Multidisciplinary materials and geometry optimization of superheater tubes for advanced ultra-supercritical power boilers

The recent development of the coal-fired power plant purposes to enhance environmental-friendliness and efficiency. In order to achieve these goals, many research studies are underway to develop advanced ultra-supercritical (A-USC) boilers, which requires materials that can withstand extreme conditions. Integrated materials and product design (IMPD) is a new approach for designing products able to yield effective operation in extreme conditions. Based on the IMPD approach, we optimized the geometry of the superheater tube of the A-USC boiler as well as its constituent materials. To apply the IMPD to the tube design problem, we developed a creep deformation model based on finite element analysis, a heat transfer model, and two material models constructed via artificial neural networks. The material models predict creep properties and thermal conductivity for a given heat treatment condition and weight ratio of the chemical constituents. These four models are used in combination to form an analysis model chain, which is subsequently incorporated into an optimization routine for finding optimum material constituents and shapes of the superheater tube at the same time. An optimal tube design was developed to achieve minimum creep deformation and maximum heat transfer amount under the stringent operating conditions of the A-USC boiler.