PEFTEC 2019 - Abstract

Abstract Title: Methane measurements in monitoring biogas production and combustion
Abstract Type: Poster
Session Choice: Current capabilities and case studies
Presenter Name: Prof Ravi Fernandes
Co-authors:Dr Bert Anders
Dr Jürgen Rauch
Dr Kai Moshammer
Company/Organisation: Physikalisch Technische Bundesanstalt (PTB)
Country: Germany

Abstract Information :

To support the EU clean energy strategy and its Roadmap 2050, methane based fluid energy carriers (e.g LNG, CNG, Biogas/Biomethane) will play a dominant role in the future alternative energy mix. Alone in the year 2015, Germany added 150 Biogas production units and this number is expected to increase sharply. The European Commission has issued mandate M/475 to CEN, the European Organization for Standardization, concerning the specifications for biogas and biomethane for injection into natural gas grids and for use as transport fuel (prEN 16723). Similarly, LNG has also shown a huge potential as a clean transportation fuel due to its reduced emissions on combustion to meet the stringent pollutant emissions limits for EURO VI regulations.

However, methane itself is a greenhouse gas with a significant Global Warming Potential (GWP) ˜ 30 times higher than that of CO2, posing a serious threat on its leakage and as emissions during incomplete combustion. Moreover, it is crucial to determine the fuel gas composition for trade and legal metrology, to determine its energy content e.g. calorific value (CV), derived from the methane content. Despite its importance, traceable methane measurements, both on the production side (e.g. Biogas plants) as well on the combustion side (e.g. for calorific value, emissions) are lacking and remain a formidable task.

We will present our activities from ongoing projects for diverse applications, where both stationary and dynamic methane measurements are performed to ensure traceable measurement standards and to provide calibration methods.

The first application, focuses on monitoring biomethane production processes at several biogas plants in Germany, where field samples are analyzed using Gas Chromatography. In another project on biogas metrology, we determine the calorific value of biogas and biomethane samples with an uncertainty of 0.05% through direct methods (Reference gas calorimetry). Both Non-Dispersive Infra-Red (NDIR) detection of methane and Flame Ionization Detection (FID) for multicomponent hydrocarbon mixtures are employed to quantify unburnt fuel gas.

Finally, we will provide an outlook and scope of emerging time-resolved (µs) methane measurements for combustion processes using combined ND-IR spectroscopy and TOF-Mass Spectrometry (TOF-MS) in harsh but controlled environments such as Flames, Rapid Compression Machine, and Shock tubes currently being installed in our laboratories. A Quantum cascade laser (QCL) system working at a center wavelength around 7.7 µm enables the detection of methane in trace gas concentrations. With TOF-MS, methane is detected simultaneously with other chemical species in one single mass spectrum. These data can give remarkable insights in energy processes for methane based energy carriers, providing validation targets for model based process optimization.

The presentation will also highlight the needs and challenges of dynamic methane measurements for other advanced applications.