生态文明建设是一场涉及生产方式、生活方式、思维方式和价值观念的革命.总结了清洁煤电"近零排放"的提出背景、环保政策及排放标准的发展历程,分析了燃煤大气污染物烟尘、二氧化硫(SO2)、氮氧化物(NOx)和汞等重金属排放控制技术发展现状以及燃煤机组实现"近零排放"的技术路线.选取不同区域典型燃煤机组进行案例分析,结果表明:典型机组烟尘、SO2及NOx排放浓度长期低于5、35、50 mg/m3,锦界三期、寿光电厂等机组低于1、10、20 mg/m3,舟山4号、三河4号机组实现"近零排放"后已稳定运行超过7年.研究"近零排放"煤电的经济性,分析"近零排放"的环境和社会效益,提出"近零排放"技术、标准和实践的哲学思考,展望清洁煤电绿色发展方向.燃煤发电"近零排放"技术和工程实践推动了我国环保标准的发展,标准提升促进了技术进步,基于我国国情持续推进煤炭清洁高效利用,不断提升环保标准,对保障我国的能源安全和可持续发展具有重要意义.

Improving the power generation efficiency of coal-fired units is an effective measure to achieve energy conservation and carbon reduction. The engineering application of 700 ℃ ultra-supercritical coal-fired power generation is hindered by the high price of superalloy materials; therefore, it is necessary to explore new layouts and structures to shorten the high-temperature steam pipelines and reduce the engineering costs. By taking the phase III expansion project—the world's first demonstration project of high-level layout—of the Jinjie coal-fired power plant as an example, this study introduces the engineering innovation practice of the high-level layout technology for an air-cooled ultra-supercritical steam-turbine generator unit. The results indicate that the reinforced concrete frame and shear wall structure can effectively lower the overall center of gravity and improve the seismic performance of the main power house, thereby ensuring the safety of the main power house structure, high-temperature steam pipelines, and steam turbine generator unit through technological breakthroughs. Compared with those of the conventional layout (its operating floor level being 12.6-17 m), the main steam and reheat steam pipelines of the high-level layout (its operating floor level being 65 m) can save 34.2% and 20.9% of raw materials, respectively; and exhaust steam pipes of the air-cooled island can save 93% of raw materials. Furthermore, the power supply coal consumption can be reduced by 4.5-5.1 g/(kW·h) compared with the design value, and the overall economical efficiency is significantly improved. The monitoring data after operation show that all parameters in the real-time on-line monitoring system of the main power house structure are within the safety threshold, and the plant structure and critical equipment are both in a safe state. Therefore, we propose to promote clean and efficient coal-fired power generation technologies and apply the high-level layout technology to the advanced air-cooled coal-fired power units in northeast, north, and northwest China as these regions are rich in coal but short of water. This can provide practical experience for the construction of economical high-temperature steam pipelines for 700 ℃ ultra-supercritical coal-fired power units.

China has established the largest clean coal-fired power generation system in the world by accomplishing the technological transformation of coal-fired power plants (CFPPs) to achieve ultra-low emission. The potential for further particulate matter (PM) emission reduction to achieve near-zero emission for CFPPs has become a hotspot issue. In this study, PM emission from some ultra-low emission CFPPs adopting advanced air pollutant control technologies in China was reviewed. The results revealed that the average filterable particulate matter (FPM) concentration, measured as the total particulate matter (TPM) according to the current national monitoring standard, was (1.67±0.86) mg/m3, which could fully achieve the ultra-low emission standard for key regions (5 mg/m3), but that achieving the near-zero emission standard was difficult (1 mg/m3). However, the condensable particulate matter (CPM), with an average concentration of (1.06±1.28) mg/m3, was generally ignored during monitoring, which led to about 38.7% underestimation of the TPM. Even considering both FPM and CPM, the TPM emission from current CFPPs would contribute to less than 5% of atmospheric PM2.5 concentrations in the key cities and regions in China. Therefore, further reduction in FPM emission proposed by the near-zero emission plan of CFPPs may have less environmental benefit than emission control of other anthropogenic sources. However, it is suggested that the management of CPM emission should be strengthened, and a national standard for CPM emission monitoring based on the indirect dilution method should be established for CFPPs. Those measurements are helpful for optimal operation of air pollutant control devices and continuously promoting further emission reduction.

采用EPA 29方法对国华寿光电厂2号1000MW超超临界燃煤机组污染物控制单元进行采样,开展了重金属污染物(As、Pb、Se、Cd)全流程监测.建立了包括气体/固体/液体中重金属的燃煤过程中质量平衡,并考察了重金属在机组中的富集与分布特征.结果表明:该机组烟气排放的重金属含量相对较低,100％负荷时As、Se、Pb、Cd排放浓度分别为1.11,0.59,0.33和0.01μg/m3,45％负荷时相关重金属排放和100％负荷接近.给出了不同负荷下各种重金属在燃煤机组的分布,燃烧后Pb、Se、Cd主要富集到飞灰中,但低负荷时底渣中Se和Cd的比例明显升高.APCDs中,ESP对烟气中As、Pb、Se、Cd四种元素的脱除率均达到了97％以上,不同负荷下WFGD和WESP对这些重金属具有深度脱除的效果.

汽轮发电机组高位布置技术可以缩短电厂高温蒸汽管道,是未来700℃超临界燃煤机组减少镍基合金材料使用的有效途径之一.但是汽轮发电机组高位布置技术在国际上尚无成功经验可参考,特别是汽轮发电机组基础的振动特性、抗震性能等有待深入研究.该文依托2×660MW汽轮发电机组高位布置工程,建立汽轮发电机组基础和主厂房结构的缩尺试验模型,采用三点空间激振、多点空间测量的方法分析了基础台板的自振特性,采用专业软件预测多点扰力共同作用下基础的强迫振动响应,并与数值分析结果和控制标准进行对比.结果表明,结构固有频率分布主要集中在20Hz以内,40Hz以后的高阶固有频率明显减少,这种分布为机组提供了较好的运行环境;在机组启动过程中尽量避开机组的临界转速频率,避开率超过10％;强迫振动下台板基础的扰力点和非扰力点的最大线位移、最大振动速度满足规范限值.通过合理设计台板基础下方的弹簧隔振系统,可较好控制汽轮机基础的振动.研究结果为汽轮发电机组高位布置工程设计提供了依据.

为探究中国超低排放燃煤电厂汞及其他有害痕量元素未来标准制定的可行性及建议,综合比对了中国与欧盟、美国等发达国家燃煤电厂大气痕量元素排放标准限值,并基于燃煤电厂现场测试相关文献调研分析,系统地评估了中国燃煤电厂汞及其他9种典型痕量元素(砷、铅、硒、镉、铬、锑、钴、镍和锰)的排放现状.结果表明:与美国、欧盟、加拿大等发达国家相比,目前我国燃煤电厂大气污染物排放标准限定的痕量元素污染物种类较为单一(仅规定了烟气汞及其化合物排放限值,≤30μg/m3)且排放标准限值较为宽松;在全国燃煤电厂已普遍完成超低排放升级与改造的新形势下,现行的《火电厂大气污染物排放标准》(GB13223-2011)已难以起到对燃煤电厂大气汞及其他痕量元素排放控制的实际限制作用和对先进新技术的示范引领作用.作为世界上的最大燃煤消费国,中国燃煤电厂每年消耗煤炭占中国煤炭消费总量的一半左右,是国际社会和《关于汞的水俣公约》重点关注的排放源.因此,推动燃煤电厂大气汞排放标准限值的修订及其他有害痕量元素排放标准的制定,对于保护生态环境和公众健康及国际履约均具有较大的可行性及重要的现实意义.

发展清洁高效燃煤发电技术是我国改善民生和建设生态文明的必然要求,也是现代化能源体系建设的重要组成部分.依托国华锦界电厂三期扩建工程的2×660MW超超临界、直接空冷发电机组,通过开展主厂房结构、汽轮发电机组弹簧隔振基础及主要蒸汽管道布置等技术研究,形成了完整的汽轮发电机组高位布置工程设计方案.相对于常规燃煤电厂布置,高位布置可以缩短高温蒸汽管道和汽轮机至空冷凝汽器间的排汽管道,节约管道材料成本,为700℃先进超超临界燃煤技术发展提供技术储备和先导工程.

神华煤储量丰富,具有低灰、低硫、中高热值、易燃等特性,存在灰熔点低,易结焦、爆炸等难题.从安全和清洁2个维度总结了神华煤安全燃烧、清洁利用技术及创新实践.分析了神华煤燃烧、结渣及掺烧特性,探讨了大容量锅炉结渣防治技术和燃烧系统设计、运行关键技术,提出了大容量煤粉锅炉燃用神华煤的炉膛设计选型准则,实现了神华煤型号标准化.提出了燃煤锅炉烟气污染物排放达到天然气燃气轮机组排放限值的“近零排放”企业标准,开发了除尘脱硫脱硝脱汞核心技术,率先在燃用神华煤的大容量锅炉上应用推广.结合50 000 m3/h燃煤烟气污染物全流程控制中试平台试验研究,形成了宽温度窗口脱硝、湿式机电耦合除尘等新技术,获得了烟尘,SOx,NOx和汞的排放特征及多污染物协同控制规律;通过燃煤锅炉示范应用,实现烟尘,SO2,NOx和汞排放质量浓度分别不高于1,10,20,0.003 mg/m3;探索并提出了“1123”生态环保排放限值,分析了燃煤烟气污染物减排效果.未来将持续开展新一代高效发电、烟气多污染物一体化脱除及资源化回收、非常规污染物深度脱除和CO2“近零排放”等技术的研发与应用.

针对燃烧后胺法脱碳工艺再生能耗高的问题,本文将机械蒸汽再压缩(mechanical vapor recompression,MVR)节能技术与胺法再生工艺集成,建立燃煤烟气胺法脱碳MVR再生系统.采用速率基非平衡模型,以再生能耗为目标函数,对影响再生系统能耗的关键工艺参数进行考察,分析其对MVR再生系统的影响规律.结果表明,MVR技术在燃煤烟气胺法脱碳再生系统中表现出良好的节能效果,但最终节能效率应低于41.3％;在0.35～0.55mol/mol范围内增加富液CO2担载量以及从90℃到115℃提升进塔温度,再生能耗快速降低;增加再生塔压力,MVR再生系统的再生能耗亦呈下降趋势,再生塔压力控制在2atm以下较为合适;降低闪蒸压力,压缩机能耗不断增加,再沸器能耗快速降低,闪蒸压力的合理取值区间为0.9～1.0atm;降低塔顶冷凝器温度从70℃到20℃,再生能耗略微增加,CO2气体纯度提高.

按照"安全高效、绿色环保、煤来灰去、清洁低碳"设计理念,以高寒地区建设露天无廊道、正向输煤、反向运灰的运输系统为研究目标,通过建立带式输送机弹性和黏弹性力学模型,应用动力学对带式输送机空载和满载启停进行动力仿真分析,验证集正向输煤、反向运灰、连续转载、同步运输、水平转弯技术于一体输送系统方案的可行性,设计应用多台变频器配置同步控制柜,增设输送带张力检测方式,实现长距离带式输送机驱动功率平衡与多点驱动控制.通过设计应用中转运灰带式输送机、回程带面槽角优化以及同步给料控制技术,实现多条带式输送机正向输煤、反向运灰、连续转载、同步运输的目的.通过设计采用"绞车+重锤塔架式"的拉紧方式,优化设计全封闭防雨罩,应用翻带技术、惯性转载技术、粉煤灰降尘技术等,实现对生态环保、防寒防冻、智能化等方面的独创性设计.按照缓冲系统、输煤系统、运灰系统及智能化系统4部分,设计并提出了"长距离、大运量、正向输煤、反向运灰、煤灰一体、连续转载、同步运输、多曲线水平转弯"的运输系统工程设计整体方案,攻克了高寒地区散状物料双向运输系统运行环境差、工程地形复杂、生态环保要求高、正向输煤、反向运灰、煤灰一体等技术研究与工程设计难题.

In this paper, satellite data from five isolated power plants were used to explore the change local emissions levels belonged to the vicinity of the power plant before and after ultra-low emissions (ULE) retrofitted. Sulphur dioxide (SO2) and nitrogen dioxide (NO2) observations from Ozone monitoring Instrument (OMI) satellite data were used to evaluate the emission changes of the power plants retrofitted by ULE technology. Meanwhile, the actual emission reduction effect of isolated power plants was evaluated by the OMI data. It was observed that the isolated power plants have shown obvious point source characteristics. The average annual SO2 emission reduction ratio of SZ, ZD, JJ, ND and BD power plants after ultra-low transformation is 43.7%, 56.9%, 29.0%, 34.6% and 26.8%, respectively, compared with that before the transformation, while the corresponding PBL-SO2 column concentration reduction ratio is 27.0%, 14.3%, 15.6%, 26.6% and 4.2%, respectively. The average annual NOx emission reduction ratio of the power plants after ultra-low transformation is 44.7%,79.3%,29.0%,73.2% and 29.8%, respectively, compared with that before the transformation, while the corresponding NO2 column concentration reduction ratio is 7.0%,27.2%,25.7%,8.9% and 5.6%, respectively. The trend of emission reduction before and after the ULE retrofitted of SO2 and NO2 column concentration by satellite observation is consistent with the calculated trend of emission reduction. Satellite observations have confirmed the emission reduction effect of ULE technology.

Modified fly ash is a potential competitive sorbent for flue gas mercury remove in coal-fired power plant. The adsorption characteristics of coal fly ash under different temperature and modification methods were studied. On-line modified fly ash as a sorbent for mercury removal at a coal-fired power plant was carried out. The results of laboratory show that the adsorption performance of a coupled bromide and mechanical modified fly ash was better than that of inherent fly ash and mechanical modified fly ash. Furthermore, it was found that high temperatures are more favorable for mercury adsorption. In a demonstration at a full-scale 1000 MW coal-fired power plant unit, injection of the bromide and mechanical modified fly ash resulted in a decrease of the total concentration of mercury emissions at the stack. Additionally, a decrease in Hg2+ from the SCR to the ESP was found. When injected modified fly ash, the final emission concentration of mercury at the unit outlet reached 1.15 mu g/m(3), with a mercury emission reduction efficiency of 56.1%.

综述了钙基吸收剂的循环捕集过程及CO2吸收性能衰减原因,从天然矿物原料、杂质含量少的化学试剂以及钙含量高的工业固废3个方面,总结分析了不同钙原料制备钙基CO2吸收剂的主要方式及改性效果.最后指出采用固废原料制备钙基吸收剂同样具有良好的CO2吸收效率和循环稳定性,并能大幅降低吸收剂的制备成本.

为提升固废磷石膏矿化固定CO2反应转化率、反应速率以及产品碳酸钙的纯度和白度,本研究首先利用磷石膏高效除杂技术获得净化石膏,再在加压条件下矿化固定CO2.采用XRF、XRD、SEM及白度分析仪等对净化石膏和产品碳酸钙以及碳酸化反应的转化率、反应速率进行比较分析.结果表明,通过高效除杂,磷石膏中几乎所有杂质都有效脱除.由于大幅消除了杂质对磷石膏解离以及碳酸化反应的不利影响,在净化石膏矿化固定CO2时,碳酸化反应的转化率从97.5％增加到99.5％,反应速率小幅增加,所得碳酸钙产品的纯度从86.5％增加到99.1％,白度从47.8％大幅增加到91.7％,且碳酸钙的晶型由方解石型转化为文石型.同时,本研究所得碳酸钙产品的纯度和白度显著增加,使其相应的附加值更高、用途更广,从而显著提升磷石膏矿化捕集CO2技术的经济性,为CO2的捕集并联产高品质碳酸盐产品,以及磷石膏的高效资源化提供新思路.

To develop supercritical circulating fluidized bed (CFB) boiler is objective of international CFB circles because supercritical CFB boiler combines the advantages of CFB combustion of low cost emission control and supercritical steam cycle of high efficiency of power generation.It is also most important for low rank coal utility.With the support of High Technology R&D Program (863) and Key Project of the National Research Program of China,Chinese researchers investigated systematically the issuers of supercritical CFB boiler development.And the huge theoretical and engineering challenges from 300MW subcritical natural circulation leaping to 600 MW supercritical once through are comprehensively broken.And the first 600MW supercritical CFB boiler and its auxiliaries were successfully developed and demonstrated in Baima Power Plant,Shenhua.Then the investigation results have been successfully expanded into 350MW supercritical CFB boilers design and have been commercialized widely.These studies provide the basis for the development of ultra-supercritical CFB boiler.Now,the key technologies such as heat deviation,ultra-low emission,and low electric power consumption are being investigated.And some preliminary achievements has been made.

针对神华集团典型“近零排放”燃煤机组,考察了大气污染物(烟尘、SO2、NOx、汞及其化合物)的排放特征,提出了更加契合绿色发展生态环保要求的燃煤电厂大气污染物排放限值,即烟尘、SO2、NOx和汞及其化合物排放限值分别为1、10、20和0.003mg/m3(简称“‘1123’排放限值”).评估了新建“近零排放”燃煤机组的长期运行排放状态,并研究了“近零排放”机组汞污染协同减排效果.结果表明,2017年1-10月新建机组烟尘、SO2、NOx排放质量浓度平均值分别在0.69～0.77、6.04～6.63、16.56～ 16.79mg/m3之间,排放绩效可低至0.0023、0.022、0.057 g/(kW·h),污染减排已达到国际领先水平;“1123”排放限值下烟尘、SO2和NOx的达标率分别超过92.06％、85.43％和77.46％,“近零排放”原则性技术路线可实现更好、更优的生态环保排放指标.燃煤机组通过“近零排放”技术改造,可提高烟气中Hg0的氧化效率和汞化合物的捕获效率,环保设施组合协同脱汞效率提升至75.3％～90.9％(平均值为82.8％±8.1％),汞排放水平降至0.51～1.45μg/m3[平均质量浓度为(0.94±0.47) μg/m3],基本达到国际先进煤电机组的协同控制水平.研究显示,清洁煤电大气污染物新排放限值总体上比GB 13223-2011《火电厂大气污染物排放标准》中燃煤电厂大气污染物排放限值小1个数量级,可为加快推进生态文明建设、制订先进的燃煤电厂大气污染物排放新标准提供科学依据.

The distribution rule of mercury speciation in the coal-fired flue gas is introduced.The research progress of post-combustion mercury removal technologies at home and abroad is reviewed emphatically.Furthermore,the adsorption and oxidation mechanism of elemental mercury for each technology are discussed.The results show that the existing pollution control facilities in coal-fired power plants have a certain synergistic effect on mercury removal and the synergistic control efficiency can be improved with the increase in percentage of oxidized mercury.The development of materials is extremely significant for the specialized mercury removal technologies.The adsorption efficiency and application potential of the materials for mercury removal,including carbon-based materials,non-carbon-based materials and coal-fired fly ash,are summarized and analyzed.In addition,the influences of the physicochemical characteristics of mercury removal materials,components of flue gas and surface active ingredients on mercury removal behavior and reaction mechanism are investigated.Meanwhile,further exploring the mechanism of mercury removal and optimizing the preparation/regeneration processes shall be the research emphasis in the future.

It is difficult to control the mercury pollution in coal-fired power plant, especially for elemental mercury. Thus, the development of mercury sorbent with high efficiency and low cost has been scientific and technological focus. Coal-fired fly ash modified with halide has low price and strong potential for mercury removal. However,the adsorption and oxidation mechanism of Hg0 on modified fly ash is unclear and still needs further study. This review systematically summarized the current state of knowledge associated with fly ash used as mercury sorbent on controlling flue gas mercury pollution. Then,the mercury removal behaviors on various factors were discussed, including physicochemical characteristics, flue gas components and halogen. The heterogeneous reaction on the surface active sites of unburned carbon and inorganic components was the key point of Hg0 oxidative removal. Furthermore, the merits and faults of unburned carbon and magnetosphere acted as carrier were analyzed. In addition, the influences of modifying agent and preparation method on direct modification of fly ash and the adsorption mechanisms on HBr-modified fly ash were discussed. Finally,future research directions were proposed,involving exploring the characteristics for Hg0 binding on the organic and inorganic portion of fly ash,and studying the reaction dynamic behaviors of Hg0 on the surface of multi-components through combination of quantum chemistry theory and macroscopic experimental investigation.

The state-of-the-art development of spatial correlation based wind speed prediction is reviewed.And the concepts of conditional correlation and its corresponding confidence correlation are introduced to improve traditional spatial correlation.Based on big-data thinking, a framework of integrating data-driven with causality-driven wind speed prediction is proposed.In the framework, correlation is mined from historical data for wind speed prediction.Spatial correlation is employed to import data sources for wind speed prediction to overcome the shortage of historical data in part.Furthermore, spatial correlation with long time lag can be used to predict drastic and sudden change in downstream wind speed.Finally, suggestions for future research under the proposed framework can be made with confidence.

The formation/conversion mechanism of ammonium sulfate salts and the influences of ammonia slip on the emission characteristics of PM2.5 from coal combustion are reviewed emphatically.In addition,the influences of ammonia slip,SCR operating parameters and flue gas components on the formation characteristics of ammonium sulfate salts are described,and the effect of ammonia slip on the safety operation of on-way devices are analyzed.Finally,this paper predicts the future research direction for ammonia slip and deep reduction of emission of fine particulate matters derived from slipped ammonia,and points out that it is significant to explore the migration and transformation regulations of ammonium sulfate salts in the flue gas-air system and realize active control on ammonia slip.