Why do circulating fluidized bed boilers use slag cooling devices?

Circulating fluidized bed boiler is the most industrialized clean coal combustion technology. The circulating fluidized bed boiler adopts fluidized combustion, and its main structure includes two parts: the combustion chamber (including dense phase zone and dilute phase zone) and the circulating return furnace (including high-temperature gas-solid separator and return system). The biggest difference from bubbling fluidized bed combustion technology is that the operating wind speed is high, which intensifies heterogeneous reaction processes such as combustion and desulfurization. The boiler capacity can be expanded to a large capacity acceptable to the power industry (600MW or above). Currently, circulating flow Chemicalized bed boilers have well solved basic problems such as thermal science, mechanics, and materials science as well as engineering problems such as expansion, wear, and over-temperature, and have become the ideal choice for refractory solid fuels (such as coal gangue, oil shale, municipal garbage, sludge, and other waste materials). Advanced technology for energy utilization.