摘要:
A dewaxing process is described comprising contacting a waxy lubricating oil with a dewaxing solvent in a chilling zone divided into a plurality of stages. The dewaxing solvent is injected into the chilling zone under conditions such that the solvent and oil are immiscible at the point of injection. At least a portion of the wax is precipitated from the oil and is separated therefrom under conditions such that the solvent and oil are miscible. Solvent injection is at a temperature preferably below 0*F. when the solvent comprises 40 volume percent methylethylketone and 60 volume percent methylisobutylketone.
摘要:
A dewaxing process is described wherein a residual waxy petroleum oil stock characterized by having a viscosity greater than about 75 SUS at 210*F. and containing less than about 10 percent of material boiling below about 950*F., is mixed with at least about 0.3 volumes of a dewaxing solvent per volume of residual waxy oil stock, thereby depressing the cloud point of same. In one embodiment of the invention, the resultant mixture is introduced into a cooling zone, at a temperature above the depressed cloud point of the oil. Precooled dewaxing solvent is incrementally added to the cooling zone which is divided into a plurality of stages with agitation means present in each of the stages. The resultant solvent-oil mixture is cooled and agitated as it passes through the cooling zone, thereby reducing the temperature of the oil to below its depressed cloud point and precipitating at least a portion of the wax therefrom. A residual oil stock of diminished wax content is thereafter recovered. In a second embodiment of the invention, the waxy oil stock is introduced into the cooling zone in the absence of solvent at a temperature above the cloud point of the oil. Precooled dewaxing solvent is introduced incrementally into the initial stages of the cooling zone, coming into contact with the waxy oil and depressing its cloud point. The oil is gradually cooled to a temperature no less than the depressed cloud point of the oil whereupon additional precooled dewaxing solvent is added to the oil in the remaining stages of the cooling zone, thereby gradually cooling the oil to a temperature below the depressed cloud point and precipitating at least a portion of the wax therefrom.
摘要:
IN A PROCESS FOR THE SEPARATION AND REMOVAL OF WAX FROM PETROLEUM HYDROGACBON OILS SUCH AS DISTILLATES, RESIDUAL BRIGHT STOCKS AND THE LIKE, BY DISSOLVING THE OIL IN A DEWAXING SOLVENT OR MIXTURE OF SLVENTS, CHILLING THE SOLUTION TO CRYSTALLIZE OR PRECIPITATE THE WAX, SEPARATING THE EDWXED OIL SOLUTION FROM THE WAX AS BY CENTRIFUGATION OR FILTRATION AND RECOVERING A SOLVENT-FREEE OIL AND WAX, THE IMPROVEMENT COMPRISING: THE INCORPORATION INTO THE OIL OR OIL-SOLVENT MIXTURE PRIOR TO OR DURING THE CHILLING OPERATION OF A MIXTURE OF: (A) AT LEAST TWO DIFFERENT ZIEGLER-NATTA CATALYZED LONG CHAIN OLEFINS HOMOPOLYMERS, OR AN INTERPOLYMER COMPRISING AT LEAST TWO DIFFERENT LONG CHAINS OLEFINS, SAID OLEFINS BEING C14 TO C24 "SUBSTANTAILLY LINEAR" ALPHA-MONO-OLEFINS OR MIXTURES THEREOF AND (B) A HOMOPOLYMER OR INTERPOLYMER OF ONE OR MORE C10 TO C24 N-ALKYL ESTERS OF METHACRYLIC ACID. USE OF THE MIXTURE OF THE DEWAXING AIDS (A) AND (B) CAN RESULT IN THE FORMATION OF A WAX CRYSTAL THAT FILTERS MORE RAPIDLY AND RETAINS LESS OIL THAN WHEN EITHER COMPONENT OF THE MIXTURE IS USED ALONE AT COMPATABLE CONCENTRATIONS.
摘要:
Lubricating oil fractions are dewaxed by contacting them with successive increments of cold solvent at a plurality of points along a vertical tower while maintaining a zone of intense agitation at each point of solvent injection so that substantially instantaneous mixing occurs at each point, continuing the chilling by means of cold solvent injection until a temperature greater than the filtering temperature but less than about 35*F. above the filtering temperature is reached and completing the cooling of the oil to the separation temperature in a scraped-surface cooler.