ผลของเถ้าลอยจากกระบวนการรีดักชันโดยใช้ตัวเร่งปฏิกิริยาต่อสมบัติของปอร์ตแลนด์ซีเมนต์เพสต์และจีโอพอลิเมอร์เพสต์

Abstract

Power generation nowadays is still based on Coal power plants which come up with some pollutions such as the oxides of Sulphur, Nitrogen, or small particle matters. Therefore, specific treatment processes are installed to eliminate or reduce the amount of those harmful toxins. One of the important treatment processes for the coal-fired power plant is Nitrogen oxide (NOx) treatment. Mae Moh Power Plant, the largest coal-fired power plant in Thailand, is currently using a typical NOx treatment system called the "Low NOx burning system". However, for the establishment of new power generators Units 4-7, a new NOx treatment system has been used and known as the "Selective Catalytic Reduction system (SCR)". More efficiency on NOx control for. SCR technologies is achieved by injecting, aqua ammonia (NHx(aq)) or another reductant (NHx(g)) into a furnace or flue gas to convert NOx to N2. Nevertheless, From the process of ammonia injection, there is a chance of unreacted ammonia escaping from the flue gas, yielding ammonia-contaminated fly ash called "'SCR- fly ash". The main objectives of this study are to investigate the characteristics of the SCR-fly ash in comparison with typical high calcium fly ash (H.Ca.) and to evaluate the properties of both OPC-fly ash blended and geopolymer cement pastes using those two types of fly ash. The results showed that the amount of ammonium contamination in SCR-fly ash was dramatically reduced in the first 20 to 30 days after production, and continuously reduce by the passing time. At the testing age of 200 days, it was found that there were no significant differences in the OPC-fly ash blended mixture. But, however, the compressive strength of SCR-fly ash-based geopolymer paste was significantly decreased due to the adverse effects between ammonia residue and alkaline activator in the system. Apart from that, there is no improvement in the mechanical properties of the geopolymer paste with additional nano-silica as an admixture in this study.