US1742165A - Method for obtaining hydrocarbons of low boiling points from hydrocarbons of high boiling points - Google Patents

Description

1,742,165 NG POINTS P. DANCKWARDT 13 LOW BOILI FROM HYDROCARBONS OF HIGH BOILING POINTS Filed April 25, 1927 METHOD FOR OBTAINING HYDROCARBONS O Dec. 31, 1929.

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This invention relates to a process, for producing from fixed hydrocarbon gases and such hydrocarbons of high boiling points, as for instance fuel oil or tar, hydrocarbons p of low boiling points, identical with or simi lar'to gasoline. lit is known as a fact that hydrogen can be added to or combined with certain hydrocarbons by the application of high pressure and high temperature, but as n this is usually carried out by an apparatus in which firecomes into direct contact with the oil container, a great deal of carbon is formed by the intense heat and this, in conjunction with the high pressure required, has s prevented this process from becoming of commercial value to the oil industry. T have, therefore, discarded direct heat by combustion altogether andattain the desired conditions in an altogether novel nd perfectly as practical way. I r

The invention, briefly described, consists in producing the required temperature and pres sure in a mechanical way by compressing the fixed as andaipart of the oil vapor to a high egree, this compression totalre' place within the body of oil, and separating the light'hydrocarbons formed from the oil by fractional distillation. Though there is always under these conditions a certain amount of free hydrogen formed besides light hydrocarbons, escaping from'the condensing apparatus, it is naturally desirable to have an excess of free hydrogen inorder to produce a more favorable chemical equilibrium be- 1 of the accompanying drawing represents a longitudinal section of the apparatus which I employ for carrying out the 50 process; and

tween the products entering into reaction with each other -in the stilL- Therefore, it is Figure 2 shows a detail of a modified con struction.

The still consists of a steel shell l-l-1--'--il of cylindrical cross-section which is well in sulated by an outside covering of asbestos 22-%2, which reduces the loss of heat by conduction to a minimum. At one end a manhole 3 is provided, and valved pipes 4t and 5 serve as inlet and outlet of oil. A pipe 6 connects the'still with an air-cooled con desner 7, fromwhich the uncondensed light hydrocarbons are transferred by means of the valvedpipe l to a water-cooled condenser 9, The products are then discharged into a-closed vessel 10, from which the fixed gases may be allowed to escape into the air through valve 31, or they may be conveyed through a pipe 11 and the short branch pipe 32 baclr into the system, or they may be made to pass first through a heater 28, containing red hotcarbon by closing valve 32 and opening valves 3d and 37," and then baclr to the still, as may be'required at the diderent phases of the operation of the process Two valves 33 and 3dare provided in pipe it for the purpose of controlling the flow of gases' lln the interior of the still l--l--l-l there are placed one or more compressors l3l3-l3 arranged above and resting on cross bars M ttit which are riveted to the shell of the still, These compressors may all be driven by the same crankshaft 15--l5, The journals ld--ltt-lli-lt supflit (lift fit) port the shaft inside of the still. flnthe outside there is another journal If, and near, it is placed the flywheel 18. The shaft is then coupled to the prime mover 19, which may be a gas, oil or steam engine. it stud ing box 20 is provided with a branch at,

through which cold oil may be introduced a to keep the intense heat away from the packing. llf more than one compressor is used, which is the best plan where high pressure is desired, the cylinders are roportionately reduced in diameter, and 'te compression products from the first one on the left pass serially to the central one, and from this to the right hand one through pipes E222 and 23, and are then forced intoa longclosed coil 24--% which is provided at its. enthe treme end with an automatic pressure valve that will open at a certain pressure of the gas slightly below that of the pressure when the gas leaves the last cylinder. This coil thus serves as a reservoir for the compression products and holds them unt1l they have surrendered their compression heat to the surrounding body of oil. Besides this it regulates the escape of the products into the oil without sudden shock. The intake 25 to the left. hand compressor has two branches 26 and 27. Both pass outside through the shell of the still and each branch isprovided with a valve located outside of the still. Pi e 26 is, however, bent back and its open end connects with the vapor space above the oil level inside of the still. The otherpipe 27 connects the compressor with the top of the producer 28. The compressor, therefore, can draw ases .from the producer or vapors fromthe interior of the still, or from both places-at the same time and in any desired proportion vaccording to the setting of the valves. v v

The producer is provided near its bottom with a valved air supply pipe 29 and a valved outlet pipe .30, these valves being opened only when air is passed through the interior for heating the carbon (coke contained in it, which must be done whenever the temperature of the coke falls too low for decomposing the fixedhydrocarbon gas.

At such times the valve of pipe 27 must be closed in order to allow the combustion es to escape only through. pipe 30.

and pipe 11. The 'light hydrocarbons formed-by the process are. collected in the receiving tank 10 and may be withdrawn from it through a valve 35.

I will now proceed describing the operation of the rocess in detail, as it may be carried out in the above apparatus.

We will suppose that the producer 28 is to be used to supply plenty of hydrogen in the free state, as it assists greatly in roducing the largest ossible amount of light hydrocarbons. Be ore igniting the fuel, however, itis necessary to expel all the air from the still, as otherwise, when hot bydrogen-is introduced, an explosion or at least a violent combustion might ensue. The

still is therefore first filled with oil, which may be preheated, up to a level just below the opening of pipe 26, and with the valves in dpiples 26, 27 and the valves 33, 34 shut an t e valves in pipes 812 and valves 31 and 32 0 en. I now; start the engine 19. Hydrocar 11 gas is-admitted through the pipe 12 from an outside source (not shown), the compressor suckin it through the cross line and valve 32 and discharging it into the oil through the valve in the end of pipe 24, from where it rises to the space above the ere is also a branch line with a valve 32' for forming a short cut between pipe 27 oil, driving all the air gradually out of the whole system through valve 31. I then close valve 31 and open 33 and continue the operation of the compressors, which now circulates the hydrocarbons contained throughout the whole apparatus, and the compression heat gradually raises the temperature of the oil to its boiling point, whereafter valve 26 maybe opened and so re ulated that the compressors take in, beside's fixed hydrocarbon gas, a certain amount of va or from the space above the boiling oil. lihder the influence of the high pressure and the high temperature within the compressor cylinders and the coil, the vapors of the heavy oil are cracked inside of the cylinders and coil. and recombine with a part of the hydrocarbon gases and hydrogen to form hydrocarbons of lower boiling points, which will escape as vapor into the condensers, the last one of which condenses the lightest part of them, the aircooled condenser separating out some heavier hydrocarbons which will flow back through pipe 6 into the still.

In the meanwhile the charge of the producer may have been ignited and it is oper+ ating as a producer generally is, the air being blown in at 29 and the combustion gases escaping from 30. When the charge of coke is hot enough, this process is interrupted by closing the valves in pipes-29 and 30. I

then open the valve 34 and the valve in pipe 37 and close the valve 32, whereby the current of fixed gas is changed so that it traverses the producer before entering the compressors. The valve in pipe 12 remains open so that always some fresh fixed hydrocarbon gas may be drawn in by the compressors whenever needed. The fixed hydrocarbons incoming now in contact with the red hot carbon in the producer are broken up forming mostly carbon and hydro en which latter in being compressed with t e vapors comin through 26 form with them the desirable ydrocarbons of low boiling points, and this more readily than the undecomposed fixed hydrocarbons do. Working in this way the heavy oil surrounding-the compressors and the coil is not submitted to extreme temperatures as in a firP--'.'-ated still, which would cause it to decum p use into carbon and fixed gas, but only such part as is drawn into the cylinders is highly heated, but very uniformly without beingexposed to red hot spots as happens' alwaysin a fire-heated still or coil, apd as it i's-in, contact with an excess of free'hydrogen under a high pressure it finds the conditions most favorable for the formation of saturated hydrocarbons of low-boiling points. By the proper manipulation of, the valve 26, the proportion of oil vapor and fixed gas can be easily adjusted so as to yield the best rether more vapor would be admitted to the ture of the oil surrounding the compressors andcoil will be high enough when it vis just boiling at atmospheric pressure without drawing heat too fast from the interior of the compress0rs.- Should, nevertheless, a higher temperature of the oil surrounding the compressors be found to be desirable, when working for instance with lighter oils as raw material, this caneasily be obtained by closing the valve in pipe 12 entirely and partly closing the valve in pipe 8, which will immediately put the whole interior of the still under pressure and consequently cause the boiling point of the oil in the still to risein proportion to the rise of the pressure.

Whenever the temperature in the producer has fallen so low that suflicient hydrogen is not formed, the gas current is switched so as to take the course via the cross line through valve 32 and all the other valves must be setagain so as to allow a reheating of the contents of the producer. As this procedure necessitates an interruption in the supply of fixed gas carrying a large percentage of hydrogen, it will be better to have two pro-- ducers, one running on the reheating phase while the other one is receiving the current of fixed gas for decomposition (not shown). Or, when working on a very large scale, the

producer plant for treating the fixed hydrocarbons ma be made altogether independent of the distil ing apparatus, and the latter may receive the prepared fixed hydrocarbons from a storage tank.

Though this process will produce the desired-light hydrocanbons by the use of pressures ranging between 100 and 200 pounds per square" inch, the reaction is greatly accelerated when the process is carried on at a pressure between one thousand and three thousand pounds. The use of such pressures in a common pipe or pressure still heated by direct fire is impracticable and dangerous, but perfectly practicable and safe when performed in the above described way. It must be understood, however, that with very high pressures care must be taken to see that the-heat created internally is rapidly removed and transferred to the oil surrounding the compressors. This can be effected either by the use of a larger number of compressors, so that compression will take place in more stages, by providing the compressors with cooling ribs, or by replacing the straight short pipes connectingone compressor with thenext one by long coiled pipes, sothat the temperature diiference between the interior of each compressor and the surrounding oil 1 taneously in contact with the oil surrounding the compressors. W

Should it be found to be desirable to know at any time the temperature at which the vapors escape from the last compressor,the pipe leading from it may be extended through the shell of the still and bent back into the interior again, the outside bend being provided with an opening X for the insertion of a pyrometer P, as shown in detail in Fig.2. This same figure also shows the automatic discharge valve in the end of pipe 24 replaced by a hand operated valve-Y, placed in an outside extension of the coil line, and so arranged that the contents of the coil are discharged back into the still. While not absolutely necessar these modifications will assist in the COIltI'OlYOfithfl process.

Having thus described my invention what I claim as newis: v

1. In the heating of oilby an apparatus comprising a still adaptedto contain a body of oil and a plurality of compressors connected in series and located within the oil, a process which consistsin compressing fixed hydrogen containing gas and oil va ors in successive stages to such a pressure t at the oil within the still will boil. 2. In the heating of oil by an apparatus comprising a still adapted to contain a body of oil and a plurality of com ressorsconnected in series and located wit in the'oil, a process which consists in compressingfixed ydrogen containingfgas and oil va ors in successive stages to such a pressure t at the oil within the still willboil, and transferring heat from the compressed products to the oil.

3. The process of producing hydrocarbons of low boiling points from hydro en con taining gas and hydrocarbons of high boilingp'oints by means of an apparatus comprising a closed still containing a body of oil and a plurality of compressors connected in series and located within the oil, which consists in mixin some of the vapors from the heated oil wit 1 hydrogen containing as and compressing the mixture within the ody of oil to a pressure of over two thousand pounds per square inch, permitting the compressed gases and vapors to escape into the oil at a pressure not less than two thousand pounds per square inch, withdrawing vapors and gases, separating the high boiling from the low boiling va ors and from the gases, separating the low iling va ors from the gases by condensation of the ormer, mixing the gases with hydrogen and returning the gaseous mixture to the com ressors.

4. The process of pro ucin hydrocarbons of low boiling points from iydrogen con taining gas and hydrocarbons of h gh boiling points by means of an apparatuscomprism ing a closed still containing a body of boiling oi and a plurality of compressors connecte in series and located within theoil and a gas enerator comprising a body of glowing caronaceous material, whichconsists in passing fixed hydrocarbon gas through the glowing l5 carbonaceous materlals whereby free hydrogen gas is formed, mixing a part of the vapors formed by the boiling f. oil with the mlxed hydrocarbon gas and hydrogen, subjecting the mixture thus formed to a pressure of over a two thousand pounds er square inch whereby hfydrocarbons simi ar to natural gasoline are armed, withdrawing vapors and gases separating the hi h boiling from the low v u bOlllIlg vapors an from the gases, separating the low boiling vapors from the gases by condensation of the former and returning the gases into the gas generator;

5. The method of producing hydrocarbons of low boiling points from hydrocarbons of high boiling points b means comprising a 1 gas generator adapte to contain a body of giowin carbon, a still adapted to contalii a dy 0 liquid hydrocarbons of highboilin point and-a multistage compressor located within the still and within the body of liquid hydrocarbons which consists in heating the liquid hydrocarbons to such a temperature thatthey will give off vapors and gases, ad-

mitting hydrogen into the vapor space above the liquid hydrocarbons so that a mixture of hydrogen and {hydrocarbon vapors and gases is formed, continuously withdrawing a' portion of the gaseous mixture and compressing a it to such a pressure that-the heat generate will raise the liquid hydrocarbons to a temperature above boiling, discharging the com- 1ressed gaseous mixture into the body of iquid hydrocarbons whereby the heat will 6 be more effectively transferred to the liquid hydrocarbons, conductin .va ors and ases from the space above the iqui hydrocar ons to a condenser, separating the condensates from the .fixed gases and then passing the ases through the gas generator whereby free ydrogen is produced. In testimony whereof I aflix my si ature.

PAUL DANCKWA DT.

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