PARAMETER ESTIMATION IN CAKE WASHING

The uniform-film model for cake washing considers the cake to be composed of channels in which a stagnant film of solute-rich filtrate adheres to the surface of the channel.

Two independent methods are presented for an unbiased evaluation of the uniform-film model parameters. The first is an iterative procedure which requires adjustment of only one model parameter, and the second is a direct analytical procedure based on the method of moments. Both require experimental data to identify the model parameters.

Application of the two methods give wet-base porosities greater than unity which suggests that the experimental data used to determine the model parameters is beyond the domain of applicability of the uniform-film model.     

洗衣机过滤器外壳注塑模设计

通过对洗衣机过滤器外壳结构特点与模具设计方案的分析,介绍了洗衣机过滤器外壳注塑模的结构与工作过程,重点阐述了分型抽芯机构和机动旋转脱螺纹传动机构有关的理论与计算方法。生产实践证明,该模具设计合理,动作准确可靠,塑料件质量良好,生产效率高,完全能够满足用户的要求。     

OPTIMIZATION OF THE LOCATIONS OF SIDE STREAMS IN A FILTER CAKE WASHING PROCESS

A macroscopic model was developed to perform optimization studies for countercurrent, non-equilibrium, displacement filter cake washing on a belt filter with incoming side streams. Each washing stage was assumed to contain a number of perfect mixing cells connected in series. The optimum locations of the side streams, which yielded the minimum exit solute concentration for the washed cake, were evaluated. Three cases were considered: Incoming side stream added to the wash liquor flow, incoming side stream added to the cake flow and incoming side streams added to both flows simultaneously. A parameter study was performed systematically to determine the effect of washing parameters on the optimum side stream locations.     

NAFC气浮处理洗煤废水的试验

采用机械散气溶气气浮柱（NAFC）气浮处理洗煤废水.结果表明：PAM用量为4mg/L、PAC用量为60mg/L、煤油用量为15mg/L、两进水口间距为160cm和回流比为40%的条件下,废水浊度从274NTU下降到8NTU,COD从210.6mg/L下降到35.2mg/L,出水水质达到回用水要求,可以用于冲厕和绿化用水等.     

A MODEL FOR FREENESS MEASUREMENT OF PAPERMAKING SUSPENSIONS

In the pulp and paper industry, it is often necessary to characterize the drainage capability or a pulp on the paper machines. The industry uses a standard measure called the freeness to represent this and other properties for papermaking pulps.

The freeness is the total volume of water discharged from a side orifice of a specific configuration while the pulp suspension drains freely under gravity. In this paper, a model for the gravity filtration of pulp suspensions forming a compressible pulp mat is along with some empirical treatment of the flow is used to model the freeness test. The gravity drainage process is assumed to be described by a cake filtration process with the pressure at each instant being given by the gravity head.

From the model, the critical parameters governing the freeness of a pulp suspension are shown to be the specific surface area and the specific volume of the pulp fibers in addition to the compressibility of the pulp mat. When these parameters are available from independent gravity drainage measurements, the freeness itself can be estimated. Estimated freeness values are in agreement with experimental measurements for pulps which are reasonably free of fines. When fines are present however, they get entrapped within the pulp mats decreasing their permeability. The model predictions are higher than experimental measurements in this case.     

丽赛织物洗涤性能研究

测试了纯棉织物以及棉／丽赛、棉／涤纶和棉／粘交织物洗涤一定次数后拉伸性能和悬垂性能的变化,试验结果表明,经过10次洗涤后棉／丽赛交织物的耐洗涤性能较纯棉织物好,比棉／粘交织物有明显提高。     

VAPOR-LIQUID EQUILIBRIA PREDICTION FOR SYSTEMS CONTAINING UNSATURATED HYDROCARBONS THE UNIFAC MODEL FOR PREDICTING BOILING TEMPERATURE

The original UNIFAC method is used to predict isobaric boiling temperatures for one ternary and twelve binary systems containing isomeric n-alkenes and. n-alkynes as one component. Boiling temperatures are calculated using group interaction parameters available in the literature and determined by the authors. In most cases an agreement between the experimental and predicted values is acceptable for engineering purposes     

ANALYSIS OF THE ELECTROFILTRATION MECHANISM BASED ON MULTIPHASE FILTRATION THEORY

A mathematical model based on multiphase filtration theory is developed to describe the electrofiltration process. The model takes both electrophoretic and electroosmotic effects into account. The electrophoretic migration velocity of solid particles is predicted from the model using the filtrate volume time data obtained from electrofiltration experiments.     

用于渗透汽化过程的中空纤维膜器工艺流程设计模型

本文通过渗透汽化过程中物料，热量衡算，进行合理假设，建立工艺流程设计的数学模型，为中空纤维膜器在渗透气化过程应用提供设计依据，并以生产无水乙醇为例求解出数学模型。     

ESTIMATION OF THE COEFFICIENTS OF A MULTIVARIATE LINEAR FILTER USING THE INNOVATIONS ALGORITHM

It is shown under mild conditions that the estimators of the coefficient matrices obtained by applying the innovations algorithm to the sample covariances of observations of the multivariate linear time series X _t = ∑^∞ _{j =0}ψ _i Z _t , t = 0, ±1, ±2, . . ., are consistent. The asymptotic distribution of the estimators is found to have a very simple form which generalizes the corresponding univariate result of Brockwell and Davis (Simple consistent estimation of the coefficients of a linear filter. In Stochastic Processes and Their Applications . Amsterdam: North- Holland, pp. 47--59). The asymptotic distribution of the corresponding estimator of the spectral density matrix is also derived. Some simulation results are presented to illustrate the small-sample behaviour of the estimators.     

SIMPLIFIED MODELLING FOR THE DRYING OF A NON HYGROSCOPIC CAPILLARY POROUS BODY USING A COMBINATION OF DIELECTRIC AND CONVECTIVE HEATING

The drying of non-hygroscopic, capillary porous materials with dielectric and convective heating is considered. Simplified models are used to examine the effect of a partially wetted surface or receding evaporation front on the temperature of the wet material. Physical mechanisms which can enhance the internal moisture flow, as compared with convective heating alone, are examined ualitatively.     

DERIVATION OF CONSTITUTIVE EQUATIONS FOR INTERFACIAL FORCE AND REYNOLDS STRESS FOR A SUSPENSION OF SPHERES USING ENSEMBLE CELL AVERAGING

A novel new ensemble cell averaging technique has been used to derive various interfacial forces and Reynolds stresses for inviscid two-fluid models of two-phase. New terms, not seen in the spatially averaged conservation equations, have been found. Moreover, deficiencies inherent in spatial averaging techniques have been demonstrated.     

新型生物滴滤池处理生活污水的中试研究

试验研究采用滴滤模式与淹没模式相结合的新型滴滤池处理生活污水。考察了该装置对生活污水中COD、NH3-N、TN、TP污染物的去除效果。试验结果表明,该滤池对COD、NH3-N和TP有较好的去除效果,去除率分别达到79.2%、90.8%和70.05%,但对TN的去除率不超过20%。通过与传统活性污泥法、高负荷生物滴滤池等进行电能能耗对比,新型生物滤池电能消耗不超过22%。     

SIMPLIFIED MODELLING FOR THE DRYING OF A NON HYGROSCOPIC CAPILLARY POROUS BODY USING A COMBINATION OF DIELECTRIC AND CONVECTIVE HEATING

The drying of non-hygroscopic, capillary porous materials with dielectric and convective heating is considered. Simplified models are used to examine the effect of a partially wetted surface or receding evaporation front on the temperature of the wet material. Physical mechanisms which can enhance the internal moisture flow, as compared with convective heating alone, are examined ualitatively.     

用微扰理论建立水的分子热力学模型

提出1种水的分子热力学模型,从微扰理论出发,建立了自由能及其它热力学函数的关系式.水分子间作用包括硬球、色散、静电及诱导几个部分.通过同时关联0～300°C下饱和水蒸气压及液体密度数据获得分子参数,还预测了水的蒸发焓及饱和水蒸气的比容,比较了文献中处理水的几种理论方法.结果表明,本模型简单,且较接近实际.     

基于双流体模型的流化床模拟

从单相流体力学中描述气体流动的Navier-Stokes方程和单颗粒运动的Newton方程出发,使用比较严格的体积平均法推导出描述气固两相宏观流动的模型方程组并设法确定了模型参数,把该方程组加以简化,能得到Gidaspow、Blake和Davidson等人的模型方程,初步证明了模型的正确性,求解使用了经本文改进的基于控制容积有限差分的IPSA方法,编制了通用程序,模拟了二维射流流化床中浓密气固两相的流动,并计算出射流的穿透深度。     

国产化大氮肥二期液氮洗装置运行总结

总结国产化大氮肥二期液氮洗装置试车及开车以来的运行情况,针对设计及开车过程中出现的问题,提出解决办法和防范措施,消除了缺陷和隐患,保证了装置安全稳定运行。     

洗毛废水深度治理研究

提出了用烟尘和铝渣作为处理剂对洗毛废水进行深度治理的新方法，给出了最佳处理条件，并对处理机进行了分析。吸附作用和腐蚀电池还原脱色作用是该法处理速度快，效率高的主要原因。     

洗衣机内桶专用树脂结构与性能分析

对 5种国内外洗衣机内桶专用树脂进行了序列结构分析 (用核磁共振波谱NMR)、热性能测定 (用差示扫描量热法DSC)、相对分子质量及其分布测定 (用凝胶渗透色谱法GPC)和力学性能测定。比较了它们的差别并讨论了造成这些差别的因素     

A NEW MODEL FOR CAPILLARY FILTRATION BASED ON RECENT ELECTRON MICROSCOPIC STUDIES OF ENDOTHELIAL JUNCTIONS

Existing models to predict the filtration and permeability of hydrophilic solutes in the capillary interendothelial cleft have been based largely on one-dimensional models of channels with constrictions that are represented by long rectangular slits of 6 to 8 nm gap width that run along the length of the junction and do not interact with one another [1,7-10]. It has been commonly assumed based on these simple models that the water and solute fluxes are proportional to the area of the junction that is open. Recent electron microscopic studies [7, 11] using freeze fracture and ultrathin serial sectioning techniques indicate that the pores in the tight junctions might be numerous much narrower disruptions in the protein strands of 10 to 20 nm length. A new model is proposed in which the pores are short periodically distributed equivalent cylindrical holes in the junctional strands that have dimensions comparable to individual missing proteins. Since these pores have spacings which are small compared to the depth of the cleft the interaction between pores, neglected in previous models, becomes a crucial determinant of the transport behavior. A two-dimensional Hele-Shaw theory for filtration is developed to describe this interaction. This new model shows that the flux is not proportional to the length of open junction, and far fewer pores are required to accommodate the experimentally measured filtration fluxes than heretofore realized; e.g. the model predicts that only one junctional protein in eight needs to be absent to account for the measured hydraulic conductivity of frog mesentery capillaries and one in eighty for frog muscle. In contrast, traditional one-dimensional models with slit constrictions predict that the junction is open along nearly its entire length for frog mesentery capillaries and ten percent open for muscle capillaries. This basic Hele-Shaw model is then modified to describe the resistance of bridging molecules or fibers that might span the wide portions of the cleft as proposed in the fiber matrix model of Curry and Michel [16]. The results of this model depart significantly from those of the fiber matrix theory developed in [16] using the Carman-Kozeny equation and suggest that the fiber matrix, if it exists in the wide portion of the cleft, must be much more diffuse than previously predicted. The periodic fiber model shows that the Carman-Kozeny equation grossly underpredicts the filtration resistance since it neglects the influence of the channel walls on the viscous layers surrounding the fibers.