锅炉出口烟温偏差分析及纠正

讨论了四角切圆燃烧锅炉炉膛出口烟温偏差的原因,提出了消除偏差措施的设想。     

Ⅱ型布置切圆燃烧锅炉超大型化发展的一些动向及分析展望 --介绍一种新的单炉膛双切圆燃烧方式

通过对国外切圆燃烧锅炉超大型化后炉型发展的分析,指出燃烧器布置由简单的四角切圆变化到无双面水冷壁型的单炉膛双切圆布置是一明显的发展趋势.阐述单炉膛双切圆燃烧锅炉解决烟温偏差的理论构想,分析其对大型化锅炉燃烧贫煤的适应性,并对单炉膛双切圆燃烧系统若干问题进行了讨论,认为600MW燃贫煤锅炉应优先考虑采用单炉膛双切圆燃烧这一方式.     

∏型布置切圆燃烧锅炉超大型化发展的一些动向及分析展望——介绍一种新的单炉膛双切圆燃烧方式

通过对国外切圆燃烧锅炉超大型化后炉型发展的分析,指出燃烧器布置由简单的四角切圆变化到无双面水冷壁型的单炉膛双切圆布置是一明显的发展趋势。阐述单炉膛双切圆燃烧锅炉解决烟温偏差的理论构想,分析其对大型化锅炉燃烧贫煤的适应性,并对单炉膛双切圆燃烧系统若干问题进行了讨论,认为600MW燃贫煤锅炉应优先考虑采用单炉膛双切圆燃烧这一方式。     

同心反切燃烧锅炉四角配风不均对炉内多相流动的影响

四角切圆燃烧锅炉中各角一、二次风风速均衡是提高锅炉燃烧效率 ,防止炉内火焰中心偏移、炉膛结渣的重要因素。但大容量锅炉多采用直吹式制粉系统 ,且送粉管道阻力不均 ,燃烧器数量众多 ,易发生配风不均。采用数值模拟方法对采用同心反切二次风系统的某 3 0 0MW四角切圆燃烧锅炉四角配风不均对炉内多相流动特性进行了多工况模拟。获得了配风不均对炉内切圆中心、颗粒运动轨迹、贴壁风速等的影响。同时就配风不均对采用同心反切二次风系统和不采用二次风反切技术的四角燃烧系统的影响进行了比较 ,结果表明 ,采用同心反切系统的四角燃烧锅炉对配风偏差更为敏感 ,应引起设计和运行人员的注意     

660 MW超超临界锅炉火焰偏斜调整方法浅析

某公司超超临界660 MW机组四角切圆锅炉由于设计、安装等原因,运行中出现燃烧火焰偏斜问题,水冷壁壁温左右侧偏差达到80℃,后屏出口蒸汽温度左右侧偏差达到60℃,主、再汽温左右侧偏差达到15℃,严重影响机组运行的安全性、经济性。基于对660 MW四角切圆锅炉燃烧调整方法的分析与总结,纠正了火焰中心偏斜,消除了水冷壁壁温偏差和汽温偏差,优于设计值,确保了锅炉安全运行。     

四角切圆燃烧方式锅炉水平烟道中的烟气偏差

本文根据试验和调研资料的统计叙述了大容量四角切圆燃烧锅炉水平烟道烟气偏差的特点、形成原因，并提出了相应的解决措施。     

反向OFA对减少锅炉烟温偏差作用的分析

通过锅炉燃烧器具体试验,分析证明了燃烧器顶部布置反向OFA是一种有效减少四角切圆燃烧残余旋转引起的烟温偏差的方法。     

切圆燃烧流场中不同高宽比矩形喷嘴射流特性的试验研究

采用热线风速仪,首次在四角切圆燃烧的流场中,对不同高宽比的一次风矩形喷射流在流场中的刚性及湍流特性进行了详细的试验研究,并分析了在不同高宽比下矩形喷嘴射流在四角切圆复杂流场中的偏转及稳燃机理,得到了的四角切圆燃烧流场中一次风矩形喷嘴的最佳高宽比,对工程设计及应用都有较好的参考价值。     

四角切圆燃烧锅炉折焰角结构分析

四角切圆燃烧方式在炉膛出口处普遍存在气流残余旋转。作者讨论了四角切圆燃烧方式下折焰角结构上的缺陷，并提高了异型结构的折焰角形式，在减小气流残余旋转方面有明显效果。采用新型的“混合”差分格式（ＱＵＩＣＫＥＲ和上风）对实炉进行了数值模拟。     

1000MW单炉膛双切圆锅炉烟温偏差调整

锅炉炉膛出口烟温偏差会引起受热面壁温偏差,主、再热汽温不平衡等一系列的锅炉运行问题,尤其是采用单炉膛双切圆的燃烧方式,左右两个切圆的相互扰动会比单切圆的燃烧方式更容易产生烟温偏差,本文针对在锅炉实际运行过程中出现的该类问题进行分析,并提出解决方案,为以后的锅炉燃烧调整时出现烟温偏差的处理提供参考。     

大型锅炉水平烟道左右两侧烟温偏差的研究

在我国火电站现用的许多大型４角切圆燃烧锅炉中，存在着水平烟道两侧烟温差的问题，由此产生过热器和再热器超温过热。为了提高其安全可靠性，本文讨论了这种烟温差的影响因素，并对一台１０２５ｔ／ｈ４角切向燃烧锅炉进行了现场试验研究，测定了锅炉水平烟道的两侧速度偏差。并由此计算了两侧的烟温和管壁温度偏差。研究结果表明：该锅炉燃烧器采用３次风反切，对于减少这种烟温差是很有效的。     

基于BP神经网络的黄河中上游河段不平衡水量预测

针对黄河水量统一调度工作中,中上游河段出现的水量不平衡问题,以刘家峡—头道拐河段为例,采用水量平衡公式计算1999~2012年刘家峡—头道拐河段的不平衡水量,并运用BP神经网络技术和方法研究了刘家峡—头道拐河段不平衡水量的变化规律,预测了刘家峡—头道拐河段的不平衡水量。结果表明,BP神经网络模型预测效果较好、精度较高。     

转子大不平衡振动的研究

为使轴系破坏事故调查、寻找转子大不平衡振动摆脱困境,历经近20年的研究,查明了引起轴系破坏的转子各种大不平衡振动原因及形成机理。在阐述研究结果的同时,分析了国内5起破坏原因最为复杂的毁机事故。研究结果表明,造成轴系破坏的大不平衡振动原因有,转动部件飞脱、转轴碰磨、转轴刚度降低、扭矩冲击,其中转动部件飞脱引起的瞬态响应和扭矩冲击产生的大不平衡振动造成毁机事故机理,在国内外尚属首次提出。对查明轴系破坏真正原因和提高机组振动故障诊断水平有较大的帮助。     

Insurance strategy for mitigating power system operational risk introduced by wind power forecasting uncertainty

The increasing penetration of wind power significantly affects the reliability of power systems due to its intrinsic intermittency. Wind generators participating in electricity markets will encounter operational risk (i.e. imbalance cost) under current trading mechanism. The imbalance cost arises from the service for mitigating supply-demand imbalance caused by inaccurate wind forecasts. In this paper, an insurance strategy is proposed to cover the possible imbalance cost that wind power producers may incur. First of all, a novel method based on Monte Carlo simulations is proposed to estimate insurance premiums. The impacts of insurance excesses on premiums are analyzed as well. Energy storage system (ESS) is then discussed as an alternative approach to balancing small wind power forecasting errors, whose loss claims would be blocked by insurance excesses. Finally, the ESS and insurance policy are combined together to mitigate the imbalance risks of trading wind power in real-time markets. With the proposed approach, the most economic power capacity of ESS can be determined under different excess scenarios. Case studies prove that the proposed ESS plus insurance strategy is a promising risk aversion approach for trading wind power in real-time electricity markets.     

非全线同塔双回架设的1000kV换位线路电流不平衡度研究

在地形复杂或覆冰较严重处,输电线路无法采用全线同塔双回的方式架设,而采用并行单回架设的线路段时需研究其对全线三相电流不平衡的影响。对此,在推导电流不平衡度计算方法的基础上,通过ATPEMTP仿真建模计算,研究了有一个整循环换位的1 000kV双回分段架设线路中相序排列、换位方式及单回线路段的首尾连接方式、回间距离等因素对电流不平衡度的影响,得出了较优的换位、相序排列组合方案及单回线路段连接方式,并总结了单回线路段的回间距离对线路电流不平衡度的影响规律,对改善实际非全线同塔双回架设的线路中出现的电流不平衡问题有参考意义。     

基于双电池不平衡状态优化的风功率平滑控制

在双电池平滑风功率过程中,改善双电池充放电不平衡状态可以提高充放电深度,减少充放电状态切换次数。文章分析了双电池风功率平滑系统的充放电不平衡状态及其产生的原因,提出了一种改进控制策略,该策略可根据双电池荷电状态调整风功率平抑目标功率,以此改善双电池不平衡状态。基于Matlab/Simulink分析了风速湍流强度以及风功率预测误差对双电池不平衡状态的影响,同时验证了改进控制策略的有效性和优越性。研究结果表明,相较于传统控制策略,文中的改进控制策略在不同湍流风速以及存在风功率预测误差时,仍能优化双电池充放电不平衡状态,保持良好的充放电深度。     

Impact of wind power on the power system imbalances in Finland

A study on the imbalance costs or payments that wind power producers pay on the one hand and the cost incurred for the power system on the other hand is presented. Both the producer side and the system side will be examined with case data on prediction errors, system net imbalances and the balancing costs. The upscaled forecast errors of wind power that result in imbalances have been combined with the system real net imbalance. Comparisons and discussion about the balancing costs of wind power depending on the wind penetration are provided. The results for Finland show that a two-price system for imbalances results in higher imbalance costs than a one-price system. At low wind power penetration levels, the difference in imbalance payments is high for one- and two-price system. When wind penetration increases, there is not so much difference in the different balance settlement rules used. According to the comparison between imbalance payments and system costs, the increase in system costs because of wind power is lower than imbalance payments for wind power producers when using either average prices for up- and down-regulation or the regulation prices that increase linearly with regulation demand.     

Energy perspective of Sino-US trade imbalance in global supply chains

The unprecedented global supply chain fragmentation brings an ever-increasing trade imbalance in terms of monetary flows between China and the United States. Associated with the bilateral trade imbalance is the reallocation of resources utilization and environmental stress. In this regard, this study presents an embodied energy model to investigate impacts of Sino-US trade imbalance on global energy use during 2000–2014. Distinguished from previous studies that only evaluate the Sino-US trade based on specific bilateral perspective, this study probes into overall impacts of the Sino-US trade on global primary energy use pattern from the perspective of global supply chains for the first time. A boost to eastbound trade and distinct export industrial structures fuel the unprecedented growth of Sino-US embodied energy trade imbalance, accounting for more than half of the total energy transfers embodied in Sino-US trade. Such imbalance firstly increases sharply from 1956.0 PJ in 2000 to 5265.3 PJ in 2006, followed by a short term decrease to hit a low point at 3267.7 PJ in 2009 because of financial crisis and then a gradual resuscitation with a slower pace in the following years. The exported energy embodied in manufacturing products dominates eastbound flows, whereas energy embodied in agricultural products, technology intensive products and primary energy commodities constitute majority of westbound flows. Due to the dispersed production process in global value chains, more than half of primary energy use embodied in the bilateral trade is geographically exploited in other economies along the supply chain (i.e., Europe, the Middle East and South Asia). Furthermore, security of energy supply is evaluated for the two economies. The results can help predict potential influences of trade conflicts on global energy extraction, illustrating policy implications to make Sino-US trade in line with global energy conservation goals. Considering Sino-US trade's impacts along complex supply chains, distinctive domestic energy conservation measures should give way to global collective and inclusive governance.     

Performance characteristics of a miniaturised chemical looping steam reformer for hydrogen enrichment of fuels

A miniaturised chemical looping steam reformer (μ-CLSR) is being developed at the University of Newcastle (Australia) for onboard hydrogen enrichment of fuels in internal combustion engines. Experimental results from the first prototype highlighted an imbalance between the rates of redox reactions. A new configuration has been developed to resolve this shortcoming. The objective of this study is to examine the effectiveness of the new configuration in handling the imbalance between redox rates. Experiments were conducted on magnetite and wuestite metal oxides under methane and steam environments in the new configuration. Results indicate that if micro-reactors within the reformer are operated in parallel during the oxidation half cycle and in sequence during the reduction half cycle, the imbalance can be effectively managed. This combined with manifold switching of reacting gases at 48 s intervals enables metal oxides to achieve a 30% fractional conversion at 900 °C; resulting in a product gas stream with 96% H₂ purity.     

600MW超临界机组转子不平衡故障分析与处理

分析了质量不平衡故障机理、原因和振动特征,针对某电厂2号600 MW超临界机组9号瓦及1号瓦轴振大的问题,进行了测试和分析,判断1号、9号轴瓦轴振大为不平衡量增大所致,分析了引起不平衡的原因。根据诊断结果,对1号、9号轴瓦进行了动平衡和抽高中压转子返厂处理。并与同类故障进行比较,给今后相似故障的分析处理提供参考。