Search for dissertations about: "fluidized beds"

Showing result 21 - 25 of 61 swedish dissertations containing the words fluidized beds.

2. 21. Macroscopic modeling of fluid dynamics in large-scale circultaing fluidized beds

   Author : David Pallarès; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fuel mixing; fluid dynamics; large-scale circulating fluidized bed; particle tracking;

   Abstract : Satisfactory knowledge of the fluid dynamics governing the gas-solid flow in large-scaleCirculating Fluidized Bed (CFB) units is still lacking, although the CFB technology is widelyused for power (and heat) generation. Due to the complex two-phase flow in large CFB unitsfluid dynamical modeling of practical use is so far limited to a macroscopic approach andavailable models generally focus in describing one of the following key-phenomena: maingas-solid flow pattern, mixing of fuel particles and gas mixing. READ MORE

4. 22. Packed-Fluidized Bed Reactors – Batch Experiments and Fundamental Modeling with Random Metal Packings

   Author : Nasrin Nemati; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Bubbling fluidized bed; Heat transfer; Confined fluidization; Chemical-looping combustion; Mass transfer; Random packing; Packed-fluidized bed;

   Abstract : The aim of this work is to investigate the effect of random packings on heat and mass transfer phenomena, when applied in bubbling fluidized beds. For this purpose, first, the heat transfer coefficient to a horizontal tube submerged in a fluidized bed containing various types of random packings was investigated. READ MORE

5. 23. Heat Transfer in Circulating Fluidized Bed Boilers

   Author : Claes Breitholtz; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; similarity; char; heat transfer; tube wall; circulating fluidized bed; particle; radiation; scaling; particle convection; gas convection;

   Abstract : Heat transfer to single particles in the transport zone of circulating fluidized beds and heat transfer to membrane tube walls have been investigated. The heat transfer coefficient to spheres in the transport zone of a circulating fluidized bed boiler has been measured with dark and light calorimeters. READ MORE

6. 24. Fluidized-Bed Reactor Systems for Chemical-Looping Combustion with Inherent Separation of CO2

   Author : Eva Johansson; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Chemical-Looping Combustion; Interconnected Fluidized Beds; Carbon Dioxide Capture;

   Abstract : In chemical-looping combustion (CLC) a gaseous fuel can be burnt with inherent separation of carbon dioxide. The system consists of two reactors, a fuel reactor and an air reactor and an oxygen-carrier in the form of metal oxide particles that transports oxygen from the air to the fuel. READ MORE

7. 25. Lateral mixing of solids in bubbling fluidized beds – experimental quantification

   Author : Erik Sette; Chalmers tekniska högskola; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; solids cross-flow; lateral dispersion; Solids mixing; fluid-dynamic scaling;

   Abstract : For solid fuels, thermochemical conversion processes such as combustion and gasification are especially suitable to be carried out in fluidized bed units because of the relatively high mixing rates, fuel flexibility and the possibility to use active bed material to enhance process efficiency. Fuels such as biomass and waste, which are commonly used in fluidized beds, are characterized by volatile contents much higher than what is found in fossil fuels such as coal. READ MORE