Tham khảo tài liệu 'progress in biomass and bioenergy production part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Preparation and Characterization of Bio-Oil from Biomass 199 Fig. 1. The experimental device Zheng et al. 2006 As a kind of most popular and ideal configuration we have reason to believe that fluid bed will achieve greater developments in performance and cost reduction in the near future A. V. Bridgwater Peacocke 2000 . Temperature of reaction Fast pyrolysis is a high temperature process thus temperature has tremendous effect to the yield of liquid. The correlation between them is shown in Figure 2 for typical products from fast pyrolysis of wood Toft 1996 . In the lower temperature the liquid yield is low due to the less sufficient pyrolysis reaction which will produce high content of char at the same time. Likewise the excessive temperature will also lead to liquid yield decreased resulting from the increase of gas product. Reaction temperature C Fig. 2. Typical yields of organic liquid reaction water gas and char from fast pyrolysis of wood wt on dry feed basis Toft 1996 200 Progress in Biomass and Bioenergy Production In order to achieve high liquid yield the pyrolysis reaction temperature is better to controlled around 500C in the vapour phase for most forms of woody biomass A. V. Bridgwater et al. 1999b . Of course different crops may have different maxima yield at different temperatures. Vapour residence time Vapour residence time is also important to the liquid yield of pyrolysis reaction. Very short residence times will lead to the incomplete depolymerisation of the lignin while prolonged residence times can cause further cracking of the primary products A. V. Bridgwater et al. 1999b . Too long or short residence time will reduce the organic yield so it is necessary to select a suitable residence time. In general the typically vapour residence time is about 1 s. Liquids collection The collection of liquids has been a major difficulty in the preparation of fast pyrolysis processes because the nature of the liquid product is mostly in the .
