基于热力学第二定律的热交换器性能比较分析

针对热交换器换热过程,引入熵产单元数定量描述其不可逆程度,并建立熵平衡方程,利用Maple软件对比分析了两类熵产单元数与传热特性参数的关系。结果表明,传热效率、传热单元数、热容流量比、预热温度比、热端温度比是表征换热过程不可逆程度的主要参数,为基于热力学第二定律的热交换器的性能评价提供了理论依据,对节能工作具有重要参考价值。     

聚酯的热性能分析

使用DSC差示扫描量热仪对聚酯进行了热性能分析测试,分析了样品量和样品状态对聚酯热性能分析测试的影响,样品量的大小影响曲线图形,从而影响结晶度的准确分析判断。同等试样量时,整粒样品的熔点测定值略高于剪碎样品的熔点测定值。     

变换主热交换器“热激”防腐的可行性研究

本文阐述了变换主热交换器产生腐蚀的原因，介绍目前化工行业普遍采用的三种防后方法，指出这些防腐方法的不足之处，针对变换主热交换器防腐，提出了一种新的“热激”防腐方法，并提供具体设想和经济效益分析。     

用热重分析研究煤的结焦性能

采用非等温热重分析对煤结焦性能进行了试验，探讨了热解特征温度与塑性温度，失重速率峰温与煤化度的关系，并就升温速度的提高对煤结焦性能的影响以及煤岩显微组分的结焦性能等特点进行了研究。     

热交换器管子－管板的胀接性能

对锅炉、热交换器管子－管板胀接结构的安全及可靠性进行了实验研究。研究范围包括胀接结构的连接强度，密封即耐压性能，疲劳强度等。作者提供了初步的研究结果及试验数据，为设计、制造及研究工作者进一步认识胀接结构的特性，修改现行规范中的有关规定提供了依据。     

聚酯的差示扫描量热法热性能分析

使用DSC差示扫描量热仪分析了三种聚酯产品的热性能。同等试样量时,从测得试样的熔点、结晶度及曲线图形可以分析判断出,PET-2聚酯样品产品质量最好。     

钛系催化剂制备的聚酯热性能分析

对钛系催化剂制备的聚酯样品进行热性能分析研究。结果表明以钛催化剂合成的聚酯的热稳定性要稍好于以锑为催化剂合成的聚酯样品的热性能。     

水/二甘醇吸收式热变换器理论循环的性能分析

本文分析研究了水/二甘醇吸收式热变换器(Ⅱ型热泵)理论循环的性能,同时讨论和比较了表示系统性能的几种参数,提出了评价吸收式热变换器性能较全面的判据和供设计参考的公式。     

新型陶瓷换热器材料的实验研究

从多组实验配方中找出了一种耐热冲击性强、热膨胀性小、烧结致密的最佳配方。研究了几种主要陶瓷成分对陶瓷换热器抗热震性能的影响。     

Effects of fouling on performance of retrofitted heat exchanger networks: A thermo-hydraulic based analysis

The energy recovery performance of crude pre-heat trains (PHTs) in oil refineries is typically impaired by deposition over time of fouling on the thermal surfaces. Such time varying effects are normally not considered in the design or retrofit of heat exchangers networks. In this paper, the importance of taking into account such effects is demonstrated, by means of a case study. An existing industrial PHT network is simulated using a dynamic, distributed mathematical model for shell-and-tube heat exchangers undergoing crude oil fouling. To systematically assess the impact of fouling at the network level, several key performance indicators are proposed and used to analyse three retrofit options aimed at maximising overall heat recovery. Simulation results show that network designs that maximise energy recovery at steady state are not the best when fouling occurs. It is concluded that a proper retrofit design must include consideration of time varying fouling effects.     

巴基斯坦某项目贫富胺液换热器选型

阐述了巴基斯坦某项目的工艺流程,针对A包脱碳工艺流程中贫富胺液换热器进行详细的计算和选型,文根据板式换热器与管壳式换热器做出比选,为换热器的选型提供参考。     

Multi-period design of heat exchanger networks

Heat exchanger networks are an integral part of chemical processes as they recover available heat and reduce utility consumption, thereby improving the overall economics of an industrial plant. This paper focuses on heat exchanger network design for multi-period operation wherein the operating conditions of a process may vary with time. A typical example is the hydrotreating process in petroleum refineries where the operators increase reactor temperature to compensate for catalyst deactivation. Superstructure based multi-period models for heat exchanger network design have been proposed previously employing deterministic optimisation algorithms, e.g. (0005 and 0180). Stochastic optimisation algorithms have also been applied for the design of flexible heat exchanger networks recently (0110 and 0115). The present work develops an optimisation approach using simulated annealing for design of heat exchanger networks for multi-period operation. A comparison of the new optimisation approach with previous deterministic optimisation based design approaches is presented to illustrate the utilisation of simulated annealing in design of optimal heat exchanger network configurations for multi-period operation.     

Experimental performance comparison of shell-side heat transfer for shell-and-tube heat exchangers with middle-overlapped helical baffles and segmental baffles

Presented in this paper are experimental test and comparison for several shell-and-tube heat exchangers, one with segmental baffles and four with helical baffles at helix angles of 20^°, 30^°, 40^° and 50^°, respectively. The results show that, based on the same shell-side flow rate, the heat transfer coefficient of the heat exchanger with helical baffles is lower than that of the heat exchanger with segmental baffles while the shell-side pressured drop of the former is even much lower than that of the later. Further enhancement techniques should be incorporated in order to enhance shell-side heat transfer based on the same flow rate. The comparison of heat transfer coefficient per unit pressure-drop (and pumping power) versus shell-side volume flow rate shows that (1) the heat exchanger with helical baffles have significant performance advantage over the heat exchanger with segmental baffles; (2) for the same shell inner diameter, the performance of heat exchanger with helical baffles with 30° helix angle is better than that of 20°, and the performance of 40° helix angle is better than that of 50° helix angle. The heat exchanger with helical baffles of 40° angle shows the best performance among the five heat exchangers tested.     

插入扰流元件换热管强化换热效果分析

设计了一种新型插入扰流元件管式换热器,并依据相关文献的模拟数据将其与波纹管、光管在不同流速下的管内壁面平均传热系数、换热量、平均Nusselt数以及摩擦阻力的变化特性进行了分析比较。结果表明:插入扰流元件换热管在强化换热能力的同时其压力损失也会很大,所以在实际应用过程中选取插入扰流元件换热管时一定要考虑其经济性;在泵功率消耗一定时,插入扰流元件换热管的热效率与波纹管的热效率很接近。但插入扰流元件换热管在制造工艺上具有加工方便、固定灵活等优点,比较适合对现有换热器的改造。所以,该种热管同样具有广泛的应用价值。     

热管换热器与给水预热器的性能比较

针对热管换热器与给水预热器在酒钢焦化厂一期与二期干熄焦中的应用性能进行比较,阐述了热管换热器与给水预热器在干熄焦系统中应用的优缺点。     

复合管板结构在换热器设计中的应用

在硫铵用换热器设计中 ,采用碳钢管板衬一层不锈钢薄板结构。管板设计时 ,碳钢管板的厚度应满足设计厚度 ,管板与换热管的焊缝满足拉脱应力强度 ,碳钢管复层满足防腐要求。给出了管板的设计结构图。因换热管伸出碳钢管板长度大于GB 15 1- 89中的规定长度 ,换热管与管板焊缝的有效截面积大于标准中的规定 ,从而保证了管板与换热管的拉脱应力强度。     

Design of flexible heat exchanger network for multi-period operation

Heat exchanger networks (HENs) increase heat recovery from industrial processes by matching hot and cold streams to exchange heat and reducing utility consumption. The design of HENs is a very complex task which generally involves mixed-integer non-linear programming (MINLP).This work evaluates and critically compares existing HEN design methods. It then presents a systematic methodology in the design of HENs under multiple periods of operation. The model presented in this work is a superstructure-based MINLP model which minimises the total annualised cost containing heat exchanger area cost and utility costs. The model is based on the superstructure by Yee and Grossmann [1990. Simultaneous optimisation models for heat integration—II, heat exchanger network synthesis. Computer & Chemical Engineering 14(10), 1165-1184], which was later formulated for multiple periods by Aaltola [2002. Simultaneous synthesis of flexible heat exchanger network. Applied Thermal Engineering 22, 907-918]. It includes a multi-period simultaneous MINLP model to design the HEN structure, and an NLP model to improve the solution and allow for non-isothermal mixing. Modifications to Aaltola's model include the use of maximum area per period in the area cost calculation of the MINLP objective function, and the removal of slack variables and weighed parameters from the existing NLP improvement model.The new model has been applied to one industrial case study, demonstrating that the new combined MINLP-NLP model can obtain better solutions by not relying on the average area assumption in the MINLP stage.     

第一热交换器管间的适宜板间距

根据热力学和传递过程的基本理论，对小氮肥厂变换工序的第一热交换器壳程进行用分析．并以损失为评价准则探讨适宜的档板间距选取问题。