Abstract:
Oil refineries produce annually large quantities of oily sludge and non-biodegradable wastewater during petroleum refining that require adequate management to minimize its environmental impact. The fraction solid of the oily sludge accounts for 25 wt% and without treatment for their valorization. This work is focused on the valorization of these solid particles through their transformation into porous materials with enhanced properties and with potential application in the catalytic wet air oxidation (CWAO) of a non-biodegradable spent caustic refinery wastewater. Hence, dealing with the valorization and treatment of both refinery wastes in a circular approach aligned with the petrol refinery transformations by 2050. The obtained oily sludge carbonaceous materials showed improved surface area (260-762 m2/g) and a high Fe content. The good catalytic performance of these materials in CWAO processes has been attributed to the simultaneous presence of surface basic sites and iron species. Those materials with higher content of Fe and basic sites yielded the highest degradation of organic compounds present in the spent caustic refinery wastewater. In particular, the best-performing material ACT-NP 1.1 (non-preoxidated and thermically treated with 1:1 mass ratio KOH:solid) showed a chemical oxygen demand (COD) removal of 60 % after 3 h of reaction and with a higher degradation rate than that achieved with thermal oxidation without catalyst (WAO) and that using an iron-free commercial activated carbon. Moreover, the biodegradability of the treated wastewater increased up to 80% (from ca. 31% initially of the untreated effluent). Finally, this material was reused up to three catalytic cycles without losing metal species and keeping the catalytic performance.
摘要:
炼油厂在石油精炼过程中每年产生大量含油污泥和不可生物降解的废水,需要适当的管理以最大程度地减少其对环境的影响。含油污泥的固体分数占25wt%,并且未经处理其价值。这项工作的重点是通过将这些固体颗粒转化为具有增强性能的多孔材料,并在不可生物降解的废苛性炼油厂废水的催化湿式空气氧化(CWAO)中具有潜在的应用。因此,到2050年,以与炼油厂改造相一致的循环方式处理两种炼油厂废物的价值化和处理。获得的含油污泥含碳材料显示出改善的表面积(260-762m2/g)和高的Fe含量。这些材料在CWAO工艺中的良好催化性能归因于同时存在表面碱性位点和铁物种。铁含量和碱性位点较高的那些材料对废苛性炼油厂废水中存在的有机化合物的降解最高。特别是,性能最佳的材料ACT-NP1.1(非预氧化和用1:1质量比KOH:固体进行热处理)反应3小时后,化学需氧量(COD)的去除率为60%,并且降解率高于没有催化剂(WAO)和使用无铁商业活性炭的热氧化。此外,处理后的废水的可生化性提高了80%(从大约最初是未经处理的流出物的31%)。最后,这种材料可重复使用多达三个催化循环,而不会损失金属物种并保持催化性能。