首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 500 毫秒
1.
推导和建立了描述超临界流体萃取塔两相流体力学特性的数学模型。在Φ25mm连续逆流操作的超临界填料萃取塔、筛板萃取塔和喷淋萃取塔中,应用超临界二氧化碳-异丙醇-水、超临界二氧化碳-乙醇-水两种实验体系对流体力学模型进行了实验验证,计算结果与实验数据吻合较好。  相似文献   

2.
在内径为25mm的连续逆流超临界流体填料萃取塔中,对超临界CO2/异而醇/水和超临界CO2/乙醇/水两体系的流体力学特性进行了实验研究.实验用填料为金属板彼和金属丝网0环填料,实验压力为8~15MPa,温度为35℃.测定了塔内超临界流体相存留分数及流滴尺寸,并得到超临界流满直径服从正态分布的规律.  相似文献   

3.
超临界流体萃取塔传质性能的研究   总被引:2,自引:0,他引:2  
建立了描述连续逆流超临界流体萃取塔传质性能的数学模型。在直径为25mm连续逆流操作的超临界填料塔、筛板塔、喷淋塔中,应用超临界二氧化碳-异丙醇-水、超临界二氧化碳-乙醇-水两种实验体系对传质模型进行了实验验证,计算结果与本文实验数据符合较好。  相似文献   

4.
糠醛精制新型萃取塔的研究和应用   总被引:1,自引:0,他引:1  
在塔径为0.1m的自行开发的蜂窝型格栅(FG型)规整填料萃取塔中进行了两相流体力学行为和传质性能的实验研究,体系是具有低界面张力的正丁醇—丁二醇—水和中等界面张力的30%磷酸三丁酯(TBP)煤油溶液—乙酸—水,实验测定了液滴平均直径,分散相存留分数、两相液泛速度等参数及以每个理论板高度表示的传质特性。实验结果表明,这种新型萃取塔对中、低界面张力体系具有通量大、传质效率高等特点,尤其适合于糠醛精制润滑油体系。将其应用于新疆独山子炼油厂的糠醛精制转盘萃取塔的技术改造获得成功,取得了显著的经济效益。  相似文献   

5.
超临界流体萃取固态物料的缩芯萃取模型   总被引:7,自引:0,他引:7  
对超临界流本萃取固态物料进行了萃取机理分析,建立了超临界流体萃取固态物料的萃限模型,给出了宏观萃取速率表达式,提出了验证实验方案。  相似文献   

6.
共轭环填料萃取塔的流体力学性能研究   总被引:1,自引:0,他引:1  
在内径为120mm的共轭环填料萃取塔中,采用正丁醇-水-丁二酸作为实验体系,对其流体力学特性进行了研究。结果表明,在萃取过程中共轭环填料具有良好的流体力学性能。  相似文献   

7.
对超临界流体萃取固态物料进行了萃取机理分析,建立了超临界流体萃取固态物料的萃取模型,给出了宏观萃取速率表达式,提出了验证实验方案.  相似文献   

8.
超临界流体技术的应用研究进展   总被引:5,自引:1,他引:5  
主要对超临界流体技术中的超临界二氧化碳萃取、超临界丙烷萃取、超临界水氧化法三种技术,在研究和工业化生产中的应用情况作了详细的叙述,并对超临界流体技术的发展进行了展望.  相似文献   

9.
超临界CO2流体萃取技术在天然物提取上的研究进展   总被引:27,自引:0,他引:27  
天然物的超临界CO2流体萃取是超临界流体技术了活跃的领域,在过去的几十年里,在天然物特别是植物精油的超临界CO2流体萃取的实验方法,数学模型和过程怕研究取得了不少研究成果,而有关这方面的综述和未见报道,本文拟就近年来天然物的超临界CO2流体萃取的这些方面的最新研究进展作一综述,主要介绍该技术的实验方法,相关的分析手段,溶解度和相平衡关联方程,数学模型和过程模拟的最新研究成果。  相似文献   

10.
《杭州科技》2004,(6):65-65
超临界流体萃取技术是近三十多年来发展起来的新技术。所谓超临界流体,是指温度及压力处于临界温度及临界压力以上的流体,它兼有液体和气体的优点。超临界流体的粘度小、扩散系数大、密度大,具有良好的溶解性和传质特性,在临界点附近流体的这种特性对压力和温度的变化非常敏感。超临界流体既是一种良好的分离介质,又是一种良好的反应介质,因此该技术不论在基础理论或应用领域都取得了长足进展。作为一种共性技术,与新的分离、反应过程的开发密切相关,该技术的应用正渗透到制药、材料制备、生物技术、环境污染控制等高新技术领域,在各个行业…  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号