超临界和超超临界锅炉水冷壁的优化设计

阐述了超临界和超超临界锅炉水冷壁的优化设计，主要包括：下辐射区水冷壁采用内螺纹管，降低质量流速，准确掌握超临界流体热物性，减小工质焓增，减小热偏差和壁温偏差，降低局部热负荷，提高安全裕度等综合性措施。最低直流负荷优化选择综合考虑启动系统成本和变负荷运行范围以及对负荷快速变化的跟踪性能，以适应机组调峰。对1000MW超超临界锅炉垂直管屏水冷壁的流动特性进行了理论分析，强调应高度重视运行煤质变化的影响并严格监控水质。图5表1参7

Optimized Design of Water Walls of Supercritical and Ultra Supercritical Boilers

The following design details of supercritical and ultra supercritical boilers' water walls are being delineated: adoption of rifled tubes in the lower radiation zone's water wall,lowering the mass flow rate,well mastering the thermophysical characteristics of the supercritical fluid,reducing enthalpy increments of the working medium,diminishing the heat delivery and temperature deviations of the water walls,lowering local heat load,raising the safety margin,optimally selecting the minimal once-through circulation load by comprehensively considering expenditures required by the starting system,the load variation range as well as the load following capability during swift load variations,for meeting the set's cyclic operation requirements.A theoretical analysis of the medium's flow characteristics in the vertical water wall tubes of a 1000MW ultra supercritical boiler is being presented,pointing out that,during operation,much attention should be paid to the influence of coal quality variation and to the strict control of water quality.Tab.1,figs.5 and refs.7.