We supplied, installed, and calibrated two SCR systems for generators of 2 MW each for the Dolna Odra power plant.

The required NOx reduction was quite high (more than 90%), so it was necessary to take a close look at the process through numerical simulations. An unquestionable difficulty was the elbow just before the inlet to the mixing pipe and the sheer length of the pipe, as the reactor could not protrude beyond the contour of the container.

A urea dosing system with 4 nozzles and a static mixer with a very low flue gas pressure drop was used. The mixer fulfilled the function of both breaking the urea droplets into smaller ones and swirling the exhaust gas stream to make the mixing process as efficient as possible. High NOx reduction is only possible with homogeneity of NH3 concentration and NOx-containing exhaust gas (>90%).

During the design of the SCR system, simulations were performed on different geometries, i.e. the mixer as well as the position of the metering nozzles, selecting the most optimal ones.
As the SCR system is located outdoors, we used stainless steel welded thermal insulation so that the weather conditions would have the least impact on the life of the unit.

We tested the system according to the ISO standard for generators, at loads of 10,25,50,75 and 100%. After calibration of the system, the requirements for NOx emissions for stationary engines above 1 MW, i.e. 190 mg/Nm3 at 15% O2, were met.