Electrochemical Technologies for Removing Petroleum Hydrocarbons from Produced Water
chemicals (production treating, gas processing, stimulation); and production treating chemicals (scale and corrosion inhibitors, biocides, emulsion breakers, antifoam and water treatment chemicals);
•
production solids (including formation solids, corrosion and scale products, bacteria, waxes and asphaltenes); and
• dissolved gases.6
and the presence of dissolved and suspended oil in produced water (prior to treatment) depends on several factors.1,6
Impact of Produced Water Discharge
Produced water from the oil and gas industries is often allowed to be discharged into the environment. Toxicity and organic loading generally characterise the impact of discharging produced water into the sea. The effects of produced water components on the environment are:1
• increase in the salinity; • • •
dispersed and soluble oil contribution in marine ecosystems; inclusion of other compounds from treating chemicals; higher concentration of heavy metals than in seawater; and
• presence of radionuclides. Treatment of Produced Water
To meet environmental regulations as well as facilitate the recycling and re-use of produced water, many researchers have focused on
Membrane treatments
Water cannot dissolve all hydrocarbons, so most of the oil is dispersed in water;4
Produced water treatment processes
Figure 1: Main Methods Used for the Removal of Pollutants from Produced Water, Including Electrochemical Processes
Physical treatments
Adsorption of dissolved organics on activated carbon, organoclay, copolymers, zeolite, resins • Sand filters • Cyclones • Evaporation
• Dissolved air precipitation • CTour process • Freeze–thaw/evaporation • Electrodialysis
Chemical treatments
• Chemical precipitation • Chemical oxidation
• Room temperature ionic liquids • Demulsifiers
Biological treatments
• Mixed cultures • Aerobic decomposition • Anaerobic decomposition
• Microfiltration, ultrafiltration, nanofiltration and reverse osmosis
• Bentonite clay and zeolite membrane • Combined systems
• Modified membrane systems to reduce fouling
Advanced oxidation processes
• Electrochemical processes • Photocatalytic treatment • Fenton process • Treatment with ozone
• Electrocoagulation • Electroflotation • Electro-oxidation • Indirect electro-oxidation with strong oxidants
treating oily saline produced water. Oil content and salinity of produced water from offshore and onshore activities can be reduced through various physical, chemical and biological methods. In offshore extraction facilities, due to space constraints, compact physical and chemical treatment technologies are preferred.
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98 |
Page 99 |
Page 100 |
Page 101 |
Page 102 |
Page 103 |
Page 104 |
Page 105 |
Page 106 |
Page 107 |
Page 108 |
Page 109 |
Page 110 |
Page 111 |
Page 112 |
Page 113 |
Page 114 |
Page 115 |
Page 116 |
Page 117 |
Page 118 |
Page 119 |
Page 120 |
Page 121 |
Page 122 |
Page 123 |
Page 124