Michell Instruments is partnering with VSL, the national metrology institute of The Netherlands, on a jointly EU and EURAMET funded project to increase the use of energy from renewable sources.
The European Community has set a target for 20 per cent of its energy consumption to come from renewable sources by 2020. One of the research projects set up to achieve this is Metrology for Biogas, a three-year programme which began in June 2014. Its purpose is to devise and validate traceable methods for determining key impurities, moisture, particulates, calorific value, and density in biogas and bio-methane so it can be used as a mainstream alternative to natural gas.
VSL is working on the measurement of moisture and water dew point calibration. As an industrial collaborator, Michell Instruments has provided a moisture analyser – the OptiPEAK TDL600 – for assessment testing. It uses advanced tuneable diode laser absorption spectroscopy, to provide a fast response to changes in moisture concentration whilst being able to withstand the acidic nature of the biogas.
Because the sensor uses laser light to measure moisture content, there is no contact between it and the biogas – meaning that there is no long-term degradation of performance or stability of the analyser from the corrosive elements of the gas.
The tests have been conducted on three compositions representing biogas, with 20 per cent concentration of carbon dioxide in methane, as well as processed biomethane with reduced CO2 concentrations including 100 per cent methane. Moisture contents in the range 10 to 1,000 ppmV were generated within the VSL primary high-pressure humidity generator. The Michell TDLAS analyser proved helpful to further the understanding of the relationship of dew-point temperature to moisture concentration in biogas which exhibits non-ideal behaviour.
The testing work is now complete, and the results will be published in a paper to be presented at NEN Gas Analysis, Rotterdam in June 2017.