Hohenheim University, Section of Fermentation Technology, Research Distillery

Energy Saving in Ethanol Production During the Mashing Process

3. European Bioethanol Technology Meeting

Association of Cereal Research, Detmold (Germany)

24. – 25. April 2007

PD Dr. Thomas Senn

Hohenheim University, Section of Fermentation Technology, Research Distillery

Energy Saving in Mashing Process

• High gravity mashing• DS% up to 35%• Less water to heat up

• STARGEN-Process• Maximum temperature of 59°C in mashing• No additional thermal energy during mashing if

hot water or stillage backset is used

Hohenheim University, Section of Fermentation Technology, Research Distillery

High Gravity Mashing• Mashing Conditions

• Stillage backset 25%; pH 5,0-5,2; 50°C; 30 min– Enzymes

» Liquozyme + Viscozyme Wheat• Liquifaction at 85°C; 60 min

» Start of saccharification and fermentationat 32-34°C

– Enzymes» Spirizyme Fuel + Alcalase

• Isostab 30 ml / m³ of mash• Urea 400g / m³, Phosphoric Acid 100g/m³

Hohenheim University, Section of Fermentation Technology, Research Distillery

Use of thermostable Xylanase Gammaxylanase HTL

Mash viscosity without Xylanase

Hohenheim University, Section of Fermentation Technology, Research Distillery

Einsatz thermostabiler XylanaseGammaxylanase HTL

Mash viscosity using Xylanase

Hohenheim University, Section of Fermentation Technology, Research Distillery

Dependency of EtOH Concentration on DS % in Mash

y = 0,32x + 1,9557R2 = 0,9857

6

7

8

9

10

11

12

13

14

15 20 25 30 35 40

DS %

%vo

l A

Hohenheim University, Section of Fermentation Technology, Research Distillery

Dependency of Ethanol Yield LA/100 kg Wheat on DS % in Mash

y = -0,4564x + 53,446R2 = 0,8617

35

37

39

41

43

45

47

15 20 25 30 35DS %

LA/1

00 k

g W

heat

Hohenheim University, Section of Fermentation Technology, Research Distillery

High Gravity Mashing

• 350 kg Wheat or Triticale / 1000 L of mash• Add thermostable Xylanases with liquifaction

enzymes• After Liquifaction rest pH is lowered to 4,0• Dilute mash to ~ 1,6 m³• Simultaneous saccharification and

fermentation

Hohenheim University, Section of Fermentation Technology, Research Distillery

High Gravity Mashing - Conclusion

• Fermentation efficiency drops, if the ethanol content in the fermented mashes exceeds 10%vol EtOH

• Benefits can be used if mashes are diluted before fermentation – cooling !!

• Fermentation to 10%vol EtOH can be finished within 48 - 52 h

• The process has to be tailored to each plant• Low viscosities lead to benefits in fermentation,

cooling, pumping, stirring, destillation...

Hohenheim University, Section of Fermentation Technology, Research Distillery

Mash Preparation „Genencor Standard“

• Stillage backset 25%; pH 5,7; 57-58°C; 30 min• Enzymes

– Spezyme Ethyl + Optimash BG• Liquifaction at 85°C; 60 min• Start of saccharification and fermentation at

32-34°C• Enzymes

– Fermenzyme L 400 + Protease GC 106• Isostab 30 ml / m³ of mash

Hohenheim University, Section of Fermentation Technology, Research Distillery

Mash Preparation „Hohenheim“

• Stillage backset 25%; pH 5,7• Liquifaction at 85°C; 60 min

• Enzymes– Liquozyme + Gammazyme HTL

• Start of saccharification and fermentation at 32-34°C

• Enzymes– Gammaclast 2 OP + SAN Super 360 L (20%)

• Isostab 30 ml/m³ of mash

Hohenheim University, Section of Fermentation Technology, Research Distillery

Mash Preparation „STARGEN“

• Stillage backset 25%; pH 3,8-4,2; 56-57°C; 2h• Enzymes

– GC 626 + Optimash BG

• Start of saccharification and fermentation at 31-32°C; pH at start 3,5-3,6

• Enzymes– STARGEN 001 + GC 106

• Isostab 30 ml/m³ of mash

Hohenheim University, Section of Fermentation Technology, Research Distillery

Duration of Fermentations

0

2

4

6

8

10

12

0,00 10,00 20,00 30,00 40,00 50,00 60,00 70,00 80,00

Time h

%vo

l EtO

H

Genencor Standard

STARGEN

Hohenheim University, Section of Fermentation Technology, Research Distillery

STARGEN Fermentation time: 3h

Hohenheim University, Section of Fermentation Technology, Research Distillery

STARGEN Fermentation time: 3h

Hohenheim University, Section of Fermentation Technology, Research Distillery

STARGEN Fermentation time: 21h

Hohenheim University, Section of Fermentation Technology, Research Distillery

STARGEN Fermentation time: 21h

Hohenheim University, Section of Fermentation Technology, Research Distillery

STARGEN Fermentation time: 69h

Hohenheim University, Section of Fermentation Technology, Research Distillery

Contents of Extract and Ethanol During Fermentation Hohenheim Process

0

5

10

15

20

25

30

0 20 40 60 80 100Time (h)

Extra

ct (%

mas

)

0

2

4

6

8

10

12

Etha

nol (

%m

as)

Extrakt Alkohol

Hohenheim University, Section of Fermentation Technology, Research Distillery

STARGEN Process: "Extract Contents" from different mashes

0

2

4

6

8

10

12

3 21 21 24 27 68 69

Time h

Con

tent

g/L

GlycerolLactic acidDP3DP2DP1

Hohenheim University, Section of Fermentation Technology, Research Distillery

Ethanol Yield from Triticale Using Different Enzyme Systems

36

37

38

39

40

41

42

43

44

Genencor Hohenheim StargenEnzymes

LA /

100

kg G

rain

Hohenheim University, Section of Fermentation Technology, Research Distillery

STARGEN Process

• Maximum temperature 59°C• Simultaneous starch degradation from native

granules , saccharification and fermentation• It should be possible to finish fermentation

within 60 h ( max 10%vol EtOH )• Fermentation was free from infections without

problems although we used a traditional yeast mash

• Low temperature and viscosities lead to energy savings in cooling (water), pumping, stirring.....

Hohenheim University, Section of Fermentation Technology, Research Distillery

Thank You Very Muchfor

Your Attention