Oil-Sands Produced Water Treatment

by Electrocoagulation

Edward P.L. RobertsDr. Nael Yasri & Dr. Michael Nightingale

Tianpei Shu, Behzad FuladpanjehDr. Thomas Oldenburg

Dr. Milana TrifkovicDr. Bernhard Mayer

1

Outline

Introduction Electrocoagulation Produced water treatment

EC performance ChallengesComplexityElectrode fouling FoamingpH distribution

Conclusions

2

Introduction - Elecrocoagulation

3

Applications:Produced water

TailingsPulp & paper

Mechansims:in-situ studies

LSCMRaman

Innovation & Design:

Polarity reversalOscillation

Magnetic field

Introduction – Produced water

4

Produced Water Treatment Silica removal Hardness, organics (dispersed /dissolved), sulfides

Res

ervo

ir

Oil water separation

Lime softening

oil sludgesteam

OTS

G

Disposal

EC ECEC

ECEC

5

Produced Water Composition

Our sample!

6

Produced Water Composition

TOC: 200-500 mg/L Dissolved Si: 50-70 mg/L

EC Performance

7

Si Removal in Synthetic & Real Water

8

Much larger charge required to remove Si from real water Lower charge required to remove Si using Al v’s Fe

0%10%20%30%40%50%60%70%80%90%

100%

0 500 1000 1500 2000 2500 3000

Conc

entr

atio

n

Charge Loading C/L

Syn Fe

RW Fe

RW Al

Produced Water - Organics

9

Ultra high resolution mass spectrometry

Challenges: Foaming

10

Treated with Al electrodes2500 C/L

Treated with Fe electrodes2500 C/L

Challenges: Electrode Fouling

0 20 40 60 80 100 12040

50

60

70

80

90

100

Mild steel electrode

Fouling starts after 76 min

J/ A

m-2

Time/ min

Fouling occur after 104 min

After treatment Bare Fe electrde

0 500 1000 1500 2000 2500 3000 3500 4000

530

540

550

560

570

580

590

600

Black fouling

SO2-4

5

6

1 4231

6 = Si5 = Fe2O3

4 = Fe3O4

3 = FeS2 = polysulfide SnS

2-1 = S8

Wavenumber (cm-1)

Inten

sity (

a.u.)

Challenges: Electrode fouling

Ex-situ Raman Spectra of fouling layer

13

Challenges: pH distribution

Laser Scanning Confocal Microscopy

Effective Si Removal Sulfide + some hardness

BUT:Real Water Complexity:

Variability Stability Organics

EC Process complexity pH, speciation, transport …

Other challenges Electrode fouling Foaming

14

CONCLUSIONS

Acknowledgement

15