US2040366A - Treatment of hydrocarbon oils - Google Patents

Description

Patented May 12, 1936 UNITED STATES PATENT OFFICE TREATMENT OF HYDROGARBON 011s Gustav- Eglofi and Jacque C. Morrell, Chicago, 111., assignors to Universal Oil Products Company, Chicago, 111., a corporation of Delaware No Drawing. Application January 12, 1934, Serial No. 706,409

, V V 2' Claims. (01. 196-36) This application is acontinuation in part of our application Serial No. 518,879, filed February 27, 1931.

This invention relates more particularly to the s 'refining. of relatively low boiling hydrocarbon distillates at elevated temperatures, especially those distillates resulting from theconversion of relatively high boiling hydrocarbons at elevated I) temperatures and pressures. 10 Ina more specific aspect the invention has reference to a process for refining cracked hydrocarbon oils of approximate gasoline boiling range under vapor phase conditions of treatment, using certain combinations of gaseous treating reagents 15*and'solid contact materials which will effect the desired. degree of refinement.

The usual method of refining cracked'distib lates is to subject them to treatment with sulphuric acid and alkaline solutions, including plumbite solutions consisting of litharge dissolved in alkaline solutions in various combinations of treatment, and subsequently to subject the acid treated product to redistillation, usually in the presenceof steam.

The present invention permits the direct treatment of the hydrocarbon vapors from the cracking process, reducing the cost of reagents and eliminating the redistillation or rerunning operation, although it is within the scope of the invention to revaporize the product in a subsequent operation and subject thevapors to treatment as'described.

Inone embodiment the invention comprises- ,subjecting hydrocarbon oil vapors, particularly cracked hydrocarbon oil vapors of approximate gasoline boiling range to treatment with sulfur trioxide and steam in the presence of selected solid metal salts which are of a substantially nonoxidizing character.

The salts which are preferred as contact materials to accelerate and modify the character of the treating reactions are certainsulfates, phose phates and chlorides, principally those of the 'so-' 45, called heavy metals. When employing sulfates an equilibrium is established between the composition of the salt and the vaporsv of sulfur trioxide-and steam so that substantially nochemical change occurs in the composition of the solid 50 contact material, although there is some reductiorrof: the sulfur trioxide on account of its oxidizing action upon the undesirable hydrocarbons and derivatives in the vapors undergoing treatment.

55 theiicase of phosphates, many of. these are;

gradually decomposed by the action of the sulfur trioxide so that in the course of extended treatments the original phosphates are converted to a large extent into corresponding sulfates of varying degrees of basicity. The rate and extent of such reactions of substitution will be determined by the mutual influence of a large number of operating factors such as temperature, pressure, relative concentration of reacting constituents, et cetera.

In the case of chlorides, the reaction of the sulfur trioxide thereon is usually more rapid so that the reactions of treatment are altered considerably due to the presence of the vapors of hydrochloric acid.

The following sulfates are" adaptable to use in treatments conducted according to the invention:

Aluminum sulfate Zinc sulfate, Y Stannic sulfate Cupric sulfate Plumbic sulfate Mercury sulfate (basic) Nickel sulfate Manganic and manganous sulfates Cadmium sulfate Under the preferred conditions of'temperature which will bejgiven hereinafter, it hasbeen found to be preferable to. use. only sulfates which are solid; under the conditions of treatment. This usually eliminates the'use of sulfates of cobalt and of' chromium on account of their tendency to flux. -A sulfate of vanadium known as-vanadyl sulfate finds application in some instances.

The following phosphates may be employed: Aluminum phosphate Zinc phosphate Lead phosphates (includes a pyrophosphate) Ferric phosphate 0 Nickel phosphate. Chromium phosphate Manganese phosphates Vanadium pyrophosphate Cadmium phosphate 7 In. the phosphate group may also be mentioned phospho-molybdates and phospho-tungstates.

. The number of chlorides which may be successfully employed as contact materials is somewhat limited by practical considerations as to cost,

melting point. and volatility. Many compounds which would be utilizable inliquid phase treatmentsfare ruled out by meltingpoint and boiling point considerations. The following chloridesr5 may be used under properly regulated operating 7 conditions:

Zinc chloride Cadmium chloride Cupric chloride Manganese chloride 7 V Molybdenum chlorides (di, tri and tetra) Chromic chloride 'It is within the scope of the invention to employ as solid contact materials single chemical corn-- 7 pounds selected from the above mentioned groups or mixtures of the same which'may be foundto give good treating effects upon any given distillate which may be treated' It is to be understood that each. specific contact substance or mixture of different chemical compounds :will exert its own peculiar catalytic or chemical influence upon the course and extent of the treating reactions so that'the different contact materials are not to be considered'as exact equivalents though they may assistin producing somewhat-analogous treating effects.

.Of the compounds mentioned asbeing utilizable some may be artificially'prepared and some may be used as minerals as they are mined.

In applying the process of the invention to practice any suitable equipment may be employed which will permit the contacting of the hydrocarbon vapors and the sulphur trioxide and steam i ;with the flow with the metal salts; for example, a suitable tower treating vessel containing the contact salts. In

lieu of direct packing of the tower or treating vessel with the metal salts an inert filling material such as Raschig rings, firebrick, crushed rock, gravel, crushed ceramic material, and the like, suitably mixed or coated with a salt, maybe employed. Similarly, any device which permits the efilcient contacting of the vapors undergoing treatment'with salts may be employed.

The tower or treating vessel containing the contact material may be directly connected to a cracking unit or to a rerun or redistillation unit so that the vapors arising therefrom may be' treated in the manner described.

It has been found desirable to neutralize the distillate immediately after condensation either by passing the condensate directly through a body of alkal such as a solution of caustic soda or by washing the distillate free of sulphur oxides with water and/or alkalis, such as a solution of caustic soda, ammonia, or the like. The neutralizing agent may also be introduced into the vapor line leading to the condenser orinto the condenser itself.

The amount of sulphur trioxide employed may vary from a fraction of a pound to, several pounds, based on a barrel of hydrocarbon distillate treated.

Various temperatures of treatment may be employed, for example, from 250600 F., more or 7 less, and the pressures may be sub-atmospheric, atmospheric, or superatmospheric.- While the results may vary with the temperatures employed,

the pressures and temperatures are chosen so that the hydrocarbons are treated substantially in'the vapor phase.

In order to reduce the intensity of the reaction the sulphur trioxide may be admixed with an inert gas and a flue gas carbon dioxide and the like and may be introduced at various successive points in the treating tower.

The effects produced upon oil vapors, particu larly those produced from the cracking of heavy hydrocarbon oils by the use of gases and solid contact substances characteristic of the'invention are in general those of polymerization or condensation of relatively highly unsaturated hydrocarbons or their derivatives, particularly their sulfur derivatives. The net result is the controllable elimination of groups of compounds which are readily polymerized under oxidizing conditions to formsubstances of a gummy or resinous nature which are undesirable in motor fuel.

The treatment herein described may constitute the sole refining action on the oil, or it may constitute one'step in a series of refining steps. It maybe preceded by the usual treatments with refining agents such as sulphuric acid, caustic soda, plumbite, filtering earth or the like, and may be succeeded by any combination of the above refining agents, followed, if desired, by distillation.

As specific examples of the operation of the process of the invention and of the results ob tained by its use, the following may be given:

(1) A California cracked distillate of approximately motor fuel boiling range may be vaporized and subjected to treatment with a mixture of sulfur trioxide and steam during the passage of the vapors in the downward direction through a stationary contact mass consisting of a mixture of a finely divided zinc sulfate. supported.

on fullers earth, the weight of the earth being sulfur trioxide may be usedin an amount equivalent toapproximately three pounds per barrel of oil. The untreated product may show a gum content of approximately 500 mgs. per 100cc. and have a reddish brown color, with a sulfur content of approximately 0.45%. product after suitable separation from spent reagents, neutralizing with alkalis and washing with water, may show a gum content of approximately 30 mgs. and a color of+25 on the Saybolt scale. The sulfur content may be found to be as low as 0.2%.

.(2) In the case of a mixed Mid-Continent The treated and West Texas cracked distillate treated with cases the untreated distillates may contain 650 mgs. of gum and have a dark reddish color while the treated distillatesmay have a gum content of only 40 mgs. and a color of 25 to, 30 on the Saybolt scale. The sulfur content may be reduced from 0.5% to 0.15%.

'The foregoing description andexamples have disclosed a process applicable to the treatment of hydrocarbon oil vapors which has a wide applicability and is capable of great variation in the methods of operation and the amounts of reagents employed. Therefore, the specific cases cited are not to be construed in a limiting sense upon the broad scope of the invention as many other modifications can be used and examples of results therefrom given.

We claim as our invention:

1. A process for refining hydrocarbon oil which comprises subjecting said hydrocarbon oil in vapor form to the action of sulphur trioxide and steam in the presence of zinc sulfate.

2. A process for refining hydrocarbon oil which comprises subjecting said hydrocarbon oil in vapor form to the action of sulphur trioxide and steam in the presence of finely divided zinc sulfate and fullers earth.

GUSTAV EGLOFF'. JACQUE C. MORRELL.