TP316L不锈钢管在以中水作为循环水补水的凝汽器中的应用

中水对凝汽器铜管腐蚀性强,导致凝汽器频繁发生泄漏。通过采用TP316L不锈钢管替代铜管,并做好不锈钢管的安装及运行维护工作,解决了中水对凝汽器管的腐蚀问题,保证了凝汽器安全运行。     

304不锈钢管凝汽器腐蚀原因研究

进行了不锈钢管、水处理药剂和酸洗液的腐蚀性能试验。凝汽器304不锈钢管发生点蚀的主要原因是不锈钢管质量不合格和使用的酸洗液不当。不锈钢酸洗液腐蚀性能的评价不能采用腐蚀失重法。订合同时应写入按照ASTM A249中S7条款检验不锈钢管焊缝质量。     

不锈钢管在凝汽器上的应用

为应对电厂循环水质日益恶化的状况,根据采用不锈钢管作为凝汽器冷却管的经验,从物理特性、化学特性等多方面,分析、说明不锈钢管因其卓越的耐蚀性、耐冲击性、较好的传热性能以及良好的经济性和可靠性,在凝汽器上具有广阔的应用前景。     

汽轮机凝汽器铜管的腐蚀与防护

铜管在汽轮机凝汽器中使用非常频繁,凝汽器铜管腐蚀泄漏严重威胁到机组安全经济运行;据资料统计,因凝汽器铜管腐蚀泄漏造成汽轮机停机的事故非常多。在凝汽器运行过一程中保护凝汽器铜管少受腐蚀或不受腐蚀就显得非常重要。     

提高35MW汽轮发电机组运行经济性的探索

介绍河北钢铁集团承钢公司能源中心对35MW汽轮机组调速系统进行改造的实践过程,通过采取更换凝汽器铜管为不锈钢管,增加胶球清洗装置,控制高炉鼓风机运行工况点等措施,解决了调速系统卡涩这一困扰汽轮机组生产安全与稳定的问题,实现了控制腐蚀速率及凝汽器的在线清洗,提高了汽轮机组的运行稳定性,降低了机组汽耗率,达到了减少排风,节约能源的目的,取得了较好的经济效益。     

提高凝汽器不锈钢换热管寿命分析及采取措施

凝汽器不锈钢换热管在凝汽器上的应用越来越普及,除了以海水作为冷却介质外几乎其它冷却水全部采用不锈钢管。保证换热管长期运行是凝汽器安全运行也是汽轮机组安全运行的前提条件,从分析换热管材的特性入手,提出在凝汽器设计及安装、运行维护方面的注意事项及采取的相应措施。     

630MW机组凝汽器换管改造后性能及经济性分析

介绍扬州第二发电有限责任公司630MW亚临界机组配套凝汽器的运行特性,针对凝汽器运行现状和存在的问题,分析原因,并提出凝汽器铜管更换为不锈钢管的改造方案;通过凝汽器改造前后参数的对比分析凝汽器改造后的性能及节能效果,各项性能指标基本达到了预期的改造目标和效果,经济性明显提高,运行良好。为同类机组的凝汽器换管改造工作提供一些参考。     

350 MW凝汽式机组化学循环水补水方式改进的技术探讨

分析了河津电厂350MW凝汽式汽轮机凝结水系统中凝汽器铜管出现严重腐蚀的原因。叙述了通过改变循环水补水方式，降低凝汽式机组中凝汽器铜管腐蚀程度的方法，指出该方法可降低凝汽机组中凝汽器铜管的腐蚀的结论。     

铜陵电厂凝汽器黄铜管换不锈钢管

经过多方面的调查、试验和研究,铜陵电厂将1号机凝汽器HSn70-1黄铜管全部换成了304不锈钢管,与黄铜管相比,不锈钢管具有较好的耐蚀性能、机械性能、经济性能,,总的传热性能也不差,取得了较好的效果。     

大型汽轮机凝汽器改造可行性研究

大型汽轮机凝汽器将冷却管由铜管改造为不锈钢管已发展成为一种趋势,然而国内很多机组在决策是否进行改造工作时存在盲目性。通过大型汽轮机凝汽器改造可行性研究,提供了凝汽器改造收益和投资回报计算方法,并重点分析了凝汽器实际运行性能对改造工作投资收益的影响,为大型汽轮机凝汽器改造的决策工作提供了指导建议和决策方法。     

Effects of Airflow Profile and Condensation Pressure on Performance of Air-Cooled Condensers

Abstract

The effect of airflow profile and condensation pressure on the performance of air-cooled condensers is investigated experimentally. Two large, flattened-tube air-cooled steam condensers are studied. The tube lengths are 10.7 and 5.7?m, with inner dimensions of 216?×?16?mm and aluminum fins on each side of the elongated-slot cross sections. Capacity and pressure drop are measured and discussed here. All tests are performed with a horizontal tube and co-current vapor and condensate flow. Four different profiles of cross-flowing air are tested: uniform air flowing upwards, uniform air flowing downwards, and two profiles of non-uniform air flowing upwards. For the 10.7?m tube, reversing airflow direction from upwards to downwards is found to significantly increase condenser capacity. Also for the 10.7?m tube, a favorable non-uniform air-velocity profile is shown to increase capacity in comparison to a uniform air-velocity profile. Both of these performance increases are shown to be the result of matching regions of maximum heat transfer coefficient on the air and steam sides. For the 5.7?m tube, a non-uniform airflow profile is shown to have no effect on capacity. Reducing condensation pressure is shown to decrease condenser capacity for both condenser tubes.     

Numerical investigation of a two-stage air-cooled absorption refrigeration system for solar cooling: Cycle analysis and absorption cooling performances

Two-stage air-cooled ammonia–water absorption refrigeration system could make good use of low-grade solar thermal energy to produce cooling effect. The system simulation results show that thermal COP is 0.34 and electrical COP is 26 under a typical summer condition with 85 °C hot water supplied from solar collector. System performances under variable working conditions are also analyzed. Circular finned tube bundles are selected to build the air-cooled equipment. The condenser should be arranged in the front to get an optimum system performance. The mathematical model of the two-stage air-cooled absorber considering simultaneous heat and mass transfer processes is developed. Low pressure absorber should be arranged in front of middle pressure absorber to minimize the absorption length. Configuration of the air-cooled equipment is suggested for a 5 kW cooling capacity system. Temperature and concentration profiles along the finned tube length show that mass transfer resistance mainly exists in liquid phase while heat transfer resistance mainly exists in cooling air side. The impacts on system refrigeration capacities related to absorption behaviors under variable working conditions are also investigated. Both cycle analysis and absorption performances show that two-stage air-cooled ammonia–water absorption chiller is technically feasible in practical solar cooling applications.     

凝汽器和低压加热器换热管采用不锈钢材质的趋势

介绍了凝汽器和低压加热器的汽、水侧的腐蚀类型和机理，从亚临界、超临界、空冷和核电机组运行参数的要求出发，给出在某一特定情况下换热管采用不锈钢材质的原由和发展方向；乃至冷却水的现状——高度工业化带来的严重污染及对给水水质的苛刻要求，尤其是超临界机组防止铜的析出、空冷机组与铝制散热器的电化学腐蚀等诸方面详细论述了换热管采用不锈钢材质更是势在必行。     

Space characteristics of the thermal performance for air-cooled condensers at ambient winds

Ambient winds may lead to poor fan performance, exhaust air recirculation and mal-distribution of the air across the tube bundles of the air-cooled condensers in a power plant. Investigations of the impacts of the ambient winds on the air-cooled condensers are key area of focus. Based on a representative 2 × 600 MW direct dry cooling power plant, the physical and mathematical models of the air-side fluid and heat flow in the air-cooled condensers at various ambient wind speeds and directions are set up by introducing the radiator model to the fin-tube bundles. The volumetric flow rate, inlet air temperature and heat rejection for different air-cooled condensers as a whole, condenser cells and fin-tube bundles are obtained by using CFD simulation. The results show that the thermo-flow performances for the air-cooled condenser as a whole, condenser cells and heat exchanger bundles vary widely in space. The thermal performances of the air-cooled condensers, condenser cells and fin-tube bundles at the downstream are generally superior to those at the upwind. It is of use for the upwind fan regulations and the A-frame condenser cell geometric optimization to investigate the space characteristics of the thermal performance for the air-cooled condensers in a power plant.     

Flow Patterns for Isothermal Condensation in One-Pass Air-Cooled Heat Exchangers

An analytic method is developed to describe the flow in each row of tubes of an air-cooled one-pass isothermal condenser. This leads to a better understanding of some common steam condenser problems, including freezing of condensate, rapid tube-side corrosion, and worse performance than predicted by any reasonable condensing coefficient. The NTU approach is used to derive expressions for pressure drop in each row in terms of exchanger effectiveness. The resulting simultaneous equations are solved numerically, and the solutions, presented graphically, show the flow pattern to be solely a function of effectiveness. For steam condensers contaminated by traces of air, it is found that air pockets will develop inside the tubes of the lower rows, blanketing the surface and preventing condensation. Several designs are described that attack the problem of noncondensable accumulation, including the most recent developments in the air-cooled condenser field.     

三角扰流蛇形翅片管流动换热特性数值研究

蛇形翅片管作为空冷凝汽器基本换热面,其流动与换热性能对空冷电站经济性有着重要影响,基于此,对三角扰流蛇形翅片管的气侧换热及流动特性进行了数值研究,分析了流体温度、压力沿流程方向的变化规律以及迎面风速、扰流三角个数、扰流三角尺寸等因素对蛇形翅片管换热及流动性能的影响,结果表明三角扰流部位局部阻力是沿程阻力的25%～70%,扰流三角对换热有明显的促进作用,换热系数最大提高37%.本研究可为蛇形翅片管的设计及优化提供理论参考.     

基于模糊层次分析法的直接空冷凝汽器防冻性能监测

以某300MW直接空冷机组为例,分析了影响直接空冷凝汽器防冻性能的主要因素,基于模糊层次分析法,建立了直接空冷凝汽器防冻性能监测模型．结果表明：凝结水与抽空气温度偏差等因素对防冻性能的影响较大;该空冷凝汽器的第2排和第5排散热管束的防冻性能较差;基于模糊层次分析法所建模型不仅能对空冷凝汽器防冻性能进行定量评价,还能缩小查找结冰故障的范围,为结冰故障的预防、采取预处理措施、实施冬季优化运行奠定基础．     

Multiple bed regenerative adsorption cycle using the monolithic carbon–ammonia pair

A refrigeration/heat-pump system based on a number of simple tubular adsorption modules is described. A single module is comprised of a generator and a receiver/condenser/evaporator. A single generator consisting of a 12.7 mm stainless steel tube lined with 2.6 mm of monolithic active carbon has been manufactured. A complete module has been tested in a simple rig, which subjects it to alternating hot and cold airstreams, desorbing and adsorbing ammonia. A complete system, consisting of 32 modules has been modelled in detail and its predicted performance is presented. Key parameters have been varied and their effect on the performance discussed.