Biomass is the most effective and alternative energy source on the earth. It contains moisture content from 50 to over 150%. So they must be dried to enhance energy product quality, energy efficiency, and to lower the emissions during the energy conversion. Greenwood biomass in its fresh form typically contains moisture up to 50 to 55 percent. Biomass needs to be dried well for efficient burning, and also to minimize the storage as well as handling process.
Drying biomass fuel offer significant benefits to the combustion boilers, mainly for lower air emissions, enhanced boiler operations, and improved boiler efficiency. Efficient drying ensures the best quality biomass conversion efficiency and better net mass. It also makes the dry biomass easy to transport it to the bio-refineries. Rotary drum dryer is the most common one for drying biomass waste.
It is less sensitive to the material size, and many farmers and agriculturists are using these machines for drying the grains, nuts, vegetables, beans, herbs, animal feeds, woody biomass, agricultural wastes, and more. In fact, its use enhances the efficiency of the drying process of biomass pellets. The moisture content in raw biomass is usually 30 to 60 percent. So the usage of the rotary drum dryer maximizes the combustion efficiency and control.
The rotary dryer machine has a low maintenance cost, robust construction, and high flexibility, handle the wide range of materials and run under the most critical conditions. Another essential benefit of the rotary dryer is that they run at high temperature, less prone to the size to the size of dried sawdust, less drying time and are simple to install.
Application in Wood Pellets Drying:
Wood pellet is the kind of biomass fuel commonly used to generate heat, power and combined energy in electricity, heating, and micro combined cooling systems. Wood bio-fuels are mainly vital in the countries with high forest resources. The rotary drum dryer is also used to dry the wood residue in the wood pellets to maximize its efficiency. These machines help to combine the wood bark, chips, and wet sawdust with the warm air inside an insulated rotating drum.
Firstly, the material is crushed to get a more uniform particle size followed by drying of the material. Then the material is placed into the mold to generate pellets and forced to pass via it, creating small cylindrical shaped fuel pellets. The lignin binds the particles to each other under the high temperature and pressure. These pellets have a high bulk density and moisture content around 7 to 8 percent. The best part of the rotary drum dryer is that they accept a broad range of particle sizes and lower the moisture content of wood from 60 percent to 15%.
