Polyvinyl alcohol is a refractory compound widely used in industry. Here we report supercritical water oxidation of polyvinyl alcohol solution and desizing wastewater with and without sodium hydroxide addition. However, it is difficult to implement complete degradation of organics even though polyvinyl alcohol can readily crack under supercritical water treatment. Sodium hydroxide had a significant catalytic effect during the supercritical water oxidation of polyvinyl alcohol. It appears that the OH ion participated in the C-C bond cleavage of polyvinyl alcohol molecules, the CO2-capture reaction and the neutralization of intermediate organic acids, promoting the overall reactions moving in the forward direction. Acetaldehyde was a typical intermediate product during reaction. For supercritical water oxidation of desizing wastewater, a high destruction rate (98.25%) based on total organic carbon was achieved. In addition, cases where initial wastewater was alkaline were favorable for supercritical water oxidation treatment, but salt precipitation and blockage issues arising during the process need to be taken into account seriously.
Jie ZhangShuzhong WangYang GuoDonghai XuYanmeng GongXingying Tang
对煤的超临界水氧化(Supercritical Water Oxidation,SCWO)技术进行综述,介绍了煤颗粒在超临界水中的点火模型和最新的反应动力学研究,分析了煤中硫、氮等元素变迁路径。从理论层面讨论了煤的SCWO过程能量的利用方法,归纳了SCWO过程中反应系统、单个组件效率计算方程。最后,提出了尚需解决的科学问题。
