湿式氧化法处理煤气废水研究

发布时间：2018-08-20 16:19

【摘要】：由于煤气废水中含有大量的有机污染物和高浓度的氨氮,这些污染物很难通过生物降解处理掉,导致出水很难达到废水的排放要求和标准,需要进行深度处理和处置。高级氧化法在去除污水中难降解有机物中表现出诸多的优势,是主要方法之一,因此在给水处理中已得到了广泛的应用。本文采用湿式氧化法对煤气废水进行深度处理,研究煤气废水在湿式氧化反应体系中降解的特性和反应机理,为煤气废水的高温、高压处理提供有效的指导和有益的借鉴。考察了湿式氧化技术处理煤气废水中的主要影响参数,如反应压力、反应温度、反应停留时间、氧化剂用量等,在充足的氧化剂用量条件下,湿式氧化技术在反应的过程中表现出了良好的氧化效能和处理能力,得到了最佳污染物去除条件:反应温度为310°C、反应压力为16 MPa、氧化剂用量500 mg/L、反应停留时间为9 min,煤气废水的COD去除率达到了82.7%。采用正交设计试验的结果表明:反应温度是影响煤气废水中污染物处理效果的最关键因素。在湿式氧化处理煤气废水的效果和能力研究中发现,煤气废水经过湿式氧化处理后,取出液的可生化性在氧化作用下得到明显的增强。随着反应体系温度的不断提高,煤气废水流出液的可生化性已经变得越来越好。在反应温度达到310°C时,煤气废水流出液的BOD5/COD值远远大于0.45,此时可生化性表现最好。催化湿式氧化技术能在较低温度和压力条件下提高污染物的去除率。论文在研究的过程中发现:碱、过渡金属离子催化剂在湿式氧化技术处理煤气废水过程中表现出了很好的催化性能和活性。试验结果表明,少量的KOH、K_2CO_3和KHCO_3的加入有利于煤气废水中COD的有效去除,添加KOH比KHCO_3和K_2CO_3的COD去除率更高;KOH的最合适质量浓度为400 mg/L,此时煤气废水COD去除率可达到最大值88.7%。金属离子催化剂对湿式氧化煤气废水具有较好的催化活性。各种金属盐催化剂的催化活性由高到低的顺序为:Fe_2(SO_4)_3NiSO_4MnSO_4。随着反应停留时间的不断延长,在Fe~(3+)和Ni2+催化剂的催化作用下,煤气废水的COD去除率逐渐的提高。到反应停留时间为9 min时,Fe_2(SO_4)_3和NiSO_4催化下的COD去除率分别为99.5%和97.3%。为了更好的考察各个影响因素之间的关系,采用中心组合设计,实验结果表明,反应压力、反应温度、反应停留时间、氧化剂用量等对COD去除率的影响都比较大,温度对COD去除率的影响最大。
[Abstract]:Because gas wastewater contains a large amount of organic pollutants and high concentration of ammonia nitrogen, these pollutants are difficult to be treated by biodegradation, resulting in the effluent is very difficult to meet the discharge requirements and standards, and need to be advanced treatment and disposal. Advanced oxidation is one of the main methods for removing refractory organic matter from wastewater, so it has been widely used in water treatment. This paper deals with the advanced treatment of gas wastewater by wet oxidation method, and studies the degradation characteristics and reaction mechanism of gas wastewater in wet oxidation reaction system, which provides effective guidance and useful reference for the treatment of gas wastewater at high temperature and high pressure. The main influence parameters such as reaction pressure, reaction temperature, reaction residence time, oxidant dosage and so on in the treatment of gas wastewater by wet air oxidation were investigated. Wet air oxidation technology shows good oxidation efficiency and treatment ability in the process of reaction. The optimal removal conditions were obtained as follows: reaction temperature 310 掳C, reaction pressure 16 MPA, oxidant dosage 500 mg / L, reaction residence time 9 min, COD removal rate of gas wastewater reached 82.7%. The results of orthogonal design showed that reaction temperature was the most important factor affecting the treatment effect of pollutants in gas wastewater. In the study of the effect and ability of wet air oxidation treatment of gas wastewater, it is found that the biodegradability of gas wastewater after wet air oxidation treatment is obviously enhanced under the action of oxidation. With the increasing of reaction temperature, the biodegradability of gas wastewater effluent has become better and better. When the reaction temperature reaches 310 掳C, the BOD5/COD value of the gas wastewater effluent is far greater than 0.45, and the biodegradability is the best. Catalytic wet air oxidation can improve the removal rate of pollutants at lower temperature and pressure. In this paper, it is found that alkali and transition metal ion catalysts have good catalytic performance and activity in the treatment of gas wastewater by wet air oxidation. The experimental results show that the addition of a small amount of Kohk K2CO3 and KHCO_3 is beneficial to the effective removal of COD in the gas wastewater. The most suitable mass concentration of Koh is 400 mg / L when the addition of KOH is higher than that of KHCO_3 and K_2CO_3, and the COD removal rate of the gas wastewater can reach the maximum value of 88.7b / L. Metal ion catalyst has good catalytic activity for wet oxidation gas wastewater. The order of catalytic activity of various metal salt catalysts from high to low is: SO_4 (SO_4) 3NiSO4MnSO4s. With the prolongation of residence time, the removal rate of COD from gas wastewater increases gradually under the catalysis of Fe3 and Ni2 catalyst. When the residence time of the reaction is 9 min, the removal rates of COD under the catalysis of SO_4 and NiSO_4 are 99.5% and 97.3%, respectively. In order to better investigate the relationship between various factors, the central combination design is adopted. The experimental results show that the reaction pressure, reaction temperature, reaction residence time and the amount of oxidant have great influence on the removal rate of COD. The effect of temperature on the removal rate of COD is the greatest.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X784

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