The paper discusses the various applications of FTIR absorption spectroscopy as a tool for characterizing waste biofuels for pyrolysis and gasification. The FTIR spectrometer used in the study allows for analysis of solid and liquid waste and biofuel samples. Further, an
attached dedicated gas cell is used in the characterization of gases evolving during pyrolysis in a versatile pyrolyser/gasifier attached to the FTIR. The pyrolyser operates in a batch mode and generates large quantities of product samples suitable for further chemical and
physical analysis. The paper presents the preliminary results from investigation of the pyrolysis gases from three different biofuels: pure cotton, wood and fuel made from a mixture of biomass and plastics (ROFIRE®). First, certain characteristic classes of components are identified in the gas, and second, an attempt is made to explain the origin of the gas components based on the known chemical constituents of the waste/biofuel.