US1585573A - Method of electrochemical treatment of unsaturated hydrocarbon compounds resulting from the cracking of oils - Google Patents

Description

1,585,573 D. L. THOMAS TURATED HYDROCARBON RESULTING FROM THE CRACKING OF OILS Ma 18 192s.

METHOD OF ELECTROCHEMICAL TREATMENT OF UNSA COMPOUNDS Original Filed April QuinIIiMqIuIqIuInlullillglqlnlnlnlulnlnlgllnlnlul INVENTO $610124 A7 7/01 ATTORNEY l Pate ted 18,1926.

PATENT orsica;

mm L. :rnomns, or NE YORK, N. Y.

POUNDs RESULTING IROM THE ,CRAQKIN' G'OF- OILS.

Original application filed April 24, 1919, Serial No. 2a2,425. Divided and this 9, 1925. serial-r0. 7,886.

I This invention relates to the electro- .a detriment, whils t during recombination,

chemical treatment of unsaturated hydro-r asit favors reunion of the cracked products,

carbon compounds resulting from the heat cracking ofoils and has for its objects the ,6 stabilization --of such compounds through the hydrogenation, polymerization or recombination thereof whereby the yield of condensable liquids is incrasedand valuable light hydrocarbon liquids of superior 1 quality to that ordinarily produced by the usual high pressure cracking process can be obtained by' the simple distillation of the resultant products without necessitating expensive acid refining treatment. a In my co-pending application No. 292,425 for process and apparatus for converting high-boiling oils orhydrocarbons into stable low boiling oils or hydrocarbons filed'April 24, 1919, of which this applicationis a true division, there is described a novel method and apparatus for the pyrogenetically cracking of hydrocarbons by heat and pressure for the purpose of producing unsaturated hydrocarbon compounds which are suitable for being subjected to the electro chemical treatment hereinafter described.

As stated in said pending application, the amount of heat required is that which is necessary to furnish the expansive force 3 needed to bring about rupture of 'the original hydrocarbon molecule, whilst pressure is necessary to force together the resulting nascent reactive products into more concentrated and intimate relationship so that reactions involving new molecular arrangements can thereafter take place in a. second and preferably separate stage of the proc- I ess. The reactions of this last 'stage of the process are greatly facilitated by the action 40 of the electric current, which plays the part 1 of a catalytic element, .aflecting the timefactor of the reaction andmaking possible the accomplishing of results that are unattainable-by other and less energetic means. As all cracking operationsvrequire more or less mechanical force for their development, it iscustomary to obtain this force from the expansive power of the 'oil-vapors developed under pressure. Thepressure in this last mentioned case,-when present. during the decomposing stage ofrthe process, naturally opposes the expansive force need ed-to bring about rupture of the hydrocaritlis a sinequa-non' of operation.v

applieationfiled February From these facts I have ascertained that the cracking operation should take place-in the following series of steps:

cient working force to operate the ap-.

paratus.

2nd. Cracking ofthe oilvapor at higher temperatures, for example at from 500 to 800 0., under low pressure to produce.

chemical dissociation. 3rd. A condensation of the cracked products, under high pressure in order molecular recombination.

under pressure, to the silent electric dis charge or electric corona, either Before or after condensation to the liquid state, to produce hydrogenation and polymerization.

4th. Treating-the cracked products While At present there are at least three-recognized standard methods of cracking oils by means of heat and pressure, each capable of illustration by a type.- First, the so-called Burton-process, consisting of heating a large body of liquid oil in a large tank or still, and condensing the vapors generated- Second, .the socalled Rittman-process, consisting. of heatj mg oil-vapors under pressure, in a large therein under pressure.

(12 inch) tube and then condensing the cracked products so produced'nnder pressure.

Third, the sol-called Hall-process, which consists of heating the oil in a long coil of small bore pipe, (1 inch diameter and 600 feet long) releasing the pressure so produced, by expanding thevapor down to atmospheric pressure in a large tankor. chamber and then" again recompressing the gases andvapors by means'of a mechanical compressor, in order to polymerize them, and

then final-ly'condensing the resulting prodnets to liquid under pressure.

,To'. these may be-added a fourth type, as exemplified in my sai'dcgpending application, wherein an oil, as fuglgoil of, 850 S. G. is vaporized under pressure and the vapor soIgenerated, passed into a region of low pressure. High temperature is then applied bon .molecules, hence, at this point it is to the vapors in this region of low pressure to favor pressure for recombination and polymerization.

. Finally they are subjected to the action ofthe silent electric discharge, in this region of high pressure, either whilst" in the vapor state or after condensation to the liquid state,and finally. condensing and removing the finished product. All this to be ac-' comp'lished without the use of mechanical Oneof the features of this invention is a being in a liquid state.

Fig. 2 is also an elevation partially in sec-.

pumps or compressors.

The specific exa'mpleof a one tube mstaL .lation is fully set forth-and described in .the following specification and drawings forming a' part thereof in' which Figure 1 is an elevation, partially 1n section of a form ofthe apparatus wherein the cracked products are first treated in a digester, and are then submitted to the action of a corona or silent electric discharge, either direct or alternating, the treated p'roducts tion of a form wherein the di'gester is dispensed with its place bein taken by an electrical treating chamber a apted to function as adigester and polymerizer, by acting on all of the cracked products whilst existent .geo.

in the form of vaporsand gases before being1 condensed to the liquid state. Figs. 3' an 4 show longitudinal and cross sections of the pieces of iron pipe used in the digester.

meansby' which the unsaturated hydrocarbons inevitably found in all products that.

- are cracked by heat maybe permanently deposits a gummy resinous residue very instabilized. Thesecompounds have a very deleterious effect on motor-fuel produced by cracking as such fuels in the course of time juriousto the action of the valves of internal combustion engines. The. removal of such products by meansof sulphuric acid is 'a' very serious problem of the refinery, and

I one that so far has defied a satisfactory solution on account of the large loss of valuable material involved. These products if *they could 'be stabilizedwould form a very valuable-addition tothe fuel itself, adding greatly to its thermal or heating capacity. It is purposed to show herein how this result 7 can be accomplished. As a preliminary to 4 both alternating and direct, on various sat-. "'urated and unsaturated hydrocarbon compounds leads to the conclusion, that as a a presentation. of the means to be used fdr this purpose, it may be stated that vthe effects are predicated on the experimental results attained by such men as J. N. Collie, H. Jackson and- D. Northall Lowrie, and F. Skaupy working with the electric current in the form of a corona or silent electric dis- ,charge through hydrocarbons, wherein it is shown that the action of electric discharges,

general rule, saturated compounds aref broken down to simpler molecules, whilst un-. saturated-compounds (such as ethylene and" olefines) I are converted into complex polymerized substances,'thus, in the case of parallin derivatives the general tendency is for unsaturated bodies to give polymerized varij etres under the influence of the silent'discharge, whilst saturated compounds, under similar conditions, yield substances of sim- 7 pler structure. At the same time it must be.

. pointed out that the silent electric discharge under proper conditions (such as whenhydrogen or gases containing hydrogen are prescnt) has the power to bring about hydro- 0 genation of unsaturated compounds, this has been pointed out by A. de Hemptinne in his U. S. Patent No. 797112. Considerable use -is made of this last feature because in the method outlined herein, it is proposed to pass the gases generated in cracking the'hy drocarbons, into the electric field along with the condensable hydrocarbons or the liquids derived therefrom, the wholevbeing treated in such manner that the gases, and the con--a0 densable vapor ,or the liquid are brought into intimate contact with each other whilst being submitted to the action of the electric efliuvia. The result ofthe action will be to, bring abouta union of more or less of these gases with. the vapor'or liquid, along with polymerization of unsaturated compounds, whether existant in gas, vapor or liquid, thus materially increasing the yield of condensable liquids. Moreover it will'be found that 101 the resultant liquids are, perfectly stable,. the ,double-bonds of the unsaturated moleculeshaving been satisfied or eliminated by combination, thus-,'stabi lizing the product.

-\V hen purified by a further simple distilla- 10% tion the liquids are ready for use.

.One method of carryingout the process is illustrated in Figure 1. Here an electrical coronaor silent electrical discharge is created directly in 'the body of the liquid hy- 11" drocarbom To many, the idea of producing a corona discharge directly in a body of liquid oil, will seem revolutionary, the phenomena however, is well known to elec-- trical engineers; see articlesby F. W. Peck, 11 Jr., in The General Electric Review, vol. 18 -1915 page 821 and-by W. S. Moody and p G. Faccioli in Trans. Amer. Inst. Electrical Engineers vol. 281909' page 769'.

In its way electrical corona mod is quite 12 as distinct a phenomena as'in.v gases. or. air,

The d ielectric strength of oil, that is to it tional to pressure.

say, the disruptive gradient or voltage required to bring the ions upto an ionizing Collision velocity, seems to'be fairly low,- and according to F. W. Peck, Jr., is about 36 kilovolts, therefore it may be said oil hasa Y low dielectric strength in bulk. n

Referring to Figure 1, the pipe a is adapted to receive cracked products while still under the final pressure and at the temperatures to which they were subjected in the final space or chamber of the cracking unit of the refinery and without previous cooling of the said-products, such for example as the lower diverging Venturi mouth piece of the apparatus (not shown) described in my co-pending application aforesaid.

It is to be understood that the object of the digest'er .7) is to treat the hydrocarbon material by exposing it, to large surfaces 1)" by which it is naturally adsorbed, whilst the speed of travel of the vapors is reduced to a minimum. Such surfaces exert a catalytic or some similar effect on the cracked material which is in a highly reactive condition, bringing about hydrogenation, polymerization and recombination of the nascent fragments of the original hydrocarbon molecules into new molecular arrangements. This action is of course assisted by pressure, because, according to the law of mass action, reaction velocity is proportional to concentration and concentration is directly propor- Surface action has a great deal to do with the effects produced as nal of Physical Chemistry, June 1918, page is in liquid or gaseous state when brought is pointed out by Professor Wilder Bancroft in a Note on contactcatalysis J our- 433, wherein it is shown that the equilibrium and velocity relations of physical substances is markedly altered by adsorption, much freer play being given to physical and chemical forces thereby. Whatever the cause may be, the action is unquestionable,

being more cumulative than instantaneous and it takes placewhether' the hydrocarbon into contact with the material.

It appears that two entirely'difierent reactions are involved in the; formation 'of light hydrocarbons. Thefirstone involves slitting of saturated bodies into saturated and unsaturated, parafins; and olefines of lower molecular weight resulting, with the splitting out of hydrogen, and consequent increase in volume of cracked produbts. Diminished pressure facilitates and accelerates this stage. The next step, however, requires the condensation and hydrogenation of the unsaturated bodies, and pressure naturally favors this. It is true that hydrogen may split out also at this point, but even so, condensation and hydrogenation is difficult to effect under diminished pressure, therefore sufiicient pressure must be provided to effect this condensation since the natural tendency of pressure is to force homogeneous Figure 1, shows how this may be carried out.

Here, in this method the condensed liquids along with the non-condensable gases, are led into a receiving tank space, 64, formed usually in the upper part of the treating receptacle, 65, by means of a pipe 66, and valve, 67, that connects with the condenser 68. The receptacle 65, preferably consists of strong steel tube having an inner enameled surface 65' of glass, porcelain or other dielectric material, the dielectric surface serving to prevent danger of a short circuit when the oils are very bad and contain electrically conductive material, *at the same time the dielectric is-useful insuring a uniformly distributed electrostatic field. The upper portion of the receptacle, 65,is closed by an insulating stopper 7 0, thus separating and hermetically sealing off the tank-space 64 from the main body of the receptacle 65. The main body of the receptacle is provided with an outlet tube 71 near its upper end, for the escape of the treated gases and liquids to, thestorage tank and recirculating gas-line 91. A11 electrically insulated metallic tube or pipe 72 extending from the interior of the tank space 64 into the bottom of the main receptacle 65, serves to deliver the liquids'and gases discharged into the space 64 from the condenser to the bottom wardly outside of the tube 7 2 to the pipe 71.

-' This insulated metallic tube 72 constitutes the inner co-operating electrode to theouter walls .of the treating chamber 65 which form the outer electrode. As indicated,

this inner electrode is preferably provided with sharp projections, formed by thin metallic discs J spaced short distances apart by washers e of smaller diameter, thewholebeing held togetheron the pipe 7 2 by suit-. v

The con struction is such that this inner electrode is able screw-connections and nuts.

separated a greater distance from the outer' electrode, at its ends, than at the region where the projections are provided and where the electric action takes place. The oils and the gases in thorough admixture therewith, on being discharged into the lower part of the treating chamber, rise to the v 4 discharge tube 71 and in so doing pass 90 by a dynamic are following a spark-over, as v venting danger to operators from electric shock. The positioning of the electrodes, .one within the other, is an advantageous one, as it gives a very dense electrostatic field of high gradient near the inner electrode,. but of relatively low gradient at the outer electrode or wallof the treating chamber which facilitates the production of the corona discharge. 4

" J The liquids after passage through the treating chamber are submitted to further simple distillation treatment, to remove polymerized resinous products and are then ready for use. The advantages of this a method of treatment over that requiring the use of sulphuric acid, with its large attendant loss of valuable material at once recommends the method to the attention of those interested in securing a rapid and economi- .cal' method of treating crackcd'hydrocaricons to render them suitable for the market. Although I have disclosed a suitable form of apparatus for practicing the invention, I do not limit myself to these special devices or constructions herein specified, as I believe it is broadly new with me, to utilize the effects of, passing a high potential electric current through a body of liquid hydrocarbons in order to effect the hydrogenation, polymerizationand synthesizing of the unsaturated compounds existing in such cracked oils as specified above as products suitable for treatment.

- In the form of the invention disclosed in Fig. 2 the important function of the digester of Figurel is dispensed'with, its place being supplied by' an electric polymerizer, adapted'to function both as digester and olymerizer'by acting on all of the cracked hydrocarbons while they are in the .vapor state. This arrangement has certain advantages due to the fact that not alone is the plant rendered more compact, but the corona discharge'itself issomewhat easier to produce and maintain in vapors and in gas es than it is in liquids.

In order to make the construction plain, it

may be said that the cracked products are conducted by the pipe 0 to an electrical treating chambers as shown, consisting of a steel tube about 12 inches "internal diameter 7 and 15 ft. high. To its base is fitted a conical extension or sludge-box 78, having an 'automatic-float-controlledsvalve 78, for removing liquid residues, as previously exa plained, and-which maintains the liquid level at the point 7 8"7 8",.

Suspended in the tube 0 and electrically insulated therefrom, isa high tension discharge electrode 79, formed of a inch steel rod, having thereon in equally spaced relationship, thin metal discs about 3 inches in diameter and spaced apart by metal washers 1 inch in diameter and inch thick. To the top of the electrode 7 9 one wire 80, of a high tension alternating current electrical transformer 81, is attached, the other wire 82 of the transformer being grounded at To the base ofthe electric-a1 treating chamber and in electrical contact therewitlr at the point 84, there is attached a Wire 85, which in itsturn is grounded at 86. The objcct being to avoid danger of electrical shock when the-high-tension transformer is being operated. i

By causing acorona discharge to take place between the walls ofthe tube and the central electrode,"oil-vapors on being passed -thro1ighthis tube are subjectedto a series of intense electrical fields of high gradient near the central electrode, provided the edges of' the discs, and the unsaturated products contained therein are rapidly polymerized and built up according toprinciples already enunciated. The tube 0, should have a heat insulating jacket 1), around it to prevent loss of heat and consequent undesired c011- densati'on at this point.

the vapors pass to the water-cooled condenser (58, by means of a pipe 87, and here the cendensable portion of the cracked products is reduced to liquid formand flows into the storage tank90 the.non-condensab-le gases escaping by way of the connection '88, to the pipe line 91' to be returned to the system for recirculation therethrough forcarnying out the various functions already specified.

The part played by electricity in this proce-jas should be clearly understood, as it is important to grasp the idea that the current is not used for the purpose of decomposing the hydrocarbons, such decomposition as occurs being merely incidental, the main purpose and object in View being the hydrogenation and. polymerization of the cracked-products,

so as to completely stabil'ize'the resulting product. of the reaction. This the current as has been pointed out above.

does in a very thorough and rapid manner I am perfectly familiar with the fact" that it has been proposed to use the electric current as a'meansof'decomposing hydro- Y carbons in order to produce lower-boiling.

products, theuse of direct-current for this purpose having been patented by J H. Robertson (U.- S. 'Pat.'No. 1238339) and the use 'of' alternating-current having been patented by. L. B. Cherry (U. S. Pat. No.

1229886) But so far as my knowledge goes, it has never been proposed to use the elec tric current as a means to bring about hydrogenation and polymerization of the cracked products, after the cracking operation itself has been completed by heat and pressure in the usual manner. This forms a clear and distinct line of demarkation between this method and the processes referred to above. In the one case it acts as the cracking medium, in the, other case it acts as the synthesizing medium. This use of the current com pletely eliminates the gummy material deposited by most cracked gasolenes' and which is due to a slow polymerization of the unsaturated compounds which they contain. These compounds are completely polymerized once and for'all by the current and are then, after condensation, removed by a simple distillation of the final product. A material saving inthe way of refinery treatment is thus efi'ected and a much higher grade product produced.

Under the influence of the pressure and the action of the electric current, recombination, polymerization and hydrogenation rapidly occurs in the cracked products, which are then passed to the condenser for reduction to liquid form whilst still under pressure.

The exit or operative pressure on the products from the previous cracking operation described in my said co-pending appli' cation which are introduced through the pipe at will be about 135 lbs. per square inch and the temperature will vary between 500 C. and 800 C. for example, between 500 C. to 600 C. where gasolene is desired or from 600 C. to 700 C. where aromatic hydrocarbons are desired.

The digester has already been described, the only remarks to be added are that it is provided with a removable cap, 62, so that the filling material can; be removed at any time. Further an automatic sludge-valve 63, is provided which keeps the liquid level at 63.63, as shown. .1

' The digester b consists of a, stout steel chamber 24 inches internal diameter and 12 feet high, filled with short pieces of .1 inch iron pipe, such as illustrated in Figures 3 and 4. V f

Having thus described my invention, what I claim and desire to obtain by Letters Patent of the United States is:

. 1. The process which consists in subjecting the pre-cracked material, resulting from subjecting high boiling point hydrocarbons to a heat and'pressure cracking processin which the principal portion of the heat employed isgenerated without subjecting thematerial to theinfiuence of a silent electric discharge, to the influence of a silent electric discharge of sufficient intensity to materially polymerize. such materials, wheieliy the same drogen is taken from the gas and caused to pounds resulting from heat cracking of oils,

ated state and of a gas relatively rich in hybons whereby hydrogen istaken from the are substantially stabilized and otherwise improved.

2. In the process of cracking hydrocarbons and then of hydrogenating pre-cracked unsaturated hydrocarbon compounds whilst in the dissociated state, the step which consists in subjecting a physical mixture of such compounds and of a gas rich in hydrogen to the discharge of a high tension electric current, thus causing rearrangement of the molecular. structure of the hydrocarbons whereby hydrogen is taken from the gas and caused to unite with the unsaturated hydrocarbons to produce stable saturated hydro-v carbons;

3..In the process of cracking hydrocar bons and then of hydrogcnating pre-cracked unsaturated hydrocarbon compounds whilst in the dissociated state, the step which consists in subjecting a physical mixture of such compounds and of a gas'rich in hydrogen to the discharge of an electric corona, thus causing rearrangement of the molecular structure of the hydrocarbons whereby hyunite with the unsaturated hydrocarbons to produce stable saturated hydrocarbons.

4. The electrochemical process of treating pre-cracked unsaturated hydrocarbon. comdrogcn to the discharge of a high-tension electric current, thus causing rearrangement of the molecular structure of the hydrocargas and caused to unite with the unsaturated hydrocarbons to ,produce stable saturated hydrocarbons. 1 6. The process of treating pre-cracked h drocarbon compounds, resulting from til the cracking at a cracking temperaturef'of high-boiling point hydrocarbons, which consists insujecting such products while in a nascent state and comprising a mixturebf.

condensable and non-conde'nsable vapors and gases, the latter rich in hydrogen, to the action of an electric corona inorder to hydrogenate and polymerize the condensable portions'thereof. w -7. The process which consists in subjectingthe PrG'QTaCkGdPIOduCtS from the cracking 1 of high-boiling point hydfocrxaonslat a cracking temperature and While in-the presence of the uncondensztblegases,- rich in hydrogen, resulting fromsuch "'previous' treatment, to the action of an electric corona;

for a sufficient period o'f'time to effect sub-.

stantialhydrogenation and polymerization of such cracked products.-

8 The process of improving pre-cracked ""ussmu'rs corona .in order to polymerize and hydrogenate the same.

gned at New State of- New' York this 7th of February DONALD L. THOMAS.

York, in the county and

Images