Combustion and Fouling Characteristics of Two Canadian Lignites

Abstract

The report describes combustion tests with Bienfait lignite from Saskatchewan and Onakawana lignite from James Bay. They were burned in a pilot-scale, pulverized-fired boiler primarily to study combustion performance and fireside fouling tendencies under slag-tap conditions. Flame stability and complete combustion were readily obtained, although satisfactory slag tapping was not achieved with either fuel. Fireside ash deposit samples, representing each fuel, were collected from various parts of the boiler and subjected to exhaustive analyses. The results indicate that, when burning Bienfait lignite, selective deposition of ash constituents takes place, resulting in a eutectic composition downstream of the furnace exit. In the case of Onakawana lignite, selective ash deposition did not occur. Deposit analyses, fusion temperatures, and enrichment ratios are given for both fuels.