余压能量回收装置在湿法脱碳工艺中的应用

介绍了能量回收透平、涡轮增压器、功交换器等余压能量回收装置的基本流程;简述了余压能量回收装置在我国湿法脱碳工艺中的应用情况;对比分析了上述3种余压能量回收装置的优缺点。结果表明,涡轮增压器具有占地面积小、易于安装、运行周期长、能量回收效率高（达80%以上）等优势,若将其应用于现有脱碳系统的改造及低温甲醇洗工艺,将会产生良好的节能效果和经济效益。     

板式换热器在天然气净化装置中的应用

板式换热器具有体积小、重量轻、换热效率高等特点,可大大降低装置的能耗、操作费用,取得了较好的经济效益。本文结合工厂实际,比较了管壳式换热器和板式换热器的优缺点,主要介绍了新型板式换热器在天然气净化装置中的应用。     

膨胀制冷技术在管壳式换热器中的应用

某海上油田陆岸终端轻烃回收系统未凝气闪蒸罐气相出口管壳式换热器采用淡水冷却,由于天然气处理量增加,管壳式换热器制冷效果不能达到设计要求的影响,未凝气闪蒸罐运行压力一直偏高,导致轻烃和重烃分离不完全,部分重烃在系统中重复处理,部分液化气进入常压轻油储罐而损失。文章利用天然气在该工艺流程段多余势能,将膨胀制冷技术集成至管壳式换热却器,天然气经过膨胀后降温和水冷降温,提高了轻烃和重烃的分离效果,降低了未凝气闪蒸罐运行压力,避免了液化气的浪费,减少了淡水的消耗,提高了该系统的运行效率,取得了较好的经济效益与社会效益。     

Prediction of thickness and fouling rate in pulsating flow heat exchangers,using FLUENT simulator

Heat exchangers are an important part of industrial processes as they handle a major portion of total energy consumption. Fouling could have serious impact on their performance and hence affect the economic performance of the process plant. The aim of this work was to simulate the crystallization fouling process in a heat exchanger by developing a C⁺⁺ program and adopting UDF functions through Fluent software; and hence evaluate all the given models and consequently implement the model which would best suit our particular case. The finding of this work would enable us to evaluate the thickness and fouling rate in the heat exchangers. Furthermore, the effect of pulsating flow on the crystallization fouling of calcium sulfate (CaSO₄) in the heat exchanger was also investigated, and the effect of operation of different amplitude of the oscillations (10–70) and frequencies (1.59–12.73 Hz) on the fouling of this compound was studied.     

采用换热器负荷图指导换热网络改造的新方法

目前大部分图形工具仅适用于以节能为目标的换热网络（HEN）设计或者改造。能量回收量的增加往往伴随换热单元数的增多,而换热单元数对设备投资费有较大影响。采用换热器负荷图（HELD）提出一种系统化的换热网络改造新方法。新方法基于夹点分析,在改造区间中选择匹配目标,重新构建改造用HELD,从而简化问题;通过在水平方向上平移热流股曲线实现跨夹点负荷的重新分配,完成节能目标,并结合经验规则,尽可能减少改造后换热网络的换热器数目。以一个工业造纸厂为例,对其进行节能改造方案设计,相较于文献报道结果,得到两个节能目标值相近且换热器改动数目更少的新方案,验证了新方法的有效性。     

热管技术在化工余热回收中的应用

通过实例介绍了多种热管式换热器在化工领域余热回收中的应用,回收废烟气中的热量来预热空气、水,以及生产蒸汽;分析了热管换热器使用中的问题,并提出了解决方法;此外,还首次提出了利用密闭腔式换热器来回收废液及废蒸汽中低品位热量的可行性。这对于化工企业的节能降耗具有指导意义。     

Optimal operation of heat exchanger networks through energy flow redistribution

This article presents a novel energy flow redistribution methodology to achieve optimal operation of heat exchanger networks. The proposed method aims to manipulate the propagation path of a disturbance through the network to reduce its impact on utility consumption. Specifically, an optimization problem is formulated to generate new duty targets for heat exchangers of the network when a disturbance is encountered. Subsequently, a feedback control system is designed to track these targets by manipulating bypasses around the process heat exchangers. The effectiveness of the proposed framework is illustrated with the help of three benchmark examples. The proposed approach can handle disturbances in inlet as well as target temperature, inlet flow and heat transfer coefficient of individual heat exchangers.     

采用双(多)壳程换热器来促进换热网络的进一步优化

文中从过程工业换热流程优化的角度论述了采用双（多）壳程换热器的重要性和必要性,并从单个匹配和整个换热网络两方面进行了理论分析,指出采用双（多）壳程换热器具有降低换热器投资,提高换热网络热回收率和过程系统的能量综合优化化水平等多重效果。     

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.     

螺旋扭曲管用于燃气轮机进气温度调节换热器的可行性研究

对将螺旋扭曲管用于燃机进气温度调节换热器进行可行性分析,模拟燃机进气加热器实际运行的工况条件进行综合传热性能实验研究,得到了传热与流阻准则关系式;引入综合评价因子概念并与传统钢铝翅片管换热器进行对比发现,螺旋扭曲管换热器是钢铝翅片管换热器的1.31~1.52倍。以某建设项目采用的E级PG9171E型机组为例,对采用螺旋扭曲管和钢铝翅片管的两种进气温度调节换热器进行对比发现：当采用螺旋扭曲管换热器时,在同样换热能力下,换热器风侧阻力增大了14.7%;在同等质量下,换热器换热能力提高9.9%左右。     

降低再热能耗的空调热回收系统分析

为降低一次回风全空气空调系统空气处理机组再热能耗,提出两种改进空调热回收系统,分别是混风热回收系统和新回风热回收系统。基于空调系统空气处理流程的分析,结合热力学第一定律、空气处理机热质传递方程,建立了这两种空调热回收系统能耗的计算模型。在此基础上,以昆明地区为例,考察了空调室外新风参数、空调区域热湿比、新风量及送风量等主要因素对热回收系统能耗与效率的影响,并与常用回风热回收系统和一次回风系统进行了比较。研究结果表明,在温和地区采用新提出的两种热回收系统均比一次回风系统节能60%左右,消除了一次回风全空气系统存在的“冷热抵消”现象;新提出的两种热回收全空气系统能有效减少换热器初投资,缩短热回收设备投资回收期。     

基于智能预测和机理模型的换热网络清洗决策

原油石化装置的换热器常受到结垢影响,导致换热器性能衰退严重,换热网络性能也会随之衰退,同时换热器之间的耦合关系,导致不同换热器的性能衰退对换热网络整体性能变化的影响不同。以往的清洗决策主要是根据单台换热器性能衰退到一定程度来制定的,这会导致换热网络整体可能处在较差的运行状态。因此,本文提出一种基于智能预测和机理模型的换热网络清洗决策方法,基于换热器的运行数据建立智能预测模型,获得换热器性能变化趋势,结合换热网络的性能模拟模型,进一步获得换热网络的性能变化趋势,从而从换热网络整体性能变化的角度来制定清洗方案。研究表明,对收集到的原油换热器运行数据,建立神经网络预测模型,具有较好的预测精度。通过对原油精馏装置换热网络的案例分析,当HE1、HE2和HE5三台换热器同时发生性能衰退时,换热网络年度公用工程能耗费用将增加12.1%。与传统基于单台换热器性能衰退情况制定的清洗方案相比,从换热网络整体性能衰退角度制定的清洗方案,年度额外公用工程费用减少13.1%,损失费用减少14.1%,年度总费用减少13.8%,而清洗次数仅增加3台次。     

Fresh water by reverse osmosis based desalination: simulation and optimisation

The reverse osmosis (RO) desalination process to make fresh water from seawater has been studied here. First, a model for the process is developed. Sensitivity of different operating parameters (feed flow rate, feed pressure) and design parameters (internal diameter, total number of tubes) on the recovery ratio are studied via repetitive simulation. Finally, an optimisation framework for the process is developed so as to maximize the recovery ratio or a profit function using different energy recovery devices, subjectto general constraints. The optimal operating parameters (feed flow rate, feed pressure) and design parameters (internal diameter, total number of tubes) are determined by solving the optimisation problem using an efficient successive quadratic programming (SQP) based method. The optimal values for the decision variables depend on the constraints introduced, and are also sensitive to variations in water and energy prices, as well as feed concentration. The use ofthe emerging energy recovery devices is widely justified, reporting much higher reductions in operating costs than the traditional technology used for this purpose. Using a pressure exchanger device, it is possible to reduce energy consumption by up to 50%.     

Numerical investigation of grooves effects on the thermal performance of helically grooved shell and coil tube heat exchanger

Heat exchangers are integral parts of important industrial units such as petrochemicals, medicine and power plants. Due to the importance of systems energy consumption, different modifications have been applied on heat exchangers in terms of size and structure. In this study, a novel heat exchanger with helically grooved annulus shell and helically coiled tube was investigated by numerical simulation. Helically grooves with the same pitch of the helical coil tube and different depth are created on the inner and outer wall of annulus shell to improve the thermal performance of heat exchanger. In the first section, thermal performance of the shell and coil heat exchanger with the helical grooves on its outer shell wall was compared with same but without helical grooves. At the second section, helically grooves created on both outer and inner wall of the annulus shell with different groove depths. The results showed that the heat exchanger with grooves on both inner and outer shell wall has better thermal performance up to 20% compared to the heat exchanger with grooves on only outer shell wall. The highest thermal performance achieves at lower flow rates and higher groove depths whereas the pressure drop did not increase significantly.     

Hydraulic turbine energy recovery - R.O. System

In reverse osmosis desalination plants large flow rates of concentrated brine are discharged at high pressure from the membrane modules. Currently this pressure energy is wasted. This paper reviews the impact of soaring energy costs on the technical alternative of hydraulic turbine energy recovery. The capital costs, operating costs, and economics in electrical energy are evaluated for both sea-water and brackish water systems. Schemes of hydraulic turbine coupled with electric generator, tied to the electric power supply are considered for various plant sizes from 1 to 10 mgd. The analysis, in parametric form, presents the interrelationships between the cost of money, cost of electrical energy, and recovery factors for the different plant sizes and for sea-water and brackish water systems. The results will serve as a guide to determine when such a power recovery system should be seriously considered and evaluated in greater details for specific applications.     

基于实际热负荷分布的换热网络优化改造

采用非等温混合分流分级超结构,建立了基于实际热负荷分布的换热网络改造模型,以由改造费用和运行费用组成的年度化总成本为目标,并采用遗传算法进行求解。改造费用涉及现有换热器增加换热面积、配置新换热器、重新布置管道以及移动现有换热设备所产生的费用,充分考虑了原有换热网络经改造后结构的变化所引起的改造成本。在回用原有换热设备后,根据设备实际面积来计算换热网络的热负荷分布和温度分布,即基于实际热负荷分布对换热网络进行改造。案例研究表明,改造后的换热网络结构具有良好的节能效益,合理地再利用了原网络中的旧换热设备,并以较少的改造成本实现了较高的能量回收,投资回报期仅为0.43年,验证了所提改造方法的有效性和实用性。     

Catalytic oxidation of natural gas using flameless burners of a new design

Various aspects of operating burners traditionally used for oxidizing gaseous hydrocarbons and heat exchangers used for heat recovery are considered. A method developed by FAST ENGINEERING LTD. for the efficient burning of fuel with deep heat recovery of waste gases while maintaining a given adiabatic temperature is described. The method is based on using a flameless burner and heat exchangers of a new design. Burner operation is tested on an experimental stand with determination of the dependences for the aerodynamic drag of a granular layer and the content of unburned hydrocarbons, CO, and NO _x in combustion products on the consumption of the fuel-air mixture and the adiabatic temperature of fuel combustion. The described method for burning fuel is shown to provide the desired temperature of combustion products for a consumer of heat energy and to reduce the consumption of fuel by 5–20%. Burning fuel at an adiabatic combustion temperature of no more than 1200°C virtually eliminates the CO and NO _x content in the combustion products. Designed flameless burner, new generation of heat exchangers, and technology for the efficient burning of fuel can be applied to vapor and water-heating boilers, gas turbines, and catalytic reactors to produce synthesis gas from natural gas for processing into hydrogen, ammonia, methanol, synthetic liquid hydrocarbons, and so on.     

乙烯热泵系统的换热网络分析

夹点技术在石油化工行业换热网络分析中广泛应用,依据夹点技术的基本原理与设计原则,利用Aspen Energy Analyzer软件对某大型乙烯装置中的乙烯热泵系统换热网络进行了分析。分别对增加换热器消除跨夹点传热及改变乙烯塔操作压力2种情况下的换热网络进行了分析。结果表明,工艺设计过程中不应只单纯追求无跨越夹点传热和低能耗,应综合考虑一次投资、操作费用及投资回收周期,从而经济、合理地综合评价能耗。     

Waste heat powered reverse osmosis plants

The purchased power required for operation of reverse osmosis systems can be greatly reduced or sometimes eliminated by reclaiming waste heat from diesel engines, gas turbines, flare gases, etc. This can be accomplished by using a Biphase turbine to convert low level waste heat to shaft horsepower.The system can be designed to use waste heat from existing installations or to reduce the size of the generating equipment in new supplies.The Biphase conservation turbine is driven by a two phase stream generated by flashing a superheated liquid through a nozzle to the turbine. The turbine can be directly coupled to a pump shaft, to an electrical generator or to a combination of the two. Performance of the turbine is discussed. The waste heat recovery turbine and a hydraulic turbine to recover energy from the high pressure concentrated brine can be combined into one system.This paper describes the design of a seawater reverse osmosis system using waste heat from an existing diesel generating unit. The SeaRO system is designed to produce 750 cmd of 400 ppm water at an energy consumption of approximately 2.5 KWH of purchased power per cubic meter.A discussion of available desalination capacity at various quantities and temperature levels of the waste heat source is presented. A comparison of water costs obtained using this system and a conventional electrical drive is presented.