Exergetic analysis and evaluation of coal-fired supercritical thermal power plant and natural gas-fired combined cycle power plant

The present work has been undertaken for energetic and exergetic analysis of coal-fired supercritical thermal power plant and natural gas-fired combined cycle power plant. Comparative analysis has been conducted for the two contestant technologies. The key drivers of energetic and exergetic efficiencies have been studied for each of the major sub-system of two contestant technologies. Overall energetic and exergetic efficiency of coal-fired supercritical thermal power plant are found to be 43.48 and 42.89 %, respectively. Overall energetic and exergetic efficiency of natural gas-fired combined cycle power plant are 54.47 and 53.93 %, respectively. The major energetic power loss has been found in the condenser for coal-fired supercritical thermal power plant. On the other hand, the major energetic power loss has been found in both the condenser and heat recovery steam generator for gas-fired combined cycle thermal power plant. The exergetic analysis shows that boiler field is the main source of exergetic power loss in coal-fired supercritical thermal power plant and combustion chamber in the gas-fired combined cycle thermal power plant. It is concluded that natural gas-fired combined cycle power plant is better from energetic and exergetic efficiency point of view. These results will be useful to all involved in the improvement of the design of the existing and future power plants.     

燃煤电站烟气污染物深度脱除技术的分析

近年来雾霾天气的频繁出现使得细颗粒物(PM2.5)成为了公众关注的热点,PM2.5的控制也已增加到2012年发布的《环境空气质量标准》中,而目前我国现有的烟气污染物控制技术难以脱除PM2.5,因此,为深度脱除PM2.5、SO2、SO3以及重金属等烟气污染物,开发燃煤电站烟气污染物深度脱除技术(深度脱除技术)成为亟待解决的问题。本文系统分析了开发适用于我国燃煤电站的深度脱除技术的必要性以及存在的问题,重点分析研究了PM2.5脱除技术、全负荷下超超临界锅炉的低NOx排放以及SCR工作温度的适应性。最后,以某电厂2×660 MW超临界机组为例,介绍了烟气污染物深度脱除系统方案,以此为基础,分析提出了1 000 MW超超临界机组烟气污染物深度脱除的技术路线。     

Retrofitting strategy for biomass co-fired power plant

Clean Technologies and Environmental Policy - The use of large-scale coal-fired units and biomass coupled power generation has significant advantages in achieving climate goals. Based on this, this...     

Update on air pollution control strategies for coal-fired power plants

Clean Technologies and Environmental Policy - Coal is expected to remain a significant power supply source worldwide and shifting to carbon-neutral fuels will be challenging because of growing...     

Thermal integration of different compression-train configurations for coal-fired power plant with carbon capture

Clean Technologies and Environmental Policy - Different compression-train configurations in a coal-fired power plant with CO2 capture were thermally integrated to reduce the energetic impact of the...     

A life cycle assessment of biomass cofiring in a coal-fired power plant

The generation of electricity, and the consumption of energy in general, often result in adverse effects on the environment. Coal-fired power plants generate over half of the electricity used in the U.S., and therefore play a significant role in any discussion of energy and the environment. By cofiring biomass, currently operating coal plants have an opportunity to reduce the impact they have, but to what degree, and with what trade-offs? A life cycle assessment has been conducted on a coal-fired power system that cofires wood residue. The assessment was conducted in a cradle-to-grave manner to cover all processes necessary for the operation of the power plant, including raw material extraction, feed preparation, transportation, and waste disposal and recycling. Cofiring was found to significantly reduce the environmental footprint of the average coal-fired power plant. At rates of 5% and 15% by heat input, cofiring reduces greenhouse gas emissions on a CO₂-equivalent basis by 5.4% and 18.2%, respectively. Emissions of SO₂, NO _x , non-methane hydrocarbons, particulates, and carbon monoxide are also reduced with cofiring. Additionally, total system energy consumption is lowered by 3.5% and 12.4% for the 5% and 15% cofiring cases, respectively. Finally, resource consumption and solid waste generation were found to be much less for systems that cofire. Electronic Publication     

Estimating the chronic health risk from coal-fired power plant toxic emissions

A general methodology for performing risk assessment is briefly discussed. This approach provides a framework within which the analyst can use specific environmental transport, exposure, and dose—response models that are appropriate to a particular problem. The framework has been implemented in a computer program that incorporates simplified environmental transport models with the models for calculating exposure rates and chronic health effects. The general framework and computer program are applied to illustrative case studies of coal-fired power plant emissions of arsenic and selenium. The problem of uncertainty in the results is discussed and several potential analysis approaches evaluated. A selected approach to uncertainty analysis is applied to the case studies. General conclusions about the risk assessment process and specific conclusions about the case studies are presented.     

PM_(2.5)测试方法对比及其燃煤电厂的排放特征分析

遵循电力行业标准DL/T 1520—2016,采用PM-10撞击器(30 L/min)、质量法撞击器(DGI,70 L/min)、静电低压撞击器(ELPI,10 L/min)对燃煤电厂的PM_(2.5)进行现场对比测试;并对燃煤电厂PM_(2.5)排放特征进行总结。结果表明,同一仪器不同时段的数据及不同仪器相同时间的数据重复性均较好。     

关于加快发展我国先进超超临界燃煤发电技术的战略思考

我国一次能源的结构特点决定了我国电力供应以燃煤发电为主的格局。为了推动燃煤发电的清洁、高效发展,电力工业大力开发并推广运用超超临界燃煤发电技术,优化了装机结构,推动了节能减排。实践证明发展先进燃煤发电技术是电力工业又好又快发展的重要保障。本文通过对我国超超临界燃煤发电技术研发的回顾,总结分析了该项目的成功经验。结合当前国情,并参考欧盟与美国先进超超临界技术的研究现状,提出了我国研发更高参数、更高效率的先进超超临界发电技术的发展思路和相关建议。     

Restoration strategy for secondary power network with grey relational analysis

An operational strategy for secondary power system restoration using grey relational analysis (GRA) is presented. The restoration scheme can be divided into three steps involving fault section determination, recovering process and voltage correction process. Three GRAs are incorporated to design the overall restoration scheme. The first GRA uses the network-switching status to identify the fault. The second GRA combines the switching states and load levels for network recovery. The third GRA uses capacitor bank control (CBC) to support bus voltages. Optimal power flow (OPF) is also used to verify the proposed scheme by off-line analysis to confirm a secure overall network operation including load-power balance, power generation limits, voltage limits and power flow limits. Computer simulations were conducted with an IEEE 30-bus power system to show the effectiveness of the proposed restoration scheme.     

Failure analysis of power plant boiler material

The failure of a boiler operating at 540°C and 9.4 MPa was investigated by evaluation of material removed from the near-failure region and by thermodynamic analysis. A scanning Auger microprobe, scanning electron microscope, and THERMO-CALC thermodynamic software (Thermo-Calc Software, Stockholm) were used in the investigation. Results showed that the segregation of impurity elements (phosphorous, tin, and nitrogen) to grain boundaries and the in-service formation of thin carbide films and granular carbides (Cr,Fe)₂₃C₆ on the grain boundaries were important factors in the failure process.     

车用复合电源模糊控制策略研究

将模糊控制策略应用于车用复合电源的管理中.基于超级电容和动力电池组的试验数据建立了其动态仿真模型,制定了复合电源的模糊控制策略和逻辑门限控制策略.依据选择的复合电源拓扑结构,选择城市测功机循环工况(UDDS),针对复合电源在整车上的应用进行了此两种控制策略的仿真对比分析.仿真结果表明,模糊控制策略可以更好地发挥超级电容...     

火电厂给水再循环管道振动分析与控制

针对某火电厂给水再循环管道振动的原因和集中位置进行分析并提出相应的控制方案。首先建立再循环管道和水流的实体模型、支吊架简化模型并进行装配,然后导入至ANSYS中进行CFX流体分析,得到水流作用于管道内壁的冲击压力并导入至结构力学模块进行二次分析,再将分析数据传递至模态分析模块进行运算,得到流固耦合作用下管系前50阶的固有频率和前6阶振型,最后结合实验测试结果分析再循环管道振动的原因和振型最大点位置分布规律,并提出相应的支吊架调整干预方案,调整后管系各阶固有频率有所上升,管系振动明显好转,表明所提控制方案可行、有效。该文工作对于火电厂给水再循环管道振动的监测和控制有参考价值。     

Characterization of fly ash from coal-fired power plants

X-ray analysis shows that mullite and silica are the major crystalline phases in fly ash. The method of known additions from X-ray diffraction techniques was used to calculate changes in the significant peak intensities of mullite and silica to determine their weight fractions in fly ash. This furthers the efforts of characterizing fly ash, which are being conducted to supplement the search for applications of this abundant material. The weight fractions of crystalline mullite and silica were determined to be 14.2 and 5.1 wt%, respectively. Thermal gravimetric studies as well as SEM and particle size analysis were also conducted on the fly ash.     

热电厂采用热电冷联供的适用性分析

利用等效发电效率概念,以300MW级抽凝式供热机组为例,对热电冷联供的适用性进行分析。在目前电、热价格以及发电机组装备水平的基础上,提出城市热电厂推广使用热电冷联供的约束性条件。     

并联混合动力汽车复合电源控制策略的研究

通过对复合电源在混合动力汽车(HEV)中应用的研究,设计了针对某款并联式混合动力汽车的复合电源结构,并对其效率特性进行了分析,提出了复合电源的功率分配控制策略以及电池给超级电容充电策略,基于MATALAB/Simulink,建立了复合能量存储系统模型,并嵌入ADVISOR软件中,在城市道路循环UDDS工况下进行了仿真研究。仿真结果表明,通过采用该复合电源控制策略,可以充分发挥超级电容和蓄电池各自的优点,改善整车储能系统的存储效率,提高制动能量的回收效率。     

Failure analysis of a run-of-the-river hydroelectric power plant

One of the challenges posed by hydraulic energy generation stems from the exploitation of hydrological resources that carry significant amounts of sediment that erodes the surfaces of turbines. This is the case for the Amaime hydroelectric plant, which is located in the western mountainous region of Colombia and was seriously affected by sediment after a brief period of operation. The main symptom indicating failure was a rise in the temperature of the bearings caused by an increase of almost two bars in the pressure between the cover on the side of the generator and the runner, which was caused by the wearing of the seal labyrinths. Inspections that were carried out after six months of operation indicated that there was a 300% increase in the clearance between the covers and the runner, which caused a higher axial thrust on the bearing. The inspections verified that severe wear had occurred on important elements of the turbine, such as the runner, guide vanes and turbine covers, which required major repairs to the two generation groups of the plant in less than 2 years, which is a much shorter time between repairs than is recommended by international standards. Analyses of the material, medium, particles and the worn surfaces demonstrated that the wear on the turbine was mainly due to erosion by hard particles, which was caused by the high sediment concentration and the low hardness of the material used to construct the turbine.     

某天然气热电联产项目噪声控制

天然气热电联产项目因其高效、环保、占地面积小、耗水少及建设周期短等优点而受到各国的广泛关注,但燃气电站噪声污染问题较为突出,通过声学照相机识别厂区内的噪声源,确定厂界的噪声值,对噪声源声学特性进行分析,建立噪声源及建筑的声学模型并进行仿真计算,确定噪声源对项目边界的影响并提出声学设计方案,对最终方案实施后的效果进行实测。结果表明该方案满足了声环境要求,可供同类大型燃气电厂的噪声控制项目参考。