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This work evaluates the effect of feedstock type and composition on the conversion of lignin to liquid by solvolysis with formic acid as hydrogen donor (LtL), by analyzing the yields and molecular composition of the liquid products and interpreting them in terms of both the type and the preprocessing of the lignocellulosic biomass using chemometric data analysis. Lignin samples of different types and purities from softwood, hardwood, and grasses (rice straw and corn stover) have been converted to bio-oil, and the molecular composition analyzed and quantified using GC-MS. LtL solvolysis was found to be a robust method for lignin conversion in terms of converting all samples into bio-oils rich in phenolic compounds regardless of the purity of the lignin sample. The bio-oil yields ranged from 24–94 wt.% relative to lignin input and could be modelled well as a function of the elemental composition of the feedstock. On a molecular basis, the softwood-derived bio-oil contained the most guaiacol-derivatives, and syringol was correlated to hardwood. However, the connection between compounds in the bio-oil and lignin origin was less pronounced than the effects of the methods for biomass fractionation, showing that the pretreatment of the biomass dominates both the yield and molecular composition of the bio-oil and must be addressed as a primary concern when utilization of lignin in a biorefinery is planned. [ABSTRACT FROM AUTHOR]

Background: Over the last few years, valorization of lignocellulosic biomass has been expanded beyond the production of second-generation biofuels to the synthesis of numerous platform chemicals to be used instead of their fossil-based counterparts. One such well-researched example is 5-hydroxymethylfurfural (HMF), which is preferably produced by the dehydration of fructose. Fructose is obtained by the isomerization of glucose, which in turn is derived by the hydrolysis of cellulose. However, to avoid harsh reaction conditions with high environmental impact, an isomerization step towards fructose is necessary, as fructose can be directly dehydrated to HMF under mild conditions. This work presents an optimized process to produce fructose from beechwood biomass hydrolysate and subsequently convert it to HMF by employing homogeneous catalysis. Results: The optimal saccharification conditions were identified at 10% wt. solids loading and 15 mg enzyme/gsolids, as determined from preliminary trials on pure cellulose (Avicel® PH-101). Furthermore, since high rate glucose isomerization to fructose requires the addition of sodium tetraborate, the optimum borate to glucose molar ratio was determined to 0.28 and was used in all experiments. Among 20 beechwood solid pulps obtained from different organosolv pretreatment conditions tested, the highest fructose production was obtained with acetone (160 °C, 120 min), reaching 56.8 g/100 g pretreated biomass. A scale-up hydrolysis in high solids (25% wt.) was then conducted. The hydrolysate was subjected to isomerization eventually leading to a high-fructose solution (104.5 g/L). Dehydration of fructose to HMF was tested with 5 different catalysts (HCl, H3PO4, formic acid, maleic acid and H-mordenite). Formic acid was found to be the best one displaying 79.9% sugars conversion with an HMF yield and selectivity of 44.6% and 55.8%, respectively. Conclusions: Overall, this work shows the feasibility of coupling bio- and chemo-catalytic processes to produce HMF from lignocellulose in an environmentally friendly manner. Further work for the deployment of biocatalysts for the oxidation of HMF to its derivatives could pave the way for the emergence of an integrated process to effectively produce biobased monomers from lignocellulose. [ABSTRACT FROM AUTHOR]

The catalytic performance of a set of technical, zeolite ZSM‐5 extruded materials have been studied in a bench scale unit for the ex‐situ Catalytic Fast Pyrolysis (CFP) of lignocellulosic biomass. The set of catalysts include micro‐ and mesoporous materials, with and without ZrO2‐promotion, with different Si/Al ratios and with micro‐ and nanosized zeolite crystals. Mesoporosity, acidity and crystal size play a key role on the overall catalytic performances in terms of activity and selectivity (i. e., in their ability to obtain the highest bio‐oil fraction with the lowest oxygen content), and also importantly, stability. Detailed post‐mortem bulk and micro‐spectroscopic studies of the solid catalysts complement the catalytic testing. The obtained results point towards coke deposits as the main cause for catalyst deactivation. Details of the nature, formation and evolution of these coke deposits revealed essential insights, which serve to evaluate the design of catalysts for the ex‐situ CFP of biomass. In particular the mesoporous catalysts are overall better preserved with increasing time‐on‐stream and deactivate later than their microporous counterparts, which suffer from pore blockage. Likewise, it was seen that ZrO2‐promotion contributed positively in the prevention against deactivation by hard coke spreading, thanks to its enhanced Lewis acidity. The zeolite's crystal size is another important characteristic to combine the different components within catalyst bodies, ensuring the proper interaction between zeolite, promoter and binder. This is illustrated by the nanocrystalline ZrO2/n‐ZSM‐5‐ATP material, which shows the best catalytic performance. [ABSTRACT FROM AUTHOR]

Ex situ catalytic biomass pyrolysis was investigated at both laboratory and bench scale by using a zeolite ZSM‐5‐based catalyst for selectively upgrading the bio‐oil vapors. The catalyst consisted of nanocrystalline ZSM‐5, modified by incorporation of ZrO2 and agglomerated with attapulgite (ZrO2/n‐ZSM‐5‐ATP). Characterization of this material by means of different techniques, including CO2 and NH3 temperature‐programmed desorption (TPD), NMR spectroscopy, UV/Vis microspectroscopy, and fluorescence microscopy, showed that it possessed the right combination of accessibility and acid–base properties for promoting the conversion of the bulky molecules formed by lignocellulose pyrolysis and their subsequent deoxygenation to upgraded liquid organic fractions (bio‐oil). The results obtained at the laboratory scale by varying the catalyst‐to‐biomass ratio (C/B) indicated that the ZrO2/n‐ZSM‐5‐ATP catalyst was more efficient for bio‐oil deoxygenation than the parent zeolite n‐ZSM‐5, producing upgraded bio‐oils with better combinations of mass and energy yields with respect to the oxygen content. The excellent performance of the ZrO2/n‐ZSM‐5‐ATP system was confirmed by working with a continuous bench‐scale plant. The scale‐up of the process, even with different raw biomasses as the feedstock, reaction conditions, and operation modes, was in line with the laboratory‐scale results, leading to deoxygenation degrees of approximately 60 % with energy yields of approximately 70 % with respect to those of the thermal bio‐oil. [ABSTRACT FROM AUTHOR]

A simple and efficient hydrodeoxygenation strategy is described to selectively generate and separate high-value alkylphenols from pyrolysis bio-oil, produced directly from lignocellulosic biomass. The overall process is efficient and only requires low pressures of hydrogen gas (5 bar). Initially, an investigation using model compounds indicates that MoC x/C is a promising catalyst for targeted hydrodeoxygenation, enabling selective retention of the desired Ar−OH substituents. By applying this procedure to pyrolysis bio-oil, the primary products (phenol/4-alkylphenols and hydrocarbons) are easily separable from each other by short-path column chromatography, serving as potential valuable feedstocks for industry. The strategy requires no prior fractionation of the lignocellulosic biomass, no further synthetic steps, and no input of additional (e.g., petrochemical) platform molecules. [ABSTRACT FROM AUTHOR]

In situ catalytic fast pyrolysis can be used to produce partially upgraded bio-oils. This process, however, suffers from rapid catalyst deactivation caused by coke formation, which necessitates the use of continuous catalyst regeneration. This can be achieved by using a circulating fluidized-bed reactor. In such a reactor, one key operational variable is the catalyst-to-biomass (C/B) ratio, which influences the extent of the catalytic reactions that take place. In this study, woody biomass is pyrolyzed in a pilot-scale circulating fluidized-bed reactor system using a HZSM-5 zeolite with varying C/B ratios. The C/B ratio influences the overall product distribution, the elemental distribution, and the characteristics of the liquid products. An increase of the C/B ratio enhances the conversion of pyrolysis vapors but this does not result in a continuous improvement in bio-oil quality. The C/B ratio is, nevertheless, a factor that can be used to optimize the catalytic fast pyrolysis process. [ABSTRACT FROM AUTHOR]

The aqueous phase resulting from the catalytic pyrolysis (AQcatPy) of biomass has been successfully applied for acidification of urea-formaldehyde (UF) resins. The resins were synthesized at a laboratory scale and characterized by gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The bonding ability of the resins was tested through the preparation of particle boards (PBs). It was found that the UF resins prepared with AQcatPy as acidification medium have a similar performance to typical UF resins, where conventional chemicals like formic acid (FA) or acetic acid (AA) serve for pH adjustments. The new resins give PBs with somewhat improved thickness swelling (TS) values, while all other properties are at the same level. [ABSTRACT FROM AUTHOR]

Bio-oil (pyrolysis oil) is the liquid product of biomass thermochemical conversion. It is a dark, viscous liquid that contains the depolymerization products of hemicellulose, cellulose, and lignin. The physicochemical properties of bio-oils are determined by employing the conventional methods for fuels analysis with proper adaptations. However, the detailed composition of bio-oils in terms of analytes as well as their concentration remains ambiguous and is a challenging task for analytical chemistry. The compounds in the bio-oil range from nonpolar (e.g., hydrocarbons) to highly polar (e.g., phenolics) and from volatile (e.g., organic acids) to nonvolatile (e.g., sugar derivatives), covering a molecular weight (MW) range of about 50-2000 Da. Hence a combination of analytical techniques such as high pressure liquid chromatography, gas chromatography ( GC), gel permeation chromatography (GPC), nuclear magnetic resonance spectroscopy ( NMR), and Fourier transform infrared spectroscopy (FTIR) are required to determine the bio-oil's composition. Despite the significant breakthroughs of these techniques, they face limitations regarding the sample pretreatment, the incomplete separation and determination of components, and the need of multiple analyses with each method for more complete results. The development of sophisticated, comprehensive, and hyphenated chromatographic and spectrometric techniques such as GC × GC, LC × LC, high-resolution mass spectrometry ( HRMS), and 2D-NMR has brought actual advancement in the field of bio-oil analysis. GC × GC and LC × LC have allowed the development of qualitative and quantitative methods for the individual determination of lower MW compounds. However, HRMS and 2D-NMR have facilitated the elucidation of the structure of the higher MW components, offering insight in the effect of pyrolysis conditions on biomass depolymerization and the possibilities for further upgrading of bio-oils. WIREs Energy Environ 2016, 5:614-639. doi: 10.1002/wene.208 For further resources related to this article, please visit the . [ABSTRACT FROM AUTHOR]

Abstract: MCM-41, is one of the latest members of the mesoporous family of materials. They possess a hexagonal array of uniform mesopores (1.4–10nm), high surface areas (>1000m2/g) and moderate acidity. Due to these properties the MCM-41 materials are currently under study in a variety of processes as catalysts or catalyst supports. The objective of this study was to evaluate different types of MCM-41 materials as potential catalysts in the catalytic biomass pyrolysis process. We expected that the very high pore size and the mild acidity of these materials could be beneficial to reformulate the high molecular weight primary molecules from biomass pyrolysis producing useful chemical (and especially phenolic compounds) and lighter bio-oil with less heavy molecules. Three different samples of Al-MCM-41 materials (with different Si/Al ratio) and three metal containing mesoporous samples (Cu–Al-MCM-41, Fe–Al-MCM-41 and Zn–Al-MCM-41) have been synthesised, characterized and tested as catalysts in the biomass catalytic pyrolysis process using a fixed bed pyrolysis combined with a fixed catalytic reactor and two different types of biomass feeds. Compared to conventional (non-catalytic) pyrolysis, it was found that the presence of the MCM-41 material alters significantly the quality of the pyrolysis products. All catalysts were found to increase the amount of phenolic compounds, which are very important in the chemical (adhesives) industry. A low Si/Al ratio was found to have a positive effect on product yields and composition. Fe–Al-MCM-41 and Cu–Al-MCM-41 are the best metal-containing catalysts in terms of phenols production. The presence of the Al-MCM-41 material was also found to decrease the fraction of undesirable oxygenated compounds in the bio-oil produced, which is an indication that the bio-oil produced is more stable. [Copyright &y& Elsevier]

Biomass fractionation, as an alternative to biomass pretreatment, has gained increasing research attention over the past few years as it provides separate streams of cellulose, hemicellulose, and lignin. These streams can be used separately and can provide a solution for improving the economics of emerging biorefinery technologies. The sugar streams are commonly used in microbial conversions, whereas during recent years lignin has been recognized as a valuable compound as it is the only renewable and abundant source of aromatic chemicals. Successfully converting lignin into valuable chemicals and products is key in achieving both environmental and economic sustainability of future biorefineries. In this work, lignin retrieved from beechwood sawdust delignification pretreatment via an organosolv process was depolymerized with thermal and catalytic pyrolysis. ZSM-5 commercial catalyst was used in situ to upgrade the lignin bio-oil vapors. Lignins retrieved from different modes of organosolv pretreatment were tested in order to evaluate the effect that upstream pretreatment has on the lignin fraction. Both thermal and catalytic pyrolysis yielded oils rich in phenols and aromatic hydrocarbons. Use of ZSM-5 catalyst assisted in overall deoxygenation of the bio-oils and enhanced aromatic hydrocarbons production. The oxygen content of the bio-oils was reduced at the expense of their yield. Organosolv lignins were successfully depolymerized towards phenols and aromatic hydrocarbons via thermal and catalytic pyrolysis. Hence, lignin pyrolysis can be an effective manner for lignin upgrading towards high added value products. [ABSTRACT FROM AUTHOR]

Abstract In this work, we investigated the deactivation of a commercial ZSM-5 based catalyst during ex situ catalytic fast pyrolysis (CFP). The experimental runs were carried out in a novel cascade dual fluidized bed reactor system where thermal pyrolysis of biomass was carried out in the first reactor, while ex situ catalytic conversion of the pyrolysis vapours was carried out in the second reactor. Consecutive reaction-regeneration cycles were realised using the same catalyst batch in order to evaluate catalyst deactivation over time. A comparison between in situ and ex situ CFP revealed that in contrast to what was observed in the case of in situ CFP, no accumulation of biomass-derived metals on the catalyst was observed during ex situ CFP. Both acidity and surface area were less affected compared to in situ CFP and the catalyst maintained higher activity. Product distribution and composition exhibited some variation over time which was attributed to the accumulation of biomass ash in the pyrolysis reactor and not to the poisoning of the catalyst bed. These results clearly demonstrated that ex situ CFP is an effective way to avoid catalyst poisoning during the CFP of biomass and to prolong catalyst lifetime. Graphical abstract Unlabelled Image Highlights • Biomass ex situ catalytic pyrolysis took place in a cascade reactor system. • Consecutive reaction-regeneration runs led to changes in product yields and quality. • Biomass alkalis did not accumulate on catalyst in ex situ runs prolonging its life. • Catalyst properties and activity were much less affected in ex situ runs. [ABSTRACT FROM AUTHOR]

Abstract: Seven mesoporous catalysts were compared in how they can convert the pyrolysis vapours of spruce wood in order to obtain improved bio-oil properties. Four Al-MCM-41 type catalysts with a Si/Al ratio of 20, a commercial FCC catalyst, a pure siliceous SBA-15 and an aluminium incorporated SBA-15 materials were tested. The catalytic properties of Al-MCM-41 catalyst were modified by pore enlargement that allows the processing of larger molecules and by introduction of Cu cations into the structure. Spruce wood pyrolysis at 500°C was performed in a lab-scale fixed bed reactor, the solid, gaseous and liquid products were separated and the gases and the organic part of the liquids were analysed with the help of gas chromatography and mass spectrometry. The gas yield increased in each catalytic case, the coke yield remained the same or slightly decreased compared to the non-catalytic experiments. The aqueous part in the liquid phase increased in the catalytic runs. The obtained products in the organic phase were grouped into eight groups and further into desirable and undesirable product groups, and the yields were evaluated. In the catalytic experiments the hydrocarbon and acid yields increased, while the carbonyl and the acid yields decreased. All catalysts tested reduced the undesirable product yield, while the desirable product yield remained the same or increased. To study the feedstock effect on the catalytic upgrading of the pyrolysis vapours, some tests were performed with Miscanthus biomass. With spruce the FCC, with Miscanthus the unmodified Al-MCM-41 are the best performing catalysts. Concerning the feedstocks, with Miscanthus a better quality bio-oil has been obtained. [Copyright &y& Elsevier]

Lignocellulosic biomass contains inorganic elements (ash) that are known to act catalytically during fast pyrolysis and result in a decrease of the process' selectivity towards the desired liquid product. In this work, the removal of inorganic elements from two forestry residues, two agricultural residues and two energy crops was studied with the aim to maximize the liquid product yield from the fast pyrolysis process. The biomass samples were washed with water and solutions of nitric or acetic acid and the effects of time, temperature, acid type and acid concentration in the washing solution were studied. The original and the pretreated biomass samples were then pyrolyzed in a bench-scale fixed bed reactor in order to investigate the effects of the demineralization on the yields and composition of the pyrolysis products. Washing with water was effective for the removal of up to 42% of the inorganics in the biomass samples, whereas washing with acidic solutions achieved inorganics removal higher than 90%. The most important factor during the biomass pretreatment proved to be the washing temperature; higher temperatures (50 °C) were more effective for the removal of the inorganics than room temperature. The type of acid used in the washing solution was also an important factor, as nitric acid proved to be more effective than acetic acid. In the pyrolysis experiments, the demineralized biomass samples yielded less gas products and solid residue, while the selectivity towards the liquid product was substantially increased in all cases. [ABSTRACT FROM AUTHOR]

Thermal and catalytic pyrolysis of various types of lignin and their influence on the yield and the quality of the produced lignin oil were studied. Lignins originated from a mixture of pine and spruce wood (softwood), a mixture of birch and aspen wood (hardwood) and Eucalyptus Urograndis. High degree of deoxygenation of the bio-oil and maximum yield of value-added chemicals were the main targets of this work. 2DGC-ToFMS analysis was used for the qualitative and quantitative characterization of the lignin oils. Softwood lignin was found to be the most attractive feedstock and high yields of a mixture of phenolic compounds were detected in all cases. High char production was also evident for all types of lignins accounting for almost 50% of the original feedstock. The use of a commercial ZSM-5 catalyst was extremely beneficial for the process, enhancing deoxygenation at higher oil yields compared to thermal pyrolysis. Depending on the nature of the lignin, guaiacyl or syringyl groups were dominant in the oils and it was found that process optimization, involving lignin, catalyst selection and temperature could significantly improve the process efficiency. [ABSTRACT FROM AUTHOR]

Highlights: [•] Pyrolysis of biomass component mixtures in both TGA and pyrolysis reactor setups. [•] Comparison between experimental and calculated product yields and composition. [•] Heat transfer lag was evident during the pyrolysis of biomass component mixtures. [•] Elucidation of thermal and catalytic reaction pathways of each biomass component. [ABSTRACT FROM AUTHOR]

Abstract: The mesoporous material Al-MCM-41 has previously been reported to exhibit interesting catalytic properties during the pyrolysis of wooden based biomass. In this work, four materials with Si:Al ratio of 20, have been investigated, a parent Al-MCM-41 and Me–Al-MCM-41 (Me being Fe, Cu and Zn). The materials have been fully characterized in order to obtain structural information about the local metal surroundings, by XRD, nitrogen absorption isotherms, 27Al-MAS-NMR and XAS. Results have shown that the metal sitings are different in these materials, in that iron is tetrahedrally coordinated, substituting for aluminium in the walls of the mesoporous material, while copper is present as an extra phase, forming CuO upon calcination. The EXAFS-spectra for Zn–Al-MCM-41 have shown that the material remains unchanged upon calcination, with no sintering of zinc, indicating a framework siting. However, two Zn…Si distances show a higher degree of disorder than in the iron-containing sample. The catalysts are all shown to improve the product distribution and the quality of the bio-oil with respect to the yield of phenols. The presence of Zn–Al-MCM-41 as the catalyst leads to the lowest yield of phenols, but this catalyst gives the best results with respect to reduction of coke produced. The investigations have shown that these mesoporous materials are promising catalysts for the pyrolysis of biomass, and that the type of metal is of more importance than the metal siting. [Copyright &y& Elsevier]

[Display omitted] • OxiOrganosolv with isobutanol as solvent was used for beechwood pretreatment. • High delignification rates, up to 97%, were achieved. • Around 50 wt% of initial hemicellulose was recovered as XOS in the liquid fraction. • Enzymatic hydrolysate supported C. cohnii growth and lipid accumulation (~52 wt%) • Up to 51.6 g /L (0.57 g/g biomass) D-lactic acid was produced through SSF. The aim of this work was to investigate the use of isobutanol as organic solvent for the efficient delignification and fractionation of beechwood through the OxiOrganosolv process in the absence of any catalyst. The results demonstrate that cellulose-rich solid pulp produced after pretreatment is a source of fermentable sugars that can be easily hydrolyzed and serve as a carbon source in microbial fermentations for the production of omega-3 fatty acids and D-lactic acid. The C5 sugars are recovered in the aqueous liquid fractions and comprise a fraction rich in xylo -oligosaccharides with prebiotic potential. The maximum production of optically pure D-lactic from Lactobacillus delbrueckii sp. bulgaricus reached 51.6 g/L (0.57 g/g biomass), following a simultaneous saccharification and fermentation strategy. Crypthecodenium cohnii accumulated up to 52.1 wt% lipids with a DHA content of 54.1 %, while up to 43.3 % hemicellulose recovery in form of oligosaccharides was achieved in the liquid fraction. [ABSTRACT FROM AUTHOR]