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1.
负压差移动床立管料斗架拱实验研究   总被引:1,自引:0,他引:1  
通过测量散体颗粒在负压差移动床立管料斗中静态拱宽度及分析散体性质、料斗形状和操作条件对料斗静态拱宽度的影响,得出当散体颗粒643.5kg/m3≤ρb≤1085kg/m326.7°≤θr≤32.9°22.4°≤δ≤34.6°在负压差移动床立管的锥形料斗0°<α≤28.1°中形成静态拱时,其宽度可以通过下面的关联式求得:DcalDs=0.238θrδ0.158α-0.272(-dp/dh)ρbg0.388  相似文献   

2.
通过测量散体颗粒在负压差移动床立管料斗中静态拱宽度及分析散体性质,料斗形状和操作条件对料斗静态拱宽度的影响,得出当散体颗粒643.5kg/m^3≤ρb≤1085kg/m^3 26.7°≤θr≤32.9° 22.4°≤δ≤34.6°在负压差移动床立管的锥形料斗0°〈α≤28.1°中形成静态时,其宽度可以通过下面的关联式坟得:(Dcal/Ds)=0.238(θr/δ)^0.158(α/Φ)^-0.27  相似文献   

3.
根据Geldart-A类散体颗粒在移动床充气条件下气体均匀分布的特点,结合散体力学和两相流理论,提出理论模型并导出散体颗粒的无约束屈服强度与静态拱宽度的关系式,通过实验测量在负压差条件下与移动床立管联接的料斗中Geldart-A类散体颗粒的静态拱宽度来计算其无约束屈服强度.对于Geldart-A类散体颗粒,此方法的测量结果比Jenike测量结果能更准确地描述散体颗粒的无约束屈服强度.  相似文献   

4.
负压差料斗中静态架拱机理实验研究   总被引:3,自引:0,他引:3       下载免费PDF全文
景山  李洪钟 《化工学报》1997,48(5):560-570
通过实验测量散体颗粒在负压差立管料斗中的静态拱宽度,验证本文模型的正确性,并分析了散体颗粒的无约束屈服强度、料斗形状、操作条件和延时效应对静态拱宽度的影响,提出负压差移动床立管料斗孔口最小直径的理论预测方法.  相似文献   

5.
立管移动床气固流动相图及理想料封状态   总被引:5,自引:0,他引:5  
李洪钟 《化学工程》1989,17(5):28-34
本文通过对立管移动床气固流动规律的研究和归纳,绘制了立管移动床气固流动相图。相图展示了有可能出现的13种移动床操作状态及其相互依存和转化的条件,对其中的理想料封状态的性质、存在条件和应用价值进行了专门的讨论。  相似文献   

6.
高温气体脱硫除尘一体化过程研究   总被引:4,自引:2,他引:2  
高温气体净化是新一代煤基发电技术的关键问题.简要分析了高温气体脱硫除尘一体化过程中,脱硫和除尘过程的操作特点和相互影响,并比较了固定床、移动床、流化床、气流床和表面过滤器联合工艺的优缺点,指出移动床是最适于高温气体脱硫除尘一体化的装置.应加强工艺基础研究.  相似文献   

7.
负压差移动床的气-固流动   总被引:5,自引:1,他引:4       下载免费PDF全文
本文研究了在负压差条件下,立管移动床中的气体流动特性,没有气体通过时的理想料封状态,以及固体流动速率。根据三种物料四种规格的试验结果,得出了综合关系式;并讨论了移动床的气-固流动,提出合理选择与设计移动床料封高度的方法。  相似文献   

8.
张瑞超  赵朔  白鹏 《现代化工》2013,(11):119-122
对模拟移动床的操作方式进行分类并且介绍其在国内外研究的进展,针对模拟移动床的结构设计、模型建立和优化方法进行系统的阐述,并展望了模拟移动床色谱技术的研究趋势。  相似文献   

9.
吴献东  金晓明  苏宏业 《化工学报》2007,58(8):2038-2044
多目标优化策略被应用于模拟移动床过程的操作优化中,采用一种基于Pareto最优解的多目标优化算法——NSGA-Ⅱ算法,以分离联萘酚对映体的模拟移动床色谱分离过程作为研究对象,利用模拟移动床TMB数学模型,以分离性能指标作为目标函数进行了多目标操作优化设计。优化结果表明,NSGA-Ⅱ算法得到的非劣解在目标空间分布均匀,算法收敛性和鲁棒性好。基于NSGA-Ⅱ算法的面向分离性能多目标优化设计方法为模拟移动床分离过程的工艺设计和操作指导提供了有效的工具。  相似文献   

10.
非平衡循环吸附色谱分离研究   总被引:3,自引:1,他引:2       下载免费PDF全文
李忠  舒文利 《化工学报》1998,49(4):501-505
引言制备或大型液相色谱因在温和条件下具有高分辨分离能力且操作简单而广泛应用于药物、生物化学品和碳氢化合物等的分离和高纯化.其应用的范围和规模正在不断发展.然而,传统的吸附色谱因其吸附剂利用率低,生产效率低.为克服这一缺陷,Wankat,Barker和Ganetsos以及Ruthven和Ching等人比较了各种逆流、错流和模拟移动床色谱分离技术和原理,提出各种柱组合分离的方法.模拟移动床色谱能获得较高生产效率,但其设备和操作较复杂,一定程度上限制了它的应用.循环色谱是一种新颖的分离技术,这一概念最早是由Bombaugh和Biesenberger…  相似文献   

11.
彭威  刘艳升  韩胜贤  黄炳庆 《化工进展》2020,39(8):2947-2953
再生立管是FCC装置再生器和提升管反应器之间再生催化剂循环的输送管,其操作复杂性在于立管内催化剂的流态受多种因素影响。本文中在1.0Mt/a FCC装置上,通过测量立管改造前后不同操作条件时的轴向压力分布,考察再生立管输送催化剂的影响因素。生产运行结果表明,影响立管操作的主要因素包括催化剂密度和平均粒径、立管几何结构、滑阀安装位置、松动风性质和流量等;选用低密度催化剂和高黏度流化介质可以减小气泡尺寸,维持反应温度稳定;松动风流量应根据立管推动力、滑阀压降和反应温度及时调整,避免填充流。另外,立管结构和滑阀的安装位置对立管推动力影响较大,分析结果可供立管设计和装置改造参考。  相似文献   

12.
A stress distribution model for a liquid-solid circulating moving bed reactor that consists of a bottom reaction chamber, a top regeneration chamber, a coupling standpipe, a particle transportation system, and a bottom standpipe is established based on the equations of continuity and momentum balance. Simulations show that the stress concentration regions are at the bottom of the regeneration chamber and the coupling standpipe. To reduce the maximal stress and increase the operation flexibility in a reactor for the 2000-ton-per-year production of linear alkylbenzene, the regeneration chamber should have a low height-to-radius ratio (about 9), a suitable half-conical angle between 28° and 35°, and standpipe radius of about 0.05 m.  相似文献   

13.
A stress distribution model for a liquid-solid circulating moving bed reactor that consists of a bottom reaction chamber, a top regeneration chamber, a coupling standpipe, a particle transportation system, and a bottom standpipe is established based on the equations of continuity and momentum balance. Simulations show that the stress concentration regions are at the bottom of the regeneration chamber and the coupling standpipe. To reduce the maximal stress and increase the operation flexibility in a reactor for the 2000-ton-per-year production of linear alkylbenzene, the regeneration chamber should have a low height-to-radius ratio (about 9), a suitable half-conical angle between 28° and 35°, and standpipe radius of about 0.05 m.  相似文献   

14.
A quantitative criterion distinguishing stable from unstable transitional packed bed flow in standpipes is presented. This criterion can be used as an working guideline in actual standpipe operation. A fundamental and simple model based on stress free surface (SFS) theory has been developed. This model also provides a quantitative prediction method for the standpipe voidage.  相似文献   

15.
In this paper, the literature on standpipe flow is systematically reviewed. In particular, four possible flow regimes are defined, viz. dense phase fluidized solids flow (DENFLO), lean phase fluidized solids flow (LEANFLO), transition packed bed flow (TRANPACFLO) and packed bed flow (PACFLO). The possibilities of coexistence of more than one of these flow regimes and the prediction of these coexistences are discussed. Available equations pertaining to each flow regime and to flow of gas—solids mixture through a slide valve are summarized. The use of the equations for analysis of industrial standpipe operation is illustrated by means of two case studies. Finally, areas where further work would be fruitful are pinpointed. More experimental work is urged to verify the validity of some of the equations presented and to improve our understanding of the different types of flow instabilities in standpipe operation.  相似文献   

16.
负压差立管气固流动的不稳定性实验分析   总被引:12,自引:2,他引:10  
负压差立管内气固两相流具有流动的不稳定性,比较典型的是颗粒流量的不稳定性. 实验表明这种不稳定性主要有两种形式,一种是流量偏移,流量从一个值逐渐或突然转变为另一个值,这种现象一般发生在立管的入口或出口,是颗粒失流化架桥产生的;另一种是流量振荡,流量在一定的范围内发生波动变化,即低频脉动流动,这是颗粒逆压力梯度流动压缩气体造成的. 负压差立管气固流动的不稳定性对工艺过程的运行具有潜在的危害性.  相似文献   

17.
The standpipe has become a standard element of most circulation loops. In the past, standpipes have been thought of as a device to only allow solids to transfer from a low to a higher-pressure region. However, it also has another function in a solids circulation loop. It is also the device that adjusts its operation to balance the pressure around the solids circulation loop. An overflow standpipe adjusts the pressure drop across it by raising or lowering the solids level in the standpipe. However, the operation of the underflow standpipe is more complex. This self-adjusting function can cause underflow standpipe pressure drops to be negative, which seems counter-intuitive. How an underflow standpipe operating with a negative pressure build can occur in a circulation loop is described below using two commercial unit examples as illustrations of this phenomenon.  相似文献   

18.
General two-phase theory is applied to the flow of gas-solid mixtures in standpipes. It is shown that at a fixed flow rate both fluidized bed flow and packed bed flow can coexist in the same standpipe. Matsen's analysis of standpipe flow is extended and a general method for determining flow pattern and gas entrainment rate in standpipe flow is described. Data from a commercial standpipe in a fluid bed catalytic cracking unit are analysed. The analysis shows that fluidized bed flow occurs in the standpipe in support of Matsen's work on standpipe flow in another fluid bed catalytic cracking system.Flow instability, in standpipe is discussed in the light of this work and a mechanism of flow instability based on transition in flow pattern is postulated.  相似文献   

19.
在循环流化床(CFB)煤燃烧/热解双反应器冷态实验装置上,以硅胶和电厂锅炉灰为实验物料,考察了立管内的气固流动特性,其中立管的内径44mm、高3m。研究结果表明,立管内的气固流动形态为移动床流动,Leung的立管流动模型适合对该系统中立管内移动床流动的描述,经拟合分别得到了立管内气、同速率以及气同相对速率与固体速率之间的经验方程,对热态实验过程中判断立管内的气固流动型态以及料封的稳定性均具有一定的参考价值。  相似文献   

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