不同运行调度模式下微网经济运行对比分析

为了对比分析不同运行调度模式对微网经济运行的影响,在考虑微源同时提供有功和无功功率的基础上,提出了计及制热收益的热电联产型微网系统经济运行优化模型.以一个包含风、光、储、微型燃气轮机、燃料电池以及热电负荷的具体微网为例,提出了不同运行调度模式下的经济调度策略,运用改进遗传算法优化了考虑实时电价的并网运行方式下各微源的有功和无功出力,并对比分析了微网与外网交互功率的约束以及不同运行调度模式对经济调度的影响.仿真结果表明微网可与外网自由双向交换功率的模式更具有经济优势,验证了所提模型、策略和算法的有效性.     

小型发电机组矢量保护的研究

热电联供系统正在我国兴起,关键设备和并网标准依旧参照国外标准,所以这些机组在国内使用中常常遇到一些问题,如发电机组经常性的发生矢量保护。针对在使用国外机组时遇到的某些问题,对小型发电机组矢量保护的原理和误动作原因进行了阐述。矢量保护主要用于对机组并网进行保护,避免机组孤岛运行。由于发电机继电器整定值偏小,对电网波形要求过严导致误动作,在增大设定值后解决该问题。希望我国尽快出台小型发电机组并网标准,以便更好地推广热电联供项目。     

System design and process layout for a SOFC micro-CHP unit with reduced operating temperatures

Anode-supported cells (ASC) are considered as a promising SOFC technology for achieving higher power densities at significantly reduced operating temperatures. Thereby it is commonly expected to enhance both the profitability and durability of fuel cell systems in real world applications. In the collaborative project LOTUS, a micro-CHP system prototype will be developed and tested based on a novel ASC technology with an operating temperature of 650 °C. Extended system design considerations are required in the first place to establish a basis for the system development process. This paper reveals the initial system design investigations for the LOTUS system concept, thus addressing modeling approach and concluding design decisions.     

Thermochemical model and experimental validation of a tubular SOFC cell comprised in a 1 kWel stack designed for μCHP applications

Being aware of the needs for clean highly efficient micro combined heat and power (μCHP) systems for single and multifamily households, the Italian Ministry of Industry launched in 2009 the EFESO Project aiming to develop and operate four SOFC prototypes. An imperative part of the project foresaw computational modeling to optimize operating conditions of the power modules and pinpoint potential drawbacks in its design. This article deals with a 3-dimensional thermochemical model of a single SOFC tubular geometry cell comprised in a 1kW_el stack operating under similar conditions to the characterized power module. An analysis is presented on the effects of current density distribution, temperature distribution in the cell and pressure drop in the air and fuel channels, being these the most critical variables when operating the SOFC-powered μCHP system. This model will serve as a platform to generate a model of the whole stack which will be further validated by means of experimental activities.     

垃圾焚烧电厂热电联产的经济性分析

合理利用垃圾资源进行热电联产,是节能减排、改善环境的有力措施。以某2×750 t·d^-1垃圾焚烧电厂为例,通过模型研究发现热电联产可以减少垃圾焚烧电厂的冷源损失,提高全厂热效率;利用一抽蒸汽进行热电联产可实现蒸汽品质的梯级利用,获得较高的经济效益;供热量为30 t·h^-1,垃圾热值由4185.9 kJ·kg^-1增加至8371.7 kJ·kg^-1时,发电量越多,供热能力越强,年热电联产经济效益由7822.76万元增加到14641.07万元;垃圾热值为8371.7 kJ·kg^-1,供热量从10 t·h^-1增加到60 t·h^-1时,垃圾焚烧电厂热效率从28.96%增加到48.50%,年经济效益从13602.74万元增加到15455.66万元。当该地区垃圾热值较高并具备供热条件时,实现垃圾热电联产具有较高的收益。     

不同环境温度与负荷条件下燃气轮机联合循环热电联产特性分析

为研究环境温度、热电负荷条件对联合循环热电联产全工况性能的影响,采用模块化建模方法对系统各部件建模,利用各部件参数的相互关系将各模型耦合得到联合循环热电联产模型,通过对比分析各环境温度下的机组特性得出结论:满负荷时,随环境温度的变化联合循环热效率存在最佳值,主要与凝汽器压力变化规律有关,凝汽器压力在环境温度Ta=8℃时变化规律发生转变,联合循环效率在该温度下出现最佳值;变负荷运行时,底循环性能在高、中间和低负荷区域内的最佳环境温度不同;供热工况下,分析了热电联产机组不同评价指标下的最优供热方式,其中以经济效率作为热电联产评价指标时,在任何热负荷下都建议高电负荷运行。     

12MW生物质直燃发电的热电联产系统节能经济性分析

以山东阳信市某企业生物质直燃发电的热电联产系统为研究对象,以其热、电负荷计算为基础,进行了主要设备的选型匹配。同时从标准煤耗量、年均总热效率和成本节约三个方面对系统进行节能经济性分析,指出了热电厂梯级利用能量的意义。分析结果表明：实施热电联产后系统年均总热效率达到60.9%,较中小型纯凝机组的提高约25.9%;在企业年生产总量不变的条件下,年节约标准煤约35352t,极大地节约了生产成本,具有可观的经济效益。     

Energy efficiency analysis and impact evaluation of the application of thermoelectric power cycle to today’s CHP systems

High efficiency thermoelectric generators (TEG) can recover waste heat from both industrial and private sectors. Thus, the development and deployment of TEG may represent one of the main drives for technological change and fuel substitution. This paper will present an analysis of system efficiency related to the integration of TEG into thermal energy systems, especially Combined Heat and Power production (CHP). Representative implementations of installing TEG in CHP plants to utilize waste heat, wherein electricity can be generated in situ as a by-product, will be described to show advantageous configurations for combustion systems. The feasible deployment of TEG in various CHP plants will be examined in terms of heat source temperature range, influences on CHP power specification and thermal environment, as well as potential benefits. The overall conversion efficiency improvements and economic benefits, together with the environmental impact of this deployment, will then be estimated. By using the Danish thermal energy system as a paradigm, this paper will consider the TEG application to district heating systems and power plants through the EnergyPLAN model, which has been created to design suitable energy strategies for the integration of electricity production into the overall energy system.     

Economic analysis of a combined heat and power molten carbonate fuel cell system

Fuel cells can be attractive for use as stationary combined heat and power (CHP) systems. Molten carbonate fuel cell (MCFC) power plants are prime candidates for the utilization of fossil based fuels to generate high efficiency ultra clean power. However, fuel cells are considerably more expensive than comparable conventional technologies and therefore a careful analysis of the economics must be taken. This work presents analysis on the feasibility of installing both a FuelCell Energy DFC^® 1500MA and 300MA system for use at Adams Thermal Systems, a manufacturing facility in the U.S. Midwest. The paper examined thoroughly the economics driving the appropriateness of this measure. In addition, a parametric study was conducted to determine scenarios including variation in electric and natural gas rates along with reduced installation costs.     

Internalisation of external cost in the power generation sector: Analysis with Global Multi-regional MARKAL model

The Global MARKAL-Model (GMM), a multi-regional “bottom-up” partial equilibrium model of the global energy system with endogenous technological learning, is used to address impacts of internalisation of external costs from power production. This modelling approach imposes additional charges on electricity generation, which reflect the costs of environmental and health damages from local pollutants (SO₂, NO_x) and climate change, wastes, occupational health, risk of accidents, noise and other burdens. Technologies allowing abatement of pollutants emitted from power plants are rapidly introduced into the energy system, for example, desulphurisation, NO_x removal, and CO₂ scrubbers. The modelling results indicate substantial changes in the electricity production system in favour of natural gas combined cycle, nuclear power and renewables induced by internalisation of external costs and also efficiency loss due to the use of scrubbers. Structural changes and fuel switching in the electricity sector result in significant reduction of emissions of both local pollution and CO₂ over the modelled time period. Strong decarbonisation impact of internalising local externalities suggests that ancillary benefits can be expected from policies directly addressing other issues then CO₂ mitigation. Finally, the detailed analysis of the total generation cost of different technologies points out that inclusion of external cost in the price of electricity increases competitiveness of non-fossil generation sources and fossil power plants with emission control.