US2440784A - Process for regenerating a solid desiccating agent - Google Patents

Description

WW ,j #WW WU L-V-l-ff humm May 4, 1948.` w. E. PERDEW 2,440,784

4 PROCESS FOR REGENERATING A SOLID DESICCATING AGENT Filed Jan. les, 1943v Wn-000 Wamv vision of aprooessin Patented May 4, 1948 PRQCES; S .YFORLREGENER fDESIQCATING i vVlillia1.1 .E- llerdem Keohi gTow-nshiv, Sedgwick `County, Kans., assjgnor to Globe/Oil &-Rening ompany, "Wichita, tKans., acer-poration of -AnPlieationI-lanuaty 16, 1943, Serial No- 472,574

This invention relatestoapiooess iorreeenereting ardesioeatine agent. andmorenertionlarly to a proeessfor degeneratie a.solid,desieoetirie agent of the water adsorption typense for 'the removal ofdissolved :water from .low boiling `hydrocarbon oils- I The process oftliis inventionis partieularly osefill for .regenerating a, desieeatine asentthat Y is `used 4-f0.1 the .remotal of f small quantities: of

dissolved ,water Atroni hydrocarbon oils nrior to Ythe time thatthe hydrooatbonoilsare passed into transportation pipe lines. Thesmall .olla .titles of water normally .founddissolved in certain .hy-

drocarbon oils, such ,as lgasoline, kerosene,

straight-run distillatel tracked distillate., toto., may have atendeitey toooridense within atrans- 4portation pine lil-.1ebeoalise..ofthe -relativelyzlow temperatures thatmay Joe ren.eolliitered therein. l This, oondensed .water `leasa i tendency to -eaiise i eorrosion in `pinelimes- -ltiis well l known thattlie dissolved water eootentfof .tee ,nydtooarloon .oil

een be reducedibylpassiriethe,oil overasolid adsorbent 11n-er1 oil eso ttreated water cdroplets Will-riot :have a tendeaoyto e dense -olpreoipi- `tate in the lpipeline The nated therein. llt isan oleieet A@athis invention lto provide aI-meansofor.-reaotvating, revit/if ing i or i regenerating La solid.fzilesiccating agent A,Wflgiich `may be usedior ,.reduoins thedissolved water content of :hydroearloon .oils .prior l.to the :time that they .are Ipassed .into l:.trans,portation n.pipe lines. I i t VIt is a furtherobjectof` this-inventiontoeprovide .a proces for reeeneeatirtathe sollddesioeatingfagent-Vfundensueh conditionsV that ,atmos- -;pher io oxygeniortother-eesfislnot introdueeddi- `reotly'into thenipe line A ifurther objectof-` hishinvention is =tllecinjoagent Vis thoroughly washeddiinathe ytion step to removei-anyiresidues-that-,may have been deposited utherein -by `the passage fof ythe hydrocarbon Y oil tbeing -Adesiooated therethrough- 'A furtherandfadditiorialobjectof this invention is 4-to l provide etsolid. desiooating agent ref generation prooesstwherein the agent is ;dr.ed with a hot inertfsasfwltioh is r.s ,-11lost'.1r1tially capable of reacting with the desiccating agent i .l e of -corrosion in theloipe line maytthereby e` ubstantially .det creased or the oorrlosion may y Joe ...entirely elimi- 2 or of -polymerizing or formi-ng undesirable liquid or solid productswhen it is contactedwith asolid desiceating agent.`

Further and additional objects will appear from -ths specication, the accompanying drawing and-the appended claims.

In accordance With one embodiment of this invention, vthesolid desiccatingagent used inthe rem-oval of dissolved `Water from hydrocarbon oils may be-regeneratedbyfirst washing the desiccat- Aing agent with a lowboiling hydrocarbon liquid, `pass-ing `a stream lof `gasinto contact with the Washed desiccating agent at an elevated temperature whereby to remove Water therefrom in the '1&5l

4 iccating agent `With `a low boiling lnonaqueous form of a vapor, andtbereafter flooding said desliquidto prevent the Acontact `of gases therewith prior to the time thattthe desiccating agent Vis 4reused-Afortliie removal of `dissolved -Water from the hydrocarbon oil being processed. If desired, the desiccating agentmay be disposed in suitably enlarged chambers, and anumberof these cham- -bers maybe arranged in series -sothat a desired degree of dissolved AWater'rernoval from-the oil being treated may be effected. In -accordance with the present invention, one ofi--the-chambers czontaining the desiccating agent `may be cut iout of thel series and subjected to the regeneration ,process while `the hydrocarbon oil being treated is passed through the remainder of thechambers i in series. ,maybe used for Washing'the desiccat-ing agent in Any `low boiling hydrocarbon liquid 4thecl'iarnioerpriorto the actual regeneratingstep.

j itoweveiq, any other loyv boiling hydrocarbon oil AVstraight-runnaphtha having a boiling point between 500 and 400 `F. may suitablybe used.

maybe nsedjforthewashing step, itbeingjpref- Merablhetliat all the constituents thereof be evapotable so thata residue will not b eleft on the desiccating agent during the regeneration step.

vI {l1ein,ert gas used for expelling the nadsorbed Water fromthe desieeating agent may suitably loe naturellgas- .Howevery other gases, suoh as eombiistion eases, still eases, oraekine eases and Vltlnetlile, .maybe used. Natural gas ispreferred beoeuse it cheap .and is. substantially `free from dust, sulfur dioxide, hydrogensulde, oxygen,

polymerizable Qlnic hydrocarbons, and @ther able eodstituents However, carbon dioxide or nitrogen` or other inert gas ,fzre' from the chamber 2.

undesirable products could be used with equal efficiency. In accordance with one embodiment of this invention the hot regenerating gas, after having been contacted with the solid desiccating agent, may be coooled to condense and separate the water vapors therein and reheated and recycled to the desiccating agent in order to effect further water removal. This process therefore requires only small amounts of regenerating gas which may be continually used in the process.

For a more complete understanding of this invention, reference will now be had to the accompanying drawing wherein is shown diagrammatically an apparatus for carrying out the process of this invention. Essentially the apparatus shown in the drawing comprises three chambersv 2, 4 and 6 arranged in series, each having disposed therein a solid substance, such as dried silica gel or activated alumina, capable of absorbing dissolved water from a hydrocarbon oil which may be contacted therewith. These chambers are connected in series-by suitable piping, and are further arranged so that any one of the chambers may be cut from the oil treating system for purposes of regeneration while the oil to be desiccated is passed through the remaining chambers of the series.

The oil from storage containingsubstantial amounts of dissolved water is passed from storage through the pipe 8 to the treating chambers, and the oil from which the desired amount of dissolved water has been removed after passage through the chambers is discharged from the desiccating system to the transportation pipe line I6. Gas for the regeneration or revivication of the desiccating agent is heated in a gas heater I2, and after passage through the chamber being regenerated (2, 4 or 6) passes through the gas cooler I4 in order to condense the' water vapor which separates in the Water separator I6. If desired, the entire oil desiccating system can be by-passed through the pipe I8 so that the oil from storage may be passed directly to the pipe line I6 without contacting the solid desiccating agent disposed in chambers 2, 4 and '6. As shown in the drawing, a number of pipes controlled by suitable valves are provided for cutting the charn- 4bers 2, 4 and 6 into and out of the system in the manner to be described and for effecting the desired washing and treatment of the desiccating -agent to effect the desired regeneration or revivication thereof.

In carrying out this process the oil to be desiccated may be passed from storage through pump 26, valve 22, pipe 8, pipe 24, valve 26, into The chamber 2 has disposed therein a, solid desiccating agent, preferably of the adsorption type, such as silica gel or activated alumina, for removing at least a portion of the vdissolved water normally present in the oil. The

therein, the oil passes continuously from the top vof the chamber 4 to the transportation pipe line I0 -through pipe 48, valve 42, pipes 44 and 46, valve 48, pipe 56, pump 52, pipe 54, valve 56, pipe 58, and valve 6I).

, y While the oil is being passed through the Yld icwcgriling chambers 2 and 4 as above described,`

75 naphtha contained therein flows directly into the chamber 6 has been cut out of the system by suitable valve manipulation. The oil remaining in chamber 6 is drained therefrom to a suitable sump (not shown) through a pipe 62, a Valve 64, and a pipe 66. After the oil has been withdrawn from the chamber 6, the chamber is then lled by suitable valve manipulation with a straight-run naphtha contained within storage tank 68. The naphtha flows from the storage tank 68 to the chamber 6 through pipe 10, valve 12, pipe 14, valve 16, and the pipe 62. Whilebeing emptied of oil and lled with naphtha, the chamber 6 is vented through pipe 18, valve 80, pipe 82', and pipe 66. The naphtha serves to wash out any nonvolatile hydrocarbon residue that may be present on the desiccating agent within the chamber 6. The character of the naphtha is such that it contains substantially no nonvolatile constituents so that no residue is left deposited on the solid adsorbent during the subsequent heated gas treatment. In the event that it is desired continually to pass the straight-run washing naphtha through the chamber 6 for a period of time, then the naphtha passes from the upper portion of the chamber through pipe 18, Valve 80, and pipe 82, into the sump pipe 66. After the washing of the desiccating agentin the chamber '6 by the naphtha, the excess naphtha is then drained from the chamber 6 through the pipe 62, the valve 64, and the sump pipe 66.

After washing the desiccating agent -in chamber 6 and draining of the wash naphtha through pipe 62, valve 64 and pipe 66, a stream of natural gas heated in the gas heater I2 is passed through pipe 84, valve 86 and the pipe 62 into the bottom of the chamber '6. The hot gas serves to vaporize the water adsorbed on the surface of the solid desiccating agent. The gas and water vapors pass from the chamber 6 through the pipe 18,

valve 88, and pipe 90 to the gas cooler I4 wherein the water condenses from the gas. The co-ndensed water is removed` from. the gas` in vthe water separator I6, and the gas is recycled through pipe 92, gas compressor 94, valve 96, and pipe 98 to theY gas heater I2 and reused as described above. Pipes |60 'and |02, controlled by suitable valves, may be employed for introducing and withdrawing gas from the system. Y

After the desired degree of reviviflcation or regeneration of the desiccating agent in chamber 6 has been effected, cool gas may be cycled through the chamber in order to cool the desiccating agent. This maybe accomplished by cutting the steam supply oi of the gas heater I2 and cycling the gas as above described. After the desiccating agent in the chamber 64 has been cooled somewhat, a fresh charge of straight-run naphtha from the storage tank` 68 is introduced into the chamber 6 in order further to cool the desiccating agent therein. e This charge of naphtha in chamber 6 covers or floods the solid desiccating agent and serves to prevent air from contacting the regenerated solid desiccating agent prior to the time that the chamber 6 is cut back into the desiccating system. Itis desired not to pass air over the desiccating bed because of its probable deleterious effects on the bed and oil retained therein; and it is desired also to keep all gas, including air, out of the transportation pipe line. Hence the gas remaining in chamber 6 after regeneration is completely displaced with naphtha. When the chamber 6 is to be cut back into the desiccating process, suitable valves are manipulated so that the charge of straight-run pipe line i9 with the oil that is passed through the system. This naphtha should have properties (particularly in respect to color and boiling point) which will permit of its being pumped directly into the pipe line with the hydrocarbon oil being treated without lowering the speciiications of the latter below tolerance.

When the solid desiccating agent in chamber 2 or in chamber 4 needs revivifying or regenerating, these chambers may be cut out of the system by the manipulation of suitable valves and regenerated in the same manner as described in the foregoing in connection with chamber il. When the chambers are connected in series in the manner described above, it is desirable that the first chamber into which the oil to be treated.

is owed is the one which has the highest amount of adsorbed water therein so that the desiccating agent last contacted by the oil being treated is the agent which has been most recently revivifled or regenerated.

While in the drawing three desiccatingr chambers have been shown and described, this number is of course not essential in accordnace with the teachings of this present invention. For example, any number of chambers containing desiccating agents may be used and they may be connected in series or in parallel, or partly in series and partly in parallel, as desired.

While a particular embodiment of this invention is shown above, it will be understood, of course, that the invention is not to be limited thereto, since many modifications may be made, and it is contemplated, therefore, by the appended claims, to cover any such modifications as fall within the true spirit and scope of this invention.

I claim:

1. In the art of transporting a hydrocarbon liquid through a pipe line wherein said liquid is passed through a body of a solid desiccating agent for the removal of water dissolved in said liquid prior to the introduction of said liquid into said pipe line, the process of periodically regenerating said desiccating agent which comprises discontinuing the ow of hydrocarbon liquid through said body, washing said body of desiccating agent with a low-boiling hydrocarbon wash liquid, passing a stream of a substantially noncondensible and nonoxidizing inert gas through said body at an elevated temperature whereby to remove water therefrom in the form of a. vapor, :flooding said body with a lowboiling liquid hydrocarbon to displace all of said inert gas within said body to prevent the inclusion of gas within the hydrocarbon liquid when the desiccating agent is reused, and thereafter reestablishing the flow of said hydrocarbon liquid through said body of desiccating agent.

2. In the art of transporting a hydrocarbon liquid through a pipe line wherein said liquid is passed through a body of a solid desiccating agent for the removal o@ water dissolved in said liquid prior to the introduction or said liquid into said pipe line, the process of periodically regenerating said desiccating agent which comprises discontinuing the ow of hydrocarbon liquid through said body, draining excess amounts of said liquid from said body, washing the drained body with a low boiling hydrocarbon Wash liquid, draining excess wash liquid from said body, passing a stream of a substantially noncondensible and nonoxidizing inert gas through said body at an elevated temperature whereby to remove Water therefrom in the form of a vapor, flooding said body with a low boiling hydrocarbon displacement liquid to displace all of said inert gas within said body to prevent the inclusion of gas within the hydrocarbon liquid when the desiccating agent is reused, and thereafter reestablishing the flow of said hydrocarbon liquid through said body of desiccating agent whereby said displacement liquid and said hydrocarbon liquid pass together into said pipe line.

3. In the art of transporting a hydrocarbon liquid through a pipe line wherein said liquid is passed through a body of a solid desiccating agent for the removal of water dissolved in said liquid prior to the introduction of said liquid into said pipe line, the process of periodically regenerating said desiccating agent which comprises discontinuing the flow of hydrocarbon liquid through said body, draining excess amounts of said liquid from said body, washing the drained body with a low boiling hydrocarbon wash liquid, draining excess wash liquid from said body, passing a stream of a substantially noncondensible and nonoxidizing inert gas through said body at an elevated temperature whereby to remove water therefrom in the form of a vapor, thereafter passing a cooler stream of said gas through said body to lower the temperature, then iiooding said body with a low boiling hydrocarbon displacement liquid to displace all of said inert gas within said body to prevent the inclusion of gas within the hydrocarbon liquid when the desiccating agent is reused, and thereafter reestablishing the iiow of said hydrocarbon liquid through said body of desiccating agent whereby said displacement liquid and said hydrocarbon liquid pass together into said pipe line.

4. The process recited in claim 3 wherein said gas is natural gas.

. WILLIAM E. PERDEW.

REFERENCES CITED The following references are of record in the nie oi this patent:

UNITED STATES PATENTS Number Name Date 1,431,982 Richter et al. Oct. 17, 1922 1,794,538 Palmer et al. Mar. 3, 1931 1,946,748 Lemmon et al. Feb. 13, 1934 2,273,350 Fry et al. Feb. 17, 1942. 2,323,524 Downs July 6, 1943

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