The high-temperature sulfur corrosion resistance of S30432 and TP310HCbN typically used in the superheater and reheater of a 620 degrees C ultra-supercritical boiler is investigated in this study. Samples coated with coal ash are placed in a device filled with simulated flue gas at 650 degrees C and 700 degrees C, respectively, for 2000 h. The samples are then analyzed through X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. S30432 is mainly oxidized under 650 degrees C and 0.2% SO2 volume concentration, and the weight reduction is 6.6 mg cm(-2). However, under 700 degrees C and 0.3% SO2 volume concentration, severe sulfidation reaction occurs, sharply accelerating high-temperature corrosion. As a result, weight reduction up to 41.8 mg cm(-2) occurs. Although sulfidation reaction also occurs in TP310HCbN, there is no serious corrosion; the corrosion rate reduces in the later stages of the experiment, and a weight increase of 2.4 mg cm(-2) is observed. After 11 520 h of the actual operation of the 1000 MW 620 degrees C boiler, there is no obvious high-temperature corrosion in the high-temperature areas without coke-block adhesion. These results indicate that S30432 and TP310HCbN satisfy the requirements of 620 degrees C ultra-supercritical boilers burning high-sulfur coal.

Wall temperature of heat transfer tubes is one of the most important parameters indicating the operation safety of various heat transfer facilities, and as a result, estimation of the wall temperature becomes one of the main tasks in the design of heat transfer facilities. The wall temperature look-up table (Tw-LUT) can be established directly from experimental data and can be then used to estimate the wall temperature of the heat transfer tubes, avoiding the approximation or extrapolation of fluid properties that inevitably exists in the heat transfer correlations. In view of the problems existing in applications with wall temperature estimations of the heat transfer tube, such as limited data points and the limited application scopes of parameters, a look-up table is built in this paper for wall temperatures of vertically-upward round tubes of 10 mm tube diameter with heat transfer to supercritical water (SCW), under conditions with pressure in the range from 22.5 to 31 MPa, the mass velocity in the range from 200 to 3000 kg.m(-2).s(-1), the heat flux in the range from 200 to 1800 kW.m(-2), and the bulk fluid enthalpy in the range from 1000 to 3000 kJ.kg(-1). In order to cover the gaps between the experimental data points, and to improve the prediction accuracy of the Tw-LUT, the best heat transfer correlation is selected for each local area of interest in the LUT based on its prediction accuracy in the corresponding local area, and then the best heat transfer correlation is adopted to supplement wall temperature results to fill up the Tw-LUT. The comparison between the wall temperatures by the Tw-LUT and the experimental wall temperatures is carried out to verify the accuracy of the Tw-LUT, and it is shown that the mean absolute deviation of the results is 0.87%, and 87.81% of the results fall into the +/- 3% error band, indicating that the Tw-LUT has a good accuracy for wall temperature prediction and the establishment method is reliable and can be used to build other look-up tables. The Tw-LUT can be applied not only to normal heat transfer conditions but also to deteriorated heat transfer conditions and enhanced heat transfer conditions with a satisfactory accuracy.

700℃等级高效超超临界燃煤发电技术具有高效、节能和环保等特点，是我国未来火力发电的重要方向之一。超临界锅炉的水冷壁设计是超临界火力发电机组开发的关键技术之一。本课题设计并搭建了高参数超临界水的流动与传热实验平台(设计压力42 MPa,设计温度760℃);在该实验平台上开展了高参数超临界水的流动换热特性实验研究，实验最高运行压力38 MPa,最高工质温度750℃,获得了高参数超临界水在垂直上升管内的流动换热的大量数据；建立了竖直上升光管内超临界水流动换热及摩擦阻力的数据库，并提出了垂直上升管内超临界水流动传热的传热系数和摩擦阻力系数的新的计算关联式。对700°C超超临界工质的流动与换热的动态特性、水动力不稳定性开展研究，掌握了其基本变化规律。基于流动网络系统法，研发出适用于700℃超超临界锅炉的水动力计算程序，与同类型已投运的超超临界锅炉实炉测量结果及国外同类软件的计算值进行了比较，结果表明管屏出口温度偏差的计算精度≤10%。对三种典型结构的700℃超超临界锅炉的总体布置方案、水循环系统流程、水动力设计与优化技术等开展研究。利用本项目开发的水动力计算程序，对各个锅炉方案的水动力特性进行了计算分析，得出了在锅炉最大连续蒸发量(BMCR)、50%BMCR和30%BMCR负荷时的水冷壁压降、流量分配、炉膛出口工质温度分布及壁温沿炉膛高度方向的变化趋势，论证了各负荷条件下锅炉水冷壁工作的可靠性。The Ultra-Supercritical Pressure Electricity Production Technology with 700℃ Steam Temperature(USP-EPT700)is one of the most promising technologies,which can be applied in coal-fired thermal power plants in the coming future.In order to provide some basic support for the development of USP-EPT700 technology,a new ultra-supercritical pressure and high temperature experimental facility is designed and fabricated,and a series of experiments are carried out on the new facility to study the flow and heat transfer characteristics of water flowing in vertically upward tubes at pressures up to 38MPa and temperatures high than 750℃,and a large number experimental data regarding the heat transfer and pressure drops of water are obtained.In combination with the relevent data retrieved from related literatures,a database is established for the heat transfer and pressure drop of supercritical water in vertically upward tubes,and new correlations for prediction of the heat transfer coefficients and frictional pressure drop coefficients of supercritical pressure water are formulated.Besides,the transient flow and heat transfer,and also the flow instability of supercritical pressure water in tubes,are studied to learn the characteristics of the related phenomena.In order to achieve reliable operation of 700℃ ultra-supercritical boilers,a hydrodynamic calculation program is developed based on the nonlinear flow network model,and can be used for hydrodynamic analysis of 700℃ ultra-supercritical boilers.Hydrodynamic calculations are performed by using this program,and the calculation results are compared with actual operation recordings of similar boilers in practical power plants,and also with the calculation results of other similar codes developed by foreign groups,to verify the reliability of the program.It is shown that the maximum bias in steam temperature at the outlet of heat transfer tubes in a typical boiler tube panel is within 10%.Moreover,three typical but different layouts of 700℃ ultra-supercritical boilers are proposed and designed,and hydrodynamic calculations are performed for each of the three newly-developed 700℃ ultra-supercritical boiler layouts,and the water-cooled wall pressure drop,flow distributions among tubes in boiler panels,fluid temperature distributions along the furnace height,and steam temperature distributons at the outlet of the furnace are calculated,respectively,at the 100%BMCR,50%BMCR and 30%BMCR loads.

本年度建立了超高参数运行条件下工质流动与传热数据库框架，参数范围：压力10-35 MPa,温度100-600℃,采用查询表方法可准确预测不同工况条件下的壁面温度。完成实验平台中设备的购置，初步完成实验平台的搭建;开发了基于流动网络系统方法的700℃超超临界锅炉水冷壁设计及水动力特性集成计算技术，并进行水动力安全特性校核，程序计算的壁温分布与电厂数据变化趋势相同，且吻合良好，实现管屏出口温度偏差的计算精度≤10%;针对提出的700℃卧式锅炉，建立水动力与壁温计算模型，对该参数下的锅炉展开炉膛燃烧数值模拟与水动力计算与分析，分析结果表明锅炉设计中受热面和阻力件布置合理。进一步对700℃参数超超临界型对冲燃烧锅炉布置方案进行了优化计算；结合700℃超超临界参数情况及塔式锅炉特点，确定了水冷系统布置规格及材料的选择；完成适合700℃超超临界燃煤锅炉汽水循环系统设计和系统选型研究，先进的水冷壁中间混合系统，提高管间壁温均匀性，提高水冷壁的运行安全性。In this year,a database framework for working fluid flow and heat transfer under ultra-high operating conditions has been established.The parameters range from 10 to 35 MPa and 100 to 600 ℃.The wall temperature under different working conditions can be accurately predicted by the look-up table method.The purchase of equipment for the experimental platform is completed and the construction of the experimental platform is basically completed.Based on the flow network system method,the water wall design and integrated calculation technology for hydrodynamic characteristics of 700 ℃ ultra-supercritical boiler has been developed,and the verification of hydrodynamic safety characteristics was carried out.The trend of wall temperature distribution calculated by the program is almost the same as that of the power plant data,and it was in good agreement.The calculation accuracy of the tube panels outlet temperature deviation is less than 10 percent.A calculation model of hydrodynamics and wall temperature is established for 700 ℃ horizontal boiler,and the numerical simulation,hydrodynamic calculation and analysis are carried out.The analysis results show that the heating surface and the resistance part are well arranged in the boiler design.Furthermore,the layout scheme of 700 ℃ ultra-supercritical PI-type counter-fired boiler is optimized.According to the characteristics of Tower Boiler and the condition of 700℃ ultra-supercritical parameters,the water cooling system layout and material are determined.The design and selection of the steam-water circulation system for 700°C ultra-supercritical coal-fired boilers are completed.An advanced water-cooled wall mixing system is designed to improve the uniformity of wall temperature between the tubes and the operational safety of the water wall.

课题形成了超临界工质流动与传热、动态特性与水动力计算最新研究成果调研，建立数据库框架，参数范围：压力10-35 MPa,温度100-600℃,采用查询表方法准确预测了不同工况条件下的壁面温度；完成超高参数超临界水流动与传热实验平台的整体设计，完成实验平台中设备的购置；针对700℃超超临界锅炉布置方案，开发基于流动网络系统方法的700℃超超临界锅炉水冷壁设计及水动力特性集成计算技术，并进行了水动力安全特性校核，程序计算的壁温分布与电厂数据吻合良好，实现管屏出口温度偏差的计算精度≤10%的指标要求；针对新提出的700℃卧式锅炉，建立了水动力与壁温计算模型，对该参数下的锅炉展开炉膛燃烧数值模拟与水动力计算与分析，结果显示卧式锅炉设计中的受热面和阻力件布置合理；完成700℃参数超超临界型对冲燃烧锅炉初步整体布置方案，确定炉膛尺寸及受热面的布置，并进行热力计算，确定水冷壁进出口参数；结合700℃超超临界参数情况及塔式锅炉特点，提出超临界塔式锅炉水冷系统初步的方案；针对700℃超超临界型切圆锅炉，根据初步660MW,700℃超超临界汽机热平衡图，完成汽水参数计算和初步热力计算，形成热力计算汇总资料和初步总体布置图，完成锅炉整体方案布置和基本性能计算；完成适合700℃超超临界燃煤锅炉汽水循环系统设计和系统选型研究，先进的水冷壁中间混合系统，提高管间壁温均匀性，提高水冷壁的运行安全性。The subject formed a research report on the latest research of flow and heat transfer of supercritical fluid,dynamic characteristics and hydrodynamic,and established a database framework with parameters ranging in 10-35 MPa and 100-600 °C,using the lookup table method to accurately predict the wall temperature under any working conditions.The overall design of ultra-high parameters supercritical water flow and heat transfer experimental platform and the equipments used in such platform were deployed.A mobile network system for 700 °C ultra-supercritical boiler layout was developed.The design of 700 °C ultra-supercritical boiler water wall and its hydrodynamic characteristics was integrated,the hydrodynamic safety was carefully checked,the calculated wall temperature is in good agreement with the measurement data in the power plant,and the calculation accuracy of the outlet temperature deviation is lower than 10%.Moreover,a hydrodynamic and wall temperature calculation model was established for the newly proposed 700°C horizontal boiler,numerical simulation and hydrodynamic analysis of the furnace combustion were carried out.The results showed that the heating surface and the resistance part of the horizontal boiler are arranged reasonably.Some preliminary calculations of the 700 °C ultra supercritical boiler is completed.The body layout scheme determines based on the size of the furnace and the arrangement of the heating surface.For 700 °C ultra supercritical tower boiler,a preliminary scheme for the water cooling system of the supercritical tower boiler is proposed.Based on the ultra-supercritical turbine heat balance diagram,steam water parameters and preliminary thermal calculation,the thermal calculation summary data and the preliminary overall layout diagram were formed,the overall scheme of the boiler arrangement and basic performance calculation,the design and system selection of steam water circulation system also were completed.