System and method for reducing dust content of BGL lignite gasification raw gas

The invention discloses a system and a method for reducing the dust content of BGL lignite gasification raw gas. The system comprises a BGL gasification furnace, a gasification venturi scrubber, a gasification waste heat boiler, a gasification separator, a scrubbing tower, a conversion venturi scrubber, a conversion separator, a cyclone separator and a conversion dust removal tank, comprising the following steps: S1, primary Venturi washing; s2, washing in a washing tower; s3, carrying out secondary Venturi washing; s4, separating by a cyclone separator; and S5, dust removal groove separation. The content of the raw gas treated by the system and the process reaches 0.04-0.06%; the system pressure difference of the conversion device is stabilized at 320 KPa, the system operation is very stable, and the stable duration can reach more than 12 months; the washing water of the conversion separator is recycled through the conversion washing water buffer tank and then is conveyed to the washing tower to spray and wa