基于乙醇胺碳捕集及氨法脱硝的太阳能-燃煤机组热力系统热经济性分析

针对火电机组燃烧后碳捕集解吸能耗及脱硝系统液氨蒸发器蒸汽消耗对燃煤机组热力性能影响的问题,研究醇胺法吸收CO2的机理,建立CO2解吸能耗模型;研究液氨脱硝机理,建立蒸汽消耗模型。提出以太阳能热为碳捕集系统解吸提供热源、机组抽汽为脱硝系统提供热源的一体化集成系统。基于热经济学结构理论,建立集成系统中组件的热经济学成本数学模型;研究系统中各组件成本增长的原因及燃料价格波动对组件性能的影响。研究结果表明:乙醇胺吸收剂解吸能耗为4.5 MJ/kg CO2;脱硝系统蒸汽消耗为0.25 t/h;集成系统的热效率比原系统提高1%;组件效率及组件比不可逆是影响集成系统中组件单位成本的主要因素;热经济学成本主要影响因素为比不可逆成本和设备投资成本;影响太阳能集热场热经济学成本的主要因素为太阳能集热场投资成本、比负熵成本和比不可逆成本;煤价波动对发电成本的影响较大。     

1000MW机组热力设备的热经济学分析

基于热经济学结构理论,对1 000MW机组进行了炯分析和热经济学建模.利用PowerBuilder9.0语言编制的程序计算了(火用)损、(火用)效率、炯损失系数、单位炯成本及单位热经济学成本等参数,得到了不同设计工况下各组件(火用)损、炯效率及(火用)损失系数的变化规律;计算了100％ THA设计工况下各组件的产品单位(火用)成本及有无非能量费用时组件的单位热经济学成本,并指出了对热力设备进行改造的方向,找到了机组设计环节的缺陷.结果表明,能量成本与热经济学成本比值大的设备,应侧重于技术改造,反之要适当降低非能量费用.     

基于结构理论的燃料价格波动对火电机组热经济性的影响研究

阐述了热经济学结构理论并以某600MW火电机组为例,绘制出热力系统的物理结构图和生产结构图,建立了基于燃料-产品定义的热经济学模型和炯成本模型.针对各个组元建立了特征方程,分析了各个组元的(火用)耗特点;定量分析了机组在额定工况下燃料价格变化对各个设备的热经济性及发电成本的影响.研究表明:煤价是影响发电企业发电成本的主要因素,系统生产过程前端组元的热经济学成本变化率比位于生产过程后端的组元小,因此燃料价格上涨对位于系统生产过程中末端组元的影响更大.     

600MW凝汽机组变工况热经济学分析

以600MW凝汽式机组为热经济学研究对象,使用热经济学结构理论,建立了系统的热经济学成本模型,计算变工况下各个组元的单位(火用)成本,并与传统的(火用)分析法进行比较,定量分析了变工况下组元单位(火用)成本的分布规律,指出了在系统节能分析中应重点考虑的组元,同时定性分析了组元单位(火用)成本高的原因.利用结构理论和等效焓降分别计算热耗率和煤耗率,验证了结构理论的合理性.结果表明:相对于(火用)分析法和等效焓降法,采用热经济学结构理论能更准确、更合理地判断设备的节能潜力.     

基于热经济学矩阵模式的发电厂热力系统经济性分析

对热经济学分析方法进行简要介绍,运用热经济学矩阵模式对某300MW机组进行热经济性分析,得出机组在设计工况下的单位(火用)成本和热经济学成本,并对机组热力系统性能进行评价,指出机组在运行中需要重视的热力设备.     

太阳能-碳捕集机组热经济学分析及生命周期评价

碳捕集和封存是实现电力低碳化发展的关键所在,建立太阳能辅助碳捕集系统与燃煤机组的耦合系统,构建耦合系统的热经济学优化模型,研究碳捕集机组的热经济性。构建碳捕集机组的生命周期评价体系,研究燃煤机组和碳捕集机组建设、运行、退役等各阶段的CO_2排放特性,对比分析其对环境的影响特性。结果表明:脱碳率为85%,吸收剂质量分数为30%时,解吸能耗为4.5 GJ/tCO_2,碳捕集机组优化前后的热效率分别为38.2%和39.3%。燃煤机组电厂运行阶段碳排放量所占比重约为99.4%,电厂建造、煤炭运输及电厂退役等阶段排放的CO_2比重约为0.6%。碳捕集系统建造、运行和退役增加的CO_2排放量为56.314 t/h,占耦合系统全生命周期排放总量的58.01%,减排率约为52.65%。碳捕集机组和太阳能辅助碳捕集机组中CO_2的排放由原燃煤机组的3.63×10~(-5)标准当量降低为1.72×10~(-5)和0.98×10~(-5)标准当量。燃煤机组、碳捕集机组和太阳能辅助碳捕集机组中,酸化对环境的贡献分别为1.5×10~(-6)标准当量和1.9×10~(-6)和1.0×10~(-6)标准当量,固体废弃物对环境的贡献分别为2.76×10~(-5)标准当量和3.52×10~(-5)和1.97×10~(-5)标准当量。     

基于碳捕集的太阳能-燃煤机组热力系统性能分析

针对碳捕集系统对燃煤机组热力性能方面的影响,以600 MW超临界汽轮机组为研究对象,研究燃烧后碳捕集的再生能耗,提出基于碳捕集的太阳能辅助燃煤机组热力系统集成方案,阐述该集成系统碳捕集的工作原理和吸收机理,对比分析太阳能碳捕集集成系统较传统碳捕集系统在热力性能方面的优势。利用系统灵敏度分析法,计算太阳能集热器价格波动时在成本上与之相抗衡的煤价,为实际中燃煤机组碳捕集集成方式的选定提供依据。结果表明:在碳捕集率为85%,日照辐射强度为500 W/m~2,其他参数相同的情况下,太阳能碳捕集系统和传统燃煤碳捕集系统的热效率分别为43.604%和38.238%,按太阳能市价1800$/m~2计算,太阳能-燃煤机组碳捕集电站的发电成本为0.5577$/(k Wh)。     

基于符号(火用)经济学的冷热电联供产品成本分摊

以南京热电厂600 MW供热机组为实例,采用热力学中的(火用)流与经济学中的成本相结合的符号(火用)经济学的理论和方法,建立冷热电三联供计算模型,得出热电厂的冷热电三联供的成本分摊.该模型在3种产品形成的过程中,考察(火用)流数值的变化,不仅考虑了3种产品的(火用)含量,还深入分析了产品在形成的过程中各自所造成的(火用)损,结合以(火用)定价,确定产品的(火用)成本,并与以热量法计算得出的成本进行比较.计算结果和分析表明,符号(火用)经济学运用于冷热电三联供系统切实可行,为3种产品的合理定价奠定了基础,有利于冷热电三联供系统的可持续发展.     

火电机组回热系统[火用]损分布的通用矩阵方程

根据[火用]平衡方程，首次导出了火电机组回热系统[火用]损分布的通用矩阵方程。利用这一方程可方便地得出不同机组回热系统的[火用]损分布规律，同时这一方程也为建立回热系统乃至整个机组与[火用]损分布通用矩阵方程相关的通用的[火用]分析模型、[火用]经济学分析模型、[火用]经济学优化模型和[火用]经济学故障诊断模型奠定了基础。利用这一方程还可以方便地开发出实时监测回热系统[火用]损分布的计算机程序，为降低机组能耗提供一个实用化的分析工具。图3表1参6     

1000MW超超临界二次再热机组热经济学分析

以1000MW超超临界二次再热机组为热经济学研究对象,将热力系统划分成若干个子系统,并绘制出机组热力系统的物理结构图和生产结构图,然后对其进行火用经济学分析,并指出了系统需要优化改进的组件。对设计条件下的单位热经济学成本构成计算,热力过程的成本形成和分布规律进行了深入的分析,揭示了能量损失具有不等价性。结果表明:该方法与传统分析方法相比,能够更加准确合理的评价机组的节能潜力,为其他大型火电机组及相关的复杂能量系统运行的经济性分析和优化改造提供了更加有效的方法。     

660 MW燃煤发电机组的碳捕集系统余热利用和集成系统性能评估

碳捕集与封存（CCS）技术能有效捕获燃煤电厂排放的CO₂但再生能耗大且效率低。为提高燃煤电厂能源利用效率,提出集成有机朗肯循环（ORC）与CCS的太阳能-燃煤发电系统,利用热力学、火用和经济性分析模型对集成系统进行参数敏感性分析。基于外部燃料火用矩阵模型,分析再沸器所需热量中CO₂压缩过程和太阳能集热器的热量占比及集成ORC系统对外部燃料火用贡献度的影响。研究表明：当热源比θ=0.4时的集成系统热经济性能最优且具有较合理的不可逆性;集成ORC系统后锅炉燃煤火用、一、二次再热燃煤火用对系统产品的贡献度均有所提高;随着θ增加,锅炉燃煤火用和一、二次再热燃煤火用对碳捕集系统产品的贡献度逐渐降低;压缩余热火用和太阳能火用的贡献度逐渐增加。     

Thermo-economic modeling of a solid oxide fuel cell/gas turbine power plant with semi-direct coupling and anode recycling

Power generation using gas turbine (GT) power plants operating on the Brayton cycle suffers from low efficiencies, resulting in poor fuel to power conversion. A solid oxide fuel cell (SOFC) is proposed for integration into a 10 MW gas turbine power plant, operating at 30% efficiency in order to improve system efficiencies and economics. The SOFC system is semi-directly coupled to the gas turbine power plant, with careful attention paid to minimize the disruption to the GT operation. A thermo-economic model is developed for the hybrid power plant, and predicts an optimized power output of 21.6 MW at 49.2% efficiency. The model also predicts a breakeven per-unit energy cost of USD 4.70 ¢/kWh for the hybrid system based on futuristic mass generation SOFC costs. Results show that SOFCs can be semi-directly integrated into existing GT power systems to improve their thermodynamic and economic performance.     

楼宇冷热电联供系统的热经济性分析

在对一实际楼宇冷热电联供系统热力学分析的基础上，对该系统作了热经济性分析，将作功能力法和热量法相结合，结合系统的实际经济数据。对该系统的成本进行分摊，得出了夏季变工况运行条件下冷、热、电三种产品的单位Yong成本和单位能成本，并对其进行了分析比较．结果表明：当系统保持足够的负荷率时，这种系统具有经济上的竞争力；而补燃措施会给系统的Yong效率和经济性带来很大的不利影响．     

Thermo-economic modeling of an indirectly coupled solid oxide fuel cell/gas turbine hybrid power plant

Power generation using gas turbine (GT) power plants operating on the Brayton cycle suffers from low efficiencies, resulting in poor fuel to power conversion. A solid oxide fuel cell (SOFC) is proposed for integration into a 10 MW gas turbine power plant, operating at 30% efficiency, in order to improve system efficiencies and economics. The SOFC system is indirectly coupled to the gas turbine power plant, paying careful attention to minimize the disruption to the GT operation. A thermo-economic model is developed for the hybrid power plant, and predicts an optimized power output of 20.6 MW at 49.9% efficiency. The model also predicts a break-even per-unit energy cost of USD 4.65 ¢ kWh⁻¹ for the hybrid system based on futuristic mass generation SOFC costs. This shows that SOFCs may be indirectly integrated into existing GT power systems to improve their thermodynamic and economic performance.     

Exergoeconomic analysis of a new integrated copper-chlorine cycle for hydrogen production

In this study, an exergoeconomic analysis is performed on an integrated four-step thermochemical copper-chlorine cycle developed at the Ontario Tech. University through exergy, cost, energy, and mass (EXCEM) method. A thermodynamic model is first constructed in Aspen-plus (a process simulation software) to simulate and investigate the integrated cycle through exergy and energy analyses. The capital costs, thermodynamic loss rates, and the ratio of the thermodynamic loss rate to the capital cost of various system's components are also determined. Moreover, the average unit cost of hydrogen is evaluated and the influence of several system's parameters on the unit cost of hydrogen is analyzed. The results show that the cost of hydrogen is strongly dependent on the production capacity of the plant. Based on the analysis, our system generates hydrogen at an average unit cost of 5.54 $/kg with a plant capacity of 1619.3 kg/h considering both internal (operating and maintenance costs, etc.) and external (costs of various inputs, etc.) parameters.     

基于结构理论的350MW超临界直接空冷机组的热经济学分析

应用结构理论建立了某超临界直接空冷机组的热经济学模型,通过量化各组件间的生产交互关系、计算各组件的单位成本,分析了系统生产成本的形成过程.简化合并直接空冷机组的凝汽组件,并近似计算其耗电量.根据该机组THA工况的计算结果,分析了影响组件产品单位成本的因素.结果表明:当消耗同一种燃料时,组件效率越低,其产品单位成本就越高;当消耗不同燃料时,要综合考虑燃料成本和效率对产品单位成本的影响,并指出7号低压加热器、给水泵、小汽轮机以及凝结水泵等组件的单位成本较大;直接空冷机组凝汽器的单位成本显著高于湿冷机组,应用结构理论能够准确评价空冷机组的生产性能.     

Study of MW-scale biogas-fed SOFC-WGS-TSA-PEMFC hybrid power technology as distributed energy system: Thermodynamic,exergetic and thermo-economic evaluation

Advanced biogas power generation technology has been attracting attentions, which contributes to the waste disposal and the mitigation of greenhouse gas emissions. This work proposes and models a novel biogas-fed hybrid power generation system consisting of solid oxide fuel cell, water gas shift reaction, thermal swing adsorption and proton exchange membrane fuel cell (SOFC-WGS-TSA-PEMFC). The thermodynamic, exergetic, and thermo-economic analyses of this hybrid system for power generation were conducted to comprehensively evaluate its performance. It was found that the novel biogas-fed hybrid system has a gross energy conversion efficiency of 68.63% and exergy efficiency of 65.36%, indicating high efficiency for this kind of hybrid power technology. The market sensitivity analysis showed that the hybrid system also has a low sensitivity to market price fluctuation. Under the current subsidy level for the distributed biogas power plant, the levelized cost of energy can be lowered to 0.02942 $/kWh for a 1 MW scale system. Accordingly, the payback period and annual return on investment can reach 1.4 year and about 20%, respectively. These results reveal that the proposed hybrid system is promising and economically feasible as a distributed power plant, especially for the small power scale (no more than 2 MW).     

Performance assessment and optimization of an integrated solid oxide fuel cell-gas turbine cogeneration system

The combined solid oxide fuel cells and gas turbine (SOFC/GT) system is known to be a potential alternative for distributed power generation. In this paper, a novel SOFC/GT based cogeneration system, which integrated a transcritical carbon dioxide cycle (TRCC) with a LNG cold energy utilization system is proposed. A mathematical (zero-dimensional) model is developed to analyze the co-generation system performance from the perspective of thermodynamic (energy and exergy) and economic costs. The main parameters of the system are chosen to analyze their effects on thermodynamic performance. The results show that the current system can achieve 64.40% thermal efficiency and 62.13% exergy efficiency under given conditions, and can further improve efficiency through parameter optimization. Finally, the multi-objective optimization program using NSGA-II (Non-dominated Sorting Genetic Algorithm II) is used to obtain the optimal value of the system design parameters. In the multi-objective analysis, the thermodynamic efficiency and economic cost of the system are considered as objective functions. The optimization results show that the final optimized design selected from the Pareto front can achieve 63.08% thermal efficiency and 61.10% exergy efficiency, respectively.     

Exergy and exergoeconomic analysis of a crude oil combined distillation unit

The combined distillation unit is the first plant in a crude oil refinery, in which several intermediate products, i.e. liquid petroleum gas (LPG), naphtha, jet fuel, kerosene, diesel fuel, gas oils and reduced crude, are obtained through atmospheric and vacuum distillation of the crude oil mixture. It is important to determine the critical points in the unit from the exergy view point and to properly allocate the total production cost to the different simultaneously produced streams, to determine the monetary flows all through the plant, and to state the relevance in economic terms of the exergy losses of each individual equipment item. The results of the exergy and exergoeconomic analyses are presented in this paper. The most important factor affecting the transformation, operation and production costs of the products is the cost of the crude oil raw material; utilities, salaries, maintenance and even capital investment costs are less important. Also the critical points of the plant are presented which provide the basis for the optimization of the unit showing additional opportunities for process integration.     

Exergoeconomic analysis of hydrogen production from biomass gasification

In this study, we investigate biomass-based hydrogen production through exergy and exergoeconomic analyses and evaluate all components and associated streams using an exergy, cost, energy and mass (EXCEM) method. Then, we define the hydrogen unit cost and examine how key system parameters affect the unit hydrogen cost. Also, we present a case study of the gasification process with a circulating fluidized bed gasifier (CFBG) for hydrogen production using the actual data taken from the literature. We first calculate energy and exergy values of all streams associated with the system, exergy efficiencies of all equipment, and determine the costs of equipment along with their thermodynamic loss rates and ratio of thermodynamic loss rate to capital cost. Furthermore, we evaluate the main system components, consisting of gasifier and PSA, from the exergoeconomic point of view. Moreover, we investigate the effects of various parameters on unit hydrogen cost, such as unit biomass and unit power costs and hydrogen content of the syngas before PSA equipment and PSA hydrogen recovery. The results show that the CFBG system, which has energy and exergy efficiencies of 55.11% and 35.74%, respectively, generates unit hydrogen costs between 5.37 $/kg and 1.59 $/kg, according to the internal and external parameters considered.