Xuan Zhang , Ping Wang , Haoyuan Dou , Jiaquan Chen , Lele Chen , Shiming Xu
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引用次数: 0
Abstract
This study proposes air gap diffusion distillation (AGDD) for recovering ammonia from ammonia nitrogen wastewater. The influences of several key parameters on the AGDD performance have been explored. The findings indicate that increasing the feed temperature improves the concentration factor (CF) and reduces the specific thermal energy consumption for ammonia recovery (STEC-N). Cooling water temperature on ammonia flux is higher than that of water flux. An increase in feed flowrate attenuates the boundary layer, substantially enhancing the ammonia flux relative to the water flux and boosting the CF. The effect of feed concentration on total flux is determined to be insignificant. When the air gap thickness is less than 8 mm, molecular diffusion dominates the mass transfer in the air gap, the water flux and ammonia flux decrease with the increase of the air gap thickness, and the CF reaches a peak of about 5.7 near 5 mm. However, when the air gap thickness is greater than 8 mm, natural convection dominates the mass transfer in the air gap. This weakens the negative impact of increased air gap thickness on total flux. This leads to a certain increase in CF, which is more pronounced at higher temperatures. Finally, a dimensionless equation for the mass transfer within the air gap was determined from temperature measurements at different spatial locations within the AGDD unit.
期刊介绍:
ChERD aims to be the principal international journal for publication of high quality, original papers in chemical engineering.
Papers showing how research results can be used in chemical engineering design, and accounts of experimental or theoretical research work bringing new perspectives to established principles, highlighting unsolved problems or indicating directions for future research, are particularly welcome. Contributions that deal with new developments in plant or processes and that can be given quantitative expression are encouraged. The journal is especially interested in papers that extend the boundaries of traditional chemical engineering.