Sökning: "Dense bed"

Visar resultat 1 - 5 av 30 avhandlingar innehållade orden Dense bed.

1. 1. Fluid Dynamics of the Bottom Bed of Circulating Fluidized Bed Boilers

   Författare :Anders Svensson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fluidized beds; circulating fluidized bed boilers; fluctuations; fluidization regimes; bottom bed; bed porosity; fluid dynamics; bubbling beds; circulating fluidized beds; non-slugging; bed expansion; particle concentration;

   Sammanfattning : The fluid dynamic conditions in the furnace of a fluidized bed boiler influence the combustion and the production of harmful emissions. A substantial amount of the bed material in a circulating fluidized bed (CFB) boiler is present as a dense bubbling bottom bed. LÄS MER

3. 2. Solids Flow in Large-Scale Circulating Fluidized Bed Furnaces

   Författare :Tove Djerf; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Solids flow; Transport zone; Fluid-dynamical down-scaling; Splash zone; Circulating fluidized bed boilers; Dense bed;

   Sammanfattning : The flow pattern of solids established in large-scale circulating fluidized bed (CFB) furnaces is of great importance for the performance of commercial CFB boilers, as it governs the heat transfer and mixing of the fuel and any other reactive solids. The solids flow pattern in the riser is crucial for the design and scaling up of large-scale CFB technologies for the thermochemical conversion of solids. LÄS MER

4. 3. Fluidized Bed Operating Parameters and Eulerian Erosion Models

   Författare :Mattias Gustavsson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Eulerian erosion model; fluidized bed; distributor plate; slugging; plenum chamber; brittle; two-fluid model; ductile; air-feed system;

   Sammanfattning : A numerical two-fluid code, Gemini 2D, was adapted to study gas-solid fluidization in arbitrary 2D domains. The code was also used to study fluid dynamic mechanisms of dense particle flow that cause ductile and brittle erosion of solids. LÄS MER

5. 4. Solids Flow Pattern in Circulating Fluidized-bed Boilers

   Författare :Andreas Johansson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; scale-up; hydrodynamics; combustion; loop seal; wall-layers; Circulating Fluidized Bed;

   Sammanfattning : The background of this dissertation is the knowledge of circulating fluidized bed (CFB)technology, which has reached a level enabling units of several hundred megawatts ofelectricity to be constructed and employed. Yet an improved understanding of the technologyis needed in order to further develop and optimize large-scale combustion in CFB boilers,especially since the operating conditions and the geometries of large boilers differ from thosetypical for laboratory units, in which most of the research hitherto has been performed. LÄS MER

7. 5. Hydrogen Production by Integration of Fluidized Bed Heat Exchangers in Steam Reforming

   Författare :Viktor Stenberg; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; oxygen carrier aided combustion; chemical-looping combustion; bed-to-tube heat transfer.; steam reforming; fluidized bed heat exchanger;

   Sammanfattning : The possibility to integrate fluidized beds as heat sources for steam reforming in industrial hydrogen production plants is examined in this work. The proposed processes include traditional catalytic steam reforming of natural gas (SMR), shift reactors and purification steps; the main difference is the reformer furnace. LÄS MER