空分制氩工艺

本文介绍了空分制氩工艺,分析了氩馏分在精馏塔内的分布情况、抽取位置、对主塔的影响等,并论述了怎样在保证主塔稳定的前提下制取合格的氩产品,以及发生氮塞时的事故处理。     

空分装置粗氩塔氩固化的分析与处理

介绍KDON-7000/4000空分装置在一次短期停车再启动过程中,粗氩冷凝器产生的氩固化现象,分析氩固化产生的原因,并在保证主塔稳定运行的情况下,采取相应措施,解决了氩固化问题。     

空分精馏系统最佳氩馏分位置的确定

指出在同时生产高纯度的氢、氮及粗氩产品，并带粗氩塔的空气分离双级精馏系统中，双级精馏塔的上塔存在最佳抽氩馏分位置，并介绍其确定方法。     

69000 Nm3·h-1空分装置变负荷对系统的影响

鹤壁煤化工空分装置利用动力厂提供的8.8 MPa的高压蒸汽驱动汽轮机空气压缩机压缩环境空气,带压的工艺气经预冷、纯化系统及膨胀机制冷后进入精馏塔,采用低温精馏的方法分离出氧、氮、氩,并为后系统提供合格的高压氧气、高中压氮气、仪表气,并生产副产品液氧、液氮、液氩。阐述了69 000 Nm3·h-1内压缩空分装置在实际运行中的变负荷原则、操作顺序及操作速度,最后结合空分原理分析了变负荷时对主塔及氩系统的影响。     

内压缩流程空分的换热与精馏研究

分析和讨论了内压缩空分设备的氧氮两组分、氧氮氩三组分及氧氩两组分和氮氩两组分的相平衡,精馏部分的上塔、下塔、粗氩塔、精氩塔的精馏以及高压主换热器、低压主换热器、过冷器及主冷凝蒸发器等换热设备。希望能促进空气分离设备在理论方面的发展。     

XKAr-6-1型提氩装置产量质量影响因素分析

分析影响提氩装置产量质量的主要因素为：主塔工况稳定性、粗氩纯度、吸附器使用周期等，针对这些因素提出优化操作要点，使氩气产量质量超过设计水平。     

60000m~3/h空分设备新增提氩装置优化设计

介绍3套不带氩(带增效塔)60000m~3/h等级空分设备的制氩系统改造方案及取得的效果,叙述了制氩系统改造方案优化过程中解决的问题,分析了3套空分设备共用1套新增提氩装置的可行性,为以后类似流程空分设备新增提氩装置提供借鉴。     

空分精氩塔氮塞的分析与处理

简单叙述了精氩塔的工作原理和工艺流程图,着重阐述了精氩塔在运行过程中发生氮塞的原因及现象,并对此给出了相应的解决方法。     

氩系统不停车加温的方法和效果

1概述 我厂第2套KDON-14000／28000空分装置，由中国开封空分公司独立设计制造，为分子筛常温吸附、增压透平膨胀机、规整填料上塔和无氢制氩流程。1999年12月投用，2000年4月调试出氩，同年8月通过72h考核。该装置氩系统流程见图1。     

带氮塔的62500m~3/h空分流程优势、存在问题及处理

介绍了国内首套带氮塔的62 500 m3/h空分装置的四层主冷凝蒸发器、高低温膨胀机及氧氮后备系统的流程特点及优势,分析了该套空分装置投运过程中出现的氮塔负荷低、上塔液悬、系统液氮泵密封气压力波动、后备液氮泵汽蚀、氩系统投运过程氩馏分高等问题,通过相应的技术改造,确保了装置的安全达产。     

液氩沿纳米级微通道流动的模拟:外力的影响

Liquid argon flow along a nanochannel is studied using molecular dynamics (MD) simulation in this work. Large-scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) is used as the MD simulator. The effects of reduced forces at 0.5, 1.0 and 2.0 on argon flow on system energy in the form of system potential energy, pressure and velocity profile are described. Output in the form of three-dimensional visualization of the system at steady-state condition using Visual Molecular Dynamics (VMD) is pro-vided to describe the dynamics of the argon atoms. The equilibrium state is reached after 16000 time steps. The effects on system energy, pressure and velocity profile due to reduced force of 2.0 (F2) are clearly distinguishable from the other two lower forces where sufficiently high net force along the direction of the nanochannel for F2 renders the attractive and repulsive forces between the argon atoms virtually non-existent. A reduced force of 0.5 (F0.5) provides liquid argon flow that approaches Poiseuille (laminar) flow as clearly shown by the n-shaped average velocity profile. The extension of the present MD model to a more practical application affords scientists and engineers a good option for simulation of other nanofluidic dynamics processes.     

Influence of firing conditions and production methods on fracture strength of titanium-based metal ceramic crowns

Objectives: This study evaluated the effect of argon atmosphere compared with vacuum during porcelain firing on the fracture strength of crowns made of porcelain and electron beam melted (EBM) Ti-6Al-4 V, cast commercially pure titanium or milled commercially pure titanium. Methods: Sixty crown copings of c. p. titanium, Ti-6Al-4 V alloy and porcelain were fabricated using three production techniques. The copings were fired either under vacuum or in an argon gas atmosphere. Specimens were subdivided into groups of cast c. p. titanium, milled c. p. titanium and EBM Ti-6Al-4 V which were further subdivided according to firing modes employing either vacuum or argon gas. The 60 specimens were subjected to cyclic preloading and thermocycling, and were then individually loaded until interface fractured. Differences between the group mean values were calculated using the one-way ANOVA and Tukey’s range test. Two fractured samples from each group were cut with a diamond blade and examined using SEM and EDS for visualization and chemical composition analysis of the fractured interface. Results: The highest mean fracture strength values, though not significant, were recorded for the groups fired in argon atmosphere, and the lowest mean fracture strength values were recorded for the groups fired in vacuum, with one exception. Comparing the two main groups of firing atmosphere, no significant difference could be documented. SEM and EDS analysis indicated clear differences in composition and structure between the groups included in the study. Conclusions: Firing in argon atmosphere does not significantly improve the fracture strength of porcelain bonded to titanium.     

长寿型透气砖的生产和性能改进

透气砖是钢包底吹氩精炼作业的主要功能元件，其自身的耐冲刷、耐侵蚀和供气性能等严重地制约着钢水精炼效果。本文通过选择优质原材料、微粉和适当的外加剂来提高透气砖的使用性能，从而使其性能提高，使用寿命延长。试验结果表明：合理的微粉级配，特别是2种不同粒度的微粉进行配合、恰当的原料组成是保证透气砖浇注体致密性、高耐侵蚀冲刷性及长寿命的重要条件。适当地减少Cr2O3的含量和降低高温强度以及适当低的膨胀剂的加入量可以提高透气砖的吹开率，使吹开率由原来的90％提高到99％。     

钢包底吹氩自动控制系统

介绍钢包吹氩原理及钢包底吹氩工艺和装置,采用S7-300PLC作为控制器,用模糊控制与PCM控制相结合,实现精确智能的流量控制。比较自动底吹氩装置与传统底吹氩方式的优缺点,并对自动底吹氩装置进行优化。     

远程等离子体处理对聚四氟乙烯表面的功能化改性

采用远程氩等离子体对聚四氟乙烯(PTFE)膜进行了表面改性研究,通过接触角测定仪、扫描电子显微镜(SEM)和X射线光电子能谱仪(XPS)等手段,分析研究了改性后材料表面结构、性能的变化。结果表明:PTFE表面经远程氩等离子体处理后,表面微观形态和表面化学成分均发生了变化,且处理效果优于常规氩等离子体。远程氩等离子体可以在一定程度上抑制电子、离子的刻蚀作用,强化自由基反应,使材料表面获得更好的改性效果。经远程氩等离子体短时间(100s)处理后,PTFE表面的F/C比例从1.97降至1.44,O/C比例从0.015增至0.086;表面的水接触角从108°减小到53°;表面自由能从22.4×10-5N·cm-1增加至52.3×10-5N·cm-1。     

Separation of Argon and Oxygen by Adsorption on a Titanosilicate Molecular Sieve

Abstract

A titanosilicate molecular sieve adsorbent, Ba-RPZ-3, was synthesized and tested for its use in the separation of O₂+Ar mixtures at room temperature. A clean resolution of both gases was achieved in pulse chromatographic experiments using a standard column (0.25″ OD, 3.5 grams of adsorbent). In another experiment, using a column containing 30 grams of adsorbent and a continuous O₂+Ar feed at 10 cm³/min, argon breakthrough was detected more than 5 minutes before the oxygen breakthrough, and the separation was sufficiently sensitive to achieve quantitative separation of mixtures with low argon content (5% Ar). Equilibrium adsorption isotherms and isosteric heats of adsorption for oxygen and argon were found to be almost identical at room temperature. The thermodynamic selectivity was found to be mildly in favor of oxygen (～1.1–1.2). However, the adsorption of oxygen was observed to be much faster than argon, indicating that the separation of the O₂+Ar mixtures was based on the sieving properties of the adsorbent and the difference in sizes of O₂ molecules and Ar atoms. This indicates that a suitably-oriented oxygen is physically smaller than argon, despite the fact that many references assume that oxygen is larger than argon.     

LJ势氩系统分子动力学模拟中截断半径的选择

近年来在分子动力学方法研究LJ(Lennard-Jones)势氩系统时,越来越多的计算建议采用4.5?甚至更大的截断半径(?为氩原子直径)。本工作研究了不同截断半径对等温等压NPT系综氩系统熔沸点相图的影响,分析了不同截断半径下在氩系统的熔点及液相区域不同热力学状态点的径向分布函数和速度自相关函数。结果表明,以熔点为基准,在距离其相同液态温区分率的热力学温度点能获得相同的热力学性质,2.5σ的截断半径在模拟的准确性和计算性能上均能满足模拟的要求,本工作为液氩模拟中截断半径的选择指明了一个新的思考方向。     

全自动氩弧焊技术在 OC反应器蛇管制作上的应用

通过对全自动氩弧焊设备及工艺参数的选择方法的介绍,说明全自动氩弧焊技术是提高焊接质量和效率的最佳方法之一。     

自整定模糊PID控制器在钢包精炼炉底吹氩控制系统中的应用

介绍安钢第一炼轧厂钢包精炼炉底吹氩流量控制系统的组成、系统模型的建立及参数设计,分析了自整定PID控制器的应用效果,并在PLC中实现模糊化和模糊推理,实现一种简单易用的自适应流量模糊PID控制系统。