Abstract: It has been discovered that (a) poly di alkyl fumarate/vinyl acetate copolymers in combination with (B) poly alkyl (meth-) acrylate polymers are effective dewaxing aids for the solvent dewaxing of bright stocks. The poly di alkyl fumarate/vinyl acetate copolymer component of the combination dewaxing aid used in the process of the present invention has a number average molecular weight of about 1000 to 100,000 and possesses alkyl side chain moieties of from C.sub.16 -C.sub.24.sup.+ in length (excluding branching) with a pendent side chain length of predominantly (>50%) C.sub.20. The polyalkyl (meth-) acrylate is the polymeric ester of aliphatic alcohols having groups 10 to 20 carbons in length, excluding branching (pendent side chain length predominantly (>50%) C.sub.14 and lower) and acrylic or (meth-) acrylic acid (preferably methacrylic acid) and possesses a number average molecular weight of at least 5,000.

Abstract: This invention relates to processes for solvent dewaxing bright stock waxy raffinate oil employing a dewaxing aid which dewaxing aid is a mixture of (a) poly di alkyl fumarate/vinyl acetate copolymers and (b) a wax-naphthalene condensate. The dewaxing aid mixture is a mixture of (a) poly di alkyl fumarate/vinyl acetate copolymer having a number average molecular weight of about 1,000 to 100,000, preferably 5,000 or greater, possessing alkyl side chain moieties of from C.sub.16 -C.sub.24+ in length (excluding branching) with an average pendent side chain length of predominantly (>50%) C.sub.20 and (b) a wax-naphthalene condensation product having a number average molecular weight of about 1,000 and greater. The combination (a) plus (b) may be employed in a weight ratio within the range from about 45/55 to 1/100, preferably about 1/3, and at an aid dose level ranging from about 0.005 to 2.0 wt %, preferably 0.01 to 0.2 wt % active ingredient.

Abstract: A warm-up deoiling process for lube oil slack wax wherein cold slack wax from a solvent dewaxing operation is warmed up and mixed with solvent to dissolve foots oil contained therein and passed to a rotary drum filter to recover solid wax and a filtrate comprising a solution of foots oil and solvent wherein said filtrate is contacted with one side of a semi-permeable membrane made from regenerated cellulose which selectivity permeates at least a portion of solvent through said membrane and recycling the permeated solvent directly back into the warm-up deoiling operation as part of the solvent mixed with the slack wax.

Abstract: Waxy oils are solvent refined in a relatively low temperature, combination extraction-dewaxing process wherein the waxy oil is simultaneously extracted and at least partially dewaxed in a dilution chilling zone, sequentially followed by a second extraction and a second dewaxing to produce wax and useful lube oils, and wherein solvent does not have to be removed from the oil as it passes from step to step of the process. Further, if the second dewaxing is performed in a dilution chilling zone, then scraped-surface chillers are not required prior to filtering the wax from the oil.

Abstract: A very low pour point transformer oil is produced by a process wherein a narrow cut distillate of a paraffinic crude from conventional crude oil atmospheric or vacuum towers is first solvent extracted to remove aromatics and polar components, followed by immiscible solvent dewaxing whereby two liquid and one solid phases form a wax-containing slurry which is filtered to produce a wax cake which contains a high viscosity index oil and a filtrate which contains a very low pour point transformer oil.

Abstract: A dewaxing process is described wherein a waxy petroleum oil stock such as residual or a broadcut feedstock, characterized by containing at least 10% of residual material boiling above about 1000.degree. F., is mixed with at least about 0.3 volumes of a dewaxing solvent per volume of 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. An oil stock of diminished wax content is thereafter recovered.