of Nanofiltration Membranes GeoEnergy 2018 Zamir.Alam@suez.com - - PowerPoint PPT Presentation

Improved Robustness and Chemical Resistance

• f 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

Umm-Lujj Desalination Plant

Seawater RO plant commissioned in 1986 In 2000, one of the two trains converted to NF- SWRO Courtesy (Hassan et al. & A.A. Al-Hajouri et al. )

NF Feed Water Quality

Parameter Value pH 6 (adjusted) Temperature 24 – 34 °C SDI 3.5 TDS 46,500

NF Plant Description

Parameter Value Capacity, m3/hr 234 Recovery 65% # of NF module 162 Stage 1

Historical data

Umm-Lujj: Impact

• f Alkaline Clean

2000 to 2001

After 3 Alkaline Cleans

Sulfate rejection decreased from >99% to 98.7% Hardness rejection decreased from 97% to 73%

Courtesy Hasan et al

20 40 60 80 100 120 Total Hardness Calcium Magnesium Sulfate

% Rejection

Hardness & Sulfate Rejection after Alkaline Clean Initial After Clean 1 After Clean 3

Historical data

Hardness rejection is an important consideration for drilling fluids, well completion fluids and ASP flooding

Impact of Feed Water pH: Historical Performance 2007-2008

NF demonstration study by Saline Water Conversion Corporation - SWCC (Courtesy Abdullatef et al) Rejection of most the ions decreased when acid dosing was eliminated (Feed pH increased to 8.1 from 6.1)

8.1 pH 6.1 pH

Positive impact of acid on membrane performance

Improved robustness: High pH Tolerance

Seawater natural pH is around 8 Earlier versions required pH adjustments to less than 7 incurring additional costs Newer generation of SWSR membranes can operate at seawater natural pH (>8) without any noticeable deterioration in sulfate rejection

10 20 30 40 50 2000 4000 6000 8000 28-Oct-14 7-Dec-14 16-Jan-15 25-Feb-15 6-Apr-15 16-May-15

Permeate Sulfate, mg/L as SO4-- Feed Sulfate, mg/L as SO4--

Feed Sulfate, ppm Permeate S ulfate, ppm Before CIP After CIP

Field trial at pH > 8

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

• Feed solution: 2000 ~2200 ppm MgSO4
• Feed pH: 6.86~7.00
• Feed pressure: 110±1 psi
• Feed temperature: 25±1 deg.C
• Permeate recovery: 15~17 %
• Wet Test duration: 4 hrs.(initial test) 24 hrs. (after RO water

compaction) 24 hrs. (after 10 CIP’s)

• Water passing criteria: 98% Rej

Membrane performance test with MgSO4 Baseline & performance test with Seawater

• CIP solution: Alkaline cleaner Kleen MCT-511
• Dosage wt.: 2.0 %
• CIP solution pH : 10.70 ±0.5
• CIP solution temperature (during CIP) : 35 ±1deg.C
• Feed pressure : 60±2psi
• Concentrate flow: 5 lpm
• CIP Duration (total) : 6 hrs. (2hr circulation + 2hr soaking +

2hr circulation)

Alkaline CIP conditions

• CIP solution: Acidic cleaner Kleen MCT-882
• Dosage wt. : 2.0 %
• CIP solution pH : 2.50±0.5
• CIP solution temperature (during CIP) : 35±1 deg.C
• Feed pressure : 60±2 psi
• Concentrate flow: 5 lpm
• CIP Duration (total): 3 hrs. (1hr circulation + 1hr soaking +

1hr circulation)

Acidic CIP conditions

Alkaline CIP (6hrs) → Acidic CIP(3hrs) -> Seawater wet test (24hrs) = 1 CIP cycle Repeated 12 times to established the membrane performance deterioration trend

• Feed solution: Seawater (NF pilot Seawater feed from Tuas site)
• Feed pH : 7.8 -8.20
• Feed pressure: variable (depends on membrane flux)
• Feed temperature: 25±0.5 deg.C
• Membrane flux: 16~ 17 gfd
• Permeate recovery: 15±1%
• Test duration: 24hr

Standard wet test and CIP conditions

1 2 3 4

99 99,2 99,4 99,6 99,8 100

Sulfate Rejecttion, %

Sulfate Rejection: Accelerated Testing Vs Field Trial

Field Trial Accelerated Lab Test 60 70 80 90 100

Hardness Rejecttion, %

Hardness Rejection: Accelerated Testing Vs Field Trial

Field Trial Accelerated Lab Test

Accelerated test vs. field trial

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

Why Alternative Biocides

Non-Oxidizing Biocides are used to control Microorganism in pipelines, e.g., SRB Biofilm formation Biocides can potentially affect the robustness of NF membrane Membrane fouling Loss of 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

Impact on membrane robustness varies with manufacturer of the THPS based biocides No impact on MgSO4 rejection even at 10,000 ppm dose Small decrease in permeability with

• ne of the THPS based

biocides at very high concentration Longer term test with 1000 ppm dose

10000 1000 100 20 5 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 After 244-hrs Soaking 13.64 12.51 12.47 12.27 14.88 13.69 2 4 6 8 10 12 14 16 18 20 A-Value THPS Based Biocide A-Value Trend (Before & After Biocide Soaking) ppm-hr

Soak Test: THPS Based Biocide

No noticeable decrease in either permeability or rejection after 75,000 ppm-hrs of continuous test

<8% decrease in permeability <2% decrease in MgSO4 rejection

pH can decrease with THPS addition

200 900 2200 2200 9200 12200 24200 27200 32200 48200 59200 73200 75200 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

20 40 60 80 100 120 5 10 15 20 25 MgSO4 Rejection (%) Permeability

ppm - hr

Permeability & Rejection Trend with 100 & 1000 ppm of THPS based Biocide

Continuous Test

A common and inexpensive biocide. However, not every manufacturer is equal and MSDS’ don’t tell the whole story.

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

Continuous Test

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