Method for adapting the concentration of a sample gas in a gas mixture to be analysed by a gas chromatograph assembly (10), the gas chromatograph assembly (10) comprising a sample gas inlet (20) for introducing a sample gas to be analysed, a secondary gas inlet (40), a gas chromatograph infrared sensor (12), a gas chromatograph column (26), and a gas chromatograph bypass (28) parallel to the column (26), characterized by a) introducing an amount of sample gas through the sample gas inlet (20), b) introducing an amount of secondary gas through the secondary gas inlet (40), c) mixing the sample gas and the secondary gas to a gas mixture and conducting the gas mixture via the gas chromatograph bypass (28), d) circulating the gas mixture in a gas conducting loop (52) comprising the gas chromatograph bypass (28), the gas chromatograph infrared sensor (12) and not comprising the gas chromatograph column (26), e) analysing the gas mixture thus obtained by means of gas chromatography employing the gas chromatograph column (26) and the gas chromatograph infrared sensor (12).

Embodiments of the present disclosure relate to apparatus, systems, and methods for detection and differentiation of selected hydrocarbon gases in a target gas composition. The apparatus comprises a sensing unit; a housing comprising a first housing portion and a second housing portion, the first housing portion for receiving a linear actuator, the linear actuator operatively coupleable to the sensing unit proximal to the inlet, and the second housing portion for receiving at least a portion of the inlet end of the sensing unit and comprising at least one chamber and a closure member housed within the second housing portion and adjacent the inlet, the closure member actuatable between a closed state and an open state by the linear actuator; wherein the at least one chamber is in fluid communication with the inlet when the closure member is in the open state.

A concentration measuring device includes a circulation passage, an aspirator, a differential pressure sensor, and a control unit. The aspirator is disposed in a fuel tank and is connected to the circulation passage. While a gas flows from a gaseous layer within a fuel tank through the circulation passage due to a negative pressure generated in the aspirator, the differential pressure sensor measures a pressure difference of the gas within the circulation passage between an upstream side of a narrowed part, having a narrower passage area than an adjacent portion of the circulation passage, and a downstream side of the narrowed part. The control unit is configured to calculate a density of the fuel vapor from the pressure difference of the gas and to calculate a concentration of the fuel vapor from the density of the fuel vapor.

A method of vaporising liquefied natural gas (LNG) for measurement of its constituent components may include receiving LNG from a main pipeline into a pressurising device. The method may also include via the pressurising device, pressurising a the LNG beyond a critical pressure thereof. The method may further include directing a first portion of the pressurised LNG to a heater. The method may still further include via the heater, heating the first portion of pressurised LNG beyond a critical temperature thereof, and directing the pressurised and heated LNG to a vaporising device. The method may also include via the vaporising device, depressurising the heated LNG to a pressure below the critical pressure so as to vaporise the LNG.

A method for monitoring air quality is described. The method includes measuring ethane and methane using a mobile sensor platform to provide sensor data. The sensor data includes methane data and ethane data captured at a nonzero mobile sensor platform speed. Methane and ethane peak(s) are identified in the sensor data. Correlation(s) between the methane and ethane peak(s) and/or between the methane peak(s) and at least one amount of .sup.13C are determined. A source for the methane is determined based on the correlation.

Methods and apparatus for sensing hydrogen in a mixture of hydrogen and natural gas are provided. One example of the apparatus comprises: a first chamber for receiving air; a second chamber for receiving the mixture of hydrogen and natural gas; a first electrode for adsorbing oxygen molecules from air in the first chamber and for reducing the oxygen molecules to oxide ions; a second electrode; an ionic conductor for transporting the oxide ions from the first electrode to the second electrode in order to cause the transported oxide ions to combine with hydrogen molecules at the second electrode; sensing circuitry for sensing an electrical parameter associated with the combination of the transported oxide ions with the hydrogen molecules at the second electrode; and processing circuitry configured to determine a proportion of hydrogen in the mixture, based at least in part on the electrical parameter sensed by the sensing circuitry.

A method is provided for estimating at least one combustion characteristic of a fuel gas belonging to a family of fuel gases, where the at least one characteristic includes at least one of a Wobbe index or a higher heating value. The method includes measuring at least two flow properties of the fuel gas and measuring a dihydrogen content X.sub.H.sub.2 contained in the fuel gas. The method also includes estimating the at least one characteristic ${\Xi }_{\frac{\mathrm{GN}}{H2}}$
using an empirical affine relationship of ${\Xi }_{\frac{\mathrm{GN}}{H2}}=\alpha +\beta .Math.Y+\gamma .Math.X_{H_2}.$
Here, α, β, and γ are coefficients predetermined for the family of fuel gases, and Y is a variable representative of physical properties of the fuel gas prepared from the measurements of the at least two flow properties of the fuel gas.

An X-ray fluorescence analyzer according to an embodiment includes a sample box configured to accommodate a liquid sample, an X-ray generation unit configured to irradiate an X-ray to one side surface of the inside of the sample box, and a detector disposed along one side surface of the sample box at which a distance of a fluorescent X-ray emitted from the inside of the sample box to the outside of the sample box is shortest in order to minimize absorption of the fluorescent X-ray emitted out of the sample box in the air, when the X-ray irradiated by the X-ray generation unit reacts with the liquid sample inside the sample box to emit the fluorescent X-ray out of the sample box, the detector being configured to detect the fluorescent X-ray.

A gas leak detection system that combines sensor units having an array of sensors that detect natural gas and the volatile organic compounds and variable atmospheric conditions that confound existing gas leak detection methods, a specially designed sensor housing that limits the variability of those atmospheric conditions, and a machine learning-enabled process that uses the wide array of sensor data to differentiate between natural gas leaks and other confounding factors. Multiple low-cost sensor units can be used to monitor gas concentrations at multiple locations across a site (e.g., a well pad or other oil or natural gas facility), enabling the gas leak detection system to model gas leak emission rates in two- or three-dimensional space to reveal the most likely origin of the gas leak.

A method for monitoring air quality is described. The method includes measuring ethane and methane using a mobile sensor platform to provide sensor data. The sensor data includes methane data and ethane data captured at a nonzero mobile sensor platform speed. Methane and ethane peak(s) are identified in the sensor data. Correlation(s) between the methane and ethane peak(s) and/or between the methane peak(s) and at least one amount of .sup.13C are determined. A source for the methane is determined based on the correlation.