委内瑞拉超重原油和加拿大油砂沥青加工现状及发展前景

Current Status and Development Prospects for Processing of Venezuelan Extra-heavy Crude and Canadian Oil Sand Bitumen

委内瑞拉超重原油和加拿大油砂沥青都是高密度、高黏度、高硫、高氮、高酸、高残炭、高金属、高沥青质的劣质原油,不仅重馏分油和渣油中的金属含量高,而且轻馏分油中的金属含量也比较高,是当今世界上最难加工的原油。除了难以开采和开采成本高以外,对于炼厂还存在难以输送、难以脱盐脱水、难以正常生产运行等问题。炼厂加工高硫高酸超重原油或油砂沥青生产清洁燃料和裂解料难度很大:一是常压直馏馏分油太少;二是减压瓦斯油和减压渣油太多;三是常减压蒸馏各直馏馏分中硫含量和酸值都比较高,都需要深度精制或加工。而利用好高硫高酸超重原油和油砂沥青的减压渣油是用好非常规石油资源,提高轻油收率的关键所在。目前世界上只有委内瑞拉4座加工奥里诺科超重原油和加拿大6座加工油砂沥青的改质工厂在生产,产品为合成原油。正在建设中的加工委内瑞拉超重原油的炼油厂有4座,计划建设的油砂沥青炼油厂只有1座。加拿大油砂沥青改质工厂的技术和生产水平都比委内瑞拉超重原油改质工厂高一些。我国三大石油公司与委内瑞拉和加拿大的合作都取得了很大进展,在我国炼油厂大量加工委内瑞拉超重原油已指日可待,预计我国炼油厂加工加拿大油砂沥青也为时不远。为此,建议有关科研项目应抓紧工作,尽早提出研究成果和关键技术问题的解决方案;同时着手开展相关技术,特别是减压渣油悬浮床加氢裂化技术的开发工作;跟踪国外有关加工技术研发的工作进展,为我国的消化、吸收、再创新打好基础。

Both Venezuelan extra-heavy oil and Canadian oil sand bitumen are inferior-quality crude oils with high density,high viscosity,and high sulfur,nitrogen,acid,residual carbon,metal and asphaltene contents.The content of metals is high not only in heavy distillates and residuum but also in light distillates,making these crudes the most difficult to process worldwide.In addition to the difficulty in recovery and the high cost of production,for a refinery,these crudes are also difficult to transport,to desalt,to dehydrate and to process.It is actually a great challenge to refineries to process high-sulfur,high-acid and extra-heavy crude or oil sand bitumen to produce clean fuels and cracking materials.This is due to three factors: firstly,the share of atmospheric straight-run distillates is too low;secondly,the shares of vacuum gas oil and vacuum residuum are too high;and thirdly,both sulfur content and acidic value are high in the straight-run distillates in atmospheric and vacuum distillation,thus requiring deep refining or processing.Making a good use of the vacuum residuum from high-sulfur,high-acid and extra-heavy crude oil and oil sand bitumen is the key to well utilizing unconventional oil resources and raising the yields of light oil products.To date,worldwide only four refineries in Venezuela are processing extra-heavy Orinoco crude oil and six Canadian refineries are processing oil sand bitumen to produce synthetic crude oil.Additional four refineries designed to process Orinoco oil are under construction and there is only one refinery being planned for processing oil sand bitumen.Canada′s oil sand bitumen modifying plants are superior to Venezuela′s extra-heavy oil modifying plants in terms of both technical and production capabilities.China′s Big Three national companies have made important progress in investing in both Venezuela and Canada.Chinese refineries will soon start processing Venezuelan extra-heavy oil on a large scale and will also start processing Canadian oil sand bitumen in the not-too-distant future.Therefore,we suggest quickening the construction of relevant research programs to bring up research results and solutions to key technological issues as soon as possible.China should also embark on the development of relevant technologies,particularly vacuum residuum suspended bed hydrocracking techniques,and track the process in processing technology research and development in foreign countries to lay the groundwork for the acquisition and assimilation of foreign technologies as well as innovations.