Sökning: "Countercurrent flow"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden Countercurrent flow.

  1. 1. Countercurrent operation in the dilute-acid hydrolysis of cellulose for ethanol production

    Författare :Pär Pettersson; Avdelningen för kemiteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; model; lignocellulose; wood; cellulose; ethanol production; dilute-acid hydrolysis; countercurrent; Kemiteknik och kemisk teknologi; Chemical technology and engineering;

    Sammanfattning : Fuel ethanol can be produced from lignocellulosic materials to replace gasoline and diesel. A crucial step in the production process is the hydrolysis (saccharification) of the material, which can be achieved with dilute acid at high temperature. Unfortunately, sugar is degraded under these severe conditions, and the sugar yield is generally low. LÄS MER

  3. 2. Modeling and Performance Analysis of Alternative Heat Exchangers for Heavy Vehicles

    Författare :Wamei Lin; Värmeöverföring; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Countercurrent flow; Graphite foam; Heat exchanger; Thermal performance; Computational fluid dynamics;

    Sammanfattning : Cross flow heat exchangers made from aluminum are common as radiators in vehicles. However, due to the increasing power requirement and the limited available space in vehicles, it is extremely difficult to increase the size of heat exchangers (HEXs) placed in the front of vehicles. LÄS MER

  4. 3. Analysis of Degradation Products from Wood and Methods for Detoxification of Lignocellulose Hydrolysates

    Författare :Per Persson; Centrum för analys och syntes; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; galactoglucomannan; mass spectrometry; liquid chromatography; sugar degradation; detoxification; fermentation inhibitors; lignocellulose hydrolysates; Ethanol production; softwood; Analytical chemistry; Analytisk kemi; countercurrent supercritical fluid extraction;

    Sammanfattning : In order to produce fuel ethanol from lignocellulose, it is necessary to hydrolyse the sugar-containing constituents hemicellulose and cellulose. During acid hydrolysis, a number of compounds are formed or liberated in addition to the fermentable monomeric sugars. LÄS MER

  5. 4. A numerical investigation of energy conversions in geophysical boundary layers

    Författare :Patrik Andreasson; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Vattenteknik; Water Resources Engineering;

    Sammanfattning : The detailed energy conversions in turbulent geophysical boundary layers are examined and quantified. The governing transport equations are solved by utilizing turbulence modelling. Different turbulence closures have been adopted for the boundary layers examined. LÄS MER

  7. 5. Robust Multi-objective Optimization of Rare Earth Element Chromatography

    Författare :Hans-Kristian Knutson; Avdelningen för kemiteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chromatography; Rare earth elements; Modeling; Multi-objective optimization; Robust optimization; Chromatography; Rare earth elements; Modeling; Multi-objective optimization; Robust optimization;

    Sammanfattning : Rare earth elements comprise the metallic elements known as lanthanides as well as scandium and yttrium. They are extensively used in modern technological industries and are considered as strategic commodities in many countries. LÄS MER