Water Treatment and Reuse in Oil Sands Development
PI: Andy Hong, Ph.D., P.E., Professor Presented by: Zhixiong Cha, Ph.D. Student (A. Hong on sabbatical)
Work In-Progress Presented today: • Treatment of Produced Water • Extraction of Bitumen from Oil Sands – New Technology Additional task in progress: • Removal of naphthenic contaminants
Technologies & Rights • Heightened Ozonation Treatment (HOT) – U-3996; PCT filed • Heightened Oil Sand Extraction (HOSE) – U-4313; PCT filed University of Utah is IP owner and licensor of all technologies.
Heightened Ozonation Treatment (HOT) with Compression and Decompression Cycles (University of Utah Patent Pending—Contact Technology Transfer Office)
Heightened Ozonation Treatment (HOT) -Microbubbles of O3 in Oil/Sheen Removal Combine flotation with O3 treatment Remove dispersed oil by flotation Chemically convert dispersed oil for removal via emulsification, coagulation, coarse filtration Chemically convert dissolved, trace oil into acids, preventing sheen formation Rapid, cost-effective, wide operating conditions
Microbubbles at decompression
Other Related Technologies for Produced Water Treatment •
Microbubble floatation - dispersed oil removal – Achievements: > 95% removal of oil; remove oil droplet > 3 microns – Drawbacks: microbubbles are mechanically generated (injection and turbulence), cannot totally prevent oil sheen
•
Micro ozone/air bubble treatment – dissolved oil treatment (Oak Ridge National Laboratory ) – Achievement: accelerates degradation of hydrocarbons in the aqueous phase – Drawbacks: fouling of the electrostatic sprayer; not effective for high-salinity water
Synthetic Produced Water (SPW) and Real Produced Water (RPW) 14000
SPW -- prepared by mechanically mixing Rangely crude oil with water.
Number (n/L)
12000 10000 8000 6000 4000 2000 0 0
10
20
30
40
50
Oil droplet size (micron)
Size distribution (as #/L) of oil droplets according to size in SPW.
Treated RPW
RPW RPW -- from Conoco Phillips, Inc. TOC = 370 mg/L, SOC = 155 mg/L.
60
GC/MS Analyses of Hexane-Extractable Hydrocarbons Dissolved in SPW and RPW Abundance
Phenol, 2,4-bis[1,1-dimethylethyl]-
Diethylene glycol dibenzoat
TIC: cha0119oil.D
1300000
2-Tetradecene
1200000 1100000
Hexane-extractable hydrocarbons in SPW
1-Octadecene
1000000
2-Tetradecene
900000
1-Nonadecene
800000 700000 600000 500000
1-Docosen
1-Decene
400000 300000 200000 100000
5.00
10.00
15.00
20.00
25.00
30.00
35.00
40.00
45.00
Time-->
Phenol,2,4-bis[1,1dimethylethyl]E-15-Heptadecenal 1-Tetradecene 1-Dodecene
1-Docosene
1-Hexadecene 5-Eicosene,[E]-
Morphline,4phenyl-
Hexane-extractable hydrocarbons in RPW
Ozonation Results for SPW Purpose
Sample COD Treatment method (mg/L)
Solid floated (COD mg/L)
Solid filtered (COD mg/L)
COD after vacuum filtration, (mg/L)
78
No treatment
0
35
36
Micro bubble floatation effects on different size oil droplets
97
CDC air, (10 cycles)
45
10
31
97
Ordinary air, (10 minutes)
0
58
37
10 cycles CDC ozonation effects on different COD water
91
CDC ozone
0
40
52
320
CDC ozone
195
75
42
95
Ordinary ozone
22
30
39
245
Ordinary ozone
130
60
39
97
CDC ozone
0
32
64
320
CDC ozone
210
30
70
50 minutes ordinary ozonation effects on different COD water
282
Ordinary ozone
163
70
43
Ozonation with H2O2
293
CDC ozone/ H2O2 , (10 cycles)
148
85
56
Ozonation under basic condition
329
CDC ozone/pH=11, (10 cycles)
20
236
70
10 minutes ordinary ozonation effects on different COD water 50 CDC cycles ozonation effects on different COD water
a. CDC (compression/decompression); b. 1 cycle takes 1 minute.
Hydrophilic Products from SPW & Effects of Salinity COD after ozonation / 50 cycles COD after fltration / 50 cycles COD after ozonation 20 cycles COD after fltration / 20 cycles
140 120 COD (mg/L)
100 80 60 40 20 0 1
10
100
1000
10000
Salt Concentration (mg/L)
• •
Pressure-assisted ozonation of SPW generates hydrophilic organics Hydrophilic organics increase with increasing ozonation cycles while COD decreases.
• High salt content (high ionic strength) enhanced coagulation/deposition, improving oil removal
Ozonation Results For RPW Method
COD after treatment (mg/L)
COD after COD after additional filtration treatment (mg/l) (mg/l)
Without treatment
1035
789
10 CDC aeration + vacuum filtration
880
610
Sand Filtration
1043
730
10 CDC ozone + vacuum filtration
700
546
40 CDC ozone + vacuum filtration
594
512
10 CDC ozone + sand filtration+30 CDC ozonation + sand filtration 40 CDC ozone + sand filtration
708
598
588
535
RPW
10 CDC and 40 CDC and filtration filtration
RPW
428
Sand filtration
COD after filtration (mg/l)
420
10 CDC and sand filtration
Solvent-Extractable Products in Treated SPW and RPW Mass chromatogram of partially degraded hydrocarbons in SPW.
intermediates
Mass chromatogram after more cycles of CDC ozonation.
GC/MS Analyses of the Hydrophilic Products in SPW and RPW Abundance TIC: 0903 a 40.D Signal: 0903 a 40.D\ECD1A.CH
1600000
40 cycles SPW, hydrophilic compounds originated from dispersed hydrocarbons
1500000 1400000 1300000 1200000 1100000 1000000 900000 800000 700000 600000 500000 400000 300000 200000 100000 0 4.00
6.00
Some identified organics: 1,3-Dioxolane-4methanol,2,2-dimetnyl-,[s]-; Hexadecanoic acid, methyl ester; Propanoic,2-methyl-,butyl ester; Methyl 2-tetradecycloxiranecarboxylate; 2Acetylbenzoic acid; 2-Propenoic, 3-[4hydroxyphenyl],methyl ester; 2Naphthalenamine,5,6,7,8-tetrahydro-, 1-[2,3,4,5Tetramethylphenyl]ehtanone; 2-Hydroxy-2,4,4trimethyl-3-[3-methylbuta-1,3-dien], Naphtho[2,3b]thiophene; Dienzothiophene, 4-methyl-; 9HFluoren-ol,9-butyl-; Dibenzothiophene,4-methyl; [1,1’-Biphenyl]-2,2’-dicarboxaldehyde; 2,8Dimethylethyldibenzo[b,d]thiophene; Fluorenone oxime; Dibenzothiophene sulfone.
8.00 10.00 12.00 14.00 16.00 18.00 20.00 22.00 24.00 26.00 28.00
Time-->
40 cycles RPW, hydrophilic compounds originated from the dissolved hydrocarbons.
Some identified compounds are: 3.622 min, Thiazole,tetrahydro-; 5.720 min, Cyclopentylcarboxylic acid; 6.926 min, Cyclopentaneacetic acid; 7.114 min, Cyclohexanecarboxylic acid; 8.132 min, Cyclohexanecarboxylic acid, 4-methyl-; 9.606 min, 2-Butyl-3,4,5,6-tetrahydropyridine; 9.812 min, Cyclohexane, 1-methyl-2-pentyl.
Prevention of Oil Sheen Observations: • Ordinary bubbling ozonation or aeration (even with compressioncompression cycles does not prevent oil sheen formation • Once ozone contact the oil droplets, it changes surface properties and viscosity, resulting in coalescing of droplets and spreading of oil • Ozonation products as dissolved hydrophilic acids does not form sheen
Evaluation by Visual Inspection -- The thickness of oil sheen can be estimated based on the following table. The removal of oil sheen is evaluated by visual inspection.
O il type
A ppearance
O il sheen O il sheen
Silver Iridescent (rainbow ) B row n to B lack B row n/O range
C rude and Fuel O il W ater-in-oil E m ulsions
A pproxim ate T hickness >0.0001 m m >0.0003 m m
A pproxim ate V olum e (m 3 /km 2 ) 0.1 0.3
>0.1 m m
100
> 1 mm
1000
Design of HOT Process for Produced Water 1. 2. 3.
Brief ozonation cycles to promote coagulation of dispersed oil and removal via flotation Coarse filtration to remove coagulated oil More ozonation cycles to convert dissolved oil into organic acids and biodegradable products, preventing sheen formation
P-8
Venting
Venting P-7
Pretreated water Produced water
P-12
Ozonation reactor
Ozonation reactor
P-9 P-18
E-4
Filter
E-1
Ozone
Ozone Generator
P-15
P-14
E-2
P-2 P-17
P-3
E-6
Gas Compressor
Treated water
E-3 E-5
Water pump Oil P-4 P-11
P-4
Ozone
Summary
• Ozonation with pressure cycles coagulate dispersed oil and remove oil by flotation • Ozone converts dissolved oil into highly soluble organic acids that are more biodegrdable, eliminating the potential to form sheen • Pressure cycles provide abundant gas-liquid interface as reactive zone for ozone and hydrophobic compounds to react
Conventional Hot Water Extraction of Bitumen form Oil Sands Hot water process consists of two steps: separation and recovery of bitumen. Disadvantages: • < 75% bitumen are recovered from oil sands • Caustic reagents and other additives are needed • Generation of tailings Recently efforts have been on reducing process costs by reducing the slurry temperature, with increased uses of additives and co-solvents
Heightened Oil Sands Extraction (HOSE) with Pressure Cycles (U-4313) •
• • •
• • •
1) Higher product yield – penetration of dissolved air into small spaces of deposit particles during compression; subsequent decompression results in gaseous micro bubbles expanding within the mineral particle, prying open the sands to expose the bitumen deposited within thus enhancing recovery. 2) Easier product separation – decompression results in countless micro bubbles that provide a huge area at the gas-liquid interface that attracts and gathers hydrophobic bitumen, effectively separating and lifting the bitumen globs to the water surface for collection (i.e., the flotation effect). 3) Energy saving – due to enhanced bitumen exposure, lower water temperature can be used for higher yield, which results in energy saving that more than compensates the minimal energy expended in compression with air. 4) Shorter process time – the new process with rapid pressure cycles cuts down contact time of tar sands by hot water. Our preliminary results show > 90% yield of bitumen within 20 min, in comparison to extraction without the pressure cycles that requires 3 hours of contact with hot water and under intense agitation. 5) Less materials and energy – the new process requires no agitation or addition of caustics that are often used with conventional extraction [and potentially little agitation]. 6) Higher throughput – the extracted sands show excellent settling characteristics requiring no elaborate, time-consuming separation equipment and process. 7) Application for indigenous tar sands – the new process has been preliminarily tested and found to be equally suited for Utah’s tar sands that are oil wet; unlike Canadian’s water wet oil sands, the oil wet property is an impediment to effective recovery by conventional hot water extraction method. Thus, this is a new tool central to developing Utah’s unique, rich tar sands resources.
Bitumen Extraction with Pressure Cycles
Asphalt Ridge oil sands, Utah, containing 12±1.7% bitumen by wt.
HOSE process Depleted and settled oil sands (left) Extracted, separated bitumen (right) Conditions: T = 85 oC; P = 100 psi; 20 cycles Total extraction time: 10 min
Extraction with Pressure Cycle of Air (solid/water ratio varied)
Recovered bitumen (wt%
100 90 80 70 60 solid:water=0.5:1 solid:water=1:1 solid:water=1.5:1
50 40 30 20 10 0 0
2
4 Cycle number
6
8
Extraction with Pressure Cycle of Air (P = 150 psi) 100
Recovered bitumen (%)
90 80
Overheated
70
95 degree
60
85 degree 75 degree
50
65 degree
40 30 20 10 0 0
5
10
15
20
Cycle
Solid to Water Ratio = 0.5:1 (v/v)
25
Extraction with Pressure Cycle of Air 100
90
90
80
80
Extracted bitumen (%)
Recoveed bitumen (%)
100
70 Overheated 95 degree 85 degree 75 degree 65 degree
60 50 40 30 20
50 40 30 20
0
0 10
15
20
25
85 degree
60
10 5
95 degree
70
10 0
Overheated
0
5
10
15 Cycle
Cycle
Solid to Water Ratio = 0.5:1 (v/v)
20
25
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