Abstract:

Oily sludge is widely produced in the process of petroleum exploitation, refining and application. The resource utilization and harmless treatment of oily sludge has always been a problem in the industry. Taking the heavy oily sludge residue after traditional water washing treatment as an example, this paper systematically studied oxidative degradation law and process enhancement mechanism of it using peroxymonosulfate-ferrate-FeS (PFI) oxidation system. The results showed that the PFI oxidation system could degrade oily sludge residue containing heavy oil components such as resins and asphaltenes and converted large-molecule organics into small-molecule organics. However, due to the adsorption of sludge solid particles in porous pores and other reasons, some heavy components would remain in the pores and were difficult to degrade. In addition, after PFI oxidation of oily sludge, the resulting solid surface would be covered with a thin layer of secondary product iron oxide, which prevented the oxidant molecules from further contacting the petroleum molecules, thereby reducing the oxidation effect or even stopping the oxidation process. The surface acidity control method could greatly dissolve the thin iron oxide layer to increase the chance of contact between the oxidant and the organic matter, thereby enhancing the degradation rate of the residual heavy oil organic matter.

Key words: iron oxide, oxidation, degradation, peroxymonosulfate, ferrate, ferrous sulfide

摘要：

含油污泥广泛产生于石油开采、炼制与使用过程中。对含油污泥进行资源化与无害化低碳处理一直是行业的难题。以传统水洗处理后的含重质油污泥残渣为例，本文系统研究了采用过一硫酸盐-高铁酸盐-FeS（PFI）氧化体系对其进行氧化降解的规律及过程强化机制。结果表明PFI氧化体系能够对含重质油组分（胶质、沥青质等）的油泥残渣进行降解，将大分子物质转化为小分子有机物。然而，由于油泥固相颗粒多孔孔道吸附等原因，会有一部分的重质组分残留于孔道内，难以降解去除。此外，油泥经PFI氧化后，所得固体表面会覆盖一层二次产物氧化铁薄层，阻碍氧化剂分子进一步与石油分子的接触，从而降低氧化效果甚至终止氧化过程。采用表面酸性调控方法可以大幅度溶解氧化铁薄层，增加氧化剂与有机物的接触机会，从而强化残留重质油有机物降解率。

关键词: 氧化铁, 氧化, 降解, 过一硫酸盐, 高铁酸盐, 硫化亚铁