The impact of inlet flash evaporation conditions on erosion damage characteristics of coal gasification black water angle valve and prevention strategies

Abstract

In view of the three-stage flash evaporation system of the coal gasification plant, a combination of theoretical analysis and numerical simulation was used to establish the erosion damage evaluation model in the black water angle valve. The influence of the inlet flash evaporation ratio on the inlet velocity, the outlet flash evaporation ratio and the outlet velocity of the low-pressure black water angle valve are systematically studied, the mechanism of erosion damage to the carbon steel valve body by the solid medium in black water was analyzed according to the micro-cutting theory. The results show that the inlet velocity w 1, the outlet flash evaporation ratio x 2, the outlet velocity w 2 of angle valve have linear correlation with the inlet flash evaporation ratio x 1.The upstream volume erosion ratio of the angle valve at the inlet flash ratio x 1 = 3 wt.% is 114 times as much as that at zero inlet flash ratio. Meanwhile, the downstream volume erosion ratio of the angle valve at x 1 = 3 wt.% is only 2.7 times as much as that at zero inlet flash ratio. The prevention strategies to reduce the erosion damage to black water angle valve are proposed by inhibiting the inlet flash evaporation ratio and reducing the inlet flow rate etc. This study is expected to provide guidance for the erosion resistance design and operation of the black water angle valve.