The system for use in a vehicle, comprises a decomposition unit (20) for at least partial decomposition of a compound under catalysis of a biological catalyst. The system is further provided with a storage unit (30) for storage of biological catalyst, and with a dosing device (31) for transferring biological catalyst into the decomposition unit (20).

A method for exhaust gas post treatment is provided, comprising the following steps: a) providing a nitrogen oxide-containing raw exhaust gas, b) introducing the nitrogen oxide-containing raw exhaust gas into a catalytic evaporator (1), c) introducing a fuel into the catalytic evaporator (1), whereby a converted fuel is obtained, d) mixing urea with the converted fuel, and e) feeding the mixture obtained after step d) into an exhaust gas post treatment system (8). Alternatively or in addition, a device may be provided for exhaust gas post treatment.

Provided are embodiments for apparatuses, systems and methods for reducing emissions in an exhaust gas flow of an engine, the apparatus comprising: a reactor vessel positioned externally from the exhaust gas flow, the reactor vessel comprising an inlet and an outlet, the outlet in communication with the exhaust gas flow; an injector positioned within the reactor vessel, the injector receiving a reductant flow from the inlet of the reactor vessel and combining the reductant flow with a pressurized gas flow to generate a reductant spray; and an ammonia generation means within the reactor vessel, the ammonia generation means generating a gaseous reductant flow from the injected reductant flow, the gaseous reductant flow transmitted into the exhaust gas flow via the outlet of the reactor vessel.

An exhaust treatment device includes an injection unit that injects urea water into the exhaust pipe, a first plate that is provided upstream of the injection unit in the exhaust pipe, an arc-shaped second plate that is provided along the axial direction in the exhaust pipe and faces the injection unit, and a third plate that is provided downstream of the second plate in the exhaust pipe, wherein the first plate includes a first inflow hole formed at a position away from a central portion thereof, and a guide portion configured to direct the exhaust gas introduced from the first inflow hole toward the injection portion, and the third plate includes an outflow hole formed in a central portion thereof.