A novel carbon trap sampling system for coal-fired flue gas mercury measurement

A novel carbon trap sampling system for gas-phase mercury measurement in flue gas is developed, including the high efficient sorbents made of modified biomass cokes and high precision sorbent traps for measuring particle-bound and total vapor-phase mercury in flue gas. A dedusting device is installed to collect fine fly ash for reducing the measurement errors. The thorough comparison test of mercury concentration in flue gas is conducted between the novel sampling system and the Ontario hydro method （OHM） in a 6 kW circulating fluidized bed combustor. Mercury mass balance rates of the OHM range from 95.47% to 104.72%. The mercury breakthrough rates for the second section of the sorbent trap are all below 2%. The relative deviations in the two test cases are in the range of 15. 96% to 17. 56% under different conditions. The verified data suggest that this novel carbon trap sampling system can meet the standards of quality assurance and quality control required by EPA Method 30B and can be applied to the coal-fired flue gas mercury sampling system.

Optimization of Minimum Power Output for Combined Heat and Power Units Considering Peak Load Regulation Ability

Northern China has rich wind power and photovoltaic renewable resources. Combined Heat and Power (CHP) Units to meet the load demand and limit its peaking capacity in winter, to a certain extent, it results in structural problems of wind-solar power and thermoelectric. To solve these problems, this paper proposes a plurality of units together to ensure supply of heat load on the premise, by building a thermoelectric power peaking considering thermal load unit group dynamic scheduling model, to achieve the potential of different thermoelectric properties peaking units of the excavation. Simulation examples show, if the unit group exists obvious relationship thermoelectric individual differences, the thermal load dynamic scheduling can be more significantly improved overall performance peaking unit group, effectively increase clean energy consumptive.

Aggregator-based demand response mechanism for electric vehicles participating in peak regulation in valley time of receiving-end power grid

With the increase in the power receiving proportion and an insufficient peak regulation capacity of the local units, the receiving-end power grid struggles to achieve peak regulation in valley time. To solve this problem while considering the potential of the large-scale charge load of electric vehicles(EVs), an aggregator-based demand response(DR) mechanism for EVs that are participating in the peak regulation in valley time is proposed in this study. In this aggregator-based DR mechanism, the profits for the power grid’s operation and the participation willingness of the EV owners are considered. Based on the characteristics of the EV charging process and the day-ahead unit generation scheduling, a rolling unit commitment model with the DR is established to maximize the social welfare. In addition, to improve the efficiency of the optimization problem solving process and to achieve communication between the independent system operator(ISO) and the aggregators, the clustering algorithm is utilized to extract typical EV charging patterns. Finally, the feasibility and benefits of the aggregator-based DR mechanism for saving the costs and reducing the peak-valley difference of the receiving-end power grid are verified through case studies.

Role of optimal transmission switching in accommodating renewable energy in deep peak regulation-enabled power systems

Due to the shortage of fossil energy and the pollution caused by combustion of fossil fuels,the proportion of renewable energy in power systems is gradually increasing across the world.Accordingly,the capacity of power systems to accommodate renewable energy must be improved.However,integration of a large amount of renewable energy into power grids may result in network congestion.Hence,in this study,optimal transmission switching(OTS)is considered as an important method of accommodating renewable energy.It is incorporated into the operation of a power grid along with deep peak regulation of thermal power units,forming an interactive mode of coordinated operation of source and network.A stochastic unit commitment model consider!ng deep peak regulation and OTS is established,and the role of OTS in promoting the accommodation of renewable energy is analyzed quantitatively.The results of case studies involving the IEEE 30-bus system demonstrate that OTS can enable utilization of the potential of deep peak regulation and facilitate the accommodation of renewable energy.

Estimation of Unit Flood Discharge for Various Land Use Types with a Focus on Urbanization

We proposed unit flood discharge model that defined as the discharge into end-order (smallest) drainage canals. The discharge acts an important role for estimating regional flooding by big rainfall events which leading roughly estimation of flood discharge associated with land use changes as urbanization. In some areas of Japan, increased urbanization with insufficient drainage canal capacity has led to increasingly frequent flooding and flood damage. The aim of this study was to investigate the effect of urbanization on unit flood discharge using a runoff model for the Tedori River alluvial fan area, Japan. The discharge was studied as collecting runoff from paddy fields, upland crop fields, and residential lots. A runoff model for various land use types in the study area was developed using actual and physical properties of the runoff sites, and parameters for paddy fields. The model was tested using 54 big events and inputted those. The maximum total runoff ratio among different land use types was observed for residential lots, and the ratio remained relatively constant across different flood events. The minimum total runoff ratio was observed for irrigated paddy fields. There was a positive relationship between the total runoff ratio and total precipitation for all land use types. Whereas, the relationship between the peak runoff ratio and peak precipitation was variable. The runoff analysis was carried out using 60-min and 10-min precipitation data. For agricultural land, data for both intervals produced similar results.

Time Step Issue in Unit Hydrograph for Improving Runoff Prediction in Small Catchments

Unit hydrograph is a very practical tool in runoff prediction which has been used since decades ago and to date it remains useful. Unit hydrograph method is applied in Way Kuala Garuntang, an ungauged catchment in Lampung Province, Indonesia. To derive an observed unit hydrograph it requires rainfall and water level data with fine time scale which are obtained from automatic gauges. Observed unit hydrograph has an advantage that it is possible to derive it for various time steps including those with time step less than an hour. In order to get a more accurate unit hydrograph, it is necessary to derive a unit hydrograph with small time step for a small catchment such as those used in this study. The study area includes Way Kuala Garuntang and its tributaries, i.e. Way Simpur, Way Awi with areas are 60.52 km2, 3.691 km2, and 9.846 km2 respectively. The results of this study highlight the importance of time step selection on unit hydrograph, which are shown to have a significant impact on the resulting unit hydrograph’s variables such as peak discharge and time to peak.

Effect of Flood Peak Discharge Control by a Small Reservoir in an Urbanized Area—Case Study in the Kurabe River Basin, Japan

Recently severe damage of flooding by urbanization was frequently occurred. To prevent this damage, small reservoir was constructed in the urbanized residential area. This paper describes an effect of flood peak discharge control by a small reservoir (control reservoir) caused by rapidly developed urbanization. Although work for this purpose was conducted, research on the effects of the control reservoir was not conducted until now. This research, conducted by simulation, was a case study in the Kurabe River Basin in the Tedori River Alluvial Fan Area, Japan, based on the precise investigation of the reservoir in the actual field. The study was conducted to determine not only the actual control reservoir capacity for the newly developed residential area but also the ideal capacity for all present residential areas and the largest capacity allowable for a maximum rainfall event that recently occurred. The control reservoir effects between individual blocks and the entire basin area were compared by dividing the test basin into 15 blocks (sub-basins). The results showed that the effects on the capacity per unit area of the residential area in blocks have close relationship with the decreasing ratio of peak discharge in blocks. Consequently, the effects of control reservoir capacity and the limitation were clarified. In the future, control reservoirs should be constructed for all of the already developed residential areas, for example, by utilizing underground car parking lot. The results of this research can contribute to the design of the control reservoir for protection against flooding damage in urbanized areas.

The Effects of SO_3 in Flue Gas on the Operation of Coalfired Units and Countermeasures

There exists a certain amount of SO_3 in flue gas discharged from coal-fired power plants. With the operation of the selective catalystic reduction( SCR) denitrification system,SO_3 concentration in the flue gas increases,which will lead to fouling,erosion and plugging of downstream equipment. In this study,the main effects of SO_3 on the safety,stability and efficiency of units were analyzed,and measures to control SO_3 were proposed.

集成蓄热装置的火电机组调峰特性分析

【目的】随着新能源的大规模发展,新能源出力不确定性和波动性问题展现出来,而为了弥补新能源出力缺点,火电机组承担起了调峰作用。为了提升火电机组的调峰能力,对其调峰特性进行了研究。【方法】首先,以某350 MW供热机组作为分析对象,应用仿真软件搭建热力系统模型,并验证该模型的精确性。其次,以蓄热系统为辅助系统,研究机组在满足供热需求情况下的机组调峰能力,并分析蓄热等储能单元对机组调峰能力的影响。最后,采用启发式粒子群算法对蓄热水罐运行策略进行优化,得到随热负荷变化的储热罐最优运行模式。【结果】通过蓄热水罐与火电机组耦合的方法有效提升了机组的调峰和供热能力,并提出可以根据实际热负荷数据确定最大化收益的运行模式。【结论】该方法对机组的运行策略具有指导意义。

火电耦合压缩空气储能技术研究进展及展望

火电耦合压缩空气储能技术作为一种提升传统火电机组灵活性和经济性的有效手段,近年来受到了广泛关注。该文从分析火电耦合压缩空气储能技术在提升电网调峰能力、促进可再生能源整合等方面的重要意义出发。首先,介绍典型耦合系统的结构组成与工作原理;然后,探讨耦合系统中关键设备的技术现状和面临的挑战;之后,梳理火-储耦合系统的集成方案设计、调峰运行优化以及经济性评估的研究现状;最后,针对当前技术难点,展望未来火电耦合压缩空气储能技术的研究方向与重点。该文旨在为今后相关领域研究提供参考与借鉴,推动其持续发展和创新。

燃煤发电机组灵活调峰下机炉安全状态监测与调控研究综述

“双碳”背景下新能源大量接入电网,燃煤发电机组承担调峰任务,长期处于瞬态运行过程,其灵活运行水平需进一步提升,但深度调峰与快速变负荷使机组运行可靠性下降,机组灵活调峰能力面临设备安全性制约。该文对燃煤发电机组在灵活调峰下安全稳定运行的研究现状进行评述。首先,综述调峰工况下锅炉换热面、汽轮机转子等部件存在的安全技术问题,明确灵活运行对机组设备安全性的影响。其次,对比分析监测温度、应力等关键运行状态参数的不同方法优缺点与适用性;针对存在的安全技术问题介绍现有的机组运行参数优化与设备结构优化方法。未来将可靠性评估与诊断、停机保温预热及智能先进控制等技术应用于燃煤发电机组的调峰运行将对其安全性提升具有重要意义。最后,对目前燃煤发电机组灵活安全运行的研究现状及面临问题进行总结。

一种采用记忆神经网络和曲线形状修正的负荷预测方法

针对分布式电源和新型负荷容量累积造成负荷影响因素多元化和不确定性特性增强的问题,文中提出一种采用记忆神经网络和曲线形状修正的负荷预测方法。在负荷峰值预测中,采用最大信息系数计算负荷峰值与影响因素的非线性相关性,实现对输入特征的筛选;综合考虑负荷峰值序列的长短期自相关性和输入特征与负荷峰值的不同程度相关性,结合Attention机制和双向长短时记忆(bidirectional long short-term memory,BiLSTM)神经网络建立负荷峰值预测模型。在负荷标幺曲线预测中,通过误差倒数法组合相似日和相邻日,建立负荷标幺曲线预测模型;针对预测偏差的非平稳特征,利用自适应噪声的完全集成经验模态分解和BiLSTM网络建立误差预测模型,对曲线形状进行修正。应用中国北方某城市的区域电网负荷数据为算例,验证了所提模型的有效性。

涡旋膨胀机研究进展及展望

随着“双碳”目标的提出,涡旋膨胀机作为回收低品位能量的机械装置备受关注。首先,对近年来涡旋膨胀机的理论研究成果进行了综述,主要包括型线理论、热动力学和计算流体力学(CFD)仿真。然后,对涡旋膨胀机在有机朗肯循环(ORC)中的应用进行了总结,梳理了涡旋膨胀机在跨临界CO_(2)制冷循环中的应用研究成果。最后,对涡旋膨胀机未来的研究方向进行了展望。结果表明:变壁厚涡旋膨胀机因其可以在不增加泄漏线长度的情况下增加内容积比,因此将成为未来型线优化的主要方向;CFD仿真已成为重要的研究工具;润滑油是影响涡旋膨胀机性能的关键因素,提高润滑油的黏度有利于提升效率,而过量的润滑油则会使其性能下降;工作压力是影响涡旋膨胀机性能的最主要的因素,过膨胀、欠膨胀以及泄漏现象都会使其性能下降。此外,涡旋膨胀压缩一体机集成了膨胀机和压缩机两个功能单元于一个机壳中,显著简化了系统结构并提高了能量回收效率,是提升新能源车用CO_(2)热泵空调系统性能的有效途径。基于当前的研究成果和行业需求,提出涡旋膨胀机未来应继续深入研究和优化型线设计、减少泄漏、优化工作压力等,以满足日益增长的能量回收和环境保护需求。

考虑核电灵活参与调峰的多源联合运行低碳经济调度

在含高比例核电机组和新能源发电设备的沿海地区电网,系统调峰压力严峻。为了满足系统调峰需求,充分挖掘核电调峰潜力,建立核电灵活出力参与调峰的核-光-储-蓄-火联合运行优化调度模型。首先,针对核电灵活出力的非线性特性,采用0-1变量进行线性化有效约束;然后,充分考虑各电源的运行特性及成本,建立完整的系统运行约束;最后,在传统的以经济调度为优化目标的基础上,引入不同碳交易机制,并兼顾系统新能源消纳水平。算例分析验证了模型的有效性,结果表明,所提优化调度模型充分实现了核电的灵活出力,有效缓解了系统调峰压力,减少常规火电机组的频繁启停,并有效提高了新能源的消纳水平,使系统运行更加经济性和低碳性。

风-火-储耦合系统储能容量配置优化对比

为提升风电富集区域风电消纳水平及燃煤机组的灵活性,提出了基于热电共蓄式压缩空气储能的风-火-储耦合系统及系统调度策略,建立了系统的容量配置优化框架,并对7种布局方案进行了多目标优化。优化结果表明:电锅炉将弃风电量转化为热量时,燃煤机组的运行点向电力负荷下限更低的区域移动,风电上网空间增大,燃煤机组出力水平降低;加入热电共蓄式压缩空气储能子系统,使得燃煤机组电功率水平降低;换热器废热的回收进一步降低了燃煤机组产热水平;通过调整燃煤机组热出力,抽汽蓄热子系统能够实现抽汽热的时空平移,促使燃煤机组运行点向电力负荷下限更低的区域移动,可间接促进风电的消纳。综合来看,3种子系统相组合的最佳耦合方案可实现燃煤机组的热电解耦,从而提升了其深度调峰能力,在更大程度消纳风电能力的同时提升了系统的效率和环保性。

双碳目标下高温气冷堆替代中小型火电的思考

碳达峰碳中和是我国一项重要的国家战略决策,“双碳”目标的提出给能源行业带来了深刻的变革,我国能源结构将进一步优化,电力行业必须实现低碳转型,新能源取代火电已成为必然。本文分析了新形势下火电企业面临的巨大挑战、发电规模受到限制、经营成本不断上升,尤其是中小型火电机组,面临着淘汰和关停的局面,而高温气冷堆具有固有安全性、发电效率高、用途广泛的显著特点,使其替代中小型火电成为可能。本文通过厂址适应性、技术可行性、经济可行性三方面,分析了高温气冷堆替代中小型火电的可行性,并从相关法律法规适用性、内陆厂址所带来的问题、开展公众沟通等方面提出建议。

330 MW循环流化床锅炉深度调峰技术

为推进“双碳”政策的实施,消纳波动性较强的新能源并网发电,当前对火电机组的深度调峰要求越来越高。循环流化床(circulating fluidized bed,CFB)锅炉机组在深度调峰低负荷运行工况有着先天优势,但实现20%以下的超低负荷运行依然面临众多的困难,如炉内流化的稳定性、氮氧化物的排放及炉内局部超温带来的安全性等问题。以某330 MW CFB锅炉的深度调峰技术应用为例,介绍了输煤筛分破碎系统、风帽节流圈、下二次风管等机组部件的改造,并配合烟气再循环等技术应用,成功实现了18%的超低负荷深度调峰运行,同时也很好地控制了NOx的排放。最后总结了CFB机组超低负荷深度调峰技术的关键点和难点,对深度调峰运行带来的潜在问题进行了分析,并提出了相应的解决措施。研究结果具有重要的工程借鉴作用。

面向燃气机组调峰的天然气管网动态安全域

燃气机组调峰的灵活性有助于提升可再生能源消纳水平,但所造成的管道压力剧烈波动却为天然气管网引入新的安全风险。该文提出一种面向燃气机组调峰的天然气管网动态安全域,以表征满足动态管流安全的燃气机组有功调整量的集合。首先,分析以时域连续的气负荷质量流率作为注入空间的天然气管网动态安全域难以实用化的原因。为此,提出将燃气机组进气口质量流率转化为有功调整量的函数,定义以初始运行点为基准、以各燃气机组有功调整量为注入空间的天然气管网动态安全域。为兼顾计算精度和效率,基于时空正交配置法对管网连续变量进行近似离散,建立安全域边界搜索优化模型。并进一步揭示天然气管网稳态安全域可通过松弛该优化模型中部分约束条件求解得到,为动态安全域的一种退化形式。算例结果表明,所提方法克服天然气管网稳态安全域对于日内安全分析过于乐观的局限性,有助于增强电力-天然气耦合系统的协同态势感知能力。