低温绝热压力容器失效因素与检验常见问题概述

本文介绍了低温绝热压力容器在使用过程中潜在的失效因素,并以广东省为例,简述了现阶段检验的实际情况。从容器本身出发,结合检验标准和规程,马氏体组织引发的封头直边端开裂、轻量化引起的材料夹层与气、液相接管连接的角焊缝泄漏、夹层真空度失效是引发真空绝热压力容器失效的主要原因,然后列举了常见的低温绝热压力容器在定期检验中的问题并进行简要分析,探讨了低温绝热压力容器的安全合理使用以及科学检验问题,对真空绝热压力容器的检验技术优化有一定的指导作用。     

真空绝热低温移动式压力容器检验问题探讨

探讨了真空绝热低温移动式压力容器的定义及其作用,阐述了压力容器定期检验的意义,最后详细分析了真空绝热低温移动式压力容器定期检验中的常见问题,不同缺陷的产生原因及处理措施,以期为真空绝热低温移动式压力容器的检验提供一定的参考。     

红外热成像技术在低温压力容器检验中的应用

红外热成像技术用于低温压力容器绝热性能辅助检验,可以迅速探测出大型低温容器漏冷部位及漏冷程度;红外成像技术用于大批量的低温绝热气瓶检验可以迅速找出表面温度异常偏低的气瓶,为进一步静态蒸发率测量提供依据,可大大提高低温压力容器的检验效率。     

红外热成像技术在低温绝热压力容器定期检验中的应用

随着低温技术的发展,液化气体在工业中的应用越来越广泛,由于承载液化气体的低温绝热压力容器结构的特殊性,直接检验方法较少,本文将介绍利用红外热成像技术对低温压力容器进行附加检测。     

蒸发率测定工艺

低温绝热压力容器静态蒸发率是一项非常重要的指标,确保静态蒸发率符合国家标准、规范要求是产品安全使用的前提,因此,认真做好静态蒸发率测量工作是十分重要的。本文论述了低温绝热压力容器静态蒸发率的测量方法、仪器设备、低温液体、测量条件、试验程序、数据处理。     

对低温设备的检测和标准体系的思考

分析了低温绝热容器的标准体系和低温容器性能检测的标准发展现状以及存在的主要问题;讨论了低温绝热容器的标准体系研究和低温容器性能检测的标准内容;根据压力容器、气瓶及压力管道的安全技术规范、标准的规定,提出了低温绝热容器的标准体系研究和《真空绝热设备低温性能试验方法》标准修订的建议。     

0Cr18Ni9不锈钢制低温绝热压力容器(内胆)埋弧焊工艺的试验

本文针对用于制造低温绝热压力容器内胆的10毫米以上0Cr18Ni9奥氏体不锈钢,采用埋弧焊工艺并保证其焊接接头的低温韧性方面进行试验研究,从而得到了符合标准要求的满意结果。     

低温绝热气瓶定期检验探讨

根据低温绝热气瓶结构特点,讨论了在低温绝热气瓶定期检验过程中,对低温绝热容器定期检验的关健项目、技术要点进行了具体分析,解决了在缺少具体检验标准、规范的情况下该类气瓶的定期检验问题.     

液化天然气罐车残气回收系统的开发研究

液化天然气(LNG)贮存、运输需要使用低温压力容器,如LNG罐车、LNG贮罐、LNG低温绝热气瓶等。这些特种设备在定期检验时,必须对罐体内残余气体进行置换。利用特定的回收装置,解决天然气残余气体直接排放对环境污染和作业安全问题,还可实现LNG罐车残余气体的有效回收利用,促进LNG罐车检验环节的安全节能环保,对于天然气的使用推广具有重大意义。     

低温压力容器及低温管道设计中应注意的问题

介绍了化肥行业中常用的低温压力容器、低温管道及其发生脆性破裂的条件与后果.针对化肥行业操作介质的特殊性并结合低温压力容器及低温管道发生破坏的特点,从设计温度、低温选材、结构设计、低温压力容器及低温管道的焊接、检验及使用等方面,分别介绍了其设计制造中应遵循的各项标准要求,并对低温压力容器及低温管道的使用提出了注意事项.     

Closed vessel combustion of propylene–air mixtures in the presence of exhaust gas

The pressure–time evolution during the deflagration of gaseous propylene–air mixtures in the presence of their own exhaust gas was experimentally investigated in a spherical vessel, over an extended range of equivalence ratios, at room temperature and various initial pressures within 0.3–1.0 bar. The characteristic parameters of closed vessel explosions (peak pressure, maximum rate of pressure rise, time necessary to reach the peak pressure, explosion index) are examined in connection with the fuel/oxygen ratio and with exhaust gas concentration. The measured flammability parameters together with the computed values of adiabatic explosion pressures and adiabatic flame temperatures are used to examine the inerting effect of exhaust gas.     

高压管道的氦泄漏试验

高压有毒流体,可燃流体的管道强度试验完毕后,依据规范的要求还必须进行泄露性试验。一般气体(空气)进行高压的管道气体泄漏试验,试验压力很高(一般为管道设计压力)非常危险。采用氦气作为试验介质,利用氦气检漏的高灵敏度在满足管系统高密封要求的同时,可大大降低泄漏试验压力,从而降低气压泄漏试验的危险性。     

甲烷/乙烷/空气预混火焰层流燃烧速度与火焰稳定性的数值研究(英文)

A numerical study on premixed methane/ethylene/air flames with various ethylene fractions and equivalence ratios was conducted at room temperature and atmospheric pressure. The effects of ethylene addition on laminar burning velocity, flame structure and flame stability under the condition of lean burning were investigated. The results show that the laminar burning velocity increases with ethylene fraction, especially at a large equivalence ratio. More ethylene addition gives rise to higher concentrations of H, O and OH radicals in the flame, which significantly promotes chemical reactions, and a linear correlation exists between the laminar burning velocity and the maximum H + OH concentration in the reaction zone. With the increase of ethylene fraction, the adiabatic flame temperature is raised, while the inner layer temperature becomes lower, contributing to the enhancement of combustion. Markstein length and Markstein number, representative of the flame stability, increase as more ethylene is added, indicating the tendency of flame stability to improve with ethylene addition.     

Experimental breakthrough curves determined under carefully controlled conditions for the adsorption of water vapour on alumina in adiabatic fixed beds

The adsorption on activated alumina of water vapour from an air stream is studied experimentally in an adiabatic fixed bed. The experimental set-up which provides accurate results is described. The influence of particle size, gas inlet concentration and temperature, linear gas velocity and bed length on concentration and temperature at bed outlet is investigated.     

Characterization of a Spray Drying System for Soymilk

Soymilk slurries were spray dried at various combinations of inlet air temperature (1255. 265, and 275°C), feed rate (0.38 and 0.57 Lpm), and atomizer speed (119,300 and 26,800 rpm). Monitored dryer parameters included dry and wet bulb temperaturea of ambient and exhaust air, drying chamber's inlet and outlet air temperatures, product and feed temperatures, velocity pressure at exhaust pipe, atomizer speed, and feed rate. Weather data was included in the analysis.

Collected data was used to estimate the state of the outlet air using psychrometrics and assuming adiabatic saturation. Equations to predict outlet and product temperatures were developed. Average thermal and eveporative efficiencies were 65.9 and 78.4%. respectively.     

Experimental Study of the Effect of High Back-Pressure on the Atomization of a Plain Jet Injector Under Coaxial Air Flow

An experimental study was carried out on the effect of high back-pressure on the spray characteristics of a plain jet injector in coaxial air flow. The back-pressures tested ranged from 100 to 1600 kPa, the velocity range of coaxially flowing air is 60–120 m/s. The working fluid was water. The injector hole diameter was 0.5 mm. The key feature of the experiment was to use a convergent-divergent nozzle connected to the atomization test chamber to maintain a high back-pressure in the chamber for atomization, and at the same time, to maintain a high-velocity air flow in the atomization region. Thus, it totally eliminated the air recirculation and droplet slow-settling problem in the commonly used pressurized vessel for high back-pressure atomization study. The results show that the Sauter mean diameter decreases monotonically with the increase of back pressure. At different air velocities, the effect of back pressure is different. The drop size distribution becomes more non-uniform slightly with increasing back pressure.     

Characterization of a Spray Drying System for Soymilk

ABSTRACT

Soymilk slurries were spray dried at various combinations of inlet air temperature (1255. 265, and 275°C), feed rate (0.38 and 0.57 Lpm), and atomizer speed (119,300 and 26,800 rpm). Monitored dryer parameters included dry and wet bulb temperaturea of ambient and exhaust air, drying chamber's inlet and outlet air temperatures, product and feed temperatures, velocity pressure at exhaust pipe, atomizer speed, and feed rate. Weather data was included in the analysis.

Collected data was used to estimate the state of the outlet air using psychrometrics and assuming adiabatic saturation. Equations to predict outlet and product temperatures were developed. Average thermal and eveporative efficiencies were 65.9 and 78.4%. respectively.     

传热模型对近临界工况CO2干气密封温压分布和稳态性能影响

干气密封流体膜与密封环间传热模型的合理选取对于准确求解密封温压分布和稳态性能至关重要。在CO₂近临界工况下,对比研究了密封环等温模型、绝热模型和共轭热传递模型对超临界CO₂干气密封端面温度、压力分布和开启力、泄漏率等稳态性能的影响,探讨了不同膜厚和转速条件下密封环等温模型和绝热模型的适用性,并基于共轭热传递模型研究了超临界CO₂和空气介质干气密封的温压分布和稳态性能差异。结果表明：以共轭热传递模型计算结果为基准,密封环等温模型假设适用于小膜厚低速流动工况,不过开启力偏低而泄漏率偏高,绝热模型假设适用于大膜厚高速流动工况;相较于空气介质干气密封,超临界CO₂干气密封在小膜厚下的温度分布和大膜厚下的压力分布基本接近,不过小膜厚下的温度更低,而在大膜厚下的压力更高。     

安全阀的开启压力和排放压力

介绍了安全阀的开启压力、排放压力与容器的工作压力、超压限度之间的关系;概括了超压限度的含义;指出采用最高允许工作压力作为超压起始压力的好处;提出气密性试验时,确定安全阀的开启压力应采取的方法。