An exhaust system for a dual-fuel engine includes an exhaust treatment component in an exhaust passageway. The exhaust treatment component is configured to treat exhaust from the combustion of a second fuel and not from combustion of a first fuel. A thermal enhancement device is in communication with the exhaust passageway and positioned upstream from the exhaust treatment component. A controller activates and deactivates the thermal enhancement device based on switching from the first fuel to the second fuel, wherein the first fuel has a higher sulfur content than the second fuel. The thermal enhancement device increases the temperature of an exhaust to combust a residual amount of the first fuel present in the exhaust passageway during the switch between the first fuel and the second fuel.