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Show 2. THE EVALUATION OF THE COMBUSTION CHARACTERISTICS OF BIOMASS DERIVED LIQUID FUELS There has been considerable interest in recent years in the pyrolysis of biomass for the production of liquid fuels and chemicals. The liquid produced from the pyrolysis of biomass is composed of a complex mixture of oxygenated hydrocarbons and residual char particulates. The exact composition and char content is dependent on the particular pyrolysis process, of which there are many being developed. These include conventional slow pyrolysis processes to more advanced fast processes such as flash, vacuum and hydro-pyrolysis. The liquid produced is referred to as bio-oil. These bio-oils are perceived to have the advantage of being derived from renewable biomass resources, and thus, do not ultimately ~ontribute to carbon dioxide concentration build-up in the earth's atmosphere when they are burnt. In this investigation, these fuels were considered as potential replacement fuels for application to existing oil fired systems. The amount of information available in the literature on the handling and combustion of bio-oils is extremely limited. Consequently, a research programme was· formulated [2] to address this lack of information. The objective of this programme was to evaluate the combustion and pollutant formation characteristics of two bio-oils derived from slow pyrolysis processes and compare the performance with heavy fuel oil. A secondary requirement was to set up a standard test procedure for non-standard liquid fuels, based on the concept that these fuels would be fired in industrial boilers. This investigation forms part of the European Community biomass research programme and was financially supported through the Joule Programme. The project was also part of the Foundation's facility development programme. The experiments were ·executed on IFRF water cooled furnace no 2. The furnace was modified to simulate the thermal environment of a small industrial boiler or process heater by partial refractory lining of the furnace (see Figure 1). The burner used was a flexible externally air staged burner. 1his burner allowed for low NOx operation and for systematic variations in burner input parameters such as swirl level and combustion air velocities. The burner was designed to operate at a nominal thermal input of 2 MW. The secon~ary and tertiary combustion air were preheated to temperatures .of around 30Q0C. A number of different atomisers were tested in the experiments [3]. As one of |