Overlooked CO_(2)emissions induced by air pollution control devices in coal-fired power plants

China's efforts to mitigate air pollution from its large-scale coal-fired power plants(CFPPs)have involved the widespread use of air pollution control devices(APCDs).However,the operation of these devices relies on substantial electricity generated by CFPPs,resulting in indirect CO_(2) emissions.The extent of CO_(2)emissions caused by APCDs in China remains uncertain.Here,using a plant-level dataset,we quantified the CO_(2)emissions associated with electricity consumption by APCDs in China's CFPPs.Our findings reveal a significant rise in CO_(2)emissions attributed to APCDs,increasing from 1.48 Mt in 2000 to 51.7 Mt in 2020.Moreover,the contribution of APCDs to total CO_(2)emissions from coal-fired power generation escalated from 0.12%to 1.19%.Among the APCDs,desulfurization devices accounted for approximately 80%of the CO_(2)emissions,followed by dust removal and denitration devices.Scenario analysis indicates that the lifespan of CFPPs will profoundly impact future emissions,with Nei Mongol,Shanxi,and Shandong provinces projected to exhibit the highest emissions.Our study emphasizes the urgent need for a comprehensive assessment of environmental policies and provides valuable insights for the integrated management of air pollutants and carbon emissions in CFPPs.

Modeling the Dispersion and Atmospheric Mitigation of Pollutants in the Dibamba-Douala Thermal Power Plant

This work simulates the dispersion and atmospheric attenuation of pollutants from the Dibamba-Douala thermal power plant. The objective of this research is to study the dispersion of air pollutants and mitigate the impact of pollutants on the populations living around the power plant. The methodology used is as follows: the Gaussian model is used for the representation of the dispersion in the form of a plume, the finite difference method for digital resolution. Finally, dispersion charts are constructed which allow the heights of the chimneys to be fixed for which the concentrations of pollutants discharged comply with ambient air quality standards. The results obtained using the simulation made in the MATLAB software version 2016 show that, for a wind regime of 1.5 m/s;we have a predicted distance of 150 m at which the concentration is canceled out. Then, for the wind speed of 2 m/s;we had a predicted distance of 125 m and finally for a wind speed of 2.5 m/s;we observed the 120 m distance at which the concentration is canceled. In addition, for the same wind regimes, the attenuation of pollutants at ground level is obtained for a height of 60 m.

Discharge water temperature assessment of thermal power plantusing remote sensing techniques

Thermal power plants are generally constructed near to sea coast to meet their requirement of coolingwater. The warm water discharge from the thermal power plant is one of the major environmentalconcerns in view of the thermal pollution in the sea water. The temperature limit for the warm waterdischarge from the thermal power plant has to be monitored and controlled. Coastal Gujarat PowerLimited (CGPL) operates (24×7) at an “once-through system” based sea water circulation for powergeneration. The used sea water is then discharged into the sea through an outlet channel. As per environmental norms, the discharge water temperature needs to be maintained below the stipulated “delta”rise (+7 ℃) with respect to ambient sea surface temperature at the inlet. We demonstrate the applicability of thermal remote sensing data in understanding the seasonal and temporal variations of thetemperature difference between the discharge water and the ambient sea water. We used thermal banddata from Landsat-8 satellite imagery to map water surface temperature and create temperature profilesalong the intake and outflow channels (till the sea), to understand the variation of temperature andestimate the “DT” between intake point and various observation points along the outflow. This analysiswas carried out for all 11 months (except June) of the year 2018 to correlate temperature variations withseasonal changes. Tidal conditions during the time of data acquisition were also considered to accountfor the effect of tides on DT. The result shows that the average temperature rise between intake andoutflow are maintained at ~3 ℃ across all the months of 2018, with minor variations in the months ofJuly and August. Further, average temperature drop from outflow to cooling channel (before diaphragm)is seen to be ~2 ℃ across all the months with similar seasonal fluctuations.

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.

The Experimental Investigation of Recirculation of Air-Cooled System for a Large Power Plant

The paper introduces thermal buoyancy effects to experimental investigation of wind tunnel simulation on direct air-cooled condenser for a large power plant. In order to get thermal flow field of air-cooled tower, PIV experiments are carried out and recirculation ratio of each condition is calculated. Results show that the thermal flow field of the cooling tower has great influence on the recirculation under the cooling tower. Ameliorating the thermal flow field of the cooling tower can reduce the recirculation under the cooling tower and improve the efficiency of air-cooled condenser also.

An integrated analysis of air pollution from US coal-fired power plants

The United States is one of the world’s leaders in electricity production,generating about 4116 billion kWh in 2021,of which coal accounted for 21.8%of the total.This study applies an integrated approach using both terrestrial and satellite data to specifically examine emissions from coal-fired power plants and its spatial extent.The study also highlights the effectiveness of government policies to reduce emissions.It was found that emission of pollutants from the country’s energy sector has been steadily declining,with annual emissions of sulfur dioxide(SO_(2))and nitrogen oxides(NOx)decreasing from the US electric power sector between 1990 and 2020 by 93.4%and 84.8%,respectively,and carbon dioxide(CO_(2))by 37%between 2007 and 2020.Although overall emissions from coal-fired power plants are declining,some individual plants have yet to install environmental equipment to control emissions.According to US government data,major emitters of SO_(2),NO_(x),and CO_(2) in the US are the Martin Lake power plant in East Texas,the Labadie power plant near St.Louis,Missouri,and the James H Miller Jr plant near Birmingham,Alabama.This study also integrates TROPOMI satellite data to detect point emissions from individual power plants.While the highest levels of measured pollutants were over the country’s major cities and areas of fossil fuel extraction,TROPOMI could clearly distinguish the pollution caused by power plants in more rural areas.Although the US has made great strides in reducing emissions from coal-fired power plants,these plants still represent a major source of pollution and remain a major concern.Totally eliminating coal as a power source will be difficult with the higher power demands resulting from the transition to electric automobiles.

Increasing Coal-Fired Power Plant Operational Flexibility by Integrating Solar Thermal Energy and Compressed Air Energy Storage System

This paper proposed a novel integrated system with solar energy,thermal energy storage(TES),coal-fired power plant(CFPP),and compressed air energy storage(CAES)system to improve the operational flexibility of the CFPP.A portion of the solar energy is adopted for preheating the boiler’s feedwater,and another portion is stored in the TES for the CAES discharging process.Condensate water from the CFPP condenser is used for cooling compressed air during the CAES charging process.The thermodynamic performance of the integrated system under different load conditions is studied.The system operations in a typical day are simulated with EBSILON software.The system enables daily coal saving of 9.88 t and reduces CO_(2)emission by 27.95 t compared with the original CFPP at 100%load.Under partial load conditions,the system enables maximum coal saving of 10.29 t and maximum CO_(2)emission reduction of 29.11 t at 75%load.The system has maximum peak shaving depth of 9.42%under 40%load condition.The potential of the system participating ancillary service is also discussed.It is found that the integration of solar thermal system and CAES system can bring significant ancillary service revenue to a conventional CFPP.

广西某火电厂建设对区域碳排放影响初析

随着“3060双碳”目标的提出,为研究火电厂建设对区域碳排放的影响,笔者以广西某火电厂为例,根据燃煤发电行业碳排放量核算方法,计算得出该火电厂碳排放总量;分析碳排放对区域降碳的影响,并提出减污降碳措施。结果表明,该火电厂建设会大大增加区域碳排放总量,不利于实现区域降碳目标。所提出的降碳措施可为降低区域碳排放提供依据。

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。

火力发电厂锅炉空气预热器安装控制技术研究

为了提升火力发电厂锅炉空气预热器的安装质量,本文深入分析了影响安装质量的多种因素,包括设备设计、材料选择、施工环境等。通过详细分解空气预热器的安装步骤,提出了针对性的控制策略,并设计了科学的安装技术方案。在现场质量验收评定环节,本文强调了对安装成果的全面评估,确保空气预热器的高效、安全运行。研究结果表明,通过严格控制安装过程,优化安装技术,能够显著提升火力发电厂锅炉空气预热器的安装质量,为电厂的稳定运行提供有力保障。

火电厂回转式空气预热器优化改造分析

回转式空气预热器是大中型电站锅炉中广泛采用的尾部换热设备,当前国内300 MW及以上燃煤机组锅炉普遍适用,但由于风侧、烟侧及炉外空气压力不同,空气预热器必然存在漏风隐患,影响机组运行的经济效益。为了提高锅炉热效率,很多电厂采取了各种改造或调整措施,虽然空气预热器漏风依旧不可避免,但是在一定程度上降低了漏风率。针对超临界锅炉普遍使用的三分仓回转式空气预热器,为了降低其漏风率,减少锅炉排烟热损失,提高机组经济效益,通过技术分析找到漏风的原因,并提出针对性的方案措施,提高设备应用的可靠性,有效降低火电厂的能耗水平。

基于支持向量机的火力发电碳排放量智能检测方法研究

为准确得到碳排放量,研究基于支持向量机的火力发电厂碳排放量智能检测方法。确立火力发电厂碳排放核算系统边界,建立碳排放系统,分别计算燃煤发电产生的碳排放量、脱硫环节直接产生的碳排放量以及五类间接产生碳排放量的环节整体生成的碳排放量。基于支持向量机设计碳排放量检测算法,得到原始数据的归一化指标,得到支持向量机算法下的最终规划结果。实验结果显示,该检测方法可有效得到不同季节下的碳排放量,精度较高,具备较好的实用价值。

火力发电厂回转式空气预热器性能改造研究

文章系统分析预热器运行现状,针对换热效率低、漏风量大等关键问题,提出创新的综合改造方案。该方案包括应用新型密封技术、优化换热元件以及使用高频声波吹灰装置等措施。通过对某电厂机组预热器的实验改造,评估方案的实际效果。实验结果表明,改造后预热器的热效率显著提高,漏风率大幅降低,换热端温差明显减小,比热耗和热损失均得到改善,说明所提出的改造方案可以显著提升回转式空气预热器的性能。

直接空冷火电机组乏汽余热利用技术

火电厂汽轮机排汽(乏汽)需要冷凝成液态水用于系统循环,湿冷、干冷机组都需要消耗大量能量来冷凝乏汽。北方缺水地区采用直接空冷火电机组,大量乏汽通过空冷岛散热。从热力学第二定律来看,乏汽已无做功能力,但是汽化潜热与做功能力无关,在能够提供真空环境确保乏汽流动性和需要加热远低于乏汽温度的工质的情况下,乏汽中的汽化潜热仍具有很高的回收价值。尤其对于直接空冷火电机组,其汽轮机排汽压力和温度均高于湿冷机组,可以采用汽水换热器直接回收乏汽热量加热厂区生水,降低电厂辅助蒸汽的消耗量,提高电厂收益。

Consideration of Environmental Effect of Power Generation: Bangladesh Perspective

Nowadays for power generation, environment is a major consideration. The heart of power generation is power station. At present there are almost above 40(Both Government & Rental) power station in Bangladesh. Among these 80% of power station is gas based. Rest of the 20% is coal, liquid and furnace oil based. Bangladesh has only one Hydraulic power station. These gas and coal based power stations are giving adverse effect in Bangladesh. The main emissions from coal combustion at thermal power plants are carbon dioxide (CO), nitrogen oxides (NO), sulfur oxides (SO), chlorofluorocarbons (CFCs), and air- borne inorganic particles such as fly ash, soot, and other trace gas species. Carbon dioxide, methane, and chlorofluorocarbons are greenhouse gases. These emissions are considered to be responsible for heating up the atmosphere, producing a harmful global environment. It is known to all that hydro power station is a clean source of energy, but it has also some ecological and environmental effect. Dhaka is one of the top polluted city in the world. So for power generation if the environmental effect is not considered then Bangladesh will be in great trouble. The purpose of this paper is to discuss the present and future possible environmental effect of power generation in Bangladesh.

The Impact of Traffic Emission on Air Quality in an Urban Environment

Study of the impact of traffic emissions on air quality around the Haram Mosque in Makkah, Saudi Arabia, was conducted experimentally, numerically and statistically. Experimental study was performed to measure existing air quality. Numerical study was done to model the extent of air movement and pollutant dispersion within and around the Haram area. Statistical study was conducted to determine correlation coefficients, auto-correlation and time lags of each pollutant. Pollutant measurements were carried out using an air quality mobile laboratory at three sites. Numerical calculations were made using an ISC-AERMOD dispersion model. Concentrations of traffic emissions including nitrogen dioxide (NO2), sulfur dioxide (SO2), carbon monoxide (CO), ozone (O3) and airborne particulate material under 10 μm diameter (PM10) are presented and analyzed. The calculated concentrations are validated by comparing with observed values at the three sites. The results indicate good agreement between calculated concentrations and observed values, which demonstrate satisfactory model performance. Results show that the Haram area is experiencing high concentrations of dust. High buildings around the Haram Mosque act as flow obstacles. Mean pollutant dispersion was toward the south and southeast during January and June. Highest mean concentrations were observed in January and June.

中国燃煤电厂大气污染物治理历程及展望

中国燃煤电厂超低排放的改造工作已基本全面完成,环境空气质量也明显改善。为弄清燃煤电厂未来是否还需加严大气污染物排放标准及持续开发新的烟气治理技术,在系统梳理中国燃煤电厂发展及大气污染物治理历程的基础上,结合火电行业大气污染物排放占比仍然较高,环境空气持续改善需求迫切的实际情况,提出了燃煤电厂大气污染物排放标准与烟气治理技术展望。(1)中国电力工业始于1882年,经历了蹒跚起步、艰苦创业、蓬勃发展和创造辉煌4个阶段。与新中国建国初期相比,2022年全国装机容量和发电量分别增长了1383倍和1950倍,2013年以来中国发电装机容量和发电量一直居于世界首位,2022年已超过G7国家的总和。一百多年来,中国发电装机和发电量中一直以火电为主(基本上都是煤电),单机容量逐渐扩大,2021年已建成世界上单机容量最大供电煤耗最低的135万kW燃煤发电机组。火电装机容量持续增长,但占比已从2006年的83.3%下降至2022年的53.0%。(2)1991年以前中国燃煤电厂烟尘、SO_(2)和NO_(x)均无排放浓度标准,之后的30多年来燃煤电厂大气污染物排放标准经历了3次修订,从世界最宽松的排放标准限值到世界最严的排放标准限值,催生了中国燃煤电厂的超低排放。与此同时,烟尘、SO_(2)和NO_(x)治理技术不断取得新突破,引领世界。2007年国家开始实施脱硫电价政策,2011年开始实施脱硝电价政策,2014年增加了除尘电价,2016年出台了超低排放电价政策,为保障烟气治理设施的高效运行发挥了重要作用。在国家环境保护行政主管部门的组织下,逐步构建了涵盖燃煤电厂“排放标准-技术指南-工程规范-验收检测-运行管理”全流程的烟气治理技术标准体系,实现了烟气治理“设计好、建设好、运行好、效益好”的有机统一。相比2006年火电行业烟尘、SO_(2)的排放峰值,2022年烟尘、SO_(2)排放量分别下降了97.3%和96.4%;相比2011年火电行业NO_(x)的排放峰值,2022年NO_(x)排放量下降了93.1%。(3)中国环境空气质量标准PM_(2.5)年均浓度35μg/m^(3)是世界卫生组织指导值的7倍,是美国1997年标准值的2.3倍,目前中国环境空气中PM_(2.5)年均浓度的实际水平是美国的4倍多,是俄罗斯、巴西等国的3倍多,衔接美丽中国健康中国的目标,中国环境空气中PM_(2.5)年均浓度至少需下降50%。2020年火电行业排放的SO_(2)、NO_(x)分别占工业污染源排放总量的30.8%和20.9%。借鉴发达国家环境空气改善的经验和中国电煤消费量持续增长的实际情况,火电行业大气污染物排放量至少需要下降70%以上,这就需要突破尘、硫、硝一体化的烟气高效治理技术和传统烟气治理技术低成本低能耗的提效改造技术,实现燃煤电厂的超净排放。

“上大压小”降低中国煤电的大气污染排放——基于供应链视角

通过构建点源精度的煤炭运输网络模型,编制高空间分辨率的煤电供应链大气污染物(氮氧化物(NO_(x))、二氧化硫(SO_(2))、颗粒物(PM)和大气汞(Hg))排放清单,从供应链视角全面评估该政策在2011~2018年间对中国煤电供应链的污染减排效应.结果表明,尽管我国燃煤发电总量增长了38.6%,但煤电供应链NO_(x)、SO_(2)和Hg排放总量分别仅增加了10.4%、16.2%和6.8%,PM排放总量甚至减少了15.8%.相较于退役电厂,新建电厂NO_(x)、SO_(2)、PM和Hg的供应链排放强度分别下降了63.2%、62.1%、90.2%和67.8%.从供应链的各环节来看,燃煤发电阶段的排放强度降幅最大;开采单位煤炭产生的排放基本不变;运输单位煤炭产生的排放小幅下降.本研究还从优化厂址布局、加强矿山管理和提升末端治理技术等方面提出了减排政策建议,也为其他高污染行业的减排路径探索提供重要参考.

燃煤火力发电厂大气污染治理技术探究

分析了燃煤火力发电厂大气污染问题,总结了大气污染的治理技术要点,结合当前环境污染问题加重的形势,以保护空气环境为目的,治理大气污染的现象,对燃煤火力发电厂造成的大气污染进行规避,以推动燃煤火力发电厂的稳定、绿色化、环保化运转。

火电厂大气污染物排放控制技术分析

在火电厂的运行过程中,大气污染物排放控制是一项关键内容。为实现此项技术的良好应用,以某火电厂的实际项目为例,对其中的脱硫技术、脱硝技术、除尘技术改进与应用进行了分析。希望通过本次的分析,能够为火电厂大气污染物排放的有效控制提供科学参考。