Wireless embedded multi functional sensor system for in-situ health monitoring of refractory liners in fossil energy systems

Coal is the most abundant fossil fuel in the United States and accounts for greater share of energy production- Integrated gasification combined cycle (IGCC) is one of the promising technology used for the production electricity from fossil fuels- In an IGCC system, gasifier operates extreme high temperature (1375 - 1575 °C) and pressure (300- 1000 psi)- High chromium oxide (Cr2O3) refractory materials are used to protect the outer shell of the gasifier made of steel from extreme harsh environment- The molten slag interacts with the Cr2O3 refractory liner, causing refractory failure within 10 to 18 months by wear and corrosion- The replacement of refractory costs US$ 2,000,000 and three to four weeks of plant shutdown- Another major problem with IGCC system is the difficulty in measuring the operating temperature of gasifier- The currently used Pt-Pt/Rh thermocouples start malfunctioning within few weeks due to the corrosion caused by the molten slag penetrated through the access port- Accurate measurement of temperature is critical in a gasifier because high gasification temperature accelerates slag flow causing refractory wear and shortening of the life whereas low gasification temperature increase viscosity of slag and disrupt the flow resulting gasifier shutdown and economic losses- We propose to demonstrate through this project that temperature and degradation of Cr2O3 refractory in a gasifier can be monitored in-situ by embedding temperature and spallation sensors within the refractory bricks- Such capabilities are very useful for improving the efficiency of gasifier and planning the maintenance schedule well in advance to minimize the economic loss- This proposal seeks to achieve the following specific objectives: (1) Synthesis a broad composition range of inter-metallic silicide powder compositions of Mo(Si1- XAlX)2 and W(Si1-XAlX)2 by self-propagating high temperature synthesis (SHS) route and select the optimum composition based on characterization results, (2) pattern the temperature and spallation sensors using the optimum power composition on alumina substrate by tape casting and laser cut method, (3) laminate the sensors with functionally graded layers of Al2O3-Cr2O3 composites to prevent the reaction between sensors and Cr2O3 brick at high temperature, (4) fabricate a prototype by embedding the laminated sensors within high-chromia green brick, (5) interface the sensor output with wireless network to transmit the data to processing unit- In the second phase of this project heath of the refractories will be estimated by model based approach-