Supercritical Water Oxidation is a promising technology to deal with the phenolic-benzoic nature of the wastewater from Propylene Oxide-Styrene Monomer processes. To assess its feasibility to meet discharge regulations for a continuous process, lab-scale assays were conducted with real wastewater. After a screening to maximize Chemical Oxygen Demand (COD) removal efficiency, a supercritical, four-hour duration test was run at 550 °C, 235 bar g, with 50% excess oxygen and residence time of 120 seconds. Though a successful COD degradation of 99.97 ± 0.01% was achieved, salt scaling and corrosion occurred. The key findings are that to redissolve salts and avoid corrosion, focus must be on the supercritical to subcritical transition location. Near-supercritical oxidation was also tested as a cost-effective alternative to avoid scaling. Residence times up to 192 min were required at 300 °C, 165 bar g and 40% excess oxygen to achieve similar degradation obtained to supercritical conditions.

中文翻译：

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用于处理环氧丙烷-苯乙烯单体 (POSM) 废水的小规模超临界和近超临界水氧化测定

超临界水氧化是处理环氧丙烷-苯乙烯单体工艺废水中酚苯甲酸性质的一项很有前途的技术。为了评估其满足连续工艺排放法规的可行性，对真实废水进行了实验室规模的测定。经过筛选以最大限度地提高化学需氧量 (COD) 去除效率后，在 550 °C、235 bar g、过量氧气 50% 和停留时间 120 秒的条件下进行了持续四小时的超临界测试。尽管成功实现了 COD 降解率 99.97 ± 0.01%，但还是出现了盐垢和腐蚀。主要发现是，为了重新溶解盐并避免腐蚀，重点必须放在超临界到亚临界的转变位置。还测试了近超临界氧化作为避免结垢的经济有效的替代方案。在 300 °C、165 bar g 和 40% 过量氧气下，需要长达 192 分钟的停留时间才能实现与超临界条件类似的降解。