化學混凝程序去除煙氣脫硫廢水中硼的研究

Chemical Coagulation Process for the Removal of Boron from Flue Gas Desulfurization Wastewater

邵綠揚(Lyu-Yang Shao)

指導教授 ： 李奇旺

淡江大學/工學院/水資源及環境工程學系碩士班/碩士(2022年)

https://doi.org/10.6846/TKU.2022.00196

摘要

本研究以化學混凝程序，利用鐵作為混凝劑，去除煙氣脫硫廢水中 的硼。處理了來自於火力發電廠的廢水，並分析了會影響煙氣脫硫廢水 中硼的去除效率的因素。
使用三氯化鐵作為混凝劑的處理結果顯示，最適合的pH環境是8，且混凝劑對硼的摩爾比越大，硼的去除效率越高。初始廢水中硼的濃度越大，硼的去除效率越高。通過硼去除效率和廢水初始硼濃度之間的模型曲線將實驗數據整理，設計三階段處理程序以針對較高濃度硼的去除。結果顯示，即使處理初始硼濃度為1600mg/L 的煙氣脫硫廢水，也能達到80%以上的去除效率。在本系統中，鈣離子和鎂離子也獲得了與硼相似的去除效率趨勢。鈣離子和鎂離子分別在其初始廢水濃度為750mg/L和5000mg/L的三階段處理程序中，達到78%和60%以上的去除效率。在本研究程序中使用氫氧化鈣作為pH調節試劑，在不降低硼的去除效率的同時可以使得污泥更易沈降。

關鍵字

化學混凝程序 ； 硼 ； 氫氧化鈣 ； 三氯化鐵 ； 三階段處理程序 ； 煙氣脫硫廢水

並列摘要

In this study, a chemical coagulation (CC) process was used to remove boron (B) from flue gas desulfurization (FGD) wastewater using Fe(III) as a coagulant. In the treatment of FGD wastewater from coal-fired power plants, the factors affecting the boron treatment process in the FGD wastewater were analyzed. The experimental results show that the most suitable pH environment is 8 when using ferric chloride (FeCl3) as coagulant, and the higher the molar ratio of Fe(III) to B, the higher the removal efficiency of B. The higher the initial concentration of B in the wastewater, the higher the removal efficiency of B. The experimental data were compiled and fitted with a model to correlate B removal efficiency and initial B concentration in wastewater for various Fe(III)/B molar ratios, and a three-stage treatment process was proposed to target the removal of higher concentrations of B. The results show that the removal efficiency of more than 80% can be achieved even with the FGD wastewater with an initial B concentration of 1600 mg/L. The removal efficiencies of calcium (Ca2+) and magnesium (Mg2+) were over 78% and 60% in the three-stage treatment process with their initial Ca2+ and Mg2+ wastewater concentrations of 750 mg/L and 5000 mg/L, respectively. The use of calcium hydroxide (Ca(OH)2) as a pH adjustment reagent in the coagulation process can make the sludge easier to settle without reducing the B removal efficiency.

並列關鍵字

Chemical coagulation process ； Boron ； Calcium hydroxide ； Ferric chloride ； Three-stage treatment process ； Flue gas desulfurization wastewater

參考文獻

REFERENCES

[1] W. Wang, Z. Li, J. Lyu, H. Zhang, G. Yue, and W. Ni, (2019) “An overview of the development history and technical progress of China’s coal-fired power industry” Frontiers in Energy 13: 417–426. doi: 10.1007/s11708-019-0614-2.

[2] Energy Bureau of the Ministry of Economic Affairs. Energy Supply in Taiwan, Bureau of Energy. https://www.moeaboe.gov.tw/ECW/english/content/ ContentLink.aspx?menu_id=1540, Accessed: 2020-12-07.

[3] J. Bao, X. Zhao, R. Tian, and C. Jia, (2011) “Researching into Microbial- Limestone New Wet Flue Gas Desulfurization Method” 2011 International Conference on Remote Sensing, Environment and Transportation En- gineering: 677–679. doi: 10.1109/RSETE.2011.5964367.

[4] U.S. Department of State. China-US Joint Announcement on Climate Change. https://www.state.gov/u-s-china-joint-statement-addressing-the- climate-crisis/, Accessed: 2020-12-19.