温度对氨吹脱工艺中氨扩散传质的影响

Effect of temperature on ammonia diffusion mass transfer in air-stripping technology

研究低气速下的氨吹脱系统,建立了定量的氨扩散传质动力学模型,分析系统温度对氨扩散传质的影响。结果表明,氨吹脱过程中,在废水pH值大于12的条件下,氨分子大部分通过气泡扩散,只有极少量通过液相表面扩散;氨的气液传质阻力主要来自于气膜;随着系统温度的升高,气泡直径略微减小,气泡上升时间基本稳定,液相总传质系数迅速增大,气液传质阻力大幅降低。

Ammonia air-stripping system under low gas velocity was investigated, quantitative ammonia diffusion mass transfer dynamics was established, and the effect of system temperature on ammonia diffusion mass transfer was analyzed. The experimental results reveal that, as pH 〉12, a majority of ammonia molecules diffuse through bubbles and only a few ammonia molecules diffuse through the liquid surface, which can almost be neglected. As the system temperature increases, the bubble diameter decreases lightly, the bubble rising time remains comparatively stable, the overall liquid phase mass transfer coefficient grows quickly, and the gas-liquid mass transfer resistance decreases greatly.