Heat of reaction of hydrothermal liquefaction reactions

Wet waste streams include a wide variety of products such as food processing residues, sewage sludge but also the organic fraction of municipal solid waste. Humidity typically varies from 50 to above 90 %. Dewatering and drying is possible for most feedstocks but at a significant cost. Hydrothermal liquefaction produces a biocrude that can be further upgraded into biofuels. The conversion takes place at temperatures between 250 and 400 °C and at pressures above the saturation pressure to ensure that water remains in the liquid phase, typically above 100 bar [1]. Even though the basic principles of hydrothermal liquefaction are well known, there are still some significant scientific questions and technical issues. One of the important questions that remain is the heat of reaction and the heat balance of the reaction. Please click Additional Files below to see the full abstract

Hydrothermal liquefaction process of food waste in batch and continuous lab scale reactors

Due to the energy burden that represents the drying step, wet biomass is often underexploited for energy purpose. Indeed, this step represents one of the most energy consuming step in a thermochemical process and is often economically prohibitive. During hydrothermal liquefaction, conversion of biomass takes place at temperatures between 250 and 374 °C and at pressures above the saturation pressure to ensure that water remains in the liquid phase, typically above 100 bars, avoiding enthalpy energy penalties [1]. To avoid competitive use of land for food supply and excessive cost of entrance biomass, blackcurrant pomace and brewery’s spent grains have been selected and tested on liquefaction as food residues. Experiments have been carried out in a 600 mL batch reactor (PARR), allowing maximum temperature of 320°C and maximum pressure of 130 bars. Effects of operating parameters such as temperature and holding time, biomass pretreatment and reactor configuration are investigated on mass yields, aqueous phase composition and energy balance. Results obtained in the batch reactor constitute the reference of this study, in the comprehension of the mechanism of the liquefaction of food residues. Also, these results form the basis for a model to scale up the process, and are confronted to the results on a continuous lab scale plant. Please click Additional Files below to see the full abstract

Une histoire d'impressions : le Québec au XXe siècle : œuvres sur papier de la collection de l'Université de Montréal : 10 avril au 14 juin 2019 : catalogue d'exposition en ligne

Catalogue préparé sous la direction de Christine Bernier.Catalogue d'une exposition tenue au Carrefour des arts et des sciences de l’Université de Montréal, du 10 avril au 14 juin 2019. Commissariat général de l’exposition réalisée par des étudiants de 2e cycle à l'hiver 2019 dans le cadre du cours HAR 6080 / MSL 6509 : Muséologie et histoire de l'art, donné par la professeure Christine Bernier.Artistes dont les œuvres ont été exposées : Cozic, Louis Comtois, Roland Giguère, Denis Juneau, Peter Krausz, Michel Leclair, Norman McLaren, Moe Reinblatt, Francine Simonin, Serge Tousignant

Conception et évaluation d’un procédé de liquéfaction hydrothermale en vue de la valorisation énergétique de résidus agroalimentaires

Face to climatic emergency, new carbon-neutral and renewable ways to produce energy have to be developed. Biomass appears as a promising alternative to produce an energetic carrier to meet the challenges of a sustainable development. Food industrial waste is a stable source of biomass in time. However, it is often valorised through low-cost applications due to their high-water content. This work investigates the production of a biofuel from this waste through the hydrothermal liquefaction process. This technology allows the conversion of biomass under temperature [250 °C – 350 °C] in a liquid medium, kept under pressure. Despite the fact hydrothermal liquefaction is known for a while, the lack of commercial outlet, due to petroleum fuels competitiveness, technological and scientific issues have slowed down its development. Few continuous plants exist and most of studies have been conducted in batch reactors. This work aims to assess the potential of the scaling up of hydrothermal liquefaction for energetic valorisation of food industrial residues. Experiments have been carried out on blackcurrant pomace (BCP) and brewers’ spent grains (BSG). First, batch experiments have shown the respective potential of these residues for biofuel production. Biocrude obtained is a mix of a heavy solid fraction called biochar and a lighter phase, the biooil. Their respective yields depends on processing conditions. About 33 % and 24 % of boioil can be expected for respectively BCP (300 °C) and BSG (315 °C), with 15 minutes reaction time. Biocrudes present a higher heating value close to 33 MJ/kg, but also high concentrations of heteroatoms and biochar. Upgrading steps are then necessary before valorisation in liquid biofuel. Based on these observations, a predictive model has been developed as a sum of parallel and serial reactions, with different kinetics. Almost 70 % of the experimental results have been predicted in a 10 % confidence interval from the composition of biomasses, temperature and reaction time. Confrontation with literature and statistical analysis reveal that some additional work is needed to improve and clarify some reactional pathways. Inspired from works on hydrothermal carbonisation, methods have been developed to estimate the enthalpy of reaction. Results show that hydrothermal liquefaction of food industrial residues is overall exothermal. Enthalpies have been estimated between -3,0 et -1,2 MJ/kg for BCP and between -1,97 et -0,9 MJ/kg for BSG. Although technical changes are still necessary, pilot has been adapted to ensure long time runs. These experiments have validated the calculation of the enthalpy of reaction obtained from the batch reactor. However, results from continuous experiments indicate that less biochar is formed for more gaseous and aqueous products. All the energy and mass balances established from experimental work have been integrated in simulation flowsheet in PROSIMPLUS®. A technico-economic evaluation based on this simulation returns a minimum selling price for biocrude. With economic assumptions, minimum prices calculated are 2,28 et 2,97 €/L for biocrude from BCP and BSG. Prices are still high in comparison with crude. The impact of variations of the installation capacity, initial capital cost, biocrude yields and gate fee has been estimated on final biocrude price. By considering higher capacities, it seems possible to reduce significantly biocrude selling price.L’urgence climatique impose aujourd’hui de développer de nouveaux vecteurs énergétiques, à partir de ressources renouvelables et neutre en carbone. Les résidus agroalimentaires constituent une source de biomasse stable dans le temps. Cependant, en raison de leur humidité importante, ils sont souvent valorisés en produit à faible valeur ajoutée. On s’est ici intéressé à la production d’un carburant, à partir de résidus agroalimentaires par le procédé de liquéfaction hydrothermale. Cette technologie permet la conversion de la biomasse sous l’effet de la température [250 °C – 350 °C] dans une eau pressurisée et gardée liquide. Bien que le procédé soit connu, son développement est freiné par manque d’applications commerciales en raison de la compétitivité des ressources pétrolières, des difficultés technologiques et scientifiques. Peu de pilotes continus existent et les principaux résultats proviennent d’études principalement réalisées en batch. Ce travail étudie le potentiel du passage à l’échelle du procédé de liquéfaction hydrothermale pour la valorisation énergétique de résidus agroalimentaires. Les essais ont été réalisés sur des drêches de cassis (DC) et des drêches de brasserie (DB). Une première étude réalisée sur un pilote batch a permis de mettre en évidence le potentiel des résidus agroalimentaires pour la production de biocrude, mélange d’une fraction solide appelée biochar et une fraction légère la biohuile dont les rendements dépendent des conditions opératoires. On peut ainsi espérer jusqu’à 33 % de biohuile à partir des DC (300 °C) et 24 % à partir des DB (315 °C) pour 15 minutes de temps de palier. Les biocrudes obtenus présentent un pouvoir calorifique proche de 33 MJ/kg et des concentrations en hétéroatomes et biochar élevées. Des étapes de raffinage sont à envisager avant toute valorisation sous forme de carburant. Sur la base de ces résultats, Un modèle prédictif a été construit comme un ensemble de réactions en parallèle et en série, aux cinétiques différentes. Le modèle permet de prédire environ 70 % des résultats expérimentaux dans un intervalle de confiance de 10 % à partir de la composition des biomasses, de la température et du temps de réaction. L’analyse statistique menée sur les coefficients ainsi que la comparaison avec la littérature a permis d’identifier certains chemins réactionnels à retravailler. Des méthodes inspirées des travaux menées de carbonisation hydrothermale ont été développées et ont permis d’observer que la liquéfaction des résidus agroalimentaires était exothermique, avec des enthalpies de réaction estimées entre -3,0 et -1,2 MJ/kg pour les DC et -1,97 et -0,9 MJ/kg pour les DB. Les difficultés techniques ont conduit à adapter le pilote de liquéfaction continu, cependant des essais longue durée ont pu valider le calcul des enthalpies de réaction obtenues sur le batch, validant à l’échelle du pilote la possibilité de réaliser des économies d’énergie. En comparaison avec les rendements obtenus sur le batch, le passage en continu évite la formation de biochar au profit d’une solubilisation accrue de la matière, et de la production de gaz. Enfin, les données expérimentales ont été intégrées dans un outil de simulation (PROSIMPLUS®) et ont servi de base à une évaluation technico économique permettant d’estimer le prix minimum de vente du biocrude. Selon les hypothèses économiques retenues, les prix de vente sont respectivement de 2,28 et 2,97 €/L pour les biocrudes issus des DC et des DB. Ces prix restent élevés en comparaison avec celui du pétrole. La sensibilité de ces prix a été estimée en fonction de la taille de l’installation, du coût initial investi, des rendements en biocrude ainsi que du coût de traitement des résidus (gate fee). Il doit cependant être possible de diminuer le coût du biocrude en considérant des tailles d’installation plus grande

Evaluation of the Heat Produced by the Hydrothermal Liquefaction of Wet Food Processing Residues and Model Compounds

Hydrothermal liquefaction has proven itself as a promising pathway to the valorisation of low-value wet food residues. The chemistry is complex and many questions remain about the underlying mechanism of the transformation. Little is known about the heat of reaction, or even the thermal effects, of the hydrothermal liquefaction of real biomass and its constituents. This paper explores different methods to evaluate the heat released during the liquefaction of blackcurrant pomace and brewers’ spent grains. Some model compounds have also been evaluated, such as lignin, cellulose and glutamic acid. Exothermic behaviour was observed for blackcurrant pomace and brewers’ spent grains. Results obtained in a continuous reactor are similar to those obtained in a batch reactor. The heat release has been estimated between 1 MJ/kg and 3 MJ/kg for blackcurrant pomace and brewers’ spent grains, respectively. Liquefaction of cellulose and glucose also exhibit exothermic behaviour, while the transformation of lignin and glutamic acid present a slightly endothermic behaviour

Design and evaluation of a hydrothermal liquefaction process for the energy recovery of agro-food residues

L’urgence climatique impose aujourd’hui de développer de nouveaux vecteurs énergétiques, à partir de ressources renouvelables et neutre en carbone. Les résidus agroalimentaires constituent une source de biomasse stable dans le temps. Cependant, en raison de leur humidité importante, ils sont souvent valorisés en produit à faible valeur ajoutée. On s’est ici intéressé à la production d’un carburant, à partir de résidus agroalimentaires par le procédé de liquéfaction hydrothermale. Cette technologie permet la conversion de la biomasse sous l’effet de la température [250 °C – 350 °C] dans une eau pressurisée et gardée liquide. Bien que le procédé soit connu, son développement est freiné par manque d’applications commerciales en raison de la compétitivité des ressources pétrolières, des difficultés technologiques et scientifiques. Peu de pilotes continus existent et les principaux résultats proviennent d’études principalement réalisées en batch. Ce travail étudie le potentiel du passage à l’échelle du procédé de liquéfaction hydrothermale pour la valorisation énergétique de résidus agroalimentaires. Les essais ont été réalisés sur des drêches de cassis (DC) et des drêches de brasserie (DB). Une première étude réalisée sur un pilote batch a permis de mettre en évidence le potentiel des résidus agroalimentaires pour la production de biocrude, mélange d’une fraction solide appelée biochar et une fraction légère la biohuile dont les rendements dépendent des conditions opératoires. On peut ainsi espérer jusqu’à 33 % de biohuile à partir des DC (300 °C) et 24 % à partir des DB (315 °C) pour 15 minutes de temps de palier. Les biocrudes obtenus présentent un pouvoir calorifique proche de 33 MJ/kg et des concentrations en hétéroatomes et biochar élevées. Des étapes de raffinage sont à envisager avant toute valorisation sous forme de carburant. Sur la base de ces résultats, Un modèle prédictif a été construit comme un ensemble de réactions en parallèle et en série, aux cinétiques différentes. Le modèle permet de prédire environ 70 % des résultats expérimentaux dans un intervalle de confiance de 10 % à partir de la composition des biomasses, de la température et du temps de réaction. L’analyse statistique menée sur les coefficients ainsi que la comparaison avec la littérature a permis d’identifier certains chemins réactionnels à retravailler. Des méthodes inspirées des travaux menées de carbonisation hydrothermale ont été développées et ont permis d’observer que la liquéfaction des résidus agroalimentaires était exothermique, avec des enthalpies de réaction estimées entre -3,0 et -1,2 MJ/kg pour les DC et -1,97 et -0,9 MJ/kg pour les DB. Les difficultés techniques ont conduit à adapter le pilote de liquéfaction continu, cependant des essais longue durée ont pu valider le calcul des enthalpies de réaction obtenues sur le batch, validant à l’échelle du pilote la possibilité de réaliser des économies d’énergie. En comparaison avec les rendements obtenus sur le batch, le passage en continu évite la formation de biochar au profit d’une solubilisation accrue de la matière, et de la production de gaz. Enfin, les données expérimentales ont été intégrées dans un outil de simulation (PROSIMPLUS®) et ont servi de base à une évaluation technico économique permettant d’estimer le prix minimum de vente du biocrude. Selon les hypothèses économiques retenues, les prix de vente sont respectivement de 2,28 et 2,97 €/L pour les biocrudes issus des DC et des DB. Ces prix restent élevés en comparaison avec celui du pétrole. La sensibilité de ces prix a été estimée en fonction de la taille de l’installation, du coût initial investi, des rendements en biocrude ainsi que du coût de traitement des résidus (gate fee). Il doit cependant être possible de diminuer le coût du biocrude en considérant des tailles d’installation plus grande.Face to climatic emergency, new carbon-neutral and renewable ways to produce energy have to be developed. Biomass appears as a promising alternative to produce an energetic carrier to meet the challenges of a sustainable development. Food industrial waste is a stable source of biomass in time. However, it is often valorised through low-cost applications due to their high-water content. This work investigates the production of a biofuel from this waste through the hydrothermal liquefaction process. This technology allows the conversion of biomass under temperature [250 °C – 350 °C] in a liquid medium, kept under pressure. Despite the fact hydrothermal liquefaction is known for a while, the lack of commercial outlet, due to petroleum fuels competitiveness, technological and scientific issues have slowed down its development. Few continuous plants exist and most of studies have been conducted in batch reactors. This work aims to assess the potential of the scaling up of hydrothermal liquefaction for energetic valorisation of food industrial residues. Experiments have been carried out on blackcurrant pomace (BCP) and brewers’ spent grains (BSG). First, batch experiments have shown the respective potential of these residues for biofuel production. Biocrude obtained is a mix of a heavy solid fraction called biochar and a lighter phase, the biooil. Their respective yields depends on processing conditions. About 33 % and 24 % of boioil can be expected for respectively BCP (300 °C) and BSG (315 °C), with 15 minutes reaction time. Biocrudes present a higher heating value close to 33 MJ/kg, but also high concentrations of heteroatoms and biochar. Upgrading steps are then necessary before valorisation in liquid biofuel. Based on these observations, a predictive model has been developed as a sum of parallel and serial reactions, with different kinetics. Almost 70 % of the experimental results have been predicted in a 10 % confidence interval from the composition of biomasses, temperature and reaction time. Confrontation with literature and statistical analysis reveal that some additional work is needed to improve and clarify some reactional pathways. Inspired from works on hydrothermal carbonisation, methods have been developed to estimate the enthalpy of reaction. Results show that hydrothermal liquefaction of food industrial residues is overall exothermal. Enthalpies have been estimated between -3,0 et -1,2 MJ/kg for BCP and between -1,97 et -0,9 MJ/kg for BSG. Although technical changes are still necessary, pilot has been adapted to ensure long time runs. These experiments have validated the calculation of the enthalpy of reaction obtained from the batch reactor. However, results from continuous experiments indicate that less biochar is formed for more gaseous and aqueous products. All the energy and mass balances established from experimental work have been integrated in simulation flowsheet in PROSIMPLUS®. A technico-economic evaluation based on this simulation returns a minimum selling price for biocrude. With economic assumptions, minimum prices calculated are 2,28 et 2,97 €/L for biocrude from BCP and BSG. Prices are still high in comparison with crude. The impact of variations of the installation capacity, initial capital cost, biocrude yields and gate fee has been estimated on final biocrude price. By considering higher capacities, it seems possible to reduce significantly biocrude selling price

Kinetic Modelling for Hydrothermal Conversion of Food Wastes

A kinetic model was developed for the prediction of HTL product yields based on a chemical mechanism. The model was developed after experimental studies on food wastes and food processing wastes. The model parameters were determined by training the model on experimental data on HTL of food wastes. Two other models from the literature were also tested. The calculated yields were compared with a large range of experimental data from the literature. Yields of bio-oil and char can be predicted from the process conditions, temperature, holding time, dry matter content, and the biochemical composition of the resource. Differences in the experimental recovery procedure and polarity of the extraction solvent are taken into account. This study shows that a kinetic model based on compositions allows a more detailed representation of the hydrothermal reactions than models purely based on resources and products. The precision of any model remains, however, largely dependent on the quality of the input data

Development of a kinetic model for HTL conversion of waste biomass

International audienceThe objective of this work is to develop a simulation tool in order to predict the HTL product distribution in term of aqueous phase, gas phase, bio-oil and bio-char for an organic waste based on it biochemical composition and the conversion conditions (temperature and residence time). A reaction scheme was proposed after compositional analysis of the resources and the reaction products. The kinetic parameter of this mechanism were optimized by minimizing the differences with the experimental yields of gas, aqueous phase, bio-oil and bio-char for 24 experimental points. Each point was produced from 2 to 4 experiments.The model is able to reproduce the evolution of the different product fraction with time except at the beginning between 0 and 20 min this is during the heat up time were the temperature is always changing leading to a non-stationery situation. This tool can be used for a process simulation in the prediction of product yields and. To obtain a more precise model, a work is ongoing in the laboratory with quantification of intermediate species in an objective of developing a comprehensive and predictive model of intermediate species or intermediate family of species.

Evaluation of the Heat Produced by the Hydrothermal Liquefaction of Wet Food Processing Residues and Model Compounds

Hydrothermal liquefaction has proven itself as a promising pathway to the valorisation of low-value wet food residues. The chemistry is complex and many questions remain about the underlying mechanism of the transformation. Little is known about the heat of reaction, or even the thermal effects, of the hydrothermal liquefaction of real biomass and its constituents. This paper explores different methods to evaluate the heat released during the liquefaction of blackcurrant pomace and brewers’ spent grains. Some model compounds have also been evaluated, such as lignin, cellulose and glutamic acid. Exothermic behaviour was observed for blackcurrant pomace and brewers’ spent grains. Results obtained in a continuous reactor are similar to those obtained in a batch reactor. The heat release has been estimated between 1 MJ/kg and 3 MJ/kg for blackcurrant pomace and brewers’ spent grains, respectively. Liquefaction of cellulose and glucose also exhibit exothermic behaviour, while the transformation of lignin and glutamic acid present a slightly endothermic behaviour

Development of a kinetic model for HTL conversion of waste biomass

International audienceThe objective of this work is to develop a simulation tool in order to predict the HTL product distribution in term of aqueous phase, gas phase, bio-oil and bio-char for an organic waste based on it biochemical composition and the conversion conditions (temperature and residence time). A reaction scheme was proposed after compositional analysis of the resources and the reaction products. The kinetic parameter of this mechanism were optimized by minimizing the differences with the experimental yields of gas, aqueous phase, bio-oil and bio-char for 24 experimental points. Each point was produced from 2 to 4 experiments.The model is able to reproduce the evolution of the different product fraction with time except at the beginning between 0 and 20 min this is during the heat up time were the temperature is always changing leading to a non-stationery situation. This tool can be used for a process simulation in the prediction of product yields and. To obtain a more precise model, a work is ongoing in the laboratory with quantification of intermediate species in an objective of developing a comprehensive and predictive model of intermediate species or intermediate family of species.