Experimental Study of Combined Effects of Liquid-Solid Flow Erosion and Alkaline Acid Water Corrosion in Coal Water Slurry Gasification Unit

The combined effect of liquid-solid erosion and alkaline acid water corrosion (mainly NH₄HS corrosion) always speed up wall thinning, punching, even breaking up leading to dangerous medium leakage and shorting the running period of coal water slurry gasification units. Comparison with three experimental date sets involving deionized water, NH₄HS and deionized water, and particles and NH₄HS solution are conducted in terms of loss weight amounts of SA106 Gr.B steel. This work aims to investigate the thinning damage rule under the combined effect of pulverized coal particle erosion and NH₄HS solution corrosion, furthermore, a novel reduction rate prediction model including some key factors of NH₄HS and particle concentrations and flow velocity is proposed to guide erosion shield for coal water slurry gasification units. The results show that the particle concentration has a small effect on particle erosion at a low liquid-solid flow velocity (3m/s). There is a shield effect on the reduction rate near wall until to 6% of particle concentration, therefore, flow velocity plays a dominant role for erosion at 6% of particle concentration. With the increase of NH₄HS concentration or flow velocity, the erosion rate increases gradually. The particle concentration has less emphasis on the reduction rate than NH₄HS concentration or flow velocity. Higher particle concentration is beneficial for avoiding the damage of corrosion films, and then inhibits eroding from NH₄HS solution.