Study on Coal Consumption Curve Fitting of the Thermal Power Based on Genetic Algorithm

Coal consumption curve of the thermal power plant can reflect the function relationship between the coal consumption of unit and load, which plays a key role for research on unit economic operation and load optimal dispatch. Now get coal consumption curve is generally obtained by least square method, but which are static curve and these curves remain unchanged for a long time, and make them are incompatible with the actual operation situation of the unit. Furthermore, coal consumption has the characteristics of typical nonlinear and time varying, sometimes the least square method does not work for nonlinear complex problems. For these problems, a method of coal consumption curve fitting of the thermal power plant units based on genetic algorithm is proposed. The residual analysis method is used for data detection;quadratic function is employed to the objective function;appropriate parameters such as initial population size, crossover rate and mutation rate are set;the unit’s actual coal consumption curves are fitted, and comparing the proposed method with least squares method, the results indicate that fitting effect of the former is better than the latter, and further indicate that the proposed method to do curve fitting can best approximate known data in a certain significance, and they can real-timely reflect the interdependence between power output and coal consumption.

Development of Sensible Heat Storage Materials Using Sand, Clay and Coal Bottom Ash

In this paper, the mechanical and thermal properties of a sand-clay ceramic with additives coal bottom ash (CBA) waste from incinerator coal power plant are investigated to develop an alternative material for thermal energy storage (TES). Ceramic balls are developed at 1000°C and 1060°C using sintering or firing method. The obtained ceramics were compressed with a compression machine and thermally analyse using Decagon devise KD2 Pro thermal analyser. A muffle furnace was also used for thermal cycling at 610°C. It was found that the CBA increased the porosity, which resulted in the increase of the axial tensile strength reaching 3.5 MPa for sand-clay and ash ceramic. The ceramic balls with the required tensile strength for TES were selected. Their volumetric heat capacity, and thermal conductivity range respectively from 2.4075 MJ·m-3·°C-1 to 3.426 MJ·m-3·°C-1 and their thermal conductivity from 0.331 Wm-1·K-1, to 1.014 Wm-1·K-1 depending on sand origin, size and firing temperature. The selected formulas have good thermal stability because the most fragile specimens after 60 thermal cycles did not present any cracks. These properties allow envisioning the use of the ceramic balls developed as filler material for thermocline thermal energy storage (structured beds) in Concentrating Solar Power plants. And for other applications like solar cooker and solar dryer.

Mercury emissions and partitioning from Indian coal-fired power plants

In India coal combustion is the single largest source of emission of mercury which is a widespread persistent global toxicant,travelling across international borders through air and water.As a party to the Minamata convention,India aims to monitor and reduce Hg emissions and stricter norms are introduced for mercury emissions from power plants(30μg/Nm 3 for flue gas in stack).This paper presents the results obtained during the experimental studies performed on mercury emissions at four coal-fired and one lignite-fired power plants in India.The mercury concentration in the feed coal varied between 0.12-0.27 mg/Kg.In the mercury mass balance,significant proportion of feed coal mercury has been found to be associated with fly ash,whereas bottom ash contained very low mercury.80%-90%of mercury was released to air through stack gas.However,for circulating fluidised bed boiler burning lignite,about 64.8%of feed mercury was found to get captured in the fly ash and only 32.4%was released to air.The mercury emission factor was found to lie in the range of 4.7-15.7 mg/GJ.

Research on solar aided coal-fired power generation system and performance analysis

Integrating solar power utilization systems with coal-fired power units, the solar aided coal-fired power generation (SACPG) shows a significant prospect for the large-scale utilization of solar energy and energy saving of thermal power units. The methods and mechanism of system integration were studied. The parabolic trough solar collectors were used to collect solar energy and the integration scheme of SACPG system was determined considering the matching of working fluid flows and energy flows. The thermodynamic characteristics of solar thermal power generation and their effects on the performance of thermal power units were studied, and based on this the integration and optimization model of system structure and parameters were built up. The integration rules and coupling mecha- nism of SACPG systems were summarized in accordance with simulation results. The economic analysis of this SACPG system showed that the solar LEC of a typical SACPG system, considering CO2 avoidance, is 0.098 $/kW·h, lower than that of SEGS, 0.14 $/kW·h.

Atmospheric Dispersion Modeling of the Emissions from the Logbaba Thermal Power Plant, Douala-Cameroon

Air quality in the vicinity of the thermal power plant of Logbaba in the town of Douala was investigated in this study using data collected in a 5-year period (2008-2012). The distribution of pollutants such as SO2, NOx, CO and the particle matter PM2.5 was analyzed using numerical modeling, based on physical and thermal characteristics, as well as the operating periods of the power plant. The American Environmental Regulator Model (AERMOD) that is an atmospheric dispersion model was used for simulation. The wind rose and others National Oceanic Atmospheric Administration (NOAA) in-situ data were used for the validation of the model. The pollutants distribution was evaluated at two locations: the exit of the power plant, considered as reference point, and at 330 m away from the exit where the first houses appeared. The results show that the relative concentration for each contaminant at the exit of the power plant is 7.2% for the PM2.5 during 24 hours of emission, 46.0% for CO over 8 hours of emission, and 17.5% for SO2 over one hour. The NOx is the highest pollutant with 259.1% over an hour of emission and 51.0% over one year. Beyond 330 m of the power plant, only NOx keeps a polluting character with a relative rate of 100%. These results show that the pollution level of the power plant is over the threshold for air quality set by the World Health Organization. Moreover, among all pollutants investigated, NOx appears to be the most critical for the population in the vicinity of the Logbaba thermal power plant. This information is therefore important for policy and decision makers in preventing the vulnerability of the population to air pollutants from such industrial settings.

煤电机组耦合储热系统的灵活性调峰特性研究及其性能评价

“双碳目标”背景下,煤电机组将长期作为主力调峰电源,保障电网安全稳定。储热是提升煤电机组灵活性的重要手段,但煤电耦合储热系统的运行特性尚不明确,不同储热技术与煤电机组耦合适应性亟待研究。为此,该文构建600 MW煤电-90 MW显热/潜热/热化学储热3种耦合系统,详细考察系统储/释热过程调峰能力及热力学性能,并基于优劣解距离法(technique for order preference by similarity to an ideal solution,TOPSIS)综合评价,明确最优耦合方案。研究发现,储热过程,Ca(OH)_(2)/CaO热化学储热的调峰容量、调峰深度及?效率均优于热水及熔融盐储热,而释热过程熔融盐储热性能最优;通过TOPSIS综合评价法确定热储热方案均为抽取主蒸汽作为热源,最佳释热方案均为以#2高加进水为冷源,同时确定煤电耦合熔融盐储热为最佳系统耦合方案。相关研究结论可为构建煤电耦合储热调峰系统提供一定的理论和数据支撑。

300 MW超临界二氧化碳燃煤发电机组热经济性分析

针对300 MW超临界二氧化碳(SCO_(2))部分冷却循环和部分冷却再热循环燃煤发电系统,建立了热经济性数学模型,以循环热效率η_(t)、系统㶲效率η_(ex)及平准化度电成本C_(LCOE)为评价指标,对不同系统和不同关键参数进行热经济性对比分析。结果表明:在设计工况下,与部分冷却循环系统相比,在部分冷却再热循环下η_(t)高0.33%,η_(ex)高0.35%;在相同参数条件下,2个发电机组燃煤消耗成本占比均超过70%,锅炉成本远高于其他设备成本;存在最优的主压缩机入口压力,使得η_(t)、η_(ex)达到最大,同时C_(LCOE)达到最小;随着主压缩机入口温度的增大,η_(t)、η_(ex)逐渐减小,C_(LCOE)则逐渐增大;η_(t)、η_(ex)随着透平入口温度的增大线性提升,C_(LCOE)则先减小后增大。

高水分褐煤流动性离散元数值模拟

【目的】由于火电厂实际运行下使用的均为高水分褐煤,输送煤的过程中经常会发生堵塞以及黏附等问题。因此,利用EDEM软件对该问题进行数值模拟分析。【方法】通过对现场煤样考察分析,模拟过程中主要对煤的粒径、水分以及流动总量进行分析,并探究其对煤的流动性的影响。数值模拟分析后,将流动速度以及颗粒之间作用力进行对比,得到各项因素对煤流动的影响。【结果】造成堵塞的主要原因如下:首先,煤的粒径过大或过小导致在仓体流动过程中其自身颗粒与颗粒之间发生相对作用;其次,煤在仓体流动过程中,随着煤量增加,其流动状态由整体流动转变为中心流动;最后,煤的含水率是最主要的因素,其不仅影响自身黏附性,还会引起自重的增加,所以水分过大会引起流动缓慢,进而发生堵塞。【结论】研究结果可为解决燃煤电厂堵煤问题提供理论支持。

基于聚类算法的动力用煤资源质量评价方法与应用研究

为了快速、准确评价淮南煤田动力用煤资源的等级,达到合理开发利用优质动力用煤资源的目的,基于淮南煤田钻孔煤质大数据库,选取8煤层作为研究对象,将煤的发热量、灰分、硫分、挥发分、软化温度和哈氏可磨性作为动力用煤资源质量评价的基础指标。基于GIS平台,利用ISODATA算法对研究区动力用煤资源进行聚类,深入挖掘煤质数据信息。结合熵权法确定出每一簇类评价指标的权重,通过综合指数法实现动力用煤资源优劣等级的划分。研究结果表明,淮南煤田8煤层动力用煤资源聚类可分为三类,第二簇类动力用煤资源质量最好,其次为第三簇类,第一簇类质量相对较差。其中,第二簇类中优质煤占比最多,第三簇类以中质煤为主,第一簇类则以中质煤、低质煤为主。这为今后淮南煤田动力用煤资源合理开发利用提供了技术指导,并拓展了煤田煤质数据库的利用方式。

基于再热蒸汽抽汽-熔盐储热的火电系统分析

提出了一种基于再热蒸汽-抽汽熔盐储热的火电联合系统,通过建立仿真模型对系统的运行过程及效率进行了分析。为了使熔盐放热过程匹配主蒸汽温度,需要在抽汽充热过程之后再配置电加热器对熔盐提温,在此基础上研究了充热过程平均换热温差、放热过程夹点温差、低温储热温度对系统性能参数的影响。结果表明:充热过程中维持10 K平均换热温差,放热夹点温差从5 K增加至15 K会导致最高等效往返效率从88.2%降低至85.0%,同时最佳储热温度从314℃升高至324℃;放热过程中维持10 K夹点温差,充热过程的平均换热温差从5 K增加至15 K时,最高等效往返效率从89.5%降低至85.8%;2个温差均在10 K时,机组的最高等效往返效率为87.1%,该条件下运行时机组最低负荷可从30%下调至24.3%。

基于LSTM的煤场热值损失多因素线性回归预测

针对火力发电厂煤场热值损失问题,提出了一种基于长短期记忆(LSTM)的多因素线性回归综合热值损失预测模型。使用LSTM神经网络预测煤场所在地的环境因素,建立煤堆热值变化与时间累积下各因素总值之间的回归方程,代入预测因素的影响值以计算未来的热值损失。在煤场进行实地数据采样,对高位热值进行同值灰分处理,利用所记录的环境因素数据对因变量热值进行多因素回归分析,建立热值损失数学模型。通过构建LSTM神经网络预测多因素变化,将预测数据导入回归模型进行热值变化的预测。仿真结果表明:多因素LSTM神经网络对环境因素的预测精度要高于单因素及传统差分自回归移动平均(ARIMA)模型,并且具有较强的稳定性。

燃煤电厂袋式除尘器环保与节能耦合的性能优化研究

燃煤电厂袋式除尘系统在进行超低排放的过程中会消耗大量能源,为了使除尘器在满足出口烟气浓度排放指标的情况下以最优能耗的状态运行,收集燃煤电厂运行期间的监测数据,通过对除尘系统中涉及到能量的消耗及组成进行分析,建立单位质量除尘能耗指标模型和除尘效率指标,并研究灰分、燃煤热值和发电机组负荷率对除尘系统的影响规律。结果表明:除尘效率随灰分增加而提高,单位质量除尘能耗随灰分增加而减少并在灰分为18%时获得最佳能耗,燃煤热值的增加会使单位质量除尘能耗整体上升,但除尘系统在高热值区间运行较为稳定,机组负荷率在中高区间时,单位质量除尘能耗几乎没有变化,但设备能耗随负荷率的增加而线性增大,当机组超负荷时,最佳单位质量除尘能耗值会大幅上升,使得系统工作效益较低。

基于模糊综合评价法的热电厂设备安全风险评估

为定量评价热电厂生产过程中的安全隐患,对热电厂的储煤运煤、锅炉设备、除灰除渣和脱硫脱硝四个子系统中存在的主要危险源进行辨识,并采用模糊综合评价模型进行评估。通过层次分析法确定了热电厂一级主因素和二级子因素的权重并对各因素的危险性大小进行排序;通过计算隶属矩阵得出一级模糊评价矩阵和二级模糊评价矩阵,得出基于专家打分的四个子系统的危险性水平和热电厂的危险性水平,最后计算出该热电厂的安全评价分值为92.7分。所得结论对提高该热电厂的安全水平和后续安全管理具有理论指导作用。

风冷式干除渣系统在1×330 MW机组中的应用与优化改造

东海热电330 MW机组采用传统的水力除渣方式,存在水资源浪费、能耗高、安全性差、维护费用高等问题。对电厂生产过程中炉渣的排放方式及提高炉渣的综合率方面进行研究论证,将水力除渣系统改造成风冷式干除渣系统,改造后简化了排渣系统,提高了能源利用率及锅炉的效率。风冷式干除渣系统灰渣燃烧充分、含碳量低,保留了炉渣的活性,利于灰渣综合的利用,提高了社会效益及经济效益,对提高整个电厂的经济运行水平具有非常重要的意义。

减少火力发电厂煤质化验误差的策略分析

煤质化验工作是煤炭资源开发的重要环节,与煤炭的价格和经济效益有着直接关联,并重点探讨如何减少火力发电厂煤质化验的误差,详细总结了减少误差的重要性,并对采样与制样、系统与收缩、样品分析等影响因素展开分析,提出了规范操作行为、加大培训力度、完善管理机制、做好记录工作等控制措施,以期为煤质化验的质量优化提供有效参考。

燃煤电厂减污降碳协同增效综合评价体系构建及实证研究

燃煤电厂是我国大气污染物和温室气体排放的重要来源,在减污降碳协同推进的新目标形势下,如何实现减污降碳协同增效是燃煤电厂实现高质量发展的关键。开展燃煤电厂减污降碳协同增效评价研究有助于识别燃煤电厂减污降碳协同增效的现状及潜力,为燃煤电厂提升减污降碳协同增效水平提供路径分析支撑。本文在解析燃煤电厂实现减污降碳协同增效内涵的基础上,提出了定性与定量相结合的燃煤电厂减污降碳协同增效综合评价体系,涉及发展水平提升、能源低碳转型、资源循环利用、污染高效治理、助力社会减排、管理能力提升等六方面共计23项二级指标。以某沿海燃煤电厂为例,评估其2018年、2020年及2022年的减污降碳协同增效综合指数(ICSP)。结果表明,案例电厂2022年相较2018年ICSP从不足50分提至80分以上,改善幅度超70%,实现了主要大气污染物与二氧化碳的协同减排,但在能源低碳转型、污染高效治理、助力社会减排等方面仍有较大提升空间,尤其是脱硫脱硝设施能耗进一步优化空间较大。研究显示,本文建立的减污降碳协同增效综合评价体系具有一定实用性,可充分反映燃煤电厂的减污降碳潜力及工作成效。

基于火电机组运行数据判断煤质变化及其影响的方法

“双碳目标”下,火电厂的职能由供电主力方逐渐转变为调节配合方,其出力范围则是调节能力的重点指标。煤热值对火电机组的出力范围有着重要的影响。过去的煤质检测主要依赖于煤质报告分析,但这种方法在实时性和便捷性上有所欠缺。为解决这个问题,我们提出了一种基于火电机组运行数据监测煤质变化的方法,并以实际煤质报告的低位发热量对所提方法进行验证。最后,我们计算了煤质变化对机组出力范围的影响。

基于AHP-CRITIC博弈论组合赋权的配煤掺烧效果综合评估研究

为了提高配煤掺烧效果的评价准确性和合理性,建立了一个涵盖安全性、经济性和环保性3个维度及13个评价指标的综合评价体系。首先,采用层次分析法(AHP)和CRITIC赋权法获取各指标的主客观权重;然后,应用博弈论组合赋权法优化权重分配,得出组合权重,并结合模糊综合评价法,得出各配煤方案的评价等级与评分;最后,通过障碍度分析,识别影响配煤掺烧效果的主要指标。研究结果表明,环保性指标与安全性指标是影响配煤掺烧效果的重要因素,通过优化这些指标可以提升燃煤机组的运行水平。所提出的评价模型可为电厂管理者提供决策支持,促进燃煤电厂朝着低碳化、绿色化方向发展。

火电厂运行调整及锅炉燃烧调整对飞灰品质的影响分析

锅炉是火电厂运行中的重要设备,主要利用煤粉燃烧产生的热量进行汽轮发电。但是,锅炉燃烧期间会产生大量飞灰,如果飞灰中的含碳量超出了要求标准,则会影响飞灰品质,还容易对周围环境造成污染。火电厂运行调整和锅炉燃烧调整都会对飞灰品质产生不同程度的影响,要清楚各类要素的影响程度,并从提高飞灰品质和降低飞灰中含碳量的角度出发,做好火电厂运行调整、锅炉燃烧调整以及优化煤种质量和配置等工作,完善调整控制措施,切实提升锅炉燃烧中飞灰的质量。

浅谈气膜煤场在广东某大型海边火力发电厂上的应用

[目的]随着环保政策的日趋严格,国内大型燃煤电厂普遍采用封闭型煤场以避免煤尘外逸污染环境。近年来气膜作为一种新型封闭环保建筑形式,在储煤场的应用上开始逐渐增多。[方法]结合广东某大型海边火力发电厂首次在华南地区应用大跨度气膜煤场的案例,从气膜煤场方案比选、选型设计、布置等方面做出论证分析,[结果]与传统钢结构煤场相比,气膜在大跨度煤场中的应用优势明显。[结论]促进气膜煤场在大型火力发电厂上的推广应用。