STUDY ON UPGRADED LOW RANK COALS PROPERTIES
DOI:
https://doi.org/10.30556/imj.Vol12.No2.2009.564Keywords:
low rank coal, UBC, upgraded coal propertiesAbstract
Upgraded brown coal (UBC) process has been discussed elsewhere. This process has been developed to produce an upgraded low rank coal with quality similar to a bituminous coal which is acceptable commer- cially and has low moisture content. Three Indonesian low rank coals, Berau, Tabang and Samaranggau coals were upgraded by upgraded brown coal (UBC) process to study the influence of the process on the properties of the upgraded low rank coals by conducting chemical and physical analyses such as proxi- mate, ultimate including calorific value and equilibrium moisture, functional group of C-H and C=O, coal petrography, specific surface area and briquettability.
The result of proximate analysis indicated that the inherent moisture of the upgraded low rank coals de- creased significantly compared with that of the raw coals. Hence, the calorific value of the upgraded coals increased. The ash content of the upgraded coals was not change obviously due to that the UBC process was conducted at low temperature. However, the volatile matter content increased slightly due to the kero- sene or residue that left and pluged over coal pores to prevent the reabsorbtion of moisture. From ultimate analyses, carbon content of the upgraded coals increased, whereas the hydrogen and oxygen contents decreased. The UBC process hardly affected the sulfur and nitrogen contents. The result of equilibrium moisture measurement showed that the moisture content of all upgraded coals were less than 9%. The functional groups of C-H and C=O of the upgraded coals were slightly less than those of the raw coals. The aromaticity of the upgraded coals were increased. The petrography of both the raw and the upgraded coals indicated that the mean vitrinite reflectance was slightly higher in the upgraded coal compared to the raw coal. There was no significant quantity and textural differences of maceral in both coals. The specific surface area of the upgraded coals was lower than that of the raw coal due to the plugging of pore structure and shrinkage by residual oil addition. The upgraded low rank coals briquette according to drop shutter and compressive strength tests indicated good characteristics of briquette.
Based on these results, UBC process only reduces the moisture content, so that the calorific value of the coal increases. Whereas the other parameters are not significantly change. UBC process does not increase the rank of the coal, therefore, it could only be applied to improve the calorific value of low rank coal which has low ash and sulfur contents.
References
Annual Book of ASTM Standards, 2005. Section Five; Copyright ASTM International, 05.06, 100 Barr Harbor Drive, West Conshohocken, USA.
Daulay, B., Salim, A.D., Otaka, Y., Deguchi, T., Makino, E., Rijwan, I., and Umar, D.F., 2003.
Proc of The 4th International Conference and Exhibition on Coal for Power and Economic Development.
Deguchi, T., Shigehisa, T., Makino, E. and Otaka, Y., 2002. Proc. International Conference and Exhibition on Clean and Efficient Coal Tech- nology in Power Generation, Coal-Tech 2002, Indonesia.
Ibara, J. V. and Miranda, J. L., 1996. Vibrational Spectroscopy, 10, 311-318.
Mahidin, T., Ogaki, Y., Usui, H., and Okuma, O., 2003. The Advantages of Vacuum Treatment in The Thermal Upgrading of Low Rank Coals on The Improvement of Dewatering and Devolatilization, Fuel Processing Technology, 84, 147-160.
Ohki, A., Xiao, F.X., Nakajima, T., Itahara, T. and Maeda, S., 1999. Change in Property and Com- bustion Characteristics of an Indonesian Low Rank Coal Due to Hydrothermal Treatment, Coal Preparation, 21, pp. 23-24.
Painter, P., Starsinic, M. and Coleman, M., 1985. in J. R. Ferraro and L. Basile (ed), Fourier Transform Infrared Spectroscopy, Vol. 4, Aca- demic Press, Orlando.
Shigehisa, T., Deguchi, T., Shimasaki, K. and Makino, E., 2000. Proc. International Confer- ence on Fluid and Thermal Energy Conver- sion, Indonesia.
Suwono, A. and Hamdani, 1999. Upgrading The Indonesian’s Low Rank Coal by Superheated Steam Drying with Tar Coating Process and its Application for Preparation of CWM, Coal Preparation, 21, pp. 141-153.
Umar, D.F., Usui, H. and Daulay, B., 2005. Char- acterization of Upgraded Brown Coal, Coal Preparation, 25, 1, pp 31-45.
Umar, D.F., Daulay, B., Rijwan, I., Sodikin, I., 2005. Characterization of Upgraded Brown COAL (UBC) Proc. of Indonesia-Japan Joint Semi- nar on Upgraded Brown Coal (UBC) Technol- ogy, Jakarta.
Downloads
Issue
Section
License
Indonesian Mining Journal provides immediate open access to its content on the principle that making research freely available to the public to supports a greater global exchange of knowledge.
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
