Improved Robustness and Chemical Resistance of Nanofiltration Membranes GeoEnergy 2018 Zamir.Alam@suez.com Matt.Boczkowski@suez.com Z. Alam, M. Boczkowski, B. Chaudhari, P. Eriksson, SUEZ Water Technologies and Solutions, 2018: Advancement of Nanofiltration Membrane: Improved Robustness and Chemical Resistance
Agenda Historical performance issues Recent Improvement in membrane robustness and its relevance to EOR • Higher pH tolerance • Alkaline cleaning • Biocide compatibility Conclusions
Historical data Umm-Lujj Desalination Plant Seawater RO plant NF Plant Description NF Feed Water Quality commissioned in 1986 Parameter Value Parameter Value In 2000, one of the two Capacity, m 3 /hr pH 6 234 trains converted to NF- (adjusted) Recovery 65% SWRO 24 – 34 °C Temperature # of NF module 162 SDI 3.5 Courtesy (Hassan et al. & Stage 1 TDS 46,500 A.A. Al-Hajouri et al. )
Historical data Hardness & Sulfate Rejection after Alkaline Clean 120 Umm-Lujj: Impact 100 % Rejection of Alkaline Clean 80 2000 to 2001 60 40 20 After 3 Alkaline Cleans 0 Total Hardness Calcium Magnesium Sulfate Sulfate rejection decreased from >99% to 98.7% Initial After Clean 1 After Clean 3 Hardness rejection decreased from 97% to 73% Hardness rejection is an important consideration for drilling fluids, well completion fluids and ASP flooding Courtesy Hasan et al
Positive impact of acid on membrane performance 8.1 pH 6.1 pH NF demonstration study by Saline Water Conversion Impact of Feed Water pH: Corporation - SWCC (Courtesy Abdullatef et al) Historical Performance 2007-2008 Rejection of most the ions decreased when acid dosing was eliminated (Feed pH increased to 8.1 from 6.1)
Improved robustness: High pH Tolerance
Field trial at pH > 8 50 8000 Seawater natural pH is around 8 Permeate Sulfate, mg/L as SO 4 -- 40 Feed Sulfate, mg/L as SO 4-- 6000 Earlier versions required pH 30 adjustments to less than 7 4000 Feed Sulfate, ppm incurring additional costs After CIP Permeate S ulfate, ppm 20 Before CIP Newer generation of SWSR 2000 membranes can operate at 10 seawater natural pH (>8) without any noticeable 0 0 28-Oct-14 7-Dec-14 16-Jan-15 25-Feb-15 6-Apr-15 16-May-15 deterioration in sulfate rejection NF membranes are commonly used in SRPs and low salinity injection systems (EOR)
Improved robustness: Alkaline Clean
Accelerated Test Developed an accelerated testing protocol to examine the robustness of newer NF formulations • Shorter duration • Less resource intensive Validated the new protocol by comparing the results from the accelerated testing with pilot testing
Standard wet test and CIP conditions Baseline & performance test with Seawater Membrane performance test with MgSO4 1 • • Feed solution: 2000 ~2200 ppm MgSO4 Feed solution: Seawater (NF pilot Seawater feed from Tuas site) • Feed pH: 6.86~7.00 • Feed pH : 7.8 -8.20 • Feed pressure: 110±1 psi • Feed pressure: variable (depends on membrane flux) • Feed temperature: 25±1 deg.C • Feed temperature: 25±0.5 deg.C • • Permeate recovery: 15~17 % Membrane flux: 16~ 17 gfd • • Wet Test duration: 4 hrs.(initial test) 24 hrs. (after RO water Permeate recovery: 15±1% compaction) 24 hrs. (after 10 CIP’s) • Test duration: 24hr 2 • Water passing criteria: 98% Rej Acidic CIP conditions Alkaline CIP conditions 3 4 • CIP solution: Acidic cleaner Kleen MCT-882 • CIP solution: Alkaline cleaner Kleen MCT-511 • Dosage wt. : 2.0 % • Dosage wt.: 2.0 % • CIP solution pH : 2.50±0.5 • CIP solution pH : 10.70 ±0.5 • CIP solution temperature (during CIP) : 35±1 deg.C • CIP solution temperature (during CIP) : 35 ±1deg.C • Feed pressure : 60±2 psi • Feed pressure : 60±2psi • Concentrate flow: 5 lpm • Concentrate flow: 5 lpm • CIP Duration (total): 3 hrs. (1hr circulation + 1hr soaking + • CIP Duration (total) : 6 hrs. (2hr circulation + 2hr soaking + 1hr circulation) 2hr circulation) Alkaline CIP (6hrs) → Acidic CIP(3hrs) -> Seawater wet test (24hrs) = 1 CIP cycle Repeated 12 times to established the membrane performance deterioration trend
Accelerated test vs. field trial Sulfate Rejection: Accelerated Testing Vs Field Hardness Rejection: Accelerated Testing Vs Field Trial Trial 100 Hardness Rejecttion, % 100 Sulfate Rejecttion, % 99,8 90 99,6 Field Trial Field Trial 80 99,4 Accelerated Lab Accelerated Lab Test Test 70 99,2 99 60 Membranes behave differently in different seawaters, pHs, biocides, temperatures and so on. Waters for EOR vary from one source to the next. Accelerated testing enables to optimize membrane selection without delaying the project and is an important risk mitigating step
Improved robustness: Biocide Compatibility
Biocides can Non-Oxidizing potentially affect Biocides are used the robustness of to control NF membrane Why Alternative Microorganism Membrane in pipelines, Biocides fouling e.g., SRB Biofilm Loss of formation rejection
Compatibility Test Soak Test: Prescreening at different biocide concentration at target temperature and pH Monitor permeability and rejection twice per day for 7-days Continuous Test: Continuous test at maximum compatible concentration for ~100,000 ppm-hrs Monitor pressure, flow, conductivity continuously Monitor sulfate rejection twice per day Monitor cleanability every 50,000 ppm- hrs
Soak Test: THPS Based Biocide THPS Based Biocide A-Value Trend (Before & After Biocide Soaking) 20 18 16 14 A-Value 12 Impact on membrane robustness 10 8 varies with manufacturer of the 6 4 THPS based biocides 2 0 ppm-hr 10000 1000 100 20 5 0 No impact on MgSO4 rejection Baseline 16.86 13.76 13.28 12.88 15.38 13.91 After 24-hrs Soaking 15.69 13.16 13.08 12.78 15.34 13.66 even at 10,000 ppm dose After 244-hrs Soaking 13.64 12.51 12.47 12.27 14.88 13.69 Small decrease in permeability with one of the THPS based biocides at very high concentration Longer term test with 1000 ppm dose
Continuous Test Permeability & Rejection Trend with 100 & 1000 ppm of THPS based Biocide 25 120 No noticeable decrease in either 100 20 MgSO 4 Rejection (%) permeability or rejection Permeability 80 15 60 after 75,000 ppm-hrs of 10 40 continuous test 5 20 <8% decrease in permeability <2% decrease in MgSO4 rejection 0 0 200 900 2200 2200 9200 12200 24200 27200 32200 48200 59200 73200 75200 ppm - hr Permeability 11.86 11.56 11.56 11.24 10.82 10.86 10.89 11.18 11.08 11.12 10.94 10.96 11.00 % Rejection 99.46 99.50 99.50 99.04 99.03 99.07 99.04 99.03 99.16 99.17 97.65 97.63 97.95 pH can decrease with THPS addition A common and inexpensive biocide. However, not every manufacturer is equal and MSDS’ don’t tell the whole story.
Continuous Test In a similar fashion to THPS based biocides, we tested Glutaraldehyde based biocides Even less variability in permeability and rejection was observed vs control than in the case of THPS A common and inexpensive biocide. However, not every manufacturer is equal and MSDS’ don’t tell the whole story.
Conclusions Improved membrane performance for EOR and Water injection applications • Higher pH tolerance • Alkaline cleaning • Biocide compatibility Validated testing method to evaluate membranes for new EOR applications with different water characteristics and biocides
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