恒压操作下深层过滤系数λ的研究

分析了影响深层过滤系数λ的几种因素,着重介绍了过滤介质表面积、流路几何形状、介质层孔隙内液体流动速度影响过滤系数的三种模型。建立了恒压操作下,过滤系数λ与比堆积量σ间的函数关系式,并通过实验确定式中的待定指数。是研究恒压操作下深层过滤理论的基础。     

恒压操作下深层过滤系数λ的研究

分析了影响深层过滤系数λ的几种因素 ,着重介绍了过滤介质表面积、流路几何形状、介质层孔隙内液体流动速度影响过滤系数的三种模型。建立了恒压操作下 ,过滤系数λ与比堆积量σ间的函数关系式 ,并通过实验确定式中的待定指数。是研究恒压操作下深层过滤理论的基础。     

生产无机盐的主要过程及设备——过滤(概述)

<正>过滤是一种分离悬浮在液体或气体中的固体颗粒的操作,现仅讨论悬浮液的过滤。悬浮液称为滤浆,滤浆中的固体颗粒称为滤渣,积聚在过滤介质上的滤渣称为滤饼,透过滤饼和过滤介质的澄清液体称为滤液。评价过滤操作优异的标志之一是过滤速度,影响过滤速度的因素主要有压力差、过滤面积、滤饼的阻力、滤液的黏度、过滤介质和最初滤饼层的     

板框压滤机的选择和操作参数的确定

研究了板框压滤机先恒速后恒压过滤操作规律,提出了过滤面积和滤框厚度的选择以及操作压力和操作周期的确定方法,附有计算实例。     

滤布阻力对恒压过滤最佳操作周期的影响

导出考虑滤布阻力时恒压过滤最佳操作周期的严格公式,并给出了忽略滤布阻力对最佳周期影响的严格判据(M-判据),对该判据的研究表明,当过滤辅助时间较短时,简单地根据滤布阻力当量滤液量和实际滤液量之比(Ve/V)来判断能否忽略滤布阻力对最佳操作周期的影响是不够充分的。     

助滤剂增强恒压过滤机生产能力的计算方法

论述了恒压操作预涂助滤剂后,由于介质阻力发生变化对过滤机生产能力的影响,并提出了预涂助滤剂后,过滤介质常数的计算式。     

熔融结晶洗涤塔内过滤过程的研究

针对熔融结晶洗涤塔的过滤操作模式,根据表面过滤原理分析了洗涤塔内过滤段的物理模型和数学模型,建立了过滤微分方程和相关边界条件;通过过滤方程的求解,建立了过滤段滤饼过滤的压力分布公式以及滤液体积流率与滤饼变化厚度的关系式,并对相关主要影响因素进行了分析。结果表明,洗涤塔过滤段滤液体积流率与压力降、比滤阻、过滤介质阻力、滤...     

几种常见液固过滤方法的能耗与物耗及改进方向

液固过滤过程中能耗与物耗相当可观,对我国节能减排任务的负面影响不可忽视.分析了四种常见的过滤方法(循环过滤、多级过滤、真空过滤和错流过滤)的高能耗与三种常见的过滤装置与方法(手动板框压滤机,分散的深层过滤器与助滤过滤)的高物耗的概况,并简单叙述了改造的大致方向.     

低浊度废水的微絮凝变孔隙深层过滤

研究了微絮凝变孔隙深层过滤处理低浊度废水时,滤料粒径、絮凝剂种类、投加量、滤速等因素对过滤效果的影响。试验结果表明：由于变孔隙结构等原因,该系统具有用药量省、阻力损失小、出水量大及整床过滤效能好等优点。     

滤床过滤系数的确定方法

过滤系数λ是表征深层过滤性能的重要参数,用试验的方法测定滤床过滤系数较为复杂。通过试验法和数学模拟法对不同粗细的滤料滤床进行研究,确定其λ的具体值,通过比较两者的结果发现,利用数学模拟法替代复杂的试验方法来确定实际滤床的过滤系数和预测运行状况是简便可行的。     

深层过滤流体力学性能的研究

深层过滤是化工过程非均相分离中最基本的方法之一,在石油化工水处理方面占有很重要的地位。重点对炉渣滤料深层过滤的流体力学性能进行了研究,并根据炉渣滤料的过滤试验数据,进行了数学模型的数值计算。结果表明,文中所采用的数学模型可以用来描述深层过滤过程流体力学性能,使Kozeng方程可以直接用于计算深层过滤过程中床层压降随时间的增长规律。     

恒压过滤介质阻力分析

A mathematical model for constant pressure filtration is established. The distribution of hydraulic pressure within the cake and the medium resistance are measured. The medium resistance Rm is calculated from the suppositional filtration time Ore. It is demonstrated that Rm is nearly a constant for a given filter cloth.     

计算机模拟醋酸纤维纺丝液的过滤过程

通过恒压过滤理论与高分子浓溶液的粘度特性对醋酸纤维纺丝液的过滤过程做了理论推导,通过计算机对纺丝液固含量、过滤温度、过滤压力等工艺参数对纺丝液过滤过程的影响做了模拟和分析。结果表明：纺鳇液圃含量升高后体系粘度会增加,同时过滤速率明显降低;升高过滤温度后纺丝液粘度有所下降,过滤速率将增大;纺丝液的过滤常数会随压差的升高而增大,过滤速率也随之所提高。     

Analysis of Gravity Filtration Behaviors of Waterworks Sludge Based upon Sedimentation Tests

Both gravity filtration experiments under constant pressure conditions and gravity sedimentation experiments were conducted using the municipal waterworks sludge. It was clarified from the theoretical analysis that the effect of sedimentation on the filtration rate was noticeable for the sludge used in this study. The local specific flow resistance at various sludge concentrations was determined by the sedimentation velocity method. The local porosity was related to the local solid compressive pressure by the sedimentation equilibrium method. The decline behaviors in the filtration rate in gravity filtration accompanied by sedimentation were well evaluated only from the sedimentation data based upon the sedimentation velocity method and the sedimentation equilibrium method.     

Cake properties of nanocolloid evaluated by variable pressure filtration associated with reduction in cake surface area

A potential method has been developed for evaluating simultaneously both the average specific resistance and average porosity of the filter cake formed in unstirred dead‐end ultrafiltration of nanocolloids such as bovine serum albumin solution and silica sol. The method consists of variable pressure filtration followed by constant pressure filtration. The relation between the average specific cake resistance and the pressure drop across the cake was determined from the evolution of the filtration rate with time in the course of the variable pressure filtration period, based on the compressible cake filtration model. The average porosity was evaluated from the significant flux decline caused by a sudden reduction in the cake surface area in the middle of the constant pressure filtration period. The pressure dependences of both the average specific cake resistance and average cake porosity were obtained from only two runs which differed from each other in the pressure profiles. © 2014 American Institute of Chemical Engineers AIChE J, 60: 3869–3877, 2014     

筒式活性炭二维深层过滤研究

简单介绍了深层过滤与表层过滤及其研究现状。根据基本假设，借鉴前人研究成果，引入有效面积系数，推导出简式活性炭二维深层过滤理论公式。通过自行研制的简式活性炭二维深层过滤实验装置进行实验。获得实验数据，并进行分析讨论。结果证明了理论与实验结果的一致性。为二维深层过滤研究提供了一个新方法。     

固定床颗粒层过滤性能分析及预测

使用两种滤料颗粒在一套冷态试验装置上考察了过滤气速和颗粒层厚度对颗粒层过滤性能的影响。结合颗粒层过滤宏观模型,分析了不同操作条件下粉尘比沉积率σ对颗粒层粉尘捕集能力偏离初始值程度F和过滤压降偏离初始值程度G的影响,然后预测了过滤效率和压降。结果表明,试验范围内,随着σ的增大,F呈现先增加后降低的变化趋势,而G逐渐增加。结合过滤气速u=0.2~0.6 m·s^-1、颗粒层厚度L=0.11~0.2 m条件下的试验数据拟合得到了F-σ和G-σ函数关系,过滤效率和压降的计算值与试验吻合较好,优于文献中相关公式,可为颗粒床过滤性能的预测提供参考。     

Factors affecting cake resistance in non-Newtonian filtration

A methodology for evaluation of surface effects including polymer adsorption-gel formation or slip within the pores of a filter cake has been developed and applied to constant pressure filtration of calcium carbonate in aqueous hydroxyethyl cellulose (Natrosol 250G, Hercules Powder Company) slurries. The fundamental framework of non-Newtonian filtration is generalized to include the Blake, Kozeny-Ergun and Kozeny-Carman cake models and the cake resistances γ_K and α_R, in conjunction with the correction terms J_RN and J_gen, within a unified framework. Relationships are developed between the latter quantities and the effect of the bed model on the evaluations of the filtration characteristics is delineated. Significant polymer adsorption-gel formation was found to take place in the constant pressure filtration of calcium carbonate in aqueous Natrosol 250G slurries. The resultant cake porosities were larger and the effective cake porosities lower than comparable porosities for cakes deposited from water slurries. The wide variation of J_RN with the characteristic index N is attributed to the small size of the slurry particles. Polymer adsorption is shown to extend, and slip on the particle surface to reduce the variation of J_RN with N.