COMPUTATIONALLY PREDICTED PERFORMANCE OF PULVERISED COAL FIRED BOILERS AND STUDY OF ASH DEPOSITION PHENOMENON

Understanding of pulverised coal combustion performance including ash behaviour is very important to design optimum boiler furnaces. In the last decades, remarkable advance of computers and computational fluid dynamics (CFD) codes have been realised and plenty of numerical modelling has been applied. However total performance of pulverised coal fired boilers including burner geometries and ash deposition behaviours is still difficult to predict. There are the limitation of computer performance and unknown phenomenon of ash deposition. Therefore, the new method of modelling to perform the full size furnace simulation has been developed to materialise both reduction of calculation load and improvement in prediction accuracy. It is confirmed that this new technique can express the difference between varied burner conditions. Detailed coal ash deposition behaviours and heat absorption rate are currently unknown and were measured and analysed experimentally by using the horizontal cylindrical furnace with water cooled probes. The experiments gave the better understandings of ash deposition and inhibition of heat absorption and heat absorption model is proposed. Boiler furnace heat absorption with ash deposition will be calculated and ash deposition behaviour will be modelled.