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Catalytic Acylation Hydrogenation And Hydrodeoxygenation Of Lignin Derived Aromatic Molecules
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Book Synopsis Catalytic Acylation, Hydrogenation and Hydrodeoxygenation of Lignin-derived Aromatic Molecules by : Nhung N. Duong
Download or read book Catalytic Acylation, Hydrogenation and Hydrodeoxygenation of Lignin-derived Aromatic Molecules written by Nhung N. Duong and published by . This book was released on 2018 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Lignin Conversion Catalysis by : Chaofeng Zhang
Download or read book Lignin Conversion Catalysis written by Chaofeng Zhang and published by John Wiley & Sons. This book was released on 2022-08-19 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lignin Conversion Catalysis Authoritative reference providing comprehensive knowledge on the lignin conversion process with recent developments of mechanisms and techniques Lignin Conversion Catalysis: Transformation to Aromatic Chemicals covers the strategy, catalysis, and mechanisms of cleaving lignin linkages to aromatic chemicals and crucially elaborates on the specifics of multiple original lignins. Sample topics covered in the work include: Lignin depolymerization, models, and techniques of various lignins by heterogeneous substrates (such as native lignins, Kraft lignins, and organosolv lignins) Cleavage methods for lignins (such as oxidation and hydrogenation) as well as their main products (such as arenes, phenol, and acid) Relationships among the strategy/method, catalyst, and mechanism when viewed from the cleavage order and the type of corresponding chemical bonds Commercial components of lignin, a globally available raw material with many applications in drug design, polymers, and more Organic chemists, polymer chemists, and chemical engineers can use the valuable information contained in Lignin Conversion Catalysis: Transformation to Aromatic Chemicals to get up to date on this new raw material and understand the various developments that have been made in the field to make it viable for industrial purposes.
Book Synopsis Hydrodeoxygenation of Lignin-derived Model Compounds Over Oxide Supported Pt Catalysts by : Alexander Michael Long
Download or read book Hydrodeoxygenation of Lignin-derived Model Compounds Over Oxide Supported Pt Catalysts written by Alexander Michael Long and published by . This book was released on 2015 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Chemical Catalysts for Biomass Upgrading by : Mark Crocker
Download or read book Chemical Catalysts for Biomass Upgrading written by Mark Crocker and published by John Wiley & Sons. This book was released on 2020-03-09 with total page 634 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive reference to the use of innovative catalysts and processes to turn biomass into value-added chemicals Chemical Catalysts for Biomass Upgrading offers detailed descriptions of catalysts and catalytic processes employed in the synthesis of chemicals and fuels from the most abundant and important biomass types. The contributors?noted experts on the topic?focus on the application of catalysts to the pyrolysis of whole biomass and to the upgrading of bio-oils. The authors discuss catalytic approaches to the processing of biomass-derived oxygenates, as exemplified by sugars, via reactions such as reforming, hydrogenation, oxidation, and condensation reactions. Additionally, the book provides an overview of catalysts for lignin valorization via oxidative and reductive methods and considers the conversion of fats and oils to fuels and terminal olefins by means of esterification/transesterification, hydrodeoxygenation, and decarboxylation/decarbonylation processes. The authors also provide an overview of conversion processes based on terpenes and chitin, two emerging feedstocks with a rich chemistry, and summarize some of the emerging trends in the field. This important book: -Provides a comprehensive review of innovative catalysts, catalytic processes, and catalyst design -Offers a guide to one of the most promising ways to find useful alternatives for fossil fuel resources -Includes information on the most abundant and important types of biomass feedstocks -Examines fields such as catalytic cracking, pyrolysis, depolymerization, and many more Written for catalytic chemists, process engineers, environmental chemists, bioengineers, organic chemists, and polymer chemists, Chemical Catalysts for Biomass Upgrading presents deep insights on the most important aspects of biomass upgrading and their various types.
Book Synopsis Catalytic Conversion of Lignin-derived Compounds to Fuels and Chemicals by : Tarit Nimmanwudipong
Download or read book Catalytic Conversion of Lignin-derived Compounds to Fuels and Chemicals written by Tarit Nimmanwudipong and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The environmental problems caused by the production and usage of non-renewable fossil fuels has encouraged scientists to conduct research on alternative fuels. Lignocellolusic biomass is considered one of the most promising resources of alternative liquid fuels as well as renewable chemicals. Among several potential routes for biomass conversion, fast pyrolysis and subsequent catalytic upgrading has gained interest widely. Although the combination involves minimum numbers of steps, the cost of resultant fuels and chemicals is not yet low. Therefore, research is needed for better understanding of the process. This study considered the potential use of "bio-oils", product from fast pyrolysis of lignin, the under-utilized part of lignocellulose, as possible aromatic chemical and fuel feedstock source with the key challenge being the removal of excessive oxygen. The literature of catalytic upgrading of lignin-derived bio-oils is still lacking fundamental chemistry. Detailed and quantitative information about the products, the important reaction pathways, and kinetics is limited, but vital as basis for predicting catalyst choices and designing processes. Thus, our goal was to provide such information and to begin unraveling the chemistry of conversion of oxygenate molecules characteristic of lignin-derived bio-oils--and specifically to understand crucial catalytic oxygen-removal reactions. We investigated the conversion of prototypical compounds that represent important components in lignin-derived bio-oils. The reactions were catalyzed by a solid acid (HY zeolite) and supported metals (Pt/[gamma]-Al2O3), which are typical in petroleum and petrochemical industries. This dissertation addresses catalytic reactions of guaiacol, cyclohexanone, and eugenol. For the first time in this field, our data determine quantitative conversion, selectivity of the products, and approximate kinetics of the primary products in the reactions with Pt/[gamma]-Al2O3. The results show that four major reaction classes including transalkylation, hydrogenation, hydrogenolysis, and hydrodeoxygenation were dominant. Without H2 as a reactant and a metal function in the catalyst, transalkylation was the only important reaction class as observed in the conversion catalyzed by acidic HY zeolite. Higher H2 partial pressure led to higher selectivity of oxygen removal products in the conversion catalyzed by Pt/[gamma]-Al2O3. The data identify the role of catalyst functions and imply that a supported-metal catalyst and high pressure H2 will be necessary for oxygen removal of compounds found in lignin-derived bio-oils. Catalyst deactivation was usually observed in the conversion with HY zeolite and Pt/[gamma]-Al2O3. The earlier results indicate that acid sites of the catalysts were associated with the formation of carbonaceous materials on those catalysts. Therefore, the conversion of guaiacol catalyzed by basic supported platinum (Pt/MgO) was investigated. The data show that Pt/MgO deactivated less rapidly compared to other catalysts. The corresponding selectivity to oxygen removal products was nearly doubled the value observed from the reactions catalyzed by Pt/[gamma]-Al2O3, demonstrating potential value of basic support for selective HDO process. In summary, results obtained from this research lead to better understanding of catalytic conversion of lignin-derived compounds. Extrapolation of these understanding will help predicting catalyst performance in the upgrading of bio-oils and ultimately designing suitable catalysts and optimizing operating conditions for the conversion of lignin to fuels and chemicals.
Book Synopsis Reaction Pathways and Mechanisms in Thermocatalytic Biomass Conversion II by : Marcel Schlaf
Download or read book Reaction Pathways and Mechanisms in Thermocatalytic Biomass Conversion II written by Marcel Schlaf and published by Springer. This book was released on 2015-10-30 with total page 206 pages. Available in PDF, EPUB and Kindle. Book excerpt: Volume II presents the latest advances in catalytic hydrodeoxygenation and other transformations of some cellulosic platform chemicals to high value-added products. It presents the theoretical evaluation of the energetics and catalytic species involved in potential pathways of catalyzed carbohydrate conversion, pathways leading to the formation of humin-based by-products, and thermal pathways in deriving chemicals from lignin pyrolysis and hydrodeoxygenation. Catalytic gasification of biomass under extreme thermal conditions as an extension of pyrolysis is also discussed. Marcel Schlaf, PhD, is a Professor at the Department of Chemistry, University of Guelph, Canada. Z. Conrad Zhang, PhD, is a Professor at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences, China.
Book Synopsis Base-catalyzed Depolymerization of Lignin and Hydrodeoxygenation of Lignin Model Compounds for Alternative Fuel Production by : Mariefel Valenzuela Olarte
Download or read book Base-catalyzed Depolymerization of Lignin and Hydrodeoxygenation of Lignin Model Compounds for Alternative Fuel Production written by Mariefel Valenzuela Olarte and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study considered the potential use of lignin as possible renewable fuel and chemical feedstock source. Among the various polymers present in lignocellulosic biomass, the polyaromatic lignin is the one component that is most chemically similar to petroleum. However, it still contains a much larger amount of oxygen compared to crude oil. As such, two strategies were employed in this study: (1) studying the lignin depolymerization in the presence of high temperature and base catalysts; and, (2) employing hydrodeoxygenation as a means to decrease the O/C ratio in lignin-derived model compounds. The base-catalyzed depolymerization (BCD) of organosolv lignin was done in a 500-mL Monel Parr reactor at temperatures ranging from 165°C to 350°C. Complete solubilization of lignin derivatives was possible in the presence of NaOH and KOH, except at 350°C. NMR experiments revealed formation of oxidized groups (carboxylic and hydroxyl groups) as well as alkyl groups. On the other hand, the use of NH4OH showed N incorporation. Identified and quantified DCM-soluble monomeric compounds were at most 6% of the starting material and are mainly phenolic. This study revealed the apparent susceptibility of syringyl units over guaiacyl units in BCD. This could in turn guide the choice of substrate on which base-catalyzed depolymerization could be applied. Syringaldehyde was used as the starting material to study batch hydrodeoxygenation (HDO) using several non-cobalt/molybdenum based catalysts. A 50-ml Parr reactor was used, pressurized by 1000 psig of H2 and heated to 300°C. Nickel based catalysts (nickel phosphide, nickel oxide and nickel phosphate) as well as supported precious metals (Pt and Pd) were tested as HDO catalysts. Of the three O-containing functional groups of syringaldehyde, the aldehydic group was found to be the most susceptible. In the presence of the Al2O3-supported catalysts, the methyl groups liberated were found to be incorporated back into the aromatic ring, forming alkylated compounds. In the last section of this dissertation, hydrothermally synthesized supported Ni on mesoporous silica (MCF) and acid catalysts (HY and H-Al-MCF) were used for probing the effect of bifunctional metal-acid catalysis on phenol hydrodeoxygenation/hydrogenation. Catalyst configurations were varied from the previously studied wet-impregnated Pt/HY catalyst. Based on a hypothesis that coking catalyzed by the acidic zeolite in the wet impregnated Pt/HY catalyst was the main cause of catalyst deactivation and decreased phenol conversion, separately synthesized metal and acid catalyst systems were tested. Complete phenol conversion was sustained for at least three times longer in a continuous flow reactor operated at 200°C and 0.79 MPa of flowing H2. The separation of the metal and acid sites generated a tunable system capable of producing cyclohexanol, cyclohexane or cyclohexene at very high selectivities, even achieving 99% selectivities for cyclohexane.
Book Synopsis Catalytic Hydrogenation for Biomass Valorization by : Roberto Rinaldi
Download or read book Catalytic Hydrogenation for Biomass Valorization written by Roberto Rinaldi and published by Royal Society of Chemistry. This book was released on 2015 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: As the biorefinery industry expands to meet the latest discoveries in biomass conversion, this book provides a thorough grounding in the subject.
Book Synopsis Catalytic Processes for The Valorisation of Biomass Derived Molecules by : Francesco Mauriello
Download or read book Catalytic Processes for The Valorisation of Biomass Derived Molecules written by Francesco Mauriello and published by MDPI. This book was released on 2019-11-22 with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last decades, inedible lignocellulosic biomasses have attracted significant attention for being abundant resources that are not in competition with agricultural land or food production and, therefore, can be used as starting renewable material for the production of a wide variety of platform chemicals. The three main components of lignocellulosic biomasses are cellulose, hemicellulose and lignin, complex biopolymers that can be converted into a pool of platform molecules including sugars, polyols, alchols, ketons, ethers, acids and aromatics. Various technologies have been explored for their one-pot conversion into chemicals, fuels and materials. However, in order to develop new catalytic processes for the selective production of desired products, a complete understanding of the molecular aspects of the basic chemistry and reactivity of biomass derived molecules is still crucial. This Special Issue reports on recent progress and advances in the catalytic valorization of cellulose, hemicellulose and lignin model molecules promoted by novel heterogeneous systems for the production of energy, fuels and chemicals.
Book Synopsis Bimetallic Catalysis in Hydrodeoxygenation of Lignin Derived Molecules by : Yongchun Hong
Download or read book Bimetallic Catalysis in Hydrodeoxygenation of Lignin Derived Molecules written by Yongchun Hong and published by . This book was released on 2016 with total page 211 pages. Available in PDF, EPUB and Kindle. Book excerpt: Hydrodeoxygenation (HDO) of phenolic compounds is an important model reaction in understanding the fundamental and application of catalysis in lignin based biofuel production. Recently, Fe has emerged as a promising catalyst for HDO of phenolics, due to its low cost and high selectivity in C-O bond cleavage. However, Fe's low HDO activity and poor stability under HDO conditions has limited its application. In this work, we developed an efficient approach to promote Fe's activity and stability without altering its unique selectivity in HDO of phenolics, by doping noble metals such as Pd onto Fe catalyst surface. A series of noble metal doped Fe catalysts were tested in HDO of m-cresol. Noble metals remarkably promoted Fe's activity and stability, while maintaining Fe's high C-O bond cleavage selectivity. To better understand this synergistic catalysis, a systematic study using both experimental and theoretical tools such as reaction kinetics, electron microscopy, in situ spectroscopies and DFT calculation was performed. The Pd-on-Fe nanostructure with sub-nm Pd clusters on reduced Fe surface in Pd-Fe catalyst was evidenced by high resolution STEM and pseudo in situ XPS. A direct C-O bond cleavage mechanism, in which m-cresol decomposes on Fe surface into C7H7* and OH* species and the formed species further reacts with H atoms to form toluene and water, respectively, was proposed based on DFT calculation and kinetic modeling. Kinetic modeling and in situ AP-XPS results suggested that Fe catalyst surface is dominated by OH* species, which ultimately lead to a deactivation of Fe catalyst. Addition of Pd to Fe significantly changes its kinetics by creating new sites for H2 activation and new reaction pathways via reaction between H activated on Pd sites and C 7H7* and OH* on Fe sites, as suggested by kinetic modeling. As a result, the surface of Pd-Fe is no longer dominated by OH* and catalyst deactivation by water induced oxidation is thus avoided. The concept of constructing Pd-on-Fe type nanostructure to stabilize base metal catalysts and at the same time promote their activity without altering their unique selectivity is potentially of border impact in other heterogeneous catalysis applications.
Book Synopsis Catalytic Hydrodeoxygenation of Lignin Model Compounds by : Stephen John Hurff
Download or read book Catalytic Hydrodeoxygenation of Lignin Model Compounds written by Stephen John Hurff and published by . This book was released on 1982 with total page 270 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Hydrotreatment of Lignin Into Green Fuels and Chemicals by : Matthew Alexander Tymchyshyn
Download or read book Hydrotreatment of Lignin Into Green Fuels and Chemicals written by Matthew Alexander Tymchyshyn and published by . This book was released on 2015 with total page 412 pages. Available in PDF, EPUB and Kindle. Book excerpt: Concerns about declining non-renewable fossil resources, energy security, climate change and sustainability are increasing worldwide. This has resulted in an increased interest in the development of alternatives to fossil resources not only for energy, but particularly for chemical production on a global level. There are a number of promising alternatives to fossil resources, however, lignocellulosic biomass such as forestry residues and wood waste (bark, sawdust, etc.) seem to be the most promising. They are widely available, renewable and a non-food resource. Therefore woody biomass holds the promise of being a sustainable resource for both energy and chemical production. The lignin component of woody biomass is of particular interest as it comprises the world's largest natural source of aromatic compounds and is produced in large quantities as a byproduct of pulp and paper processing. The main challenge in lignin utilization for fuels and chemicals is that it is composed of very large molecules with low heating values (due to high oxygen content) and low reactivity. Accordingly, the overall objective of this work is the production of chemicals and fuels by the catalytic hydroprocessing of lignin and ligninderived bio-oils aiming to reduce their molecular weights and oxygen contents. This work investigated the catalytic hydrotreatment (hydroprocessing) of a number of different lignins as well as depolymerized hydrolysis lignin for the production of fuels and chemicals. Several supported metal hydrogenation catalysts were investigated for the depolymerization, deoxygenation and desulfurization of Kraft lignin (KL) organosolv lignin (OL) and hydrolysis lignin (HL) under hydrogen atmospheres to produce depolymerized lignins. All of the catalysts tested were effective in depolymerizing the lignin feedstocks, however, the alumina- supported catalysts and the carbon-supported Ni catalyst did not perform as well as the carbon-supported Ru catalyst and FHUDS-2 (an industrial HDS catalyst). The molecular weights of the depolymerized lignins using these last two catalysts at 300 °C were markedly lower than the OL and KL feeds (1̃,000 vs. 2,600 and 10,200 g/mol, respectively). In addition, the sulfur contents of the depolymerized Kraft lignins were drastically reduced. Targeting the development of effective and inexpensive catalysts for the hydrotreatment of lignin and lignin-derived bio-oils to produce chemicals and fuels, screening of catalysts was performed using guaiacol as model compound. The most effective catalyst under the conditions tested was found to be 1 wt.% Mo-doped 5 wt.% Ru supported on activated charcoal (MoRu/AC). The selected catalyst proved to be very effective for hydrotreatment of organosolv lignin (MW H"2,600 g/mol) into a liquid product comprising>85% phenolic compounds with a MW of 460 g/mol at 7̃0% yield at 340 °C. This catalyst was also successfully employed in the hydroprocessing of hydrolysis lignin (HL) and depolymerized hydrolysis lignin (DHL).
Book Synopsis Reductive Conversion of Lignin to Aromatic Chemicals with Earth Abundant Catalysts by : Eric Michael Anderson (Ph. D.)
Download or read book Reductive Conversion of Lignin to Aromatic Chemicals with Earth Abundant Catalysts written by Eric Michael Anderson (Ph. D.) and published by . This book was released on 2019 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt: The viability of lignocellulosic biomass as a feedstock for chemicals hinges on the successful utilization of the lignin. Lignin, which comprises 15-30 wt% of biomass, is an amorphous polymer composed of multiple phenolic monomers. Lignin polymerization occurs through an uncontrolled radical coupling of monomers leading to an array of C-O and C-C bonds in the polymer. As such, lignin is highly recalcitrant and is responsible for the poor utilization of biomass. Many harsh thermochemical processes exist to extract lignin, but typically result in the destruction and condensation of the lignin rendering it as process waste. Alternative fractionation techniques focused on preserving lignin have recently been developed. These methods utilize reduction catalysts to depolymerize and stabilize reactive lignin fragments to produce stable phenols. This work focuses on the design of flow reactors to understand this process, evaluate catalysts and elucidate how structural changes in biomass impact lignin depolymerization and upgrading. Our lignin conversion process operates by adding a heterogeneous reduction catalyst with whole biomass, a solvent and a reducing agent. Two key steps were discovered in the reductive conversion of lignin. First, lignin oligomers are liberated from the biomass by solvolytic cleavage of lignin-carbohydrate bonds. Next, lignin oligomers are reductively fragmented at the catalyst surface to produce stable phenolic compounds. Lignin solvolysis and reduction were physically separated in a dual-bed flow-through reactor, which allows for independent control of each step. Direct control of lignin solvolysis and reduction allowed for limiting conditions to be isolated. Reduction limited conditions were used to study catalyst activity and stability. Solvolysis limiting conditions were used to probe how lignin structure influences product selectivity and yield. Additionally, molybdenum-based catalysts were developed for the conversion of lignin-derived phenols into aromatics. Gas phase reactions with n-propyl guaiacol demonstrated that molybdenum polyoxometalates are effective catalysts to perform simultaneous alkylationhydrodeoxygenation to produce alkylated aromatics from phenolics. Finally, the dual-bed reactor was used to combine reductive fractionation and deoxygenation chemistry to directly convert lignin into aromatics over a molybdenum carbide catalyst. Overall, a versatile reactor system was developed to facilitate fundamental studies to understand biomass structure and catalyst performance.
Book Synopsis Catalytic Hydrogenation of Coal-derived Liquids and Related Polycyclic Aromatic and Heterocyclic Compounds by : Lavanga Reddiar Veluswamy
Download or read book Catalytic Hydrogenation of Coal-derived Liquids and Related Polycyclic Aromatic and Heterocyclic Compounds written by Lavanga Reddiar Veluswamy and published by . This book was released on 1977 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Lignocellulose Valorization: Fractionation, Conversion and Applications by : Xiaojun Shen
Download or read book Lignocellulose Valorization: Fractionation, Conversion and Applications written by Xiaojun Shen and published by Frontiers Media SA. This book was released on 2022-08-22 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Catalytic Depolymerization Of Switchgrass-Derived Lignin From Optimized Cosolvent Enhanced Lignocellulosic Fractionation Process To Produce Aromatics And Sustainability Assessment Of Lignin Using Life Cycle Assessment by : James Godwin
Download or read book Catalytic Depolymerization Of Switchgrass-Derived Lignin From Optimized Cosolvent Enhanced Lignocellulosic Fractionation Process To Produce Aromatics And Sustainability Assessment Of Lignin Using Life Cycle Assessment written by James Godwin and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: As we continue to witness the devastating impact of climate change, there have been renewed calls from industrial stakeholders and government policy makers on the need to accelerate the pace of development of renewable materials and a shift towards renewable forms of energy. This would reduce dependence on fossil-based products, which have been considered a major contributor to global warming. Lignin has garnered attention in recent times due to its availability as the second most abundant polymer on earth, and the potential it holds which is still yet to be fully tapped. In this work, the goal was to develop a sustainable process that can be used to extract and depolymerize lignin from switchgrass. The main objectives were to first isolate lignin from switchgrass and synthesize metal catalysts which can be used to modify the lignin structure whilst generating valuable aromatic compounds for downstream biorefining; second, to optimize the lignin isolation process to obtain a lignin with distinct structural features that make it suitable for polymer-based application using 3D printing technology; third, to access the carbon footprint of the lignin isolation process to determine its environmental performance. First, lignin was isolated from switchgrass using cosolvent enhanced lignocellulosic fractionation (CELF) and depolymerized using synthesized spinel-type mixed-metal oxide catalyst (NiCo2O4) made from earth-abundant transition metals. Catalytic transfer hydrogenolysis reaction was used to depolymerize the lignin to tune the oxidation state at the C[alpha]. Results of catalyst activity with acetophenone as model compound showed a 75 % conversion and ~90 % selectivity for ethyl benzene. The catalyst was then used for lignin reaction, yielding a suit of aromatic compounds in the process, which were identified and semi-quantitatively analyzed using gas chromatography/mass spectrometry (GC/MS) and structural analysis was performed using two-dimension nuclear magnetic resonance (2D-NMR) spectroscopic technique. The CELF process was them optimized using Response Surface Methodology (RSM) and Box-Behnken design with targeted response variables of yield, molecular weight (Mw) and hydroxyl group (OH) content using temperature (140 -- 180 °C), acid concentration (0.025 -- 0.1 M), and time (10 -- 30 mins) as predictors. The optimal point that maximizes yield, minimizes Mw, and maximizes OH group content, was achieved and validated at 169 °C, 0.1 M and 10 mins respectively. A life cycle assessment (LCA) was conducted using OpenLCA software, with a functional unit (F.U) of 1 kg of CELF-derived lignin from switchgrass using a cradle-to-gate approach. The system boundary was limited to contain only the switchgrass cultivation, CELF fractionation, Solvent recovery, washing, and vacuum drying. Transportation from switchgrass cultivation site to processing site was assumed to be 50 km, tetrahydrofuran (THF) and water were used as primary cosolvents, and the switchgrass had a yield of 9 Mg/ha with a 15 % moisture at harvest. The material flow was modeled using SuperPro Designer to determine the mass balance for the process, with secondary data obtained from ecoinvent 2016 and primary data from some laboratory experimentation and the farm energy analysis tool (FEAT) model. ReCipe midpoint (H) V1.13 was used as impact assessment method to quantify the associated impact categories from production of lignin. A sensitivity analysis was also performed to determine which of the parameters were most sensitive to the overall impact of the process; for this study, solvent type was the only parameter tested due to time constraints. Results showed that the overall impact was highly sensitive to solvent type resulting in a GWP reduction of ~73 % in the base case scenario when THF was substituted with methanol; and in the alternate case with 70 % and 90 % recycling of solvent. The result showed a GWP of 6 kg CO2eq. The result in the best-case scenario indicated a higher GWP than previous studies on kraft lignin. However, the biogenic carbon content of lignin was not accounted for in this study, which some previous studies had incorporated into the overall GWP to offset CO2 emissions from the process. This study presents useful data for biorefinery stakeholders exploring CELF process for high purity lignin production.
Download or read book Converting Lignin to Aromatics written by and published by . This book was released on 2014 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Lignin, the glue that holds trees together, is the most abundant natural resource of aromatics. In that respect, it is a far more advanced resource than crude oil. This is because lignin already contains the aromatic functional groups. Thus, catalytic conversion of lignin to high-value aromatics is environmentally attractive, but can also be an economically viable option. The aim of this PhD thesis is to understand the fundamentals of lignin depolymerization reactions through the study of monomeric and dimeric model compounds and then move towards the actual lignin as feedstock. The development and improvement of selective catalytic reactions, such as hydrodeoxygenation, are fundamental to enhance the catalytic valorisation of lignin towards high value aromatics. Therefore, we focused on the study of model compounds that can mimic lignin linkages to find a catalytic alternative that can cleave selectively these bonds and then hydrodeoxygenate the smaller fractions obtained to target molecules such as phenol and BTX. Actual lignin was also used for a solubilisation and fractionation study using an unconventional solvent, liquid ammonia. The main reactions envisaged are demethylation and hydrodeoxygenation leading to aromatic building blocks such as benzene, toluene and xylene (BTX) and phenol using heterogeneous catalysts."--Samenvatting auteur.
