CA1318876C - Process to improve the demulsification of bitumen in pond oil - Google Patents

Abstract

ABSTRACT
A process for the recovery of bitumen from pond oil by breaking the aqueous pond oil emulsion with an aluminum poly-hydroxy polymer having a hydrolysis ratio (OH/Al) of from about 2 to about 2.2 or a combination of said polymer with a demulsifier, allowing the treated emulsion to stand until water released from the emulsion is coalesced and separating the bitumen.

Description

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P~5S~ T~ IMPR~V5 TH~ ~MUL8I~ICATION
OF BITUMEN IN PON~ OIL
ThlE lnventlon 1~ dlrected to a novel ~ethod to enhance the demul~l~lcation o~ bltumen ln pond oil, whlch 1E g wa~te product ln the conver~ion oP tar candE to petroleum product~, and thereby enable the ~ltumen ln the pond oll to be ~ore e~lclently recovered.
BACKGROUN~ O~ THE INVENTION
Tar ~and~ (~hlch are al~o known aB oll ~and~ and bltumlnou~ E~nde) are ~and depo~it~ whlch are lmpregnated wlth den6e, vlOEcou~ petroleum. Tar ~ando are found throughout the world, o~ten ln the same geo~raphlcal areaE ae conventlonal petroleum. The large~t depo~lt, and the only one o~ preEent commerclal l~portancep l~ ln the Ath~baEca reglon in the northeaæt section oP the provlnce o~ Alberta, Canada. Whlle ~uch o~ the Athaba6ca depo~lt le not econo~ically recoverable on a com~erclal ecale wlth current technology, nonethele~ ub~tantial portion 1~ sltuated at, or very near, the ~ur~ace ~here lt ~ay ~airly rsadlly be ~lned and procee6ed lnt~ synthet~c crude oll, and thl E
procedure 1~ belng carrled out co~rclally on a very large ecal~ by Great Canadlan Oil Sand~ ~now Suncor, Inc., Oll Sandæ Dlvlslon) ~nd by Syncrude neAr Fort Mc~urray, Alberts.
AthabaEca tar 6andE i8 a three-component ~lxture o~
bltu~en, ~lner~16 and ~ater. Bltumen lx the valuable component ror the extractlon Or whlch t~r s~nd~ are mlned and proc~s~ed. Th~ bltumon cont~nt 16 v~riable~ avera~ln~ 12 wt~

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o~ the depoElt, hut ranging ~rom zero to 18 wt~. Water typlcally runE 3 to 6 wt$ o~ the ~lxture, and gener~lly lncreasea AE the bltumen content decrea~ee. The mineral content is relatlvely con~tant, ranglng ~rom ~4 to B6 wt~.
While Eeveral ba6ic extractlon methodls to ~eparate the bltumen Prom the eand have been known ~or many yearE, the rhot water~ proce~s 18 the only one o~ preRent commerclsl ~lgni~lcance and 1~ employ~d by both Suncor and Syncrude.
The hot water proca~s ~or achleving prl~ary extractlon o~
bltumen ~rom tar ~and consiEtE o~ three m~Jor ~rocesE EtepE
(a fourth 3tep, ~lnal extrattlon, 1~ uæed to clean up the recovered bitumen ~rom down6tream proceE6~ng). In ~he ~lr6t ~tep, called condltlonlng, tar 6and 1E mlxed wlth water and heated wlth open steam to form a pulp o~ 70 to 85 wt~ 801 lde.
Sodlu~ hydroxlde o~ other reagents are sdded a8 required to ~aintaln pH i~ the r~nge oP 8.0-3.5. In the Eecond ~tep, called ~epar~tlon, the condltl~ned pulp 1~ ~lluted ~urther 60 that Eettllng c~n take place. The bulk oP the Eand-61 e ~lneral rapldly æettle6 and 1~ ~lthdrawn aE 3and talllng~.
Mo6t o~ the bltumen r~pidly 210at~ (eettleE upwerdly~ to ~or~
a coherent ~a~ known as ~rot~ whlch ~1E recovered by 6klmmlng the 6ettlln~ ve6Eel. A thlrd stream, cslled the ~iddlingE
drag 6treanr a~y be w~thdrawn ~ro~ the ~ettling veEoel and oubJected to a thlrd proces61ng ~tep, ocavenging, to provlde lncremental recovery o~ suspended bltumen.
~ he throwaway ~atarlal ~rom above extractlve proceEElng 1~ re~rred to a~ t~lllngs and these talllng~ are an aqueouE

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EuepenElon o~ mineral~ ~ e~nd and other min~r~l ~in~el~ and bltu~en and thl~ ~ludge 1~ dlEcharge~ to l~rge lagoonE or ponds. Over tlme, the tallin~E ~ludge matureE~ causlng the bltumen ln the talllngæ di~charged tD the pond to coagulate to Eo~a extent and for~ an lrregular layer o~ varylng thlckneE~ Eu6pended between the compresEed higher denslty bottom æludge and the lower den~lty upper aqueous layer.
It 1~, o~ course, desirable to recover the bltu~en ~rom the lagoon and i~ the locatlon and thlckne~E o~ the ~u6pended bitu~en iB known, an approprlate pump can be uEed to remove lt. Thls bltu~en 16 recovered as an aqueous emulElon and thl~ emu}~lon, re~erred to hereln aE Upond oll,~ le extremely stable and dl~Xlcult to co~pletely break wlth the commonly available demul6i~1ers.
ThiE lnventlon 1~ dl~ected to breaking ~uch bitu~en-contalnlng pond oll emul~l~Ds ~nd recoverlng the bitumen ~rom the water coalegced by th~ procee6 of the lnventlon.
ISCUS~ION OF THE PRIOR ART
Numerous de~ulsl~ler6 are }cnown ln the prlor art and although BOme o~ the~ do sho~ demulsiflcation e~ect~ wlth pond oll, thelr e~activene~E iE lnadequate ~or economlc bltum~n reco~ery ~ro~ ~ond oil. Typlcsl o~ such emul~l~ler~
are: (1) D-415 ~nd D-416 whlch ara blend~ o~ polymer~ ln a mlxture o~ a heavy aro~atic 801vent, xylena and lsopropyl alcohol; ~2~ D-42~ whlch 1E a polymer blend ln an aromatlc solvent ~nd methanol; ~3) 5E-~0 whlch is a polyal condensate ln a hl~h bolllng polnt alkylaromatlc ~olvent. D-gl5, D-~16, ~3~$~7~

and D-420 are manu~actured by Unlted Oil~leld ChemlcalE, Ltd.
o~ Ni~ku, Alberta, Canada, and 5E-40 ls manu~Acturéd by Alchem, lnc. ln Burllngton, Ontarlo, Canada. The demul~l~ler a~entE D-415, D-416, and 5E-40 are ~oluhle ln aromatic solvente such ~E toluene. D-d20, however, le a water di~per~lble agent. ~oth typee o~ demul61~1er~ may, o~
cour~e, be u6ed. ~ecauce o~ thelr rel~tlvely high CoEtE
and~or low e~lclen~y, none o~ theEe agentE by the~elve6 are totally ~atlOE~actory ~E demul~l~ler6 ~or recoverlng bltumen ~roM pond oll.
BRIEF 8TATEMENT OF THE I~VENTION
In accord with thl6 lnventlon, recovery o~ bltu~en ~rom pond oll lo enhanced by treatlng pond oll wlth an alumlnum hydrnxy polymer havlng a hydroly~l~ ratlo o~ ~rom about 2.0 to about 2.2 or wlth a comblnatlon o~ an emulElon l~reaking che~lcsl and t~ alumlnu~ polyhydroxy polymer wherein the ratlo o~ hydroxyl group6 to alumlnum atom~ ~the hydroly~ls ratlo) 1 between about 2.0 and about 2.2.
More partlcularly, the inventlon comprl~e~ a proceE~ ~or the recovery o~ bltu~en ~rom an aqueous emulslon o~ pond oil obtalned ~rom the w~Ete ta~ la~oon6 og oll sandE
proces~lng by treating ~he pond oil ~lth an aluminum polyhydroxy polymer havlng a hydrolysl~ ratlo o~ ~rom about 2.0 to about 2.2 or wlth ~uch poly~er and a commerclal demul61~1er to break the emul~lon~ allowlng the treated eoul~lon to stand untll water ~ro~ the broken emul610n 18 coalesced and r~coverlng the bltumen~

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D~AIL~D D~5CRIPTION OF THE INVENTION_ _ _ _ A~ lndlcated above, the eeEence o~ thlE lnvention llee ln the use o~ an alumlnum polyhydroxy polymer. This polymer i~ po~ltlvely charged and 1~ characterlzed by havlng an alumlnum atom ln a tetr~hedral con~lquratlon, whlch alumlnum atom 1~ surreunded by twelve alumlnum ato~s In ~n octahedral con~lguratlon and the remalnlng valences o~ thle polymer l~
co~pri~ed o~ hydroxyl group~. ThlE lnorganlc poly~er 16 quite 6table up to a temperature o~ about 500C. Re~erence to th1~ poly~er and lt~ preparatlon wlll be ~ound ln the -artlcle by J. Y. Bottero et al entltled ~Mechanlsm of - Formatlon o~ Aluminum Trlhydroxide ~rom Kegqln Al~
Poly~er~," Journal o~ Collold and Interface 8clence, Vol.
117~ No. 1, M~y 1987, page~ 47-57.
The alumlnu~ polyhydroxy polymer appears to have ceveral poeltlve ef~e~t~ on the pond oll e~ul~isn. One e~ect ls that lt desta~illze~ the partlculate clay mlneral6 ln the pond oll e~ul~lon cauelng tho6e partlculates to settle as an enlarg~d porous volume and thereby taklng the water droplet~
with the clay ~inerals~ It i~ the e~cape o~ these wster molecules th~t tendE to e~ect a sllght demursl~lcatlon.
But more ~lg~ antly, a second bene~lclal effect 1~
belleved to be due to the po~ltlve charge~on the alu~lnum polyhydroxy polymer. Durlng the proceOE61ng o~ the oll ~and~, the uEe o~ cau~tlc and the oxldstlon whlch occur6 over tlme CreateE Eur~ace actlve agentE whlch generally have a negatlve charge due to the carboxyl group~ on ~uch sur~actant $ 7 ~
molecules Such a~ent~; act t:o ~3t~0~ly.1y enlu.Lslfy tlle bitumell in the pond oil. The positively chacged alumillum polyhydroxy polymer, however, is believed to absocb ~he negatively charged ~urfactants and thu~, tl-e dellluLsifiecs may readlly demulsify the ~y~tem wher~by the wateL pcesent iB coalesced ~nd the bitumell released for recovery.
The aluminum polyhydroxy polymer is ceadily pcepared just before use by reaction of sodium hydroxide with alumillum chloride or othec wa~er soLuble alu~ ulll salt. In p~epaLing a ~lu~ ttl~ L~lylll~r, Ill~laL alll~u~ ~L ~ r~ay~ s ace pref~cably used so as ~o yive a hydrolysis ratio ~i.e., a molar ratio of OH/Al) of from abou~ 2.0 to about 2.2. Thus, for a ratio of 2.2, 1.1 mole of NaOH and ~.5 mole of aluminum chloride will be used. This ratio is in-portant il~ ordec to achieve the proper configuration of aluminum atoms refecced to above. Alternatively, the polymer may be made with a higher OH/Al ratio and the pcoduct so obtained therl be diluted with an appropriate amount of alum solution so as to reduce the ratio between about 2.0 and 2.2. Thus, for example, a liquid sodium aluminate solution which has an OH/Al ratio of 5 (com-mercially available a~ HAN-FLOC 45 fcom Hydco-Tech Limited, New Westminster, Briti~h Columbia and is a trademark of Handy Chemicals of Montreal) may be diluted with an aluminum chloride or alum solution to the desired catio.
In carrying out the pcoces~ of the invention, an aqueous ~olution of the aluminum hydcoxy polymer is added to the pond oil with or without the comlllercial demulsi h er and, after ,~, ' .

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mlxlng, much o~ the water ~rom the broken emul~lDn 1E
coalee~ed. The bltumen 1E then readlly recovered by ~entrl~ugln0 or other meane and taken ~or ~urther proceEEing.
Ae lndlcated, the aluminum polyhydroxy polymer ~ay be used alone, but lte per~ormance ulll vary to some extent wlth the partlcular ~ource o~ pond oll. In tho6e in6tance where the e~e~t o~ the polymer le o~ limlted per~ormance, lt 16 de~lrable to ~e the polymer ln co~blnatlon wlth ~ommerclal demul61~1erE to get an addltlve e~ect. Slnce the alumlnum polymer 1~ leeE ca6tly than the emulsl~lers uæed, the co~binatlon re6ultE ln a more e~icient pro~es6 at leeE CoEt than u6e o~ hlgh concentratlonE o~ emulsi~ler6 alone. The demulsi~ylng amount6 o~ materlal~ used are not crltlcal, but ln general, both the co~mercial emulE1~1er and alu~lnum polymer will be uEed ln an amount o~ ~rom ~bout 25 to about 100 psrtE per ~llllon (ppm~ o~ pond oll. It wlll be under~tood that ln order to obtaln optlmum economlcs and per~orm~nce, the pre~erred a~ount~ o~ each agent wlll be deter~lned by exp~rl~ntv n order to ~urther exempll~y the lnventlon, the ~ollo~lng axa~les are glven.
~vperi~e~l rocodure~
Prepa~atlon o~ Alu~ln~m Polyhydroxy Poly~er A eolutlon o~ the alumlnum polyhydroxy poly~ar was prepared by the addltlon o~ an aqueous 601ution o~ 1.1 M
NaOH to a otlrr~d 0.5 M aqueous alumlnum chlorlde eolutlon at a rat~ o~ about 3 ml.~mln. and at a tempersture o~ about 13 t ~ 7 ~

20~C. Ths hydrolysl6 ratio ~OH/Al) Or the re~ultlng lnorganlc poly~er wae 2.2.
Demul6i~1er~ ~valuated Co~merclally avallable demul61~1er~ were ueed in the evaluatlons and theee were D-416, D-420, and 5E-40 re~erred to above.
Pond Oil Sa~ple The pond oll u6ed ln the evaluAtlon wa~ taken ~ro~ a commercial talling~ pond at the Suncor, Inc. oll Eand~
procesElng plant at ~ort McMurray, Alberta. Thl6 materlAl contalned vl61ble ~ree ~ater whlch wa6 removed hnd the sa~ple then subJected to analysl~ a6 ~ollows:
WIW%
Bltumen 50.6 Mlnerale 1.4 Nater 41.3 Llght Hydro~arbon~ 6.7 Durlng the proce~Eing o~ the oi l ~nds a hydrocarbon dlluent i6 added to the recovered bltumen ~roth ln order to ~acllltate a centrl~ugatlon step. So~e o~ thlE dlluent ultlmately accumulate6 ln the pond oll and ln order to ~aintaln a c3n6Igt~nt ~tandsrd for the experimental evaluatlons the ratlo o~ diluent to bltumen ln the pond oll (~ro~ whlch the ~ree water ha6 been removed) 18 ad~u6ted with toluene to a ratlo o~ 0~6.
Experlmental Demul61~1catlon Procedure A 78 ml~ ~a~ple o~ the pond oll wlth spproprlate amount6 . ..

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o~ alumlnum hydroxy polymer alone or wlth a demul~l~ler waE
placed ln a 100 ml. c~paclty centrlfuge tube and 22 ml. Or toluene ~dded to reduce the vi~co~lty. The contents o~ the centrlfuge tube ware thoroughly ml~ed and held ln a hot water bath at 82C. Por 10 minute6. The heat~d test Eample wa~
then centrl~uged at 2000 r.p.m. ~or 10 mlnuteE whereby the cont~nts of the tube were 6~parated lnto a small bottom sediment lay~r of ~ilt and clay8, a ~oder~te ~lddle layer o~
wate~ and a large upper layer of bitumen which contained æome waterO
The bltumen layer wa6 then separated of~ and sub~ected to water analyEl~ by the Dean Stark method.
Experl~ental Result6 The ables whlch ~ollaw show the e~ectlvene6E of the uEe o~ the alu~num polyhydroxy polymer ln conJunctlon wlth co~mercl~l de~ulEl~lerE. The lower the amount of water ln the recovered bltumen, the greater the eP~ectivene~ oP the treatment. The term ~polymer~ u~ed ln the tables refers Lo the alumlnum polyhydroxy polymer. It wlll be observad that the alu~lnum polyhydroxy poly~er alone i6 ef~ective ln reduclng the amount of water ln the rscovered bltumen and the e~ul~ifler alone ~l~o show6 Eome effect. However, by uæe of both of th~ agentE and when the polymer læ u6ed at ~pproprlate concentratlon~, the water reduclng efract 1E most pronounced. The percent l~prov~ent due to the polymer alone aæ shown ln the tables 18 calculated by dividing the dlPference between the vslueE ~or percent water where no ~ 3 ~

demulei~ler 1E u~ed and the control value o~ each table by the control value and multlplylng by 100. The total percent lmprove~ent re~lect~ the per~ormance due ko the slumlnum polymer ln comblnatlon wlth the demul~i~ler and and i8 calculated by dlvldlng the dl~erence betweel~ the valueE ~or percent water where both the aluminum polymer and demulsl~ler are used ~y the control value and ~ultlplylng by 10~.
Ae can be oeen ~rom the tablee whl~h i'ollow, the u6e 0~
alumlnum polyhydroxy polymer alone or ln comblnatlon wlth the ~o~erclal dem~lsi~lerE 18 qulte bene~lclal ln dewaterlng ~e.g., demul~l~lcatlon~ o~ the pond oll. In the exa~ple~
glven the percent improvement ~or u~e o~ the alumlnum polymer alone range~ ~rom about 1.5~ to about 41~. ~ven the lower value o~ 1.5~ 1E a very signi~l~ant bene~lt becauee o~ the very large volume~ oP pond oll proceseed ~or recovery D~
bitumen. It i~ al~o evldent ~rom the data thst the uee oi' alumlnu~ poly~er ln comblnatlon with co~merclal demul~l~ler ~lgnl~ica~tly ln~res~es the recover~ ~f ~ltu~en ~rom pond oll over use oi' the de~ulEi~ier alone.

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Table 1 Percent Water Remalning ln Bltu~en Layer a~ter Treat~ent wlth Polymer and D~16 Polymer ~ml./lO0 ml. ~ampl~) D-416 ~ppm) 0.0 0.25 0.75 1.0 O.Q 20.2~ l9.g 19.3 16.4 15.7 15.4 14.6 13.9 13.~ 13.2 12.7 11.9 100 12.9 12.9 12.7 12.1 *Control Value Percent Improve~ent Polymer Concentratlon tml-/100 ml.) D-416 ~ppm) 0.0 0.25 0.75 1.0 0.0 Due to polymer alone --- 1.4g d.46 1~.81 Due to poly~er alone --- 1.91 7.01 11.46 Total ~ I~prove~ent 22.39~ 23.~8 27.86 ~1.34 Due to polymer alone --- 1.49 5.22 11.19 Total % Improvemsnt 33.66' 3~.65 37.13 dl.09 ~00 ~ue to polymer alone --- 0.00 1.55 ~.20 Total % I~provement 36.1~ 36.14 37.13 ~0.10 ~I~prove~ent due only to demulslfler ~3~ 8~

Table 2 _ Percent W~ter R~msining ln ~ltumen Layer a~ter Treatment ~lth Polymer and 5E-40 Polymer (ml./100 ~ ample) 5E-40 (ppm) 0.0 0.5 1.0 0.0 22~* 19.6 16.6 19.2 16.0 15.7 100 1~.9 14.2 13.a *Control value Percent I~_ovs~ent Polym~r Con~entr~tlon ~mlO/lOQ ml.) 5E-40 ~ppm) 0.0 0.25 1.0 0.0 Due to polymer ~lon~ 14.04 27.19 Due to poly~ r alone --- 16.67 18.23 Total % I~proved 15.79 29.82 31.14 Due to polymer alone --- 24.87 26.9 Total ~ Improved 17.11~ 37.72 39.47 ~Improve~ent due only to de~l~l~ier 7 ~

Table 3 Percent. Water Rem~inlng ln Bltumen L~yer a~ter T~eatment wlth Polymer and D-420 - ~ (ml L~ ml ~, Eample ) D-420 (ppm) 0.0 0.5 1.0 0.0 23.3~ 1.7 21.2 19.4 17.d 100 19.2 19.1 16.8 ~Control v~lue Percent Improvement Polymer Concentratlon (ml./100 ml.) D-420 ~pp~) 0.0 50 100 0.0 Due to polymer alone -~ 21.70 Due to polymer alone --- 8.49 17.92 Total ~ I~proYed 9.01~ 16.7~ ~5.32 Due to polymer alone --- ~.52 12.50 Tctal ~ Improved 17~hO~ 18.03 27.90 Improvement due ~nly to demul~l~ler

Claims (6)

1. A process for the recovery of bitumen from an aqueous emulsion of pond oil obtained from the waste tailings lagoons of oil sands processing which comprises treating said pond with a demulsifying amount of aluminum polyhydroxy polymer wherein the hydroxyl to aluminum ratio is between about 2.0 and about 2.2 to break said emulsion, allowing the treated emulsion to stand until water from said broken emulsion is coalesced and recovering said bitumen.

2. The process of Claim 1 wherein the amount of said aluminum polymer used is from about 25 to about 100 ppm of pond oil.

3. A process for the recovery of bitumen from an aqueous emulsion of pond oil obtained from the waste tailings lagoons of oil sands processing which comprises treating said pond oil emulsion with a commercial demulsifier and an aluminum polyhydroxy polymer wherein the hydroxyl to aluminum ratio is between about 2.0 and about 2.2 to break said emulsion, allowing the treated pond oil to stand until water from said broken emulsion 18 coalesced and recovering said bitumen.

4. The process of Claim 3 wherein the demulsifier and the aluminum polyhydroxy polymer is each used in an amount from about 25 to about 100 ppm of pond oil.

5. The process of Claim 4 wherein the demulsifier is soluble in an aromatic solvent.

6. The process of Claim 4 wherein the demulsifier is water dispersible.