CA1301692C - Process for flocculating recycle water from oil sands processing to effect efficiencies - Google Patents
Process for flocculating recycle water from oil sands processing to effect efficienciesInfo
- Publication number
- CA1301692C CA1301692C CA000559659A CA559659A CA1301692C CA 1301692 C CA1301692 C CA 1301692C CA 000559659 A CA000559659 A CA 000559659A CA 559659 A CA559659 A CA 559659A CA 1301692 C CA1301692 C CA 1301692C
- Authority
- CA
- Canada
- Prior art keywords
- oil sands
- water
- flocculant
- flocculating
- separation cells
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
- B03B—SEPARATING SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS
- B03B9/00—General arrangement of separating plant, e.g. flow sheets
- B03B9/02—General arrangement of separating plant, e.g. flow sheets specially adapted for oil-sand, oil-chalk, oil-shales, ozokerite, bitumen, or the like
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
- C10G1/04—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal by extraction
- C10G1/047—Hot water or cold water extraction processes
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- Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Organic Chemistry (AREA)
- Wood Science & Technology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Geology (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
Abstract
ABSTRACT
In the process of recovering bitumen from oil sands wherein the oil sands are subjected to a hot water extraction comprising the steps of conditioning the oil sands, settling the conditioned oil sands in separation cells and subjecting the middlings layer to a scavenging step, the improvement of flocculating the discharge from the separation cells and/or scavenger circuits and recycling the released water to the conditioning step and separation cells.
In the process of recovering bitumen from oil sands wherein the oil sands are subjected to a hot water extraction comprising the steps of conditioning the oil sands, settling the conditioned oil sands in separation cells and subjecting the middlings layer to a scavenging step, the improvement of flocculating the discharge from the separation cells and/or scavenger circuits and recycling the released water to the conditioning step and separation cells.
Description
13~16~Z 87-003 PRO~ESS FOR FLO~CULATING RECYCLE WATER FROM OIL
SANDS PROCESSING TO EFFECT PROCESS EFFICIENCIES
BACKGROUND OF THE I~VENTION
ThlE lnventlon relateE to an lmprovement ln the proce661ng of recycle water ~rom oll Eand6 operatlon6 whereln bltumen 16 recovered ~rom tar Eand6 whlch are EubEequently converted to petroleum product6.
In the hot water extractlon procesB of oll ~and6 (al~o known a6 tar Eand6) ln the northeaEt provlnce o~ Alberta, Canada, the extractlon method comprl6e6 three maJor proce6s 6tep6 plus a flnal extractlon u6ed to clean up the recovered bltumen ~or ~urther proce661ng. In the ~lr6t 6tep, called condltloning, oil 6and 16 mlxed with water snd heated with open steam to i'orm a pulp o~ 70-85 wt.~ 6011d6. Sodlum hydroxlde or other reagent6 are added a6 requlred to malntaln the pH ln the range o~ about 8.0-8.5. In the 6econd 6tep, called 6eparatlon, the condltloned pulp 16 dlluted ~urther with hot water 60 that separation can take place. The bulk o~ the sand-612ed particle6 ~greater than 325 me6h Ecreen) rapidly 6ettle6 and 16 wlthdrawn a6 6and talllng6. Mo6t o~
the bitumen rapldly float~ (6ettle6 upward) to i'orm a coherent ma66 known a~ bitumen froth whlch i6 recovered by 6klmmlng the 6eparation ve66el. An aqueou~ middllng6 layer containlng 60me mineral and bitumen i6 formed between the6e layerE. A ECavenger 6tep may be conducted ln the mlddllng6 ~$
13~16~2 layer ~rom the prlmary Eeparation Etep to recover addltlonal amountE o~ bltumen thereSrom and thls Etep usually comprl~eE
aeratlng the mlddllngs. The frothE recovered from the prlmary and the Ecavenger 6tep can be combined, dlluted wlth naphtha and centrl~uged to remove water and mlnerals. The naphtha 1E then dlstllled ~or further proceEElng. Hot water proceEEeE are deEcrlbed ln Canadian Patent NumberE B82,668;
866,226; 891,472; 892,548; and g73,500. TalllngE can be collected Srom the a~orementloned proceEslng Eteps and generally wlll contaln Eolld6 aE well a~ dlEEolved chemlcal6.
l'he talllngE are collected ln a retentlon pond ln whlch addltlonal 6eparatlon occurE. The talllng6 can alEo be consldered aE proceEElng water contalnlng EolldE whlch are dlEcharged ~rom the extractlon proceEE. The talllngE
comprlEe water, both the natural occurrlng water and added water, bltumen and mlneral.
Condltlonlng tar EandE Sor the recovery oS bltumen conElEtE oS heatlng the oll Eand/water mlxture to proceEE
temperature (180-200F.), phy61cally mlxlng the pulp to unlform compoEltlon and conEiEtency, and the conEumptlon ~by chemlcal reactlon~ oS the cauEtic or other added reagentE.
Under theEe condltlonE, bltumen 1E Etrlpped Srom the lndlvldual Eand gralns and mixed lnto the pulp ln the Sorm oS
dlEcrete dropletE o~ a partlcle Elze on the 6ame order aE
that oS the Eand graln6. ~urlng condltlonlng, a large fractlon of the clay partlcle6 become6 well dlEperEed and mlxed throughout the pulp. The condltlonlng procesE whlch 13~6~
prlepares bltumen for efflclent recovery durlng the following proceEE stepE alEo caUEeE the clayE to be the moEt dlfflcult to deal wlth ln the talllngE dl6poEal operatlon.
The other proceEE Etep, called ~eparatlon, 1 actually the bltumen recovery Etep, the Eeparatlon havlng already occurred durlng condltlonlng. The condltloned oll sand pulp 16 Ecreened to remove rock~ and uncondltlonable lumps of tar EandE and clay. The re~ect materlal, ~Ecreen overEize,~ is dlEcarded. The Ecreened pulp 1E further dlluted wlth water to promote two Eeparatlon proceEEes. Globules of bltumen, eE6entlally mlneral-free, float upward to form a coherent maEE of froth on the Eurface of the Eeparatlon unlt6; and, at the eame tlme, mlneral partlcleE, partlcularly the Eand Elze materlal, Eettle down and are removed ~rom the bottom of the Eeparatlon unlt aE OEand talllngE. TheEe two Eettllng procesEeE ta~e place through a medlum called the mlddllngE.
The mlddllngE conElEt prlmarlly of water, bltumen partlcle6, and Euepended flneE.
The partlcle ElzeE and denEltles of the Eand and of the bltumen partlcleE are relatlvely flxed. The parameter whlch ln~luenceOE the 6eparatlon proceEEeE moEt 1E the apparent vlEcoElty of the mlddllngE. CharacterlEtlcally, aE the EuEpended materlal content rlEeE above a certaln thre6hold, whlch varle~ accordlng to the compoEltlon of the EuEpended flneE, apparent vlEcoElty rapldly achleveE hlgh valueE wlth the ef~ect that the Eeparatlon proceE6eE eEEentlally Etop.
Llttle or no bltumen 1E recovered and all EtreamE exltlng the 13~16~Z
unit have about the 6ame compoeltlon 9E the ~eed. Ae the feed Eu6pended flneE content lncreaeee, more water muet be uEed ln the proceEE to malntaln mlddllng~ vlEcoElty wlthln the operable range.
The thlrd Etep of the hot water proceEE 1E ECaVen91n9 The feed of 6u~pended flneE content determlne~ the proce~
water requlrement through the need to control mlddllng6 vlEcoElty whlch, as noted before, 1E governed by the clay~water ratlo and the type o~ clay mineralE. It 16 uEually neceEEary to wlthdraw a drag Etream of mlddllngE to malntaln the Eeparatlon unlt materlal balance, and thlE
Etream o~ mlddllng& can be Ecavenged for recovery of lncremental amount6 o~ bltumen. Alr ~lotatlon 1~ an e~fectlve Ecavenglng method ~or thlE mlddllngE Etream.
Flnal extractlon or froth clean-up 1E UEUa11Y
accompllEhed by centrlfugatlon. Froth from prlmary extractlon le dlluted wlth naphtha, and the dlluted froth 1E
then 6ub~ected to a two Etage centrlfugatlon. Thl6 process yleldE an oll product of eEsentlally pure, but dlluted, bltumen. Water and mlneral and any unrecovered bltumen removed from the froth conEtltuteE an addltlonal talllng Etream whlch muEt be dlEpoEed.
In the termlnology o~ extractlve proceEElng, talllngE
are a throwaway materlal generated ln the cour6e of extractlng the valuable materlal from the non-valuable materlal. In oll ~andE proceEElng, talllngE con~lst of the whole oll Eand~ plu6 net addltlonE of proceEE water leEE only 13~316~Z
the recovered bltumen product. 011 ~and tall lngE can be 6ubdlvlded lnto three categorle6~ creen overElze;
~2) Eand talllngs--the fraction that EettleE rapldly, and (3) mlddllng~--the fractlon that settles slowly. Screen overElze 1~ typlcally collected and handled aE a ~eparate stream .
Talllngs dlsposal 1~ the operatlon regulred to place the talllngE ln a flnal reEtlng place. ~ecauce the tailings contaln bltumen emulElon6, flnely dlEperEed clay wlth poor Eettllng characterlEtlcE and other contamlnantE, water pollutlon conElderatlons prohlblt dlEcardlng the talllngs into rlvers, lakeE, or other natural bodieE. Currently, the talllngE are ~tored in retentlon pondc whlch lnvolve large 6pace requlrementE and the conEtructlon of expenslve encloEure dlkeE. A portlon o~ the clear water layer at the top o~ the talllnq6 pond may be recycled back lnto the water extractlon proceEE a6 an economlc mea6ure to con6erve water.
Currently, two maln operatlng mode6 ~or talllng6 dl6posal are: ~1) dlke bulldlng--hydraullc conveylng of taillng6 followed by mechanlcal compactlon of the 6and talllngs fractlon; and (2) overboardlng--hydraullc tran6port wlth no mechanlcal compactlon.
The pre6ent lnventlon 16 dlrected to the water ln the talllngE from the 6eparatlon cellE and/or the 6cavenglng clrcultE whlch, ln accord wlth the lnventlon, 16 recycled back lnto the water extractlon proceEs and provldeE for i~proved proceEE e~flclencleE and lmproved proces6 economlc6.
13~169Z
~UMMARY OF THE INVENTION
The proceE6 of the lnventlon lnvolveE flocculating the dl6charge from the 6eparatlon cellE and/or the scavenger clrcults employed ln the oll Eands proce~sing and returning to the condltloning drumE and Eeparatlon cells water recovered from the flocculated talllngE. As a result of the proce6~ of the lnventlon, water conEervatlon, energy 6avlngs, lncrea6ed bltumen recovery, and other beneflt6, a6 wlll be detalled later, are obtalned.
DESCRIPTION OF THE DRAWINGS
Flg. 1 16 a 6chematlc flow dlagram of water uEe ln the ol1 sand6 extractlon proce6s as presently practlced.
Flg. 2 16 a echematlc flow dlagram 6howlng the flocculatlng 6tep of the lnventlon and recycle of the water from the flocculated talllng~ to the extractlon proce~6.
Flg. ~ 16 a 6chematlc flow dlagram showlng a further embodlment of the lnvention.
DETAILED DESCRIPTION OF THE INVENTION
Reference 16 made to Flgure 1 whlch lndlcate6 the manner ln whi~h pro~eEe w3ter le preeently ueed ln the extractlon ~3~?1692 proces6. AE can be 6een from the diagram, proceEE water enter6 the Eteam exchangerE through llne 11 ~or heat exchange purpoEeE and then pas6eE lnto the condltionlng drumE and then to the Eeparatlon cellE and the Ecavenger clrcult~. The waEte water talllngE from the Eeparatlon cellE (llne 13) and 6cavenger clrcultE (llne 15) 1E ~ed to a talllng~ EUmp ~rom whlch lt pa6EeE to a dlEtrlbutor whlch directE the water to the retentlon pond. The upper layer of water ln the talllng pond or rlver water 1E the Eource o~ proceEE water (llne 11) and Elnce thlE water 1E cold, usually from about 40 to about 65F., lt muEt be heated be~ore enterlng the condltlonlng drumE .
In the prOce6E o~ the lnventlon, however, aE 6hown ln Flgure 2, the waEte water i'rom the Ecavenger circuitE is fed through line 1~ to one or more ~locculating tank6. These tankE, usually cyllndrical, hold the waEte water while ~locculating agentE are added. U6e~ul agentE are any of the numerouE and well known i~locculating agentE, but a partlcularly preferred agent iE high molecular weight (4 to 6 mllllon) water soluble, anionic polyacrylamide whlch has about 26~ to about 36~ of ltE amlde grOupE hydrolyzed to carboxy groupE and, prei~erably, converted to the Eodlum Ealt.
ThlE polyacrylamlde ha~ been characteri2ed by Chemical AbEtractE under RegiEtry No. 37224-28-5 and iE commercially avallable ~rom Dow Chemlcal Company aE SEPARAN~ AP273 polymer ~Eee alEo U.S. 3,965,708 and BalakriEhnan et al., AICHE J. 21~6), 1225-7). Another pre~erred ~locculant iE
~3~?~6~12 PERCOLTM 1017 whlch ls a medlum hlgh molecular welght anlonlc flocculant available from Al11ed Colloids Company. Of co~rse, lt will be understood that injection of the flocculant in talllngs lines as well a~ other techniques may be used instead of direct addltlon to the flocculating tank.
The effect of the flocculant ls, of course, to effect a flocculatlon of the inorganlc sollds ln the waste w~ter. The flocculated inorganlc material settles to the bottom of the tank and ls taken to a talllngs sump, as shown, and then dlsposed to the dlstrlbutor for dlrectlon to the retentlon pond. The bitumen rlses to the top of the tank and ls taken through line 25 and combined with the bitumen froth from the Eeparatlon cells and Ecavenger circuits. The released water which rises to the top section of the tank is essentlally free o~ the sollds and ls recycled through llne 19, as shown, to the steam exchangers and then to the condltioning drums.
The taillngs water from the flocculating tank (llne 21) is taken to a tailings sump where it is comblned with the taillngs from the separatlon cells (llne 23).
Another embodlment o~ the lnventlon ls shown ln Flgure 3. As can be seen, ln thls procedure, the talllngs from the separatlon cells and the scavenger circuits (whole taillngs) are comblned and the combined tailings ln llne 29 are injected with flocculant and fed to the flocculating tank. Thls procdure provldes excellent mixing o~ the flocculant and better mixing of the sand from the separatlon cells and mlddllngs from the scavenger circults. Thls .. . , ,, ~, ~
13~ Z
technlque 1~ very CoEt efflclent ln that lt reduceE the capltal expenEe for plplng. It 1E de61rable to conEtruct the flocculatlng tank with two concentrlc welrE, the upper welr enabllng the bltumen froth to splll over for transport through llne 25, and the Eecond, lower welr belng uEed to collect the releaEed water for tran6port through llne lg.
A deElrable embodlment of the lnventlon 1~ to employ a plastlc or other Euitable veEEel a~ the flocculatlng tank whlch 1E floated ln the retentlon pond. The bltumen and releaEed water are Elmply pumped from the welrE at the top of the plaEtlc contalner and the Eettled 6011dE allowed to drop lnto the pond through the bottom of the veEEel.
The amount o~ flocculant whlch 16 added to the waEte talllngE need only be Eu~flclent to effect flocculatlon of the EolldE and, ln general, thlc wlll be doEageE from about 2.5 to about lOO ppm. It wlll be underEtood, o~ cour6e, that the actual doEage to be uEed wlll vary wlth the partlcular flocculant employed and wlth the partlcular characterlEtlcE
o~ the tallE, but Euch parameterE are readlly determined by the skllled art worker.
Preference for uEe o~ the SEPARANSM AD273 flocculant 1E
based on the fact that lt 1E extremely e~fectlve ln maklng a 6eparatlon o~ 6011dE ~rom the bltumen and water and, ln fact, thlE ~locculant can cauEe about 70~ or more o~ the bltumen ln the waEte water to float on the recovered water'6 Eur~ace.
The proceEE of the lnventlon provldeE numerouE benefltE whlch in~l~de a very hlgh recovery of the bltumen heretofore loEt 13(~16~Z
tD tail~. In addition, there iE reduced CoEt of pumping taillngE and recycle water and reduced Eludge accumulatlon and aEEoclated reclamatlon CoEtE. ThlE reEult~ from the flneE ln the bottom of the ~locculatlng tank entrapplng the Eand preEent and thlE effectlvely ellmlnate~ the formatlon of Eludge, thu~ maklng the waEte water more ea~lly tranEported and more envlronmentally acceptable. Stlll another ma~or advantage of the proceE6 1E the heat EavlngE obtalned from the UEe of the hot recycle water ~llne 19) fed to the extractlon EyEtem. Slnce thlE recycle water iE at a temperature between about 120 to about 140F., lt slgni~lcantly reduces the amount of Eteam needed to heat the addltional cold make-up water ~or the proceEE whlch comeE
~rom the talllngE pond or rlver.
The followlng Table llluEtrateE the bene~ltE obtalned ~rom the proceEE o~ the lnventlon. The Table 1E baEed on calculatlonE whlch 6how the ~avlngE obtalned over a ten-year perlod uEing preEent productlon level~ a6 a ba~e llne at a prlce of $20.00 (Cdn.) per barrel ~or bltumen.
~3C~16~Z
TABLE
ESTIMATED DOLLAR SAVINGS USING A FLOCCULATING TREATMENT
-FOR SCAVENGER TAILINGS IN AN OIL SANDS PROCESSING PLANT
X lo~
IncreaEed Bltumen Recovered: 252 Reduced C06t o~ Natural Gac ~or Steam and Boller~: 7 Reduced pumplng c06t6: 1 Total 260 Lec6 Flocculant C06t6: 2 Net Savlng~: 228
SANDS PROCESSING TO EFFECT PROCESS EFFICIENCIES
BACKGROUND OF THE I~VENTION
ThlE lnventlon relateE to an lmprovement ln the proce661ng of recycle water ~rom oll Eand6 operatlon6 whereln bltumen 16 recovered ~rom tar Eand6 whlch are EubEequently converted to petroleum product6.
In the hot water extractlon procesB of oll ~and6 (al~o known a6 tar Eand6) ln the northeaEt provlnce o~ Alberta, Canada, the extractlon method comprl6e6 three maJor proce6s 6tep6 plus a flnal extractlon u6ed to clean up the recovered bltumen ~or ~urther proce661ng. In the ~lr6t 6tep, called condltloning, oil 6and 16 mlxed with water snd heated with open steam to i'orm a pulp o~ 70-85 wt.~ 6011d6. Sodlum hydroxlde or other reagent6 are added a6 requlred to malntaln the pH ln the range o~ about 8.0-8.5. In the 6econd 6tep, called 6eparatlon, the condltloned pulp 16 dlluted ~urther with hot water 60 that separation can take place. The bulk o~ the sand-612ed particle6 ~greater than 325 me6h Ecreen) rapidly 6ettle6 and 16 wlthdrawn a6 6and talllng6. Mo6t o~
the bitumen rapldly float~ (6ettle6 upward) to i'orm a coherent ma66 known a~ bitumen froth whlch i6 recovered by 6klmmlng the 6eparation ve66el. An aqueou~ middllng6 layer containlng 60me mineral and bitumen i6 formed between the6e layerE. A ECavenger 6tep may be conducted ln the mlddllng6 ~$
13~16~2 layer ~rom the prlmary Eeparation Etep to recover addltlonal amountE o~ bltumen thereSrom and thls Etep usually comprl~eE
aeratlng the mlddllngs. The frothE recovered from the prlmary and the Ecavenger 6tep can be combined, dlluted wlth naphtha and centrl~uged to remove water and mlnerals. The naphtha 1E then dlstllled ~or further proceEElng. Hot water proceEEeE are deEcrlbed ln Canadian Patent NumberE B82,668;
866,226; 891,472; 892,548; and g73,500. TalllngE can be collected Srom the a~orementloned proceEslng Eteps and generally wlll contaln Eolld6 aE well a~ dlEEolved chemlcal6.
l'he talllngE are collected ln a retentlon pond ln whlch addltlonal 6eparatlon occurE. The talllng6 can alEo be consldered aE proceEElng water contalnlng EolldE whlch are dlEcharged ~rom the extractlon proceEE. The talllngE
comprlEe water, both the natural occurrlng water and added water, bltumen and mlneral.
Condltlonlng tar EandE Sor the recovery oS bltumen conElEtE oS heatlng the oll Eand/water mlxture to proceEE
temperature (180-200F.), phy61cally mlxlng the pulp to unlform compoEltlon and conEiEtency, and the conEumptlon ~by chemlcal reactlon~ oS the cauEtic or other added reagentE.
Under theEe condltlonE, bltumen 1E Etrlpped Srom the lndlvldual Eand gralns and mixed lnto the pulp ln the Sorm oS
dlEcrete dropletE o~ a partlcle Elze on the 6ame order aE
that oS the Eand graln6. ~urlng condltlonlng, a large fractlon of the clay partlcle6 become6 well dlEperEed and mlxed throughout the pulp. The condltlonlng procesE whlch 13~6~
prlepares bltumen for efflclent recovery durlng the following proceEE stepE alEo caUEeE the clayE to be the moEt dlfflcult to deal wlth ln the talllngE dl6poEal operatlon.
The other proceEE Etep, called ~eparatlon, 1 actually the bltumen recovery Etep, the Eeparatlon havlng already occurred durlng condltlonlng. The condltloned oll sand pulp 16 Ecreened to remove rock~ and uncondltlonable lumps of tar EandE and clay. The re~ect materlal, ~Ecreen overEize,~ is dlEcarded. The Ecreened pulp 1E further dlluted wlth water to promote two Eeparatlon proceEEes. Globules of bltumen, eE6entlally mlneral-free, float upward to form a coherent maEE of froth on the Eurface of the Eeparatlon unlt6; and, at the eame tlme, mlneral partlcleE, partlcularly the Eand Elze materlal, Eettle down and are removed ~rom the bottom of the Eeparatlon unlt aE OEand talllngE. TheEe two Eettllng procesEeE ta~e place through a medlum called the mlddllngE.
The mlddllngE conElEt prlmarlly of water, bltumen partlcle6, and Euepended flneE.
The partlcle ElzeE and denEltles of the Eand and of the bltumen partlcleE are relatlvely flxed. The parameter whlch ln~luenceOE the 6eparatlon proceEEeE moEt 1E the apparent vlEcoElty of the mlddllngE. CharacterlEtlcally, aE the EuEpended materlal content rlEeE above a certaln thre6hold, whlch varle~ accordlng to the compoEltlon of the EuEpended flneE, apparent vlEcoElty rapldly achleveE hlgh valueE wlth the ef~ect that the Eeparatlon proceE6eE eEEentlally Etop.
Llttle or no bltumen 1E recovered and all EtreamE exltlng the 13~16~Z
unit have about the 6ame compoeltlon 9E the ~eed. Ae the feed Eu6pended flneE content lncreaeee, more water muet be uEed ln the proceEE to malntaln mlddllng~ vlEcoElty wlthln the operable range.
The thlrd Etep of the hot water proceEE 1E ECaVen91n9 The feed of 6u~pended flneE content determlne~ the proce~
water requlrement through the need to control mlddllng6 vlEcoElty whlch, as noted before, 1E governed by the clay~water ratlo and the type o~ clay mineralE. It 16 uEually neceEEary to wlthdraw a drag Etream of mlddllngE to malntaln the Eeparatlon unlt materlal balance, and thlE
Etream o~ mlddllng& can be Ecavenged for recovery of lncremental amount6 o~ bltumen. Alr ~lotatlon 1~ an e~fectlve Ecavenglng method ~or thlE mlddllngE Etream.
Flnal extractlon or froth clean-up 1E UEUa11Y
accompllEhed by centrlfugatlon. Froth from prlmary extractlon le dlluted wlth naphtha, and the dlluted froth 1E
then 6ub~ected to a two Etage centrlfugatlon. Thl6 process yleldE an oll product of eEsentlally pure, but dlluted, bltumen. Water and mlneral and any unrecovered bltumen removed from the froth conEtltuteE an addltlonal talllng Etream whlch muEt be dlEpoEed.
In the termlnology o~ extractlve proceEElng, talllngE
are a throwaway materlal generated ln the cour6e of extractlng the valuable materlal from the non-valuable materlal. In oll ~andE proceEElng, talllngE con~lst of the whole oll Eand~ plu6 net addltlonE of proceEE water leEE only 13~316~Z
the recovered bltumen product. 011 ~and tall lngE can be 6ubdlvlded lnto three categorle6~ creen overElze;
~2) Eand talllngs--the fraction that EettleE rapldly, and (3) mlddllng~--the fractlon that settles slowly. Screen overElze 1~ typlcally collected and handled aE a ~eparate stream .
Talllngs dlsposal 1~ the operatlon regulred to place the talllngE ln a flnal reEtlng place. ~ecauce the tailings contaln bltumen emulElon6, flnely dlEperEed clay wlth poor Eettllng characterlEtlcE and other contamlnantE, water pollutlon conElderatlons prohlblt dlEcardlng the talllngs into rlvers, lakeE, or other natural bodieE. Currently, the talllngE are ~tored in retentlon pondc whlch lnvolve large 6pace requlrementE and the conEtructlon of expenslve encloEure dlkeE. A portlon o~ the clear water layer at the top o~ the talllnq6 pond may be recycled back lnto the water extractlon proceEE a6 an economlc mea6ure to con6erve water.
Currently, two maln operatlng mode6 ~or talllng6 dl6posal are: ~1) dlke bulldlng--hydraullc conveylng of taillng6 followed by mechanlcal compactlon of the 6and talllngs fractlon; and (2) overboardlng--hydraullc tran6port wlth no mechanlcal compactlon.
The pre6ent lnventlon 16 dlrected to the water ln the talllngE from the 6eparatlon cellE and/or the 6cavenglng clrcultE whlch, ln accord wlth the lnventlon, 16 recycled back lnto the water extractlon proceEs and provldeE for i~proved proceEE e~flclencleE and lmproved proces6 economlc6.
13~169Z
~UMMARY OF THE INVENTION
The proceE6 of the lnventlon lnvolveE flocculating the dl6charge from the 6eparatlon cellE and/or the scavenger clrcults employed ln the oll Eands proce~sing and returning to the condltloning drumE and Eeparatlon cells water recovered from the flocculated talllngE. As a result of the proce6~ of the lnventlon, water conEervatlon, energy 6avlngs, lncrea6ed bltumen recovery, and other beneflt6, a6 wlll be detalled later, are obtalned.
DESCRIPTION OF THE DRAWINGS
Flg. 1 16 a 6chematlc flow dlagram of water uEe ln the ol1 sand6 extractlon proce6s as presently practlced.
Flg. 2 16 a echematlc flow dlagram 6howlng the flocculatlng 6tep of the lnventlon and recycle of the water from the flocculated talllng~ to the extractlon proce~6.
Flg. ~ 16 a 6chematlc flow dlagram showlng a further embodlment of the lnvention.
DETAILED DESCRIPTION OF THE INVENTION
Reference 16 made to Flgure 1 whlch lndlcate6 the manner ln whi~h pro~eEe w3ter le preeently ueed ln the extractlon ~3~?1692 proces6. AE can be 6een from the diagram, proceEE water enter6 the Eteam exchangerE through llne 11 ~or heat exchange purpoEeE and then pas6eE lnto the condltionlng drumE and then to the Eeparatlon cellE and the Ecavenger clrcult~. The waEte water talllngE from the Eeparatlon cellE (llne 13) and 6cavenger clrcultE (llne 15) 1E ~ed to a talllng~ EUmp ~rom whlch lt pa6EeE to a dlEtrlbutor whlch directE the water to the retentlon pond. The upper layer of water ln the talllng pond or rlver water 1E the Eource o~ proceEE water (llne 11) and Elnce thlE water 1E cold, usually from about 40 to about 65F., lt muEt be heated be~ore enterlng the condltlonlng drumE .
In the prOce6E o~ the lnventlon, however, aE 6hown ln Flgure 2, the waEte water i'rom the Ecavenger circuitE is fed through line 1~ to one or more ~locculating tank6. These tankE, usually cyllndrical, hold the waEte water while ~locculating agentE are added. U6e~ul agentE are any of the numerouE and well known i~locculating agentE, but a partlcularly preferred agent iE high molecular weight (4 to 6 mllllon) water soluble, anionic polyacrylamide whlch has about 26~ to about 36~ of ltE amlde grOupE hydrolyzed to carboxy groupE and, prei~erably, converted to the Eodlum Ealt.
ThlE polyacrylamlde ha~ been characteri2ed by Chemical AbEtractE under RegiEtry No. 37224-28-5 and iE commercially avallable ~rom Dow Chemlcal Company aE SEPARAN~ AP273 polymer ~Eee alEo U.S. 3,965,708 and BalakriEhnan et al., AICHE J. 21~6), 1225-7). Another pre~erred ~locculant iE
~3~?~6~12 PERCOLTM 1017 whlch ls a medlum hlgh molecular welght anlonlc flocculant available from Al11ed Colloids Company. Of co~rse, lt will be understood that injection of the flocculant in talllngs lines as well a~ other techniques may be used instead of direct addltlon to the flocculating tank.
The effect of the flocculant ls, of course, to effect a flocculatlon of the inorganlc sollds ln the waste w~ter. The flocculated inorganlc material settles to the bottom of the tank and ls taken to a talllngs sump, as shown, and then dlsposed to the dlstrlbutor for dlrectlon to the retentlon pond. The bitumen rlses to the top of the tank and ls taken through line 25 and combined with the bitumen froth from the Eeparatlon cells and Ecavenger circuits. The released water which rises to the top section of the tank is essentlally free o~ the sollds and ls recycled through llne 19, as shown, to the steam exchangers and then to the condltioning drums.
The taillngs water from the flocculating tank (llne 21) is taken to a tailings sump where it is comblned with the taillngs from the separatlon cells (llne 23).
Another embodlment o~ the lnventlon ls shown ln Flgure 3. As can be seen, ln thls procedure, the talllngs from the separatlon cells and the scavenger circuits (whole taillngs) are comblned and the combined tailings ln llne 29 are injected with flocculant and fed to the flocculating tank. Thls procdure provldes excellent mixing o~ the flocculant and better mixing of the sand from the separatlon cells and mlddllngs from the scavenger circults. Thls .. . , ,, ~, ~
13~ Z
technlque 1~ very CoEt efflclent ln that lt reduceE the capltal expenEe for plplng. It 1E de61rable to conEtruct the flocculatlng tank with two concentrlc welrE, the upper welr enabllng the bltumen froth to splll over for transport through llne 25, and the Eecond, lower welr belng uEed to collect the releaEed water for tran6port through llne lg.
A deElrable embodlment of the lnventlon 1~ to employ a plastlc or other Euitable veEEel a~ the flocculatlng tank whlch 1E floated ln the retentlon pond. The bltumen and releaEed water are Elmply pumped from the welrE at the top of the plaEtlc contalner and the Eettled 6011dE allowed to drop lnto the pond through the bottom of the veEEel.
The amount o~ flocculant whlch 16 added to the waEte talllngE need only be Eu~flclent to effect flocculatlon of the EolldE and, ln general, thlc wlll be doEageE from about 2.5 to about lOO ppm. It wlll be underEtood, o~ cour6e, that the actual doEage to be uEed wlll vary wlth the partlcular flocculant employed and wlth the partlcular characterlEtlcE
o~ the tallE, but Euch parameterE are readlly determined by the skllled art worker.
Preference for uEe o~ the SEPARANSM AD273 flocculant 1E
based on the fact that lt 1E extremely e~fectlve ln maklng a 6eparatlon o~ 6011dE ~rom the bltumen and water and, ln fact, thlE ~locculant can cauEe about 70~ or more o~ the bltumen ln the waEte water to float on the recovered water'6 Eur~ace.
The proceEE of the lnventlon provldeE numerouE benefltE whlch in~l~de a very hlgh recovery of the bltumen heretofore loEt 13(~16~Z
tD tail~. In addition, there iE reduced CoEt of pumping taillngE and recycle water and reduced Eludge accumulatlon and aEEoclated reclamatlon CoEtE. ThlE reEult~ from the flneE ln the bottom of the ~locculatlng tank entrapplng the Eand preEent and thlE effectlvely ellmlnate~ the formatlon of Eludge, thu~ maklng the waEte water more ea~lly tranEported and more envlronmentally acceptable. Stlll another ma~or advantage of the proceE6 1E the heat EavlngE obtalned from the UEe of the hot recycle water ~llne 19) fed to the extractlon EyEtem. Slnce thlE recycle water iE at a temperature between about 120 to about 140F., lt slgni~lcantly reduces the amount of Eteam needed to heat the addltional cold make-up water ~or the proceEE whlch comeE
~rom the talllngE pond or rlver.
The followlng Table llluEtrateE the bene~ltE obtalned ~rom the proceEE o~ the lnventlon. The Table 1E baEed on calculatlonE whlch 6how the ~avlngE obtalned over a ten-year perlod uEing preEent productlon level~ a6 a ba~e llne at a prlce of $20.00 (Cdn.) per barrel ~or bltumen.
~3C~16~Z
TABLE
ESTIMATED DOLLAR SAVINGS USING A FLOCCULATING TREATMENT
-FOR SCAVENGER TAILINGS IN AN OIL SANDS PROCESSING PLANT
X lo~
IncreaEed Bltumen Recovered: 252 Reduced C06t o~ Natural Gac ~or Steam and Boller~: 7 Reduced pumplng c06t6: 1 Total 260 Lec6 Flocculant C06t6: 2 Net Savlng~: 228
Claims (10)
- Claim 1. In the process of recovering bitumen from oil sands wherein the oil sands are subjected to a hot water extraction comprising the steps of conditioning the oil sands, settling the conditioned oil sands in separation cells and subjecting the middlings layer to a scavenging step, the improvement of flocculating the inorganic material in the discharge from the separation cells and/or the scavenger circuits and recycling the released water to the conditioning step.
- Claim 2. The process of Claim 1 wherein the discharge from the scavenging circuits is flocculated.
- Claim 3. The process of Claim 2 wherein the flocculant employed is a high molecular weight (4 to 6 million) water soluble, anionic polyacrylamide which has about 26% to about 36% of its amide groups hydrolyzed to carboxy groups.
- Claim 4. The process of Claim 3 wherein the flocculant is employed at a dosage of from about 2.5 to about 100 ppm.
- Claim 5. In the process of recovering bitumen from oil sands wherein the oil sands are subjected to a hot water extraction comprising the steps of conditioning the oil sands, settling the conditioned oil sands in separation cells and subjecting the middlings layer to a scavenging step, the improvement of flocculating the inorganic matter in the combined discharge from the separation cells and scavenger circuits and recycling the released water to the conditioning step.
- Claim 6. The process of Claim 5 wherein the flocculating agent is employed in an amount of from about 2.5 to 100 ppm.
- Claim 7. The process of Claims 5 or 6 wherein the flocculant is a high molecular weight (4 to 6 million) water soluble, anionic polyacrylamide which has about 26% to about 36% of its amide groups hydrolyzed to carboxy groups.
- Claim 8. The process of Claim 7 wherein flocculant is in the form of sodium salt.
- Claim 9. The process of Claims 1, 2, 3, 4, 5, 6 or 8 wherein the flocculant is the polyacrylamide characterized by Chemical Abstracts Registry No. 37224-28-5.
- Claim 10. The process of Claims 1, 2, 3, 4, 5, 6 or 8 wherein the flocculation is made to occur in a tank floating in a retention pond for waste tailings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000559659A CA1301692C (en) | 1988-02-24 | 1988-02-24 | Process for flocculating recycle water from oil sands processing to effect efficiencies |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000559659A CA1301692C (en) | 1988-02-24 | 1988-02-24 | Process for flocculating recycle water from oil sands processing to effect efficiencies |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1301692C true CA1301692C (en) | 1992-05-26 |
Family
ID=4137504
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000559659A Expired - Lifetime CA1301692C (en) | 1988-02-24 | 1988-02-24 | Process for flocculating recycle water from oil sands processing to effect efficiencies |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1301692C (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7914670B2 (en) | 2004-01-09 | 2011-03-29 | Suncor Energy Inc. | Bituminous froth inline steam injection processing |
| US9068776B2 (en) | 2009-10-30 | 2015-06-30 | Suncor Energy Inc. | Depositing and farming methods for drying oil sand mature fine tailings |
| US9404686B2 (en) | 2009-09-15 | 2016-08-02 | Suncor Energy Inc. | Process for dying oil sand mature fine tailings |
| US9909070B2 (en) | 2009-09-15 | 2018-03-06 | Suncor Energy Inc. | Process for flocculating and dewatering oil sand mature fine tailings |
-
1988
- 1988-02-24 CA CA000559659A patent/CA1301692C/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7914670B2 (en) | 2004-01-09 | 2011-03-29 | Suncor Energy Inc. | Bituminous froth inline steam injection processing |
| US8685210B2 (en) | 2004-01-09 | 2014-04-01 | Suncor Energy Inc. | Bituminous froth inline steam injection processing |
| US9404686B2 (en) | 2009-09-15 | 2016-08-02 | Suncor Energy Inc. | Process for dying oil sand mature fine tailings |
| US9909070B2 (en) | 2009-09-15 | 2018-03-06 | Suncor Energy Inc. | Process for flocculating and dewatering oil sand mature fine tailings |
| US10590347B2 (en) | 2009-09-15 | 2020-03-17 | Suncor Energy Inc. | Process for flocculating and dewatering oil sand mature fine tailings |
| US9068776B2 (en) | 2009-10-30 | 2015-06-30 | Suncor Energy Inc. | Depositing and farming methods for drying oil sand mature fine tailings |
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