US2578685A - Method of dewaxing petroleum products with monobromo-monochloromethane - Google Patents

Description

Patented Dec. 18, 1951 METHOD OF DEWAXING PETROLEUM PROD- UCTS WITH MONOBROMO-MONOCHLORO- METHAN E Karl A. Fischer, College Park, Md.

No Drawing. Application November 10, 1949, Serial N0. 1 26,675

3 Claims. (01. 196-19) (Granted under the act of March 3, 1883, as

The invention described herein, if patented, may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

This invention relates to an improvement in dewaxing petroleum products and more particu larly to dewaxing lubricating oil distillates and raflinates with the agent monochloro-monopromo-methane.

The present day method of removing waxes from petroleum distillates and raiflnates comprise amended April 30, 1928; 370 0. G. 757) luting agent which is non-flammable and will the dilution of an oil with suitable solvents or solvent combinations such as gasoline, esters, l etones, hydrocarbons such as benzene and toluene,

brominated hydrocarbons, chlorinated hydrocarbons, fluorinated hydrocarbons, and many others. The principle of the method utilizing these agents is to compose a diluting liquid which has the property of being homogeneously miscible with oil at low temperature while its solving leave much to be desired in simplifying and economizing dewaxing of petroleum products. Particularly, the adjustment of solvent couples to the proper selectivity and the fire hazard which is involved in the use of propane or benzene combinations is a considerable drawback. Further, the use of known chlorinated hydrocarbons frequently requires more chilling than is feasible or practical in many types of systems because of their oftentimes undesirable solvent power for paraflin waxes. In attempting to offset this solvent power by balancing chlorination to meet the requirements from the wax side, the danger of phase separation occurring in the oil phase becomes a detrimental problem relative to obtaining oils of desired pour points.

It is therefore an object of this invention to provide an improved oil dewaxing agent which simplifies the process of dewaxing petroleum products without danger of oil-phase separation.

It is another object of this invention to provide an improvement in economizing the process of dewaxing oils.

A further object of this invention is to provide an improved solvent process for dewaxing lubricating oils, distillates and raflinates with a diserve to extinguish hydrocarbon fires.

Another object of this invention is to provide an improved dewaxing agent and process utilizing a monochloro-monobromo-methane solvent diluting agent in which the wax and oil are readily soluble at normal temperatures and provides no pronounced selectivity to petroleum hydrocarbons at low dewaxing temperatures whereat the wax separates from the mixture.

Other objects and advantages will be apparent from the following examples.

Illustratively, for example, a petroleum railinate diluted with 200% per volume of monochloro-monobromo-methane at normal room temperature and chilled to 20 C. releases the wax as physical bodies which partly float on the surface of liquid mix due to the differences in specific gravities. The wax, in some cases, can be spray-washed by the diluting agent and removed as in a flotation process which eliminates the usual filters or centrifuges. However, in most cases where the wax content is high, better results in pour point values are obtained by use of a conventional filter or centrifuge process.

More specifically, to illustrate the results obtained by use of monochloro-monobromo-methane as a diluting solvent for dewaxing hydrocarbon oils, it was discovered that a refined heavy lubricating oil from Pennsylvania stock having a pour point of 20 C. when mixed with 1% paraifin, on a basis of weight measurement, and diluted with 200% monobromo-monochloro-methane per unit volume, at room temperature, chilled to 20 C. produced, when filtered, and twice washed with 25% additional monochloro-monobromo-methane, a lubricating oil with a new pour point of -21 C. upon evaporation of the diluting solvent. The separation of the solvent from the oil, after dewaxing, is by any conventional means as heating to boil off the solvent.

In neither of the above processes was there any sign of oil phase separation at the dewaxing temperature of 20 C. and the wax appeared to separate quantitatively.

In addition, this solvent may be used in combination with other selective and non-selective solvents, of the characteristics heretofore indicated, with or without inflammable characteristics, and, in addition to economizing on their use, provides a fire extinguishing action against the inflammable hydrocarbons.

As heretofore mentioned some solvents as ketones, alcohols, esters, dichloromethane and certain other chlorinated hydrocarbons when used 3 alone or in combination with other solvents cause a phase breakdown of the oil components at dewaxing temperatures. However, the pronounced selectivity of such dilutents at low deto 100 oil parts provides at -20 C., with convene-v tional centrifuging or filtering and conventional removal of solvents, a dewaxed oil of improved pour point value. The process of dewaxing' the oil is simplified by the disregarded of oil phase 7 breakdown and the ease of wax separation facilitated at the dewaxing temperature of 20 C. or lower, if desired.

Having thus described the general mode of utilizing monochloro-monobromo-methane in dewaxing petroleum products it will'beapparent that the improvements provided thereby maybe applicable to processes fallingwithin the scope of 'my claims.

What 1 claim is:

1. A process of dewaxing oils, which comprises diluting an oil with monochloro-r'nonobromo- 4 methane, chilling the mixture, and separating the wax.

2. A process of dewaxing petroleum products, which comprises subjecting the petroleum to the action of monochloro-monobromo-methane in combination with a more selective solvent, chilling and separating the wax.

3. A process of dewaxing oil distillates and rafiinates, which comprises diluting the oil distillates and rafnnates with monochloro-monobromo-methane in amounts constituting substantially double to three times the volume of the oil content, chilling the diluted mixture until a substantially quantitative separation of the wax from oil constituents occurs, and separating the wax.

KARL A. FISCHER.

REFERENCES CITED The, following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,988,706 Swift Jan. 22, 1935 2,049,059 Goss et a1. July 28, 1936 2,129,752 Whiteley Sept. 13, 1938 2,137,218 Govers Nov. 15, 1938 2,162,682 Terres et a1 June 13, 1939

Claims (1)

1. A PROCESS OF DEWAXING OILS, WHICH COMPRISES DILUTING AN OIL WITH MONOCHLORO-MONOBROMOMETHANE, CHILLING THE MIXTURE, AND SEPARATING THE WAX.