Thermal conductivity microsensor for determining the Methane Number of natural gas

Puente, David; Gracia, F.J.; Ayerdi, I.

doi:10.1016/j.snb.2005.01.026

Cited by 23 publications

(14 citation statements)

References 3 publications

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“…Similar curves can be developed for the other gas mixtures (see Supplemental Information). Using these composition curves for ∆T and X, it is possible to determine the composition of a binary gas 8 mixture. By measuring the 3ω signal for a binary mixture (of one of the four gas mixtures used in this study), the linear composition curve for the corresponding signal will result in a unique value of concentration of the trace gas.…”

Section: Determining Gas Compositionmentioning

confidence: 99%

“…Specifically, miniature TCDs are highly desirable for gas chromatography [6,7]. Current manifestations use a platinum heater resting on a silicon nitride membrane as the sensor element [8], where the total size of membrane structure may exceed 0.5 mm. In one of the latest advancements, a doped polysilicon microbridge with very low thermal mass was developed that allows for ultra-fast thermal response [9].…”

Section: Introductionmentioning

confidence: 99%

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A microbridge heater for low power gas sensing based on the 3-Omega technique

Kommandur

Mahdavifar

Hesketh

et al. 2015

Sensors and Actuators A: Physical

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The 3-Omega measurement technique was applied to a microbridge heater for the purpose of low power gas sensing. The sensor performance was evaluated for mixtures of CO 2 , Ar, He and CH 4 in N 2 in an isothermal chamber where concentrations were precisely controlled by mass flow controllers. A custom 3-Omega conditioning circuit controls the AC heating current and detection of the 3-Omega voltage signal. The amplitude and phase lag, and the in-phase and outof-phase components of the 3-Omega signal are presented for each case and are related directly to gas concentrations. Advantageously, the phase lag can determine the gas concentration without calibration of an individual gas sensor. Using this technique and our current microbridge thermal conductivity detector (TCD), it is possible to resolve gas concentrations down to 0.07%. The frequency behavior of the 3-Omega signal as it pertains to the thermal environment and sensor sensitivity is discussed. The 3-Omega technique combined with the microbridge is capable of operating with power consumptions that are < 10 % of the power consumed by conventional Wheatstone bridge measurements at room temperature.

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Section: Determining Gas Compositionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A microbridge heater for low power gas sensing based on the 3-Omega technique

Kommandur

Mahdavifar

Hesketh

et al. 2015

Sensors and Actuators A: Physical

View full text Add to dashboard Cite

show abstract

“…In a closed combustion engine, a gas engine (reciprocating gas engine), one of the gas quality parameters used is methane number (MN). The MN is defined as the percentage of methane in a methane/hydrogen mixture which has the same knocking behavior as the gas mixture to be investigated under well-defined testing conditions [1][2][3]. Knocking in internal combustion engine results from the spontaneous ignition of a portion of the end gas mixture in the combustion chamber ahead of the propagating flame [4][5].…”

Section: Introductionmentioning

confidence: 99%

Methane Number Improvement of Gas from LNG Regasification Unit

Tjojudo

Kartohardjono

2018

E3S Web Conf.

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Methane Number (MN) is one of quality requirement of gas as fuel for gas engine, which indicates fuel capability to avoid knocking in the engine. Higher MN provides better quality of gas for gas engine. Natural gas with higher methane (CH4) and fewer higher hydrocarbon, tends to have higher MN score. This study aims to obtain heating methods of LNG to produce vapor that has appropriate MN as a fuel gas supply to gas engine. The simulation for LNG regasification prepared is an approach to the design of the existing regasification facility of the power plant in Bali. The temperature ranges for LNG heating simulation were obtained based on saturated temperatures of LNG phase envelopes. In the simulation. to obtain a certain MN value can be conducted by adjusting the temperatures at two different values i.e. above -110 ° and below - 80 °. To produce LNG vapor that has MN of 80 either through higher temperature of heating (HT heating) or lower temperature of heating (LT heating) requires more energy than direct heating without MN improvement. Heat loading for LT heating is higher than HT heating due to more temperature defference between LT and heating fluid temperatures. The ability of engine to produce power decreased with decreasing fuel gas MN. The power increment increases for lower MN gas if MN improvement is conducted.

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“…Therefore, measurements can be taken more rapidly and the sensor can be operated in a continuous manner and repeatedly used without memory effects. Puente et al 8 demonstrated a thermal conductivity micro-sensor for measurement and analysis of natural gas composition. Miniature thermal conductivity gas sensors have been developed as detectors for gas chromatography (GC) systems in which very fast response is required for the detector.…”

Section: Introductionmentioning

confidence: 99%

Transient thermal response of micro-thermal conductivity detector (µTCD) for the identification of gas mixtures: An ultra-fast and low power method

et al. 2015

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Micro-thermal conductivity detector (µTCD) gas sensors work by detecting changes in the thermal conductivity of the surrounding medium and are used as detectors in many applications such as gas chromatography systems. Conventional TCDs use steady-state resistance (i.e., temperature) measurements of a micro-heater. In this work, we developed a new measurement method and hardware configuration based on the processing of the transient response of a low thermal mass TCD to an electric current step. The method was implemented for a 100-µm-long and 1-µm-thick micro-fabricated bridge that consisted of doped polysilicon conductive film passivated with a 200-nm silicon nitride layer. Transient resistance variations of the µTCD in response to a square current pulse were studied in multiple mixtures of dilute gases in nitrogen. Simulations and experimental results are presented and compared for the time resolved and steady-state regime of the sensor response. Thermal analysis and simulation show that the sensor response is exponential in the transient state, that the time constant of this exponential variation was a linear function of the thermal conductivity of the gas ambient, and that the sensor was able to quantify the mixture composition. The level of detection in nitrogen was estimated to be from 25 ppm for helium to 178 ppm for carbon dioxide. With this novel approach, the sensor requires approximately 3.6 nJ for a single measurement and needs only 300 µs of sampling time. This is less than the energy and time required for steady-state DC measurements.

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Thermal conductivity microsensor for determining the Methane Number of natural gas

Cited by 23 publications

References 3 publications

A microbridge heater for low power gas sensing based on the 3-Omega technique

A microbridge heater for low power gas sensing based on the 3-Omega technique

Methane Number Improvement of Gas from LNG Regasification Unit

Transient thermal response of micro-thermal conductivity detector (µTCD) for the identification of gas mixtures: An ultra-fast and low power method

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