Long term monitoring of a SCR system in a research biogas plant
Bioenergy from biogas plants results from combustion processes. When these bioenergy carrier are burned in an idle way, all combustible hydrocarbon-containing components are completely oxidized to CO2 and H2O. However, combustion processes under real conditions like in biogas CHP units always release unburned or partially oxidized substances. Due to the target conflict concerning the settings of the engine either CO or NOx can be removed from the exhaust gas. The tightened limit values for pollutant emissions in the 44. BImSchV make the use of an oxidation and/or SCR catalyst necessary. The catalytic performance of a SCR catalyst in a CHP unit (Fa. Schnell, ES0756 (SISU), 75 kWel) of a research biogas plant was monitored over 17 months. In this time 3 measurements were done with a mobile FTIR. The first one was carried out immediately after installation. In addition to the automated ad blue dosing two different higher dosing values were set for 10 min. After 5.5 months the exhaust gas composition was measured again before and after the catalyst. The last measurement was done after 17 months with different target concentrations for NOx in the system. In between the last two measurements ad blue dosing for about 9 months was not undertaken but the catalyst kept installed without interruption. In each measurement the concentration of different exhaust gas components was detected before and after the catalyst in the exhaust gas pipe. Additional to the SCR catalyst an oxidation catalyst coating was included. All parameters monitored by the FTIR flue gas measurement system are listed in this data publication.