Process for the catalytic cleaning of the exhaust gas from a combustion plant

A process for cleaning exhaust gas from a combustion plant, which comprises:

• providing a combined conversion and mixing duct having a predetermined longitudinal axis;
• obliquely to the predetermined longitudinal axis, introducing exhaust gas into the combined conversion and mixing duct;
• forming an exhaust gas stream through the duct along the predetermined longitudinal axis;
• injecting reducing agent into the exhaust gas stream flowing through the conversion and mixing duct, and mixing the reducing agent with the exhaust gas and simultaneously converting the reducing agent;
• providing a reaction duct parallel to the conversion and mixing duct, and deflecting the exhaust gas stream from the conversion and mixing duct into the reaction duct and causing the exhaust gas to flow in a direction opposite the predetermined longitudinal axis;
• contacting the exhaust gas with a reduction catalyst in the reaction duct and reducing reducible exhaust gas components of the exhaust gas;
• and
• discharging a stream of cleaned exhaust gas from the reaction duct.