(13d) Technoeconomic Analysis of Pyrolysis of Forest Residues

Because of its simplicity, fast pyrolysis is an attractive biomass conversion process which is scalable from mobile units to thousands of tons per day.  However, the utility of the oils produced by fast pyrolysis is limited because of the well-known chemical and physical properties of these highly oxygenated oils.  It is possible to improve the quality of the oils by employing catalysts in the pyrolysis reactor and by performing downstream hydrodeoxygenation with additional catalysts and hydrogen.  It is important to understand the effects these additional processes have on the technoeconomics and ability to do distributed processing.  Also, biomass feedstock composition significantly affects the product distributions and, therefore, the thermal integration within the process. 

As the most heavily forested state in the country, Maine has a large pulp and paper industry.  Along with the 12 million green tons of pulpwood which are harvested annually,[1] there is likely the potential to collect an equal quantity of associated biomass (residues) if a suitable conversion technology and product market were to exist.  These residues, which consist of tree tops, limbs, stumps and bark, have a higher percentage of lignin and ash than round-wood chips.  This talk will present results of a technoeconmic analysis based on Aspen simulations and data from pyrolysis of forest residues.  The pyrolysis oil is simulated using a set of model compounds which can be optimized for different oil products based on weighted parameters such as higher heating value, CHO ratios and chemical functionality.

¹2010 Wood Processor Report, Department of Conservation, Maine Forest Service, Forest Policy and Management Division www.maine.gov/doc/mfs/pubs/pdf/wdproc/10wdproc.pdf .