Exhaust gas flow cleaning method for use in cement clinker producing system in cement industry, involves spraying nitrogenous reducing agent downstream in exhaust gas flow, before exhaust gas flow reaches catalyzer

摘要

The method involves passing exhaust gas flow (6) through a heat exchanger (12). Nitrogenous reducing agent e.g. ammonia and urea, is provided in the heat exchanger for removing nitrogen oxide from the exhaust gas flow by performing selective non catalytic reduction (SNCR) reaction. The nitrogenous reducing agent is sprayed downstream in the exhaust gas flow by performing selective catalytic reduction (SCR) reaction, before the exhaust gas flow reaches a catalyzer (14). Fuel is provided into an auxiliary firing equipment arranged upstream of the heat exchanger. An independent claim is also included for a system for cleaning exhaust gas flow.