Steam Stripping for Recovery of Ammonia from Wastewater Using a High-Gravity Rotating Packed Bed

oleh: Min-Hao Yuan, Minh Viet Trinh, Yi-Hung Chen, Yong-Jhe Lu, Li-Pang Wang, Shikun Cheng, Zifu Li, Malee Santikunaporn, Channarong Asavatesanupap

Format: Article
Diterbitkan: MDPI AG 2024-09-01

Deskripsi

Steam stripping of ammonia from ammonia-rich wastewater (5000–20,000 mg/L) was conducted in a continuous-flow rotating packed bed (RPB) at a pH of 11. This study aimed to elucidate the influence of key operational parameters, including the steam-to-liquid ratio, rotational speed (ω), initial ammonia concentration, steam inlet temperature (T<sub>Si</sub>), and liquid inlet temperature (T<sub>Li</sub>), on critical performance metrics such as the ammonia removal efficiency (ARE), the volumetric liquid mass transfer coefficient (K<sub>La</sub>), and the concentration of the recovered ammonia solution (C<sub>R</sub>). The findings revealed that a C<sub>R</sub> of 22.88 wt.% was achieved under the optimal conditions of a steam-to-liquid ratio of 0.175 kg/kg, an initial concentration of 20,000 mg/L, a T<sub>Si</sub> of 120 °C, and a T<sub>Li</sub> of 70 °C. Key experimental factors, including the initial ammonia concentration, T<sub>Si</sub>, and T<sub>Li</sub>, significantly impacted the achievement of higher ARE and C<sub>R</sub> values. The K<sub>La</sub> values exhibited a decrease with the increase in the steam-to-liquid ratio, while they increased with ω. However, the K<sub>La</sub> remained relatively consistent with ω values within the range of 600 to 1200 rpm. In comparison with prior studies, steam stripping of ammonia exhibits a higher ARE than air stripping with RPB and a higher C<sub>R</sub> than conventional stripping methods. Moreover, RPB requires a smaller size to achieve equivalent ARE compared to conventional stripping apparatuses. Thus, the steam stripping process with RPB equipment emerges as a suitable method for ammonia recovery from ammonia-rich wastewater.