C4 Torrefaction of Biomass

Question 1

concept torrefaction

Answer 1

biomass → torrefaction (remove hemicellulose) → torrified biomass (lignin + cellulose) + other product (liquid,solid,gas)

temp= 200-300 °C, cannot exceed 300°C

Question 2

objective torrefaction

Answer 2

• remove hemicellulose via thermal degradation of biopolymer
• ↑ C content, ↓ O & H content
• produce lighter structure- easy to transport

Question 3

why 200-300 °C, cannot exceed 300°C

Answer 3

• hemicellulose degrade at 225-300 °C
• cellulose degrade at 305-375 °C
• lignin degrade at 250-500 °C

Question 4

parameter affecting torrefaction

4 types

Answer 4

1. temperature
2. residence time
3. biomass type
4. feed size

Question 5

parameter affecting torrefaction

temperature

Answer 5

↑ temp, ↓ torrified biomass yeild, (more cellulose + lignin)

Question 6

parameter affecting torrefaction

residence time

Answer 6

↓ heating rate, ↑ residence time, ↓ mass yeild, ↑ energy density

Question 7

parameter affecting torrefaction

biomass type

Answer 7

• biomass with ↑ hemicellulose degrade faster
• xylan influence torrefaction - ↑ reactive, degrade faster

Question 8

degree of torrefaction

3 degrees

Answer 8

1. light torrefation (T=200-240), only hemicellulose degrade
2. medium torrefaction (T=240-260) hemicellulose degrade, cellulose mildly affacted
3. severe torrefaction (T=260-300) hemicellulose,cellulose,liginin degrade forming char

Question 9

physical properties of torrified biomass

Answer 9

1. density
2. grindability
3. hydrophobicity
4. explosion potential of torrified dust
5. densification & pallestitation