Method and device with a gas layered sieve plate for wet desulfurization

Abstract

A method and a device for wet desulfurization of flue gas to remove a sulfur dioxide(SO.sub.2) contained in flue gas discharged from thermal power stations and boilers are disclosed. In the method the device with a gas layered sieve plate for wet desulfurization of flue gas, an absorbing liquid improves reacting conditions by effecting it own circulation without using additional power due to the structural characteristics possessed by the device and flue gas is treated very satisfactorily thanks to high gas-liquid contact efficiency. In order to minimize power consumption and the size of the device but promote desulfurization to an unusual degree, an absorber is divided into an upper froth layer and a lower liquid layer by a single-stage gas dispersing plate with a large number of gas ejection holes bored therein. The absorber comprises a liquid downcomer which enables absorbing liquid which absorbed a sulfur dioxide from the froth layer to overflow when it rises higher than a proper height and then fall by a difference in liquid head produced between the froth layer and the liquid downcomer and a liquid riser which extends downward to a proper length from the gas dispersing plate and enables the absorbing liquid to rise above the gas dispersing plate for ejection to the extent of its fall, and so the absorbing liquid effects its own circulation at a high speed without using additional power. To raise adaptability to changes in boiler load, a number of V notches are formed at regular intervals at the upper end of an overflow weir.