Commissioned by a customer in Indonesia, SIMEC R&D engineers conducted a verification experiment of torrefaction process that converts wood pellet to black pellets, and carried out laboratory analysis. The purpose of this experiment was to study the changes in the physical and chemical properties of wood pellets before and after torrefaction.
Introduction to experimental methods:

1. Raw material preparation: import a sample of wood pellets made of sengon and mahoni wood sawdust mix, original in Indonesia.

2. Equipment selection: use laboratory scale SIMEC AP-SFB reactor which is specially designed to torrefy wood pellets. Both the torrefaction temperature and residence time are controllable. The technology provides the opportunity to torrefy “white” biomass pellets directly with minimal dust and small particles, thus safeguarding the quality of torrefied “black” pellets to meet international standard.

3. Setting of torrefaction parameters. The sample of wood pellets are directly fed into the torrefaction reactor without any treatment.

4. Data logging: During the pellet torrefaction process, SIMEC AP-SFB reactor system will monitor key parameters (e.g., temperature, time, pressure), record and analyze mass change, color and shape change, etc.

5. Lab test and analysis of torrefied black pellets, such as heating value, color, hardness, shape, etc. The test indicates that mechanical hardness of torrefied black pellets is the same with white pellets.

6. Hydrophobic feature test of torrefied black pellets.
 

At 2:21 p.m. on October 19, 2024, 5 torrefied black pellets were soaked in water, and by 6:05 p.m. on the same day, about 4 hours, the black pellets did not appear to absorb water and swell, the color remained unchanged, and the mechanical hardness did not change. By 8:46 a.m. on October 21, after soaking in water for 42 hours and 25 minutes, the black pellets still did not appear to absorb water and swell, and the color and mechanical hardness remained unchanged.

Conclusion: white wood pellets can be converted to be qualified black pellets through SIMEC torrefaction technology.