Thermal processing of biomass into high-calorific solid composite fuel

- Technology of thermal processing biomass into a solid composite fuel is developed.
- Liquid products after thermal processing and dextrin were used as a binder.
- The greatest strength of the fuel is achieved by adding dextrin of 5% by weight.
- Drying temperature should not exceed 80 °С for pellets and 40 °С for fuel briquettes.
- Solid composite fuel has calorific value of 29.1 MJ/kg (chips) and 20.9 MJ/kg (peat).

Since the reserves of fossil fuels are gradually exhausting, the biomass inclusion in the energy balance is becoming an urgent issue and a major field for researchers. However, such biomass characteristics as high moisture content, low calorific value, friability, stickiness and others lead to the high operating costs for burning. Thus, biomass pre-processing is required to improve its properties. This work shows the results obtained through the development and substantiation of the parameters of the biomass processing technology in a high-calorie solid fuel for boiler units. Chips from a mixture of Siberian wood (birch, pine, and aspen) and peat of Kandinsky deposit were used as biomass sources. Thermal processing (low-temperature pyrolysis) allows increasing the calorific value of the updated raw materials and obtaining the basis for the binder. Liquid pyrolysis products together with dextrin were used for molding solid composite fuel in the form of pellets and briquettes. These solid fuels had lower heating values of 29.1 MJ/kg (wood chips) and 20.9 MJ/kg (peat), which is superior to most types of fuel briquettes and pellets and comparable to the highest-quality fossil fuels.