Developmetnt of New SCR System for Marine Diesel Engine

Abstract

New purification technology of the nitrogen oxide discharged from vessels, such as a small coaster, was developed. A new de-NOx system by the combination of an "adsorbent-selective reduction catalyst" was studied as a method of solving the problem that a former type SCR catalyst does not fully operate on the conditions that the exhaust gas temperature is low (below 300℃). Mn-Zr oxide was effective in removing NO at 100-300℃ by absorption in the solid as nitrate. Nitrogen oxides were first stored in the Mn-Zr oxide below 300℃. Then, the stored NOx was released above 300℃ and reduced by the SCR catalyst in the down-stream. As a result of the purification examination using marine diesel engine exhaust gas, it was found that 80% of NOx discharged in a low-temperature region was removable by this system.