Method for the thermal treatment of biomass in connection with a boiler plant

摘要

The invention relates to the improvement of the fuel-properties of biomass in an integrated manner to facilitate storage, shipping and applicability thereof. In the process, biomass (6) is thermally treated within a combustion process to cause partial torrefaction of the organic matter present in biomass, thus yielding components inert to biological decomposition processes. Constituents (10) separated in gaseous form are utilized as fuel, while the thermally treated biomass (8) remaining in the solid form is utilized in a separate process.

主权项

1. A process for the thermal treatment of biomass in connection with a boiler plant, comprising the steps of
feeding biomass to a torrefaction reactor where the biomass is heated to a temperature between 180 and 350° C. under conditions with low oxygen concentration, thus causing at least partial torrefaction of organic matter present in the biomass to produce components which are inert with respect to biological decomposition processes, said thermal treatment thus resulting in gaseous reaction products and torrefied biomass, passing the gaseous reaction products generated by the thermal treatment from the torrefaction reactor to a power plant boiler, and passing hot flue gas from the power plant boiler to the torrefaction reactor to carry out the thermal treatment,wherein more than 80% of the energy content of the fuel burned in the power plant boiler originates from a main fuel other than gaseous reaction products generated in the torrefaction reactor, and
the heat treatment of the biomass is performed in a continuous torrefaction reactor, in which the flue gas stream flows at least partially in the same direction as the biomass.