Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS...

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Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation: Efficacy, Mechanisms and Residuals Derrick Okull, PhD Technical Service Manager Dupont Nutrition and Biosciences

Transcript of Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS...

Page 1: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation: Efficacy,

Mechanisms and Residuals

Derrick Okull, PhDTechnical Service ManagerDupont Nutrition and Biosciences

Page 2: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

Additives

NOT chlorine/bleach Buffered sodium chlorite solution, antibiotic-free aqueous

solution Historically used in food processing/water treatment

industries for contamination control/sanitation 14yr history in fuel ethanol – GRAS status, with expert

concurrence, for use as a processing aid in potable alcohol and fuel ethanol production with resulting distillers’ grains approved for use in animal feed (cattle, swine, poultry).

Controls lactic and acetic acid producing bacterialcontamination

Suitable for ethanol production from sugar and/or grain substrates

Generated, concentrated solutions traditionally used in paper bleaching

Stabilized Chlorine Dioxide (ClO2) – What is it?Property Value/Description

Crystallization Point -12°C 10°F

Freezing Point -18°C 0°F

Boiling Point 106°C 223°F

pH 9.5 to 9.8

Density (g/mL)

@ 20 °C

1.18 to 1.21

Color Clear light yellow solution

Odor Faint chlorine-like smell

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Page 3: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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Stabilized Chlorine Dioxide – how it works

A solution of 15 – 25 % Sodium Chlorite Chlorine dioxide is formed under acidic pH

conditions When applied correctly, inactivates bacteria

without harming yeast Activity is pH dependent – Need pH < 5.4 to be

effective

ClO2- + H+ HClO2 + ClO2

Chlorite + Acid Chlorous acid + Chlorine dioxide

Chlorite + Low pH mash/other substrate

Low pH/Acidic conditions drive conversion of Chlorite into more active form to kill bacteria on contact

Page 4: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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Bacterial Contamination in the Ethanol Process:

A Primer

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Page 5: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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ETHANOL PRODUCTION - DRY GRIND PROCESS OVERVIEW

Grinding/Slurry/ Cook

Liquefaction

Fermentation

Distillation

Corn Oil

Ethanol

DDGS

Back Set Syrup

CO2

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Page 6: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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WHERE DOES CONTAMINATION COME FROM?

CO2

Beer well

Distillation

Liquefaction*

Heat exchangers

Cook

Fermentation~92ºF, 60hrs

Dry ground cornYeast propagation

Significant source of infection / re-contamination

Mash headers/piping/deadlegs Conducive temperature – 88 – 92ºF pH – 4.9 – 5.6 Food source – sugar, proteins, and

trace/micronutrients Moisture – mash Protection - biofilms

Drop lactic acid in a contaminated process

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Page 7: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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WHY DOES BACTERIA CAUSE LOSSES?

Competition with inoculant yeast for nutrients

Increased production of organic acids (lactic and acetic) by contaminant bacteria instead of ethanol

Inhibition of yeast Recycle through backset can also

compound inhibition Downtime, cleaning costs from fouling

as a result of unfermented sugar going into distillation

Decline in Ethanol titer from a contaminated process

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Page 8: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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Controlling Contamination

Process Controls Antimicrobials Antibiotics

CIP/ SanitationTemperature High SolidsHigh Yeast inoculumpH Control/ Acids

Hop AcidsOxidatives

eg ClO2, H2O2,IodineHOCl

Quaternary CompoundsGlutaraldehydeBacterial Peptides

Virginiamycin (Lactrol™) MonensinErythromycinPenicillinCombinations

Cellular Targets of antibioticsCellular Targets of some common disinfectants

http://www.connect2cleanrooms.com/news-article/Rotational-Cleaning

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Example Plant Data

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Page 10: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

Additives

Lactic acid levels in a process before and after addition of ClO2

ClO2 added

Baseline

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Page 11: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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ClO2 Plant Performance

ClO2 was trialed in conjunction with antibiotics at a 100 MGPY Dry Grind Ethanol Plant experiencing an active infection resulting in elevated lactic acid levels, high drop sugars, and decreased ethanol yields.

0.418

0.413

0.4090.41

0.4110.4120.4130.4140.4150.4160.4170.4180.419

Baseline ContaminatedEt

hano

l/Sol

ids

Ethanol Yield (EtOH/Solids)

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0 10 20 30 40 50 60 70

Con

c. (%

w/v

)

Time(Hrs)

Lactic Acid (%w/v)

Baseline ContaminatedCopyright @ 2019 Dupont All Rights Reserved

Page 12: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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ClO2 Performance During Active Contamination

0.00

0.05

0.10

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0.20

0.25

0.30

0.35

0 10 20 30 40 50 60 70

Con

c. (%

w/v

)

Time(Hrs)

Lactic Acid (%w/v)

Baseline Contaminated FERMASURE® XL

0.00

0.02

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Con

c. (%

w/v

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Time(Hrs)

Drop Glucose (%w/v)

Baseline Contaminated FERMASURE® XL

Dosing with ClO2 helped to reduce the contamination in the system and move the plant back towards baseline profiles than treatment with antibiotics alone.

ClO2 ClO2

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Page 13: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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ClO2 Performance During Active Contamination

Dosing with ClO2 helped to decrease lactic acid concentration in the system and move yields and sugar data back to baseline.

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

0 10 20 30 40 50 60 70

Con

c. (%

w/v

)

Time(Hrs)

Ethanol (%w/v)

Baseline Contaminated FERMASURE® XL

0.418

0.413

0.418

0.4090.41

0.4110.4120.4130.4140.4150.4160.4170.4180.419

Baseline Contaminated FERMASURE® XL

Etha

nol/S

olid

s

Ethanol Yield (EtOH/Solids)

ClO2ClO2

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Page 14: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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Possible Dosing Points

Milling

Atm.

Yeast Propagation

Fermentation

Distillation

Ethanol

Grain Feedstock

(Corn/Wheat)

Liquefaction

CO2

Dehydration

Ethanol to Market

EtOH-blended gasoline

DDGS

Evaporation

Solids Separation

Distillers Corn Oil

Transfer to Animal Feed producer

Blended Animal Feed

Blending Process Stable Product

Packaging/Storage/Transportation

Transport to customer by

tote

Engineering controls in place to limit exposure potential to workers

Sodium Chlorite (NaClO2)

Blending Process at Toll Manufacturing facility

Other Ingredients

H2O

Customer Process

Customer must receive guidance on recommended material safe

handling, PPE and storage requirements

Proven safe

(GRAS status) and

approved for use in

production of potable

alcohol and fuel ethanol

production with co-

products intended for

use in animal feed.

Customer storage

Product Trail

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Page 15: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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Assumptions: Continuous fermentation – vessels in series Dosing in the first two vessels in the train at up to 1000ppm (0.1% of working volume of dosed vessels) At drop, dilution has occurred across the system – total working volume includes all vessels in the train Stabilized ClO2 contains 15-22% sodium chlorite (NaClO2) At this dose, the system will have an estimated 499kg of chlorite End products of reaction in acidic environment are NaCl (salt) and NaClO3 (chlorate)at about a 2:1

ratio, with the chlorate getting further reduced to NaCl

Vol ClO2 dose (ppm) Vol of FXL (gal) Wgt (kg) NaClO2 (kg)Preferm vol 180000 1000 180 720 159Ferm 1 387000 1000 387 1548 341Total working vol 1211000 468.2 567 2268 499

Residuals in DDGS

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Page 16: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

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Typical Sodium in DDGS ~ (2000 ppm) 0.2% Potential from high dose ClO2 – 155 ppm (0.0155%)

https://www.card.iastate.edu/products/books/distillers_grains/pdfs/chapter5.pdf (K. Bregendhal, Chapter 5)

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Page 17: Stabilized Chlorine Dioxide in Fuel Ethanol Fermentation ......14yr history in fuel ethanol – GRAS status, with expert concurrence, for use as a processing aid in potable alcohol

Thank you!

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