Economic analysis and cost modeling of supercritical CO2 coal-fired boiler based on global optimization

Abstract

Boiler is one of the critical equipment to realize supercritical carbon dioxide coal-fired (SCDC) power, but there is a lack of cost evaluation method. In this study, an improved global optimization model which is composed of genetic algorithm, thermal calculation and levelized cost of electricity (LCOE), was designed to obtain the optimal design of SCDC boilers. The cost curve of boilers with different capacity (350–1000 MW), temperature (600–650 °C) and pressure (300–330 bar) was analyzed and a new correlation of boiler cost was given. Due to the influence of heat transfer and material, the boiler cost firstly decreases and then increases with the increase of thermal power. For a single boiler, thermal power of 1000-2000 MWth is a suitable choice. Temperature affects boiler cost through thermal power and material strength, which are reflected by “r2t” and “r7t+r8“. Furthermore, double/multiple boiler design and positive matching principle were proposed to ensure the cost was in optimal range. These two schemes can provide the basis for selecting boiler parameters. The SCDC boiler cost increases by 32 % compared with the traditional steam boiler. SCDC units that meet the positive matching principle can achieve lower LCOE. This study can provide reference for the design of SCDC system.