US1798338A - Apparatus for treating hydrocarbon oils - Google Patents

Description

March 1931. E. E. STEWART APPARATUS FOR TREATING HYDROCARBON QILS Filed Nov. 2 Sheets-Sheet l vN RN A TTORNE Y March 31, 1931. E. E. STEWART 1,798,338

APPARATUS FOR TREATING HYDROCARBON OILS iililinm w im WM W P HM HH INVENTOR ATTORNEY Pa tented Mar. 31, 1931 UNITED STATES PATENT o1=1=1cu EDWARD E. STEWART, F WIGHITA. FALLS, TEXAS v APPARATUS FOR TREATING HYDROOABBON CHIS Application filed Iovember s, 1926. seriarno. 146,671.

My invention' relates to apparatus for treating hydrocarbon oils for the purpose of separating and extracting the lighter from the heavier hydrocarbons by efi'ecting sepa- 5 ration of natural gasolines without injury to their texture, and/or for recovering additional gasoline by breaking down or cracking of the heavier hydrocarbons,the principal object of the invention being to provide an apparatus ofthischaracter wherein oils of diflerent gravity and gasoline content may be treated according to, their nature treatment and the amount of gasoline which it is desired to recover. f

More specifically, the apparatus comprises a recirculation circuit wherein the fluid is reheated, recirculated, cooled at atmospheric pressure and reheated under pressure, the

apparatus further providing for elimination of water vapors at substantlally atmospheric pressure, thereby minimizing possibility of explosions in the still, by excluding such vapors from the cracking zone.

It is an established fact that light gravity liquids, such as kerosene, light distillates and gasoline, contain more hydrogen than the heavier oils. It is also a well known fact that when certain suflicient hydrogen is present in the cracking chamber that less coke is formed, and when charging stock that has been cracked is used and when the hydrogen is deficient an'excess amount of coke is deposited. It is an object of my invention to provide an apparatus wherein the objectionable coking efiectsmay be obviated by providing for a suitable amount of hydrogen in rtion' to the other components.

Other advantages of the apparatus will be disclosed the following description of the construction and operation of the mechanical elements of which the apparatus is composed.

In accomplishing the above and other objects of the invention I have provided im.

proved details of structure the preferred I forms of which are illustrated in the accompanying drawings, wherein- Fig. 1 is a diagrammatic view of an oil refining and treating apparatus embodying my invention, some of the parts being broken away for better illustration.

Fig. 2 is an enlarged, longitudinal, sectional view of the bubble tower, wherein the initial separation of vapors is efiected.

Fig. 3 is an enlarged vertical section of the primary separator tower.

Fig. 4 is an enlarged vertical section of a part of one of the bubble plates in the bubble and separator towers. v

Fig. 5 is an enlarged detail perspective view of part of one of the elements of the bubble plate, a part of the hood being broken away Referring more in detail to the drawings:

1 designates an ordinary storage tank constituting a source of supply ofnil to be treated. Leading from the tank} is a line 2 whereby oil is drawn from the supply by a pump 3 and delivered under pressure into a charging still 4. The oil is heated in'the still 4 toa temperature of about 500 degrees F. and forced through a line 5 and branch 6 into the upper portion of a vaporizer or blending zone illustrated as a bubble tower 7 where it is delivered downwardly as a shower through a nozzle 8. The branch 6 carries a valve 9 for a purpose presently described. 7

When the apparatus is in operation and the vaporizer bemg supplied. from the cracking still, as presently escribed, cracked va pors released in the vaporizer rise through the shower of liquid and, absorbing the lighter elements of the oil along with the water vapors, pass ofi from the top through a vapor line 10 to the primary separator tower 11, entering near the bottom of the tower. When the apparatus is in operation, cracked vapors enter the bottom and straight run vapors and liquid enter at the top of the vaporizer, form- 96 ing a counter current of va rs and liquid, the cracked vapors t ugh a li uid shower, a spreading element and bu ble plates, efiecting absorption or co bug at the g ter with the h avier hydroca o 1 so that a large portion of the non-condensible vapors which are ordinarily lost are absorbed and carried over with the recovered vapors.

After passing through tower 11 the lighter vapors and non-condensible gases pass off through a vapor line 12, leading from the top of tower 11 to the bottom of a fractionating tower 13, the vapors passing through the fractionating tower being drawn off through a vapor line 14 into the condenser 15 and eventually into tank 16.

'hile the lighter components of the oil are passing to the condenser as described, heavier components collect as liquid in the bottom of the vaporizer and primary separator towers, the liquid from the vaporizer passing to the bottom of the separator through a back trap line 17, level of the liquid in the separator being normally as indicated in the drawings.

lVhen the apparatus is employed for cracking, liquid is drawn from the bottom of the primary separator tower through a suction line 18, preferably by means of a hot oil pump 19, and forced through the line 20 to a second hot oil pump 21, which forces the oil through a cracking still 22, wherein the oil is heated to a temperature of approximately 890 degrees F. and wherein a pressure of approximately 250 to 300 pounds is maintained. The force from the pump 21 carries the oil through the still and out through a transfer line 23 and a depending terminal 24 into the bottom of a cracking tower 25, the terminal 24 being provided with a hand valve 27. The tower 25 is provided with a number of petcocks 25 spaced vertically for the purpose of determining levels of contents of the tower. Oil entering the first cracking tower as liquid rises through the tower to an outlet line 28 at or near the top of the tower, through which the liquid is conducted to near the top of a second high pressure cracking tower 29, also provided withpet cocks 29' as and for the purpose specified in connection with the first cracking tower.

The oil passes through the second cracking tower 29in the form of vapor to a pressure relief line 30, openingto the tower near its lower end, through which the vapors are conducted to near the bottom of a secondary separator tower 31. The line 30 carries a hand valve 32. An emergency connection between the second cracking tower and the secondary separator tower is provided in the line 33, which leaves the tower 29 and enters the tower 31 at elevations above the line 30, the emergency line being also provided with a hand valve 34. The vapors entering thesecondary separator tower expand, releasing the pressure in the circuit, the cracked components passing off from the top of the secondary separator through a vapor line 35 into the lower portion of the vaporizer 7, through which they rise, coming in contact with the initial charging vapors and oils or water vapors, as heretofore described. The heavier components (fuel oil) are drawn off from the bottom of the secondary separator tower through a tar line 36 and passed through a cooling coil 37 into a storage tank 38.

Should excessive pressure be built up in the system, initial relief is afforded through a safety valve 39 in a line 40, leading from the top of the liquid cracking tower 25 to the bottom of the vaporizer, this valve being set for operation at approximately 25 pounds above the normal system pressure. A secondary relief is afforded through a valve 41 in a line 41', leading from the top of the vapor cracking tower to near the bottom of the vaporizer, this second relief valve being referably set at approximately 50 pounds a ove the normal pressure. Consequently, should the relatively small line 30 leading from the vapor or final cracking tower to the secondary separator be insuflicient to carry off the content of the system with sufiicient rapidity and excessive pressure he built up, the relief means which I have provided will operate and prevent damage to the apparatus or interruption of the treating process.

The initial or liquid cracking tower may be relieved at any time through a line 42, leading to the cooling coil 37. The line 42 communicates with the tower through a line 43 leading from the bottom of the tower and provided with a hand valve'44: through a line 45 leading from the sideof the tower, slightly above the bottom and provided with a hand valve 46 or through a line 47, leading to a higher elevation in the tower and provided with a hand valve 48.

While treatment of oil with my apparatus reduces accumulation of coke to a minimum, there is, nevertheless, some accumulationv in the cracking towers and it is for this reason that I provide for drawing off of the oil from the tower at different elevations, the lower outlet being employed when there is a minimum accumulation in the tower and the upper outlets according to the depth of the coke. The second or vapor cracking tower may be drained into the line 42 through a branch 50, provided with a hand valve 51. The expansion tower 13 may be drained through a line 52 and cooling coil 53 into a storage tank 54.

Should it be desirable to drain the still. as in the event of burning out a tube, the relief may be effected through a line 55, connecting the line leading from the pump 21 to the still with the line 42 leading to the cooling coil 37. The line 55 is provided with a hand valve 56, which is normally closed but when opened, will permit flow of liquid under the still pressure back through the cooling coil to rapidly relieve the still of the fluid and its pressure, the cooling coil reducing the temperature of the liquid so that by the time the latter reaches the storage tank, it is below the flashing point,

. system through a line 57 into the top of the separator 11. The straight run gasoline vapors are then carried ofi through the line 12 to the condenser as originally described, the heavier components collecting as liquid in the bottom of the separator and afterwards being drawn off through the charging still for cracking.

By a difierent mode of operation of the ap paratus I separate the straight run and cracked vapors by directing the cracked vapors into a separate condenser 58 connected with the line through a branch 59 having a hand valve 60. For the operation of separately collecting the straight run and cracked gasoline, the valve 9 in line 6 and a valve 61 in line 10 are closed. and the valve 62 in line 57 and valve 60 in line 59 are opened. hen

' all of the gasoline is to be collected together,

the valve 62 in line 57 and the valve 60 in line 59 are closed, and valves 9 and 61 are opened to properly direct the flow.

It is desirable to maintain a proper volume of circulating fluid in the system at all times during operation of the apparatus. Should the accumulation in the separator 11 fall below a desirable level, fresh crude oilmay be supplied from a tank 63 connected with the pump 19 through a pipe :20 leading to pump :21 through a branch 6-1. The branch6l is normally closed by the ordinary tank valve not shown).

As a modification of the mode of operation heretofore described, I pr vide additional elimination of coke bypassing the crude oil through thecharging still at a higher temperature and pressure, such as 800 degrees F. and 100 pounds pressure, thereby elmnnatmg all heavy fuel oils. cokes and tars, passing only gas oils and wax distillates to the extreme cracking zone. Under this mode "of operation the hot liquid under high pressure is passed initially to the secondary separator tower 31 through a line 65, provided with an automatic control valve 66 .set to hold the desired pressurein the still, the valves 9 and 6:2 in the line 5 and branch 57 being, closed when the system is so operated. The liquid passing to the secondary separator tower separates into vapor and heavy liqu d. the vapors constituting approximately of the whole and passing out through pipe 35 into the vaporizer, the fuel oil from initial charging stock being drawn off from the secondary separator and fuel oil from the cranking zone being drawn off through the bottom of the secondary separator and cooling coil into the tank 38. The vapors passing into the vaporizer are partially condensed, the lighter components passing on to the separator 11 where further condensation takes place, the gasoline vapors eventually reaching the condenser, and liquid condensed in the separator 11 and in the vaporizer accumulating in the bottom of the separator and i being pumped through the cracking still in accordance with the operation first described. When the apparatus is to be employed only for skimming or re-running of cracked distillates as when the cracking still is under repair or shut down for cleaning out, the hand valve 67 in the line 35 leading from the secondary condenser to the vaporizer is closed and liquid from the charging tower delivered through the shower into the vaporizer, the vapors passing off to condensation and the heavier components back trapping in the bottom of the separator tower 11 and being drawn off through a back trap line 68 through a cooling coil 69 into a storage tank T0.

One advantage gained with my apparatus is that the non-condensible gases passing through the shower of charging stock are abwith sorbed in the latter and recovered alon the condensible vapors, thereby saving a great proportion of this useful component which would be lost if allowed to pass freely from the tower.

It is further apparent that with my apparatus, I effect the cracking in both liquid and vapor phases at different stages in the run, the liquid phase being substantially confined to the first cracking tower and the vaporphase to the second tower.

I have not attempted to describe every detail of structure embodied in the apparatus, such as gauges and the like, as this is ordinary equipment.

As a preferred construction I provide a spreader bed 71 in the vaporizer below the shower nozzle 8, which may be supplied and emptied through a manhole 72, and provide a series of bubble plates 73 above the nozzle, each comprising upwardly directed necks 7 4 and heads 7 5 seated on the plates about the necks and having toothed lower edges 7 6 through which the vapors may pass to relief at the top of the tower.

While I have, during the description of the apparatus, mentioned specific temperatures and pressures, I do not wish to be understood as limiting myself to them as any suitable temperatures and pressures may be employed.

It is apparent, therefore, that I have pro- Y vided an apparatus whereby various treatments of oils for the recovery of gasoline may be effected, the selection of modes of operation being optional, and with which the treatments described may be effected with a material saving in labor and fuel costs.

What I claim and desire to secure by Letters Patent is 1. In apparatus of the character described, a charging still, a vaporizer, a line from the charging still having an inlet to the vaporizer adjacent the upper end thereof, a cracking still, a cracking unit in receiving relation to the cracking still, a secondary separator in receiving relation to the cracking unit, means for withdrawing condensates from the secondary separator, means for delivering vapor from the secondary separator to the vaporizer below said inlet from the charging still, a primary separator having a liquid outlet near its lower end, a vapor line leading from the vaporizer above said inlet and delivering to the primary separator, a condenser in receiving relation to the primary separator, means for delivering liquid from the vaporizer to the lower end portion of the primary separator, and means connected with said outlet for delivering liquid from the primary separator to the cracking still.

2. In apparatus of the character described, a. charging still, a vaporizer, a supply line from the charging still having an inlet to the vaporizer adjacent the upper end thereof, a cracking still, a cracking unit in receiving relation to the cracking still, a secondary separator in receiving relation to the cracking unit, means for withdrawing condesates from the secondary separator, means for delivering vapor from the secondary separator to the vaporizer below said inlet from the charging still, a primary separator having an outlet near its lower end and adapted to contain liquid at a level for sealing the outlet and an intake from the vaporizer above said liquid level, a vapor line leading from the vaporizer above said inlet and delivering to the primary separator above the level of liquid therein, a condenser in receiving relation to the primary separator, means for delivering liquid from the vaporizer to the primary separator below said intake, and means connected with said outlet for delivering liquid from the primary separator to the cracking still.

3. In apparatus of the character described, a charging still, a vaporizer having an intake in its upper portion, a line leading from the charging still to said intake, a cracking still, a hlgh pressure primary cracking tower for liquid phase cracking in receiving relation to the cracking still, a secondary cracking tower for vapor phase cracking in receiving relation 'to the primary cracking tower and having a liquid outlet, a secondary separator, means for withdrawing condensates from the secondary separator, a line leading from the secondary cracking tower to the secondary separator, means for delivering vapors from the secondary separator to the vaporizer below the intake from the charging still, a primary separator having a vapor inlet in spaced relation with the bottom thereof to provide for a liquid level therein and having a liquid outlet and a valved'drain port at its lower end, a vapor line leading from the vaporizer above said intake and adapted to deliver vapor to the vapor inlet of the primary separator, a liquid line for gravity flow of li uid from the vaporizer to the primary sepa ator below said vapor inlet thereof, a line from said liquid outlet of the primary separator to the cracking still, and a condenser in receiving relation to the primary separator.

4. In hydrocarbon treating apparatus of the character described, a cracking still, a high pressure cracking unit in receiving relation to the cracking still, a secondary separator comprising a zone of low pressure in receiving relation to said cracking unit having an outlet for heavy hydrocarbons condensed therein, a vaporizer in receiving relation to the secondary separator, a primary separator adapted to contain liquid at approximately a predetermined level,'a condenser in receiving relation tothe primary separator, means for delivering intermediate hydrocarbons condensed in said vaporizer to the primary separator to maintain the levelof liquid therein, means for conducting vapor from the vaporizer and the primary separator, means fordelivering liquid from the primary separator to the cracking still, and means connected with said outlet for removing said heavy condensates from the secondary separator.

5. In hydrocarbon treating apparatus of the character described, a charging still, a cracking still. a vaporizer, a primary separator, a liquid line leading from the vaporizer to the primary separator, means for delivering liquid from the primary separator to the cracking still, a cracking unit in receiving relation to the cracking still,-a secondary separator in receiving relation to the cracking unit and having a liquid outlet toward storage, a vapor line leading from the secondary separator to the vaporizer, a line for conducting streams from the charging still to the upper portion of the vaporizer whereby heated charging stock may be fed into the vaporizer to mingle with condensates of vapors from the secondary separator for flow to the primary separator to be delivered to the cracking still, and means for restricting the delivery means to recirculation of condensates comprising means for diverting the V 6. In apparatus of the character described, a circuit, comprising a cracking still, a cracking unit in receiving relation to the cracking still, a secondary separator, a vapor line leading from the cracking unit tothe secondary separator, a vaporizer, a vapor line leading from the secondary separator to the vapor izer a primary separator, a liquid line for delivering condensates by gravity from the vaporizer to the primary separator, a vapor line leading from the upper portion of the vaporizer to the primary separator, and means for passing said condensates from the primary separator through the cracking still to the secondary separator, the primary separator having a vapor outlet, means for supplying charging stock in vaporous form comprising a charging still and a line leading from the charging still to the secondary sepa-' rator, and means for conducting unvapo'rized portions of the charging stock from the secondary separator.

7. In apparatus of the character described, a circuit, comprising a cracking still, a cracking unit in receiving relation to the cracking still, a secondary separator, a vapor line leading from the cracking unit to the secondary separator, a vaporizer, a primary separator, a liquid line for delivering condensates by gravity from the vaporizer to the primary separator, a vapor line leading from the upper portion of the vaporizer to the primary separator, and means for passingsaid con densates from the primary separator'through the cracking still to the secondary separator, a vapor line leading from the secondary separator to the vaporizer, a vapor outlet in the primary. separator, means for supplying charging stock to the circuit comprising a charging still, a line leading from the charging still and having a branch to the upper portion of the vaporizer and a branchto the secondary separator, and means for selectively introducing liquid or vaporous charging stock to the circuit including manually operable valves in the branches and means for Withdrawing unvaporized charging stock from the secondary separator when the vaporizer branch valve is closed to prevent flow of unseparated charging stock to the vaporizer and the other branch valve is open to admit charging stock to the secondary separator.

In testimony whereof I afiix my signature.

EDWARD E. STEWART.

Images