US1988083A - Process for refining hydrocarbon oil - Google Patents

Description

Jan. 15, 1935. J. c. MORRELL PROCESS FOR REFINING HYDROCARBON OIL Filed May 31, 1930 [Ni [N702 c/cw as Cl/Yorre]! arm/av Y Patented Jan. 15, 1935 PATENT. OFFICE PROCESS FOR- REF-INING HYDROCARBON OIL Jacque C. Morrell, Chicago, 111., assignor to Univer's'al Oil Products Company, Chicago, corporation of'South' Dakota Il1., a

Application May 31, 1930', Serial No. 458,717

2 Claims.

This invention relates to-the treatment of hydrocarbon oils andpetroleum distillates for the production of marketable motor'iuels. It

may-' be advantageously-applied to the treatment of cracked hydrocarbonoils resulting from the conversion of higher boilinghydrocarbons at elevatedtemperatures and usually :imder' pressureinto lower boiling hydrocarbonssuitable for motor fuels.

S'o-called straight rundistillates may and cracked hydrocarbon oils do containvarious groups of hydrocarbons including aromatic,

naphthene parafiin and unsaturated hydrocar-- bons. The unsaturated hydrocarbonsmay consist'not only-of the mono-ol fines, but also of the more highly unsaturated olefinic compounds suchas-thedi-olefines. The highly unsaturated compounds tend to polymerize, forming heavy tar-likematerial which action-as well as others forming similar compounds is promoted by the effect of light and heat. Stored gasolines also show this tendency; I

Increase in gum ina stored motor fuel causes difficulties in the operation ofthe motorby gummingup of the iced lines and the intake andexhaust valves.

In addition to-the formation of? gummy material some cracked gasolines exhibit a tendency to deteriorate with respect to anti-knock qualities, thus reducingtheir value as a-motor fuel.

It is among the purposes of my invention to avoid these difficulties and at the same time to produce marketable gasolines with respect to color; odorandstability; Intheoperation of the process of my invention, I make use of heavy metalsalts such as the chlorides; nitrates; sulphates, acetates ofiron; aluminum, antimony, bismuth, cadmium, chromium, zinc, tin, copper, titanium and in general themetallic salts of various acids, some of which will be illustrated by the examples shown. These salts are dissolved in a solvent which-may be water Qrorganic solventsaloneor in combination. As examples oi the organic solvents" I-ma-y mention alcohols,- such as methyl, ethyl,

propyl; iso-propyl; butyl, iso-butyl, amyl, isoamyl and" the like. I may also make use-oi the polyhydric alcoholssuch as glycols; glycerine and the like. Other liquid organic derivatives I which dissolve any of the heavy metal salts maybe used. It is to be understood that the solvents or mixtures of solvents are chosen with'respect tothe heavy metal. salt or salts tobe dissolved as-:well as-for the particular refining purpose in hand.

of thesalt. For example, in the case'of the sulphates, sulphuric acid may be used; in case of the acetates, acetic acid may be used and in the caseof the; chlorides, hydrochloric acid may be used. The acid mayalsobe added in suiiic'ient quantity to prevent the formation of metal sulfi'desby interaction of hydrogen sulfide thus preventing exhaustion of the treating solution from this source.

The solutions of the heavy metal salts serve as refining agents, presumably by polymeriza- 15 tion and in general conversion of the undesirable separation of the undesirable color and gum forming compounds may occur immediately upon treatment or may be later effected.

The treatment may be applied in one: or several ways. For example, I may distill the oil over the solution of the heavy metal salt or the vapors of the oil-undergoingtreatment may. be passed counter-current to thesolution, or'the vapors oi the'hydrocarbon oil undergoing treat- 25 mentmaybe contacted with a solution of the heavy 'metal'saltin a suitable-vessel or container.

In all cases the vapors so-treated are condensed and recovered. Make up solvent may be added fromtime-to time as some of the original solvent is lost by evaporation. The heavy metal salts may be recovered or reconverted when changed bychemical reaction using suitable and well known methods. The treatment may be the sole treating step or may be used in combination with other treatments-for example in the case of the vaporsthey may be subsequently scrubbed and otherwise treated by passage through a vessel containing an adsorbent material such as fullers earth, bone black and the like or with mixtures of these materials with alkalies suchas lime, caustic soda etc. Metallic oxides may also-be used either alone or in combination With-the absorbent earths and/or alkalies.

In the specific embodiment of my invention, and as' a principal feature thereof, the vapors leaving the treating zone wherein they are subjected to the action-of a solution of heavy metal salts, are subsequently passed through a column wheretheymay be scrubbed by reflux condensate, andotherwise subjected to a scrubbing or fractionating action, the principal purpose of which is to remove coloring material, or color formihg subs'tances present in the said vapors, particularly those which-have been formed as aresult of polymerization, condensation or association, owing to the treatment with the heavy metal salt. I have found that such polymerized coloring matter, or color forming material, which would ordinarily condense with the vapors and remain as a solution or dispersion therein, may be removed by subsequent fractionation after leaving the treating zone, even though the treatment has been effective so far as the action of the metallic salt solution itself is concerned, and that this is an important step in the process of treating hydrocarbon vapors. I prefer to fractionate the vapors before entering the treater, as well as after although the two steps may serve difi'erent purposes; the first being directed primarily to the removal of a substantial proportion of high boiling material, whereas the second is directed primarily to the removal of coloring matter, which it is believed undergoes further changes in the second step namely fractionating and scrubbing-permitting the removal of these undesirable components thereby.

In the case where the vapors are contacted with the solution of the heavy metal salt either by passing the solution counter-current thereto or by passing the hydrocarbon vapors through a solution of the heavy metal salt or otherwise contacting the hydrocarbon vapors with a solution of heavy metal salt, I prefer to fractionate the vapors to the desired end point before such treatment and preferably the vapors are subsequently subjected to a fractionating or scrubbing action either by passing through a dephlegrnator or fractionating column or element containing bafile plates for the purpose of removing suspended or entrained tar-like or polymerized products. Alkaline material may be injected into the fractionating column or scrubber and/or condenser to prevent corrosion. I may also treat the hydrocarbon oils by contacting with the solutions of the heavy metal salts and removing the sludge or other reaction products therefrom. Where the solutions are contacted directly with the oil to be treated it is preferable to be used in combination with other refining steps in suitable order such as by alkali washing acid treatment, treatment with earthy material, metallic oxides, dry alkalies, etc.

The process may be used in direct connection with a cracking unit or in connection with an ordinary distillation unit so that the vapors either from the primary cracking process or from the redistillation of the primary light product of the cracking process may be treated in the manner described. When connected directly to a cracking unit, I prefer to scrub the gases with a reagent or material to remove hydrogen sulphide such as lime, caustic soda and in general alkalies, oxides of metals, etc. The process may also be adapted to the treatment in the usual manner as described, i. e. by contacting the heavy oil with the solution of the heavy metal salt removing the sludge and preferably treating with an alkali and subsequently water washing the distillate.

The distillate to be treated, supplied through line 1 and valve 2, is pumped through pump 1', line 2' and may be passed through valve 5 directly to heating coil 3 located in furnace setting 4. The distillate leaves the heating coil controlled by control valve 6 in line 6 and enters evaporator 7. Steam may be introduced through line 8, controlled by valve 9, to assist the vaporization. Unvaporized residue may be withdrawn through line 10 controlled by valve 11. The

vapors leaving the evaporator 7 pass through line 12 controlled by valve 13 into fractionating tower 14. Steam may be introduced through the line 15 controlled by valve 16, to reboil the reflux formed in the tower 14. The unvaporized residue may be passed through line 1'7 controlled by valve 18 to storage or it may be returned after reboiling into the heating coil 3 through line 19, valve 19, pump 20, lines 21, 21, valve 22' and line 2, or the reflux may be passed through line 21 controlled by valve 22 through a separate heating coil 23, passing into evaporator 7, through line 24 controlled by valve 24.

The raw charge may also enter the fractionating column 14 through line 25 controlled by valve 26, the reflux being treated as heretofore described.

The vapors leaving fractionating column 14 throughline 27' and valve 28 enter the treater 27, preferably through a perforated rose or similar arrangement 28. Various gases may be introduced into vapor line 28 through line 33 and valve 34 and thence into the treater 27 e. g. hydrogen, oxygen or gases containing these. Reducing and oxidizing gases are of course introduced separately. Finely divided metals may also be added, especially if the solution is made acid by further addition of acid. The treating solution, consisting of the heavy metal salt and a solvent, is placed in treater 27 using a sufiicient amount to permit thorough treatment of the vapors which bubble up therethrough and contact with the treating liquid. In order to make up for the loss of solvent due to evaporation, additional solvent supplied through line 29 and valve 30' is 'fed by means of pump 29 through line 30, controlled by valve 31. Line 32 controlled by valve 32' permits the withdrawal of the solvent or other liquids accumulating in treater 27. Drawoff lines 33 controlled by valves 34 permit removal of liquid and adjustment of levels. The treated hydrocarbon vapors leaving treater 27 pass through line 35 controlled by valve 36 into the secondary fractionating column, or scrubber 37. Ammonia may be introduced through line 38 controlled by valve 38 to neutralize acid vapors passing from the treater. Likewise an alkaline solution such as sodium carbonate or sodium hydroxide, may be fed through line 39 controlled by valve 39'. Steam may be introduced through line 40 controlled by valve 40' to assist in vaporization.

The bottoms accumulating in tower 37 may be withdrawn through line 41 controlled by valve 41'. The vapors leaving tower or scrubber 37 pass through line 42 controlled by valve 42' into cooler and condenser 43. The condensed liquid is collected in receiver 44. Control valve 45 permits additional control of the pressure. The liquid is removed from receiver 44 through line 46 controlled by valve 46. Gases and vapors accumulating in receiver 44 are removed through line 47 controlled by valve 47'. A portion of the liquid in receiver 44 may be withdrawn through line 48 and valve 49 and returned by means of pump 48 to tower 37 through line 49', and valve 50 or to tower 14 through line 49', valve 51 and line 52. Any other suitable cooling fluid for refluxing may also be introduced through line 52 and valve 52' into tower 14.

It is to be understood that this is only one of the many forms of apparatus in which the process of my invention may be carried out for example, a shell still may be substituted for the pipe coil heated as shown and in either case a vessel containing dry neutralizing agents such as lime or caustic soda, alone or in combination with earthy adsorbents, metallic oxides etc., may be used following the treater 27. The treater may also be directly connected to a cracking unit, in which case I preferably make use of neutralizing agents or other means to remove hydrogen sulfide before passing the vapors to the treater.

As examples of the process, I may take cracked hydrocarbon vapors direct from a cracking unit and contact with a 50-75 percent solution of ferric chloride in a solvent containing 75 percent water and a small amount of hydrochloric acid. The product from this treatment is Water white, sweet in odor and otherwise marketable as a motor fuel. Previous to treatment with solution of heavy metal salt, the hydrocarbon vapors were fractionated to the desired end point and after passing through the solution were subsequently passed through a fractionating column to remove entrained tarry material. The treating solution was placed in a vessel and some of the solvent was fed in from time to time. The vessel was made of corrosion-resisting material as some hydrochloric acid was formed due to the hydrolysis of the ferric chloride and in order to avoid corrosion of the condenser a small amount of ammonia was injected therein.

A mixture of '75 percent water and percent ethylene glycol containing '75 percent of ferric chloride by weight was substituted in the above example with similar results in regard to the product. Similarly solutions of zinc chloride,

tin chloride, zinc sulphate and others in water alone and containing small amounts of acid gave good results. A mixture of water and isopropyl alcohol were also used as a solvent for the salts producing good results. In some cases some of the salt remained suspended but the results were good.

It is to be understood that owing to the broad scope of my invention there are many possible solutions or combinations of solutions of heavy metal salts and solvents as well as combinations in treating steps and methods of application of the process and in View of this the examples and illustrations given are not to be construed as limitations thereon.

I claim as my invention:

1. A process for refining hydrocarbon oils which comprises treating the same in vapor form with an aqueous solution of a heavy metal chloride containing hydrochloric acid in amount sufficient to prevent hydrolysis of the chloride, thereafter fractionating the vapors in the presence of alkaline material to remove polymerization products formed by the treatment and to neutralize said vapors carried over from the solution, and then condensing the fractionated and neutralized vapors.

2. In the refining of hydrocarbon oils, the step which comprises treating the oil in vapor form with an aqueous solution of a heavy metal chloride containing hydrochloric acid in amount suflicient to prevent hydrolysis of the chloride.

JACQUE C. MORRELL.

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