British – French Flame Days, Lille 9 / 10 March 2009 Characterisation of Pulverized Coal and Biomass Co-firing on a 3 MW th Combustion Test Facility Using Flame Imaging and Gas/Ash Sampling Techniques – P Molcan, G Lu, T Le Bris, Y Yan, B Taupin, S Caillat 39 Characterisation of Pulverised Coal and Biomass Co- firing on a 3MW th Combustion Test Facility Using Flame Imaging and Gas/Ash Sampling Techniques P. Molcan (1) , G. Lu (2) , T. Le Bris (1) , Y. Yan (2) , B. Taupin (3) , S. Caillat (1) (1) École des Mines de Douai, Département Énergétique Industrielle, 941 rue Charles Bourseul, BP 10838, 59508 Douai, France (2) Department of Electronics, University of Kent, Canterbury, Kent CT2 7NT, UK (3) Veolia Environnement R&D, 291 Avenue Dreyfous Ducas, 78520 Limay, France Experimental investigation into the co-firing of pulverised coal with biomass on a 3MW th Combustion Test Facility has been conducted. A variety of combustion parameters including flame temperature, gas species within the flame and fly ash in flue gas, were measured using flame imaging and gas/ash sampling techniques under a range of co-firing conditions. The results suggest that, due to the varying physical and chemical properties of the biomass, the biomass additions have impact on the combustion characteristics such as increased temperature, improved flame stability and higher level of char burnout. Introduction Co-firing of biomass with coal at existing coal-fired power plant has been widely adopted as one of the main technologies for reducing CO 2 emissions. However, biomass has very different physical and chemical properties from coal. The uncertainty of the fuel properties and co-firing conditions has resulted in a range of combustion problems including flame stability, low thermal efficiency, high levels of unburned carbon and other pollutant emissions, fouling and corrosion of the furnace [1-3]. To achieve efficient operation of co-firing power plant it is vitally important to develop the knowledge and in-depth understanding of the characteristics of co-firing biomass and coal under a wide range of combustion conditions. As part of European Interreg IIIa project- Combustion Optimisation through Advanced Modelling and Measurements, research work on the characterisation of the co-firing biomass and coal has been carried out on a 3MW th Combustion Test Facility (CTF). The characteristic parameters of the combustion are measured using flame imaging and gas/ash sampling techniques. The correlations between the measured parameters and corresponding combustion conditions are investigated. Methodology The temperature of solid particles within the flame (such as coal particles, char, soot etc.) was measured using the flame imaging system developed by the University of Kent [4, 5]. The system, working on the two-colour pyrometry, is capable of providing the two- dimensional temperature distribution of the flame, along with other characteristic parameters including the oscillation frequency, brightness, size and shape of the flame. In this study, the optical probe/camera of the system was installed at a view spot of the furnace sidewall close to the burner (Fig. 1) so whole root of the flame is visualised. The gas phase temperature of the flame zone was also measured using a suction thermocouple probe. There are total of 18 measurement points along the two lines across the flame zone, as shown in Fig. 1. In addition, online analysis of gaseous products was carried out throughout the tests. Concentrations of O 2 , CO, CO 2 , NO and SO 2 were measured within in the flame and in the flue gas based on the diamagnetism (for O 2 ) and the IR absorption method (for CO, CO 2 , NO and SO 2 ). Experimental