Provided herein are molecular sieve membranes for separating hydrocarbons of a lube feed stock into a permeate and a retentate based on molecular shape. The molecular sieve membranes comprise one or more layers of size-selective catalyst and a porous support comprising a plurality of diffusing gaps. Each layer of size-selective catalyst has a plurality of perpendicular membrane channels and a plurality of opening pores. The porous support is in fluidic communication with the plurality of opening pores to provide a fluidic pathway between the perpendicular membrane channels and the diffusing gaps. Also provided are processes for separating n-paraffins from other hydrocarbons in a lube feed stock using the present molecular sieve membranes.

Systems and methods are provided for performing solvent dewaxing using a dewaxing solvent that is not fully miscible with the feed being dewaxed. It has been unexpectedly discovered that by operating with a ketone solvent mixture that is beyond the miscibility limit by a small amount, the rate of solvent dewaxing can be substantially increased. Additionally, the difference between the filtration temperature during solvent dewaxing and the pour point of the resulting dewaxed product is unexpectedly reduced. The dewaxing solvent beyond the miscibility limit can correspond to, for example, a solvent mixture where the weight percent of methyl ethyl ketone is beyond the miscibility limit by 0.1 vol % to 5.0 vol %.

Systems and methods are provided for performing solvent dewaxing using a dewaxing solvent that is not fully miscible with the feed being dewaxed. It has been unexpectedly discovered that by operating with a ketone solvent mixture that is beyond the miscibility limit by a small amount, the rate of solvent dewaxing can be substantially increased. Additionally, the difference between the filtration temperature during solvent dewaxing and the pour point of the resulting dewaxed product is unexpectedly reduced. The dewaxing solvent beyond the miscibility limit can correspond to, for example, a solvent mixture where the weight percent of methyl ethyl ketone is beyond the miscibility limit by 0.1 vol % to 5.0 vol %.

Recycling of exhausted wax in a process of lost wax micro casting.

Provided herein are molecular sieve membranes for separating hydrocarbons of a lube feed stock into a permeate and a retentate based on molecular shape. The molecular sieve membranes comprise one or more layers of size-selective catalyst and a porous support comprising a plurality of diffusing gaps. Each layer of size-selective catalyst has a plurality of perpendicular membrane channels and a plurality of opening pores. The porous support is in fluidic communication with the plurality of opening pores to provide a fluidic pathway between the perpendicular membrane channels and the diffusing gaps. Also provided are processes for separating n-paraffins from other hydrocarbons in a lube feed stock using the present molecular sieve membranes.

A method for dewaxing of an extract oil and a rubber oil is provided, where a composite solvent including a polar solvent and a solubilizer is used as a dewaxing solvent, the polar solvent is N-methylpyrrolidone (NMP), and the solubilizer is at least one selected from the group consisting of benzene, toluene, and xylene. The method includes: mixing the composite solvent with the extract oil or the rubber oil at a temperature higher than a precipitation temperature of a wax, subjecting a resulting mixture to cooling crystallization and filtration to obtain a wax paste and a filtrate, and then independently subjecting the wax paste and the filtrate to solvent recovery by heating evaporation to obtain a wax and a dewaxed oil, respectively.