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Degradation of whey in an anaerobic fixed bed (AnFB) reactor

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Book Series: Karlsruher Berichte zur Ingenieurbiologie ISSN: 1728709 ISBN: 3937300120 Year: Volume: 41 Pages: XIII, 135 p. DOI: 10.5445/KSP/1592004 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Physics (General)
Added to DOAB on : 2019-07-30 20:02:02

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An Anaerobic Fixed Bed (AnFB) reactor was run as an upflow anaerobic reactor with an arrangement of supporting material for growth of a biofilm. The supporting material was made from Liapor-clay-polyethylene sinter lamellas (Herding Co., Amberg).The AnFB reactor was used for treating high concentrations of whey-containing wastewater. Optimal operating conditions for whey treatment at a concentration of COD in the influent of around 50 g whey·l-1 were found for a hydraulic retention time (HRT) in the range of 4-8 days or an organic loading rate (OLR) less than 10 kg COD·m-3·d-1. This is a higher load than normally applied in praxis reactors.Accumulation of volatile fatty acids (VFAs) happened when the AnFB was supplied with surplus whey solution at a high OLR or when it was oxygenated. VFAs were accumulated faster when the HRT was changed from 12 days to 6 days compared to a change of HRT from 6 days to 4 days. However, at a HRT of 6 days, the accumulated VFAs were completely degraded after an adaptation period of about 5 days, whereas the accumulated VFAs at a HRT of 4 days remained constant upon time and could not be degraded during further incubation.The conversion process (acetogenesis and methanogenesis) of VFAs was influenced by the pH in the reactor. Acetate and n-Butyrate were converted faster at neutral or slightly alkaline pH, while propionate was degraded faster at slightly acidic pH-value. The population in the AnFB contained hydrogen-utilizing methanogenic bacteria, formate-utilizing methanogenic bacteria, methanol-utilizing methanogenic bacteria, acetoclastic methanogenic bacteria and sulfate-reducing bacteria as the final-stage organism of whey degradation. Acetogenic and methanogenic bacteria grew slower and were present at much lower numbers than acidogenic bacteria. This made the acid degradation rate less than the acid production rate. The minimal HRT in the whey reactor was thus dependent on acid degradation rates. Acetate-utilizing methanogens seemed to be unable to grow as single cells. They preferred to grow in a particulate or attached manner on a support material. The biofilm on the support materials provided a lower redox potential and an anaerobic environment that was obligately needed by these bacteria. The addition of a reducing agent was necessary to keep the few culturing acetoclastic methanogens in suspended cultures active.H2/CO2 was the best methanogenic substrate for the bacteria in the effluent suspension of whey reactor, followed by formate and methanol. The least degradable substrate in suspension cultures was acetate. The optimal H2 gas concentration for methanogens was provided at 2.25 bar.Ferric ions addition or the addition of a mix of minerals improved acetate degradation and methane production rates more than two-folds. The redox potential + reducing agent was low enough for methanogenesis. An AnFB-reactor would be a suitable means for stabilizing wastewater from dairy processing. Liapor-clay-polyethylene sinter lamellas in a regularly arrangement could be the substratum for biofilm formation. A minimum HRT of 4-6 days should be planned or a maximum OLR rate 10 kg COD·m-3·d-1 not exceeded.

High Performance Light Water Reactor : Design and Analyses

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ISBN: 9783866448179 Year: Pages: X, 241 p. DOI: 10.5445/KSP/1000025989 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:01:59
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The High Performance Light Water Reactor is a nuclear reactor concept of the 4th generation which is cooled and moderated with supercritical water. The concept has been worked out by a consortium of European partners, co-funded by the European Commission. It features a once through steam cycle, a pressure vessel type reactor, and a compact containment with pressure suppression pool. The conceptual design enables to assess its feasibility, its safety features and its economic potential.

Investigation of Fretting Wear of Cladding Materials in Liquid Lead

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Book Series: Karlsruher Forschungsberichte aus dem Institut für Hochleistungsimpuls- und Mikrowellentechnik ISSN: 21922764 ISBN: 9783866449602 Year: Volume: 3 Pages: XV, 246 p. DOI: 10.5445/KSP/1000031949 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:02:01
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One promising concept for future nuclear reactors uses liquid metals like Pb as reactor coolant. In this work, fretting of fuel clad materials is investigated in Pb environment at relevant operating conditions. A novel test apparatus is presented that allows fretting tests in liquid lead with high accuracy and reproducibility also during long term tests. Tolerable operating conditions concerning fretting wear by evaluating the specific wear coefficient and the concept of fretting maps are given.

Partial oxidation of Raffinate II and other mixtures of n-Butane and n-Butenes to maleic anhydride in a fixed-bed reactor

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ISBN: 9783866441996 Year: Pages: VI, 186 p. DOI: 10.5445/KSP/1000007336 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Chemical Engineering
Added to DOAB on : 2019-07-30 20:02:01
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The utilisation of the C4 streams of steamcrackers by converting raffinate II to maleic anhydride was studied. The oxidation reactions were investigated in a laboratory-scale fixed-bed reactor to determine reaction kinetics. The effects of pore diffusional resistance were investigated and explained. A two-dimensional pseudo-homogeneous reactor model was used for the simulation of a production-scale fixed-bed reactor. A flow scheme of the reactor section including a recycle was proposed.

In-situ H2O removal via hydorphilic membranes during Fischer-Tropsch and other fuel-related synthesis reactions

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ISBN: 9783866446403 Year: Pages: IV, 244 p. DOI: 10.5445/KSP/1000022232 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Chemical Engineering
Added to DOAB on : 2019-07-30 20:01:57
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The general objective of this thesis was to explore the potential of in-situ H2O removal during fuel-related synthesis reactions with focus on in-situ H2O removal by hydrophilic membranes and by chemical reaction. It is demonstrated that in-situ H2O removal through vapour permeation during CO2 hydrogenation to Fischer-Tropsch hydrocarbons and during DME/DEE synthesis leads to increased conversion and yield levels, which are directly linked to the degree of H2O recovery.

Characterization of High Temperature Superconductor Cables for Magnet Toroidal Field Coils of the DEMO Fusion Power Plant

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Book Series: Karlsruher Schriftenreihe zur Supraleitung / Hrsg. Prof. Dr.-Ing. M. Noe, Prof. Dr. rer. nat. M. Siegel ISSN: 18691765 ISBN: 9783731506058 Year: Volume: 18 Pages: VII, 198 p. DOI: 10.5445/KSP/1000062054 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Physics (General)
Added to DOAB on : 2019-07-30 20:01:58
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Nuclear fusion is a key technology to satisfy the basic demand for electric energy sustainably. The official EUROfusion schedule foresees a first industrial DEMOnstration Fusion Power Plant for 2050. In this work several high temperature superconductor sub-size cables are investigated for their applicability in large scale DEMO toroidal field coils. Main focus lies on the electromechanical stability under the influence of high Lorentz forces at peak magnetic fields of up to 12 T.

Numerical Modeling of Stagnation Flows over Porous Catalytic Surfaces

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ISBN: 9783731504344 Year: Pages: XII, 204 p. DOI: 10.5445/KSP/1000049629 Language: ENGLISH
Publisher: KIT Scientific Publishing
Subject: Technology (General)
Added to DOAB on : 2019-07-30 20:02:00
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In this book, stagnation flows on a catalytic porous plate is modeled one-dimensionally coupled with multi-step surface reaction mechanisms and molecular transport (diffusion and conduction) in the flow field and in the porous catalyst. Internal and external mass transfer limitations as well as possible reaction routes in the catalyst are investigated for CO oxidation, WGS reaction, partial and steam reforming of methane over Rh/Al?O?.

Pd-based Membranes. Overview and Perspectives

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ISBN: 9783038977025 Year: Pages: 190 DOI: 10.3390/books978-3-03897-703-2 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Chemical Engineering --- Technology (General)
Added to DOAB on : 2019-04-05 10:34:31
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Palladium (Pd)-based membranes have received a great deal of attention from both academia and industry thanks to their ability to selectively separate hydrogen from gas streams. The integration of such membranes with appropriate catalysts in membrane reactors allows for hydrogen production with CO2 capture that can be applied in smaller bioenergy or combined heat and power (CHP) plants, as well as in large-scale power plants. Pd-based membranes are therefore regarded as a Key Enabling Technology (KET) to facilitate the transition towards a knowledge-based, low-carbon, and resource-efficient economy. This Special Issue of the journal Membranes on “Pd-based Membranes: Overview and Perspectives” contains nine peer-reviewed articles. Topics include manufacturing techniques, understanding of material phenomena, module and reactor design, novel applications, and demonstration efforts and industrial exploitation.

Membrane and Membrane Reactors Operations in Chemical Engineering

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ISBN: 9783039210220 9783039210237 Year: Pages: 154 DOI: 10.3390/books978-3-03921-023-7 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering --- Environmental Engineering
Added to DOAB on : 2019-06-26 10:09:00
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This Special Issue is aimed at highlighting the potentialities of membrane and membrane reactor operations in various sectors of chemical engineering, based on application of the process intensification strategy. In all of the contributions, the principles of process intensification were pursued during the adoption of membrane technology, demonstrating how it may lead to the development of redesigned processes that are more compact and efficient while also being more environmental friendly, energy saving, and amenable to integration with other green processes. This Special Issue comprises a number of experimental and theoretical studies dealing with the application of membrane and membrane reactor technology in various scientific fields of chemical engineering, such as membrane distillation for wastewater treatment, hydrogen production from reforming reactions via inorganic membrane and membrane photoassisted reactors, membrane desalination, gas/liquid phase membrane separation of CO2, and membrane filtration for the recovery of antioxidants from agricultural byproducts, contributing to valorization of the potentialities of membrane operations.

Multiscale and Innovative Kinetic Approaches in Heterogeneous Catalysis

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ISBN: 9783039211791 9783039211807 Year: Pages: 214 DOI: 10.3390/books978-3-03921-180-7 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2019-08-28 11:21:27
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Kinetics and reactor modeling for heterogeneous catalytic reactions are prominent tools for investigating and understanding catalyst functionalities at nanoscale and the related rates of complex reaction networks. This book illustrates some examples related to the transformation of simple to more complex feedstocks, including different types of reactor designs, i.e., steady-state, transient plug flow reactors, and TAP reactors for which there is sometimes a strong gap in the operating conditions from ultra-high-vacuum to high-pressure conditions. In conjunction, new methodologies have emerged, giving rise to more robust microkinetics models. As exemplified, they include the kinetics and the dynamics of the reactors and span a large range of length and time scales. The objective of this Special Issue is to provide contributions that can illustrate recent advances and novel methodologies for elucidating the kinetics of heterogeneous reactions and the necessary multiscale approach for optimizing the reactor design. This book is dedicated to postgraduate and scientific researchers, and experts in heterogeneous catalysis. It may also serve as a source of original information for the elaboration of lessons on catalysis for Master students.

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