The Experts below are selected from a list of 16101 Experts worldwide ranked by ideXlab platform
M Menendez - One of the best experts on this subject based on the ideXlab platform.
-
pure hydrogen from biogas intensified methane dry reforming in a two zone Fluidized Bed Reactor using permselective membranes
Chemical Engineering Journal, 2019Co-Authors: P. Duran, A Sanzmartinez, J Soler, M Menendez, Javier HerguidoAbstract:Abstract Methane dry reforming of biogas can be a sustainable source of hydrogen but the development of this technology is hindered by limitations such as endothermicity and catalyst deactivation by coke. A two zone Fluidized Bed Reactor coupling permselective Pd/Ag membranes counteracts them and allows to intensify the process obtaining a stable pure hydrogen production. Here we report the effect of operation variables (i.e., temperature, total Bed height, nature and partial pressure of regenerative agent, relative height of the regeneration and reaction zones, and use of an activation period) on the yield to hydrogen and stability of the process. Hydrogen over-yields, compared with the conventional Fluidized Bed Reactor, in the range of +200% to +100% were obtained for the entire interval of temperatures 475–575 °C whilst maintaining stable operation by continuous catalyst regeneration. Around 70% of it was pure hydrogen coming from the permeate side of the membranes. The proposed Reactor configuration greatly increases both methane conversion and selectivity to hydrogen (expressed as H2/CO ratio), not only in relation to our own conventional Reactor findings but also regarding other published results.
-
glycerol steam reforming with low steam glycerol ratio in a two zone Fluidized Bed Reactor
Catalysis Today, 2018Co-Authors: Miriam Yus, Javier Herguido, J Soler, M MenendezAbstract:Abstract The production of hydrogen from glycerol steam reforming has been studied in several Reactors. In conventional Reactors the catalyst is deactivated by coke: in fixed Bed Reactors plugging was observed if a low steam/glycerol ratio was employed, while in Fluidized Bed Reactors it was possible to operate for a longer time-on-stream. The use of a two-zone Fluidized Bed Reactor is studied in this work, as a method to counteract the problem of catalyst deactivation by coke. The glycerol reforming takes place in the upper part of this Reactor while the catalyst is simultaneously regenerated in the lower part, where a stream of a regenerating gas is introduced. It has been found that CO 2 , O 2 or H 2 O can act as regenerating gas in a two-zone-Fluidized Bed Reactor, allowing steady state operation at a water:glycerol molar ratio as low as 1.25. The effect of the operating conditions has been studied and the yield to the main products was compared with the calculated values assuming thermodynamic equilibrium.
-
stable hydrogen production by methane steam reforming in a two zone Fluidized Bed Reactor experimental assessment
Journal of Power Sources, 2013Co-Authors: L Perezmoreno, Javier Herguido, J Soler, M MenendezAbstract:Abstract The Two Zone Fluidized Bed Reactor concept is proposed for hydrogen production via the steam reforming of methane (SRM) including integrated catalyst regeneration. In order to study the effect of the contact mode, the oxidative SRM has been carried out over a Ni/Al 2 O 3 catalyst using a fixed Bed Reactor (fBR), a conventional Fluidized-Bed Reactor (FBR) and the proposed two-zone Fluidized Bed Reactor (TZFBR). The technical feasibility of these Reactors has been studied experimentally, investigating their performance (CH 4 conversion, CO and H 2 selectivity, and H 2 global yield) and stability under different operating conditions. Coke generation in the process has been verified by several techniques. A stable performance was obtained in the TZFBR, where coke formation was counteracted with continuous catalyst regeneration. The viability of the TZFBR for carrying out this process with a valuable global yield to hydrogen is demonstrated.
-
particle mixing in a two section two zone Fluidized Bed Reactor experimental technique and counter current back mixing model validation
Industrial & Engineering Chemistry Research, 2013Co-Authors: Ignacio Julián, Javier Herguido, M MenendezAbstract:Effective particle circulation between the two zones is a prerequisite for ensuring the simultaneous reaction and catalyst regeneration inside a two-zone Fluidized Bed Reactor (TZFBR). An appropria...
-
stable hydrogen production by methane steam reforming in a two zone Fluidized Bed Reactor effect of the operating variables
International Journal of Hydrogen Energy, 2013Co-Authors: L Perezmoreno, Javier Herguido, J Soler, M MenendezAbstract:Abstract The oxidative steam reforming of methane in a two-zone Fluidized-Bed Reactor (TZFBR) was investigated over a Ni/Al 2 O 3 catalyst. The effects of the main operating variables (temperature, steam/oxygen ratio, steam/methane ratio and relative velocity with respect to the minimum fluidization velocity) have been studied. A comparison has been made with results given in the literature in terms of hydrogen yield. Despite working with very low steam/methane ratios, high values of hydrogen yield at both high methane conversion and at steady state were obtained in the TZFBR.
Javier Herguido - One of the best experts on this subject based on the ideXlab platform.
-
pure hydrogen from biogas intensified methane dry reforming in a two zone Fluidized Bed Reactor using permselective membranes
Chemical Engineering Journal, 2019Co-Authors: P. Duran, A Sanzmartinez, J Soler, M Menendez, Javier HerguidoAbstract:Abstract Methane dry reforming of biogas can be a sustainable source of hydrogen but the development of this technology is hindered by limitations such as endothermicity and catalyst deactivation by coke. A two zone Fluidized Bed Reactor coupling permselective Pd/Ag membranes counteracts them and allows to intensify the process obtaining a stable pure hydrogen production. Here we report the effect of operation variables (i.e., temperature, total Bed height, nature and partial pressure of regenerative agent, relative height of the regeneration and reaction zones, and use of an activation period) on the yield to hydrogen and stability of the process. Hydrogen over-yields, compared with the conventional Fluidized Bed Reactor, in the range of +200% to +100% were obtained for the entire interval of temperatures 475–575 °C whilst maintaining stable operation by continuous catalyst regeneration. Around 70% of it was pure hydrogen coming from the permeate side of the membranes. The proposed Reactor configuration greatly increases both methane conversion and selectivity to hydrogen (expressed as H2/CO ratio), not only in relation to our own conventional Reactor findings but also regarding other published results.
-
Table_1_Methane Aromatization in a Fluidized Bed Reactor: Parametric Study.DOCX
2019Co-Authors: Javier Lasobras, Javier Herguido, Miguel Menéndez, Jaime Soler, Alonso Jimenez, Mariana Da Silva, María J. Franco, Izaskun Barrio, Jesús LàzaroAbstract:Methane aromatization is a promising technology for the transformation of natural gas into liquid products, but suffers from the problem of catalyst deactivation by coke. A two-zone Fluidized Bed Reactor has been proposed as a tool to counteract the catalyst deactivation, by providing continuous catalyst regeneration in the same vessel where the main reaction is carried out. This work shows the effect of the main operating conditions (carburization temperature, reaction temperature, carburization time, nature of regenerating agent and feed flow and height of the hydrocarbon entry point). Optimal reduction time and temperature were 1 h and 350°C. Best conversion and selectivity were achieved at 700°C without catalyst deactivation in the TZFBR.
-
glycerol steam reforming with low steam glycerol ratio in a two zone Fluidized Bed Reactor
Catalysis Today, 2018Co-Authors: Miriam Yus, Javier Herguido, J Soler, M MenendezAbstract:Abstract The production of hydrogen from glycerol steam reforming has been studied in several Reactors. In conventional Reactors the catalyst is deactivated by coke: in fixed Bed Reactors plugging was observed if a low steam/glycerol ratio was employed, while in Fluidized Bed Reactors it was possible to operate for a longer time-on-stream. The use of a two-zone Fluidized Bed Reactor is studied in this work, as a method to counteract the problem of catalyst deactivation by coke. The glycerol reforming takes place in the upper part of this Reactor while the catalyst is simultaneously regenerated in the lower part, where a stream of a regenerating gas is introduced. It has been found that CO 2 , O 2 or H 2 O can act as regenerating gas in a two-zone-Fluidized Bed Reactor, allowing steady state operation at a water:glycerol molar ratio as low as 1.25. The effect of the operating conditions has been studied and the yield to the main products was compared with the calculated values assuming thermodynamic equilibrium.
-
stable hydrogen production by methane steam reforming in a two zone Fluidized Bed Reactor experimental assessment
Journal of Power Sources, 2013Co-Authors: L Perezmoreno, Javier Herguido, J Soler, M MenendezAbstract:Abstract The Two Zone Fluidized Bed Reactor concept is proposed for hydrogen production via the steam reforming of methane (SRM) including integrated catalyst regeneration. In order to study the effect of the contact mode, the oxidative SRM has been carried out over a Ni/Al 2 O 3 catalyst using a fixed Bed Reactor (fBR), a conventional Fluidized-Bed Reactor (FBR) and the proposed two-zone Fluidized Bed Reactor (TZFBR). The technical feasibility of these Reactors has been studied experimentally, investigating their performance (CH 4 conversion, CO and H 2 selectivity, and H 2 global yield) and stability under different operating conditions. Coke generation in the process has been verified by several techniques. A stable performance was obtained in the TZFBR, where coke formation was counteracted with continuous catalyst regeneration. The viability of the TZFBR for carrying out this process with a valuable global yield to hydrogen is demonstrated.
-
particle mixing in a two section two zone Fluidized Bed Reactor experimental technique and counter current back mixing model validation
Industrial & Engineering Chemistry Research, 2013Co-Authors: Ignacio Julián, Javier Herguido, M MenendezAbstract:Effective particle circulation between the two zones is a prerequisite for ensuring the simultaneous reaction and catalyst regeneration inside a two-zone Fluidized Bed Reactor (TZFBR). An appropria...
J Soler - One of the best experts on this subject based on the ideXlab platform.
-
pure hydrogen from biogas intensified methane dry reforming in a two zone Fluidized Bed Reactor using permselective membranes
Chemical Engineering Journal, 2019Co-Authors: P. Duran, A Sanzmartinez, J Soler, M Menendez, Javier HerguidoAbstract:Abstract Methane dry reforming of biogas can be a sustainable source of hydrogen but the development of this technology is hindered by limitations such as endothermicity and catalyst deactivation by coke. A two zone Fluidized Bed Reactor coupling permselective Pd/Ag membranes counteracts them and allows to intensify the process obtaining a stable pure hydrogen production. Here we report the effect of operation variables (i.e., temperature, total Bed height, nature and partial pressure of regenerative agent, relative height of the regeneration and reaction zones, and use of an activation period) on the yield to hydrogen and stability of the process. Hydrogen over-yields, compared with the conventional Fluidized Bed Reactor, in the range of +200% to +100% were obtained for the entire interval of temperatures 475–575 °C whilst maintaining stable operation by continuous catalyst regeneration. Around 70% of it was pure hydrogen coming from the permeate side of the membranes. The proposed Reactor configuration greatly increases both methane conversion and selectivity to hydrogen (expressed as H2/CO ratio), not only in relation to our own conventional Reactor findings but also regarding other published results.
-
glycerol steam reforming with low steam glycerol ratio in a two zone Fluidized Bed Reactor
Catalysis Today, 2018Co-Authors: Miriam Yus, Javier Herguido, J Soler, M MenendezAbstract:Abstract The production of hydrogen from glycerol steam reforming has been studied in several Reactors. In conventional Reactors the catalyst is deactivated by coke: in fixed Bed Reactors plugging was observed if a low steam/glycerol ratio was employed, while in Fluidized Bed Reactors it was possible to operate for a longer time-on-stream. The use of a two-zone Fluidized Bed Reactor is studied in this work, as a method to counteract the problem of catalyst deactivation by coke. The glycerol reforming takes place in the upper part of this Reactor while the catalyst is simultaneously regenerated in the lower part, where a stream of a regenerating gas is introduced. It has been found that CO 2 , O 2 or H 2 O can act as regenerating gas in a two-zone-Fluidized Bed Reactor, allowing steady state operation at a water:glycerol molar ratio as low as 1.25. The effect of the operating conditions has been studied and the yield to the main products was compared with the calculated values assuming thermodynamic equilibrium.
-
stable hydrogen production by methane steam reforming in a two zone Fluidized Bed Reactor experimental assessment
Journal of Power Sources, 2013Co-Authors: L Perezmoreno, Javier Herguido, J Soler, M MenendezAbstract:Abstract The Two Zone Fluidized Bed Reactor concept is proposed for hydrogen production via the steam reforming of methane (SRM) including integrated catalyst regeneration. In order to study the effect of the contact mode, the oxidative SRM has been carried out over a Ni/Al 2 O 3 catalyst using a fixed Bed Reactor (fBR), a conventional Fluidized-Bed Reactor (FBR) and the proposed two-zone Fluidized Bed Reactor (TZFBR). The technical feasibility of these Reactors has been studied experimentally, investigating their performance (CH 4 conversion, CO and H 2 selectivity, and H 2 global yield) and stability under different operating conditions. Coke generation in the process has been verified by several techniques. A stable performance was obtained in the TZFBR, where coke formation was counteracted with continuous catalyst regeneration. The viability of the TZFBR for carrying out this process with a valuable global yield to hydrogen is demonstrated.
-
stable hydrogen production by methane steam reforming in a two zone Fluidized Bed Reactor effect of the operating variables
International Journal of Hydrogen Energy, 2013Co-Authors: L Perezmoreno, Javier Herguido, J Soler, M MenendezAbstract:Abstract The oxidative steam reforming of methane in a two-zone Fluidized-Bed Reactor (TZFBR) was investigated over a Ni/Al 2 O 3 catalyst. The effects of the main operating variables (temperature, steam/oxygen ratio, steam/methane ratio and relative velocity with respect to the minimum fluidization velocity) have been studied. A comparison has been made with results given in the literature in terms of hydrogen yield. Despite working with very low steam/methane ratios, high values of hydrogen yield at both high methane conversion and at steady state were obtained in the TZFBR.
-
stable steam reforming of ethanol in a two zone Fluidized Bed Reactor
Industrial & Engineering Chemistry Research, 2012Co-Authors: L Perezmoreno, Javier Herguido, J Soler, M MenendezAbstract:The oxidative steam reforming of ethanol in a two-zone Fluidized-Bed Reactor (TZFBR) and in a conventional Fluidized-Bed Reactor over a Ni/Al 2 O 3 catalyst has been investigated. Catalyst deactivation has been studied for both contact modes. Coke generation has been verified by several techniques, and a stable performance was obtained in the TZFBR, where coke formation was counteracted with continuous catalyst regeneration. The effects of the main operating variables (steam/ethanol ratio S/E, oxygen/ethanol ratio O/E, temperature, and relative velocity with respect to the minimum fluidization velocity) have been studied. Both stable results and continuous operation without catalyst deactivation were achieved in the TZFBR in a wide range of S/E values, showing its viability for carrying out this process. High hydrogen selectivity with total conversion of ethanol was achieved even at low S/E and O/E ratios.
Jae Hyung Choi - One of the best experts on this subject based on the ideXlab platform.
-
upgrading bio oil by catalytic fast pyrolysis of acid washed saccharina japonica alga in a Fluidized Bed Reactor
Renewable Energy, 2019Co-Authors: Jae Hyung Choi, Hee Chul Woo, Seungsoo Kim, Jinsoo KimAbstract:Abstract Macroalgae contain significant amounts of inorganic compounds (K, Na, Mg, and Ca) that cause problems during thermal processing (ash fouling or agglomeration of char and Bed material). The macroalga Saccharina japonica (S.J) was demineralized with diluted acid solution to remove inorganic species before using this matter for fast pyrolysis in a bubbling Fluidized-Bed Reactor. The effect of acid washing on the product yield and the quality of bio-oil was systematically investigated. When the pyrolysis temperature increased from 400 to 500 °C, the bio-oil yield was 39.70–45.36 wt%. The major compounds in the bio-oil were levoglucosan and di-anhydromannitol. The fractional catalytic pyrolysis of pre-treated S. japonica using HZSM-5 catalyst (calcined at 550 °C) was investigated in Fluidized-Bed Reactor under the same conditions. Pyrolysis of the pretreated sample with catalyst resulted in 35.37–39.05 wt% liquid yield, which was lower than that from using silica sand. Using HZSM-5 catalytic pyrolysis bio-oil showed a decrease in dianhydromannitol and 2-furyl methyl ketone, and an increase in aromatic compounds such as derivatives of phenol, indole, and naphthalene. The effect of pretreatment by acid washing, and the effect of this catalyst on the pyrolysis product distribution and composition were clarified in relation to previous work.
-
effects of water washing saccharina japonica on fast pyrolysis in a bubbling Fluidized Bed Reactor
Biomass & Bioenergy, 2017Co-Authors: Jae Hyung Choi, Hoang Vu LyAbstract:Abstract The pyrolysis characteristics of non-edible Saccharina japonica ( S. japonica ) obtained from an offshore high-density aquaculture facility were systematically investigated using a thermogravimetric analyzer and a bubbling Fluidized-Bed Reactor. As high mineral contents in S. japonica cause ash fouling or agglomeration of char and Bed material in Fluidized-Bed Reactor, S. japonica was water-washed as pre-treatment to remove minerals and sticky materials. The pretreated S. japonica samples were mostly decomposed between 200 and 350 °C at heating rates of 5–20 °C/min. The calculated activation energy increased from 36.31 to 393.01 kJ/mol when pyrolysis conversion increased from 5 to 60%. The yields of bio-oil were 25.57–31.27 wt% under the investigated pyrolysis conditions (temperature: 350–450 °C; fluidization velocity: 2.0 × U mf − 4.5 × U mf ). The highest bio-oil yield (31.27 wt%) from water-washed S. japonica was obtained at 375 °C and 4.0 × U mf , and the HHVs of the organic and aqueous phases in the bio-oil were 31.47 and 5.41 MJ/kg, respectively. The major compounds in the bio-oil were analyzed by GC-MS and the carbon number distribution of the bio-oils was determined through simulated distillation by TGA.
Frank Behrendt - One of the best experts on this subject based on the ideXlab platform.
-
euler lagrange dem simulation of wood gasification in a bubbling Fluidized Bed Reactor
Particuology, 2009Co-Authors: Michael Oevermann, Stephan Gerber, Frank BehrendtAbstract:We present an Euler–Lagrange method for the simulation of wood gasification in a bubbling Fluidized Bed. The gas phase is modeled as a continuum using the 2D Navier–Stokes equations and the solid phase is modeled by a Discrete Element Method (DEM) using a soft-sphere approach for the particle collision dynamic. Turbulence is included via a Large-Eddy approach using the Smagorinsky sub-grid model. The model takes into account detailed gas phase chemistry, zero-dimensional modeling of the pyrolysis and gasification of each individual particle, particle shrinkage, and heat and mass transfer between the gas phase and the particulate phase. We investigate the influence of wood feeding rate and compare exhaust gas compositions and temperature results obtained with the model against experimental data of a laboratory scale bubbling Fluidized Bed Reactor.
-
euler lagrange dem simulation of wood gasification in a bubbling Fluidized Bed Reactor
Particuology, 2009Co-Authors: Michael Oevermann, Stephan Gerber, Frank BehrendtAbstract:We present an Euler–Lagrange method for the simulation of wood gasification in a bubbling Fluidized Bed. The gas phase is modeled as a continuum using the 2D Navier–Stokes equations and the solid phase is modeled by a Discrete Element Method (DEM) using a soft-sphere approach for the particle collision dynamic. Turbulence is included via a Large-Eddy approach using the Smagorinsky sub-grid model. The model takes into account detailed gas phase chemistry, zero-dimensional modeling of the pyrolysis and gasification of each individual particle, particle shrinkage, and heat and mass transfer between the gas phase and the particulate phase. We investigate the influence of wood feeding rate and compare exhaust gas compositions and temperature results obtained with the model against experimental data of a laboratory scale bubbling Fluidized Bed Reactor.