What effect does limestone have when added to a fluidized bed boiler?

When limestone is added to a fluidized bed boiler, it acts as a de-sulphuring agent. The primary function of limestone in this context is to capture sulfur dioxide (SO2) produced during the combustion of fossil fuels. As the limestone is heated, it undergoes a thermal decomposition process that releases carbon dioxide (CO2) and produces calcium oxide (CaO). When the calcium oxide reacts with sulfur dioxide, it forms calcium sulfite, effectively removing the sulfur from the flue gases.

This reaction is particularly beneficial for reducing sulfur emissions, which can contribute to acid rain and other environmental issues. By utilizing limestone, fluidized bed boilers can achieve a higher level of emissions control and improve their overall environmental performance. Thus, this choice reflects the important role of limestone in enhancing the efficiency and ecological impact of combustion processes in these types of boilers.