Examination of Conversion of C3H8 into C3H6 by Electric Discharge Plasma Treatment for Lean-Burn Engines

The conversion of fuel into C₂H₄ and C₃H₆ by an electric discharge plasma treatment is studied in this work. C₂H₄ and C₃H₆ are used as an active species for NOx reduction in an automobile catalyst. They are also useful in the electric discharge plasma reactor of lean-burn engines as plasma assist gas. We suggest a discharge plasma converter (DPC) on the previous catalyst or the second discharge plasma reactor. DPC works as a plasma assist gas converter. Plasma assist gas is generated with discharge plasma treatment at high temperature from fuel or an ingredient of exhaust gas. Diesel fuel, gasoline (C₅H₁₂) or Liquefied petroleum gas (C₃H₈) are enable to use as the fuel. The ingredient of exhaust gas includes C₅H₁₂ in the case of gasoline lean-burn engines. DPC consists of a needle electrode and a metal tube. Electric discharge plasma is generated between the needle and the inner wall of the metal tube. The conversion of C₃H₈ and C₅H₁₂ as volatile reagents has been investigated. C₃H₈ or C₅H₁₂ was diluted by air consisting of 90% nitrogen, 10% oxygen, and approximately 10,000 ppm water; C₃H₈ and C₅H₁₂ were 350 and 210 ppm, respectively. Discharge plasma was generated in the DPC and maintained at 600°C. C₃H₈ was oxidized by the discharge plasma and converted into C₃H₆ and C₂H₄. The concentration of products (C₂H₄ and C₃H₆) was 143 ppm with specific energy density 5J/L. The ratio of products/reagent was 40%. Without discharge plasma the concentration of these products was 101 ppm. In the case of C₅H₁₂ the concentration of these products was 65 ppm with 5J/L. The ratio of products/reagent was 31%. The concentration of these products was 56 ppm without discharge plasma.