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Table 2 Comparison of steam explosion pretreatment studies for softwood

From: Pilot-scale steam explosion pretreatment with 2-naphthol to overcome high softwood recalcitrance

References

Stages

Additive/catalyst

T/°C

t/min

Feedstock

Washing after pret.

FPU g−1 cellulose

Glucose EH/%

Mannose EH/%

Glucose P/%

Mannose P/%

Total sugar/%

 

1

–

235

5

Spruce chips <30 mm

No

15

31

0

7

32

36

30

45

2

46

60

58

3

63

 

1

2-Naphthol admixed

235

5

Spruce chips <30 mm

No

15

44

4

8

35

48

30

67

2

63

60

86

13

80

 

1

2-Naphthol, acetone imp.

235

5

Spruce chips <30 mm

No

15

67

1

5

16

55

30

93

2

70

60

98

2

73

 

1

2-Naphthol, ethanol imp.

235

5

Spruce chips <30 mm

No

15

81

1

3

12

64

30

95

2

74

 

60

95

5

75

Ballesteros et al. [46]

1

–

210

4

Pine chips 8–12 mm

Yes

32

32

  

60

41

Fang et al. [38]

1

H2SO a4

200

 

Spruce chips 1–20 mm

Yes

39

26

 

5

10

42

Stenberg et al. [11, 52]

1

SO b2

210

5.5

Spruce chips 2.2–10 mm

Yes

30

58

 

13

52

66

Tengborg et al. [11, 48]

1

H2SO c4

210

1

Spruce chips <30 mm

Yes

30

39

 

33

55

67

Monavari et al. [47]

1

SO d2

200

20

Spruce chips 5–6 mm

Yes

28

51

7

15

78

71

Nguyen et al. [50]

1

H2SO e4

215

1.7

Fir + Pine chips <12.7 mm

Yes

60

50

 

30

65

75

Söderström et al. [11, 51]

2

H2SO f4

180/200

10/2

Spruce sawdust

Yes

30

36

 

41

96

77

Söderström et al. [11, 55]

2

SO g2

190/220

2/5

Spruce chips 2.2–10 mm

Yes

30

45

 

35

95

80

Nguyen et al. [50]

2

H2SO h4

180/210

4/1.5

Fir + Pine chips <12.7 mm

Yes

60

25

 

57

84

82

  1. Shown are the conditions for the highest total sugar yield. Yields are expressed as % of the raw biomass content
  2. EH yield in enzymatic hydrolysis (accounting for cellulose recovery from pretreatment), P yield in pretreatment liquor, Mannose hemicellulosic sugars excluding glucose
  3. aImpregnated with 0.6% w/w H2SO4 based on wood dry matter
  4. bImpregnated with 3.5% w/w gaseous SO2 based on wood dry matter
  5. c2.4% w/w H2SO4 in pretreatment liquid
  6. dImpregnated with 2.5% w/w gaseous SO2 based on water moisture
  7. e0.43% w/w H2SO4 in pretreatment liquid
  8. f1st stage: impregnated with 0.5% w/w H2SO4 based on wood moisture; 2nd stage: impregnated with 2% w/w H2SO4 based on wood moisture
  9. gImpregnated with 3% w/w gaseous SO2 based on wood moisture
  10. h1st stage: 0.43% w/w H2SO4 in pretreatment liquid; 2nd stage: 2.5% w/w H2SO4 in pretreatment liquid