Pervaporation unit with MEMS gas sensor for the measurement of methane concentration in water

The monitoring of concentration of methane dissolved in water is important for the security of underwater pipelines, delineation of oil and gas fields, and optimization of proper location of oil and gas wells. The reported system consists of metal oxide gas sensor separated from water by hydrophobic pervaporation membrane. Methane MEMS sensor was based on multilayer SiO 2 /Si 3 N 4 film equipped with platinum heater and coated with sensing layer made of nanoparticle SnO 2 /Pd (3 wt. %). Methane saturation of water leads to a decrease in sensor resistance by a factor of 6 – 7, the response time of the system is of 200–300 s.