Catalytic flue gas desulfurization device and catalytic flue gas desulfurization tower

The utility model discloses a catalytic flue gas desulfurization device and a catalytic flue gas desulfurization tower. The device comprises a desulfurization reactor, the interior of the desulfurization reactor is divided into a flue gas distribution layer, a catalyst placement layer and a flue gas overflow layer from bottom to top, a gas distribution supporting structure is arranged in the flue gas distribution layer, a catalyst is placed in the catalyst placement layer above the gas distribution supporting structure, and the flue gas overflow layer is arranged on the catalyst placement layer. The desulfurization reactor is further provided with a first openable operation opening, a second openable operation opening and a third openable operation opening, a gas inlet of the desulfurization reactor is formed in the side face of the flue gas distribution layer, and a gas outlet and the first openable operation opening are formed in the top face of the flue gas overflow layer. The second openable and closable