An important biomass characteristic to be gasified is moisture, as a result of this, there may be some problems that can provide different features to the synthesis gas. A biomass with a high moisture content requires additional heat in the evaporation stage. This high moisture content reduces the temperature of the gasification causing an incomplete cracking of hydrocarbons generated after the pyrolysis step. The amount of inorganic components and ash contents are important parameters, particularly when gasification occurs at high temperatures. The most significant difference in the analysis of biomass and coal refers to the volatile content, since this value is high for the biomass (70-85%) on coal (20-25%).
This work presents an overview of typical yields found in the pyrolysis processes and that serve to define correlations that will be used in a gasification process, as part of the initial stage of the process simulation. Using a simulation Aspen PlusTM, platform, based on ultimate and proximate characterization of biomass, a pyrolysis unit was modeled to a fixed bed reactor and fluidized bed, inserting correlations that allow to find the main pyrolysis products as coal, tar and gases, as well as an ultimate and proximate characterizations of tar and coal.