Articles Published in International Peer-Reviewed Journals (dec. 2020)
315
2021 |
Journal Articles |
Colom-Díaz, Juan Manuel; Millera, Ángela; Bilbao, Rafael; Alzueta, María U New results of H2S oxidation at high pressures. Experiments and kinetic modeling Journal Article Fuel, 285 , pp. 119261, 2021, ISSN: 00162361. @article{Colom-Diaz2021, title = {New results of H2S oxidation at high pressures. Experiments and kinetic modeling}, author = {Juan Manuel Colom-Díaz and Ángela Millera and Rafael Bilbao and María U Alzueta}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0016236120322572}, doi = {10.1016/j.fuel.2020.119261}, issn = {00162361}, year = {2021}, date = {2021-02-01}, journal = {Fuel}, volume = {285}, pages = {119261}, publisher = {Elsevier}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Colom-Díaz, Juan Manuel; Alzueta, María U; Zeng, Z; Altarawneh, M; Dlugogorski, B Z Oxidation of H2S and CH3SH in a jet-stirred reactor: Experiments and kinetic modeling Journal Article Fuel, 283 , 2021, ISSN: 00162361. @article{Colom-Diaz2021b, title = {Oxidation of H2S and CH3SH in a jet-stirred reactor: Experiments and kinetic modeling}, author = {Juan Manuel Colom-Díaz and María U Alzueta and Z Zeng and M Altarawneh and B Z Dlugogorski}, doi = {10.1016/j.fuel.2020.119258}, issn = {00162361}, year = {2021}, date = {2021-01-01}, journal = {Fuel}, volume = {283}, publisher = {Elsevier Ltd}, abstract = {This contribution reports experimental measurements of the oxidation of H2S and CH3SH, under atmospheric pressure in a jet-stirred reactor (JSR), in the temperature range of 600–1100 K and for stoichiometric and oxidizing conditions. We update a recent kinetic model, originally developed based on the measurements of oxidation of H2S and CH3SH in a tubular flow-reactor and apply it to simulate the experimental data. The CH3SH subset of the kinetic model features new reactions based on a recent theoretical work and the rate parameters proposed in the present investigation. The oxidation of CH3SH proceeds mainly through an intersystem crossing process that leads to the formation of sulfine (CH2SO). The unimolecular decomposition of CH2SO in two competing reactions produces CO + H2S and COS + H2. The results from the model concur well with the experimental measurements, both from the present work and from the literature. We demonstrate that, both H2S and CH3S exhibit a similar ignition temperature, due to the initiation step that involves the abstraction of H initially bonded to sulfur. It is expected that, the results from the present investigation find application in processing of sour gas, including shale gas, especially in the direct combustion of the gas (i.e., without purification) for energy production.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This contribution reports experimental measurements of the oxidation of H2S and CH3SH, under atmospheric pressure in a jet-stirred reactor (JSR), in the temperature range of 600–1100 K and for stoichiometric and oxidizing conditions. We update a recent kinetic model, originally developed based on the measurements of oxidation of H2S and CH3SH in a tubular flow-reactor and apply it to simulate the experimental data. The CH3SH subset of the kinetic model features new reactions based on a recent theoretical work and the rate parameters proposed in the present investigation. The oxidation of CH3SH proceeds mainly through an intersystem crossing process that leads to the formation of sulfine (CH2SO). The unimolecular decomposition of CH2SO in two competing reactions produces CO + H2S and COS + H2. The results from the model concur well with the experimental measurements, both from the present work and from the literature. We demonstrate that, both H2S and CH3S exhibit a similar ignition temperature, due to the initiation step that involves the abstraction of H initially bonded to sulfur. It is expected that, the results from the present investigation find application in processing of sour gas, including shale gas, especially in the direct combustion of the gas (i.e., without purification) for energy production. |
2020 |
Journal Articles |
Greco, Gianluca; Stasi, Christian Di; Rego, Filipe; González, Belén; Manyà, Joan Josep Effects of slow-pyrolysis conditions on the products yields and properties and on exergy efficiency: A comprehensive assessment for wheat straw Journal Article Applied Energy, 279 , pp. 115842, 2020, ISSN: 03062619. @article{Greco2020, title = {Effects of slow-pyrolysis conditions on the products yields and properties and on exergy efficiency: A comprehensive assessment for wheat straw}, author = {Gianluca Greco and Christian Di Stasi and Filipe Rego and Belén González and Joan Josep Manyà}, doi = {10.1016/j.apenergy.2020.115842}, issn = {03062619}, year = {2020}, date = {2020-12-01}, journal = {Applied Energy}, volume = {279}, pages = {115842}, publisher = {Elsevier Ltd}, abstract = {In the present work, the effects of the peak temperature (400–550 °C), absolute pressure (0.2–0.9 MPa), gas residence time (100–200 s) and reactor atmosphere (pure N2 or a mixture of CO2/N2) on the pyrolysis behavior of wheat straw pellets were investigated. A factorial design of experiments was adopted to assess the effects of the above-mentioned factors on the pyrolysis products, the exergy efficiencies related to them and to the overall process, and the heat required. The pyrolysis energy/exergy assessment is nowadays of great interest, for the scaling of the installations from lab-scale to commercial-scale. Results showed that, as expected, the peak temperature was the most influential factor on the yields and distributions of all the pyrolysis products as well as the char properties related to its potential stability and pore size distribution. However, an increased pressure enhanced the release of the gas species at the expense of the liquid products, without altering the final char yield. The char exergy efficiency was negatively affected by an increase in peak temperature, whereas its effect on the exergy efficiency of the produced gas resulted to be positive. It was also found that pressurized pyrolysis favored the exergy efficiency of the process, even at relatively high pyrolysis peak temperature. For the biomass feedstock and the range of operating conditions studied here, thermodynamic irreversibilities of the pyrolysis system were considerably lowered when the process was conducted at 550 °C, 0.9 MPa and using a mixture of CO2 and N2 as carrier gas at relatively short residence times.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the present work, the effects of the peak temperature (400–550 °C), absolute pressure (0.2–0.9 MPa), gas residence time (100–200 s) and reactor atmosphere (pure N2 or a mixture of CO2/N2) on the pyrolysis behavior of wheat straw pellets were investigated. A factorial design of experiments was adopted to assess the effects of the above-mentioned factors on the pyrolysis products, the exergy efficiencies related to them and to the overall process, and the heat required. The pyrolysis energy/exergy assessment is nowadays of great interest, for the scaling of the installations from lab-scale to commercial-scale. Results showed that, as expected, the peak temperature was the most influential factor on the yields and distributions of all the pyrolysis products as well as the char properties related to its potential stability and pore size distribution. However, an increased pressure enhanced the release of the gas species at the expense of the liquid products, without altering the final char yield. The char exergy efficiency was negatively affected by an increase in peak temperature, whereas its effect on the exergy efficiency of the produced gas resulted to be positive. It was also found that pressurized pyrolysis favored the exergy efficiency of the process, even at relatively high pyrolysis peak temperature. For the biomass feedstock and the range of operating conditions studied here, thermodynamic irreversibilities of the pyrolysis system were considerably lowered when the process was conducted at 550 °C, 0.9 MPa and using a mixture of CO2 and N2 as carrier gas at relatively short residence times. |
Adánez-Rubio, Iñaki; Ferreira, R; Rio, T; Alzueta, María U; Costa, Mário Soot and char formation in the gasification of pig manure in a drop tube reactor Journal Article Fuel, 281 , pp. 118738, 2020, ISSN: 00162361. @article{Adanez-Rubio2020b, title = {Soot and char formation in the gasification of pig manure in a drop tube reactor}, author = {Iñaki Adánez-Rubio and R Ferreira and T Rio and María U Alzueta and Mário Costa}, doi = {10.1016/j.fuel.2020.118738}, issn = {00162361}, year = {2020}, date = {2020-12-01}, journal = {Fuel}, volume = {281}, pages = {118738}, publisher = {Elsevier Ltd}, abstract = {Biomass gasification offers a significant potential to close the loop of agriculture and many other activities that produce biomass residues. Pig manure, a residue produced in farms, has a huge pollutant potential due to its high production and chemical characteristics. It is necessary to take some control measures to decrease it, being pig manure gasification an interesting option. The present work studies the impact of the gasification temperature and atmosphere on the syngas composition (CO, H2, CH4 and CO2) and formation of soot and char in the gasification of pig manure in a drop tube furnace. The temperature varied between 900 and 1200 °C, and the gasification atmospheres included mixtures of O2/N2, O2/CO2/N2 and O2/H2O/N2. The results revealed that i) the syngas H2/CO ratio and its low heating value increase as the gasification temperature increases regardless of the gasification atmosphere; ii) the addition of H2O to the O2/N2 gasification atmosphere augments significantly the syngas H2/CO ratio, but does not enhance its low heating value, while the addition of CO2 increases slightly the H2/CO ratio, but significantly the heating value, iii) for the present reactor, the optimum operating conditions for the gasification of the pig manure in terms of syngas heating value and yield are a gasification temperature of 1200 °C and a gasification atmosphere composed of a mixture of O2/CO2/N2; and iv) soot yields increase as the temperature increases when gasification occurs in the O2/N2 and O2/CO2/N2 environments, remaining almost constant in the O2/H2O/N2 environment.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Biomass gasification offers a significant potential to close the loop of agriculture and many other activities that produce biomass residues. Pig manure, a residue produced in farms, has a huge pollutant potential due to its high production and chemical characteristics. It is necessary to take some control measures to decrease it, being pig manure gasification an interesting option. The present work studies the impact of the gasification temperature and atmosphere on the syngas composition (CO, H2, CH4 and CO2) and formation of soot and char in the gasification of pig manure in a drop tube furnace. The temperature varied between 900 and 1200 °C, and the gasification atmospheres included mixtures of O2/N2, O2/CO2/N2 and O2/H2O/N2. The results revealed that i) the syngas H2/CO ratio and its low heating value increase as the gasification temperature increases regardless of the gasification atmosphere; ii) the addition of H2O to the O2/N2 gasification atmosphere augments significantly the syngas H2/CO ratio, but does not enhance its low heating value, while the addition of CO2 increases slightly the H2/CO ratio, but significantly the heating value, iii) for the present reactor, the optimum operating conditions for the gasification of the pig manure in terms of syngas heating value and yield are a gasification temperature of 1200 °C and a gasification atmosphere composed of a mixture of O2/CO2/N2; and iv) soot yields increase as the temperature increases when gasification occurs in the O2/N2 and O2/CO2/N2 environments, remaining almost constant in the O2/H2O/N2 environment. |
Di Stasi, Christian ; Greco, Gianluca; Canevesi, Rafael L S; Izquierdo, Teresa M; Fierro, Vanessa; Celzard, Alain; González, Belén; Manyà, Joan Josep Influence of activation conditions on textural properties and performance of activated biochars for pyrolysis vapors upgrading Journal Article Fuel, pp. 119759, 2020, ISSN: 00162361. @article{DiStasi2020, title = {Influence of activation conditions on textural properties and performance of activated biochars for pyrolysis vapors upgrading}, author = {Christian {Di Stasi} and Gianluca Greco and Rafael L S Canevesi and Teresa M Izquierdo and Vanessa Fierro and Alain Celzard and Belén González and Joan Josep Manyà}, doi = {10.1016/j.fuel.2020.119759}, issn = {00162361}, year = {2020}, date = {2020-12-01}, journal = {Fuel}, pages = {119759}, publisher = {Elsevier Ltd}, abstract = {The main aim of the present study is to provide a comprehensive assessment of the effects of process activation conditions on the textural properties of the resulting activated carbons, which were produced from wheat straw-derived biochar through chemical activation (with K2CO3 at different pressures and mass impregnation ratios) and physical activation (with CO2 at different temperatures and pressures). For chemically activated biochars, it was found that specific surface area and pore size distribution were both only positively affected by increasing the carbonate loading. However, physically activated biochars produced at the highest pressure and lowest temperature (1.0 MPa and 700 °C) had the highest surface areas and widest pore size distributions. The materials with the most appropriate textural properties were then tested as catalysts for steam and dry reforming of the aqueous phase of pyrolysis oil. The best catalytic performance (a total gas yield of 74% and a selectivity toward H2 of almost 40%) was observed for a physically activated biochar. This good performance was ascribed to the high availability of K0 on the catalyst surface, which could effectively promote the reactions involved in the upgrading process.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The main aim of the present study is to provide a comprehensive assessment of the effects of process activation conditions on the textural properties of the resulting activated carbons, which were produced from wheat straw-derived biochar through chemical activation (with K2CO3 at different pressures and mass impregnation ratios) and physical activation (with CO2 at different temperatures and pressures). For chemically activated biochars, it was found that specific surface area and pore size distribution were both only positively affected by increasing the carbonate loading. However, physically activated biochars produced at the highest pressure and lowest temperature (1.0 MPa and 700 °C) had the highest surface areas and widest pore size distributions. The materials with the most appropriate textural properties were then tested as catalysts for steam and dry reforming of the aqueous phase of pyrolysis oil. The best catalytic performance (a total gas yield of 74% and a selectivity toward H2 of almost 40%) was observed for a physically activated biochar. This good performance was ascribed to the high availability of K0 on the catalyst surface, which could effectively promote the reactions involved in the upgrading process. |
Atienza-Martínez, María; Binti Suraini, Nurull Nadia ; Ábrego, Javier; Fonts, Isabel; Lázaro, Luisa; Carstensen, Hans-Heinrich; Gea, Gloria Functionalization of sewage sludge char by partial oxidation with molecular oxygen to enhance its adsorptive properties Journal Article Journal of Cleaner Production, pp. 125201, 2020, ISSN: 09596526. @article{Atienza-Martinez2020b, title = {Functionalization of sewage sludge char by partial oxidation with molecular oxygen to enhance its adsorptive properties}, author = {María Atienza-Martínez and Nurull Nadia {Binti Suraini} and Javier Ábrego and Isabel Fonts and Luisa Lázaro and Hans-Heinrich Carstensen and Gloria Gea}, url = {https://linkinghub.elsevier.com/retrieve/pii/S0959652620352458}, doi = {10.1016/j.jclepro.2020.125201}, issn = {09596526}, year = {2020}, date = {2020-11-01}, journal = {Journal of Cleaner Production}, pages = {125201}, publisher = {Elsevier}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Gil-Lalaguna, Noemí; Afailal, Zainab; Aznar, María; Fonts, Isabel Journal of Cleaner Production, pp. 124417, 2020, ISSN: 09596526. @article{Noemi2020, title = {Exploring the sustainable production of ammonia by recycling N and H in biological residues: evolution of fuel-N during glutamic acid gasification}, author = {Noemí Gil-Lalaguna and Zainab Afailal and María Aznar and Isabel Fonts}, doi = {10.1016/j.jclepro.2020.124417}, issn = {09596526}, year = {2020}, date = {2020-10-01}, journal = {Journal of Cleaner Production}, pages = {124417}, publisher = {Elsevier BV}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Mergulhão, Carolina S; Carstensen, Hans-Heinrich; Song, Hwasup; Wagnon, Scott W; Pitz, William J; Vanhove, Guillaume Probing the antiknock effect of anisole through an ignition, speciation and modeling study of its blends with isooctane Journal Article Proceedings of the Combustion Institute, 2020, ISSN: 15407489. @article{Mergulhao2020, title = {Probing the antiknock effect of anisole through an ignition, speciation and modeling study of its blends with isooctane}, author = {Carolina S Mergulhão and Hans-Heinrich Carstensen and Hwasup Song and Scott W Wagnon and William J Pitz and Guillaume Vanhove}, doi = {10.1016/j.proci.2020.08.013}, issn = {15407489}, year = {2020}, date = {2020-10-01}, journal = {Proceedings of the Combustion Institute}, publisher = {Elsevier Ltd}, abstract = {In order to unravel the reaction pathways relevant to anisole co-oxidation within a fuel blend, a detailed study of isooctane/anisole blends was performed with the ULille RCM. Ignition delays as well as mole fraction profiles were measured during a two-stage ignition delay using sampling and GC techniques. These results are used to validate a kinetic model developed from ab initio calculations for the most relevant rate constants which included H-atom abstraction reactions from anisole, and reactions on the potential energy surfaces of methoxyphenyl + O2 and anisyl + O2. Pressure dependent rate constants were computed for the methoxyphenyl + O2 and anisyl + O2 reactive systems using master equation code analysis. The new kinetic model shows good agreement with the experimental data. Dual brute-force sensitivity analysis was performed, on both first- and second-stages of ignition, allowing the identification of the most important reactions in the prediction of both ignition delays. It was observed that while pure anisole does not show NTC behavior, a 60/40 isooctane/anisole blend displays such behavior, as well as two-stage ignition. This suggests anisole addition may not be as beneficial to knock resistance as expected from its high octane number. The kinetic modeling results demonstrate the importance of H-abstraction reactions both from the methoxy group and from the aryl ring in ortho-position and the addition of the resultant radicals to O2, mostly leading to the formation of polar or non-aromatic products.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In order to unravel the reaction pathways relevant to anisole co-oxidation within a fuel blend, a detailed study of isooctane/anisole blends was performed with the ULille RCM. Ignition delays as well as mole fraction profiles were measured during a two-stage ignition delay using sampling and GC techniques. These results are used to validate a kinetic model developed from ab initio calculations for the most relevant rate constants which included H-atom abstraction reactions from anisole, and reactions on the potential energy surfaces of methoxyphenyl + O2 and anisyl + O2. Pressure dependent rate constants were computed for the methoxyphenyl + O2 and anisyl + O2 reactive systems using master equation code analysis. The new kinetic model shows good agreement with the experimental data. Dual brute-force sensitivity analysis was performed, on both first- and second-stages of ignition, allowing the identification of the most important reactions in the prediction of both ignition delays. It was observed that while pure anisole does not show NTC behavior, a 60/40 isooctane/anisole blend displays such behavior, as well as two-stage ignition. This suggests anisole addition may not be as beneficial to knock resistance as expected from its high octane number. The kinetic modeling results demonstrate the importance of H-abstraction reactions both from the methoxy group and from the aryl ring in ortho-position and the addition of the resultant radicals to O2, mostly leading to the formation of polar or non-aromatic products. |
Adanez-Rubio, Iñaki; Millera, Ángela; Bilbao, Rafael; Alzueta, María U Effect of H2S on the S-PAH formation during ethylene pyrolysis Journal Article Fuel, 276 , pp. 118033, 2020, ISSN: 00162361. @article{Adanez-Rubio2020a, title = {Effect of H2S on the S-PAH formation during ethylene pyrolysis}, author = {Iñaki Adanez-Rubio and Ángela Millera and Rafael Bilbao and María U Alzueta}, doi = {10.1016/j.fuel.2020.118033}, issn = {00162361}, year = {2020}, date = {2020-09-01}, journal = {Fuel}, volume = {276}, pages = {118033}, publisher = {Elsevier Ltd}, abstract = {The effect of the H2S presence on the formation of six different sulphurated polycyclic hydrocarbons (S-PAH), during the pyrolysis of ethylene-H2S mixtures, has been studied in a tubular flow reactor installation. Experiments with different inlet H2S concentrations (0.3, 0.5 and 1%) and temperatures of reaction (between 1075 and 1475 K) have been carried out. The 16 compounds that the Environmental Protection Agency (EPA) has stated as EPA-PAH priority pollutants were also analysed. EPA-PAH compounds were the majority of quantified PAH, and also S-PAH were found and quantified. For temperatures studied, the S-PAH/EPA-PAH ratio values showed a maximum value at 1075 K and a minimum value at 1175 K. With respect to the effect of the inlet concentration of H2S, the S-PAH/EPA-PAH ratio values increased with the increase of the H2S concentration.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The effect of the H2S presence on the formation of six different sulphurated polycyclic hydrocarbons (S-PAH), during the pyrolysis of ethylene-H2S mixtures, has been studied in a tubular flow reactor installation. Experiments with different inlet H2S concentrations (0.3, 0.5 and 1%) and temperatures of reaction (between 1075 and 1475 K) have been carried out. The 16 compounds that the Environmental Protection Agency (EPA) has stated as EPA-PAH priority pollutants were also analysed. EPA-PAH compounds were the majority of quantified PAH, and also S-PAH were found and quantified. For temperatures studied, the S-PAH/EPA-PAH ratio values showed a maximum value at 1075 K and a minimum value at 1175 K. With respect to the effect of the inlet concentration of H2S, the S-PAH/EPA-PAH ratio values increased with the increase of the H2S concentration. |
Pizarro, Alejandro Herrero; Torija, Irene; Moreno, Reyes; Arauzo, Jesús; Monsalvo, Victor M Catalytic reduction of nitrate with Pd-In2O3 Journal Article Environmental Science and Pollution Research, 27 (26), pp. 33181–33191, 2020, ISSN: 0944-1344. @article{Pizarro2020, title = {Catalytic reduction of nitrate with Pd-In2O3}, author = {Alejandro Herrero Pizarro and Irene Torija and Reyes Moreno and Jesús Arauzo and Victor M Monsalvo}, url = {http://link.springer.com/10.1007/s11356-020-09459-9}, doi = {10.1007/s11356-020-09459-9}, issn = {0944-1344}, year = {2020}, date = {2020-09-01}, journal = {Environmental Science and Pollution Research}, volume = {27}, number = {26}, pages = {33181--33191}, publisher = {Springer}, abstract = {This work presents a novel catalyst preparation method and the optimization of operation conditions for an effective NO3− conversion with a high selectivity and stability that guarantee water quality for human consumption. Catalytic reduction of NO3− and NO2− was carried out with Pd supported on In2O3 under mild operation conditions (25 °C, 1 atm) with H2 and CO2 as reducing and acidifying agents, respectively. The catalyst was used in batch experiments showing the suppression of NO2− accumulation and low NH4+ selectivity at acid pH. Long-term experiments were carried out with Pd on $gamma$-Al2O3 spheres covered with In2O3. This catalyst presented a high stability during more than 700 h. A concentration of NO3− below 50 mg/L was achieved, producing less than 0.5 mg/L of NH4+ as reaction by-product by a strict limitation of the H2 fed and controlling several operating conditions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This work presents a novel catalyst preparation method and the optimization of operation conditions for an effective NO3− conversion with a high selectivity and stability that guarantee water quality for human consumption. Catalytic reduction of NO3− and NO2− was carried out with Pd supported on In2O3 under mild operation conditions (25 °C, 1 atm) with H2 and CO2 as reducing and acidifying agents, respectively. The catalyst was used in batch experiments showing the suppression of NO2− accumulation and low NH4+ selectivity at acid pH. Long-term experiments were carried out with Pd on $gamma$-Al2O3 spheres covered with In2O3. This catalyst presented a high stability during more than 700 h. A concentration of NO3− below 50 mg/L was achieved, producing less than 0.5 mg/L of NH4+ as reaction by-product by a strict limitation of the H2 fed and controlling several operating conditions. |
Tran, Luc Sy; Carstensen, Hans-Heinrich; Foo, Kae Ken; Lamoureux, Nathalie; Gosselin, Sylvie; Gasnot, Laurent; El-Bakali, Abderrahman; Desgroux, Pascale Experimental and modeling study of the high-temperature combustion chemistry of tetrahydrofurfuryl alcohol Journal Article Proceedings of the Combustion Institute, 2020, ISSN: 15407489. @article{Tran2020, title = {Experimental and modeling study of the high-temperature combustion chemistry of tetrahydrofurfuryl alcohol}, author = {Luc Sy Tran and Hans-Heinrich Carstensen and Kae Ken Foo and Nathalie Lamoureux and Sylvie Gosselin and Laurent Gasnot and Abderrahman El-Bakali and Pascale Desgroux}, doi = {10.1016/j.proci.2020.07.057}, issn = {15407489}, year = {2020}, date = {2020-09-01}, journal = {Proceedings of the Combustion Institute}, publisher = {Elsevier Ltd}, abstract = {Lignocellulosic tetrahydrofuranic (THF) biofuels have been identified as promising fuel candidates for spark-ignition (SI) engines. To support the potential use as transportation biofuels, fundamental studies of their combustion and emission behavior are highly important. In the present study, the high-temperature (HT) combustion chemistry of tetrahydrofurfuryl alcohol (THFA), a THF based biofuel, was investigated using a comprehensive experimental and numerical approach. Representative chemical species profiles in a stoichiometric premixed methane flame doped with $sim$20% (molar) THFA at 5.3 kPa were measured using online gas chromatography. The flame temperature was obtained by NO laser-induced fluorescence (LIF) thermometry. More than 40 chemical products were identified and quantified. Many of them such as ethylene, formaldehyde, acrolein, allyl alcohol, 2,3-dihydrofuran, 3,4-dihydropyran, 4-pentenal, and tetrahydrofuran-2-carbaldehyde are fuel-specific decomposition products formed in rather high concentrations. In the numerical part, as a complement to kinetic modeling, high-level theoretical calculations were performed to identify plausible reaction pathways that lead to the observed products. Furthermore, the rate coefficients of important reactions and the thermochemical properties of the related species were calculated. A detailed kinetic model for high-temperature combustion of THFA was developed, which reasonably predicts the experimental data. Subsequent rate analysis showed that THFA is mainly consumed by H-abstraction reactions yielding several fuel radicals that in turn undergo either $beta$-scission reactions or intramolecular radical addition that effectively leads to ring enlargement. The importance of specific reaction channels generally correlates with bond dissociation energies. Along THFA reaction routes, the derived species with cis configuration were found to be thermodynamically more stable than their corresponding trans configuration, which differs from usual observations for hydrocarbons.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Lignocellulosic tetrahydrofuranic (THF) biofuels have been identified as promising fuel candidates for spark-ignition (SI) engines. To support the potential use as transportation biofuels, fundamental studies of their combustion and emission behavior are highly important. In the present study, the high-temperature (HT) combustion chemistry of tetrahydrofurfuryl alcohol (THFA), a THF based biofuel, was investigated using a comprehensive experimental and numerical approach. Representative chemical species profiles in a stoichiometric premixed methane flame doped with $sim$20% (molar) THFA at 5.3 kPa were measured using online gas chromatography. The flame temperature was obtained by NO laser-induced fluorescence (LIF) thermometry. More than 40 chemical products were identified and quantified. Many of them such as ethylene, formaldehyde, acrolein, allyl alcohol, 2,3-dihydrofuran, 3,4-dihydropyran, 4-pentenal, and tetrahydrofuran-2-carbaldehyde are fuel-specific decomposition products formed in rather high concentrations. In the numerical part, as a complement to kinetic modeling, high-level theoretical calculations were performed to identify plausible reaction pathways that lead to the observed products. Furthermore, the rate coefficients of important reactions and the thermochemical properties of the related species were calculated. A detailed kinetic model for high-temperature combustion of THFA was developed, which reasonably predicts the experimental data. Subsequent rate analysis showed that THFA is mainly consumed by H-abstraction reactions yielding several fuel radicals that in turn undergo either $beta$-scission reactions or intramolecular radical addition that effectively leads to ring enlargement. The importance of specific reaction channels generally correlates with bond dissociation energies. Along THFA reaction routes, the derived species with cis configuration were found to be thermodynamically more stable than their corresponding trans configuration, which differs from usual observations for hydrocarbons. |
Arauzo, Pablo J; Olszewski, Maciej P; Wang, X; Pfersich, J; Sebastian, V; Manyà, Joan Josep; Hedin, Niklas; Kruse, Andrea Assessment of the effects of process water recirculation on the surface chemistry and morphology of hydrochar Journal Article Renewable Energy, 155 , pp. 1173–1180, 2020, ISSN: 18790682. @article{Arauzo2020a, title = {Assessment of the effects of process water recirculation on the surface chemistry and morphology of hydrochar}, author = {Pablo J Arauzo and Maciej P Olszewski and X Wang and J Pfersich and V Sebastian and Joan Josep Manyà and Niklas Hedin and Andrea Kruse}, doi = {10.1016/j.renene.2020.04.050}, issn = {18790682}, year = {2020}, date = {2020-08-01}, journal = {Renewable Energy}, volume = {155}, pages = {1173--1180}, publisher = {Elsevier Ltd}, abstract = {The effect of two process water (PW) recirculation strategies after hydrothermal carbonization (HTC) of brewers spent grains (BSG) is evaluated with the focus on the hydrochar characteristics. The HTC process has been carried out under different operating conditions, which are residence time between 2 and 4 h and temperature in the range of 200–220 °C. The composition of the hydrochars reveals that operating conditions have a more significant effect than PW recirculation. The composition of the liquid produced by HTC with PW recirculation is essentially controlled by the operating temperature, for instance, the total organic carbon (TOC) in the PW changes in the narrow range of 200–220 °C. A detailed analysis of PW also has been done. The main components of the liquid phase are lactic, formic, acetic, levulinic, and propionic acid as well as 5-hydroxymethylfurfural, that affect the surface structure of the hydrochars.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The effect of two process water (PW) recirculation strategies after hydrothermal carbonization (HTC) of brewers spent grains (BSG) is evaluated with the focus on the hydrochar characteristics. The HTC process has been carried out under different operating conditions, which are residence time between 2 and 4 h and temperature in the range of 200–220 °C. The composition of the hydrochars reveals that operating conditions have a more significant effect than PW recirculation. The composition of the liquid produced by HTC with PW recirculation is essentially controlled by the operating temperature, for instance, the total organic carbon (TOC) in the PW changes in the narrow range of 200–220 °C. A detailed analysis of PW also has been done. The main components of the liquid phase are lactic, formic, acetic, levulinic, and propionic acid as well as 5-hydroxymethylfurfural, that affect the surface structure of the hydrochars. |
Arauzo, Pablo J; Atienza-Martínez, María; Ábrego, Javier; Olszewski, Maciej P; Cao, Zebin; Kruse, Andrea Combustion Characteristics of Hydrochar and Pyrochar Derived from Digested Sewage Sludge Journal Article Energies, 13 (16), pp. 4164, 2020, ISSN: 1996-1073. @article{Arauzo2020b, title = {Combustion Characteristics of Hydrochar and Pyrochar Derived from Digested Sewage Sludge}, author = {Pablo J Arauzo and María Atienza-Martínez and Javier Ábrego and Maciej P Olszewski and Zebin Cao and Andrea Kruse}, url = {https://www.mdpi.com/1996-1073/13/16/4164}, doi = {10.3390/en13164164}, issn = {1996-1073}, year = {2020}, date = {2020-08-01}, journal = {Energies}, volume = {13}, number = {16}, pages = {4164}, publisher = {MDPI AG}, abstract = { In this paper, hydrochars and pyrochars were produced at 260 °C under different residence times (2 and 4 h) using anaerobic digested sewage sludge (SSL) as initial feedstock. The effect of reaction time on the fuel properties of hydrochars and pyrochars was evaluated. Moreover, the combustion kinetics of raw SSL and the derived pyrochars and hydrochars without coal blending were determined at two different air flows (20 and 90 mL/min) and compared. In the same conditions, the yield of hydrochar was significantly lower than that of pyrochar, confirming the different reaction pathways followed in each process. The results showed hydrochars have lower carbon recovery and energy yield than pyrochars, making the latter more suitable for energy purposes. The thermogravimetric combustion study showed that both thermochemical treatments increased the ignition temperature but decreased the burnout temperature, which results in higher stability during handling and storage. However, raw SSL is better for combustion than hydrochar according to the combustibility index. In addition, the kinetic study showed that the activation energy of the combustion of biochars, especially pyrochar, is lower than that of raw SSL, which is advantageous for their combustion. },keywords = {}, pubstate = {published}, tppubtype = {article} } <p>In this paper, hydrochars and pyrochars were produced at 260 °C under different residence times (2 and 4 h) using anaerobic digested sewage sludge (SSL) as initial feedstock. The effect of reaction time on the fuel properties of hydrochars and pyrochars was evaluated. Moreover, the combustion kinetics of raw SSL and the derived pyrochars and hydrochars without coal blending were determined at two different air flows (20 and 90 mL/min) and compared. In the same conditions, the yield of hydrochar was significantly lower than that of pyrochar, confirming the different reaction pathways followed in each process. The results showed hydrochars have lower carbon recovery and energy yield than pyrochars, making the latter more suitable for energy purposes. The thermogravimetric combustion study showed that both thermochemical treatments increased the ignition temperature but decreased the burnout temperature, which results in higher stability during handling and storage. However, raw SSL is better for combustion than hydrochar according to the combustibility index. In addition, the kinetic study showed that the activation energy of the combustion of biochars, especially pyrochar, is lower than that of raw SSL, which is advantageous for their combustion.</p> |
González, Belén; Manyà, Joan Josep Activated olive mill waste-based hydrochars as selective adsorbents for CO2 capture under postcombustion conditions Journal Article Chemical Engineering and Processing - Process Intensification, 149 , pp. 107830, 2020, ISSN: 02552701. @article{Gonzalez2020, title = {Activated olive mill waste-based hydrochars as selective adsorbents for CO2 capture under postcombustion conditions}, author = {Belén González and Joan Josep Manyà}, doi = {10.1016/j.cep.2020.107830}, issn = {02552701}, year = {2020}, date = {2020-03-01}, journal = {Chemical Engineering and Processing - Process Intensification}, volume = {149}, pages = {107830}, publisher = {Elsevier B.V.}, abstract = {Porous carbons are considered to be promising sorbents for carbon capture and sequestration. As precursors, the use of biomass materials has acquiring special interest due to its low cost and high availability. Among all the possibilities to convert low-value biomass into these interesting sorbents, hydrothermal carbonization has demonstrated several advantages such as lower energy consumption over pyrolysis. In this work, activated hydrochars using two-phase olive mill waste as precursor have been prepared through physical and chemical activation using CO2 and KOH, respectively. Additionally, with the aim to study the influence of the nitrogen on their adsorption capacity, N-doped adsorbents have been prepared through a one-step hydrothermal carbonization. The behaviour of these adsorbents has been studied in terms of CO2 uptake capacity at an absolute pressure of 15 kPa and temperatures of 0, 25 and 75 °C, apparent selectivity towards CO2 over N2, and isosteric heat of adsorption. Among all these samples, the physically activated hydrochar appears to be the best due to its higher CO2 uptakes, adsorption rates and values of selectivity at 25 °C. Therefore, considering these results, doping these materials with nitrogen does not appear to enhance their adsorption properties, contrary to what some authors have previously reported.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Porous carbons are considered to be promising sorbents for carbon capture and sequestration. As precursors, the use of biomass materials has acquiring special interest due to its low cost and high availability. Among all the possibilities to convert low-value biomass into these interesting sorbents, hydrothermal carbonization has demonstrated several advantages such as lower energy consumption over pyrolysis. In this work, activated hydrochars using two-phase olive mill waste as precursor have been prepared through physical and chemical activation using CO2 and KOH, respectively. Additionally, with the aim to study the influence of the nitrogen on their adsorption capacity, N-doped adsorbents have been prepared through a one-step hydrothermal carbonization. The behaviour of these adsorbents has been studied in terms of CO2 uptake capacity at an absolute pressure of 15 kPa and temperatures of 0, 25 and 75 °C, apparent selectivity towards CO2 over N2, and isosteric heat of adsorption. Among all these samples, the physically activated hydrochar appears to be the best due to its higher CO2 uptakes, adsorption rates and values of selectivity at 25 °C. Therefore, considering these results, doping these materials with nitrogen does not appear to enhance their adsorption properties, contrary to what some authors have previously reported. |
Colom-Díaz, Juan Manuel; Leciñena, M; Peláez, A; Abián, María; Millera, Ángela; Bilbao, Rafael; Alzueta, María U Study of the conversion of CH4/H2S mixtures at different pressures Journal Article Fuel, 262 , pp. 116484, 2020, ISSN: 00162361. @article{Colom-Diaz2020, title = {Study of the conversion of CH4/H2S mixtures at different pressures}, author = {Juan Manuel Colom-Díaz and M Leciñena and A Peláez and María Abián and Ángela Millera and Rafael Bilbao and María U Alzueta}, doi = {10.1016/j.fuel.2019.116484}, issn = {00162361}, year = {2020}, date = {2020-02-01}, journal = {Fuel}, volume = {262}, pages = {116484}, publisher = {Elsevier Ltd}, abstract = {Due to the different scenarios where sour gas is present, its composition can be different and, therefore, it can be exploited through different processes, being combustion one of them. In this context, this work deals with the oxidation of CH4 and H2S at different pressures and under a wide variety of conditions. The oxidation has been evaluated experimentally in two different flow reactor set-ups, one working at atmospheric pressure and another one operating from atmospheric to high pressures (40 bar). Different CH4/H2S mixtures have been tested, together with different oxygen concentrations and in the temperature range of 500–1400 K. The experimental results obtained show that the oxidation of the CH4/H2S mixtures is shifted to lower temperatures as pressure increases, obtaining the same trends at atmospheric pressure in both experimental set-ups. H2S oxidation occurs prior to CH4 oxidation at all conditions, providing radicals to the system that promote CH4 oxidation to lower temperatures (compared to neat CH4 oxidation). This effect is more relevant as pressure increases. H2S oxidation is inhibited by CH4 at atmospheric pressure, being more noticeable when the CH4/H2S ratio is higher. At higher pressures, the H2S conversion occurs similarly in the absence or presence of CH4. The experimental results have been modeled with an updated kinetic model from previous works from the literature, which, in general, matches well the experimental trends, while some discrepancies between experimental and modeling results at atmospheric pressure and 40 bar are found in the conversion of H2S and CH4.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Due to the different scenarios where sour gas is present, its composition can be different and, therefore, it can be exploited through different processes, being combustion one of them. In this context, this work deals with the oxidation of CH4 and H2S at different pressures and under a wide variety of conditions. The oxidation has been evaluated experimentally in two different flow reactor set-ups, one working at atmospheric pressure and another one operating from atmospheric to high pressures (40 bar). Different CH4/H2S mixtures have been tested, together with different oxygen concentrations and in the temperature range of 500–1400 K. The experimental results obtained show that the oxidation of the CH4/H2S mixtures is shifted to lower temperatures as pressure increases, obtaining the same trends at atmospheric pressure in both experimental set-ups. H2S oxidation occurs prior to CH4 oxidation at all conditions, providing radicals to the system that promote CH4 oxidation to lower temperatures (compared to neat CH4 oxidation). This effect is more relevant as pressure increases. H2S oxidation is inhibited by CH4 at atmospheric pressure, being more noticeable when the CH4/H2S ratio is higher. At higher pressures, the H2S conversion occurs similarly in the absence or presence of CH4. The experimental results have been modeled with an updated kinetic model from previous works from the literature, which, in general, matches well the experimental trends, while some discrepancies between experimental and modeling results at atmospheric pressure and 40 bar are found in the conversion of H2S and CH4. |
Atienza-Martínez, María; Ábrego, Javier; Gea, Gloria; Marías, Frédéric Pyrolysis of dairy cattle manure: evolution of char characteristics Journal Article Journal of Analytical and Applied Pyrolysis, 145 , pp. 104724, 2020, ISSN: 01652370. @article{Atienza-Martinez2020, title = {Pyrolysis of dairy cattle manure: evolution of char characteristics}, author = {María Atienza-Martínez and Javier Ábrego and Gloria Gea and Frédéric Marías}, doi = {10.1016/j.jaap.2019.104724}, issn = {01652370}, year = {2020}, date = {2020-01-01}, journal = {Journal of Analytical and Applied Pyrolysis}, volume = {145}, pages = {104724}, publisher = {Elsevier B.V.}, abstract = {Livestock manure management constitutes a major challenge at this time. Traditionally, this waste has been used as fertilizer. Excessive application of this residual organic matter on agricultural soils can cause soil quality degradation due to heavy metals accumulation, migration of pathogens to water sources and food, and generation of greenhouse gases. As a promising alternative to land application, pyrolysis of livestock manure allows to obtain biochar, bio-oil and syngas. The goal of this work is to study slow pyrolysis of digested dairy cattle manure (DM) both through one-step and multi-step pyrolysis at increasing temperature in the range 250-600 °C. The non-condensable gases composition was continuously analyzed by gas chromatography. Char properties were characterized by ultimate analysis, heavy metals content, ash content, higher heating value (HHV), pH, electrical conductivity (EC), water holding capacity (WHC), cation exchange capacity (CEC), textural properties (specific surface area, pore volume and average pore width) and Fourier Transform Infrared (FTIR) spectroscopy. The experimental results showed that both the product distribution and the properties of char depended on pyrolysis temperature. Char obtained after the last step of multi-step pyrolysis had similar properties to that obtained in one-step pyrolysis. Thus, the cooling and re-heating of the solid between steps did not have a significant effect on the pyrolysis pathway. Pyrolysis at between 400-550 °C allowed to reach a compromise between char pH and electrical conductivity for its potential use as soil amendment.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Livestock manure management constitutes a major challenge at this time. Traditionally, this waste has been used as fertilizer. Excessive application of this residual organic matter on agricultural soils can cause soil quality degradation due to heavy metals accumulation, migration of pathogens to water sources and food, and generation of greenhouse gases. As a promising alternative to land application, pyrolysis of livestock manure allows to obtain biochar, bio-oil and syngas. The goal of this work is to study slow pyrolysis of digested dairy cattle manure (DM) both through one-step and multi-step pyrolysis at increasing temperature in the range 250-600 °C. The non-condensable gases composition was continuously analyzed by gas chromatography. Char properties were characterized by ultimate analysis, heavy metals content, ash content, higher heating value (HHV), pH, electrical conductivity (EC), water holding capacity (WHC), cation exchange capacity (CEC), textural properties (specific surface area, pore volume and average pore width) and Fourier Transform Infrared (FTIR) spectroscopy. The experimental results showed that both the product distribution and the properties of char depended on pyrolysis temperature. Char obtained after the last step of multi-step pyrolysis had similar properties to that obtained in one-step pyrolysis. Thus, the cooling and re-heating of the solid between steps did not have a significant effect on the pyrolysis pathway. Pyrolysis at between 400-550 °C allowed to reach a compromise between char pH and electrical conductivity for its potential use as soil amendment. |
Videgain-Marco, María; Marco-Montori, Pedro; Martí-Dalmau, Clara; del Jaizme-Vega, María Carmen; Manyà, Joan Josep; García-Ramos, Javier F Effects of Biochar Application in a Sorghum Crop under Greenhouse Conditions: Growth Parameters and Physicochemical Fertility Journal Article Agronomy, 10 (1), pp. 104, 2020, ISSN: 2073-4395. @article{Videgain-Marco2020, title = {Effects of Biochar Application in a Sorghum Crop under Greenhouse Conditions: Growth Parameters and Physicochemical Fertility}, author = {María Videgain-Marco and Pedro Marco-Montori and Clara Martí-Dalmau and María Carmen del Jaizme-Vega and Joan Josep Manyà and Javier F García-Ramos}, url = {https://www.mdpi.com/2073-4395/10/1/104}, doi = {10.3390/agronomy10010104}, issn = {2073-4395}, year = {2020}, date = {2020-01-01}, journal = {Agronomy}, volume = {10}, number = {1}, pages = {104}, publisher = {MDPI AG}, abstract = {Application of biochar from vine shoots (Vitis vinifera L.) as an organic amendment in the soil is an alternative agricultural management of interest. The behavior of this type of amendment in the soil requires more information to adjust the pyrolysis conditions in order to obtain a high-quality biochar. The aim of this work is determining the influence of the application of this type of biochar on the soil-plant system. For this purpose, an agronomic test was performed in greenhouse pots. A randomized tri-factorial block design was adopted with the following factors: final pyrolysis temperature (400 and 600 °C), application rate (0 wt. % as a control, 1.5 and 3 wt. %) and texture of the growing media (sandy-loam and clay-loam origin). The selected crop was sorghum (Sorghum bicolor L. Moench), the development and production of which was evaluated during two complete growing cycles under greenhouse conditions. Application of biochar produced at 400 °C significantly increased plants roots dry weight in the sandy-loam growing substrate (52% compared to the control). Grain production was also significantly affected by biochar application, showing better results after addition of biochar produced at 400 °C. Water holding capacity and K, Ca, and Mg contents were enhanced by biochar addition, with evident effects of the application ratios for some of these variables. The effect on the pH of substrates in the sandy-loam texture was weak; however, a significant decrease was observed after the addition of biochar produced at 600 °C.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Application of biochar from vine shoots (Vitis vinifera L.) as an organic amendment in the soil is an alternative agricultural management of interest. The behavior of this type of amendment in the soil requires more information to adjust the pyrolysis conditions in order to obtain a high-quality biochar. The aim of this work is determining the influence of the application of this type of biochar on the soil-plant system. For this purpose, an agronomic test was performed in greenhouse pots. A randomized tri-factorial block design was adopted with the following factors: final pyrolysis temperature (400 and 600 °C), application rate (0 wt. % as a control, 1.5 and 3 wt. %) and texture of the growing media (sandy-loam and clay-loam origin). The selected crop was sorghum (Sorghum bicolor L. Moench), the development and production of which was evaluated during two complete growing cycles under greenhouse conditions. Application of biochar produced at 400 °C significantly increased plants roots dry weight in the sandy-loam growing substrate (52% compared to the control). Grain production was also significantly affected by biochar application, showing better results after addition of biochar produced at 400 °C. Water holding capacity and K, Ca, and Mg contents were enhanced by biochar addition, with evident effects of the application ratios for some of these variables. The effect on the pH of substrates in the sandy-loam texture was weak; however, a significant decrease was observed after the addition of biochar produced at 600 °C. |
Manyà, Joan Josep; García-Morcate, David; González, Belén Adsorption Performance of Physically Activated Biochars for Postcombustion CO2 Capture from Dry and Humid Flue Gas Journal Article Applied Sciences, 10 (1), pp. 376, 2020, ISSN: 2076-3417. @article{Manya2020, title = {Adsorption Performance of Physically Activated Biochars for Postcombustion CO2 Capture from Dry and Humid Flue Gas}, author = {Joan Josep Manyà and David García-Morcate and Belén González}, url = {https://www.mdpi.com/2076-3417/10/1/376}, doi = {10.3390/app10010376}, issn = {2076-3417}, year = {2020}, date = {2020-01-01}, journal = {Applied Sciences}, volume = {10}, number = {1}, pages = {376}, publisher = {MDPI AG}, abstract = {In the present study, the performance of four biomass-derived physically activated biochars for dynamic CO2 capture was assessed. Biochars were first produced from vine shoots and wheat straw pellets through slow pyrolysis (at pressures of 0.1 and 0.5 MPa) and then activated with CO2 (at 0.1 MPa and 800 °C) up to different degrees of burn-off. Cyclic adsorption-desorption measurements were conducted under both dry and humid conditions using a packed-bed of adsorbent at relatively short residence times of the gas phase (12–13 s). The adsorbent prepared from the vine shoots-derived biochar obtained by atmospheric pyrolysis, which showed the most hierarchical pore size distribution, exhibited a good and stable performance under dry conditions and at an adsorption temperature of 50 °C, due to the enhanced CO2 adsorption and desorption rates. However, the presence of relatively high concentrations of water vapor in the feeding gas clearly interfered with the CO2 adsorption mechanism, leading to significantly shorter breakthrough times. In this case, the highest percentages of a used bed were achieved by one of the other activated biochars tested, which was prepared from the wheat straw-derived biochar obtained by pressurized pyrolysis.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the present study, the performance of four biomass-derived physically activated biochars for dynamic CO2 capture was assessed. Biochars were first produced from vine shoots and wheat straw pellets through slow pyrolysis (at pressures of 0.1 and 0.5 MPa) and then activated with CO2 (at 0.1 MPa and 800 °C) up to different degrees of burn-off. Cyclic adsorption-desorption measurements were conducted under both dry and humid conditions using a packed-bed of adsorbent at relatively short residence times of the gas phase (12–13 s). The adsorbent prepared from the vine shoots-derived biochar obtained by atmospheric pyrolysis, which showed the most hierarchical pore size distribution, exhibited a good and stable performance under dry conditions and at an adsorption temperature of 50 °C, due to the enhanced CO2 adsorption and desorption rates. However, the presence of relatively high concentrations of water vapor in the feeding gas clearly interfered with the CO2 adsorption mechanism, leading to significantly shorter breakthrough times. In this case, the highest percentages of a used bed were achieved by one of the other activated biochars tested, which was prepared from the wheat straw-derived biochar obtained by pressurized pyrolysis. |
2019 |
Journal Articles |
Colom-Díaz, Juan Manuel; Abián, María; Millera, Ángela; Bilbao, Rafael; Alzueta, María U Influence of pressure on H2S oxidation. Experiments and kinetic modeling Journal Article Fuel, 258 , pp. 116145, 2019, ISSN: 00162361. @article{Colom-Diaz2019b, title = {Influence of pressure on H2S oxidation. Experiments and kinetic modeling}, author = {Juan Manuel Colom-Díaz and María Abián and Ángela Millera and Rafael Bilbao and María U Alzueta}, doi = {10.1016/j.fuel.2019.116145}, issn = {00162361}, year = {2019}, date = {2019-12-01}, journal = {Fuel}, volume = {258}, pages = {116145}, publisher = {Elsevier Ltd}, abstract = {The oxidation of H2S at different manometric pressures (0.6–40 bar), in the temperature range of 500–1000 K and under slightly oxidizing conditions ($łambda$ = 2), has been studied. Experiments have been performed in a quartz tubular flow reactor. The results have shown that H2S conversion shifts to lower temperatures as the pressure increases. The kinetic model used in this work is based on a previous one proposed by the authors to describe H2S oxidation at atmospheric pressure, which has been updated with a H2/O2 reaction subset for high pressures. Model results match fairly well the experimental ones both from the present work and from the literature. The reaction pathways of H2S oxidation analyzed are similar to the ones at atmospheric pressure. The differences are found in the radicals that are involved in the oxidation process at the different pressures. For a given temperature it is shown that, under the operating conditions of this work, pressure will have a major role than the gas residence time in the oxidation rate.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The oxidation of H2S at different manometric pressures (0.6–40 bar), in the temperature range of 500–1000 K and under slightly oxidizing conditions ($łambda$ = 2), has been studied. Experiments have been performed in a quartz tubular flow reactor. The results have shown that H2S conversion shifts to lower temperatures as the pressure increases. The kinetic model used in this work is based on a previous one proposed by the authors to describe H2S oxidation at atmospheric pressure, which has been updated with a H2/O2 reaction subset for high pressures. Model results match fairly well the experimental ones both from the present work and from the literature. The reaction pathways of H2S oxidation analyzed are similar to the ones at atmospheric pressure. The differences are found in the radicals that are involved in the oxidation process at the different pressures. For a given temperature it is shown that, under the operating conditions of this work, pressure will have a major role than the gas residence time in the oxidation rate. |
Plaza, Daniel; Artigas, Julia; Ábrego, Javier; Gonzalo, Alberto; Sánchez, José Luis; Dro, Augustin Diomandé; Richardson, Yohan Design and operation of a small-scale carbonization kiln for cashew nutshell valorization in Burkina Faso Journal Article Energy for Sustainable Development, 53 , pp. 71–80, 2019, ISSN: 23524669. @article{Plaza2019, title = {Design and operation of a small-scale carbonization kiln for cashew nutshell valorization in Burkina Faso}, author = {Daniel Plaza and Julia Artigas and Javier Ábrego and Alberto Gonzalo and José Luis Sánchez and Augustin Diomandé Dro and Yohan Richardson}, doi = {10.1016/j.esd.2019.10.005}, issn = {23524669}, year = {2019}, date = {2019-12-01}, journal = {Energy for Sustainable Development}, volume = {53}, pages = {71--80}, publisher = {Elsevier B.V.}, abstract = {This paper describes the process of planning, design, building and first operation tests of a carbonization reactor for the valorization of cashew nutshells, obtained as byproduct from small-scale cashew cultivation and processing in Bobo-Dioulasso, Burkina Faso. The main technical requirements for the reactor were: low cost and ease of construction, robustness, autothermal operation, no need for pre or post-treatments for feedstock and products, and readily useable product fractions in a local scale. Design modifications are discussed and justified. Characterization of the raw material, data from the first successful operational tests, as well as product distribution and characterization, are presented. This carbonization prototype allows for the sustainable valorization of an otherwise problematic biomass residue, creating added-value products that would enhance the economic profitability of local processors. The use of the main charcoal product as a fuel substitute for household cooking is preliminarily assessed, and the recovery of potentially valuable cashew nutshell liquid (CNSL) is accomplished.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This paper describes the process of planning, design, building and first operation tests of a carbonization reactor for the valorization of cashew nutshells, obtained as byproduct from small-scale cashew cultivation and processing in Bobo-Dioulasso, Burkina Faso. The main technical requirements for the reactor were: low cost and ease of construction, robustness, autothermal operation, no need for pre or post-treatments for feedstock and products, and readily useable product fractions in a local scale. Design modifications are discussed and justified. Characterization of the raw material, data from the first successful operational tests, as well as product distribution and characterization, are presented. This carbonization prototype allows for the sustainable valorization of an otherwise problematic biomass residue, creating added-value products that would enhance the economic profitability of local processors. The use of the main charcoal product as a fuel substitute for household cooking is preliminarily assessed, and the recovery of potentially valuable cashew nutshell liquid (CNSL) is accomplished. |
