With the abundant straw available, large scale straw pellets production are possible. And now straw pellets technology is widely utilized and straw pellet mill machines are available globally which makes straw pellets are popular for heat and power production.
1.Raw materials preparation：Straws usually has a high potential of dust, which is affected by the way of harvesting. Thus, straw needs to be screened from contaminants, such as, dust that may influence straw pellet quality and other alien materials, such as, stones, metals, and those that may damage the pellet mill in the following procedures.
2.Grinding: Straw biomass is a tube-like or pipe-like material with a diameter of 4 to 8 mm, and wall thickness around 0.3-0.6mm. With the tube/pipe-like structure, straw can be easily processed by straw hammer mill and get the desire pellet size. Generally, the grinding of straws including cutting and chopping of the straws.
3.Drying: Usually, straw delivered in form of air-dried bale, with the moisture around 15%, which is the proper for straw pellet production. Therefore the drying of straw pellets is often by-passed. Even if drying is needed for straw pellet production, straw requires far less drying comparing with sawdust.
4.Conditioning: Straw requires special conditioning to achieve desirable hardness. Straw conditioning includes the application of steam(and /or water) and the addition of binding agents or additives. Conditioning is required to achieve the necessary temperature and moisture to get the malleability and to melt the lignin to act as binding agent. Binding agents are needed to strengthen the hardness of the pellets and also to decrease abrasion during pelletizing.
5.Pelletizing: During pelletizing, it is necessary to consider the factors such as, materials moisture content, density, pellet size, fiber strength, and the natural binder for they can influence the pellet quality.
The common problems during pelletizing of straw pellets are pellet die blocking and breakage, overheating, high energy costs or bad pellet quality and high maintain of the straw pellet making machine. To avoid of the mentioned problems, high quality pellet mill is needed. Generally speaking, straw requires a thicker pellet die comparing with that of sawdust to increase the compression length( the friction forces), to obtain a more favorable product quality.
6.Cooling and screening: Newly extruded straw pellets are hot and soft which needs to be cooled down to get a desirable hardness while at the same time fine pellets will be recycled.
Recommend some common biomass rice husk bamboo straw wood pellet production plants:
Forestry Waste Pellet Line:https://www.cn-pellet.com/solution/wood-pellet-production-line/forestry-waste-pellet-line.html
Waste Organic Matter Pellet Line:https://www.cn-pellet.com/solution/wood-pellet-production-line/waste-organic-matter-pellet-line.html
Agricultural Waste Pellet Line:https://www.cn-pellet.com/solution/wood-pellet-production-line/agricultural-waste-pellet-line.html
Wood Pellet Line:https://www.cn-pellet.com/solution/wood-pellet-production-line/wood-pellet-line.html
Grass Pellet Line:https://www.cn-pellet.com/solution/wood-pellet-production-line/grass-pellet-line.html
Palm Shell Pellet Line:https://www.cn-pellet.com/solution/wood-pellet-production-line/palm-shell-pellet-line.html
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