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A novel approach for the integration of biomass pyrolytic conversion processes in existing markets of liquid fuels and chemicals


A novel approach for the integration of biomass pyrolytic conversion processes in existing markets of liquid fuels and chemicals. A bench scale biomass flash pyrolysis reactor has been developed in co-operation by AUA and CRES during previous EC projects. The main objective of the current project was to carry out further improvements as far as the CFB reactor stability, performance, product consistency, product characteristics and scale-up are concerned. More specifically work was performed and results were reported on the following: -Characterisation of biomass feedstock properties. -Pyrolysis experiments in the CFB reactor. -Modifications in the liquid and solids recovery equipment of the CFB reactor. -Experimentation on a laboratory scale plasma reactor and parametric studies on the pyrolysis liquids upgrading. -Design and construction of three cold flow models for derivation of scale-up rules. -Compilation of a techno-economic, environmental, and safety analysis for the pyrolytic process. The main conclusions of the project are summarized below: -Ready to feed feedstock availability is a crucial requirement for the successful outcome of any biomass-to-energy project. -The liquids yields achieved varied from 38 % wt maf feedstock for wheat straw at riser temperature 670 degrees Celsius, to 63.4 % wt maf feedstock for hardwood, at riser temperature 450 degrees Celsius. -Though fully upgraded pyrolysis oil with the new technique was not produced, the improvement of the oil characteristics cannot be overseen: An essential rise in the energy input leads to a clearly visible increase in pH value, water content and H/C value of the BCO. From the results of single compounds analysis it is assumed that the most significant effect is the destruction of acetic acid by the electrical discharge. -For further evaluation of the scaling criteria and validation of cold flow model results exploitation and operation of a CFB pyrolyzer pilot plant with approximately 100 kg/h biomass flow rate would be desirable. -Even though, most of the standard methods for the analysis of petroleum products can be used for BCO, it is crucial to modify existing standard methods or to develop new analytical methods. -The overall cost (including feedstock costs) of converting biomass to BCO with the current process is calculated to 45-56 ECU per GJ of delivered energy for a 1 ton/h plant, using pine as feedstock. Economies of scale will reduce these costs to 30-40 ECU per GJ for a 15 tons/h plant. In comparison heavy oil with a sulphur content of 3.5% costs range from 2 up to 4 1990 ECU per GJ of delivered energy.