1713 † To whom correspondence should be addressed. E-mail: ynchun@chosun.ac.kr Korean J. Chem. Eng., 28(8), 1713-1720 (2011) DOI: 10.1007/s11814-011-0162-x INVITED REVIEW PAPER Destruction of anthracene using a gliding arc plasma reformer Young Nam Chun* ,† , Seong Cheon Kim*, and Kunio Yoshikawa** *BK21 Team for Hydrogen Production · Department of Environmental Engineering, Chosun University, 375 Seoseok-dong, Dong-gu, Gwangju 501-759, Korea *Frontier Research Center, Tokyo Institute of Technology G5-8, 4259 Nagatsuta, Midori-ku, Yokohama 226-8502, Japan (Received 5 February 2011  accepted 21 June 2011) Abstract−The gasification technology for biomass conversion has a limitation for some applications, including engines and turbines, because it produces tar-containing gas. In this study, a gliding arc plasma reformer was developed to remove tar. The plasma discharge in the gliding-type reformer is based on the both non-equilibrium and equilibrium plasmas. A simulation test was conducted using anthracene, which is produced during the gasification of biomass and waste, as the representative tar substance. In the optimal condition, the anthracene decomposition efficiency was 96.1%, and the energy efficiency was 1.14 g/kWh. The higher heating value of the gas produced from the anthracene decomposition was 11,324 kJ/Nm 3 , and the carbon balance was 98%. The steam flow rate, power input, total gas flow rate, and input concentration change were used as variables for the test. The anthracene decomposition efficiency was 81% when the gliding arc plasma reformer was used. When steam was fed at a rate of 0.63 L/min, the decomposition efficiency was highest (96.1%) due to the creation of OH radicals. The energy efficiency was highest (2.63 g/kWh) when the total gas flow rate was 24.1 L/min. H 2 , CO, and CO 2 were produced as reformed gases. At the steam injection rate of 0.37 L/ min or more, carbon black did not appear. Thus, it was verified that the gliding arc plasma reformer is effective for tar reduction. Key words: Tar Decomposition, Gliding Arc Plasma, Anthracene, Reformer, Gasification INTRODUCTION The demand for oil is skyrocketing along with its price, and the sense of crisis due to the exhaustion of fossil fuels, environmental pollution, and global warming is growing and has led to the enforce- ment of the Kyoto Protocol. Accordingly, many studies on diverse new and renewable energy sources are being conducted. However, energy sources like solar energy, wind power, etc., have limitations in terms of their inherent limits and energy efficiency. Therefore, it is essential to convert biomass and waste resources into renewable energy sources. In this regard, the gasification technology is draw- ing attention because it is the thermochemical conversion method for biomass and waste resources [1-3]. The gasification technology is being used to convert biomass and waste resources into syn- thetic gas, which has diverse applications, such as in gas turbines, engines, fuel cells, and methanol production [4]. Steam gasification, however, generates tar, which is a mixture of compounds contain- ing polyaromatic hydrocarbons and oxygenates. Condensed at a low temperature, tar causes clogging and corrosion in the pipeline during gasification, and also leads to operation trouble and damage to equipment during the following process, as in gas turbines and engines [3-5]. Accordingly, many studies are under way to remove the tar produced during gasification. The method of thermal cracking [6,7] or catalytic cracking [8- 10] is being studied by many researchers as part of the tar removal technology. For thermal cracking, however, high temperature and sufficient retention time are required. In catalyst tar cracking, the catalysts are sensitive to contaminants such as sulfur, chlorine, and nitrogen compounds, generating in gasification of biomass. Other than these methods, plasma is also used to remove tar. A number of studies on plasma discharge types, oxidizer types (air, oxygen, etc.), and tar ingredients have been conducted [11,12] as well as studies on the use of adsorption and the wet-type scrubber for tar removal [13-15]. The gliding arc plasma used in this study is advantageous in that it is compact and starts and responds quickly, it can use diverse fuels and biogases containing hydrocarbon polymer for the tar content, and it can ensure optimal operation with a high conversion rate [16]. The gliding arc plasma discharge can be divided in following three phases as shown Fig. 1; (A) reagent gas break-down, (B) equilib- rium heating phase, (C) non-equilibrium reaction phase [17]. The initial break-down (A) of the processed gas begins the cycle of the gliding arc evolution. The high voltage generator provides the nec- essary electric field to break down the gas between the electrodes, and the discharge starts at the shortest distance between the two elec- trodes. The equilibrium stage (B) takes place after formation of a stable plasma channel. The gas flow convects the resulting small equilibrium plasma volume with a velocity of about 10 m/s, and the length of the arc column increases together with the voltage. The non-equilibrium stage (C) begins when the length of the gliding arc exceeds its critical value. Heat losses from the plasma column begin to exceed the energy supplied by the source, and it is not possible to sustain the plasma in the state of thermodynamic equilibrium. After the decay of the non-equilibrium discharge, there is new break- down at the shortest distance between electrodes and the cycle re-