超临界水在重油加工中的研究进展

超临界水作为一种对环境友好并且对轻烃组分具有良好溶解扩散能力的优良溶剂,在重油改质过程中有广泛应用。超临界水的引入不仅可以达到强化传质的目的,对热裂化机理产生影响,而且可以改变反应过程中体系的相结构,促使体系相行为从液-液两相向微乳体系甚至是拟均相转变,为开发新的重油加工工艺提供了可能。本文首先介绍了超临界水的基本性质,着重介绍了超临界水参与下重油的改质机理、反应过程中的裂化动力学以及改质过程中相行为的变化,发现在高水密度、剧烈搅拌和高水油比的条件下重油-超临界水表现出拟均相行为,能够达到改善液收、降低黏度并且减少生焦的目的。最后对超临界水处理重油的发展前景和方向进行了展望。

Recent advances in supercritical water treatment of heavy oil

As an environmentally solvent, supercritical water (SCH₂O) has excellent dissolution and diffusion ability for light hydrocarbon components and can be used as a reaction medium in upgrading process of heavy oil. The introduction of SCH₂O can not only strength the mass transfer, but also affect the mechanism of cracking reaction, even promote the phase behavior from liquid-liquid to the condensed emulsion or pseudo single-phase, which provides a possibility for developing new heavy oil processing technology. This paper reviewed the basic property of SCH₂O. Meanwhile, the reforming mechanism of heavy oil upgrading with supercritical water, the cracking kinetics and the transfer of phase behavior during the reaction were emphatically discussed. It was found that the pseudo single-phase of heavy oil and supercritical water can be formed under the conditions of high temperature, high pressure, vigorous stirring and high water-oil ratio which can increase conversion, decrease the viscosity and reduce coke filed. Finally, the SCH₂O development prospect and direction of SCH₂O treatment of heavy oil were outlined.