Potential benefits of experimental modelling techniques when assessing combustion behaviour of a suite of coals

Since coal will remain a major source of fuel for power generation for the foreseeable future, it is important for users to maximise their efficiency from the currently available markets. Russia is a dominant supplier to the UK at present, and burnout is known to vary considerably, depending on the source. In this study, eight Russian coals in pulverised size (75% less than 75 μm) were characterised using standard techniques, non-traditional image analysis techniques and with a combustion modelling approach (ChB), in order to predict burnout characteristics. These coals were then pyrolysed in a drop tube furnace, at 1300°C, 150 ms and 1% oxygen, and the subsequent chars characterised for reactivity and morphology. The chars were then refired in order to assess burnout propensity at 1300°C, 5 vol.-% oxygen and 600 ms. The results show that the ChB modelling technique can accurately predict burnout performance of unknown coals and may provide a cost effective approach to assess coal combustion performance in pulverised coal fired furnaces, without the need for pilot scale trials, or drop tube furnace tests.