Development of Durable High-Temperature Catalysts for Natural Gas Combustion.Analysis of Heterogeneous Reactions, Heat Transfer, and Thermal Stresses in Combustion Catalyst Monoliths. Topical Report No. 4, July 1, 1991-February 28, 1994

摘要

The topical report describes the development of a numerical model for predictingthe transient performance and thermal stresses in combustion catalyst monoliths. The authors simulated the temperature and thermal stress distributions in a monolith during combustion of premixed methane and air at 10-atm. These simulations show that the high heat transfer coefficient at the entrance of a honeycomb channel leads to very high thermal stress during abrupt fuel cut-off and, surprisingly, during some catalyst 'light-off' conditions. Thermal conductivity along the substrate wall moderates the impact of transient cooling on therml stresses near the entrance. Very high temperatures are required before creep rates (in mullite) provide relief of residual stresses under long-term steady-state operation.