Skip to main content

Table 4 Comparison of hydrothermal/chemical pretreatment followed by mechanical refining and hydrothermal/chemical pretreatment alone or mechanical refining alone

From: Promise of combined hydrothermal/chemical and mechanical refining for pretreatment of woody and herbaceous biomass

Sample

Pretreatmenta

Milling energy (kWh/ton)b, c

Sugar yield (%)d

Reference

Hardwood chips

Sodium carbonate

NAe

42.11 (total sugar)

[53]

Sodium carbonate + PFI milling

360–1800

46.90–53.12 (total sugar)

Sodium carbonate + disk milling (12 inch diameter)

698

69.51 (total sugar)

Sodium carbonate + disk milling (42 inch diameter)

67–147

62.48–66.51 (total sugar)

Japanese cedar

Ozonolysis

NA

28–68 (glucose)

[54]

Disk milling

4167–26,389

29–44 (xylose)

Ozonolysis + disk milling

8333–22,222

38–75 (glucose)

  

26–45 (xylose)

71–94 (glucose)

44–59 (xylose)

Lodgepole pine trees

Disk milling

615.9

11.3 (glucose)

[52]

Hot water (initial pH 5.0) + disk milling

537.0

33.1 (glucose)

Acid (initial pH 1.1) + disk milling

335.6

39.6 (glucose)

SPORL (initial pH 4.2) + disk milling

499.3

84.1 (glucose)

SPORL (initial pH 1.9) + disk milling

134.5

92.2 (glucose)

Eucalypt chips

Disk milling

990

72.94 (total sugar)

[65]

Sodium hydroxide impregnation + disk milling

630

80.77 (total sugar)

Magnesium hydroxide impregnation + disk milling

430

91.53 (total sugar)

Hinoki cypress eucalyptus chips

Disk milling

853

50 (glucose)

[73]

Steam treatment + disk milling

744–1489

96.8 (glucose)

Eucalyptus chips

Disk milling

408

45 (glucose)

Steam treatment + disk milling

192–458

98.4 (glucose)

Eucalyptus chips

Hot water

NA

50 (glucose)

[55]

Hot water + disk milling

167

101.7 (glucose)

Eucalyptus chips

Hot water

NA

3.1–65.2 (total sugar)

[37]

Hot water + ball milling

1436

45.6–66.7 (total sugar)

Rice straw

Hot water

NA

97.5 (glucose)

[62]

Hot water + mechanical refining

250–583

97.3–99.5 (glucose)

Oil palm mesocarp fiber

Disk milling

5250

30.2 (glucose)

[56]

Superheated steam + disk milling

1417–3028

30.6 (xylose)

Hot water + disk milling

4083–4972

26.0–47.8 (glucose)

  

24.1–42.1 (xylose)

46.3–91.1 (glucose)

10.1–54.3 (xylose)

Corn stover

Alkali deacetylation + disk milling (36 inch diameter)

128–468

85.9–91.7 (glucose)

[42]

81.1–86.2 (xylose)

Sugarcane bagasse

Alkaline + disk milling

11,111

77 (glucose)

[63]

67 (xylose)

Sugarcane bagasse

Hot water

NA

72.1–78.7 (total sugar)

[75]

Hot water + PFI refining

 

82.1–87.2 (total sugar)

Wheat straw

Hot water

NA

28.1–72.4 (total sugar)

[59]

Hot water + PFI refining

 

28.3–75.5 (total sugar)

Oil palm mesocarp fiber

Ball milling

NRf

7.3–10.3 (glucose)

[38]

Alkaline

 

12.2–14.9 (xylose)

Alkaline + ball milling

 

39.6–63.9 (glucose)

  

21.1–46.5 (xylose)

97.3 (glucose)

 

63.2 (xylose)

Corn stover

Acid impregnation + dilute acid

NA

69–73 (glucose)

[58]

Alkali deacetylation + acid impregnation + dilute acid

 

55–58 (xylose)

Acid impregnation + dilute acid + PFI refining

 

80–83 (glucose)

Alkali deacetylation + acid impregnation + dilute acid + PFI refining

 

76–80 (xylose)

  

85 (glucose)

75 (xylose)

90 (glucose)

92 (xylose)

Corn stover

Alkali deacetylation + acid impregnation + steam explosion + PFI refining

NR

79–83 (glucose)

[49]

Alkali deacetylation + acid impregnation + steam explosion + extruder

 

50–55 (xylose)

Alkali deacetylation + acid impregnation + steam explosion + food processor/blending

 

82–83 (glucose)

Alkali deacetylation + acid impregnation + steam explosion + disk milling (12 inch)

 

56–58 (xylose)

Alkali deacetylation + acid impregnation + dilute acid (pilot-scale)

 

71–75 (glucose)

Alkali deacetylation + acid impregnation + dilute acid pretreatment (pilot-scale) + Szego milling

 

49–51 (xylose)

  

75–78 (glucose)

52–54 (xylose)

82 (glucose)

80 (xylose)

90–95 (glucose)

85–90 (xylose)

Eucalyptus chips

Hot water

NA

73.19 (glucose)

[72]

Hot water + disk milling

 

90.45 (xylose)

  

91.62 (glucose)

88.12 (xylose)

Rice straw

Disk milling

NR

86 (glucose)

[60]

Hot water + disk milling

 

40 (xylose)

  

110 (glucose)

84 (xylose)

  1. aHot compressed water, hydrothermal and autohydrolysis are named as hot water
  2. bWhen energy consumption was presented as kJ/ton, it was converted into kWh/ton
  3. cEnergy consumption is only from mechanical refining
  4. dIf the exact sugar yields were not indicated in the reports, sugar yields were estimated or calculated as the ratio of the amount of monosaccharides produced during hydrolysis to the corresponding carbohydrate concentrations in the original samples
  5. eNA means not applicable
  6. fNR means not reported