Method and device for providing a gas flow containing a reducing agent

A device for providing a reducing-agent-containing gas flow in the exhaust gas of an internal combustion engine, the device comprising:

• i) at least one duct including at least one first zone configured for at least partial evaporation of at least one reducing agent precursor to form a gas flow in a first stage and at least one second zone configured for at least partial heating of the gas flow in a second stage following said first stage, said at least one duct configured to receive the at least one reducing agent precursor alone in said first zone and to conduct the at least one reducing agent precursor through said first zone and said second zone without mixing with any other substance;
• ii) a transportation device configured for providing the at least one reducing agent precursor as a liquid, a solid or a urea water solution in said at least one duct;
• iii) at least one converter disposed downstream of at least said first zone and configured for converting the reducing agent precursor in the gas flow into at least one reducing agent;
• and
• iv) at least one heater for heating said first zone to a first temperature of 180° C. or lower and for heating said second zone to a second temperature of 250-550° C.;
• said at least one duct and said at least one converter configured to convert the reducing agent precursor to form reducing agent in or after said second stage and in or downstream of said at least one second zone.