2007
Artículos de revista
Liesa, Fernando; Alzueta, María U; Millera, Ángela; Bilbao, Rafael
Influence of reactant mixing in a laminar flow reactor: The case of gas reburning. 2. Modelling study Artículo de revista
En: Industrial and Engineering Chemistry Research, vol. 46, no 11, pp. 3528–3537, 2007, ISSN: 08885885.
@article{Liesa2007b,
title = {Influence of reactant mixing in a laminar flow reactor: The case of gas reburning. 2. Modelling study},
author = {Fernando Liesa and María U Alzueta and Ángela Millera and Rafael Bilbao},
doi = {10.1021/ie060944i},
issn = {08885885},
year = {2007},
date = {2007-05-01},
journal = {Industrial and Engineering Chemistry Research},
volume = {46},
number = {11},
pages = {3528--3537},
abstract = {A theoretical study of the influence of mixing on reburning under laminar flow non-premixed conditions has been performed. Two models with a different level of detail of the fluid dynamics description have been developed and adapted. Models have been validated against experimental results. The models are able to reproduce the experimental trends of the influence of the studied variables: temperature, stoichiometry, velocity ratio between the streams, and reactant feeding configuration. Modeling and experimental results have been compared with plug-flow reactor (PFR) results, showing significant differences. Reactant injection mode involves a change in local stoichiometry and residence time distribution in the reactor, which seems to be the main influencing factor. For low temperatures, a higher NO reduction is obtained when local fuel-lean conditions have a longer residence time. For high temperatures, a higher NO reduction is obtained when local fuel-rich conditions have a longer residence time. textcopyright 2007 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A theoretical study of the influence of mixing on reburning under laminar flow non-premixed conditions has been performed. Two models with a different level of detail of the fluid dynamics description have been developed and adapted. Models have been validated against experimental results. The models are able to reproduce the experimental trends of the influence of the studied variables: temperature, stoichiometry, velocity ratio between the streams, and reactant feeding configuration. Modeling and experimental results have been compared with plug-flow reactor (PFR) results, showing significant differences. Reactant injection mode involves a change in local stoichiometry and residence time distribution in the reactor, which seems to be the main influencing factor. For low temperatures, a higher NO reduction is obtained when local fuel-lean conditions have a longer residence time. For high temperatures, a higher NO reduction is obtained when local fuel-rich conditions have a longer residence time. textcopyright 2007 American Chemical Society.
Mastral, José Francisco; Berrueco, César; Ceamanos, Jesús
Modelling of the pyrolysis of high density polyethylene. Product distribution in a fluidized bed reactor Artículo de revista
En: Journal of Analytical and Applied Pyrolysis, vol. 79, no 1-2 SPEC. ISS., pp. 313–322, 2007, ISSN: 01652370.
@article{Mastral2007a,
title = {Modelling of the pyrolysis of high density polyethylene. Product distribution in a fluidized bed reactor},
author = {José Francisco Mastral and César Berrueco and Jesús Ceamanos},
doi = {10.1016/j.jaap.2006.10.018},
issn = {01652370},
year = {2007},
date = {2007-05-01},
journal = {Journal of Analytical and Applied Pyrolysis},
volume = {79},
number = {1-2 SPEC. ISS.},
pages = {313--322},
publisher = {Elsevier},
abstract = {The increase in the generation of plastic wastes has triggered the study of different alternatives for their recovery. Pyrolysis appears to be an interesting alternative for the treatment of mixtures of different plastics. The development of a model that simulates polyethylene pyrolysis (one of the most abundant plastics) has been considered interesting in order to analyse the influence of the operation variables on the behaviour of the system. The existing models predict the generation of the main products, paraffins, olefins and diolefins, but not the influence of temperature and residence time on the product distribution. Neither is the formation of aromatics and polyaromatics included. The main objective of this work is the formulation and development of a model that predicts the product distribution obtained in the pyrolysis of polyethylene. In order to do this a mechanistic model has been developed based on a radical mechanism. This model uses a small number of elementary kinetic steps, including initiation, $beta$-scission, H-abstraction, aromatization and radical combination. The results obtained have been validated with experimental results obtained in a fluidized bed reactor in which the pyrolysis process has been studied at different temperatures (640-700 °C) and residence times (0.8-2.6 s). The results show that the trends experimentally observed for the different temperatures and residence times studied are predicted. textcopyright 2006 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The increase in the generation of plastic wastes has triggered the study of different alternatives for their recovery. Pyrolysis appears to be an interesting alternative for the treatment of mixtures of different plastics. The development of a model that simulates polyethylene pyrolysis (one of the most abundant plastics) has been considered interesting in order to analyse the influence of the operation variables on the behaviour of the system. The existing models predict the generation of the main products, paraffins, olefins and diolefins, but not the influence of temperature and residence time on the product distribution. Neither is the formation of aromatics and polyaromatics included. The main objective of this work is the formulation and development of a model that predicts the product distribution obtained in the pyrolysis of polyethylene. In order to do this a mechanistic model has been developed based on a radical mechanism. This model uses a small number of elementary kinetic steps, including initiation, $beta$-scission, H-abstraction, aromatization and radical combination. The results obtained have been validated with experimental results obtained in a fluidized bed reactor in which the pyrolysis process has been studied at different temperatures (640-700 °C) and residence times (0.8-2.6 s). The results show that the trends experimentally observed for the different temperatures and residence times studied are predicted. textcopyright 2006 Elsevier B.V. All rights reserved.
Bimbela, Fernando; Oliva, Miriam; Ruiz, Joaquín; García, Lucía; Arauzo, Jesús
Hydrogen production by catalytic steam reforming of acetic acid, a model compound of biomass pyrolysis liquids Artículo de revista
En: Journal of Analytical and Applied Pyrolysis, vol. 79, no 1-2 SPEC. ISS., pp. 112–120, 2007, ISSN: 01652370.
@article{Bimbela2007,
title = {Hydrogen production by catalytic steam reforming of acetic acid, a model compound of biomass pyrolysis liquids},
author = {Fernando Bimbela and Miriam Oliva and Joaquín Ruiz and Lucía García and Jesús Arauzo},
doi = {10.1016/j.jaap.2006.11.006},
issn = {01652370},
year = {2007},
date = {2007-05-01},
journal = {Journal of Analytical and Applied Pyrolysis},
volume = {79},
number = {1-2 SPEC. ISS.},
pages = {112--120},
publisher = {Elsevier},
abstract = {An environmentally friendly and cost-competitive way of producing hydrogen is the catalytic steam reforming of biomass pyrolysis liquids, known as bio-oil, which can be separated into two fractions: ligninic and aqueous. Acetic acid has been identified as one of the major organic acids present in the latter, and catalytic steam reforming has been studied for this model compound. Three different Ni coprecipitated catalysts have been prepared with varying nickel content (23, 28 and 33% expressed as a Ni/(Ni + Al) relative at.% of nickel). Several parameters have been analysed using a microscale fixed-bed facility: the effect of the catalyst reduction time, the reaction temperature, the catalyst weight/acetic acid flow rate (W/mHAc) ratio, and the effect of the nickel content. The catalyst with 33% Ni content at 650 °C showed no significant enhancement of the hydrogen yield after 2 h of reduction compared to 1 h under the same experimental conditions. Its performance was poorer when reduced for just 0.5 h. For W/mHAc ratios greater than 2.29 g catalyst min/g acetic acid (650 °C, 33% Ni content) no improvement was observed, whereas for values lower than 2.18 g catalyst min/g acetic acid a decrease in product gas yields occurred rapidly. The temperatures studied were 550, 650 and 750 °C. No decrease in product gas yields was observed at 750 °C under the established experimental conditions. Below this temperature, the aforementioned decrease became more important with decreasing temperatures. The catalyst with 28% Ni content performed better than the other two. textcopyright 2006 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
An environmentally friendly and cost-competitive way of producing hydrogen is the catalytic steam reforming of biomass pyrolysis liquids, known as bio-oil, which can be separated into two fractions: ligninic and aqueous. Acetic acid has been identified as one of the major organic acids present in the latter, and catalytic steam reforming has been studied for this model compound. Three different Ni coprecipitated catalysts have been prepared with varying nickel content (23, 28 and 33% expressed as a Ni/(Ni + Al) relative at.% of nickel). Several parameters have been analysed using a microscale fixed-bed facility: the effect of the catalyst reduction time, the reaction temperature, the catalyst weight/acetic acid flow rate (W/mHAc) ratio, and the effect of the nickel content. The catalyst with 33% Ni content at 650 °C showed no significant enhancement of the hydrogen yield after 2 h of reduction compared to 1 h under the same experimental conditions. Its performance was poorer when reduced for just 0.5 h. For W/mHAc ratios greater than 2.29 g catalyst min/g acetic acid (650 °C, 33% Ni content) no improvement was observed, whereas for values lower than 2.18 g catalyst min/g acetic acid a decrease in product gas yields occurred rapidly. The temperatures studied were 550, 650 and 750 °C. No decrease in product gas yields was observed at 750 °C under the established experimental conditions. Below this temperature, the aforementioned decrease became more important with decreasing temperatures. The catalyst with 28% Ni content performed better than the other two. textcopyright 2006 Elsevier B.V. All rights reserved.
Ruiz, Pilar M; Callejas, Alicia; Millera, Ángela; Alzueta, María U; Bilbao, Rafael
Soot formation from C2H2 and C2H4 pyrolysis at different temperatures Artículo de revista
En: Journal of Analytical and Applied Pyrolysis, vol. 79, no 1-2 SPEC. ISS., pp. 244–251, 2007, ISSN: 01652370.
@article{Ruiz2007d,
title = {Soot formation from C2H2 and C2H4 pyrolysis at different temperatures},
author = {Pilar M Ruiz and Alicia Callejas and Ángela Millera and María U Alzueta and Rafael Bilbao},
doi = {10.1016/j.jaap.2006.10.012},
issn = {01652370},
year = {2007},
date = {2007-05-01},
journal = {Journal of Analytical and Applied Pyrolysis},
volume = {79},
number = {1-2 SPEC. ISS.},
pages = {244--251},
publisher = {Elsevier},
abstract = {A study of the pyrolysis of two hydrocarbons, C2H2 and C2H4, at different temperatures has been carried out in order to compare their behaviour in terms of soot and gas yields and gas composition. Pyrolysis experiments have been performed in the same conditions for both hydrocarbons: an inlet hydrocarbon concentration of 15,000 ppmv and a temperature range of 1000-1200 °C. For C2H2 and C2H4 pyrolysis tests, the results present the same trend when increasing the temperature: an increase in soot yield, a decrease in gas yield and a similar evolution of the outlet gases. Comparatively, it can be observed that acetylene is a more sooting hydrocarbon than ethylene for a given temperature. Additionally, the study of soot reactivity with O2 and NO shows that the soot samples obtained from ethylene show a slightly higher reactivity towards O2 and NO than the soot samples formed from acetylene. textcopyright 2006 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A study of the pyrolysis of two hydrocarbons, C2H2 and C2H4, at different temperatures has been carried out in order to compare their behaviour in terms of soot and gas yields and gas composition. Pyrolysis experiments have been performed in the same conditions for both hydrocarbons: an inlet hydrocarbon concentration of 15,000 ppmv and a temperature range of 1000-1200 °C. For C2H2 and C2H4 pyrolysis tests, the results present the same trend when increasing the temperature: an increase in soot yield, a decrease in gas yield and a similar evolution of the outlet gases. Comparatively, it can be observed that acetylene is a more sooting hydrocarbon than ethylene for a given temperature. Additionally, the study of soot reactivity with O2 and NO shows that the soot samples obtained from ethylene show a slightly higher reactivity towards O2 and NO than the soot samples formed from acetylene. textcopyright 2006 Elsevier B.V. All rights reserved.
Ruiz, Pilar M; Villoria, R Guzmán De; Millera, Ángela; Alzueta, María U; Bilbao, Rafael
Influence of the temperature on the properties of the soot formed from C2H2 pyrolysis Artículo de revista
En: Chemical Engineering Journal, vol. 127, no 1-3, pp. 1–9, 2007, ISSN: 13858947.
@article{Ruiz2007b,
title = {Influence of the temperature on the properties of the soot formed from C2H2 pyrolysis},
author = {Pilar M Ruiz and R Guzmán De Villoria and Ángela Millera and María U Alzueta and Rafael Bilbao},
doi = {10.1016/j.cej.2006.09.006},
issn = {13858947},
year = {2007},
date = {2007-03-01},
journal = {Chemical Engineering Journal},
volume = {127},
number = {1-3},
pages = {1--9},
publisher = {Elsevier},
abstract = {The influence of temperature on the properties of the soot formed from C2H2 pyrolysis has been studied. Pyrolysis experiments were carried out in a quartz reactor at 1000-1200 °C, for an inlet C2H2 concentration of 15,000 ppmv. Outlet gases were analysed by gas chromatography and the amount of soot produced measured. The soot samples formed were further characterized using elemental analysis, BET surface area, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and Raman spectroscopy. The soot reactivity towards O2 and NO was studied. Results show that formation temperature is a key parameter in the properties and reactivities of the soot samples formed. The higher the temperature the less reactive the soot, and structural properties support these results. textcopyright 2006 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
The influence of temperature on the properties of the soot formed from C2H2 pyrolysis has been studied. Pyrolysis experiments were carried out in a quartz reactor at 1000-1200 °C, for an inlet C2H2 concentration of 15,000 ppmv. Outlet gases were analysed by gas chromatography and the amount of soot produced measured. The soot samples formed were further characterized using elemental analysis, BET surface area, transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction and Raman spectroscopy. The soot reactivity towards O2 and NO was studied. Results show that formation temperature is a key parameter in the properties and reactivities of the soot samples formed. The higher the temperature the less reactive the soot, and structural properties support these results. textcopyright 2006 Elsevier B.V. All rights reserved.
Aznar, María; González, Ángel E; Manyà, Joan Josep; Sánchez, José Luis; Murillo, María Benita
Understanding the effect of the transition period during the air gasification of dried sewage sludge in a fluidized bed reactor Artículo de revista
En: International Journal of Chemical Reactor Engineering, vol. 5, 2007, ISSN: 15426580.
@article{Aznar2007,
title = {Understanding the effect of the transition period during the air gasification of dried sewage sludge in a fluidized bed reactor},
author = {María Aznar and Ángel E González and Joan Josep Manyà and José Luis Sánchez and María Benita Murillo},
doi = {10.2202/1542-6580.1410},
issn = {15426580},
year = {2007},
date = {2007-01-01},
journal = {International Journal of Chemical Reactor Engineering},
volume = {5},
publisher = {Walter de Gruyter GmbH},
abstract = {Air gasification of dried sewage sludge (DSS) in a fluidized bed has been studied as an effective alternative for the management of this material in a usable way. Nevertheless, one of the major issues in this technology is to deal with the tar formed during the process. To minimize the tar production, it is very important to optimize the operating conditions. In a previous work (Manyà et al, Energy Fuels, Vol. 19, 629-636, 2005) some unexpected results, in which tar production increases with the equivalence ratio, have been obtained. As it has been mentioned in that work, tar production could present unexpected trends while the bed composition changes from sand to a mixture of char and sand. Ashes contained in char have catalytic active metals which could promote gasification reactions. As the char content in the bed increases, the catalytic activity in the reactor could increase too, until the steady state is achieved. The aim of this work is to characterize the non-stationary period and its influence on the overall results obtained from gasification tests. Experiments have been carried out in a laboratory-scale BFB reactor at atmospheric pressure and at a reactor temperature of 1123 K with an equivalent ratio of 30%. Results show that at the beginning of the experiments the tar production was higher, until the steady state is reached. The gasification study has been enhanced with an analysis of tar composition by means of GC/MS and GC/FID. An effect of the transition period has been observed in tar composition also. The nitrogen aromatics percent increased with time whereas the polycyclic aromatic hydrocarbon decreased. Copyright textcopyright 2007 The Berkeley Electronic Press. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Air gasification of dried sewage sludge (DSS) in a fluidized bed has been studied as an effective alternative for the management of this material in a usable way. Nevertheless, one of the major issues in this technology is to deal with the tar formed during the process. To minimize the tar production, it is very important to optimize the operating conditions. In a previous work (Manyà et al, Energy Fuels, Vol. 19, 629-636, 2005) some unexpected results, in which tar production increases with the equivalence ratio, have been obtained. As it has been mentioned in that work, tar production could present unexpected trends while the bed composition changes from sand to a mixture of char and sand. Ashes contained in char have catalytic active metals which could promote gasification reactions. As the char content in the bed increases, the catalytic activity in the reactor could increase too, until the steady state is achieved. The aim of this work is to characterize the non-stationary period and its influence on the overall results obtained from gasification tests. Experiments have been carried out in a laboratory-scale BFB reactor at atmospheric pressure and at a reactor temperature of 1123 K with an equivalent ratio of 30%. Results show that at the beginning of the experiments the tar production was higher, until the steady state is reached. The gasification study has been enhanced with an analysis of tar composition by means of GC/MS and GC/FID. An effect of the transition period has been observed in tar composition also. The nitrogen aromatics percent increased with time whereas the polycyclic aromatic hydrocarbon decreased. Copyright textcopyright 2007 The Berkeley Electronic Press. All rights reserved.
Proceedings Articles
Ramos, Carmen M; Navascués, Ana I; García, Lucía; Bilbao, Rafael
Hydrogen production by catalytic steam reforming of acetol, a model compound of bio-oil Proceedings Article
En: Industrial and Engineering Chemistry Research, pp. 2399–2406, 2007, ISSN: 08885885.
@inproceedings{Ramos2007,
title = {Hydrogen production by catalytic steam reforming of acetol, a model compound of bio-oil},
author = {Carmen M Ramos and Ana I Navascués and Lucía García and Rafael Bilbao},
doi = {10.1021/ie060904e},
issn = {08885885},
year = {2007},
date = {2007-04-01},
booktitle = {Industrial and Engineering Chemistry Research},
volume = {46},
number = {8},
pages = {2399--2406},
abstract = {Hydrogen can be produced by catalytic steam reforming of bio-oil or its fractions. Bio-oil is a complex mixture of a large number of compounds derived from fast pyrolysis of biomass. Acetol has been selected as a model compound. Steam reforming of acetol has been studied in a fluidized bed reactor using coprecipitated Ni-Al catalysts, some promoted with lanthanum and cobalt. Noncatalytic experiments have been performed from 450 to 650°C. Catalytic experiments have been carried out at 600 and 650°C in order to analyze the influence of the catalyst weight/acetol flow rate (W/mAc) ratio on gas yields. The influence of the steam to carbon molar (S/C) ratio and the catalyst composition on gas yields has also been studied. The presence of the catalyst increases H2, CO2, and total gas yields while CH4, CO, and C2 yields decrease. An increase in the S/C ratio at 650°C increases H2, CO2, and total gas yields and carbon conversion to gas. The presence of lanthanum in Ni-Al coprecipitated catalysts increases CH4, CO2, C2, and total gas yields as well as carbon conversion to gas. Ni-Co-Al catalysts present the lowest values of carbon conversion to gas. Hydrogen yields obtained with the catalysts tested follow this sequence: Ni-Al = Ni-Co-Al (Co/Ni = 0.25) > Ni-Co-Al (Co/Ni = 0.025) > Ni-Al-La (4 wt % La2O3) > Ni-Al-La (8 wt % La2O3) > Ni-Al-La (12 wt % La 2O3). textcopyright 2007 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Hydrogen can be produced by catalytic steam reforming of bio-oil or its fractions. Bio-oil is a complex mixture of a large number of compounds derived from fast pyrolysis of biomass. Acetol has been selected as a model compound. Steam reforming of acetol has been studied in a fluidized bed reactor using coprecipitated Ni-Al catalysts, some promoted with lanthanum and cobalt. Noncatalytic experiments have been performed from 450 to 650°C. Catalytic experiments have been carried out at 600 and 650°C in order to analyze the influence of the catalyst weight/acetol flow rate (W/mAc) ratio on gas yields. The influence of the steam to carbon molar (S/C) ratio and the catalyst composition on gas yields has also been studied. The presence of the catalyst increases H2, CO2, and total gas yields while CH4, CO, and C2 yields decrease. An increase in the S/C ratio at 650°C increases H2, CO2, and total gas yields and carbon conversion to gas. The presence of lanthanum in Ni-Al coprecipitated catalysts increases CH4, CO2, C2, and total gas yields as well as carbon conversion to gas. Ni-Co-Al catalysts present the lowest values of carbon conversion to gas. Hydrogen yields obtained with the catalysts tested follow this sequence: Ni-Al = Ni-Co-Al (Co/Ni = 0.25) > Ni-Co-Al (Co/Ni = 0.025) > Ni-Al-La (4 wt % La2O3) > Ni-Al-La (8 wt % La2O3) > Ni-Al-La (12 wt % La 2O3). textcopyright 2007 American Chemical Society.
2006
Artículos de revista
Mastral, José Francisco; Berrueco, César; Gea, M; Ceamanos, Jesús
Catalytic degradation of high density polyethylene over nanocrystalline HZSM-5 zeolite Artículo de revista
En: Polymer Degradation and Stability, vol. 91, no 12, pp. 3330–3338, 2006, ISSN: 01413910.
@article{Mastral2006a,
title = {Catalytic degradation of high density polyethylene over nanocrystalline HZSM-5 zeolite},
author = {José Francisco Mastral and César Berrueco and M Gea and Jesús Ceamanos},
doi = {10.1016/j.polymdegradstab.2006.06.009},
issn = {01413910},
year = {2006},
date = {2006-12-01},
journal = {Polymer Degradation and Stability},
volume = {91},
number = {12},
pages = {3330--3338},
publisher = {Elsevier},
abstract = {High density polyethylene (HDPE) was catalytically degraded using a laboratory fluidised bed reactor in order to obtain high yield of gas fractions at mild temperatures, between 350 and 550 °C. The catalyst used was nanocrystalline HZSM-5 zeolite. High yields of butenes (25%) were found in the gas fractions, which were composed mainly of olefins. Waxes were wholly composed of linear and branched paraffins, with components between C10 and C20. The effects of both temperature and polymer to catalyst ratio on the product yield were studied. Gas conversion was dramatically decreased when the operation temperature was low (below 450 °C) or when the polymer to catalyst ratio was greatly increased (9.2). Gas and wax compositions significantly altered over 500 °C, showing that a part of the HDPE was degraded thermally, increasing the olefin concentration in the waxes. The same variation was observed in the experiments carried out at high polymer to catalyst ratios, obtaining a 50% olefinic concentration in the waxes. The differences observed in product distributions can be attributed to both thermal and catalytic degradations. textcopyright 2006 Elsevier Ltd. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
High density polyethylene (HDPE) was catalytically degraded using a laboratory fluidised bed reactor in order to obtain high yield of gas fractions at mild temperatures, between 350 and 550 °C. The catalyst used was nanocrystalline HZSM-5 zeolite. High yields of butenes (25%) were found in the gas fractions, which were composed mainly of olefins. Waxes were wholly composed of linear and branched paraffins, with components between C10 and C20. The effects of both temperature and polymer to catalyst ratio on the product yield were studied. Gas conversion was dramatically decreased when the operation temperature was low (below 450 °C) or when the polymer to catalyst ratio was greatly increased (9.2). Gas and wax compositions significantly altered over 500 °C, showing that a part of the HDPE was degraded thermally, increasing the olefin concentration in the waxes. The same variation was observed in the experiments carried out at high polymer to catalyst ratios, obtaining a 50% olefinic concentration in the waxes. The differences observed in product distributions can be attributed to both thermal and catalytic degradations. textcopyright 2006 Elsevier Ltd. All rights reserved.
Manyà, Joan Josep; Aznar, María; Sánchez, José Luis; Arauzo, Jesús; Murillo, María Benita
Further experiments on sewage sludge air gasification: Influence of the nonstationary period on the overall results Artículo de revista
En: Industrial and Engineering Chemistry Research, vol. 45, no 21, pp. 7313–7320, 2006, ISSN: 08885885.
@article{Manya2006a,
title = {Further experiments on sewage sludge air gasification: Influence of the nonstationary period on the overall results},
author = {Joan Josep Manyà and María Aznar and José Luis Sánchez and Jesús Arauzo and María Benita Murillo},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ie0605027},
issn = {08885885},
year = {2006},
date = {2006-10-01},
journal = {Industrial and Engineering Chemistry Research},
volume = {45},
number = {21},
pages = {7313--7320},
publisher = {American Chemical Society},
abstract = {In the present study, the gasification with air of dried sewage sludge (DSS) was experimentally investigated using a bubbling fluidized bed reactor. The experimental work analyzed the effect on the DSS gasification tests of the gas residence time (as a function of both the bed height and the superficial air velocity) and the potential catalytic role of the DSS ashes. Furthermore, the influence of the nonstationary period on the accumulated tar production was analyzed. The results show that a longer gas residence time improves the gas efficiency process. A decrease in tar production and an increase in H 2 content in the raw gas were observed when a mixture of sand and DSS ashes was used as an initial bed. These results confirm the catalytic effect of DSS ashes, which would be able for catalytic applications. The influence of the nonstationary period on the accumulated tar production was minimized when the experiment length was extended. This finding could confirm the higher tar production during this period. textcopyright 2006 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
In the present study, the gasification with air of dried sewage sludge (DSS) was experimentally investigated using a bubbling fluidized bed reactor. The experimental work analyzed the effect on the DSS gasification tests of the gas residence time (as a function of both the bed height and the superficial air velocity) and the potential catalytic role of the DSS ashes. Furthermore, the influence of the nonstationary period on the accumulated tar production was analyzed. The results show that a longer gas residence time improves the gas efficiency process. A decrease in tar production and an increase in H 2 content in the raw gas were observed when a mixture of sand and DSS ashes was used as an initial bed. These results confirm the catalytic effect of DSS ashes, which would be able for catalytic applications. The influence of the nonstationary period on the accumulated tar production was minimized when the experiment length was extended. This finding could confirm the higher tar production during this period. textcopyright 2006 American Chemical Society.
Manyà, Joan Josep; Sánchez, José Luis; Ábrego, Javier; Gonzalo, Alberto; Arauzo, Jesús
Influence of gas residence time and air ratio on the air gasification of dried sewage sludge in a bubbling fluidised bed Artículo de revista
En: Fuel, vol. 85, no 14-15, pp. 2027–2033, 2006, ISSN: 00162361.
@article{Manya2006b,
title = {Influence of gas residence time and air ratio on the air gasification of dried sewage sludge in a bubbling fluidised bed},
author = {Joan Josep Manyà and José Luis Sánchez and Javier Ábrego and Alberto Gonzalo and Jesús Arauzo},
doi = {10.1016/j.fuel.2006.04.008},
issn = {00162361},
year = {2006},
date = {2006-10-01},
journal = {Fuel},
volume = {85},
number = {14-15},
pages = {2027--2033},
publisher = {Elsevier},
abstract = {Because little information is available about sewage sludge gasification in a bubbling fluidised bed (BFB), further experiments are required to quantify the power generation potential of dried sewage sludge (DSS) as well as to evaluate the optimum conditions for its gasification. In this work, the influence of the bed height on the process was experimentally determined using a laboratory-scale BFB reactor. The gasification tests were performed at different values of equivalence ratio ($łambda$) and at two values of constant bed height (150 and 300 mm). Attention was focused on the effect of increasing bed height on the gas composition, average cold gas efficiency, and product distribution. Results obtained in this study show that a bed height increase improves the efficiency of the DSS gasification process. This fact could be explained because the high ash content of DSS represents an obstacle to the gas diffusion. textcopyright 2006 Elsevier Ltd. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Because little information is available about sewage sludge gasification in a bubbling fluidised bed (BFB), further experiments are required to quantify the power generation potential of dried sewage sludge (DSS) as well as to evaluate the optimum conditions for its gasification. In this work, the influence of the bed height on the process was experimentally determined using a laboratory-scale BFB reactor. The gasification tests were performed at different values of equivalence ratio ($łambda$) and at two values of constant bed height (150 and 300 mm). Attention was focused on the effect of increasing bed height on the gas composition, average cold gas efficiency, and product distribution. Results obtained in this study show that a bed height increase improves the efficiency of the DSS gasification process. This fact could be explained because the high ash content of DSS represents an obstacle to the gas diffusion. textcopyright 2006 Elsevier Ltd. All rights reserved.
Ayllón, María; Aznar, María; Sánchez, José Luis; Gea, Gloria; Arauzo, Jesús
Influence of temperature and heating rate on the fixed bed pyrolysis of meat and bone meal Artículo de revista
En: Chemical Engineering Journal, vol. 121, no 2-3, pp. 85–96, 2006, ISSN: 13858947.
@article{Ayllon2006,
title = {Influence of temperature and heating rate on the fixed bed pyrolysis of meat and bone meal},
author = {María Ayllón and María Aznar and José Luis Sánchez and Gloria Gea and Jesús Arauzo},
doi = {10.1016/j.cej.2006.04.013},
issn = {13858947},
year = {2006},
date = {2006-08-01},
journal = {Chemical Engineering Journal},
volume = {121},
number = {2-3},
pages = {85--96},
publisher = {Elsevier},
abstract = {This work is focused on the study of meat and bone meal pyrolysis in a fixed bed reactor, analysing the influence of the final pyrolysis temperature and heating rate on the product (char, tar and gas) distribution and composition and the char characterization. Two sets of experiments have been performed at different final pyrolysis temperatures between 300 and 900 °C and heating rates from 2 to 14 °C/min. From the results obtained it is observed that the effect of the final pyrolysis temperature is more important than the effect of the heating rate, except on the temperature profiles. The analysis of pyrolysis product distribution shows that the major products obtained were tar and char at any temperature or heating rate. Most of the decomposition takes place at temperatures lower than 500 °C, and no more significant decomposition is produced above 750 °C. The chars obtained present a low specific surface area, less than 45 m2/g. The tar obtained is mainly composed of more than 60% nitrogenated aliphatic compounds (such as nitriles, amides and cyclic compounds), 15% aliphatic hydrocarbons (such as alkanes and alkenes), 10% oxygenated aliphatic compounds (mostly carboxylic acids) and about 8% oxygenated aromatic compounds (mainly phenolics). textcopyright 2006 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
This work is focused on the study of meat and bone meal pyrolysis in a fixed bed reactor, analysing the influence of the final pyrolysis temperature and heating rate on the product (char, tar and gas) distribution and composition and the char characterization. Two sets of experiments have been performed at different final pyrolysis temperatures between 300 and 900 °C and heating rates from 2 to 14 °C/min. From the results obtained it is observed that the effect of the final pyrolysis temperature is more important than the effect of the heating rate, except on the temperature profiles. The analysis of pyrolysis product distribution shows that the major products obtained were tar and char at any temperature or heating rate. Most of the decomposition takes place at temperatures lower than 500 °C, and no more significant decomposition is produced above 750 °C. The chars obtained present a low specific surface area, less than 45 m2/g. The tar obtained is mainly composed of more than 60% nitrogenated aliphatic compounds (such as nitriles, amides and cyclic compounds), 15% aliphatic hydrocarbons (such as alkanes and alkenes), 10% oxygenated aliphatic compounds (mostly carboxylic acids) and about 8% oxygenated aromatic compounds (mainly phenolics). textcopyright 2006 Elsevier B.V. All rights reserved.
Mastral, José Francisco; Berrueco, César; Ceamanos, Jesús
Pyrolysis of high-density polyethylene in free-fall reactors in series Artículo de revista
En: Energy and Fuels, vol. 20, no 4, pp. 1365–1371, 2006, ISSN: 08870624.
@article{Mastral2006b,
title = {Pyrolysis of high-density polyethylene in free-fall reactors in series},
author = {José Francisco Mastral and César Berrueco and Jesús Ceamanos},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ef060007n},
issn = {08870624},
year = {2006},
date = {2006-07-01},
journal = {Energy and Fuels},
volume = {20},
number = {4},
pages = {1365--1371},
publisher = {American Chemical Society},
abstract = {Polyethylene pyrolysis has been studied analyzing the influence of temperature and residence time on the product distribution. The study was performed in an installation comprising two free-fall reactors in series, enabling the influence for both primary and secondary reactions to be studied separately. This also allows for the temperature to be increased in the second reaction zone, which is a parameter of great influence in the formation of aromatics. The use of reactors of different volume in the second zone also allows for the study of a broader range of residence times. The results obtained in the present work show qualitative trends similar to those obtained in other works of polyethylene pyrolysis in fluidized bed. At low temperatures, the main products obtained are solid waxes, while almost no aromatic compounds appear. The cracking rate increases with the rise in temperature, favoring the reaction of the heaviest fractions. Nevertheless, there are some differences. In general, ethylene, the direct product of the $beta$-scission of hydrocarbon chains, is the main compound in the gaseous fraction. The yields to methane and hydrogen increase as the temperature rises, with these being the final products of the degradation process and in the formation of aromatics. The production of aromatics and polycyclic aromatic hydrocarbons increases with the temperature and residence time. textcopyright 2006 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Polyethylene pyrolysis has been studied analyzing the influence of temperature and residence time on the product distribution. The study was performed in an installation comprising two free-fall reactors in series, enabling the influence for both primary and secondary reactions to be studied separately. This also allows for the temperature to be increased in the second reaction zone, which is a parameter of great influence in the formation of aromatics. The use of reactors of different volume in the second zone also allows for the study of a broader range of residence times. The results obtained in the present work show qualitative trends similar to those obtained in other works of polyethylene pyrolysis in fluidized bed. At low temperatures, the main products obtained are solid waxes, while almost no aromatic compounds appear. The cracking rate increases with the rise in temperature, favoring the reaction of the heaviest fractions. Nevertheless, there are some differences. In general, ethylene, the direct product of the $beta$-scission of hydrocarbon chains, is the main compound in the gaseous fraction. The yields to methane and hydrogen increase as the temperature rises, with these being the final products of the degradation process and in the formation of aromatics. The production of aromatics and polycyclic aromatic hydrocarbons increases with the temperature and residence time. textcopyright 2006 American Chemical Society.
2005
Artículos de revista
Sánchez, José Luis; Gonzalo, Alberto; Gea, Gloria; Bilbao, Rafael; Arauzo, Jesús
Straw black liquor steam reforming in a fluidized bed reactor. Effect of temperature and bed substitution at pilot scale Artículo de revista
En: Energy and Fuels, vol. 19, no 5, pp. 2140–2147, 2005, ISSN: 08870624.
@article{Sanchez2005,
title = {Straw black liquor steam reforming in a fluidized bed reactor. Effect of temperature and bed substitution at pilot scale},
author = {José Luis Sánchez and Alberto Gonzalo and Gloria Gea and Rafael Bilbao and Jesús Arauzo},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ef050020s},
issn = {08870624},
year = {2005},
date = {2005-09-01},
journal = {Energy and Fuels},
volume = {19},
number = {5},
pages = {2140--2147},
publisher = {American Chemical Society},
abstract = {Gasification via the steam reforming of straw black liquor (BL) was performed in a pilot-plant fluidized bed reactor. The effects of bed material replacement (from an initial bed of calcium carbonate to a bed composed of BL char) and bed temperature (575-640 °C) on the dry gas composition, the dry gas lower heating value (LHV), gas yield, fraction of carbon to gas, and cold gas efficiency have been investigated. Although bed defluidization problems were experienced under the operating conditions tested, a medium heating value gas (with a dry gas LHV of ∼8200 kJ/m3 STP) (where STP indicates standard temperature and pressure) was obtained, composed mainly of H2 (65 vol %) and CO2 (30 vol %). Because of the high ratio of steam to biomass used, little influence of the reaction temperature on the gas composition was observed at >550 °C. At 600 °C, which is a temperature lower than that usually utilized in biomass gasification, ∼2.2 m3 STP/kg daf of gas production, 75% carbon conversion to gas, and a cold gas efficiency of 90% were achieved, showing that the low-temperature steam reforming of BL could be a suitable process if bed defluidization can be overcome. textcopyright 2005 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Gasification via the steam reforming of straw black liquor (BL) was performed in a pilot-plant fluidized bed reactor. The effects of bed material replacement (from an initial bed of calcium carbonate to a bed composed of BL char) and bed temperature (575-640 °C) on the dry gas composition, the dry gas lower heating value (LHV), gas yield, fraction of carbon to gas, and cold gas efficiency have been investigated. Although bed defluidization problems were experienced under the operating conditions tested, a medium heating value gas (with a dry gas LHV of ∼8200 kJ/m3 STP) (where STP indicates standard temperature and pressure) was obtained, composed mainly of H2 (65 vol %) and CO2 (30 vol %). Because of the high ratio of steam to biomass used, little influence of the reaction temperature on the gas composition was observed at >550 °C. At 600 °C, which is a temperature lower than that usually utilized in biomass gasification, ∼2.2 m3 STP/kg daf of gas production, 75% carbon conversion to gas, and a cold gas efficiency of 90% were achieved, showing that the low-temperature steam reforming of BL could be a suitable process if bed defluidization can be overcome. textcopyright 2005 American Chemical Society.
Gea, Gloria; Sánchez, José Luis; Murillo, María Benita; Arauzo, Jesús
En: Industrial and Engineering Chemistry Research, vol. 44, no 17, pp. 6583–6590, 2005, ISSN: 08885885.
@article{Gea2005,
title = {Kinetics of CO2 gasification of alkaline black liquor from wheat straw. 2. Evolution of CO2 reactivity with the solid conversion and influence of temperature on the gasification rate},
author = {Gloria Gea and José Luis Sánchez and María Benita Murillo and Jesús Arauzo},
doi = {10.1021/ie048772h},
issn = {08885885},
year = {2005},
date = {2005-08-01},
journal = {Industrial and Engineering Chemistry Research},
volume = {44},
number = {17},
pages = {6583--6590},
abstract = {Results obtained in recent studies have shown that black liquor (BL) gasification can be considered as an attractive recovery system. However, limited information has been published on the gasification kinetics of alkaline BL char (ABLC). Part 1 of this work (Gea, G.; Sánchez, J. L.; Murillo, M. B.; Arauzo, J. Ind. Eng. Chem. Res. 2004, 43, 3233) studied the CO2 gasification of ABLC, specifically the influence of [CO] and [CC2] on the gasification rate at different temperatures. The present work is focused on the variation of this reaction rate with solid conversion during the gasification process. The results obtained show that the gasification rate increases with the solid conversion up to a maximum value and then decreases. The effect of various factors such as pyrolysis operating conditions on this variation has also been analyzed. Furthermore, the dependence of the ABLC gasification rate on the temperature has been evaluated, and the apparent average activation energy over the range 170-234 kJ/mol has been determined for the temperature range 750-850 °C. textcopyright 2005 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Results obtained in recent studies have shown that black liquor (BL) gasification can be considered as an attractive recovery system. However, limited information has been published on the gasification kinetics of alkaline BL char (ABLC). Part 1 of this work (Gea, G.; Sánchez, J. L.; Murillo, M. B.; Arauzo, J. Ind. Eng. Chem. Res. 2004, 43, 3233) studied the CO2 gasification of ABLC, specifically the influence of [CO] and [CC2] on the gasification rate at different temperatures. The present work is focused on the variation of this reaction rate with solid conversion during the gasification process. The results obtained show that the gasification rate increases with the solid conversion up to a maximum value and then decreases. The effect of various factors such as pyrolysis operating conditions on this variation has also been analyzed. Furthermore, the dependence of the ABLC gasification rate on the temperature has been evaluated, and the apparent average activation energy over the range 170-234 kJ/mol has been determined for the temperature range 750-850 °C. textcopyright 2005 American Chemical Society.
Galdámez, J Román; García, Lucía; Bilbao, Rafael
Hydrogen production by steam reforming of bio-oil using coprecipitated Ni-Al catalysts. Acetic acid as a model compound Artículo de revista
En: Energy and Fuels, vol. 19, no 3, pp. 1133–1142, 2005, ISSN: 08870624.
@article{RomanGaldamez2005,
title = {Hydrogen production by steam reforming of bio-oil using coprecipitated Ni-Al catalysts. Acetic acid as a model compound},
author = {J Román Galdámez and Lucía García and Rafael Bilbao},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ef049718g},
issn = {08870624},
year = {2005},
date = {2005-05-01},
journal = {Energy and Fuels},
volume = {19},
number = {3},
pages = {1133--1142},
publisher = {American Chemical Society},
abstract = {Catalytic steam reforming of bio-oil is a promising process for hydrogen production from biomass. Bio-oil is a complex mixture of a large number of compounds (acids, aldehydes, alcohols, and ketones, among other compounds), and acetic acid has been selected as a model compound. The experimental work has been conducted in a fluidized-bed reactor. Noncatalytic steam reforming of acetic acid has been performed from 450 °C to 700 °C. For catalytic experiments, coprecipitated Ni-Al catalysts, some promoted with lanthanum, have been selected, because of their high mechanical strength and suitable performance in biomass steam gasification. The presence of the catalyst, its reduction, promotion with lanthanum, and the influence of space velocity on gas yields have been analyzed at 650 °C. Catalytic experiments show a significant increase in total gas, H2, and CO2 yields, whereas CH4 and C2 yields decrease, when compared with those from noncatalytic experiments. Gas yields obtained in the catalytic process present a shift from the noncatalytic process to equilibrium gas yields. Promotion with lanthanum does not increase the H2 yield achieved with the Ni-Al catalyst. Simple first-order kinetic equations have been proposed for the formation of H2 and CO2 and the disappearance of CH4 and C2. textcopyright 2005 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Catalytic steam reforming of bio-oil is a promising process for hydrogen production from biomass. Bio-oil is a complex mixture of a large number of compounds (acids, aldehydes, alcohols, and ketones, among other compounds), and acetic acid has been selected as a model compound. The experimental work has been conducted in a fluidized-bed reactor. Noncatalytic steam reforming of acetic acid has been performed from 450 °C to 700 °C. For catalytic experiments, coprecipitated Ni-Al catalysts, some promoted with lanthanum, have been selected, because of their high mechanical strength and suitable performance in biomass steam gasification. The presence of the catalyst, its reduction, promotion with lanthanum, and the influence of space velocity on gas yields have been analyzed at 650 °C. Catalytic experiments show a significant increase in total gas, H2, and CO2 yields, whereas CH4 and C2 yields decrease, when compared with those from noncatalytic experiments. Gas yields obtained in the catalytic process present a shift from the noncatalytic process to equilibrium gas yields. Promotion with lanthanum does not increase the H2 yield achieved with the Ni-Al catalyst. Simple first-order kinetic equations have been proposed for the formation of H2 and CO2 and the disappearance of CH4 and C2. textcopyright 2005 American Chemical Society.
Liesa, Fernando; Alzueta, María U; Millera, Ángela; Bilbao, Rafael
An experimental and computational fluid dynamics (CFD) simulation study of reburning under laboratory turbulent mixing conditions Artículo de revista
En: Energy and Fuels, vol. 19, no 3, pp. 833–841, 2005, ISSN: 08870624.
@article{Liesa2005,
title = {An experimental and computational fluid dynamics (CFD) simulation study of reburning under laboratory turbulent mixing conditions},
author = {Fernando Liesa and María U Alzueta and Ángela Millera and Rafael Bilbao},
doi = {10.1021/ef049757s},
issn = {08870624},
year = {2005},
date = {2005-05-01},
journal = {Energy and Fuels},
volume = {19},
number = {3},
pages = {833--841},
abstract = {A combined experimental and computational fluid dynamics CFD modeling study of the reburn process under turbulent mixing conditions on a laboratory scale has been performed. The experimental work includes novel laboratory results of reburn under different mixing conditions, and intends to cover the gap between the studies of the reburn process made in ideal reactors and the studies conducted in pilot-scale and full-scale plants that are available in the literature. A model has been developed using the AIOLOS software, together with a reduced description of the chemistry taken from literature, and it allows us to describe the reburn process, reproducing the main features that occur in the experimental system, and thus it can be used as a useful tool for prediction and optimization of the NO reduction by reburn. The results obtained indicate the necessity for considering a detailed description of mixing, because they indicate that simple modeling approaches, such as the plug flow reactor and the Zwietering configuration descriptions, fail to describe, in detail, what occurs experimentally in well-controlled laboratory experiments in which turbulent mixing occurs. In addition, the main effect of mixing between the reburn fuel and the primary combustion gases has been determined to be the modification of the local stoichiometry, which is ultimately responsible for the variation of the NO reduction. A significant synergy between the variables that are influencing the reburn process and the mixing conditions is observed, and this indicates the necessity of not neglecting any of the variables for the assessment of the NO reduction and for optimization of the reduction process. textcopyright 2005 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A combined experimental and computational fluid dynamics CFD modeling study of the reburn process under turbulent mixing conditions on a laboratory scale has been performed. The experimental work includes novel laboratory results of reburn under different mixing conditions, and intends to cover the gap between the studies of the reburn process made in ideal reactors and the studies conducted in pilot-scale and full-scale plants that are available in the literature. A model has been developed using the AIOLOS software, together with a reduced description of the chemistry taken from literature, and it allows us to describe the reburn process, reproducing the main features that occur in the experimental system, and thus it can be used as a useful tool for prediction and optimization of the NO reduction by reburn. The results obtained indicate the necessity for considering a detailed description of mixing, because they indicate that simple modeling approaches, such as the plug flow reactor and the Zwietering configuration descriptions, fail to describe, in detail, what occurs experimentally in well-controlled laboratory experiments in which turbulent mixing occurs. In addition, the main effect of mixing between the reburn fuel and the primary combustion gases has been determined to be the modification of the local stoichiometry, which is ultimately responsible for the variation of the NO reduction. A significant synergy between the variables that are influencing the reburn process and the mixing conditions is observed, and this indicates the necessity of not neglecting any of the variables for the assessment of the NO reduction and for optimization of the reduction process. textcopyright 2005 American Chemical Society.
Manyà, Joan Josep; Sánchez, José Luis; Gonzalo, Alberto; Arauzo, Jesús
Air gasification of dried sewage sludge in a fluidized bed: Effect of the operating conditions and in-bed use of alumina Artículo de revista
En: Energy and Fuels, vol. 19, no 2, pp. 629–636, 2005, ISSN: 08870624.
@article{Manya2005,
title = {Air gasification of dried sewage sludge in a fluidized bed: Effect of the operating conditions and in-bed use of alumina},
author = {Joan Josep Manyà and José Luis Sánchez and Alberto Gonzalo and Jesús Arauzo},
url = {https://pubs.acs.org/sharingguidelines},
doi = {10.1021/ef0497614},
issn = {08870624},
year = {2005},
date = {2005-03-01},
journal = {Energy and Fuels},
volume = {19},
number = {2},
pages = {629--636},
publisher = {American Chemical Society},
abstract = {Sewage sludge has recently become a particularly important problem all over the world because of its harmful impact on the environment. The consequent need to develop alternative processes for the use of dried sewage sludge for energy purposes, such as gasification, requires experimental tests in order to quantify the potential energy power of the sludge, as well as to evaluate the optimum conditions for its gasification. There is, however, little information available. In this study, the gasification with air of dried sewage sludge was experimentally investigated using a bubbling fluidized bed. Attention was focused on the influence of the temperature (750-850 °C), the equivalence ratio (25-35%), and the fluidizing velocity (5, 8, and 11 times the value of Umf) on the product yields, gas composition, thermal efficiency, and tar content. The results obtained show the potential for using sewage sludge gasification with air as an option for energy recovery and waste treatment. However, the high tar yield obtained needs to be reduced. Consequently, experiments involving the in-bed use of alumina were carried out. This primary measure has proven effective for tar removal (the content decreases by nearly 40% with in-bed use of alumina at 5 wt%). textcopyright 2005 American Chemical Society.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Sewage sludge has recently become a particularly important problem all over the world because of its harmful impact on the environment. The consequent need to develop alternative processes for the use of dried sewage sludge for energy purposes, such as gasification, requires experimental tests in order to quantify the potential energy power of the sludge, as well as to evaluate the optimum conditions for its gasification. There is, however, little information available. In this study, the gasification with air of dried sewage sludge was experimentally investigated using a bubbling fluidized bed. Attention was focused on the influence of the temperature (750-850 °C), the equivalence ratio (25-35%), and the fluidizing velocity (5, 8, and 11 times the value of Umf) on the product yields, gas composition, thermal efficiency, and tar content. The results obtained show the potential for using sewage sludge gasification with air as an option for energy recovery and waste treatment. However, the high tar yield obtained needs to be reduced. Consequently, experiments involving the in-bed use of alumina were carried out. This primary measure has proven effective for tar removal (the content decreases by nearly 40% with in-bed use of alumina at 5 wt%). textcopyright 2005 American Chemical Society.
Proceedings Articles
Guerrero, Marta; Ruiz, Pilar M; Alzueta, María U; Bilbao, Rafael; Millera, Ángela
Pyrolysis of eucalyptus at different heating rates: Studies of char characterization and oxidative reactivity Proceedings Article
En: Journal of Analytical and Applied Pyrolysis, pp. 307–314, Elsevier, 2005, ISSN: 01652370.
@inproceedings{Guerrero2005,
title = {Pyrolysis of eucalyptus at different heating rates: Studies of char characterization and oxidative reactivity},
author = {Marta Guerrero and Pilar M Ruiz and María U Alzueta and Rafael Bilbao and Ángela Millera},
doi = {10.1016/j.jaap.2004.12.008},
issn = {01652370},
year = {2005},
date = {2005-08-01},
booktitle = {Journal of Analytical and Applied Pyrolysis},
volume = {74},
number = {1-2},
pages = {307--314},
publisher = {Elsevier},
abstract = {Biomass is increasingly considered as an important resource for alternative fuels with significant environmental advantages. Recent studies in the literature highlight the importance of the structural modifications which occur after biomass devolatilization is performed under different conditions and their effect on char reactivity. In this context, this work deals with the characterization of chars obtained by the pyrolysis of eucalyptus at different temperatures and heating rates and the influence of their morphological changes on overall reactivity towards oxygen. Pyrolysis experiments at low heating rate (LHR) were carried out in a fixed bed reactor, in the range of 600-900 °C, while a fluidized bed reactor was employed for preparing chars at high heating rate (HHR), at 800 and 900 °C. Results relating to the elemental chemical composition of the chars are reported. In addition, pore volume and surface area of char particles were determined by CO2 adsorption at 0 °C using the Dubinin-Radushkevich method. Chars were also observed by scanning electron microscopy (SEM) in order to visualize the differences in macro-morphology. LHR and HHR chars obtained at 900 °C were selected in order to investigate their oxidation behaviour and these results are discussed in terms of ultimate, surface area and SEM analyses. textcopyright 2005 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Biomass is increasingly considered as an important resource for alternative fuels with significant environmental advantages. Recent studies in the literature highlight the importance of the structural modifications which occur after biomass devolatilization is performed under different conditions and their effect on char reactivity. In this context, this work deals with the characterization of chars obtained by the pyrolysis of eucalyptus at different temperatures and heating rates and the influence of their morphological changes on overall reactivity towards oxygen. Pyrolysis experiments at low heating rate (LHR) were carried out in a fixed bed reactor, in the range of 600-900 °C, while a fluidized bed reactor was employed for preparing chars at high heating rate (HHR), at 800 and 900 °C. Results relating to the elemental chemical composition of the chars are reported. In addition, pore volume and surface area of char particles were determined by CO2 adsorption at 0 °C using the Dubinin-Radushkevich method. Chars were also observed by scanning electron microscopy (SEM) in order to visualize the differences in macro-morphology. LHR and HHR chars obtained at 900 °C were selected in order to investigate their oxidation behaviour and these results are discussed in terms of ultimate, surface area and SEM analyses. textcopyright 2005 Elsevier B.V. All rights reserved.
Berrueco, César; Esperanza, Ernesto; Mastral, José Francisco; Ceamanos, Jesús; García-Bacaicoa, Pedro
Pyrolysis of waste tyres in an atmospheric static-bed batch reactor: Analysis of the gases obtained Proceedings Article
En: Journal of Analytical and Applied Pyrolysis, pp. 245–253, Elsevier, 2005, ISSN: 01652370.
@inproceedings{Berrueco2005,
title = {Pyrolysis of waste tyres in an atmospheric static-bed batch reactor: Analysis of the gases obtained},
author = {César Berrueco and Ernesto Esperanza and José Francisco Mastral and Jesús Ceamanos and Pedro García-Bacaicoa},
doi = {10.1016/j.jaap.2004.10.007},
issn = {01652370},
year = {2005},
date = {2005-08-01},
booktitle = {Journal of Analytical and Applied Pyrolysis},
volume = {74},
number = {1-2},
pages = {245--253},
publisher = {Elsevier},
abstract = {Scrap tyre pyrolysis was studied under nitrogen atmospheric pressure in order to analyse temperature influence on the global yields and the gas composition. A static-bed batch reactor was used to pyrolyse 300 g of shredded scrap tyres at temperatures from 400 to 700 °C. The reactor was externally heated by means of electrical resistances, the heating rate being approximately 12 K min-1. Once the required system temperature was reached and stabilised, it was maintained for 4 h. The residence time of the gas in the reactor was calculated, with values falling between 1 and 1.5 min. Three phases were obtained after pyrolysis: solid (char), liquid (water and oils) and gas (light hydrocarbons, H2, CO and CO2). The product distribution and composition were studied as a function of the thermal treatment. Global yields were determined as follows: char, 47-63 wt.%, oils, 30-43 wt.%, and gas, 2.4-4.4 wt.%. It was observed that the liquid yield increases with temperature from 400 to 500 °C. However, from 500 °C on, this parameter remained almost constant. The solid yield followed an inverse trend to that observed for the liquid yield. On the other hand, the gas yield showed a slight continuous growth with temperatures ranging from 400 °C (2.4 wt.%) to 700 °C (4.4 wt.%). The gas phase was analysed off-line by gas chromatography. The main gases produced from the pyrolysis process were H 2, CO, CO2 and hydrocarbons: CH4, C 2H4, C3H6 and C4H 8. It was observed that the fraction of light gases (H2, CO, CO2 and CH4) was greater at higher temperatures. textcopyright 2004 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
Scrap tyre pyrolysis was studied under nitrogen atmospheric pressure in order to analyse temperature influence on the global yields and the gas composition. A static-bed batch reactor was used to pyrolyse 300 g of shredded scrap tyres at temperatures from 400 to 700 °C. The reactor was externally heated by means of electrical resistances, the heating rate being approximately 12 K min-1. Once the required system temperature was reached and stabilised, it was maintained for 4 h. The residence time of the gas in the reactor was calculated, with values falling between 1 and 1.5 min. Three phases were obtained after pyrolysis: solid (char), liquid (water and oils) and gas (light hydrocarbons, H2, CO and CO2). The product distribution and composition were studied as a function of the thermal treatment. Global yields were determined as follows: char, 47-63 wt.%, oils, 30-43 wt.%, and gas, 2.4-4.4 wt.%. It was observed that the liquid yield increases with temperature from 400 to 500 °C. However, from 500 °C on, this parameter remained almost constant. The solid yield followed an inverse trend to that observed for the liquid yield. On the other hand, the gas yield showed a slight continuous growth with temperatures ranging from 400 °C (2.4 wt.%) to 700 °C (4.4 wt.%). The gas phase was analysed off-line by gas chromatography. The main gases produced from the pyrolysis process were H 2, CO, CO2 and hydrocarbons: CH4, C 2H4, C3H6 and C4H 8. It was observed that the fraction of light gases (H2, CO, CO2 and CH4) was greater at higher temperatures. textcopyright 2004 Elsevier B.V. All rights reserved.
Mendiara, Teresa; Domene, M P; Millera, Ángela; Bilbao, Rafael; Alzueta, María U
An experimental study of the soot formed in the pyrolysis of acetylene Proceedings Article
En: Journal of Analytical and Applied Pyrolysis, pp. 486–493, Elsevier, 2005, ISSN: 01652370.
@inproceedings{Mendiara2005,
title = {An experimental study of the soot formed in the pyrolysis of acetylene},
author = {Teresa Mendiara and M P Domene and Ángela Millera and Rafael Bilbao and María U Alzueta},
doi = {10.1016/j.jaap.2004.11.019},
issn = {01652370},
year = {2005},
date = {2005-08-01},
booktitle = {Journal of Analytical and Applied Pyrolysis},
volume = {74},
number = {1-2},
pages = {486--493},
publisher = {Elsevier},
abstract = {A study of the formation of soot from the pyrolysis of acetylene has been performed in laboratory scale using a quartz reactor heated by an electric oven. The work includes a systematic parametric study in which we have varied: temperature (800, 900, 1000 and 1100 °C), initial hydrocarbon concentration (1, 5 and 10% of acetylene), space time (8.1 and 16.2 s), presence and oxygen concentration (0 and 1000 ppm), and presence and level of water (0, 3 and 15%). In those experiments, we quantified the soot formed, which was further characterized through ultimate analysis, determination of BET area and SEM techniques, and we also determined the outlet concentrations of CO, CO 2 and different gaseous hydrocarbon species (C2H 2, CH4, C2H6, C2H 4 and C6H6). The results show that increasing the reaction temperature and the initial concentration of C2H 2, as well as the space time, results in favouring the formation of soot. The amount of soot formed exhibits a maximum in presence of oxygen and water in the reactant mixture. textcopyright 2004 Elsevier B.V. All rights reserved.},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
A study of the formation of soot from the pyrolysis of acetylene has been performed in laboratory scale using a quartz reactor heated by an electric oven. The work includes a systematic parametric study in which we have varied: temperature (800, 900, 1000 and 1100 °C), initial hydrocarbon concentration (1, 5 and 10% of acetylene), space time (8.1 and 16.2 s), presence and oxygen concentration (0 and 1000 ppm), and presence and level of water (0, 3 and 15%). In those experiments, we quantified the soot formed, which was further characterized through ultimate analysis, determination of BET area and SEM techniques, and we also determined the outlet concentrations of CO, CO 2 and different gaseous hydrocarbon species (C2H 2, CH4, C2H6, C2H 4 and C6H6). The results show that increasing the reaction temperature and the initial concentration of C2H 2, as well as the space time, results in favouring the formation of soot. The amount of soot formed exhibits a maximum in presence of oxygen and water in the reactant mixture. textcopyright 2004 Elsevier B.V. All rights reserved.