Optimization of Energy-saving Thermal Insulation Performance of High-temperature Steam Pipes in Thermal Power plants Based on Nanoporous Aerogel Superinsulation Technology

To address the significant heat loss issues in high-temperature steam pipes of thermal power plants, this study aims to optimize their energy-saving thermal insulation performance based on nanoporous aerogel super-insulation technology. Confronting the drawbacks of traditional materials like calcium silicate and rock wool, which include high thermal conductivity, bulky volume, and insufficient long-term reliability at temperatures above 600∘C, this paper innovatively proposes and designs a multi-layer composite insulation structure for application in 600∘C main steam pipelines. Through functional gradient design, this structure synergistically utilizes the Knudsen effect and nanoconfinement effect of nanoporous SiO2 aerogel felt to achieve an ultra-low equivalent thermal conductivity (as low as 0.0243 W/m⋅K at 650∘C), combined with the structural support of microporous calcium boards and the radiative reflection function of the outer cladding, thereby achieving multiple suppressions of gas-phase, solid-phase, and radiative heat transfer. The research comprehensively employs theoretical modeling, numerical simulation, and full-scale experimental validation. Results indicate that compared to traditional 100 mm calcium silicate insulation, the designed 80.5 mm composite structure reduces the average external surface temperature of the pipeline by 21.8% to 48.7∘C and decreases the surface heat flux density by 37.4% to 89.2 W/m2, equivalent to an annual saving of 2,528 tons of standard coal per single pipeline. Through coupled thermal-stress-fluid multiphysics field simulations and safety analysis, the structure is verified to have sufficient safety margins under thermal cycling, wind load, and manufacturing tolerances. Full-scale platform testing and long-term operational data further confirm the excellent stability of the system, with an annual thermal conductivity attenuation rate of only 4.2%, and the adoption of modular prefabricated construction shortens the project timeline by 31.2%. Although the initial investment increases by 50.8%, life cycle cost analysis shows a 28.8% reduction in total cost over 15 years, with a static payback period of approximately 1.2 years. This study provides an innovative solution for the energy-saving insulation of high-temperature steam pipes in thermal power plants, offering high performance, high reliability, and good economic benefits.