Why in News?

• India is planning to make use of the Swedish torrefaction technology to reduce stubble burning issue.

What Is Torrefaction?

• Biomass torrefaction is a thermal process used to produce high-grade solid biofuels from various streams of woody biomass or agro residues.
• The end product is a stable, homogeneous, high quality solid biofuel with far greater energy density and calorific value than the original feedstock, providing significant benefits in logistics, handling and storage, as well as opening up a wide range of potential uses.

How it Functions?

• Biomass torrefaction involves heating the biomass to temperatures between 250 and 300 degrees Celsius in a low-oxygen atmosphere.
• When biomass is heated at such temperatures, the moisture evaporates and various low-calorific components (volatiles) contained in the biomass are driven out.
• During this process the Hemi-Cellulose in the biomass decomposes, which transforms the biomass from a fibrous low-quality fuel into a product with excellent fuel characteristics.
• To make a biomass torrefaction plant economically viable it is crucial to use the energy “lost” in the volatiles. This can be done by burning the volatiles (torgas) in a lean gas combustor. This combustor can provide the heat for the drying and torrefaction also.

Possible Benefits of the Technology:

• Torrefaction of biomass results in a high grade biofuel which can be used as a replacement of coal in electricity and heat production and as input for gasification processes in the production of high value bio-based fuels and chemicals.
• The Torrefied pellets becomes an ideal coal replacement because of its following features:
• Grinds & burns like coal – Existing Infrastructure Can be used
• Lower Feedstock Costs
• Lower shipping and Transport Costs
• Minimal de-rating of the Power Plant
• Provides Non-Intermittent Renewable Energy
• Lower sulphur and Ash Content (compared with coal)