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《压力容器》2019,(9):47-52
夹套是一种典型的压力换热设备,广泛应用在反应釜、混合器、气化炉中。夹套内部冷却流体自身带压,夹套壁又同时承受较高的温度梯度,操作不当时极易发生失效。针对某厂电煅炉水冷夹套冷却系统中,水冷夹套外壁面出现烧穿、熔融,并导致炉体损伤破坏的失效原因进行了热耦合数值模拟分析。结果表明,在事故工况0. 025 MPa的进水压力下,冷却水无法完全充满夹套,夹套内部液相上方存在一个气相空间,导致夹套器壁局部出现过热现象,器壁温度高达1 379. 25℃,造成夹套外壁过热损伤乃至烧透。通过进一步分析,在设计压力为0. 1 MPa下,夹套具有较好的冷却效果,器壁温度低于557℃,冷却效果可以保证设备安全运行。 相似文献
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本文阐述了带夹套压力容器在设计过程中应对内筒、夹套及未被夹套包围的设备零部件设计压力给予区别对待,并结合实例进行了说明。 相似文献
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分馏釜强度试验失稳事故分析 总被引:1,自引:0,他引:1
某单位制造的分馏釜在夹套强度试验时,由于超压引起内筒体失稳,以致夹套与内筒体间的角焊缝开裂。设备价值十几万元,这次事故使该厂蒙受了重大的经济损失。 相似文献
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曹向阳 《机械工人(热加工)》1998,(5):14-14
某厂生产的反应釜夹套壁厚为12mm的16MnR钢板,设备法兰为20MnMo锻件,内胆为1Cr18Ni9Ti,筒体为22mm的16MnR。整个反应釜有11条重要焊缝,分别由埋弧焊和手工电弧焊焊接而成。 反应釜的工作温度为250℃,釜体工作压力为4.9MPa,夹套工作压力为1.5MPa,介质为易燃易爆物质。该反应釜在安装试运行时发现焊缝产生裂纹,虽未造成事故,但如不查清裂纹成因,采取有效措施根治隐患,将危及安全生产。 一、裂纹的分布 裂纹位于相对的两支座上方夹套与设备法兰的手 相似文献
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在压力容器设计中,除了受内压容器外,还有不少承受外压的容器。例如,真空贮罐、减压蒸馏塔、带有夹套加热或冷却的反应釜,当夹套中介质的压力高于容器内介质的压力时,也构成了外压容器。对于外压容器,在既定直径和材料的前提下,增加圆筒厚度δ或减小圆筒计算长度L... 相似文献
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反应釜下封头应力腐蚀断裂事故分析和预防措施 总被引:1,自引:0,他引:1
1 设备概况某化工厂的一台用于生产医药中间体的 30 0 0 1的反应釜如图 1所示 ,内筒直径为DN16 0 0 ,夹套直径为DN180 0 ,主要技术参数见表 1。工作开始时 ,夹套通蒸汽加热 ,釜内达到反应所需温度 ,反表 1项目内筒夹套工作压力 (MPa) 0 6 0 3工作温度 (℃ ) 6 0 15 0工作介质易燃、低毒介质水蒸汽、冷却水主要受压元件材质 0Cr18Ni9Q2 35 -A容积 (m3 ) 3应开始 ,该反应为放热反应。反应到一定程度 ,夹套通冷却水冷却 ,此为间隙式操作 ,一般反应时间为 10小时左右。反应釜投入使用后 ,发现夹套传热不理想 ,改用反应釜内置盘… 相似文献
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浮动堆长期处于海洋环境中,其安全壳设备闸门处于海洋环境下浮动堆的随机运动状态中,同时外部的冲击事故也会对其结构造成严重破坏,由设备闸门与安全壳一起形成第三层屏蔽,包容放射性物质,是安全壳压力边界的重要组成部分,也是安全壳压力边界较薄弱的环节,因此设备闸门密封性能对于浮动堆的核安全至关重要。结合水动力学和瞬态动力学,分析事故工况下设备闸门密封面上下法兰的变形,提取最大变形处相对位移值,构建二维密封面模型模拟事故工况下密封面变形情况,并基于二参数的Mooney-Rivlin本构模型描述密封圈材料的应变能函数,分析密封圈总体变形、应力分布、接触应力分布,结合试验数据判定海洋环境下浮动堆设备闸门事故工况下密封性能分析。 相似文献
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Ihn Nanigung Seung Ha Jeong Dae Hee Lee Taek Sang Choi 《Journal of Mechanical Science and Technology》2005,19(1):51-60
The KSNP+ RV closure head drop analysis was carried out to assess the reactor core coolability in case of the RV closure head drop
accident during the refueling operation. The analysis consists of a number of different RV head drop scenarios as the postulated
accident events during refueling that include a concentric head drop case and three different cases of laterally offset head
drop cases. The analysis was initiated due to the adoption of the IHA (Integrated Head Assembly) in the KSNP+ reactor design, which increases the weight of the RV closure head assembly. Four different analysis models were developed
that correspond to the RV head drop analysis scenarios. An in-house dynamic analysis code was used for the RV head drop analysis.
The entire reactor internals and fuel assemblies are modeled by using lumped masses and spring elements. Because of the extreme
load exerted by RV head drop, most members experience stresses that are beyond the elastic limits. A separate elastic—plastic
analysis for some members was carried out and the resulting load-deflection curve was used as the stiffness of the element.
The effect of water above the reactor vessel in the refueling pool was ignored for the conservative estimation of the analysis.
The analysis shows that the concentric head drop is the most severe case of loading condition. It also reveals that the local
deformation of some reactor internals and the fuel assemblies is occurred; however the primary membrane stresses are within
the bound of allowable stress limits. Consequently the reactor core remains in coolable state. 相似文献
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The retention of a molten pool vessel cooled by internal vessel reflooding and/or external vessel reactor cavity flooding
has been considered as one of severe accident management strategies. The present numerical study investigates the effect of
both internal and external vessel mixed cooling on an internally heated molten pool. The molten pool is confined in a hemispherical
vessel with reference to the thermal behavior of the vessel wall. In this study, our numerical model used a scaled-down reactor
vessel of a KSNP (Korea Standard Nuclear Power) reactor design of 1000 MWe (a Pressurized Water Reactor with a large and dry
containment). Well-known temperature-dependent boiling heat transfer curves are applied to the internal and external vessel
cooling boundaries. Radiative heat transfer has been considered in the case of dry internal vessel boundary condition. Computational
results show that the external cooling vessel boundary conditions have better effectiveness than internal vessel cooling in
the retention of the melt pool vessel failure. 相似文献
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过卷是简体在卷制过程中最不希望看到的情况。一旦发生简体过卷事故,其返修需要栅较大的代价。结合国内某反应堆简体卷板的实际情况,从理论分析和实际操作两方面,介绍了超大型简体过卷后采用制造厂现有设备以较低的成本对简体进行返修的过程。 相似文献
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设计了基于并行探针驱动的扫描刻蚀加工系统,用于微纳米尺度的刻蚀加工.研究了系统的核心器件—微小等离子体反应器的电学特性和发射光谱特性,以了解反应器中产生的反应等离子体性能的变化规律.基于微机电系统(MEMS)加工工艺制备了中间带有倒金字塔形状微型空腔的金属-绝缘体-金属3层结构的微小等离子体反应器.搭建了可测量等离子体伏安特性和发射光谱特性的实验系统,对放电气体为SF6,工作气压在5~12 kPa,直流驱动模式下的微小等离子体反应器的电学和光谱特性进行了测试.实验结果表明,放电电流随着放电电压的增加而近似线性递增,放电电流由5 kPa时的2.1~2.82 μA递增到12 kPa时的3.6~4.2 μA,表明所产生的微小等离子体处于异常辉光放电模态.当器件特征尺寸由150 μm减小至30 μm时,微小等离子体发射光谱中氟原子特征谱线(703.7 nm)峰值增大了约56%,表明微小等离子体的浓度随尺度缩小而增强.实验结果表明,设计的微小等离子体反应器基本满足扫描刻蚀加工所需的高浓度等离子体源的性能要求. 相似文献