重质油梯级分离新工艺的工程基础研究

Engineering basics of heavy oil deep stage separating process

利用自行开发的重质油超临界精密分离新方法对国内外多种重质油进行分析,结果表明重质油超临界精细分离窄馏分的重要物理和化学性质随溶解度(分离收率)的增加而变化,通过萃取可以使重质油中的重金属、沥青质等浓缩在萃取残渣中,而萃取馏分性质得到明显改善,据此提出了'重质油梯级分离'新工艺。为此在1kg.h-1及10kg.h-1连续式溶剂梯级分离实验装置上,以戊烷C5为溶剂,进行了大港减渣及辽河减渣的深度梯级分离脱除残渣的实验室研究和中试研究,考察了溶剂比、温度、压力等因素对脱残渣油收率和性质的影响规律。得到了超临界萃取的优化工艺参数:萃取温度160～170℃,一、二段温差5～15℃;萃取压力4.0～5.0MPa;溶剂比4.0～4.5(质量比)。确定了合适的超临界回收条件:温度200～220℃,压力4.0～4.5MPa,可使溶剂和油得到有效的分离。根据萃取塔底所处的温度、压力条件及物料组成,创造性地提出了利用超临界条件下喷雾造粒技术,实现了硬沥青喷雾造粒并与萃取过程的耦合,并对硬沥青颗粒流化与输送性能进行了研究。研究结果为'重质油梯级分离'新工艺的工业放大奠定了工程基础。

A number of vacuum residua（VR）in China and abroad were separated by using supercritical fluid extraction and fractionation technology（SFEF）.It is showed that the properties of the obtained narrow cuts depend on the solvent solubility,by which the asphaltene and metals are enriched in the unextractable endcuts and thus the properties of extract cuts greatly improved.A new process of heavy oil deep stage separation is put forward based on the discovery.Research on deep stage separation of Dagang VR and Liaohe VR was carried out on 1 kg·h-1 and 10 kg·h-1 capacity unit with n-pentane as solvent.Effects of solvent to feed ratio S/O,temperature and pressure on the yield and the properties of the deasphated oil（DAO）were investigated and the optimized process parameters were determined as following：extraction temperature within 160—170 ℃,pressure 4.0—5.0 MPa and S/O（mass ratio）4.0—4.5.The appropriate supercritical solvent recovery conditions were determined in range of temperature of 200—220℃ and pressure 4.0—4.5 MPa.The novel aspect is that deoiled asphalt（DOA）are discharged as fine particles by coupling the supercritical extraction and spraying granulation.The fluidization properties of the DOA powders were measured also for transportation purpose.The results provide the basis for industrial scale-up of the heavy oil deep stage separation.