US2052812A - Process of refining oil - Google Patents

Description

sept. 1, 1936. g, E Wm 2,052,812

PROCESS OF REFINING OIL Filed May 18, 1933 /Nl/ENfOR atented Sept.. l, 1936 2 Claims.

This invention relates to improvements in the refining of oil and apparatus therefor. It refers particularly to means for applying alkali metal to promote molecular rearrangement and to promote the association of xed gases with vapors while maintaining the metal in unusually active form.

Prior methods of applying alkali metal have involved temperatures inadequate for high activity and application in a manner to retard or prevent action which might otherwise occur or they have involved conditions which prevent economical recovery and activation. In other instances intolerable or unusual and unnecessary hazards of operation have been involved. The oil to be treated has not been utilized in the process while freshly formed and active. After treatment with metal, the oil has not been treated or recovered to yield high quality.

I have found that alkali metals become very active at above about 300 C. and they may beneiicially treat oil in the vapor phase at temperatures up to about 500 C. Oil to be treated is preferably raised to the cracking temperature and quickly processed by contact with the metal. To insure high activity and to facilitate recovery, I maintain the metal in stream form and utilize the stream to carry away formed resinous or carbonlike substance, which are derived from impurities contained in the oil or which may be otherwise precipitated as by cracking.

' The amount of carbon formed during cracking and often the amount of formed xed gas may be considerably reduced or the yield of gasolinev range oil may be increased or both may be realized. To accomplish this I add fixed gases to the vapors of freshly formed oil which may have been cracked appreciably but preferably not of the order of usual cracking. 'Ihe fixed gases so added are preferably freshly formed from a cracking process currently operated with my process or they may be gases formed in producing vapors-to be treated` by my process, or both.

Ihe metal may be admixed with a compound of alkaline metal such as alkali hydroxides, aluminum chloride or other halides or sulfates or other salts. The mass is so compounded as to have unusual fluidity and activity and so that a selected metal may be freed almost to the exclusion of others as is disclosed in U. S. Patent 1,913,145 and in my French Patent No. 755,875.

. Operation may be carried out with a multiplicity of zones of diiferent composition and temperature and otherwise as disclosed in Ser. No. 482,267 iiled Sept. 16, 1930, this application also shows recognized that prior efforts treatmentof vapors of oil with alkali metal produced in situ and diluted in a molten mass to yield desired activity and further showing that such metal may be used to promote or iniiuence chemical reaction of oil so as to purify the same and to crack the same if desired; it further shows that the action may be continued from one zone to another with different temperatures in each ranging from 200 C. to 350 C. or at 400 C. whereat the metal is especially active; and that vapors of cracking may be treated at 400 C. or above. Other general features of a preferred method are described in my French Patent No. '156,203 while details and special features are disclosed in Ser. Nos. 613,080 led May 23, 1932; 613,151 led May 24, 1932; and 641,558 led Nov. 7, 1932 and my application Ser. No. 671,187 filed on May 15th, 1933. This application is a continuation in part of the process and apparatus inventions described in those patents and disclosed in those applications.

By maintaining high activity of both the metal and the hydrocarbons, unusual rearrangement of the molecular structure may be obtained. It is have been made to utilize sodium for treating gasoline and the like and that suggestion has been made that sodium might be used for treating oils however the manner and mode of proposed applications have been such as to render them inoperable or devoid of prospects of commercial or practical success. The color may be removed to any desired degree. Stability is increased. Mild oxidation may be applied just before contact to further improve stability. Viscosity index is increased. Dielectric strength is increased and ability to form acid lowered. In many instances is lowered.. Application of high pressure of from about a hundred to several hundred pounds has been found to associate or combine gases and light vapors. Heavy oils may be treated under high vacuum. In this manner heavy portions of the oil withstand rearrangement into light hydrocarbons and the heavier portions are thus stabilized and suitable for use as a lubricant, the stability being increased when mild oxidation is applied as a preliminary step. By quickly fractionating and condensing the vapors I am able to prevent deterioration after treatment. I utilize the special quick heating of a pipe still but preferably to a considerably less degree of cracking and in some cases permit cracking to continue somewhat while metal is applied. The oil residual to vapors leaving the soaking tank may be kept more iluid to facilitate later treatment the specific gravity as with alkali metal. One stage of contact is preferred to be with alkali hydroxide maintained anhydrous while another stage is preferably with a high concentration of metal. My process may 1 involve metals which possess or which yield onethese vmetals be made iiuid atthe temperature f of application. These metals are of one unpaired electron in their entirety or have an active percentage of unpaired electron lat the condition of application. The common commercial metals are the alkali metals, aluminum, calcium and barium. The three latter are required to be contained in admixture with other metals and/or compounds and are preferably applied under high vacuum. The metals are selected as the result of experimentation with the particular oil to be treated. As an example, when potassium is applied to a certain oxidized oil, the reaction is so intense that the point or range of increased stability may readily be exceeded and instability. as regards oxidation values will result. If sodium is applied vto the same oxidized oil readily controlled to give high stability of the oil. The intensity of reaction may likewise be controlled by the concentration of the metal or metf als used and by the activity of the coacting fused compound. One stage may contain fused mass containing aluminum chloride.

Impurities are alteredand removed from the contact zone with circulated molten mass containing metal. Some of the altered products may be concentrated or removed from the circulated mass by means of mineral oil. The mass may be activated by electrolysis of part thereof and the stream thus maintained in active form. The electrolysis may be to decompose products and/or water or other formed compound such as an organic sodium salt or alkalihydroxide or chloride and by the general means shown in Patent No. 1,913,145 and my applications Ser. Nos. 641,.- 558, 659,900, and 665,560. It is to be noted that the oil is generally treated in two portions, one

beingvaporous and the other liquid. The liquid portion may be treated as disclosed in Ser. No. 670,742 filed May 6, 1933. Thus a filter aid or adsorptive clay-like substance may be used for either filtration or evaporation or both and the evaporation from a thin lm may be carried out simultaneously with treatment by having active adsorptive surface or metal or both present. In thus distilling the oil I prefer that' the temperature be between about 200 C. and 350 C. while the relatively light vapors are treated with a stream of active molten mass at between about 300 C. and 500 C. The lower range of distillation although somewhat below the temperatures of cracking as ordinarily accepted or recognized, yields appreciable rearrangement and formationof ylights under the iniiuence of the metal which also gathers appreciable impurities and prevents them` from undesirably influencing the reaction of the" second zone or other subsequent zones of treatment. For some purposes the temperature of the distillation may be held at above -whereat appreciable rearrangement into lights it may be occurs. The treating steps cooperatively act and are adjusted as to Vfactors such as temperature land time of contact so as to yield the desired amount of rearrangement in view of the oil treated and test or trial runs. l,

I have found that freshly formed fixed gases or ixed gases heated to about 400 C. or 500 C. 1

vquickly introduced into a iractionating zone or quickly condensed into fractions or quickly fractionated after condensing. In this manner the detrimental eiect of heat without the zone of iniiuence of metal is reduced to a minimum and it is possible to obtain improved results. My invention may therefore provide for quick fractionation after a short period of treatment of less than about a minute or so, which treatment is with freshly formed metal maintained active and recoverable by the stream now. Fixed gases alone or iixed gases with very light vapors may be similarly associated.

In some instances, I prefer that the liquefied oil, after treatment with molten mass, be flowed through a. pipe still and cracked and rearranged while in contact with dispersed alkali metal. Ordinarily the deposit in sucha still is bothersome however by l'rst treating the oil and thenlimiting, the amount of metal to about a pound per barrel or less, good operation is had. This previously treated oil may be mildly oxidized before passing through the pipe still with alkali metal. It is preferred that a separate still be used for this purpose. Similarly the effluent from line 6 may betreated in another still but I generally prefer to remove a part or all of the suspended matter as by contact filtration in diluted form. Treated or partially treated light oil may be used for such dilution.

An arrangement for carrying out the process is illustrated in the drawing. Oil may be introduced by means of line i to pump 2 to iiow oil 'desirable to add hot gaseous iiuid as by means of inlet 1. Connection 8 is provided for one of the vessels 4 as for retreating some of the liquid. This may be added to that from line l. Line 9 may be used to introduce hot reactive gases or for other purpose. By applying very hot gaseous iiuid as vapors overhead the foaming is decreased and entrained particles may be volatilized in part.

Mixing tower I0 may be used for treating vapors from separator 4. In instances very mild oxidation may be promoted by introduction of vapors of nitrated substances or air that they may be thoroughly mixed and reacted in part by oxides of metal coated on lumps supported on plate l I. Clay-like substances or metals may be used. If desired to remove heavy matter at this point tower filler with appropriate adsorptive or contact surface may be carried by support Il and some cooling effect within i0. This may be facilitated by introduction of cool liquid through line I3 also usable for introducing oxidant or fixed zones. Substance drained from I electrolizable substance to cell 25,

lso

aosaeia tower I0 may be discharged through outlet I 2. A connection I4 permits iiow of vapors to reaction tower I5 whereat they are treated and flown through outlet I6. It will be seen that this method of contact involves a short time periodof from about a. few seconds to several minutes.

Treating agent as molten mass is circulated through distributor I1 in stream flow through line I8 to storage tank I9 thence by pump tank 20 by means of line 2I. `Pump 23 driven by shaft 22 forces the mass through line 23' to distributor l?. A line 24 may be used to flow a portion of through line 26 and to pump 23. Material to be electrolyzed another stage or from another source as by means of line 2i. Mineral oil to be treated, or already treated, or recovered may be owed through line 28 as for example to concentrate or iiush out altered impurities collected from the reaction tower and discharged with extracted impurities through lines 29 and 30 also usable for other purposes such as for adding make up alkaline compound, equalizing pressure and for period in clearing of the apparatus. Vessel lI9 or a similar vessel may be agitated to facilitate treatment with oil. Outlet 3I may be used for withdrawing the contents of tank 20. Line 32 may be used to introduce oil or inert lgas for protection and as-an equalizer such as by supplying the same under pressure at line 32. The bushing of the shaft 22 is thus protected and leakage of molten mass prevented.

Fractionating column 33 receives vapors from column is, for some treatments of may be maintained at negligible values and quite complete or thorough separation is obtainable. Vapor outlet 313 leads to condenser 35 with line 3B for backow and line SI-for forward iiow. Pressure control means may be applied to 36, or to i6 or lli. that the parts are under appropriate pressures. With gasoline production and l5 are about the same pressure throughout.

The heavy portions from fraction schematically illustrated as being discharged from line 38 may be introduced into inlet I for retreatment or mixed with the contents of tank@ as by introduction at I it being preferable to preheat it before such introduction and to avoid undesired change by storage. For purposes of illustration it may be considered that oil from 38 is introduced as by means of line 'i and that the so blended heavy oil is continuously discharged from line 6 into a storage tank not shown. Later this blended oil may be run through the same or similar apparatus or by intruding it through line I the pipe still and separator being used as an evaporator while the system is held under vacuum so that treatment may be at atemperature of between about 200" C. and about 350" C. lWhen 1 the oil is to be oxidized dinitrobenzene or other similar mild oxidant may be mixed with the high vacuum is used the fractionating column is designed to give no substantial back pressure the apparatus of Ser. No. 461,941 being usable for such purpose. That oil may also be added to the residue from tank 4 for other treatment by volatlization or as by thin film evaporation under quickly fractionates them. Such vacuum so that components of the residual of tank d may be morereadily evaporated or treated or both. Similarly a. lighter portion of the ldischarge from 38 may be so used as it might be derived from other fractionation as by withdrawingv vapors from a lower section of the column. Vapors may be passed upwardly through line 38. Line 39 may be used to introduce gases or light or other vapors. At times they are useful for cooling and for re protection. Line t0 may be used for introducing reactive gaseous fluid.

The vessels are preferably heating of the lines and valves found desirable. treating agent be kept fluid at all times and that air be excluded from such molten masses while they are to be maintained anhydrous and while they contain the metals such as sodium and further that air be excluded from such metals and compounds throughout their reactive existence after electrolysis thereof. Where possible I prefer to associate the treating agent with inert gas or or cocks has been provided with outlets other than shown and operated with companion parts and usual auxiliaries. Other steps andY means equivalent to those disclosed may be used. l

The use of alkali metal appreciably reduces the gum value and otherwise renders gasoline stable especially when oxidation is applied just before nal treatment with alkali metal. When gases are associated the amount thereof becoming a part of liquid distillate is generally between about 2 o and about 20% of the weight treated. In the case of oils of lubricating range the oil is found to be unusually stable as regards decomposition by heat and oxidation and viscosity index is found to'be considerably higher than that of the same oil which has not been so treated and thus for example if the lubricating range component of the oil normally has a viscosity index of about 90, treatment in the mannerhereof may be controlled and some times beyond.

Characteristic of such oil is its high demulsibility which is generally a number of times greater than that of the same oil found which would not respond readily to the process. Oils of unusually high sulphur content have been successfully treated and rendered colorless inpractically every quality provided operating procedure such as distillation and fractionation under vacuum as might 1. The process of cracking petroleum oil in order to promote molecular rearrangement which comprises passing the oil into a relatively small coil heated to about cracking temperature to ing the vapors as formed to a mixing zone and mixing reactive gases derived from cracking petroleum oil in a separate process, and treating the resulting mixture in a reaction zone by contact with a recirculated stream of molten mass containing light active alkali metal to simultaneheated. Electric I consider it essential that the ously rearrange portions and to associate portions of the gaseous uid while simultaneously producing condensed impurities within the reaction Zone and removing the impurities with the discharged stream of the metal of the recirculating stream, discharging the so treated vapors into a Zone of fractionation and separating the treated vapors into portions of diiierent boiling points, and wherein the time of treatment from the cracking coil to the time of the fractionation is less than about fteen minutes and the recirculating mass containing alkali -metal is held at a temperature between about 300 C. and about 500 C.

2. The process of cracking petroleum Adil for rapidly promoting the molecular rearrangement which comprises passing the oil into a heated small coil whereby the oil is quickly brought to a cracking temperature so that portions of the oil are vaporized, separating the vapors from the oil, mixing said separated vapors with xed reactive gases formed in the cracking of petroleum oil in a separate process, passing the mixture of vapors 5 and gases into a mixing zone wherein the mixture is mildly oxidized in the presence of air, then pass-g ing the mixture of vapors and reactive gases into a reaction zone wherein the mixture is subjected to countercurrent treatment with a recycled l@ Astream of molten alkali metal, said alkali metal being maintained at a temperature between 300 C. and 500 C., passing the treated vapors to a fractionating Zone to separate the treated vapore into portions of diierent boiling points. 'g5

JUSTIN F. VJAIT.

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