METHOD FOR TREATING BIOMASS

摘要

A method for treating biomass, in which method the biomass is dried in a process in which an essential part of the dried biomass is recycled (35) back to be mixed (31) to the biomass coming into the process, is characterized in that one or more enzymes or mixture of enzymes including at least cellulase are added into the biomass in the drying process whereby the process parameters and the enzymes or mixtures of enzymes are selected in such a way that the temperature and holding time at the temperature are favourable for the action of the enzymes, and that the recycling and the addition of the enzymes are arranged so that enzymes are added into the biomass on the average several times during the treating process. The same circumstances suit well for both drying and efficient treatment with e.g. cellulase. The recycling of the biomass is advantageous for both drying and enzyme treatment. The treated biomass in which cellulose is to large extent decomposed is suitable for various purposes.