催化裂化沉降器新型高效旋流快分器内气固两相流动

用CFX软件对催化裂化沉降器新型旋流快分器的气相流场进行了三维模拟,湍流模型采用雷诺应力输运方程模型.计算结果与用五孔探针测试的气相流场实验结果吻合很好.采用离散轨道模型对该旋流快分器内颗粒的运动情况进行了计算,并由此估算了旋流快分器的分级效率和总分离效率.模拟结果表明：该新型旋流头可消除现有旋流头喷出口附近的短路流,更有利于提高旋流快分器的效率.两种结构形式的旋流快分器分离效率的计算对比说明：在旋流头处加入一个内构件,是很有价值的改进.     

催化裂化沉降器旋流快分系统内两种旋流头的性能对比

通过冷态对比实验,研究了旋流快分系统（VQS）内两种新型旋流头的分离性能,结果表明B型旋流头采用大弧切向出口后,对含尘气流具有加速旋转的作用,可使颗粒喷出后获得更高的切向速度,从而提高系统的分离效率。采用Fluent软件对VQS内气固两相流进行了数值模拟,重点考察了A、B型旋流头的流场分布和分离特性。模拟结果表明：含尘气流由B型旋流头喷出后,切向速度较大,离心力较强,增加了颗粒在稳定分离区内分离的概率;同时,含尘气流喷出后气量大部分集中在封闭罩内壁附近下行流动,下行轴向速度较大,有利于颗粒下行分离。此外,相比于A型旋流头,B型旋流头的分离优势在于可大大提高对中粗颗粒的捕集能力。因此工业应用中推荐采用B型旋流头,以更好地满足工业生产的需求。     

斜板沉降分离器分离模型

在斜板沉降分离器的液滴动力模型基础上,建立了关于斜板分离器的分离过程数学模型,并分析了分离直径的范围,从而为斜板分离器的设计提供了理论依据。该模型不仅考虑了液滴的上升时间、液滴的聚结时间,还考虑了液膜的稳定时间,这对提高斜板分离器的分离效率具有重要的指导作用。     

旋流塔板的板效率模型

引　言板式塔的操作通常可分为气体为分散相的鼓泡、泡沫工况和液体为分散相的喷射工况 .喷射态操作的塔板 ,虽然其效率一般较低 ,但具有通量大、压降低等重要优点 ,符合现代大工业发展趋势的要求 ,正受到越来越多的重视[1～ 3] .有关鼓泡、泡沫工况下的流体力学和传质过程的研     

新型旋流沉砂池除砂和有机物分离效率的研究

通过污水厂进行的水力模拟试验,研究了4个因素:进水水力条件、螺旋桨叶片数量、螺旋桨转速和螺旋桨片距沉砂池底部的距离,对旋流沉砂池砂粒去除率和有机物分离率的影响。并通过单因素试验和正交试验,得出新型旋流沉砂池对砂粒去除的各因素的最佳的水平条件分别为:螺旋桨叶片数量为6片,水力停留时间为50s,螺旋桨转速为26r/min,螺旋桨叶片距沉砂池底部距离为40mm;对有机物分离的各因素的最佳水平条件分别为:螺旋桨叶片数量为4片,水力停留时间为50s,螺旋桨转速为26r/min,螺旋桨叶片距沉砂池底部距离为50mm。     

结构参数对旋流沉降组合油水分离器性能的影响

对影响旋流沉降组合式油水分离装置分离性能的不同操作参数进行了试验研究。在大量试验数据的基础上,分析了旋流器不同叶片数、出口角,沉降器板长、倾角、板间距及聚结材料对分离性能的影响,试验确定了各个结构参数的适宜值。     

快速絮凝造粒沉降器

详细介绍了以液中造粒技术为理论基础而开发的新型固分离装置－快速絮凝造粒沉降器的特点，过程原理，工艺流程及结构，并讨论了操作参数对分离效果的影响规律。     

重污油旋流沉降组合分离的实验研究

目前,国内外大多数企业对重污油的处理采用沉降、聚结等比较单一的方法。针对该问题,本实验采用了旋流与沉降组合的处理工艺,研究了操作参数和结构参数对重污油分离性能的影响,并对其各个参数进行了优化。实验结果表明：旋流沉降组合的分离性能比单独的沉降分离性能高。     

斜板沉降器的分离特性及实验研究

介绍了斜板沉降器的分离特性及结构原理,通过实验研究了斜板沉降器的板间距、板倾角等结构参数对处理负荷的影响,同时提出了结构参数的一般设计原则,为斜板沉降器的工业化设计提供了理论及实验依据     

旋流板分离器分离性能实验研究

在实验室冷模实验装置上考察了空速和液气比对旋流板分离器总压降和分离效率的影响,为旋流板分离器的工业应用提供了依据。     

一种油田清水剂的合成及应用研究

合成了一种阳离子型清水剂,并对其结构进行了红外谱图、核磁共振谱图表征分析,结果表明该产品与目标产物结构一致。在南海某油田对其净水性能做了现场瓶试试验,在投加量为14 mg/L时,其净水效果良好,下层水中含油质量浓度为79 mg/L。在和多种清水剂的对比试验中发现,该产品的处理效果优于其他几种药剂。     

改良型道尔澄清桶的设计理论基础及应用

阐述了国内盐水澄清桶的设计现状，探讨了设计澄清桶的理论基础，即颗粒沉降速度的求取；介绍了改良型道尔澄清桶的设计特点、若干实用的技术数据及其在青岛海晶化工集团有限公司的使用效果。     

Design and verification of a model secondary clarifier for activated sludge

A model clarifier was designed using conventional methods for the surface calculation and an alternative pathway for the determination of the height and constructed accordingly. In addition, a new approach was used to evaluate the necessary scraper speed in comparison to full-scale clarifiers. Scaling effects were taken into account. The model clarifier was first tested by tracer experiments. Conductivity measurements were used for the clarification zone, whereas the thickening zone was tested using pyrene as an organic tracer compound. Finally, the behaviour of the model clarifier was compared with a full-scale settler. The results indicated that operation of the model clarifier was representative of full-scale behaviour, except for severe overloads. Hence, the small-scale clarifier qualified as a model for small-scale studies and could be installed on large-scale plants to monitor more transparently plant performance and sludge behaviour     

海上油田含聚污水用清水剂性能评价方法

海上聚合物驱采油污水成分复杂、乳化程度高、处理难度大,对清水剂的性能提出了更高要求,传统的清水剂性能评价方法已无法满足要求。分析了传统清水剂性能评价方法中存在的不足,结合海上油田现场采出液处理问题,分别从评价条件、水质性能、絮体性能、溶解及配伍性能方面探讨了海上油田含聚污水用清水剂的评价指标及方法,并提出对清水剂的絮体黏附性和流动性等应给予关注。     

Predicting electrocoat efficiency: a simple data-based model for predicting electrocoat usage

Cationic electrodeposition coatings have had large economic impact, especially in the area of corrosion protection. These primers, along with the use of clad steels, have led auto manufacturers to the extended corrosion warranties now offered. A large part of this and other benefits, such as smoothness, come from the uniform coverage of the cationic electrodeposition process. This highly complex, dynamic process covers the visible and hidden areas of the workpiece with paint of high uniformity. The ability to reach recessed areas has historically been measured by throwpower. This property has great impact not only on the corrosion properties of the coating but also on the economics of coating. We propose a simplified model of the electrodeposition which allows prediction of process parameters and relative usage. The model is founded on observations of currents and voltages measured during the electrodeposition process in the field. This simple model is supplied with data from controlled laboratory experiments: film build versus time over a range of voltages. The model correlates well with observations from the field. Examples of the model include comparisons of PPG 5th and 4th generation electrocoats for both laboratory and field baths. These show the model's utility for predicting usage and for optimizing application properties. A final example involves predicting the feasibility both for process parameters and for the ability to meet coating thickness specifications during the development of a prototype material. Our model provides a systematic way of measuring the implications of improved throwpower. We can assess both the economic (relative usage) and deposition parameters to optimize the overall process.     

关于等幂和的一个猜想

利用差分的技巧给出了陈景润关于等幂和的两个递推公式的简单证明。由此递推公式得到S21(n)|S2m+1(n),S2(n)|S2m(n),同时给出了Bernoulli数B2k+1=0的又一证明。利用一对共轭式,给出陈景润关于等幂和的另一结论的简单证明。通过归纳,给出了等幂和的一个猜想。该猜想和Bernoulli数有着密切的联系。     

Comparison of boundary conditions for predicting the collection efficiency of cyclones

Gas-particle flow in three cyclones was numerically modeled using the Eulerian-Lagrangian approach. A tangential lift-off boundary condition was developed and included in the CFD simulations of cyclone performance via a user-defined function. Particles were considered as detached from the surface if they met the criterion of tangential lift-off; otherwise they were captured by the surface. Prediction of the collection efficiency in cyclones was conducted using the three different boundary conditions: (1) bottom trap only; (2) cone and bottom trap; and (3) the tangential lift-off, which is a combination of trap and reflect. Comparison with experimental data in literature indicates that the tangential lift-off boundary condition yields more accurate predictions than other boundary conditions.     

Numerical model for predicting the efficiency behaviour during pulsed electrochemical machining of steel in NaNO3

A new two-dimensional model is presented that allows describing the high speed electrochemical machining of steel in NaNO₃ solutions. Unlike existing models, local ion concentrations are calculated and used to evaluate local diffusion coefficients and electrolyte conductivity. Secondly, the presence of a super-saturated, honey-like layer on the anode surface is accounted for by introducing a water depletion factor. This factor describes the suppression of the oxygen evolution as the vast increase in ion concentrations reduces the amount of free water molecules at the anode. It is demonstrated that this approach enables to reproduce experimental average efficiency curves over a broad range of electrolyte concentrations with just a limited set of adjustable parameters.     

Determination of Similarity of Explosives for a Model Experiment

By applying the matrix analysis method, the main similarity criteria of an explosive and a material simulating soil properties are deduced. Determination of similar explosives significantly depends on the choice of soil simulator. It is more reasonable to determine first the similar explosive and then the similar material rather than vice versa. Feasibility of the method was verified by comparing the results of model experiments for frozen soils and cement mortar.     

Estimation of the size of a finite population in sequatial sampling:truncatedcombinatiorial numbers

This note considers the problem of unbiased estimation of the size of a finite population, or the number of equiprobable classes in a population, when sequential sampling plans are aplied. Combinatorial numbers, e.g., Stirling numbers of the second kind or Lah numbers, occurring in sampling distributions when the sample size is fixed, have to be adjusted to take into account the stopping rule. This requires the concept of a truncated combinatorial number, and linearly truncated Stirling numbers and Lah numbers are instances discussed here. UMVU estimators of population size are expressible in terms of ratios of such truncated combiantorial numbers.