薄膜蒸餾技術應用在中鋼煉焦廢水氨氮脫除之可行性研究

Application of Membrane Distillation to Remove Ammonia from Coking Wastewater in China Steel Corporation

林伯勳(P. H. Lin) ； 葉茂淞(M. S. Yeh) ； 洪仁陽(R. Y. Hong) ； 徐淑芳(S. F. Hsu)

《鑛冶：中國鑛冶工程學會會刊》 59卷2期 (2015/06) Pp. 108-119

https://doi.org/10.30069/MM.201506_59(2).0009

摘要

106年12月31日起環保署將針對化工業施行放流水氨氮排放管制，其限值為20 mg/L。中鋼放流水氨氮約80~90%來自於煉焦廢水，中鋼未來將使用生物處理程序進行氨氮脫除，但因進流煉焦廢水之氨氮濃度過高，須以物化法進行前處理，因此協同工研院開發薄膜蒸餾技術（MD），分離並移除煉焦廢水之氨氮。本研究以實驗室試驗評估PP及PTFE兩種材質薄膜、水及硫酸兩種氨吸收劑，並將MD處理後之氨氮濃度目標訂為＜300 mg/L。研究結果顯示PTFE較PP膜適用於直接接觸式MD（DCMD）來進行煉焦廢水氨氮分離；而對於煉焦廢水所含之氨氮濃度（平均~650 mg/L），硫酸較水更適合做為氨氮之吸收劑。以PTFE為DCMD模組配合硫酸為氨氮的吸收劑，在煉焦廢水pH值10.5~11.5時，其吸收通量約為1.7 g-N/m2.hr，並可將廢水中之氨氮處理至＜300 mg/L。此外，將DCMD分離氨氮所產生之硫酸銨，再以真空式MD（VMD）配合冰水為吸收劑進行氮氨分離，可產生至少3%的氨水做為回收利用。

關鍵字

煉焦廢水 ； 薄膜蒸餾

並列摘要

China Steel Corporation (CSC) has to keep the ammonia nitrogen (NH_3-N) concentration in the wastewater under 20 mg N/L before disposal. Eighty to 90% of NH_3 in CSC wastewater effluent is from the coking wastewater that will be treated by a biological process. However the NH_3 concentration (＞300 mg N/L) in the coking wastewater is too high for the biological treatment. Thus, CSC cooperated with the Industrial Technology Research Institute (ITRI) to develop a membrane distillation (MD) technique to reduce the coking wastewater NH_3 concentration to less than 300 mg N/L. The objectives of this study are to evaluate different membrane materials and receiving solutions for the MD treatment to reduce NH_3 concentration of coking wastewater to less than 300 mg N/L and to recover ammonia solution for reuse. Our experimental results showed that the PTFE hollow fiber MD module using sulfuric acid as a receiving solution can achieve a receiving flux of 1.7 g-N/m^2.hr and remove NH_3 in the coking wastewater to less than 300 mg N/L. The NH_3 in the converted ammonium sulfate ((NH_4)_2SO_4) was then recovered by vacuum membrane distillation (VMD) using ice water as the receiving solution to produce 3% ammonia solution.

並列關鍵字

coking wastewater ； membrane distillation ； PTFE