Dra. Tamara Llano Astuy | Universidad de Cantabria (original) (raw)
Papers by Dra. Tamara Llano Astuy
ABSTRACT: Physico-chemical and biological processes can be used to transform different pulp and p... more ABSTRACT: Physico-chemical and biological processes can be used to transform different pulp and paper industries through integrated forest biorefineries in order to valorise all of the main fractions of the lignocellulosic biomass (cellulose, hemicellulose and lignin). In this work, hydrolysis and fractionation processes have been studied in a sulphite pulp mill to obtain not only dissolving pulp from the cellulose but also lignosulphonates from the lignin and fermentation products from the hemicellulose. Delignification and hydrolysis experiments have been carried out at laboratory scale in order to increase the valorization opportunities and trying to decrease the inhibitors in the final by-product. In addition, detoxification or separation treatments have been developed in order to separate the lignosulphonates and other inhibitors from the sugar substrate.RESUMEN:Diferentes procesos físico-químico y biológicos se pueden utilizar para transformar la industria de la pasta y celulo...
VII Simposio Iberoamericano #R##N#en Ingeniería de Residuos : #R##N#Hacia una economía circular, Santander, Universidad de Cantabria, 2017, 2017
RESUMEN: Es bien sabido que durante la producción de pasta dissolving de alta pureza, se genera u... more RESUMEN: Es bien sabido que durante la producción de pasta dissolving de alta pureza, se genera un residuo denominado licor gastado de cocción altamente rico en azúcares. Este hecho, convierte la industria del pasteado en potenciales biorrefinerías lignocelulósicas por medio de la integración de algunas modificaciones en el proceso actual. Esta tesis contribuye a la transformación de una industria de pasta al sulfito ácido localizada en la región de Cantabria (España) en una moderna biorrefinería forestal. En primer lugar se estudiaron los procesos de digestión y blanqueo. Posteriormente, el residuo principal (licor gastado al sulfito) fue caracterizado, externamente hidrolizado y detoxificado para intensificar el rendimiento y la productividad de la fermentación del mismo. La transformación propuesta preserva las propiedades de calidad de la pasta, logrando mejoras en la conversión de los azúcares y en la separación de otros subproductos para su posterior valorización.ABSTRACT: It ...
VII Simposio Iberoamericano #R##N#en Ingeniería de Residuos : #R##N#Hacia una economía circular, Santander, Universidad de Cantabria, 2017, 2017
Materials, 2016
The complete bioconversion of the carbohydrate fraction is of great importance for a lignocellulo... more The complete bioconversion of the carbohydrate fraction is of great importance for a lignocellulosic-based biorefinery. However, due to the structure of the lignocellulosic materials, and depending basically on the main parameters within the pretreatment steps, numerous byproducts are generated and they act as inhibitors in the fermentation operations. In this sense, the impact of inhibitory compounds derived from lignocellulosic materials is one of the major challenges for a sustainable biomass-to-biofuel and-bioproduct industry. In order to minimise the negative effects of these compounds, numerous methodologies have been tested including physical, chemical, and biological processes. The main physical and chemical treatments have been studied in this work in relation to the lignocellulosic material and the inhibitor in order to point out the best mechanisms for fermenting purposes. In addition, special attention has been made in the case of lignocellulosic hydrolysates obtained by chemical processes with SO 2 , due to the complex matrix of these materials and the increase in these methodologies in future biorefinery markets. Recommendations of different detoxification methods have been given.
Biomass and Bioenergy, 2021
The transformation of fermentable sugars provided from lignocellulosic wastes into biofuels or bi... more The transformation of fermentable sugars provided from lignocellulosic wastes into biofuels or bioproducts is a key point at second-generation biorefineries. Spent sulfite liquor is a xylose-rich hydrolysate constituting the main residue of sulfite mills producing dissolving cellulose. Due to the presence of the inhibitors in the spent liquor, the most promising valorization options require detoxification before sugars bioconversion. In this work, a multi criteria analysis was implemented to select techno-economic and socio-environmental feasible detoxification alternatives that can be adapted to a wide variety of fermenting scenarios. Total inhibitors removal, phenolics removal, acetic acid removal, lignosulfonates removal, total sugar losses, fixed capital invested, manufacturing costs, waste toxicity, social acceptance, and employment were chosen as the most relevant criteria. The maximum allowable concentration of undesirable inhibitors cannot be established with a general character, and thereby decision-making tools result in feasible and efficient solutions. From a technical viewpoint best solution was anionic resins with a score of 0.68; the most economical alternative was the overliming with a score of 0.76; finally, from a socio-environmental perspective, overliming reached the highest score of 0.78. In addition, three spent liquor biorefinery models were proposed. Based on the multicriteria analysis and based on the inhibitor's concentration affecting fermentation yields and productivity, the best detoxification alternatives were (1) anionic resins for polyhydroxyalkanoate production; (2) activated carbon for ethanol biorefinery; (3) overliming for xylitol biorefinery.
Sustainability
Solidification/stabilization (S/S) of acid waste using Ordinary Portland Cement (OPC) is widely i... more Solidification/stabilization (S/S) of acid waste using Ordinary Portland Cement (OPC) is widely implemented, but, due to the impact on climate change, alternative methods are being investigated. In this work, first, the feasibility of using coal fly-ash/clay-based geopolymers for the S/S of Zn plant residues (ZPR), Cadmium Sponge (CS), and Anode Mud (AM) is proposed as a treatment prior to disposal in landfills. Different variables, such as the type of processing, molding (as-received waste), and pressing (dried waste), and activators, a commercial and an alternative residual sodium carbonate, have been studied. The technical and environmental assessments of the S/S process by means of compressive strength and the leaching of critical pollutants have been monitored. Immobilization efficiencies of Cd and Zn higher than 99% have been obtained by dosing 50% of the acid waste, 6 M NaOH solution (20 min contact time), cured at 75 °C (48 h) and at room temperature (28 days), achieving in ...
Applied Sciences
The incorporation of coal fly ash (CFA) in fired clay bricks (FCBs), as a clay replacement, contr... more The incorporation of coal fly ash (CFA) in fired clay bricks (FCBs), as a clay replacement, contributes toward cleaner production practices. CFA disposal is an important issue worldwide due to its huge volume and to its potential negative environmental impacts, and currently does not have a recovery route due to its high concentration in unburned materials. In this study, the impact of the incorporation of two CFA, with different content of unburned carbon, FAA (low LOI) and FAB (high LOI) in FCBs, from a technical and environmental point of view was conducted. Unburned carbon plays an important role on the final properties of FCBs. The thermal decomposition during the firing process promotes an increase of water absorption, decreasing the flexural strength as the porosity increases, although the technical and mechanical properties of samples containing up to 30% FAA and percentages of 20% FAB are acceptable. The leaching behaviour showed an immobilisation of Cr and Se in FCBs while...
Cellulose, 2020
Choline chloride-based deep eutectic solvents are widely used in biomass processing. In this work... more Choline chloride-based deep eutectic solvents are widely used in biomass processing. In this work, four different green solvent mixtures were used as pre-treatment of acid sulphite dissolving pulp with the hypothesis of increasing the possibilities to produce viscose fibres and decreasing the use of the harmful and toxic carbon disulphide in the process. The experiments were performed at two different pulp to solvent mass ratios. Pulp quality parameters were also measured to determine the suitability of the pre-treatment: α-cellulose, viscosity, lignin and pentosan content. In addition, X-ray diffraction analysis of pulps at the best solid to liquid ratio was performed to obtain the influence of the crystallinity index. Best results were obtained with the use of lactic acid, with reactivity values close to 94%, giving a reduction of CS2 usage of 15.83%. Furthermore, a linear relationship between the crystallinity index calculated by the XRD and reactivity with a regression factor of 0.87 was found.
Journal of Chemical Technology & Biotechnology, 2021
Applied Sciences, 2021
The recent recovery processes of electric arc furnace dust (EAFD) include stabilization within ma... more The recent recovery processes of electric arc furnace dust (EAFD) include stabilization within materials with potential uses in the construction sector. The stabilization of EAFD by alkaline activation of different alumina-silicates, resulting in low-cost and environmentally friendly materials. The leaching standards within the different European regulations allow evaluating waste materials and products. This work aims to study the introduction of EAFD in FA–clay geopolymers, assessing the environmental and geochemical behavior in two different scenarios, disposal, and utilization. For it, the compliance equilibrium-based batch test (EN 12457-2) and pH dependence test (EN 14429) have been used. The dosages of EAFD in the geopolymeric matrix are 5% to 20% with curing temperatures of 75 °C and 225 °C. The introduction of EAFD favors the development of the flexural strength. From the environmental point of view, metals related to EAFD, such as Zn, Pb, or Cu, are retained in the matrix....
BioResources, 2018
A totally chlorine free (TCF) bleaching sequence was studied for an acid sulfite pulp mill that p... more A totally chlorine free (TCF) bleaching sequence was studied for an acid sulfite pulp mill that produces dissolving pulps. Laboratory analyses of the last two bleaching stages, an oxidant-reinforced alkaline extraction stage (EOP), and a subsequent pressurized peroxide with oxygen stage (PO), were performed on a eucalypt pulp that had been delignified by an ozone (Z) stage in the pulp mill. The goal was to predict the optimal costs and operational conditions for the (EOP)(PO) partial bleach sequence for three different specialty pulp products. Four independent variables affecting the pulp quality properties were examined for each stage (i.e., reaction temperature, reaction time, NaOH dosage and H2O2 dosage). The dependent variables were various pulp properties, such as intrinsic pulp viscosity, alpha-cellulose content, kappa number, and GE brightness. Three scenarios were considered to optimize the bleaching process, which related to a regenerated cellulose product (viscose) that is...
Waste and Biomass Valorization, 2015
This paper contains data related to the research paper entitled "Organic two-phase system based o... more This paper contains data related to the research paper entitled "Organic two-phase system based on acetonitrile þ water þ polyvinylpyrrolidone, a novel concept of liquid-liquid equilibrium: phase diagrams and phenolic compounds partitioning". Data of phase equilibrium were obtained using the cloud point method. After this step, some blending points were chosen to perform the phenolic compounds partitioning (gallic acid, quercetin dihydrate and cyanidin 3-O-glucoside chloride)
Journal of Chemistry, 2015
The evolution of lignin, five- and six-carbon sugars, and other decomposition products derived fr... more The evolution of lignin, five- and six-carbon sugars, and other decomposition products derived from hemicelluloses and cellulose was monitored in a sulfite pulp mill. The wastewater streams were characterized and the mass balances throughout digestion and total chlorine free bleaching stages were determined. Summative analysis in conjunction with pulp parameters highlights some process guidelines and valorization alternatives towards the transformation of the traditional factory into a lignocellulosic biorefinery. The results showed a good separation of cellulose (99.64%) during wood digestion, with 87.23% of hemicellulose and 98.47% lignin dissolved into the waste streams. The following steps should be carried out to increase the sugar content into the waste streams: (i) optimization of the digestion conditions increasing hemicellulose depolymerization; (ii) improvement of the ozonation and peroxide bleaching stages, avoiding deconstruction of the cellulose chains but maintaining i...
Carbohydrate Polymers, 2015
Spent sulfite liquor is a lignocellulosic waste obtained after the sulfite pulping process. It is... more Spent sulfite liquor is a lignocellulosic waste obtained after the sulfite pulping process. It is mainly formed by sugars and lignosulfonates which are isolated from the pulp during the cooking process. The current work investigates the kinetic modeling of the sulfite process from a biorefinery point of view since monosaccharides present in the spent liquor can be used as a raw material in further biorefinery processes to produce other value-added products. Kinetic parameters of carbohydrate degradation have been determined following sugar and inhibitors from wood to spent liquor, using laboratory scale reactors and different temperatures, 130, 140 and 150 °C. Three types of reaction schemes were developed. Kinetic parameters were obtained for each one using first and n order reactions, using Aspen Custom Modeler. Results show that the best temperature to be used in the process is 130 °C, giving the maximum sugar conversion, 33.91 mol% and obtaining 13.81 mol% of decomposition products.
Journal of Biotechnology, 2012
Biotechnology Reports, 2017
Waste from pulp and paper mills consist of sugar-rich fractions comprising hemicellulose derivati... more Waste from pulp and paper mills consist of sugar-rich fractions comprising hemicellulose derivatives and cellulose by-products. A complete characterisation of the waste streams is necessary to study the possibilities of an existing mill. In this work, four chromatographic methods have been developed to obtain the most suitable chromatographic method conditions for measuring woody feedstocks, lignocellulosic hydrolysates and cellulose pulp in sulphite pulping processes. The analysis of major and minor monosaccharides, aliphatic carboxylic acids and furfurals has been optimised. An important drawback of the spent liquors generated after sulphite pulping is their acidic nature, high viscosity and adhesive properties that interfere in the column lifetime. This work recommends both a CHO-782Pb column for the sugar analysis and an SH-1011 resin-based cross-linked gel column to separate lowmolecular-weight chain acids, alcohols and furfurals. Such columns resulted in a good separation with long lifetime, wide pH operating range and low fouling issues.
Applied Sciences, 2022
The incorporation of coal fly ash (CFA) in fired clay bricks (FCBs), as a clay replacement, contr... more The incorporation of coal fly ash (CFA) in fired clay bricks (FCBs), as a clay replacement, contributes toward cleaner production practices. CFA disposal is an important issue worldwide due to its huge volume and to its potential negative environmental impacts, and currently does not have
a recovery route due to its high concentration in unburned materials. In this study, the impact of the incorporation of two CFA, with different content of unburned carbon, FAA (low LOI) and FAB (high LOI) in FCBs, from a technical and environmental point of view was conducted. Unburned carbon plays an important role on the final properties of FCBs. The thermal decomposition during the firing process promotes an increase of water absorption, decreasing the flexural strength as the porosity increases, although the technical and mechanical properties of samples containing up to 30% FAA and percentages of 20% FAB are acceptable. The leaching behaviour showed an immobilisation of Cr and Se in FCBs while Mo reduced its mobility to values below non-hazardous limits. Acid gas emission values do not exceed the reference emission value, except for SO2 emissions while the level of CO2 emissions must be estimated based on the total annual production of the ceramic factory.
ABSTRACT: Physico-chemical and biological processes can be used to transform different pulp and p... more ABSTRACT: Physico-chemical and biological processes can be used to transform different pulp and paper industries through integrated forest biorefineries in order to valorise all of the main fractions of the lignocellulosic biomass (cellulose, hemicellulose and lignin). In this work, hydrolysis and fractionation processes have been studied in a sulphite pulp mill to obtain not only dissolving pulp from the cellulose but also lignosulphonates from the lignin and fermentation products from the hemicellulose. Delignification and hydrolysis experiments have been carried out at laboratory scale in order to increase the valorization opportunities and trying to decrease the inhibitors in the final by-product. In addition, detoxification or separation treatments have been developed in order to separate the lignosulphonates and other inhibitors from the sugar substrate.RESUMEN:Diferentes procesos físico-químico y biológicos se pueden utilizar para transformar la industria de la pasta y celulo...
VII Simposio Iberoamericano #R##N#en Ingeniería de Residuos : #R##N#Hacia una economía circular, Santander, Universidad de Cantabria, 2017, 2017
RESUMEN: Es bien sabido que durante la producción de pasta dissolving de alta pureza, se genera u... more RESUMEN: Es bien sabido que durante la producción de pasta dissolving de alta pureza, se genera un residuo denominado licor gastado de cocción altamente rico en azúcares. Este hecho, convierte la industria del pasteado en potenciales biorrefinerías lignocelulósicas por medio de la integración de algunas modificaciones en el proceso actual. Esta tesis contribuye a la transformación de una industria de pasta al sulfito ácido localizada en la región de Cantabria (España) en una moderna biorrefinería forestal. En primer lugar se estudiaron los procesos de digestión y blanqueo. Posteriormente, el residuo principal (licor gastado al sulfito) fue caracterizado, externamente hidrolizado y detoxificado para intensificar el rendimiento y la productividad de la fermentación del mismo. La transformación propuesta preserva las propiedades de calidad de la pasta, logrando mejoras en la conversión de los azúcares y en la separación de otros subproductos para su posterior valorización.ABSTRACT: It ...
VII Simposio Iberoamericano #R##N#en Ingeniería de Residuos : #R##N#Hacia una economía circular, Santander, Universidad de Cantabria, 2017, 2017
Materials, 2016
The complete bioconversion of the carbohydrate fraction is of great importance for a lignocellulo... more The complete bioconversion of the carbohydrate fraction is of great importance for a lignocellulosic-based biorefinery. However, due to the structure of the lignocellulosic materials, and depending basically on the main parameters within the pretreatment steps, numerous byproducts are generated and they act as inhibitors in the fermentation operations. In this sense, the impact of inhibitory compounds derived from lignocellulosic materials is one of the major challenges for a sustainable biomass-to-biofuel and-bioproduct industry. In order to minimise the negative effects of these compounds, numerous methodologies have been tested including physical, chemical, and biological processes. The main physical and chemical treatments have been studied in this work in relation to the lignocellulosic material and the inhibitor in order to point out the best mechanisms for fermenting purposes. In addition, special attention has been made in the case of lignocellulosic hydrolysates obtained by chemical processes with SO 2 , due to the complex matrix of these materials and the increase in these methodologies in future biorefinery markets. Recommendations of different detoxification methods have been given.
Biomass and Bioenergy, 2021
The transformation of fermentable sugars provided from lignocellulosic wastes into biofuels or bi... more The transformation of fermentable sugars provided from lignocellulosic wastes into biofuels or bioproducts is a key point at second-generation biorefineries. Spent sulfite liquor is a xylose-rich hydrolysate constituting the main residue of sulfite mills producing dissolving cellulose. Due to the presence of the inhibitors in the spent liquor, the most promising valorization options require detoxification before sugars bioconversion. In this work, a multi criteria analysis was implemented to select techno-economic and socio-environmental feasible detoxification alternatives that can be adapted to a wide variety of fermenting scenarios. Total inhibitors removal, phenolics removal, acetic acid removal, lignosulfonates removal, total sugar losses, fixed capital invested, manufacturing costs, waste toxicity, social acceptance, and employment were chosen as the most relevant criteria. The maximum allowable concentration of undesirable inhibitors cannot be established with a general character, and thereby decision-making tools result in feasible and efficient solutions. From a technical viewpoint best solution was anionic resins with a score of 0.68; the most economical alternative was the overliming with a score of 0.76; finally, from a socio-environmental perspective, overliming reached the highest score of 0.78. In addition, three spent liquor biorefinery models were proposed. Based on the multicriteria analysis and based on the inhibitor's concentration affecting fermentation yields and productivity, the best detoxification alternatives were (1) anionic resins for polyhydroxyalkanoate production; (2) activated carbon for ethanol biorefinery; (3) overliming for xylitol biorefinery.
Sustainability
Solidification/stabilization (S/S) of acid waste using Ordinary Portland Cement (OPC) is widely i... more Solidification/stabilization (S/S) of acid waste using Ordinary Portland Cement (OPC) is widely implemented, but, due to the impact on climate change, alternative methods are being investigated. In this work, first, the feasibility of using coal fly-ash/clay-based geopolymers for the S/S of Zn plant residues (ZPR), Cadmium Sponge (CS), and Anode Mud (AM) is proposed as a treatment prior to disposal in landfills. Different variables, such as the type of processing, molding (as-received waste), and pressing (dried waste), and activators, a commercial and an alternative residual sodium carbonate, have been studied. The technical and environmental assessments of the S/S process by means of compressive strength and the leaching of critical pollutants have been monitored. Immobilization efficiencies of Cd and Zn higher than 99% have been obtained by dosing 50% of the acid waste, 6 M NaOH solution (20 min contact time), cured at 75 °C (48 h) and at room temperature (28 days), achieving in ...
Applied Sciences
The incorporation of coal fly ash (CFA) in fired clay bricks (FCBs), as a clay replacement, contr... more The incorporation of coal fly ash (CFA) in fired clay bricks (FCBs), as a clay replacement, contributes toward cleaner production practices. CFA disposal is an important issue worldwide due to its huge volume and to its potential negative environmental impacts, and currently does not have a recovery route due to its high concentration in unburned materials. In this study, the impact of the incorporation of two CFA, with different content of unburned carbon, FAA (low LOI) and FAB (high LOI) in FCBs, from a technical and environmental point of view was conducted. Unburned carbon plays an important role on the final properties of FCBs. The thermal decomposition during the firing process promotes an increase of water absorption, decreasing the flexural strength as the porosity increases, although the technical and mechanical properties of samples containing up to 30% FAA and percentages of 20% FAB are acceptable. The leaching behaviour showed an immobilisation of Cr and Se in FCBs while...
Cellulose, 2020
Choline chloride-based deep eutectic solvents are widely used in biomass processing. In this work... more Choline chloride-based deep eutectic solvents are widely used in biomass processing. In this work, four different green solvent mixtures were used as pre-treatment of acid sulphite dissolving pulp with the hypothesis of increasing the possibilities to produce viscose fibres and decreasing the use of the harmful and toxic carbon disulphide in the process. The experiments were performed at two different pulp to solvent mass ratios. Pulp quality parameters were also measured to determine the suitability of the pre-treatment: α-cellulose, viscosity, lignin and pentosan content. In addition, X-ray diffraction analysis of pulps at the best solid to liquid ratio was performed to obtain the influence of the crystallinity index. Best results were obtained with the use of lactic acid, with reactivity values close to 94%, giving a reduction of CS2 usage of 15.83%. Furthermore, a linear relationship between the crystallinity index calculated by the XRD and reactivity with a regression factor of 0.87 was found.
Journal of Chemical Technology & Biotechnology, 2021
Applied Sciences, 2021
The recent recovery processes of electric arc furnace dust (EAFD) include stabilization within ma... more The recent recovery processes of electric arc furnace dust (EAFD) include stabilization within materials with potential uses in the construction sector. The stabilization of EAFD by alkaline activation of different alumina-silicates, resulting in low-cost and environmentally friendly materials. The leaching standards within the different European regulations allow evaluating waste materials and products. This work aims to study the introduction of EAFD in FA–clay geopolymers, assessing the environmental and geochemical behavior in two different scenarios, disposal, and utilization. For it, the compliance equilibrium-based batch test (EN 12457-2) and pH dependence test (EN 14429) have been used. The dosages of EAFD in the geopolymeric matrix are 5% to 20% with curing temperatures of 75 °C and 225 °C. The introduction of EAFD favors the development of the flexural strength. From the environmental point of view, metals related to EAFD, such as Zn, Pb, or Cu, are retained in the matrix....
BioResources, 2018
A totally chlorine free (TCF) bleaching sequence was studied for an acid sulfite pulp mill that p... more A totally chlorine free (TCF) bleaching sequence was studied for an acid sulfite pulp mill that produces dissolving pulps. Laboratory analyses of the last two bleaching stages, an oxidant-reinforced alkaline extraction stage (EOP), and a subsequent pressurized peroxide with oxygen stage (PO), were performed on a eucalypt pulp that had been delignified by an ozone (Z) stage in the pulp mill. The goal was to predict the optimal costs and operational conditions for the (EOP)(PO) partial bleach sequence for three different specialty pulp products. Four independent variables affecting the pulp quality properties were examined for each stage (i.e., reaction temperature, reaction time, NaOH dosage and H2O2 dosage). The dependent variables were various pulp properties, such as intrinsic pulp viscosity, alpha-cellulose content, kappa number, and GE brightness. Three scenarios were considered to optimize the bleaching process, which related to a regenerated cellulose product (viscose) that is...
Waste and Biomass Valorization, 2015
This paper contains data related to the research paper entitled "Organic two-phase system based o... more This paper contains data related to the research paper entitled "Organic two-phase system based on acetonitrile þ water þ polyvinylpyrrolidone, a novel concept of liquid-liquid equilibrium: phase diagrams and phenolic compounds partitioning". Data of phase equilibrium were obtained using the cloud point method. After this step, some blending points were chosen to perform the phenolic compounds partitioning (gallic acid, quercetin dihydrate and cyanidin 3-O-glucoside chloride)
Journal of Chemistry, 2015
The evolution of lignin, five- and six-carbon sugars, and other decomposition products derived fr... more The evolution of lignin, five- and six-carbon sugars, and other decomposition products derived from hemicelluloses and cellulose was monitored in a sulfite pulp mill. The wastewater streams were characterized and the mass balances throughout digestion and total chlorine free bleaching stages were determined. Summative analysis in conjunction with pulp parameters highlights some process guidelines and valorization alternatives towards the transformation of the traditional factory into a lignocellulosic biorefinery. The results showed a good separation of cellulose (99.64%) during wood digestion, with 87.23% of hemicellulose and 98.47% lignin dissolved into the waste streams. The following steps should be carried out to increase the sugar content into the waste streams: (i) optimization of the digestion conditions increasing hemicellulose depolymerization; (ii) improvement of the ozonation and peroxide bleaching stages, avoiding deconstruction of the cellulose chains but maintaining i...
Carbohydrate Polymers, 2015
Spent sulfite liquor is a lignocellulosic waste obtained after the sulfite pulping process. It is... more Spent sulfite liquor is a lignocellulosic waste obtained after the sulfite pulping process. It is mainly formed by sugars and lignosulfonates which are isolated from the pulp during the cooking process. The current work investigates the kinetic modeling of the sulfite process from a biorefinery point of view since monosaccharides present in the spent liquor can be used as a raw material in further biorefinery processes to produce other value-added products. Kinetic parameters of carbohydrate degradation have been determined following sugar and inhibitors from wood to spent liquor, using laboratory scale reactors and different temperatures, 130, 140 and 150 °C. Three types of reaction schemes were developed. Kinetic parameters were obtained for each one using first and n order reactions, using Aspen Custom Modeler. Results show that the best temperature to be used in the process is 130 °C, giving the maximum sugar conversion, 33.91 mol% and obtaining 13.81 mol% of decomposition products.
Journal of Biotechnology, 2012
Biotechnology Reports, 2017
Waste from pulp and paper mills consist of sugar-rich fractions comprising hemicellulose derivati... more Waste from pulp and paper mills consist of sugar-rich fractions comprising hemicellulose derivatives and cellulose by-products. A complete characterisation of the waste streams is necessary to study the possibilities of an existing mill. In this work, four chromatographic methods have been developed to obtain the most suitable chromatographic method conditions for measuring woody feedstocks, lignocellulosic hydrolysates and cellulose pulp in sulphite pulping processes. The analysis of major and minor monosaccharides, aliphatic carboxylic acids and furfurals has been optimised. An important drawback of the spent liquors generated after sulphite pulping is their acidic nature, high viscosity and adhesive properties that interfere in the column lifetime. This work recommends both a CHO-782Pb column for the sugar analysis and an SH-1011 resin-based cross-linked gel column to separate lowmolecular-weight chain acids, alcohols and furfurals. Such columns resulted in a good separation with long lifetime, wide pH operating range and low fouling issues.
Applied Sciences, 2022
The incorporation of coal fly ash (CFA) in fired clay bricks (FCBs), as a clay replacement, contr... more The incorporation of coal fly ash (CFA) in fired clay bricks (FCBs), as a clay replacement, contributes toward cleaner production practices. CFA disposal is an important issue worldwide due to its huge volume and to its potential negative environmental impacts, and currently does not have
a recovery route due to its high concentration in unburned materials. In this study, the impact of the incorporation of two CFA, with different content of unburned carbon, FAA (low LOI) and FAB (high LOI) in FCBs, from a technical and environmental point of view was conducted. Unburned carbon plays an important role on the final properties of FCBs. The thermal decomposition during the firing process promotes an increase of water absorption, decreasing the flexural strength as the porosity increases, although the technical and mechanical properties of samples containing up to 30% FAA and percentages of 20% FAB are acceptable. The leaching behaviour showed an immobilisation of Cr and Se in FCBs while Mo reduced its mobility to values below non-hazardous limits. Acid gas emission values do not exceed the reference emission value, except for SO2 emissions while the level of CO2 emissions must be estimated based on the total annual production of the ceramic factory.
Dissolving cellulose is a low-yield chemical pulp (30-35 %) with a high alpha-cellulose content (... more Dissolving cellulose is a low-yield chemical pulp (30-35 %) with a high alpha-cellulose content (91-93 %) and relatively low hemicellulose (1-10 %) and lignin (<0.05 %) content.Sugar-rich residual streams generated during sulphite pulping for dissolving pulp manufacture convert such factories into potential lignocellulosic biorefineries by integrating several modifications into the current processes by means of chemical, thermo-chemical or biochemical pathways.
Mixed five and six carbon sugar platforms produced from the hydrolysis of hemicelluloses serve as substrate for biological conversion providing fuels as hydrogen or ethanol, biopolymers, and chemicals as lactic, succinic, or levulinic acids, sorbitol, furfural or xylitol. Within this hypothesis, this dissertation evaluates the possibilities of producing fermentable substrate stream, transforming an acid sulphite pulping industry located in Cantabria (Spain) into a modern lignocellulosic biorefinery.
The main objective of this thesis is to study the acid sulphite process in a factory in the north of Spain and to identify the factory improvements within the biorefinery concept.
First several physico-chemical characterisation methods of the feedstock (Eucalyptus globulus), product (dissolving pulp) and waste streams (hydrolysates) were carried out. In addition, four chromatographic methods for carbohydrate and derivative quantification of woody samples were set up.
Afterwards, mass balance of the main components was carried out at industrial scale in order to give some conclusions about the fractionation processes and valorisation opportunities in the factory. From the study of the industrial digestion and bleaching processes, it can be concluded that there is a good cellulose separation during wood digestion (99.64 %) with the presence of 87.23 % hemicellulose and 98.47 % lignin in the spent liquor. As an example of valorisation option, 0.183 L of second-generation ethanol per kilogram of dry spent liquor can be obtained by the mill.
The following step was to study the sulphite digestion stage and the effect of the most important parameters on the final dissolved sugars. The best results of the digestion step increased the amount of total monosaccharide of the spent liquor at 1.01T of dwell temperature, 0.196R and 6.20 % total SO2. Experimental cooking results were modelled giving theoretical increases of 7.33 % of monosaccharides within the spent liquor.
Liquid samples were externally hydrolysed. Diluted-acid hydrolysis and concentrated-acid hydrolysis were chosen as the most adequate depolymerisation treatments. A factorial design of experiments was done to study the effect of temperature, acid concentration, acid-to-liquor ratio and time on hemicellulose depolymerisation. Diluted-acid hydrolysis showed the best results getting monosaccharide improvements of 7.9 % using 0.5 % w/w of H2SO4 at 80 ºC for 60 minutes with acid-to-liquor ratio of 10 v/v.
Finally, to separate sugars from the rest of fermenting inhibitors (lignin-derived and carbohydrates-derived constituents) several detoxification techniques were implemented. Overliming, adsorption, ion exchange and liquid-liquid extraction were studied. Treatment with anionic resins was proposed as the best solution with maximum total inhibitor removals of 91.8 %. In addition, six regeneration cycles of resin were proposed for phenolics and lignosulphonate recovery. Adsorption was also adequate for lignosulphonate, phenolics and acetic acid removals reaching a maximum of 74.5 % of acetic acid removal using activated charcoal. However, adsorption processes gave high losses of sugar in the hydrolysate.
Maximum bioethanol potentials of 1.231, 1.818 and 1.799 L.EtOH/Kg.dry SSL were obtained after detoxification with overliming and liquid-liquid extraction with chloroform and diethyl ether.
This research proposes some recommendations and improvements in the factory in order to valorise the residual streams, not only enhancing the separation of sugars from the rest of wood constituents for fermenting purposes, but also maintaining the quality properties of the main product, dissolving pulp. Based on the whole study, diluted-acid hydrolysis, detoxification, fermentation and purification steps should be incorporated to the current sulphite mill for carbohydrates valorisation within the biorefinery concept.