US1624848A - Treatment of oils - Google Patents

Description

April 12 1927.

w. o. SNELLING' TREATMENT OF OILS- Original Filed Ma ,v5, 1915 Patented Apr. 12,1927.

UNITED STATES PATENT- OFFICE.

WALTER O. SNELLING, 0F .ALLENTOWN, PENN SYLVANQIA, 'A SSI GNOR TO GASOLINE PRODUCTS COMPANY, INGI, OF NEW YORK, N. Y., A CORPORATION OF-NEW YORK.

TREATMENT or one.

Application filed May 5, 1915, Serial No. 26,110. Renewed October 17 1922. Serial No. 595,167..

This invention relates to the treatment of oils; and it comprises a process of treating petroleum oils wherein a body of petroleum material of any nature is heated to a high temperature until a condition of e uilibrium among and between the various' ydrocarbons therein is established and wherein fresh petroleum material is supplied to said body more or less continuously and at a rate insuflicient to disturb substantially the equi librium relations in said body, one or more of the products of the equilibrium being withdrawn ina similar manner; as by heat-f ing a pool or bodyof high boiling oils, such as crude oil, gas oil, etc., in a roomy chamher, the capacity of such chamber being more than twice the volume of oil (calculated on the .volume of cold oil) maintained therewithin, tillanequilibrium is established beforth and as claimed.

The production oflow bdiling'oils from- Y high boiling oils by heating such high boiling oils, with or without. pressure, is a very old thing intheart; being the operation which is ordinarily known as cracking, Sometimes the oil to be cracked is maintained in a still; sometimes it is run through a hot tube and many other variations of the high temperature idea are known. -But in all, the operation is more or less a-distilling operation; the effort isto withdraw the low boiling products from the zone of high heat as fast as theyare formed. The low boiling 4 side; that is, .by heating lightoils, or even hydrocarbon gases, .under suitable heavy products formed by these cracking opera.- tions are of low grade, being largely unsat'urated. In a cracking still operating at the ordinary pressure the temperature is usually above 600 F. while the end boilingpoint of commercial gasoline is'about 350 F. Un-

o der these conditions the gasoline can of course remain in the liquid. undergoing cracking only momentarlly and it is evaptween liquids, vapors and gases therein, and

orated and removed away substantially as fast as it forms therein. Such as is formed in the vapors is withdrawn with the vapors.

color, having an offensive odor, sooting in the gas engine, etc. I attribute the formation of unsaturated products, which is the result of all'cracking operations, to the fact that the first products of the breaking down of oil are. largely ethylenic groupsand in the ordinary operation the products are withdrawn from the zone of heat so ra idly that not suflicient time is afl'orded'for further rearrangement with saturation.

I have found that the action of, heat and pressure upon oils' does not, as isusually presumed, go only one Way; it does not merely result in the formation of breakingdown products. On' the contrary, I have.

found that under proper conditions an equilibrium appears in which breaking down and reconstruction actions go forward until a certain balance obtains between the concentration or amount of the gases, of the low boiling oils, and of the high-boiling oils in the space afforded for'act'ion. Beinga true equilibrium it can be approached from either side; that is, I'can heat a' heavy oil unde proper definite conditions until equilibrium is obtained and produce gases togetherwith what Lmay call a synthetic crude oil; an oil much resembling natural crude petroleum. and containing a definite amount of low boiling hydrocarbons like gasoline, A

definite amount of gas is also produced. On the other hand, I can produce this same equilibrium and make the same types. of synthetic crude oil by approach from the other pressure and at a high temperature. I have, for example, so converted propaneand other permanent. gases into equilibrium mixtures containing high-boiling hydrocarbons, some bricating oil with production of a certain proportion of. gases.

may termed the expansion space space not the same vessel (giving an expansion space oil, intermediate oils As stated, I regard this operation as resulting in the production of a true equilibrium; an equilibrium which exists between paraflin, high boiling oils like lubricating like gas oil, kerosene, gasolineand gases. Being a" true equilibrium if. one o the products of equilibrium is removed such a product tends to reform at the expense of the other bodies which, together, are in equilibrium. That .is, if I treat crude oil or gas oil or any heavy oil under proper conditions of volume and expansion or vapor space, temperature and pressure, an uilibrium is produced in which there wil be, with one ratio of expansion chamber to liquid material, quite constantly about 16 per cent of gasoline.- But if during this heating and equllibrium' making operation, I have continuous removal of a relatively small amount of gasoline, more gasqline is formed. The gasoline made under equilibrium conditions I find to be saturated and good being wholly unlike the cracked gasolines Its. removal tends to disturb the equilibrium and. more 'and more gasoline tends'to form as it'is removed.

. In another application Serial No. 800,323, filed Novall, 1913, whereof t e present applicationis in part a continuation, I have described and claimed broadly methods of making synthetic crudeoils containing 'gasoline, from various oils.

As there pointed out, the equilibrium ob tained when a high boiling'oil is heated in a closed container without'permitting esca e of products of reaction depends upon t e ratio of the volume of the original liquid and the capacity of the container. Whatever the ratio between the volume of oil and whl'at t e occupied by the cold oil), there will-always be obtained a'material like crude oil. But the character of this'oil, the equilibrium which obtains in it, will depend very largely upon this ratio. heating a gas oil in a chamber with an expansion s ace 10 times that of the volume of oil use only 79 percent of liquid oilis recovered 5 but the 'gasolinecontained will be 26 per centof the original oil. On the other hand with three times as much oil in having an 8:3 ratio of the liquid space), the amount of liquid oil recovered is 96 per cent but 'it onl contains 13 per centgasoline. Fillingt e chamber half full the recovery is 99 per cent but the yield of gasoline is only 5.5 per cent. The best ratio for the production of gasoline from heavy oil; in operating in this manner is to have an expansion space between five times and two times thevolume of heavy oiltreated. v

To produce the equilibrium in the case of duced suflices.

Fou example in.

find that a momentary-heating pressure of 800 pounds is pro- The same results are obtainedmoreslowly by heating to a. gage pressure of 600 pounds. \Vhere light oils or gases'are treated, the gage pressure maintained cannot of course be relied upon but I find that in this case heating to a temperature of 400 to 600 C. produces the same result. That. is the equilibrium obtains either' at an 800 pound pressure (which corresponds to 400 or 500 C. in the case of heavy oil) or a temperature of 500 C. with a heavy oil so that a gage any oil. Where it can be used the gage pressure is the most convenient index.

Gage pressures up to 2000 -Jpounds have been obtained but the action is not substantially difi'ercnt from that obtained at 800 pounds. The pressures and temperatures required for the equilibrium are, as seen, rather high but I find that the samevresults can be obtained at lower temperatures and' pressures by using an equilibrium accelerat oil. For the sake of dis-' in catalyst in the tribution through the oil it is best to have this catalyst in a colloidal condition. Colloidal metals, such as nickel produced by electrical disifitegration, and colloidal carbon are good catalysts for this purpose. Colloidal graphite of a commercial type is a particularly good catalyst. With the aid of these catalysts an equilibrium can be obtained atpressures as low as 400 of 500 pounds in usinga heavy oil.

After equilibrium is obtained, the'reaction mixture can 100 be cooled to the ordinary temperature and will then generally show a gage pressure of about 120 pounds, this being due to. permanent gases formed.

As to he reason for the existence of these relations between volume of oil and expansion. space, I am not certain and content myself with noting observed results. It is my, opinion however that the necessity -for these ratios depends in some way 'upon producing a particular concentration of the gas and Vapor molecules in the liquidand in the vapor space.

That is, presuming methane to be produced, and it is usually one of the. products, under ordinary pressures it will dissolve in the liquid to a, certain limited extent at any particular'temperature; butat very high' pressures its solubility in the liquid is enhanced. On the other hand, at the high temperature employed much of the oily products tends to go into the vapor formed; to expand into the expansion chainber. And it may tions I employ these liquids reach a critical point. At all events the equilibrium I derim is produced under the conditions recited.

Where, as in the present embodiment of my process, the operation is more or less continuous and the products of reaction remain in the reaction chamber in' large part,

be that under the cond1- the volume ratios are not so fixed in their 'nature since after 'an equilibrium, is estabmust obtain to produce certain results. But

if the chamber be full of hot, compressed gases, vapors and liquids from a preceding operation then a minor withdrawal of liquid products or addition of new oil does not greatly change the conditions within the chamber; that is, the body of oil maintained under heat is, so 'to speak, a dominant pool,,its mass'being relatively so great that a minor addition and a minor abstraction do not materiallymtfect the 20 equilibrium conditions within the chamber.

For example, if a gallon of heavy oil be placed in a 100 gallon chamber and heated up gradually the volatile products of reac- A tion (light oils and gases) would ercapeinto the chamberdeaving the oil nearly free of the same and before the 600 or 800pounds pressure 'isestablished, the oil will have cracked down or even coked. But if the chamber be full of gases and vapors under high pressureand temperature, the volume of oil introduced into it becomes less important. Under these conditions, the volatile equilibrium products do not escape from the oil to such an extent.

' Nevertheless, in the present process I prefor to maintain the volume ofoil around 3/11t-hs of the volume of the treatment chamber; though as stated rather wide variations are permissible once the equilibrium conditions are establishe y In the production of saturated hydrocarbons by breaking down heavy hydrocarbons into light hydrocarbons either by cracking or my equilibrium process theremust be either an addition of. hydrogen or a deposition of carbon. Both results obtain in producing the described equilibrium. 'iIt' is however desirable to restrain the production of hydrogen and 'alsothat of permanent gases, As these permanent gases contain very much more hydrogen than the oil from.

which they are produced it is obvious that in so far as-tliey are formed their production is a -waste,"'not only because of the amount of oil taken to form them, but also because their productionreprcsen-ts a deposition of carbon. Y

I have found in operating with the dem scribed process thatI can obtain low boiling oils fronrheavy oils with very much more economy if I restrict the escape of permanent gases-to the lowest possible amount.

Some escape of permanent gases from the system is advantageous possibly for the reason that some methane and hydrogen are 1 mg in little reactive; they tend to go intothe equilibrium more sluggishly than the other products of the equilibrium forming reaction. They do however have some tendency. to take part in the equilibrium. Presence of methane and hydrogen .is important as aidpreventing formation of more methane and hydrogen: they exercise so to speak a restraining influence. But-.an ex. cess of either while it will disappear in time, disappears slowly; it does, not exercise the. active influence in equilibrium that the other products of reaction "do. I

In'the present invention therefore I heat an oil, which for the present, purposes may always produced and these gases are but I be a crude oil, a distillation residuum, a.-

distillate such as gas oil. or any other heavy oil, under conditions which will allow me toproduce either the described 800 pounds pressure or a temperature of 400 or 500. For thesake of a name the various products of petroleum nature or made from petroleum may be called petroleum materials. By using a certain amount of colloidal under treatment, I can reduce the temperature necessary to about 350 C. or the pressure to about 650 dncedan equilibrium, I slowly remove one of the products of the equilibrium, say the gasoline, without allowing any substantial escape of other products that is, {of the gases produced. Obviously if the equilibrium has maximum amount of gasoline which can pounds. Having pro-q 1 gone on to the production of the exist, if this gasoline be slowly extractednew gasoline-will continuously form in the etl'ort-to reinstate the equilibrium. As previously stated, the equilibrium which 7, obtains is one between all the components of" the mixture being treated; and I regard this as probably true as regards'each individual hydrocarbon as well as regards the mixtures which we termgasoline, kerosene, etc. I do not allow the gases to escape to any substantial extent; thatis 'I vent ofi merely enough gas to relieve undue pressures; pressures above, say, my 800 pounds.

The removal of the gasoline should be at a rate less than the equilibrium forming rate since otherwise I would obtain, as in the ordinary operation, unsaturated gasoline. It is my object to obtain in this invention a gasoline which is saturated and of high commercial grade, needing. no sulfuric acid, or very little,. for refining. iAn advantageous way of gasolineisto perform the reaction in a vesr'el which is locally heated to a' high tempera.- ture and *has a cooler continuation. The

abstracting the gases'as formed will bank. up in the cooler nets.

Evapors is permitted tlme a little gas may be vented oil as the eonliver gasoline. The *at which a particu to speak the gasesand the vapors in the cooler portion of the vessel are merely a gas piston in this action. In the cooler portion of the vessel I- arrange cooling devices which will tend to condense out the gasoline and this liquid gasoline I allow condensed, allowing it'to pass a loaded valve of some type. In so removing liquid gasolineno wasteful escape of the equilibrium though from time to centration of the slowly cquilibrizing gases (methane and hydrogen) tends to increase giving an attendant undue increase of gage pressure. As to the frequencywith which this venting is required, it on the speed of operation since these gases do not refuse to come to equilibrium but are merely slow in equilibrizing.

The gasoline produced is clean and sweet, requiring but little if'any treatment with acid, being saturated in its nature, where equilibrium obtains in the reaction chamber and the withdrawal of gasoline is small as compared with the volume of oil under treat- .ment. The products when they'come into equilibrium appear an outside source production at equilibrium is of course attended with a deposition of carbon whichalso goes into equilibrium with the other materials present. bon under these conditions is deposited. as a. soft br. granular form and does not bake on the heating elements. It may be readily withdrawn with residual oil or liquid prod- In lieu of withdrawing merely the gasoline from thezone of equilibrium, I may also withdraw another product, as-forexample kerosene. In so doing I may provide two cooler zones of'difierent temperatures in the vessel and provide means-for withdrawing liquid from each. .If one of these zones is maintained at temperature between 250 C. and 200 C. while another beyond it is maintained below say100 0., the first will deliver kerosene while the second will dearticular temperature ar product condenses "however of course depends 1n great, measure upon the pressure. The temperatures given are at 800 pounds-pressure;

Or :I may withdraw the whole liquid prod: net of the action as an equilibrized liquid 'or a syhthetic crude oil, the withdrawal being proportional to the introduction of vfresh oil'and the amount of addition and withdrawal being small as regards the body or pool of oil within the equilibrium chamber. The point bf withdrawal of equilibrized liquid from the body ofliquid in the apparatus'should' be remote from the point of introduction of fresh liquid. In making synthetic oil continuously a tubular vessel is deto, escape as it is paratus suitable for the depends mainly .ture or form.

to be saturated bodies. \Vhere there is no addition of hydrogen from But this carsirable for this reason. With a horizontal or inclined tubular vessel, the oil may be, so to speak, equilibrized in transit.-

In the accompanying illustrations, I have shown, more or less dia rammatic'ally, ap-

e'scribed pur oses. In this showing Figure 1 tion of an equilibrium'vessel having a cooler continuation or column adapted for the withdrawal of one or more liquid products of equilibrium; Figure 2 is a similar view of an 2 apparatus ada ted to withdraw equilibrized oil continuous y; Figure 3 is a view partly in vertical section and partly in elevation of a tubular apparatus for the same purpose, and may be regarded as a 4; and Figure 4 is a view part and partly in elevation of a complete plant embodying the-structnre of-Figure 3.

In the showing of Figure 1, element 1 is a still body which maybe heated in any detail of Figure ly in section isa yertica secmanner and may be .of any convenient struc- It is fed with oil through removed inlet 2. Residual oil' may be ening 4 through 3. At its top it has an op communicating with the, chamber-like space in a column or tower .5.- As shown, this column is provided with gage 6 and valved outlet 7 for permanent gases. column is shown a series of cooling coils 8 through which a] cooling fluid, which may be oil or any other high boiling fluid, is sent in the direction shown by the arrow.

As shown there are 'fourof these coils which are meant to be maintained at a temperature decreasing upward. Beneath the top coil is a collector basin 9 having a valved outlet 10.

In the use of this structurea suitable oil is fed into reaction chamber 1 through inlet 2; and, inthis chamber it"is heatedso that the gage 6 will show a pressure of about 800 pounds. By using an equilibriuin-promot ing catalyst in the oil, such as deflocculated graphite, colloidal nickel, etc., the necessary pressure may be somewhatdiminished, down to ,650 pounds. This pressure,'with a corresponding temperature which will be be.- tween 400 and 500 C presuming gas oil to be used, will produce. equilibrium in the whole-system, an equilibrium between the gases, vapors and high boiling oils. Inthis \Vithin the l equilibrium only the, contents of chamber i u 1 needbe considered, since the. gases and 1 should beflso charged as I expansion space. The

5 however do not 3 pressed gas; there is a ten ency towards difto work under 800 to 2000 valved outlet pipe 24.

act purely as a resistin piston of compressure; as by the use of a fusion of vapors upwardly into this column. The inclination of the "tube is only-such as As thesevapors pass upwardly past thevariwill permit a slow flow of oil from the topous coils, their temperature is lowered and end to the lower end 32 while permitting high boiling oils are condensed out and flow the existence of. the vapor space above the backwardly into the reaction chamber or oil from end to end. I The oil in this strucpump adapted pounds pressure.

equilibrium vessel. It the second coil from ture is equilibrized in transit. At the lower the top be maintained at about 200 C. and end is provided an outlet pipe 33 adapted to the top. coil be maintained at, say, 100 0., maintain the level of liquid oil-34, as shown the vapors on passing such second coil will the pipe 33 having a valve 37. In the be very largely gasoline and will be conoperation of this structure fresh oil enterdensed by the top coil, the condensate flowing at 31'fl0ws slowly down and is removed ing into basin 9 whence it may be'removed all-33. During this'passage through the tube from time to time or continuously. By it comes into equilibrium with the gases changing the temperature of ,the top pair and vapors in thevapor space above the oil. of coils somewhat the product will be rich Th t i t about thljeeelevenths full in gasoline and kerosene. Other fractions of liquid oil.

may be simultaneously produced by provid- In F igure 4, element '35 is a storage tank,

ing the other coils with basins and outlets 36 i it h g Pressure a dem pump, 7 i at 10 and'lO". From time to time '01- cona reducing valve and-38 a pipe leading from tinuously a portion of the permanent gases Outlet pipe 33 to storage tank 39. may be vented through 7; Q In the operation of Figure 3 the gases As described the operation may be conf m re al o Vented with the outflowing tinuous, o'il being m d i th o h-2 d liquid through 33, gas and liquid passing gasoline being formed in and. removed from 9 a t nat ly 01 ogether. The term peb i 10, a troleum oil as used herein includes all In the structure of Figure 2'element 20 analogous oils of mineral origin, such as is a still retort or equilibrium chamber'of 0118 ed from the fiil of shale any desired size and heated in anydesirable and the way. At its top it is provided with oil W 101111111 inlet 21 and g 22, Withi it d p d 1. The process of converting petroleum an il ithd l i 23 ti i t 0118 which comprises establishing and mam- In the operation of this structure oil is thelTeflom n Such heat and Pressure as fed in throug'h21 and joins the liquid pool will p e equilibrium in such bod and 25 i th b tt f th apparatus A th during the maintenance of such equili rium liquid products of equilibrium collect in 25 Slowly Withdrawing the cll Products Of they rise above the inlet of 23 and escaw and w y a iug fresh 011- through 24. The upper'part of the retort The process of convert ng petroleum is filled with vapors and gases and thelower 1 i h comprises establishing and malnwith liquid oil, both being in-equilibrium. tamlng a b y of p o u 011 and vapors Oil being constantly fed i under very hi h therefrom in the presence of a catalyst and pressure and the reducing valve on 24 being under f h 1 Pressure as W111 B set to somewhat lower pressure, equilibrized q eqlllllblflum Such 9 y f durmg liquid oil flows outcontinuously. Any exmalntenance of u equlhbnum slowly cess of gases formed alsoautomatically finds Withdrawing liquid Products f equilibrium 3 outlet in the same way. It is best with this fi slowly addmg hresh form of apparatus to have the depending h P i y k P tube 23 about 0.75 the length of the retort. P Q e ns d This makes a liquid body filli n a taininga body ofoil in contact with its own quarter of the capacity of the chamber vapors and under such heat and pressure whereas elsewhere I have found the ratio as W Produce e m between, p to be better about 3:11. In this case the Vapors u v and durmg Such m difl'erence is probably due to the fact that tenance W l' w converted 011 from one point in such body-and slowly add;-

the lighter hydrocarbons are in the vapor p q spaceand the oil pool contains only the oils fresh 011 to another Polnt 111 Such y not volatile under the high temperature and pressure prevailing. 4

In the structure of Figure 3 element 30 is a very heavy steel tube which" .the traveling equilibrium.

4. The process of converting petroleum At the upper end is'inlet' tube 31 -from heat and pressure as. will produce equilibwhich oil may be introduced under pump rium therebetween and dur ng such ma nat a rate insuflicient to disturb materially b oils which comprises establishing and mainheated in any manner as by a lead jacket, taining .a body of oil as a long column'in vflame heat, etc. It is set at a slight'angle. Contact W Its Own ap s n er such 5. The process of converting high boiling petroleum oils which comprises establishing and maintaining a body of such oil in a roomy chamber at a heat and pressure which will produce equilibrium between the oil and its vapors and continuously supply- 7 ing fresh petroleum material and withdrawing liquidproducts of equilibrium, such supply and withdrawal being at a rate insuflicientto disturb the equilibrium prevailing in such body.

6. The process of converting high boiling petroleum oils which comprises establishing and maintaining a body of such oil in a roomy chamber at a-heat and pressure which will produce equilibrium between .the oil and its vapors and'continuously supplying fresh petroleum material and withdrawing liquid products of equilibrium, such supply and withdrawal being at a rate insuflieient to disturb the equilibrium prevailing in such body, the volume ,of said roomy chamber being less than ten times the volume of Oil therein and more than twice as great.

7. The process of converting heavy petroleum oils "substantially free from light oils into a product containing light oils which comprises heating such a heavy oil in a roomy chamberunder a heat and pres sure producing equilibrium conditions therein and during such heating slowlyfeeding fresh oil into said chamber and slowly withdrawing? equilibrized liquid products therefronr at a rate insufficient to disturb materially. the traveling equilibrium.

8. The process of producing an equilibrized petroleum oil containing gasoline from a heavy petroleum oil. substantially free of gasoline which comprises establish- .inga relatively shallow layer of oil in a horizontal tubular chamber, heating such,

oil until a pressure of 600 pounds or higher is attained, maintaining the temperature at this point and during such maintenance slowly withdrawing liquid oil from one end of said chamber and. slowly supplying new oil to the other 'end of said chamber.

'9. The process of treating petroleum materials which comprises heating a body of such material to a high temperature under high pressure and in the presence of vapors derived from the said material until an equilibrium obtains, maintaining said body of material at such heat an d pressure as to substantially maintain such equilibrium and during the maintenance of the equilibrium slowly abstracting fromflthe reaction zone liquid products of such equilibrium.

10. The process of converting petroleum oils which comprisesestablishing and maintaining a body of petroleum oil, in contact with vapors thereof, under such heat and pressure as will produce equilibrium be tween said oil and said vapors, and during the maintenance of such equilibrium slowly withdrawing products of such equilibrium and slowly adding fresh oil.

11. The process of converting high boiling petroleum oils which comprises establishing and maintaining a body of such oil in a roomy chamber at a heat and pressure which will produce equilibrium between the its vapors, continuously supplying fresh petroleum material, establishing a plurality of condensing zones of different predetermined temperatures-and withdrawing liquid condensation products from at least one of the said zones, the supply and withdrawal of material being at a rate insufficient to disturb the equilibrium prevailing in such body.

13. The process of converting petroleum materials, which comprises heating a body of the material to a vaporizing temperature in excess of 350 C. while under pressure sufiicient to retain at least some of the con stituents in liquid state in contact with vapors then maintaining said liquid and va- 1 pors at such temperature and pressure as to maintain an equilibrium of constituent hydrocarbons, and abstracting from the reaction zone portions of products while supplying new material.

14. The process of converting petroleum materials, which comprises subjecting a body of the material to a vaporizing temperature in excess of 350 C. while under a pressure sufficient torretain at least some of the l constituents in liquid state in contact with vapors, andmaintaining an equilibrium of constituent hydrocarbons, While. abstracting portions of the products and supplying fresh material.

15. The process of converting petroleum materials, which comprises heating a body of the material to a vaporizin temperature in; excess'of 350 C. while under a pressure suflicient to retain at least some of the constituents in liquid state in contact with vapors and maintaining all constituents under such temperature and pressure as will produce equilibrium in the constituent hydroearbons, and continuously withdrawing 10 stituents in liquid state in contact with vapors, andmaintaining all constituents under such temperature and pressure as will produceequilibrium in the constituent hydrocarbons, and simultaneously wlthdrawing products of equilibrium and supplying 17 .freshpetroleum material.

In testimony whereof, I alfix my signature.

WALTER o. sNELLING.

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