集成小型堆和可再生能源的超临界CO2循环发电系统

  [目的]  小型模块化压水堆(小型堆)核电站由于温度参数低,其发电效率不到30%,为了提高小型堆的核能利用效率,可将小型堆与可再生能源组合,并以先进的超临界CO₂循环作为热能转换为电能的装置。  [方法]  基于简单回热模式的超临界CO₂循环,并在此基础上增加一次间冷和一次再热,将小型堆与太阳能、生物质能热源集成为新型混合发电系统,对其发电效率进行了分析。  [结果]  结果表明:对于高压透平入口温度390 ℃的系统,发电效率34.13%,对于高压透平入口温度550 ℃的系统,发电效率41.22%。此外,对系统的安全性分析表明:CO₂本身是具备核安全属性的工质,并且超临界CO₂循环还可以作为反应堆的非能动余热排出系统,确保在严重事故工况下,反应堆持续排出衰变热。  [结论]  集成小型堆和可再生能源的超临界CO₂循环发电系统具备良好的发电效率和核安全性。     

基于超临界CO2朗肯循环的太阳能光热发电系统分析

基于太阳能光热发电原理,提出加装回热系统的发电系统模型,结合朗肯循环,以超临界CO₂作为工质,系统分析进气温度、进气压力对发电系统效率的影响,研究回热系统的热经济性。结果表明：低压状态下进气压力对发电系统循环效率的影响较大,高压状态下进气温度对发电系统循环效率的影响较大;压力增大时,发电系统效率先增后减,温度增加时,发电系统效率保持增加;与无回热系统相比,加装回热系统能够明显提升发电系统循环效率;发电系统的不可逆损失随着压力的升高而降低,随着温度的升高而升高,为基于超临界CO₂朗肯循环的太阳能光热发电提供参考。     

超临界CO2发电系统循环参数优化设计方法

基于超临界二氧化碳简单循环发电系统热力学模型,对在多工艺参数综合影响下循环效率的变化规律进行研究。结果表明：当系统最高压力低于临界值时,循环效率随入口压力的增加而降低,随入口温度的增加先增加后降低;当系统最高压力大于临界值时,循环效率随入口压力的增加先增加后降低,随入口温度的增加而降低。通过分析循环效率随压缩机入口参数变化规律发生转变的原因,提出循环最高压力临界值的计算方法,提出并验证一种超临界二氧化碳简单循环参数优化设计方法,可显著提高循环参数寻优效率。     

洁净的燃气-蒸汽联合循环发电

介绍燃气 -蒸汽联合循环发电的特点、最新发展情况以及发展的前景     

3MW超临界CO2透平平衡活塞结构优化研究

采用文献中经过试验验证的最新研究成果,开展3MW等级超临界CO₂透平平衡活塞结构参数优化。进行一维计算,确定平衡活塞迷宫密封方案。选取3种结构方案进行三维CFD计算。一维与三维结果对比分析表明,超临界CO₂迷宫密封一维优化计算方法准确,平衡活塞结构可用于工程设计。     

利用燃气—蒸汽联合循环改造老电厂

利用燃气－蒸汽联合循环对老电厂进行改造,能够提高能源的综合使用率,降低能耗,并有效利用老电厂的现有设备,可以减少投资并见效快,文章对利用燃气－蒸汽联合循环对老电厂进行改造的主要方式和热效率进行了分析。     

洁净的燃气—蒸汽联合循环发电

介绍燃气-蒸汽联合循环发电的特点,最新发展情况以及发展的前景。     

以S - CO2为底循环工质的燃气联合循环系统优化

建立以超临界CO_2为底循环工质的联合循环系统,对比分析再压缩循环系统、部分加热循环系统、预压缩循环系统的性能参数,计算表明再压缩循环系统的效率最高。以再压缩循环为基础建立再压缩+简单循环和再压缩+部分加热循环模型,功率和效率比再压缩循环都有相应提高。对再压缩+部分加热循环进行性能参数优化,得到最佳运行工况点。     

联合循环发电现状

联合循环发电现状［日本］小岛民生１．前言大型联合循环发电正式用于日本的电力事业，已有近十年的历史。东京电力富津火电１号和２号机组、东北电力东新泻火电３号机组、中部电力四日市火电４号机组等，投运以来，运行成绩优良，热效率和负荷变化率都大大超过了由锅炉和...     

混合工质ORC耦合CO2跨临界发电系统性能研究

为了实现低温热能的充分回收利用,在混合工质ORC循环发电基础上,提出一种利用CO_2跨临界循环与其耦合的发电系统。基于热力学第一、第二定律,建立相应热力学模型,并编写计算程序,确定系统运行条件,分析蒸发温度T1、跨临界蒸发压力p01及热源温度T_g等参数变化对耦合系统性能的影响,并将其与采用相同混合工质的ORC系统进行比较。结果表明:随蒸发温度提高,跨临界循环部分输出功逐渐增加,而ORC部分由于冷凝温度提升所减少的输出功逐渐降低。在T_g为373.00K时,若T_1为340.00、354.00K,耦合系统较基本ORC系统输出功分别增加15.77、113.53kW。随跨临界蒸发压力p_(01)变化,耦合系统输出功及效率均有先减小后增加再降低的规律,存在一最佳跨临界压力,且表现为随热源温度降低,耦合系统性能优越性逐渐明显。若T_g为373.00或403.00K,则耦合系统较基本ORC系统分别增加19.16、7.18kW。在蒸发温度较高或热源温度较低时,采用耦合系统具有重要意义。     

天然气联合循环电厂燃烧后CO2捕集一体化技术经济评价

目的  近年来,天然气发电在我国构建清洁能源体系中扮演着重要角色,预计到2025年“十四五”规划期结束时,中国气电装机容量将会突破150 GW。二氧化碳捕集利用是气电实现“双碳”目标的关键路径之一。 方法  为此,设立1个600 MW等级天然气联合循环发电（NGCC）、1个CO₂捕集和压缩（PCC）的综合工厂作为模拟对象。 结果  模拟研究表明：设计CO₂全烟气量捕集、90%效率、CO₂压缩提纯率为99.5%,燃气发电总出力输出下降了约16.05%,厂用电率增加5.55%,循环冷却水需求增加了约50.52%。 结论  通过经济分析显示,综合工厂的静态投资成本比单一发电厂的成本高54.28%,电力均等化运营成本（LCOE）增加了15.96%,给二氧化碳捕集的部署和发展带来了非常大的困难。但其中天然气价格仍然是影响电厂运营成本的最主要因素。     

Hydrogen permeation through a Pd-based membrane and RWGS conversion in H2/CO2, H2/N2/CO2 and H2/H2O/CO2 mixtures

This study investigated the effect of gases such as CO₂, N₂, H₂O on hydrogen permeation through a Pd-based membrane −0.012 m² – in a bench-scale reactor. Different mixtures were chosen of H₂/CO₂, H₂/N₂/CO₂ and H₂/H₂O/CO₂ at temperatures of 593–723 K and a hydrogen partial pressure of 150 kPa. Operating conditions were determined to minimize H₂ loss due to the reverse water gas shift (RWGS) reaction. It was found that the feed flow rate had an important effect on hydrogen recovery (HR). Furthermore, an identification of the inhibition factors to permeability was determined. Additionally, under the selected conditions, the maximum hydrogen permeation was determined in pure H₂ and the H₂/CO₂ mixtures. The best operating conditions to separate hydrogen from the mixtures were identified.     

Explosion behavior of CH4/O2/N2/CO2 and H2/O2/N2/CO2 mixtures

In this work, the explosion behavior of stoichiometric CH₄/O₂/N₂/CO₂ and H₂/O₂/N₂/CO₂ mixtures has been studied both experimentally and theoretically at different CO₂ contents and oxygen air enrichment factors. Peak pressure, maximum rate of pressure rise and laminar burning velocity were measured from pressure time records of explosions occurring in a closed cylindrical vessel. The laminar burning velocity was also computed through CHEMKIN–PREMIX simulations.     

High performance composite hollow fiber membranes for CO2/H2 and CO2/N2 separation

The search for a clean energy source as well as the reduction of CO₂ emissions to the atmosphere are important strategies to resolve the current energy shortage and global warming issues. We have demonstrated, for the first time, a Pebax/poly(dimethylsiloxane)/polyacrylonitrile (Pebax/PDMS/PAN) composite hollow fiber membrane not only can be used for flue gas treatment but also for hydrogen purification. The composite membranes display attractive gas separation performance with a CO₂ permeance of 481.5 GPU, CO₂/H₂ and CO₂/N₂ selectivity of 8.1 and 42.0, respectively. Minimizing the solution intrusion using the PDMS gutter layer is the key to achieving the high gas permeance while the interaction between poly(ethylene oxide) (PEO) and CO₂ accounts for the high selectivity. Effects of coating solution concentration and coating time on gas separation performance have been investigated and the results have been optimized. To the best of our knowledge, this is the first polymeric composite hollow fiber membrane for hydrogen purification. The attractive gas separation performance of the newly developed membranes may indicate good potential for industrial applications.     

Efficiency of an Integrated Gasification Combined Cycle (IGCC) power plant including CO2 removal

This study is devoted to technical evaluation of a carbon dioxide removal in an existing Integrated Gasification Combined Cycle (IGCC) plant. This IGCC case is based on an oxygen blown entrained flow gasifier operating at 27 bar, the removal of acid gas (H₂S) is performed with MDEA unit, the efficiency of this IGCC is 43% based on the low heating value (LHV) of coal. A carbon dioxide separation unit conveniently integrated in a pre-combustion separation process is chosen, in order to take advantage of the high pressure of the gas. The methanol process for carbon dioxide removal is integrated downstream the existing desulfuration unit, and after a CO shift conversion unit. In this study, the integration of the CO₂ capture process to the IGCC is simulated as realistically as possible. The design parameters of both the gas turbine (the turbine inlet temperature, compressor pressure ratio, reduced flow rate) and the steam turbine (Stodola parameter) are taken into account. Maintenance of low _NOx${\mathrm{NO}}_x$ production in the combustion chamber is also considered. The production of _NOx${\mathrm{NO}}_x$ is supposed to be influenced by the low heating value of the gas which is maintained as low as for case of the synthesis gas without CO₂ capture. Thus the choice is made to feed the gas turbine of the combined cycle with a diluted synthesis gas, having similar low heating value than the one produced without the CO₂ capture. Plant performances for different conversion and capture rates are compared. A final optimized integration is given for 92 mol% CO conversion rate and 95 mol% CO₂ absorption rates, a comparison with former studies is proposed.     

单位电量CO_2排放强度与单位产值CO_2排放强度关系初探

电力单位产值CO2排放强度是全国单位产值CO2排放强度的重要组成部分,其既与电力行业排放绩效即单位发电量CO2排放强度有关,也与全社会能源效率、电气化水平、资源与市场情况等因素相关。本文系统分析了有关指标的统计特征、国际对比、影响因素及趋势预测,指出"十二五"及"十三五"期间,不论是单位电量CO2排放强度,还是电力单位产值CO2排放强度,其下降幅度都是有限的,需要理性看待并科学设置规划指标。     

塔式太阳能-超临界CO2发电系统集成与优化

  [目的]  传统塔式太阳能热发电效率较低,采用超临界CO₂（sCO₂）布雷顿循环集成太阳能发电可有效提高系统效率。  [方法]  采用联立方程法建立塔式太阳能集热发电（CSP）和sCO₂布雷顿循环集成系统的非线性规划数学模型以辅助系统分析与优化。模型包含太阳能集热子系统、sCO₂布雷顿循环以及高精度CO₂状态方程的约束,无需调用外部CO₂物性数据,可实现对集成系统任意数量的设计变量的同步优化。将模型应用于塔式CSP与sCO₂简单回热布雷顿循环和再压缩布雷顿循环系统的案例研究,优化系统并分析设计变量对系统效率的影响。  [结果]  研究结果表明:集成再压缩循环系统最大热效率达29.4%,高于简单循环系统的24.9%。再压缩循环的最优透平入口温度为901 K、最优膨胀比约为3;简单循环的最优透平入口温度为826 K、最优膨胀比皆大于3.2。  [结论]  系统存在最优的透平入口温度,提高透平入口温度可提高系统效率,但过高的温度会导致系统效率下降;系统存在最优膨胀比,膨胀比对集成再压缩循环系统的热效率影响较小,但对集成简单循环系统效率的影响较大。