污水处理流程中离心泵对油滴剪切状况的实测分析

油滴粒径大小是影响旋流器油水分离效率的关键因素之一。通过对油田旋流器污水处理流程中离心泵入口和出口油滴粒径的测定 ,认为离心泵对大于 1 50 μm的原油油滴的剪切率约为 81 % ,对小于 1 50μm的原油油滴的剪切率约为 57%。     

除油旋流器入口流量与基本性能的关系研究

对除油旋流器边壁的油滴粒径变化、旋流器的分离效率以及压力降与入口流量之间的关系进行了研究。结果表明 ,当入口流量达到一定程度时 ,旋流器边壁的平均粒径随入口流量的增加而降低 ,分离效率随入口流量的增加而增加。整个旋流器以及旋流器各段的压力降均与入口流量成指数关系 ,都随入口流量的增加而增加。在旋流器的压力损失中 ,进口、旋流腔及大锥段所占比例最大 ,且基本不随入口流量的变化而变化 ;小锥段次之 ,并随入口流量的增大而增大 ;直管段的压力损失所占的比例最小 ,它随入口流量的增大而不断降低。     

注气对油水分离水力旋流器流场影响模拟分析

采用雷诺应力湍流模型、混合模型和离散相模型对注气型油水分离水力旋流器进行数值模拟,得到其内部流场的速度分布和油滴粒子运动轨迹,分析对比了注气前后进口流量、分流比和充气量对分离效率的影响,数值计算结果与文献实验值进行了比较。结果表明,充气后流场速度增加,油滴粒子逃逸时间缩短,旋流器分离效率提高5%~10%,在一定条件下气浮对旋流分离起到强化作用。     

充气水力旋流器用于油水分离的试验研究

研究了充气量、进料量、分流比以及底流出口压力等主要操作参数对充气水力旋流器分离效率影响的规律 ,得出了较好的工况点 ;与相同结构参数的未充气旋流器的分离性能进行了对比 ,结果表明 ,充气旋流器能明显改善油水分离条件 ,具有较宽的操作弹性和较高的分离效率 ;同时用库尔特粒径分析仪分别测定了它们进口和底流口油滴的粒径分布 ,发现在旋流器中充入空气 ,强化了气浮 ,能够进一步分离更细粒径的油滴。     

T型管内油水分离特性的CFD-PBM数值模拟

目前关于T型管内油水分离特性的数值模拟大多采用Euler-Euler多相流模型,考虑管内油滴粒径分布及其对油水分离特性影响的研究工作尚未见报道。对T型管内的油水两相流动情况和分离特性进行了CFD-PBM数值模拟,并进行了室内实验以验证模拟结果的准确性。结果表明,T型管内油滴粒径随流体流动方向具有逐渐增大的趋势;增大来液中的油滴粒径分布可以有效提高油水分离效率,反之当来液中的油滴粒径较小时,油水两相在T型管内不易分离,相分配比始终与分流比几乎相同;分流比、Reynolds数等操作条件对油水分离效率的影响程度与油滴粒径密切相关,应慎重选取适当的操作条件以保证T型管的油水分离效率。     

T型管内油水分离特性的CFD-PBM数值模拟

目前关于T型管内油水分离特性的数值模拟大多采用Euler-Euler多相流模型,考虑管内油滴粒径分布及其对油水分离特性影响的研究工作尚未见报道。对T型管内的油水两相流动情况和分离特性进行了CFD-PBM数值模拟,并进行了室内实验以验证模拟结果的准确性。结果表明,T型管内油滴粒径随流体流动方向具有逐渐增大的趋势;增大来液中的油滴粒径分布可以有效提高油水分离效率,反之当来液中的油滴粒径较小时,油水两相在T型管内不易分离,相分配比始终与分流比几乎相同;分流比、Reynolds数等操作条件对油水分离效率的影响程度与油滴粒径密切相关,应慎重选取适当的操作条件以保证T型管的油水分离效率。     

聚结破碎模型在水力旋流器模拟中的应用与对比

为研究不同聚结破碎模型对油水分离水力旋流器内油滴粒径分布特性的影响,以双锥式水力旋流器为研究对象,采用计算流体动力学方法加载群体平衡模型,开展12种不同聚结破碎模型组合方案的数值模拟研究。通过开展室内分离性能及粒度分析实验对不同方案模拟结果进行筛选及验证。结果表明:luo聚结与luo破碎组合模拟得出的旋流器底流口油滴粒径体积分数最高在320μm处,占比为45%,与实验结果最接近,说明采用luo-luo组合模型模拟旋流器内油滴的聚结破碎特性较准确。旋流器内油滴粒径值由轴心到边壁呈环形对称的减小趋势,而湍动能变化呈环形对称的增大趋势;不同操作参数条件下luo-luo组合方案的质量效率模拟结果与实验值呈现出较好的一致性,均随入口处理量与溢流分流比的增大先升高后降低,且在处理量为5.23 m~3/h,分流比为30%时,质量效率达到最大值94.6%。     

超重力水力聚结分离器流场分析与性能评估

采用离散相模型以脱油型水力旋流器为研究对象,分析了不同粒径油滴粒子在旋流场内的运移轨迹,得出随着粒径的增大旋流器的粒级效率逐渐升高。基于油滴运移轨迹设计了一种水力聚结旋流分离装置,可在旋流分离前端通过水力聚结使小颗粒油滴聚并成大颗粒油滴,进而增强旋流分离性能。开展室内试验对水力聚结分离器的分离性能和适用性进行验证。结果表明:粒径在100～900μm范围内随着油滴粒径的逐渐增大,旋流分离效率逐渐升高;水力聚结器可在油滴进入旋流分离器前使油滴碰撞聚结致使离散相油滴粒径分布增大,从而提高旋流器分离效率,其最佳入口进液量在4. 12m~3/h左右,最佳分流比为20%。     

重力式油水分离器内聚结构件分离性能的实验与模拟研究

为考察聚结构件对重力式油水分离器分离性能的影响,在理论分析的基础上,对错搭波纹板进行实验与模拟研究,并从油滴粒径在波纹板前后的变化、分离器分离效率、波纹板内流场和油滴浓度分布等方面进行对比研究。实验结果表明,板高较小时,水相出口处大油滴所占份额较低,油水分离效率较好,但会增加波纹板填料堵塞的风险;在波纹板上开孔能有效提高油水分离效果,缩短油滴停留时间;进口流量越大,分离效果越差。采用RNG k-ε湍流模型与离散相模型对错搭波纹板进行数值模拟研究,结果表明,小孔可促进板内流场分布均匀,并为板间质量交换提供通道,使聚结之后的大油滴通过小孔浮升到上层波纹板,缩短油滴浮升距离;开孔波纹板后油滴浓度分布区域集中,具有较好的分离效果。     

断续流对旋流器油水分离效率影响的实验研究

目前,大部分井下油水分离的旋流器由地面游梁式抽油机通过抽油杆柱提供能量,这样进入旋流器流量产生断续现象。通过实验证明断续流流量的不连续性使旋流器油水分离效率下降5％以内,存在一定负影响;溢流含油浓度越高,断续流对旋流分离效率的负影响也越大,所以井下油水分离过程中,不能偏面追求过高的溢流口含油浓度,提高分流比F与入口含油浓度C_i比值,减小断续流对分离效率的影响。     

Mathematical modelling of a hydrocyclone for the down-hole oil–water separation (DOWS)

In this study, a mathematical model is developed to predict the efficiency of a down-hole oil–water separation hydrocyclone. In the proposed model, the separation efficiency is determined based on droplet trajectory of a single oil droplet through the continuous-phase. The droplet trajectory model is developed using a Lagrangian approach in which single droplets are traced in the continuous-phase. The droplet trajectory model uses the swirling flow of the continuous-phase to trace the oil droplets. By applying the droplet trajectory, a trial and error approach is used to determine the size of the oil droplet that reaches the reverse flow region, where they can be separated. The required input for the proposed model is hydrocyclone geometry, fluid properties, inlet droplet size distribution and operational conditions at the down hole. The model is capable of predicting the hydrocyclone hydrodynamic flow field, namely, the axial, tangential and radial velocity distributions of the continuous-phase. The model was then applied for some case studies from the field tested DOWS systems which exist in the literature. The results show that the proposed model can predict well the split ratio and separation efficiency of the hydrocyclone. Moreover, the results of the proposed model can be used as a preliminary evaluation for installing a down-hole oil–water separation hydrocyclone system in a producing well.     

The influence of design and operating variables on energy consumption and separation efficiency of a hydrocyclonic concentrator

The problem of physical separation of solids from liquids in very dilute concentrations by hydrocyclone concentration is considered in two parts. First, the effect of feed concentration, volume split, feed flowrate, cone angle, inlet diameter and vortex finder length on separation efficiency and energy loss are investigated. The relationship between the separation efficiency; and the energy loss is also studied. Secondly, the effect of three different designs of body shape on the separation efficiency and energy loss is investigated. In this study statistical concepts are used extensively in the design of experiments and the analysis of experimental results.     

含聚浓度对旋流器性能影响的数值模拟与试验

以螺旋导流式旋流器为研究对象,选用幂律流体模型和离散相模型（DPM）计算了不同含聚浓度条件下的分离性能,对旋流器流场（速度场、压力场）及油滴运移特性进行了细致的分析,并采用高速摄像技术（HSV）开展了相应的分离特性试验。研究发现：聚合物浓度为0时,油滴存在明显的乳化效应,实测效率81.7%;浓度增大后,乳化效应减弱,油滴分散在旋流器内,中心油核消失,效率急剧下降,4000mg/L时旋流器基本无分离效果;浓度增大对压降影响较小,底流压降最高增幅5.6%,最大值不超过200kPa。分析表明,效率下降与切向速度衰减、径向压力梯度减小有关;浓度增大后油滴轴向向下运动的距离增加,呈现向旋流器外壁面运动的趋势,分离时间延长。     

Pressure drop and separation efficiency in a flooded hydrocyclone

The pressure drop and separation efficiency were measured of a hydrocyclone operating under flooded underflow or no air-core conditions. The solids were glass spheres with a geometric number average diameter of 13 μm and a geometric standard deviation of 1.69. Water was the fluid. Other fixed variables included the solids feed concentration of 2265 mg/L, the glass hydrocarbon configuration following the optimal Rietema recommendations and the temperature. The variables were feed flowrate 0.44 to 0.63 L.s¹ and volume split of 2.4:1 to 6.1:1; a factorial design was used. The pressure drop, ΔP_s, was 4 to 7 times larger than that expected for air core operation and was correlated in terms of the capacity ratio Q/(ΔP_s)^0.47. The pressure drop was relatively independent of volume split. The separation efficiency was a much stronger function of volume split than of feed flowrate. The D_p(50) diameter at a feed flowrate of 0.63 L.s⁻¹ lies between 4.3 to 9.2 μm; of the seven correlations available for predicting D_p(50), the approach of Rietema (1961) gives the best results. The experimentally measured reduced efficiency was less sharp than that reported by Yoshioka and Hotta (1955) and by the theory of Uematu et al. (1962).     

Developing a new approach for evaluating a de-oiling hydrocyclone efficiency

In this study, a new mathematical approach for evaluating of a de-oiling hydrocyclone efficiency has been developed. This new model uses the flow pattern of disperse phase and the boundary layer separation theory. In the present model unlike the other existing models, it is assumed that the droplet concentration in the radial direction is not uniform within the hydrocyclone. The hydrocyclone separation efficiency is calculated considering the droplet size distribution of the feed and the boundary layer thickness. The present approach considers the effects of droplet load, hydrocyclone geometry, mean droplet size and flow rate on the efficiency. The model is validated by comparison of the calculated separation efficiency with several previous experimental studies.     

旋流气浮中气泡-颗粒碰撞效率影响因素理论分析

在旋流气浮接触区碰撞模型基础上,通过理论计算考察了物性、运行和结构参数对分散相颗粒/油滴与气泡碰撞效率的影响. 结果表明,物性参数中的分散相粒径与密度、运行参数中气泡直径与切向速度和结构参数中等效旋流直径对碰撞效率影响较大. 在旋流气浮工艺中,碰撞效率随分散相粒径增大而增大,但随气泡直径和分散相颗粒/油滴密度增大而减小;分散相粒径小于0.02 mm时,碰撞效率随切向速度增大而减小、随等效旋流直径增大而增大;分散相颗粒/油滴大于0.02 mm时,碰撞效率随切向速度增大而增大、随等效旋流直径增大而减小. 旋流气浮去除的主要是油滴大于0.02 mm的非溶解性油,因此,设备紧凑可提高气泡与分散相颗粒的碰撞效率,达到高效分离目的.     

油井采出液预分水用轴向水力旋流器的实验研究

高含水油井采出液的高效预分水是目前油气集输处理领域面临的关键难题之一,轴向水力旋流器因具有结构紧凑、分离效率高等优点而得到了国内外的广泛关注。本文针对自主研发的油井采出液预分水用轴向水力旋流器开展了室内实验研究。与切向水力旋流器对比,轴向水力旋流器不仅分离效率更高,而且油出口处的油滴聚结长大近1.8倍,在分水率高于50%的情况下,水出口处的含油浓度低于1000mg/L;轴向水力旋流器压降较低,且压降比与分流比呈线性相关。分流比、含水率和流量对分离性能均有显著影响,其中分流比的变化直接影响油核的大小和稳定性,室内样机的最佳分流比为0.45,当含水率为90%、处理量为1.00m³/h时分水率与含油浓度分别为62.9%和432.8mg/L;含水率高于75%时分离性能良好;室内样机的最佳流量为1.50m³/h。自主研发的轴向水力旋流器不仅满足性能要求,而且在操作弹性、可控性方面较切向水力旋流器均有一定的提升。