Central European Symposium on Plasma Chemistry edition:5 location:Balatonalmádi, Hungary date:25-29 August 2013
Plasma based systems are relatively new players in the field of waste treatment. They are however gaining more and more attention, driven by the ongoing development of a more sustainable waste management practice. The continued advances that are being made in the application of plasma technology for waste treatment increase the acceptance of this technology as a viable alternative to more conventional treatment options. Here, the focus is on two-stage plasma gasification systems where waste gasification is followed by plasma cleaning of the produced synthesis gas (syngas). Syngas can be burned directly in internal combustion engines, used to produce methanol and hydrogen, or converted via the Fischer-Tropsch process into synthetic fuel. A major problem associated with biomass and waste gasification is the production of tar. Tar in the product gas will condense at low temperatures, and lead to clogged filters and blocked engines. There exist a number of treatment options, including mechanical methods (e.g. filters, cyclone), thermal and/or catalytic cracking, and more advanced plasma methods. Several researchers have investigated the applicability of plasma methods for gas cleaning. The studies available in the literature typically focus on VOC removal, mainly by using non thermal plasma. Nair has investigated corona plasma for tar removal. He performed experiments on a tar model compound (naphthalene) to identify the chemical mechanisms for tar removal in syngas. Nair performed experiments up to a temperature of 400°C. However, syngas exits the gasifier at a temperature of at least 750°C. The development and commercialization of plasma systems for syngas cleaning would benefit from more fundamental insights into the behavior of plasma tar cracking mechanisms at higher temperatures. Furthermore, the work performed by Nair can be extended to experiments on different tar model compounds (e.g. pyrene) and on real tar, obtained from waste pyrolysis experiments. A pulsed corona plasma lab setup is used to determine the efficiency of plasma tar cracking for different tar model compounds and varying operating conditions. This paper discusses the experimental results for different tar model compounds at varying temperature.