Slow pyrolysis process parameters

There are numerous refeieitces that include chemical analyses of fast pyrolysis liquids from a variety of sources, including slow pyrolysis tar, fast pyrolysis liquid and fractions thereof. As fast pyrolysis liquid may be raw, treated, filtered, catalytically derived, upgraded and dependent on the process parameters, a "worst case" must be taken for the liquid compositioii, i.e. high variability. As noted, fast pyrolysis liquid falls within Class 3, based on its physical properties, however, this is further complicated by the presence of other chemicals that are in Class 6.1 - Toxic substances [phenols, etc.] which ate in concentrations above 0.1 wt%. A typical analysis of several fast pyrolysis liquids from different laboratories is given in Table 2. 

The effect of the physical characteristics of wood on slow pyrolysis or carbonization has thus been quite extensively studied. However, these studies focus mainly on the qualitative effects of the physical parameters of the material. The optimization of the carbonization process as operated by charcoal producers around the world requires quantitative relations, particularly regarding mass and energy flows as determining operational parameters of a dynamic process such as carbonization. 

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