1. Introduction to limestone-gypsum desulfurization process:

Limestone-gypsum method uses limestone as a desulfurizer. After adding water, it is made into limestone slurry. It is in full contact with the flue gas in the absorption tower. The sulfur dioxide in the flue gas reacts with the limestone in the slurry. The reaction product is calcium sulfite. The by-product calcium sulfate (gypsum) is formed by oxidative aeration, and finally a calcium sulfite and calcium sulfate solution is formed. The forced oxidation process is adopted, and the final reaction product is a calcium sulfate solution, which is dehydrated and dried to form gypsum.

Second, the chemical principle:

The main chemical reactions in the absorption tower are:

CaCO3+SO2=CaSO3+CO2

CaSO3+O2+2H2O=2CaSO4·2H2O

Third, the system consists of:

The whole desulfurization process system is composed of a flue gas system, an SO2 absorption system, a limestone slurry preparation system, a gypsum slurry discharge system, a slurry discharge system, and a wastewater treatment system.