Biomass conversion methods

1. Torrefaction

• Definition: Mild pyrolysis process (200–300°C) in absence of oxygen.

• Purpose: Upgrades biomass into a solid bio-coal with higher energy density, hydrophobicity, and grindability.

• Environment: Inert/limited oxygen atmosphere.

• Products:

  • Main: Solid (torrefied biomass, ~70% mass retained, ~90% energy retained).

  • Minor gases & volatiles released.

• Applications:

  • Pre-treatment of biomass for co-firing with coal.

  • Easier storage, transport, and handling.

2. Pyrolysis

• Definition: Thermal decomposition of organic material at 350–700°C in absence of oxygen.

• Purpose: Breaks down biomass/coal into liquid, solid, and gas products.

• Environment: No oxygen (strictly anaerobic).

• Products:

  • Bio-oil (pyrolysis oil) → liquid fuel.

  • Char (solid carbon-rich residue).

  • Syngas (CO, H₂, CH₄, CO₂).

• Applications:

  • Production of biofuels, chemicals, activated carbon.

  • Waste-to-energy conversion.

3. Gasification

• Definition: Partial oxidation of carbonaceous feedstock at 800–1200°C with controlled amount of oxygen/steam/air.

• Purpose: Converts solid feed into syngas (CO + H₂).

• Environment: Sub-stoichiometric oxygen (not enough for full combustion).

• Products:

  • Main: Syngas (CO, H₂).

  • By-products: CO₂, H₂S, tar, slag/ash.

• Applications:

  • Power generation (IGCC).

  • Feedstock for methanol, ammonia, hydrogen.

  • Coal-to-liquids and chemicals.

Key Differences