A new wet limestone-gypsum process for flue gas desulfurization (FGD) has been developed. The main difference compared to a conventional wet FGD process is the ability of the new process to utilize granular limestone directly as a desulfurizing reagent. Thus, the pulverizing of limestone, which causes power consumption, can be avoided. The performance of the wet FGD process using granular limestone was confirmed to be equal to or higher than that of a conventional process in various tests. Tests were also performed in a 2000 m(Normal)(3)/h demonstration plant introducing actual flue gas of various types of coals at Matsuura Thermal Power Station of the Electric Power Development Co., Ltd. (EPDC) in Japan. It was also confirmed that the desulfurization performance of the granular limestone FGD process was not decreased by aluminum-fluorine-containing compounds in the absorbing slurry as much as in the pulverized limestone case. In this new wet FGD process, gypsum quality was also higher than that in a conventional wet FGD process.