US1833155A - Process of increasing the yield of light hydrocarbons from oil shales - Google Patents

Description

Nov. 24, 1931. 1,833,155 PROCESS OF INCREASING THE-YIEILD OF LIGHT HYDROCARBONS FROM OIL SHALES sf DANNER ET AL Filed Sept. 28, 1925 nm (06 L OHIIN Iain/40E Patented Nov. 24, 1931 UNITED STATES PATENT OFFICE PHILIP s. BANNER, or rorNr RICHMOND, AND ERNEST E. LYDER, or BERKELEY; CALI- FORNIA, ASSIGNORfi, BY MESNE ASSIGNMENTS, TO STANDABD OIL .COMPANY OF.

' CALIFORNIA, OF SAN FRANCISCO, CALIFORNIA, A CORPORATION OF DELAWARE rzaoenss or INCREASING rHE-YrnLn or LIGHT HYDROCARBONS FROM. on. SHALES Application filed September This invention relates to processes of treating oil shales to obtain various products therefrom, and an object of the invntion is to secure a more complete recovery of the carbon, present in the shale, as light hydrocarbons of a superior quality.

0 nite temperature.

- slowly inward from the surface of the shale particles. At temperatures slightly above this temperature of transformation the soluble, bitumen begins to distil from the mineral matter, which constitutes the body of the shale, and at the same time to crack to lighter hydrocarbon products.

'v A large amount-of carbon is deposited in the ash during the cracking of the soluble bitumen and the crude shale hydrocarbons have a low degree of saturation. Hydrogen containing gas, if introduced at atmospheric pressure, diffuses but slowly through the layer of ash left on the surface of'the par ticles of shale as the cracked products are vaporized and carried away, and consequentlyit is always relatively far removed from the z'oneof reaction as said zone proceeds toward the center of the shale particles. Accordingly, it will be seen that there can be little, if any, benefit derived from the presence, of the hydrogen-containing gas introduced at atmospheric pressure to the retort excepting, possibly, for a slight buffer action in protecting the hydrocarbonmolecules from the superheated walls of the retort. r

We have discovered that, by circulating hydrogen-containing gas under high pressure and temperature through the retort,

such hydrogen gas serves to convey the requisite amount of heat to the zone where the reactions should be completed in order to utilize the carbon'content of the shale,

and the hydrogen-containing gas also serves to remove the prodgcts of the reaction.

When hydrogen-containing gas,'1inder relatively highpre'ssure and temperature is in- 28, 1925. Serial No. 59,106.

troduced to the retort, the highly compressed gas diffuses readily through the porous ash to'the region of reaction and because ofsuch' gases possessinga relatively'great capacity for'heat, the temperature of the shale mass. is raised without difficulty to a degree sutficiently high for rearrangement of the molecules and also the temperature may be raised sufliciently for. cracking with sufli cient uniformity and rapidity so that the several reactions may proceed as a substantially single rearrangement instead of in gen is not circulated under high pressure. The presence of highly reactive hydrogen because of, the porosity of the shale at the immediate point at which these extensive molecular rearrangements are taking place permits of the nearly complete saturation of the chemicalatfinity of the carbon atoms, and thus prevents the separation of free carbon atoms and insures a high degree of saturation of the products" formed. This may result in increasing the yield of light hydrocarbon materials by as much as from fifty to one hundred per cent. I

The hydrogen-containing gas may be'employed under pressures of about 50 up to 250 atmospheres and undertemperatures of about 400 C. to 500 C. Inthe-present proc-' 'ess the shale may be employed as mined and cjrus'hedto from one to two inch mesh. The oil shale subjected to the operations of this process may have associated with it, coal or a material occupying the region between shales and lignit'es, but such coal'or other associated material does not have the porosity that is an important factor in, this.

process. and, therefore, theshale shouldbe in predominating volume;

It is well known th t many reactions, in; vol-ring one ormore gases, are very materia lly hastened by the presence of certain: highly poronis materials such as the many forms of actiire charcoal and silica-gel. An exactly analogo s action is obtained in this separate steps as results when the hydroprocess by the presence of thehighly porous V shale ash which markedly increases the activity of the hydrogen. The beneficial effect,

obviously, will vary somewhat with theloo respectively, and removable covers 12 are pro I chemical nature of theash from different shales but to a far greater degree the effect will vary with the physical structure of thei ash and, accordingly, the pressure of the hydrogen used in the process for securing a given amount of hydrogenation may vary between wide limits. The partial pressures of hydrogen employed may vary from about 800 lbs., per square-inch-to well above 2000 lbs, per square inch. Pressures of about 1000 lbs., are preferred.

The'yield of ammonia is highly sensitive to the amount of water vapor present in the gases of the retort. For this reason it will be usually desirable to circulate a small per cent of steam along with the hydrogen in the retort. The addition of steam may not be necessary during the early stages of the retorting as sufficient moisture will usually be found in the shale to generate the necessary steam, but after this moisture has disappeared the supply will need to be augmented from withou v I As the reaction progresses hydrogen is used up and light hydrocarbons are produced, thus making it necessary to eventually remove the fixed hydrocarbon vapors and replenish the supply of hydrogen. These ends may be accomplished by the catalytic decomposition of the light hydrocarbons, such, for example, as propane, butane, methane and the like, without their removal from the circulating gases, thus materially reducing the amount of hydrogen that must be supplied. It isto be understood that pure hydrogen gas is not required, and any gas containing hydrogen in sulficient quantities to be effectively used, such as gas from the-catalytic decomposition of light hydrocarbon mentioned above, may be employed. Pure hydrogen 'gas is, of course, preferredbu-t its use may not be economically possible under some conditions.

The process may be performed in any suitable apparatus and one such apparatus is v illustrated in the accompanying drawing which is a more 'or less diagrammatic view thereof. r y

The apparatus illustrated is constructed as follows:

There is provided. a heater o j furnace 1' and inside thereof is a hydrogen-containing gas heating coil 2. The furnace may be heated by any suitable means, as by gas flowing frdm a gas holder 3 through a pipe 4 to a burner 5' positioned in the combustion chamber of the furnace.

The lower end of the coil 2 is connected by a branched pipe 6,provided with valves 7,

71, with the 'l puwer portions of retorts 8,9.

- iiicient for carrying out the process, but whena. plurality is employed the process is semi-continuous. The retorts 8,9 are fed with shale from hoppers-10, 11,

vided to close the upper ends of the retorts during the retofting operation. Also the lower'ends of the ret-orts 8, 9 are likewlse closed by removable covers 13. Below the 4 retorts 8,9 are ash conveyin means 14 which,

in this instalfce, are in the orm of cars run-- desired place of discharge. Leading into the trap 24 is a pipe 27 having a valve 28 and leading from the lower portion of a trap 29. Leading from the upper portion of the trap 29 is a by-pass pipe. 30 having a valve 31 and connected with the pipe 20 between the pump 21 and purifier 19.

Leading into the upper portion of the trap I 29 is a condensate pipe 32 connecting with a water cooled condenser 33, and leading to said condenser is a vapor pipe 34 that is connected with the upper end of a trap 35. Leading from the lower portionof the trap 35 is a condensate pipe 36 which is branched'and which connects with the upper portions ofthe retorts 8, 9. The pipe 36 is provided with a'valve 37 and with valves 38, 39 on its branches.

Leading into the trap 35' is a condensate pipe 40 that connects with an air cooled condenser 41 which in turn is connected by a branched vapor pipe 42 with the'u'pper portions of the retorts 8, 9, the branches of said pipe being rovided with valves 43, 44. The

branches 0 the pipe 42 are-connected by a branched pipe 45 with a pump 46,'and the branches of the pipe 45 are rovided with valves 47, 48, respectively. onnecting the pipe 45 with agasholder 49. is a pipe 50'proipe 42. The branches, of r i I vided with valves 53, 54, 55, respectively. 1 r

The branch of the pipe 52 on which is positioned the valve 55 connects with the lower end of the gas holder 3. Connected with the branches of the pipe 6 arepipe 56, 57 provided, respectively, with valves 58, 59. I

The process is performed in the apparatus above described as follows; I The shale is charged from one of the'hoppers 10, 11 into the associated retort. For example, it may be assumed at the beginning that the shale is discharged from the hopper 10 into the retort 8.- Before charging, the cover 12 is removed and after the charging is completed thecover 12 will be secured in place. Hydrogen-containing gas from a suitable source, for example from the gas holder 49, will then be pumped into the retort 8 by operation of the pump 46, all valves being closed excepting 51, 53, 43, 31, 71 and 28. When the system, including the retort I 8, the condensers 33, 41,.the traps 24, 29, 35, the purifier ,19, the pump 17 and the heating coil 2 ispumped to the proper pressure by operationof the pump 46, the valves 51 and 53 will be closed and the pump 46 stopped. The pressure is. comparatively.

high, for example, around 250 atmospheres.

Then the circulating pump 17 is started into operation and the furnace is heated sov as to heat the coil 2. The hydrogen contain ing gases will be heated in the coil 2 and will pass therefrom into the retort 8 andw through the mass of shale in said retort. thence-into the condensers 41-, 33. 'Because of the porosity of the shale, the hydrogen gas thoroughly and quickly penetrates the shale, and this results in the hydrogen being present at the immediate point at which the molecular rearrangements are taking place, permitting of the nearly complete saturation of the carbon atoms, thus preventing the production of free carbon atoms and insuring a high degree of saturation of the desired products. ,The increase in the yield of light hydrocarbon materials within the gasoline range may amount to from 50 to 100%. The

. reaction of the hydrogen gas with the hydrocarbon is materially hastened by reason of the reaction occurring in the presence of the highly porous shale, similar to the increased chemical reaction that occurs in the presence of active charcoal and silica-gel.

As the circulation of the hydrogen-containing gas continues, the, pyrobitumen in the shale is decomposed and the bitumen hydrogenated, cracked and distilled in the retort. The heavy vapor products, carried out of the retort with the gases through the pipe 42, are condensed in the condenser 41. i The heavy liquid products are caught in the trap'35 and the gases and lighter vapors pass on to the condenser 33. These heavy liquid productsmay be returned, if desired. to the 7 retort 8 for further cracking by opening the valves 37, 38. i 7

The lighter vapors are removed in the condenser 33 and caught in the trap 29 and theymay be drained, from time to time, into the trap 24 in which the pressure is relieved and from which the liquid products are drawn oi f by opening the valve .26. v

The gases which remain when the pressure is relieved in the trap 24, are pumped back into the system by operating the pump 21 I which forces the gases through the purifier 19. The purifier 19 may be charged with such reagents as will remove detrimental impurities. From the purifier the gases are again circulated by operation of the pump 17, and

of hydrogen-containing gas, the valves 51 and 53 will be opened and the pump 46 operated.

The circulation of the hot hydrogen-cbhtaining gases is maintained until such time as it is found that substantially all of the pyrobitumen in the shale has been converted into the desired products.

In order to remove thegases from the re-- tort 8 and carry them to the retort 9, the pump 46' is operated and the valves 47 and 54 will be opened and the valves 43, 53, 71 and 38 will be closed. For still more completely 'r'emoving the gases from the retort 8 it may be necessary to open the valve 58 and 1111801, steam into said retort. When all the gases are exhausted from the retort 8, the valves 47, 54

Will be closed, valves 44 and 7 opened, and the treating of the shale in'the retort 9 will be effected the same aspreviously described for 4 the shale in the retort 8. While the shale in the retort 9 is being treated, the covers 12, 13 of the retort 8 will be removed and the residue dumped from the retort 8 into theassociated car 14. V

The form of construction of the furnace 1 will depend on the disposition it is desired to make of the fixed gases produced during the reaction in the retorts, or, in other words,

whether or not it is desired to burn the excess fixed gases in the furnace. Such gases will accumulate and, if not removed produce undesirable dilution of the hydrogen. 'The introduction of the necessary catalyst and the operation of an apparatus for cracking these gases to produce hydrogen and carbon black or to effect polymerization to liquid hydrocarbons need not affect the operation of the process above described.

Under-certain conditions it may be found necessary to remove a part or all of the fixed ,gases from the system ratherthan to pump them to another retort. This can be done by opening the valve 55 and operating the pump 46 to force the gases to the gas holder 3.

These gases can then be conveyed to the furj nace through the pipe 4 and burned, if that be desired. 1

It will be readily understood that in the process the materials to be treated are placed in a circuit of hydrogen-containing gas under pressure, and that the gas is heated while circulating.

We claim: 1. The process of increasing the'yield of light hydrocarbons from oil shales which consists in charging the oil shale into an enclosed space, compressing a hydrogen-containing gas to a pressure of about 250 atmospheres, heating thecompressed gas to a temperature of about 500 degrees C., circulating the hot compressed hydrogen-containinggas through the enplosed-space to decompose and hydrogenate and crack and distil the pyrobi tumen in the shale and to carry ofi the reshltingheavy and light vapor products and the time of their formation from kerogen in J such pyrobituminous oil shale, permitting the current of gas to carry the resulting heavy and light hydrocarbon vapors out of said reaction zone, condensing and separating heavy hydrocarbons from said current of gas, and

0 condensing and separating the light hydro: carbon vapors from the un ndensible gases.

3. The process of increas ngthe yield of light hydrocarbons from pyrobituminous oil shales, which comprises forming a bed of a p-yrobituminous oil shale in a pressure rerobitur'ninous oil' shale, removing the resulting mixture of light and heavy hydrocarbon vapors and hydrogen and fixed gases from said pressure reaction zone, condensing and separating heavy hydrocarbon vapors from said mixture of vapors and gases, condensing and withdrawing light hydrdarbons, from the uncondensed hydrogen-containing gas,

and reusing uncondensed hydrogen-contain- 7 in gases in cyclic operation of the process. igned at Richmond, California this 12th day of September 1925.

PHILIP S. DANNER. ERNEST E. LYDER.

action. zone, compressing hydrogen gas to a pressureabove 800 lbs., per square lnch, heat: ing the compressed gas to above 400 (1., passing the hot compressed gas through the reaction zone to remove moisture from said pyrohot compressed gas therethrough so as to hydrogenate hydrocarbons at the time of their formation from said pyrobituminous oil shale, removing the resulting mixture of light j and heavy hydrocarbon vapors and hydrogen and fixed gases from said pressure zone,

condensing and separating heavy hydrocarbon'vapors from said mixture of vapors and gases, and finally condensing and separating light hydrocarbons from the uncondensed hydrogen-containing gas.

4. The process of increasing the yield of light hydrocarbons from pyrobituminous oil shales which comprises forming a bed of pyrobituminous oil shale in a pressure reaction zone, compressing hydrogen gas to a ressure above 800 pounds per square inch, eatin g the compressed gas to above 400 0., and passing the hot compressed hydrogen gas through the reaction zone to remove moisf turefrom said pyrobituminous oil shale, 'con tinuing to .pass the hot compressed gas therethrough so as to hydrogenate hydrocarbons -at the time of their formation from said pybituminous oil shale, continuing to pass the

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