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Table 2 Summary of process conditions and efficiencies used in current models and other studies

From: Impact of pretreatment and downstream processing technologies on economics and energy in cellulosic ethanol production

 

Parameters

Dilute Acid

Hot Water

Dilute Alkali

Steam Explosion

  

Present Study

Laser et al. [30]

Aden et al. [19]

Kazi et al. [29]

Eggeman and Elander[31]

Present Study

Kazi et al. [29]

Eggeman and Elander[31]

Present Study

Present Study

Biomass

Biomass

Tall Fescue

Switchgrass

Corn Stover

Corn Stover

Corn Stover

Tall Fescue

Corn Stover

Corn Stover

Tall Fescue

Tall Fescue

Biomass Processing

Feedstock Rate (dry Mg/day)

704.5

4535

2000

2000

2000

704.5

2000

2000

704.5

704.5

Pretreatment

Temperature (°C)

180

190

190

190

140

180

190

180

180

180

 

Pressure (bar)

11

12.3

12.3

11.8

-

11

12.5

 

11

11

 

Residence Time (min)

15

2

2

2

-

15

5

5

15

15

 

Solid Loading (%)

20

30

30

29.6

-

20

12.9

13.9

20

30

 

Acid/Alkali Concentration (%)

1

1.1

1.1

1.9

1

0

0

 

1

-

 

Cellulose + 0.111 H2O→ 1.111 Glucose (%)

13.04

6.5

7

6.3

8c

0.43

0.32

4.5c

0.29

5

 

Xylans + 0.136 H2O → 1.136 Xylose (%)

60.26

85

90

82.5

90.2c

70

2.39

50.8c

0.72

70

 

Lignin → Soluble Lignin (%)

5

5

5

10

-

5

5

 

25

5

 

Xylose → 0.64 Furfural + 0.36 H2O (%)

5

5a

5a

10a

-

2.5

0a

-

0.01

15

 

Glucose → 0.7 HMF + 0.3 H2O (%)

5

-

-

3b

-

2.5

0b

 

0.01

15

Hydrolysis

and

Fermentation

Bioconversion Method

SSCoFd

SSFe

SSCoF

SSCoF

-

SSCoF

SSCoF

 

SSCoF

SSCoF

 

Temperature (°C)

35

37

65 (Sacchaarification)

41 (Co-fermentation)

32

-

35

32

 

35

35

 

Enzyme Loading (FPU/g cellulose)

15

15

12

18f

15

15

18f

15

15

15

 

Time (Saccharification + Fermentation) (days)

5

7

3 (1.5 + 1.5)

7 (5+2)

-

5

7 (5+2)

 

5

5

 

Cellulose + 0.111 H2O→ 1.111 Glucose

79

80

90

91.09

83.8c

78.5

89.97

90c

84.75

70

 

Xylans + 0.136 H2O → 1.136 Xylose (%)

80

80

-

57.13

55.1c

80

56.6

64.63c

80

80

 

Glucose → 0.489 CO2 + 0.511 Ethanol (%)

95

90

95

95

 

95

95

 

95

95

 

Xylose → 0.489 CO2 + 0.511 Ethanol (%)

70

90

85

75.6

 

70

75.6

 

70

70

 

Cellulase → 0.1 Protein Soluble + 0.9 water (%)

99

-

-

-

-

99

-

-

99

99

Ethanol Recovery

Ethanol Recovery (%)

98.76

98.8

98.9

-

-

98.76

-

-

98.76

98.76

  1. a Percentage conversion of xylans to furfural
  2. b Percentage conversion of cellulose to furfural
  3. c The efficiencies are based on cumulative sugars (oligomers+monomers)
  4. d SSCoF - Simultaneous saccharification and Co-fermentation
  5. e SSF - Simultaneous saccharification and fermentation
  6. f 31.3 mg protein/g cellulose (600 FPU/g protein)