| Budget Amount *help |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Research Abstract |
Investigation of plasma NOx treatment for diesel exhaust gas at exhaust gas temperature ranges was carried out. Temperature of exhaust gas from diesel engine attains to about 400 deg at full power. Plasma treatment for this high temperature gas will be different from that for lower temperature in its efficiency, because chemical reactions become active at elevated temperature. Exhaust gases from a 2.4kVA diesel engine generator was used as a target of processing, and special experimental system that endures the high temperature was build in laboratory. Direct discharge and ozone injection method were used to investigate the effect of temperature for NO removal efficiency.
In the first year, the NO removal efficiency up to 150 degree was investigated, and it was found that the NO removal efficiency by direct discharge method increases to about 30g/ kWh at the temperature range from 90 degree to 130 degree. It was also found that ozone injection method can be applied to at least up to 180degree, in spite of the suspicion that ozone is destroyed at high temperature and will not work. Hydro-carbon addition to exhaust gas has been known as a method to improve the NO removal efficiency; however there was no significant difference in the effect at high temperature up to 150degree in comparison with lower gas temperature.
In the second year, the experimental system was improved to perform the plasma treatment at much higher temperature by adding some gas heating system. Experiments up to 220 degree were carried out, and it was found that the efficiency increases to 30 to 35 g/ kWh. In order to do experiment at much higher temperature, a new compact experimental system, which uses 1/10 of exhaust gases, was built. The plasma treatment up to 250 degree was become possible, and the experimental results showed that the NO removal efficiency increased up to 60g/kWh at gas temperature of 250 degree.
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