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1.
用自行研制的计算机控制的在线管式膜器环隙压力测试系统实测分析了不同入口压力、不同悬浮液浓度和不同膜器环隙大小下的旋转横流膜微滤渗透通量大小及环隙压力分布规律,与一般横流膜微滤的环隙压力分布及渗透通量大小进行了对比,为进一步研究膜微滤强化机理、探讨减少或解决浓差极化和膜污染的方法提供了实测依据.  相似文献   

2.
研究了湍流促进器对19通道陶瓷膜微滤CaSO4悬浆液过程的影响,优化湍流促进器的优化设计参数。确定螺旋式湍流促进器的强化效果较好。设置方式为内圈螺间距4 mm,外径3.4 mm和外圈螺间距8 mm,外径3.4 mm的组合式,螺旋湍流促进器的强化效果最佳,膜通量提高23.76%,并有效地改善了膜通道内流体流动状态。  相似文献   

3.
陶瓷微滤膜处理钛白粉水洗液的过程强化研究   总被引:11,自引:1,他引:10  
本文采用湍流促进器和反冲对陶瓷膜处理钛白粉水洗液的微滤过程进行了强化研究。实验和以上两种方法均不同程度地提高了渗透通量,降低了能耗。考察卫湍流促进器结构参数和反冲持续时间、压力、周期对强化效果的影响,确定了合适的湍流促进器结构参数和反冲条件,并对反冲的重复性进行了实验考察。  相似文献   

4.
膜微滤强化技术国内研究进展   总被引:2,自引:0,他引:2  
概述了国内膜微滤强化技术研究进展,分析了附加场、设置湍流促进器或脉动进料方法,以及旋转横流强化、旋转动态膜强化、组合强化等方法的特点。  相似文献   

5.
在固定反冲条件下,研究了螺旋型湍流促进器及其螺杆直径、螺间距等参数对19通道无机陶瓷膜分离轻质碳酸钙悬浆液的强化过程,确定了湍流促进器的优化设计参数,并在优化条件下,对操作压力、操作温度、膜面流量和溶液浓度等操作条件进行了研究。  相似文献   

6.
为提高平板膜过滤器的过滤性能,设计了一种新型的锯齿形湍流促进膜过滤器。以含有不同浓度的Si C颗粒废水为研究对象,通过错流微滤实验对促进器强化过滤性能进行了研究,分析了促进器作用下膜组件的流动阻力和能量利用率。结果表明,锯齿形促进器可使常规过滤渗透通量提高3.46倍,尤其是在低进料流量、低雷诺数下能有效地强化膜通道内的湍动能,提高能量利用率。锯齿形促进器的强化作用与锯齿的疏密有关,当锯齿的疏密程度增加50%时,单齿强化过滤效率可提高3.7倍。  相似文献   

7.
设计制作了滤毒器通风管路中风量与阻力测定的实验装置。在滤毒器额定风量下,分别用热球风速仪法和动压法测定了不同测点的风量,研究了通风管路中风量的横向分布,井在不同风量条件下对滤毒器的阻力进行测定,确定了在风量的允许偏差范围内阻力的允许偏差。结果表明:热球风速仪法比动压法的测定结果更为准确;通风管路中风量的横向分布呈现无规律状态;在滤毒器风量的允许偏差范围±10%内,滤毒器的允许阻力偏差为±53.57Pa。  相似文献   

8.
采用混凝气浮+砂滤+超滤处理某制盐厂卤水,研究了不同运行条件下,膜系统的运行稳定性,分别进行了卤水直接超滤30L/㎡·h、25L/㎡·h和20L/㎡·h以及砂滤和和混凝气浮+砂滤预处理后超滤20L/㎡·h下的试验,对比了各个运行条件下,膜系统运行的稳定性;分析了砂滤、混凝气浮+砂滤和混凝气浮+砂滤+超滤等不同处理工艺下的卤水处理效果及膜CEB清洗效果。试验结果表明:砂滤预处理后,膜系统的运行稳定性略有提高,混凝气浮+砂滤预处理后,膜系统运行稳定性有很大的提高,20L/㎡·h下连续运行一周TMP未见明显增长;混凝气浮+砂滤对卤水TOC、浊度SS等都有较好的去除效果,其去除率依次为35.6%~38.9%、38.8%~54.7%和68.7%~73.4%,混凝气浮+砂滤+超滤对TOC和浊度去除率提高为38.6%~44.2%和96.3%~97.6%;0.1%的Na Cl O的CEB清洗效果良好纯水20L/㎡·h下TMP恢复率高达80.6%,说明造成膜污染的物质主要为有机物。  相似文献   

9.
崔晓钰  石景祯  徐之平  唐聪 《化工学报》2007,58(11):2816-2821
膜反转板式降膜再生器是一种结合板式降膜与膜反转技术的新再生器型式。掌握其性能对今后的工业应用十分重要。本文以一个膜反转板式降膜再生器与板式降膜再生器作为比较。在相同设计条件下设计获得两个不同型式的再生器,通过对数学模型的求解,进行了不同发生压力、溶液流量、进口浓度、进口温度及加热条件下两者传热传质性能的计算与比较。结果表明在不同工况条件下,两者性能变化有所不同。由此,在膜反转板式降膜再生器替代板式降膜再生器的应用中应当考虑它们变工况性能的差异。  相似文献   

10.
以改善液固一体式膜反应器中膜过滤性能为目的,设计了3种外置式湍流促进器进行膜过滤强化实验,考察了湍流促进器的构型、旋转速度等因素对膜通量的影响。结果表明,旋转的湍流促进器可以明显地提高膜通量,其中推进式湍流促进器的强化效果最明显;随着湍流促进器旋转速度的增加,膜通量也相应增加;采用该湍流促进器可以进行高悬浮液质量浓度的膜过滤强化实验。  相似文献   

11.
《分离科学与技术》2012,47(2):286-309
Abstract

The static turbulence promoters presented in this work are designed to enhance filtration within tubular ceramic membranes of 0.5 micron pore size. Permeate flux enhancement still remains a topical problem during tangential crossflow filtration. The decline in flux with time is due to the usual phenomena of concentration polarization and membrane fouling, operating parameters including the system pressures, feed composition, membrane type and configuration, and the hydrodynamics within the membrane module. Solute accumulates on the membrane surface and forms a high concentration gel layer, thus increasing the effective membrane thickness and reduces its hydraulic permeability. Turbulence promoters of varying pitch lengths have been incorporated into the work to ultimately reduce the deposition of bentonite particles on the membrane surface during microfiltration. Yeast suspensions have previously been used as feed suspensions in order to compare the effectiveness of the turbulence promoters with an organic foulant. The objective of this work was to investigate the influence of static promoter geometry on flux sustainability enhancement during bentonite suspension filtration. All experiments have been conducted on a tubular ceramic membrane and the experimental membrane rig as shown in this paper. The effects of feed concentration, feed temperature, system pressures, and crossflow rates on the membrane flux sustainability were investigated. It was found that the promoters greatly improved flux sustainability and membrane efficiency over time and in some cases, a loss of 3% in membrane efficiency was realized with turbulence promoters at higher feed temperatures. The use of the turbulence promoter caused a large scouring of the membrane surface and membrane cleaning was significantly improved compared to the experiments without the promoters.  相似文献   

12.
《分离科学与技术》2012,47(9):1945-1963
Abstract

The use of turbulence promoters in membrane based processes have been investigated and are increasingly been used in industrial applications to minimize fouling and enhance the membrane flux. The efficiency of crossflow microfiltration is limited by membrane fouling and concentration polarization leading to flux decline during operation. A detailed study was carried out in the microfiltration of yeast suspensions using an in‐house rig and three different static turbulence promoters of varying pitch lengths. The design of the promoters incorporates a helical thread around the length of the insert, which induces turbulent flow through the membrane. This promotes good mixing of the feed fluid and minimizes concentration polarization effects. The testing of tubular membranes with the static inserts has been carried out and the results are included in the report. The pitch lengths used were 7 mm, 10 mm, and 14 mm and the parameters investigated included temperature, CFV, concentration of feed suspension and pressure. The flux decline data was recorded over a 50 minute filtration cycle and the cleaning protocol was employed after every cycle to restore the permeability of the membrane. A comparison of the membrane performance and efficiency of the three swirls inserts of varying pitch lengths together with a comparison of the degree of total, reversible, and irreversible fouling data amongst others are reported and discussed. The results obtained during the investigations of flux enhancement via static turbulence promoters into the tubular membranes are presented and are selected to differentiate the efficiency of the inserts and the degree of fouling associated with them.  相似文献   

13.
The performance characteristics of an oscillatory membrane photocatalytic reactor were investigated using dye degradation over a suspended ZnO catalyst as a model reaction. Both flat‐surface membranes and ones with transverse turbulence promoters (TP) were used. Application of oscillatory motion can be effective in enhancing the performance of suspended‐catalyst membrane photocatalytic reactors. The eddy formation and vortex shedding when using membranes with TP gave rise to several synergistic effects by providing effective removal of catalyst deposits from the membrane surface, which enhanced the flux and increased the suspended‐catalyst fraction in solution, which consequently enhanced the reaction rate. The effective mixing in the reaction channel minimized particles sedimentation and agglomeration which further enhanced the catalyst suspension and increased its effective reaction area. The specific energy consumption favorably compared to a membrane cross‐flow filtration system.  相似文献   

14.
周民杰  崔鹏 《化学工程》2007,35(3):34-37
采用湍流促进器对陶瓷膜分离TiO2超细粒子悬浆液微滤过程进行了强化研究。考察了湍流促进器结构参数对强化过程的影响,确定了合适的湍流促进器为螺旋式湍流促进器,其结构参数为螺杆直径2 mm,螺距20 mm;探讨了湍流促进器的强化机理,同时对湍流促进器的有效性进行了实验考察。研究表明,采用这种方法提高了渗透通量。  相似文献   

15.
Mass transfer was studied at a rotating cylinder electrode with different turbulence promoters using the reduction of ferricyanide as a test reaction. Four types of turbulence promoters were examined: expanded plastic meshes, Teflon structures, a plastic woven mesh and a plastic perforated net, which were rotated together with the electrode. The best performance was obtained for the Teflon structures at low rotation speeds and for the plastic woven mesh at high rotation speeds. The effect of both the length and the number of sheets of the turbulence promoters as well as the use of static promoters were also analysed. Comparisons of mass-transfer performance of turbulence promoters are made with other three-dimensional structures. The mass-transfer enhancement factor related to a smooth rotating cylinder electrode is twice as large.  相似文献   

16.
采用曝气强化管式膜超滤高岭土混合液,考察了低膜面流速下曝气对强化膜分离过程影响,探讨了曝气对膜面水力特征及膜污染过程影响,并对过滤介质影响及膜污染阻力构成进行了研究。结果表明,在低膜面流速下,通过向管式膜引入曝气使膜表面形成气液两相流,可实现膜通量稳定保持在15L/(m2·h)以上。不仅如此,曝气的引入使膜表面雷诺数由1800~2500增至3300~4500,显著增强了膜表面湍流程度,并且实现了低膜面流速下使膜污染指数控制在较低水平,节省了运行能耗。此外,曝气的引入主要减轻了膜表面滤饼污染,使膜过滤总阻力减小且对高岭土截留效率影响不大,但强烈的膜面传质使高岭土粒径有减小趋势,并且膜表面形成污染阻力以不可逆污染层为主,不利于膜污染长周期控制。  相似文献   

17.
The aim of this work was to investigate possible improvement of non-sucrose compounds separation from the syrup of raw brown sugar by application of a static mixer in an ultrafiltration process. The static mixer was expected to reduce the concentration polarization and fouling of the membrane. Non-affinated B sugar from the second stage of crystallization, diluted to 60°Bx dry matter, was used for preparing the solution subjected to the ultrafiltration. The cross-flow filtration, at a laboratory level, was carried out on the tubular ceramic membrane (Schumasiv Pall, USA), with a pore diameter of 5 nm. The separation was performed under various working conditions, with and without the presence of static mixer. The effect of turbulence promotion on filtration performances was investigated by using Kenics static mixer (FMX8124-AC, Omega). The process efficiency was quantified through the achieved values of the permeate flux, its colour and dry matter content, while the working factors were: fluid flow-rate, temperature, transmembrane pressure (TMP) and process duration. The positive effects of mixer application were proved.  相似文献   

18.
Cross-flow filtration is a filtration process for separation of a disperse phase from liquids. Suspension flows tangentially to a membrane and the filtrate is drawn off perpendicular to the direction of flow. Formation of a filter cake on the membrane is thus prevented, reduced, or its composition, modified. The principle of the separation is based on tow opposing effects: on the one hand, the particles are transported by the filtration flux to the membrane where they cause and increase in concentration; on the other hand, concentration differences are again reduced by the turbulence of the cross-flow and by Brownian motion of the particles. The two mechanisms compete with each other and depend upon particle size in different ways. An energetic comparison of the two effects yields the separation law of cross-flow filtration as a steady state solution of the Fokker-Planck equation. The separation law has an exponential form and assigns each particle size a separation probability with which it reaches the membrane. Once on the membrane the particles may form a filter cake, flow through the pores or return to the bulk flow. If the particles remain on the membrane the ranges of layer-free and cake-forming filtration can be calculated from the hydro-dynamic and geometric conditions of the cross-flow filter. Conventional cake filtration is regarded as limiting case. In continuous cross-flow filtration process a low separation probability through the filtration pressure on selection of the filter medium resistance.  相似文献   

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