Feasibility Analysis of Back-Pressure Steam Feeding Water Pump for Direct Air-Cooled Unit

As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introduces a new design of for steam feeding the water pump of an air-cooled unit using the back-pressure steam turbine as the prime motor. Using variable condition analysis on a 600 MW direct air-cooled unit, and with consideration of the effect on the ambient conditions, the feasibility, economy, and adaptability of the design are verified.

Simulation of Underground Reservoir Stability of Pumped Storage Power Station Based on Fluid-Structure Coupling

Based on global initiatives such as the clean energy transition and the development of renewable energy,the pumped storage power station has become a new and significant way of energy storage and regulation,and its construction environment is more complex than that of a traditional reservoir.In particular,the stability of the rock strata in the underground reservoirs is affected by the seepage pressure and rock stress,which presents some challenges in achieving engineering safety and stability.Using the advantages of the numerical simulation method in dealing deal with nonlinear problems in engineering stability,in this study,the stability of the underground reservoir of the Shidangshan(SDS)pumped storage power station was numerically calculated and quantitatively analyzed based on fluid-structure coupling theory,providing an important reference for the safe operation and management of the underground reservoir.First,using the COMSOL software,a suitablemechanicalmodel was created in accordance with the geological structure and project characteristics of the underground reservoir.Next,the characteristics of the stress field,displacement field,and seepage field after excavation of the underground reservoir were simulated in light of the seepage effect of groundwater on the nearby rock of the underground reservoir.Finally,based on the construction specifications and Molar-Coulomb criterion,a thorough evaluation of the stability of the underground reservoir was performed through simulation of the filling and discharge conditions and anti-seepage strengthening measures.The findings demonstrate that the numerical simulation results have a certain level of reliability and are in accordance with the stress measured in the project area.The underground reservoir excavation resulted in a maximum displacement value of the rock mass around the caverns of 3.56 mm in a typical section,and the safety coefficient of the parts,as determined using the Molar-Coulomb criterion,was higher than 1,indicating that the project as a whole is in a stable state.

Development and Application of a Shaft-type Tubular Pumping System with a Siphon Discharge Passage

Based on the characteristics of large flow rate , low head , short annual operation time , and high reliability of the city flood-control pumping stations , a new-type shaft tubular pumping system featuring a shaft suction box and a siphon-type discharge passage with a vacuum breaker as the cutoff device was developed , which possesses such advantages as simple structure , reliable cutoff , and high energy performance.Taking some pumping stations as the case studies , in the light of the specified operation conditions , the hydraulic optimal design of the shaft-type tubular pumping system was determined and the optimized shape of the system was recommended.The performance prediction based on the computational fluid dynamics methodology was determined and the model test verification was conducted.The results show that the predicted data agree with the experimental head and efficiency so that both methods can be used to determine the performance of a real pumping station.Finally , the in-situ measurements of a pumping station during the commissioning period further verified that the shaft-type tubular pumping station with a siphon discharge passage is of higher efficiency , more reliable and stable.

Cross influence of discharge and circulation on head loss of conduit of pump system with low head

The relationship between the head loss and the discharge and circulation of the conduit of a pump system with low head is an important problem with an obvious influence on the improvement of its hydraulic performance. The velocity circulation from the pump guide vane makes the relationship more complicated, which has to be understood comprehensively. The results indicate that, under the condition of zero circulation, the head loss of the inlet and outlet conduits is in proportion to the square of discharge. Under the condition that the Reynolds number is satisfied with the resistant square area, the conduit loss is in proportion to the square of discharge for the similar working points with different speeds in a certain rotational speed range, indicating that the pump system efficiency is constant. The outlet conduit loss of design discharge for a pump system with low head depends on the velocity circulation from the guide vane exit, and the relationship between the loss and the circulation is an open curve with an upward direction, meaning that there is an optimal circulation for the loss. Under the condition of various working points for a pump system with low head, the head loss of the outlet conduit is under the cross influence of both the discharge and the circulation. As a result, the relationship between the head loss and the discharge is almost linear, and the mechanism needs to be further studied.

Modeling a high output marine steam generator feedwater control system which uses parallel turbine-driven feed pumps

Parallel turbine-driven feedwater pumps are needed when ships travel at high speed. In order to study marine steam generator feedwater control systems which use parallel turbine-driven feed pumps, a mathematical model of marine steam generator feedwater control system was developed which includes mathematical models of two steam generators and parallel turbine-driven feed pumps as well as mathematical models of feedwater pipes and feed regulating valves. The operating condition points of the parallel ttu-bine-driven feed pumps were calculated by the Chebyshev curve fit method. A water level controller for the steam generator and a rotary speed controller for the turbine-driven feed pumps were also included in the model. The accuracy of the mathematical models and their controllers was verified by comparing their results with those from a simulator.

Efficiency in Boiler Feed Pumps for Industrial Steam Generation

This paper presents some opportunities to improve feedwater system efficiency for industrial boilers, usually consisting of multistage centrifugal pumps driven by three-phase induction motors. There is abundant literature on the efficiency in steam boilers. However, few deal exclusively with feedwater systems. The total horsepower in boiler feed pumps and the corresponding energy consumption estimated for Brazilian industries are as follows： 110.5 MWE of motor driven power and a yearly electricity consumption of 442 GWh for a population of 7,800 steam boilers, approximately. It is estimated that there can be an efficiency improvement in feedwater systems for industrial boilers of 30% on average. To a large extent, these opportunities reside in older boilers that are very common in the Brazilian industrial sector. The most common causes for the low efficiency of feedwater systems are： the control loop of the feedwater, oversized boilers and excessive operational pressure set. Sometimes, the boiler feedwater system can present more than one problem simultaneously. Any kind of solution involves some speed regulation, new pump and number of pumps. Each problem generation facilities were selected in which common inefficiencies cases, the improvement in efficiency can get to 37%. form of intervention in boiler feed pumps, such as： impeller trim, may have more than one solution. Three distinct industrial steam are present. The suggested solutions were analyzed. In these three

混合式抽水蓄能电站对下泄水温影响的数值模拟研究

【目的】混合式抽水蓄能电站运行特性与常规电站相比存在差异,本文旨在掌握抽水蓄能电站水温的变化规律,为水库管理调度提供参考。【方法】以紧水滩水库为研究对象,采用MIKE3水温模型模拟不同进/出水口高程以及不同抽水流量工况的下泄水温,据此探讨混合式抽水蓄能电站对下泄水温的影响。【结果】抽蓄水流会对下泄水温产生影响,相对于现状无抽水工况的下泄水温,抽蓄工况下的下泄水温基本表现为5—9月略有下降,其余月份略有升高,下泄水温的最大降幅不超过0.7℃,最大升幅不超过0.8℃。【结论】进/出水口高程对于下泄水温影响较大,且高程越低,下泄水温差异越大。然而抽水流量对于下泄水温差异影响并不显著,但整体上也呈现出随着抽水流量增加,水温差异增大的趋势。

浑源抽水蓄能电站下水库拦排沙系统防沙效果的试验研究

设置拦排沙系统是缓解抽水蓄能电站泥沙问题的有效方法之一。为验证浑源抽水蓄能电站下水库拦排沙系统的防沙效果,建立了浑源抽水蓄能电站下水库泥沙物理模型,进行了不同频率洪水入库试验。通过比较有、无拦排沙系统的输沙量及悬沙特性,论证了拦排沙系统的拦沙效果,并分析了影响拦沙效果的主要因素。结果表明:不建拦沙坝情况,进入下水库的泥沙直接相关于上游水沙条件,其相关系数大于0.8;修建拦排沙系统后,进入下库沙量明显减少、悬沙粒径细化,拦沙效果与拦沙库淤积情况的相关系数均大于0.7,拦沙库的淤积情况是拦沙效果的主要影响因素,而上游水沙条件的影响较小。

热泵辅助无规填料表面蒸发装置浓缩热敏料液性能研究

目的:设计一种低能耗、可在常压下低温浓缩热敏料液的表面蒸发浓缩装置。方法:建立装置的基本方程,分析体积蒸发通量和节能倍率随料液流量、料液温度、吹扫气流量、吹扫气温度的变化规律,制作试验台并通过试验得出一组最佳性能参数。结果:当料液流量为0.02 kg/s时,装置具有最高的节能倍率和较高的体积蒸发通量;当料液温度从30℃增加到50℃时,体积蒸发通量增加了224.68%,但节能倍率降低了12.42%;当吹扫气流量从0.004 kg/s增加到0.006 kg/s时,体积蒸发通量增加了23.45%,但节能倍率降低了7.74%;当吹扫气温度从10℃增加到30℃时,体积蒸发通量减少了22.92%,但节能倍率升高了37.49%;以糖度为15°Brix的橙汁进行测试,当料液温度为38℃、吹扫气温度为26℃时,装置的体积蒸发通量可达219 kg/(m 3·h),节能倍率可达3.3。结论:热泵辅助无规填料表面蒸发装置浓缩热敏料液时具有常压下低温浓缩、能耗低等特点。

基于AMEsim的多金属结核扬矿泵管紧急排料机构超长液压油管参数设计

针对深海多金属结核扬矿泵管系统海上试验时可能存在的紧急排料需求,开展了海上试验系统紧急排料机构液压系统理论计算,并在AMEsim中进行了仿真试验,结果表明,AMEsim仿真软件对于该系统的可信度系数为0.86。基于AMEsim构建了500 m海上试验执行机构液压系统模型,仿真分析结果表明,液压系统中油管管径为16 mm,设定压力应不低于10.47 MPa,执行机构动作时间为6 s。研究结果可为紧急排料机构的设计提供依据。

竹材自动进出料软化压力罐的设计与制造

对竹材自动进出料软化压力罐进行了设计与制造。通过对竹材高温软化压力罐现状的分析,明确了自动进出料压力罐的设计要求,并确定了压力罐的内径、长度尺寸和结构要求。通过对软化处理后毛竹材的性能进行分析,获得了性能优异的自动进出料软化压力罐。产品的尺寸规格通常为内径200 mm、壁厚5 mm、长度3000 mm。

Research on feed-pulse collaborative control method in micro-electrical discharge machining

Reducing the short-circuit rate and increasing the effective discharge rate are important targets for improving the servo control effect of micro-electrical discharge machining(micro-EDM),as these two indicators are closely related to the machining efficiency and quality.In this study,a feed-pulse collaborative control(FPCC)method is proposed for micro-EDM based on two dimensions(space and time).In the spatial dimension,a feed control strategy with a discharge holding process is adopted.Meanwhile,in the time dimension,a forward-looking pulse control strategy is adopted,in which the pulse interval is adjusted based on a sequence analysis of feed commands and discharge states.Process experiments are carried out to determine the key parameters used in this method,including the discharge holding threshold and pulse interval adjustment value(T_(off_(adj))).The feed smoothness and discharge sufficiency analyses of the experimental results show that compared to the traditional double threshold average voltage method,the FPCC method reduces the number of long-distance retreats by 64%and improves the effective discharge time by 40%.

基于相似性原理的燃气电厂给水泵异常检测方法研究

设备运行监盘是燃气电厂重要的工作内容,提前识别设备运行中可能出现的异常并进行可靠预警,对保障电厂安全平稳运行至关重要。文章以燃气电厂给水泵为研究对象,基于大量运行历史数据,开发了一种基于相似性原理(SBM)和序列概率比检验(SPRT)的异常检测算法模型。通过建立当前观测向量与代表设备健康运行状态矩阵之间的相似度模型,得到各特征当前时刻预估值,并对不同时刻下各特征的模型预测残差进行均值检验,识别设备运行异常。结果表明,该预警方法可以使参数在偏离正常运行工况还未超过控制系统报警值之前,发出预警,弥补了原有工控系统固定值报警以及人工监盘导致的感知滞后、监视不到位的问题,为设备预测性维护提供技术支撑。

基于自动蓄/放热装置的多曲面聚光集热空气源热泵系统实验研究

为了实现北方农村地区清洁供暖,文章构建了基于自动蓄/放热装置和多曲面聚光集热器的空气源热泵供暖系统。实验研究表明:在相同供水温度下,随着蒸发器进口空气温度和太阳辐射强度的升高,热泵COP均逐渐升高。集热器及热泵联合运行时,蓄热装置可自动蓄热并对进入蒸发器的空气进行自动补热,空气温升为2~4℃,实验日系统集热量和制热量分别为2.29 MJ/m^(2),27.99 MJ/m^(2),系统能效比(SEER)为1.84,日平均太阳能贡献率为41.2%。空气源热泵单独运行时,实验日热泵制热量为8.75 MJ/m^(2),SEER为1.79。上述结果表明,文章构建的太阳能子系统可以自动调节系统的蓄热量及向蒸发器的补热量,提高了系统的能效比,降低了运行、维护难度,在农村地区具有一定的适应性。

空冷机组汽轮机主轴直接驱动给水泵的变工况运行仿真试验

汽轮机主轴直接驱动给水泵技术是一种全新的给水泵驱动方式,目前国内尚无成熟的运行经验。针对采用该技术的某350 MW直接空冷机组进行了系列变工况运行仿真试验。结果表明:对于配置1台100%容量主机泵和1台50%容量备用泵的机组,该技术完全能够满足在机组背压快速变化、负荷变化及给水泵故障等工况下给水流量的需求。

超超临界火电机组给水泵汽轮机20Cr13钢动叶片断裂原因

某超超临界机组在运行过程中,其给水泵汽轮机第4级20Cr13钢动叶片发生断裂事故。采用宏观观察、化学成分分析、金相检验、力学性能测试、扫描电镜及能谱分析等方法分析了叶片断裂的原因。结果表明:给水泵汽轮机部分动叶片装配不当,叶根与叶根槽装配间隙偏大,叶片明显松动;在转子长期高速转动过程中,叶片承受了较高水平的交变循环载荷,部分装配间隙大的动叶片叶根与叶根槽接触部位发生微动疲劳损伤,叶根周向边缘发生双向多源性疲劳开裂,裂纹逐步扩展,最终导致叶片断裂。

酒钢1#2#焦炉动力煤输送绿色智能化改造系统开发与实施

储运部动力煤料场改造项目是本部1#2#焦炉优化升级建设配套项目改造分项,主要从工艺上新增供料线、卸料线、3#~5#胶带机提速改造及配套环保控制系统,并对部分老料线进行了改造。工艺复杂、通信系统程序量大、参与联锁的设备较多是此项目实施的难点。

加氢装置进料泵润滑油压联锁停运原因分析及对策

进料泵是加氢装置的关键设备之一。某企业渣油加氢装置于2015年投产,先后发生2起因润滑油压力低低联锁导致进料泵紧急停运的生产异常事件。从润滑油系统着手,分析比较同类设备润滑油压联锁设计和配套油站的差异,通过油压联锁试验,认为油箱原始设计存在缺陷、油箱容量偏小、润滑油泵吸入口弯头积聚油气是润滑油备泵自启动后出口压力为0的主要原因。提出了增设排气设施、割除润滑油泵吸入口弯头以及将供油总管上自启动润滑油备泵信号测压点移至单向阀前等措施,解决了长期存在的润滑油备泵带气问题,有力保障了生产装置的安全平稳运行。

火电机组给水泵汽轮机振动跳闸的原因与防范措施

以某厂4#机组给水泵汽轮机突然出现1#轴承振动增大至保护值而导致机组跳闸为例,通过对该类生产事故的调查分析发现,转子联轴器不对中导致叠片式联轴器膜片断裂损坏,是给水泵汽轮机轴承振动增大的主要原因.为此,除及时采取相应的故障处理措施排除生产事故外,还根据此类故障产生的原因,提出相应的防范改进措施,以保障发电机组的安全运行.

高温高压工业锅炉给水泵机械密封运行研究

工业锅炉作为能源供应的核心组件,在现代工业中扮演着至关重要的角色。高效稳定的工业锅炉操作是确保工业过程顺利进行的关键因素之一。而在工业锅炉中,给水泵的功能无疑至关重要,它负责将给水输送至锅炉内,以维持高温高压环境下的稳定运行。工业锅炉的给水系统存在高温、高压以及容易汽化等问题经常会造成给水泵的机械密封失效,严重可导致重大事故发生。鉴于工业锅炉给水泵在生产中的重要性,结合具体DG型高温高压工业锅炉给水泵进行分析,讨论了现有的给水泵机械密封方法,并根据常见问题提出具体的提升策略,以为工业锅炉给水泵机械密封改进提供建议。