Abstract: A used lubricating oil comprising lube oil additives, including zinc dithiophosphate is reconstituted. Zinc dithiophosphate is thermally decomposed at a temperature of 400.degree. F. (204.degree. C.) to 1000.degree. F. (538.degree. C.) for a residence time of 10 to 120 minutes. The resulting oil is subjected to vacuum distillation. A zinc-free (i.e. ash free by ASTM D-482) oil is stabilized by catalytic hydrogenation or clay treating to produce a lubricating oil blending stock. About 5 to 25 vol % is recovered as a metal containing bottoms product, useful as asphalt extender. The process is carried out in the absence of chemical demetallizing.

Abstract: A used lubricating oil comprising lube oil additives, including zinc dithiophosphate is subjected to reclaiming. Zinc dithiophosphate is thermally decomposed at a temperature of 400.degree. F. (204.degree. C.) to 1000.degree. F. (538.degree. C.) for a residence time of 10 to 120 minutes. The resulting oil is subjected to vacuum distillation. A zinc-free (i.e. ash free by ASTM D-482) distillate oil is useful as marine diesel fuel. About 5 to 25 vol % is recovered as a metal containing bottoms product, useful as asphalt extender. The process is carried out in the absence of chemical demetallizing.

Abstract: The present invention is an automatic filter cleaning system which includes a solvent dewaxing filter which removes wax from a wax mix slurry and provides a filtrate. Status control apparatus is connected to the filter for affecting the operational status of the filter. Drain apparatus responsive to a control signal controls draining of the filter. Cleaning apparatus is also connected to the filter. A control network connected to the status apparatus, the draining apparatus and the cleaning apparatus controls those apparatus in a manner so as to allow selective changing of the status of the filter from an operational state to a down state to automatically drain the filter and clean the filter while the filter is in the down state.

Abstract: A control system controls a lubricating oil dewaxing apparatus. The temperature of waxy oil flowing through the apparatus is controlled. A sequential plurality of temperature sensing means senses the temperature of the waxy oil. A Comparing Means determines an isothermal heat transfer zone corresponding to latent heat transfer wax crystallization. Temperature upstream of the isothermal zone is controlled to a selected chilling rate. Temperature downstream of the isothermal zone is controlled to a selected filtering temperature. The control system effects the growth of wax crystals of a uniform and moderate size for optimum filtering rate and oil content.

Abstract: A process for dewaxing a petroleum oil stock with a liquid solvent employing direct heat exchange cooling of solvent-oil mixture with an immiscible liquid chilling medium.

Abstract: An improved method for solvent dewaxing oils in which a portion of the oil-solvent mixture is chilled to a temperature above its cloud point and a further portion is chilled to a temperature below its cloud point, the portions are combined to produce a mixture substantially at the cloud point, and the combined mixture further cooled to dewaxing temperature at which wax crystals are separated from the solvent and refined oil.

Abstract: A draw rate signal generator for an atmospheric crude distillation unit receiving crude oil and providing streams 1 through 5 and a reduced crude oil includes flow rate sensors sensing the flow rates of the crude oil and of streams 1 through 4 and providing corresponding signals. Analyzers sample the crude oil and provide signals corresponding to the 35% point temperature, the API gravity and the vapor pressure of the crude oil. End point analyzers sample streams Nos. 1 and 3 and provide signals representative of the end point temperatures of streams Nos. 1 and 3, respectively. 50% point analyzers sample streams 2, 3 and 4 and provide signals corresponding to the 50% point temperatures of streams Nos. 2, 3 and 4, respectively. A circuit connected to the sensors, to the crude analyzers, to the end point analyzers and to the 50% analyzers provide signals corresponding to the draw rates for streams Nos. 1 through 5 in accordance with signals from the sensors and analyzers.

Abstract: A solvent dewaxing process for removing wax from intermediate grade waxy petroleum distillate oils wherein a waxy oil stock, prediluted with 0-2 volumes dewaxing solvent is heated to a temperature in the range of about 110 to 130.degree. F for melting all wax therein; wherein the heated waxy oil stock/solvent mixture is cooled to about 5.degree. F above the depressed cloud point and is diluted with 1-5 volumes dewaxing solvent having a temperature 25.degree.-40.degree. F below the depressed cloud point for forming a wax/oil/solvent mixture having a temperature 5.degree.-15.degree. F below the depressed cloud point, and wherein the wax/oil/solvent mixture is further cooled at 1.degree.-8.degree. F/min. to a selected separation temperature in the range of 0 to -40.degree. F for precipitating additional wax. Precipitated wax is removed at the separation temperature to produce a wax free oil/solvent mixture which is subsequently fractionated to yield a dewaxed oil suitable for use in lubricating oils.

Abstract: A process for dewaxing heavy distillate and residual petroleum oil stocks wherein a waxy oil stock, prediluted with 1-2.5 volumes dewaxing solvent, is cooled to about the depressed cloud point, wherein the cooled, prediluted waxy oil stock is treated with dewaxing solvent, in increments of 0.3-1.5 volumes each to a total dilution of 3.5 to 4 volumes solvent, under conditions of good mixing and cooling at about 1.degree.-8.degree. F/min, to a desired separation temperature for precipitating wax crystals and producing a dewaxed oil.

Abstract: A solvent dewaxing process wherein a waxy oil charge, heated for melting wax therein, is cooled to a temperature about 5.degree.-15.degree. F below the cloud point, wherein the cooled waxy oil charge is mixed under conditions of good mixing with solvent having a temperature 20.degree.-40.degree. F above a selected separation temperature in a solvent to oil ratio of about 1:1 to 5:1 for precipitating wax from the resulting mixture, and wherein the wax/oil/solvent mixture is further cooled in a second cooling zone at a rate of ca. 1.degree.-8.degree. F./min to said selected separation temperature for precipitating additional wax. Precipitated wax is separated from the mixture at the separation temperature, producing a wax free solvent-oil solution. Dewaxed oil is recovered by fractionation from the wax free solvent-oil solution.

Abstract: A process for dewaxing a waxy petroleum distillate charge stock, wherein a mixture of waxy oil and solvent, heated for dissolving all solid wax therein, is cooled to a first temperature about 40.degree.-50.degree. F (22.degree. to 28.degree. C) above a selected separation temperature, and is held at such first temperature for a period of 1-2 minutes for equilibrating wax crystallization, wherein said oil-solvent mixture, at said first temperature, is cooled to a second temperature about 15.degree.14 20.degree. F (8.degree.-11.degree. C) above said separation temperature and is held at said second temperature for 1-2 minutes for equilibration of wax crystallization, wherein said oil-solvent mixture, at said second temperature, is cooled to said separation temperature, and wherein solid wax is separated from oil-solvent mixture at said separation temperature.

Abstract: A solvent dewaxing process wherein an intermediate range waxy distillate oil, heated for dissolving all wax therein, is mixed with about 1-4 volumes dewaxing solvent having a temperature in the range of 60.degree.-80.degree. F for forming an oil-solvent mixture having a temperature below depressed cloud point. The oil-solvent mixture is subsequently cooled at 1.degree.-8.degree. F/min to a selected separation temperature for precipitating wax and forming a first wax/oil/solvent mixture. Additional solvent, at about the separation temperature, is mixed with first wax/oil/solvent mixture in an amount equivalent to about 1-2 volumes of waxy oil charge for precipitating additional wax and forming a second wax/oil/sovent mixture. Precipitated wax is separated, at said separation temperature from said second wax/oil/solvent mixture.

Abstract: A process wherein a light waxy petroleum distillate stock, having a viscosity less than about 200 SUS at 100.degree. F, is heated for melting any wax therein, wherein said heated waxy stock is incrementally mixed with a flowing stream of dewaxing solvent, having a temperature in the range of 40.degree.-80.degree. F, for forming an oil/solvent mixture at a temperature 5.degree.-10.degree. F below the depressed cloud point, and wherein the oil/solvent mixture is cooled at a uniform rate in the range of 1.degree.-8.degree. F/min. to a separation temperature in the range of +25.degree. to -40.degree. F for precipitating wax from said mixture.

Abstract: On-line sensors sense the kinematic viscosity, the infrared absorption, at a predetermined wavelength, and the sulfur content of crude oil and corresponding signals are provided to a computer circuit. The computer circuit solves the equation M%BP={C.sub.1 --C.sub.2 [1n(IRxC.sub.3)]--C.sub.4 S+C.sub.5 [1n(IRxC.sub.3)]S }1nKV, where M%BP is a particular percent boiling point property of crude oil, IR is the infrared absorption of the crude oil, S is the sulfur content of the crude oil, KV is the kinematic viscosity of the crude oil, and C.sub.1 through C.sub.5 are constants.

Abstract: On-line sensors sense the kinematic viscosity, the infrared absorption, at a predetermined wavelength, the ultraviolet absorption of a predetermined wavelength, and the sulfur content of crude oil and corresponding signals are provided to a computer circuit. The computer circuit solves the equation:M%BP={--C.sub.1 +C.sub.2 [ln(IRxC.sub.3)]+C.sub.4 [lnUV]--C.sub.5 S--C.sub.6 [ln(IRxC.sub.3)](lnUV)+C.sub.7 [ln(IRxC.sub.3)]S}lnKVwhere M%BP is a particular percent boiling point property of crude oil, IR is the infrared absorption of the crude oil, S is the sulfur content of the crude oil, KV is the kinematic viscosity of the crude oil, UV is the ultraviolet absorption of the crude oil and C.sub.1 through C.sub.7 are constants.

Abstract: The 50% boiling point, the gravity and the viscosity of waxy oil are sensed by sensors which provide corresponding signals. A computing circuit connected to the sensors provides a signal corresponding to the wax content of the waxy oil in accordance with the signals from the sensors and equations hereinafter disclosed.

Abstract: A method of dewaxing oil which employs the application of reversing electromotive force to the oil while it is being chilled, in order to prevent adherence of the wax crystals.An apparatus combination for dewaxing oil. It includes an elongated container for chilling a body of waxy oil as it flows through. The container acts as one of a pair of electrodes for applying a reversable electromotive force to the oil in order to prevent any adherence. The wax may be recovered by separation following the application of the electrical force.

Abstract: The reboiler temperature of a depropanizer tower is controlled as the function of the propane content of the feed to the depropanizer tower and of the gasoline provided by the tower in accordance with a control signal. The Reid Vapor Pressure of crude oil feeding a flash tower is determined from the propane content of the depropanizer feed while the Reid Vapor Pressure of the gasoline is determined from the gasoline propane content. A control unit includes a network which determines a change in the Reid Vapor Pressure as the quality of the feed crude oil to the flash tower changes. When the change in the Reid Vapor Pressure exceeds a predetermined limit, the network provides a feed forward signal corresponding to a desired temperature associated with the new Reid Vapor pressure. The feed forward desired temperature signal is determined in accordance with the equations hereinafter disclosed.

Abstract: A control system controls the flow rates of waxy oil and solvent entering a dewaxing unit so as to control the viscosity of a chilled slurry mix or waxy oil and solvent provided to a filter in the dewaxing unit. The dewaxing unit includes valves controlling the flow rates of the solvent and waxy oil being provided to the chiller. The filter provides a dewaxed oil and solvent mixture and wax. Using the equation hereinafter mentioned, the control apparatus utilizes the sensed refractive index of the solvent, the sensed viscosity of the waxy oil, the sensed flow rates of the solvent and the waxy oil, and the sensed filtering temperature of the chilled slurry mix to generate a signal corresponding to the viscosity of the slurry mix provided to the filter at the filtering temperature. The viscosity of the chilled slurry mix is controlled within predetermined limits by a generating signal corresponding to the dilution ratio of the solvent to the waxy oil.

Abstract: A system measures and records the API gravity the viscosity and the sulfur content of waxy lubricating oil and provides corresponding signals. A computing circuit develops a signal corresponding to the wax content in accordance with the sensed parameter signals and an equation hereinafter disclosed. The wax content signal is recorded.