Study On The Treatment Of Catalytic Wet Air Oxidation To Molasses Alcohol Wastewater

In this dissertation, the current treatment technologies of molasses alcohol wastewater were reviewed. The principle and properties of catalytic wet air oxidation (CWAO) were elaborated. The new methods of CWAO in the treatment to molasses alcohol wastewater were raised, and the foundational study about the application of CWAO was carried out. The main contents and results were presented as follows: 1. The characteristic and the pretreatment of molasses alcohol wastewater were studied. The results were as follows: (1) The wastewater was a high concentration and acid waste liquid. Some organic components of which polymerized above the temperature of 110℃,and some discomposed and formed charcoal when the temperature reached about 167℃.We couldn't find the polymeric compound or charcoal formed above the temperature of 240℃ in the present of oxygen. (2) We adjusted the pH value to 8.0 or so with the cream of line, then flocculated and settled these suspended matter with the flocculating agent of PHP-2 or the composite flocculating agent of PHP-2 and PAC before injecting the wastewater. The procedure and the optimum condition were as follows: The suitable recruitment of PHP-2 was 0.9mg/L; and the stirring velocity was 200rpm. Under this condition the suspended matter precipitated completely in 6 minutes. If we chose the composite flocculating agent of PHP-2 and PAC, the suspended matter precipitated completely in 5-7 minutes when the recruitment was 30mg/L.2. On the base of using the transitional elements and the rare earth elements, we prepared various types composite catalysts, and evaluated them in a intermittent magnetic stirring reactor. The results were as follows: (1) The catalytic composite of Cu-Fe oxides showed the better catalytic action, but the leaching of copper ions was not negligible. (2) Among the complex catalysts of Fe-Mn, the catalyst of Fe2O3-MnO2/γ-Al2O3 was finally selected as the most ideal type(the supporterγ-Al2O3 were prepared by microwave). The best molar ratio of the active components in the mixture was Fe:Mn:γ-Al2O3=3:1:1, and the suitable roast temperature was 600℃. The catalyst Fe:Mn:γ-Al2O3(3:1:1) could be the special catalyst in the treatment process of CWAO to the molasses alcohol wastewater. 3. The factors and the regularity affecting the process of CWAO for the treatment of molasses alcohol wastewater were studied chiefly. The results indicated: (1) The CODCr removal rate of organic pollutants increased with the increment of reaction temperature, reaction time, oxygen pressure and the dosage of the catalyst in the catalytic process of treating the molasses alcohol wastewater with the catalyst of Fe2O3-MnO2/γ-Al2O3(3:1:1), but the CODCr removal rate of organic pollutants didn't increase obviously with the increment of oxygen pressure and the dosage of the catalyst. (2) The appropriate oxygen supplied was as 3.4-4.6 times as that of the theoretic, and the optimum of the dosage of the catalyst was 10g/L. (3) Many time of experiments showed that the treated wastewater met the 3rd grade of Comprehensive Wastewater Discharge Standard (GB9878-1996, China) when reacting 30min under the temperature of 300℃ or reacting 1h under 280℃,4. We studied the kinetics of the catalytic wet air oxidation to molasses alcohol wastewater. The results indicated that the reaction order of organics pollutants was 1.18, and that of oxygen was 0 when the appropriate oxygen supplied was as 3.4-4.6 times as that of the theoretic. The constant of reaction rate was 1.178(L.mg-1)0.18.min-1 under the temperature of 280℃.