電気加熱による尿素SCR触媒の早期活性

抄録

Urea-SCR catalysts for NOx purification exhibit lower purification performance at the low-temperature below 200°C. An electrically heated catalyst (EHC) is one of the effective methods to improve conversion rates.

In this study, reactor tests were carried out using EHC test pieces to compare the deNOx performance of catalyst heating and gas heating. In the former, the catalyst substrate was heated directly, while in the latter, the gas flowing into the catalyst was heated. The results showed that catalyst heating was superior in terms of heating rate until about 50 s after the start of heating, after which gas heating became dominant. Furthermore, the wall temperature inside the catalyst was on average about 13 °C higher with gas heating than with catalyst heating at steady state. Gas heating was superior to catalyst heating in terms of the time it took for the conversion rate to reach steady state and the conversion rate at that point at the same power output. The study concluded that gas heating improves the purification rate more effectively than catalytic heating.