1. The quantify of widely used chemicals in an exhaust gas is also limited. Corona-discharge treatment of an exhaust gas containing methanol Masaomi Kikuchi 1, Kohki Satoh 1,2 and Hidenori Itoh 1 1 Department of Electrical and Electronic Engineering, Muroran Institute of Technology, Muroran, Hokkaido 050-8585, Japan 2 Center of Environmental Science and Disaster Mitigation for Advanced Research, Muroran Institute of Technology, Muroran, Hokkaido 050-8585, Japan E-mail: s1424204@mmm.muroran-it.ac.jp 2. EXPERIMENTAL APPARATUS 2. EXPERIMENTAL APPARATUS 1. INTRODUCTION Thermal plasma Electron beam Thermal oxidation (Combusion) Adsorption Discharge plasma Catalytic oxidation Effective area of gas-cleaning methods [2]. 3. RESULTS AND DISCUSSION 3. RESULTS AND DISCUSSION (3) Concentration variations of methanol and ozone （ methanol concentration ： 300ppm ） (3) Concentration variations of methanol and ozone （ methanol concentration ： 300ppm ） REFERENCE REFERENCE  The variations in the discharge current as a function of the applied voltage is marginally affected by the methanol concentration.  The methanol decomposition rates are dependent of initial methanol concentration.  Methanol decomposition rates are independent of the methanol concentration and gas-flow rate when the methanol decomposition rates are plotted against the operation energy density.  Decomposition of methanol are independent of the ozone. 4. CONCLUSION 4. CONCLUSION (1) The influence of the background gas （ methanol concentration ： 300ppm ） (1) The influence of the background gas （ methanol concentration ： 300ppm ） Estimate for operation energy density Estimate for operation energy density Methanol decomposition rates  Discharge chamber : an acrylic cylinder 80mm inner diameter and 210mm length  Applied voltage A positive high DC voltage is applied to the multi-needle electrode to generate a streamer corona discharge between the electrodes.  Initial concentration of methanol : 120ppm, 300ppm and 500ppm  Background gas Mixture rates are N 2 : O 2 = 80 : 20, 95 : 5 and 99.5 : 0.5 and 80 : 20  Concentration measurements of methanol & gaseous products : Infrared absorption spectroscopy The concentration deduced from the absorbance spectra measured by a Fourier Transform Infrared Spectrophotometer (Shimadzu, FTIR-8900) with a gas cell (Infrared Analysis Inc., 10PA), which optical path length is 10m.  Measurement of voltage & current The applied voltage and the discharge current are measured by digital storage oscilloscope (YOKOGAWA Co., Ltd., DL1620).  Electrode : Multi needle to plate electrode The multi-needle electrode consists of needle-clusters, each of which has 26 (13×2) stainless-steel needles (1.5mm diameter and 16.3mm length). Five needle-clusters are arranged with 14.5mm gap on a brass plate with the dimension of 55mm×150mm×3mm (thick). The plate electrode, made of brass with the dimension of 55mm×150mm×2mm (thick) is earthed.  Ozone concentration increases with the input power.  Methanol concentration decreases when the input power increases.  Decomposition of methanol has no dependency on the ozone concentration. operation energy density [4] [W/ppm/slm] = input power initial methanol concentration [ppm] × flow rate [slm]  The variations of decomposition rate show similar tendency.  The methanol decomposition rates as a function of the operation energy density are independent of the methanol concentration and gas-flow rate.  The methanol concentration marginally affects on the corona discharge characteristics.  The methanol decomposition rates are dependent of the methanol concentration.  The variation in methanol decomposition rates are independent of the oxygen concentration.  We developed the gas-cleaning reactor using streamer corona discharge, stabilized by using clustered multi-needle to plate electrode configuration, and decomposed methanol contained in artificial air (nitrogen-oxygen mixture).  We investigated the decomposition characteristics of methanol in the corona discharge The development of discharge-plasma gas-cleaning methods is expected to be an effective method for cleaning the exhaust gas containing low concentration of VOCs.  Discharge current for N2:O2=99.5:0.5 increases rapidly with the applied voltage. Objective (2) The influence of the methanol concentration （ N 2 :O 2 =80:20 ） (2) The influence of the methanol concentration （ N 2 :O 2 =80:20 ） Background Active species that have high oxidation potential, such as OH, O, O3 etc., are produced in a discharge plasma. The species can be used for the treatment of gases contaminated by hazardous substances like volatile organic compounds (VOCs). Further low-concentration of VOCs can be decomposed by discharge plasma treatment. Plasma gas-cleaning has attracted the interest of many researches. The recent alternation of the regulation concerning gas emission [3]. methanol, acetone, etc. Decomposition characteristics of methanol in corona discharge in a background gases of nitrogen-oxygen mixture. [1] K. Urashima, J. S. Chang : IEEE Trans. Dielec. Elec. Insula. 7 (2000) 602 [2] J S Chang : OYO BUTURI ， Vol.69 No.03 (2000) 268 [3] Government Amends Laws, Latest Amendment by Law, No.56 of 2004 (Ministry of the environment) [4] N. Goto et al.: IEEJ Trans., 123-A (2003) 900 V – I characteristics To investigate decomposition characteristics of methanol by streamer corona discharge.