Visar resultat 1 - 5 av 1175 avhandlingar innehållade ordet Kemiteknik.
Sammanfattning : The sulfite pulping process is today practised in only a small number of pulp mills around the globe and the number of sulfite mills that use sodium as the base (cation) is less than five. However, due to the increasing interest in the wood based biorefinery concept, the benefits of sulfite pulping and especially the sodium based variety, has recently gained a lot of interest. LÄS MER
Sammanfattning : The proton exchange membrane (PEM) fuel cell is an electrochemical device that converts chemical energy into electrical energy through two electrocatalytic reactions. The most common catalyst used is platinum on carbon (Pt/C), which has shown the best performance in the fuel cell until now. LÄS MER
Sammanfattning : Rare earth elements (REE) are a group of 17 elements including lanthanides, yttrium and scandium; which are found in a variety of classes of minerals worldwide. The criticality of the application, lack of high grade and economically feasible REE resources and a monopolistic supply situation has raised significant attention in recovery of these metals from low grade ores and waste materials. LÄS MER
Sammanfattning : A potential route for converting different carbon sources (coal, natural gas and biomass) into synthetic fuels is the transformation of these raw materials into synthesis gas (CO and H2), followed by a catalytic step which converts this gas into the desired fuels. The present thesis has focused on two catalytic steps: Fischer-Tropsch synthesis (FTS) and methanation. LÄS MER
Sammanfattning : The electric machine and power electronics in electric and hybrid electric vehicles inevitably cause AC harmonics on the vehicle's DC-link. These harmonics can be partially filtered out by large capacitors, which today are overdimensioned in order to protect the vehicle's battery pack. LÄS MER