Dry desulfurization is also called dry flue gas desulfurization. Dry flue gas desulfurization is divided into two categories:
One is desulfurization in the furnace, that is, CaCO3 sprayed into the furnace is calcined at high temperature to decompose into CaO, which reacts with SO2 in the flue gas to form calcium sulfate, which is fixed in the ash;
The second is medium and low temperature flue gas desulfurization. There are many types, such as SDS sodium-based dry technology, FGD circulating fluidized bed technology, SDA sodium-based semi-dry technology, electron beam irradiation and activated carbon adsorption, etc., to achieve SO2 removal, collectively referred to as Dry flue gas desulfurization technology. Its advantages are simple process, no sewage and acid treatment problems, low energy consumption, especially the high temperature of the flue gas after purification, which is conducive to the diffusion of chimney exhaust, and does not produce "white smoke" phenomenon. The gas does not need to be heated again, and the corrosiveness is small;
Technical features:
1) Its desulfurization mechanism, sodium bicarbonate (NaHCO3) is activated under the action of high-temperature flue gas, forming a microporous structure on the surface, just like popcorn being popped, the reaction is fast and sufficient, and it can be completed in 2 seconds.
2) In the reactor, flue and bag filter, the superfine powder of desulfurizer has always reacted with the SO2 in the flue gas. The entire device has a compact structure, small size, reliable operation, and a desulfurization efficiency of more than 99%.
3) The load adaptability of the device is good, and the flue gas flows at a high speed in the reactor, which overcomes the wall sticking problem that may occur in the traditional semi-dry desulfurization reactor;
4) Produce by-product Na2SO4, which is recovered by bag filter and used as a chemical product. The by-product of desulfurization is dry, and no water is produced in the system. The final product has good fluidity and is suitable for pneumatic conveying.
5) SO3, HCl, HF and other acidic media in the flue gas are absorbed and purified at the same time. After desulfurization, the flue gas can be discharged directly without heating, which solves the problem of "white smoke".
6) Adopting the combined process of SDS desulfurization first and SCR denitrification later, creating excellent conditions for simultaneous flue gas desulfurization and denitrification. The SOx concentration in the flue gas has a great impact on the life of the medium and low temperature SCR denitration catalyst, and even causes the catalyst to be poisoned and blocked, which affects the stable operation of the system. The flue gas "desulfurizes first, then denitrifies" to solve the above problems.