Transport Phonemona and Reaction Kinetics of Limestone Powders in Circulating Fluidized Bed Combustor

  • Kuo, Hsiu-Po (PI)

Project: National Science and Technology CouncilNational Science and Technology Council Academic Grants

Project Details

Abstract

The demanding of the energy is increasing, but the supply of the low-sulfur fossil fuels is decreasing. When high-sulfur fossil fuel oxides, sulfur dioxide is formed and causes environmental problems. In industry, limestone rich in calcium carbonate is usually used for in-situ desulfation. Calcium carbonate reacts with high temperature gaseous sulfur dioxide and oxygen to form calcium sulfate or calcium sulfite. Due to the micro-structure of limestone, uniform, networking, and shrinking-core sulfation models have been reported. The (partially) sulfated powders are removed from the system as the bottom or the fly ashes. When using limestone powders for desulfation in circulating fluidized bed combustor, powder sulfation causes the dynamical changes of the powder composition, density and size. These powder properties affect the particle transport phenomena in the combustor significantly. In this project, we will develop a reliable model to effectively predict the composition, size and density of the limestone powders, together with their flow patterns in a circulating fluidized bed combustor. In this two-year project, both the experimental and theoretical modeling works are to be carried out. In the first year, a circulating fluidized bed combustor system will be constructed. This combustor will allow the calcium carbonate powders to be continuously fed to the system together with the high sulfur content petroleum coke powders. The (partially) sulfated powders are removed as the bottom ashes or fly ashes and the compositions, the sizes and the densities of the removed powders will be measured. In the second year, the sulfation mechanisms are developed by coupling the shrinking-core model, the collisional model and the hydrodynamic fluidizing behavior of the powders. The predicted particle flow patterns and the properties of the removed powders will be experimentally validated.

Project IDs

Project ID:PB10108-2793
External Project ID:NSC101-2221-E182-065
StatusFinished
Effective start/end date01/08/1231/07/13

Keywords

  • limestone
  • sulfation
  • transport phenomena
  • reaction kinetics
  • circulating fluidized bed combustor

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