Page 204 - Biomass Gasification, Pyrolysis And Torrefaction Practical Design and Theory
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Chapter | 6 Tar Production and Destruction 181
25
Yield of condensible liquids (kg/100 kg dry wood) 15
20
10
5
0
0 200 400 600 800 1000 1200 1400
Temperature (°C)
FIGURE 6.1 Effect of maximum gasification temperature on the range of tar yield. Source:
From Baker et al. (1988).
1
Principle component score 0.6
0.8
0.4
0.2
0
500 550 600 650 700 750 800 850 900 950 1000
Temperature (°C)
Primary Secondary Tertiary-Alkyl Tertiary-PNA
FIGURE 6.2 Variation of primary, secondary and tertiary tar products with temperature for
0.3 s residence time. Source: From Evans and Milne (1997), p. 807.
6.2.3 Tar Composition
As we can see in Table 6.3, tar is a mixture of various hydrocarbons. It may
also contain oxygen-containing compounds, derivatives of phenol, guaiacol,
veratrol, syringol, free fatty acids, and esters of fatty acids (Razvigorova
et al., 1994). The yield and composition of tar depend on the reaction
