Ceramic Membranes for the Oilfield Produced Water Treatment Figure 2: Schematic Diagram of the Laboratory-scale Multistage Cross-flow Filtration System Concentrate recovery/disposal Retentate F F T Valve Permeate P MF Air Source feed T pt100 F P Source feed
Barometer P
Air P UF Air P NF US
Ultrasonic transducer
Flowmeter F F F P F P F P
P
Cleaning solution
Heater
Pump
Automation and process control system
Table 1: Material and Properties of the Ceramic Membranes Used in This Investigation
Membrane MF Al2O3 Material
Al2O3
Cut-off pH °C
UF TiO2 TiO2/Al2O3
0–14 121
NF TiO2 TiO2 /TiO2
0.1μm/0.2μm 0.05μm/20kDa 1,000Da 0–14 121
0–14 150
MF = microfiltration; NF = nanofiltration; UF = ultrafiltration. Table 2: Summary of the Results
Variation Range of Feed Quality Oil (mg/l) TOC (mg/l)
Salinity (mg/l) EC (µS/cm)
Salinity (mg/l)
Variation Range of Process Parameter CFV (m/s) TMP (bar)
Temperature (°C)
Cleaning Strategies Single
Combined
Process Configurations Single
Combined
Results: Total Reduction Oil-removal TOC-removal
10–5,500 200–2,000 10–2,500
20,000–80,000 10–2,500
0.6–1.3 0.5–2 20–80
Chemical, BF Chemical/BF, chemical/US, BF/US MF, UF, NF MF/UF, UF/NF, MF/UF/NF
>99.5% >70.0%
BF = back flushing; EC = electric conductivity; MF = microfiltration; UF = ultrafiltration; NF = nanofiltration; TOC = total organic carbon; US = ultrasound.
Meanwhile, a variety of multichannel geometries is used by the industry. The outer diameter of the membrane elements and the number and diameter of channels is selected depending on the application. Ceramic membrane elements range from an outer diameter of 10mm and up to seven channels for laboratory and test purposes to membrane elements with an outer diameter of 52mm and 19 or more channels for filtering purposes on a large industrial scale. Ceramic membranes are available with in–out and out–in flow directions. In–out membranes
100 NF TiO2
TiO2 /Al2O3 750Da
0–14 120
These characteristics indicate that ceramic membranes could replace their organic polymeric counterparts in many applications where the conditions would otherwise preclude using an organic polymer membrane. The use of ceramic membranes for the treatment of wastewaters is growing in certain applications; above all in those filtration processes where polymeric membranes cannot be applied.
Ceramic membranes also present some disadvantages. All of these are related to their relatively high cost because of the expensive raw materials, fabrication of a complex multilayer system and low membrane surface area.2
to five times higher than polymeric membranes)11,12 by their higher permeability and longer lifetime.
Ceramic Membranes for the Treatment of Oilfield Produced Water
Ceramic membranes have attracted interest due to their superior mechanical, thermal and chemical stability. The primary advantage of using ceramic membranes is the ability to accomplish current and pending regulatory treatment objectives with no chemical pre-treatment.
The ceramic membrane filtration technique can remove organic molecules, such as oil and grease, dissolved hydrocarbons, proteins, colloidal particles and micro-organisms. It can tolerate high variation in concentrations of suspended solids, oil and grease in produced water.
EXPLORATION & PRODUCTION – VOLUME 9 ISSUE 1
The high cost of ceramic membranes (three is compensated for
Ceramic membranes preserve their properties when heated to 1,000°C and higher and can operate at high pressures (1–10bar). They can be periodically subjected to steam sterilisation at 120°C or calcination for burning contaminating agents at 500°C. They have a wide pH range, are reliable and have a long service life without deformation. The size of their pores can be controlled easily. They are highly permeable and possess the requisite strength; the latter is provided by the macroporous base (substrate).11
are produced as monolith or element type; out–in membranes as flat sheet type.
Backflush vessel
Backflush vessel
Backflush vessel
Ultrasonic processor
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