Pyrolysis, slow characteristics

Bio-oil from rapid pyrolysis is usually a dark brown, free-flowing liquid having a distinctive smoky odor. It has significantly different physical and chemical properties compared to the liquid from slow pyrolysis processes, which is more like a tar. Bio-oils are multicomponent mixtures comprised of different size molecules derived primarily from depolymerization and fragmentation reactions of the three key biomass building blocks cellulose, hemicellulose, and lignin. Therefore, the elemental composition of biooil resembles that of biomass rather than that of petroleum oils. Basic properties of biooils are shown in Table 33.7. More detail on fuel-related characteristics is provided in the literature.571... 

Table 10.6 PE slow pyrolysis (dynamic method) characteristic parameters...

Effect of Four Physical Characteristics of Wood on Mass and Energy Flows from Slow Pyrolysis in Retorts... 

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. 

Moreover, polymers 6 and 8 were pyrolyzed in bulk. These pyrolysis experiments were performed in a slow stream of nitrogen and the samples were heated to 1000°C at a rate of 10°C min", remaining at this temperature for 30 minutes Both of the ceramic products were black powders and in X-ray powder diffraction studies they showed only broad peaks of low intensity, indicating the presence of mainly amorphous material To obtain crystalline materials, the ceramic products were heated slowly to 1400°C where they were held for 5 hours. The X-ray powder diffraction showed exclusively sharp peaks, characteristic of P-SiC, respectively. The increased ceramic yield obtained by pyrolysis of the metal modified carbosilane 8, as compared with the polycarbosilane 6, can be explained by an increased concentration of carbon as impurity, which was additionally evidenced by elemental analysis. 

Trans-1,4-polybutadiene was chlorinated at room temperature chlorine analysis of the product gave nearly the theoretical amount of chlorine. A brief comparison of these polymers showed that the thermal stability of the H-H PVC was slightly lower than that of H-T PVC at 107°C. Additional studies of the chlorination showed that trans and cis-polybutadiene in chloroform at low concentration proceeded rapidly and in few minutes but the reaction slowed down when 50% chlorination had been achieved. It was then suggested that the normal chlorination reaction went fast but that the substitution reaction which became important at the end of the reaction is somewhat slower. Additional work on the chlorination showed that the samples of polybutadiene were either not fully defined or that the 1,4 content which is most important for the characteristic of pure H-H PVC was not quantitative and the polymers had from 2 to 6% 1,2 structures. Nevertheless, such studies as degradation, pyrolysis, GC, solution characteristics of the polymers, for example, molecular... 

In this study, an attempt was given to produce bio-oil through slow pyrolysis of rice husk (RH) at different heating rates in order to determine the optimum reaction condition that will give maximum liquid yield. The characteristics of bio-oil produced at different heating rates are then analyzed. Apart from that, the properties of bio-oil that was produced at optimum operating condition are compared with those in literature. 

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