Method and apparatus for high pressure fractional crystallization

Claim 1

IN THE METHOD OF FRACTIONAL CRYSTALLIZATION WHEREIN A FRESH FEED LIQUID CONTAINING A MATERIAL TO BE SEPARATED THEREFROM BY FRACTIONAL CRYSTALLIZATION IS SUBJECTED TO AN ELEVATED PRESSURE OF AT LEAST 2000 P.S.I.G. WITHIN A HIGH PRESSURE FRACTIONAL CRYSTALLIZATION ZONE TO EFFECT CRYSTALLIZATION OF SAID MATERIAL, THE IMPROVEMENT WHICH COMPRISES RECOVERING FROM SAID HIGH PRESSURE FRACTIONAL CRYSTALLIZATION ZONE A SPENT LIQUID HAVING A REDUCED PROPORTION OF SAID MATERIAL WITH RESPECT TO SAID FRESH FEED LIQUID AT A PRESSURE SOMEWHAT LOWER THAN THE PRESSURE MAINTAINED IN SAID HIGH PRESSURE CRYSTALLIZATION ZONE, INTRODUCING SAID SPENT LIQUID INTO A PRESSURE TRANSFER ZONE FILLED WITH A PRESSURE TRANSFER LIQUID SAID PRESSURE TRANSFER LIQUID BEING SUBSTANTIALLY IMMISCIBLE WITH AND MORE DENSE THAN SAID FRESH FEED LIQUID AND SAID SPENT LIQUID, WHEREBY SAID PRESSURE TRANSFER LIQUID IS PRESSURIZED BY DIRECT CONTACT WITH SAID SPENT LIQUID TO SUBSTANTIALLY THE SAME PRESSURE AS SAID SPENT LIQUID, PRESSURIZING ADDITIONAL FRESH FEED LIQUID WITH SAID PRESSURIZED TRANSFER LIQUID BY DIRECT CONTACT THEREWITH, THEN RAISING THE SO PRESSURIZED ADDITIONAL FRESH FEED LIQUID AT LEAST TO THE ELEVATED PRESSURE OF SAID FRACTIONAL CRYSTALLIZATION ZONE, AND THEN INTRODUCING SAID ADDITIONAL FRESH FEED LIQUID INTO SAID HIGH PRESSURE FRACTIONAL CRYSTALLIZATION ZONE WHEREBY AT LEAST PART OF THE ENERGY IN SAID SPENT LIQUID IS RECOVERED.