Single-particle combustion of Beulah lignite char

A novel single-particle flameless reactor has been designed and constructed for investigating the combustion behavior of individual coal particles, incorporating a three-color optical pyrometer for measuring single-particle temperatures. Results for the combustion of Beulah (North Dakota) lignite char at sizes below 200 ..mu..m and at gas temperatures between 760 and 1040K are presented. It was found that the particle temperature in all cases studied exceeded the local gas temperature by several hundred degrees. The burning rates were controlled by the mass diffusion of oxygen and mean particle temperatures and were found to be linearly dependent on oxygen mole fraction in the gas phase over the range of 0.05 to 0.16. The effects of particle size and oxygen concentration on particle temperature together with preliminary rate data are discussed. 20 refs., 6 figs., 2 tabs.