The invention provides a method and a device for promoting simultaneous removal of mercury and
fine particulate matters during wet
flue gas desulfurization by use of the water-
vapor phase change principle and aims to overcome the shortcomings that
flue gas in low in temperature and high in
humidity and PM2.5 and mercury cannot be effectively removed after wet desulphurization.
Coal-fired
flue gas subjected to wet desulphurization enters a water-
vapor phase change chamber, and normal-pressure saturated vapor is injected to enable
flue gas to be supersaturated; on one hand, the supersaturated water-vapor drags
gaseous mercury to be collected on the surfaces of particulate matters through both the
thermophoresis and diffusiophoresis actions, and on the other hand,
fine particulate matters on which particulate mercury is collected are taken as condensation nucleuses,
nucleation and condensation occur on the surfaces of the condensation nucleuses, so that the
fine particulate matters are increased in particle
diameter and
mass, and dust-containing drop mercury which is increased in size by condensation is finally removed by an efficient
demister. A conventional
coal-fired wet desulphurization device is improved by additionally arranging the water-
vapor phase change chamber behind a desulfurization
tower, so that once vapor is added, the wet desulphurization device can play the role of simultaneous removal of mercury and fine particulate matters. The method and the device can be widely used for wet
flue gas desulfurization in
coal-fired power plants and have huge
economic benefits and
social benefits.