tailieunhanh - Progress in Biomass and Bioenergy Production Part 3

Tham khảo tài liệu 'progress in biomass and bioenergy production part 3', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Thermal Plasma Gasification of Biomass 49 Reactor gas temperature K Fig. 9. Gasification rate of wood particles in dependence on reactor temperature for various particle diameters It can be seen that the particle diameter substantially influences both the surface temperature and the gasification rate. Increase of the diameter results in reduction of heat transfer to the particle due to more intensive shielding of the particle by gas sheath formed from volatilized material. From the dependence of process rate on the size of particles a relation between throughput and minimum volume of the reactor can be estimated. The relation between total volume of particles of given diameter and gasification rate can be calculated from the equations 10 - 14 . In Fig. 10 the ratio of total volume of particles to material throughput is plotted in dependence on reactor temperature for several particle diameters. A minimum reactor volume needed for given material throughput can be determined from these dependences assuming that reactor volume should be several times Reactor gas temperature 0C Fig. 10. Ratio of volume occupied by particles to total gasification rate 50 Progress in Biomass and Bioenergy Production higher than volume occupied by particles to ensure good heat transfer to the particles. It can be seen from the Fig. 10 that needed volume of reactor rapidly increases with the size of the particles. The increase of the reactor volume leads to the increase of power loss Preact Tr in equation 4 . Optimal reactor volume can be determined on the basis of analysis of relations between process rate and power loss for given size of the particles. 4. Gasification of organic materials in steam plasma Plasma gasification of biomass was studied in the recent years in several papers Tang 2005 Brothier 2007 Hrabovsky 2006 Tu Wen Kai 2008 Tang 2005 Xiun 2005 . Up to now only laboratory scale experimental investigations of plasma biomass gasification have been performed. Production of .