Method of determining the gas quality
AssigneeFlowcomp Systemtechnik GmbH
InventorsDieter Stirnberg, Joachim Kastner
Life of this patent
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Abstract
The invention relates to a method of determining mainly the compressibility number K, the standard volumetric gross calorific value Hv,n and the standard density ρn of test gases using values determined from a spectrum of the test gases. The invention describes various approaches of translating the values for determining the desired values using the data of the spectrum in the operational condition to the standard reference condition using two-step iteration processes without having to subject the test gases to time-consuming treatments. The invention further relates to devices for determining the values required for the methods and which further develop devices for carrying out the methods.
Claims22
Procedure for the determination of the quality of gas of a probe gas, proceeding from a transmission spectrum of the probe gas determined at operating conditions by means of spectroscopical methods of measurement, comprising
- determining at operating conditions out of the transmission spectrum the amounts of substances xi of the components of the probe gas,
- presetting default values for a compressibility factor K and real gas factor Zn for calculation of the compressibility factor K,
- out of quantities at operating conditions of the probe gas as well as from the amounts of substances xi and substance specific quantities and taking into account of the preset default values for compressibility factor K and real gas factor Zn determining input quantities for the determination of the compressibility factor K,
- calculating with these input quantities the compressibility factor K by means of a standard-arithmetic procedure, and
- carrying out an iterative calculation in the way of an iterative recalculation of the input quantities with the determined value for the compressibility factor K, until the value of the compressibility factor K converges and then from the volumetric standard calorific value Hv,n, the standard density ρn is calculated.
Procedure for the determination of the quality of gas of a probe gas proceeding from a transmission spectrum of the probe gas determined at operating conditions by means of spectroscopical methods of measurement, comprising,
- presetting default values for compressibility factor K and real gas factor Zn for calculation of the wanted compressibility factor K,
- from the pressure pb at operating conditions and the temperature Tb at operating conditions of the probe gas with the values for the calorific value Hv,b at operating conditions and the density ρb at operating conditions, which can be directly determined out of the transmission spectrum, determining input quantities for the determination of the compressibility factor K,
- as further input quantity determining the molar amount of substance of CO2 by means of a further absorption band of the transmission spectrum,
- with these input quantities calculating the compressibility factor K by means of the iterational procedure GERG88,
- carrying out an iterative calculation in the way of an iterative recalculation of the input quantities with the determined value for the compressibility factor K, until the value of the compressibility factor K converges and then from the volumetric standard calorific value Hv,n the standard density ρn is calculated.
Photometric device for the determination of a transmission spectrum of a probe gas comprising
- a radiation source emitting a measurement radiation, in which the measurement radiation passes through a probe cell for capturing a probe gas and enters after passing through a modulation unit for modulating the measurement radiation into at least one radiation receiver, which generates electrical measurement signals according to an incoming intensity of the measurement radiation and transmits these to an electronic unit, which determines said transmission spectrum out of the measurement signals, wherein the modulation unit shows a spectral switch unit in the form of a chopper arrangement, which transmits because of their selective transmission behaviour only specific spectral regions of the transmission spectrum in the measurement radiation caused by the probe gas to the at least one radiation receiver;
- and
- wherein the chopper arrangement is provided with an aperture with a spiral opening in which the release of the regions of the wavelength of the measurement radiation is caused continuously for the whole spectrum.
Dependencies are inferred from the claim text.