Selective catalytic reduction of NOx by diesel fuel: Plasma-assisted HC/SCR system

A new NOx reduction system has been developed which can reduce NOx emissions in diesel engine exhaust using oxygenated hydrocarbons (OHCs) generated from diesel fuel reforming as the primary reductants. The system consists of a sidestream hyperplasma reactor, a diesel fuel reformer and a dual-bed catalytic reactor. A unique feature of this system is a diesel fuel reformer that can produce highly reactive OHCs for NOx reduction. Steady-state performance as well as simulated FTP performance of this system for NOx reduction was evaluated in a sidestream connected to the main exhaust stream of a 4.9L, 6-cylinder Isuzu diesel engine dynamometer system. A dual-bed (BaY + CuY) catalyst yielded a mode-average FTP NOx conversion of 61% when the catalyst volume was 3.6 times the engine displacement. NOx reduction efficiency of the reformed diesel fuel was compared with that of an ethanol–dodecane mixture, E-diesel and NH3 in laboratory microreactor experiments and engine dynamometer tests.

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► A plasma-assisted HC/SCR deNOx system was developed.
► Oxygenated hydrocarbons (OHCs) were produced from diesel fuel by air plasma.
► The beneficial effect of plasma is most pronounced at low temperatures.
► The system achieved a mode-average NOx conversion of ∼60% in engine dyno tests.
► The optimized deNOx performance of the system is comparable to that of NH3/SCR.