双功能金属纳米晶/水合肼体系催化稠油原位裂解加氢降黏改质

催化裂解加氢技术在高温条件下使稠油大分子催化裂解，并通过加氢提高产物的氢/碳比，从而降低稠油黏度，提高产物轻质化程度。采用液相还原法制备了Ni、Pd及Ni-Pd合金纳米晶催化剂，并采用水合肼(N2H4·H2O)作为供氢剂，对南堡油田稠油进行催化裂解加氢降黏研究。利用永磁旋转搅拌高压釜模拟地层条件，通过正交实验确定了最佳反应条件并利用HSC Chemistry软件分析了供氢剂的热力学性质，在最佳反应条件下进行对比实验。结果表明：金属纳米晶可促进稠油大分子裂解并使供氢剂分解释氢，其中钯纳米晶/水合肼体系对稠油的降黏效果最好。与原油样品相比，改质后油样重质组分质量分数减少8.34百分点，降黏率达到91.3%。根据文献对稠油黏度降低的可能机理进行了简要分析。改质后的稠油黏度显著降低，可为稠油有效开采提高采收率提供理论参考。

In-Situ Viscosity Reduction for Heavy Oil ThroughCatalytic Hydrocracking with Bifunctional Metal Nanocrystals/Hydrazine Hydrate System

Catalytic hydrocracking technology enable long chain macromolecule in heavy oils cracking at high temperatures, and thus results in higher H/C atomic ratio, less viscosity and more light products. In this work, Ni, Pd and Ni-Pd alloy metal nanocrystal catalysts were prepared through one-pot wet chemical route, and hydrazine hydrate (N2H4·H2O) was used as hydrogen donor to study in-situ viscosity reduction of Nanpu heavy oil by hydrocracking method. The stratum conditions were simulated by a high pressure autoclave with a magnetic stirrer, and the optimal reaction conditions were investigated by the orthogonal test method. In addition, thermodynamic properties of the hydrogen donor were also analyzed with the HSC chemistry software, and comparison experiments were performed under the optimal reaction conditions. Experimental results indicate that metal nanocrystals can enhance catalytic cracking reactions of macromolecules in the heavy oil and also promote hydrogen donor to release hydrogen. It is found that Pd nanocrystals/hydrazine hydrate system exhibits the best heavy oil viscosity reduction performance. After catalytic hydrogenation, the mass fraction of heavy components decreased by 8.34 percentage point, and the viscosity reduction rate can be up to 91.3%. Possible viscosity reduction mechanisms were also analyzed based on literature review. The viscosity of heavy oils after hydrotreating can be significantly reduced, and the proposed method can provide theoretical guidance for heavy oil enhanced oil recovery development.