scholarly journals Comparison of the Effects of Fluidized-Bed and Fixed-Bed Reactors in Microwave-Assisted Catalytic Decomposition of TCE by Hydrogen

2012 ◽  
Vol 2012 ◽  
pp. 1-4 ◽  
Author(s):  
Lili Ren ◽  
Jin Zhang
Keyword(s):  
Fluidized Bed ◽  
Fixed Bed ◽  
Reaction System ◽  
Catalytic Decomposition ◽  
Fluidized Bed Reactor ◽  
Reaction Systems ◽  
Microwave Assisted ◽  
Fixed Bed Reactors ◽  
Catalyst Type ◽  
Interactive Relationship

Trichloroethylene (TCE) decomposition by hydrogen with microwave heating under different reaction systems was investigated. The activities of a series of catalysts for microwave-assisted TCE hydrodechlorination were tested through the fixed-bed and the fluidized-bed reactor systems. This study found that the different reaction system is suitable for different catalyst type. And there is an interactive relationship between the catalyst type and the reaction bed type.

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.

scholarly journals Numerical Investigation of Process Enhancement Using a Bifunctional Catalyst in a Dual Fluidized-Bed Reactor

Catalysts ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 530
Author(s):  
Katarzyna Bizon ◽  
Krzysztof Skrzypek-Markiewicz ◽  
Mateusz Prończuk
Keyword(s):  
Fluidized Bed ◽  
Chemical Reaction ◽  
Active Sites ◽  
Physical Adsorption ◽  
Equilibrium Constants ◽  
Fixed Bed ◽  
Process Intensification ◽  
Fluidized Bed Reactor ◽  
Adsorption Sites ◽  
Dual Fluidized Bed

The paper outlines the concept of process intensification and integration, with a particular focus on sorption-enhanced, solid-catalyzed chemical processes. An alternative and attractive solution to a system of parallel fixed-bed apparatuses is evaluated, which utilizes the solids’ circulation in a dual fluidized-bed reactor–regenerator system. This allows for continuous mode operation and greatly simplifies the control procedures. To illustrate some aspects related to the steady-state operation of such a dual system, a simplified mathematical model of two interconnected fluidized beds operating in the bubbling regime was developed. A generic reversible chemical reaction of the overall second-order, catalyzed by bifunctional pellets, integrating catalytic active sites and adsorption sites, was considered as a test case. The model was used to study the effects of the bed hydrodynamics, as well as of the chemical reaction and physical adsorption equilibrium constants. It was shown how the superposition of various chemical, physical and hydrodynamical phenomena affects the performance of the system.

scholarly journals Efficient plasma-catalysis coupling for CH4 and CO2 transformation in a fluidized bed reactor: Comparison with a fixed bed reactor

Fuel ◽  
2021 ◽  
Vol 288 ◽  
pp. 119575
Author(s):  
Nassim Bouchoul ◽  
Houcine Touati ◽  
Elodie Fourré ◽  
Jean-Marc Clacens ◽  
Catherine Batiot-Dupeyrat
Keyword(s):  
Fluidized Bed ◽  
Fixed Bed ◽  
Fluidized Bed Reactor ◽  
Fixed Bed Reactor ◽  
Plasma Catalysis ◽  
Co2 Transformation

Modeling of transport phenomena in fixed-bed reactors for the Fischer-Tropsch reaction: a brief literature review

2017 ◽  
Vol 33 (2) ◽  
Author(s):  
José R.G. Sánchez-López ◽  
Angel Martínez-Hernández ◽  
Aracely Hernández-Ramírez
Keyword(s):  
Liquid Fuel ◽  
Transport Phenomena ◽  
Fixed Bed ◽  
Reaction System ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Fuel Production ◽  
Fischer Tropsch ◽  
Fixed Bed Reactors ◽  
The Impact

AbstractCurrently, few processes can be considered practical alternatives to the use of petroleum for liquid fuel production. Among these alternatives, the Fischer-Tropsch synthesis (FTS) reaction has been successfully applied commercially. Nevertheless, many of the fundamentals of this process are difficult to understand because of its complexity, which depends strongly on the catalyst and the reactor design and operating conditions, as the reaction is seriously affected by mass and heat transport issues. Thus, studying this reaction system with transport phenomena models can help to elucidate the impact of different parameters on the reaction. According to the literature, modeling FTS systems with 1D models provides valuable information for understanding the phenomena that occur during this process. However, 2D models must be used to simulate the reactor to correctly predict the reactor variables, particularly the temperature, which is a critical parameter to achieve a suitable distribution of products during the reaction. Thus, this work provides a general resume of the current findings on the modeling of transport phenomena on a particle/pellet level in a tubular fixed-bed reactor.

Refinery Oil Fraction Fuels Obtained from Polyethylene Catalytic Cracking Employing Heteropolyacid-MCM-41 Materials

2010 ◽  
Vol 132 ◽  
pp. 236-245 ◽  
Author(s):  
Alberto Hernández ◽  
Luis E. Noreña-Franco ◽  
Li Fang Chen ◽  
Jin An Wang ◽  
Julia Aguilar
Keyword(s):  
Fixed Bed ◽  
Reaction System ◽  
Catalytic Decomposition ◽  
Tungstophosphoric Acid ◽  
Fixed Bed Reactor ◽  
Technical Approach ◽  
Ordered Mesoporous Materials ◽  
Oil Fraction ◽  
Ordered Mesoporous ◽  
Mcm 41

We report the thermal and catalytic decomposition of low density polyethylene (LDPE) as a recycling route of plastic solid waste. The reaction system consisted of a fixed-bed reactor at a 450 °C reaction temperature and a 40 min reaction time. Tungstophosphoric acid (H3PW12O40)-functionalized ordered mesoporous materials MCM-41 were employed as catalysts. Results show that using this technical approach, on one hand, environmentally unfriendly waste can be disposed and, on the other hand, valuable and widely used fuels can be obtained.

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