利用冷凝侧回收热调控供液温度特性分析

针对某型液冷源供液温度波动较大以及冷凝侧热无利用排放问题,通过对系统工作原理和冷凝侧换热器结构等方面进行分析,提出可以利用冷凝侧回收热控制供液温度波动或实现供液温度的精确控制。建立了冷凝侧换热器的计算模型,并计算出系统冷凝侧空气进、出口温度、冷凝温度和冷却液出口温度等工作参数,以及在不同工况下的热回收量。结果表明,通过冷凝侧热回收的方式对液冷源供液温度进行调控,能够抑制供液温度波动,避免压缩机频繁启停,提高液冷源工作稳定性;冷凝侧热回收时,最大冷却液旁通流量为总流量的50%左右最为合适,并总结了系统制冷量与总热负荷能够实现平衡的工况区域。研究结论结果可为相关领域冷凝侧热利用提供参考。     

含硫轻质原油油气回收工艺的优化

为研究我国进口的中东含硫原油油气回收情况,有效去除含硫成分,采用冷凝回收的方法,利用Aspen模拟研究该回收工艺的过程,并对冷凝回收工艺进行优化。研究结果显示:油气回收工艺中冷凝温度对于油气组分的回收率影响最大,冷凝过程运用三段冷凝工艺。三阶段温度分别为2℃、-50℃、-130℃,使油气回收率提高到84%以上。     

空调冷凝热回收系统石蜡基相变材料的初步实验研究

针对目前国内压缩式冷凝机组的冷凝排热显热回收存在的问题,提出了利用相变蓄热材料对空调冷凝热进行储存、回收利用的新思路,利用热回收系统制取卫生热水;对石蜡基蓄热材料及其改性材料降低相变储热温度进行了研究,通过实验研究石蜡基蓄热材料及其改性材料的热物理性质,包括其体积膨胀率、凝固与熔解曲线以及其热稳定性.     

净化冷凝液的环保回收

通过改进开停车方法和增加一套汽提塔来处理合成氨装置净化工段的工艺气冷凝液和二氧化碳冷凝液,确保环保回收及循环使用,达到节能效果。     

一种新型冷凝液回收泵磁力换向机构的设计

蒸汽冷凝后的热水回收工况十分复杂，一般离心式、往复式泵均难以适应这种特殊工况。磁力换向机构是新型冷凝液回收泵（ZL200410016693．X）的关键设备，具备优良的汽蚀性能和流量自调特性，能够可靠、高效地回收冷凝液。     

蒸汽冷凝液的综合利用

工业部门广泛应用蒸汽作发电、加热、烘干、保温、取暖等用途。但大部分企业对“蒸汽”这一能源仅仅使用一次,当蒸汽形成冷凝液后,就作为废物排泄,或把这些具有一定应用价值的能源排向空间。这样既造成大量能源和水源的浪费,又污染了环境。本文就如何充分利用这一潜力很大的能源提出下列看法。一、回收蒸汽冷凝液的用途在凝汽式电站中,蒸汽冷凝液通过处理后,就能直接回到锅炉内使用。但是,在一般工厂中回收的蒸汽冷凝液也可作多次综合利用,我们提出的流程图如下:蒸汽(供生产设备加热用,为一次利用)→处于饱和     

燃气锅炉排烟冷凝热回收分析

通过对天然气烟气特性的分析以及对冷凝式锅炉热效率的分析和计算得出：将烟气温度降低到露点温度以下。对烟气进行余热回收有重要的实际意义。冷凝式换热器就是增设在天然气锅炉尾部的余热回收装置。该装置可以将排烟中大量的能量加以回收利用,从而达到节能环保的效果。对冷凝式换热器进行了热力计算,得到了露点温度,常规段管长和冷凝段管长。实验结果表明：若将烟气温度降低到露点温度以下回收水蒸气释放的汽化潜热,可将锅炉效率提高10％以上,该方法目前已开始在工业生产中进行推广应用。受到较高评价。     

中央空调冷凝热回收技术的应用

中央空调运行时产生大量的冷凝热，可以利用双冷凝嚣进行回收，介绍了制备生活热水的技术方案，并作了经济分析。     

煤油气相干燥设备冷凝回收系统控制方式分析

近年来,煤油气相干燥设备在很多大型变压器企业中均得到认可。煤油气相干燥设备冷凝回收系统的功能对整个控制系统的功能具有十分重要的作用。通过对冷凝回收系统的构成进行分析,本文阐述了冷凝回收系统的工作原理,并结合具体的工作原理分析了煤油气相干燥设备冷凝回收的两种工作方式。     

中央空调冷凝热回收技术的应用

中央空调是使用较多的空调,其在制冷工作时,很多热量都流失浪费掉。空调冷凝热回收技术是针对这样的技术进行运用,实现热量利用。文章主要对中央空调冷凝热回收技术进行探讨,分析该项技术的实践应用,对当前环保、节能所具有的优势进行阐释。     

An analytic study on laminar film condensation along the interior surface of a cave-shaped cavity of a flat plate heat pipe

An analytic approach has been employed to study condensate film thickness distribution inside cave-shaped cavity of a flat plate heat pipe. The results indicate that the condensate film thickness largely depends on mass flow rate and local velocity of condensate. The increasing rate of condensate film for circular region reveals about 50% higher value than that of vertical region. The physical properties of working fluid affect significantly the condensate film thickness, such as the condensate film thickness for the case of FC-40 are 5 times larger than that of water. In comparison with condensation on a vertical wall, the average heat transfer coefficient in the cave-shaped cavity presented 10-15% lower values due to the fact that the average film thickness formed inside the cave-shaped cavity was larger than that of the vertical wall with an equivalent flow length. A correlation formula which is based on the condensate film analysis for the cave-shaped cavity to predict average heat transfer coefficient is presented. Also, the critical minimum fill charge ratio of working fluid based on condensate film analysis has been predicted, and the minimum fill charge ratios for FC-40 and water are about Ψ_crit= 3-7%, Ψ_crit=0.5-1.3%, respectively, in the range of heat fluxq” = 5-90kW/²     

An analytical investigation into the Nusselt number and entropy generation rate of film condensation on a horizontal plate

This study investigates the heat transfer characteristics and entropy generation rate of a condensate film formed on a horizontal plate with suction at the wall. Applying the minimum mechanical energy principle, the dimensionless liquid film thickness along the plate is found to vary as a function of the Rayleigh number, the Jakob number, the Prandtl number and the suction parameter. The governing differential equation of the condensate thickness is solved numerically by using a finite-difference shooting method. Closed-form analytical expressions are derived for the Nusselt number and the dimensionless overall entropy generation number. When there is no suction at the wall, the results obtained from the analytical expression for the Nusselt number are found to be in good agreement with those presented in the literature. This paper was recommended for publication in revised form by Associate Editor Dae Hee Lee Tong-Bou Chang received the Ph.D. degree in Mechanical En-gineering from National Cheng Kung University, Tainan, Taiwan, in 1997. From 1997 to 2001, he was a researcher at Yuloon-Motor Group (Taiwan), whose job function includes design and characterization of the thermal and fluid flow systems for vehicle. Since 2002, he has been as a Professor at the Department of Mechanical Engineering, Southern Taiwan University. His current research interests include heat transfer with phase change, energy-system optimization, heat and mass transfer in porous medium, enhancement heat transfer and high performance heat exchangers.     

乙烯装置蒸汽凝液工艺优化改造

中国石油兰州石化分公司460 kt/a乙烯装置为实现节能降耗,对蒸汽凝液工艺流程进行了2次优化改造,合理回收了蒸汽凝液的余热,用于加热脱盐水,降低了乙烯装置低压蒸汽用量,优化了操作条件,实现了装置节能降耗,使装置的低压蒸汽用量减少了16.5 t/h左右,降低装置综合能耗约18 kgEo/t。     

等效焓降法在烟气余热换热器节能中的应用

等效焓降法是基于热力学的热功转换原理。本文用等效焓降的方法分析了热力系统加装烟气换热器的节能效果。论证了锅炉余热的热经济性效果,并以600MW机组为例,对凝结水返回系统不同位置的四种方案进行了比较。最后通过定量计算得出加装烟气余热换热器对热力系统节能的重要作用。对工程实践有重要的指导意义。     

Energy metering system for high quality saturated steam

For accurate measurement of steam flow rate, the dryness fraction has to be included in the flow rate calculation; the dryness fraction is also a parameter that often needs to be monitored for effective process control and for condition monitoring of the plant. It is notoriously difficult, however, to measure dryness fraction easily and accurately. In this paper, an energy metering system which measures the steam quality, mass flow rate and thus the energy of the steam is proposed and tested. The system consists of a separator and condensate flowmeter followed by a steam flowmeter; the output signals of these devices are fed into a microcomputer which contains the characteristics of the devices and formulations for steam properties. Testing of the energy metering system showed that the average differences between the displayed output of the system and the values obtained using a condensate weightank was about 0.22% for the dryness fraction and 1.05% for the saturated steam flow rate.     

空压机冷凝液电子排放系统设计

介绍了冷凝液产生的原因及其对压缩空气系统的影响;对比了冷凝液的几种排放方法,讨论了冷凝液的排放与节能的关系;提出了电阻式与电容式两种电子液位检测与排放系统的设计。     

Wet surface heat transfer and pressure drop of aluminum parallel flow heat exchangers at different inclination angles

The effect of inclination angle on the heat transfer and pressure drop characteristics of brazed aluminum heat exchangers was experimentally investigated under wet conditions. Three samples having different fin pitches (1.25, 1.5 and 2.0 mm) were tested. Results show that heat transfer coefficients are not affected by the inclination angle. However, friction factors increase as the inclination angle increases with negligible difference between the forward and backward inclination. The effect of fin pitch on the heat transfer coefficient and on the pressure drop is also discussed. Comparison of the dry and wet surface heat transfer coefficients reveals that dry surface heat transfer coefficients are significantly larger than wet surface heat transfer coefficients. Possible explanation is provided by considering the condensate drainage pattern. The data are also compared with the existing correlation. This paper was recommended for publication in revised form by Associate Editor Man-Yeong Ha Nae-Hyun Kim is a Professor of Mechanical Engineering, University of Incheon. His area of interest spans boiling and condensation, heat transfer enhancement and heat exchanger design. He has been active in heat transfer community, and was a Chairman of Thermal Engineering Division of KSME. He holds several editorial position including Journal of Enhanced Heat Transfer. He is a recipient of Asian Academic Award awarded by SAREK and JSRAE.     

An experimental study of a two-phase closed loop thermosyphon with dual evaporator in parallel arrangement

A Two-phase Closed Loop Thermosyphon(TCLT) has been applied to many industrial fields as a waste heat recovery system, a telecommunication cooling system and other heat transport devices for the last 2 decades. It is common to design aTCL T to consist of one evaporator, one condenser and 2 separated lines of condensate liquid and vapor of working fluid. The present study was conducted in search of the new possibility of connecting multiple evaporators in parallel to the evaporator section. There has been little information about this so far. It is expected that aTCLT with multi-evaporator would provide a new solution to designing a compact telecommunication cooling system where lots of heat generating circuit boards are connected in parallel arrangement. In the present study aTCLT with two evaporators was prepared and given to a series of operational performance tests. The study was focused on investigating its operational problems and collecting information about its performances. Some important findings are as follows. The main source of operational instability was an occurrence of a hot dried patch on the heated surface when the rate of heat input was raised to a certain limit. For a single evaporator mode of the presentTCLT model, the maximum allowable heat transport rate was about 650W. For dual evaporator mode of operation, this instability problem was found to be closely related not only to the quantity of heat flux but also the difference in heat input rate to each evaporator. For all those problems, it was found that aTCLT with multi-evaporator could operate in a proper way when the thermal loads were evenly distributed to all the evaporator or the maximum power gap were contained under about ±5-7% of the average power input     

炼油厂钢管及其管道内部黑色沉积物的气相色谱-质谱分析

利用气相色谱 -质谱 ( GC/MS)技术和环境扫描电镜 ( ESEM)能谱分析 ,对炼油装置中发生管道“爆裂”的热交换器管道内部黑色沉积物进行了成分与来源分析。黑色沉积物含有碳、铁的氧化物、卤素、钾、镁、盐类和饱和脂肪烃。结果表明 :管道气体在炼制装置开停机的阶段 ,发生蒸汽冷凝沉积现象。沉积物与管道内壁发生化学反应 ,管壁受到严重腐蚀 ,使得热交换介质发生变化 ,不能再承受正常的应力负荷是发生爆裂的重要原因     

Film condensation on horizontal tube with wall suction effects

This study performs a theoretical investigation into the problem of two-dimensional steady filmwise condensation flow on a horizontal tube with suction effects at the tube surface. An effective suction function is introduced to model the effect of the wall suction on the thickness of the liquid condensate film. The local condensate film thickness and the local Nusselt number are then derived using a simple series numerical method. The results show that the Nusselt number varies as a function of the Jakob number Ja, the Rayleigh number Ra, and the suction parameter Sw. It is found that the wall suction effect has a significant influence on the heat transfer performance. An analytical solution is derived for the mean Nusselt number for the case in which the wall suction effect is ignored. Finally, a closed-form correlation is presented for the mean Nusselt number subject to a wall suction effect.