High-rangeability ultrasonic gas flowmeter for monitoring flare gas

A transit-time ultrasonic gas flowmeter for high-rangeability requirements, such as those encountered in flare-gas flow-metering, is presented. The concept of ray rescue angle for the orientation of the ultrasonic transducers in single-beam transit-time ultrasonic flowmeters is introduced to overcome the problem of ultrasonic beam drift in high-velocity flows. To overcome problems associated with noise at high velocities, a chirp signal is used. To preserve the accuracy of the meter at low velocities near zero flow, a combination of chirp and continuous-wave signals is used to interrogate the flow. Overall system performance is presented, based on results from extensive wind-tunnel tests.     

HP6890系列气相色谱仪分析炼厂气

本文介绍两种分析炼厂气的方法:一种是传统的由几个步骤组成的方法;另一种用HP6890系列气相色谱仪分析,这种方法能一次完成分析,快速而准确。此文还讨论了在分析过程中应用注意的几个问题。     

纳米ZnO气敏元件对H2的测定研究

以采用物理热蒸发法制备的纯ZnO纳米线以及Ag掺杂ZnO纳米线为气敏基料制备成旁热式气敏元件,用静态配气法对不同浓度的H2进行气敏性能测试。利用测试结果,绘制元件灵敏度与所测气体浓度的关系曲线,并对此曲线进行了线性拟合。结果表明,Ag掺杂纳米ZnO元件与纯纳米ZnO元件相比会明显提高对H2的灵敏度,两类元件的气敏性能与所测气体浓度呈现相同的变化规律。用拟合方程计算出的气体浓度值与实际检测值间吻合较好,误差小于10%。因此,可以利用这两类元件及其拟合直线对H2气体浓度进行测定。     

GTL synthesis gas generation membrane for monetizing stranded gas

This feature article provides details of the development of a high-performance membrane for use in gas-to-liquids (GTL) synthesis gas generation for monetizing stranded gas assets.     

用pVTt法气体流量装置检定流量计

为满足0.2级及0.5级高准确度气体流量计量值溯源需求,建立大标准容积的pVTt法气体流量标准装置,使用组合阀门换向法对气体流量计进行动态检定,利用附加质量修正消除阀门换向系统时间引起的误差,分析检定过程中关键参数如压力、温度变化规律,获得使测量不确定度最优化的检定流程。通过分析测量过程中标准容器、温度、压力、附加质量等关键量的影响,进行测量不确定度评定,得到使用pVTt法气体流量标准装置检定气体流量计的测量不确定度为Ur=0.11%(k=2),证明使用pVTt法气体流量标准装置检定0.2级及0.5级气体流量计的可行性及合理性。     

膜吸收技术及其在脱除酸性气体中的应用研究

膜基气体吸收是膜技术与气体吸收技术相结合的新型杂化膜过程，与传统的气流接触吸收相比有诸多优点，通过介绍膜基气体吸收技术的分离机理及其在脱除酸性气体中的应用特点，展示了膜基气体吸收技术在化学工业中的广阔应用前景。     

酒钢氧气、氮气、氩气管网系统改造分析

随着钢铁企业产能的不断提高,氧气、氮气、氩气管网系统潜在的风险更加突出。分析制氧站区内外氧气、氮气、氩气管网系统存在的故障点和风险性,提出改造方案,使气体供应更稳定、安全,减小对后续生产的影响。     

锅炉房燃气缓冲管段计算与调压设备选择

燃气调压器在出口负荷突变为零时,调压器出口压力会在很短时间内大幅升高,从而引起调压器的安全保护装置的启动;通过设置缓冲管段,可有效控制调压器出口压力的变化,增加调压器运行的稳定性.     

MEMS气敏传感器

随着MEMS技术的飞速发展，各种MEMS器件和系统相继问世，MEMS气敏传感器是其中之一。本文重点介绍了7种MEMS气敏传感器。     

Semiconductor gas sensors

Abstract

The technology associated with the use of semiconductors in monitoring the composition of the atmosphere has been advancing rapidly in recent years. The twin demands of remote process control and concern for the environment have produced requirements for sensing different gases in a wide range of applications. In this paper the authors review the state of the art of semiconductor gas sensor development and anticipate the directions in which future progress is likely to be made.

MST/221