柴油加氢装置隔膜式换热器管束泄漏分析

加氢装置高压换热器管程介质由于操作温度逐渐降低,氯化铵在管束中析出结垢,易造成垢下腐蚀,单纯依靠管束材质升级防腐存在弊端。以柴油加氢装置高压隔膜式换热器管束泄漏为例,确定其泄漏原因,并从设备和工艺操作角度进行分析,提出延长管束使用周期的建议。     

加氢裂化在用反应流出物空冷器管束的检验

加氢装置反应流出物空冷器(以下简称：REAC)结构特殊、失效机理复杂，某国产化REAC的管束曾发生泄漏爆管事故。对某企业其余REAC带翅片碳钢管束采用远场涡流、内窥镜、超声波等检测方法进行了检验，本文提出了有关在用REAC的检验方法。     

加压塔再沸器失效分析与整改方案

从设计和操作原因对加压塔再沸器管束断裂失效进行分析,并提出改造方案,对换热器的设计使用有一定的借鉴作用。     

REAC管束腐蚀失效的远场涡流检测研究

提出了碳钢管束失效的远场涡流检测技术,主要包括远场涡流检测原理、试样制备、检测灵敏度选择和检测仪器及操作条件等。应用于加氢反应流出物空冷器碳钢管束腐蚀失效的现场检测,该方法能快速、有效地实现带翅片碳钢管束的远场无损检测。     

换热器管束腐蚀失效原因及防护措施研究

为解决换热器管束在实际应用中腐蚀严重导致设备使用性能降低的问题,在对换热器管束腐蚀及其防护机理研究的基础上,通过制定检测方案对已腐蚀的换热器管束的外观和SEM、EDS进行检测,充分掌握换热器管束发生腐蚀的主要原因;基于上述检测结果,通过在换热器管束表面电镀Ni-P合金和将软化处理后的地下水更换为循环冷却水的方式达到防腐目的。     

尿素装置中换热器的防震结构

将通常构成管壳式换热器壳侧流体通路及支撑管束的折流板改用折流杆——即折流杆式换热器,普遍认为是对消除壳侧流体脉动引起机械振动的一种有效措施。本文介绍我国从国外引进的尿素装置中管壳式冷凝器壳侧采用的几种管束支撑结构——格栅支持圈,是“折流杆”换热器在工程中的具体应用。由于条件限制,只限结构尺寸介绍及防震方面的阐述,目的为研究管壳换热器壳侧震动提供一些具体资料,文章也简要介绍格栅支持圈管束的组装方法。     

黄铜换热管的腐蚀破坏及预防措施

对黄铜管换热器管束在氨渗试验过程中发生应力腐蚀，导致铜管破裂的原因进行了分析，改进了施工方案，并提出了黄铜管换热器制造过程中对管束进行耐压试验时的注意事项。     

管壳式换热器试压工装

阐述了钩圈浮头式换热器、浮头管板廉作法兰浮头式换热器、浮头式换热器管束和管板非兼作法兰U形管式换热器管束的试压工装设计思路，并提出了详细的试压方案。     

基于预应力技术立式夹套换热器结构应力分析

废热换热器在工业中应用广泛,但较高的热应力容易使结构失效破坏。因此,通常从锅炉结构和制造技术方面考虑,以降低热应力对结构的影响。介绍了一种以并排焊接的扁圆管兼做管板的结构特点,并利用换热器预应力技术来缓解该换热器主要构件(扁圆管、换热管和夹套管)之间的变形约束。以换热管与夹套管之间的热膨胀差为基础,利用ANSYS有限元软件分析了6种预变形量对扁圆管结构应力分布和管束拉脱应力的影响。结果表明,7~9.45 mm范围的预拉伸量可以有效地降低温差热应力并缓解管束的轴向拉脱应力。     

特殊结构管壳式换热器的设计与制造

对几种典型换热器的总体结构进行了介绍,并对管板、管接头以及管束支撑等关键结构进行了分析。从而表明了中国一重在大型、高压换热设备设计、制造领域的优势。     

Manufacturing and temperature measurements of a sodium heat pipe

A high-temperature sodium stainless steel heat pipe was fabricated and its performance has been investigated. The working fluid was sodium and it was sealed inside a straight tube container made of stainless steel. The amount of sodium occupied approximately 20% of the total volume of the heat pipe and its weight was 65.7gram. The length of a stainless steel container is 1002mm and its outside diameter is 25.4mm. Performance tests were carried out in a room air condition under a free convective environment and the measured temperatures are presented. The start-up behavior of the heat pipe from a frozen state was investigated for various heat input values between 600W and 1205W. In steady state, axial temperature distributions of a heat pipe were measured and its heat transfer rates were estimated in the range of vapor temperature from 500°C to 630°C. It is found that there are small temperature differences in the vapor core along the axial direction of a sodium heat pipe for the high operating temperatures. But for the range of low operating temperatures there are large temperature drops along the vapor core region of a sodium heat pipe, because a small vapor pressure drop makes a large temperature drop. The transition temperature was reached more rapidly in the cases of high heat input rate for the sodium heat pipe.     

油气管线在役焊接烧穿的影响因素及研究现状

压力管道在役焊接修复时间短,速度快,对管道正常运行影响小,有巨大的经济效益和广阔的应用前景.但是在役焊接时可能发生烧穿,有很大危险性.本文总结了对于在役焊接烧穿研究的意义,分析了管道的壁厚,管内压力,焊接的线能量等因素对于烧穿的影响.总结了国内外对于烧穿研究的成果及不足之处,展望了在役焊接烧穿的研究前景.     

大型薄壁筒节类零件防变形加工方法

针对大型薄壁筒节类零件由于直径大,壁厚薄导致刚度较低,在切削力、切削热、残余应力和夹紧力等因素影响下,易发生加工变形,不易控制加工精度,加工效率低的问题。以反应堆压力容器的通风罩支承为例,介绍一种大型薄壁筒节类零件防变形加工方法。     

微型热管在台式电脑中的应用设计

本文根据热管导热速度很快的工作特征,在具体情况下热管可制作成可大可小的、可长可短的、可自由弯曲的结构。提出了在计算机核心部件上应用微型热管散热,将热量引出到专用风道内集中散热。机箱可制作成较封闭的结构的设计方案,从而解决了计算机中用传统风扇散热效果差,与外界对流又带来灰尘沉集在主板上,对主板带来安全隐患的问题。     

复合中空热管传热性能研究

为了解决工业中的大量低品质烟气余热的回收利用和烟气酸露点腐蚀导致设备容易失效的工程问题,提出了一种复合中空热管传热元件,介绍了其结构及工作原理;对其内部传热机理进行了分析,并对其启动特性、等温性能和传热性能进行了试验研究。研究结果表明:复合中空热管在外管壁温度30℃时,加热时间2 min之内就能正常快速启动工作;在自然空气对流冷却条件下,具有较好的等温特性;复合中空热管的传热系数随着冷却水雷诺数的增加而增加;在加热蒸汽温度低于125℃的低温蒸汽加热条件下,当冷却水的雷诺数为6650时,复合中空热管的传热系数为1350W/(m2.℃)。试验研究结果为复合中空热管换热器的工程应用提供了基础。     

18—8型奥氏体不锈钢导管焊接防腐工艺研究

分析了18—8型不锈钢焊缝产生晶间腐蚀的机理,提出了在焊缝中添加Ti、Nb等合金元素,改善焊接时的加热与冷却条件以及采用焊后热处理等防晶间腐蚀的措施。     

Examining the Experience of Revealing Delayed Deformation Corrosion Cracking

The problem of skipping iron-oxide–filled damages in the welding junctions between the collector and Dn1200 branch pipe of the PGV-1000 steam generator in a VVÉR-1000 reactor facility is considered. The mechanism of crack nucleation and development is described. A hypothesis that cracks filled with corrosion deposits exhibit minimum reflectivity has been proposed and confirmed. Results of theoretical research into transmission and reflection of ultrasonic waves in the presence of a thin layer of corrosion products surrounded by pearlitic steel are provided. The reflectances of longitudinal and transverse waves from corrosion damages have been calculated and proved the viability of the hypothesis.     

扩口管路密封失效引起的平管嘴大径外圈锈蚀故障分析

针对某氧气浓缩器进气口扩口管路连接处平管嘴的锈蚀故障，采用宏观、微观分析手段，结合EDS能谱分析确定了平管嘴已发生深入金属基体的锈蚀，且锈蚀产物主要为Fe₂O₃。通过逻辑推导分析腐蚀介质的可能来源，通过有限元建模，分析实际装配中最常见的带偏角装配工况下扩口管密封面上的Mises应力和CPRESS接触压力分布，得出平管嘴锈蚀故障的原因为：因该处管路连接需周期性反复拆装，拆装操作容易出现不同轴偏角装配情况，造成导管扩口内锥面接触不均匀和异常变形，从而破坏了密封面完整性，使导管内部与平管嘴/外套螺母间的间隙之间形成连通通道，冷凝湿气或腐蚀介质可通过这些通道逐渐泄漏并聚集到间隙处，最终导致缝隙腐蚀发生。     

超薄微热管的研究现状及发展趋势

快速增加的系统发热已经成为当代先进微电子芯片系统研发和应用中的一项重大技术挑战。热管以其高导热率、高冷却能力、高稳定性和长寿命等优点在高热流密度元件的散热技术领域得到广泛应用。但是,随着电子产品不断朝着高性能化与轻薄化的方向发展,传统圆柱型微热管或普通压扁型热管已难以应用于紧凑、轻薄型的电子设备散热,体积更小、质量更轻、厚度更薄的超薄微热管已成为目前热管技术的重要发展方向和研究热点。详细介绍了超薄微热管的类型及应用,重点综述了目前国内外关于超薄微热管在成形工艺及吸液芯结构等方面的研究进展情况,分析讨论了其在电子器件散热中的发展所存在的问题,并进行科学预测与展望。     

Assessment of the sulfide corrosion fatigue strength for a multi-pass welded A106 Gr B steel pipe below the low SSCC limit

In the area of heavy construction, welding processes are vital in the production and maintenance of pipelines and power plants. Welding processes happen to produce residual stresses and change the metal structure as a result of the large nonlinear thermal loading that is created by a moving heat source. The fusion welding process generates formidable welding residual stresses and metallurgical change, which increase the crack driving force and reduce the resistance to the brittle fracture as well as the environmental fracture. This is a serious problem with many alloys as well as the A106 Gr B steel pipe. This pipe that is used in petrochemical and heavy chemical plants either degrades due to corrosive environments, e.g., chlorides and sulfides, and/or become damaged during service due to the various corrosion damage mechanisms. Thus, in this study, after numerically and experimentally analyzing the welding residual stress of a multi-pass welded A106 Gr B steel pipe, the sulfide stress corrosion cracking (SSCC) characteristics were assessed in a 3.5 wt.% NaCl solution that was saturated with H₂S gas at room temperature on the basis of NACE TM 0177-90. The specimens used are of two kinds: un-notched and notched. Then, the sulfide corrosion fatigue (SCF) strength for the un-notched specimen was assessed below the low SSCC limit that was previously obtained from the SSCC tests for the notched specimen. From the results, in terms of the SSCC and SCF, all the specimens failed at the heat-affected zone, where a high welding residual stress is distributed. It was found that the low SSCC limit of un-notched specimens (σ_{SSCCun-notched}) was 46% (230 MPa) of the ultimate tensile strength (σ_U=502 MPa) of a multi-pass welded A106 Gr B steel pipe, and the notched specimens (σ_SSCCnotched) had 40% (200 MPa) of the ultimate tensile strength. Thus, it was determined that σ_{SSCCun-notched} was 13% lower than σ_SSCCnotched. Further, the sulfide corrosion fatigue limit (σ_{SCFun-notched}) was 32% (160 MPa) of the ultimate tensile strength of welded specimens. This σ_{SCF un-notched} was 20% lower than σ_SSCCnotched.