Wolf, C.; Stephan, A.; Fendt, S.; Spliethoff, H.; Aho, M.; Leino, T.; Yrjas, P.; Hedman, M.; Kilgallon, P.; Waldmann, B.; Paneru, M.; Galetti, C.; Masci, S.; Ott, D.
Online corrosion monitoring for the combined combustion of coal and chlorine-rich biomasses in pulverised fuel and circulating fluidised bed systems
Second Annual Report 2016
The OnCord project deals with the development of online corrosion sensors in pulverised (PF) and circulating fluidised bed (CFB) combustion systems in order to use high shares of critical low-grade fuels with coal. During the experiments in the small/mid-scale in both firing systems the online corrosion sensors reacted very fast to changes in the flue gas atmosphere. Especially a higher share of vaporized alkali salts in the flue gas affected the derived corrosion signals. Critical shares of biomass in the fuel blend without occurring corrosion could be identified. Main parameters influencing the share of vaporized alkali salts are the ash content and the Al-content/S-content in the coals as well as the K and Cl-content in the biomass. Al-Silicates are capable of capturing the alkali from alkali salts (NaCl/KCl) releasing Cl as HCl. The role of sulphation of alkali salts is currently evaluated. Both online corrosion sensors showed a robust behaviour during the power plant measurements. Due to low shares of co-fired low-grade materials (< 10% e.b.) low corrosion was detected, which is in line with results from small/mid-scale tests. Modelling activities supported the results from experiments, especially chemical equilibrium calculations proved to be very valuable when describing different occurring phenomena. Several journal publications are currently prepared. Additionally the main results will be presented to a wider audience in a workshop planned for the 29.3.17 at the Technical University of Munich.
European Commission Research Programme of the Research Fund for Coal and Steel