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国电泰州电厂的1 000 MW超超临界二次再热塔式锅炉为单炉膛布置。由于超超临界二次再热锅炉汽水流程复杂,工质温度水平较高,容易出现水冷壁超温现象。锅炉在低负荷运行时,省煤器出口工质欠焓减小,容易造成工质汽化以及流动不稳定现象。采用流动网络系统的水动力计算模型,对锅炉在不同负荷时上、下炉膛水冷壁出口汽温进行了计算,与实炉数据进行了比较,并对30%THA负荷进行了流动不稳定性校核。计算结果表明:100%负荷及75%负荷时,上、下炉膛水冷壁出口汽温运行偏差低于设计编差;施加热负荷扰动后流量在一定时间后能恢复稳定,锅炉水冷壁的运行是安全稳定的。由此表明所建立的1 000 MW超超临界二次再热塔式锅炉水动力计算模型和所开发的程序是可靠的,研究结果为超超临界二次再热锅炉设计提供了参考。 相似文献
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针对1 000 MW超超临界机组锅炉内螺纹管垂直管屏水冷壁变压运行特性进行了理论分析.重点分析了低质量流速下的水冷壁热偏差对流量偏差的影响关系和内螺纹管传热特性以及直流锅炉水冷壁强制流动特性被自然循环特性部分低偿的流动特性. 相似文献
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文章结合600MW超临界压力变压运行的垂直上升管圈水冷壁的设计实例.进行可行性的论证.论述和分析了水冷壁中质量流速和热负荷、水冷壁的水动力特性、相邻管间允许的工质温差和水冷壁的连接系统等问题.分析和计算表明:设计取用的额定负荷时的质量流速1929kg/m~2s能对水冷壁管起有效的冷却作用.无论是超临界压力或变压运行(系指在50~90%MCR负荷时变压运行),水动力特性是可靠的.超临界压力时没有传热恶化现象发生.运行在亚临界压力时,中辐射上部的偏差管虽可能发生膜态沸腾,但已避开最大热负荷区,最高管壁温度不超过412℃.没有停滞和倒流现象,水力偏差也不大. 相似文献
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1000MW超超临界锅炉水冷壁壁温计算 总被引:1,自引:0,他引:1
采用分区计算简化大容量高参数超超临界锅炉炉内辐射、对流传热模型,研究炉膛水冷壁热负荷及壁温的空间分布情况,并与试验数据进行了对比,计算结果与试验值之间的偏差较小,最大为5.72%.该模型与算法可给出不同锅炉负荷条件下,水冷壁壁面热负荷与壁温沿炉膛宽度方向的分布规律.结果表明,水冷壁热负荷与壁温均呈现出中间高两端低的弧形分布.四角切圆燃烧锅炉火焰位置对炉内传热有很大影响.模拟计算可为超超临界锅炉的运行提供参考,预测了在材料允许温度范围内,火焰中心偏斜最大不超过2 m. 相似文献
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Jie Pan Dong Yang Hui Yu Qin-cheng Bi Hong-yuan Hua Feng Gao Zhong-ming Yang 《Applied Thermal Engineering》2009,29(11-12):2500-2507
Water wall design is a key issue for an ultra supercritical boiler. In order to increase the steam–water mixture turbulization and to prevent the burnout of tubes walls, vertical rifled tubes are applied in Yuhuan power plant boiler which is the first 1000 MW ultra supercritical boiler in China and began to operate in December 2006. Mathematical modeling and thermal-hydraulic analysis are key factors for the successful design and operation of water walls. The water wall system is treated in this paper as a network consisting of circuits, pressure grids and connecting tubes. The mathematical model for predicting the mass flux distribution and metal temperature in water wall is based on the mass, momentum and energy conservation equations. An experiment on the heat transfer characteristics of vertical rifled tube was conducted with the aim to obtain the heat transfer performance and corresponding empirical correlations. The fitting computational formulas are applied in the mathematical model. The presented modeling method is more accurate than the conventional graphic method and can be applied to complex circuit structures. The mass flux distribution and the metal temperature in the water wall are calculated at 35%, 50% and 100% of the boiler maximum continuous rating (BMCR). The results show a good agreement with the plant data. The maximum relative difference between the calculated mass flux and the plant data is 9.7% at 50% BMCR load. The metal temperature difference in the tip of fins in lower circuit 8 is about 3–7 °C at 35% BMCR load. The results show that the vertical water wall in the ultra supercritical boiler of Yuhuan power plant can operate safely. 相似文献
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600MW超临界循环流化床锅炉水冷壁的选型及水动力研究 总被引:1,自引:0,他引:1
在超临界及亚临界压力范围内对不同尺寸的内螺纹管和光管的流动传热特性进行了实验研究,得到了偏离核态沸腾(DNB)和蒸干(DRYOUT)的发生规律、管子流动和传热的特性,建立了计算复杂流动网络系统回路流量及节点压力的数学模型,对非线性方程组采用迭代方法进行了求解,并对1台600 MW超临界循环流化床锅炉的水冷壁流量分配及壁温分布进行了计算.结果表明:在BMCR和在75%BMCR负荷下锅炉运行是安全可靠的.另外,笔者还研究了吸热偏差对流量分配及壁温分布的影响,结果表明流量与吸热量呈正响应特性. 相似文献
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900MW超临界塔式锅炉的技术特点 总被引:4,自引:0,他引:4
介绍了外高桥电厂二期900MW超临界塔式锅炉的基本情况。锅炉采用水平布置的对流受热面及螺旋水冷壁,能减少水冷壁的面积且受热均匀,可进行过热器及再热器的酸洗甚至取消冲管,有利于解决固体颗粒侵蚀(SPE)问题,对流受热面传热均匀且具有较高的传热利用系数和材料安全裕度,具有相当低的对流受热面磨损率和较低的烟风系统阻力,尤其是辐射(蒸发)和对流受热面比例的任意性,特别有利于高效超临界技术的发展。锅炉采用燃烧器分组,双一次风喷嘴和设置偏置风和燃尽风等技术,降低了燃烧中心温度峰值和NOX的生成,在降低燃烧区域热负荷的同时却提高了整个辐射受热面的平均热负荷,降低了水冷壁及炉膛出口的结焦风险。 相似文献
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For the purpose of disclosing the hydrodynamic flow characteristics, under the low mass velocity conditions of the 600-MW supercritical circular fluidized beds boilers, experimental studies on instability of two-phase flow in parallel vertical internally ribbed tubes were conducted. Two kinds of oscillations, pressure-drop oscillation and density-wave oscillation, have been observed. In the range of test parameters the effects of pressure, mass flux, inlet subcooling, compressible volume, exit throttle, and asymmetric heat flux to the two-phase instability were explored and analyzed. Indications from experiment data are: To increase system pressure, mass flux and inlet subcooling will intensify the stability of water wall tubes. To increase exit throttle will intensify the instability of water wall tubes. The bounding pressure and bounding mass flux of density-wave oscillations and the bounding pressure of pressure-drop oscillation have been obtained. Based on the results of testing and using a homogeneous model, the threshold relational expressions of instability were obtained. The results may be used for the design and safe operation of parallel vertical rifled water wall tubes of supercritical circular fluidized beds boilers. 相似文献
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超临界锅炉的汽温特性及控制 总被引:12,自引:0,他引:12
探索了几种超临界锅炉的汽温变化特性.根据实际数据获得了不同型式超临界锅炉过热器系统吸热量变化特性都是辐射特性的结论,并论证了此结论的合理性;分析了影响超临界锅炉汽温特性的几个主要因素;分析了1000 MW超超临界锅炉采用烟气挡板与摆动式燃烧器配合调温的技术优势;提出了超临界锅炉启动过程及变压运行各阶段汽温控制的要点. 相似文献
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阐述燃气-蒸汽联合循环启停操作过程中汽包壁温差大的现象,从余热锅炉汽包结构特点和启停过程 传热特性入手,详 热锅炉汽包 的原因,找到热锅炉负荷 汽包 大的 影
响因素。 运 优化操作包括 热锅炉汽包 、改汽包升温升 率、加快热锅炉
, 停 汽包上、下 大,对于优化余热锅炉启停操 制汽包上、下.差
的燃气 电厂有借鉴 。 相似文献
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Reza Baghaei Lakeh Adrienne S. Lavine H. Pirouz Kavehpour Gani B. Ganapathi Richard E. Wirz 《Numerical Heat Transfer, Part A: Applications》2013,63(12):955-973
Efficient heat transfer to storage fluid is required for the desirable operation of thermal energy storage systems. Most of the fluid candidates for supercritical thermal storage have poor thermal conductivity; therefore, conduction does not provide sufficient heat transfer. The current study concerns a supercritical thermal energy storage system consisting of horizontal tubes filled with a storage fluid in its supercritical state. The results of this study show that the heat transfer to the supercritical fluid is dominated by laminar and turbulent natural convection. The buoyancy-driven flow inside the storage tubes enhances the heat transfer and dramatically reduces the charge time. 相似文献
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采用选择性非催化还原脱硝技术的600 MW超超临界锅炉炉内过程的数值模拟 总被引:2,自引:0,他引:2
借助Fluent软件平台,对1台600 MW煤粉炉建立了数学模型,模拟了炉内流动、传热及燃烧过程.计算获得的炉膛出口平均烟温和烟气组分浓度与设计值符合良好,表明计算是合理的.采用三菱现代燃烧技术(MACT)燃烧技术和PM燃烧器使得NOx生成量较少,且一部分生成的NOx被还原,炉膛出口NOx浓度较低,为216 mg/kg,但可满足选择性非催化还原技术对初始NOx浓度的要求.根据选择性非催化还原反应的"温度窗"条件,适合进行选择性非催化还原脱硝反应的炉膛空间在标高为67m附近的区域,该区域内NOx总的分布规律是炉膛中心浓度低,壁面附近高,有利于采用还原剂从壁面喷射的方案. 相似文献