Optimisation and thermo-mechanical analysis of a coated steam dual pipe system for use in advanced ultra-supercritical power plant

Abstract

Improving the energy efficiency of power plants by increasing steam operating temperature up to 700 °C can be achieved using novel engineering design concepts such as coated steam pipe systems. This paper presents an optimised design for a novel coated dual pipe system to be used in advanced ultra-supercritical power plant. The approach developed in this study uses a combination of an optimisation algorithm and FE simulation, based on the reduction of the hoop stress at top coat/bond coat interface generated by the thermal and mechanical stresses. This allows determination of the optimum dimensions and material properties of the system. A unified viscoplastic model which combines a power flow rule with non-linear anisothermal evolution of isotropic and kinematic hardening has been used for the thermo-mechanical analysis of the coated dual pipe system under the cyclic loading. The results of the optimisation show that the value of the hoop stress at the top coat/bond coat interface is reduced significantly, compared with that in the baseline model. Finally, the potential technical challenges and future works for the proposed steam dual pipe system are discussed.