【Weekly Topic】Adjustment of pH value in gray and black water
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The book states that \"the practice of adding sodium hydroxide or ammonia water during slurry preparation to artificially adjust the pH value depends on the raw coal and the specific process conditions.\" Is this measure actually used in actual production? What are the considerations in reality and what is the outcome?
It must be used; otherwise, how can the pH value be controlled?
The pH value of the gasifier blackwater with a high solid content should be adjusted to range between 5.82 and 8.09. In addition, controlling the pH value of the blackwater also requires taking into account the solid content in it as well as the SiO2 content present in the gases within the blackwater. When the contents of Ca and Mg in the slurry are high, the pH value of the black water can be maintained between 5.5 and 7, giving it a weakly acidic nature, which helps to effectively prevent alkaline scaling. When the SiO2 content in the black water is high, its pH value can be kept between 7 and 8, resulting in a weakly alkaline environment that helps to prevent acidic scaling