US1805686A - Process for treating petroleum hydrocarbons in the vapor phase - Google Patents

Description

May 19, 1931. R. cRoss v PROCESS FOR TREATING PETROLEUM HYDROCARBONS I'N THE VAPOR I KHASE Filed oct. 16,1925

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KANSAS CITY, MISSOURI, SSIGNOB T0 CROSS DEVELOPMENT 0l' WILMDTGTON, DELAWARE, A CORPORATION 0F DELAWARE raocass roa'ramrme ummm maconnerie nr rma varon russa Application mea ocmw 1e, 192e. serial mi. 142,016.

This invention relates to improvements in a process for treating petroleum hydrocar-I bons in the vapor phase, and refers more particularly to the treatment of hydrocarbon g'vpors with alkaline earth metals, such as s ium, potassium, calcium, magnesium, strontium, barium and lithium.

This application is in part a continuation of an application Serial No. 119,171, -led o June 28,1926.

Among the objects of the invention are to provide a process or method in which oil is subjected to cracking conditions of temperature and pressure inl a cracking process and ,5 the cracked products passed to a vaporizing stage wherein the lighter fractions are distilled from the-highly heated oil, these distilled fractions being subjected to a dephleg mating action. and passing thence to a treating stage where the are brought in intimate contact in counterow relation with an alkaline earth or alkali metal heated to a temperature above its melting point so that the treating material exists in a molten or liquid B state; to provide a process in'w 'ch the treating material is continuously circulated 1 n counter-flow relation with the vapors, additional treating'material being added as `the liquid becomes spent or exhausted; to provide a process in` which polymerized products are withdrawn from the treating stage 'and re-v turned to be redistilled in a hotter zone ofthe system, while certain of the reaction.V products are diverted from the' system, and 1n general to provide a process and apparatus hereina'flter desclribcd. di ti' e e '1sa agrammacsie elevat'rlildviewgolean aparatus in whichthe process maybepractice j Referring tothe drawin at 1 1s shown a 1 furnace consistin 'of a com ustion compartvment 2 and a tu compartment 3. .[n the `latter compartment is positioned' aheating coil 4 having a supply line 5 and a discharge line 6 communicating with a reaction chamber 7.A The reaction chamber is preferabl top of the dftox prevent loss of heat by radiation. A. transfer line 8, in which is interposed a reducing valve 9 connects the chamber with an evaporator 10, The evaporator has anoverhead vapor line 11 communicating with the lower portion of a dephlegmating tower 12 which is preferably of the bubble t pe.- A draw 0E line 13 is connected into the ottom of the evaporator and is controlled by a valve'14 controlled by a liquid level regulatinl device, diagrammatically shown at 15. A imilar mechanism controls the valve 16 interposed inthe draw ofi pipe 17 connected into the bottom of the dephlegmating tower 12. `The discharge line 13 terminates in a cooling coil positioned in the cooler 18, thedischarge from the cooler being controlled byra valve 19. The discharge from the rell tion with the tank 2O a pi e 21 leading from the tank to the suction si e of the pump 22 whose discharge line 23 has connection-with the supply line 5 to the heating coil.

' The vapor line 24 connecting the top serves to discharge the vapors passin oil from the dephlegmator into t e lower portion of the treating tower 25. This treating Xing tower has connectower is-also of the bubble type construction in which a series of pools are maintained by overflow standpipes and capped vapor risers which serve to cause the vapors passing upwardly through the tower to percolate through the pools of liquid. The top of the treating tower has a vapor connection 26 with the coil 27 inthe condenser 28, the discharge end of the coil 27 terminating in a line 29 connected into the gas separator ,30. 4This gas separator has a gas line 31 controlled by a valve 32 and a liquld draw of! line 33 regulated by a valve 34.

For the circulation of the treating material a draw oi line 35 isconnected into the bottom ofthe treating towerv 25. Through this lineand connections the treating material is directed to' atank 35* from'which the treating material is withdrawn by the pump 36 and returned to the tower through the pipe 37. A secondary line 38,' controlled by a valve 39, connected into the ipe 35z serves as a meanslfor supply'inv treatmgmaterial to the system as e material circul through the tower becomes exhausted or standpipe 43 in the tbottom of the treatingA tower, has a continuation in the draw oil line 44, which is connected to thev spent.

, There is also arranged on the side of the tower and adjacent the lower liquid pool,"""a

sight, or liquid gauge glass 40, iny order that the level of the liquid can be seen. f

A draw off line 41, controlled by a valve 42, is' connected into the bottom of a treating tower in the form of a standpipe 42a. This standpipe arrangement is for the purpose of drawm od reaction products from the surface of the treatinr material. A second form of a suction side of the pump 45. By means of this pump polymers withdrawn from the top of the liquid body in the treating tower are pumped through the pipe 46 and discharged into .the bottom of the evaporator 10, where .they are redistilled and the unvaporized materlal drawn ott with the heavy bottom through the line 13.

In operation the oil is supplied from any convenlent source through the pipe 47 and pump 48, andpass through the lin'e 49 and coil 50 positioned in the top ofthe tower 12, where it is subjected to the heat of the vapors in the tower. After being preheated in this manner it is directed to the line 51, which communicates with the suppl, line 5, and is circulated thence through the eating coils of the furnace 1. In the furnace it is raised to a cracking temperature and in this condition is passed to the reaction chamber where the cracking reaction instituted in the coils is completed, the temperature and pressure maintained upon the coils and reaction chamber will vary according to the oil undergoing treatment.

from 650 to 1000 F., and vpressures from are usual. The oil on being discharged from the reaction chamber is introduced at reduced preure into the evaporator 10. The reduction of pressure, together with the contained heat of the oil, distills olf the lighter fractions which pass overhead through the line 11 to the dephlegmating tower 12. The bottom from the evaporator 1s diverted from the system after being cooled in the cooler 18.

In the dephl'egmatingr ltower the vapors are subjected to a relu'xing action, the unvaporized material automatically withdrawn and recycled for retreatment by means of the pump 22, while the vapors discharged from the top of the bubble tower are 'introduced into the lower portion of the treating tower. In the treating tower the'vapors rise and are perolated through a. plurality of pools of treating liquid, therebybeing brought in inrial.

Normally temperatures ranging to maintain it in liquid state through th pipe 38.

A by-pass line 55, between the vapor pipe: 24 and 26, serves to cut out the tower from the system when desirable, the vapors then passing directly from the tower 12 to the condenser 28. Vapors 53, 54 and 54 govern the use of the by-pass line 55.

Connected into the upper portion of the tower 12 is a pipe 56 controlled by a valve 57, bymeans of which materials-may be added to the refluXing tower. In bringing the system on stream, normally the treating towr is cut out until the apparatus has been brought to temperature and during this period a considerable quantity of distillate will have been produced. This distillate is returned and introduced into the refluxing stage, through the pipe 56, when the treating tower 25 is cut in Order that the products will all be uniform in character.

Returning to the method of treating, when suihcient treating materialv has been introduced to the system the valve 39 in the line 38 is closed. rlhe material is directed through pipe 61 to the tank 35El which is insulated and heated by a steam coil 62.

As suggested, the heated liquid treatlng material is picked up by the pump 36 and forced through the line 37 into the treating tower at a point suilciently high thereon to permit the accumulation of the material on a plurality of trays' but at the same time leaving a fractionating zone beyond the treating stage. It may be desirable to have the treating stage and final fractionating stage in separate towers.

In the event it is necessary to isolate the tank 35@a `from the system for cleaning purposes or otherwise, the valve inthe line 61 and the valve63 inthe line between the tank 35.a andv the pump 36v are closed and the treating material diverted directly from' the draw od line 35 through the pipe 59 to the suction ofthe pump 36. 1

The tank 35* is equipped with a draw o` line 64, controlled by a valve 65. The equip-ll ment including the trap in the tower 25,A through which the treatmg material is circulated, is heavily insulated to prevent loss of 1 ousl circulated to and fromthe system.

e temperature of the va ors in the treating toweris suicient to malntain the treating material in a liquid condition. lIf this is not the case, heat may be added to the botl:

tom of the tower to keep the alkaline earth metal in liquid form, or by heat supplied to the tank 35.

In the description of the process the use of sodium as a treating `materlal has been. used i2 mg' material may be introduced, or continul larly the acid and caustic 40 is used for determining the liquid level in the bottom of the ltower. From time to time the .polymers or reaction products may be withdrawn through the line 41 and diverted from the system or recycled to the evaporator for redistillation.

The treated vapor passing oi romthe top of the tower is subjected to a final condensing action and collected in the gas separator from which the treated liquid is withdrawn through the valve 34, and the gaseous material through the valve 32.

' In vactual practice hydrocarbon vapors treated with metallic sodium, or other alkaline earth metals have been effectively puritied to produce a water white sweet hydrocarbon distillate. rFhe alkaline carths, particularly sodium, have an alinity for the sulphur compounds in the oil, and effectively remove these compounds with a very low percentage of loss of the volume of the treated oil.

Actual tests in which cracked distillates -from the Mid-Continent and Californian fields, in which the oils were vaporized andthe vapors passed throughA successive pools of liquid sodium, produced a clear water white product which did not discolor on standing and passed both the doctor and copper corrosion tests. p

As to sulphur removal, the alkali metals, such as potassium and sodium, are very active, though magnesium and calcium are more effective quantitatively. In come instances it is desirable to use Ythe combination of the metals in place of a single metal, the peculiar characteristics of the oils being treated more or less determining the metals most advantageoiisly used as an eiective purifier.

As suggested, the losses with this type of treatment are much less from the usual methods of reining, particutreatment which is com'mon to most refiners.

While the process of treating has been ex- --plained in connection with a high pressure,

cracking process, it is as eective for the treatment ot any with sulphur compounds, whether a product of straight distillation, cracking or rerunning equipment.

The lines through which the tre ating material is circulated are preferably heavily insulated.

I claim as my invention: 1. A method of purifying petroleum hydrocarbons, comprising the steps ot subject- -ing the oil to cracking conditions of teinperature and pressure, dephlegmating the vapors evolved and bringing them in intimate contact with metallic sodium heated suili- .ously circulating th an those resulting distillate contaminated ciently to exist in the liquid phase, continu- A the treating liquid in counterlow relation with the oil vapor, diverting separated polymers and reaction roducts and supply additional unused treating metal with t e exhaustion of the treating stream to eiect continuous operation.

2. A process, such claim l, in which selected portions of the polymerized products are recycled for redistillation in the system.

3. A process, such as that described in claim 1, in which the oil vapors treated by counter-110W contact with metallic sodium are at a temperature sutliciently high to maintain the' treatin material in molten or liquid form during tIieir contact therewith. v

4. A continuous method of purifying petroleum hydrocarbons comprising the steps of vaporizing the hydrocarbons and bringing the evolved vapors into intimate contact with metallic sodium heated suiiiciently to exist in the liquid phase, continuously circulating the treating liquid in with the oil vapor, diverting separated polymers and'reaction products and supplying additional unused treating metal.

5. A continuous method of purifying petroleum hydrocarbons comprising the steps of vaporizing an oil and bringing the vapors into intimate contact with metallic sodium heated suiiciently to exist in the liquid phase, continuousl circulating the treating liquid in counte ow relation with the oil vapor,

diverting separated polymers and reaction counteriow relation as that described in v y iis

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