天然气中稀有气体同位素测试结果的比对与讨论

根据天然气稀有气体同位素地球化学论著中已发表的数据 ,作者将中国和日本的分析项目数与数据质量分别进行了对比 ,认为中国的天然气中稀有气体同位素分析项目相对较少 ,但数据是准确、可靠的 ,具有国际可比性。对分析项目少的原因 ,从技术上进行了讨论和分析 ,指出国内目前主机都缺少四极质谱和低温泵等外围设备 ,是造成分析项目少的主要原因 ,需同行们关注与努力     

天然气中稀有气体浓度与同位素比值联测技术及应用

研制了天然气中稀有气体纯化富集的前处理装置,并与稀有气体同位素质谱仪联用,构建了气体样品中He、Ne、Ar、Kr、Xe浓度和同位素比值联测的分析系统,通过1次进样可得到5种稀有气体组分浓度和同位素比值的共计23个数据。稀有气体纯化效果可达99.9%,质谱分析He、Ne、Ar、Kr浓度的相对标准偏差小于10%,同位素比值分析的标准偏差普遍小于5%。将该方法用于分析塔里木盆地天然气样品,得到了丰富的地质地球化学信息,通过稀有气体分布特征进一步明确了塔河和雅克拉气田区域构造活动的差异,以及二者气源岩特性的不同。     

色谱分析仪在天然气计量中的应用

天然气各组分含量是天然气计量的基础参数,天然气气质的准确分析对天然气计量至关重要。气相色谱法是测量天然气组成最常用的方法,气相色谱法具有选择性高、分离效率高、灵敏度高、分析速度快等特点。本文介绍了Pro GC-2000天然气色谱仪在绍兴天然气门站输气管道处的成功应用,通过在线色谱仪实时取样分析,得到天然气组成、密度、发热量、沃泊指数、压缩因子等物性参数,并将结果及时输入流量计算机中,实现对天然气流量和能量的及时修正,确保天然气计量准确可靠。本文阐述了色谱分析原理、结果分析方法、天然气计量系统组成和工作原理等。     

避开钐干扰的钕同位素质谱分析

本文讨论避开钐(Sm)干扰的钕(Nd)同位素测量程序及~(143)Nd/~(144)Nd正规化比值和~(144)Nd/含量的计算,给出了按本方法获得的钕参考标准试样的测量结果,还讨论了与钕同位素稀释分析有关的测量数据的误差传递。     

电感耦合等离子体质谱测量硒的研究进展

近年来,准确测量生物、食品、环境、地质等样品中的硒元素含量、同位素组成及其各种形态受到越来越多的关注。随着质谱技术的发展,电感耦合等离子体质谱(ICP-MS)技术成为硒的各种特性量研究和测量的重要手段,使其在生命科学、环境地球化学、生物、营养等研究中有着广泛的应用前景。本文综述了ICP-MS法应用于硒同位素比值,元素总量以及多种形态测量技术方面的最新研究进展。     

天然气中Ar同位素对比测定及数据分析

近年实验室研制了高精度、超高真空的净化系统与VG5400质谱计在线连接,实现了天然气中He、Ar同位素的在线测量。在测量过程中为杜绝进样过程的氩同位素质量分馏效应,本次工作采用了“分段静态平衡移样”法,提高了天然气中氩同位素测量的精度。应国家重大基础研究“973”天然气项目的要求和安排,对过去测量过氩同位素的一批钢瓶样(51个)进行了对比测量分析。研究结果表明,过去测量过程中存在空气本底的污染和同位素分馏效应,但两次测量结果有73%的数据在估算源岩年代公式的数据误差范围之内,本实验室认为原测量数据能够满足源岩地质年代段的粗略估算要求。另外,对比研究结果还表明,过去认为同一样品40Ar/36Ar测量结果较高值是正确的这一说法是不全面的。     

天然气中氮同位素组成的气相色谱-质谱分析

氮气是天然气中常见的组分之一,天然气中氮的主要来源于大气氮、生物作用有关的氮、与岩浆作用有关的氮和与地幔有关的氮.不同来源的氮具有不同的氮同位素组成[1,2].以往天然气的氮同位素组成样品制备采用燃烧法或气相色谱制备法[3,4]. 用以上方法取得了一些氮同位素的数据,但是由于大多数天然气中氮气的含量很低,用这种方法难度大,在样品制备和转移过程中很容易受到空气的污染,氮的研究尚处于资料积累阶段[5].     

X射线荧光法快速测定硅铝合金中的硅含量

本文介绍采用X射线荧光法测定硅铝合金中硅含量的方法及相关条件,并对测量结果精度进行分析。本方法具有样品前期处理简便、干扰因素小,且快速、准确等特点。     

X射线荧光法快速测定蒙脱石(固态)中的铝含量

本文介绍采用X射线荧光法测定蒙脱石中铝含量的方法及相关条件,并对测量结果精度进行分析。本方法具有样品前期处理简单、干扰因素小,且快速、准确等特点。     

原油溶解气中稀有气体同位素分析

国内稀有气体同位素分析技术主要应用于分析天然气和固体矿物样品。原油样品采集易受空气污染,并且挥发性有机组分严重影响分析结果。本实验利用压力差设计了一种顺压采样器,以排除空气;采用真空－超声波脱气;通过两级纯化系统,实现溶解气活性组分的完全去除,降低对超高真空仪器Noblesse的污染。结果表明：原油脱气效率达99．5％以上;同位素分析的相对标准偏差＜6．10％。顺压采样器及两级纯化系统的提出,实现了原油稀有气体分析。     

丙烯中微量烃类杂质的色谱分析方法研究

建立了气相色谱仪测定丙烯中21种烃类杂质含量的定量分析方法。实验采用配备FID检测器的Agilent6890N型气相色谱仪,选用50m×0．53mm×15μm的HP—PLOTAL2O3“S”型毛细管色谱柱。利用动态气体稀释仪稀释标准气,测定并绘制外标曲线（浓度小于1×10^-6（v／v））。结果表明此分析方法具有良好的准确度和精密度,各组分的相对标准偏差（RSD）均小于2％,加标回收率为81％～114％,最低检出限小于1×10^-6（体积分数）,从而为丙烯中烃类杂质含量的测定提供了一种高效、准确、快速的分析方法。     

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气体组分和气体同位素分析

本文报道了采用质谱法测量气体组分和Ｎ、Ａｒ同位素的一些结果，供研究与应用参考。     

Uncertainty analysis of energy measurements in natural gas transmission networks

The value of natural gas depends on the energy obtainable from its combustion. Despite this, natural gas measurement and billing are normally performed using volume measurements subsequently converted into base conditions. Thus, to correctly achieve network balancing and accurate billings, both civil and industrial natural gas consumptions should be measured in energy. Unfortunately, energy measurements for natural gas are actually possible only in an indirect way by means of complex measurement chains with a flow-meter, a volume conversion device and a gas chromatograph or gas analyzer. Moreover, for technical and economic reasons, gas quality is often considered as constant and known despite the unavoidable variations due to the mixing of gases from different origins and type (i.e. importations, national productions, liquefied, biogas).In this paper the authors present the results of a detailed metrological experimental analysis of the typical energy measurement plants installed in natural gas networks. Modern networks are characterized by a wide variety of flow-rate measurement principles, constructive technologies and plant configurations. Therefore, flow regimes, thermodynamic conditions and chemical properties of the gas play a crucial role in determining metrological performance of natural gas energy measurements and uncertainties can become critical for inaccurate billing and unaccounted for gas.     

变温加热和神经网络方法检测混合气体

研究了采用单只气敏元件通过变温加热和神经网络信息处理,对乙醇和醋酸混合气体的识别和浓度检测的方法。根据气敏元件的灵敏度随加热温度发生改变的特点,在气敏元件上施加锯齿波加热电压,测量了周期变温条件下25种不同浓度乙醇和醋酸混合气体的归一化电导—温度曲线。然后,采用由64个输入节点和2个输出节点组成的BP网络,以及Levenberg-Marquardt算法对测量数据进行处理。结果说明,该气体分析系统对乙醇和醋酸混合气体有较好的分类识别效果。     

Studying the proportional discharge dynamics in mixtures of various gases using a chamber with preliminary electron multiplication

By using a chamber with preliminary multiplication of ionization electrons and extraction of the electron component of signals, the proportional discharge dynamics was studied in various gas mixtures, including mixtures of noble gases with gases, whose ionization potential is below the excitation energy of noble gas atoms (Penning mixtures). It was revealed that the main signals with durations of several microseconds, which are determined by the collection of electrons from primary avalanches, have “tails” of secondary avalanches with durations of up to tens of microseconds with a total charge comparable or exceeding the charge in the primary avalanches.     

Characterization of Hazardous Gases Using an Infrared Hyperspectral Imaging System

A rapid algorithm for passive remote sensing of gases with an infrared hyperspectral imaging system is reported that includes approximate and precise measurements. In the former, the spectral region of interest for the analytes is identified. In the latter, fitting calculations in the selected range and for spectral similarity measurements are employed to remove erroneous pixels from the approximate measurement to better characterize the gas sample. The results verify that the algorithm reduced the time for qualitative and quantitative determination of gases compared with conventional approaches.     

Prediction of non-equilibrium kinetics of fuel-rich kerosene/LOX combustion in gas generator

Gas generator is the device to produce high enthalpy gases needed to drive turbo-pump system in liquid rocket engine. And, the combustion temperature in gas generator should be controlled below around 1,000K to avoid any possible thermal damages to turbine blade by using either fuel rich combustion or oxidizer rich combustion. Thus, non-equilibrium chemical reaction dominates in fuel-rich combustion of gas generator. Meanwhile, kerosene is a compounded fuel with various types of hydrocarbon elements and difficult to model the chemical kinetics. This study focuses on the prediction of the non-equilibrium reaction of fuel rich kerosene/LOX combustion with detailed kinetics developed by Dagaut using PSR (Perfectly Stirred Reactor) assumption. In Dagaut’s surrogate model for kerosene, chemical kinetics of kerosene consists of 1,592 reaction steps with 207 chemical species. Also, droplet evaporation time is taken into account in the PSR calculation by changing the residence time of droplet in the gas generator. Frenklach’s soot model was implemented along with detailed kinetics to calculate the gas properties of fuel rich combustion efflux. The results could provide very reliable and accurate numbers in the prediction of combustion gas temperature, species fraction and material properties.     

标准混合气配制装置的研究

本文提出了一种在阻塞流动状态下精确控制纯气体流过喷咀的时间，进行高精度配制标准混合气的方法；并研制了相应智能标准气发生装置。该装置配气精度高、轻便、可靠、操作方便，可用于现场配制各种标准混合气。