臭氧接触氧化模型及臭氧接触池优化研究

发布时间：2018-11-03 10:03

【摘要】：截至2013年,中国已有75个饮用水厂采用臭氧-生物活性炭工艺对水进行深度处理。然而,在臭氧接触池的设计和运行中,普遍存在臭氧总投加量和三段式臭氧投加比确定不合理的问题。因此,研究基于臭氧接触池的臭氧接触氧化模型,对臭氧接触池中臭氧的传质和反应进行模拟,具有重要的实际意义。本文建立了基于鼓泡柱的臭氧接触氧化模型,并通过研究臭氧在地下水和腐殖酸配水中的传质和氧化效果对模型进行了验证。在此基础上,建立了基于臭氧接触池的臭氧接触氧化模型,并提出了优化臭氧投加比和总臭氧投加量的方法。研究表明:(1)基于双膜理论和臭氧反应动力学,分别在臭氧降解为一级反应和非一级反应两种情况下,建立了臭氧接触传质模型。当反应符合一级反应时,得到了模型的解析解;当反应不符合一级反应时,分别基于有机物消耗和臭氧消耗,得到了模型的数值解。(2)分别以地下水和腐殖酸配水作为水源,对该模型进行验证。结果表明,以地下水作为水源时,该模型能准确预测出水液相臭氧浓度和尾气臭氧浓度,误差不超过20%;出水液相臭氧浓度随着进气浓度、进气流量和水深的增加而增加,随着进水流量的增加而减少,在相同条件下逆向流比同向流传质效率更高。当以腐殖酸配水为水源时,臭氧的降解过程不符合一级反应动力学。此时,若以基于臭氧消耗的臭氧反应动力学模型对臭氧消耗曲线进行拟合,其中的臭氧反应速率常数和臭氧消耗量之间呈指数关系,此时对不同臭氧投加量下出水液相臭氧浓度进行拟合,拟合效果较好,误差小于18%。(3)建立了基于臭氧接触池的臭氧传质氧化模型,并分析了其灵敏度。在此基础上,对臭氧接触池进行优化。此时,需要首先在某一个臭氧总投加量下,根据臭氧利用率最高,确定三段的臭氧投加比。在此基础上,根据出水中余臭氧浓度调整总臭氧投加量。结果显示,对于三种不同性质的水,随着水质消耗臭氧速率从慢到快,其臭氧投加比分别为7:3:0,4:4:2和4:3:3,总臭氧投加量分别为0.9~1.1 mg/L,1.1~1.3 mg/L和1.5~1.7 mg/L。在本文中,通过测定某水质的臭氧衰减曲线,可以确定臭氧接触池总臭氧投加量和三段式臭氧投加比,对水厂的臭氧接触池优化运行具有一定的指导意义。
[Abstract]:As of 2013, 75 drinking water plants in China have adopted ozone-biological activated carbon (BAC) process for advanced treatment of water. However, in the design and operation of the ozone contact tank, the problems of the total ozone dosing and the determination of the three-stage ozone dosing ratio are generally unreasonable. Therefore, it is of great practical significance to study the ozone contact oxidation model based on the ozone contact tank and to simulate the mass transfer and reaction of ozone in the ozone contact tank. In this paper, a model of ozone contact oxidation based on bubbling column is established, and the model is verified by studying the mass transfer and oxidation effect of ozone in groundwater and humic acid mixed water. On this basis, the ozone contact oxidation model based on the ozone contact tank is established, and the method of optimizing the ozone dosing ratio and the total ozone dosage is put forward. The results show that: (1) based on the dual-membrane theory and ozone reaction kinetics, the ozone contact mass transfer model is established under the condition that ozone degradation is first order reaction and non-first-order reaction, respectively. When the reaction accords with the first-order reaction, the analytical solution of the model is obtained. When the reaction is not in accordance with the first-order reaction, the numerical solution of the model is obtained based on the depletion of organic matter and ozone consumption, respectively. (2) the groundwater and humic acid are used as the source of water, respectively, and the model is verified. The results show that the model can accurately predict the ozone concentration in the effluent liquid phase and the ozone concentration in the tail gas when the groundwater is used as the water source, and the error is less than 20%. The ozone concentration in the effluent increases with the increase of inlet air concentration, inlet air flow rate and water depth, and decreases with the increase of influent flow rate. Under the same conditions, the reverse flow is more efficient than that of the same flow. When humic acid is used as the source of water, the degradation of ozone does not conform to the first-order reaction kinetics. In this case, if the ozone depletion curve is fitted with a kinetic model of ozone reaction based on ozone depletion, there is an exponential relationship between the ozone reaction rate constant and the ozone consumption. At this time, the ozone concentration of effluent liquid phase under different ozone dosages is fitted, and the fitting effect is better, and the error is less than 18. (3) the ozone mass transfer oxidation model based on ozone contact tank is established and its sensitivity is analyzed. On this basis, the ozone contact tank was optimized. At this time, it is necessary to first determine the ozone dosing ratio of the three stages according to the highest ozone utilization under a certain total ozone dosage. On this basis, the total ozone dosage is adjusted according to the residual ozone concentration in the effluent. The results show that with the ozone depletion rate of water from slow to fast, the ozone dosing ratio is 7: 3: 0, 4: 4: 2 and 4: 3: 3, respectively, and the total ozone dosage is 0.9% 1.1 mg/L,. 1.1 1. 3 mg/L and 1. 5 1. 7 mg/L. In this paper, by measuring the ozone attenuation curve of a certain water quality, the total ozone dosage and the three-stage ozone dosing ratio of the ozone contact tank can be determined, which has certain guiding significance for the optimal operation of the ozone contact tank in the water plant.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU991.2

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