin derivatives can be explained by the formation of liquid intermediates that facilitate the formation of ionic species, enhancing dehydration reactions leading to the production of o-quinone methide intermediates critical for bio-char formation. [Copyright &y& Elsevier]

The production of renewable fuels is a critical component of global strategies to reduce greenhouse gas (GHG) emissions. Moreover, the collection of raw materials for its production can provide added benefits such as reduction of wildfire risk, additional income for farmers, and decreased disposal costs. Although there is substantial literature on design and modeling of supply chains, the authors were unable to find a single reference with the information needed for the selection and cost estimation of each type of equipment involved in the supply chain. Therefore, the goal of this research is to gather information necessary for the construction and utilization of models that might drive the identification of a feasible supply chain to produce renewable fuels at a commercial scale. The primary objectives are to 1) understand the supply chain of critical feedstocks for renewable fuels production; 2) identify the equipment commercially available for collection and adequation of feedstock; and 3) consolidate information regarding equipment cost, energy consumption, and efficiency, as well as feedstock storage and transportation systems. This paper provides a compilation for five feedstock types studied for sustainable aviation fuel production: 1) agricultural residues and grasses, 2) forest residues, 3) urban wood waste, 4) oilseeds, 5) fats, oils & greases. All the technologies involved from the field to the gate of the preprocessing or conversion unit were reviewed. The information on fats, oils & greases supply chains and equipment purposely designed for forest thinning and pruning was very limited. • Supply chain schemes in use for five feedstock types are summarized. • Technologies involved from the field to the gate of the preprocessing or conversion unit were revised. • Equipment cost, energy consumption, and efficiency, as well as storage and transportations systems. • The information on equipment purposely designed for forest thinning and pruning was very limited. [ABSTRACT FROM AUTHOR]

A typical Dry Grind Corn Ethanol Mill (DGCEM) with a capacity of 230 ML of ethanol per year is used as the baseline for the evaluation of biorefinery concepts for sustainable aviation fuels (SFAs). The main goal is to identify SAF cost reduction opportunities as well as environmental benefits by integrating with existing DGCEM infrastructure. Five SAF production technologies are studied: Virent's BioForming (VB), Alcohol to Jet (ATJ), Direct Sugar to Hydrocarbon (DSHC), Fast Pyrolysis (FP) and Gasification & Fischer-Tropsch (GFT). We built SAF unit cases with capital cost equal to the studied DGCEM ($115 M). Larger SAF units are unlikely to synergize well with existing DGCEMs. Twelve co-location and repurposing scenarios are evaluated where SAF technologies utilize intermediate products, auxiliary facilities, or unit operations from DGCEM. For each of the scenarios, the minimum fuel selling price (MFSP) and greenhouse gas (GHG) emissions are estimated. Our aim is to identify which SAF technologies can be most efficiently integrated with a corn ethanol mill. Eleven scenarios result in lowered MFSPs in the range of 3–67% reduction, from their corresponding greenfield design cases. The highest reduction is observed when ATJ is produced in a repurposed facility. In the case of GHG we were able to identify one scenario with lower GHG emissions compared with greenfield units. SAF in thirteen scenarios have GHG emission ranging from 13 to 93% of fossil fuel. One of the repurposed scenarios of ATJ is the concept with the best overall performance parameter. Image 1 • Cost reduction for sustainable jet fuel (SAF) production in Dry Grind Corn Ethanol mills (DGCEM) were evaluated. • The integration capacities in DGCEM range from 4 million to 10 million liters of jet fuel per year. • Integration schemes for five SAF production technologies were studied with twelve co-location and repurpsoing scenarios. • Eleven integrated scenarios result in lowered fuel selling price between 3 and 67% compared with standalone. • The highest cost reduction is observed for alcohol to jet fuel produced in a repurposed facility. [ABSTRACT FROM AUTHOR]

The aviation industry has been studying strategies to produce sustainable aviation fuels (SAF) for over ten years. Our objective is to conduct detailed techno-economic analyses (TEA) of six SAF production technologies and to develop a simplified cost estimation method. Triglyceride based Hydroprocessed esters and fatty acids (HEFA) was compared against five lignocellulose-based technologies using standardized criteria. TEA was conducted to determine minimum fuel selling price (MFSP). The base case annual product capacity was fixed at 60 million liters of total fuel, for which SAF MFSPs ranged from 0.88 to 3.86 $ L−1 of fuel. Triglyceride-based HEFA had the best economic performance. Although triglycerides are more expensive than lignocellulose, HEFA is still a very competitive technology due to its high fuel yield (86–91% of feedstock) and low MFSP. Lignocellulosic-based technologies have lower fuel yields (9–23% of feedstock) due to high oxygen content of initial feedstock, resulting in higher fuel cost per unit of fuel. In order to reach a market fuel price, SAF yields from lignocellulosic materials needs to achieve an estimated value of 60%. Such yields are only possible if carbon efficiencies are close to 100%. Therefore, efforts are needed to avoid the removal of oxygen as CO 2. Based on these considerations, a new scheme is proposed for SAF production that could result in yields near those needed to achieve cost targets. This proposed integrated biomass/natural gas hybridized concepts to produce inexpensive SAFs should be thoroughly investigated in future work. • We present an estimation of fuel minimum selling price (MSP) for six technologies for jet fuel production from biomass.. • The MSP data obtained was used to calculate the aggregated conversion cost for each of the technologies. • In all the cases the conversion cost was between $200 and $450 per ton of feedstock processes.. • The fuel yield from lignocellulosic materials was in all the cases very low, close to 0.2 kg fuel/kg biomass.. • A new conversion concept is proposed that in theory can achieve theoretical fuel yields higher than 1.1 kg fuel/kg biomass. [ABSTRACT FROM AUTHOR]

• Eggshell-modified biochar shows prominent phosphorous adsorption performance. • Chemical adsorption process is the controlled step for eggshell-modified biochar. • Ca-P precipitation, hydrogen bonding, electrostatic attraction are adsorption step. • Adsorbed phosphates are mainly distributed inside pore size range of 15–50 nm. Biochar modified with calcium source is acted as an effective adsorbent for phosphorous recovery. In this research, eggshell is used as a low-cost and environmentally friendly calcium source to replace chemical reagents such as CaCO 3 , Ca(OH) 2 and CaCl 2 used in the modified biochar production. Biochar derived from rape straw and modified with eggshell shows prominent phosphorous adsorption performance (e.g., equilibrium adsorption amount, 109.7 mg/g). The kinetic and isotherm analysis demonstrate that chemical adsorption process is performed as the main controlled step for the modified biochar adsorption, and the phosphate adsorption process is composed of both monolayer adsorption and multi-layer adsorption. Moreover, it is found from the physicochemical structures comparison before and after phosphate adsorption that Ca-P precipitation, hydrogen bonding and electrostatic attraction are identified as main adsorption mechanisms. In addition, the adsorbed phosphates are mainly distributed inside the space with pore sizes of 15–50 nm. [ABSTRACT FROM AUTHOR]

Wet oxidation can be an effective process for the pretreatment of complex biomass such as lignocellulose. However, studies on the use of wet oxidation for treating solid waste such as dairy manure are limited. The use of partial wet oxidation to convert dairy manure into low molecular weight carboxylic acids as final products were investigated. This work focuses on the performance of the sub-critical wet oxidation treatment of dairy cattle manure as a conversion/pretreatment process to release matter from the lignocellulosic fraction rather than a destructive process. The operating conditions were controlled at the short residence time and optimal temperature in the presence of oxygen under a pressure of 120 psi. The thermal hydrolysis under wet oxidation significantly affected conversion manure slurry into organic acids. The concentration of acetic acid reached 1778 mg L -1 , achieved at 190°C (60 minutes reaction time) as the reaction temperature increased within the range of 150°C-200°C, total organic carbon was reduced and monomers in the process liquids decreased. On the other hand, soluble COD in process liquids increased with an increment in reaction temperature. The results provide insights into technical options to pretreat dairy manure to improve biochemical conversion yield., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Due to phosphate's necessity in agriculture and its danger to the environment, the development of adsorbents for its removal has been the subject of intensive research activity. Although the introduction of nitrogen functionality to chars and modification of biochar with metals have proven to change the character of the char structure, making it more active toward nutrients, there is no study regarding the doping of biochar with metals and nitrogen simultaneously for the adsorption of phosphates. This paper is the first of two in which we report the production, characterization, and evaluation of N-metal-doped biochars from cellulose for phosphate removal from liquid effluents. In this part, we describe the production and characterization of N-Ca-, N-Fe-, and N-Mg-doped biochars. The elemental composition and surface area of each of the materials produced is reported. Elemental and surface characterization of the chars are reported with the largest N content appearing at a temperature of 800 °C (12.5 wt %) and a maximum surface area for biochar produced at 900 °C (1314 m 2 /g). All of the adsorbents were visualized by scanning electron microscope (SEM), confirming that although there are some crystals on the surface of the biochar produced, most of the N, Mg, and Ca are part of the polyaromatic ring structure. Transmission electron microscope (TEM) images clearly show the formation of nanoclusters with the metals in the case of N-Fe and N-Ca biochars. The N-Mg biochars show a uniform distribution of the Mg through the carbon surface. X-ray photoelectron spectroscopy (XPS) studies of the biochars produced with metals and varying nitrogen levels clearly show Mg and Ca peaks shifting their position in the presence of N, suggesting the formation of stable structures between metals and N in the carbon polyaromatic ring system. To elucidate the nature of these structures, we conducted DFT-based calculations on different configurations of the nitrogenated structures. The calculated binding energy shifts were found to closely match the XPS experimental binding energy, confirming the likelihood of these structures in biochar. Finally, based on our experimental and modeling results, we hypothesize that an important fraction of the Mg and Ca is introduced to these biochars at the edges. Another fraction of Mg and Ca is in the form of phthalocyanine-like internal structures. More experimental studies are needed to confirm the formation of these very interesting structures and their potential use as adsorbents or catalysts., Competing Interests: The authors declare no competing financial interest., (© 2022 The Authors. Published by American Chemical Society.)