翅片导流板填料应用于旋转填料床的特性

For an alcohol/water system and with fin baffle packing, continuous distillation experiments were carried out in a rotating packed bed (RPB) system at atmospheric pressure. The effects of the average high gravity factor (β), liquid reflux ratio (R) and feedstock flux (F) on the momentum transfer and mass transfer were investigated. The gas phase pressure drop of RPB increased with the average high gravity factor, liquid reflux ratio and feedstock flux, which was 13.55-64.37 Pa at β of 2.01-51.49, R of 1.0-2.5, and F of 8-24 L&;#8226;h－1 for a theoretical tray in the RPB with fin baffle packing. The investigation on the mass transfer in the RPB with different packings showed that the number of transfer units of RPB with a packing also increased with the average high gravity factor, reflux ratio and feedstock flux. It is found that the fin baffle packing (packing III) presents the best mass transfer performance and lowest pressure drop for the height equivalent to a theoretical plate (HETP), which is 6.59-9.84 mm.     

Hydrodynamics of three-phase fluidization of homogeneous ternary mixture in a conical conduit——Experimental and statistical analysis

Hydrodynamics of conical fluidized bed differ from that of columnar beds by the fact that a velocity gradient exists along the axial direction of the bed.The gas–liquid–solid fluidized bed has emerged in recent years as one of the most promising devices for three-phase operations.Such a device is of considerable industrial importance as evident from its wide applications in chemical,refining,petrochemical,biochemical processing,pharmaceutical and food industries.To explore this,a series of experiments have been carried out for homogeneous well-mixed ternary mixtures of dolomite of varying compositions in a three-phase conical fluidized bed.The hydrodynamic characteristics determined included the bed pressure drop,bed fluctuation and bed expansion ratios.The single and combined effects of operating parameters such as superficial gas velocity,superficial liquid velocity,initial static bed height,average particle size and cone angle on the responses have been analyzed using response surface methodology(RSM).A 25 full factorial central composite experimental design has been employed.Analysis of variance(ANOVA) showed a high coefficient of determination value and satisfactory prediction second-order regression models have been derived.Experimental values of bed pressure drop,bed fluctuation and bed expansion ratios have been found to agree well with the developed correlations.     

旋转填料床中硝酸吸收NO_x的实验研究(英文)

Absorption of NOx into nitric acid solutions was studied in the presence of ozone by using a rotating packed bed (RPB) contactor. The influences of operating parameters, such as high gravity number, amount of ozone, gas velocity, liquid spray density and inlet concentration of NOx, on the removal efficiency of NOx were investigated, among which the high gravity number and ozone amount are more important. Ozone was introduced to oxidize HNO2 to HNO3 to prevent the decomposition of HNO2 in the liquid phase. The high gravity number presents the effective external force for enhancing the mass transfer of ozone from gas phase to liquid phase. Under the experimental condition, the removal efficiency of NOx is higher than 90% and the concentration of nitric acid product exceeds 45%.     

Experimental Investigation of Pressure Drop Hysteresis in a Cocurrent Gas–Liquid Upflow Packed Bed

Extensive experimental work on hysteresis in a cocurrent gas–liquid upflow packed bed was carried out with three kinds of packings and the air–water system. However, only when packed with small glass beads (f1.4 mm) was the bed pressure drop hysteresis observed. Two more liquids with different liquid properties were employed to further examine the influence of parameters on pressure drop hysteresis. The similarity of pressure drop hysteresis in packed beds was concluded in combination of experimental evidence reported in literature.     

整体式床层中液体分布与气-液传质的关系

With a particular focus on the connection between liquid flow distribution and gas-liquid mass transfer in monolithic beds in the Taylor flow regime, hydrodynamic and gas-liquid mass transfer experiments were carried out in a column with a monolithic bed of cell density of 50 cpsi with two different distributors (nozzle and packed bed distributors). Liquid saturation in individual channels was measured by using self-made micro-conductivity probes. A mal-distribution factor was used to evaluate uniform degree of phase distribution in monoliths. Overall bed pressure drop and mass transfer coefficients were measured. For liquid flow distribution and gas-liquid mass transfer, it is found that the superficial liquid velocity is a crucial factor and the packed bed distributor is better than the nozzle distributor. A semi-theoretical analysis using single channel models shows that the packed bed distributor always yields shorter and uniformly distributed liquid slugs compared to the nozzle distributor, which in turn ensures a better mass transfer performance. A bed scale mass transfer model is proposed by employing the single channel models in individual channels and incorporating effects of non-uniform liquid distribution along the bed cross-section. The model predicts the overall gas-liquid mass transfer coefficient with a relative error within ±30%.     

Numerical simulation and experimental study of the characteristics of packing feature size on liquid flow in a rotating packed bed

Rotating packed bed has high efficiency of gas–liquid mass transfer. So it is significant to investigate fluid motion in rotating packed bed. Numerical simulations of the effects of packing feature size on liquid flow characteristics in a rotating packed bed are reported in this paper. The particle image velocimetry is compared with the numerical simulations to validate the turbulent model. Results show that the liquid exists in the packing zone in the form of droplet and liquid line, and the cavity is droplet. When the radial thickness of the packing is less than 0.101 m, liquid line and droplets appear in the cavity. When rotational speed and radial thickness of the packing increase, the average diameter of the droplets becomes smaller, and the droplet size distribution becomes uniform. As the initial velocity of the liquid increases, the average droplet diameter increases and the uniformity of particle size distribution become worse. The droplet velocity increases with the radial thickness of the packing increasing, and gradually decreases when it reaches the cavity region. The effect of packing thickness is most substantial through linear fitting. The predicted and simulated values are within ±15%. The cumulative volume distribution curves of the experimental and simulated droplets are consistent with the R-R distribution.     

Mass transfer characteristics in a rotating packed bed with split packing

The rotating packed bed (RPB) with split packing is a novel gas–liquid contactor, which intensifies the mass transfer processes controlled by gas-side resistance. To assess its efficacy, the mass transfer characteristics with adjacent rings in counter-rotation and co-rotation modes in a split packing RPB were studied experimentally. The physical absorption system NH3–H2O was used for characterizing the gas volumetric mass transfer coeffi-cient (kyae) and the effective interfacial area (ae) was determined by chemical absorption in the CO2–NaOH sys-tem. The variation in kyae and ae with the operating conditions is also investigated. The experimental results indicated that kyae and ae for counter-rotation of the adjacent packing rings in the split packing RPB were higher than those for co-rotation, and both counter-rotation and co-rotation of the split packing RPB were superior over conventional RPBs under the similar operating conditions.     

新一代的乱堆填料——梅花扁环

The hydrodynamics and mass transfer of Plum Flower Mini Ring(PFMR),Pall Ring and Intalox Saddle were studied in a 600mm diameter column with air-oxygen-water system over a wide range of liquid loasds.It was shown from the experiments that PFMR had much lower resistance,larger throughput and higher mass transfer efficiency than Pall Ring and Intalox Saddle.It was clear from the comparison that existing equations could not predict the performance of packings very well at high liquied loads.Therefore,new semi-empirical equations of pressure drop,flooding gas velocity and height of transfer unit(HTU)were proposed based on the experimental data.     

旋转填充床内高黏介质脱除有机挥发组分过程强化

The removal of a volatile organic compound (VOC) from high viscous liquid was carried out in a rotating packed bed (RPB) in this study. The mixed liquid of syrup and acetone was used as simulated high viscous polymer solution with acetone as the volatile compound. The influence of the rotating speed of RPB, liquid viscosity, liquid flow rate, vacuum degree, and initial acetone content in the liquid on acetone removal efficiency was investigated. The experimental results indicated that the removal efficiency increased with increasing rotating speed and initial acetone content in the viscous liquid and decreased with increasing liquid viscosity and flow rate. It was also observed that acetone removal efficiency increased with an increasing vacuum degree and reached 58% at a vacuum degree of 0.1 MPa. By the comparison with a flash tank devolatilizer, it was found that acetone removal ef-ficiency in RPB increased by about 67%.     

旋转填充床中沉淀过程的模型及实验验证(英文)

A mixing-precipitation model based on the modified coalescence-redispersion model was presented to describe the flow, mixing, nucleation and growth in a rotating packed bed (RPB). The model was coupled with population balance, mass balance and crystallization kinetics. It predicted well the influence of coalescence probability, which represents the mixing intensity among drop-lets, on the particle number density, supersaturation and mean particle size of the produced precipitates. The effects of the radial thickness of packing, liquid flow rate and rotating speed on the product particle size were also investigated. The results indicate that the needed radial length of packing is short for sparingly soluble substance precipitation (about 40-50 mm in this work), and the mean particle size of precipitates decreases with the increase of rotating speed and liquid flow rate, respectively. The validity of this model was verified by experiment on BaSO4 precipitation in RPB.     

折流式超重力旋转床液泛和气相压降的实验研究

折流式超重力旋转床是一种新型高效的气液传质设备。液泛和气相压降是超重力旋转床流体力学的重要特征。实验以空气-水为物系,对转子直径为288mm,高度为55mm的折流式旋转床进行了气相压降和液泛实验。实验表明：随着转速和液流量的增加,液泛气速减小,折流式旋转床更容易液泛。气相压降随气量、转速、液量的增加而增大,随气量和转速增大的趋势比较明显,随液量增大的趋势比较缓慢。     

折流式旋转床静圈对其性能的影响

折流式旋转床是一种新型的超重力旋转床,其核心部件是动、静结合的转子,转子由安装了动圈的动盘和安装了静圈的静盘上下相互嵌套而成。本实验中使用了一个常规的折流式转子（转子Ⅰ）和一个具有较短静圈的折流式转子（转子Ⅱ）,在常压下分别以乙醇-水体系和空气-水体系对两个折流式转子进行了传质性能与流体力学实验,考察了静圈对折流式旋转床的传质、压降和功耗的影响。结果表明,静圈能明显强化传质过程,与转子Ⅰ相比,转子Ⅱ理论塔板数大约降低了的50%;转子Ⅰ的传质效率随转速的增大而增大,当转子的转速从400 r/min增加到1200 r/min,转子Ⅰ的传质效率增大了约40%,而转子Ⅱ的理论塔板数变化不明显;静圈使折流式转子具有较大的压降和功耗,转子Ⅱ的压降为转子Ⅰ的20%～50%,轴功率为转子Ⅰ的60%～80%。     

折流式超重力旋转床转子结构对气相压降的影响

折流式超重力旋转床是继旋转填料床之后出现的一种新型高效的气液传质设备.今采用空气-水系统对折流式旋转床进行了气相压降实验,考查了折流式转子结构对气相压降的影响,建立了折流式旋转床干床气相压降的理论模型.实验结果表明:折流式旋转床转子结构对气相压降影响较大,在动静折流圈结构不变的情况下,动静盘垂直间距存在某一最优值,通过实验得到了实验中所用的折流式旋转床的最佳转子高度为90 mm,实验也验证了旋转床设计时采用的等通流面积原则是符合气体运动规律的;干床压降理论模型的计算结果与实验值符合较好,为建立湿床压降模型奠定了基础.     

Performance of a rotating zigzag bed—A new HIGEE

As a new kind of rotating equipment, rotating zigzag bed (RZB) is structurally unique and has many superior features. The RZB is characterized by a rotor coaxially combining a rotating disc with a stationary disk. Compared with a conventional rotating packed bed (RPB), the RZB can function without liquid distributors, eliminate one dynamic-seal, and easily accommodate and accomplish intermediate feeds in continuous distillation processes. The RZB also effectively increases the contact time of gas and liquid phases and thus, enhances the mass transfer capacity. In this work, the principles of the RZB are presented. The hydraulic and mass transfer performance of the RZB was investigated. Experimental results showed that the pressure drop of the RZB increases with the increase of the rotational speed and the gas flow rate, but decreases with the increase of the liquid flow rate. A semi-empirical equation was proposed to correlate the pressure drop data with good agreement. The mass transfer efficiency of the RZB decreases with the increase of the reflux rate at lower reflux rate, but levels off at higher reflux rate. The number of theoretical plates of the RZB increases with the increase of rotational speed of the rotor. However, at a higher rotational speed, this trend is not obvious. In addition, some considerations for further work are discussed.     

折流式旋转床有效功耗的初步研究

折流式旋转床是一种新型的同心圈式超重力设备,电机功率消耗是折流式旋转床设计时需要考虑的重要因素.本文对折流式旋转床的有效功耗进行了初步的实验研究,并提出了一种新的有效功耗计算方法,为旋转设备功耗研究和折流式旋转床工业应用提供了一定基础.折流式旋转床有效功耗可以分成两部分,即分散液体功耗和加速液体功耗.通过理论分析,得到了折流式旋转床有效功耗的计算模型.实验以水为介质,在不同液量和转速下测得有效功耗.结果表明,转速一定时,有效功耗随着液量的增加近似呈线性增加,且转速越大,有效功耗随液量增加越快.通过对实验数据的回归,得到单个同心圈转子有效功耗的计算模型,实验值与回归计算值相对偏差基本在20%以内.通过对包含4个同心圈转子的折流式旋转床有效功耗的验证结果可知,4个动圈有效功耗计算值的总和比实验测量值高20%左右,对折流式旋转床的工程放大有一定意义.     

新型径向叶片式旋转床压降分析及气相流场模拟

针对折流式旋转床压降高、能耗大的问题,提出了一种新型超重力旋转床设备--径向叶片式旋转床。首先,对该旋转床的压降进行了理论分析和建模,并利用水-空气体系进行了实验研究。通过改变气量、转速和液量探究了新型径向叶片式旋转床压降的变化规律,结果表明压降随气量、转速和液量的增加而增加,且随着气量和转速的增加,液量对压降的贡献逐渐减小。压降模型的预测值与实验数据的相对偏差基本在10%以内,表明模型可以较好地预测新型径向叶片式旋转床的压降。另外,通过计算流体力学（CFD）软件的模拟获得了旋转床内气相流场和压力分布的结果,发现转子内压降是总压降的主要部分;气体进入转子后会因叶片作用使得周向速度变大,并在转子外缘处达到最大值;气体的进口流速将会影响旋转床内的气相分布。利用实验数据对CFD模拟结果进行了验证,两者的相对偏差在10%左右。     

同心圈式超重力旋转床液泛模型

同心圈式超重力旋转床是一种新型超重力旋转床。液泛是超重力旋转床流体力学的重要特征。同心圈式超重力旋转床液体分布器和转子内缘之间的环形空间内的液滴被气体夹带,液滴受到离心力和气体曳力的作用,通过建立微分方程可获得液滴径向速度为零时的液滴运动径向距离。当该径向距离小于环形空间的径向距离,此时产生雾沫夹带液泛。由此建立同心圈式超重力旋转床雾沫夹带液泛模型。实验以空气和水为物系,测定了转子直径为1000 mm、高度为100 mm的同心圈式超重力旋转床在不同转速和表观液速下气体进口和出口之间的气相压降随表观气速的变化。气相压降随表观气速的增大先缓慢增大后快速增大。用表观气速对气相压降求导和目测旋转床中心气体出口处出现大量液体被气体夹带来确定液泛点气速。通过液泛点气速求得雾沫夹带液泛模型的系数k,并对该系数k进行关联。该雾沫夹带液泛模型的计算值和实验值吻合很好,平均偏差为3.1%。该模型优于Sherwood液泛模型,对同心圈式超重力旋转床的工业应用提供了必要的设计依据。     

网板填料复合旋转床的流体力学与传质性能

开发了一种新型的气液接触设备——网板填料复合旋转床。常压下以空气-水物系和乙醇-水物系在网板填料复合旋转床中进行流体力学与传质性能实验,考察了气液流量和转子转速对网板填料复合旋转床压降和传质性能的影响。实验结果表明,气体流量和转子转速的增大均使干、湿床气相压降增大;液体流量的增加对湿床压降的影响不明显。回流量和转速的增加均使等板高度减少至一定值后几乎不变。网板填料复合旋转床具有通量大、效率高、压降小的特点。     

折流式旋转床持液量的研究

将折流式旋转床分成若干液体流动区,计算流动区内动、静圈壁上液膜及动、静圈之间液滴的运动时间,在此基础上建立折流式旋转床持液量模型. 以空气-水为物系,在直径300 mm、高51 mm的折流式旋转床中进行实验,分别测得不通和通空气时转子的持液量,用实验数据拟合出持液量模型参数. 结果表明,转子持液量随液量和气量增加而增加,随转子转速增加而减小,高转速下气量对持液量的影响明显减弱. 折流式旋转床不通气持液量为2.35%~3.68%,是普通丝网旋转填料床不通气持液量的1.32~2.06倍.     

同心圈式旋转床的精馏实验

同心圈式旋转床是一种新型超重力旋转床,其转子由一组多孔板同心圈构成,相邻同心圈之间无填料或填充填料。液体在同心圈上存在滑移效应,滑移效应能够增大气液比表面积和改善液体在同心圈上的周向分布。本文采用乙醇-水物系对转子直径为1.0m的大型同心圈式旋转床进行全回流常压精馏实验,实验选用无丝网填料同心圈和填充丝网填料同心圈两种转子。实验结果表明,本大型同心圈式旋转床具有较大的处理量,其等板高度（HETP）随F因子和超重力因子的增大先减小后增大。填充丝网填料同心圈转子的HETP小于无丝网填料同心圈转子。在超重力因子为563.4和F因子为5.5(m/s)(kg/m³)^0.5时,填充丝网填料同心圈转子的等板高度达到最小值51.5mm,每块理论板气相压降为1.5kPa。通过实验数据拟合得到了两种同心圈转子的HETP经验关联式。与折流式旋转床相比,同心圈式旋转床具有高通量和低压降的优点。