According to the status of desulfurizer and desulfuration reaction products, they can be divided into wet process, dry process and semi-dry process. 

1. Wet fgd process the process flow, form and mechanism of wet fgd are almost the same in the world, the main method is to absorb SO2 from flue gas with alkaline solution as desulfurizer. Wet fgd process includes Limestone / lime-gypsum process, seawater process, double alkali process, sodium sulfite circulation process and magnesium oxide process. 

2. The application of dry fgd process in power plant flue gas desulfurization began in the early 1980s. Dry Desulfurization process mainly includes: charged dry absorbent injection desulfurization, electron beam processing method, adsorption method, etc. . 

3. The semi-dry fgd process combines the advantages of wet fgd and dry fgd, and has a broad application prospect. The semi-dry fgd process includes spray drying, circulating fluidized bed, humidifying ash circulation, flue gas injection and so on. At present, the wet flue gas desulfurization technology is dominant, and the dry and semi-dry flue gas desulfurization technology is also developing.