What is the difference between limestone powder, calcium oxide and calcium hydroxide for desulfuriza

What are the effects of using limestone powder, calcium oxide and calcium hydroxide in the desulfurization process in power plants or copper and aluminum plants? What are the differences?



The principle of calcium injection in the furnace for desulfurization can be explained by the following two chemical equations:
CaCO3----heating-----CaO+CO2
CaO+SO2------------CaSO3

It can be seen that it is CaO, which is quicklime, that actually participates in desulfurization.

Therefore, adding quicklime can definitely desulfurize, and the desulfurization effect per unit mass of desulfurizer is obviously better than limestone.

Then, some people may ask, since quicklime has better desulfurization effect than limestone, why is limestone generally used as a desulfurization agent?

In fact, it is very simple, the price issue. Quicklime is prepared by calcining limestone, which is more expensive. Limestone can be decomposed at high temperature in the furnace to obtain quicklime. Of course, limestone is used.

As for whether the addition of limestone affects the thermal efficiency of the boiler, this is definitely influential, because reaction 1 in the desulfurization process is an endothermic reaction.