US1582923A - Art of removing wax from oil - Google Patents

Description

Patented May 4, 1926.-

, UNITED STATES.

'HARRY r. GLA'IB Am osoan n-unansxx', F wncrrme, INDIANA, assrenons T0 STANDARD OIL COMPANY, OF WHITING, INDIANA, AND GHICAGO, 'ILLINOIS, A

CORPORATION 01B INDIANA.

Am or REMOVING wax 'rnom OIL. 1

No Drawing.

lowing is a specification.

The present invention relates to the art of removing wax from lighter wax-bearing d1s tillates from mineral oils which have been subjected to little or no cracking or thermal decomposition during distillation. An ex ample of such an oil is that known as 34 distillate from continuous or batch fireand steam distillation of crude oil. This distillate derives its name from the 'fact that the cut forming it is started when the stream from the still has agravity of approximately 32 to 34 Baum. The average gravity of 34 distillate is from29 to 31 Baum.-

Lightwax-bearing, substantially un- Icracked oils of this character have hitherto not been freed from wax bv chilling and Y to be readily filtered-through I diluted oil. willhave ayisco'sity of 75- c- 45- fif filter pressing by reason of the fact that the nature of the wax differs from that of ordinary parafiine or crystalline wax and clogs or blocks the filter cloths of the presses. It has hence been customary, in order to free this type of oil from wax, to subject itto'a further distillation, usually with steam present in such limited quantities as to permit a considerable cracking orthermal decomposition of the oil during its distillation. As a result of this redistillation, the character of.

the wax appeared to be altered enabling it filter presses when'chilled.

We have found that oil of the character described above may be freed from its Wax content withoutredistillation by diluting it with .an oil, preferably substantially waxfree, of somewhat lower viscosity so that the onds Saybolt or lower ata temperatu of 100 F. The average viscosity of; the 34 distillate is 80 to 85 seconds Saybolt at 100 F. lrVe have found that the most satisfactory and practical results are secured by dilution to a viscosity .of fto= seconds Saybolt andv preferably about 60. After such dilution the oil may be chilled and filter-pressed in the usual manner in' accord- Appli cati on filed July 7, 1922. Serial K015733753.

ance with the cold test desired in the product. Any suitable diluent oil may be employed; for example, pressed distillate, or

an unpressed distillate of somewhat lower viscosity, such as the 30 Baum gravity distillate from tower or coking stills having a viscosity of about 50 seconds Saybolt at 100 F., and the like. The presence of wax in the diluent, for example, in the case of the last ment-ioned diluent, does not interfere with the present operation.- We may also use as a diluent the'substantially waxfree portion of distillate from the fire and steam or continuous stills just preceding the 34 distillate; for example, we may include with the 34 distillate the cut preceding it beginning, forexample, at about 37 Q Baum. The diluent employedis of a,

lubricating oil type; that is, of higher Specific gravity and viscosity than burning oils.

The proportion of diluent employed may vary in accordance with the'nature. of the diluent ',and the viscosity to which it'is desired to reducethe diluted mixture. For example, when pressed distillate or tower still distillate is employed as the diluent, from '10 to 25% may be used. The precise proportion employed does not substantially affect the effectiveness of the filter-press operation, but is controlled by the expense of further refining subsequent to presaing and like operations.

The diluted oil is chilled in the usual man- 3 ner, for example, to 0 or -10 ,F. and g tion of the desired lubricants in any desired manner. is s ometimes found desirable, as in pressing other oils, to carry out the' filter-pressing'in two stages, chilling sa to 10 to 15 F. and filter-pressing in the first.

stage and subsequently chilling the once- --pressed oil to. a lower temperature, say 0 F. or -10."F. and again pressing the oil.

Weclaim:'

. no .1. The method of separating wax from lighter wax-bearing, substantially uncracked oil distillates which consists in admixing" therewith'a hydrocarbon oil-of lower viscosity and heavierthan burning oil, chilling and filter-pressing the mixture.

2. 'The method of separating wax from lighter wax-bearing, substantially uncracked oil distillates which consists in admixing therewith a hydrocarbon oil of lower vis- 5 cosity and heavier than burning oil in quantity suflicient to produce a mixture having a viscosity below 75 seconds Saybolt at 100 F., chilling and filter-pressing the mixture. 3. The method of separating wax from 1 34 distillate which consists in admixing therewith sufiicient lower viscosity hydrocarbon oil heavier than burning oil to reduce its viscosity to below 75 seconds Saybolt at' 100 F., chilling and filter-pressing the mixture.

4. The method of separating paraflin wax from the first wax-bearing cut from'the fire and steam distillation of petroleum oil which consists in incorporating in said oil s'ufficient of the cut from the distillation of petroleum 20 oil preceding the first wax bearing cut to reduce its viscosity to below 75 seconds Saybolt at 100 F., chilling and filter-pressing the mixture. 7

HARRY F. GLAIR. OSCAR E. BRAN SKY.