US1923278A - Process and apparatus for treating hydrocarbons - Google Patents

Description

J. PERL Aug. 22, 1933.

PROCESS AND APPARATUS FOR TREATING HYDROCARBONS Original led e 1922 Patented Aug. 22, 1933 q PROCESS AND APPARATUS FOR TREATING HYDROCARBONS John Perl, Tulsa, Okla., assignor to Doherty Research Company, New York, N. Y., a Corporation of Delaware Application February 4, 1922, Serial No. 534,069

' Renewed March 5, 1929 19 Claims. (Cl. 196-58) v My invention relates to the treatment of hyspace of the vaporizing chamber 8, preferably drocarbon oil and more particularly to the utiliextending nearly the whole length of said chamzation of the so called fuel oil and heavier fracber and being provided with openings therein. tions resulting from the commercial cracking of The vaporizing chamber 8 has a vapor dome,

petroleum. In the ordinary processes of con- 12, with baffle plates therein and is provided with 60 verting heavy hydrocarbon oils into lighter hyan outlet pipe 14 for the vapor which communidrocarbons, there is a breaking down of the heavy Oates with suitable condenser and run down tank saturated hydrocarbons into lighter parafiines (not shown) and is provided with a suitable reand olefines, and under the influence of heat and iiucing valve 15 and other fittings in accordance pressure and other agencies usually present in with common practice.

commercial. processes, there is a tendency for the The bottom portionof the vaporizing chamber olefines to polymerize, and there is also a tend- 8 is provided with a pipe 16, equipped with a suitency to produce free carbon and permanently able reducing valve 17, which opens into a vaporgaseous hydrocarbons. The so-called fuel oil is izing chamber 18 and is provided with a suit- 15 an intermediate product or lay-product of ordiable spraying nozzle 19 inside of said chamber 7 nary commercial treatment of petroleum, and to spray and facilitate the evaporation of the here-tofore it has defied economic conversion liquid. The upper portion of this vaporizing into more desirable and lighter products. chamber 18 has a pipe 20 which communicates The principal object of my invention is to dewith a condensing coil 21 and thence with a con- 20 vise a process for the economic treatment of pe densing chamber or receiver 22, with which are 75 troleum or hydrocarbon oils that will minimize associated a suitable level indicator 23, level regupclymerization and enhance the production of lator 24 and float regulated valve 25, which latter desirable and lighter products; and another obcontrols the flow of the condensed liquid into the ject is to devise a process for the successful and storage tank 26. The bottom of said vaporizing 25 economical treatment of fuel oils and the like. chamber 18 communicates by a pipe 2'7, having a 0 The invention consists in the process and in the coiled portion 28 inside a cooling chamber 29, apparatus hereinafter described and claimed. with a constant level siphon chamber 30; and the In the accompanying drawing, Fig. 1 represents siphon chamber is provided with a funnel-shaped an apparatus suitable for practicing my process; overflow 31 that is provided with an outlet pipe 30 and that extends into the bottom portion of an ac- Fig. 2 represents a modification thereof. cumulator tank 32 that is provided with a suit- As illustrated in the drawing, my apparatus able level indicator 33, level regulator 34 and comprises a furnace or heater 1, a heater coil 2 float regulated valve 35 in an outlet pipe 36 that mounted therein and connected by a pipe 3 to a leads into a suitable storage tank (not shown).

a suitable source of supply of fresh oil and also In order to prevent back pressure in the vaporconnected on the delivery side by a pipe 4 to one izing chamber 18 from disturbing the action of end chamber of a converter or heat exchanger 5 the siphon, the upper portion of the siphon chamwhich communicates with the opposite end ber 30 is provided with a pipe 3'7 which communichamber thereof through a multiplicity of tubes cates with the upper portion of the receiver 22.

40 6 mounted therein in suitable tube sheets. The The condenser coil 21 is preferably mounted opposite end chamber of said converter or'heat in a pipe system 38 which communicates at the exchanger is provided with a delivery pipe I which bottom through a pipe 39 with the storage tank projects into the vapor space of a vaporizing 26 or other suitable source of oil supply, and on chamber 8 and is provided with a series of jet the other side it preferably communicates with 45 openings in. the portion of said pipe inside of the fresh oil supply pipe 3 that supplies fresh oil said vaporizing chamber. The middle chamber to the heater coil 2.

9 of the heat exchanger, that is, the portion be- The operation of v the above described appatween the tube sheets and enclosing the tubes 6, ratus is as follows: The fresh oil is passed has a supply pipe 10 that extends from the lower through the pipes 38 surrounding the condenser 50 portion of the vaporizing chamber 3 into the coil 21 and there absorbs considerable heat from lower portion of said heat exchanger chamber, the coil and, after this initial heating, it passes preferably near one endthereof. A second pipe directly into the heating coil 2 of the furnace.

11 extends from the upper portion of said heat As the primary object of the furnace heat is to exchanger chamber, preferably near the oppo crack the fresh oil, it is run at a temperature suitsite end thereof, and extends into the liquid able for this. purpose, which temperature will vary more or less with the nature of the oil and the pressure in the pipe, as is well known in the art of cracking petroleum. The products resulting from the cracking of the fresh oil in the heater pass through the heat exchanger 5 and into the vaporizing chamber 8. It is desirable that the temperature of the cracked oil products at the time they enter the exchanger shall not greatly exceed 850 F., in which case such productsv will enter the vaporizing chamber at a temperature in the neighborhood of 750 F. The lighter products will pass out from the vaporizing chamber through the vapor dome and the delivery line for condensation and storage in accordance with usual practice. The products of the cracking operation that enter the vaporizing chamber 31in a liquid form fall into the liquid space ,of said vaporizing chamber and commingle with the other liquid therein. This liquid circulatesfrorri the bottom portion of said vaporizing chamber to the converter or heat exchanger, where it is brought under the influence of the heat exchanger tubes, that are .being heated by the cracked products fresh from the heater, and thence back into the liquid space of said vaporizer. At the same time, a portion of such liquid is being continuously eliminated into the vapor space of the vaporizing chamber 18 through the nozzle 19 therein; and as the pressure in the vaporizing chamber 18 is considerably less than that in the vaporizing chamber 8, a considerable portion of the liquid that enters the vaporizing chamber '18 will immediately vaporize and pass off through the oil-cooled condenser 21 .and thence to the storage tank. The liquid residue in the vaporizing tank 18 is drawn on by a siphonic action into the accumulator tank. The ordinary furnace temperature is in the neighborhood of 2400 F. and the temperature of the flue gases that come in contact with the cracking coils usually is in' the neighborhood of 1500 to 1600 .11, whereas the average oil temperature at the cracking phase is in the neighborhood of 700 to 750 F. Under these conditions, there is a tendency to overheat the oil in the cracking coils, especially the film of oil in immediate contact with the metal, and thus bring about the formation of free carbon, permanent gases and the polymerization of the olefines resulting from the normal cracking operation.

According to the present invention, the fresh oil is passed under pressure (say, from 100 to 500 pounds) through the cracking coils with sufficient rapidity to keep the temperature of the general mass below the point at which polymerization of the olefines iscaused. While there may be some polymerization of the resulting olefines, the polymerizing action is limited to the formation of single phase or mono-polymerides, and these are dissolved in the complex liquid and leave the heating coils in solution. When this complex liquid reaches the vaporizing chamber 8 and the lighter fraction thereof is drawn 011. through the vapor line, the residue becomesmore susceptible to the action of heatr so that, when such residue circulates back through the heat exchanger, its heavier components are readily broken down by the hot products of the cracking operation into lighter products, some of which pass off, when they reach the vaporizing chamber,

intothe vapor dome and vapor line.

As an example of the practical operation of my process, I may take a hydrocarbon oil of 32 Be. and treat it at a cracking temperature of 800 F. Usually,

the fraction that is removed from the first vaporizing tank 3 through the vapor line is gasoline or naphtha of a gravity of about 49.8 B., and amounts to about 32 per cent. of the quantity of fresh oil treated. The residue is the portion that is most subject to polymerization and other ill eiiects of excessive heating; and this residue is circulated through the heat exchanger where it is continuously exposed to the heat of the newly cracked products coming directly from the furnace coils at a temperature of from 800 to 850 F. This temperature is sufficient to break down much of the residue above mentioned but is insufiicient to bring about any considerable polymerization thereof and does not cause the production of free carbon or permanent gas in any considerable quantity. In this connection, it is noted that the heating of the residue by thenewly cracked products is by conduction, Whereas the heating of the fresh oil in the heater coils is largely due to radiant heat, which is far more rapid and more destructive in its action on the'oil. Thus, by treating the residue with the heat of conduction from the newly cracked products fresh from the furnace coils, great uniformity of temperature is obtainable, and the breaking down of this residue in the heat exchanger is accomplished with economy and under very favorable conditions for production of desirable products in large volume and without the production of undesirable products. In the example given, the residue above mentioned, would amount to about per cent. of the initial volume of the oil, and would have an average specific gravity of about 21 B. in comparison with an initial gravity of 32 B. of the fresh oil. As a result of the treatment above described, this residue, which passes. into the second vaporizing chamber 18, is there separated into two fractions; one of which passes off as a vapor and is condensed into a liquid whose gravity is about B. and Whose quantity is about 38 per cent. of the original volume of the fresh oil. The other fraction is a liquid whose specific gravity is about 16 B. and whose quantity amounts to about 25 per cent. of the original volume of the fresh oil.

The apparatus illustrated in Fig. 2 is especially designed for the treatment of raw fuel oil. In this modification, the apparatus is substantially the same as above described except that the evaporating chamber 8 is wholly disconnected from the middle chamber of the heat exchanger 5 and its place, in this particular, is taken by an additional vaporizing chamber 8 similarly connected and equipped. In this modification, the middle chamber of the heat exchanger 5 is supplied directly from a suitable source of raw fuel oil by a supply pipe 4 and the opposite ends of middle chamber of said heat exchanger are connected to the vaporizing chamber 8 by means of pipes 10 and 11 especially provided therefor, which vaporizing chamber is provided with a vapor outlet line 14 and with a pipe 16 for delivering its liquid residue into the vaporizing chamber 18 along with the residue from the evaporating chamber 8. In this modification, the raw fuel oil is introduced from the source of supply through pipe 4 into the middle of the heat exchanger 5 where it is subjected to the heat of the freshly cracked products that pass through the tubes therein at a temperature in the neighborhood of from 750 to 850 degrees F. The products resulting from the heating of the fuel oil pass out through the pipe 11 and are delivered through the jet openings thereof into the vapor space of the vaporizing chamber 8 under pressure of say, from 100 to 150 pounds. The vapors pass out through the vapor line in the usual way. Part of the liquid residue flows back into the mid-' dle chamber of the heat exchanger for treatment therein, and the remainder flows into the vaporizing chamber 18 either through a separate valved pipe 16 or through the same valved pipe 16 that delivers the residue of the evaporating chamber 8. If desired, the products resulting from the treatment of the fuel oil may be kept separate from the products of the pyrogenously. cracked oil by duplicating that portion of the system illustrated in Fig. 1 through which the oil passes after leaving the heat exchanger.

The operation of the apparatus illustrated in Fig. 2 is similar to that illustrated in Fig. 1, except that the heavier fraction or first residue of the cracking of the lighter or pyrogenously cracked oil is not treated in the heat exchanger but passes directly from the first vaporizing chamber 8 through the reducing valve into the second vaporizing chamber 18. While the sec ond residue may contain polymerides, they are of low order and readily soluble in the liquid and need not be removed to fit the liquid for a base suitable for manufacturing lubricating oils. The raw fuel oil is passed through the heat exchanger, where its heavier ingredients are broken down to lighter hydrocarbons and the complex liquid containing them circulates in the vaporizing chamber 8 from which the lighter products pass off through the vapor dome and the vapor line. The heavier products are partly returned from the vaporizing chamber 8 to the heat exchanger for further treatment and partly pass out through the reducing valve into the second evaporating chamber 18, where the lighter fraction thereof is evaporated and separated from the heavier fraction. As the cracking of the fuel oil is done by the heat of conduction from the cracked products of the lighter oil, the danger of overheating the fuel oil is avoided and a maximum production of valuable products is obtained therefrom.

What I claim is:

l. The process of cracking hydrocarbon oils which comprises continuously passing oil stock to be cracked through a heating and cracking zone in which the oil is cracked at high temperature, conducting the resulting highly-heated products while at a high temperature from said zone into a heat exchanging zone in which the highly heated products are utilized for indirectly heating and cracking a heavier hydrocarbon oil continuously passed therethrough, and separating vapors formed by the heating and cracking of the oil in said heating zones from any unvaporized oil constituents remaining from the heating in said zones.

2; The process of treating hydrocarbons which comprises pyrogenously cracking the same, separating the light fraction from the heavier fraction thereof under pressure, reheating the heavier fraction by the heat of the newly formed prodnets of said pyrogenous cracking and eliminating under pressure the lighter fraction thus formed, separating the residue into lighter and heavier fractions by evaporation under reduced pressure.

3. The process of treating hydrocarbons which comprises pyrogenonsly cracking the same, separating the light fraction from the heavier fraction thereof under pressure, circulating the heavier fraction through a heat exchanger heated by the hydrocarbons fresh from the pyrogenous cracking operation and eliminating under pres-. sure the lighter fraction thus formed, and separating the residue into lighter and heavier fractions by evaporationunder reduced pressure.

4. The process of treating hydrocarbons which comprises the pyrogenous cracking thereof in a continuous stream, passing the entire stream of resulting products through a heat exchanger and thence to an evaporating chamber wherein pressure is maintained, eliminating from said evap crating chamber under pressure the lighter fraction resulting from the cracking of said hydrocarbons, passing part of the heavier fraction through said heat exchanger out, of contact with the stream of newly formed products and back to said evaporating chamber, withdrawing from said evaporating chamber a portion of the heavier content thereof and eliminating its lighter fraction from said portion under a pressure lower than that of said evaporating chamber.

5. Apparatusjfor treating hydrocarbons comprising a heating coil, a heat exchanger having one of its chambers connected with said heating coil; an evaporating chamber connected with said chamber of said heat exchanger to receive the hydrocarbons thereof, a second evaporating chamber connected to said first evaporating chamber, and a reducing valve in the connection between said chambers, said evaporating chambers having vapor outlet lines and said second chamber having a line for delivering the liquid residue therefrom, and means for circulating oil from said first mentioned evaporating chamber through a second chamber of said heat exchanger to be heated thereby without commingling with the supply direct from the heating coil and thence back to said first mentioned evaporating chamber.

6. Apparatus for treating hydrocarbons com prising a heating coil, a heat exchanger connected therewith, an evaporating chamber connected with said heat exchanger to receive the hydrocarbons therefrom, a second evaporating cham-, ber connected to said first evaporating chamber, and a reducing valve in the connection between said chambers, said evaporating chambers hav ing vapor outlet lines and said second chamber having a line for delivering the liquid residue therefrom, and means for circulating oil through said heat exchanger to be heated thereby, said means comprising pipe connections between said heat exchanger and the liquid space of said first mentioned evaporating chamber.

7. Apparatus for treating hydrocarbons comprising a heating coil, a heat exchanger connect ed therewith, an evaporating chamber connected with said heat exchanger to receive the hydrocarbons-therefrom, a second evaporating chamber connected to said first evaporating chamber, and a reducing valve in the connection between said chambers, said evaporating chambers hav-- ing vapor outlet lines and said second chamber having a line for delivering the liquid residue therein, and means for circulating oil through said heat exchanger to be heated thereby, said means comprising a supply pipe for supplying the oil to be heated to said heat exchanger and an outlet pipe for such oil extending from said heat exchanger to a third evaporating chamber.

8. Apparatus for treating hydrocarbons comprising a heating coil, a heat exchanger connected therewith, an evaporating chamber connected with said heat exchanger to receive the hydrocarbons therefrom, a second evaporating chamber connected to said first evaporating chamber,

and a reducing valve in the connection between said chambers, said evaporating chambers having vapor outlet lines and said second chamber having a line for delivering the liquid residue therein, and means for circulating oil through said heat exchanger to be heated thereby, said means comprising a supply pipe for supplying oil to be heated to said heat exchanger .from' said first mentioned evaporating chamber and an outlet pipe for such oil extending from said heat exchanger to said first mentioned evaporating chamber.

9. The process of cracking petroleum oil, which comprises passing the oil to be treated through a heating zone wherein the oil is heated to cracking, conducting the highly heated products from said heating zone through a heat exchange zone and into a vaporizing .zone, and

passing unvaporized oil from said last mentioned zone through said heat exchange zone to be heated by said highly heated oil by indirect heat exchange therewith.

10. The process of cracking hydrocarbon oils, which comprises heating oil to a cracking temperature in a heating zone and passing it through a heat exchange zone and then into a vaporizing zone maintained under a superatmospheric pressure, conducting unvaporized oil from said last mentioned zone through said heat exchange zone and returning the same to said vaporizing zone, withdrawing residuum from said vaporizing zone into a second vaporizing zone maintained under a lower pressure than said first-mentioned vaporizing zone and vaporizing substantial quantities of said residuum therein, conducting vapors from said second vaporizing zone to a condenser, and passing the resulting condensate into the heating zone, for conversion into lower boiling products. y

11. The process of converting higher boiling hydrocarbons into lower boiling products, which comprises heating and cracking a high boiling oil in a heating zone, conducting the resulting oil through a heat exchange zone and theninto a vaporizing zone, passing unvaporized oil from said vaporizing zone through said heat exchange zone to further heat and crack the same, passing unvaporized residue from said cracking operations into a residue vaporizing zone maintained under a lower pressure than said first mentioned vaporizing zone and vaporizing substantial quantities of said residue therein, condensing the vapors produced in said residue vaporizing zone and passing the resulting condensate into the said heating zone.

12. The process of converting hydrocarbon oils into lower boiling products, whichcomprises heating and cracking a hydrocarbon oil in a heating zone and conducting it while at a high temperature through a heat exchange zone, passing a heavier hydrocarbon oil in indirect heat exchange with the highly heated oil in said heat exchange zone thereby to heat and crack said heavy hydrocarbon oil, and vaporizing portions of said cracked oils by introducing the same into a vaporizing zone maintained under a pressure lower than the pressure maintained on the oil during said cracking.

13. In the pyrogeneous cracking of petroleum oils; the process which comprises maintaining a body of oil in an enlarged cracking chamber at a cracking temperature and under a superatmospheric pressure, passing oil from said chamber through ,a heating zone and back to said chamber, withdrawing portions of the oil from said chamber into a vaporizing zone. main tained under a lower pressure than that maintained in said chamber and vaporizing substantial portions of the oil introduced into said zone, condensing a stock for recracking from the vapors formed in said vaporizing zone by passing them in heat exchange with condensate previously, formed from the vapors from said vaporizing zone, heating said stock in a second heating zone to a high cracking temperature, utilizing. the resulting highly heated products for indirectly heatingthe oil from said chamber in said first-mentioned heating zone, and introducing the'said'products into said enlarged chamber.

14. The process of cracking hydrocarbon oils, which comprises passing oil in a closed cycle from an enlarged body of oil in a cracking zone through a heating zone in which the oil is heated to a cracking temperature and .then back into said cracking zone, thereby to maintain said body of oil at a cracking temperature, maintaining the oil of said body under a substantial superatmospheric pressure, withdrawing residuum from said body into a vaporizing zone maintained under a lower pressure than the pressure maintained on the oil of said body and in which vaporization of substantial portions of said residuum is effected by the heat contained therein, condensing the vapors evolved from said residuum, passing the condensate produced from said vaporsthrough a separate heating zone in which it is heated to a cracking temperature, and passing the resulting products into said cracking zone.

15. The process of cracking hydrocarbon oils, which comprises passing oil in a closed cycle from an enlarged body of oil in a cracking zone through a heating zone in which the oil is heated to a cracking temperature and then back into said cracking zone, thereby to maintain said body of oil at a cracking temperature, maintaining the oil of said body under a substantial superatmospherie pressure, withdrawing residuum from said body into a vaporizing zone maintained under a lower pressure than the pressure maintained on the oil of said body and. in which vaporization' of substantial portions of said residuum is effected by the heat contained therein, condensing the vapors evolved from said residuum, passing the condensate produced from said vapors through a second heating zone in which it is heated to a cracking temperature, and passing the resulting products while in a highly heated state in heat exchange but out of direct contact with the oil being passed through said closed cycle and then into a second enlarged cracking zone.

16. The process of cracking relatively heavy hydrocarbon oils, which comprises passing such oil through a heating zone in which the oil is heated to a cracking temperature, passing the resulting products into an enlarged cracking zone in which vapors are separated from unvaporized oil residuum, maintaining a substantial superatmospheric pressure on the oil constituents in said enlarged zone, Withdrawing reisduum from said enlarged zone into a reduced pressure vaporizing zone in which substantial portions of the residuum introduced thereinto are vaporized by heat contained therein, condensing vapors formed from said residuum, passing the resulting condensate through a second heating zone in which it is heated to a high cracking temperature, passing the resulting products from the heating of said condensate while in a highly heated state in indirect heat exchange with the oil passing through the first-mentioned heating zone and then into a second enlarged cracking zone in which vapors are separated from unvaporized oil, maintaining a substantial superatmospheric pressure in said second enlarged zone, withdrawing unvaporized oil constituents from said second enlarged zone into said reduced pressure zone, and therein vaporizing substantial portions of the unvaporized oil to aid in supplying said condensate.

1'7. The process of cracking hydrocarbon oils, which comprises passing an oil distillate cracking stock in a confined stream through a heating zone, heating the said stock in said zone to a cracking temperature and cracking the same while in said zone, passing the highly heated products of said stock from said zone into heat exchange but out of direct contact with relatively heavy fresh oil charging stock thereby to substantially cool the products from said zone and heat said heavy fresh oil stock to a temperature suflicient to vaporize substantial portions thereof, passing the products cooled by said heat exchange into an enlarged vaporizing zone, vaporizing portions of said fresh oil stock heated by said heat exchange, condensing the said vaporized portions to form a distillate suitable as a cracking stock and conducting the same to said heating zone to form at least in part the said distillate cracking stock for said zone.

18. In the pressure distillation of oils heavier than gasoline for the production of gasoline-like products, forcing oil through a heating zone into a maintained pool, thereby bringing the oil to conversion temperature and maintainingthe pool at conversion temperature, discharging liquid products from said pool to another pool, removing oil continuously from the latter pool, the oil passing from the heating zone to the first pool being led in a confined stream and through the latter pool in indirect heat conductive relationship with the liquid contents thereof.

19. The process of pyrogenously cracking petroleum oils which comprises heating and cracking the oil under superatmospheric pressure, passing the resulting highly heated liquid and vapor products through a cooling zone and then into a separating zone where vapors and liquid products are separated and wherein a substantial body of oil is maintained under cracking conditions of temperature and pressure, conducting portions of the liquid products directly from said separating zone back into said cooling zone in indirect heat exchange with the highly heated oil constituents passing therethrough, thereby to reheat and effect distillation of portions of the liquid products returned to said cooling zone.

JOHN PERL.

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