2021
Journal Articles
Colom-Díaz, Juan Manuel; Millera, Ángela; Bilbao, Rafael; Alzueta, María U
Conversion of H2S/O2/NO mixtures at different pressures. Experiments and kinetic modeling Journal Article
In: Fuel, vol. 290, pp. 120060, 2021, ISSN: 00162361.
@article{Colom-Diaz2021b,
title = {Conversion of H2S/O2/NO mixtures at different pressures. Experiments and kinetic modeling},
author = {Juan Manuel Colom-Díaz and Ángela Millera and Rafael Bilbao and María U Alzueta},
doi = {10.1016/j.fuel.2020.120060},
issn = {00162361},
year = {2021},
date = {2021-04-01},
journal = {Fuel},
volume = {290},
pages = {120060},
publisher = {Elsevier Ltd},
abstract = {The present study deals with the oxidation of H2S/NO mixtures, in the temperature range of 475–1400 K, at atmospheric pressure and 20 bar of manometric pressure. The experiments have been performed in two different set-ups, using tubular flow reactors, for different air excess ratios ($łambda$H2S = 0.3–6). A kinetic model has been updated with recent reactions from the literature. When NO is present, the oxidation of H2S at atmospheric pressure proceeds at slightly higher temperatures (25 K) with respect to neat H2S oxidation. At high pressure (20 bar), the experiments of the oxidation of H2S in the absence and presence of NO have been performed only at oxidizing conditions ($łambda$H2S = 2 and $łambda$H2S = 6), in order to avoid sulfur formation under reducing conditions. The outcomes of these experiments show that, in presence of NO, at the lowest temperature considered (475 K), at least 50% of H2S conversion for $łambda$H2S = 2 and 90% for $łambda$H2S = 6 is obtained. In order to further evaluate the influence of the presence of NO in H2S oxidation, additional experiments of neat NO oxidation have been performed. As NO2 formation is favored at high pressures and high O2 concentrations, the NO2-H2S interaction is thought to be responsible for the consumption of H2S, even at low temperatures (475 K). While the kinetic mechanism is able to reproduce the experimental results at atmospheric pressure, discrepancies are more relevant at high pressure (20 bar).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The present study deals with the oxidation of H2S/NO mixtures, in the temperature range of 475–1400 K, at atmospheric pressure and 20 bar of manometric pressure. The experiments have been performed in two different set-ups, using tubular flow reactors, for different air excess ratios ($łambda$H2S = 0.3–6). A kinetic model has been updated with recent reactions from the literature. When NO is present, the oxidation of H2S at atmospheric pressure proceeds at slightly higher temperatures (25 K) with respect to neat H2S oxidation. At high pressure (20 bar), the experiments of the oxidation of H2S in the absence and presence of NO have been performed only at oxidizing conditions ($łambda$H2S = 2 and $łambda$H2S = 6), in order to avoid sulfur formation under reducing conditions. The outcomes of these experiments show that, in presence of NO, at the lowest temperature considered (475 K), at least 50% of H2S conversion for $łambda$H2S = 2 and 90% for $łambda$H2S = 6 is obtained. In order to further evaluate the influence of the presence of NO in H2S oxidation, additional experiments of neat NO oxidation have been performed. As NO2 formation is favored at high pressures and high O2 concentrations, the NO2-H2S interaction is thought to be responsible for the consumption of H2S, even at low temperatures (475 K). While the kinetic mechanism is able to reproduce the experimental results at atmospheric pressure, discrepancies are more relevant at high pressure (20 bar).
Raso, Raquel; García, Lucía; Ruiz, Joaquín; Oliva, Miriam; Arauzo, Jesús
Aqueous phase hydrogenolysis of glycerol over Ni/Al-Fe catalysts without external hydrogen addition Journal Article
In: Applied Catalysis B: Environmental, vol. 283, pp. 119598, 2021, ISSN: 09263373.
@article{Raso2021,
title = {Aqueous phase hydrogenolysis of glycerol over Ni/Al-Fe catalysts without external hydrogen addition},
author = {Raquel Raso and Lucía García and Joaquín Ruiz and Miriam Oliva and Jesús Arauzo},
doi = {10.1016/j.apcatb.2020.119598},
issn = {09263373},
year = {2021},
date = {2021-04-01},
journal = {Applied Catalysis B: Environmental},
volume = {283},
pages = {119598},
publisher = {Elsevier B.V.},
abstract = {The present work studied the aqueous phase hydrogenolysis (APH) of glycerol (a by-product of biodiesel manufacturing) without external hydrogen addition to produce value-added products. A series of catalysts based on 28 molar % of Ni were prepared through co-precipitation by changing the Al/Fe molar ratio. The calcined and used catalysts were characterized by several techniques (ICP-OES, N2-physisorption, XRD, H2-TPR, NH3-TPD, FESEM and STEM). This work examines the effects of the molar ratio of Al/Fe on the physicochemical characteristics of Ni/Al-Fe catalysts and during the APH of glycerol. All the catalysts showed low carbon yields to gases and high carbon yields to liquid products, mainly 1,2-propanediol, acetol and ethylene glycol. Ni/Al3Fe1 catalyst gave the best performance in the APH of glycerol: the highest glycerol conversion (42.31 %), carbon yield to gases (6.57 %) and carbon yield to liquids (30.45%). 1,2-propanediol was the liquid product with the highest carbon selectivity (70.89%).},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The present work studied the aqueous phase hydrogenolysis (APH) of glycerol (a by-product of biodiesel manufacturing) without external hydrogen addition to produce value-added products. A series of catalysts based on 28 molar % of Ni were prepared through co-precipitation by changing the Al/Fe molar ratio. The calcined and used catalysts were characterized by several techniques (ICP-OES, N2-physisorption, XRD, H2-TPR, NH3-TPD, FESEM and STEM). This work examines the effects of the molar ratio of Al/Fe on the physicochemical characteristics of Ni/Al-Fe catalysts and during the APH of glycerol. All the catalysts showed low carbon yields to gases and high carbon yields to liquid products, mainly 1,2-propanediol, acetol and ethylene glycol. Ni/Al3Fe1 catalyst gave the best performance in the APH of glycerol: the highest glycerol conversion (42.31 %), carbon yield to gases (6.57 %) and carbon yield to liquids (30.45%). 1,2-propanediol was the liquid product with the highest carbon selectivity (70.89%).
Raso, Raquel; Tovar, M.; Lasobras, Javier; Herguido, Javier; Kumakiri, I.; Araki, S.; Menéndez, Miguel
Zeolite membranes: Comparison in the separation of H2O/H2/CO2 mixtures and test of a reactor for CO2 hydrogenation to methanol Journal Article
In: Catalysis Today, vol. 364, pp. 270–275, 2021, ISSN: 0920-5861.
@article{raso_zeolite_2021,
title = {Zeolite membranes: Comparison in the separation of H2O/H2/CO2 mixtures and test of a reactor for CO2 hydrogenation to methanol},
author = {Raquel Raso and M. Tovar and Javier Lasobras and Javier Herguido and I. Kumakiri and S. Araki and Miguel Menéndez},
url = {https://www.sciencedirect.com/science/article/pii/S0920586120301310},
doi = {10.1016/j.cattod.2020.03.014},
issn = {0920-5861},
year = {2021},
date = {2021-03-01},
urldate = {2021-03-01},
journal = {Catalysis Today},
volume = {364},
pages = {270–275},
series = {Special Issue on the 14th International Conference on Catalysis in Membrane Reactors},
abstract = {A zeolite membrane reactor can be employed for hydrogenation of CO2 to methanol. The removal of water from the reaction environment would increase the reaction rate and the achievable conversion. The separation of water from mixtures containing CO2, hydrogen and water at suitable temperatures for this reaction was tested with several zeolite membranes (zeolite A, mordenite, zeolite T, chabazite and Ti-Chabazite). Zeolite A provided the best H2O/H2 separation factor. Preliminary experiments comparing a traditional reactor and the combination of a traditional reactor with a membrane reactor show that the yield of methanol was improved, in one case being higher than the limit corresponding to the thermodynamic equilibrium in a conventional reactor.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A zeolite membrane reactor can be employed for hydrogenation of CO2 to methanol. The removal of water from the reaction environment would increase the reaction rate and the achievable conversion. The separation of water from mixtures containing CO2, hydrogen and water at suitable temperatures for this reaction was tested with several zeolite membranes (zeolite A, mordenite, zeolite T, chabazite and Ti-Chabazite). Zeolite A provided the best H2O/H2 separation factor. Preliminary experiments comparing a traditional reactor and the combination of a traditional reactor with a membrane reactor show that the yield of methanol was improved, in one case being higher than the limit corresponding to the thermodynamic equilibrium in a conventional reactor.
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
In: Fuel, vol. 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
In: Fuel, vol. 283, 2021, ISSN: 00162361.
@article{Colom-Diaz2021bb,
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.
Manyà, Joan Josep; Alvira, Darío; Videgain, María; Duman, Gozde; Yanik, Jale
Assessing the Importance of Pyrolysis Process Conditions and Feedstock Type on the Combustion Performance of Agricultural-Residue-Derived Chars Journal Article
In: Energy & Fuels, 2021.
@article{Manya2021,
title = {Assessing the Importance of Pyrolysis Process Conditions and Feedstock Type on the Combustion Performance of Agricultural-Residue-Derived Chars},
author = {Joan Josep Manyà and Darío Alvira and María Videgain and Gozde Duman and Jale Yanik},
url = {https://dx.doi.org/10.1021/acs.energyfuels.0c04180},
doi = {10.1021/acs.energyfuels.0c04180},
year = {2021},
date = {2021-01-01},
journal = {Energy & Fuels},
publisher = {American Chemical Society},
abstract = {The combustion performance of chars derived from vine shoots, wheat straw, and corn stover was investigated to assess the influence of both the biomass precursor and pyrolysis operating conditions. Chars were produced through slow pyrolysis at different peak temperatures (350 and 500 °C), pressures (0.1 and 0.5 MPa), and residence times of the vapor phase (50 and 150 s). From the thermogravimetric curves obtained under air, the combustion performance index (S) was calculated for each char. Apparent kinetics were also estimated using the Coats−Redfern method and assuming an F3/2 reaction model. Results show that the combustion patterns of chars were more influenced by the type of feedstock than by the pyrolysis conditions. Corn stover appeared to be the most interesting feedstock in order to produce chars with tuned reactivity. Results from partial least-squares (PLS) regression revealed that the most important factors affecting S were the contents of potassium (negative effect) and cellulose (positive effect) in the original biomass.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The combustion performance of chars derived from vine shoots, wheat straw, and corn stover was investigated to assess the influence of both the biomass precursor and pyrolysis operating conditions. Chars were produced through slow pyrolysis at different peak temperatures (350 and 500 °C), pressures (0.1 and 0.5 MPa), and residence times of the vapor phase (50 and 150 s). From the thermogravimetric curves obtained under air, the combustion performance index (S) was calculated for each char. Apparent kinetics were also estimated using the Coats−Redfern method and assuming an F3/2 reaction model. Results show that the combustion patterns of chars were more influenced by the type of feedstock than by the pyrolysis conditions. Corn stover appeared to be the most interesting feedstock in order to produce chars with tuned reactivity. Results from partial least-squares (PLS) regression revealed that the most important factors affecting S were the contents of potassium (negative effect) and cellulose (positive effect) in the original biomass.
Benés, Mario; Pozo, Guillermo; Abián, María; Millera, Ángela; Bilbao, Rafael; Alzueta, María U
Experimental Study of the Pyrolysis of NH3under Flow Reactor Conditions Journal Article
In: Energy and Fuels, 2021, ISSN: 15205029.
@article{Benes2021,
title = {Experimental Study of the Pyrolysis of NH3under Flow Reactor Conditions},
author = {Mario Benés and Guillermo Pozo and María Abián and Ángela Millera and Rafael Bilbao and María U Alzueta},
url = {https://dx.doi.org/10.1021/acs.energyfuels.0c03387},
doi = {10.1021/acs.energyfuels.0c03387},
issn = {15205029},
year = {2021},
date = {2021-01-01},
journal = {Energy and Fuels},
publisher = {American Chemical Society},
abstract = {The possibility of using ammonia (NH3), as a fuel and as an energy carrier with low pollutant emissions, can contribute to the transition to a low-carbon economy. To use ammonia as fuel, knowledge about the NH3 conversion is desired. In particular, the conversion of ammonia under pyrolysis conditions could be determinant in the description of its combustion mechanism. In this work, pyrolysis experiments of ammonia have been performed in both a quartz tubular flow reactor (900-1500 K) and a non-porous alumina tubular flow reactor (900-1800 K) using Ar or N2 as bath gas. An experimental study of the influence of the reactor material (quartz or alumina), the bulk gas (N2 or Ar), the ammonia inlet concentration (1000 and 10a 000 ppm), and the gas residence time [2060/T (K)-8239/T (K) s] on the pyrolysis process has been performed. After the reaction, the resulting compounds (NH3, H2, and N2) are analyzed in a gas chromatograph/thermal conductivity detector chromatograph and an infrared continuous analyzer. Results show that H2 and N2 are the main products of the thermal decomposition of ammonia. Under the conditions of the present work, differences between working in a quartz or non-porous alumina reactor are not significant under pyrolysis conditions for temperatures lower than 1400 K. Neither the bath gas nor the ammonia inlet concentration influence the ammonia conversion values. For a given temperature and under all conditions studied, conversion of ammonia increases with an increasing gas residence time, which results into a narrower temperature window for NH3 conversion.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The possibility of using ammonia (NH3), as a fuel and as an energy carrier with low pollutant emissions, can contribute to the transition to a low-carbon economy. To use ammonia as fuel, knowledge about the NH3 conversion is desired. In particular, the conversion of ammonia under pyrolysis conditions could be determinant in the description of its combustion mechanism. In this work, pyrolysis experiments of ammonia have been performed in both a quartz tubular flow reactor (900-1500 K) and a non-porous alumina tubular flow reactor (900-1800 K) using Ar or N2 as bath gas. An experimental study of the influence of the reactor material (quartz or alumina), the bulk gas (N2 or Ar), the ammonia inlet concentration (1000 and 10a 000 ppm), and the gas residence time [2060/T (K)-8239/T (K) s] on the pyrolysis process has been performed. After the reaction, the resulting compounds (NH3, H2, and N2) are analyzed in a gas chromatograph/thermal conductivity detector chromatograph and an infrared continuous analyzer. Results show that H2 and N2 are the main products of the thermal decomposition of ammonia. Under the conditions of the present work, differences between working in a quartz or non-porous alumina reactor are not significant under pyrolysis conditions for temperatures lower than 1400 K. Neither the bath gas nor the ammonia inlet concentration influence the ammonia conversion values. For a given temperature and under all conditions studied, conversion of ammonia increases with an increasing gas residence time, which results into a narrower temperature window for NH3 conversion.
Lozano, Pablo; Simón, Ana I; García, Lucía; Ruiz, Joaquín; Oliva, Miriam; Arauzo, Jesús
Influence of the Ni-Co/Al-Mg catalyst loading in the continuous aqueous phase reforming of the bio-oil aqueous fraction Journal Article
In: Processes, vol. 9, no. 1, pp. 1–17, 2021, ISSN: 22279717.
@article{Lozano2021,
title = {Influence of the Ni-Co/Al-Mg catalyst loading in the continuous aqueous phase reforming of the bio-oil aqueous fraction},
author = {Pablo Lozano and Ana I Simón and Lucía García and Joaquín Ruiz and Miriam Oliva and Jesús Arauzo},
url = {https://doi.org/10.3390/pr9010081},
doi = {10.3390/pr9010081},
issn = {22279717},
year = {2021},
date = {2021-01-01},
journal = {Processes},
volume = {9},
number = {1},
pages = {1--17},
publisher = {MDPI AG},
abstract = {The effect of catalyst loading in the Aqueous Phase Reforming (APR) of bio-oil aqueous fraction has been studied with a Ni-Co/Al-Mg coprecipitated catalyst. Because of the high content of water in the bio-oil aqueous fraction, APR could be a useful process to convert this fraction into valuable products. Experiments of APR with continuous feeding of aqueous solution of acetol, butanol and acetic acid as the only compound, together with a simulated and a real aqueous fraction of bio-oil, were carried out. Liquid products in the liquid effluent of the APR model compounds were quantified and the reaction pathways were revised. The increase of catalyst loading produced an increase of gas production and a gas with higher alkanes content. Acetol was the compound with the highest reactivity while the conversion of acetic acid was very low. The presence of acetic acid in the feed caused catalyst deactivation.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The effect of catalyst loading in the Aqueous Phase Reforming (APR) of bio-oil aqueous fraction has been studied with a Ni-Co/Al-Mg coprecipitated catalyst. Because of the high content of water in the bio-oil aqueous fraction, APR could be a useful process to convert this fraction into valuable products. Experiments of APR with continuous feeding of aqueous solution of acetol, butanol and acetic acid as the only compound, together with a simulated and a real aqueous fraction of bio-oil, were carried out. Liquid products in the liquid effluent of the APR model compounds were quantified and the reaction pathways were revised. The increase of catalyst loading produced an increase of gas production and a gas with higher alkanes content. Acetol was the compound with the highest reactivity while the conversion of acetic acid was very low. The presence of acetic acid in the feed caused catalyst deactivation.
Xu, Minghou; Glarborg, Peter; Alzueta, María U; Aldén, Marcus; Wu, Hongwei
Special Issue in Memory of Professor Mário Costa Journal Article
In: Energy & Fuels, 2021.
@article{Xu2021,
title = {Special Issue in Memory of Professor Mário Costa},
author = {Minghou Xu and Peter Glarborg and María U Alzueta and Marcus Aldén and Hongwei Wu},
url = {https://pubs.acs.org/doi/full/10.1021/acs.energyfuels.1c00826},
doi = {10.1021/ACS.ENERGYFUELS.1C00826},
year = {2021},
date = {2021-01-01},
journal = {Energy & Fuels},
publisher = {American Chemical Society},
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
In: Fuel, vol. 283, pp. 119258, 2021, ISSN: 0016-2361.
@article{Colom-Diaz2021bc,
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 = {0016-2361},
year = {2021},
date = {2021-01-01},
journal = {Fuel},
volume = {283},
pages = {119258},
publisher = {Elsevier},
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.
Alzueta, María U; Guerrero, Marta; Millera, Ángela; Marshall, Paul; Glarborg, Peter
Experimental and kinetic modeling study of oxidation of acetonitrile Journal Article
In: Proceedings of the Combustion Institute, vol. 38, no. 1, pp. 575–583, 2021, ISSN: 1540-7489.
@article{Alzueta2021a,
title = {Experimental and kinetic modeling study of oxidation of acetonitrile},
author = {María U Alzueta and Marta Guerrero and Ángela Millera and Paul Marshall and Peter Glarborg},
doi = {10.1016/J.PROCI.2020.07.043},
issn = {1540-7489},
year = {2021},
date = {2021-01-01},
journal = {Proceedings of the Combustion Institute},
volume = {38},
number = {1},
pages = {575--583},
publisher = {Elsevier},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Fonts, Isabel; Atienza-Martínez, María; Carstensen, Hans-Heinrich; Benés, Mario; Pires, Anamaria Paiva Pinheiro; Garcia-Perez, Manuel; Bilbao, Rafael
Thermodynamic and Physical Property Estimation of Compounds Derived from the Fast Pyrolysis of Lignocellulosic Materials Journal Article
In: Energy & Fuels, 2021.
@article{Fonts2021,
title = {Thermodynamic and Physical Property Estimation of Compounds Derived from the Fast Pyrolysis of Lignocellulosic Materials},
author = {Isabel Fonts and María Atienza-Martínez and Hans-Heinrich Carstensen and Mario Benés and Anamaria Paiva Pinheiro Pires and Manuel Garcia-Perez and Rafael Bilbao},
url = {https://pubs.acs.org/doi/full/10.1021/acs.energyfuels.1c01709},
doi = {10.1021/ACS.ENERGYFUELS.1C01709},
year = {2021},
date = {2021-01-01},
journal = {Energy & Fuels},
publisher = {American Chemical Society},
abstract = {The development of biomass pyrolysis oil refineries is a very promising path for the production of biofuels and bioproducts from lignocellulosic materials. Given that bio-oil is a complex mixture o...},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The development of biomass pyrolysis oil refineries is a very promising path for the production of biofuels and bioproducts from lignocellulosic materials. Given that bio-oil is a complex mixture o…
Afailal, Zainab; Gil-Lalaguna, Noemí; Torrijos, María Teresa; Gonzalo, Alberto; Arauzo, Jesús; Sánchez, José Luis
Antioxidant Additives Produced from Argan Shell Lignin Depolymerization Journal Article
In: Energy & Fuels, 2021.
@article{Afailal2021,
title = {Antioxidant Additives Produced from Argan Shell Lignin Depolymerization},
author = {Zainab Afailal and Noemí Gil-Lalaguna and María Teresa Torrijos and Alberto Gonzalo and Jesús Arauzo and José Luis Sánchez},
url = {https://pubs.acs.org/doi/abs/10.1021/acs.energyfuels.1c01705},
doi = {10.1021/ACS.ENERGYFUELS.1C01705},
year = {2021},
date = {2021-01-01},
journal = {Energy & Fuels},
publisher = {American Chemical Society},
abstract = {The present work summarizes the results of an experimental study focused on producing antioxidant additives for biofuels from argan shell lignin. The generation of this waste has noticeably increas...},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The present work summarizes the results of an experimental study focused on producing antioxidant additives for biofuels from argan shell lignin. The generation of this waste has noticeably increas…
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
In: Proceedings of the Combustion Institute, vol. 38, no. 1, pp. 631–640, 2021, ISSN: 1540-7489.
@article{Tran2021,
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 = {1540-7489},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Proceedings of the Combustion Institute},
volume = {38},
number = {1},
pages = {631--640},
publisher = {Elsevier},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Robaina, Boris Abel Ramos; Reyes, Yanet Guerra; Trujillo, Leonardo Aguiar; Montesino, Francisco Márquez; Pedroso, Daniel Travieso; Machin, Einara Blanco; Machín, Adrian Blanco; Pascual, Rodrigo; Arauzo, Jesús; Gonzalo, Alberto; Sánchez, José Luis
Assessment of fluidized bed gasification of grapefruit solid waste Journal Article
In: Bioresource Technology Reports, vol. 15, no. July, 2021, ISSN: 2589014X.
@article{Robaina2021,
title = {Assessment of fluidized bed gasification of grapefruit solid waste},
author = {Boris Abel Ramos Robaina and Yanet Guerra Reyes and Leonardo Aguiar Trujillo and Francisco Márquez Montesino and Daniel Travieso Pedroso and Einara Blanco Machin and Adrian Blanco Machín and Rodrigo Pascual and Jesús Arauzo and Alberto Gonzalo and José Luis Sánchez},
doi = {10.1016/j.biteb.2021.100782},
issn = {2589014X},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Bioresource Technology Reports},
volume = {15},
number = {July},
abstract = {This work assesses the effects of various process temperatures (700, 750, and 800 °C) and equivalence ratio (0.25; 0.30 and 0.35) on gasification of grapefruit (Citrus x paradisi) solid waste (GSW) in a fluidized bed reactor. The experimental results permit the construction and fit tridimensional chart to assess the studied main output variables' behavior for the simultaneous variation of equivalence ratio and process temperature. The better producer gas composition for the grapefruit solid waste gasification was obtained for a process temperature of 800 °C and 0.25 equivalence ratio; the gas yields around 67%, with LHV of 4389 kJ/Nm3, within the spectrum of values reported for other lignocellulosic residues. According to the obtained study results, GSW presents a valuable renewable energy resource for agroindustry. For operation parameters assessed, could be potentially produced 3.49 GJ of thermal energy per ton of GSW gasified.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This work assesses the effects of various process temperatures (700, 750, and 800 °C) and equivalence ratio (0.25; 0.30 and 0.35) on gasification of grapefruit (Citrus x paradisi) solid waste (GSW) in a fluidized bed reactor. The experimental results permit the construction and fit tridimensional chart to assess the studied main output variables’ behavior for the simultaneous variation of equivalence ratio and process temperature. The better producer gas composition for the grapefruit solid waste gasification was obtained for a process temperature of 800 °C and 0.25 equivalence ratio; the gas yields around 67%, with LHV of 4389 kJ/Nm3, within the spectrum of values reported for other lignocellulosic residues. According to the obtained study results, GSW presents a valuable renewable energy resource for agroindustry. For operation parameters assessed, could be potentially produced 3.49 GJ of thermal energy per ton of GSW gasified.
González‐González, Reyna Berenice; Ruiz‐Gómez, Nadia; Gea, Gloria; Vázquez‐Pinon, Matias; Martinez‐Chapa, Sergio O.; Caballero, Porfirio; Mendoza, Alberto
Valorization of waste tires by pyrolysis and activation processes Journal Article
In: Applied Sciences (Switzerland), vol. 11, no. 14, 2021, ISSN: 20763417.
@article{Gonzalezgonzalez2021,
title = {Valorization of waste tires by pyrolysis and activation processes},
author = {Reyna Berenice González‐González and Nadia Ruiz‐Gómez and Gloria Gea and Matias Vázquez‐Pinon and Sergio O. Martinez‐Chapa and Porfirio Caballero and Alberto Mendoza},
doi = {10.3390/app11146342},
issn = {20763417},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Applied Sciences (Switzerland)},
volume = {11},
number = {14},
abstract = {The problems related to the increase in the generation of discarded tires demonstrate the need for profitable, efficient, cost‐effective, and sustainable processes for their waste management. In particular, the valorization of pyrolytic solids for energy storage applications is of interest. In this study, four processes were performed: (1) pyrolysis; (2) chemical activation and pyrolysis; (3) pyrolysis and physical activation; and (4) chemical activation, pyrolysis, and physical activation. The process consisting of chemical activation, pyrolysis, and physical activation yielded 52% solid material with the highest electrical conductivity (2.43 $Ømega$–1 cm–1) and a surface area of 339 m2/g with an average pore size of 3.6 nm. In addition, it was found that pore size had a greater effect on the conductivity than surface area. Liquid and gas fraction compositions were modified by the presence of chemical activation: aromatization reactions were favored, and limonene was not observed in the liquid fraction, while an increase on the CH4 concentration caused an increment in the heating value of the gas fraction. It was demonstrated that chemical and physical activation enhance the properties of the pyrolytic solid product derived from waste tires that make it suitable for the partial substitution of materials for electric energy storage applications.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The problems related to the increase in the generation of discarded tires demonstrate the need for profitable, efficient, cost‐effective, and sustainable processes for their waste management. In particular, the valorization of pyrolytic solids for energy storage applications is of interest. In this study, four processes were performed: (1) pyrolysis; (2) chemical activation and pyrolysis; (3) pyrolysis and physical activation; and (4) chemical activation, pyrolysis, and physical activation. The process consisting of chemical activation, pyrolysis, and physical activation yielded 52% solid material with the highest electrical conductivity (2.43 $Ømega$–1 cm–1) and a surface area of 339 m2/g with an average pore size of 3.6 nm. In addition, it was found that pore size had a greater effect on the conductivity than surface area. Liquid and gas fraction compositions were modified by the presence of chemical activation: aromatization reactions were favored, and limonene was not observed in the liquid fraction, while an increase on the CH4 concentration caused an increment in the heating value of the gas fraction. It was demonstrated that chemical and physical activation enhance the properties of the pyrolytic solid product derived from waste tires that make it suitable for the partial substitution of materials for electric energy storage applications.
Moreira, Rui; Bimbela, Fernando; Gandía, Luis M.; Ferreira, Abel; Sánchez, José Luis; Portugal, António
Oxidative steam reforming of glycerol. A review Journal Article
In: Renewable and Sustainable Energy Reviews, vol. 148, 2021, ISSN: 18790690.
@article{Moreira2021,
title = {Oxidative steam reforming of glycerol. A review},
author = {Rui Moreira and Fernando Bimbela and Luis M. Gandía and Abel Ferreira and José Luis Sánchez and António Portugal},
doi = {10.1016/j.rser.2021.111299},
issn = {18790690},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Renewable and Sustainable Energy Reviews},
volume = {148},
abstract = {This review article presents the state-of-the-art on the catalytic oxidative steam reforming (OSR) of glycerol to produce syngas. Concerning the different technologies proposed for the catalytic OSR of glycerol, the following key points can be highlighted: (1) the robustness is much higher than other reforming technologies, (2) several catalysts can work with low deactivation, some of which can recover almost full activity by suitable regeneration, (3) syngas production by catalytic OSR of glycerin is higher than with concurrent technologies, (4) their scaling-up remains an unrealized task, (5) the thermodynamics of the process has been sufficiently covered in the literature, (6) there is a significant lack of kinetic and mechanistic studies that could help gaining deeper insight on the process, (7) novel concepts and reactor designs must be proposed for their development at larger scales, (8) new catalyst formulations must be developed for attaining higher resistance against oxidation and (9) process intensification could help developing them at larger scales.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This review article presents the state-of-the-art on the catalytic oxidative steam reforming (OSR) of glycerol to produce syngas. Concerning the different technologies proposed for the catalytic OSR of glycerol, the following key points can be highlighted: (1) the robustness is much higher than other reforming technologies, (2) several catalysts can work with low deactivation, some of which can recover almost full activity by suitable regeneration, (3) syngas production by catalytic OSR of glycerin is higher than with concurrent technologies, (4) their scaling-up remains an unrealized task, (5) the thermodynamics of the process has been sufficiently covered in the literature, (6) there is a significant lack of kinetic and mechanistic studies that could help gaining deeper insight on the process, (7) novel concepts and reactor designs must be proposed for their development at larger scales, (8) new catalyst formulations must be developed for attaining higher resistance against oxidation and (9) process intensification could help developing them at larger scales.
Moreira, Rui; Bimbela, Fernando; Gil-Lalaguna, Noemí; Sánchez, José Luis; Portugal, António
Clean syngas production by gasification of lignocellulosic char: State of the art and future prospects Journal Article
In: Journal of Industrial and Engineering Chemistry, vol. 101, pp. 1–20, 2021, ISSN: 22345957.
@article{Moreira2021b,
title = {Clean syngas production by gasification of lignocellulosic char: State of the art and future prospects},
author = {Rui Moreira and Fernando Bimbela and Noemí Gil-Lalaguna and José Luis Sánchez and António Portugal},
doi = {10.1016/j.jiec.2021.05.040},
issn = {22345957},
year = {2021},
date = {2021-01-01},
journal = {Journal of Industrial and Engineering Chemistry},
volume = {101},
pages = {1--20},
abstract = {Using lignocellulosic char instead of the original biomass avoids the need for costly cleaning and conditioning stages of the producer gasification gas. However, lignocellulosic char gasification has been less extensively studied than gasification of lignocellulosic biomass, and a review of published works on this topic was missing. In this review the present status of char gasification technologies and their future prospects are critically discussed, including possible research opportunities. To date, most studies on char gasification have been performed in thermogravimetric analyzers (TGA) or TGA-like experimental setups. The major setback of TGA and TGA-like equipment is that they do not mimic the actual reaction conditions occurring in gasification reactors, which impedes a direct extrapolation of the findings during the scale-up of different gasification technologies. For this reason, in this literature review focus was put on studies undertaken in industrially relevant reactors, both in batch and continuous configurations. Overall, char gasification can be deemed a valid alternative for clean syngas production, contributing to an integral valorization of lignocellulosic residues within different biorefinery schemes. Of these, process intensification by microwave heating offers interesting opportunities for research and scaling-up, though efforts must be directed toward developing continuous microwave-assisted gasification processes.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Using lignocellulosic char instead of the original biomass avoids the need for costly cleaning and conditioning stages of the producer gasification gas. However, lignocellulosic char gasification has been less extensively studied than gasification of lignocellulosic biomass, and a review of published works on this topic was missing. In this review the present status of char gasification technologies and their future prospects are critically discussed, including possible research opportunities. To date, most studies on char gasification have been performed in thermogravimetric analyzers (TGA) or TGA-like experimental setups. The major setback of TGA and TGA-like equipment is that they do not mimic the actual reaction conditions occurring in gasification reactors, which impedes a direct extrapolation of the findings during the scale-up of different gasification technologies. For this reason, in this literature review focus was put on studies undertaken in industrially relevant reactors, both in batch and continuous configurations. Overall, char gasification can be deemed a valid alternative for clean syngas production, contributing to an integral valorization of lignocellulosic residues within different biorefinery schemes. Of these, process intensification by microwave heating offers interesting opportunities for research and scaling-up, though efforts must be directed toward developing continuous microwave-assisted gasification processes.
Tran, Luc Sy; Carstensen, Hans-Heinrich; Lamoureux, Nathalie; Foo, Kae Ken; Gosselin, Sylvie; Bakali, Abderrahman El; Gasnot, Laurent; Desgroux, Pascale
Exploring the Flame Chemistry of C5 Tetrahydrofuranic Biofuels: Tetrahydrofurfuryl Alcohol and 2-Methyltetrahydrofuran Journal Article
In: Energy and Fuels, vol. 35, no. 22, pp. 18699–18715, 2021, ISSN: 15205029.
@article{Tran2021b,
title = {Exploring the Flame Chemistry of C5 Tetrahydrofuranic Biofuels: Tetrahydrofurfuryl Alcohol and 2-Methyltetrahydrofuran},
author = {Luc Sy Tran and Hans-Heinrich Carstensen and Nathalie Lamoureux and Kae Ken Foo and Sylvie Gosselin and Abderrahman El Bakali and Laurent Gasnot and Pascale Desgroux},
doi = {10.1021/acs.energyfuels.1c01949},
issn = {15205029},
year = {2021},
date = {2021-01-01},
urldate = {2021-01-01},
journal = {Energy and Fuels},
volume = {35},
number = {22},
pages = {18699--18715},
abstract = {Recently, the combustion chemistry of tetrahydrofurfuryl alcohol (THFA), a potential biofuel, was investigated in a stoichiometric 20 mol % THFA/methane co-fueled premixed flame at 5.3 kPa by our group (Tran, L.-S.; Carstensen, H.-H.; Foo, K. K.; Lamoureux, N.; Gosselin, S.; Gasnot, L.; El-Bakali, A.; Desgroux, P. Experimental and modeling study of the high-temperature combustion chemistry of tetrahydrofurfuryl alcohol. Proc. Combust. Inst. 2021, 38, 631-640, 10.1016/j.proci.2020.07.057). With regard to this, we continue to further explore the combustion chemistry of this biofuel to understand the influence of THFA-doping amounts on the flame chemistry of its mixture with methane and the impact of the alcohol function of THFA on the product spectrum compared to its non-alcoholic fuel counterpart, i.e., 2-methyltetrahydrofuran (MTHF). To accomplish the above said objective, a methane flame, a 10% THFA/methane flame, and a 20% MTHF/methane flame were additionally analyzed at similar conditions using gas chromatography for quantitative species detection and NO laser-induced fluorescence thermometry. More than 40 species (reactants, CO, CO2, H2O, H2, and about 14 hydrocarbons as well as 26 oxygenated intermediates up to 5 carbon atoms) were quantified for each doped biofuel flame. The product distributions and consumption pathways of THFA are similar for the 10 and 20% THFA-doped flames. The maximum yields of most products increase linearly with the amount of doped THFA. However, some species do not follow this trend, indicating interaction chemistry between methane and THFA, which is found to be mainly caused by the reaction of the methyl radical. The difference in the chemical structure in THFA and MTHF has no notable impact on the mole fractions of CO, CO2, H2O, and H2, but significant differences exist for the yields of intermediate species. The doped THFA flame produces more aldehydes, alcohols, and ethers but forms clearly less ketones and hydrocarbons. A slightly upgraded version of our previous kinetic model reproduces most experimental data well and is able to explain the observed differences in intermediate production.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Recently, the combustion chemistry of tetrahydrofurfuryl alcohol (THFA), a potential biofuel, was investigated in a stoichiometric 20 mol % THFA/methane co-fueled premixed flame at 5.3 kPa by our group (Tran, L.-S.; Carstensen, H.-H.; Foo, K. K.; Lamoureux, N.; Gosselin, S.; Gasnot, L.; El-Bakali, A.; Desgroux, P. Experimental and modeling study of the high-temperature combustion chemistry of tetrahydrofurfuryl alcohol. Proc. Combust. Inst. 2021, 38, 631-640, 10.1016/j.proci.2020.07.057). With regard to this, we continue to further explore the combustion chemistry of this biofuel to understand the influence of THFA-doping amounts on the flame chemistry of its mixture with methane and the impact of the alcohol function of THFA on the product spectrum compared to its non-alcoholic fuel counterpart, i.e., 2-methyltetrahydrofuran (MTHF). To accomplish the above said objective, a methane flame, a 10% THFA/methane flame, and a 20% MTHF/methane flame were additionally analyzed at similar conditions using gas chromatography for quantitative species detection and NO laser-induced fluorescence thermometry. More than 40 species (reactants, CO, CO2, H2O, H2, and about 14 hydrocarbons as well as 26 oxygenated intermediates up to 5 carbon atoms) were quantified for each doped biofuel flame. The product distributions and consumption pathways of THFA are similar for the 10 and 20% THFA-doped flames. The maximum yields of most products increase linearly with the amount of doped THFA. However, some species do not follow this trend, indicating interaction chemistry between methane and THFA, which is found to be mainly caused by the reaction of the methyl radical. The difference in the chemical structure in THFA and MTHF has no notable impact on the mole fractions of CO, CO2, H2O, and H2, but significant differences exist for the yields of intermediate species. The doped THFA flame produces more aldehydes, alcohols, and ethers but forms clearly less ketones and hydrocarbons. A slightly upgraded version of our previous kinetic model reproduces most experimental data well and is able to explain the observed differences in intermediate 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
In: Applied Energy, vol. 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.