SCR deNOx catalyst management and minimizing the total cost of ownership of SCR deNOx installations

摘要

This paper summarizes a case about SCR deNOx catalyst management. It discusses catalyst lifetime extension and reduction of the total cost of ownership of the deNOx installation of the 660MW pulverised coal power station of Gheco One in Thailand. This case clearly shows the importance of O&M aspects on the global deNOx performances, on top of catalyst performances. Multiple non- catalyst improvement projects were implemented, which led to the extension of catalyst lifetime without disturbing the catalyst. This included the optimisation of the combustion where one of the targets was to minimize and to homogenize the primary NOx. We have tuned the ammonium injection to reduce the ammonia slip and as such to extend the catalyst lifetime. The catalyst chosen by the EPC in combination with the limited performances of the cleaning devices was not optimal. Moreover, from 2016 on, the new coal mix induced more plugging of the SCR catalyst. This issue is now taken into consideration with original and future catalyst design and replacements. A new performant deNOx cleaning system was designed in order to prevent further plugging issues in the deNOx reactors. Regular catalyst sampling and analysis allows us to realistically forecast and quantify the remaining catalyst lifetime. It allows for good budgeting and planning of appropriate measures to be taken during operation, or during outages.