环境响应性纳米催化剂的制备及其对稠油催化降粘的作用机制

The natural resource distribution of heavy crude oils in China is wide, and their reservations are rich. However, the technical recovery ratio of the heavy crude oils is only 13% due to the limition of the production technique. The key role to improve the recovery ratio is to decrease the viscosity of the heavy oils, and improve the fluxility. The viscosity reduction of heavy oils by the catalytic aquathermolysis method is one of the most efficient ways.The water-soluble catalyst is hard to contact with the heavy oils, so the yield of the viscosity reduction is low. On the other hand, the yield of the oil-soluble catalyst is high, but this method needs to consume a lot of organic carrier solvents. In this project, the metal nanocatalysts (Ni, Fe, Co, their binary alloys, and a spot of Pt, Rh loading) will be supported on the surface of highly active functional supports (anometer polysilicon, montmorillonoid, or molecular sieves). Through the surface modification by differnt orangic dressing agent, this nanocatalyst can form to microemulsion and become dispersedly stable in water, so they can enter to the micropores of the heavy oil deposit with different porosity. And the emulsion breaking can be realized when the environment (temperature, pressure, and mineralization of water) of the mimic oil deposit is applied, which can lead the supported catalyst transfer to the oil phase. That will increase the efficient contaction between the catalyst and the target heavy oils, and realize the catalytic irreversible reduction of the viscosity. The gather, dispersion of the supported catalysts on the interface of the oil and water will be systematically investigated, and their effect on the viscosity reduction yield and the catalytic mechanism will be studied in detail.This project will have the important research value for designing the efficiently practical catalysts and improving the recovery ratio of the heavy crude oils.

我国稠油资源分布广泛、储量丰富，但是目前技术可采率仅有13%。降低稠油粘度、提高流动性是其高效开采的技术关键。水热催化降粘是当前最受关注的方法之一。但是常见的水溶性催化剂与稠油难接触、效率低；油溶性催化剂需耗费大量的有机携带剂。 本项目拟将纳米金属催化剂(Ni、Fe、Co、二元合金及负载微量的Pt、Rh)担载于高活性的功能载体（纳米聚硅、蒙脱土、分子筛等）上，通过表面修饰技术实现其在廉价水携带体系中的稳定分散；利用油藏储层特有的物理化学环境（低温、高压、高矿化度等）诱导其向油相转移，提高与稠油分子的高效接触，实现不可逆降粘。通过系统研究该环境响应性催化剂在油/水界面的聚集、分散状态，掌握其水分散-相转移规律；通过对稠油流变特性和组学变化的影响，阐明催化剂对稠油降粘的作用机制。该项目对设计实用高效型的催化降粘剂和提高稠油采收率具有重要的研究价值。

石油是一种不可再生资源，随着能源消耗的日益增长，传统的轻质原油日渐枯竭，稠油作为一种特殊的石油资源因其储量大、分布广，受到广泛关注。但稠油粘度高，流动性差，造成其开采及运输困难。解决稠油开采的关键技术是降低粘度、提高流动性。本项目从催化、乳化两方面入手，设计了系列功能性催化剂和乳化剂，以胜利油田超稠油为应用体系，对降粘效果和作用机制进行了系统研究。稠油水热催化降粘反应的效率强烈依赖于催化剂与稠油的接触反应程度。常规的无机催化剂难于在稠油中均匀分散，催化效率受到一定的限制。（1）分别采用高温煅烧法、溶剂热法制备的二维碳材料（石墨烯、多孔碳层等）负载纳米金属（铁、镍等）复合材料具有较大的比表面积，可提升与稠油的接触，有利于稠油的催化裂解；同时铁、镍纳米颗粒表面也能够提供更多的催化活性位点。利用水热法制备的SiO2/H2TiO3固体超强酸可以实现催化剂由水相向油相的转移，提高催化剂在油相中的分散性。（2）SO42-/ZrO2-TiO2超强酸催化剂经十六烷基三甲基溴化铵修饰后分散性得以显著提高，对稠油的降粘作用增强。在超强酸催化剂基础上构建的ZSM-5-ZrSi分子筛超强酸，相比于无分子筛结构的超强酸及ZrSi分子筛，在稠油催化降粘中表现出更加优异的性能。（3）采用一步法制备了钼掺杂β-FeOOH纳米棒，在供氢体四氢萘辅助下显著提高了超稠油的降粘率。催化剂促进了C-S键的断裂，而四氢萘能有效抑制小分子的再聚合。（4）对于合成的系列油溶性催化剂（油酸铁、油酸钴、油酸镍），油酸铁性能最佳。（5）利用聚乙烯亚胺（PEI）与溴苄反应制备了双亲性可控的PEI基聚合物，其对超稠油表现出优异的乳化降粘效果，降粘率达99.9%以上，乳液粘度低至100 mPa·s以下，可达到管道运输的要求，归因于在乳化剂作用下形成了稳定的水包油(O/W)型乳液。