Supersonic gas-liquid separation energy-saving demisting device and demisting method thereof

The invention relates to the field of demisters in a wet desulfurization and denitrification process, in particular to a supersonic gas-liquid separation energy-saving demisting device and a demisting method thereof. The device comprises a pressurized flue gas inlet system, a flue gas compression system, a multi-stage reducing coupling Laval nozzle gas-liquid separation pipeline, a flue gas inlet and exhaust control system and a liquid collector, wherein a flue gas inlet of the flue gas compression system is communicated with the pressurized flue gas inlet system; the multi-stage reducing coupling Laval nozzle gas-liquid separation pipeline is communicated with a smoke outlet of the smoke compression system, and is used for accelerating smoke entering the multi-stage reducing coupling Laval nozzle gas-liquid separation pipeline to supersonic speed so as to realize gas-liquid separation of the smoke at the tail end of a Laval nozzle of the multi-stage reducing coupling Laval nozzle gas-liquid separation pipeli