Abstract:
A valid state of an analytical system that includes a light source (102) and a detector (106) can be verified by determining that deviation of first light intensity data quantifying a first intensity of light received at the detector from the light source after the light has passed at least once through each of a reference gas in a validation cell (114) and a zero gas from a stored data set does not exceed a pre-defined threshold deviation. The stored data set can represent at least one previous measurement collected during a previous instrument validation process performed on the analytical system. The reference gas can include a known amount of an analyte. A concentration of the analyte in a sample gas in a measurement cell (112) can be determined by correcting second light intensity data quantifying a second intensity of the light received at the detector after the light passes at least once through each of the reference gas in the validation cell and a sample gas containing an unknown concentration of the analyte compound. Related systems, methods, and articles of manufacture are also described.
Abstract:
A spectrometer includes a light source configured to emit a beam along a beam path through a sample volume comprising an analyte. Also included is at least one detector positioned to detect at least a portion of the beam emitted by the light source, and at least one reflector positioned along the beam path intermediate the light source and the at least one detector having a surface roughness greater than a predefined level such as 20 Å RMS.
Abstract:
A spectrometer includes a light source that emits a beam into a sample volume comprising an absorbing medium. Thereafter, at least one detector detects at least a portion of the beam emitted by the light source. It is later determined, based on the detected at least a portion of the beam and by a controller, that a position and/or an angle of the beam should be changed. The beam emitted by the light source is then actively steered by an actuation element under control of the controller. In addition, a concentration of the absorbing media can be quantified or otherwise calculated (using the controller or optionally a different processor that can be local or remote). The actuation element(s) can be coupled to one or more of the light source, a detector or detectors, and a reflector or reflectors intermediate the light source and the detector(s).
Abstract:
Detector data representative of an intensity of light that impinges on a detector after being emitted from a light source and passing through a gas over a path length can be analyzed using a first analysis method to obtain a first calculation of an analyte concentration in the volume of gas and a second analysis method to obtain a second calculation of the analyte concentration. The second calculation can be promoted as the analyte concentration upon determining that the analyte concentration is out of a first target range for the first analysis method.
Abstract:
Validation verification data quantifying an intensity of light reaching a detector of a spectrometer from a light source of the spectrometer after the light passes through a validation gas across a known path length can be collected or received. The validation gas can include an amount of an analyte compound and an undisturbed background composition that is representative of a sample gas background composition of a sample gas to be analyzed using a spectrometer. The sample gas background composition can include one or more background components. The validation verification data can be compared with stored calibration data for the spectrometer to calculate a concentration adjustment factor, and sample measurement data collected with the spectrometer can be modified using this adjustment factor to compensate for collisional broadening of a spectral peak of the analyte compound by the background components. Related methods, articles of manufacture, systems, and the like are described.
Abstract:
An energy content meter can spectroscopically quantify oxidation products after oxidation of a combustible mixture. The measured oxidation product concentrations or mole fractions can be converted to an energy content of the un-oxidized combustible mixture using a conversion factor that relates oxygen consumption during oxidation of the combustible mixture to the energy content of the combustible mixture.
Abstract:
Thermodynamic properties of a natural gas stream can be determined in real time utilizing modeling algorithms in conjunction with one or more sensors for quantifying physical and chemical properties of the natural gas. Related techniques, apparatus, systems, and articles are also described. A method and apparatus for determining the energy content of a gas stream in which spectroscopic measurements on carbon dioxide and hydrocarbons as well as a third measurement of temperature, pressure and sund velocity of the gas are input to a processor which uses an algorithm to calculate the energy contact.
Abstract:
Concentrations of a target analyte in a gas mixture containing one or more background analytes having potentially interfering spectral absorption features can be calculated by compensating for background analyte absorption at a target wavelength used to quantify the target analyte. Absorption can be measured at a reference wavelength (302) chosen to quantify the concentration of the background analyte. Using a background gas adjustment factor or function, the absorption measured at the reference wavelength can be used to calculate absorption due to the background analyte at the target wavelength (304) and thereby compensate for this background absorption to more accurately calculate the target analyte concentration in real or near real time (306). Additional background analytes can optionally be compensated for by using one or more additional reference wavelengths.
Abstract:
Background composition concentration data representative of an actual background composition of a sample gas can be used to model absorption spectroscopy measurement data obtained for a gas sample and to correct an analysis of the absorption spectroscopy data (e.g. for structural interference and collisional broadening) based on the modeling.
Abstract:
A reference harmonic absorption curve of a laser absorption spectrometer can have a reference curve shape derived from a reference signal generated by the detector in response to light passing from the laser light source through a reference gas or gas mixture. The reference gas or gas mixture can include one or more of a target analyte and a background gas expected to be present during analysis of the target analyte. One or more portions of a test harmonic absorption curve having a test curve shape is compared with one or more portions of the reference harmonic absorption curve arising due to absorption of the background gases and not by absorption of the target analyte. Operating and/or analytical parameters of the laser absorption spectrometer are adjusted to correct the test curve shape to reduce the difference between the test curve shape and the reference curve shape.