超临界水氧化处理垃圾渗滤液的响应面法优化

Optimization of supercritical water oxidation for landfill leachate treatment by response surface methodology( RSM)

在间歇式反应釜上采用超临界水氧化法处理垃圾渗滤液.运用中心组合设计研究了反应温度(400～500℃)、压力(24～28 MPa)、反应时间(5～10 min)和氧化系数(1.5～2.5),以及它们的交互作用对COD、氨氮去除率的影响,同时通过响应面法分析拟合出COD、氨氮去除率的二次回归方程,得到最优工艺条件.结果表明,各因素对COD去除率的影响主次作用排序为:反应压力>温度>氧化系数>反应时间;各因素对氨氮去除率的影响主次作用排序为:反应温度>压力>氧化系数>反应时间,而影响因素之间的交互作用对两者去除效果的影响却不明显.所得拟合方程对COD、氨氮去除率的预测误差分别小于±4%、±9%.拟合方程所得最佳实验条件为:时间5 min、温度496.05℃、压力27.69MPa、氧化系数2.44,此时COD的去除率可以达到98.31%、氨氮去除率可以达到95.69%.

The landfill leachate was treated by supercritical water oxidation technology with a batch reactor. Central composite design （CCD） experiment was used to evaluate the effects of temperature （400～500 ℃）, pressure （24～28 MPa）, oxidation coefficient （1.5～2.5）, residence time （5～10 min） and their interactive effects on COD and NH4＋-N removal efficiencies, and the quadratic regression models were obtained by the response surface analysis. Results indicated that the effects on COD removal efficiency were in the order： pressure〉 temperature〉 oxidation coefficient〉 residence time, and that the order on NH4＋-N removal efficiency were temperature〉 pressure〉 oxidation coefficient〉 residence time. The interactive effects on both COD and NH4＋-N removal efficiencies were not significant. The forecast error of the quadratic regression models on COD and NH4＋-N removal efficiencies were less than ±4% and±9%, respectively. The optimum parameters within the experimental range were： 496.05 ℃, 27.69 MPa, oxidation coefficient of 2.44 and residence time of 5 minutes. Under the optimized conditions, the COD and NH4＋-N removal efficiency can reach 98.31% and 95.69%, respectively.