Leiknes_subbed.qxp 30/3/09 09:24 Page 112
Cleaning Efficiency of Biodegradable Products on Fouled Ceramic Membranes by Analogue Produced Water
Figure 4: Total Cleaning at 80ºC with Different Transmembrane Pressures
of flux recovery. From Figure 4, it can be seen that at a high
temperature (80ºC; cleaning numbers 1–4) the total recovery for two-
1.2
step cleaning is quite good, except for the 0.5µm pore size. This could
possibly be due to pore plugging by colloidal material and the high
1.0
TMP during cleaning, which could compact the foulant into the
membrane pores and thus give a lower flux recovery. The sensitivity of
0.8
TMP during cleaning was tested by combining the low efficient
cleaning acid/alkaline agent (SurfactronCD50 1%vol/Ultrasil 115
0.6
1%vol) option. Reducing the TMP from 0.85±0.1 to 0.25±0.1 bar
Flux recovery
showed a significant effect and gave a higher total flux recovery.
0.4
Membrane Retention in Total Cleaning
0.2
Besides the assessment of cleaning efficiency, membrane retention was
0.0
also recorded from several cleaning sequences. The purpose was to
123411
ensure that the chemical cleaning agent used did not change or
Cleaning number
0.5µm 0.2µm 0.1µm
damage the membrane surface or membrane separation properties.
After a cleaning cycle was completed, membrane filtration of
Table 3: Flux Recovery – All Cleaning Tests
the analogue PW was continued, with the total hydrocarbon in the
No. of
permeate being measured. Table 4 shows that the total hydrocarbon
Cleaning Test Flux Recovery
concentrations measured in the permeate were more or less the same
0.1µm 0.2µm 0.5µm
for all cleaning sequences tested. This implies that application of the
1 0.98 0.99 0.85
2 0.98 0.97 0.84
different cleaning agents did not change the selectivity or separation
3 0.99 0.90 0.60
properties of the membrane. Therefore, all of the cleaning agents
4 0.98 0.98 0.90
tested are compatible with the membranes used.
5 0.93 0.99 0.81
6 0.91 0.91 0.81
7 0.91 0.93 0.69
Conclusions
8 0.82 0.84 0.63
An assessment of biodegradable cleaning agents was carried out in
9 0.87 0.77 0.53
10 0.89 0.87 0.71
this study. A direct single-step cleaning procedure did not fully
11 1.03 1.06 1.05 restore the fouled membranes with all the cleaning agents used. A
high temperature in combination with an alkaline and acid sequence
Table 4: Membrane Foulant Removals for Different Cleaning Procedures gave good cleaning efficiency, except for with the 0.5µm membrane
pore size. Temperature affected the total cleaning efficiency, with
Total Hydrocarbon of Permeate (ppm)
Cleaning Sequence 0.1µm 0.2µm 0.5µm
higher temperatures giving higher flux recoveries. The operating
SurfactronCD50/Ultrasil 115 4.27 3.8 4.94 mode during a cleaning cycle affects the overall outcome, i.e.
Ultrasil 115/Ultrasil 73 4.89 4.83 5.01
reducing the cleaning TMP gave significant flux recovery, particularly
Derquim+/Ultrasil 73 4.79 4.55 4.87
Ultrasil 73/Derquim+ 4.65 4.79 4.19
for the membrane with the largest pore size. This study
demonstrates that the cleaning efficiency of a fouled membrane is
very much dependent on the choice of cleaning agents, the
SurfactronCD50; however, the cleaning efficiency is higher for sequence in which they are used and the cleaning cycle itself (i.e.
SurfactronCD50. This may be due to differences in the solution cleaning operating mode). Further studies are required for a
properties, as SurfactronCD50 contains surfactant and organic acid, comprehensive assessment and recommendation of cleaning
whereas Ultrasil 73 is mainly EDTA solution. Therefore, the protocols best suited for a specific type of membrane and
effectiveness of SurfactronCD50 is stronger due to solubilisation of application (i.e. type of foulant). ■
oil and inorganic foulants. Lindau et al.
11
reported a similar trend of
cleaning efficiency using Ultrasil 75 (pH 1.5) and Ultrasil 70 (pH 2) for Acknowledgements
membranes fouled by oily wastewater. As slightly better results were These investigations were carried out with financial support from the
obtained, Derquim+ and SurfactronCD50 were therefore used for Norwegian Research Council (project number: 163505/S30) and several
further assessment of temperature and concentration effects. Neither industry partners: Shell Technology Norway AS, StatoilHydro, Total E&P
agent could totally clean the membrane in a single step. Norge AS, Chevron Energy Technology Company, DNV, Champions
Technology and Vetco Aibel AS. The scaling and corrosion inhibitor
A comparison of all tested matrices of cleaning combinations is shown SERDOX and SurfactronCD50 from Champion Technology are
in Figure 4 and summarised in Table 3. Efficiency is given as a fraction gratefully acknowledged.
1.
www.ospar.org/documents/dbase/decrecs/recommendations/ 2002;195:265. 9.
www.ospar.org/documents/dbase/decrecs/agreements/
0604e_Rec%20amending%20Rec%2001-1.doc 5. Bartlett M, Bird MR, Howell JA, J Memb Sci, 1995;105:147–57. 05_15e_reference%20method%20oil%20in%20produced%20
2. Bilstad T, Espedal E, Wat Sci Tech, 1996;34:239–46. 6. Tragardh G, Desalination, 1989;71:325–35. water.doc
3. Lee JM, Frankiewicz T, SPE Annual Technical Conference and 7. Hannisdal A, Orr R, Sjoblom J, J Disp Sci Tech, 2007;28:361–9. 10. Zeman LJ, Zydney AL, Microfiltration and Ultrafiltration, New
Exhibition, 2005, Paper Number 95735. 8. Zhang GJ, Liu ZZ, Song LF, et al., Desalination, 2004;170: York: Marcel Dekker, 1996;453–61.
4. Liikanen R, Yli-Kuivila J, Laukkanen R, J Memb Sci, 271–80. 11. Lindau J, Jonsson A-S, J Membr Sci, 1994;87:71–8.
112
EXPLORATION & PRODUCTION – VOLUME 7 ISSUE 1
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 |
Page 125 |
Page 126 |
Page 127 |
Page 128 |
Page 129 |
Page 130 |
Page 131 |
Page 132 |
Page 133 |
Page 134 |
Page 135 |
Page 136 |
Page 137 |
Page 138 |
Page 139 |
Page 140 |
Page 141 |
Page 142 |
Page 143 |
Page 144 |
Page 145 |
Page 146 |
Page 147 |
Page 148 |
Page 149 |
Page 150 |
Page 151 |
Page 152 |
Page 153 |
Page 154 |
Page 155 |
Page 156