U.S. sulfur dioxide emission reductions: Shifting factors and a carbon dioxide penalty

For more than 20 years, the large-scale application of flue gas desulfurization technology has been a dominant cause of SO₂ emission reductions. From 1994–2004, electricity generation from coal increased, but the shift to low-sulfur coal eclipsed this. From 2004–2014, electricity generation from coal decreased, but a shift to higher-sulfur subbituminous and lignite coal overshadowed this. The shift in coal quality has also created a CO₂ emissions penalty, representing 2% of the sector’s total emissions in 2014.     

二氧化碳和常规污染物协同减排研究

以2007年能源-环境-经济投入产出表为依据,得到能源环境完全消耗系数表,基于此分析火电行业采取提高可再生能源发电比重、淘汰小容量机组、发展清洁能源、发展热电联产、污染物末端治理等措施后,CO2、SO2、COD、工业固体废弃物、NOx等生成量的变化,并对其协同减排度进行了计算.指出目前优化能源结构和优化燃煤发电结构是火电行业CO2和各种污染物减排的根本措施.     

基于边际发电成本的联络线交换功率两阶段迭代优化方法

为充分利用联络线功率输送能力,降低电网总体运行成本,提出一种基于边际发电成本的联络线交换功率两阶段迭代优化方法。从各区域电网初始机组组合方案与各联络线初始交换功率出发,分两阶段对联络线交换功率进行迭代优化。首先,在不改变机组开机方式的前提下,基于各区域电网的边际发电成本对联络线交换功率进行第一阶段迭代优化。接着,对区域电网中出力连续等于最小技术出力且发电成本最高的边际机组进行关机操作,在此基础上进行第二阶段迭代优化。该方法与电网实际调度过程联系紧密,且仅需各区域电网提供边际机组的运行信息,保护了各区域电网的数据隐私。最后,基于3个区域电网和3条联络线的仿真实验验证了所提模型和方法的有效性。     

A method for evaluating effects of energy efficiency improvement on carbon dioxide emission reduction

Global warming due to increasing atmospheric carbon dioxide (CO₂) is a matter of serious concern. Energy efficiency improvement has been considered to be the most effective strategy for reducing CO₂ emissions. The acceleration of R&D for energy technologies which have large effects on CO₂ emission reduction should be effective in abating global warming. In this study, the author proposes a method for evaluating the effects of energy efficiency improvement on CO₂ emission reduction. This method utilizes a compact energy system model combined with analytical calculations. Using this method, effects of energy efficiency improvement in Japan in the year 2030 are analyzed. Energy efficiency improvement in thermal power generation, nuclear power generation, and heat utilization are especially effective for reducing CO₂ emissions. The author estimates that CO₂ emissions per capita can be stabilized at the present level by energy efficiency improvement.     

利用PCM设备组网功能优化电力通信网络

根据佛山地区电力通信网的实际情况,提出了发挥PCM设备组网功能,优化电力通信网络的要点.一方面,通过对PCM设备电路保护功能的分析,提出对PCM设备进行组网成环改造;另一方面,通过对多方向交叉连接PCM设备和64 k数字交叉连接设备组网的讨论,提出引入64 k数字交叉连接设备进行PCM设备组网优化.通过一系列的优化改造工作,提高了电力通信网络的稳定性和可靠性,简化了网络和管理,取得了良好的效果.     

A comparative thermodynamic analysis of alternative technologies for using coal in a combined-cycle plant with minimization of emissions of carbon dioxide into the atmosphere

We consider the problem of reducing the amount of carbon dioxide emitted into the atmosphere when using coal at power stations. A comparative thermodynamic analysis of different methods for entrapping carbon dioxide during the combustion of coal in steam-turbine units and combined-cycle plants is carried out. The levels of reducing CO₂ emissions achieved using different technologies for entrapping it are compared, and the resulting loss in the thermal efficiency of power installations is analyzed.     

A knowledge-based approach to optimize switching in substations

Automatic sequence switching has been an important pursuit in the field of substation automation. An intelligent approach to the optimization of switching sequences in electric substations is presented. The optimal sequence switching problem is stated. A knowledge-based model of a substation switch network organized in a trilevel hierarchical structure is suggested, and a set of basic techniques suitable for the general task of network reorganization is given. An intelligent optimal sequence switching strategy for substations based on modeling techniques is presented. An expert system in Prolog used to formalize the sequence of switching operation and application in substations is described     

A comparative technical and economic analysis of different alternatives for using coal in a combined-cycle plant with minimal emission of carbon dioxide into the atmosphere

We consider the technical and economic aspects of a problem related to reducing the amount of CO₂ emitted when coal is burned at thermal power stations. The additional costs associated with different technologies for entrapping carbon dioxide produced when coal is burned in steam-turbine units and combined-cycle plants (which are the main types of power-generating installations) are analyzed by way of comparison. The specific cost of removing carbon dioxide using different technologies for its entrapment is estimated.     

超临界二氧化碳压缩机非平衡冷凝研究进展

压缩机是超临界二氧化碳（S-CO2）动力循环系统的核心设备,其工作在S-CO2的近临界区域,因此S-CO2工质在压缩机内流动时易发生非平衡冷凝,影响系统性能与可靠性。压缩机内部的S-CO2非平衡冷凝实验观测难度大,数值模拟复杂,相关S-CO2压缩机设计经验也较为缺乏。本文结合近年研究成果,从研究方法、数学模型和实验研究等角度总结了目前S-CO2非平衡冷凝的研究进展,指出了需进一步开展的研究方向,如改变喷管几何结构参数,从而改变成核区体积,以改变流体在亚稳态区的滞留时间;改进气体状态方程进而提高亚稳态区域热物性精度,从而准确进行数值模拟;在设计S-CO2压缩机时,利用实验测得的Wilson线设定压缩机进口条件,构建新的安全边界等。     

对直接法测定水中二氧化碳方法的探讨

针对采用直接法难于准确测定水中二氧化碳含量的问题,在对一级除盐系统除碳器效率的测定试验中,分别采用SS—13—1—84直接法和SS—13—2—84固定法进行对比试验。结果显示：电力工业水、汽试验方法规程中SS—13—1—84直接法测定水中游离二氧化碳的方法对于具有较强酸度的水样,如阳离子交换器出水,通过改进试验条件,并按照SS—6—1—84标准的要求进行强酸酸度校正,是同样可以适用的。     

电力系统碳排放核算综述与展望

碳核算能量化分析碳排放数据,对实现“双碳”目标至关重要。从直接、间接两个角度出发,聚焦电力系统碳排放核算问题。直接碳排放主要源于源侧火电机组和电网侧SF₆气体泄露。首先对火电机组碳排放核算方法及研究概况进行综述,围绕特性、精度、适用范畴等,对排放因子法、物料平衡法、实测法进行分析对比,并简要说明了由SF₆气体泄露造成的等价碳排放核算方法。其次,基于发电负荷等于厂用电负荷、网损及综合用电负荷三者之和这一关系,提出间接碳排放的定义,厘清直接、间接碳排放关系,并比较平均碳排放因子法与基于碳排放流理论核算间接碳排放方法的优劣。最后,分析新型电力系统中直接、间接碳排放的影响因素,并展望未来考虑市场因素下的碳排放核算方法。     

电力行业碳排放权的初始分配机制

在传统碳排放权分配模式的基础上,结合我国电力行业发展的实际情况以及发电资源分布的特点,提出基于区域比较的两级分配机制,并建立相应的分配模型。该分配机制中,一级区域间分配考虑各区域发展的不平衡性和发电资源分布的不均衡性,保证分配的公平性;二级区域内分配以发电效率和效益为主,保证分配的高效性。仿真结果表明该分配机制能合理分配碳排放权。     

High-field single electron emission rates and their influence onthe Paschen characteristics in compressed gases

By means of a newly developed statistical avalanche counting technique which enables high-field, single electron emission rates (SEERS) to be measured from unsparked freshly prepared surfaces having various thicknesses of oxide film, it is established for the first time that SEERS increases, for a given electric field, with an increase in the bulk modulus (hardness) of the material cathodes; also remarkably the thicker the oxide layer, the higher the SEERS. These trends are reflected in the Paschen sparking characteristics which show that the gaseous electric strength decreases with increase in the bulk modulus and increase of oxide layer thickness of the cathode material; and thus the increase in SEERS. This former trend is opposite to that established more than forty years ago. Other hitherto unobserved phenomena like a gas pressure effect, switching from a low to a high electron emission mode and vice versa, the influence of deliberate sparking and the total absence of spark conditioning are reported. Analysis of SEERS by the more successful Richardson-Schottky rather than the Fowler-Nordheim equation shows that the low electric field intensification factors derived increase with the bulk modulus of the cathode material and ultimately are determined by the polishing procedure     

双碳目标下NB-IoT能源物联网安全构架及关键技术

围绕NB-IoT能源物联网安全构架及关键技术，分析了“双碳”目标下能源系统新特征，从绘制碳足迹、优化能源供给、优化能源交易和构建双向信息流四个方面剖析了能源物联网对“双碳”目标的支撑作用。总结了“双碳”目标下能源物联网的特性及需求，归纳了以NB-IoT 为代表的LPWAN与能源物联网的匹配关系。探索构建了包含NB-IoT物联网安全模组和安全服务平台的能源物联网安全构架。重点分析了基于eSIM+ESAM NB-IoT的物联网安全模组硬件、基于GlobalPlatform可信框架的NB-IoT物联网安全模组软件，以及基于区块链的物联网卡全链条安全管理关键技术。该技术可为能源生产、传输、存储、交易和消费领域提供安全、可信的LPWAN物联网解决方案，为构建清洁低碳、安全高效的能源体系提供可信数据支撑，助力“3060双碳目标”实现。     

开裂混凝土中碳钢与不锈钢钢筋腐蚀速率研究

为了揭示裂缝宽度对混凝土中碳素钢与不锈钢钢筋锈蚀速率的影响,本文在钢筋腐蚀电化学理论的基础上,考虑裂缝对混凝土中氯离子和氧气输运的影响、氧气对钢筋锈蚀的作用,建立开裂混凝土数值模型探究了钢筋的腐蚀过程。通过与试验结果的对比分析验证了数值模型的正确性,并以此为基础开展了参数敏感性分析。研究结果表明：阳极极化过程和氧气供给是影响钢筋腐蚀速率的两大制约因素,裂缝除了能够提前钢筋由钝态转化为腐蚀态的时刻,也会对碳钢腐蚀稳定后的腐蚀速率大小产生影响,减小裂缝宽度和氯离子扩散系数能有效限制钢筋的腐蚀速率。与碳素钢筋相比,即使在更恶劣的侵蚀条件下不锈钢钢筋仍表现出了更好的耐蚀性能。     

采用超临界二氧化碳动力循环回收燃气轮机排气余热的系统优化研究

采用超临界二氧化碳(S-CO2)动力循环回收燃气轮机排气余热可以提高系统性能,增加系统灵活性,减小系统体积.为此,本文采用遗传算法,以Taurus 60燃气轮机排气为热源对4种S-CO2动力循环构型进行优化.结果 表明,采用高、低温2级加热器布置的循环构型4输出净功最高,为3.20 MW,和单独的燃气轮机相比,可使系统...     

超临界二氧化碳燃煤发电系统低温余热回收的技术经济性优化

现有超临界二氧化碳(S-CO₂)燃煤发电系统锅炉排烟温度为120℃左右。通过系统优化降低锅炉排烟温度,有望进一步提高燃煤发电系统效率和烟气除尘效率。为此,本文以1 000 MW S-CO₂燃煤发电系统为例,通过回热系统、烟气冷却系统和空气预热系统的耦合优化,提出了带有低温烟气余热回收系统的改进构型;建立了热力学和技术经济性分析模型,以技术经济性最优对构型进行了优化分析。结果表明:采用烟道旁路、低温省煤器及主压缩机中间冷却的改进构型4,可将排烟温度降低至约95℃,与基础构型相比,可提高锅炉效率1.5%,提高电厂效率1.45%。通过分析燃料成本和运行时间对度电成本的影响,证明改进构型4的度电成本最低,经济性效果最好。     

超临界二氧化碳环境下耐热钢T91腐蚀行为机理研究

超临界二氧化碳循环发电系统具有效率高、设备体积小和用水量小等优点,其应用前景广阔,该系统高温部件结构材料的抗腐蚀性能是确保系统长周期安全高效运行的决定因素之一。本文在超临界二氧化碳环境下开展高温部件典型材料耐热钢T91的腐蚀机理试验,利用X射线衍射仪、扫描电子显微镜和辉光放电光谱仪分析耐热钢T91表面腐蚀产物类型、成分及其分布。结果发现:在试验条件下超临界二氧化碳环境中,耐热钢T91腐蚀动力学规律符合抛物线型腐蚀规律,说明腐蚀过程受离子扩散控制;耐热钢T91腐蚀的主要类型为全面腐蚀,并且腐蚀产物表面出现C富集现象;耐热钢T91表面的腐蚀产物从气固界面到基体依次为Fe3O4、(Fe,Cr)3O4与碳化物和弥散于基体的碳化物;超临界二氧化碳环境中腐蚀产物(Fe,Cr)3O4层与耐热钢T91基体出现渗碳现象,说明腐蚀过程中发生氧化和碳化反应,研究结果丰富了超临界二氧化碳腐蚀中C元素的演变规律。     

基于二氧化碳工质的回热器振荡流实验与模拟研究

采用二氧化碳气体作为斯特林发动机内部循环工质可以实现机器长时间运行,降低成本。为探究二氧化碳工质在回热器中的流动特性,完善斯特林循环分析方法,更好地设计和优化基于二氧化碳工质的斯特林发动机,本文基于CFD方法建立了有限体积模型和振荡流模型,并搭建了振荡流实验台进行实验验证,获得了二氧化碳在金属丝网回热器中的压降、摩擦特性和流阻关联式。随后发现热吹和冷吹过程中流阻关联式的差异较大,在高雷诺数下（1 733＜Re＜3 587）二氧化碳和空气流阻关联式差异小于10%,在低雷诺数下（Re＜1 733）两者相差超过10%。此外,对二氧化碳工质循环率进行了修正,拟合得到了循环率与频率和目数的定量关系式。该流阻关联式和循环率可为优化回热器设计、完善斯特林循环分析方法提供理论支持。