Abstract
The mechanical and thermal expression (MTE) process can be used to remove the moisture from high moisture coal such as lignite by applying the thermal energy and mechanical force. The moisture content of lignite at Yallourn, VIC, Australia is around 60–70%. Two-third of the water from the lignite can be removed at 150°C and 5.1 MPa by this process. In the conventional drying process, moisture is driven off by evaporation when the lignite passes through the mill. This process is inefficient from a thermodynamic point of view, because the latent heat of evaporation has to be supplied from the hot flue gas. This paper presents computational fluid dynamics (CFD) investigation of fluid flow and combustion of conventional lignite and MTE lignite in a tangentially fired full-scale industrial furnace. The idea is to investigate the aerodynamics and combustion effect of using MTE lignite in existing furnaces. The furnace investigated was Yallourn stage-2 in Victoria, Australia. CFD software CFX-4 (User Guide, CFX-4–Solver. AEA Technology. Harwell Laboratory, Oxfordshire, 1997) was used in this investigation. The MTE process is under development and has not been used in the real power station for the commercial production of electricity, hence no experimental data is available for comparison with the numerical predictions. To gain confidence in the MTE lignite simulations, the temperature contours and oxygen concentration at different furnace level of the conventional lignite combustion were validated first against the available experimental data. Then the predicted results of MTE lignite combustion were compared with conventional lignite combustion to assess the possibility of burning MTE lignite in existing tangentially fired furnaces.
Similar content being viewed by others
References
User Guide, CFX-4–Solver (1997) AEA Technology, Harwell Laboratory, Oxfordshire
Favas G, Chaffee AL (2002) Beneficiation of latrobe valley lignite with MTE processing. In: Proceedings of the ninth CRC annual conference, 27–28 June, Monash University, Melbourne, Australia, pp 153–158
Wheeler R, Tiu C (2002) A fundamental study of a continuous mechanical and thermal expression (MTE) process for lignite. In: Proceedings of the Ninth CRC annual conference, 27–28 June, Monash University, Melbourne, pp 149–152
Durie RA (1991) The science of Victorian brown coal, Butterworth–Heinemann Ltd
Badzioch S, Hawksley PGW (1970) Kinetics of thermal decomposition of pulverized coal particles. Indus Eng Chem Process Des Dev 9:521
Ubhayakar SJ, Stickler DB, Rosenburg CWV, Ganon RE (1976) Rapid devolatilization of pulverized coal in hot combustion gases. In: 16th symposium (international) on combustion, The Combustion Institute, p 426
Hart J, Naser J (2000) CFD Model of pyrolysis in a pressurised drop tube furnace. In: Proceedings of the seventh CRC annual conference, 22–23 June, University of Adelaide, Australia, pp 201–206
Yost RS, Creasy DE (1990) Shrinking, swelling and true density of morwell brown coal. Fuel 69:648–650
Gibb J (1985) Combustion of residual char remaining after devolatilization. Lecture at course of pulverized coal combustion. Mechanical Engineering Department, Imperial College, London
Ballantyne TR, Mullinger PJ, Ashman PJ, Smith NL (2002) Combustion of dewatered coal in pulverised fuel furnaces. In: Proceedings of the ninth CRC annual conference, 27–28 June, Monash University, Melbourne, Australia, pp 127–130
Jamaluddin AS (1992) Estimation of kinetic parameters for char oxidation. Fuel 71:311–317
Ballantyne TR, Mullinger PJ, Ashman PJ (2003) Comparison of intrinsic reactivity of MTE and non-MTE lignite chars. In: Proceedings of the tenth CRC annual conference, 12–13 June, Swinburne University of Technology, Melbourne, Australia, pp 249–254
Lockwood FC, Shah NG (1981) A new radiation solution method for incorporation in general combustion prediction procedures. In: Eighteenth symposium (international) on combustion. The Combustion Institute, Pittsburgh, pp 1405–1414
Magel HC, Schnell U, Hein KRG (1996) Modelling of hydrocarbon and nitrogen chemistry in turbulent combustor flows using detailed reaction mechanism. In: 3rd workshop on modelling of chemical reaction systems, Heidelberg
Mann AP, Kent JH (1994) A computational study of heterogeneous char reactions in a full-scale furnace. Combust Flame 99:147–154
Epple B, Schneider R, Schnell U, Hein K (1995) Computerized analysis of low-NOx coal-fired utility boilers. Combust Sci Technol 108:383–401
Hossain M, Naser J (2001) Modelling of coal combustion in full-scale industrial furnace. In: 14th Australasian fluid mechanics conference, 10–14 December, Adelaide University, Adelaide, Australia
McIntosh MJ, Ellul WMJ, Norman JA (1985) Measurements in a burner jet of Yallourn W unit 4 boiler. Research and Development Department, State Electricity Commission of Victoria
Habib MA, Ben-Mansour R, Antar MA (2005) Flow field and thermal characteristics in a model of a tangentially fired furnace under different conditions of burner tripping. Heat Mass Transf 41:909–920
Belosevic S, Sijericic M, Oka S, Tucanovic D (2006) Three-dimensional modeling of utility boiler pulverised coal tangentially fired furnace. Int J Heat Mass Transf 49:3371–3378
Achim D, Naser J, Morsi YS (2009) Numerical investigation of full scale coal combustion model of tangentially fired boiler with the effect of mill ducting. Heat Mass Transf 46:1–13
Ahmed S, Naser J (2002) Simulation of the coal combustion of Yallourn stage-2 furnace. In: Proceedings of the ninth CRC annual conference, 27–28 June, Monash University, Melbourne, Australia, pp 221–225
Huynh S, McIntosh MJ, Huynh D (2003) Process design considerations for MTE plant. In: Proceedings of the tenth CRC annual conference, 12–13 June, Swinburne University of Technology, Melbourne, Australia, pp 31–36
Chaffee AL (2003) Water, water everywhere: a drop to drink? (an overview of MTE supporting research). In: Proceedings of the tenth CRC annual conference, 12–13 June, Swinburne University of Technology, Melbourne, Australia, pp 37–42
Acknowledgments
The authors gratefully acknowledge the financial and other support received for this research from the Cooperative Research Centre (CRC) for Clean Power from Lignite, which is established and supported under the Australian Government’s Cooperative Research Centres program.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Ahmed, S., Naser, J. Numerical investigation to assess the possibility of utilizing a new type of mechanically thermally dewatered (MTE) coal in existing tangentially-fired furnaces. Heat Mass Transfer 47, 457–469 (2011). https://doi.org/10.1007/s00231-010-0707-2
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00231-010-0707-2