Integral Packaging of High Temperature Chemical Sensors for In-Situ Measurements

Energy security comprises the foundation of the American standard of living, economy, and national security in the United States. While energy sources are becoming more diversified, fossil fuels are still the most prevalent and abundant source of energy, and will continue to account for a significant portion of the energy generated for the foreseeable future. A modest 1% heat rate improvement of the existing coal fired fleet would result in $300 million /yr in coal costs savings, and the reduction of 14.5 million metric tons of CO2 per year. Likewise, 1% increase in availability would generate more than 2 GW of additional power from existing coal fired fleet. These improvements require integrated control systems with real time process instrumentation (feed and product monitoring, temperature, pressure) to reduce system inefficiencies. Currently, conventional instrumentation is not capable of providing the necessary measurements in these types of harsh environments due in large part to packaging limitations. The focus of the proposed Phase I program is to develop an integral package to enable operation of MEMS sensors in the harsh environment associated with advanced power systems. The packaging will support chemical sensors such as the planar thick film high temperature sensors developed for CO and CO2 monitoring by our team and research partners. The integral design enables upgrading systems as newer sensor options become available, without having to re-develop new packaging solutions for other types of high temperate sensors with multi-conductors. Phase I includes extensive testing of the proposed package, both in a lab environment and at a local gasifier plant operated by West Biofuels in Woodland, CA. Lessons learned in testing will be incorporated in design iterations, resulting in a robust system that is easily installed and serviceable. Successful demonstration at this gasifier plant will lead to future long term Phase II testing focused on chemical sensors at a wide range of end user facilities including DOE coal fired facilities, as well as turbine and gasifier systems in operated by Sacramento Municipal Utility District (SMUD), Solar Turbines, Rolls Royce, and West Biofuels. The integral probe will have the following functionalities: (1) Insert sensor in desired measurement zone; (2) Provide stable electrical connectivity between measurement zone and external control systems; (3) Provide protection from particulates and corrosive environment while giving access to species of interest (in the case of chemical sensors); (4) Provide EMI/noise shielding. The steps to achieve Phase I goals are as follows: (1) Refine the design of the integral probe; (2)Extend evaluation of alumina and mullite in diverse environments; (3) Extend evaluation of platinum, gold and AlTiN CrN as conductors and shields; (4) Fabricate complete probes, including samples chemical sensors; (5) Integrate signal transduction electronics and wireless interface; (6) Demonstrate design and materials in extensive lab and field tests at a local gasifier.