Steam Boilers' Advanced Constructive Solutions for the Ultra-supercritical Power Plants

摘要

This paper presents possible construction solutions to new steam boilers for ultra-supercritical power plants. At the current stage of development science and technology, one of the main problems with the transition to ultra-supercritical steam parameters is that a nickel-rich refractory and high temperature resistant steels and alloys prevail on weighting structure of materials for the ultra-supercritical power plants. Two advanced versions of boiler units' arrangement allowing to reduce the length of main steam piping and reheat piping are selected: horizontal and M-type. Optimal gas path geometry, arrangement of heating surfaces, slag removal system has been designed and the length of main steam piping and reheat piping has been estimated for the considered solutions. When passing to horizontal arrangement, the flow structure in boiler unit circuit changes significantly. Therefore, for the given version the extension study of furnace chamber aerodynamics, based on 3D modeling, was conducted. The burner units arrangement was developed as well as the ash hopper design that affects greatly aerodynamics. New power plant arrangement with horizontal steam boiler has been developed. If the solutions under consideration are used, the length of the main steam piping could be reduced from 150 m to 70 m compared to tower-type arrangement.