scholarly journals Catalytic Oxidation of 4-Hydroxybenzoic Acid on Activated Carbon in Batch Autoclave and Fixed-Bed Reactors

2007 ◽  
Vol 46 (25) ◽  
pp. 8388-8396 ◽  
Author(s):  
Carmen Creanga Manole ◽  
Carine Julcour-Lebigue ◽  
Anne-Marie Wilhelm ◽  
Henri Delmas
Keyword(s):  
Activated Carbon ◽  
Catalytic Oxidation ◽  
Fixed Bed ◽  
Hydroxybenzoic Acid ◽  
Fixed Bed Reactors

Continuous catalytic upgrading of ethanol to n-butanol over Cu–CeO2/AC catalysts

2016 ◽  
Vol 52 (95) ◽  
pp. 13749-13752 ◽  
Author(s):  
Dahao Jiang ◽  
Xianyuan Wu ◽  
Jun Mao ◽  
Jun Ni ◽  
Xiaonian Li
Keyword(s):  
Activated Carbon ◽  
Fixed Bed ◽  
Carbon Support ◽  
Reaction Conditions ◽  
Catalytic Upgrading ◽  
Fixed Bed Reactors

Cu–CeO2/AC catalysts exhibited the highest n-butanol yields (21.6% and nearly 20%) under mild reaction conditions in batch and fixed-bed reactors, respectively, which could be ascribed to the synergy of Cu, CeO2 and the activated carbon support.

scholarly journals Catalytic Wet Air Oxidation of Aqueous Organic Mixtures

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Carmen Creanga Manole ◽  
Catherine Ayral ◽  
Carine Julcour Lebigue ◽  
Anne-Marie Wilhelm ◽  
Henri Delmas
Keyword(s):  
Activated Carbon ◽  
Fixed Bed ◽  
Langmuir Equation ◽  
Catalyst Loading ◽  
Hydroxybenzoic Acid ◽  
Catalytic Wet Air Oxidation ◽  
Air Oxidation ◽  
Wet Air Oxidation ◽  
Organic Mixtures ◽  
Complex Approach

Catalytic Wet Air Oxidation (CWAO) has been investigated for the treatment of water contaminated by 4-hydroxybenzoic acid (4HBA) and equimolar mixture of phenol-4HBA. Both batch measurements for kinetics determination and continuous fixed bed operation have been performed on the same Activated Carbon (AC). After a fast initial deactivation AC was proved stable and efficient at moderate temperature and oxygen pressure, like for phenol degradation.The kinetic study in the case of highly adsorbing material as AC may require complex approach to account for the variation of adsorbed reactants during batch oxidation. Adsorption isotherms at reaction temperature and with aged AC have been obtained according to Langmuir equation and used in 4HBA mass balance to derive more significant kinetic parameters. At high catalyst loading and relatively low pollutant concentration, the variation of 4HBA during the batch may be even higher on the solid than in the aqueous phase.

Tertiary Nitrification Pilot Plants on Parisian Waste Water

1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles
Keyword(s):  
Waste Water ◽  
Metropolitan Area ◽  
Fixed Bed ◽  
Point Of View ◽  
Operating Conditions ◽  
Research Center ◽  
Daily Output ◽  
Practical Point ◽  
Fixed Bed Reactors

The Paris Metropolitan area, which contains over eight million inhabitants, has a daily output of about 3 M cu.meters of wastewater, the purification of which is achieved by SIAAP (Paris Metropolitan Area Sewage Service) in both Achères and Valenton plants. The carbon pollution is eliminated from over 2 M cu.m/day at Achères. In order to improve the quality of output water, its tertiary nitrification in fixed-bed reactors has been contemplated. The BIOFOR (Degremont) and BIOCARBONE (OTV) processes could be tested in semi-industrial pilot reactors at the CRITER research center of SIAAP. At a reference temperature of 13°C, the removed load is approximately 0.5 kg N NH4/m3.day. From a practical point of view, it may be asserted that in such operating conditions as should be at the Achères plant, one cubic meter of filter can handle the tertiary nitification of one cubic meter of purified water per hour at an effluent temperature of 13°C.

Role of filter media in an anaerobic fixed-bed reactor

1995 ◽  
Vol 31 (9) ◽  
pp. 137-144 ◽  
Author(s):  
T. Miyahara ◽  
M. Takano ◽  
T. Noike
Keyword(s):  
Anaerobic Bacteria ◽  
Fixed Bed ◽  
Methanogenic Bacteria ◽  
The Other ◽  
Fixed Bed Reactor ◽  
Filter Media ◽  
Fixed Bed Reactors ◽  
Attached Bacteria ◽  
The Relationship

The relationship between the filter media and the behaviour of anaerobic bacteria was studied using anaerobic fixed-bed reactors. At an HRT of 48 hours, the number of suspended acidogenic bacteria was higher than those attached to the filter media. On the other hand, the number of attached methanogenic bacteria was more than ten times as higher than that of suspended ones. The numbers of suspended and deposited acidogenic and methanogenic bacteria in the reactor operated at an HRT of 3 hours were almost the same as those in the reactor operated at an HRT of 48 hours. Accumulation of attached bacteria was promoted by decreasing the HRT of the reactor. The number of acidogenic bacteria in the reactor packed sparsely with the filter media was higher than that in the closely packed reactor. The number of methanogenic bacteria in the sparsely packed reactor was lower than that in the closely packed reactor.

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.

scholarly journals Hydrodynamics of narrow-tube fixed bed reactors filled with Raschig rings

2020 ◽  
Vol 5 ◽  
pp. 100057 ◽  
Author(s):  
E.M. Moghaddam ◽  
E.A. Foumeny ◽  
A.I. Stankiewicz ◽  
J.T. Padding
Keyword(s):  
Fixed Bed ◽  
Narrow Tube ◽  
Fixed Bed Reactors

scholarly journals Influence of Macroscopic Wall Structures on the Fluid Flow and Heat Transfer in Fixed Bed Reactors with Small Tube to Particle Diameter Ratio

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 689
Author(s):  
Thomas Eppinger ◽  
Nico Jurtz ◽  
Matthias Kraume
Keyword(s):  
Heat Transfer ◽  
Fixed Bed ◽  
Particle Diameter ◽  
Diameter Ratio ◽  
Spherical Particles ◽  
Reactor Wall ◽  
Entry Length ◽  
Fixed Bed Reactors ◽  
Wall Structures ◽  
Small Tube

Fixed bed reactors are widely used in the chemical, nuclear and process industry. Due to the solid particle arrangement and its resulting non-homogeneous radial void fraction distribution, the heat transfer of this reactor type is inhibited, especially for fixed bed reactors with a small tube to particle diameter ratio. This work shows that, based on three-dimensional particle-resolved discrete element method (DEM) computational fluid dynamics (CFD) simulations, it is possible to reduce the maldistribution of mono-dispersed spherical particles near the reactor wall by the use of macroscopic wall structures. As a result, the lateral convection is significantly increased leading to a better radial heat transfer. This is investigated for different macroscopic wall structures, different air flow rates (Reynolds number Re = 16 ...16,000) and a variation of tube to particle diameter ratios (2.8, 4.8, 6.8, 8.8). An increase of the radial velocity of up to 40%, a reduction of the thermal entry length of 66% and an overall heat transfer increase of up to 120% are found.

Sign in / Sign up

Export Citation Format

Share Document