大型抛射筛数学模型分析

通过抛射筛数学模型建立的因素分析,描述了在这建模过程中众多因素对透筛概率的影响,指出颗粒能否透筛是一个复杂的过程。颗粒透筛的几何概率仅反应颗粒与筛网接触一瞬间的透筛现象,在此之前还有其它因素对颗凿的运动产生影响。大型抛射筛数学模型的建立过程,考虑了颗粒在筛分过程中运动规律及透筛概率规律。     

香蕉型弛张筛3mm干法脱粉在寺河矿选煤厂的应用

为提高物料干法筛分效果,在论述香蕉型弛张筛工作原理和特点的基础上,分析了香蕉型弛张筛3 mm干法脱粉技术在寺河矿选煤厂的应用情况。结果表明:香蕉型弛张筛处理量大,比圆振动弛张筛提高30%以上,可实现物料快速分层,提高透筛率;单台带煤量约320~350 t/h;3 mm筛下限上率3.2%,上层限下率23.1%,下层限下率21.3%;筛分效率达85%,对黏性成团物料具有更好的筛分效果;香蕉型弛张筛安装角度小,占用空间少,改造成本低,降低水耗、电耗、介耗;煤泥量、絮凝剂用量、凝聚剂用量分别减少11.25万、22.50、281.25 t/a,增加经济效益5355.01万元。使用香蕉型弛张筛进行3 mm深度筛分具有可行性。     

基于微孔过滤板的蛋白吸附高通量筛选方法

针对色谱分离过程优化,建立了基于微孔过滤板的蛋白吸附高通量筛选方法,用于介质初筛、吸附性能考察、吸附等温线和吸附动力学测定、吸附和洗脱条件优化等。首先优化了96孔过滤板的操作参数,以2种离子交换介质和2种混合模式介质为典型代表,采用微孔过滤板方法考察了不同介质和液相条件下牛血清白蛋白的吸附,得到结合载量分布图,确定了合适的蛋白吸附和解吸条件。进一步测定了4种介质在特定吸附条件下的吸附等温线和吸附动力学曲线,获得吸附相关参数。最后,采用微孔过滤板进行了洗脱条件优化,并与填充柱色谱分离进行比较,验证了方法的可靠性。结果表明,基于微孔过滤板的蛋白吸附高通量筛选是切实可行的,可以快速筛选色谱介质和液相,优化蛋白分离条件,具有资源消耗小、实验通量大、研发周期短、适用性广、稳定性高的特点,是蛋白色谱分离过程优化的一种新方法。     

利用筛分装置提高磷矿石品位的研究

本文通过试验比较了筛分前后磷矿石的品位及筛下矿石份额,发现筛分装置的筛分间距对筛分结果有很大影响,因此可以通过选择合适的筛分间距来提高磷矿品位,达到化工厂生产对磷矿石品位的要求.     

大型气升环流反应器加置内件时氧传递规律的研究

研究了用结构简单而实用性强的筛板及折皱丝网组件作为内件,来促进大型气升环流反应器中气泡的分散,改善气液两相的混合,从而强化氧传递过程.文中分析了筛板开孔直径与开孔率对氧传递系数的影响,比较了两种内件效果,讨论了最佳结构尺寸.针对高径比大的气升环流系统提出了测定K_La值的平推流动态模型.模型计算结果与实测数据吻合较好.     

拉伸流动静态混合器混合性能的实验研究

设计了1种能够增强聚合物混合效果的拉伸流动静态混合器（EFM）,以高密度聚乙烯/聚苯乙烯（PE⁃HD/PS）作为混合体系,根据共混体系扫描电子显微镜（SEM）照片及分散相的平均粒径,研究了不同盘形结构和不同盘棱间隙（δ）（0.125~2.0 mm）下EFM的混合性能。结果表明,EFM的盘形入口结构对其混合性能影响较小,混合能力随盘棱顶端圆角半径的增大而有所提升,随δ的增大出现先降低再升高又降低的变化趋势。     

冶金焦炭焦末含量及筛分组成试验的影响因素

焦末含量及筛分组成是冶金焦炭的重要指标,讨论了不同采样地点、采样方式及不同筛分方法对该指标的影响。结果表明:避免焦炭在装卸、运输及储存中产生粒度离析,采用机械筛分法或者手筛法是减少对焦末含量及筛分组成影响的有效手段。     

磷复肥喷浆造粒“三内”技术研究与开发(二)

建立三内技术中的内筛分能力计算式 ,探讨了筛面物料运动禾口内筛分结构对筛分的影响 ,为内筛分设计提供了理论依据。     

均衡运动旋转振动筛DEM数值模拟

旋转振动筛广泛应用于各行业对于粉体和胶体的分级。单电机旋振筛的激振力不通过振动体质心,使振动体随质心作圆运动和绕质心作圆锥摆运动。这种运动使得筛面上的垂直振幅不均匀,存在着颗粒物料向筛面周边扩散较快、物料层较厚、筛分效率较低、颗粒均匀度较差的问题。因此提出了一种均衡运动原理的旋振筛,通过DEM数值模拟,从筛分效率的角度直观比较了旋振筛在常规运动和均衡运动下的筛面物料运动规律、颗粒粒度分布情况、固相筛分效率及颗粒运动速度。研究表明：均衡运动下物料向筛面周边旋转扩散更为均匀,其物料层较薄,能有效提高旋振筛的固相筛分效率及筛分颗粒的均匀度,可较好解决颗粒粒径与筛孔孔径比在0.7~1.0之间时颗粒透筛相对困难的问题。     

振动筛在大颗粒尿素生产中的应用及改进

通过对尿素振动筛在生产实际运行中的性能分析,在不影响筛分效率的前提下,更改尿素筛的安装斜度和改进尿素筛的筛网规格,增加了尿素筛的筛分能力,降低了设备成本,提高了产品品质,有效地保障装置的长周期平稳运行.     

Grade efficiency for sieve classification processes

Modelling of the screening performance for classification processes is important to obtain a first estimate for a new process in the planning phase. In this work especially the grade efficiency curves of sieve classifications with vibrating screens were examined. A sensitivity study was performed by changing the operating parameters of the sieving machine and the parameters of the charging material (i.e. mass flow, particle size, etc.). The aim was to correlate the input parameters with the grade efficiency curve of the classification process. The main aspect of the presented work is to find an appropriate method to adjust four screening parameters in a way that the measured grade efficiency curve is modelled correctly. Several methods for this adjustment step are reviewed. A sensitivity study using a tumbling screen was performed previously. It is apparent that for that study, different methods and models for the parameter adjustment need to be used. Furthermore it is shown that data reconciliation is necessary, since the mass balance of the particle streams may not be closed correctly. In summary this work is the first step to predict the screening performance of a sieving machine without material‐ and time‐consuming experiments.     

气-气快速混合模型在氯化氢灯头设计上的应用

介绍了利用横喷射流与多孔板混合模型，选用合适的理论模型设计氯化氢灯头装置。该装置集中了横喷射与多孔板混合的优点，实现氯、氢的快速混合。经生产检验显示，该装置设计合理，混合效果好，操作稳定、火焰短。     

ENHANCEMENT OF STRAUSS' SECONDARY FLOW MIXING IN THIN FILM COMMERCIAL REACTORS

Experiments involving both viscous mixing and flow visualization in complex geometries simulating thin film commercial reactors were performed. Highly complex recirculation flows of elastic polymers were reproduced and studied on a TV screen by injecting small volumes of dye (representing process catalyst) into polyvinyl acetate melt, on a blade simulator developed by us recently. High resolution motion pictures taken at 30 frames per second demonstrate that secondary flows, as predicted by Strauss' equations, fail to correct the tendency of the fluid-fluid interface to remain parallel to the velocity streamlines. This problem is further aggravated by the presence of stagnant zones at the center of the vortices. This situation often led to reaction excursions in poorly mixed regions. Specially designed notches were developed to enhance the mixing process, and these increased the interfacial area for mass transfer several fold and also reduced viscous heat dissipation at the gap between the stationary blade and the moving plate. Commercial scale tests with the new blade design corroborate the laboratory findings.

A simplified apparatus has been developed to simulate the secondary flow behavior that occurs in thin film commercial reactors. The extension of Strauss' mathematical model to the case of viscoelastic fluid enabled reactor performance improvement through high speed cinematographic studies using the simulator. The rate of recirculation in the secondary flow was shown to be proportional to the speed of the impeller; however, the center of the secondary flows was noted to be a zone of poor mixing. This was corrected through a special impeller design that destroys stagnation zones in the reactor.     

Column Dust Scrubber Based on an Orifice Plate to Intensify Gas‐Liquid Mixing

A column dust scrubber based on an orifice plate is developed for small and medium‐sized enterprises in China, which urgently need small‐volume, large‐flow scrubbers. The scrubber uses an orifice plate to evenly distribute the gas flow, which forms a uniform and stable impact on the liquid phase. As a result, dust removal via intensified gas‐liquid mixing can be achieved. A laboratory orifice plate scrubber model is developed, prototyped, and preliminarily studied considering the working process of the scrubber (mixed gas‐liquid flow pattern), liquid level, gas flow rate, pressure drop characteristics, dust removal efficiency, etc. The scrubber can achieve a good gas‐liquid mixing state when it is in a stable liquid column flow pattern. The drag coefficient of the scrubber is affected by the discharge of the gas stream to the liquid phase.     

A Microfluidic Approach to the Rapid Screening of Palladium‐Catalysed Aminocarbonylation Reactions

The evaluation and selection of the most appropriate catalyst for a chemical transformation is an important process in many areas of synthetic chemistry. Conventional catalyst screening involving batch reactor systems can be both time‐consuming and expensive, resulting in a large number of individual chemical reactions. Continuous flow microfluidic reactors are increasingly viewed as a powerful alternative format for reacting and processing larger numbers of small‐scale reactions in a rapid, more controlled and safer fashion. In this study we demonstrate the use of a planar glass microfluidic reactor for performing the three‐component palladium‐catalysed aminocarbonylation reaction of iodobenzene, benzylamine and carbon monoxide to form N‐benzylbenzamide, and screen a series of palladium catalysts over a range of temperatures. N‐Benzylbenzamide product yields for this reaction were found to be highly dependent on the nature of the catalyst and reaction temperature. The majority of catalysts gave good to high yields under typical flow conditions at high temperatures (150 °C), however the palladium(II) chloride‐Xantphos complex [PdCl₂(Xantphos)] proved to be far superior as a catalyst at lower temperatures (75–120 °C). The utilised method was found to be an efficent and reliable way for screening a large number of palladium‐catalysed carbonylation reactions and may prove useful in screening other gas/liquid phase reactions.     

The effect of vapour mixing on efficiency of large diameter distillation plates

Liquid and vapour flow maldistribution has been experimentally detected in large diameter distillation plates. Theoretical models developed to predict plate efficiency taking into account similar phenomena generally assume completely mixed vapour. This paper analyses the effect of vapour mixing on the plate efficiency for different values of stripping factor, point efficiency and liquid mixing degree and shows the remarkable influence of vapour mixing in presence of liquid maldistribution. Moreover a criterion for the prediction of the plate efficiency is suggested.     

Flooding and axial dispersion in reciprocating plate extraction columns

The flooding and axial mixing characteristics of a 15 cm diameter reciprocating plate extraction column with six different plate arrangements handling kerosene dispersed in water are reported. A general correlation for flooding in the emulsion flow regime is developed and applied to the present results and to published data on other columns and systems. Under certain conditions of flow and agitation, the axial mixing is very high because of circulation, but it can be reduced by including baffles in the plate stack.     

撞击流反应器内涡特性研究进展

撞击流技术具有良好的混合效果,广泛应用于能源、环保、化工等工程领域。由于撞击流反应器流场内存在大量无序的湍流涡结构,使其具有良好的混合效果。本文基于撞击流的混合原理,详细叙述了撞击流反应器内不同混合尺度下的混合过程以及涡的演变对混合的影响。结合实验和数值模拟等研究结果,阐述了不同类型撞击流反应器和撞击流反应器多相流场涡特性,归纳了撞击流反应器流场涡的特点。论述了撞击流反应器涡的产生和脱落机理。着重对圆柱射流、平板射流和撞击流流场内涡特性的本征正交分解（POD）分析进行总结,利用流场能量的角度揭示涡演化和消散规律。最后,对开发新型撞击流反应器、优化分析方法等研究前景进行展望。     

基于简化Bow-tie模型的LOPA场景辨识与筛选方法

场景筛选是确保保护层分析（LOPA）有效性的关键,为准确筛选出需要进行LOPA分析的场景,本文在Bow-tie模型的基础上,提出了基于最大可信场景的场景辨识及筛选方法。首先,利用事故树与事件树建立以损失事件为中心的简化Bow-tie模型辨识分析对象的潜在危害,得到危害场景列表;其次,以最大可信场景辨识方法为基础对场景筛选方法进行改进,利用改进后的筛选方法对危害场景列表进行筛选,确定场景列表中最终需要进行LOPA分析的场景;最后,将此方法应用于某商储库10⁵m³原油储罐风险分析的场景筛选中,并利用风险分析筛选软件（RAST）来验证所提方法的可行性和有效性。结果表明：所提方法能够较好地考虑设备实际运行情况,且根据企业内部的风险标准进行筛选,得到的实际筛选结果对后续的LOPA分析更具指导意义。     

外切-β-葡聚糖酶基因重组里氏木霉的筛选及其产酶性能

外切-b-葡聚糖酶是纤维素酶的重要组分之一,提高该组分的活力是增强纤维素酶协同降解性能、降低纤维素水解成本的关键。分别采用微晶纤维素琼脂平板法和滤纸崩解法,对已有的基因重组转化子进行筛选试验,获得了6个优良转化子,其滤纸崩解速率和微晶纤维素琼脂平板上的生长速率都较大。进一步在摇瓶条件下进行复筛试验,获得了外切-β-葡聚糖酶（C₁）高产转化子Trichoderma reesei ZU-101,液体培养48 h,其C₁酶活力可达18.24 U·ml^-1,是出发菌株的2.16倍;分析结果表明：重组转化子的纤维素酶体系中内切-b-葡聚糖酶和纤维二糖酶的活力与出发菌株相比变化不大,但由于外切-b-葡聚糖酶活力得到了大幅度提高,纤维素酶的总活力（滤纸酶活力FPA）也提高了61.9%。采用纤维素酶对碱预处理玉米秸秆进行酶解试验,当酶用量为20 FPIU·（g底物）^-1,水解48 h,重组转化子T.reesei ZU-101纤维素酶的酶解得率高达94.4%。本文的研究结果在可再生纤维素资源的生物转化与利用方面具有广阔的应用前景。