MEMS-based catalytical sensors for flammable gases
The early detection of flammable gases or explosive mixtures is of great importance to avoid endangerment of human life, damaging of facilities, and natural gas transport losses. Millions of gas sensors are surveying the gas infrastructure at petrol stations, gas pipelines, or gas heaters in private homes in order to detect escaping flammable gases. These gas sensors are catalytic bead sensors, so called pellistors. They consist of two platinum heating coils sintered in ceramics. One coil is additionally loaded with a catalyst like Pt or Pd; the other coil is used as a reference to compensate disturbances like airflow. However, these pellistors need high working temperatures of ~450 °C and are therefore characterized by high power consumption of ~1 W. The pellistors must be protected from poisoning by silicon-, sulphur-, lead-, or chlorine-containing compounds and they have to be equipped with an explosion prevention device.
As part of the MEscal project, a cost-effective low-power sensor system is realized by combining innovative materials and a novel system setup. The catalytic gas sensors will consist of a MEMS-based low power substrate and a new catalytic-active material with a lower working temperature. The new catalytic-active material will allow for a lower working temperature, which improves poisoning and explosion protection and at the same time reduces power consumption. A further reduction of power consumption can be realized by the use of MEMS-based hot plates as substrates and by heating the catalytic-active material in a non-continuous operation.
The aim of the project partners is to develop an energy-efficient, low-cost and stable gas sensor for the qualitative detection of flammable gases such as methane or hydrogen. In a second step, based on that low power and low-cost catalytic sensor, a gas detector system for mobile applications will be developed.