Can Coal be Replaced with Biomass Briquettes?
India’s natural coal reserves are estimated to last another century and yet, coal shortage and fluctuating prices pose a threat to our country’s energy security. According to an article published by Business Standard, India is likely to face a supply shortage of about 42 million tons of coal in the third quarter of 2022. This is due to higher power demand and lower mine output this year.
India is an agricultural country with huge untapped potential for using agricultural waste as biomass for producing biofuels to replace conventional fuels such as coal and petroleum. Solid biofuels, such as briquettes and pellets, are considered carbon-neutral and used in industrial boilers, which typically run on coal.
Can biofuels produced from agricultural waste be the new coal? How do they compare in terms of efficiency and cost? Read the article to find out.
How are Biofuels Produced from Agri-waste Briquetting?
Briquettes and pellets are made by compressing biomass material under high pressure and converting them into blocks of various uniform sizes and shapes. These are energy-dense and burn with little or no smoke depending upon the type of biomass used in making them.
The process of briquetting converts loose biomass sourced from various crop residues, agro-waste, and industrial raw biowaste into dense energy-rich bricks of uniform shape and sizes. Briquettes burn without emitting smoke, so they are also known as white coal or biocoal.
The calorific value of solid biofuels, such as briquettes, varies depending upon the type of biomass used in the manufacturing process. The various type of raw organic waste used in briquette and pellet making include (but are not limited to):
● Sugarcane Bagasse
● Wood chips, shavings, sawdust
● Groundnut and Cashew Seed shells
● Rice husk and paddy straw
● Coir dust
● Wheat straw
● Sunflower waste
The calorific value of quality briquettes is substantially higher than loose biomass and is slightly lower in comparison to coal. However, there may be exceptions.
How do Briquettes and Pellets Compare with Coal?
1. Calorific Value
Calorific value is a measure of the amount of heat generated from the combustion of a specific quantity of a substance. The calorific value of coal ranges between 25–35 MJ/kg. Anthracite has the highest calorific value among different types of coal. The calorific value of high-quality briquettes ranges between 18 and 24 MJ/kg.
A Comparison of Essential Quality Parameters of Common Biomass Commodities
Commodity | Commodity Residue | GCV (Kcal/kg) | Moisture (%weight) | Ash (%weight) |
|---|---|---|---|---|
Wood | Saw Dust | 4025 | 8 | 4 |
Groundnut | Shell | 4108 | 8 | 7 |
Soyabean | Husk | 4000 | 7 | 4 |
Groundnut and Wood | Shell/ Saw Dust | 3813 | 10 | 9 |
Sugar cane and Wood | Bagasse/ Saw Dust | 3830 | 10 | 9 |
Sugar cane and Wood | Trash/ Saw Dust | 3657 | 10 | 11 |
Sugar cane and Coffee | Trash/ Husk | 3754 | 10 | 10 |
Corn | Cob | 3511 |