The gas is neutralised because the limewater reacts with sulphur dioxide, which gets rid of most of the sulphur dioxide to form solid calcium sulfate and water (home.lcusd). The chemical formulae of this process, when using limewater is: .
Ca(OH)2(aq) + SO2(g) → CaSO3(s) + H2O(g) .
[Limewater + Sulphur dioxide Calcium sulphite + Water].
A major advantage of a wet scrubber is that it collects dust particles as well as sulphur dioxide and sometimes, oxides of nitrogen. This makes the wet scrubber extremely efficient and a little bit easier to maintain. Also, in most countries, power stations are legally required to have some type of Flue gas desulphurisation apparatus (mostly wet scrubbers). This highly lowers the chance of highly acidic rain all over the world. Wet scrubbers can also handle heat really well. This is very helpful as power stations are extremely warm and have loads of flammable substances. Even though wet scrubbers are very useful, they do have some limitations. One of the most important ones is the economic limitation. Wet scrubbers are extremely difficult to maintain because the metal corrodes extremely easily because of all the reactions that take place in the wet scrubber (globalspec). Furthermore, the wet scrubber has to be made extremely precisely with proper construction materials. If they are not constructed properly, the process might get messed up. Wet scrubbers also need extremely high power to collect and clean all the flue gas properly. Sometimes, wet scrubbing can result in wastes that contain alkali like sulphate, sulphite and bisulfite (sciencedaily). Even though sulphate can be removed by reverse osmosis and other desalination methods, they are extremely expensive and so, a lot of companies don't bother with it. To avoid disposing of the waste (or 'slurry') after wet scrubbing, a lot of companies illegally dump the slurry in a water body to avoid excessive cost.
