www.process-design-center.com Corrosion issues of ethanol blends and the effect of water ABLCNext Conference – San Francisco Afternoon Track B – Ethanol, Diesel and Jet Fuels November 11, 2014 By: Hans Keuken, CEO
www.process-design-center.com
Corrosion issues of ethanol blends
and the effect of water
ABLCNext Conference – San FranciscoAfternoon Track B – Ethanol, Diesel and Jet FuelsNovember 11, 2014By: Hans Keuken, CEO
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Composition of ethanol containing fuels
Code
Composition
Countries Western
Europe
today
USA today
(Western
Europe in
near future)
2010 USA
EPA
approval
cars > 2000
Brazil USA /
Europe
Brazil
E5 E10 E15 E25 E85 E100
min 95%
gasoline
max 5%
anhydrous
ethanol
max 10%
anhydrous
ethanol
min 90%
gasoline
max 15%
anhydrous
ethanol
min 85%
gasoline
min 75%
gasoline
100%
hydrous
ethanol
(contains
on average
5.3 vol.%
water)
max 25%
anhydrous
ethanol
max 85%
anhydrous
ethanol
min 15%
gasoline
~5.3% water
Gasoline blends for
use in regular cars
Flex Fuel
Vehicles
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Hydrous & anhydrous ethanol
•Hydrous ethanol can be distilled up to 3.5 volume%
water (limit = azeotrope)
•Anhydrous ethanol is further dehydrated to contain
less water typically < 1%
•Dehydration units require additional capital &
operating cost (energy)
•Brazilian prices in US$/ltr. can be found at www.cepea.esalq.usp.br/english/ethanol/?id_page=243
Hydrous ethanol is approximately 15% cheaper
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Conventional wisdom in blending
•Gasoline and water do not mix (2-liquid-phase system).
•One expects simply water to create corrosion.
•Ethanol has to be free of water to be blended in gasoline.
•Blends of dry ethanol with gasoline will pick-up water, e.g. from air humidity, logistical systems.
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Shell confirmation hydrous ethanol for E10+ in EU
Shell Research - Amsterdam Sept. 2006
- Straight gasoline: haziness observed at -5ºC
- Straight gasoline + 5% hydrous Ethanol (hE5): haziness observed at -34ºC
- 10, 15 and 20% hydrous Ethanol: haziness could not be detected at -60ºC
Phase separation is not observed in any of the
above blends!
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Phase Stability Ethanol Blends in EU
7
E10E15
E85
ANP
ASTM D 4806
EN15376 ANP Hydrous
(E100)
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Effect of 1% TBA (C4 alcohol)
8
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Phase Stability Ethanol Blends European E1-E5 versus
US E10 and US E15 based on RFA 2012 data
9
E85
ANP
ASTM D 4806
EN15376 ANP Hydrous
(E100)
US
E10
US
E15
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A lower aromatic content results in a lower water tolerance
E15 blend can tolerate approximately
0.75v% water at 60°F
Copyright © 2012 Renewable Fuels Association.
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Wet Corrosion Tests by Sasol
• Sasol’s “wet corrosion” tests (ASTM D665) of E2 and E10 on aluminum parts.
• Wet corrosion is corrosion in the presence of water
• Sasol found:
• The E0 and E2 blends were corrosive during the wet corrosion test.
• These fuels required additisation in order to prevent wet corrosion.
• The E10 blends were not corrosive in the wet corrosion test.
Presented at the XVIII International Symposium on Alcohol Fuels
(Delhi – India ISAF 2010)
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Ternary Diagram & Phase Separation
12
Weight Percent Ethanol
20%
40%
60%
80%
ETHANOL
WATER
20%
40%
60%
80%
Weight P
erce
nt W
ater
GASOLINE 20%40%60%80%
Weight Percent Gasoline
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Conductivity E10’s adding salt water
Salt Water E10, dry E10, 0.2% water E10, 0.5% water
0,10% 0,003 0,010 0,015
0,20% 0,015 0,008 0,010
0,30% 0,006 0,010 0,011
0,40% 0,015 0,009 0,010 salt drops out
0,50% 0,203 0,009 0,012 free water
0,60% 0,276 0,009 0,012
0,70% 0,259 0,009 0,012
0,80% 0,201 0,020 0,013
0,90% 0,185 0,018 0,013
1,00% 0,182 0,018 0,012
Test by SGS to see if more
hydrous E10 picks up more
salts?
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Conductivity E10’s adding salt water
Conductivity E10's adding salt water
-0,050
0,000
0,050
0,100
0,150
0,200
0,250
0,300
0,00% 0,20% 0,40% 0,60% 0,80% 1,00% 1,20%
% salt water (3 gram/liter) added
Co
nd
uc
tiv
ity E 10 dry
E10, 0.2% water
E10, 0.5% water
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Sulfate deposits in E85
•Sulfate deposits block injectors in E85 Flex Fuel Vehicles in Sweden when they drive on E85 only.
• The solubility of the Ca, K, Mg and Na sulfates in E85 happens to be almost zero ppm.
•Brazil does not have sulfates blocking injectors, but they use full hydrous E100 instead of anhydrous E85.
•Besides the effect of solubility, these K, Na, Ca and Mg sulfates also form hydrates.
These hydrated crystals will probably not survive and disintegrate when exposed to the higher temperatures in the injectors.
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Clean injector after 35.000 km partly driving on hydrous E85
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Solubility of Na2SO4 in E85
Vol.% water in the fuel ethanol 0.01 0.11 0.25 1.01 2.51 5.01
Sulfate content E85 (adding 1000 mg/kg Na2SO4) 0.09 0.11 0.14 0.18 12.9 40.6
Precipitation
85% of current max. spec = 3,4 ppm
0
5
10
15
20
25
30
35
40
45
0 1 2 3 4 5 6
Su
lfa
te s
olu
bil
ity (
pp
m(m
))
Vol.% water
E85 - SO42- solubility
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Dry Corrosion Research Japan (JARI) SAE paper 2005-01-3708 Appendix 3.1 Copyright © 2005 SAE International
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Dry Corrosion Research Japan (JARI)SAE paper 2005-01-3708 Appendix 1.1 Copyright © 2005 SAE International
Material in
fuel systemType
Gasoline
100%
E50 with
150 ppm water
(overall) *
E50 with
500 ppm water
(overall) *
E50 with
2000 ppm water
(overall) *
E50 with
10.000 ppm water
(1%, overall) *
Aluminum A1050 OK complete dissolution complete dissolution complete dissolution OK
Aluminum A6061 OK complete dissolution complete dissolution OK OK
Aluminum ADC12 OK reduction in mass reduction in mass OK OK
Steel change in surface OK OK OK change in surface
Copper change in surface change in surface change in surface change in surface change in surface
Nickel OK OK OK OK OK
Zinc OK change in surface change in surface OK change in surface
Tin OK change in surface change in surface change in surface OK
Legend: OK No change observed
change in surface change in color for instance, but no reduction in mass
* 1 vol% overall water in E50 means a concentration of 2 vol% water in the added ethanol
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Alcoholate (dry) corrosion of aluminum
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Alcoholate (dry) corrosion of aluminum
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Dry corrosion E5, E10, E15 and E20
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Water as inhibitor in E100
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Effect of water on alcoholate corrosion
A little water works as fluoride in
toothpaste and avoids corrosion
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Hydrous ethanol standard (NTA 8115) for E10+ blending
at 2,52%
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“Water Injection”70 years proven technology!
2010
1940’s
1983
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Energy efficiency in a modern down sized turbo
charged Volvo S60 T4F (Flex Fuel Vehicle)
2,15
2,2
2,25
2,3
2,35
2,4
2,45
2,5
2,55
2,6
2,65
0,00% 1,00% 2,00% 3,00% 4,00% 5,00% 6,00% 7,00%
Water fraction (vol)
MJ
co
ns
um
ed
pe
r k
m
Normal Distance Long Distance
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Tests results by the European Commission
Emission tests of hydrous versus anhydrous to quantify the effect of
a higher water content in ethanol containing gasoline.
E10 - hE10
E15 - hE15
E70 - hE70
E85 - hE85
“The results suggest that there are no marked differences on the
regulated and unregulated emissions when hydrous ethanol blends are used instead of anhydrous ethanol blends.”
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Netherlands in 2008 hE15 opening by Minister Cramer
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Currently 181 gas stations selling hydrous E15
6.5 years experience
Approximately:
5000 tankings/day
and
100,000 cars
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General technical conclusions
• E10 in the US is less corrosive than E10 in Europe due to a higher water content in the ASTM D 4806.
• We need a minimum water content in fuel ethanol.
• We still need a maximum water content to avoid phase separation (wet corrosion) issues also in mixed tanking scenario’s.
• More hydrous ethanol blends do not pick up more contaminants.
• A higher water content in E85 avoids sulfate deposits blocking injectors.
• Water injection has a positive effect on the Well to Wheel energy efficiency and reduces overall emissions.
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• The water tolerance of the current US gasoline is not high enough to allow full hydrous E15 throughout the country.
• Full hydrous E85 is feasible next to an anhydrous E10 or E15.
This will not result in phase separation in mixed tanking scenarios!
• Hydrous E85 can be 10% cheaper than the current anhydrous E85 and could stimulate the sales of E85 and help to overcome the blending wall.
• Skipping expensive dehydration units would be of interest for new
2G advanced ethanol plants.
“Hydrous ethanol” potential in US
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