US2608520A - Sweetening process - Google Patents

Description

ug- 26 1952 E. ARUNDALE ETAL 2,608,520

swEETENING PROCESSV Filed Aug. 25. 1951 'nverzbor Gbbo'r'ag solution is withdrawn by means of line 4. The'5o "drynglaagentsffesfffon examplesi ar el` isaaisdxnown .-m.-.tr;eaui.mirfefa1p irdistnianes, as .20 Thetreaitedjfraetionlis 'introducedinto wasn: for 4example petroleum' oil`.distillateslboilingin ingZOie. IT wh'ei'ein'ii. these ranges 4with an?.alkali ..netalpliimbiteQsoluing solution'intitoduoed by reahs`-fof I inl' lieh y.tior'nsuch.es.a,..sds1ii1m,plumbiteflsolution.which.is iS AWCWSJWIJL `by 4Ili'rlsof line" 19. Th prepared by.. dissolving-lead Loxide` in anexcess foi.' Aproduct is` Withdrawn. from.. Washing ,zonel lil-by 'sodiunvhydrloxidenThe,petrolummil. and .p1um 25 'ans of.`,liiie.`2 l1"aiidmttienhaidl r'eiiied b'ite' solution aremix'edlanda' eheinioalreaction as-.desired occurs, resulting in the conversion of Arn'encapi'm'is The rivelloris' bdly" COIlihed "the to the corresponding lead meroaptides. ThesenF I' removal of objectionable melaptan and 13h10- mercaptides are. then deoomposedusually by, the.; Rheiwl. 001111301111415 f ron Virgin .0r Crackedmleeral addition of free sulfur resulting in the lead being 30 Oil fractions boiling in the range from about '757.- .niiecipitted as ainsolublelead suldeahdinthe. .769". .SuCh .@S@Splineffjlwn,....Sel e1 Iormationl of odorless. lorganic.,,clisuliiiieicom:T l. heating- 011. ,and the like utilizing ketene as the mundm vv treating' agent. UiIhe. invention'is""pitiouli"iy 1`f' ,Itfhas 'bwfbeelrr'disooieredltiiai1bbjetionafnle` adabj'ed forifithetltreatment of DeIOIeum frac- ;.merca'ptan comgounds can bedmovfed in a, 35tions`boi1ing in the "heating oil boiling range, sweetening eration utilizing ketene as.K a treatwhich fractions boil inithe range from about ing' ''g'n't Au'dmtlfijiialiil'y'f "the" fitoluin' o il's"4 350l650"Fl""If"lower boiiir'ig'fialotioiis' are "tea improved. The present invention may be readily A ed, it is preferred to Ipretreatthesefi' 'etioh's'in understood by reference to the drawingillustrati order to remove; hydrogenusuliide andthe'grelaing one-f'embodinient of the'same. O ltvely low boiling mercapta-ns` therefrmg,- `The `Referring. specifically..to .thedrawing,.a hydro.: pretreatilig-agent. preierably comprises an 'alkali carbon 'feed fraction boiling in?. the heating o il metal hydroxide solution@ as -`foinexample., `sodium *boiling range (35m-'650 Fbi-landcontaining-lner-i` hydroxide lso'lution: LA 4very. ldesirable*"inventing -eaptanslisjntroduced into the system by'means. agent comprises a sodium hydroxide liifin offline l. inthe freenon containsmydrogewsuiv145111.haviungfa.eoneentrataie inthe-fangefrtrbmwabout A-de; itispreferably passed-intoV alkalitreating 5-209 B.H

-jzonef{Where}itiiis'foontaotedfwith 'fioaustiolsolu-- Asf'pointedfoutfabove; it-f-i'svery-desirable;to "non," es rriexampie; Vsodium 'hydroxide' solution 'completely removewaterfrontlthlfeedracn. introduced by means of line 3. The spent eaustie4 VThisisaccomplishedinal dryingrizoneq-e'mpl'oying bauxite treated fraction is withdrawn from zone 2 by alumina andihxlijke, by;iil trelsinw` Nby".heating 1riirieansfoff;iineti'w:amd preferablyiintroducedfintovas Uand "IemdvingvthefWeten-bw distillationffores'trip- -.drying, zone..'6: whereinsubstantially all. watenis Ring. i removed therefrom- "Ifl: the feecii-wfyraetion,lV com Thepfraotimtolbeireatedfisiheateqito preferably to a temperature in the range from about 125-150 F. Ketene gas is introduced in the desired amount and the ketene gas and feed fraction thoroughly mixed by any suitable mixtreated fraction is washed, preferably at an elevated temperature with a satisfactory washing solution, preferably selected from the class consisting of water and Valkali metal hydroxide soing means. The amount of ketene gas added 5 lutions. If an alkali solution is employed, it is will depend on the concentration of the mercappreferred to use a sodium hydroxide solution havtans present in the feed fraction. Usually, the ing a concentration in the range from about amount 'of ketone gas added will be in the range 3-5% sodium hydroxide. A verysatisfactory sofrom about .05 to 1.5%, preferably in the range lution comprises a sodium hydroxide solution from 0.1 to 0.5% by weight based upon the feed having a concentration of 5% by weight. fraction. Just suicient ketene is added to The washing step is preferably conducted at a sweeten the hydrocarbon distillate. temperature in the range from about 125-150" F. The ketene gas may be secured by any suitable After washing, the washing solution is removed, means. A very desirable method of securing the the treated fraction is cooled and handled as deketene gas for use in accordance with the present sired. Although the invention has been deinvention is from acetone utilizing a simple scribed specificallywith respect to ketene, it is pyrolysis process. In this operation acetone is to be understood that di-ketene, methyl ketene, pyrolyzed in a. hot tube at a temperature of diphenyl ketene and the like may also be used. 11001400 F. with a short contact time in order Mixtures of ketene and di-ketene are also effecto decompose the acetone in accordance with the 2Q tive. e following equation: i:The present invention may be further unders ood by reference to the following example illus- CHSCOCH rv CH2-450 +0114 treurig the seme;

acetone Y kerine methane VSweetening runs were carried out on samples Methyl ketene een be made in e similar 2s of West Texas P. c. naphtha. heavy virgin nephmanner from methyl ethyl ketone. The methane tha, Virgin heating Oil and a S0111 Caked Daphniay be removed and the ketene then contacted tha- In mOStCaSeS these feed Stocks Were Washed 4with the .feed fraction wherein it is believed that with Caustic Soda Solution and ltered prior .t0 thefouowng reaction occurs: use. This pretreatment considerably reduced l y 30 the ketene requirements. In the runs, 750 cc. of CH2=CO+RSH Q CHSCOSR the sour distillate were placed in a seltzer bottle serene ntigemler thieesier and the ketene generator product was'passed in Y n p Y at room temperature for a period of time necesyThe time of contact between the'ketene gas 1 sary to obtain the desired amount of ketene. vand the feed fraction may vary appreciably., and vThe bottle wasthen closed and placed on a rois dependent on the treating temperature but is tating wheel for one-half hour at a'temperature generally in the range from about 2 to V30 minutes. of 135 F. The bottle was Athen cooled to room A preferred time of contact is in the range from temperature, the contents removed, Washed three about 10 to 30 minutes. Mineral acid catalysts minutes With 100 cc. of water and then ltered. such as sulfuric acid, phosphoric acid and the o A copper number and doctor test were then oblike can also be used in catalytic amounts (less tained on the product.V fthari 2%) to improve the ketene sweetening op- The results are presented in Table I and it will eration. be noted that, even Vwith high copper number The mixture, after a 'sufficient time of constocks, contacting with 0.1-0.4 weight per cent tact, is handled in a manner to remove excess ketene (based on feed) results in sweet products Aketene gas which is preferably recycled.V The possessing copper numbers of 1.0 or below.

Table I Operation 1 2 3 4 FeecL.) Sour Cracked West Texas Virgin Heating West Texas P. C. NaphtliaV West Texas Heeey f Naphtha, Boil- Oil (lrewashed 2%-15 Bc. (Prewashed with equal vol. Naphtha (Prewash'ed ingl Range 160- caustic), Boiling Range of5% NaOHsoLunder Ni),d .with equal vol. of 5% 440 F. d50-650 F. Bolling Range 100-275 F. NaOH under Ne).-

Boiling 'Range 26D- Feed Inspections: v

, Copper No. as Recd 3.0 88.5 10 3o Copper No. after H2O wash 2. 0 84. 0 10 28 0. aat o. s4 l0. 71s o.l 79s j Treatment#l Per Cent Ketene by weight en Feed l0.13 l-0.26 0.070 0.115 10.187 I 0.167 0. 231 0.36 0.225 0 37 Product Inspections: p l

'Copper N0 1.0 0.5 31.0 1.0 1.0 1.0 1.0 1.0 1,0 1,0

Doctor TestA DNP Pass DNP DNP Pass DNP DNP Pass Pass i Pass;k

.e 750 cc. sample placed in seltzer bottle and ketone generator prcductpassed in at room temperature (unlessotherwise indicated) for a period Yof time necessary to obtain desired amount oi ketene. Bottles closed and mixed for 0.5 hr.

water, separated and filtered. Inspections then obtained on product. b Ketene adsorbed in naphtha at alcohol-Dry Ice bath temperature;

at F., cooled, product washed 3 min. with 100 'K I 750 cc. ol feed washed 3 min. with 100 cc. water, separated and filtered.

l To remove HiS and reduce copper number from 68 t0 l0. I To reduce copper number from 38 to 30.

l Theoretical ketone requirement for a stock of this Cu No.=0.l4% The copper number is the milligrams o mercaptan sulfur present ammonium sulphate solution.

AThe doctor test is a means of making sure that hydrocarbon fractonsare the hydrocarbon is shaken witn a sodium plumbite solution and a trace of free sulfur'havc-not changed color, mercaptans are absent, the stock is "sweet and the doctor test i5 are present and the test does not pass (DNP").

Lrco of mercaptans `which render the fraction soun sulfur. If after shaking, the hydrocarbon, plumbite solution, and Pass It discoloration occurs mercaptans What is claimed is:

1. Process for the removal of mercaptan compounds from a petroleum oil containing the same which comprises contacting said petroleum oil with a treating agent comprising ketene.

2. Process as defined by claim 1 wherein said petroleum oil boils in the heating oil boiling range.

3. Process as dened by claim 1 wherein said oil is contacted with said ketene at a temperature in the range from about 100 to 300 F.

4. Improved process for sweetening a petroleum oil boiling in the range below about 700 F. which comprises contacting said oil in an initial stage with an alkali metal hydroxide solution, removing the treated oil from said initial stage and processing the same in a secondary stage in order to substantially completely free said oil of water, thereafter heating said oil to an elevated temperature and contacting the same in a tertiary stage with a treating agent comprising a ketene,

removing said treated oil from said tertiary stage and processing the same in a final stage with a washing reagent in order to produce a treated product.

6 5. Process as defined by claim 4 wherein the temperature maintained in said nnal stage is in the range from about 125 to 150 F. and wherein said washing agent comprises water.

6. Process as dened by claim 5 wherein said oil is heated to a temperature in the range from about 125 to 150 F. prior to contacting the same with ketene.

7. Process asdeiined by claim 6 wherein said oil comprises an oil boiling in the heating oil boiling range.

ERVING ARUNDALE. JOHN P. THORN.

REFERENCES CITED UNITED STATES PATENTS Name Date Feasley June 13, 1950 Number

Claims (1)

1. PROCESS FOR THE REMOVAL OF MERCAPTAN COMPOUNDS FROM A PETROLEUM OIL CONTAINING THE SAME

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