Water-washing dedusting device for exhaust discharged from u-gas gasifier during start-stop period and dedusting process of water-washing dedusting device

The invention discloses a water-washing dedusting device for exhaust discharged from a u-gas gasifier during start-stop period and a dedusting process of the water-washing dedusting device. The water-washing dedusting device includes a start scrubbing tower below an exhaust outlet, the top of the start scrubbing tower is provided with an exhaust outlet pipe, a multistage spray device is arranged on the upper middle portion in the start scrubbing tower, a Pall-ring structure is arranged on the lower portion in the start scrubbing tower, and the side wall of the start scrubbing tower below the Pall-ring structure is communicated with an air inlet; the multistage spray device inside the start scrubbing tower is connected with a spray water circulation system and a spray water supply pipe. By independent design, research and development, the start scrubbing tower and the spray device in the scrubbing tower are installed, the spray waste water circulation system is designed and installed, thus a good dust removing