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Torrefied Pellets Made from Bana Grass

By:Evan Wang
Position:Managing Director
Aug 04, 2025
In January 2024, SIMEC imported three tons of bana grass from Australia. Using the original biomass, SIMEC researchers have already conducted about 50 times of biomass leaching, biomass pyrolysis, pelleting and briquetting experiments. The range of thermochemical treatments covers from 200℃ (low temperature) to 750℃ (high temperature). Multiple degrees of biomass torrefaction and carbonization were tested. SIMEC research programs serve decarbonisation projects in the aluminium refinery industry, and coal mining industry.
 
It is very important that bana grass can be harvested 3-4 times a year, and the supply is sustainable.
As a fast-growing plant, bana grass is proved to be very premium raw material for the production of
bio-coal, due to its high compositions of lignin and cellulose. The mass conversion ratio is higher than many biomasses. This has been verified by multiple experiments and analyses conducted by SIMEC researchers.
pyrolyzed-rice-husk
 
rice-husk-char
 
By scientifically controlling the degree of thermal decomposition of hemicellulose, lignin and cellulose, the mass loss of bana grass torrefaction process can be minimized. Weight loss at 200℃ and below is attributed to loss of remaining bound and unbound moisture. But weight loss at 200 - 300 ℃ is mainly due to devolatization of organics when the hemicellulose starts to breakdown by bond breakage. During bana grass torrefaction, hemicellulose is mostly decomposed as it is active within the range of 200 - 300 ℃.

There are three important phases involved in the bana grass torrefaction process.
1. The first phase mainly consists of free and bound water extraction from biomass at 100-200 ℃.
2. The second phase is irreversible biomass degradation that occurs from 200 to 250 ℃.
3. The third phase, which occurs between about 250 and 330 ℃, usually involves the total destruction of hemicelluloses, the most reactive component of lignocellulose.

From dry bana grass to torrefied biomass, the conversion rate can be 75%-80%. The torrefied bana grass presents a dark brownish color. The grindability of torrefied biomass is significantly improved comparing with raw biomass fibers. Torrefied bana grass stalks are fragile and can be crushed easily even by hand.
pyrolyzed-rice-husk
 
rice-husk-char
 
Maintaining most of the lignin content and almost all of the cellulose, the pelleting process of torrefied banagrass is proved to be very successful. This benefits to maximize the energy density of torrefied pellets, and to minimize the mass loss caused by torrefaction.

The following table is an analysis result for torrefied banagrass pellets, with the serial number KL250722.
Moisture
Mt %		 Ash Content
Ad %		 Volatile Matter Content
Vad %		 Fixed Carbon Content
Fcad %		 Sulfur
St,d %		 High Heating Value
Qgrad Cal/g		 Low Heating Value
Qnetv Cal/g
2.05 4.51 71.52 23.94 0.11 5004 4731
 
The volatiles released during the biomass torrefaction process can be recovered to sustain the thermochemical reaction, and the excess heat will be used to dry the raw biomass. Adopting SIMEC’s advanced technology, a banagrass torrefaction and pelleting plant is self-sustained and automatic.
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