Recovery Of Ionic Liquids From The Wastes Generated From The Hybrid Solvent Extraction Of Oil Sands

As a kind of unconventional oil energy resources,oil sands have attracted extensive attention both at home and abroad.As a potential technology,solvent extraction has many advantages,such as high extraction rate,wide adaptability and water saving.However,in the solvent extraction process,there is a higher amount of mineral residue entrainment in the liquid phase,and the extraction efficiency is also greatly affected by the solvent.In order to solve these problems,many researchers used ionic liquids to enhance organic solvent extraction of bitumen from oil sands.Under the same solvent conditions,this process not only improved the extraction rate,but also improved the quality of extraction products and reduced solid entrainment.However,the process involved the loss of ionic liquids due to the presence of ionic liquids remaining in solid residues.In order to solve the problem of ionic liquid recovery from solid residues in the process of ionic liquid assisted solvent extraction,a method of water washing-ion exchange was proposed for the recovery of ionic liquids.Based on the isotherms,thermodynamics and kinetics of adsorption process,we studied the absorption of ionic liquid from aqueous solution by ion-exchange resin.Finally,the recovery of ionic liquids from the wastes generated from the hybrid solvent extraction of oil sands was optimized.The results showed that the ionic liquid in the residual sand can be transferred to the aqueous solution by water washing.The optimum concentration of ionic liquid in the solution was 12¹5mg/mL after washing.Ionic liquids（[BMim]BF₄,[EMim]BF₄and[MMim]BF₄）from aqueous solution were concentrated and recycled using the ion-exchange resins mothod.The experimental results showed that the adsorption of ionic liquids from aqueous solution accorded with D-R isothermal adsorption model and pseudo-first-order model and the absorption mechanisms included ion exchange which played a dominant role and physical adsorption.Through the parameter optimization experiment,the optimum process conditions of ionic liquid adsorption were:resin:IL=10:3（g/g）,at 293K for the adsorption and adsorption in 15min.The efficiencies of adsorption was over 96%.The ionic liquid adsorbed on the resin was desorbed to recover the ionic liquid.And the optimum desorption temperature was333K and the optimum concentration of hydrochloric acid desorption agent was 15%.The efficiencies of desorption and recovery were over 92%and 91%,respectively and this process could save energy by 42%compared with the direct distillation under laboratory conditions.