AUTOTHERMAL UPGRADING OF BIOMASS AND WASTE FUELS FOR EFFICIENT GENERATION OF HEAT AND POWER

摘要

In the present paper, it was demonstrated that main technical and economical barriers of co-combustion of coal and alternative fuels for efficient production of heat and power may be significantly reduced or eliminated by drying and carbonization of the alternative fuels during low temperature thermolysis process. The authors developed and constructed a novel reactor, in which the whole process of fuel drying and carbonization is conducted autothermally. To run the reactor no external energy for the thermolysis is required, since the heat required to run the process is obtained directly from exothermic reactions, as well as from combustion of the flue gases produced due to thermal treatment of the input fuels. Thermal treatment of the alternative fuels in the reactor brings about: 1/ increase of the product LHV compared to the LHV of the input fuel, as well as 2/ removal of unwanted byproducts, which are difficult & too expensive to get rid from the flue gases 'produced' due to direct co-combustion. The process final products are: 1/ solid residue (biocarbon) and 2/ hot flue gases. Direct use of the biocarbon for power production does not require installation of any additional fuel handling or preparation systems. Furthermore, combustion of biocarbon brings about no decrease of the boiler efficiency, since the moisture content in the biocarbon is negligible and independent from initial fuel moisture.