US2409587A

US2409587A - Combination hydrocarbon dehydrogenation and hydrogenation process

Info

Publication number: US2409587A
Application number: US551265A
Authority: US
Inventors: Alexander S Ramage
Original assignee: ALBERT A F MAXWELL
Current assignee: ALBERT A F MAXWELL
Priority date: 1944-08-25
Filing date: 1944-08-25
Publication date: 1946-10-15
Anticipated expiration: 1963-10-15

Description

` A. s. RAMAGE Oct..V l

COMBINATION HYDROCARBON DEHYDROGENATION AND HYDROGENATION PROCESS Filed Aug. 25, 1944 FFSS En 0:0

Y( NEW 4.25.0 NLR- INVEOR. A/exa/zaer 5. @maja i BY I Patented Oct. 15, 1946 COMBINATION HYDROCARBON DEI-IYDRO- GENATION AND HYDROGENATION PROC- ESS Alexander S. Ramage, Detroit, Mich., assignor to Albert A. F. Maxwell, Detroit, Mich., as trustee Application August 25, Serial No. 551,265

9 Claims. 1

The present invention relates to a novel process for the treatment of hydrocarbons, such, for example, as hydrocarbons contained in crude oils, low temperature tar oils, shale oils, and the like, for the purpose of producing a gas rich in ethylene and containing only small amounts of propylene and butylene, and a high yield of a liquid mixture consisting chiefly of liquid aromatics and the condensation products of the aromatics and gaseous olens of high octane number.

The present application is a continuation-inpart of my copending application Serial No. 475,468, entitled Treatment of hydrocarbon oils, filed February 11, 1943.

In my prior Patent No. 1,752,692, issued April 1, 1930, and entitled Process for the production of gas and aromatic hydrocarbons from heavy hydrocarbon oils, I have disclosed a process and apparatus in which the hydrocarbons were dehydrogenated in the lower tubes of the converter by contact with ferrie oxide as the reactive agent. The dehydrogenated gases and vapors with a large volume of steam were subsequently passed through the upper tubes in the converter which were filled with metallic iron.

While the results of this process were quite satisfactory as a gas process, the liquid condensate tested 70 to 75 octane only.

This invention contemplates a process which Will give considerably higher yields of ethylene as Well as liquid condensate having a much higher octane number.

The hydrocarbons which are to be transformed comprise mainly paraflins (CnI-Izn+2) and olens (CHI-Ian). These hydrocarbons are rst dehydrogenated in the presence of heat to form aromatic hydrocarbons and unsaturated aliphatic hydrocarbons. During dehydrogenation the olefns also broke down into hydrocarbons having a lesser number of carbon atoms. After being subjected to the dehydrogenating step, the hydrocarbons are next subjected to a hydrogenating step in the presence of heat in which the unsaturated aliphatic liquid hydrocarbons are hydrogenated to form oleflns and parans having a lower number of carbon atoms than the paraiins and olens which constituted the starting hydrocarbons which were to be treated.

The single gure is a drawing diagrammatically illustrating the apparatus used for treating hydrocarbons according to my method.

My process can be carried on in the apparatus shown either in my Patent 1,752,692 or inthe apparatus disclosed in my copending application Serial No. 475,468 or in many known cracking convertors.

In the first step of my process I dehydrogenate the hydrocarbons by bringing the hydrocarbon to .be transformedu in a state of vapor substantially unmixed with reactive oxygen into contact with a mixture of reducible metal oxides comprising preferably substantially equal parts of molybdenum oxide (M003), chromic oxide (Cr2O3) and ferric oxide (FezOa) which has been activated by approximately ten percent (10%) of vanadium pentoxide (V205). The vanadium pentoxide can be used in amounts falling within a range of from about 2% to about 10% by weight of the total weight of the three oxides; namely, chromic oxide, molybdenum trioxide and ferrie oxide. Although the chromium, molybdenum and ferrie oxides each preferably comprise approximately 331/3% by weight of the mixture, their respective proportions by weight can be varied over a wide range provided the amount of oxygen necessary for dehydrogenation is liberated by the mixture. A variation of as much as 10% more or 10% less than the above proportion of any of the three oxides With a commensurate decrease or increase in the proportions of the other oxide or oxides of the mixture would work but for best results the use of the three oxides in approximately equal amounts by weight is indicated. A mixture of any two of the chromic, ferrie and molybdenum oxides can be used if activated with vanadium pentoxide but at a loss in the efiiciency of my process.

The hydrocarbons to be transformed, if not already in the gaseous or vapor phase, are preferably vaporized by heating in a pipe still l or other suitable heating equipment, or if in the liquid phase may be injected directly through an injector nozzle into the lower tubes 2 of converter 3 in which the dehydrogenation takes place.

The temperature of the reactive oxide mixture will depend on the hydrocarbon to be transformed. Preferably the reactive oxide mixture will be maintained at a temperature falling within a range of from about 800 F. to about 1100 F. The oxide mixture provides a reactive material which gives up oxygen to the hydrocarbon gases and vapors passing through the tubes or contacted therewith and in doing so at the temperature mentioned effects dehydrogenation thereof.

The length of time during which the reactive agent is active in the liberation of oxygen depende upon the analysis of the hydrocarbon being treated. By calculating the amount of oxygen present in the reactive agent and analyzing the hydrocarbon vapors being treated, a calculation can be made as to the period of time that the process may be operated before revivifying the said reactive agent. The time is gauged on the analysis of the material to be treated, as shown for example in the following chart:

4 heated mixture of reactive materials comprising essentially inely divided metallic iron activated with finely divided metallic copper. Preferably the mixture comprises approximately 90% of finely divided iron and of finely divided copper, but the mixture by weight can be varied from 90 to 98% of finely divided iron and 2 to 10% of finely divided copper. This mixture of finely Pounds oxy- Pounds per Pounds Formula Atqmic ga1. at Cubic ft. B. t. u's Jltlg oxygen grfglgd weight atmospheric per gal. per gal. degrees'F required convert; to pressure per pound aromatic Average 6. 416 1l. 66 130. 557 515 07682 492 i In all of the starting materials commonly employed in carrying out a process of this type, it will be found that there is a mixture of the hydrocarbons present and when such is the case,V

the average iigures included in the above chart may be taken for the purpose of making such calculations. For example, if 1500 pounds of the reactive material is employed in the dehydrogenation tubes, it will be found that approximately one hundred and fifty pounds of oxygen will be liberated. After this amount of oxygen has been liberated, the reactive agent is revivied by blowing with superheated steam for approximately five minutes and then blowing with air at fifteen pounds pressure for approximately twenty-five minutes. By reference to the above chart showing the number of pounds of oxygen required per pound and per gallon of the hydrocarbon materials, it is possible to calcul-ate the time period that the plant may be run Without revivifying the reactive agent.

The aliphatic hydrocarbons in the presence of chromic, ferric and molybdenum oxides activated with vanadium pentoxide Vat the temperature specified are dehydrogenated to form aromatic hydrocarbons and unsaturated aliphatic hydrocarbons. About 80% of the hydrocarbon vapor after dehydrogenation will be aromatic hydrocarbons (CnHzn-s) and the remaining hydrocarbon Vapors will be unsaturated aliphatic compounds. These unsaturated vapors will be, in the main, olefins. During the dehydrogenation step the olefins break down into hydrocarbons having a lesser number of carbon atoms. For example, C1zHz4 splits up at the temperatures specified into 2C6H12 which splits up into LiCal-1e, or starting with a paraffin, CisHai is oxidized or dehydrogenated to form CisHsz which at the dehydrogenating temperatures splits up into 2C8His and then into 4C4Hs and finally ethylene, 8C2I-Li.

In the hydrogenation step of the approximately 20% of the vapors the entire mass of hydrocarbons to be treated, subsequent to the dehydrogenation step, are passed in the form of vapors together with superheated steam through the upper tubes 4 of convertor 3 in 0011122.01? With a divided iron and copper is positioned in a second group of tubes in which hydrogenation takes place. The temperature of these tubes and the nely divided iron and copper mixture should be maintained Within a range of from about 1000 F. to about 1400 F. according to the nature of the hydrocarbons. During the hydrogenation the temperature within the above range will vary inversely to the number of carbon atoms present in the molecule of the material being hydrogenated. For example, a material consisting largely of G51-Ilo will use a temperature of about 14.00 F. whereas a material consisting largely o'f Cial-Iss will require a lower temperature of about 1200" F. Water in the form of superheated steam is blown into the tubes during hydrogenation and reacts with the iron and copper to liberate atomic hydrogen.

During the hydrogenating step the unsaturated aliphatic liquids present in the form of vapors are' hydrogenated to form olens and parafflns but having a lesser number of carbon atoms in a molecule than theparanins and olens which formed the starting materials. The vapors from the hydrcgenating tubes may be condensed in the usual manner and treated according to normal refinery practice. The gases remaining after condensation may be treated in conventional types of liquefaction apparatus to effect separation of the ethylene from the other gases. The liquid condensate is a mixture of aromatic hydrocarbons and light saturated hydrocarbons and when tested according to the A. S. T. M.C. F. R. Motor Method it has been found to have an octane numiber of from to 106 with an end point of 310 F, and a specic gravity of 30 to 35 Baum. The yield of liquid product may be varied by varying the temperature, the rate of flow, and the type of starting material. A liquid material having a specific gravity of approximately 30 Baum and an octane number in excess of 100 may :be produced in the amount of approximately ten gallons to the barrel of oil, kerosene or low grade gasoline used as a starting material and also about 2800 cubic feet of gas containing 40 to 45% 02H4 equal to '78 to 88 pounds C21-I4 per barrel will be produced. A liquid product having aspecic gravity of approximately 34 Baum and having an octane number of from approximately 90 to 92 may be produced in anamount of approximately fteen gallons to the barrel of starting material and also 2200 cubic feet of gas equal to 65 to 75 pounds CzHr per barrel will be produced. Producing 8 gallons per barrel of spirit of 100 plus octane, there would be produced also 2820 cubic feet of gas containing 85 to 95 pounds 02H4 per barrel.

From the converter 3 the vaporsl are quenched, passed through av Gray tower, then through a fractionating tower (the heavy liquid being returned for recycling) and finally passed through a condenser where thearomatic hydrocarbons have a specic gravity of 30-35 Baume and consisting chiey of benzoyl, toluene and xylol are condensed out and the uncondensed gas is then passed on for further treatment.

It has been found that as the volume of liquid distillate produced is increased, the octane value and the amount of gas is decreased. The process is, therefore quite exible as to the relative amounts of liquid condensate and gases to be produced. 'Ihe composition of the gases varies according to the temperature employed but in the usual instance using temperatures within the ranges above described, it has been found that the gas consists of approximately 40 to 45 percent of ethylene with very low percentages of propylene and butylene, in the usual case not over approximately 4 to 5 percent. The balance of the produced gas is methane.

For each barrel of starting material put through the process, approximately 2600 cubic feet of gas containing approximately 86 pounds of ethylene may be produced when approximately ten gallons to the barrel of the liquid distillate is recovered having the characteristics above described. If the liquid distillate is recovered to the extent of fifteen gallons to the barrel and has the characteristics above described, the gas yield will be reduced to approximately 2200 cubic feet of gas containing approximately seventy-four pounds of ethylene.

I claim:

1. The process of transforming hydrocarbons into other hydrocarbons relatively poorer in hydrogen, which consists in bringing the hydrocarbon to be transformed in a state of vapor substantially unmixed with reactive oxygen, into contact with a mixture of molybdenum oxide, chromium oxide, and ferric oxide and vanadium pentoxide, and so regulating the temperature of the oxide mixture and vapor between about 800 F. and about 1100 F. so as to oxidize a part only of the hydrogen component of the hydrocarbon producing thereby as reaction products hydrocarbons comprising principally aromatics and lesser quantities of other unsaturated hydrocarbons relatively poorer in hydrogen, and steam.

2. The process as set forth in claim 1 wherein the time of contact of the vapor and oxide mixture is regulated so that the hydrocarbons relatively poor in hydrogen split up into lower boiling hydrocarbons of the same chemical group and thereafter contacting the vapor with a mixture of finely divided metallic iron and finely divided metallic copper in the presence of steam to hydrogenate the unsaturated hydrocarbons produced during the dehydrogenating step.

3. The process of transforming hydrocarbons into other hydrocarbons relatively poorer in hydrogen, which consists in bringing the hydrocarbon'in a state of vapor into contact with a mixture of molybdenum oxide, chromic oxide, ferric oxide activated with vanadium pentoxide, and regulating the temperature of the oxides and vapor between about 800 F. and about 11001F. and the ,time of contact of the vapor withthe oxides so as to partially dehydrogenate the hydrocarbon producing thereby as reaction products principally aromatic hydrocarbons and a small -amount `of oleiins having a relatively smaller number of carbon atoms per molecule lthan the olens produced directly from the hydrocarbon, then hydrogenating some of thek olens toproduce lower boiling hydrocarbons .than those orig inally dehydrogenated.

4. The process as set forth in claim 3 wherein the said oxide mixture comprises substantially by weight one-third molybdenum-oxide, one-third chromic oxide, 'and one-third ferric oxide, and the activating oxide, vanadium, pentoxide, comprises Iabout ten percent by weight of .the mixture of the other three oxides.

`5. The process of transforming hydrocarbons into other hydrocarbons relatively poorer in hydrogen, principally aromatics which consists in bringing the hydrocarbon in a state of vapor into contact with a mixture of molybdenum oxide, chromic oxide, ferrie oxide activated with vanadium pentoxide, and regulating the temperature of the oxides and vapor between about 800 F. and about 1100" F. and the time of contact of the vapor with the oxides so as Ito partially dehydogenate the hydrocarbon producing thereby as reaction products principally aromatic hydrocarbons and a small amount of olens having a relatively smaller number of carbon atoms per molecule than the olens produced directly trom .the hydrocarbon, and then hydrogenating the `olenic part of the vapors by contacting the same with nely divided metallic iron activated by finely divided metallic copper in the presence of water in the form of superheated steam.

6. The combination as set forth in claim 5 wherein the steam and nely divided copper and iron are maintained at a temperature falling within a range of about 1000 F. to about 1400 F. during the hydrogenating step.

7. A process of transforming hydrocarbons selected from the group consisting of parains, olens, and mixtures of paraflins and olens, into hydrocarbons comprising principally aromatics and lesser quantities of other hydrocarbons having a lesser number of carbon atoms in the molecule Ithan the hydrocarbons to be transformed,

comprising bringing the hydrocarbon to be transformed in a state of vapor into contact with a mixture of at least Itwo metal oxides selected from the group consisting of chromic oxide, molybdenum oxide and ferric oxide, activating said mix- .ture of oxides with vanadium pentoxide and maintaining .the temperature of the oxide mixture and vapor within a range of from about 800 F. to about 1100 F. so as Ito oxidize a part only of the hydrogen component of the hydrocarbon to be transformed producing thereby as reaction products principally aromatics and lesser quantities of unsaturated aliphatics having a lesser number of carbon atoms in the molecule than the hydrocarbon to be transformed, and then bringing the unsaturated aliphatics in a state of vapor into contact with a mixture of nely divided metallic iron and finely divided metallic copper in .the presence of superheated steam while maintaining said copper and iron 7 mixture and vapors at a temperature within 'a range of about 1000 F. to about 1400 F. to thereby hydrogenate the unsaturated aliphatics.

8. A process of Itransforming hydrocarbons se# lected from the group consisting of parafns, olens, and mixtures .of parains and olens, into hydrocarbons comprising principally aromatics and lesser quantities of other hydrocarbons having a lesser number of carbon atoms in the molecule than the hydrocarbons to be transformed, comprising bringing the hydrocarbon .to be transformed in a state of vapor into contact with a mixture of at least two metal oxides selected from the group consisting of chromic oxide, molybdenum oxide and ferrie oxide, activating said mixturc of oxides with vanadium pentoxide and so regulating the temperature of the oxide mixture and vapor between about 800 F. and about 1100" F. so as to oxidize a part only of .the hydrogen component of the hydrocarbon Ito be transformed producing thereby as reaction. products principally aromatics and lesser quantities of unsaturated alphatics, and steam, regulating the temperature and time of contact of the hydrocar-J bon vapor and activated oxide mixture so that .the olens present during the dehydrogenating step split up into olens with a lesser number of carbon atoms and hydogenating the oleiins to form paraflns having a lower boiling point than the parailins to be transformed.

9. In Ithe hydrogenating of unsaturated aliphatics, the step of bringing the unsaturated aliphatic in a state of vapor into contact with a mixture of nely divided metallic iron and nely divided metallic copper in the presence of superheated steam, the content of iron of said mixture falling within a range ofV from about 90 to 95% by weight and the content of copper in said mixture falling within a range of vfrom about 2 to about 10%V by Weight, and maintaining theY temperature of the iron-copper mixture and vapor within a range of from about 1000 F. to about 1400 F. whereby said unsaturated -aliphatics are hydrogenated.

ALEXANDER S. RAMAGE.