低温甲醇洗热再生系统存在的问题及改进措施

针对低温甲醇洗装置克劳斯气夹带甲醇及系统甲醇中油含量高的问题,分析其原因并提出改进措施.对克劳斯气分离器降液管改造后,消除了克劳斯气夹带甲醇的现象,降低了系统甲醇中的油含量,取得了较好的经济效益.     

酸性气体脱除装置尾气冷量回收优化改造

某合成氨厂对酸性气体脱除装置再吸收塔下塔塔盘进行整体更换改造，将浮阀塔盘改为固阀塔盘，虽然解决了高负荷生产时下塔液泛、酸性气甲醇夹带量大等问题，但同时也产生了尾气排放量变大、排放温度远低于设计值等新问题。结合装置运行参数对工艺流程重新进行模拟计算，提出新增尾气/贫甲醇换热器的改造措施，充分回收尾气冷量，降低装置能耗。     

低温甲醇洗装置洗涤甲醇消耗偏高的原因及对策

介绍了低温甲醇洗装置在试车过程中存在的问题,分析了装置中洗涤甲醇消耗偏高的原因,提出解决问题的办法。系统调整及技术改造后,降低了装置排放气体中的甲醇夹带量,合成气和酸气中的甲醇夹带量也明显减少,效果显著。     

低温甲醇洗CO2产品气中夹带甲醇的问题及改造

介绍了中煤图克合成氨/尿素装置配套的低温甲醇洗CO_2吸收及再生系统工艺流程,分析了生产运行过程中CO_2产品气中甲醇含量高的问题。通过在CO_2产品气管道上增设高效除沫器的方法,将其中夹带的甲醇回收再利用,从而将CO_2产品气中夹带的甲醇体积分数降至300×10~(-6)以下,保证了系统正常稳定运行,且降低了生产运行成本,年可节省甲醇费用约300万元。     

环状流液滴夹带率测量方法及分析

针对气液两相环状流液膜参数溯源问题,设计了一种液膜在线提取装置和基于液膜质量流量测量的夹带率测量方法。该装置利用超声波测距传感器对储液箱液位进行实时监测并反馈至控制系统,利用单片机控制抽气泵开关实现对环状流多孔渗水介质管段内外差压调节控制液膜析出速率,使用换向器实现计量和废液管路切换并记录两次切换之间的时间间隔。利用精密电子天平对取出液膜进行称重测量,结合记录时间和液相质量流量计测量结果实现液膜质量流量和液滴夹带率等参数的测量。在小口径高精度气液两相流模拟装置进行了75组实流验证实验,并结合两种典型夹带率模型预测结果对测量系统进行了科学评价。研究结果表明,液膜质量流量和液滴夹带率测量结果可溯源,测量准确度高,为研究气液两相环状流液膜流动特性提供了一种可靠的实验测试方法。     

闪蒸气中碳酸丙烯酯带液超标的原因及处理

分析脱碳系统开车初期３次碳酸丙烯酯跑液事故和闪蒸气中碳酸丙烯酸气液夹带超标的原因。从解决闪蒸气中因气液夹带引起跑液着手对原流程作了有效改进，从而杜绝了闪蒸气中大量碳酸丙烯酯气液夹带引起跑液事故发生的可能性。     

双氧水装置氧化液泵气缚现象浅析

广西柳州化工控股有限公司固定床工艺双氧水装置多次发生氧化液泵气缚现象,经分析主要原因是工作液的组分发生了改变(杂质含量过多),氧化液表面张力减小,造成夹带的空气增多,气液分离困难,来不及分离的气泡进入氧化液泵泵体内而致.为找到解决氧化液泵气缚问题的办法,据生产经验和现场观察,重点分析了(正常生产情况下)氧化液贮槽中氧化...     

上海科技信息

▲甲醇精馏残液汽化燃烧处理技术上海吴泾化工总厂年产10万吨甲醇装置每小时产生甲醇残液约6.5～8吨,其中甲醇含量5000～10000毫克/升,化学耗氧量6000～120000毫克/升。该厂科技人员根据有关试验,确认甲醇残液采用汽化处理是一项较好的治理技术,决定将部份甲醇残液送造气     

气液过滤过程中液滴二次夹带现象分析

在天然气长距离输送过程中,天然气夹带的液滴严重影响压缩机组的安全可靠运行。利用所建立的滤芯过滤性能检测装置,以癸二酸二辛酯为实验介质,分析了天然气净化用滤芯气液过滤过程中液滴二次夹带现象的特征,比较了滤材润湿性和过滤速度等参数的影响。结果表明:当滤芯仅由聚结层组成时,滤芯过滤过程中存在液滴二次夹带现象,二次夹带将导致下游气体中液滴数量增多,且有较大液滴出现,稳态阶段滤芯累积效率在大粒径处下降;液滴在滤材表面的润湿性对二次夹带现象具有重要影响,可润湿型滤材表面更易出现液滴二次夹带现象,在相同过滤速度下,若需提高过滤效率,宜选用不可润湿型滤材制作工业滤芯;在0.1～0.3 m·s^-1过滤速度范围内,提高过滤速度可减少液滴二次夹带现象的发生,与不可润湿型滤芯相比,可润湿型滤芯过滤效果的改善更为明显;滤芯增加排液层可有效消除液滴二次夹带现象。     

300 kt/a合成氨装置中压氮气及合成弛放气回收利用总结

吉林石化公司化肥厂300 kt/a合成氨装置增设抽氢气、抽合成气装置后,空分单元存在富余中压氮气,从氮压机三段出口引出一股氮气并入化肥厂中压氮气管网回收利用,因2股氮气存在压差,增上减压阀后实现了氮气并网;原设计合成弛放气为过热炉F1301提供燃料气,但由于燃料气降压后出现气液夹带现象,合成弛放气无法正常投用,几经摸索,增设气液分离器后,实现了合成弛放气的回收利用。     

Drop breakup and entrainment in the updraft

This study aims to investigate the characteristics of gas–liquid countercurrent contact processes. In spray towers or other applications, several drops containing pollutants are entrained by the updraft flue gas, which can easily cause environmental pollution. Traditionally, this drop entrainment phenomenon is alleviated by increasing the diameter of the drops. However, the breakup of a large drop would also cause drop entrainment to become serious, a process referred to as secondary atomization. Herein, we propose the boundary of three drop modes in the updraft: drop falling mode, reverse entrainment mode, and breakup entrainment mode. The critical Weber number (We) is the key dimensionless number marking the beginning of the drop breakup. The ratio of the drag force to gravity and We are proposed as criteria for the drop entrainment.     

循环冷却水系统的气液夹带问题分析

节水减排是工业发展的必然趋势和重要组成部分。本文从生产实际出发,在对循环冷却水系统及水源进行介绍的基础上,对气体液滴夹带现象及其机理、影响因素进行了分析,并对新型气液夹带控制技术进行了综述。     

Dispersion of liquid–liquid phase by a jet-induced gas–liquid–liquid mixing column developed for separation of organic pollutants

This article presents the gas and liquid entrainment and its dispersion in a gas–liquid–liquid mixing column. The variations in phase entrainment is observed with the change in the paraffin liquid and kerosene volume fraction from 5% to 35% due to the increase in the flow resistance with increase in the effective viscosity of the liquid–liquid mixture. The degree of dispersion is enunciated based on the axial dispersion model and the flow resistance of the phases in the column. A correlation is proposed to interpret the entrainment of phase as a function of operating variables within the range of experimental conditions.     

基于环雾流理论的气井临界流速预测模型

井筒积液是伴随气井生产的常见现象，积液会导致气井产量降低，严重时甚至会使得气井停产。精确的积液预测有助于及时采取措施以减少积液带来的危害，而临界气体流速是气井积液预测的关键。回顾了气井积液预测的相关研究，指出了最小压降模型、液滴模型的局限性，基于现有实验观察认为液膜模型有较好的适用性。考虑到斜井中液膜周向不均匀分布及气相核心中液滴夹带，提出了更符合实际的环雾流模型用于不同管径、不同井斜角下的气井积液预测。基于以往室内实验数据和现场生产数据，将新模型与现有6种积液预测模型进行对比评价。综合考虑模型预测结果正确率及预测误差，认为新的环雾流模型较其他模型预测结果更优，可准确方便地对气井积液进行预测。     

Void fraction in vertical gas-liquid slug flow: Influence of liquid slug content

In this study we develop a model for computing the mean void fraction and the liquid slug void fraction in vertical upward gas-liquid intermittent flow. A new model for the rate of gas entrained from the Taylor bubble to the liquid slug is formulated. It uses the work done by the pressure force at the rear of the Taylor bubble. Then an iterative approach is employed for equating the gas entrainment flux and the gas flux obtained via conservation equations. Model predictions are compared with experimental data. The developed iterative method is found to provide reasonable quantitative predictions of the entrainment flux and of the void fraction at low and moderate liquid slug void fraction conditions. However, with an increased liquid slug void fraction experimental data indicate that the flow in the liquid slug transits to churn-heterogeneous bubbly flow thus gas entrainment flux tends to zero. Considering this effect in the iterative model significantly improved the predictions for large liquid slug void fraction conditions.     

CFD modeling of gas entrainment in stirred tank systems

In the present work, CFD modeling was used to study the phenomenon of gas entrainment in stirred tank systems. Two types of impellers (DT, PBTD) were simulated. VOF method was used as surface tracking technique along with LES model to study interfacial behavior at the onset of gas entrainment. Simulations were performed to study cause of entrainment and underlying interfacial mechanism at the location of entrainment. CFD simulations clearly showed differences in onset and non onset conditions in terms of the magnitudes of interfacial turbulence. As per the predictions, phenomenon of surface aeration in stirred tank systems was characterized by exchange of momentum across the interface from water side to air side. Magnitudes of instantaneous axial velocities on air side, strain rates on air side and vorticities on air side exhibited a threshold at the onset of entrainment and reduced substantially after the onset.     

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。     

液相性质对新型洗涤冷却室内液滴夹带的影响

采用等速取样法对床层气液鼓泡区上方分离空间的液滴夹带进行了实验测定,研究了液相性质对液滴夹带的影响. 结果表明,同一静态液位下,随气速增加,气液分离空间高度逐渐减小,液滴夹带量增大;出口处液滴夹带量E在径向上总体变化不大,贴近壁面处偏小,主要受气体出口处气体回流流动的影响;液滴夹带量随液相物质表面张力减小而增大,随液体粘度增大而增大,表面张力从72.8 mN/m减小到25.8 mN/m液滴夹带量增大2.5倍,液体粘度从1 mPa×s增加到2.3 mPa×s液滴夹带量增大1倍. 液体物性对液滴夹带量的影响较显著,由此建立了液滴夹带量与物性参数的经验关联式,为改善洗涤冷却室内部结构提供了理论依据.     

Re-entrainment in wave-plate mist eliminators

Wave-plate mist eliminators are among the most effective devices to separate liquid from the gas. Liquid separation efficiency in these devices is largely dependent on the gas superficial velocity. However, the upper limit of gas throughput is restricted by the re-entrainment of the deposited liquid from the separator surfaces into the gas stream. There is some knowledge available of re-entrainment phenomena in vertical wave-plate separators. This paper presents experiments that have enabled the mechanisms of entrainment to be identified and the boundaries for air and liquid rates at which entrainment starts for horizontal wave-plate separators to be characterised. It is supported by modelling using an extension of earlier work.