scholarly journals Wetting Fraction in a Tubular Reactor with Solid Foam Packing and Gas/Liquid Co-Current Downflow

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 396
Author(s):  
Iman Mohammed ◽  
Uwe Hampel
Keyword(s):  
Liquid Phase ◽  
Mass Transfer Rate ◽  
Fixed Bed ◽  
Tubular Reactor ◽  
Electrochemical Measurement ◽  
Limiting Current ◽  
Structured Catalysts ◽  
Solid Foams ◽  
Solid Foam ◽  
Wetted Area

The performance of fixed-bed reactors with structured catalysts depends heavily on the gas–liquid–solid contacting pattern. For a broad range of flow conditions, the liquid phase does not cover the solid surface of the packing homogeneously; this is known as partial wetting. The wetting fraction in solid foams was obtained using a modified electrochemical measurement method with adaption of the limiting-current technique in different pre-wetting scenarios. The external wetting fraction, which is defined as fraction of the external solid-foam area covered by the liquid phase to the total external solid-foam area, is directly linked to the overall rate of reaction through the overall liquid mass transfer rate. The wetting fraction decreased with an increase in foam density, a process which was related to decreasing the strut thickness, increasing foam surface area, and consequently, decreasing the wetted area. Additionally, the results indicate that a better distribution of liquid and an increased wetting fraction occurred when a spray nozzle distributor was applied. A new wetting correlation for solid foams is proposed to estimate the wetting fraction with consideration of foam morphology and flow regime.

Modeling of aerated upflow fixed bed reactors for nitrification

1999 ◽  
Vol 39 (4) ◽  
pp. 85-92 ◽  
Author(s):  
J. Behrendt
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Liquid Phase ◽  
Gas Phase ◽  
Fixed Bed ◽  
Fixed Bed Reactor ◽  
Bulk Liquid ◽  
Initial Value ◽  
Fixed Bed Reactors ◽  
Number Of Cells

A mathematical model for nitrification in an aerated fixed bed reactor has been developed. This model is based on material balances in the bulk liquid, gas phase and in the biofilm area. The fixed bed is divided into a number of cells according to the reduced remixing behaviour. A fixed bed cell consists of 4 compartments: the support, the gas phase, the bulk liquid phase and the stagnant volume containing the biofilm. In the stagnant volume the biological transmutation of the ammonia is located. The transport phenomena are modelled with mass transfer formulations so that the balances could be formulated as an initial value problem. The results of the simulation and experiments are compared.

Modeling of a Fixed-Bed Reactor for the Production of Phthalic Anhydride

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Amir Rahimi ◽  
Sogand Hamidi
Keyword(s):  
Phthalic Anhydride ◽  
Fixed Bed ◽  
Tubular Reactor ◽  
Operating Conditions ◽  
Fixed Bed Reactor ◽  
Conversion Degree ◽  
Reactor Length ◽  
Reactor Temperature ◽  
Reported Data ◽  
Reactor Pressure

In this study, the performance of a fixed–bed tubular reactor for the production of phthalic anhydride is mathematically analyzed. The conversion degree and reactor temperature values are compared with the measured one in a tubular reactor applied in Farabi petrochemical unit in Iran as well as reported data in the literature for a pilot plate. The comparisons are satisfactory. The effects of some operating parameters including reactor length, feed temperature, reactor pressure, and existence of an inert in the catalytic bed are investigated. The optimum value of each parameter is determined on the basis of the corresponding operating conditions.

scholarly journals Pyrolysis of Oil Palm Residues in a Fixed Bed Tubular Reactor

2015 ◽  
Vol 03 (04) ◽  
pp. 185-193 ◽  
Author(s):  
Mohammed Isah Yakub ◽  
Abakr Yousif Abdalla ◽  
Kabir Kazi Feroz ◽  
Yusuf Suzana ◽  
Alshareef Ibraheem ◽  
...  
Keyword(s):  
Oil Palm ◽  
Fixed Bed ◽  
Tubular Reactor

scholarly journals Investigation of Copper-supported Ceria Nanofibers for Catalytic Oxidation of Diesel Soot

2021 ◽  
Author(s):  
Dan Bahadur Pal ◽  
Anupama Mishra
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fixed Bed ◽  
Tubular Reactor ◽  
Soot Oxidation ◽  
Diesel Soot ◽  
Air Flow Rate ◽  
Reaction Conditions ◽  
Tight Contact ◽  
Diesel Soot Oxidation ◽  
Working Parameters

Abstract In the present research, CeO2 and CuO/CeO2 nanofibers were synthesized by electrospinning at 12 kV DC by maintaining a tip to collector distance of 10 cm. The morphology of the as-synthesized nanofibers was determined by scanning electron microscopy, and their elemental composition was verified by X-ray photoelectron spectroscopy. The activity of the prepared samples for diesel soot oxidation was determined in a bench-scale fixed bed tubular reactor, and effluent gases were analyzed by online gas chromatography. The variations of working parameters (air flow rate, catalyst-soot ratio, catalyst-soot contact type) were evaluated in a range to optimized reaction conditions for diesel soot oxidation. The catalyst with 40% CuO/CeO2 had the highest surface area, the smallest crystallite size, and the best activity for diesel soot oxidation (tight contact) at Tf = 318oC.

scholarly journals Photocatalytic reactors

2003 ◽  
Vol 5 (3) ◽  
pp. 191-197 ◽  
Author(s):  
M. Bouchy ◽  
O. Zahraa
Keyword(s):  
Liquid Phase ◽  
Mass Balance ◽  
Transport Phenomena ◽  
Fixed Bed ◽  
Specific Rate ◽  
Artificial Light ◽  
Photocatalytic Reactors

Fundamental concepts for the design of photocatalytic reactors are recalled: specific rate, modeling of the distribution of the irradiation, description and modeling of transport phenomena on the macroscopic and macroscopic scales. These are required for establishing the reactor mass balance. A brief survey of various reactors is given for solar or artificial light, gas- or liquid-phase, slurry or fixed-bed.

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