|Analysis of the moisture re-adsorption of dried Victorian brown coals|
|Because of Victorian brown coal’s strong hydroscopic potential, fully dried coal will very quickly re-adsorb moisture if left exposed to the atmosphere; however the impact of the drying method on the re-adsorption potential has not been examined. This is important because of the possibility of delays in combustion of the fuel. |
Any moisture which re-adsorbs will lower efficiency once it is combusted, so understanding the impact of drying methods may allow better control of the drying conditions.
|Determination of the drying kinetics of Victorian brown coal with steam and hot gas as drying mediums|
|While drying kinetics have already been investigated through different drying technologies, coals and conditions, relatively little information is publicly available regarding using steam as a fluidising medium in conjunction with Victorian brown coal. |
The influence of system parameters on the drying of coal is well-established; however, the relative change in drying ratios between similar properties at different fluidisation mediums has yet to be discussed. Using a laboratory scale fluidised bed, these aspects have been investigated and can be found in Figure 2 and Stokie et al. (2013).
|Figure 2: Typical steam fluidised bed drying kinetic data|
|Development of a drying model to predict drying rate in fluidised beds|
|While fluidised bed models of coal drying do exist, there are still gaps in current methods of calculation. We are working to develop a model that can capture the underlying kinetics and attrition of the dried coals, while being easy enough for engineering use. |
|Once validated, the model will be expanded to include a particle set sized system instead of a single averaged particle diameter. Finally, the attrition results will be incorporated into the existing model, to increase the accuracy of the drying model.|
This project is currently well advanced, and has enjoyed collaboration with international universities including the University of Science and Technology, Liaoning.
|For further information on current work please feel free to contact Professor Sankar Bhattacharya (firstname.lastname@example.org), David Stokie (email@example.com) or consult any recent publications:|
- D. Stokie, J. Yu, A. Auxilio, S. Bhattacharya, Coal Drying and Dewatering for power generation – Current Status, Research and Development Needs, International Conference on Coal Science and Technology, International Conference on Coal Science & Technology Oviedo, Spain 2011
- D. Stokie, M.W. Woo, S. Bhattacharya, Comparison of Superheated Steam and Air Fluidized-Bed Drying Characteristics of Victorian Brown Coals, Energy & Fuels, 27 (2013) 6598-6606
- M.W. Woo, D. Stokie, W.L. Choo, S. Bhattacharya, Master curve behaviour in superheated steam drying of small porous particles, Applied Thermal Engineering, 52 (2013) 460-46
- D. Stokie, S. Bhattacharya, J. Tanner, Physical and Chemical Properties of Steam Fluidized Bed Dried Coal, The 38th International Technical Conference on Clean Coal & Fuel Systems Clearwater, Florida, USA, 2013, pp. 11
- Tahmasebi, Arash; Yu, Jianglong; Han, Yanna; Yin, Fengkui; Bhattacharya, Sankar; Stokie, David, Study of Chemical Structure Changes of Chinese Lignite upon Drying in Superheated Steam, Microwave and Hot Air, Energy & Fuels,
- D. Stokie, M.W. Woo, S. Bhattacharya, Attrition of Victorian Brown Coal in a Fluidized Bed Drier, In Submission.
|For more information on this research, go to the previous page of this e-newsletter.|