Flash desulfurization slurry waste heat recovery system and method

The invention provides a flash evaporation desulfurization slurry waste heat recovery system and method, and belongs to the technical field of boiler flue gas energy conservation, the flash evaporation desulfurization slurry waste heat recovery system comprises a desulfurization tower and a negative pressure flash evaporation device, the desulfurization tower is internally provided with a slurry area and a spraying area, and the slurry area is connected with the spraying area through a slurry circulating pipeline; a flash evaporation spraying layer and a flash evaporation slurry layer are arranged in the negative pressure flash evaporation device, the flash evaporation spraying layer and the flash evaporation slurry layer are connected with a slurry circulating pipeline through a slurry pipeline and a slurry backflow pipeline respectively, a first slurry adjusting valve is arranged on the slurry pipeline, and a second slurry adjusting valve is arranged on the slurry circulating pipeline; and the second slurry