2010
Artículos de revista
Alzueta, María U; Serinyel, Z; Simmie, J M; Curran, Henry J
Oxidation of acetone and its interaction with nitric oxide Artículo de revista
En: Energy and Fuels, vol. 24, no 3, pp. 1511–1520, 2010, ISSN: 08870624.
@article{Alzueta2010,
title = {Oxidation of acetone and its interaction with nitric oxide},
author = {María U Alzueta and Z Serinyel and J M Simmie and Henry J Curran},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ef9015284},
issn = {08870624},
year = {2010},
date = {2010-03-01},
journal = {Energy and Fuels},
volume = {24},
number = {3},
pages = {1511--1520},
publisher = {American Chemical Society},
abstract = {An experimental and kinetic modeling study of the oxidation of acetone, both in the absence and the presence ofNO, has been performed under flow reactor conditions in the temperature range of 700-1500K and for different stoichiometries, ranging from fuel-rich to fuel-lean environments. The impact of stoichiometry on flow reactor data and ignition delay times has been studied, whereas the influence of NOhas been analyzed under flow reactor conditions.Aliterature kinetic detailedmodel, slightlymodified in the present work, has been used to simulate and explain the experimental findings. textcopyright 2010 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
An experimental and kinetic modeling study of the oxidation of acetone, both in the absence and the presence ofNO, has been performed under flow reactor conditions in the temperature range of 700-1500K and for different stoichiometries, ranging from fuel-rich to fuel-lean environments. The impact of stoichiometry on flow reactor data and ignition delay times has been studied, whereas the influence of NOhas been analyzed under flow reactor conditions.Aliterature kinetic detailedmodel, slightlymodified in the present work, has been used to simulate and explain the experimental findings. textcopyright 2010 American Chemical Society.
Giménez-López, Jorge; Bilbao, Rafael; Alzueta, María U
HCN oxidation in an O2/CO2 atmosphere: An experimental and kinetic modeling study Artículo de revista
En: Combustion and Flame, vol. 157, no 2, pp. 267–276, 2010, ISSN: 00102180.
@article{Gimenez-Lopez2010,
title = {HCN oxidation in an O2/CO2 atmosphere: An experimental and kinetic modeling study},
author = {Jorge Giménez-López and Rafael Bilbao and María U Alzueta},
doi = {10.1016/j.combustflame.2009.07.016},
issn = {00102180},
year = {2010},
date = {2010-02-01},
journal = {Combustion and Flame},
volume = {157},
number = {2},
pages = {267--276},
publisher = {Elsevier},
abstract = {HCN is one of the most important intermediates in NOx chemistry including formation and removal processes and the knowledge of HCN oxidation is thus very important to minimize NOx emissions. The present work aims to evaluate the oxidation behavior of HCN in an O2/CO2 atmosphere, due to the lack of studies at these specific operating conditions and the increasing importance of the oxy-fuel combustion processes, characterized by an O2/CO2 combustion atmosphere instead of air. With this purpose, a flow reactor experimental and kinetic modeling study of the oxidation of HCN under CO2 diluted conditions, in the 900-1450 K temperature range and for different stoichiometries, ranging from very reducing to oxidizing conditions, has been performed. The large experimental differences observed in the O2/CO2 atmosphere in comparison to traditional air-fired combustion corroborate the importance of the HCN oxidation study in an O2/CO2 environment. The presence of high CO2 concentration levels clearly inhibits HCN oxidation, since CO2 competes with O2 for atomic hydrogen through the CO2 + H ⇌ CO + OH reaction. The experimental results show the oxidation regime of HCN for different stoichiometries, analyzing the formation of the main products of the process: CO, NO, N2, N2O and HNCO. The higher availability of oxygen increases the HCN conversion, even though the onset temperature for reaction is almost similar at any stoichiometry studied. The mechanism used for calculations was that developed by Dagaut et al. [P. Dagaut, P. Glarborg, M.U. Alzueta, Prog. Energy Combust. Sci. 34 (2008) 1-46] for the oxidation of HCN in air combustion, updated in the present work to take into account the presence of an O2/CO2 combustion atmosphere. In general, the modified model gives a reasonably good description of the experiments performed. textcopyright 2009 The Combustion Institute.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
HCN is one of the most important intermediates in NOx chemistry including formation and removal processes and the knowledge of HCN oxidation is thus very important to minimize NOx emissions. The present work aims to evaluate the oxidation behavior of HCN in an O2/CO2 atmosphere, due to the lack of studies at these specific operating conditions and the increasing importance of the oxy-fuel combustion processes, characterized by an O2/CO2 combustion atmosphere instead of air. With this purpose, a flow reactor experimental and kinetic modeling study of the oxidation of HCN under CO2 diluted conditions, in the 900-1450 K temperature range and for different stoichiometries, ranging from very reducing to oxidizing conditions, has been performed. The large experimental differences observed in the O2/CO2 atmosphere in comparison to traditional air-fired combustion corroborate the importance of the HCN oxidation study in an O2/CO2 environment. The presence of high CO2 concentration levels clearly inhibits HCN oxidation, since CO2 competes with O2 for atomic hydrogen through the CO2 + H ⇌ CO + OH reaction. The experimental results show the oxidation regime of HCN for different stoichiometries, analyzing the formation of the main products of the process: CO, NO, N2, N2O and HNCO. The higher availability of oxygen increases the HCN conversion, even though the onset temperature for reaction is almost similar at any stoichiometry studied. The mechanism used for calculations was that developed by Dagaut et al. [P. Dagaut, P. Glarborg, M.U. Alzueta, Prog. Energy Combust. Sci. 34 (2008) 1-46] for the oxidation of HCN in air combustion, updated in the present work to take into account the presence of an O2/CO2 combustion atmosphere. In general, the modified model gives a reasonably good description of the experiments performed. textcopyright 2009 The Combustion Institute.
Valiente, Ana; Medrano, José A; Oliva, Miriam; Ruiz, Joaquín; García, Lucía; Arauzo, Jesús
Bioenergy II: Hydrogen production by aqueous-phase reforming Artículo de revista
En: International Journal of Chemical Reactor Engineering, vol. 8, no 1, 2010, ISSN: 15426580.
@article{Valiente2010,
title = {Bioenergy II: Hydrogen production by aqueous-phase reforming},
author = {Ana Valiente and José A Medrano and Miriam Oliva and Joaquín Ruiz and Lucía García and Jesús Arauzo},
url = {https://www.degruyter.com/view/journals/ijcre/8/1/article-ijcre.2010.8.1.1924.xml.xml},
doi = {10.2202/1542-6580.1924},
issn = {15426580},
year = {2010},
date = {2010-02-01},
journal = {International Journal of Chemical Reactor Engineering},
volume = {8},
number = {1},
publisher = {Walter de Gruyter GmbH},
abstract = {The present work is focused on the aqueous-phase reforming of ethylene glycol at 500 K. The influence of the system pressure (27 to 36 bar) and the catalyst weight/ethylene glycol flow rate ratio has been studied using a Pt/Al2O3 research catalyst. A comparison of the latter with a Ni/Al coprecipitated catalyst showed a significant influence on hydrogen and alkane selectivities. Copyright textcopyright 2010 The Berkeley Electronic Press.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The present work is focused on the aqueous-phase reforming of ethylene glycol at 500 K. The influence of the system pressure (27 to 36 bar) and the catalyst weight/ethylene glycol flow rate ratio has been studied using a Pt/Al2O3 research catalyst. A comparison of the latter with a Ni/Al coprecipitated catalyst showed a significant influence on hydrogen and alkane selectivities. Copyright textcopyright 2010 The Berkeley Electronic Press.
2009
Artículos de revista
Mendiara, Teresa; Glarborg, Peter
Ammonia chemistry in oxy-fuel combustion of methane Artículo de revista
En: Combustion and Flame, vol. 156, no 10, pp. 1937–1949, 2009, ISSN: 00102180.
@article{Mendiara2009a,
title = {Ammonia chemistry in oxy-fuel combustion of methane},
author = {Teresa Mendiara and Peter Glarborg},
doi = {10.1016/j.combustflame.2009.07.006},
issn = {00102180},
year = {2009},
date = {2009-10-01},
journal = {Combustion and Flame},
volume = {156},
number = {10},
pages = {1937--1949},
publisher = {Elsevier},
abstract = {The oxidation of NH3 during oxy-fuel combustion of methane, i.e., at high [CO2], has been studied in a flow reactor. The experiments covered stoichiometries ranging from fuel rich to very fuel lean and temperatures from 973 to 1773 K. The results have been interpreted in terms of an updated detailed chemical kinetic model. A high CO2 level enhanced formation of NO under reducing conditions while it inhibited NO under stoichiometric and lean conditions. The detailed chemical kinetic model captured fairly well all the experimental trends. According to the present study, the enhanced CO concentrations and alteration in the amount and partitioning of O/H radicals, rather than direct reactions between N-radicals and CO2, are responsible for the effect of a high CO2 concentration on ammonia conversion. When CO2 is present as a bulk gas, formation of NO is facilitated by the increased OH/H ratio. Besides, the high CO levels enhance HNCO formation through NH2 + CO. However, reactions NH2 + O to form HNO and NH2 + H to form NH are inhibited due to the reduced concentration of O and H radicals. Instead reactions of NH2 with species from the hydrocarbon/methylamine pool preserve reactive nitrogen as reduced species. These reactions reduce the NH2 availability to form NO by other pathways like via HNO or NH and increase the probability of forming N2 instead of NO. textcopyright 2009 The Combustion Institute.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The oxidation of NH3 during oxy-fuel combustion of methane, i.e., at high [CO2], has been studied in a flow reactor. The experiments covered stoichiometries ranging from fuel rich to very fuel lean and temperatures from 973 to 1773 K. The results have been interpreted in terms of an updated detailed chemical kinetic model. A high CO2 level enhanced formation of NO under reducing conditions while it inhibited NO under stoichiometric and lean conditions. The detailed chemical kinetic model captured fairly well all the experimental trends. According to the present study, the enhanced CO concentrations and alteration in the amount and partitioning of O/H radicals, rather than direct reactions between N-radicals and CO2, are responsible for the effect of a high CO2 concentration on ammonia conversion. When CO2 is present as a bulk gas, formation of NO is facilitated by the increased OH/H ratio. Besides, the high CO levels enhance HNCO formation through NH2 + CO. However, reactions NH2 + O to form HNO and NH2 + H to form NH are inhibited due to the reduced concentration of O and H radicals. Instead reactions of NH2 with species from the hydrocarbon/methylamine pool preserve reactive nitrogen as reduced species. These reactions reduce the NH2 availability to form NO by other pathways like via HNO or NH and increase the probability of forming N2 instead of NO. textcopyright 2009 The Combustion Institute.
Marín, Fernando; Sánchez, José Luis; Arauzo, Jesús; Fuertes, R; Gonzalo, Alberto
Semichemical pulping of Miscanthus giganteus. Effect of pulping conditions on some pulp and paper properties Artículo de revista
En: Bioresource Technology, vol. 100, no 17, pp. 3933–3940, 2009, ISSN: 09608524.
@article{Marin2009,
title = {Semichemical pulping of Miscanthus giganteus. Effect of pulping conditions on some pulp and paper properties},
author = {Fernando Marín and José Luis Sánchez and Jesús Arauzo and R Fuertes and Alberto Gonzalo},
doi = {10.1016/j.biortech.2009.03.011},
issn = {09608524},
year = {2009},
date = {2009-09-01},
journal = {Bioresource Technology},
volume = {100},
number = {17},
pages = {3933--3940},
publisher = {Elsevier},
abstract = {Miscanthus is an interesting raw material for pulp production, it is a high yield low maintenance plant with a high cellulose and hemicellulose content. Its semichemical pulp can be beneficial in paper for cardboard production process, which nowadays is usually made from secondary fibers, by increasing the mechanical properties of the paper produced. In this study, the influence of the percentage of NaOH used related to the dry Miscanthus weight, digestion time and refining time on some pulp and paper properties have been studied and compared with pulp obtained from commercial fluting paper (CF). Fiber size distribution of the Miscanthus pulp was found to contain a higher fines (less than 0.2 mm) percentage than the CF pulp. Hand-sheets made from Miscanthus pulp showed better mechanical properties than the ones made with the CF pulp. CMT, RCT and CCT indexes were higher when using 100% Miscanthus pulp or mixtures of Miscanthus and CF pulp. The only property which worsened was Gurley porosity. Of the three operational variables changed, refining time exerts the most significant influence on the pulp and paper properties measured. textcopyright 2009 Elsevier Ltd. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Miscanthus is an interesting raw material for pulp production, it is a high yield low maintenance plant with a high cellulose and hemicellulose content. Its semichemical pulp can be beneficial in paper for cardboard production process, which nowadays is usually made from secondary fibers, by increasing the mechanical properties of the paper produced. In this study, the influence of the percentage of NaOH used related to the dry Miscanthus weight, digestion time and refining time on some pulp and paper properties have been studied and compared with pulp obtained from commercial fluting paper (CF). Fiber size distribution of the Miscanthus pulp was found to contain a higher fines (less than 0.2 mm) percentage than the CF pulp. Hand-sheets made from Miscanthus pulp showed better mechanical properties than the ones made with the CF pulp. CMT, RCT and CCT indexes were higher when using 100% Miscanthus pulp or mixtures of Miscanthus and CF pulp. The only property which worsened was Gurley porosity. Of the three operational variables changed, refining time exerts the most significant influence on the pulp and paper properties measured. textcopyright 2009 Elsevier Ltd. All rights reserved.
Manyà, Joan Josep; Antal, Michael Jerry
Review of the apparent molar heat capacities of NaCl(aq), HCl(aq), and NaOH(aq) and their representation using the pitzer model at temperatures from (298.15 to 493.15) K Artículo de revista
En: vol. 54, no 8, pp. 2158–2169, 2009, ISSN: 00219568.
@article{Manya2009,
title = {Review of the apparent molar heat capacities of NaCl(aq), HCl(aq), and NaOH(aq) and their representation using the pitzer model at temperatures from (298.15 to 493.15) K},
author = {Joan Josep Manyà and Michael Jerry Antal},
url = {https://pubs.acs.org/doi/full/10.1021/je8009946},
doi = {10.1021/je8009946},
issn = {00219568},
year = {2009},
date = {2009-08-01},
booktitle = {Journal of Chemical and Engineering Data},
volume = {54},
number = {8},
pages = {2158--2169},
publisher = {American Chemical Society},
abstract = {In this study, a new estimation of the standard state partial molar heat capacity (Cp0) of three binary systems [NaCl(aq), HCl(aq), and NaOH(aq)] for temperatures ranging from (298.15 to 493.15) K is performed. From experimental data (available in the literature to date) corresponding to the apparent molar heat capacities of the above-mentioned electrolytes, a procedure based on the assumption of Pitzer's ion interaction model was applied to calculate these important Cp0 values at a given temperature. Results obtained for each electrolyte (or ion) were correlated as functions of temperature by commonly used polynomial equations. Use of the hydrogen ion convention enabled estimates of the temperature-dependent values of Cp 0 of the individual ions Na+(aq), Cl-(aq), and OH-(aq). When used to calculate the temperature-dependent values of the Gibbs free energy of formation of OH-(aq), the formula for Cp0(T) of OH-(aq) given herein provides good agreement with values derived from independent measurements of the ion constant of water at elevated temperatures. In the specific case of NaCl, a considerable disagreement was observed between the estimations performed using Archer's model (Archer, D. G. J. Phys. Chem. Ref. Data 1992, 793-829) and some experimental data published years later. This fact can be explained, among other factors, by the dependence of the model parameters on the experimental uncertainty and systematic errors, which can be incurred during calorimetric experiments. For this reason, continuous revisions and updating of the proposed correlations are required when new experimental data become available. textcopyright 2009 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this study, a new estimation of the standard state partial molar heat capacity (Cp0) of three binary systems [NaCl(aq), HCl(aq), and NaOH(aq)] for temperatures ranging from (298.15 to 493.15) K is performed. From experimental data (available in the literature to date) corresponding to the apparent molar heat capacities of the above-mentioned electrolytes, a procedure based on the assumption of Pitzer’s ion interaction model was applied to calculate these important Cp0 values at a given temperature. Results obtained for each electrolyte (or ion) were correlated as functions of temperature by commonly used polynomial equations. Use of the hydrogen ion convention enabled estimates of the temperature-dependent values of Cp 0 of the individual ions Na+(aq), Cl-(aq), and OH-(aq). When used to calculate the temperature-dependent values of the Gibbs free energy of formation of OH-(aq), the formula for Cp0(T) of OH-(aq) given herein provides good agreement with values derived from independent measurements of the ion constant of water at elevated temperatures. In the specific case of NaCl, a considerable disagreement was observed between the estimations performed using Archer’s model (Archer, D. G. J. Phys. Chem. Ref. Data 1992, 793-829) and some experimental data published years later. This fact can be explained, among other factors, by the dependence of the model parameters on the experimental uncertainty and systematic errors, which can be incurred during calorimetric experiments. For this reason, continuous revisions and updating of the proposed correlations are required when new experimental data become available. textcopyright 2009 American Chemical Society.
Mendiara, Teresa; Alzueta, María U; Millera, Ángela; Bilbao, Rafael
Acetylene soot reaction with NO in the presence of CO Artículo de revista
En: Journal of Hazardous Materials, vol. 166, no 2-3, pp. 1389–1394, 2009, ISSN: 03043894.
@article{Mendiara2009b,
title = {Acetylene soot reaction with NO in the presence of CO},
author = {Teresa Mendiara and María U Alzueta and Ángela Millera and Rafael Bilbao},
doi = {10.1016/j.jhazmat.2008.12.062},
issn = {03043894},
year = {2009},
date = {2009-07-01},
journal = {Journal of Hazardous Materials},
volume = {166},
number = {2-3},
pages = {1389--1394},
publisher = {Elsevier},
abstract = {The heterogeneous reaction of soot with NO can be considered as a means of reduction of the emissions of both pollutants from combustion systems. In this paper, the influence of the presence of CO in the soot-NO reaction is studied. Soot was obtained by pyrolysis at 1373 K of 5000 ppmv acetylene in nitrogen. The study of the influence of CO on the soot-NO reaction was performed in experiments fixing NO concentration at 900 ppmv and introducing different CO concentrations among 0 and 9900 ppmv. An increase in both the carbon consumption rate and NO reduction by acetylene soot was observed as the concentration of CO increases. These results can be explained by the oxide-stripping reaction, CO + Cf(O) → CO2 + Cf. The direct reaction of CO with NO catalyzed by the carbon surface, CO + NO → CO2 + 1/2 N2 may not be considered in this case the dominant process due to the absence of mineral impurities in the acetylene soot. The influence of CO in the acetylene soot-NO reaction was also tested in the presence of oxygen (250-5000 ppmv). In these conditions and for relatively high CO/O2 ratios, CO seems to also contribute to NO reduction by the previous oxide-stripping reaction. textcopyright 2008 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The heterogeneous reaction of soot with NO can be considered as a means of reduction of the emissions of both pollutants from combustion systems. In this paper, the influence of the presence of CO in the soot-NO reaction is studied. Soot was obtained by pyrolysis at 1373 K of 5000 ppmv acetylene in nitrogen. The study of the influence of CO on the soot-NO reaction was performed in experiments fixing NO concentration at 900 ppmv and introducing different CO concentrations among 0 and 9900 ppmv. An increase in both the carbon consumption rate and NO reduction by acetylene soot was observed as the concentration of CO increases. These results can be explained by the oxide-stripping reaction, CO + Cf(O) → CO2 + Cf. The direct reaction of CO with NO catalyzed by the carbon surface, CO + NO → CO2 + 1/2 N2 may not be considered in this case the dominant process due to the absence of mineral impurities in the acetylene soot. The influence of CO in the acetylene soot-NO reaction was also tested in the presence of oxygen (250-5000 ppmv). In these conditions and for relatively high CO/O2 ratios, CO seems to also contribute to NO reduction by the previous oxide-stripping reaction. textcopyright 2008 Elsevier B.V. All rights reserved.
Mendiara, Teresa; Glarborg, Peter
Reburn chemistry in oxy-fuel combustion of methane Artículo de revista
En: Energy and Fuels, vol. 23, no 7, pp. 3565–3572, 2009, ISSN: 08870624.
@article{Mendiara2009c,
title = {Reburn chemistry in oxy-fuel combustion of methane},
author = {Teresa Mendiara and Peter Glarborg},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ef9001956},
issn = {08870624},
year = {2009},
date = {2009-07-01},
journal = {Energy and Fuels},
volume = {23},
number = {7},
pages = {3565--3572},
publisher = {American Chemical Society},
abstract = {This work deals with the reburn chemistry in oxy-fuel combustion of methane. It was studied experimentally in an atmospheric-pressure flow reactor under diluted conditions in N2 and CO2, respectively. The experiments covered temperatures from 1173 to 1773 K and stoichiometries ranging from fuel-rich to fuel-lean. The results showed similar NO reduction efficiencies in N2 and CO2 under reducing conditions, while under stoichiometric and fuel-lean conditions, the NO reduction obtained in CO2 was higher than that obtained in N2. The temperature at which CO exhibited its maximum concentration coincided with a sharp increase in NO reduction. This temperature was higher in the experiments with CO2 compared to those in N2. The results were interpreted in terms of an updated detailed chemical kinetic model. The effect of CO2 is to increase the OH/H ratio, lower the overall concentration of the O/H radical pool, and increase the availability of CO. Under reducing conditions, the different ways that CO2 interacts with the nitrogen chemistry largely cancel out and the overall impact is small. Under stoichiometric conditions, the NO reduction is enhanced in CO2 because of the suppression of the O/H radical pool, in particular of atomic oxygen. textcopyright 2009 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This work deals with the reburn chemistry in oxy-fuel combustion of methane. It was studied experimentally in an atmospheric-pressure flow reactor under diluted conditions in N2 and CO2, respectively. The experiments covered temperatures from 1173 to 1773 K and stoichiometries ranging from fuel-rich to fuel-lean. The results showed similar NO reduction efficiencies in N2 and CO2 under reducing conditions, while under stoichiometric and fuel-lean conditions, the NO reduction obtained in CO2 was higher than that obtained in N2. The temperature at which CO exhibited its maximum concentration coincided with a sharp increase in NO reduction. This temperature was higher in the experiments with CO2 compared to those in N2. The results were interpreted in terms of an updated detailed chemical kinetic model. The effect of CO2 is to increase the OH/H ratio, lower the overall concentration of the O/H radical pool, and increase the availability of CO. Under reducing conditions, the different ways that CO2 interacts with the nitrogen chemistry largely cancel out and the overall impact is small. Under stoichiometric conditions, the NO reduction is enhanced in CO2 because of the suppression of the O/H radical pool, in particular of atomic oxygen. textcopyright 2009 American Chemical Society.
Aznar, María; Anselmo, Marta San; Manyà, Joan Josep; Murillo, María Benita
Experimental study examining the evolution of nitrogen compounds during the gasification of dried sewage sludge Artículo de revista
En: Energy and Fuels, vol. 23, no 6, pp. 3236–3245, 2009, ISSN: 08870624.
@article{Aznar2009,
title = {Experimental study examining the evolution of nitrogen compounds during the gasification of dried sewage sludge},
author = {María Aznar and Marta San Anselmo and Joan Josep Manyà and María Benita Murillo},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ef801108s},
issn = {08870624},
year = {2009},
date = {2009-06-01},
journal = {Energy and Fuels},
volume = {23},
number = {6},
pages = {3236--3245},
publisher = {American Chemical Society},
abstract = {Gasification of dried sewage sludge, which contains a high percentage of nitrogen, was experimentally studied to determine the effects of some operational parameters, such as freeboard temperature and equivalence ratio, on the partitioning of the fuel nitrogen among nitrogenous species. Experiments were performed using a bench-scale fluidized-bed gasifier and according to a well-specified procedure implemented to recover and quantify the nitrogen compounds. A mixture of argon and oxygen in similar proportions to air was used as a gasification agent in order to correctly quantify the N2 produced in the gasification process in an experimental way. Important findings of this research include the following: applying the analytical procedure developed in this work, a reasonably good inventory of nitrogen in the gasification products was obtained (mass balance closures near to 100%); most of the nitrogen goes to form gaseous products, N2 being the main gaseous nitrogen-containing product obtained; concentrations of N2, NH3, and N-tar in the producer gas strongly depend on the freeboard temperature, an increase of which causes an important decrease of both NH 3 and N-tar contents and a substantial increase of the N2 amount. textcopyright 2009 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Gasification of dried sewage sludge, which contains a high percentage of nitrogen, was experimentally studied to determine the effects of some operational parameters, such as freeboard temperature and equivalence ratio, on the partitioning of the fuel nitrogen among nitrogenous species. Experiments were performed using a bench-scale fluidized-bed gasifier and according to a well-specified procedure implemented to recover and quantify the nitrogen compounds. A mixture of argon and oxygen in similar proportions to air was used as a gasification agent in order to correctly quantify the N2 produced in the gasification process in an experimental way. Important findings of this research include the following: applying the analytical procedure developed in this work, a reasonably good inventory of nitrogen in the gasification products was obtained (mass balance closures near to 100%); most of the nitrogen goes to form gaseous products, N2 being the main gaseous nitrogen-containing product obtained; concentrations of N2, NH3, and N-tar in the producer gas strongly depend on the freeboard temperature, an increase of which causes an important decrease of both NH 3 and N-tar contents and a substantial increase of the N2 amount. textcopyright 2009 American Chemical Society.
Fonts, Isabel; Azuara, Manuel; Lázaro, Luisa; Gea, Gloria; Murillo, María Benita
Gas chromatography study of sewage sludge pyrolysis liquids obtained at different operational conditions in a fluidized bed Artículo de revista
En: Industrial and Engineering Chemistry Research, vol. 48, no 12, pp. 5907–5915, 2009, ISSN: 08885885.
@article{Fonts2009b,
title = {Gas chromatography study of sewage sludge pyrolysis liquids obtained at different operational conditions in a fluidized bed},
author = {Isabel Fonts and Manuel Azuara and Luisa Lázaro and Gloria Gea and María Benita Murillo},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ie900421a},
issn = {08885885},
year = {2009},
date = {2009-06-01},
journal = {Industrial and Engineering Chemistry Research},
volume = {48},
number = {12},
pages = {5907--5915},
publisher = {American Chemical Society},
abstract = {Sewage sludge was pyrolyzed in a fluidized bed under different operational conditions with the aim of studying the influence of some operational conditions on the composition of the liquid product. These operational conditions were bed temperature (450-650 ?C), inlet nitrogen rate (nitrogen flow per bed surface unit 0.057-0.090 m s-1), and solid feed rate per bed volumetric unit (0.169-0.338 kg s-1 m-3). The composition of the pyrolysis liquids obtained was analyzed by means of GC-MS and GC-FID. Different families of compounds appeared in the liquid samples obtained under the different conditions studied: aliphatic, aromatic, and polycyclic aromatic hydrocarbons; oxygen-containing aliphatic and aromatic compounds; nitrogencontaining aliphatic and aromatic compounds; steroids; chlorine-containing compounds; and sulfur-containing compounds. The composition of the liquids varied qualitatively with the temperature and quantitatively with the three operational parameters studied, with the temperature being the most influential variable. The liquids obtained at 450 ?C contained oxygen-containing aliphatic compounds > steroids > aliphatic hydrocarbons > nitrogen-containing aliphatic compounds. The compounds found in the liquids obtained at 550 ?C were quite similar to those obtained at 450 ?C, although their proportions were different: steroids > aliphatic hydrocarbons > oxygen-containing aliphatic compounds > nitrogen-containing aromatic compounds. The composition of the liquids obtained at 650 ?C varied considerably, and the most abundant compound groups were nitrogencontaining aromatic compounds > polycyclic aromatic hydrocarbons > aromatic hydrocarbons. textcopyright2009 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Sewage sludge was pyrolyzed in a fluidized bed under different operational conditions with the aim of studying the influence of some operational conditions on the composition of the liquid product. These operational conditions were bed temperature (450-650 ?C), inlet nitrogen rate (nitrogen flow per bed surface unit 0.057-0.090 m s-1), and solid feed rate per bed volumetric unit (0.169-0.338 kg s-1 m-3). The composition of the pyrolysis liquids obtained was analyzed by means of GC-MS and GC-FID. Different families of compounds appeared in the liquid samples obtained under the different conditions studied: aliphatic, aromatic, and polycyclic aromatic hydrocarbons; oxygen-containing aliphatic and aromatic compounds; nitrogencontaining aliphatic and aromatic compounds; steroids; chlorine-containing compounds; and sulfur-containing compounds. The composition of the liquids varied qualitatively with the temperature and quantitatively with the three operational parameters studied, with the temperature being the most influential variable. The liquids obtained at 450 ?C contained oxygen-containing aliphatic compounds > steroids > aliphatic hydrocarbons > nitrogen-containing aliphatic compounds. The compounds found in the liquids obtained at 550 ?C were quite similar to those obtained at 450 ?C, although their proportions were different: steroids > aliphatic hydrocarbons > oxygen-containing aliphatic compounds > nitrogen-containing aromatic compounds. The composition of the liquids obtained at 650 ?C varied considerably, and the most abundant compound groups were nitrogencontaining aromatic compounds > polycyclic aromatic hydrocarbons > aromatic hydrocarbons. textcopyright2009 American Chemical Society.
Bimbela, Fernando; Oliva, Miriam; Ruiz, Joaquín; García, Lucía; Arauzo, Jesús
Catalytic steam reforming of model compounds of biomass pyrolysis liquids in fixed bed: Acetol and n-butanol Artículo de revista
En: Journal of Analytical and Applied Pyrolysis, vol. 85, no 1-2, pp. 204–213, 2009, ISSN: 01652370.
@article{Bimbela2009,
title = {Catalytic steam reforming of model compounds of biomass pyrolysis liquids in fixed bed: Acetol and n-butanol},
author = {Fernando Bimbela and Miriam Oliva and Joaquín Ruiz and Lucía García and Jesús Arauzo},
doi = {10.1016/j.jaap.2008.11.033},
issn = {01652370},
year = {2009},
date = {2009-05-01},
journal = {Journal of Analytical and Applied Pyrolysis},
volume = {85},
number = {1-2},
pages = {204--213},
publisher = {Elsevier},
abstract = {Acetol (hydroxyacetone) and 1-butanol, model compounds of the aqueous fraction of biomass pyrolysis liquids (bio-oil), have been catalytically steam reformed in a microscale fixed-bed facility. Three Ni coprecipitated catalysts, with varying nickel content (23, 28 and 33% expressed as a Ni/(Ni + Al) relative atomic% of nickel), have been tested. Several parameters have been analysed: the reaction temperature, the catalyst weight/organic flow rate (W/m) ratio, and the effect of the nickel content. The temperatures studied were 550, 650 and 750 °C. At the experimental conditions tested, an increase in the reaction temperature resulted in greater carbon conversion to product gases in non-catalytic and catalytic steam reforming for both model compounds. The nickel content of the catalyst has a significant influence on the steam reforming of oxygenates. The best performance, in terms of H2 yield, is obtained with the catalyst with 28% Ni content. For experiments carried out at space velocities around 30,000 h-1 during 2 h, acetol showed a slightly higher carbon conversion to gas than butanol, though butanol depicted a more constant evolution of carbon conversion throughout. textcopyright 2008 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Acetol (hydroxyacetone) and 1-butanol, model compounds of the aqueous fraction of biomass pyrolysis liquids (bio-oil), have been catalytically steam reformed in a microscale fixed-bed facility. Three Ni coprecipitated catalysts, with varying nickel content (23, 28 and 33% expressed as a Ni/(Ni + Al) relative atomic% of nickel), have been tested. Several parameters have been analysed: the reaction temperature, the catalyst weight/organic flow rate (W/m) ratio, and the effect of the nickel content. The temperatures studied were 550, 650 and 750 °C. At the experimental conditions tested, an increase in the reaction temperature resulted in greater carbon conversion to product gases in non-catalytic and catalytic steam reforming for both model compounds. The nickel content of the catalyst has a significant influence on the steam reforming of oxygenates. The best performance, in terms of H2 yield, is obtained with the catalyst with 28% Ni content. For experiments carried out at space velocities around 30,000 h-1 during 2 h, acetol showed a slightly higher carbon conversion to gas than butanol, though butanol depicted a more constant evolution of carbon conversion throughout. textcopyright 2008 Elsevier B.V. All rights reserved.
Fonts, Isabel; Azuara, Manuel; Gea, Gloria; Murillo, María Benita
Study of the pyrolysis liquids obtained from different sewage sludge Artículo de revista
En: Journal of Analytical and Applied Pyrolysis, vol. 85, no 1-2, pp. 184–191, 2009, ISSN: 01652370.
@article{Fonts2009c,
title = {Study of the pyrolysis liquids obtained from different sewage sludge},
author = {Isabel Fonts and Manuel Azuara and Gloria Gea and María Benita Murillo},
doi = {10.1016/j.jaap.2008.11.003},
issn = {01652370},
year = {2009},
date = {2009-05-01},
journal = {Journal of Analytical and Applied Pyrolysis},
volume = {85},
number = {1-2},
pages = {184--191},
publisher = {Elsevier},
abstract = {Pyrolysis of sewage sludge in fluidized bed to produce bio-oil is under study as a useful way to valorise this waste. Sewage sludge is the waste produced in the wastewater treatment plants. Its composition may change due to the origin and to the non-standardized treatments in the wastewater treatment plants. The pyrolysis of three samples of anaerobically digested sewage sludge obtained from three different urban wastewater treatment plants was studied in this work. The organic and inorganic matter composition, and the volatile and ash content of these sewage sludge samples were different. The influence of these parameters on the pyrolysis product distribution and on some characteristics of these products was studied. It was determined that the ash content of the raw material had an enormous influence on the sewage sludge pyrolysis. An increase in the ash content of the sewage sludge caused an increase in the gas yield and a decrease in the liquid and the solid yield with the operational conditions studied. The increase of the volatile content of the sewage sludge samples caused an increase in the liquid yield. The H2 proportion was the most influenced non-condensable gas. It increased significantly with the ash content. The viscosity of the pyrolysis oils decreased when the ash content augmented. On the other hand, the water content depended on the organic composition of the sewage sludge samples. The chemical composition of the pyrolysis oils was also affected by the sewage sludge ash content above all the proportion of polyaromatic hydrocarbons and nitrogen-containing aromatic compounds. These compound groups increased with the augment of the sewage sludge ash content. The oxygen-containing aliphatic compounds and the steroids decreased with the ash content, although its proportion in the sewage sludge liquid was also influenced by the organic matter composition of the sewage sludge samples. textcopyright 2008 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Pyrolysis of sewage sludge in fluidized bed to produce bio-oil is under study as a useful way to valorise this waste. Sewage sludge is the waste produced in the wastewater treatment plants. Its composition may change due to the origin and to the non-standardized treatments in the wastewater treatment plants. The pyrolysis of three samples of anaerobically digested sewage sludge obtained from three different urban wastewater treatment plants was studied in this work. The organic and inorganic matter composition, and the volatile and ash content of these sewage sludge samples were different. The influence of these parameters on the pyrolysis product distribution and on some characteristics of these products was studied. It was determined that the ash content of the raw material had an enormous influence on the sewage sludge pyrolysis. An increase in the ash content of the sewage sludge caused an increase in the gas yield and a decrease in the liquid and the solid yield with the operational conditions studied. The increase of the volatile content of the sewage sludge samples caused an increase in the liquid yield. The H2 proportion was the most influenced non-condensable gas. It increased significantly with the ash content. The viscosity of the pyrolysis oils decreased when the ash content augmented. On the other hand, the water content depended on the organic composition of the sewage sludge samples. The chemical composition of the pyrolysis oils was also affected by the sewage sludge ash content above all the proportion of polyaromatic hydrocarbons and nitrogen-containing aromatic compounds. These compound groups increased with the augment of the sewage sludge ash content. The oxygen-containing aliphatic compounds and the steroids decreased with the ash content, although its proportion in the sewage sludge liquid was also influenced by the organic matter composition of the sewage sludge samples. textcopyright 2008 Elsevier B.V. All rights reserved.
Medrano, José A; Oliva, Miriam; Ruiz, Joaquín; García, Lucía; Arauzo, Jesús
Catalytic steam reforming of model compounds of biomass pyrolysis liquids in fluidized bed reactor with modified Ni/Al catalysts Artículo de revista
En: Journal of Analytical and Applied Pyrolysis, vol. 85, no 1-2, pp. 214–225, 2009, ISSN: 01652370.
@article{Medrano2009,
title = {Catalytic steam reforming of model compounds of biomass pyrolysis liquids in fluidized bed reactor with modified Ni/Al catalysts},
author = {José A Medrano and Miriam Oliva and Joaquín Ruiz and Lucía García and Jesús Arauzo},
doi = {10.1016/j.jaap.2008.11.025},
issn = {01652370},
year = {2009},
date = {2009-05-01},
journal = {Journal of Analytical and Applied Pyrolysis},
volume = {85},
number = {1-2},
pages = {214--225},
publisher = {Elsevier},
abstract = {Catalytic steam reforming of acetic acid and hydroxyacetone (acetol) as model compounds of the aqueous fraction of bio-oil (biomass derived pyrolysis liquids) was studied in fluidized bed reactor over Ni/Al catalysts modified with calcium or magnesium. Attrition tests showed that the use of small quantities of these promoters improved the mechanical strength of the reforming catalyst. An optimum Ca/Al molar ratio of 0.12 and a Mg/Al molar ratio of 0.26 leaded to attrition rates of 0.22 and 0.27 wt%/h, respectively. Steam reforming experiments were performed at 650 °C and a steam to carbon molar ratio (S/C) of 5.58. The promoted catalysts showed different acetic acid steam reforming activities depending on the Ca/Al or Mg/Al molar ratios. Magnesium modified catalysts with a Mg/Al molar ratios of 0.26 and 0.50 showed good performances with almost no activity loss with time in contrast to the calcium modified catalysts that showed higher CO and CH4 yields. The addition of calcium generated a NiO phase with less interaction with the support. The highest H2 yield and carbon conversion in acetic steam reforming were obtained by a magnesium promoted catalyst with a Mg/Al ratio of 0.26, while the nonpromoted Ni/Al catalyst showed the best performance in acetol steam reforming. Then, the nature of the organic compound influenced the performance of the different catalysts. textcopyright 2008 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Catalytic steam reforming of acetic acid and hydroxyacetone (acetol) as model compounds of the aqueous fraction of bio-oil (biomass derived pyrolysis liquids) was studied in fluidized bed reactor over Ni/Al catalysts modified with calcium or magnesium. Attrition tests showed that the use of small quantities of these promoters improved the mechanical strength of the reforming catalyst. An optimum Ca/Al molar ratio of 0.12 and a Mg/Al molar ratio of 0.26 leaded to attrition rates of 0.22 and 0.27 wt%/h, respectively. Steam reforming experiments were performed at 650 °C and a steam to carbon molar ratio (S/C) of 5.58. The promoted catalysts showed different acetic acid steam reforming activities depending on the Ca/Al or Mg/Al molar ratios. Magnesium modified catalysts with a Mg/Al molar ratios of 0.26 and 0.50 showed good performances with almost no activity loss with time in contrast to the calcium modified catalysts that showed higher CO and CH4 yields. The addition of calcium generated a NiO phase with less interaction with the support. The highest H2 yield and carbon conversion in acetic steam reforming were obtained by a magnesium promoted catalyst with a Mg/Al ratio of 0.26, while the nonpromoted Ni/Al catalyst showed the best performance in acetol steam reforming. Then, the nature of the organic compound influenced the performance of the different catalysts. textcopyright 2008 Elsevier B.V. All rights reserved.
Esarte, Claudia; Millera, Ángela; Bilbao, Rafael; Alzueta, María U
Gas and soot products formed in the pyrolysis of acetylene-ethanol blends under flow reactor conditions Artículo de revista
En: Fuel Processing Technology, vol. 90, no 4, pp. 496–503, 2009, ISSN: 03783820.
@article{Esarte2009,
title = {Gas and soot products formed in the pyrolysis of acetylene-ethanol blends under flow reactor conditions},
author = {Claudia Esarte and Ángela Millera and Rafael Bilbao and María U Alzueta},
doi = {10.1016/j.fuproc.2009.01.011},
issn = {03783820},
year = {2009},
date = {2009-04-01},
journal = {Fuel Processing Technology},
volume = {90},
number = {4},
pages = {496--503},
publisher = {Elsevier},
abstract = {The present paper reports a laboratory study on the pyrolysis of different blends containing acetylene, known as an important soot precursor, and ethanol, regarded as an appropriate additive to conventional fuels aiming to diminish the emission of pollutants coming from combustion processes. Pyrolysis experiments of acetylene-ethanol blends, for a total initial concentration of reactants of 50,000 ppm, with variable volume percentages of ethanol between 0 and 40% with respect to the total concentration of reactants, have been carried out in a quartz flow reactor working in a temperature range of 975-1475 K. The influence of both pyrolysis temperature and ethanol concentration in the blend on the gas and solid products has been evaluated. As the reaction temperature is increased, the soot production is higher and yield to carbonaceous gas products decreases. It is noticed that the presence of ethanol inhibits the production of soot and the diminution of soot formation does not present a linear dependency with the ethanol concentration; the influence is comparatively stronger when adding small amounts of ethanol. The analysis of the gas products reveals that increasing the ethanol percentage in the blend causes an increase of the concentration of some intermediates such as ethylene, ethane, methane or benzene, pointing to a variation of the reacting species which could prevent soot formation. A literature detailed gas phase kinetic mechanism including reaction subsets for acetylene and ethanol conversion has been used to simulate the experimental results. This theoretical study has been carried out with the purpose of analyzing the trends of the evolution of gas products and getting a better understanding of the gas phase processes involved in the pyrolysis of the different blends, although soot formation is not included. textcopyright 2009 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The present paper reports a laboratory study on the pyrolysis of different blends containing acetylene, known as an important soot precursor, and ethanol, regarded as an appropriate additive to conventional fuels aiming to diminish the emission of pollutants coming from combustion processes. Pyrolysis experiments of acetylene-ethanol blends, for a total initial concentration of reactants of 50,000 ppm, with variable volume percentages of ethanol between 0 and 40% with respect to the total concentration of reactants, have been carried out in a quartz flow reactor working in a temperature range of 975-1475 K. The influence of both pyrolysis temperature and ethanol concentration in the blend on the gas and solid products has been evaluated. As the reaction temperature is increased, the soot production is higher and yield to carbonaceous gas products decreases. It is noticed that the presence of ethanol inhibits the production of soot and the diminution of soot formation does not present a linear dependency with the ethanol concentration; the influence is comparatively stronger when adding small amounts of ethanol. The analysis of the gas products reveals that increasing the ethanol percentage in the blend causes an increase of the concentration of some intermediates such as ethylene, ethane, methane or benzene, pointing to a variation of the reacting species which could prevent soot formation. A literature detailed gas phase kinetic mechanism including reaction subsets for acetylene and ethanol conversion has been used to simulate the experimental results. This theoretical study has been carried out with the purpose of analyzing the trends of the evolution of gas products and getting a better understanding of the gas phase processes involved in the pyrolysis of the different blends, although soot formation is not included. textcopyright 2009 Elsevier B.V. All rights reserved.
Ábrego, Javier; Arauzo, Jesús; Sánchez, José Luis; Gonzalo, Alberto; Cordero, Tomás; Rodríguez-Mirasol, José
Structural changes of sewage sludge char during fixed-bed pyrolysis Artículo de revista
En: Industrial and Engineering Chemistry Research, vol. 48, no 6, pp. 3211–3221, 2009, ISSN: 08885885.
@article{Abrego2009,
title = {Structural changes of sewage sludge char during fixed-bed pyrolysis},
author = {Javier Ábrego and Jesús Arauzo and José Luis Sánchez and Alberto Gonzalo and Tomás Cordero and José Rodríguez-Mirasol},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ie801366t},
issn = {08885885},
year = {2009},
date = {2009-03-01},
journal = {Industrial and Engineering Chemistry Research},
volume = {48},
number = {6},
pages = {3211--3221},
publisher = {American Chemical Society},
abstract = {Undigested dried sewage sludge from a wastewater treatment plant was pyrolyzed at temperatures between 300 and 900 °C, with an additional hold time at the highest temperature. A fixed-bed reactor was used with a heating rate of 20 °C/min under an atmosphere of nitrogen. Pyrolysis product distribution, FTIR, XRD, BET, SEM, and ultimate and proximate analyses were used to gain a better understanding of the structural changes occurring during pyrolysis. At low to medium pyrolysis temperatures, major mass loss occurs, and most of the gaseous and liquid products are released with little porous development, whereas at temperatures between 700 and 900 °C, structural changes seem to be triggered by calcium carbonate decomposition. This leads to a second stage of gas evolution, as CaO promotes gasification of the char in the presence of iron sulfides. The subsequent release of CO runs parallel with an increase in the BET surface area. In addition, the aromatic character of the char increases with temperature, and nanotube-like tubular structures can be detected by SEM. textcopyright 2009 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Undigested dried sewage sludge from a wastewater treatment plant was pyrolyzed at temperatures between 300 and 900 °C, with an additional hold time at the highest temperature. A fixed-bed reactor was used with a heating rate of 20 °C/min under an atmosphere of nitrogen. Pyrolysis product distribution, FTIR, XRD, BET, SEM, and ultimate and proximate analyses were used to gain a better understanding of the structural changes occurring during pyrolysis. At low to medium pyrolysis temperatures, major mass loss occurs, and most of the gaseous and liquid products are released with little porous development, whereas at temperatures between 700 and 900 °C, structural changes seem to be triggered by calcium carbonate decomposition. This leads to a second stage of gas evolution, as CaO promotes gasification of the char in the presence of iron sulfides. The subsequent release of CO runs parallel with an increase in the BET surface area. In addition, the aromatic character of the char increases with temperature, and nanotube-like tubular structures can be detected by SEM. textcopyright 2009 American Chemical Society.
Fonts, Isabel; Juan, Alfonso; Gea, Gloria; Murillo, María Benita; Arauzo, Jesús
Sewage sludge pyrolysis in a fluidized bed, 2: Influence of operating conditions on some physicochemical properties of the liquid product Artículo de revista
En: Industrial and Engineering Chemistry Research, vol. 48, no 4, pp. 2179–2187, 2009, ISSN: 08885885.
@article{Fonts2009a,
title = {Sewage sludge pyrolysis in a fluidized bed, 2: Influence of operating conditions on some physicochemical properties of the liquid product},
author = {Isabel Fonts and Alfonso Juan and Gloria Gea and María Benita Murillo and Jesús Arauzo},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ie801448g},
issn = {08885885},
year = {2009},
date = {2009-02-01},
journal = {Industrial and Engineering Chemistry Research},
volume = {48},
number = {4},
pages = {2179--2187},
publisher = {American Chemical Society},
abstract = {Sewage sludge was pyrolyzed at different operating conditions with the aim of producing pyrolysis liquid. In this work, the influence of some operating conditions was studied in relation to some liquid properties such as homogeneity (phase separation), solids content, water content, and high heating value. The operating variables studied were bed temperature (450-650°C), inlet nitrogen rate (0.057-0.090 m s-1), and solid feed rate per volumetric unit (0.169-0.338 kg s-1 m-3). Phase separation appeared in the samples obtained at almost all operating conditions studied, and it was different depending on the operating temperature and the sample of sewage sludge. The experimental methodology for analyzing the quantitative properties of the pyrolysis liquid under study was based on experimental design techniques. These liquid properties were influenced in different ways by the three studied operating conditions, but above all by the temperature, the inlet nitrogen rate, and also the sample of sewage sludge. Based on the experimental data, empirical models were built to describe the influence of the operating conditions on the liquid properties. Additionally, using these empirical models, operating conditions (within the intervals under study) that allow a high liquid yield and a liquid product with desirable values of the studied properties to be obtained were predicted theoretically. textcopyright 2009 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Sewage sludge was pyrolyzed at different operating conditions with the aim of producing pyrolysis liquid. In this work, the influence of some operating conditions was studied in relation to some liquid properties such as homogeneity (phase separation), solids content, water content, and high heating value. The operating variables studied were bed temperature (450-650°C), inlet nitrogen rate (0.057-0.090 m s-1), and solid feed rate per volumetric unit (0.169-0.338 kg s-1 m-3). Phase separation appeared in the samples obtained at almost all operating conditions studied, and it was different depending on the operating temperature and the sample of sewage sludge. The experimental methodology for analyzing the quantitative properties of the pyrolysis liquid under study was based on experimental design techniques. These liquid properties were influenced in different ways by the three studied operating conditions, but above all by the temperature, the inlet nitrogen rate, and also the sample of sewage sludge. Based on the experimental data, empirical models were built to describe the influence of the operating conditions on the liquid properties. Additionally, using these empirical models, operating conditions (within the intervals under study) that allow a high liquid yield and a liquid product with desirable values of the studied properties to be obtained were predicted theoretically. textcopyright 2009 American Chemical Society.
Casajus, C; Ábrego, Javier; Marias, Frederic; Vaxelaire, J; Sánchez, José Luis; Gonzalo, Alberto
Product distribution and kinetic scheme for the fixed bed thermal decomposition of sewage sludge Artículo de revista
En: Chemical Engineering Journal, vol. 145, no 3, pp. 412–419, 2009, ISSN: 13858947.
@article{Casajus2009,
title = {Product distribution and kinetic scheme for the fixed bed thermal decomposition of sewage sludge},
author = {C Casajus and Javier Ábrego and Frederic Marias and J Vaxelaire and José Luis Sánchez and Alberto Gonzalo},
doi = {10.1016/j.cej.2008.08.033},
issn = {13858947},
year = {2009},
date = {2009-01-01},
journal = {Chemical Engineering Journal},
volume = {145},
number = {3},
pages = {412--419},
publisher = {Elsevier},
abstract = {In this paper, a new kinetic model for the thermal decomposition of dry sewage sludge was determined. In order to achieve this main objective, various experiments were carried out to collect enough information for the estimation of the different numerical parameters of the model. These experiments include both results from a fixed bed pyrolysis installation and a thermogravimetric analysis device. The experiments allowed for the detailed monitoring of the dynamical evolution of the mass of the sample under investigation, together with the cumulative amounts of tars and permanent gases produced during thermal decomposition of sewage sludge at low heating rates (5-20 °C/min). Solid mass loss during the pyrolysis shows two regions, between 150 °C and 600 °C, where most of the tar is depleted from the solid and non-condensible gases are formed, and a second one between 600 °C and 900 °C where mainly only non-condensible gases are produced. The solid fraction accounted for about 50% of the initial weight, tar around 30% and gases the remaining 20%. Regarding the formation of non-condensible gases from low temperature, a new kinetic scheme was proposed involving an initial decomposition step of the sludge yielding tar and gases as gas phase products and a solid intermediate compound which decomposes at higher temperatures, giving the char fraction and more non-condensible gases. The comparison between the numerical prediction and the experimental results was excellent. textcopyright 2008 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In this paper, a new kinetic model for the thermal decomposition of dry sewage sludge was determined. In order to achieve this main objective, various experiments were carried out to collect enough information for the estimation of the different numerical parameters of the model. These experiments include both results from a fixed bed pyrolysis installation and a thermogravimetric analysis device. The experiments allowed for the detailed monitoring of the dynamical evolution of the mass of the sample under investigation, together with the cumulative amounts of tars and permanent gases produced during thermal decomposition of sewage sludge at low heating rates (5-20 °C/min). Solid mass loss during the pyrolysis shows two regions, between 150 °C and 600 °C, where most of the tar is depleted from the solid and non-condensible gases are formed, and a second one between 600 °C and 900 °C where mainly only non-condensible gases are produced. The solid fraction accounted for about 50% of the initial weight, tar around 30% and gases the remaining 20%. Regarding the formation of non-condensible gases from low temperature, a new kinetic scheme was proposed involving an initial decomposition step of the sludge yielding tar and gases as gas phase products and a solid intermediate compound which decomposes at higher temperatures, giving the char fraction and more non-condensible gases. The comparison between the numerical prediction and the experimental results was excellent. textcopyright 2008 Elsevier B.V. All rights reserved.
Giménez-López, Jorge; Rasmussen, Christian Lund; Alzueta, María U; Gao, Yide; Marshall, Paul; Glarborg, Peter
Experimental and kinetic modeling study of C2H4 oxidation at high pressure Artículo de revista
En: Proceedings of the Combustion Institute, vol. 32 I, no 1, pp. 367–375, 2009, ISSN: 15407489.
@article{Lopez2009,
title = {Experimental and kinetic modeling study of C2H4 oxidation at high pressure},
author = {Jorge Giménez-López and Christian Lund Rasmussen and María U Alzueta and Yide Gao and Paul Marshall and Peter Glarborg},
doi = {10.1016/j.proci.2008.06.188},
issn = {15407489},
year = {2009},
date = {2009-01-01},
journal = {Proceedings of the Combustion Institute},
volume = {32 I},
number = {1},
pages = {367--375},
publisher = {Elsevier Ltd},
abstract = {A detailed chemical kinetic model for oxidation of C2H 4 in the intermediate temperature range and high pressure has been developed and validated experimentally. New ab initio calculations and RRKM analysis of the important C2H3 + O2 reaction was used to obtain rate coefficients over a wide range of conditions (0.003-100 bar, 200-3000 K). The results indicate that at 60 bar and medium temperatures vinyl peroxide, rather than CH2O and HCO, is the dominant product. The experiments, involving C2H4/O2 mixtures diluted in N2, were carried out in a high pressure flow reactor at 600-900 K and 60 bar, varying the reaction stoichiometry from very lean to fuel-rich conditions. Model predictions are generally satisfactory. The governing reaction mechanisms are outlined based on calculations with the kinetic model. Under the investigated conditions the oxidation pathways for C2H4 are more complex than those prevailing at higher temperatures and lower pressures. The major differences are the importance of the hydroxyethyl (CH2CH2OH) and 2-hydroperoxyethyl (CH2CH2OOH) radicals, formed from addition of OH and HO2 to C2H4, and vinyl peroxide, formed from C2H3 + O2. Hydroxyethyl is oxidized through the peroxide HOCH2CH2OO (lean conditions) or through ethenol (low O2 concentration), while 2-hydroperoxyethyl is converted through oxirane. textcopyright 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A detailed chemical kinetic model for oxidation of C2H 4 in the intermediate temperature range and high pressure has been developed and validated experimentally. New ab initio calculations and RRKM analysis of the important C2H3 + O2 reaction was used to obtain rate coefficients over a wide range of conditions (0.003-100 bar, 200-3000 K). The results indicate that at 60 bar and medium temperatures vinyl peroxide, rather than CH2O and HCO, is the dominant product. The experiments, involving C2H4/O2 mixtures diluted in N2, were carried out in a high pressure flow reactor at 600-900 K and 60 bar, varying the reaction stoichiometry from very lean to fuel-rich conditions. Model predictions are generally satisfactory. The governing reaction mechanisms are outlined based on calculations with the kinetic model. Under the investigated conditions the oxidation pathways for C2H4 are more complex than those prevailing at higher temperatures and lower pressures. The major differences are the importance of the hydroxyethyl (CH2CH2OH) and 2-hydroperoxyethyl (CH2CH2OOH) radicals, formed from addition of OH and HO2 to C2H4, and vinyl peroxide, formed from C2H3 + O2. Hydroxyethyl is oxidized through the peroxide HOCH2CH2OO (lean conditions) or through ethenol (low O2 concentration), while 2-hydroperoxyethyl is converted through oxirane. textcopyright 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
2008
Artículos de revista
Abián, María; Esarte, Claudia; Millera, Ángela; Bilbao, Rafael; Alzueta, María U
Oxidation of acetylene-ethanol mixtures and their interaction with NO Artículo de revista
En: Energy and Fuels, vol. 22, no 6, pp. 3814–3823, 2008, ISSN: 08870624.
@article{Abian2008,
title = {Oxidation of acetylene-ethanol mixtures and their interaction with NO},
author = {María Abián and Claudia Esarte and Ángela Millera and Rafael Bilbao and María U Alzueta},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ef800550k},
issn = {08870624},
year = {2008},
date = {2008-11-01},
journal = {Energy and Fuels},
volume = {22},
number = {6},
pages = {3814--3823},
publisher = {American Chemical Society},
abstract = {An experimental and theoretical study of the oxidation of acetylene-ethanol mixtures in the absence and presence of NO has been carried out. The experiments were conducted in an isothermal quartz flow reactor at atmospheric pressure in the 775-1375 K temperature range. The influence of the temperature, stoichiometry (by varying the O2 concentration for given C2H2 and C2H5OH initial concentrations), presence of different amounts of ethanol added to acetylene, and presence of NO on the concentrations of C2H2, C2H5OH, CO, CO2, NO, and HCN has been analyzed. The gas-phase kinetic mechanism used for calculations was that developed by Alzueta et al. (Alzueta, M. U.; Borruey, M.; Callejas, A.; Millera, A.; Bilbao, R. Combust. Flame 2008, 152, 377-386) for acetylene conversion, on the basis of a previous work by Skjoth-Rasmussen et al. (Skjøth-Rasmussen, M. S.; Glarborg, P.; Østberg, M.; Johannessen, J. T.; Livbjerg, H.; Jensen, A. D.; Christensen, T. S. Combust. Flame 2004, 136, 91-128), with reactions added from the ethanol oxidation mechanism of Alzueta and Hernández (Alzueta, M. U.; Hernández, J. M. Energy Fuels 2002, 16, 166-171), as well as reactions from the mechanism developed by Glarborg et al. (Glarborg, P.; Alzueta, M. U.; Dam-Johansen, K.; Miller, J. A. Combust. Flame 1998, 115, 1-27) to describe the interactions among C1/C2 hydrocarbons and nitric oxide. The experimental results show that the ethanol presence significantly modifies the acetylene conversion regime, inhibiting soot formation. An increase of the oxygen level and temperature favor acetylene conversion. The presence of NO results in some differences in relation to the oxidation regimes of the acetylene-ethanol blends. The reduction of NO by the mixture is favored at the highest temperatures of the considered range, above 1275 K, and for moderately fuel-ricb conditions ($łambda$ = 0.7). In general, the kinetic model satisfactorily simulates the experimental trends. Model predictions indicate that, under the conditions of this study, HCCO + NO is the most important reaction in reducing NO. Moreover, the ethanol presence slightly inhibits the NO reduction in relation to the oxidation of pure acetylene. textcopyright 2008 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
An experimental and theoretical study of the oxidation of acetylene-ethanol mixtures in the absence and presence of NO has been carried out. The experiments were conducted in an isothermal quartz flow reactor at atmospheric pressure in the 775-1375 K temperature range. The influence of the temperature, stoichiometry (by varying the O2 concentration for given C2H2 and C2H5OH initial concentrations), presence of different amounts of ethanol added to acetylene, and presence of NO on the concentrations of C2H2, C2H5OH, CO, CO2, NO, and HCN has been analyzed. The gas-phase kinetic mechanism used for calculations was that developed by Alzueta et al. (Alzueta, M. U.; Borruey, M.; Callejas, A.; Millera, A.; Bilbao, R. Combust. Flame 2008, 152, 377-386) for acetylene conversion, on the basis of a previous work by Skjoth-Rasmussen et al. (Skjøth-Rasmussen, M. S.; Glarborg, P.; Østberg, M.; Johannessen, J. T.; Livbjerg, H.; Jensen, A. D.; Christensen, T. S. Combust. Flame 2004, 136, 91-128), with reactions added from the ethanol oxidation mechanism of Alzueta and Hernández (Alzueta, M. U.; Hernández, J. M. Energy Fuels 2002, 16, 166-171), as well as reactions from the mechanism developed by Glarborg et al. (Glarborg, P.; Alzueta, M. U.; Dam-Johansen, K.; Miller, J. A. Combust. Flame 1998, 115, 1-27) to describe the interactions among C1/C2 hydrocarbons and nitric oxide. The experimental results show that the ethanol presence significantly modifies the acetylene conversion regime, inhibiting soot formation. An increase of the oxygen level and temperature favor acetylene conversion. The presence of NO results in some differences in relation to the oxidation regimes of the acetylene-ethanol blends. The reduction of NO by the mixture is favored at the highest temperatures of the considered range, above 1275 K, and for moderately fuel-ricb conditions ($łambda$ = 0.7). In general, the kinetic model satisfactorily simulates the experimental trends. Model predictions indicate that, under the conditions of this study, HCCO + NO is the most important reaction in reducing NO. Moreover, the ethanol presence slightly inhibits the NO reduction in relation to the oxidation of pure acetylene. textcopyright 2008 American Chemical Society.
Aguiar, Leonardo; Márquez-Montesinos, F; Gonzalo, Alberto; Sánchez, José Luis; Arauzo, Jesús
Influence of temperature and particle size on the fixed bed pyrolysis of orange peel residues Artículo de revista
En: Journal of Analytical and Applied Pyrolysis, vol. 83, no 1, pp. 124–130, 2008, ISSN: 01652370.
@article{Aguiar2008,
title = {Influence of temperature and particle size on the fixed bed pyrolysis of orange peel residues},
author = {Leonardo Aguiar and F Márquez-Montesinos and Alberto Gonzalo and José Luis Sánchez and Jesús Arauzo},
doi = {10.1016/j.jaap.2008.06.009},
issn = {01652370},
year = {2008},
date = {2008-09-01},
journal = {Journal of Analytical and Applied Pyrolysis},
volume = {83},
number = {1},
pages = {124--130},
publisher = {Elsevier},
abstract = {Orange peel is a residue from the production of juice. Its energetic valorisation could be interesting in areas where a different use, such as animal feed, is not possible. In order to investigate the viability of energy recovery, the pyrolysis of orange peel residues was studied in a fixed bed reactor, as an initial assessment of this process. The influence of pyrolysis temperature (300-600 °C) and particle size (dp < 300 $mu$m and dp > 800 $mu$m) on product distribution, gas composition and char heating value has been investigated using a factorial design of experiments. Gas, char and water are the main products obtained; tar is only about 6 wt.% of the initial residue. Temperature was found to be the parameter which exerts a more important influence on the results than particle size. textcopyright 2008 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Orange peel is a residue from the production of juice. Its energetic valorisation could be interesting in areas where a different use, such as animal feed, is not possible. In order to investigate the viability of energy recovery, the pyrolysis of orange peel residues was studied in a fixed bed reactor, as an initial assessment of this process. The influence of pyrolysis temperature (300-600 °C) and particle size (dp < 300 $mu$m and dp > 800 $mu$m) on product distribution, gas composition and char heating value has been investigated using a factorial design of experiments. Gas, char and water are the main products obtained; tar is only about 6 wt.% of the initial residue. Temperature was found to be the parameter which exerts a more important influence on the results than particle size. textcopyright 2008 Elsevier B.V. All rights reserved.