Catalytic Combustor Thermal Analysis

As part of a project for GRI (Gas Research Institute) to develop a thermomechanical and thermochemical analysis tool for combustion catalysts for a variety of natural gas combustion applications, we performed finite element calculations of thermal stresses in catalytic combustors. Figure 1 shows a finite element mesh of a honeycomb monolith catalytic combustor. During emergency cool down procedures these monoliths can experience thermal shock damage. Analytic expressions for the temperature distribution during cool down were developed and used as input for thermal stress calculations. Figure 2 shows the transient thermal stresses developed in the center plate of the catalytic combustor at a time of 2 s for cool down room temperature from a uniform operating temperature of 1100 degrees C. Tensile stresses develop along the outer edges of the plate which can lead to fracture. The results of these calculations showed that the temperature distribution at the start of cooling has a large effect on the thermal stresses developed during the cool down process.

Figure 1 Ceramic Catalyst Structure 3-Dimensional Finite Element Model
Figure 2 Calculated Thermal Stresses Longitudinal Stress Distribution Shown

Reference

• J. G. McCarty, D. M. Lowe, J. W. Simons, A. L. Florence, G. P. Smith," Development of Durable, High Temperature Catalysts for Natural Gas Combustion", SRI Progress Report to GRI, Contract No. 5091-260-2233, (Jan. 1993)

Contact Us
Don Shockey
Director, Center for Fracture Physics
Phone: 650-859-2587
Email: donald.shockey@sri.com