An engine exhaust after-treatment system including an exhaust passage including a plurality of legs, with an exhaust control valve being positioned at an inlet of each of the legs that is configured to control an amount of exhaust that enters each leg. A desulfurization treatment component is located within each of the legs. An alkaline reagent tank provides an alkaline reagent to the desulfurization treatment component, and a reagent control valve is disposed between the alkaline reagent tank and the desulfurization treatment component. The reagent control valve is configured to control an amount of alkaline reagent that enters the desulfurization component. A controller may be communication with each of the exhaust control valves and reagent control valves, wherein the controller is configured to control the exhaust control valves independently of the reagent control valves.