In 2018 TNO developed new sensor chips that can be added to the existing multigas sensor array for the measurement of the higher hydrocarbons in LNG. For each of the target gasses in the LNG (i.e. methane, ethane, propane, iso & n-butane, iso & n-pentane and nitrogen) a sensor chip is required. These chips consist of an interdigitated electrode, coated with a responsive coating. This coating absorbs the gas and changes its dielectric constant, which is measured by the electrode. The new butane and pentane responsive coatings are made from mixtures of highly porous ceramic particles embedded in a highly permeable polymer matrix. Responses of the sensor to butane and pentane concentration variations of 0.1 vol% can be very well distinguished.
The final LNG composition sensor has ten coated electrodes, a temperature and a pressure sensing chip, which enables the calculation of the full LNG composition.
The sensor will be validated in laboratory gas mixtures and will be subsequently inserted in the fuel line of a real test engine.