On Ash Deposition Rates from Air and Oxy-Combustion of Pulverized Coal, Petroleum Coke, and Biomass

Abstract

This paper presents a synthesis of a large body of experimental data on growth rates of ash deposits from the air and oxy-combustion of multiple pulverized solid fuels, including coal, biomass, and their blends. The experimental data were obtained from 35 tests in a 100 kW (rated) entrained-flow combustor that allowed for self-sustained combustion of solid fuels. Ash deposition rates were measured using a wall-temperature-controlled ash deposition probe. The collected deposits were divided into tightly bound “inside deposits” adjacent to the heat transfer surface and loosely bound “outside deposits” that grow further out. Ash aerosol particle size distributions (psd’s) and size-segregated compositions were obtained through electric mobility, light scattering, and impactor methods. Rates of ash deposition for both inside and outside deposits are presented. Rates of growth of the inside deposit were proportional to the sub-micrometer particle (PM1) concentration in the flue gas but correlated poorly with th...