Characteristics of plasma-assisted hydrocarbon SCR system

A plasma-assisted hydrocarbon selective catalytic reduction (HC-SCR) system was constructed and its de-NOx performance was evaluated. An onboard plasma reformer supplied the reducing agent in the system. The reformate gas composition can be varied or the H2/HC ratio can be controlled by controlling the operating conditions. This ratio is important in the SCR process since the performance of the SCR catalyst is dependent on the composition of the reducing agents. Two catalysts were prepared for the test: those having lower-temperature and higher-temperature windows of operation. The proposed system showed a much enhanced de-NOx performance. Onboard plasma reforming enabled achievement of an enhanced de-NOx performance using about half the typical catalyst volume. Fuel penalty of the system remained at ∼3%, with a possibility of further reduction without severe performance degradation. The system volume and power consumption also satisfy conditions necessary for its commercial application. Therefore, it appears suitable for commercial application.

► Evaluation on the engine bench test of plasma assisted HC SCR system was carried.
► Plasma reformer produced controlled composition of hydrogen and hydrocarbon species.
► Even in high S/V of 85,000/hr, plasma reformer resulted in much enhanced de-NOx rate.
► De-NOx rate, start-up time and aging test was done for the on board plasma reformer.
► All the results showed that the plasma HC SCR system is prominent de-NOx solutions.