US1712789A - Process for the conversion of hydrocarbon oils - Google Patents

Description

y 1929- J. F. DONNELLY PROCESS FOR THE CONVERSION OF HYDRQCARBON OILS Filed Nov. 21, -1924 ,[IzLenZEr FDOIIrzeZQ- Patented May 14, 19 29.

JOSEPH F. DONNELLY,

OF LEMONT, ILLINOIS.

PROCESS FOR THE CON VERSION OF HYDROCARBON OILS.

Application filed November 21, 1924. Serial No. 751,250.

This invention relates to a process for the conversion of hydrocarbon oils. By conversion I refer to what is-commonly known as cracking involving an atomic change in the molecular structure.

It is an object of my invention to effect this conversion in such a manner that the final products possess chemical characteristics more nearly a proxima'ting those of the natural lIydIOCZLIXHI oils than have heretofore been produced by cracking processes.

Another object is to effect the production of the desired lighter end products without reducing the heavier products of conversion to the form of free carbon or coke.

Another object is to separate the residue from the products which it is desired to resubject to the conversion cycle and keep the residue in liquid solution by adding thereto lighter solvent oils in such quantity as will prevent the residue from being reduced so as to prevent the formation of tar and keep the liquid residue at such a temperature as will check cracking therein in such a manner as to avoid the fomnation of solid end products such as free carbon and coke.

Another object is to establish such physical condition of operation that the formation of free carbon in the apparatus during its cycle of treatment is avoided. I

Another object is to prevent the occur rence of total decomposition particularly in the heavier constituents which constitute marketable products, such as fuel oils, lubricating oils and waxes, which have been separated out or synthetically formed by polymerization in the zone of lower pressure.

Other objects and advantages of my invention will appear hereinafter.

In order to render my invention clear, reference is had to the accompanying drawing";

in which I disclose one form of apparatus capable of carrying out my process, in which the figure is a side elevation, partly in section, of said apparatus.

In the drawing, 1 is a pipe still provided with afurnace 2 and a continuous coil 3. The liquid oil is delivered to the coil under pressure by a pump i, through a-conduit 5. Pressure gauges are shown at 6. The heated oil under pressure is delivered from the coil 3, through a conduit 7, into the outer end of an expansion chamber 8. The heated oil from the conduit .7 passes into the chamber 8 through a valve cont-rolled nozzle 9. The chamber 8 is located Within a base tank 10,

denser 25 to a suitable run-down tank and extending outwardly from the chamber 8 to a point near the bottom of the base tank are a series of outlet conduits 11. From a low point on the base tank 10, a vulva-controlled conduit 12 leads to a spacewithin the chamber surroundm g the-nozzle 9 at a point to the rear of the delivery end of the said nozzle.

The oil under high velocity leaving the nozzle 9 draws up the residue oil from the tank l0 and mixes it with the stream of expanding oil or vapor issuing from the nozzle 9. To the conduit 12 is connected a valvecontrolled conduit 13 which leads to a pump 14. A valve-controlled delivery pipe 15 leads from the pump 14; to the conduit 12. By closing the control-valve in the conduit 12 and opening the control valves in conduits 13 and 15, the pump 14 may be operated to draw oil from the tank 10 and deliver it to the chamber 8 through the delivery end of the conduit 12. Thus, the delivery of oil from the tank 10 tothe chamber 8 may be effected by suction or forced feed by pump 14. A series of valve-controlled draw-ofi's from the tank 10 are shown at 16.

Mounted on the base tank 10 is a condensing column 17. The column 17 has an upper tubed section 18 and a lower tubed section 19. Between the sections 18 and 19 is a trap 20. The trap 20 collects the condensates from the upper section 18 and delivers them through a valve-controlled conduit 21 into a reflux chamber 22 formed in the tank 10 by a partition 23. A vapor outlet leads from the top of the chamber 22 to the upper end of the trap 20 as shown. A vapor outlet conduit .24 leads from the top of the column 17 to a final condenser 25. A delivery conduit 26 conducts the final condensates from the con- (not shown).

For the purpose of controlling the temperature of the condensers 18, 19 and 25, water is fed through a valve-controlled conduit 27- into the jacket surrounding the tubes of the condenser 25. From the condenser water is led through conduit 28 and valve-controlled branch conduits 29 and 30 into the jackets surrounding the tubes of sections 18 and 19 respectively. From the lower end of the jacket of section 18, an outlet conduit 31 conducts the water to a valve-controlled discharge conduit 32. A valve-controlled branch conduit 33 connects the conduit 31 with the upper end of the jacket surrounding the tubes of section 19, and a valve-controlled outlet conduit '34 connects the lower end of this jacket iwith the out-flow conduit 32. By this system of water conduits and control valves, the operating temperatures of the condenser and sections 18 and 19 may be controlled at will.

By opening the valves in conduits 29, 33 and 34 and closing the valves in conduits and 32, the cooling water will be caused to flow first through the jacket of section 18, thence through the jacket of section 19, and be discharged through the conduit 34 into the conduit. 32. It will be apparent that the water passing through the condenser 25 and section 18 will be more or less heated when arriving at the section 19. I have therefore provided an inlet from the conduit 28 direct to the section 19, namely, the branch conduit 30. By opening the 'valves in conduits 30 and 34 and closing the valve in conduit 32, the cooling water may be passed direct from the condenser 25 to the section 19. It will thus be seen that by proper manipulation of the valves in conduits 29, 30, 32, 33 and 34,

some or all of the cooling water from the condenser 25 may be passed through section 19 and likewise some or all of the water from section 18 may be passed through section 19.

The reflux chamber 22 is provided with a fresh oil supply conduit 35 in which is placed a float-controlled valve. By this means the fresh charging stock is fed into the chamber 22 in such a manner as to keep a constant liquid level therein.

The chamber 22 is also provided with a valve-controlled outlet conduit 36, which leads to the inlet of the pump 4. A valv.e controlled conduit 37 connects the conduit 36 with the base tank 10 at a point to the right of the partition 23. Manholes are provided in the base tank 10 at 38 and 39 respectively. Thermocouples are provided at 40 to indicate the temperatures at the points shown.

In starting up, the operation is as follows:

Charging stock is fed through the conduit 35 into the chamber 22, and thence through the conduit 36 to the inlet of the pump 4. The pump 4 delivers. the oil to the coil 3, where it is'heated by the furnace 2. From the coil 3, the oil is delivered through conduit 7 to the nozzle 9, where it is delivered into the chamber 8, and thence through the outlets 11 into the base tank 10. When the base tank is filled to the desired level, the valve in conduit 37 is opened and the surplus oil fed to the conduit 36, and back to the inlet of the pump 4. This operation iscontinued until the proper temperatures and pressures are reached, at which time the flow to the conduit 37 will be cut off.

In normal operation, a pressure will be maintained on the oil in coil 3 and conduits 5 and 7 by the pump 4, which will prevent ebullition thereof with consequent formation permitted to escape through the valve-controlled nozzle 9 at high velocity into the chamber 8, which constitutes part of and is in open communication with a zone of lower pressure. The pressure on the oil thus being suddenly released permits the heat which is stored therein to become effective to suddenly cause a transformation of the li uid oil which has been heated to or above its oiling point.

\ at the reduced pressure, into the gaseous formation. Under ordinary circumstances, this sudden expansion of the oil by reason of its change from the liquid to the gaseous state would result in aseparation of the lighter from the heavier products, and the continued cracking reaction due to the heat stored in the oil would progress into total decomposition of a portion of the hydrocarbon bodies in such a manner as to leave free carbon or coke as av apparatus herein shown, I have provided two means of introducing this cooler oil. One of such means consists of the conduit 12, which conducts the cooler oil from the base tank to a point to the rear of the-discharge end of the nozzle 9. The vacuum caused by the rapidly expanding oil under velocity from the nozzle 9 draws the oil through the conduit 12 and introduces it into the expanding oil within' the chamber 8. The other means consists of a forced feed of cooler oil from the base tank to the same point by means of the pump 14. When the pump is operating, the valves in the conduits 13 and 15 are opened, and the valve 7 in the conduit 12 is closed.

In the apparatus herein shown, the cooler oil which is introduced into the chamber 8 is drawn from the base tank, but it is within the scope of my invention to draw cooler oil from an outside source, in which case the oil so used may be of any nature suited to the intended purpose. If desired, I may inject water or steam into the chamber 8 to effect a regulation of the temperature therein.

I may also inject heated oil from the still 3 directly into the residue oil within the large tank 10, in which case the temperature of the residue oil will be maintained at a point which will control the vaporization and cracking of the-oil from the still in a man-' compounds by heat is explained on the basis of the occurrence of intermolecular collisions of such violence that the bonds holding together the various atoms or groups are ruptured. The degreeof cracking varies as the temperature to which the substance is heated varies. This explanation is supported by the well-established kinetic theory of gases. When the temperature reaches the degree to cause the necessary rate of molecular vibration, and said rate of vibration is continued, cracking will progressively continue. If the time and temperature are continued further the cracking reaction will. progress into a more complete or total decomposition of a portion of the hydrocarbon constituents, resulting in the formation of free carbon which will mass together forming coke if allowed to become quiescent.

In my process the oil "is heated to a cracking temperature for a sufiicient length of time to effect cracking while held in liquid form by sufficient pressure for this purpose.

It is therefore an object of my process to heat the oil to the desired cracking temperature for sufficient time to cause the desired amount of cracking under an imposed pressure sufficient to prevent the vaporization thereof and subsequently to release the heated oil into a zone of lower pressure with resultant vaporization by the internally stored heat Within the oil accompanied by simultaneous cracking due to its temperature which has not been reduced by expansion and vaporization below the cracking temperature thereof and to check the cracking by reducing the temperature of the heated oil in such a manner that the cracking reaction does not progress into total decomposition with the consequent formation of solid end products such as free carbon or coke.

It is also my purpose to prevent the reduction of the high boiling constituents. appearing in the zone of lower pressure to the form of solid end products such as free carbon or coke. Such solid end products would ordinarily appear upon the tot-a1 decomposition of portions of such high boiling constituents due to the temperature thereof combined with the length of time said constituents would normally be subjected to said temperature in said zone of lower pressure. a It is therefore an object of my process to prevent the reduction of such higher boiling oils to a condition wherein solid end products'such as coke or free carbon are formed by reducing the temperature thereof in sucha manner that total decomposition is avoided.

In my preferred form herein disclosed I effect this temperature control by th'e introduction of condensates into the mass of oil in the base of the tower which not only maintains the proper temperature of the oil in said base to prevent the formation of solid end products due to total decomposition, but also adds oils of a character which keep the residue in a liquid condition. These condensates thus introduced are continuously revaporized thus extracting heat from said higher boiling oils. The vapors thus formed are continuously removed from said higher boiling oils, condensed and returned into said higher boiling oils in the base of the tower.

The products from the chamber 8 are fed into a body of oil in the base tank 10 through the conduits 11 and undergo a heatinterchange therewith, resulting in the vaporization of .those constituents that are vaporizable at the temperature at which the oil in the base tank is maintained.

In order to return the condensates to the base tank l0for the purposes described, I

have provided the condenser section 19 and cooling apparatus as heretofore described.

By suitable regulation of the supply of cooling water to the jacket of the section 19, I am enabled to return to the base tank the necessary amount of condensates at the propor temperature for the purposes set. forth. The condensates from sectionl8 are collected in the trap 20 and are passed to the chamber 22. Any vapors which are formed in the chamber 22 pass to the condensing section 18 and final condenser 25. The liquid in chamber 22 is heated by a heat interchange with the liquid on the other side of the partition 23, and this heating will effect a dchydration of the oil in chamber 22, which is composed of fresh charging stock and condensensatcs from the condenser 18. The liquid from chamber 22 is recycled by sending the same through conduit 36 to the pump 4. The recycled oil is composed of a mixture of dehydrated fresh oil and'selected condensates unmixed with the residue oil.

-By means of the pressure and temperature indicating devices and qualitative tests of the products, the operator may readily guide the process so as to produce the desired results. The control of the cracking reaction in the coil 3 pipe 7, chamber 8 and base tank 10 may be readily accomplished by the operator. It is well known to those skilled in the art that as soon as a cracking reaction rogrosses into total decomposition gases Wi 1 be evolved. It is also well known to those skilled in the art that even though the cracking temperatures are above the range of the critical temperatures of many 'of the lighter hydrocarbons, nevertheless the vapor pressure of these substances is very much lowered by the fact that they are in solution in a fairly large body of heavy'hydrocarbon oil. \Vith sufficient pressure, t erefore, it is pos sible tomaintain in a liquid phase in decomposing heavy oils even thou h the tempera tures employed are above the critical temperatures of some of-the. hydrocarbons produced by decomposition. I have also determined that the cracking reaction-can be carried on for a much longer period before total decomposition sets in if vaporization is prevented by superimposed pressure. I have observed in practical operation that as long as the oil in the coil 3 remains in liquid phase the strokes of the pump 4 are positively indicated by a corresponding oscillating deflection of the indicating needles of the pressure gauges 6. If through improper operat-' mg conditions gases or vapors should accidently be formed in the coil 3 their presence will be immediately reflected by a strong advance of the pressure indicating needles of the gauges 6 and with accompanying cessation of the oscillation thereof. The accidental occurrence of gases or vapors in the coil may be immediately remediedby a de crease of fire box temperatures but is Preferably accomplished by an opening of the valve. controlling the expansion nozzle 9 and speeding up the strokes of the pump 4 which causes a greater volume of oilto pass through the coil 3 which reduces the time of exposure of the oil to the. heat. By maintaining a liquid phase reaction in the coil 3I am enabled to effect a commercial amount of cracking therein before it becomes necessary to further control the cracking reaction by temperature reduction to prevent it from proceeding into a condition where total decomposition of a portion of the oil is effected with consequent formation of free carbon.

7 In applying tests in order to guide my process so that free carbon will not be formed in the cracking reaction, I proceed as follows. The oil is heated under a gradually increasing temperature and under an extraneous applied pressure in excess of the vapor tension of the oil being treated until the oil leaving the conduit 7 reaches a temperature of 700 to 800 degrees F. at which temperature samples of the oil are withdrawn from the conduit 7 and tested for free carbon. The temperature is then gradually increased on the oil being treated until the free carbon test shows traces of free carbon. Then the flow is increased-on the oil stream thus reducing the temperature of the oil being treated until no trace of free carbon is foundby the" applied test. I also test samples of oil drawn from the base tank 10. If the test shows traces of free carbon I increase the speed of the cooling of the heated oil in the zone of lower pressure by reducing the temperature of the condenser section 19, thereby deliveringcooler condensates in a greater quantlty into the base tank 10 until the free carbon test of the oil therein shows that the desired result of checking the crackin reaction before the formation of free caidoon has been accomplished. The free carbon test of the oil in the base tank 10 will indicate whether free carbon is being formed in any part of the cracking reaction, since, if such is the case, free carbon will ultimately appear in and be detected by the free carbon test of samples taken from the base tank 10.

It will thus be seen that I have provided a process in which the cracking reaction is conducted in such a manner that total decomposition with its attendant formation of freecarbon or coke is avoided in the successive steps-thereof in an eflicient and easily controlled manner.

Having described my invention, what I claim is:

1. A process for the conversion of hydrocarbon oils, which consists in heating a mass of relatively heavy hydrocarbon oil to a cracking temperature under a pressure sufiicient to prevent vaporization thereof, dis charging said heated oil before the cracking reaction reaches the condition where free carbon would beformed therein into a zone of lower pressure, and checking the cracking reaction in said zone of lower pressure before it reaches the condition where free carbon would be formed therein, in such a degree as to prevent the formation of free carbon in said zone by the simultaneous regulated introduction of a cooler hydrocarbon oil into said zone. i

2. A process for the conversion of hydrocarbon oils, which consists in heating a mass of relatively heavy hydrocarbon oil to a cracking temperature under a pressure suflicient to prevent vaporization thereof, discharging said heated oil before the cracking reaction reaches the condition where free carbon would be formed therein, into a zone of lower pressure containing a separate mass of cooler hydrocarbon oil, and checking the cracking reaction in said zone of lower presture before it reaches the condition where free carbon would be formed therein, in such a degree as to prevent the formation of free carbon in said zone by the simultaneous regulated introduction of a cooling agent into said zone.

3. A process for the conversion of hydrocarbon oils, which consists in heating a mass of relatively heavy hydrocarbon oil to a cracking temperature under a pressure suflicient to prevent vaporization thereof, discharging said heated oil before the cracking reaction reaches the condition where free car bon would be formed therein into a zone of lower pressure containing a separate mass of cooler hydrocarbon oil and checking the cracking reaction in said zone of lower prestroducing said'heated oil before the cracking v sure before it reaches the condition where free carbon would be formed therein, in such a degree as to prevent the formation of free carbon in said zone by the simultaneous regulated introduction of a cooler hydrocarbon oil into said zone.

4. A process for the conversion of hydrocarbon oils which consists of heating a mass of relatively heavy hydrocarbon oil to a cracking temperature under a pressure sufiicient to prevent vaporization thereof, discharging said heated oil before the cracking reaction reaches the condition where free carbon would be formed therein into a zone of lower pressure containing a separate mass of cooler hydrocarbon oil and checking the cracking reaction in said zone of lower pres sure before it reaches the condition Where free carbon would be formed therein, in such a degree as to prevent the formation of free carbon in said zone by intimately inter-mixing cooler oil drawn from said separate mass of cooler hydrocarbon oil with said heated oil in said zone-of lower pressure.

5. A process for the conversion of hydrocarbon oils, which consists in heating a mass of relatively heavy hydrocarbon oil to a cracking temperature above the boiling points of the complex chemical constituents of saidheavy oil under suflicient pressure to prevent vaporlzation of said chemical constltuents, in-

reaction reaches the condition where free carbon would be formed therein into a zone of lower pressure in such a manner as would permit vaporization and cracking of said chemical constituents, and checking the vaporization and cracking of said heated oil in said zone of lower pressure before said cracking reaction reaches the condition wherein free carbon would be formed therein, by the simultaneous regulated introduction of a cooling agent into said zone of lower pressure at the point of introduction of said heated oil.

6. A process for the conversion of hydrocarbon oils, which consists in heating a mass of relatively heavy hydrocarbon oil to a cracking temperature above the boiling points of the complex chemical constituents of said heavy oil under sufiicient pressure to prevent vaporization of said chemical constituents,introducing sa'id heated oil before the cracking reaction reaches the condition where free carbon would be formed therein into a zone of lower pressure in such a manner as would permit vaporization and cracking of said chemical constituents and checking the .vaporization and cracking in said zone of lower pressure before the condition is reached where free carbon would be formed therein, in such a degree as to prevent the formation of free carbon in said zone of lower pressure by the regulated introduction of a cooler mass of hydrocarbon oil at the point of introduction of said heated oil.

7. A process for the conversion of hydro reaction reaches the condition where freecarbon would be formed therein, into a zone of lower pressure containing a separate mass of cooler hydrocarbon oil, checking the cracking reaction in said zone of lower pressure before it reaches the condition where free carbon would be formed therein, in such a degree as to prevent the formation of free carbon in said zone of lower pressure by the simultaneous regulated interniixtureofa cooler hydrocarbon oil with said heated oil and introducing the mixture thus formed into said separate mass of cooler hydrocarbon oil, separating out the resultant vaporized and uncondensed products and subjectingthem to fractional comlensation.

8. A process for the conversion of hydrocarbon oils, which consists in heating a mass of relatively heavy hydrocarbon oil to a cracking temperature under a pressure sufficient to prevent vaporization thereof, discharging said heated oil before the cracking reaction reaches the condition where free carbon would be formed therein, into a zone of lower pressure containing a separate mass of cooler hydrocarbon oil, cln cking the cracking reaction in said zone of lower pressure before it reaches the condition where free carbon would be formed therein, in such a degree as to prevent the formation of free carbon in said zone of lower pressure by the simultaneous regulated inter-mixture of a cooler hydrocarbon oil with said heated oil and introducing the mixture thus formed into said separate mass of'cooler hydrocarbon oil.

9. A process for the conversion of hydrocarbon oils, which consists in heating a mass of relatively heavy hydrocarbon oil to a cracking temperature under a pressure sufficient to prevent vaporization thereof, discharging said heated oil before the cracking reaction reaches the condition where free carbon would be formed therein, into a zone of lower pressure containing a separate mass of coolerreaches the condition where free carbonwould be formed therein, in such a degree as to prevent the formation of free carbon in said zone of lower pressure by the simultaneous regulated intermixture of a portion of oil withdrawn from said separate mass of cooler hydrocarbon oil with said heated oil, separating out the resultant vaporized and uncondensed products, subjecting said vaporized and uncondensed products to fractional condensation, and returning a portion of the condensates of said fractional condensation to said mass of cooler oil.

a '10. A process for the conversion of hydrocarbon oils, which consists in heating a mass of relatively heavy hydrocarbon oil to a crack-' ing temperature under a pressure suflicient to prevent vaporization thereof, discharging said heated oil before .the crackin reaction reaches the condition where free car on would be formed therein into a zone of lower pressure, containing a separate mass of cooler said separate mass of cooler oil in order to maintain said mass in the desired condition of solution and at a temperature such as will prevent the production of free carbon therein.

11. A process for the conversion of hydrocarbon oils, which consists in heating a mass of relatively heavy hydrocarbon oil to a cracking temperature under a pressure suficient to prevent vaporization thereof, discharging said heated oil into a zone of lower pressure before the cracking reaction reaches the condition where free carbon would be formed therein, intermixing said heated oil with a mass of cooler hydrocarbon oil within said zone in order to check said cracking reaction in such a degree as toprevent the formation of free carbon therein, separating out the vaporized and uncondensed products of such intermixture, subjecting said vaporized and uncondensed products to fractional condensation, returning a regulated portion of the condensates of said fractional condensation to I said mass of cooler oil, mixing a separate portion of said fractional condensates and a separate mass of fresh 011 ,return1ng the IH1X- products. 7

12. A process for the conversion of hydrocarbon oils, which consists in heating a mass 7 of relatively heavy hydrocarbon oil to a cracking temperature under a pressure sufficient to prevent vaporization thereof, discharging said heated oil before the crackin reaction reaches the condition where free car on would be formed therein into a zone of lower pressure having a separate mass of cooler hydro; carbon oil therein, checking the cracking reaction in said zone of lower pressure before it reaches the condition where free carbon would be formed therein, in such a de ee as to prevent the formation of free car on in said zone of lower pressure by the regulated intermixture of a cooler hydrocarbon oil with I said heated oil,introducing the resultant mixture of oils into said separate mass of cooler oil, separating out the vaporized and uncondensed products of such intermixture and maintaining said separate mass of cooler oil at such a temperature as will revent the for; mation of free carbon therein. 13. A process for the conversion of hydrocarbon oils which consists in heating a mass of hydrocarbon oil to a cracking temperature in such a manner as to cause a cracking reaction therein under an externally applied pressure sufficient to prevent vaporization thereof, directly discharging said heated oil into an enlarged zone of lower pressure before the cracking reaction reaches the condition where free carbon would be formed therein, and simultaneously therewith checking said cracking reaction in said enlarged zone of lower pressure by a reduction in temperature of said heated oil in such a degree as to revent free carbon formation in said zone 0 lower pressure. v

Signed at Chicago, Illinois, this 18th day of November, 1924.

JOSEPH F. DUNN'ELLY.

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