Handling, transport and dispersion of sorbent powder for in-furnace injection. Final report, September 1, 1993--August 31, 1994

The focus of this project is on sorbent injection technologies using dry, calcium-based sorbents for high-sulfur coal flue gas desulfurization. The goal is to provide research findings on handling, transport and dispersion of sorbent powder, aimed at improving SO{sub 2} (to at least 90%) removal and increasing sorbent utilization in a cost-effective fashion. The purpose of this project is to investigate the fundamental aspects of powder technology relevant to the fine sorbent powders, and to provide means of improving sorbent performance through superior dispersion and reduced dispersed particle size. This project is in two phases, Phase 1 ``Powder Characterization`` and Phase 2 ``Powder Mechanical Properties``. Phase 1 involves characterization of the sorbents in terms of their electrostatic properties. The triboelectric charging of powders are studied in detail by measuring sorbent charging as a function of material properties as well as transport conditions. A variety of sorbents are tested, including laboratory-made lignohydrates, calcite, dolomite, dolomitic hydrate and hydrated lime. The effects of transport tube material and gas properties, specifically humidity and velocity on the extent of sorbent charging are also investigated. A population balance model is developed to account for the particle size distribution for powder dispersion through gas-solid injection nozzles. The variations of the transition probability with the booster air velocities is examined. Simulation of particle size distributions under some operating conditions is conducted. Phase 2 investigates the flow properties of several calcium-based sorbents under different handling and transporting conditions. Effect of moisture content, as an important handling condition, on these properties is examined. Determined properties has been analyzed to study their effect on the transport and handling processes