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Papers by Esteban Chornet

Research paper thumbnail of Citizen Involvement in Waste Management: An Application of The STOPER Model via an Informed Consensus Approach

Environmental Management, 1999

Waste management planning and implementation is not only a technological issue, but a social and ... more Waste management planning and implementation is not only a technological issue, but a social and political one as well. In this paper, we discuss a proposal to rethink certain aspects about waste management planning and implementation. Specifically, we present a framework whereby the ordinary citizen can proactively and constructively participate in the decision-making process. After briefly discussing the STOPER research team and certain limits inherent in current waste-management practices, we propose a mode of consultation known as the informed consensus approach. We assert that this approach incorporates social perceptions of key intervenors such as experts, decision makers, interest groups, and ordinary citizens and that this can enrich the decision-making process concerning complex environmental issues such as waste management. We focus our presentation on the results of the application of an informed consensus approach to waste management strategies in the municipality of Sherbrooke (Qué bec, Canada).

Research paper thumbnail of Production of Hydrogen from Biomass-Derived Liquids

Progress in Thermochemical Biomass Conversion

Research paper thumbnail of Compensation effect in the thermal decomposition of cellulosic materials

Thermochimica Acta, 1980

where w is the weight or mass of pyrolyzing sample at any time t; A is the frequency factor; E is... more where w is the weight or mass of pyrolyzing sample at any time t; A is the frequency factor; E is the activation energy; Q is the reaction order, and k is the rate constant. Our analysis of substantial and diversified amounts of data has established a clear linear relationship between the variables log A and E, as shall be shown later. Such dependence is known as a compensation effect, expressed by the following equation

Research paper thumbnail of Improved Alkaline Oxidation Process for the Production of Aldehydes (Vanillin and Syringaldehyde) from Steam-Explosion Hardwood Lignin

Industrial & Engineering Chemistry Research, 1994

The production of aldehydes from a steam-explosion hardwood lignin is the main objective of this ... more The production of aldehydes from a steam-explosion hardwood lignin is the main objective of this paper. It is demonstrated that the combined aldehydes yield (vanillin + syringaldehyde + hydroxybenzaldehyde) can reach 14.6 wt % of the lignin isolated from the steam-explosion process. This represents 12.2 wt % of the Klason lignin present in the initial hardwood (Populus tremuloides) and 2.5 wt % of the dry wood. The process steps are relatively simple: aqueous alkaline (13.5 wt 76 NaOH) oxidation (pure 02) of lignin in the presence of Cu2+ and Fe3* as catalysts, a t 170 O C and with 10 min as reaction time. The high yields of aldehydes observed in our work far exceed those obtained in the conventional alkaline air oxidation of spent sulfite liquors. Our results support the concept that biomass-derived oxyaromatic chemicals via improved process strategies may soon challenge existing petroleum-derived routes (vanillin is currently produced via the sequence benzene cumenephenolguaiacol-+ vanillin).

Research paper thumbnail of Hydrogen by catalytic steam reforming of liquid byproducts from biomass thermoconversion processes

Industrial & engineering …, 2002

Biomass, a product of photosynthesis, is a renewable resource that can be used for sustainable pr... more Biomass, a product of photosynthesis, is a renewable resource that can be used for sustainable production of hydrogen. We propose an approach that combines production of hydrogen with valuable coproducts and shows promising economics. The concept is based on a ...

Research paper thumbnail of Evidence for the heterogeneity of glycol lignin

Industrial & Engineering Chemistry Research, 1991

ABSTRACT

Research paper thumbnail of Mechanism of Dilute Acid Hydrolysis of Cellulose Accounting for its Degradation in the Solid State

Journal of Wood Chemistry and Technology, 1992

It is known that dilute acid hydrolysis of cellulose at high temperature results in yields not ex... more It is known that dilute acid hydrolysis of cellulose at high temperature results in yields not exceeding 60–65% of the potential glucose. All the models presented in the literature are based on the sequence: cellulose #x00BB; glucose #x00BB; degradation products. The underlying assumption of this sequence is that the unconverted cellulose retains its chemical integrity during the course of the

Research paper thumbnail of Fractionation of Populus tremuloides at the pilot plant scale: optimization of steam pretreatment conditions using the STAKE II technology

Bioresource Technology, 1991

steam explosion processes are fundamentally hydrolytic' in nature. Fractionation of a prototype h... more steam explosion processes are fundamentally hydrolytic' in nature. Fractionation of a prototype hardwood, Populus tremuloides, was optimized in a 4 t/h pilot plant STAKE H unit located in Sherbrooke, QuObec. The aim was to find operational zones which maximized the recoveries of hemicelluloses (pentosans), lignin and cellulose. A phenomenological approach, based on the definition of a severity parameter R = t *exp[(T-100)/14"75] which combines time, t (min), and temperature, T (°C), to express the severity of a given pretreatment, was developed. Performance curves, using the R o parameter, have been experimentally determined. These indicated that the maximum recovery of pentosans is 65% of the potential at logtoR o =3"8. Under these conditions, lignin recovery by caustic extraction was about 80% of total lignin. Cellulose was completely recovered at this severity but needed to be bleached to achieve its natural coloration. At severities both ,greater and smaller than lo&oR o =3.8 pentosans recovery decreased. The celhdose det4ved from the steam fractionation process was rapidly depolymerized as severity increased, whilst its enzymatic digestibility was close to theoretical at severities beyond lo&oR,, =3"2. The results" obtained suggest that *To whom correspondence should be addressed.

Research paper thumbnail of Statistical study on the batch conversion of estevan lignite into oils using carbon monoxide and hydrogen mixtures

The Canadian Journal of Chemical Engineering, 1980

Research paper thumbnail of Thermolysis of glycol lignin in the presence of tetralin

Canadian Journal of Chemical Engineering, 1993

An organosolv (ethylene glycol) hardwood lignin has been thermally treated in the presence of tet... more An organosolv (ethylene glycol) hardwood lignin has been thermally treated in the presence of tetralin, a hydrogen donor solvent. The effects of reaction temperature and time on product distribution were studied as a function of a seventy index, Xc = ℓn (Rω with Rω = Δt t × exp [(Tr - Tb)/ω] where Δt = time, Tr = reaction temperature, Tb = base temperature, and ω = characteristic parameter. Under the conditions used, up to 60% of the lignin can be converted to liquid and gaseous products. Syringols, guaiacols, aromatic aldehydes and ketones predominate at low treatment severities whilst phenol, catechol and their methyl and ethyl derivatives are the main monomers at high severities. Comparison of our data with parallel works is shown to be effectively done through the severity index, Xc.Une lignine solvolytique (éthylène glycol) a été traitée thermiquement en présence de tétraline, un donneur d'hydrogène. Le seffets de température et temps sur la distribution des produits ont ét...

Research paper thumbnail of Correlation between polystyrene molecular weights and a characteristic temperature derived from the thermogravimetric weight loss curves

Thermochimica Acta, 1989

... 5 B. Dickens, Polym. Degrad. Stabil., 2 (1980) 249. 6 C. Bouster, C. Cornel, P. Vermande and ... more ... 5 B. Dickens, Polym. Degrad. Stabil., 2 (1980) 249. 6 C. Bouster, C. Cornel, P. Vermande and J. Veron, J. Therm. Anal., 20 (1981) 115. 7 DA Anderson and ES Freeman, J. Polym. Sci., 54 (1961) 253. 8 BV Kokta, JL Valade and WN Martini, J. Appl. Polym. ...

Research paper thumbnail of Citizen Involvement in Waste Management: An Application of The STOPER Model via an Informed Consensus Approach

Environmental Management, 1999

Waste management planning and implementation is not only a technological issue, but a social and ... more Waste management planning and implementation is not only a technological issue, but a social and political one as well. In this paper, we discuss a proposal to rethink certain aspects about waste management planning and implementation. Specifically, we present a framework whereby the ordinary citizen can proactively and constructively participate in the decision-making process. After briefly discussing the STOPER research team and certain limits inherent in current waste-management practices, we propose a mode of consultation known as the informed consensus approach. We assert that this approach incorporates social perceptions of key intervenors such as experts, decision makers, interest groups, and ordinary citizens and that this can enrich the decision-making process concerning complex environmental issues such as waste management. We focus our presentation on the results of the application of an informed consensus approach to waste management strategies in the municipality of Sherbrooke (Qué bec, Canada).

Research paper thumbnail of Production of Hydrogen from Biomass-Derived Liquids

Progress in Thermochemical Biomass Conversion

Research paper thumbnail of Compensation effect in the thermal decomposition of cellulosic materials

Thermochimica Acta, 1980

where w is the weight or mass of pyrolyzing sample at any time t; A is the frequency factor; E is... more where w is the weight or mass of pyrolyzing sample at any time t; A is the frequency factor; E is the activation energy; Q is the reaction order, and k is the rate constant. Our analysis of substantial and diversified amounts of data has established a clear linear relationship between the variables log A and E, as shall be shown later. Such dependence is known as a compensation effect, expressed by the following equation

Research paper thumbnail of Improved Alkaline Oxidation Process for the Production of Aldehydes (Vanillin and Syringaldehyde) from Steam-Explosion Hardwood Lignin

Industrial & Engineering Chemistry Research, 1994

The production of aldehydes from a steam-explosion hardwood lignin is the main objective of this ... more The production of aldehydes from a steam-explosion hardwood lignin is the main objective of this paper. It is demonstrated that the combined aldehydes yield (vanillin + syringaldehyde + hydroxybenzaldehyde) can reach 14.6 wt % of the lignin isolated from the steam-explosion process. This represents 12.2 wt % of the Klason lignin present in the initial hardwood (Populus tremuloides) and 2.5 wt % of the dry wood. The process steps are relatively simple: aqueous alkaline (13.5 wt 76 NaOH) oxidation (pure 02) of lignin in the presence of Cu2+ and Fe3* as catalysts, a t 170 O C and with 10 min as reaction time. The high yields of aldehydes observed in our work far exceed those obtained in the conventional alkaline air oxidation of spent sulfite liquors. Our results support the concept that biomass-derived oxyaromatic chemicals via improved process strategies may soon challenge existing petroleum-derived routes (vanillin is currently produced via the sequence benzene cumenephenolguaiacol-+ vanillin).

Research paper thumbnail of Hydrogen by catalytic steam reforming of liquid byproducts from biomass thermoconversion processes

Industrial & engineering …, 2002

Biomass, a product of photosynthesis, is a renewable resource that can be used for sustainable pr... more Biomass, a product of photosynthesis, is a renewable resource that can be used for sustainable production of hydrogen. We propose an approach that combines production of hydrogen with valuable coproducts and shows promising economics. The concept is based on a ...

Research paper thumbnail of Evidence for the heterogeneity of glycol lignin

Industrial & Engineering Chemistry Research, 1991

ABSTRACT

Research paper thumbnail of Mechanism of Dilute Acid Hydrolysis of Cellulose Accounting for its Degradation in the Solid State

Journal of Wood Chemistry and Technology, 1992

It is known that dilute acid hydrolysis of cellulose at high temperature results in yields not ex... more It is known that dilute acid hydrolysis of cellulose at high temperature results in yields not exceeding 60–65% of the potential glucose. All the models presented in the literature are based on the sequence: cellulose #x00BB; glucose #x00BB; degradation products. The underlying assumption of this sequence is that the unconverted cellulose retains its chemical integrity during the course of the

Research paper thumbnail of Fractionation of Populus tremuloides at the pilot plant scale: optimization of steam pretreatment conditions using the STAKE II technology

Bioresource Technology, 1991

steam explosion processes are fundamentally hydrolytic' in nature. Fractionation of a prototype h... more steam explosion processes are fundamentally hydrolytic' in nature. Fractionation of a prototype hardwood, Populus tremuloides, was optimized in a 4 t/h pilot plant STAKE H unit located in Sherbrooke, QuObec. The aim was to find operational zones which maximized the recoveries of hemicelluloses (pentosans), lignin and cellulose. A phenomenological approach, based on the definition of a severity parameter R = t *exp[(T-100)/14"75] which combines time, t (min), and temperature, T (°C), to express the severity of a given pretreatment, was developed. Performance curves, using the R o parameter, have been experimentally determined. These indicated that the maximum recovery of pentosans is 65% of the potential at logtoR o =3"8. Under these conditions, lignin recovery by caustic extraction was about 80% of total lignin. Cellulose was completely recovered at this severity but needed to be bleached to achieve its natural coloration. At severities both ,greater and smaller than lo&oR o =3.8 pentosans recovery decreased. The celhdose det4ved from the steam fractionation process was rapidly depolymerized as severity increased, whilst its enzymatic digestibility was close to theoretical at severities beyond lo&oR,, =3"2. The results" obtained suggest that *To whom correspondence should be addressed.

Research paper thumbnail of Statistical study on the batch conversion of estevan lignite into oils using carbon monoxide and hydrogen mixtures

The Canadian Journal of Chemical Engineering, 1980

Research paper thumbnail of Thermolysis of glycol lignin in the presence of tetralin

Canadian Journal of Chemical Engineering, 1993

An organosolv (ethylene glycol) hardwood lignin has been thermally treated in the presence of tet... more An organosolv (ethylene glycol) hardwood lignin has been thermally treated in the presence of tetralin, a hydrogen donor solvent. The effects of reaction temperature and time on product distribution were studied as a function of a seventy index, Xc = ℓn (Rω with Rω = Δt t × exp [(Tr - Tb)/ω] where Δt = time, Tr = reaction temperature, Tb = base temperature, and ω = characteristic parameter. Under the conditions used, up to 60% of the lignin can be converted to liquid and gaseous products. Syringols, guaiacols, aromatic aldehydes and ketones predominate at low treatment severities whilst phenol, catechol and their methyl and ethyl derivatives are the main monomers at high severities. Comparison of our data with parallel works is shown to be effectively done through the severity index, Xc.Une lignine solvolytique (éthylène glycol) a été traitée thermiquement en présence de tétraline, un donneur d'hydrogène. Le seffets de température et temps sur la distribution des produits ont ét...

Research paper thumbnail of Correlation between polystyrene molecular weights and a characteristic temperature derived from the thermogravimetric weight loss curves

Thermochimica Acta, 1989

... 5 B. Dickens, Polym. Degrad. Stabil., 2 (1980) 249. 6 C. Bouster, C. Cornel, P. Vermande and ... more ... 5 B. Dickens, Polym. Degrad. Stabil., 2 (1980) 249. 6 C. Bouster, C. Cornel, P. Vermande and J. Veron, J. Therm. Anal., 20 (1981) 115. 7 DA Anderson and ES Freeman, J. Polym. Sci., 54 (1961) 253. 8 BV Kokta, JL Valade and WN Martini, J. Appl. Polym. ...