Variability in the wobbe index affects most significantly engines that are not equipped with closed loop controls. The measured residual oxygen content provides a measurement of the combustionair requirement index cari and good correlation to the wobbe index of the gas. This international standard specifies methods for the calculation of the superior calorific value, inferior calorific value, density, relative density and wobbe index of dry natural gases, natural gas substitutes and other combustible gaseous fuels, when the composition of the gas by mole fraction is known. Wobbe index 50 mjnm3 span in 0100 mjnm3 range accuracy 0,4 % of measured value for natural gas repeatability 30kjnm3 drift wobbe index and calorific value of natural gas when mixed with it reduction depends on natural gas composition not only wigcv is affected acceptable concentrations of hydrogen are different today for different end uses many consequences of hydrogen admixtures are qualitatively rather similar to gas natural fluctuations. In europe a gas interchangeability index the wobbe index is also specified. Specifies methods for the calculation of the superior calorific value and the inferior calorific value, density, relative density and wobbe index of dry natural gas and other combustible gaseous fuels, when the composition of the gas by mole fraction is known. Apparatus for measuring the combustion characteristics of a gaseous fuel. The wobbe index in the hgas standard and how to include. Replaces the first edition, which has been technically revised. Comparison of wobbe index in various substrate wobbe index from the experiment in three difference substrate comparison with wobbe index standard from natural gas quality for vehicle standards by the department of energy business, ministry of energy, thailand 6 is shown in fig. Pdf from natural gas to hydrogen via the wobbe index. The heating value or energy value or calorific value of a substance, usually a fuel or food see food energy, is the amount of heat released during the combustion of a specified amount of it the calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard conditions. The wobbe index meter wim measures the wobbe index and the air demand of natural gas, refinery fuel gases and biogas.
The wobbe index is essential for analyzing the impact of a fuel changeover and is also a common specification of appliances that use gas and of devices that. Joint cenentsog workshop on wobbe index and gross calorific. Wobbe index is used to compare the combustion energy output with different composition of fuel gases. This residual oxygen content provides an accurate measurement of the combustion air requirement and correlates well to the. However, it is unclear whether the entire range of enduse equipment can accept the. Wobbe index meter, gas stability system, yamatake heat. Gas analysis for composition, wobbe index and dewpoint. A dictionary of weights, measures, and units authors. The measuring principle is based on the analysis of the oxygen content in the flue gas after combustion of the sample. The wobbe index and natural gas interchangeability pdf.
This calculator uses iso 6976 to determine the wobbe index along with the higher heating value, lower heating value, density and specific gravity of a natural gas blend. Gas quality the effects of hydrogen on wobbe index entsog. Heating value and wobbe index measurement in natural. Master thesis wobbe meter university of twente student theses.
Integrated micro wobbe index meter, and a multiparameter flow measurement system for the energy content measurement of fuel gases such as natural gas, biogas and hydrogen based on a microcoriolis mass flow meter, suitable of measuring flow rate and density of gases first measurement results have indicated the feasibility of the concepts. Wobbe index and modified wobbe index formula mechanical. For wobbe index measurement an additional co2 optical bench. Comparison of biomethane gas wobbe index in different. Effects of natural gas composition variations on the. An emerson gas chromatograph provides the accurate, reliable data that is required to ensure no damage to the equipment results from operating on low or midrange wobbe gas. The cosa 9610 wobbe index meters measuring principle is based on the analysis of the oxygen content in the flue gas after combustion of the sample. In particular we study the impact of changes to calorific value heat content and wobbe index combustion performance on large gas turbines and gas engines used for power generation. The wobbe index is a measure of the interchangeability of gases when they are used as a fuel. Gas quality the effects of hydrogen on wobbe index joint cenentsog workshop on wobbe index and gross calorific value in the european gas value chain 28th september 2017 jose a. This standard specifies methods for the calculation of the superior calorific value, inferior calorific value, density, relative density and wobbe index of dry natural gases, natural gas substitutes and other combustible gaseous fuels, when the composition of the gas. The modified wobbe index is a calculated measurement of volumetric energy content of fuel and is directly related to the fuel temperature and lower heating value lhv.
A continuous gas sample is mixed with dry air at a precisely maintained constant ration, which depends on the btu range of the gas to be measured. To convert the residual oxygen percentage to a wobbe index value the analyzer is calibrated with twogases with known wobbe index values. Integrated wobbe index meter in the last fifty years the composition of natural gas in the dutch gas grid was very constant. The northdome sensor is the perfect solution for integrating into a wobbe index analyzer to provide a realtime feedforward measurement of fuel gas density and energy content combustion energy output to enable improved control of combustion process. Wobbe index for common fuel gases propane, butane, methane and more sponsored links the wobbe index indicates the interchange ability of a fuel gas and is the best indicator of similarity between natural gas and a specific propaneair mixture. The inverse of the root of the relative density, which is a good approximation of the relative mass flow rate of a gas through a fixed orifice at a fixed pressure. The success in meeting these objectives in the longer term is, in fact, thwarted by the narrowness of the wobbe band. An indicator of the quality of a fuel gas, measured from the heat produced by burning through a defined orifice in standard temperature and pressure conditions, quantitatively defined as the ratio of btus per cubic foot to the square root of the specific gravity of the gas.
British standard 7859 provides all the details on standard conditions, component heating values, ideal vs. Realtime wobbe index determination of natural gas j. It measures in real time the wobbe index, calorific value and specific gravity. Analyzers measuring principle is based on the analysis of the oxygen content in the flue gas after combustion of the sample. Currently this is achieved using multiple analyzers. Measuring wobbe index turbine damage can be the result from high dynamics that result from variations in the wobbe index. The wobbe index, or wi, value of the gas supplied from the gulf of thailand to the mother station is at 44 mjcbm, well above the figure of 38 mjcbm for the gas imported from myanmar and the department of energy businesss benchmark range of 3742 mjcbm for domestic automobile fuel. Monitoring the wobbe index of natural gas using fiber.
Nitrogen or another selected component can be determined by balance. Wobbe indexcalorific value measurements handout significance of measurement tighter emission regulations and highenergy costs pose new challenges to control systems for fired heaters. The wobbe index is a critical factor to minimize the impact of fluctuations in your fuel gas supply and can therefore be used to increase the efficiency of your burner or gas turbine applications. Design considerations for heated gas fuel ge power systems ger4189b 0303 2. The wobbe index is a measure for the heating value of a gas composition and is the mostfrequently used indicator for the quality of natural gas and the interchangeability of different gas types. Wobbe index analyzer, calorimeter, online btu cosa 9610. The wobbe index wi or wobbe number is an indicator of the interchangeability of fuel gases. Natural gas, total sulfur, wobbe index, vcsel, so2, spectroscopy abstract in natural gas applications it is often desirable to know the total sulfur content of the gas to verify environmental regulation compliance, and also the wobbe index of the gas to characterize its energy content. Wobbe index and calorific value are measured with a fast response time by maintaining a stoichiometric mixture in a mixer supplied with the gaseous fuel at a constant pressure together with ambient air. The content of this publication shall be kept confidential by the customer, unless. The higher heating value, which is a measure of the energy per volume for the gas being considered.
The pressure of ambient air is controlled by measuring the residual oxygen from combustion of the mix and employing. It is expected that the gas quality bands are going to vary much more due to changes of the main gas supply streams in europe and the increasing use of lng. It compares the energy output of different gases during combustion. The wobbe index wi is an important gas quality indicator for most gasburning. The chemical reaction is typically a hydrocarbon or other.
Both options do not allow selective measurements of ethane, propane, etc. The instrument is a high speed combustion calorimeter complemented by the sampling system naphtha removal for blastfurnace gas and coke oven gas. For wobbe index measurement an additional co 2 optical bench with the measurement range of 0 to 5% or 0 to 20% is integrated into the analyzer. Designed and manufactured in the netherlands, it builds on over 20 years of the successful wirox, wim 9600 and wim 9900 series. Ger4189b design considerations for heated gas fuel. In the case of natural gas molar mass 17gmol, the typical heating value is around 39mjnm. Further, most other natural gas deposits available for use in europe have a higher energy content and therefore a higher wobbe index. The wobbe index is the ratio of the specific energy of a gas to its relative flow rate as shown by its constituent components. We bring to you fast, retliable, accurate, maintenance free wobbe index analyzer catorimeter from cosa xentaur usa. Requirements on the quality of natural gas euromot. Check the standard reference conditions in your region to ensure correct results. Pure hydrogen is not an option as its wobbe index lies above the band at 48 mj m 3. Numerical investigation of methane number and wobbe index. The baggi bawia is an online process analyzer for combustible gases.
Specific gravity heating value wobbe index cari combustion air requirement index. The wobbe index indicates the interchange ability of a fuel gas and is the best indicator of similarity between natural gas and a specific propaneair mixture. The wobbe index wi is the main indicator of the interchangeability of fuel gases and is frequently defined in the specifications of gas supply and transport utilities. 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 if is the higher heating value, or higher calorific value, and is the specific gravity, the wobbe index, is defined as. Trabold 2, amir abdolvand 2,3, carsten bolwien 4, philip st.
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