INTERNATIONAL FLAME RESEARCH FOUNDATION 1 18 th IFRF Members’ Conference – Flexible and clean fuel conversion to industry Freising, Germany, 1, 2, 3 June 2015 – Paper n. 60 ADAPTIVE KINETIC MODEL FOR COAL DEVOLATILIZATION IN OXY-COAL COMBUSTION CONDITIONS Salvatore Iavarone 1 , Gianluca Caposciutti 2 , Chiara Galletti 2 , Leonardo Tognotti 2 , Francesco Contino 3 , Alessandro Parente 1 , Philip J. Smith 4 1 AERO THERMO MECHANICAL DEPARTMENT, UNIVERSITÉ LIBRE DE BRUXELLES Avenue F. D. Roosevelt 50, B-1050 Bruxelles, Belgium 2 DEPARTMENT OF CIVIL AND INDUSTRIAL ENGINEERING, UNIVERSITY OF PISA Largo L. Lazzarino 2, I-56126 Pisa, Italy 3 DEPARTMENT OF MECHANICAL ENGINEERING, VRIJE UNIVERSITEIT BRUSSELS Boulevard de la Plaine, 2. B-1050 Bruxelles, Belgium 4 INSTITUTE FOR CLEAN AND SECURE ENERGY, UNIVERSITY OF UTAH 155 South 1452 East, UT 84112 Salt Lake City, USA ABSTRACT The oxy-coal combustion is emerging as the most likely low-cost “clean coal” technology for both carbon capture and NOx and SOx emissions reduction. The use of CFD tools is crucial for cost-effective oxy-fuel technologies development and environmental concerns minimization. The coupling of detailed chemistry and CFD simulations is still prohibitive, especially for large-scale plants, because of the high computational effort required. So, the development of simple and reliable kinetic mechanisms is therefore necessary. This work presents a CFD study on coal pyrolysis, regarding implementation, validation and comparison of different devolatilization models, assessing their capacity to predict the total volatile yield, depending on heating rate, temperature and coal type. 1. INTRODUCTION Nowadays, coal remains one of the most important energy sources. Fossil fuels, as coal, are expected to continue supplying much of the energy used worldwide. Petroleum remains the largest energy source but its share of world marketed energy consumption will fall in the future. Among the fossil fuels, coal is the source that shows the most important growth [1]. The larger availability, the broader worldwide distribution, and lower cost, in respect to other fossil fuels, make it a leading energy resource for the power generation in the world, especially during economic crises as the actual one. Moreover, it will remain a major energy resource for the next few decades [2]. Unfortunately, the use of coal is affected by an environmental concern, not only because of its greenhouse impact, correlated to the highest share of the carbon dioxide emissions, but also because of the emission of nitrogen and sulfur oxides and the formation of aerosol particles. For these reasons “clean coal” technologies, reducing the emission of pollutants, are of intense technological interest. The emission of greenhouse gases can be reduced in several ways, e.g. improving the efficiency of the power plant with a combined cycle, using a mixture of fuel and biomass, or through Carbon Capture and Sequestration (CCS). Among the different technologies that can accomplish the CO 2 capture, the oxy-combustion is the most interesting: it is emerging as the most expected low-cost technology solution for both carbon capture and simultaneous reduction of NOx and SOx emissions and the most competitive technology option for retrofitting existing coal-fired power plants [3]. Compared with the conventional coal combustion, in the oxy-coal combustion air is substituted with an O 2 /CO 2 mixture. As a result, numerous gas properties such as density, heat capacity, diffusivity and gas emissivity change, impacting coal reactivity. These changes result in a higher volatile release and char burnout, flame ignition delays, improvement of CO 2 separation process, lower emissions in terms of nitrogen oxides, sulfur oxides and particulate matter [4]. The main disadvantage of the use of an oxy-combustion plant is an overall efficiency loss, due to the presence of an air separation unit (ASU).