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81.
M. Sreekanth D. Ruben Sudhakar B.V.S.S.S. Prasad Ajit Kumar Kolar B. Leckner 《Fuel》2008,87(12):2698-2712
A two-dimensional model is developed for the determination of devolatilization time and char yield of cylindrical wood particles in a bubbling fluidized bed combustor. By using the concept of shape factor, the model is extended to particles of cuboid shape. The model prediction of the devolatilization time agrees with the measured data (present and those reported in the literature) for cylindrical and cuboidal shaped particles within ±20% while the char yield is predicted within ±17%. Influence of some important parameters namely, thermal diffusivity, external heat transfer coefficient and shrinkage, on the devolatilization time and char yield are studied. Thermal diffusivity shows noticeable influence on devolatilization time. The external heat transfer coefficient shows little influence beyond a value of 300 W/(m2 K). However particle shrinkage shows negligible effect on the devolatilization time but has a significant influence on the char yield. 相似文献
82.
83.
《Drying Technology》2008,26(3):308-314
A study has been conducted on the performance of a draft tube conical spouted bed for drying fine particles. Batch operation has been performed with nonporous, porous, and open-sided draft tubes in order to ascertain the optimum configuration of this internal device. The nonporous draft tube requires the lowest minimum spouting velocity. Nevertheless, the solid circulation rate and the drying efficiency of the open-sided draft tube are superior to any other spouted bed configuration. Moreover, it allows for reducing the height of the fountain and, consequently, the height of the drying equipment. 相似文献
84.
The objective of this study is to determine the chemical kinetics of desulphurization of Thai limestone in an atmospheric fluidized bed combustor (AFBC). The experiments, which employed the batch technique using the limestone samples from six major sources in Thailand, were performed in a laboratory‐scale AFBC. The results obtained were analysed and correlated in the form of apparent reaction rate and deactivation rate constants as a function of operating conditions of the furnace and their properties, respectively. The formulae derived from these correlations were kept as general as possible in order that they could be used as input parameters for the selected mathematical model of desulphurization in an AFBC that is suitable for practical use. The predicted results were in good agreement with the experimental data reported in the literature. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
85.
研究了钛铁矿选择氯化制取人造金红石反应的Fe-Ti-C-O2-Cl2系平衡图,计算了氧与某些氯化物相互作用的自由能变化,采用“通氧一步选择氯化法”,解决了选择氯化“自热”反应持续进行的技术关键,对反应参数进行了实验室,半工业和工业化生产试验研究,研究证明,选择氯化过程的动力学模型是“固体颗粒粒度保持不变的缩核反应模型”,动力学区的活性能为34.33kJ/mol;扩散区的活化能为0.80kJ/mol,研究开发的无筛板沸腾氯化炉可以长期稳定地连续运转,生产出的人造金红石品位为92.10%,经摇床和磁选,品位达到95%,床层单位炉产能达12.4t/(m2.d),该工艺和设备已成功地应用于工业生产。 相似文献
86.
本文对冰覆盖下的河道水流进行了区域划分,给出了区域分界面上的水流条件。应用水力学中的一些基本概念和基本原理,对冰覆盖下河道水流阻力、水流流速、切力、能坡及床面高程等问题进行了研究,给出了它们的物理概念和计算公式,并用实验观测资料进行了验证,结果令人满意。 相似文献
87.
88.
一度流超饱和输沙法是考虑了超饱和输沙特点的泥沙沉降计算方法.沉沙池内水流挟沙力是一定水力和床沙组成条件下水流挟带床沙质的能力.从已建沉沙池沉降标准、池内设计水流水力以及床沙组成条件来看,沉沙池运行前期、中期水流挟沙力一般都很小.用一度流趋饱和输沙法计算沉沙池沉降率时可不考虑水流换沙力的影响.均匀流条件下,用不考虑挟沙力和考虑挟沙力的一度流超饱和输沙法分别计算沉沙池的沉降率,二者相对误差取决于挟沙力与进口含沙量之比,该比值小于0.2时,相对误差小于20%.沉沙池内挟沙力与进口含沙量之比小于0.2时,用一度流趋饱和输沙法计算沉沙池的沉降率,可不考虑水流挟沙力的影响. 相似文献
89.
The thermal behaviour of a packed bed storage system charged with hot air is modelled using two partial differential equations representing the energy conservation in the air and solid phases constituting the bed. These two equations are coupled through the heat exchange process between the two phases. A fully implicit numerical scheme based on forward, upwind and central differencing for the time, first and second space derivatives, respectively, is used to solve the modelling equations. Marching technique is used for the air equation and a tri-diagonal matrix solver is employed to solve the solid equation. The solution yields the thermal structure of the bed, namely the air and solid temperature distribution inside the bed at any particular time, and the variation of total energy stored in the bed with time. The effect of bed length, solid diameter and void fraction on the thermal characteristics of the packed bed is studied. Further, the performance of the bed under variable inlet air temperature and mass flow rate is investigated. 相似文献
90.
A new catalyst loading method, in which catalyst particles are packed in a reactor with a novel internal, has been studied by measuring pressure drop, RTD, liquid holdup and mass transfer. It can be inferred from experimental results that the internal changes the conventional gas and liquid counter-current flow into a new cross-current flow, so the problems of excessive pressure drop and “flooding” are avoided. When pressure drop, liquid holdup, RTD and mass transfer coefficient are similar, the catalyst loading fraction of the new method is much higher than that of conventional methods. Furthermore, the reactive distillation reactor with the novel internal has advantages such as simple structure, low operating cost, and convenience for installation and removal of the catalyst. 相似文献