倒锥形填料筐精馏塔板的性能研究

提出了一种新型高效塔板——倒锥形填料筐新型精馏塔板(RTPLT),在冷模塔内对该塔板的流体力学性能和塔内液体停留时间分布情况进行了研究。由实验数据关联得到了干板压降、湿板压降和漏液率的经验式。结果表明:RTPLT具有塔板压降低、雾沫夹带小、处理能力大等优点,其塔内液体停留时间分布的主要因素是液体流量。     

板波纹填料塔中的液体分布

根据透明有机波纹填料片内染色液体流动分布的实验研究 ,提出了板波纹填料塔内液体流动模型 ,并对真实填料塔进行了实例计算 ,所得结果对于填料塔实际操作具有指导意义     

隔壁塔内半圆填料层中壁流与返混特性研究

在填料塔三参数壁流模型的基础上,提出了应用于隔壁塔半圆型填料层的壁流模型。通过实验对模型参数进行了估计。模型计算值与实验值吻合较好。在内径为580 mm、高2800 mm的半圆冷模塔内,常温常压下以空气-水为介质,测取了散堆填料的壁流曲线,分析了气液速率变化对壁流的影响。以氯化钠溶液为示踪剂,通过脉冲注入扰动响应技术获得停留时间分布曲线。发现气液速率变化均对停留时间分布产生不同程度影响。同时比较了同一填料层高度塔壁区和整体区的平均停留时间,在壁流充分发展阶段,塔壁区的平均停留时间明显小于整体区。从另一方面量化了壁流效应的影响。应用线性回归得到单相流和气液逆流时计算Pe_d的关联式。对于新型填料及塔内件的开发、改进隔壁塔的设计方法,从而实现安全有效放大具有参考意义。     

表面张力对规整填料内停留时间的影响

为考察表面张力对不锈钢板波纹规整填料内液体停留时间的影响,采用脉冲注入Na Cl溶液的电导示踪技术,分别测量了体积分数10%的乙醇水溶液和水2种物系在500Y和750Y 2种填料不同出口处的电导率。根据实时记录的电导率计算得到了不同出口处的液体平均停留时间。实验结果表明:液体平均停留时间随着表面张力的降低而增加,随着填料比表面积的增加而增加,随着液体负荷的增加而降低。另外,出口位置对称的液体平均停留时间基本相同,紧靠壁面出口的平均停留时间要显著大于其他出口的。     

海水脱硫散堆填料塔的数值模拟及传质计算

采用体积平均法建立了描述散堆填料塔内气、液两相的流动模型;在双膜理论的基础上建立了平均体积传质模型。通过数值计算,获取了在不同液气比下塔内流体速度、孔隙率分布、压力分布及脱硫效率,并就压力损失和脱硫效率与实验值进行了对比,预测值与实验值吻合较好,趋势完全一致。分析填料塔内海水的速度分布矢量图和填料塔中间高度断面上的速度分布图发现,靠近壁面处存在着显著的壁流现象,并在沿流方向上液体有向壁区积聚的趋势,壁流现象变得更严重。由3种填料径向孔隙率分布图可看出,近壁面处的孔隙率明显高于中间区域,表明这是形成壁流的原因所在。     

低喷淋密度下P-S复合塔板的持液特性研究

填料-筛板复合塔板是一种被用于高气液比吸收处理过程的塔内构件,其持液量与液相停留时间对传质传热具有重要影响,为此进行了相关性能的研究.测定分析表明:P-S复合塔板的持液量可通过填料液膜区持液和浸润填料区持液两部分进行估算,停留时间可在实验基础上据模型计算.同时,在单因素实验条件下,P-S复合塔板的动持液量随喷淋密度的增...     

气液两相逆流状态下金属板波纹填料塔内液体流动分布

填料塔内液体流动分布状况直接关系到塔内气液两相的有效接触,影响塔的操作性能.由于液体分布不良,造成填料塔内局部区域的气液比与全塔宏观的气液比有显著差别,从而大大降低塔的总传质效率.因此,填料塔内的液体分布     

激光光导纤维技术在填料塔研究中的应用

本文建立了一种新的测试装置——激光光导纤维检测仪和微型计算机实时采集数据系统。在装有φ38mm陶瓷矩鞍环填料的1m直径填料塔中,采用干扰-响应技术和空气/水系统,同时测定16个点的液体停留时间分布。实验平均停留时间分布图揭示了填料塔液体有一个优先向塔壁流动的趋势。     

气液两相逆流状态下金属板波纹填料塔内液体流动分布

<正>填料塔内液体流动分布状况直接关系到塔内气液两相的有效接触,影响塔的操作性能.由于液体分布不良,造成填料塔内局部区域的气液比与全塔宏观的气液比有显著差别,从而大大降低塔的总传质效率.因此,填料塔内的液体分布     

基于液体弥散理论的规整填料塔液体扩散数值模拟

规整填料塔内液体弥散规律的研究对于气液吸收塔的布液装置设计、填料高度确定以及填料类型优选具有重要理论意义,目前关于液体弥散机理的理论描述和模型建立较为有限,本文为实现填料塔内液体扩散现象的准确预测,引入液体弥散机理。规整填料采用多孔介质简化,在考虑了机械弥散力、气液拖曳力、多孔介质阻力等基础上建立了二维CFD模型,模拟结果与实验结果吻合较好。在此基础上研究了液体扩散系数S、气体入口速度和液体入口速度对液体分布的影响。通过研究得出液体弥散机理中毛细管弥散作用影响较小,主要以机械弥散作用为主;液体扩散系数和液体入口速度对液体分布的影响显著,S/Dr的最佳比例为2,气体入口速度对液体分布影响很小。研究结果对其他类型填料的模拟研究有重要借鉴作用。     

Radioisotope tracer study in trickle bed reactors

The residence time distribution (RTD) of liquid phase in trickle bed reactors has been measured for air‐water system using radioisotope tracer technique. Experiments were carried out in a glass column of internal diameter of 0.152 m packed with glass beads and actual catalyst particles of two different shapes. From the measured RTD curves, mean residence time of liquid was calculated and used to estimate liquid holdup. The axial dispersion model was used to simulate the experimental data and estimate mixing index, ie. Peclet number. The effect of liquid and gas flow rates on total liquid holdup and Peclet number has been investigated. Results of the study indicated that shape of the packing has significant effect on holdup and axial dispersion. Bodenstein number has been correlated to Reynolds number, Galileo number, shape and size of the packing.     

Liquid phase residence time distribution for a two-phase countercurrent flow in a packed column with a novel internal

The liquid phase residence time distribution (RTD) for gas–liquid countercurrent flow in a packed column with a novel internal was measured by conductivity measurements and an air–water system. The RTD of a liquid tracer is well represented by the ADM and PDE models. At lower gas flow rates, the Peclet number of the liquid in the packed column with the internal is lower than that without the internal; at higher gas flow rates, it is vice versa, especially with an internal with a higher volume fraction. The distribution of the liquid RTD can be improved by using suitable geometric parameters of the internal to give a larger volume fraction and a lower stage height.     

用随机过程模拟填料塔液体的流动分布

本文用状态离散(?)时间离散的马尔可夫过程来模拟颗粒填料塔液体的流动分布.结果表明,用随机过程的理论来阐明填料塔液体的随机流动和转移过程,更能准确地反映过程的本质.     

A model for mass transfer in packed towers: mass transfer with controlling resistance in the gas phase

A model for mass transfer in the liquid phase in packed towers, proposed in a previous work[5], is employed in the case of mass transfer with controlling resistance in the gas phase. On taking into account the semistagnant liquid pockets by the liquid residence time distribution function, relationships are established between the volumetric mass transfer coefficients in different operations: evaporation, physical absorption, chemical absorption. The calculated values of the mass transfer coefficients agree well with experimental data.     

波纹板规整填料塔液体分布

将填料单元处理成立体节点网,根据节点网内网线液流和节点液流各自的运动方式建立了填料单元的液体分布模型.通过将填料与塔壁间的液体交换规范成填料节点网与塔壁节点网间的液量传递建立了填料单元对应塔壁区的流体分布模型.提出了规整填料塔液体分布问题的边界条件.2个描述填料单元及其对应塔壁区液体分布的数学模型与2类边界条件共同构成了波纹板规整填料塔的液体分布模型.采用单纯形法对3个模型参数进行了估计.模型计算结果与实验数据一致,表明模型能合理地描述波纹板规整填料塔的液体分布性能.     

Axial dispersion in a rectangular bubble column

This paper presents the results of an experimental study on the gas holdup and the liquid phase axial dispersion coefficient in a narrow packed and unpacked rectangular bubble column. In both cases the gas and liquid flow rates were varied and the data were obtained by employing standard tracer technique. The gas holdup and the axial dispersion coefficient for both the packed and unpacked columns were found to be dependent on the gas and liquid flow rates. For given gas and liquid velocities and a given packing size in the case of the packed column, the rectangular column gave significantly higher dispersion coefficients than a cylindrical column of the equivalent cross sectional area. This result agrees very well with the one predicted by the velocity distribution model. The correlations for the Peclet number, the axial dispersion coefficient, and the fluid holdup for both the unpacked and packed bubble columns are presented.     

金属波纹板规整填料塔中液体有效流速

<正>填料塔以压降小、通量大、持液量小、分离效率高等优点广泛应用于精馏和吸收等单元操作中。填料塔中液体的流体力学行为对精馏等传质过程有重要影响,而液体在填料塔中的有效流速是液体流体力学行为的重要参数。例如描述填料塔中液相返混通常用一维或二维扩散模型,其中的有效流速就是重要的方程参数;要精确描述填料塔中相界面的传质行为,液相的真实流速也是关键性的参数。目前一般采用Bravo提出的公式来计算规整填料塔内液体的有效速度     

The Relationship Between Hysteresis and Liquid Flow Distribution inTrickle Beds

Experiments were conducted on a trickle bed with 0.283 m ID to eluddate the relation-ship between hysteretic phenomena and liquid distribution. The hysteresis of pressure drop and the variance of radial liquid distribution were observed simultaneously. Residence time dlstribu-tion (KTD), holdup and mean residence time (RT) of liquid phase were also found to demonmtrate hystereels of the same nature. RTD, liquid holdup and mean RT calculated with a simple model from the distribution of liquid flow rate show chaxacteristic consistant with the experlmeataJ data, suggesting that the hyteretic phenomena originate from the multiplicity and nonuniformity of liquid flow distribution.