US1658116A - Process of cracking oils - Google Patents

Description

Feb. 7, 1928. 1,658,116

J. C. CLANCY PROCESS OF'CRACKING OILS Filed Sept. 2, 1922 3 4 d /70112121 l4 yanzd Seal Dwerzifin Betented Feb. 7, 1928.

"UNITED STATES PATENT J'OHN COLLINS .CLANGY, NEW YORK, El Y.

rzaocnss or ,onacxme oILs.

' Application filed September 2, 1922'. Serial mi. saaoaa.

example, kerosene, crude oil,-"-coal oil;' tar oils, 'Lorj otherhydrocarbons is "heated to a cracking temperature, a splitting up of the "heavy -molecules into molecules pf lower molecular weight together with the generation of hydrogenand formation oftar and free carbon takes place. Ithas been recog- 'nized that-the cracking action is facilitated by the presence ofcatalysts, such for exam-v p1e,,asl metals like nickel, cobalt, copper, silver, palladium, chromium, and man anese orthe oxids of these metals. processes comprises passing the oil or oil vapor over the surfaces of metal" catalysts which ha've been formed into regular or irregular bri uettes, balls, tubes, screens, fragments of eat, resisting material coated withmetal or with some metal compound which can be reduced to metalby theaction oft-he hydrocarbon. These'catalytic masses above referred to are introduced into tubes or pipes made of iron or earthenware heated of the hydrocarbon to be cracked. However, the above mentioned and other similar processes heretofore suggested sufier from the difiiculties involved in keeping the catalytic surfaces free fromdeposited soot or carbon whichcoats the contact material and brings about. cessation of the'catalytic activity of the contact, material. It is noted in" this connection that aside fromthe deposition of soot, the sulphur present in-the hydrocarbon vapor or oil being treated attacks the metal catalyst to render it non-active, commonly termed poisoned." Again, the hydro- .gen. set free by'the thermalgdecomposition of the hydrocarbon isi'preventedfrom functionin to hydrogena'te thenn'saturated hydrocar ons formed'in the process owing to i the coating of the catalytic surfaces with :carbon and the formationfof metalsulphides as aforesaid,

One 0 such to about red heat and traversed by the vapor was We ten body containi a cyanogen compound in presence of a so h d catalyst. The pm sees,

more specifically, is characterized b the fact that the molten body and the hy rocarbon to be treated are contacted with each other in a reaction zone or chamber in the presence of and contact with solid-masses of catalytic material which retain their physical form and position and serve notonly as a catalyst forthe cracking reaction, but also as supporting and distributing packing units for the contacting of the mo ten body with the hydrocarbon. The p -.characterized by the fact that thiocyanates upon a hydrocarbon oil or vapor with a in'olrocess is further a are formed by the action of the cyanid con- 7 v tamed. in the molten body with the sulphur contained in theehydrocarbon material be;

treated. This action of the molten cyanid forming thiocyanates with the sulphur contained in the oil keeps the catalytic surfaces free from catalyzer poisons. Still a further characteristic featureiejiiithe process is; that the cracking is ejffec'ted'inla reactionzone or chamber to whioh the-Iiriplten material, such for example a--molten mi1t'- ate is sup lied througha trapped inletland from whic the molten reaction productsstoje Y, ether with the carbon soot) and 'unvapolf-z-l lzable hydrocarbons at t 0 temperature em ployed is discharged through trapped outlets, the oil or hydrocarbon to be treated being supplied to and its decomposition prod- 7 jure-sof sodium cyanid .and sodium fiijocyaa reacting conditions of the-process. Another characteristic of the processresides' in the use of the molten material to hold. in sus-v pension the carbon separated. in the process of cracking. This property of the molten cyanid containin'g'material to carry con-' siderable or substantial amounts of carbon in suspension together with its desulphurizing actlonon the metal sul hides formed on the catalytic units keeps t e catalytic surfapes of said .units free checkz-cata'lysis' The obtmnment-ofthls reeeult byithe me of said molten material allows the hyfdrogen present injthe decomposition prodiie'ts or the hydrogen or-hydrogen containing gases which matyBbe im' tro uced into the reaction zone toge "the hydrocarbons t0 be treated, the oppor r with tunity of hydrogenating the unsaturated hydrocarbons formed in the cracking operation thereby producing substantial amounts of saturated lighter hydrocarbons. Further features of this invention will appear here inalfter as the invention is described in detai Fused sodium cyanid in admixture with sodium thiocyanate is fed into a closed furnace shaft through a sealed inlet on to a tower filling of packing units formed of or comprising the catalytic agent heated to a temperature of 400 to 600 C. or higher. The molten material flows or trickles downwardly through the catalytic packing units and a flow of the hydrocarbon to be treated is supplied to the furnace shaft at or near the lower end. In case the hydrocarbon is supplied in the liquid phase it is immediate- 1y converted in part at least into the vapor phase, that is, the part which will vaporize at-the temperature maintained in'the furnace ascends while the higher boilingpoint or unvaporizable hydrocarbons will be discharged together with the molten material out through the trapped outlets. The lower end of the furnace is closed to the atmosphere and is provided with sealed outlets for the molten reaction products as aforesaid. At the upper end of the furnace shaft is an outlet for the gases and vapors formed by the treatment in the reaction zone. Molten material containing sodium cyanid and the oil or hydrocarbon vapor with or without admixture of hydrogen or hydrogen containing gases are continuously supplied to the furnace shaft at top and bottom respectively and the gases constituting the hydrocarbons formed in the cracking process and the molten reaction products are withdrawn from the furnace shaft at top and bottom respectively the temperature of the furnace being maintained by external heating of the retort by the burning of fuel. Obviously of course the temperature of the furnace may be maintained by the passage of an electric current through a resistor embedded in l the packing units, or by using the packing thiocyanate are the preferred cyanogen comunits as a resistor if cheap electrical energy 1s.ava1lable. v

Sodium cyanid in admixture with sodium pounds employed in the process principally because they give satisfactory results and are inexpensive. Instead of sodium cyanid I may employ other alkali metal cyanids, such for example, potassium cyanid, alkali metal thiocyanates, as for example, sodium thiocyanate or I may employ mixtures of sodium thioc anate with alkali cyanids. In working te process however the discharged molten material contains considerable amounts of sodium thiocyanate especially when working with oils of high sulphur content. This material after removing the carbon by filtration of the discharged molten body is used over and over again by replenishing same with fresh sodium cyanid.

I have found by numerous tests that the best results are obtained by using a mixture of 25 parts of sodium thiocyanate to 7 5 parts of sodium cyanid as the molten material in the cracking of hydrocarbons, by using this proportion the melting point of the cyanogen compound mixture is reduced to 400 C. or lower. The melting point of sodium cyanid by itself is around 587 C., the melting point of sodium thiocyanate approaches 300 (1., it is evident that a wide range ofmelting points can be obtained by varying the proportion of the above mentioned compounds. The addition of small quantities of alkali salts such, for example, sodium carbonate, potassium carbonate and the like influences the melting point considerably. 1

gen bearing material discharging from the furnace exceeds 25% to 30% by weight it is desulphurized by adding or fusing it with iron at a high temperature to remove the sulphur in the form of iron sulphide, the fusion productfiltered from the iron sulphide can be used again as the contacting molten body for use in the process.

Among the hydrocarbons which may be used in the cracking process for the production of gasolene or a gasolene substitute are the hydrocarbons of the parafiin series such as crude petroleum, kerosene, coal tar oils, tar oils, shale oils and the like. I have obtained excellent results by spraying crude Mexican petroleum oils directly into the reaction zone in company with hydrogen and also with hydrogen containing gases such, for example, the uncondensable gases obtained after condensing out the liquid hydrocarbons from the cracked decomposition products. I have also obtained excellent results by spraying into the reaction chamber finely pulverized solid shale and also finely pulverized coal. contemplates only the use of liquid hydro carbons such as those above referred to and I merely mention the treatment of material containing solid hydrocarbons to show the wide applicability of the process.

With regard to the catalytic material for the process I have discovered that there are a great variety of materials which may be used. and there are a. number of ways of forming and handling catalytic material. The catalytic material serves two purposes in the rocess,

motes the hydrogenation reaction, an

- mad-fie first, itjpromotes the cracking and; ydrogenation-refaction, and second, it

-.serves as a distributing contact surface for the reacting materials. [The catalytic material must therefore be a material which romust be capable of withstanding the temperature and the action of the molten cyanids 1 without fusion or disintegration.

The catalytic material is employed in the physical form of packing units of either ir-' regular or regular shapes which may be associated as a packing material in either promiscuous or a symmetrical arrangement.

' The packing-units may be formed wholly of one catalytic material-or a mlxture of two or more catalytic materials or they may comprise one or more of the catalytic materials mixed, with or bonded by other non-catalytic substances, or the units may be formed of material-capable of being converted to a catmass or an alloy. of

units of cobalt and, cop

as aforesaid in alytic material. For instance, units may be formed or'molded from a single metal in two or more metals capable of -forming the said units.

Metals which I have found to possess the required characteristics, that is, the capability' of catalyzing or hydrogenizing the unsaturated hydrocarbons in presence of a molten cyanogen compound are nickel, co-.

- balt, copper,

chromium, tantalum, silver and palladium. fWhen using the metals above referred to as packing units 1 prefer to shape them into forms of packing units such as the so-called Raschig rings about one inch in diameter. I also prefera mass or column of catalytic packing'units comprising a. plurality of layers of different 'cata lytic materials. For example, assuming that the distance from the bottom of the furnace is ten feet in height,.the lower three feet is filled with copper packing units, the. next three'feet is filled with an. equal mixture of per,- the next four feet is filled with istraightitnickel packing units. The packing unitgfare preferably the form of Raschig rings about one inch in diameter. The purpose of ethe different catalysts in the reaction zone is to take advantage of the specific ac- V tion of the different metals.

In carrying my-process into practise I use an apparatus of the general type of gas ing units in the manner ever, that it or retort is heated externally and supplied scrubbing tower constructed of iron or other heat resisting materials and provided with trapped outlets and trapped inlet. The retort or scrubbing tower is filled with packheretofore described. The retort or scrubbing tower is heated on the outside toabout 600 C. by burning fuel in a furnace built around same. In other words, the apparatus is run similarly to a gas scrubbing tower with the exception howdifi'ers only in that the tower let instead of an a 'by the process may be carried intoefiect.

the, figure shows a-- vermower-c1; retort conand prohere In said drawing, tical cross section of taining the catalytic packing units, vided with gas and other connections, inafter described. 1

The tower 1, filling of packing units 2, is

heated, in part by. the'lieat containedin the previously prepared molten cyanid mixture 3, and is kept molten in the funnel charging hopper 4, by the external heat supplied by the furnace A. The molten cyamd flows over theedg'e of the trap pot 5, and trickles downwardly through the packing units countercurrent to a flow 0 hydrocarbon vapor supplied through the pipe 6, from an adjoining still or. the oil may be sprayed directlyinto the scrubbing tower at or near the bottom as at 6. The lower end of the scrubbing tower or retort is closed to the atmosphere and is provided with the sealed outlets 7 and 8 for the molten reaction product and unvaporized oil respectively. At the upper end of the scrubbing towelor retortis an outlet 11 for the hydrocarbon vapors and gases which have undergone treatment in contact with the molten cyanid material and packin units. Molten cyanicl and the hydrocar on oil or vapor to be treated are continuously supplied as at 3 and 6 to the scrubbing tower or retort at the top and bottom respectively and converted hydrocarbons and molten reaction products are withdrawn from the scrubbing tower as at 11, 9 and 10 at the top and bottom respectively, the temperature of the scrubbing tower or retort being maintained and con trolled by the heat supplied by the furnace B.

In practise I aim at making the process continuous. Under proper regulation and conditions which are readily controllable the process operates continuously with excellent yields of low boiling saturated hydrocai'bons. The gases emanating from the scrubbing tower orv retort may pass into a dephlegmator or fractionating column, which may be suitabl arranged to yield as fractions 2. gas 0'; and unconverted kerosene, if the latterzi'sg employed as the raw material. Either or both of these products may be returned to the reaction zone for further decomposition if desired.

The li hter oils or volatile spirits are condensed in either a dephlegmator or condenser or the wellknown absorption, process may be used and the gasolene distilledirom the absorption oil used; The condensed, product requires. no

further treatment, as G III for example, refining by means of sulphuric acid and alkali or like treatment. The uncondensable gases after removal of the liquefiable hydrocarbons may be used as fuel for heating purposes and also asthe hydrogen containing gases used to admix with the hydrocarbons tobe treated. The function of these gases as aforesaid is to effect hydrogenation by the action oftheir free hydrogen content when exposed to the catalytic surfaces under conditions prevailing in the herein described process.

The use of the cyanid material in the molten state, very substantially reduces the amount of fuel required for the external heating of the reaction chamber and consequently reduces the cost of operation while at the same time permitting thorough and uniform and readily controlled heating of the catalytic filling wherein the pyrogenetic decomposition of the hydrocarbon material is effected, this together with the desulphurization and hydrogenation of the hydrocarbon products produced is a very important and advantageous feature of the process.

The points to be observed for the successful operation ofmy process are more or less obvious in View of the foregoing description. It will be apparent that many processes and many different forms of apparatus may be devised which .will fulfilltheconditionsrequired in theprocess.

I claim:

1. The process of making'gasolene like material from heavier hydrocarbon oil which comprises, cracking such heavier oil by commingling it with a molten body containing alkali metal cyanid in the presence of a -metallic catalyst maintained at cracking temperature.

2. The process of making gasolene like material from heavier hydrocarbon oil which comprises, cracking said heavier oil by commingling it with a molten body containing sodium cyanid in' the presence of a metallic catalyst maintained at cracking temperature.

3. The process of-making gasolene'like material from heavier hydrocarbon oil which comprises, cracking and desulfurizing such solid catalyst 4. The step in theherein described process of converting higher boiling oils into lower boiling oils which comprises, contactlng such higher boiling OllS with a molten body'containing sodium cyanid in the presence of a metallic catalyst maintained at a cracking temperature, and collecting the evolved hydrocarbon vapors and gases.

- 5. The process of producing gasolene like material from heavier hydrocarbon oil which comprises, catalytically cracking such heavier oil by commingling the same with a molten body containing sodium cyanid and sodium thiocyanate in the presence of a metallic catalyst maintained at a cracking temperature.

6. The step in the herein described process of making a gasolene substitute which comprises contacting molten sodium cyanid with hydrocarbon material heavier than gasolene in the presence of a metallic catalyst maintained at cracking temperature.

7 The process of producing gasolene like material from heavier oil which-comprises flowing said oil in the presence ofhydrogen into contact with a molten body containing sodium cyanid through a retort filling of nickel packing units maintained at cracking temperature, supplying the said molten body to and withdrawing the reaction products comprising molten material and unvaporized oil fromthe retort filling of packing units through liquid sealed passages, and collecting the evol retort.

8. The process of making a gasolene sub stitute the step comprising, contacting molten sodium cyanid with a hydrocarbon heavier than temperature.

Signed at New York city in the county of New York and Stateof New York, this 1st day of September, A. D. 1922.

JOHN COLLINS CLANCY.

gasolene in the presence of a' comprlsing nlckel at cracking ved vapors and gases from the

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