某磷矿浮选柱用气泡发生器的研究与改进

气泡发生器是浮选柱的重要部件,它的结构直接左右其使用寿命、成本以及浮选柱内气泡的尺寸和分布,对浮选柱的分选效果有重要影响.介绍浮选柱原理及气泡发生器的结构.针对使用过程中存在的问题对气泡发生器进行一系列改进,稳定了分选效果,降低了运营成本.     

浮选柱气泡发生器的研究与进展

介绍了浮选柱气泡发生器的研究与发展;论述了几种发泡方式及其优缺点;分析了各种内置发泡器和外置发泡器的结构类型和工作原理,比较了各种发泡器的优缺点及气泡尺寸情况。     

微泡旋流浮选柱在中梁山选煤厂的应用

简述了微泡旋流浮选柱的工作原理；归纳了浮选柱的操作要点。与ＸＪＭ－４型浮选机的生产技术指标对比表明，微泡旋流浮选柱适用于细粒煤泥浮选。     

浮选柱在磷矿扫选中的工业化应用

把浮选柱应用到磷矿选矿中,且利用先进的浮选柱对一次选矿中的细粒尾矿开展深度加工,使丢弃的尾矿中的磷资源得到充分回收,与原有全槽式浮选机组装置相比较,尾矿中的P2O5含量至少降低了2%,提高磷收率,增加了经济效益。     

FCMC旋流微泡浮选柱的研制与开发

ＦＣＭＣ旋流微泡浮选柱是一种新型高效的细粒分选设备。本文重点介绍其原理、结构及在选煤领域的开发应用,阐述其在选矿行业的广泛应用前景。     

西南某磷矿柱式正反浮选工艺研究

采用实验室型旋流-静态微泡浮选柱对我国西南地区某难选硅-钙质胶磷矿进行了柱式正反浮选工艺研究.以XM-10作为正浮捕收剂,水玻璃作为硅酸盐矿物抑制剂和矿浆分散剂,以硫磷混酸作为磷矿物抑制剂,PA-64作为碳酸盐矿物捕收剂,考察了磨矿细度、药剂用量等因素对浮选指标的影响.结果表明,采用旋流-静态微泡浮选柱正反浮选工艺可以得到精矿P2O5品位29.92%、MgO质量分数0.73%、磷回收率85.97%的浮选指标,简化了胶磷矿浮选工艺流程.     

充填式浮选柱的研究与应用

简要介绍了充填式浮选柱的发展历程及其特点 ,综述了近年来国内外学者对该设备的内部结构、流体力学特性、数学模型等基础理论的研究状况 ,以及充填式浮选柱在金属矿、煤、非金属矿等分选工艺中的主要应用情况 ,指出了目前所存在的一些有待解决的问题 ,并从基础理论和实际应用两个方面提出了几个有待进一步深入研究的课题和发展方向     

充填静态浮选柱在胶磷矿浮选中的应用

考察了在充填式静态浮选柱中浮选低品位胶磷矿时,药剂用量、洗涤水加入位置及用量及各种操作因素对浮选结果的影响,得到了合适的浮选条件,为工业放大提供了依据。     

充填浮选柱正-反浮选胶磷矿工艺研究

通过充填浮选柱浮选胶磷矿的工艺实验,提出了串联操作的正一反浮选流程,得到了较为合适的工艺条件,为生产放大提供了理论依据。     

旋流器操作和浮选性能影响因素的研究

设计并构建了气泡发生器、旋流浮选器的结构以及旋流浮选的流程.浮选性能包括两个方面:分离效率和气浮浓缩倍数.得出了压力降与处理量之间的关系;压降比与底流分率的关系;处理量与分离效率和气浮浓缩倍数的关系;底流分率与分离效率和气浮浓缩倍数的关系.     

PREDICTION OF GAS-PHASE HOLDUP IN A BUBBLE COLUMN

Hydrodynamic properties of bubble columns play a significant role in many chemical and biochemical processes. Recent theoretical and experimental work conducted by Krishna et al. (1991, 1994), and Wilkinson et al. (1992) have been examined in conjunction with a bubble column and data for the air-water system operating at ambient conditions. The bubble column is 0.108 m in internal diameter, has a 1.70 m tall test section, and is equipped with a perforated plate distributor having 91 holes of 0.8 mm diameter. The data are taken for five values of the slumped water column height in range from 0.79 to 1.15 m, and for superficial air velocities up to about 0.4 m/s.

The data accord to the qualitative aspects of Krishna et al. model but lead to different values of the bubble swarm rise velocity, and superficial transition air velocity characterizing the transition from homogeneous bubbly flow regime to heterogeneous churn-turbulent flow regime. The quantitative reproduction by the model expressions of these recent works of the experimental data is poor. This may be partly attributed to the geometry of the column, diameter and distributor design.

The qualitative features of Krishna et al. model for the two regimes are confirmed by the present data. For quantitative predictions of gas-phase holdup, a new model is proposed in which the large bubble flow in the churn-turbulent regime is formulated following the drift-flux theory. The proposed theory and experimental data are in good agreement.     

鼓泡塔结晶器中的晶层生长

结合未充分发展弹状流的传递特征和晶层内不稳定导热 ,提出了鼓泡塔结晶器管内晶层生长的时间级联模型 ,与实验值吻合良好 .特定操作条件下 ,随弹状泡的到来和离去 ,结晶界面可发生结晶 -部分重熔 .     

EFFECTS OF TURBULENT SHEAR STRESS ON THE GROWTH OF SUSPENDED PLANT CELLS IN A BUBBLE COLUMN REACTOR

In this paper,effects of increasing the height of column,bubble size and gas flow rate onthe growth of suspended Catharanthus roseus plant cells in a 1.5 litre bubble column were studied.Statistical characteristics of turbulence such as auto-correlation function,and auto-power spectral den-sity function of the nuctuating liquid velocity were measured in a bubble column employing pseudo-cell-granulated agar.Calculations of turbulent shear stress were carried out.From these studies it is sug-gested that in plant cell suspension culture sparged with large bubbles.turbulent shear stress is prob-ably one of the most important reasons for the inhibited cell growth and cell damage.Larger bubblesor higher gas flow rates lead to the increase in shear stress and are more detrimental to plant cells.     

操作变量对大型浆态床反应器流体力学特性的影响

研究了系统压力、表观气速和固体颗粒体积分数对浆态床反应器气含率、气泡直径及气液接触面积的影响 ,通过试验得出了气含率和操作变量之间的统计关联式 ,给出了在湍流条件下浆态床反应器中气含率和气体动量之间的关系     

热态下鼓泡浆液反应器的气含率研究

本文在热态条件下，研究了鼓泡浆液反应器的气含率、反应器直径为0.098m，物系组成为氮气－液体石腊－石英砂。考察了气速、压力、温度、静床高及固体引入等因素对气含率的影响。对于53μm粒子的三相浆态体系，气含率与表观气速关系式为εG=0.053uG^1.2。     

GAS-LIQUID MASS TRANSFER IN JET BUBBLE COLUMN

The jet bubble column consists of a conical entrance section which expands to a cylindrical column. Gas and liquid are co-currently introduced at the bottom of the column by a small diameter inlet pipe which acts like an ejector. The kinetic energy of the gas and liquid jet together with the conical geometry at the lower section of the column cause the formation and dispersion of small bubbles.

Gas-liquid mass transfer in the jet bubble column (61 cm diameter) was measured by a dynamic response technique, in which a step change was made in the gas phase oxygen concentration and the aqueous dissolved oxygen concentration response was measured at various axial and radial locations. It was found that a continuous stirred tank reactor model could be used to evaluate experimental results. The volumetric mass transfer coefficient in this type of system was found to increase with increasing gas flow rate and was about 1.5 times larger than the values obtained at similar conditions in conventional bubble columns. Preliminary measurements and calculations indicate negligible effects of liquid velocity and bed height on the mass transfer coefficient.     

鼓泡床内气泡-液体两相湍流代数应力模型的数值模拟

现有的气泡 -液体两相流动的数值模拟中 ,或者不考虑湍流 ,或者仅仅考虑液体湍流 ,但是直接模拟和PIV测量结果都表明气泡由于尾迹的作用有强烈的湍流脉动 .本文首次推导和封闭了同时模拟气泡湍流脉动和液体湍流脉动的二阶矩输运方程两相湍流模型 ,并在此基础上建立了代数应力气泡 -液体两相湍流模型 .用代数应力模型模拟了二维矩形断面鼓泡床内气泡 -液体两相流动 .预报结果给出了气泡和液体两相速度场、两相Reynolds应力及湍动能分布和气泡体积分数分布 .模拟结果与PIV测量结果符合很好 ,表明了模型的合理性 .研究结果表明 ,原先静止的液体在气泡因浮力而产生的上升运动的作用下产生回流流动 ,而气泡则只有上升运动 .气泡速度始终大于液体速度 .在床内气泡湍流脉动确实始终很强烈 .液体则由于气泡的作用以及自身速度梯度产生的双重作用而发生湍流脉动 .气泡的脉动显著地大于液体的脉动 .两相湍流脉动都是各向异性的 ,而且气泡湍流脉动的各向异性比液体的更强烈     

HYDRODYNAMICS, MIXING AND MASS TRANSFER IN A LARGE DIAMETER JET BUBBLE COLUMN

Experimental measurements for the axial and radial variations in gas holdup, axial and radial dispersion coefficients, volumetric gas-liquid mass transfer coefficient and liquid phase circulation velocity in a cone of a large diameter (122 cm) jet bubble column are presented. Two diameters of the inlet nozzle, namely 10.16 cm and 15.24 cm, three superficial gas velocities (based on cylinder diameter), 3 cm/sec, 6 cm/sec and 8 cm/sec and two superficial liquid velocities, 0.3 cm/sec and 0.6 cm/sec, are examined. The experimental data are obtained for two different bed heights.

The experimental data showed significant axial and radial variations in the gas holdup. The volumetric average gas holdup was higher at higher gas velocity and larger nozzle diameter and somewhat higher at lower liquid velocity. The axial dispersion was high while the radial dispersion was low. The volumetric gas-liquid mass transfer coefficient was larger at higher gas velocity and larger nozzle diameter. The liquid recirculation begins only at the upper end of the cone. In general, experimental data indicate that a jet bubble column provides a high degree of mixing and transport rates.     

PREDICTION OF ENERGY DISSIPATION IN A CONVERGENT-DIVERGENT MULTISTAGE BUBBLE COLUMN

An experimental investigation was carried out to evaluate energy dissipation of a divergent-convergent multistage bubble column (with convergent and divergent disks), which has been conceived, designed, and fabricated as a wet scrubber for air pollution control. In addition it has versatile use as a gas-liquid contactor in chemical and biochemical process industries. A detailed experimental investigation of pressure drop and energy dissipation has been reported by using a divergent-convergent multistage bubble column. Correlation developed for predicting energy dissipation has been found to be encouraging and highly significant from a statistical point of view. Energy consumption of the present system has been compared with other systems.     

PHASE DISTRIBUTION AND MIXING IN A JET BUBBLE COLUMN

This paper describes the results of an experimental study to evaluate phase holdups and RTD for a jet bubble column. The experimental data were obtained in a 61 cm diameter jet bubble column with a conical inlet. Air and water were used as a two-phase system. The ranges of gas and liquid velocities examined were 0 to 9 cm/sec and 0 to 0·6 cm/sec respectively, both based on the cylinder diameter. The experimental data indicate that in the conical section of the column, the gas holdup first decreases with an increase in distance away from the cone inlet, achieves a minimum and then increases until it reaches a somewhat constant value within the cylinder. Gas holdup varies radially with the maximum at the center and the minimum near the wall. Radially-averaged gas holdup increased with gas velocity and remained essentially unchanged with liquid velocity. The RTD measurements were correlated by a two-dimensional dispersion model. The axial dispersion coefficient increased linearly from the cone inlet to the cylinder. It also increased with the gas velocity. The radial dispersion coefficients were considerably smaller than the axial dispersion coefficients.