超细粉在导向管喷动床中的流化行为

以料径5μm的CaCO3超细粉为物料，对其在半圆形导向管喷动床中的流化行为进行研究，考察床层压降特性及喷嘴直径、导喷距及导向管直径对起始流化行为的影响。     

循环喷动流化床固体循环速率的控制

通过研究操作条件对固体循环速率的影响 ,提出了新型的固体循环速率的双阀控制理论模型 ,基于循环喷动流化床中颗粒循环推动力的分析 ,得出了预测循环喷动流化床中固体循环速率最大值的方法     

导向管喷流床的最小喷动速度的研究

在内径９２ｍｍ的有机玻璃床内,使用四种没的物料,以空气作为喷动相流气体,综合考虑了床层的几何尺寸,以及气体和固体本身的物性,研究了导向管喷流床的最小喷动速度,得出了导向管喷流床的最小喷动速度的经验公式,以便对其设计和操作提供参考     

增压导向式喷动流化床固体颗粒循环速率的关联

实验考察了喷动气速度、流化气速度、压力以及颗粒尺寸对增压导向式喷动流化床固体颗粒循环速率的影响规律,并归纳出关联式,为正在开发的第二代增压流化床联合循环发电系统(2GPFBC–CC)中关键部件—炭化炉的放大设计提供了帮助.     

导向管喷动流化床电极的研究

本文以半床形矩形导向管喷动流化床电极为研究对象,以直径0.45mm的铜颗粒为阴极颗粒,研究了电流密度、喷动液流量对浓度为1g/L的稀CuSO4溶液电解过程的影响。研究结果表明:增加电流密度虽然可以增加电解初期铜离子的沉积速率,电流密度过大导致氢离子析出,铜回收率和电流效率将下降;喷动液流量增加,可以有效消除颗粒表面的浓度分布层,减小传质阻力,增加铜离子沉积速率,喷动液流量过大,铜颗粒在环隙区停留时间减小,铜离子在颗粒表面放电反应减弱,导致铜离子沉积速率降低。在电流密度为6.24A/m2,喷动液流量为80 L/h条件下,电解120min,回收率到达99.74﹪,电流效率大于30﹪,铜离子浓度为2.65 mg/L。     

导向充气喷动床的临界充气速度

１前言在普通喷动床的环形区底部额外引入一股辅助气体,由于喷动气体和辅助气体各自独立地改变,气固系统将出现下列几种体系或操作状态：①固定床;②充气喷动床;③喷流床;④带射流的流化床。长期以来对充气喷动床与喷流床的区别不是很清楚的［１～５］。张怀清等［６...     

导向管喷动床床层与埋管表面的换热特性研究

以石英砂作为循环颗粒,研究了颗粒与换热管束壁面的换热特性.在导向管喷动床环隙内,砂子以移动床的形式向下移动.为测定移动床层与埋管表面的换热系数,自制了组合热探头,并用调压器调节组合热探头的功率,使其稳定在不同温度下工作.分别考察了不同电压、不同吹松气量和不同床层轴向位置等对换热系数的影响.通过电压递增与递减的验证性实验,考察了两种方式对实验结果的影响.通过实验可知,换热系数随颗粒循环量的增加而增加.实验在常温常压下进行,喷动床材质为有机玻璃,移动床层与埋管换热壁面的平均换热系数在300 W/(m2·K-1)～400W/(m2·K-1)之间.     

导向管液固喷动床的数值模拟研究

本文以液-固两相流理论为基础,用颗粒动力学理论描述颗粒与颗粒间的碰撞,用标准湍流方程模拟液相和颗粒相的湍动,并且考虑液-固两相的相互作用,旨在探索一种工程设计和放大的新方法。对比颗粒循环速率和密相区真实液相流速的模拟结果与实验值,结果吻合较好。     

导向管充气喷动床流体力学性能

在内径92mm的有机玻璃床内,对导向管充气喷动床的操作相图、床层压降、最小喷动速度及最大弃气速度进行了研究.实验采用4种颗粒为实验物料并采用空气为 喷动和弃气气体,通过对实验数据的回归得到用于计算或判别导向管弃气喷动床最小喷动速度和最大充气速度的计算式,以便为其设计和操作提供依据.     

导向管喷动流化床内颗粒停留时间模型

通过对导向管喷动流化床的喷动区和流化区分别进行质量平衡和动量平衡,得出了描述连续流动条件下其床层内粒子停留时间的数学模型。本模型所得计算结果与以前报道的实验结果一致。     

循环喷动流化床固体流动规律

<正>循环喷动流化床由于循环管(导向管)的引入,显著地提高了射流床的操作能力、传热传质特性及接触效率,因而被广泛地应用于化工过程,如:颗粒涂层、煤气化和石油烃类的热裂解)。 鉴于循环喷动流化床的广泛应用,许多研究者对床层的气固流动循性进行了研究,但是由于实验的几何参数、特性参数及操作参数的不同,实验结果存在着较大的差异,有关固体循环速率的数学模型报道很少,已有的模型也因假设条件太多及考虑影响因素不全而不具有普遍的适用性,本文通过研究几何参数、操作参数及物性参数对固体循环速率的影响,进而得出综合考虑以上参数在内的预测固体循环速率的定量方程,为工程设计提供重要信息。     

SOLIDS CIRCULATION IN SPOUTED AND SPOUT-FLUID BEDS WITH DRAFT-TUBES

A 20 cm semi-cylindrical spout-fluid bed with a draft-tube has been used to investigate the effect of various physical parameters on the solids circulation rate, A new method has been developed by which these data can be easily and accurately collected. Equations are presented which can be used to predict the maximum attainable solids circulation rate and the spouting velocity required to achieve this maximum for the unit operating in spouting mode. The circulation trends are shown to be a direct result of the phenomena of entrainment and jetting occurring in the entrainment zone investigated visually with a video camera. Preliminary gas bypassing experiments were also performed which show the ability to almost eliminate spout gas bypassing to the annulus with appropriate auxiliary gas addition.     

PREDICTION OF SOLIDS CIRCULATION RATE IN THE RISER OF AN INTERNALLY CIRCULATING FLUIDIZED BED (ICFB)

A predictive mathematical model based on pressure drop in the riser of an Internally Circulating Fluidized Bed (ICFB) is developed to predict solids circulation rate (Gs). The values of G_s predicted using the model agree well with the experimental data. The model also predicts well G_s at higher operating temperatures in the riser of an ICFB.     

PREDICTION OF SOLIDS CIRCULATION RATE IN THE RISER OF AN INTERNALLY CIRCULATING FLUIDIZED BED (ICFB)

A predictive mathematical model based on pressure drop in the riser of an Internally Circulating Fluidized Bed (ICFB) is developed to predict solids circulation rate (Gs). The values of G_s predicted using the model agree well with the experimental data. The model also predicts well G_s at higher operating temperatures in the riser of an ICFB.     

ANALYSIS OF FLUID DYNAMICS IN A SPOUTED BED WITH CONTINUOUS SOLIDS FEEDING

ABSTRACT

An experimental study was carried out on Quid dynamics and solids movement in a modified spouted bed with the feeding of particles through the base, at different air rates, panicle feed rates and bed heights. Moreover, a model was adapted for the base-feed configuration, and results of its numerical resolution were compared with experimental data. Analysis showed that the modeling of the bed is complex due to a lack of knowledge of fundamental spout parameters, such as the fluid-particle drag coefficient. Air velocities in the spout were predicted by the model with a maximum deviation of 15%, whereas prediction of particle velocities in the spout yielded maximum deviations of 50%.     

狭缝式矩形喷动床中多粒度颗粒体系的最大喷动压降

在 15 0 mm× 5 0 mm× 110 0 mm的矩形喷动床中 ,研究了单一粒径体系和二组分及三组分混合粒径颗粒体系的最大喷动压降受颗粒粒径及粒度组成、静止床高和气体入口狭缝宽度的影响情况。实验采用宽度为2、4、6 mm三种宽度的狭缝式气体分布板 ,实验物料为单一粒径分别为 1、1.5、2 mm的玻璃珠。实验表明矩形喷动床的最大喷动压降与上述三种影响因素都有关系。本文还给出了最大喷动压降随这三种因素变化的实验关联式