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

In the dissertation, the current treatment technologies of molasses alcohol wastewater are reviewed. The characteristics of Catalytic Wet Air Oxidation (CWAO) ,the application of CWAO in the treatment of organic wastewater and the research status quo of CWAO at present are elaborated. CWAO in the treatment of molasses alcohol wastewater is leading research direction. The main contents and results are presented as follows: 1. When Mn, Ni, Cu, Fe, Zn, Ba, Ce and La are the mostly active components of catalysts and the catalysts are prepared by sol-gel method, the results are as follows: (1) The catalyst made from La-Mn-Ni shows the better catalytic activity and stability. The optimal conditions of preparing the catalyst are that the ratio of La-Mn-Ni is 1:0.8:0.2(mol ratio), the calcination temperature is 7000C, and the calcination time is 6h; (2) Many experiments in which the catalysts are used in the treatment of molasses alcohol wastewater show that the CODCr of the treated wastewater reaches the 3rd grade of Comprehensive Wastewater Discharge Standard (GB9878-1996, China) when reaction time is 20min under 2950C or reaction time is 40min under 2800C, the dosage of the catalysts is 10g/l, and oxygen pressure is 4.5MPa. 2. When Mn, Ni, Cu, Zn and La are used as the active component, and Al₂O₃, zeolite Y, silica gel and coke which diameter is 4-6mm are used as the carrier and the catalysts are prepared by impregnation method , the result are as follows: (1) The activity of the catalyst is the best when Al₂O₃ is used among the 4 kind carriers. The catalyst of MnO 2/Al₂O₃ has the better catalytic activity and stability in treatment of molasses alcohol wastewater by CWAO . The optimal conditions of preparing the catalyst are that quantity of immersion is 0.2(g Mn(NO3)2/g Al₂O₃), the calcination temperature is 600～7000C, and the calcination time is 6h;(2) When the catalyst of MnO₂/Al₂O₃ is used in the treatment of molasses alcohol wastewater, the appropriate dosage of the catalyst is 300-500g/l.. Many experiments show that the CODCr of the treated wastewater reaches the 3rd grade of Comprehensive Wastewater Discharge Standard (GB9878-1996, China) when the reaction time is 40min under 2600C or the reaction time is 20min under 2800C or the reaction time is 10min under 3000C, the dosage of the catalyst is 500g/l, and oxygen pressure is 4.5MPa. 3. The factors and the regularities effecting CWAO in the treatment of molasses alcohol wastewater are researched chiefly. The results indicate: the CODCr removal ratio of wastewater treated by CWAO increases with the reaction temperature, reaction time, oxygen pressure and dosage of the catalyst, but the CODCr removal rate of wastewater increases inconspicuousness when the oxygen pressure and the dosage of the catalyst exceed specific quantity . Appropriate ratio of actual oxygen pressure to theory oxygen pressure is 4.7 . 4. The kinetics of CWAO in treatment of molasses alcohol wastewater is researched. when the catalyst of MnO2/Al2O3 is applied , the results indicate that when the ratio of actual oxygen pressure to theory oxygen pressure exceed 4.7,the kinetic parameters of CWAO in treatment of molasses alcohol wastewater are that the reaction order is 0 and 1 for oxygen and CODCr, respectively, and the activate energy is 1.19×104J/mol, the preexponential factor is 0.644min-1.