Reduction of nitrogen oxide emissions from boiler B4 at the Chvaletice Power Plant

This project was delivered by our company as a turnkey solution for the engineering department of the Chvaletice Power Plant. The goal was to reduce NO_x emissions from 260 mg/Nm³ to 190 mg/Nm³ while keeping ammonia slip below 5 mg/Nm³. Due to design constraints, modifications had to be made to the pressure part of the boiler by creating bends to allow for the placement of injection lances in the membrane wall of the boiler. The main challenge encountered during the project was the high temperature in the combustion chamber, which exceeded the optimal range of 970–1050 °C required for proper SNCR technology operation. To address this issue, the injection lances were equipped with a selective cooling level (SCL) system. This system provides localised cooling in the combustion chamber by injecting water just below the urea injection point, ensuring the ideal temperature for NO_x reduction is achieved. Without installing the SCL technology, NO_x reduction would not have reached the required levels, as the urea would not have reacted properly with NO_x emissions at higher temperatures, resulting in the failure to achieve the desired reduction.