Sökning: "char"

Visar resultat 11 - 15 av 128 avhandlingar innehållade ordet char.

1. 11. Kraft lignin valorization by hydrotreatment over Mo-based sulfided catalysts

   Författare :Muhammad Abdus Salam; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Char; Bio-oil; Kraft Lignin; Hydrodeoxygenation; Y-zeolite; Metal sulfide; Depolymerization; Acidity;

   Sammanfattning : The production of green fuels and chemicals from bio-based feedstock can suppress the dependency on fossil resources and help mitigate global climate challenges. Kraft lignin is a thermochemically modified natural lignin obtained from the pulping process as a byproduct. LÄS MER

3. 12. Solid Fuel Conversion in Dual Fluidized Bed Gasification - Modelling and Experiments

   Författare :Louise Lundberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; dual fluidized bed gasification; fuel mixing; biomass; semi-empirical modelling; char gasification rate; fuel conversion; active bed material; char reactivity;

   Sammanfattning : Dual fluidized bed gasification (DFBG) is the initial step towards the transformation of ligno-cellulosic materials into a raw gas, which can be further upgraded into transportation fuels, such as substitute natural gas, Fischer-Tropsch diesel, dimethyl ether, and methanol. DFBG units can be operated in two distinctly different ways, depending on whether the main product is a gas (to be refined into a transportation fuel) or heat and power (with gas as a by-product). LÄS MER

4. 13. Study of bio-oil and bio-char production from thermal and catalytic hydrotreatment of simulated pyrolysis oil under mild conditions

   Författare :Elham Nejadmoghadam; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Stabilization; soluble solid; alumina-supported catalyst; insoluble solid char; simulated pyrolysis oil; catalytic hydrotreatment;

   Sammanfattning : Pyrolysis oil derived from fast pyrolysis of lignocellulosic biomass is a promising alternative energy source used to produce renewable biofuels. However, the high reactivity of unsaturated oxygenated compounds in pyrolysis oil results in charring and deactivation of the catalyst under severe hydrotreatment conditions. LÄS MER

5. 14. Invasion of top and intermediate consumers in a size structured fish community

   Författare :Per Ask; Lennart Persson; Daniel E Schindler; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Invasion; intraguild predation; size-structure; cannibalism; climate; temperature; Arctic char; ninespine stickleback; Freshwater ecology; Limnisk ekologi; biology; biologi;

   Sammanfattning : In this thesis I have investigated the effects of invading top and intermediate consumers in a size-structured fish community, using a combination of field studies, a lake invasion experiment and smaller scale pond and aquaria experiments. The lake invasion experiment was based on introductions of an intermediate consumer, ninespine stickleback (Pungitius pungitius L. LÄS MER

7. 15. Gasification of biochars: Evolution of pore structure, effects of alkalis and alkali release

   Författare :Saiman Ding; Klas Engvall; Efthymios Kantarelis; Jukka Konttinen; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; gasification; alkali release; kinetic modelling; char reactivity; pore structure; alkalis effects; förgasning; frigörande av alkalier; kinetisk modellering; kolreaktivitet; porstruktur; alkalieffekter; Chemical Engineering; Kemiteknik;

   Sammanfattning : Renewable energy sources are indispensable to meet the rising demand of energy usage  while  reducing  the  negative  environmental  impact  of utilising fossil  fuels. Gasification  is  an  efficient  technology  to  convert  biogenic waste  into  valuable gaseous products. LÄS MER