30000m~3/h空分设备氩气回收系统的投用和改造

南钢制氧厂30000 m3/h空分设备的1000 m3低温液氩贮槽配备了氩气回收系统,但启用后造成了1000 m3低温液氩贮槽被污染和精氩塔氮含量偏高的事故,检修并改造管路系统后氩气回收系统运行正常。介绍氩气回收系统的流程和管路检修、改造方案。     

回收液氩贮槽中蒸发氩气效益好

<正>随着液氩分装不断发展,一般用液氩泵分装充瓶,电耗、成本大大降低,但液氩贮槽内蒸发的氩气不能用液氩泵压缩,只有白白放掉。我们浙江绍兴钢铁总厂制氧厂,利用旧氧气压缩机改为无润滑高纯氮气压缩机专利技术改造成的压缩机,压缩氩气,回收放空氩气,取得较好的经济效益。     

采用压缩机分装液氩的实践

<正>从1994年开始,我们对液氩分装进行分析,一般用液氧泵作为分装主机。但液氧泵价格高;充装时要有较多的氩气钢瓶;气化液体回收在低温贮槽内,若液体少了,气化气不能凝结成液体,导致压力增高,只有放掉,但损耗大。为此,我们考虑采用原来压     

发展中的无锡成功气体有限公司

<正>1999年1月15日无锡成功气体有限公司两个100m~3立式液氧与液氩贮槽,在公司充灌站前广场上屹立而起,与已在运行的三个低温贮槽(50m~3液氧贮槽、50m~3液氩贮槽、15m~3液氮贮槽)构成雄伟壮观的一排低温液体贮槽群。     

真空粉末绝热低温液体贮槽的焊接

奥氏体不锈钢的低温力学性能优良,很适合于制造低温贮槽和装置,空分行业中用于贮存液氮、液氧、液氩等的真空粉末绝热低温液体贮槽就是由奥氏体不锈钢制成。本文详细介绍了这类贮槽的焊接技术。图2表1。     

液氩槽车充装技术:高压充装 尾气回收

低温液体充装前,槽车、联接软管的预冷及充装中贮槽必须的升压、低温液体的复热蒸发等,均不可避免地造成产品液氩的汽化损失。文章从生产实际中总结出“低压充装、尾气放空”、“高压充装”、“高压充装,尾气回收”三种充装方法,并一一对比。向同行推荐一种快速、低消耗的低温液氩槽车充装技术——“高压充装,尾气回收”。该方法同样适用于其它低温液体充装。图2表3参1。     

低温液体供气系统

对低温液体（液氮、液氩、液氧）供气系统的工作原理、贮存运输优越性、低温液体贮槽、气化器以及供气系统做了介绍。低温液体贮运具有效率高、供气质量好、压力稳定、成本低、使用安全以及洪气快速简便等优点。适用于电子工业、机械加工行业大量使用高纯氮气、氩气做保护气体。液氧经气化后由供气系统供给无任何污染的纯氧气代替工业氧气钢瓶为医院病员提供干净的呼吸氧气。     

30000m~3/h空分设备提高氩气产量的措施

针对武钢引进两套30000m3/h空分设备氩气生产现状,挖潜增氩,具体做法为:充分利用精馏潜力,改变空分设备有关设计参数;提高操作水平,减少变负荷对氩气生产的影响;回收液氩充槽车汽化放空的氩气;精氩塔不合格液氩的排放与回收。改进后,全年可增创效益1090万元。图2。     

液氩冷量回收技术

文章主要介绍液氩冷量回收装置的原理、流程及操作要点。将原来散失在大气中的冷量进行回收 ,用来液化氧气和液氩贮罐中保温不好而汽化的氩气 ,以增加液体产量 ,具有可观的经济效益。     

采用薄膜分离—低温分离混合流程从空气中提取氩

氩是生产氧的空分设备的一种副产品,从空分设备得到的粗氩纯度大约为94％～97％,含氧3％～6％,含氮0.05％～1％。空分设备可生产含氧量较低的粗氩,但原料空气中氩的提取率就会陡然下降。一般将粗氩进一步净化得到高纯度氩。净化第一步是将氢加入粗氩中,并通过催化装置,粗氩中的氧与氢反应生成水,然后将水份除掉,剩下的粗氩气体进入低温精馏设备,除去氮和多余的氢。粗氩中的含氧量及最终产品的允许含氧量决定了这种流程的耗氢量相当大,氢成本占了净化过程总成本中相当可观的一部分,而且,在某种情况下,由于空分设备安装位     

钢铁企业用空分装置的调峰、氧气终压及适用流程的探讨

目前对空分装置的要求出现了两个较明显的变化 :一是要求产液量大、氩产量高 ;二是要求氧气终压有所降低。对第二个变化进行了一些分析 ,提出了一种能同时满足这两种要求、又省投资和运行费用的流程组合 ,并作了比较和分析。介绍了球罐与低温液体贮槽及“球罐 +液氧调峰”的能力及优缺点 ,对我国钢铁企业适用空分流程进行探讨。最后提出了六点结论。     

Thermomechanical response of LNG concrete tank to cryogenic temperatures

The reinforced concrete tanks for liquefied natural gas storage, which have many advantages over steel tanks (high resistance to cryogenic temperatures and thermal shock, fatigue and buckling, fire resistance, etc.), are analyzed. Since the main drawback of concrete tanks is their poor resistance to tensile stresses, in order to investigate the thermally induced tensile stresses, a numerical model of a transient thermal analysis is presented for the evaluation of thermomechanical response of concrete tank to the cryogenic temperature, taking into account the temperature dependence of the thermophysical properties of the concrete tank thermal conductivity and specific heat.     

我国大型低温液体贮槽发展简况

近年来,随着现代化工业与科学技术的飞速发展,大型低温液体贮槽也得到相应的发展。我国先后设计并生产了容积３００ｍ＾３、４００ｍ＾３、５００ｍ＾３、１０００ｍ＾３的双层壳平底拱形顶常压粉末绝热的低温液体贮槽。文中简要介绍贮槽的结构特点、底部绝热、制造安装及相关的一些问题。     

BEPC-Ⅱ低温系统的氦气净化技术

氦气净化技术是国家大科学工程北京正负电子对撞机重大改造(BEPC-Ⅱ)中低温系统的关键技术之一.在充分调研国内外大型低温系统氦气净化技术的基础上,结合自身情况,创造性提出氦气储罐内部处理及真空置换方案,一次性充入氦气,将储罐内氦气不纯度控制在40 vpm之内,同时辅之以80 K外置低温吸附器对氦气储罐内以及冷箱和超导设备端的氦气进行净化.高效而又经济的解决了BEPC-Ⅱ低温系统中的氦气纯度问题,成功地进行了制冷机的验收测试和超导设备的调试及运行.     

大型低温液体贮存站贮罐设计选型论证(续)

运用热力学第一定律对低温液体在贮存、运输转注过程中的热力学特性进行了分析,定量分析、计算了低温液体节流过程的节流汽化率值,提出了减少节流过程所形成的汽化率的有效途径;论证了在大型低温液体贮存站贮罐设计选型时,应根据不同的低温液体液源、液体品质和操作工况等条件进行设计选型;论证了除合理地选择正确的低温液体贮罐结构形式外,还应高度重视低温液体贮罐的安全泄放设计,以确保低温液体贮存站的安全性能、使用性能和技术经济性能均处于最佳状态。     

高真空多层绝热低温液体运输半挂车的开发研制

简述高真空多层绝热低温液体运输半挂车的基本结构、绝热特性 ,并阐述了该车在低温液体运输的应用前景。     

用于低温贮箱的铝合金-硬质聚氨酯泡沫夹芯共底设计与分析

采用铝合金面板-硬质聚氨酯泡沫夹芯的复合式夹层构型,设计了一种用于低温火箭推进剂贮箱的共底结构,其具有轻量化、易于制造、承载/隔热一体化的特点。通过数值模拟手段,对该共底的隔热效果、结构稳定性及热力耦合问题进行分析。结果表明,该共底满足低温液氢/液氧贮箱隔热要求,在0.342 MPa压差下不失稳,单箱打压低于0.5 MPa时材料不失效。此结构的设计分析可为新型低温贮箱共底的设计提供技术支持。      

Fatigue crack propagation behavior in AISI 304 steel welded joints for cold‐stretched liquefied natural gas (LNG) storage tank at cryogenic temperatures

AISI304 steel welded joints are used in cold‐stretched liquefied natural gas (LNG) storage tanks used for storing and transporting of liquefied gases. Compared with a conventional liquefied natural gas storage tank, a cold‐stretched liquefied natural gas storage tank has many advantages such as reduced thickness, light weight, low cost and low energy consumption. However, liquefied natural gas storage tanks can be subjected to alternative loads at cryogenic temperatures; thus, it is important to investigate the fatigue crack propagation behavior in AISI 304 steel welded joints at cryogenic temperatures. Specimens were machined from a cold‐stretched liquefied natural gas storage tank with a welding structure. The crack length was determined using compliance method and confirmed by examination with traveling microscope. Fatigue crack propagation rates were evaluated at various stress ratios and temperatures. The fatigue crack growth rate of all specimens a little appears the effect of stress ratio, but it has a great influence at a cryogenic temperature. The fatigue crack growth rate of longitudinal welded joint is the fastest at room and cryogenic temperature. Fracture mechanism in the specimen is examined using a scanning electron microscope.     

Simulation of LOX reorientation using magnetic positive positioning

A combination of both experimental and computational simulation results have recently provided strong evidence that magnetic positioning may be a feasible alternative technology for managing cryogenic propellants onboard spacecraft. One prerequisite in the assessment of magnetic propellant management is the ability of predicting propellant reorientation in full-scale propellant tanks. A computational simulation is used to model magnetically induced liquid oxygen (LOX) flows in reduced gravity. Simulations of magnetic positive positioning of LOX are presented and the influence of the magnetic field and background acceleration on reorientation timing is explored. A dimensionless reorientation time is sought to compliment the magnetic Bond number and Bond number as an additional predictive correlating parameter for scaling this process. Evidence is provided that supports the continued use of these correlating parameters to predict the magnetic fields required to reorient cryogenic propellants in full-scale spacecraft tanks. Further, this study supports the conclusion that magnetic positive positioning appears to be a viable emerging technology for cryogenic propellant management systems that merits further computational investigation and space-based experimentation to establish the technology base required for future spacecraft design.     

Experimental study on cryogenic moisture uptake in polyurethane foam insulation material

Rigid foam is widely used to insulate cryogenic tanks, in particular for space launch vehicles due to its lightweight, mechanical strength and thermal-insulating performance. Up to now, little information is available on the intrusion of moisture into the material under cryogenic conditions, which will bring substantial additional weight for the space vehicles at lift-off. A cryogenic moisture uptake apparatus has been designed and fabricated to measure the amount of water uptake into the polyurethane foam. One side of the specimen is exposed to an environment with high humidity and ambient temperature, while the other with cryogenic temperature at approximately 78 K. A total of 16 specimens were tested for up to 24 h to explore the effects of the surface thermal protection layer, the foam thickness, exposed time, the butt joints, and the material density on water uptake of the foam. The results are constructive for the applications of the foam to the cryogenic insulation system in space launch vehicles.