臺灣博碩士論文加值系統

近年來，流體化床結晶技術(FBPRs)已經廣泛的被應用在處理含重金屬廢水上。而一般傳統的混凝方式處理重金屬廢水，易產生大量有害的污泥，且污泥必須經過脫水、固化、掩埋等處理程序，造成資源上大量的浪費。相反的，流體化床結晶技術處理重金屬廢水最主要的優點能使廢水達排放標準，生成的晶體可回收再利用，故不會有污泥的二次污染問題，符合現今環保技術的需求。本研究以流體化床結晶技術處理事業廢水中含高濃度鎳的廢水，藉由碳酸鈉的加入和廢水中的鎳形成碳酸鎳或氫氧化鎳固體覆蓋在擔體表面來進行反應槽之各項操作因子的探討，包括pH、藥劑進料莫耳比(CT/Ni)、迴流比(R)、進料廢水負荷量(Ni-loading)，試圖找出最理想的操作條件，以達到排放事業廢水的標準且得大量的結晶固體，並以SEM觀察晶體表面變化且對晶體之組成成分做定組成的分析。
實驗結果顯示pH值對結晶系統具有相當大的影響，當pH 9、CT/Ni為0.125/1、Ni-loading 274g/m2hr、上流表面速度在103.23m/hr時，晶體結晶比例約80﹪且處理後之廢水達放流水標準。當以上流表面速度(upflow superficial velocity)改變迴流比時，上流表面速度愈大(迴流比愈大)則床體底部的進料濃度被大量的稀釋，過飽和度隨之下降。因此，自發性的初成核被抑制而降低產生非結晶性碳酸鎳或氫氧化鎳固體的機會，故隨上流表面速度增大結晶比例愈高。pH 9、Ni-loading 、274g/m2hr、上流表面速度操作在69.28m/hr至103.23m/hr之間，結晶比例為50﹪至70﹪左右，當上流表面速度操作在117.72m/hr，床體的粒子部分被帶離床體，應避免在此區間操作。進料廢水負荷量分別在274 g/m2hr和550 g/m2hr之間，pH 9、CT/Ni 0.125/1、上流表面速度103.23m/hr，結晶比例分別80﹪和60﹪，但當在550 g/m2hr區間操作時，因初成核大量的產生，使得床底出現阻塞現象。此外，經由對晶體成分分析結果顯示，覆蓋在擔體表面的鎳鹽以Ni(OH)2為主，隨pH增高而Ni(OH)2的量漸增，當CT/Ni在0.5/1以上時，晶體成分幾乎以Ni(OH)2為主，此結果與NiCO3和Ni(OH)2的Ksp值相互的驗證。

In recent years fluidized bed pellet reactors (FBPRs) have been extensively applied in the removal of heavy metals from wastewater. In the traditional unseeded precipitation treatment of wastewater where a dissolved component has to be removed, the addition of precipitating chemicals results in the formation of sludge. Then the sludge produced must be transported to and disposed off in a waste landfill. On the contrary, a major advantage of the FBPRs is the production of a small amount of water-free, reusable pellets, without extra surplus sludge production. In this research, the crystallization process of a fluidized bed pellet reactor was studied in the treatment of the nickel-containing wastewater. Sodium carbonate was added as the reagent solution to form nickel carbonate and nickel hydroxide on the surface of the pellets in a fluidized pellet reactor. We investigated the effects of some important factors, including pH, CT/Ni feeding ratio, recirculation ratio and Ni-loading, on the performance of the fluidized bed crystallization technique.
The results showed that pH had a great effect on the crystallization efficiency of nickel and the optimal pH was about 9.0. At this pH value, the crystallization efficiency could be achieved about 80﹪at Ni-loading of 274g Ni per m2 of reactor cross-section per hour, upflow superficial velocity of 103.23 m/hr and feeding ratio CT/Ni of 0.125 mol/mol. A higher rate of upflow superficial velocity (i.e. higher recirculation ratio) would lead to a decrease in the degree of supersaturation. Therefore, the spontaneous nucleation of nickel carbonate and nickel hydroxide were inhibited and the crystallization efficiency of nickel carbonate and nickel hydroxide were increased. When the upflow superficial velocity was varied from 69.28 m/hr to 103.23 m/hr, the crystallization efficiency increased from 50﹪to 79﹪at Ni-loading of 274 g/m2hr and pH = 9. High upflow superficial velocity (e.q. 111.72 m/hr) would lead to carry-over of the pellets in the fluidized bed. When Ni-loading was varied from 274 to 550 g/m2hr at pH = 9, CT/Ni ratio of 0.125 mol/mol and upflow superficial velocity of 103.23 m/hr, the crystallization efficiency of nickel decreased from 80﹪to 60﹪. In operation of the Ni-loading of 550 g/m2hr ( high degree of supersaturation ), the distributor was often clogged by the fines of nickel carbonate due to the spontaneous nucleation. The crystallization material on the pellets consists mainly of nickel carbonate and nickel hydroxide. The analysis indicated that nickel hydroxide percentage increased in the crystallization of the pellets at higher value of pH. When CT/Ni feeding ratio was greater than 0.5, the crystallization material on the pellets was almost composed of nickel hydroxide.

指導教授推薦書
口試委員審定書
授權書 iii
簽署人須知 iv
誌謝 v
中文摘要 vi
英文摘要 viii
目錄 x
圖表目錄 xiii
第一章緒論 1
第二章文獻回顧 4
2.1平衡濃度與過飽和度 4
2.1.1可溶物系過飽和度的定義 6
2.1.2微溶物系過飽和度的定義 8
2.2過飽和溶液的介穩區 9
2.3晶體成核現象 13
2.3.1結晶與沈澱 13
2.3.2成核現象 13
2.4流體化床原理 18
2.4.1流體化現象 18
2.4.2流體化床的優缺點 20
第三章原理 21
3.1晶體成長基礎理論 21
3.2Two-step Model 21
3.3Burton-Cabrera-Frank Model 24
3.4流體化床的質傳式 26
3.4.1質傳現象 26
3.4.2質傳係數 26
3.5晶體成長動力式之係數求取法 29
3.6流體化床結晶技術的發展 32
3.7流體化床結晶技術之原理 38
3.7.1碳酸鎳的結晶原理 38
3.7.2顯著因子的探討 42
3.8流體化床結晶槽之質能平衡式 44
第四章實驗裝置與步驟 46
4.1實驗 46
4.1.1擔體材料 46
4.1.2實驗裝置 47
4.2實驗步驟 52
4.3實驗藥品 52
4.4分析儀器 53
4.5晶體成份之定量組成 54
4.5.1實驗背景 54
4.5.2實驗步驟 55
第五章結果與討論 56
5.1pH值的影響 56
5.2迴流比的影響 61
5.3廢水負荷量的影響 66
5.4進料藥劑莫耳比(pH control) 71
5.5進料藥劑莫耳比(without pH control) 76
5.6改變進料藥劑進流速度的影響 83
5.7 晶體SEM表面觀察與定量組成成份分析 88
5.7.1SEM表面觀察 88
5.7.2晶體成份分析 89
第六章結論 91
符號說明 95
參考文獻 97
附錄一 流體化床結晶技術晶體成長數據 101
附錄二 重金屬排放標準法令 108

1. Graveland A. and van Dijk J. C., de Moel P. J. and Oomen J.H.C.M.1983, "Developments in water softening by mean of pellet reactors." Journal AWWA . 75 , p619-625 .
2. van Ammers M., van Dijk J. C., Graveland A. and Nuhn P. A. 1986., "State of the art of pellet softening in the Netherlands. ", Water Supply 4 , p223-235.
3. van der Veen C. and Graveland A. 1988 ,. "Central softening by crystallization in a fluidized — bed process.", Journal AWWA . June , p51-58.
4. van Dijk J. C. and Braakensiek H. 1984, "Phosphate removal by crystallization in a fluidized bed. ", Wat Sci. Tech. 17, p133-142.
5. Eggers E., Dirzwager A. H. and van der Honing H. 1991 , "Full-scale experiences with phosphate crystallization in a crystalactor. ", Wat Sci. Tech. 24, p333-334.
6. Scholler M., van Dijk J. C. and Wilms D. A. 1987, "Recovery of heavy metals by crystallization in the pellet reactor. ", Environmental Technology, K. De Waal and W. Van den Brink(Eds). M. Nijhoff Publ., Dordrecht, p294-303.
7. Scholler M., van Dijk J. C. and Wilms D. 1991, "Fluidized bed pellet reactor to recover metals or anions. ", Metal Finishing , 89, p46-50.
8. Harms W. D. Jr. and Robinson R. B. 1992 , "Softening by Fluidized Bed Crystallizers. ", J. of Envi. Eng., 118, p513-529.
9. Seckler M. M., Bruinsma O. S. L. and van Rosmalen G. M. 1996a, "Phosphate Removal in a Fluidized Bed-I: Identification of Physical Processes. ", Wat. Res., 30, p1585-1588.
10. Seckler M. M., Bruinsma O. S. L. and van Rosmalen G. M. 1996b, "Calcium Phosphate Precipitation in a Fluidized Bed in Relation to Process conditions: A Black Box Approach. ", Wat. Res. , 30, p1677-1685.
11. Nielsen A. E. 1982,"Precipitetes: Formation Coprecipitation, and Aging. "Ch. 27, Treasite on Analytic Chem. Part  Section D, p269.
12. Nielsen A. E., J. M. Toft 1984a, "Electrolyte Crystal Growth Kinetics." J. of Crystal Growth , 67, p278.
13. Nielsen A. E. 1984b, "Electrolyte Crystal Growth Mechanisms.." J. of Crystal Growth , 67, p289.
14. Sohnel, O., J. Garside 1992, "Basic Principles and Industrial Application. " Redwood, London, P75.
15. Garside J. 1971, " The Concept of Effectiveness Factors in Crystal Growth. ", Chem Eng. Sci., 26, P1425-1431.
16. Karpinsk P. H. 1980, "Crystallization as a Mass Transfer Phenomenon. ", Chem. Eng. Sci. , 35, P2321-2324.
17. Tai C.Y., R. K. Pan 1985, "Growth Kinetics of Copper Sulfate Pentahydrate Crystal in Pure and Impure Systems. ", Journal of the Chin. I. Ch. E., 16(4), p379.
18. Budz J., P. H. Karpinski , Z. Nuruc 1984, "Influence of Hydrodynamics on Crystal Growth and Dissolution in a Fluidized Bed. ", AIChE J. , 30, p710-717.
19. Tournie P., C. Laguerie , J. P. Couderc 1979, "Correlations for Mass Transfer between Fluidized Spheres and a Liquid. ", 1979, Chem. Eng. Sci. , 34, p1247-1255.
20. Tai C. Y., C . Y. Chen , J. F. Wu 1985, "Crystal Dissolution and Growth in a Lean Fluidized-Bed Crystallizer. ", Chem. Eng. Comm. , 56, P329.
21. Lie Ding Shiau, Shueh Hen Cheng, Yung Chang Liu 1999, "Modelling of a Fluidized-Bed Crystallizer Operated in a Batch Mode. ", Chem. Eng. Sci. , 54 , p865-871.
22. Lie Ding Shiau and Yung Chang Liu 1998 , "Simulation of a Continuous Fluidized Bed Crystallizer — Perfect Classified Crystallizer Model. ", J. Chin. Inst. Chem. Engrs., 29(6), p445-452.
23. Kind M., and A. Mersmann 1990, "On supersaturation during mass crystallization from solution ", Chem. Eng. Technol.,13 , p50.
24. Basta N. , 1983, "Getting the Metal out of Spent Planting Baths. Chem. Eng. , 90(10), P22-25.
25. Chowdhury J. 1987, "New Routs Buoy Efforts to Trim heavy-metal Wastes. ", Chem. Eng. ,94(14), p26-27.
26. Kim B. M. 1981, "treamtment of metal-containing Wastewater with Calcium sulfide. ", AICHE Symp. Ser. 77, P39-48.
27. Thomas E. H., Vernon E. S. 1984, "Combined Removal od Cr, Cd and Ni from Wastes. ", Environ. Prog. 3(1), P12-25.
28. Kris A.Berglund, Basic concepts of crystal growth and nucleation.
29. Clifford Y. TAI 1997, "Crystallization kinetics revealed from experimental data analyzed by the two-step growth model ", Journal of chemical engineering of japan , 30 (3).
30. Ping Zhou, Ju-Chang Huang, Alfred W. F. LI. And Shirly Wei 1999, "Heavy Metal Removal From Wastewater in Fluidized Bed Reactor. ",Wat. Res. , 33 (8), p1918-1924.
31. Tournie, P., C. Laguerie , J. P. Couderc 1979, "Correlations for Mass Transfer Between Fluidized Spheres and a Liquid. ", Nat Eng. Sci., 34 , p1247.
32. D.Wilms, A. van Haute, J. van Dijk and M. Scholler, "Recovery of nickel by crystallization of nickel carbonate in a fluidized-bed reactor ", p449-456.
33. John Baker-Counsell. 1987, "Pellet Reactor Improves Treatment of Metal Solution. ",Waste Treatment., p47-48.
34. D. Wilms, A. van Haute, J. van Dijk and M. Scholler, "Recovery of Nickel by Crystallization of Nickel Carbonate in a Fluidized-Bed Reactor. ", p449-456.
35. 行政院環保署 , ”事業廢水處理技術指引及成本分析 ”, 81年1月
36. 行政院環保署 , ”事業廢水處理技術改善評鑑與管理手冊 － 表面處理電鍍及金屬 ”, 83年1月.
37. 陳寶祺 1992, ”微溶物係之沈澱與結晶”, 國立台灣大學化學工程學研究所, 博士論文.
38. 李茂松1997, ”無機廢水資源回收再利用處理技術－FBC案例 ”, 工業污染防治 , 62 , p150-167.
39. 曹志明 1994, ”氟化鈣結晶動力學之研究”,國立台灣大學化學工程學研究所, 碩士論文.
40. 陳仲裕 1995, ”碳酸鈣在流體化床中成長動力學之研究”,國立台灣大學化學工程學研究所, 碩士論文.
41. 李茂松 1993, ”流體化床結晶技術在無機廢水處理上應用性研究”,私立中原大學化學研究所, 碩士論文.
42. 陳政澤 1995, ”流體化床結晶反應槽回收廢水中重金屬鎘研究”,國立中央大學環境工程學研究所, 碩士論文.