共查询到16条相似文献,搜索用时 203 毫秒
1.
2.
3.
随着国家标准GB/T22723-2008《天然气能量的测定》的发布,天然气能量计量的实施已经进入倒计时阶段。与此同时,该标准实际上也明确了在实施能量计量之后,商品天然气的发热量与其体积流量一样,都将属于法制计量范畴。根据《计量法》的规定,法制计量项目的计量器具(特别是计量基准和标准)、计量方法和测量不确定度必 相似文献
4.
《中国测试》2017,(Z1):24-28
随着能量计量方式不断被提出,间接法测量天然气热值成为能量计量过程中必不可少的步骤。在天然气场站中大多选用在线气相色谱仪对管道天然气组成进行持续分析检测,并通过GB/T 11062——2014规定的计算方法来间接测量天然气的发热量,这也是最快速可行的方法。以济南输气站在线气相色谱仪为研究对象,结合间接法测量天然气热值的过程,对过程中存在的每一个能对最终结果造成影响的因素进行分析探讨,并按照不确定度传递原则,对最终结果的不确定度进行评估,最终该文中天然气热值测量结果的相对扩展不确定度为0.88%(k=2),对应于热值的不确定度为0.34 MJ/m~3。 相似文献
5.
6.
7.
目前,国际天然气贸易大都采取能量计量的方式,而国内天然气则采取体积计量的方式,因计量条件不同,故交易双方之间存在诸多问题,因此积极地与国际接轨,推进能量计量工作迫在眉睫。而在国内开展天然气能量计量也存在一些问题,如热值测定理论不够完善,准确度评价方法研究不足和不确定度评价方法缺乏等。针对这些问题,采用现场实验的方式,研究并提出了天然气热值测定准确度判定的理论和实验方法,提出了在线气相色谱仪测量发热量的最大允许误差的评定方法;采用差异热值的标准气体对气相色谱仪进行标定,以此验证标准物质的准确度及仪器的测量能力。通过验证,标准物质的准确度及仪器的测量能力符合GB/T 18603《天然气计量系统技术要求》的要求,气相色谱测量天然气发热量的最大允许误差在0.5%左右,满足GB/T18603《天然气计量系统技术要求》0.5%~1.0%的MPE要求。 相似文献
8.
9.
天然气能量计量不确定度评定方法 总被引:1,自引:0,他引:1
在研究ISO 15112:2007、GB/T 22723—2008《天然气能量的测定》和其它相关标准的基础上,根据国内某长输管道天然气能量计量的实际情况,对天然气能量计量中的流量测量、温度测量、压力测量、压缩因子测量等参数不确定度进行了研究,提出了不确定度评定计算方法.并使用文中的方法对国内某长输管线上5个有代表性的实验站点的流量测量、温度测量等的不确定度进行了评定,验证了计算方法的正确性和合理性. 相似文献
10.
11.
Aaron Johnson Tom Kegel 《Journal of research of the National Institute of Standards and Technology》2004,109(3):345-369
This paper analyzes the uncertainty of a secondary flow measurement facility that calibrates a significant fraction of United States and foreign flow meters used for custody transfer of natural gas. The facility, owned by the Colorado Experimental Engineering Station Incorporated (CEESI), is located in Iowa. This facility measures flow with nine turbine meter standards, each of which is traceable to the NIST primary flow standard. The flow capacity of this facility ranges from 0.7 actual m3/s to 10.7 actual m3/s at nominal pressures of 7174 kPa and at ambient temperatures. Over this flow range the relative expanded flow uncertainty varies from 0.28 % to 0.30 % (depending on flow).CEESI Iowa: natural gas facility, CEESI Iowa uncertainty analysis, CEESI traceability to NIST, correlation coefficient, critical flow venturi uncertainty, traceability, turbine meter uncertainty analysis 相似文献
12.
13.
This paper presents the establishment and verification of a primary low-pressure gas flow standard with the capacity of 0.005
L/min to 24 L/min (at 23 °C and 101.325 kPa), newly established at National Institute of Metrology of Thailand (NIMT). This
facility is a mercury-sealed piston prover consisting of three precision-machined glass cylinders. Flow measurement can be
carried out manually or semi-automatically. The electronics were installed in a separate console to minimize their thermal
impact on the gas temperature. Special care was taken in designing the facility to ensure sound and representative gas pressure
and temperature measurement. The relative expanded uncertainty of mass flow measurement was evaluated to be less than 0.13%.
To verify the measurement capability and performance of the new facility, a bilateral comparison with the piston prover at
Center for Measurement Standards (CMS), Taiwan was conducted. The transfer standard used was a set of three critical flow
venturis with dedicated thermometers. Eight flow rates of dry air ranging from 42 mL/min to 14.5 L/ min at 0 °C and 101.325
kPa (0.055 g/min to 18.87 g/min) were tested. Comparison results showed that the E
n
values for the flow measurements at NIMT with reference to CMS were all well less than unity, demonstrating good agreement
between the two participants. 相似文献
14.
M. Jaeschke P. Schley R. Janssen–van Rosmalen 《International Journal of Thermophysics》2002,23(4):1013-1031
This paper gives a brief overview of existing energy measurement systems for natural gas and presents a novel correlative concept for determining the energy contained in a gas. In addition, it provides information on the development and application of a new fundamental reference equation of state. This equation greatly improves prediction of caloric properties and therefore allows optimization of the use of critical nozzles for metering natural gas flows of varying qualities. Laboratory tests of the new energy measurement system have shown that the target uncertainty of 0.2% for the calorific value is routinely reached. A feasibility study currently underway examines the possibility of building a reference calorimeter with an uncertainty of 0.05%. 相似文献
15.
16.
M. Jaeschke A. Schmücker A. Pramann P. Ulbig 《International Journal of Thermophysics》2007,28(1):220-244
Natural gas plays an important role for worldwide energy supply. For billing purposes precise metering of volume and superior
calorific value are very important. At present, only a few institutions worldwide are able to determine the superior calorific
value (SCV) of gases and their mixtures with an uncertainty of less than 0.2%. Calculations of SCV’s of natural gases using
the data of ISO 6976 provides a similar uncertainty as experimental approaches. For this reason a GERG (Groupe Européen de
Recherches Gazières) project was initiated to develop a new reference calorimeter for determining the SCV of flammable gases
(natural gases), based on the principle of Rossini for a combustion calorimeter. The purpose of such a reference calorimeter
is to determine the SCV of pure gases and gas mixtures with an uncertainty of less than 0.05%. The overall uncertainty budget
for the SCV is mainly influenced by the mass determination and temperature measurement. An automated weighing and calibration
device is used to measure the mass of the combusted gas with an experimental uncertainty of approx. 0.015%. In addition to
the experiment, the flow and temperature field in the calorimeter were simulated. These simulations help to reduce each of
the combined uncertainties for the combustion and calibration experiment resulting from the temperature measurement. The determination
of the adiabatic temperature rise is performed analytically. The assumptions made by early investigators were carefully reconsidered
for the first time. The analysis of the temperature–time curves considers (a) the method of evaluation, (b) the interval length
of the main period, (c) the location of the heat release during the calibration experiment, and (d) the temperature sensor
location. 相似文献