Co-combustion of biocoal and lignite in a circulating fluidised bed combustor to decrease the impact on global warming

Abstract

This work covers co-combustion of biocoal obtained from red pine wood chips with Orhaneli lignite in a 30 kW-thermal capacity circulating fluidised bed combustor (CFBC) system in air and oxygen-enriched atmosphere. The combustor was of 108 mm inside diameter and 6 m height. The combustion temperature was held at 850+50°C. Oxygen enriched combustion tests were carried out at different ratios of lignite and biocoal mixtures. Biocoal share in the fuel mixture was increased up to 50% by wt. It was found that the fuel mixtures up to 50% by wt. of biocoal were combusted effectively in the system. The oxygen concentration in the oxidant was varied between 21 and 27% by vol. for the oxygen-enriched combustion experiments. The results showed that biocoal can be a good additive fuel to lignite coal and oxygen-enriched co-combustion is an option for reducing flue gas emissions of SO2, CO and N2O.