DOCSLIB.ORG

Gas Interchangeability Testing Report

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Gas Interchangeability Testing Report Gas Interchangeability Testing Report Report Prepared for: Air Conditioning, Heating and Refrigeration Institute (AHRI) American Gas Association (A.G.A.) Association of Home Appliance Manufactures (AHAM) November 12, 2009 Date of Testing: February 2008 to April 2009 Program Objective The objective of this program was to investigate the operation of current designs of gas appliances when tested on four (4) different test gases representing possible gas mixtures that may be utilized in the United States in coming years. An advisory committee assembled by GAMA/AHRI and funded through various industry groups did the selection of gas composition. The four tests gases are presented as variations of their Wobbe Index (See the Appendix for a definition of Wobbe Index and its significance to appliance safety). The test program detailed in this report used 78 new (from stock), current production products and technologies. The program did not review products that are no longer produced, often referred to as legacy products, but rather focused on products currently in production and available to the consumer. A list of products by sample number only (manufacturers’ names omitted) is contained in the tables at the end of this report. Since the manufacturers supplied the samples without cost to the program, it is believed that anonymity of the test results is appropriate. The testing was conducted in a manner that represents what would be required for that product to meet the national safety and performance tests that are outlined in the various ANSI standards that govern the design, testing and production of those products. The appliance industry has 80+ years of evaluating products per the protocols outlined in these standards and believes that compliance with these test procedures insures the upmost safety to the consumer over the life of the product when installed, maintained and serviced per the manufacturer’s instructions. 2 Test Results Contained at the end of this report is a section labeled “Tables” and those tables contain the consolidated results in a condensed format along with a list of products submitted (by sample number only – manufacturers’ names withheld). The actual data for each sample tested has been provided to the sponsors and is not included herein due to its voluminous nature (approx. 430 pages) When reviewing the individual data sheets, please be advised that any value of CO (carbon monoxide) recorded as “1050” ppm means that the upper CO range of the instrument has been exceeded. It was not determined how far above 1050 ppm the actual value was, but the 1050 value was used for computational purposes in determining the minimum Air Free CO value that the results could have been, hence there are times where the CO values may be recorded (air free) on the data sheets as 1200, 2000, or more ppm. This is just the result of the mathematics of using 1050 ppm (maximum range of instrument) inserted into the air free calculation. Hence, the value is at least the number shown and may be much higher. Most likely any recorded CO air free value over 1100 ppm in the tables (attached) were generated because the measured CO was above 1050 ppm1. Some comments are in order when reviewing the consolidated data sheets (Tables). The individual sample data is presented with the lowest Wobbe Index gas (E) shown on the top row of data and the highest Wobbe Index gas (D) is shown as the fifth row of data, with test gas A in the middle or 3d row. The column labeled “Measured Input” is the measured input after any orifice or pressure change adjustments were made to bring the appliance within specifications as explained below. The column labeled “% of Data Plate Input” is the “Measured Input” column divided by the Data Plate Input. It is the data in the third row for gas “A” that should be within the specifications of tolerance detailed in the appropriate standard and as explained below in the test procedure write up. The column labeled “% of Test Gas A Input” reflects the change in input that occurred as the various Wobbe Index gas are used. By definition Test Gas “A” will always be 100.0%. In some cases the values do not follow the expected increase in input. This may have been human error in recording the results. But some of the reason may be that with some appliance designs, on a “hotter” gas such as gas D, there may have been conditions in which the actual heat on the manifold pipe or orifice increased to a point where the gas within the appliance 1 To make that determination: Multiply the stated value in the table by 12.2% and then divide the resultant value by the recorded CO2. This will give the reader the base CO value used for the calculation. 3 piping system became “hot”. Such a condition causes a density change in the gas before it travels through the flow control orifices, with the result that the measured gas input is reduced. It is expected that there will always be some density change of the gas in the appliance plumbing as the unit runs longer, and for this reason the appliance standards detail when the input rate is to be recorded. Ranges, water heaters and some boilers are very prone to rate reduction issues over elapsed time from a cold start. It was also noted that gas pressure regulator settings were changing by just changing the gas selection. This may be due to changes in mass flow through the regulators on products that are near the limit capacity of the regulator design. The word “Fail” is utilized in the test data as a way of stating the unit is not in compliance with the test criteria. This only means that the unit has exceeded the permissible values for some test parameter (CO, NOx, temperature, time for ignition, etc.) as detailed in the appropriate ANSI Z21 standard for that product type. It should not be taken in a negative context but only in the sense that most gas appliance testing has to meet a pass/fail criteria and this test program is utilizing these criteria to assist in the decision process. Of the 79 products tested that worked satisfactorily on Test Gas “A”, 40 units encountered some form of non-compliance on the remaining 4 test gases (B, C, D, & E). Or stated another way, within the scope of this limited testing, 39 units successfully met the established pass/fail criteria on all gas mixtures. Yet, even within those 39 units that were under the established CO generation limits, many exhibited increased CO generation as the Wobbe Index increased. 4 Test Protocols – General The following is to assist the reader in understanding some of the tests that were performed on the various test appliances and what some of the notes and comments in the presented data may be referring to. The discussions in this section are more generic in nature and specific deviations (by product type) from this general discussion can be found in each section detailing specific appliances. The actual tests procedures for conducting the tests noted below are found in the appropriate ANSI standard. For instance, gas furnaces are tested to ANSI Z21.47, boilers are tested per ANSI Z21.13, domestic water heaters to Z21.10.1, etc. See the Appendix for a complete list of the appropriate standards and their full titles. The normal test sequence for gas appliances as tested under this program was: 1. Rate the product to match the data plate input (Btu/Hr) in accordance with the procedures outlined in the appropriate ANSI standard for that appliance type using test gas A. In all cases that input had to be within either ±2% or ±5% depending upon product type. 2. Run ignition evaluation under a series of different adverse conditions to prove the reliability of safe ignition of the gas over the expected life of the product 3. Run Burner Operating Characteristics (B.O.C.) to prove the continued safe and satisfactory operation of the burners under a series of adverse conditions that proves the reliability of the product for the consumer 4. Evaluation of Carbon Monoxide (CO) emissions from the appliance under a series of conditions that proves the safety of the product under conditions of variability that are historically considered to provide safe operation of gas appliance over the life of the product. 5. Conduct NOx 2 emission testing for products subject to state or regional NOx regulations (furnaces, boilers, water heaters) or where specified, by the ANSI standard such as for vent free heaters. 6. On some furnaces, additional data was accumulated concerning metal heat exchanger temperatures, but the test procedure utilized does not represent the full, and very in depth, manner of looking at possible heat exchanger fatigue as detailed in the ANSI Z21.47 standard. The goal of this program was to look at trends rather than absolute values. A more in depth discussion of the appropriate test procedure is found in discussions below. Procedures for Placing the Appliance “On Rate” The appliance rate (input) was measured upon receipt of the appliance to verify that it was within the specifications detailed in the appropriate ANSI standard. As an example, 2 NOx=Nitrousoxide+Nitrogendioxide or NOx=NO+NO2 5 a furnace must be within ± 2% of the input as stated on the data plate as measured 15 minutes after starting the appliance from a cold start (room temperature). To achieve those tolerances a slight variance of the manifold pressure is permitted (± 0.3” w.c.) from the nominal manifold pressure that is also stated on the data plate.
Load more

Recommended publications
  • En Wobbe Index Control System in Gas Industry
    ~-4$ EN ! FROI05409 . ..+.. .“+_____________ WOBBE INDEX CONTROL SYSTEM IN GAS INDUSTRY PROCESSES SYSTEME DE CONTROLE DE L’INDEX DE WOBBE DU GAZ NATUREL DANS LES PROCESSUS INDUSTRIALS M. Cassibbaand M. Bertani SNAM, ltaly ABSTRACT Natural gassupplied toindustry forprocess utilisations originates from different sources and that can cause fluctuations in gas composition. Changing gas composition may lead to production problems in industry with sensitive thermal processes (particularly glass industry and thermal metal treatments), such as efficiency and product quality. An equipment suitable to control and adjust such variations has been developed. Experimental tests in laboratory were carried out in order to investigate the control system accuracy and reliability. In particular five different settings were tested: at a preset thermal input by adjusting the natural gas flow rate in respect to Wobbe Index variations; at a set furnace temperature and stack oxygen level with variable thermal input by monitoring the Wobbe Index value; at constant Wobbe Index value by adding air to natural gas; at constant thermal input and prefixed Wobbe Index value by adding air to natural gas and varying the air and gas mixture flow rate; gross calorific value control by adding air or LPG to natural gas. All the tested settings gave good results. This report illustrates these results and the main features of the control system. The control and regulation system was installed in two glass factories for field tests. RESUME Le gaz naturel utilise clans [es processus industrials provient de gisements a caracteristiques differences qui peuvent dormer lieu a des fluctuations clans la composition du gaz. Ces variations peuvent entralner des problemes clans certaines processus industrials tels que, en particulier, ceux du verre et du traitement des metaux.
    [Show full text]
  • 2002-00201-01-E.Pdf (Pdf)
    report no. 2/95 alternative fuels in the automotive market Prepared for the CONCAWE Automotive Emissions Management Group by its Technical Coordinator, R.C. Hutcheson Reproduction permitted with due acknowledgement Ó CONCAWE Brussels October 1995 I report no. 2/95 ABSTRACT A review of the advantages and disadvantages of alternative fuels for road transport has been conducted. Based on numerous literature sources and in-house data, CONCAWE concludes that: · Alternatives to conventional automotive transport fuels are unlikely to make a significant impact in the foreseeable future for either economic or environmental reasons. · Gaseous fuels have some advantages and some growth can be expected. More specifically, compressed natural gas (CNG) and liquefied petroleum gas (LPG) may be employed as an alternative to diesel fuel in urban fleet applications. · Bio-fuels remain marginal products and their use can only be justified if societal and/or agricultural policy outweigh market forces. · Methanol has a number of disadvantages in terms of its acute toxicity and the emissions of “air toxics”, notably formaldehyde. In addition, recent estimates suggest that methanol will remain uneconomic when compared with conventional fuels. KEYWORDS Gasoline, diesel fuel, natural gas, liquefied petroleum gas, CNG, LNG, Methanol, LPG, bio-fuels, ethanol, rape seed methyl ester, RSME, carbon dioxide, CO2, emissions. ACKNOWLEDGEMENTS This literature review is fully referenced (see Section 12). However, CONCAWE is grateful to the following for their permission to quote in detail from their publications: · SAE Paper No. 932778 ã1993 - reprinted with permission from the Society of Automotive Engineers, Inc. (15) · “Road vehicles - Efficiency and emissions” - Dr. Walter Ospelt, AVL LIST GmbH.
    [Show full text]
  • Gas Interchangeability Defined
    AGA Staff Paper: Technical Background and Issues of Gas Interchangeability Prepared for: Building Energy Codes and Standards Committee American Gas Association Prepared by: Ted A. Williams Director, Codes, Standards & Technical Support American Gas Association April 2006 Disclaimer This report was prepared by American Gas Association (AGA) Staff for the purpose of summarizing prior technical work, research, and technical application of gas interchangeability principles and practices. Neither AGA, its members, nor any person acting on behalf of these organizations: • Makes any warranty or representation with respect to the accuracy, completeness, or usefulness of the information contained in this report, or that the use of any information disclosed in this report may not infringe privately owned rights; or • Assumes any liability with respect to the use of, or for damages resulting from the use of, any information disclosed in this report. 2 Table of Contents 1. Gas Interchangeability Defined . 5. 1.1 The NGC+ Definition . 5. 1.2 Historical Definitions from the Gas Industry Literature . 6. 1.3 Implications of Gas Interchangeability as Defined . 6. 2. The Objectives of Gas Interchangeability Criteria . 7. 2.1 Anticipation and Avoidance of Adverse Combustion Behavior . 7. 2.2 Drivers for Gas Interchangeability Specifications in the U. S. 8. 2.3 Appliance Focus of Gas Interchangeability Studies and Specifications . 8. 2.4 Relevance of Historical Studies to Current End Uses . .11. 3. Combustion Issues in Classical and Contemporary Gas Interchangeability . 12. 3.1 General Combustion Issues . .12. 3.2 Combustion Failure Modes . .13. 3.2.1 Elevated Pollutant Generation . 13. 3.2.1.1 CO Production .
    [Show full text]
  • Interchangeability & Wobbe Index Used As Quality Parameter For
    INTERCHANGEABILITY AND WOBBE INDEX USED AS QUALITY PARAMETER FOR LIQUEFIED NATURAL GAS Rafael Rosal 1 and Sabrina Di Scipio 2. 1 Natural Gas Business Management Specialization. 2 Thermodynamics and Transfer Phenomena Department. Simón Bolívar University. Valle de Sartenejas, Baruta, Edo. Miranda. Venezuela. AP.89000. 1. Background The natural gas (NG) is projected like one of the most important energy sources in the future, due to its reduced contaminant effect and relatively low cost compared with liquid combustibles, like fuel oil or gasoline. Currently, Liquefied Natural Gas (LNG) is a common way to commercialize NG around the World. The main advantage of liquefaction process is the reduction by about 600 times of the total volume required for NG storage and transportation. Venezuela has big quantities of proven NG reserves (148 BCF). The country has to take profit of these reserves and monetize them in all possible ways [1]. Venezuela’s geographic location gives open access to most important oil markets, such as: Europe and USA. Historically, has sold to those regions the main part of its oil production and, few quantities are exported to Central America and Caribbean countries. In addition, Argentina, Brazil and, Chile have become in potential oil gas consumers. In order to verify the potential markets for the LNG that will be produced in Venezuela, it is important to analyze the influence of different gas compounds interchangeability on the final product; considering the specifications and gas compositions required by each country or region. A key interchangeability parameter is the Wobbe Index (WI). WI is used to compare the combustion energy output of different composition fuel gases in an appliance (fire, cooker, etc.), it changes with gas composition.
    [Show full text]
  • Methane Number
    Methane Number Gary Palmer Independent Consultant, Calgary, Canada Received October 24, 2017; Accepted October 25, 2017 Abstract: The Methane Number is a measure of the resistance of natural gas to detonation when it is burned as a motor fuel in an engine. Pure Methane is assigned a Methane Number of 100 and pure Hydrogen is assigned a Methane Number of zero. A natural gas having a Methane Number of 80 for example, would have the detonation properties of a mixture consisting of 80 vol% Methane and 20 vol% Hydrogen. The Methane Number concept is similar to the Octane Number for gasoline. Unlike gasoline however, there is not yet a universal standard for testing natural gas Methane Number as there is in the motor test for gasoline. Also, there is no universally accepted method for calculating the Methane Number based on the composition of natural gas. Keywords: Methane number, gas combustion 1 Methane Number The definition of Methane Number is simple if the gas consists only of the two components Methane and Hydrogen. But for hydrocarbon gas mixtures consisting not only of methane but also of Ethane and heavier, the definition is much more difficult and is the subject of much debate and controversy. There are various proposed methods of calculating Methane Number based on gas composition. Some are methods proposed by standards associations in Europe and some are proprietary methods proposed by engine manufacturers. 1.1 Standards Associations The following standards have been proposed to establish a universal method to relate gas composition to Methane Number but so far there has been no agreement on which method to use.
    [Show full text]
  • Current State and Prospects of Lng in the Unece Region
    STUDY: CURRENT STATE AND PROSPECTS OF LNG IN THE UNECE REGION CHAPTER 4: INTEROPERABILITY AND SAFETY TABLE OF CONTENTS: 1.- INTRODUCTION 2.- LNG QUALITY AND INTERCHANGEABILITY 2.1.- LNG Specifications 2.1.1.- General 2.1.2.- Gas Interchangeability Specifications in importing and exporting Countries 2.1.3.- Gas Quality Harmonization efforts: EASEE-gas 2.1.4.- Weathering/Aging issues in LNG Transport and Storage 2.2.- Impurity Specifications 2.2.1.- Origin of Impurity Specifications 2.2.2.- Review of Impurity Specifications in Europe and the rest of the World 2.2.3.- Proposed new Impurity Specifications 2.3.- Sampling, Analysis and Measurement of LNG Quality 2.3.1.- Sampling techniques 2.3.2.- Operational sampling for LNG Quality and Interchangeability 2.3.3.- Conclusion 2.4.- Quality adjustment at LNG Import Terminals and Liquefaction Plants 2.4.1.- Market specifications and LNG qualities 2.4.2.- NGL extraction at Liquefaction Plants and at LNG Import Terminals 2.4.3.- Heating Value Adjustment by LPG Injection in Import Terminals 2.5.- Impact of LNG Quality on Gas Turbine operation 2.5.1.- Gas Turbine design and fuel specifications 2.5.2.- Effect of Gas Quality on Gas Turbine operation 2.6.- Impact of LNG Quality on consumers: Appliance testing 2.6.1.- U.K. and Spain test work 2.6.2.- Marcogaz activity in gas Interchangeability in Europe 2.6.3.- U.S. Appliance Testing addressing gas Interchangeability 2.7.- Future Challenges 2.7.1.- The Near-Term Perspective 2.7.1.- The Long-Run Perspective 2.8.- Conclusions 1 3.- LNG FACILITIES COMPATIBILITY 3.1.- Executive Summary 3.2.- The characteristics of the LNG Facilities and the impact on the compatibility 3.2.1.- Introduction 3.2.2.- Terminal / LNG carrier compatibility in the Design Phase 3.2.3.- Storage Capacity 3.2.4.- Ship Shore Interface 3.2.5.- Conclusions 3.3.- Operational Safety of LNG Facilities and LNG Carriers 3.3.1.- Introduction 3.3.2.- Safety in operations 3.3.3.- Safety procedures 3.3.4.- Design codes and standards, 3.3.5.- Environmental issues 3.3.6.- Best practices.
    [Show full text]
  • Addressing Gas Turbine Fuel Flexibility
    GE Energy Addressing Gas Turbine Fuel Flexibility GER4601 (05/11) revB Robert Jones, Manager of Syngas Power Island Products Jeffrey Goldmeer, Product Marketing Manager Bruno Monetti, Product Marketing Manager Contents: Introduction. 1 Fuel classification. 1 GE operating experience . 3 Natural gas . 3 Alternative gaseous fuels. 4 High calorific value gases . 4 Medium and low calorific value (LCV) fuels . 5 Improving the LCV solution for the steel industry. 6 Refinery and coal IGCC. 7 Oils. 9 Bio-liquid fuels . 10 Summary and conclusion. 11 Appendix. 12 List of figures . 12 List of tables . 12 GE Energy | GER-4601 (05/2011) i ii Addressing Gas Turbine Fuel Flexibility Introduction than 50 years of fuel experience, GE has developed gas turbine technology that is proven and a more efficient alternative to other The global energy landscape is experiencing major changes as technologies, while burning the widest range of alternative gas and current economic issues evolve. There is worldwide pressure to liquid fuel. secure and make more gas and oil available to support global power needs. With constrained fuel sources and increasing Fuel classification environmental focus, the quest for higher efficiency and lower The potential fuels to be utilized on high efficiency gas turbines emissions targets in the context of security over fuel supplies are very large, and in this changing energy landscape, there is a seems straightforward. As Natural Gas Combined Cycle (NGCC) growing interest in turning to non-traditional fuels, capitalizing on plants provide very high efficiency, there will be increasing demand the experience gained during the past five decades. As continuous- for natural gas, which will continue the push for increased flow machines with robust designs and universal combustion availability of Liquefied Natural Gas (LNG).
    [Show full text]
  • Gas Turbine Fuel Flexibility: an Enabler for Regional Power Generation Jeffrey Goldmeer
    GE Power & Water Power-GEN International Gas Turbine Fuel Flexibility: An Enabler For Regional Power Generation Jeffrey Goldmeer © 2013, General Electric Company. Proprietary information. All rights reserved. GE Power & Water © General Electric Company, 2013. GE Proprietary Information - The information contained in this document is General Electric Company (GE) proprietary information. It is the property of GE and shall not be used, disclosed to others or reproduced without the express written consent of GE, including, but without limitation, it is not to be used in the creation. manufacture. development, or derivation of any repairs, modifications, spare parts, or configuration changes or to obtain government or regulatory approval to do so, if consent is given for reproduction in whole or in part, this notice and the notice set forth on each page of this document shall appear in any such reproduction in whole or in part. The information contained in this document may also be controlled by the US export control laws. Unauthorized export or re-export is prohibited. 2 © 2013, General Electric Company. Proprietary information. All rights reserved. Concerns facing the global energy industry today Emissions Energy securitycosts Fuel Fuel diversification Changing Resource regulatory Increasing scarcity landscape renewables Grid stability Economic uncertainty Ancillary industry opportunities industry Ancillary 3 © 2013, General Electric Company. Proprietary information. All rights reserved. But, resources and fuels are regional E. Europe •
    [Show full text]
  • Fundamentals of Energy Determination
    FUNDAMENTALS OF ENERGY DETERMINATION David Hailey, Ph.D. Cosa Instrument Corp 7125 North Loop East Houston, TX 77029 Abstract This paper presents fundamental information necessary to understand and appreciate the concept of total gas energy in a natural gas pipeline. That is, to be able to converse with peers within the natural gas industry and understand basic concepts and terminology. Discussed is the historical transition from volumetric measurement to total gas energy including some of the basic terminology, physics, measurement, as well as the reasons for changes in methodologies. Included is industry acceptance of new concepts and regulations involving custody transfer as well as the instrumentation and systems involved in traditional and newer, more progressive forms of gas measurement. Figure 1 Figure 2 illustrates the Ocean at 50 to 100 Where Does Natural Gas Come From? million years ago. Over millions of years, the remains were buried deeper and deeper. The Millions of years ago, the remains of plants and enormous heat and pressure turned them into oil animals decayed and built up in thick layers. and gas. This decayed matter from plants and animals is called organic material -- it was once alive. Over time, the mud and soil changed to rock, covered the organic material, and trapped it beneath the rock. Pressure and heat changed some of this organic material into coal, some into oil (petroleum), and some into natural gas -- tiny bubbles of odorless gas. The main ingredient in natural gas is methane, a gas (or compound) composed of one carbon atom and four hydrogen atoms. Figure 1 shows an Ocean bed at 300 to 400 million years ago.
    [Show full text]
  • Wobbe - Index Prof
    Formulary Waste Management Page 1/2 Wobbe - Index Prof. Dr. Werner Bidlingmaier & Dr.-Ing. Christian Springer Projekt Orbit | Dr. W. Bidlingmaier | Bauhaus Universität Weimar | www.orbit-online.net Wobbe - Index: The Wobbe - Index (WI) or Wobbe number is an indicator of the interchangeability of fuel gases such as natural gas, liquefied petroleum gas (LPG), and town gas and is frequently defined in the specifications of gas supply and transport utilities. The Wobbe - Index was defined 1927 by the engineer Goffredo Wobbe. It allows the compatibility of different fuels. The Wobbe Index is used to compare the combustion energy output of different composition fuel gases in an appliance (fire, cooker etc.). If two fuels have identical Wobbe Indices then for given pressure and valve settings the energy output will also be identical. Typically variations of up to 5% are allowed as these would not be noticeable to the consumer. The Wobbe-Index is the quotient of the square root of the relation density fuel / air and the upper calorific value. To measure the Wobbe -Index a test gas is burned under standardized conditions. Hereby a gas mantle is heated and the temperature is measured. In comparison to a calibration gas the Wobbe-Index for a gas can be determed. Unit: kWh/Nm³ = 3,6 MJ/Nm³ = 3,6·106 J/Nm³ (1 Nm³ = 1 m³ under normal pressure: 1.013,25 mbar, 0 °C) Formulary Waste Management Page 2/2 Wobbe - Index Prof. Dr. Werner Bidlingmaier & Dr.-Ing. Christian Springer Projekt Orbit | Dr. W. Bidlingmaier | Bauhaus Universität Weimar | www.orbit-online.net Calculation: The Wobbe Index, , is defined as: or H H W = on bzw W = un on d un d Wo,n upper Wobbe-Index Wu,n lower Wobbe-Index Ho,n upper calorific value Hu,n lower calorific value ρL density air ρG density fuel d rel.
    [Show full text]
  • Monitoring the Wobbe Index of Natural Gas Using Fiber-Enhanced Raman Spectroscopy
    sensors Article Monitoring the Wobbe Index of Natural Gas Using Fiber-Enhanced Raman Spectroscopy Vincenz Sandfort 1, Barbara M. Trabold 2, Amir Abdolvand 2,3, Carsten Bolwien 4, Philip St. J. Russell 2, Jürgen Wöllenstein 1,4 and Stefan Palzer 5,* ID 1 Laboratory for Gas Sensors, Department of Microsystems Engineering–IMTEK, University of Freiburg, Georges-Köhler-Allee 102, 79110 Freiburg, Germany; [email protected] 2 Max Planck Institute for the Science of Light, Staudtstraße 2, 91058 Erlangen, Germany; [email protected] (B.M.T.); [email protected] (A.A.); [email protected] (P.S.J.R.) 3 School of Electrical and Electronic Engineering, Nanyang Technological University, 50 Nanyang Ave, Singapore 639798, Singapore 4 Fraunhofer Institute for Physical Measurement Techniques IPM, Heidenhofstraße 8, 79110 Freiburg, Germany; [email protected] (C.B.); [email protected] (J.W.) 5 Department of Computer Science, Universidad Autónoma de Madrid, Francisco Tomás y Valiente 11, 28049 Madrid, Spain * Correspondence: [email protected] Received: 26 October 2017; Accepted: 23 November 2017; Published: 24 November 2017 Abstract: The fast and reliable analysis of the natural gas composition requires the simultaneous quantification of numerous gaseous components. To this end, fiber-enhanced Raman spectroscopy is a powerful tool to detect most components in a single measurement using a single laser source. However, practical issues such as detection limit, gas exchange time and background Raman signals from the fiber material still pose obstacles to utilizing the scheme in real-world settings. This paper compares the performance of two types of hollow-core photonic crystal fiber (PCF), namely photonic bandgap PCF and kagomé-style PCF, and assesses their potential for online determination of the Wobbe index.
    [Show full text]
  • How to Measure Gas Quality the Composition of the Natural Gas Is Continuously Measured at a Number of Measurement Sites in Nybr
    How to measure gas quality The composition of the natural gas is continuously measured at a number of measurement sites in Nybro, Lille Torup, Stenlille, Egtved and Dragør. The measurement of gas composition is used to analyse and calculate calorific values, Wobbe index and other quality parameters of the natural gas. Calculating the delivered energy to the customers is performed on the basis of all the analyses and calculations. The method of calculation takes into consideration regional differences in gas composition as a result of the actual operating conditions. The information is not to be used to calculate the size of the gas settlement for the particular month in question, but solely to evaluate operating conditions. Calorific value, hydrogen sulphide, overall sulphur content, Wobbe index and methane number are described below: The calorific value The overall term describes the amount of heat generated during combustion of the natural gas. The customer pays for the delivered amount of energy, and not for the delivered amount of natural gas. The calorific value is used to calculate how much energy each customer has received. The Net Calorific Value A term describing the amount of heat generated, when the temperature of the combustion air and the natural gas prior to combustion is 25°C, when the combustion products (flue gas) are cooled to 25°C, and when the water produced during combustion is present in the form of steam. The Gross Calorific Value A term describing the amount of heat developed by combustion of one cubic metre of gas at constant pressure when the gas and air for the combustion have a temperature of 25°C, the combustion products being brought to that temperature and the water formed by the combustion being present in liquid state.
    [Show full text]