Prediction of dispersed phase holdup in pulsed disc and doughnut solvent extraction columns under different mass transfer conditions

Using experimental data from a number of pulsed disc and doughnut solvent extraction columns,a unified correlation for the prediction of dispersed phase holdup that considers the effects of mass transfer is presented.Pulsed disc and doughnut solvent extraction columns(PDDC) have been used for a range of important applications such as uranium extraction and nuclear fuel recycling.Although the dispersed phase holdup in a PDDC has been presented by some researchers,there is still the need to develop a robust correlation that can predict the experimental dispersed phase holdup over a range of operating conditions including the effects of mass transfer direction.In this study,dispersed phase holdup data from different literature sources for a PDDC were used to refit constants for the correlation presented by Kumar and Hartland [Ind.Eng.Chem.Res.,27(1988),131–138] which did not consider the effect of column geometry.In order to incorporate the characteristic length of the PDDC(i.e.the plate spacing),the unified correlation for holdup proposed by Kumar and Hartland based on data from eight different types of columns [Ind.Eng.Chem.Res.,34(1995) 3925–3940] was refitted to the PDDC data.New constants have been presented for each holdup correlation for a PDDC based on regression analysis using published holdup data from PDDCs that cover a range of operating conditions and physical properties and consider the direction of mass transfer.

Effects of internals on phase holdup and backmixing in a slightly-expanded-bed reactor with gas–liquid concurrent upflow

Five different internals were designed,and their effects on phase holdup and backmixing were investigated in a gas–liquid concurrent upflow reactor where the spherical alumina packing particles of three diameters(3.0,4.5 and6.0 mm)were slightly expanded under the conditions of varied superficial gas velocities(6.77×10-2-3.61×10-1 m·s-1)and superficial liquid velocities(9.47×10-4-2.17×10-3 m·s-1).The experimental results show that the gas holdup increases with the superficial gas velocity and particle size,opposite to the variational trend of liquid holdup.When an internal component is installed amid the upflow reactor,a higher gas holdup,a less liquid holdup and a larger Peclet number characterizing the weaker backmixing are obtained compared to those in the bed without internals under the same operating conditions.Additionally,the minimal backmixing is observed in the reactor equipped with the internals with a novel multi-step design.Finally,empirical correlations were proposed for estimating gas holdup,liquid holdup and Peclet number with the relative deviations within 11%,12%and 25%,respectively.

PHASE HOLDUP AND LIQUID DISPERSION IN GAS-LIQUID-SOLID CIRCULATING FLUIDIZED BEDS

Axial and radial profiles of gas and solids holdups have been studied in agas-liquid-solid circulating fluidized bed at 140mm i.d..Experimental results indicate that the axialand radial profiles of gas and solids holdups are more uniform than those in a conventionalfluidized bed.Axial and radial liquid dispersion coefficients in the gas-liquid-solid circulating fluidizedbed are investigated for the first time.It is found that axial and radial liquid dispersioncoefficients increases with increaes in gas velocity and solids holdup.The liquid velocity has littleinfluence on the axial liquid dispersion coefficient,but would adversely affect the redial liquiddispersion coefficient.It can be concluded that the gas-liquid-solid circulating fluidized bed hasadvantages such as better interphase contact and lower liquid dispersion along the axial directionover the expanded bed.

基于GA的RBF神经网络气液两相流持液率预测模型优化

为了提高气液两相流持液率预测精度,针对传统径向基函数(RBF)神经网络预测气液两相流持液率网络拓扑结构困难和收敛速度慢等问题,提出一种基于遗传算法(GA)优化径向基函数神经网络的气液两相流持液率预测模型。通过系统聚类算法和灰色关联度分析(GRA)对收集的实验数据进行处理,优选出最优模型特征,同时结合遗传算法确定了RBF神经网络结构参数。基于室内实验数据进行训练,并与常用于持液率预测的反向传播(BP)神经网络、GA-BP神经网络及RBF神经网络进行对比,评估了模型的准确性及可行性。结果表明:GA-RBF神经网络模型均方误差为0.0017,均方根误差为0.0416,平均绝对误差为0.0281,拟合度为0.9483。相较于其他神经网络模型,该预测模型表现出更高的计算精度和更强的泛化能力。

油水环状流截面相含率超声衰减法测量

为研究超声衰减法测量油水环状流截面相含率问题,采用COMSOL仿真软件建立油水环状流模型,选择超声传感器结构尺寸6mm和超声发射频率1MHz进行研究,通过分析油水环状流超声衰减特性,确定油水环状流的超声衰减系数与截面含油率关系,并获得线性关系的测量范围。在此基础上进一步研究非理想环状流相关参数对超声衰减特性的影响,并提出将非理想环状流差别阈限用于定量评价非理想环状流因素对于理想环状流超声衰减法的影响,获得非理想环状流差别阈限±10%以内同心度和椭圆度的变化范围。最后开展了油水环状流静态验证实验。研究结果表明:油水环状流截面相含率在5%~30%范围内,与超声衰减系数呈线性关系,同时在此范围内,非理想环状流差别阈限在±10%以内的同心度和椭圆度变化范围分别为0.75~1和0~5%,实验结果和仿真模拟结果具有近似的上升趋势。

低含水油水两相流等效介电常数模型

电容法测油水两相流含水率在油田的地面油水计量及井中的产出剖面分层测试中都得到广泛应用。持水率(水相体积分数)的测量需要建立油水两相流持水率与传感器电容的关系,为此需要建立混相等效介电常数与持水率的理论模型或经验模型。由于油井采出的地层水以及地面实验室标定所用的自来水在低频和中频时均具有良好导电性,因此,单纯考虑介电性而不考虑导电性会对持水率测量的准确性产生显著影响。基于电介质极化的有效电场理论,在低含水且油水状态为精细泡状流条件下,将水视为良导体,建立了油水两相流等效介电常数模型。按此模型,油水两相流的等效介电常数只取决于持水率和油相介电常数,与水相介电常数以及水相电导率无关,初步实验验证了模型正确。该研究对于油为连续相时油水两相流的含水率传感器的设计和现场应用具有重要意义。

A method and device for online magnetic resonance multiphase flow detection

Most multiphase flow separation detection methods used commonly in oilfields are low in efficiency and accuracy,and have data delay.An online multiphase flow detection method is proposed based on magnetic resonance technology,and its supporting device has been made and tested in lab and field.The detection technology works in two parts:measure phase holdup in static state and measure flow rate in flowing state.Oil-water ratio is first measured and then gas holdup.The device is composed of a segmented magnet structure and a dual antenna structure for measuring flowing fluid.A highly compact magnetic resonance spectrometer system and intelligent software are developed.Lab experiments and field application show that the online detection system has the following merits:it can measure flow rate and phase holdup only based on magnetic resonance technology;it can detect in-place transient fluid production at high frequency and thus monitor transient fluid production in real time;it can detect oil,gas and water in a full range at high precision,the detection isn’t affected by salinity and emulsification.It is a green,safe and energy-saving system.

搅拌槽内两种桨型组合固液悬浮的数值模拟

本文对工业搅拌罐内原搅拌桨型组合和改造的搅拌桨型组合产生的固液两相流动进行了数值模拟,通过对原搅拌方案和改造后的搅拌方案搅拌罐内所形成的流场、固含率分布以及功率消耗等方面的分析,发现改造方案底层桨叶排出流体的倾斜角更大,形成的搅拌循环更高。原方案搅拌罐内底部固含率很高,从下往上固含率逐渐降低,而搅拌桨型组合改造方案能够形成比较均匀的固含率。改造方案的固液悬浮效果更好,并且改造后的搅拌功率没有增加。

A Model for Predicting Holdup and Pressure Drop in Gas- Liquid Stratified Flow

The time-dependent liquid film thickness and pressure drop were measured by using parallel-wire conductance probes and capacitance differential-preesure transducers. Applying the eddy viscosity theory and an appropriate correlation of interfacial sear stress,a new two-dimensional separated model of holdup and pressure drop of turbulent/turbulent gas-liquid stratified flow was presented. Prediction results agreed well with experimental data.

Investigation on Liquid Holdup in Vertical Zero Net-Liquid Flow

Zero net-liquid flow (ZNLF) is a special case of upward gas-liquid two-phase flow. It is a phenomenon observed as a gas-liquid mixture flows in a conduit but the net liquid flow rate is zero. Investigation on the liquid holdup of ZNLF is conducted in a vertical ten-meter tube with diameter of 76 mm, both for Newtonian and non Newtonian fluids. The gas phase is air. The Newtonian fluid is water and the non-Newtonian fluids are water-based guar gel solutions. The correlations developed for predicting liquid holdup on the basis of Lockhart-Martinelli parameter are not suitable to ZNLF. A constitutive correlation for the liquid holdup of vertical ZNLF was put forward by using the mass balance. It is found that the liquid holdup in ZNLF is dependent on both the gas flow rate and the flow distribution coefficient.

水平井油水两相流阵列电磁波持水率计算方法及应用

准确求取水平井多相流持水率和反演井筒流体分布是揭示水平井开发动态的关键基础,以国产阵列电磁波持水率计为切入点开展研究,在对比分析现有阵列持水率定量计算方法基础上,提出了一种基于阵列探头径向投影中点切分面积计算持水率方法,同时对比建立了水平井筒油水两相流高、中、低含水率条件流体介质分布反演方法。研究表明,新方法计算水平井持水率平均绝对误差为4.43%,相对误差为16.34%,明显优于目前采用的权系数法和径向等高面积法;同时,高、中、低含水条件水平井筒流体分布反演以高斯径向基函数法和多元线性法最为匹配,研究成果为矿场水平井多相流生产动态评价奠定基础。

水平井气水两相阵列光纤持率计实验及解释方法研究

针对低产水平井井内流体流型不易预测的问题,在分析阵列光纤持率计测井原理及各传感器响应情况的基础上,借助多相流动模拟实验设备进行模拟实验研究,利用实验数据对比研究距离反比加权插值算法和高斯径向基插值算法这两种适用于低产水平井气水两相流流型的持率计算方法。利用空气和自来水模拟井下气水条件,分别设置气、水流体总流量300 m^(3)/d和500 m^(3)/d,每个流量条件下的含水率分别是15%、30%和80%,实验包括单相刻度实验和气水两相流流型实验。研究结果表明,距离反比加权插值算法的相对误差小于15%,而高斯径向基插值算法的相对误差小于10%。表明高斯径向基插值算法在低产水平井情况下适用于处理解释阵列光纤持率计测井数据。

海上油田水平井阵列电容持水率计算方法

水平井的井筒持水率是产出剖面测井解释中的关键参数,如何准确获取和计算水平井井筒持水率对海上油田水平井动态评价、稳油控水尤为重要。通过油水两相物理模拟实验,明确阵列电容持水率计对不同流型的适用性,针对水平井典型分层流提出面积平均法和微元积分法计算井筒持水率。该持水率与实验真实井筒持水率的误差分析表明,考虑仪器截面积的微元积分法计算的井筒持水率精度更高。在不同含水率条件下,其计算的井筒持水率相对误差均小于9%,满足现场应用的精度需求。经过现场测井资料对比分析,微元积分法计算的持水率与剩余油饱和度测井的含水饱和度解释结论相互印证出水层位。微元积分法对海上油田的生产作业具有良好的适用性和应用价值。

用于油井相含率测量的光纤探针传感器研究

针对地面成熟三相流相含率测量传感器无法适应井下高温高压腐蚀的复杂环境,现有井下测量设备复杂,需要多种传感器和探头联合才能实现三相流相含率测量的问题,设计了一种光纤探针传感器。以蓝宝石作为光纤探针的前端敏感材料,利用气相和液相对光的折射率不同,通过检测探针反射光的光强来分辨光纤探针处于气相还是液相。通过检测经探针耦合进光纤的荧光光强分辨水相还是油相,从而实现单一探针传感器对油井内油相、水相、气相三相相含率的测量。

旋转填充床运行过程重要参数预警调控模型

旋转填充床是实现超重力技术的典型过程强化设备。物料黏附丝网填料会导致转子质量不平衡振动,严重影响设备传质效率和长周期运行,而控制化学反应工艺参数变化可以延缓黏附和减小振动。提出旋转填充床运行过程重要参数调控模型构建方法,通过计算流体动力学模拟,基于正交试验分析多参数变化对目标参数影响的趋势规律,获取影响效应程度排序,并确定构建影响预测模型的关键参数。通过Matlab数据拟合,构建旋转填充床运行过程重要参数预警调控模型。以旋转填充床填料持液量和气相压降两个目标参数为例,计算多参数对两目标参数的影响效应程度,拟合建立基于关键参数耦合的持液量和气相压降预警调控模型,揭示多参数变化对两目标参数的影响规律。计算预警调控误差概率,提出旋转填充床运行过程重要参数预警调控模型构建方法。所得成果的应用将有助于监测预警重要工艺参数,在发现设备异常时及时采取有效调控措施,降低振动效应和物料泄漏概率。

吉林油田CO_(2)驱高气液比油井井筒压降预测模型

目前,吉林油田CCUS已进入工业化推广应用阶段,部分井油压超过掺输压力,需介入控压措施,而准确预测井筒压力则是进行转喷预测和控压工艺设计的关键。CO_(2)驱高气液比油井井筒流动具有多组分、存在相变及流型转变等特征,导致现有压降模型不适用。为了进一步揭示CO_(2)驱油井井筒多相流动规律,准确预测井筒压降,开展了油气水三相井筒可视化流动模拟试验,明确了高气液比条件下,气体扰动对油水相间作用的影响规律;基于试验数据,通过因素分析,明确了表观气、液流速和含水率与持液率的变化关系,引入新的无因次数准数,拟合得到持液率计算新模型;综合考虑CO_(2)在原油和水中的溶解度,以及CO_(2)沿井筒流动的相态变化,建立了CO_(2)驱高气液比油井压降预测模型;现场实际测压数据验证表明:新模型最大误差为8.32%。与常用工程压降模型相比,新模型精度最高。该研究成果对保障CO_(2)驱高气液比油井的安全稳定生产具有重要的意义。

油气多相流磁共振在线检测方法及装置

针对目前油气田现场广泛采用的多相流分离检测技术存在的效率低、精度差、数据延迟等问题,研究基于磁共振技术的多相流在线检测方法,形成硬件装置,并开展室内实验及现场应用。提出“静止状态测相含率+流动状态测流速”的多相流磁共振流量测量方法;提出采用先计量油水比再计量含气率的方法实现油、气、水三相相含率的测量。在装置研制方面,提出可应用于流动流体测量的分段式磁体结构和双天线结构,研发了高集成磁共振谱仪系统及配套智能化软件。室内实验及现场应用表明,研制的多相流磁共振在线检测系统存在以下优势:只依靠磁共振技术同时完成流量和相含率检测;在线原位高频率检测,实时监测油井瞬态产液波动;能实现油、气、水三相全量程高精度检测,且不受矿化度、乳化状态影响;绿色、安全、低能耗。

气液固三相循环流化床中气固相含率轴径向的分布

对气液固三相循环流化床中气固相含率沿轴径向的分布进行了实验研究和模拟。实验结果表明：与膨胀床相比，三相循环流化床内的相间接触较为充分；固含率轴向分布的一维沉降－扩散模型模拟值与实验值吻合较好。

气-液-固三相循环流化床局部相含率分布

应用自行开发的微电导探针测试技术,以玻璃珠(dp=0·48mm,ρs=2460kg·m-3)和苯乙烯颗粒(dp=1·45mm,ρs=1264kg·m-3)为固相,空气为气相,水及0·05%、0·20%(质量)SCMC(羧甲基纤维素钠)水溶液为液相,对三相循环流化床(TCFB)的各相局部含率进行了同时测定.考察了不同表观液体速度、辅助液体速度、液体黏度及颗粒密度对局部相含率轴径向分布的影响.在不同操作条件下,获得了1286套局部相含率实验数据.给出了局部固含率和局部气含率与操作条件、流体物性及床层轴径向位置的关联式,关联式的计算值与实验值吻合较好.

内循环三相生物流化床反应器的相含率及氧传递特性研究

通过内循环三相生物流化床反应器（ＩＴＦＢ）的清水试验，对其相含率及氧的传递特性进行了研究。结果表明：ＩＴＦＢ与传统三相生物流化床相比具有不同的氧传递条件，当供气量较小时，内筒传质系数Ｋ_（Ｌａ１）大于外筒的传质系数Ｋ_（Ｌａ２），而当供气量较大时，则Ｋ_（Ｌａ２）＞Ｋ_（ｔａ１）．在本试验条件下，当载体投加量大于１．６ｋｇ时，Ｋ_（Ｌａ）随Ｃ_ｓ的增加而增加。