Fast pyrolysis, biomass

This pretreatment enhances the energy density of wood by increasing its carbon content and net caloric value and is therefore expected to become more important in the future, especially as a treatment preceding gasification (feedstock moisture content should be <20-30%).Torrefied material is more brittle than the feedstock wood material and it has intermediate characteristics between coal and the feedstock. In case of fast pyrolysis, biomass should normally be dried to about 10% moisture content, since a considerable amount of reaction water is also formed (about 25% of feedstock) during this process. 

Large-scale gasification reactor technology based on EF gasification from (a) General Electric (GE Texaco process) and (b) Conoco-Phillips (E-Gas). (Adapted from Meier, D. Faix, O. Fast pyrolysis A route for energy and chemicals from wood—fluidized vs. ablative pyrolysis. In Wood and Biomass Utilization for the Carbon Uptake, Seoul National University, Seoul, 2005, pp. 55-68.)... 

Research activities in the area of fast pyrolysis of biomass started toward the end of the 1970s of past century. A thorough overview of the basic principles and actual state of the art is given by Meier,96 Bridgwater and Peacocke,97 and Mohan et al.98... 

Bridgwater, A. V. Peacocke, G. V. C., Fast pyrolysis processes for biomass. Renewable and Sustainable Energy Reviews 2000, 4,1-73. 

Bridgwater, A. V., Principles and practise of biomass fast pyrolysis processes for liquids. Journal of Analytical and Applied Pyrolysis 1999, 51, 3. 

BioTherm A System for Continuous Quality, Fast Pyrolysis BioOil, Dynamotive Energy Systems Corporation, 4th Biomass Conference of the Americas, Oakland, California, September 1, 1999... 

Another approach to produce chemicals via degraded molecules is the fast pyrolysis of biomass at high temperatures in the absence of oxygen. This gives gas, tar and up to 80 wt.% of a so-called bio-oil liquid phase, which is a mixture of hundreds molecules. Some of compounds produced by pyrolysis have been identified as fragments of the basic components of biomass, viz. lignin, cellulose and hemicellulose. The bio-oil composition depends upon the nature of starting... 

The present chapter discusses aspects, known by the authors, of (a) biomass as feedstock, (b) the concept of bio-refinery, (c) thermochemical routes from lignocellulosic biomass to fuels, and (d) the contribution of catalytic technology. The main focus will be on the catalytic conversion of fast pyrolysis oil into fuels with regard to problems encountered currently and the challenges for future research and development. 

The literature on biomass fast pyrolysis is quite extensive and excellent research and technology reviews are available [51-55]. For an optimal fast pyrolysis process in terms of organic liquid yield the temperature is around 500 °C the biomass particle size should be small (<5 mm). 

Fast pyrolysis oil has almost the same elemental composition as the biomass itself hence it can be seen as a kind of liquid wood. It can be transported, can be pressurized and processed more easily than solid biomass. One of the major difficulties in the catalytic conversion of solid biomass is achieving effident con-tad between the heterogeneous catalyst (which is most of the times a solid) and the biomass itself. In this context, bio-oil provides more options for easier catalytic conversion. However, pyrolysis is a very complex and the oil is a difficult to handle chemical mixture. Complete vaporization, for instance, is not possible because part of the components start to decompose and polymerize upon heating... 

Fast pyrolysis processes for biomass, Renewable Sustainable Energy Rev., 2000,... 

Czemik, S., Bridgwater, A.V., Overview of application of biomass fast pyrolysis oil, Energy Fuels, 2004, 18, 590. 

Scott, D.S., Majerski, P., Piskorz, J., Radlein, D., A second look at fast pyrolysis of biomass - the RTI process,... 

M. Mann, E. Chorlet, in Hydrogen production via catalytic steam reforming of fast pyrolysis oil fractions. Proceedings of the 3ri Biomass Conference of the Americas, Pergamon, Oxford, 1997, p. 845. 

Pyrolysis dates back to at least ancient Egyptian times, when tar for caulking boats and certain embalming agents were made by pyrolysis. In the 1980s, researchers found that the pyrolysis liquid yield could be increased using fast pyrolysis where a biomass feedstock is heated at a rapid rate and the vapors produced also condensed rapidly (Mohan et al., 2006). 

Fast pyrolysis utilizes biomass to produce a product that is used both as an energy source and a feedstock for chemical production. Considerable efforts have been made to convert wood biomass to hquid fuels and chemicals since the oil cri-... 

Chomet, E. 2001. Biomass to hydrogen via fast pyrolysis and catalytic steam reforming. Proceedings of the 2001 USA. DOE Hydrogen Program Review (NREL/CP 570-30535). 

Gercel, H.F. 2002. The effect of a sweeping gas flow rate on the fast pyrolysis of biomass. Energy Sources 24 633-642. 

Li, S., Xu, S., Liu, S., Yang, C., Lu, Q. 2004. Fast pyrolysis of biomass in free-fall reactor for hydrogen-rich gas. Fuel Proc Technol 85 1201-1211. 

Putun, A.E. 2002. Biomass to bio-oil via fast pyrolysis of cotton straw and stalk. Energy Sources 24 275-285. 

Wang, D., Czernik, S., Chornet, E. 1998. Production of hydrogen from biomass by catalytic steam reforming of fast pyrolysis oils. Energy Fuels 12 19-24. 

Shafizadeh F., In Proceedings of the Specialists Workshop on Fast Pyrolysis of Biomass, SERI/CP-622-1096, (1980). 

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