Liquid Natural Gas (LNG) is an energy source that is becoming more important in energy transition, as the world is facing lower the CO₂ emissions and backup sources for wind and solar energy are needed. LNG is becoming a major player not only as fuel for power plants, but also in transport and mobility. However, the composition of LNG varies significantly between the various production locations around the world, and the layering of hydrocarbons with different molecular weights takes place even in LNG containers. This is especially critical for LNG engines, in which the ignition properties of the gas depend heavily on the fuel quality or Methane Number (MN) of the gas. For optimized engine operation and motor management, this fuel quality should be measured regularly, preferably online and by a small and low-cost sensor. This paper presents two sensor solutions for the assessment of the full gas composition. For both sensors, the standard deviation in the composition of the relevant hydrocarbons was low enough to calculate the Methane Number with an accuracy of approximately 1 MN unit. It was demonstrated that the electronic capacitive sensor was better suited to assess the higher hydrocarbons, whereas the infrared sensor showed higher selectivity for the lower hydrocarbons.

HCl measurements in a cleanroom environment are carried out using a cavity ring-down analyser in order to get an estimate of the HCl concentrations that can be expected to be present in semiconductor manufacturing. HCl is a reactive gas and the materials used for gas sampling and transportation have a significant effect on the measurement response time; hence, data on HCl adsorption to different materials is also provided. Finally, a light source operating at 1742 nm that can be used for HCl detection in a multi-gas analyser based on multipass photo-acoustic spectroscopy is presented. Preliminary results indicate that sub-ppb detection levels are achievable using this approach even for HCl.

The energy market is facing a major transition, in which natural gas and renewable gasses will play an important role. However, changing gas sources and compositions will force the gas transporters, gas engine manufacturers, and gas grid operators to monitor the gas quality in a more intensive way. This leads to the need for lower cost, smaller, and easy to install gas quality sensors. A new approach is proposed in this study that is based on the chemical interactions of the various gas components and responsive layers applied to an array of capacitive interdigitated electrodes. For Liquid Natural Gas (LNG), containing a relative high concentration of higher hydrocarbons, an array of ten capacitive chips is proposed, that is sufficient to calculate the full composition, and can be used to calculate energy parameters, such as Wobbe Index, Calorific Value, and Methane Number. A first prototype was realized that was small enough to be inserted in low and medium pressure gas pipes and LNG engine fuel lines. Adding the pressure and temperature data to the chip readings enables the determination of the concentrations of the various alkanes, hydrogen, nitrogen, and carbon dioxide, including small fluctuations in water vapor pressure. The sensitivity and selectivity of the new sensor is compared to a compact analyzer employing tunable filter infrared spectrometry.

For reactive gaseous compounds, limited availability of bottled standard gases often limits their measurement accuracy and comparability. Typically, an available reference gas concentration range for the specific compounds may be limited to even orders of magnitude higher than the levels normally measured at atmospheric measurements and most often only dry reference gases in inert matrices, typically nitrogen, are available. This means that when applying test gases from cylinders humidity in measurement system may cause significantly longer measurement response than in normal operation. A real-time reference gas generation is an effective method to circumvent these obstacles. Controlled evaporation of the reference solution enables flexible and reliable generation of test gases in wide concentration and flow ranges as well as in different gas matrices. The method is useable in field conditions and it may provide cost savings since necessary consumables include solely pure carrier gas and solution of the studied chemical with know concentration. We validate this method for different reactive gaseous compounds and key impurities. For mercury chloride, the most typical form of oxidised mercury in process emissions and atmosphere, reference gas with concentration ranging from sub-ng/m3 to tens of µg/m3 is generated. In case of typical base and acid trace impurities, ammonia, hydrogen chloride and hydrogen fluoride, the reference gases are generated in (bio-) methane and air matrices. In all cases studied, the stabilization time of generating gas flow is no longer, than some minutes. Accuracy and traceability of the generated gas concentration are estimated based on full uncertainty calculation as well as comparison with traceable reference gas standards.

Agricultural processes are the main source of ammonia emissions, and they are a significant source of methane emissions. For quantification of emissions from livestock animal housings onsite measurements for these gases are needed in parallel with certified reference standards that enable SI-traceability of the measurement results. We have developed dynamic reference gas generation method that is suitable for onsite use when calibrating the analysers and sensors applied either inside or outside the animal housings, for determination of ammonia concentrations in large enough concentration range spanning several orders of magnitude. In combination with static reference gas mixtures for greenhouse gases that are measured in parallel with ammonia, this method is used to calibrate and validate measurements of these most important molecular emissions from agriculture. We present the results of application of this methodology onsite for calibration of different types of sensors and analysers that provide the primary concentration data used in calculations sourcing data for corresponding emissions inventory reports.