Desulfurization tower is a kind of equipment for desulfurization treatment of industrial waste gas, mainly tower equipment, namely desulfurization tower. The large-scale desulfurization device used for flue gas desulfurization in coal-fired power plants is called flue gas desulfurization tower, and the small desulfurization and dust removal devices used for flue gas desulfurization of coal-fired industrial boilers and kilns are mostly called desulfurization dust collectors.
The working principle of the flue gas desulfurization tower is to clean the flue gas containing sulfur dioxide (SO2) with lye to absorb the sulfur dioxide in the flue gas. Sulphur dioxide in flue gas is actually acidic, and acidic sulphur dioxide is removed from flue gas by reacting with a suitable alkaline substance. The alkaline substances commonly used in flue gas desulfurization towers are limestone (calcium carbonate), quicklime (calcium oxide) and slaked lime (calcium hydroxide). Limestone is abundant and relatively inexpensive. Quicklime and hydrated lime are made by heating limestone. Other alkaline substances, such as sodium carbonate, magnesium carbonate, and ammonia, are sometimes used. The alkaline substance used reacts with the sulphur dioxide in the flue gas to form a mixture of sulfites and sulfates (depending on the alkaline substance used, these salts may be calcium, sodium, magnesium or ammonium). The ratio of sulfite to sulfate depends on the process conditions.
In some process, all sulfites are converted to sulfates. The reaction of sulfur dioxide with alkaline substances takes place in alkaline solutions (wet FGD technology) or on the wet surface of solid alkaline substances (dry or semi-dry FGD technology).