Preparation of Mo/HZSM-5/Bentonite Catalyst for Methane Aromatization in a Fluidized Bed Reactor

2017 ◽  
Vol 15 (5) ◽  
Author(s):  
J Lasobras ◽  
J.A Medrano ◽  
J Soler ◽  
J Herguido ◽  
M Menéndez ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Mechanical Stability ◽  
Active Material ◽  
Fluidized Bed Reactor ◽  
Added Value ◽  
Fluidized Bed Reactors ◽  
Thermal Treatments ◽  
Methane Aromatization ◽  
Catalyst Synthesis ◽  
Aromatization Reaction

Abstract Methane aromatization is a promising technology for the transformation of natural gas to added-value products. The main objective of this work was to obtain a catalyst with suitable performance and good mechanical stability for methane aromatization reaction in fluidized bed reactors. The selected catalyst was Mo/H-ZSM-5/bentonite mixture. Mo/ZSM-5 was chosen as the active material, since it provides good selectivity to aromatics but the particle size of the zeolite was too small for operation in a fluidized bed and a binder was needed. We prepared two series of catalysts with two different zeolites. We tested several heating velocities (1, 7 and 10 °C min‒1) in the different stages of catalyst synthesis. Methane conversion and selectivity to aromatic products improved when using gentle thermal treatments, increasing 2% and 10%, respectively, for the best catalyst tested.

Influence of Seeding Conditions on Initial Biofilm Development during the Startup of Anaerobic Fluidized Bed Reactors

1989 ◽  
Vol 21 (4-5) ◽  
pp. 157-165 ◽  
Author(s):  
F. Ehlinger ◽  
J. M. Audic ◽  
G. M. Faup
Keyword(s):  
Fluidized Bed ◽  
Future Development ◽  
Protein Concentration ◽  
Specific Activity ◽  
Fluidized Bed Reactor ◽  
Fluidized Bed Reactors ◽  
Support Material ◽  
Biofilm Development ◽  
Initial Biofilm

The characterization of the biofilm of an anaerobic fluidized-bed reactor was completed under standard conditions. The distribution of the fixed protein concentration depended on the level in the reactor. The protein concentration reached 1520 µg.g−1 of support at the top of the reactor and only 1200 µg.g−1 at the bottom after 504 hours of operation but the specific activity of the biofilm was 33×10−4 µM acetate.h−1.mg−1 proteins at the bottom and only 26×10−4 µM.h−1.mg−1 at the top. The efficiency of a fluidized bed reactor and the composition of the biofilm changed with an increase of the pH from 7 to 8.5 during the seeding of the support material. Future development of the biofilm and the specific activity of the support were affected.

scholarly journals Methane Aromatization in a Fluidized Bed Reactor: Parametric Study

2020 ◽  
Author(s):  
Javier Lasobras ◽  
Jaime Soler ◽  
Javier Herguido ◽  
Miguel Menéndez ◽  
Alonso Jimenez ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Parametric Study ◽  
Fluidized Bed Reactor ◽  
Methane Aromatization

Development of a Continuous Fluidized Bed Reactor for Thermochemical Energy Storage Application

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Manuel Wuerth ◽  
Moritz Becker ◽  
Peter Ostermeier ◽  
Stephan Gleis ◽  
Hartmut Spliethoff
Keyword(s):  
Energy Storage ◽  
Fluidized Bed ◽  
State Of The Art ◽  
Scale Up ◽  
Fixed Bed ◽  
Fluidized Bed Reactor ◽  
Fluidized Bed Reactors ◽  
Heat Of Reaction ◽  
Reaction Systems

Thermochemical energy storage (TCES) represents one of the most promising energy storage technologies, currently investigated. It uses the heat of reaction of reversible reaction systems and stands out due to the high energy density of its storage materials combined with the possibility of long-term storage with little to no heat losses. Gas–solid reactions, in particular the reaction systems CaCO3/CaO, CaO/Ca(OH)2 and MgO/Mg(OH)2 are of key interest in current research. Until now, fixed bed reactors are the state of the art for TCES systems. However, fluidized bed reactors offer significant advantages for scale-up of the system: the improved heat and mass transfer allows for higher charging/discharging power, whereas the favorable, continuous operation mode enables a decoupling of storage power and capacity. Even though gas–solid fluidized beds are being deployed for wide range of industrial operations, the fluidization of cohesive materials, such as the aforementioned metal oxides/hydroxides, still represents a sparsely investigated field. The consequent lack of knowledge of physical, chemical, and technical parameters of the processes on hand is currently a hindering aspect for a proper design and scale-up of fluidized bed reactors for MW applications of TCES. Therefore, the experimental research at Technical University of Munich (TUM) focuses on a comprehensive approach to address this problem. Preliminary experimental work has been carried out on a fixed bed reactor to cover the topic of chemical cycle stability of storage materials. In order to investigate the fluidization behavior of the bulk material, a fluidized bed cold model containing a heat flux probe and operating at atmospheric conditions has been deployed. The experimental results have identified the heat input and output as the most influential aspect for both the operation and a possible scale-up of such a TCES system. The decisive parameter for the heat input and output is the heat transfer coefficient between immersed heat exchangers and the fluidized bed. This coefficient strongly depends on the quality of fluidization, which in turn is directly related to the geometry of the gas distributor plate. At TUM, a state-of-the-art pilot fluidized bed reactor is being commissioned to further investigate the aforementioned aspects. This reactor possesses an overall volume of 100 L with the expanded bed volume taking up 30 L. Two radiation furnaces (64 kW) are used to heat the reactor. The heat of reaction of the exothermal hydration reaction is removed by water, evaporating in a cooling coil, immersed in the fluidized bed. Fluidization is being achieved with a mixture of steam and nitrogen at operating temperatures of up to 700 °C and operating pressures between −1 and 6 bar(g). The particle size is in the range of d50 = 20 μm. While initial experiments on this reactor focus on optimal operating and material parameters, the long-term goal is to establish correlations for model design and scale-up purposes.

Aerobic and Anaerobic Biotransformations and Treatment of Chlorinated Pulp Bleach Waste Constituents

1994 ◽  
Vol 29 (5-6) ◽  
pp. 73-80 ◽  
Author(s):  
Jaakko A. Puhakka ◽  
Päivi M. Mäkinen ◽  
Margareta Lundin ◽  
John F. Ferguson
Keyword(s):  
Fluidized Bed ◽  
Continuous Flow ◽  
Fluidized Bed Reactor ◽  
High Rate ◽  
Fluidized Bed Reactors ◽  
Chlorinated Phenols ◽  
Anaerobic Fluidized Bed Reactor ◽  
Inorganic Chloride ◽  
Aerobic And Anaerobic ◽  
Complete Dechlorination

Biotransformations and treatment of several chlorinated, hydroxylated and methoxylated monoaromatic compounds were studied in batch bottle bioassays and continuous-flow fluidized-bed reactors. With the aerobic enrichment, polychlorinated phenols were biodegraded with simultaneous release of inorganic chloride in amounts equal to mineralization stoichiometrics. Aerobic removal of 4,5-dichlorocatechol and 4,5- dichlorovanillin were associated with the release of inorganic chlorine. The aerobic enrichment showed no activity against mono- or di-O-methylated phenols. With the anaerobic enrichment, reductive transformations of these compounds were observed. These transformations included reductive dechlorinations, de-O-methylations and dehydroxylations. High-rate operation of an aerobic fluidized-bed reactor resulted in over 99.7% biodégradation of polychlorophenols. In the anaerobic fluidized-bed reactor, over 95% removal of chlorophenols with no apparent accumulation of lower chlorinated phenols indicated complete dechlorination.

scholarly journals DEVELOPMENT AND VERIFICATION OF APPROPRIATENESS FOR MATHEMATICAL MODEL OF HEAT BALANCE OF ELECTROTHERMAL FLUIDIZED BED REACTOR

2018 ◽  
Vol 41 (2) ◽  
pp. 35-40
Author(s):  
K.V. Simeiko
Keyword(s):  
Mathematical Model ◽  
Fluidized Bed ◽  
Thermal Efficiency ◽  
Heat Balance ◽  
Fluidized Bed Reactor ◽  
Fluidized Bed Reactors ◽  
Average Deviation ◽  
Model Average ◽  
Thermochemical Process ◽  
Experimental Values

Supply of heat through combustion of organic fuel is impossible or economically unviable for the raw of high temperature processes due to it’s technological peculiarities. Some of these processes can be carried out in electrothermal fluidized bed reactors. Development of appropriate mathematical model for heat balance will allow prognostication of capacity needed to carry out specific process and improvement of electrothermal fluidized bed reactor. During the development of mathematical model methods of heat-mass exchange theory were applied.  Verification of appropriateness for mathematical model was carried out through comparison of experimental results and calculated values of the amount of heat needed to perform the process of methane pyrolysis in electrothermal fluidized bed and coefficient of thermal efficiency of electrothermal fluidized bed reactor. Comparison with real thermochemical process in electrothermal fluidized bed reactor confirms the appropriateness of mathematical model. Average deviation of mathematical model of heat balance and coefficient of thermal efficiency from obtained experimental values is 5…7 % and 6…9 % respectively. Proposed mathematical model can be applied in design of electrothermal fluidized bed reactors.

CFD Analysis of a Fluidized Bed Reactor for Industrial Application

2014 ◽  
Author(s):  
Anna Vaccari ◽  
Michele Pinelli ◽  
Luca Pirani ◽  
Nicola Gandolfi
Keyword(s):  
Fluidized Bed ◽  
High Speed ◽  
Fluid Dynamic ◽  
Fluidized Bed Reactor ◽  
Sensitivity Analyses ◽  
Fluidized Bed Reactors ◽  
Test Case ◽  
Energy Applications ◽  
Reactor Geometry ◽  
Pharmaceutical Industries

The fluidized bed reactors are widely used in chemical, mining and pharmaceutical industries and energy applications because of the low pressure drop, the uniform distribution of temperature and of high-speed mass transfer of energy and speed. Fluidization behavior depends on the reactor geometry and internals as well as the particle size distribution and physical properties of the process material. This paper presents a 3D fluid dynamic simulation of a fluidized bed reactor for the pharmaceutical processing of powder, such as mixing, granulation and drying. Firstly, sensitivity analyses based on a literature test-case were performed, for the validation of the computational model and the development of the additional components required for the simulation of a real fluidized bed reactor. Then an unsteady URANS 3D simulation of a modular laboratory-scale fluid bed reactor, product of IMA S.p.A. Active Division, was performed to evaluate the velocity field and particle distribution of the powder involved in the mixing process.

scholarly journals Modeling of metallocene catalyzed propylene polymerization in fluidized bed reactors

2019 ◽  
Vol 268 ◽  
pp. 02002
Author(s):  
Chew-Sang Law ◽  
Mohd Azlan Hussain
Keyword(s):  
Fluidized Bed ◽  
Mixed Model ◽  
Monomer Concentration ◽  
Fluidized Bed Reactor ◽  
Propylene Polymerization ◽  
Fluidized Bed Reactors ◽  
Multi Scale ◽  
Reactor Temperature ◽  
Mixed Reactor ◽  
Reactor Models

A study was performed to improve the model for metallocene catalyzed polyolefin polymerization in fluidized bed reactor by adapting multi-scale modeling approach. Monomer concentration and reactor temperature was predicted using kinetic model of polypropylene homopolymerization coupled with well mixed reactor models of fluidized bed reactor. Well mixed model typically used for Ziegler-Nata was selected as supported homogeneous metallocene exhibited heterogeneous property similar to ZN catalyst. Result of simulation showed that model was able to predict reaction temperature accurate with around 3% over-prediction of reactor temperature, which is more accurate than previous model. Model predicted decrease in final monomer concentration from 0.9929 mol/s to 0.986 mol/s when initial reactor was raised from 25C to 75C.

Modelling of Fluidized Bed Reactors

2003 ◽  
Vol 1 (1) ◽  
Author(s):  
Joachim Werther ◽  
Ernst-Ulrich Hartge
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Fluidized Bed ◽  
Residence Time ◽  
Time Distribution ◽  
Residence Time Distribution ◽  
Scale Up ◽  
Fluidized Bed Reactor ◽  
Fluidized Bed Reactors ◽  
Model Calculations

The fluidized bed reactor has a lot of advantages: excellent gas-solid contacting, no hot spots even with highly exothermal reactions, good gas-to-particle and bed-to-wall heat transfer and the ease of solids handling which is particularly important if the catalyst is quickly ageing. However, the list of disadvantages is as long: broad residence time distribution of the gas due to dispersion and gas-bypass in the form of bubbles, broad residence time distribution of solids due to intense mixing, erosion of bed internals and the attrition of the catalyst particles. A particular disadvantage of the fluidized bed reactor is its difficult scale-up. The historical experience with the FCC process is that in the early 40's of the last century this process was successfully scaled up from a 5 cm dia. pilot-scale unit to a 4.5 m dia. bed in the production unit. On the other hand, around 1950 the scale up of the Fischer-Tropsch synthesis in the fluidized bed failed completely. Modern process design should be able to avoid such disasters by making use of modeling and simulation tools. However, a modeling tool which is really helpful in planning and designing of an industrial fluidized bed reactor has to fulfill a lot of requirements. It should be able to describe the influence of the several changes which are typical for the scale-up process, for example enlargement of bed diameter, bed height and fluidizing velocity, changes of gas distributor design, introduction of in-bed heat exchanger tubes and baffles. In the present work a modelling approach is presented which is able to handle the most important aspects of industrial fluidized bed reactors. A particular focus is to describe the relationship between catalyst attrition, solids recovery in the reactor system and chemical performance of the fluidized bed reactor. The competing influences of attrition of the catalyst particles and efficiency of the solids recovery lead to the establishment of a catalyst particle size distribution (PSD) in the bed inventory which in turn influences via the hydrodynamic characteristics of the fluidized bed the performance of the chemical reactor. The usefulness of this approach is illustrated with model calculations for a fictituous first order reaction where the fluidized bed is equipped with different solids recovery systems including one single stage cyclone, several cyclones in parallel, two- and three-stage cyclone systems, respectively. Model calculations illustrate the significance of a high efficiency of the solids recovery in order to keep the fines in the system which is decisive for a high performance of the reactor. The calculations reveal that it may take months until a quasi steady state of the bed particle size distribution is obtained.

Synthesis of Nano-Sized SiOx/C Composite by a Drip Combustion in Fluidized Bed Reactor and Its Electrochemical Properties

2015 ◽  
Vol 1775 ◽  
pp. 13-18 ◽  
Author(s):  
Anara Molkenova ◽  
Seitaro Kato ◽  
Izumi Taniguchi
Keyword(s):  
Fluidized Bed ◽  
Treatment Process ◽  
Active Material ◽  
Volume Ratio ◽  
Precursor Solution ◽  
Fluidized Bed Reactor ◽  
Voltage Range ◽  
Carbon Particles ◽  
Electrochemical Testing ◽  
Final Sample

ABSTRACTNano-sized SiOx/C composite was successfully prepared by drip combustion in a fluidized bed reactor. A mixture of tetraethyl orthosilicate (TEOS) ant kerosene at a 2:3 volume ratio was used as a precursor solution. The synthesis was carried out between 600 °C and 900 °C. The as-prepared powder (600 °C) consists of SiOx and carbon particles which are approximately ranged from 30 to 80 nm. For the nano-sized SiOx/C composite sample, the heat treatment process was introduced to remove incomplete combustion materials and the dry ball milling was performed to homogenize the distribution of carbon inside the sample. The final sample (nano-sized SiOx/C nanocomposite) was used as an electrode active material and then electrochemical testing was performed. The cell exhibited discharge and charge capacities of 1158 and 533 mAh g-1, respectively, at current density of 50 mAh g-1 in the voltage range between 0.01-3 V versus Li/Li+.

scholarly journals Methane Aromatization in a Fluidized Bed Reactor: Parametric Study

2019 ◽  
Vol 7 ◽  
Author(s):  
Javier Lasobras ◽  
Jaime Soler ◽  
Javier Herguido ◽  
Miguel Menéndez ◽  
Alonso Jimenez ◽  
...  
Keyword(s):  
Fluidized Bed ◽  
Parametric Study ◽  
Fluidized Bed Reactor ◽  
Methane Aromatization
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