ANDRITZ Belt drying system BDS

Biomass drying - necessary pretreatment for further processes

ANDRITZ supplies the complete process, not only for sludge treatment, but also for biomass drying - from wet milling to drying, fine milling and pelleting, all from a single source.


The world’s largest belt dryers for biomass, with eight meters belt width, in Lauterbach, Germany

3D model of the biomass dryer for Joutseno mill, Finland

Why biomass drying?

In most cases, biomass (wood bark, woodchips, sawdust, and energy chips) have to be dried before being used in pelleting, briquetting, incineration, and gasification. By reducing the biomass water content to 10-15%, its calorific value is increased from 2 kWh/kg to approximately 4.5 kWh/kg. This cuts the transport and storage costs, as well as creating ideal conditions for direct firing or optimum pelletizing properties, both for industrial and high-grade wood pellets. As a result of the drying process, less fuel input is required to generate energy, which also reduces the pollutant emissions caused by the combustion system.

Dryer selection criteria

  • Flexibility in processing different biomass qualities and mixtures
  • Use of various energy sources, including waste heat
  • Low energy consumption
  • Low emissions (dust, VOCs, exhaust gases)
  • High safety standards (fire/explosion protection, interlocks, etc.)

ANDRITZ belt dryer for biomass - once-through, hybrid, or closed-loop type for low-value heat

  • Hot water (70-120° C)
  • LP steam
  • Flue gases
  • Thermal oil

Other biomass dryers

Rotary drum dryer for high-value heat sources:

  • Forgiving characteristics
  • Air recirculation giving low oxygen content and low energy consumption
  • Simple operation

Pneumatic dryer for pulverized firing:

  • High final dryness, exceeding 96%
  • High degree of milling - small particle size and clear cut-off

Fluid bed dryer for particulate and granulate material:

  • With or without in-bed heat exchanger
  • Drying and cooling

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