One significant area of research in fuel cell technology includes systems in which a fuel cell is combined with another power generation device (a turbine, for example) to create a hybrid system that combines the advantages of the two standalone systems, resulting in a high fuel-to-electricity conversion efficiency. Burners are used as the primary or auxiliary energy source in the turbine portion of the hybrid system. These burners usually have one or more sources or inlets using one or more hydrocarbon-based fossil fuels such as natural gas, liquefied petroleum gas, and liquid hydrocarbon-based fuels. Accurate monitoring and control of such a combustion process is very important to ensure the efficient and safe operation of the hybrid systems.
To optimize the performance of certain industrial processes or apparatus, such as hybrid power generation systems consisting of a fuel cell and a turbine, it is necessary to know the flow direction and velocity of gases such as air through the system. Differential pressure sensors have been used for this purpose, but they can measure flow only in one direction, are slow to respond, and require a high pressure differential to provide accurate flow measurements.
A sensor system and process were developed for multidirectional, real-time monitoring of the flow direction and velocity of a gas stream with minimal pressure drop, such as airflow in a hybrid power generation system. The sensor comprises an ion source accompanied by a multidirectional ion collection device near the ion source.
The method uses a flame to ionize the gas (similar to a flame ionization detector) and electrode pairs arranged along common flow axes to collect the ions. The axis of electrode pairs responding to the ion flow determines the flow direction; the rate of ion collection per unit time determines the flow velocity. This sensor has no moving parts, and is effective in low-pressure differential conditions.