Abstract
In this paper a practical test of an innovative on-line tar measuring system has been carried out using the reference standard for tar sampling (UNI CEN/TS 15439) and off-line analysis approach. Samples of common reed -collected in Inner Mongolia (China) -have been characterized by means of physical-chemical and thermal analysis. Several experimental tests have been performed in a bench scale pyrolysis apparatus (Free University of Bolzano, Italy) setting different process temperature (300-700°C) and a heating rate of 50°C/min. In each test the condensable fraction (i.e., tar) has been collected and analysed. These analyses have been supplemented with an innovative on-line tar measuring methodology, developed at the Graz University of Technology (Austria). The system consists of a lab scale fluidised bed gasifier coupled with an optical measurement cell. In the measurement cell a UV light stream is produced by means of LEDs having different wavelengths (265nm, 285nm, 300nm and 365nm). The spectrum of absorbed light from the tar in the gaseous products can be detected through a photodiode, being proportional to their concentration. The integration between different analytical approaches on tar characterization has been useful to assess their capability and their potential application.