Natural gas (i.e. methane) is a key resource for the energy and fuel market of the next two decades. Above all, methane as a fossil fuel has a lower carbon footprint than coal and oil, so it is going to play a fundamental role in the transition to renewables. Furthermore, it can be easily replaced with biomethane. Biomethane production has greatly increased since 2011, raising from 752GWh in 2011 to 17,264GWh in 2016 (+2,196%), confirming an exceptionally rapid growth of this sector. Similarly to natural gas and methane, also biogas and biomethane need continuous monitoring and control of the composition in both of the stages of production and distribution. The purpose of this project is the design and development of a compact, light, low-cost Raman instrument prototype with low power consumption for on-line monitoring of natural gas, methane mixtures, biogas and biomethane composition.
Raman spectroscopy is a well-developed diagnostic technique with applications both in the scientific as well as in the industrial domain, thanks to exceptional developments in the fields of high sensitivity imaging sensors as well as in the high power, efficient laser sources. Portable, hand-held type Raman sensors are nowadays commercially available for the detection of many products from the pharmaceutical to food analysis to security screening. These devices are always meant for detection in solid or liquid samples. Raman spectroscopy of gases is much less developed due to the fact that the intensity of the Raman scattering, being proportional to the material density in the interaction region, is roughly 1000 times weaker than the signal from solid samples. Presently, only few companies offer Raman instruments for gases but these instruments are very bulky (since they use powerful lasers) and very expensive (in the range of 80-100k€ or even more) thereby limiting the use of this technology for widespread applications.
The breakthrough innovation proposed in this project will be possible thanks to novel concepts in both high efficiency optics for the detection of the weak Raman signal, as well to sophisticated image and signal processing techniques to compensate the relatively poor quality of the laser source used for the excitation. At present, such an instrument is not available on the market and could find numerous applications. We plan to address, in this first project step, the field of combustible gas diagnostic due to the high potential market impact. An instrument like the proposed one will be ideally suited for the determination of the components being either the various main hydrocarbons as well as other gases like N2, CO2, O2, H2O etc. often found as impurities. Thanks to the low power consumption, such an instrument could be installed even in unmanned remote locations, being powered by solar panels and backed up by small batteries.