How to Turn Sawdust into Charcoal Using a hydraulic briquette maker？

Jan 19, 2026

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The core objective of wood chip pretreatment is to adjust the raw material to a state "suitable for briquetting and conducive to carbonization." This requires careful control of three key indicators: particle size, moisture content, and impurity removal. The standards for each indicator differ from those for wood pellet extruders, necessitating precise differentiation. Regarding particle size control, briquetting machines are suitable for wood chips of 2-8mm, which is more lenient than the 2-5mm requirement for wood pellet grinding machines. However, if the particle size exceeds 8mm, it will lead to uneven stress during briquetting, resulting in cracked finished products and a high breakage rate after carbonization. If the particle size is too fine (below 1mm), it will increase the extrusion resistance of the briquetting machine, exacerbating equipment wear, and also making coking more likely during carbonization. A small hammer mill can be used with a grading screen to ensure uniform particle size. Oversized particles should be re-crushed, while overly fine particles can be mixed with coarse particles to improve molding results.

Moisture content control is the core of hydraulic biomass briquette press pretreatment and is also the aspect that differs most significantly from wood pellet mills. The briquette carbonization process requires a sawdust moisture content of 8%-12%, while the optimal moisture content for homemade wood pellet presses is 12%-15%. If the moisture content is too high, the sawdust briquettes are prone to cracking and crumbling during pressing. Water evaporation during carbonization will also lead to excessively large pores and insufficient strength in the charcoal. If the moisture content is too low, the lignin will be difficult to soften, making briquette forming difficult and resulting in insufficient density in the finished product. When adjusting moisture, fresh, wet sawdust can be naturally air-dried (2-3 days, turning it 1-2 times daily) or treated with a small dryer (80-100℃). For dry sawdust, water should be sprayed evenly with a spray bottle while stirring to ensure uniform moisture distribution. The standard for judging this is that the sawdust should "clump together when squeezed in the hand, crumble easily when released, and leave no obvious water residue."

The impurity removal process for charcoal briquettes requires consistency with wood pellet processing equipment. Hard impurities in the sawdust must be thoroughly removed to avoid damaging the equipment and ensure charcoal quality. Common impurities in wood chips include stones, metal scraps, and twigs. These impurities can wear down the rollers and molds of the briquetting machine, reducing its lifespan. After carbonization, they may also remain in the charcoal, affecting its purity and selling price. To address this, a three-pronged approach can be used: manual sorting removes large impurities, a magnetic separator adsorbs metal scraps, and a grading screen filters out fine impurities, ensuring an impurity removal rate of over 99%.