Final Product Ethanol Analytical Options

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Dana Patterson
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1 Final Product Ethanol Analytical Options for Sulfate, Chloride, Particulates and Cations

2 Limits for Sulfate in Ethanol: Changing Landscape in Fuel Blend Requirements EXPORT MARKETS: Certain foreign buyers have tighter standards for existent sulfate, acidity and trace metals. Longer shipping times oblige documentation of potential sulfate at manufacturer site. Larger shipments (e.g., tankers) increase financial risk in event of rejection due to return transport cost and missed contract commitment penalties. 2

3 Limits for Sulfate in Ethanol: Changing Landscape in Fuel Blend Requirements DOMESTIC MARKETS: Existent and potential sulfate added to certain buyer COA requirements. Tight economics in ethanol production make hold&blend off less attractive. Alternative feedstocks and nontraditional ethanol sources can increase existent sulfate and/or potential sulfate. Pressure distillation plants already have occasional excursions beyond the current standard. Revised ASTM standards may specify lower sulfate limits for mid-range blends. 3

4 Pressure from Petroleum Producers/Refiners/Marketers The Gnarly Gnarlingtons ATTEND and VOTE in semiannual ASTM meetings! Worst case example: we would need to maintain a final blend sulfate level of 0.4 ppm. So, hypothetically: ethanol in E15 could be limited to ~2.7 ppm sulfate. ethanol in E20 could be limited to ~2.0 ppm sulfate. ethanol in E50 could be limited to ~0.8 ppm sulfate. All ethanol sold into open markets could need to meet or exceed requirement of E50. 4

5 Why is sulfate such a concern? The Unverified Arizona Observations (sulfate) specification limit is intended to help alleviate premature pump filter clogging at gasoline stations and prevent fuel injector problems in some automobiles ATTEND and VOTE in semiannual ASTM meetings! David Harvey, CITGO s manager of fuels quality technology and technical services,

6 Understanding Potential Sulfate Sulfate (or sulfuric acid) in Ethanol Reported as existent sulfate. Major contributor to high acidity and low phe. 6

7 Understanding Potential Sulfate Sulfite (or sulfurous acid) in Ethanol The other component of potential sulfate. Minor contributor to high acidity and low phe. Weak acid, so some volatility. Often converted in QC lab to sulfate. Converts slowly to sulfate in storage and transport: 2 SO H 2 O + O 2 2 H 2 SO 4 7

8 Understanding Existent & Potential Sulfate Supporting your Production Team Chemical reductions can avoid or moderate issues. Sulfuric acid for distillation/evap deposit control: contributes sulfate. Excess bisulfite for air emissions control: contributes potential sulfate and existent sulfate. Others: For example, sulfamic acid and sodium bisulfate: contributes sulfate. 8

9 Understanding Existent & Potential Sulfate Yeast don t like residual bisulfite, either 50 ppm stress 100 ppm morbidity 9

10 Understanding Existent & Potential Sulfate Supporting your Production Team Operational optimization can avoid or moderate issues. Distillation, Dehydration, Deacid column: Beer column overhead vent More heat and more vacuum to deacid Ethanol losses may increase 10

11 Ion Chromatography in the Production Lab Applying D Generally, 20 minutes required per test. Determination of potential sulfate requires another full test, plus the oxidation step. Standardization and use of sulfite quantification not commonly applied. Cations require different method(s) or different column. Detection limits suitable to future limits? Integrator errors require trained eye when evaluating chromatograms. 11

12 Ion Chromatography in the Production Lab Integrator errors... Existent sulfate test 12

13 Ion Chromatography in the Production Lab Integrator errors... Potential sulfate test 13

14 Ion Chromatography in the Production Lab Existent Potential 14

15 Capillary Electrophoresis (CE) Analysis Electrophoretic Separations Fast separations of inorganic anions and cations (nitrate, chloride, sulfate, ammonium, calcium, sodium, etc.) Counter flow separation mode Contact conductivity detection (patented) Very low detection limits (<10ppb) Requires compatible buffers Injection time can be varied between runs Can measure low concentrations in one run and high concentrations in subsequent run. Instrumentation is relatively straight-forward in comparison Easier creation of on-line systems USED WITH PERMISSION Copyright 2014 MicroChemica 15

16 Capillary Electrophoresis (CE) Analysis LOADING Flushing the sensor module with buffer and sample loads the channels in preparation for the sample injection. USED WITH PERMISSION Copyright 2015 MicroChemica 16

19 Capillary Electrophoresis (CE) Analysis STACKING Taking advantage of the natural phenomenon of ion stacking within the initial phase, the ions are sorted based on their electrical charge. USED WITH PERMISSION Copyright 2015 MicroChemica 19

20 Capillary Electrophoresis (CE) Analysis SEPARATING During the separation, high voltage is applied between the BGE reservoir and the reservoir near the detection electrodes resulting in the ion transport based on mobility. USED WITH PERMISSION Copyright 2015 MicroChemica 20

21 Capillary Electrophoresis (CE) Analysis ANALYZING Start As the individual ion plug is passing by the patent pending embedded conductivity measurement USED WITH PERMISSION Copyright 2015 MicroChemica 21

excluding laptop) Online instrument USED

25 Inorganic Chloride Not currently a challenging spec in U.S., but... Historic spec level of inorganic chloride = 10 mg/kg. Recent ASTM ballot proposed a reduction to 6.7 mg/kg for E15. Certain alternate feedstocks appear to increase final product chloride. On ion chromatograph, hydroxide peak can superimpose on chloride peak false positive for high chloride. Only successfully demonstrated inorganic chloride reduction method involves post-treatment. 25

26 Particulate Identification and Monitoring Suspended metallic solids increase with low ph e high acidity high potential sulfate high chloride (unusual in U.S.) Other fines; e.g., sieve bead dust/fragments 26

27 Particulate Identification and Monitoring B&W Suspended Iron Test (Fe 2 O 3. X H 2 O) (Fe 2 O 3. X H 2 O : Fe 3 O 4 ) 2 : 1 (Fe 2 O 3. X H 2 O : Fe 3 O 4 ) 1.5 : 1 (Fe 2 O 3. X H 2 O : Fe 3 O 4 ) 1 : 1 (Fe 3 O 4 ) 1 : 1 All at 10 ppb, 25 ppb, 50 ppb, 75 ppb, 100 ppb, 150 ppb, 500 ppb, and 1000 ppb 27

28 Particulate Identification and Monitoring B&W Suspended Iron Test Adapted from steam condensate testing Visual composition/concentration possible Also, elemental analysis and crystallography, if desired Customary filters are 0.45u Millipore filters Nuclepore filters used for certain protocols Materials of construction: Housing HDPE, PP, PVC, PET Filters PP, PVC, PC, PTFE, PVDF O-rings EPR (ethylene propylene rubber) or Viton A 28

29 Cations of Interest Copper, iron, sodium, others? COPPER: Experimental work has shown that copper concentrations higher than mg/kg in commercial gasolines can significantly increase the rate of gum formation. Max concentration 0.1 mg/kg some buyers require 0.08 mg/kg. IRON: Some buyers require max concentration 5 mg/kg. SODIUM: Some buyers require max concentration 2 mg/kg. 29

30 Risk Management Option: POST-TREAT For existent sulfate, potential sulfate, chloride, particulates and cations 30

31 Results of commercial post-treatment 200 proof ethanol in 200 proof ethanol out Chloride = 0.66 ppm Sulfate = 7.72 ppm SO 2 Chloride = 0.77 ppm* Sulfate = 0.03 ppm *Note OH - elution At ~5 minutes

32 CONGRATULATIONS!

33 Thank You! 33 Thanks for your help Midland Scientific Especially, Kylie Fuel Ethanol Laboratory Managers' Conference 11/6/2015