Procedia Engineering 56 (2013) 375 – 380 1877-7058 © 2013 The Authors. Published by Elsevier Ltd. Selection and peer review under responsibility of the Bangladesh Society of Mechanical Engineers doi:10.1016/j.proeng.2013.03.135 5 th BSME International Conference on Thermal Engineering Numerical modelling of oxy-fuel combustion in a full-scale tangentially- fired pulverised coal boiler Audai Hussein Al-Abbas a,b , Jamal Naser a , David Dodds a , and Aaron Blicblau a a Faculty of Engineering & Industrial Sciences, Swinburne University of Technology, Hawthorn 3122, AUSTRALIA b Technical College of Al-Musaib , Foundation of Technical Education, Babylon, IRAQ Abstract This paper presents a computational fluid dynamics (CFD) modelling study to investigate Victorian brown coal combustion in a 550 MW utility boiler under the air-fired (standard) and three oxy-fuel-fired cases. The standard case was modelled based on the real operating conditions of Loy Yang A power plant located in the state of Victoria, Australia. A level of confidence of the present CFD model was achieved validating four parameters of the standard combustion case, as well as the previous preliminary CFD studies which were conducted on a lab-scale (100 kW) unit firing lignite and propane under oxy-fuel-fired scenarios. The oxy-fuel combustion cases are known as OF25 (25vol. % O 2 concentration), OF27 (27vol. % O 2 concentration), and OF29 (29vol. % O 2 concentration). The predictions of OF29 combustion case were considerably similar to the standard firing results in terms of gas temperature levels and radiative heat transfer compared with OF25 and OF27 combustion scenarios. This similarity was because of increasing the residence time of pulverised coal (PC) in the combustion zone and O 2 concentration in feed oxidizer gases. Furthermore, a significant increase in the CO 2 concentrations and a noticeable decrease in the nitric oxides (NO x ) formation were noted under all oxy-fuel combustion conditions. This numerical study of oxy-fuel combustion in a full-scale tangentially-fired PC boiler is important prior to its execution in real-life power plants. © 2012 The authors, Published by Elsevier Ltd. Selection and/or peer-review under responsibility of the Bangladesh Society of Mechanical Engineers Keywords: Oxy-fuel combustion;Victorian brown coal; Combustion chemistry; CO2 capture; NOx emission; CFD. 1. Introduction In general, approximately 85% of electricity production is obtained from solid fuel (coal) in Australia. In the Latrobe valley/Victoria, the Loy Yang power plant has been designed to use brown coal. This source of energy is a major contribution to the greenhouse gases (GHG) emissions. In order to keep a continuous usage of existing power plants and make them environmentally friendly, innovations and research on the brown coal combustion in tangentially-fired furnaces can play an important role to develop this economical energy source. In addition, with increasing concerns from the Kyoto Protocol against the global climate change, developments and research on the brown coal combustion can also make it meet a better sustainable progress for power plants (Chun-Zhu, 2004). Recently, several advanced combustion technologies have been developed such as Pre-combustion capture, post- combustion capture, and oxy-fuel combustion capture. These technologies are being considered as the most efficient utilization technologies to reduce CO 2 , NO x , and SO x emissions and fuel consumption (Wall et al., 2009; Kakaras et al., 2007). However, oxy-fuel (O 2 /CO 2 ) combustion technology has been widely considered the most viable technique in the PC power plants. The basic concept of the O 2 /CO 2 technology is to use pure oxygen (approximately 95vol.% O 2 ), produced in air separation units, instead of air (O 2 /N 2 ) in conventional combustion to burn fuel. Due to this high purity of O 2 , a very high combustion temperature is achieved in the combustion zone. This elevated temperature can be diluted by recycling part of the flue gas (about 60-80%) to the furnace so as to decrease the radiation heat transfer to the furnace wall. At the end of this Available online at www.sciencedirect.com © 2013 The Authors. Published by Elsevier Ltd. Selection and peer review under responsibility of the Bangladesh Society of Mechanical Engineers