燃气-蒸汽联合循环热电冷联产系统优化运行

以系统的运行费用最低为目标，考虑系统全年的热电冷负荷需求和运行策略，建立了包括蓄能器的燃气-蒸汽联合循环热电冷联产系统优化运行的模型，最后以某区域为例，利用序列二次规划，验证了方法的有效性。     

意大利热电联产现状:能源政策、法规及市场自由化的影响

热电联产在意大利的应用比较普遍，但中小型热电机组的发展则比较缓慢。介绍了意大利的能源政策、法规及市场自由化对热电联产的影响，还介绍了意大利环境方面法规，意大利在热电(冷)联产方面的激励措施等。     

关于国产大型热电两用机组某些问题的探讨

为了大力推进节能减排工作,近来我国启动了"十大重点节能工程",其中区域热电联产工程进展迅速。国家大力倡导优选大型采暖、发电两用机组,三北地区有条件集中供热的大中城镇都在筹建或建设中,某些不采暖地区也将纯发电大型机组改造成热电联产机组。本文探讨对优先选用300MW及以上大型热电联产机组是有条件的,不宜过分强调;在大型火电机组再热器前(后)打孔抽汽改造,供热参数不匹配,不宜大力推广,这些机组改造仅做过渡措施,应积极开发新型大型高效热电联产机组。     

Biomass fired small-scale CHP in Sweden and the Baltic States: a case study on the potential of clustered dwellings

Sweden as well as the three Baltic states has an abundant supply of biomass, mostly wood waste. Much of it goes into district heating (DH), which has expanded continuously since the first system started 50 years ago. DH now accounts for 43% of the heating consumption and a further expansion is possible in many directions. Firstly existing DH systems can be enlarged, secondly DH can be upgraded to combined heat and power (CHP) to a much larger extent, thirdly new DH (and CHP) systems can be implemented in many smaller places down to 1000 inhabitants or less. The last alternative, biomass and especially pellets fired small-scale cogeneration in combination with local heating networks, is the topic for this paper. It presents a method to estimate the potential for small-scale DH and CHP and results from a “test” area in southeast Sweden. The method estimates local heat demand using databases with individual and statistical property data. It identifies areas with clusters of buildings where the heat demand is enough to implement decentralized small DH networks if possible in combination with small-scale CHP. In the event for Swedish circumstances very sparsely populated test area of 36×48 km² with around 8000 inhabitants, the total heat consumption in residential buildings is estimated to 84 GW h. When we have identified the areas with clusters of buildings, we have set the minimum heat consumption in such an area to 500 MW h. The area size is varied in 250 m steps from 250×250 m² to 1000×1000 m². For the four area sizes, the method then identifies and locates 30, 38, 38,30, respectively, clustered areas with a potential for small-scale DH and CHP worth investing closer.     

Transposition of the EU cogeneration directive: A vision for Portugal

The potential for new, small-scale and micro-cogeneration installations in Portugal is very considerable due to the number of potential host buildings. In this work, we discuss the legal framework of the Portuguese energy market, and some modifications to accommodate the Directive, 2004/8/EC are stressed. A practical case of cogeneration is also presented, showing the application of the Annex III (b) and (c) of the Cogeneration Directive. The practical case presented shows that micro CHP can be considered highly efficient, with parameters calculated with the Directive rules. Two main improvements in Portugal's energy policy are important: improvement on the permission to access grid system and improvement on support mechanisms indexing it to PES. The Cogeneration Directive transposition is an excellent opportunity to induce a less restrictive framework for the installation of new cogeneration systems, reducing the technological barriers, namely allowing medium-voltage connection with the grid, and improving the revenues provided from these small cogeneration systems. These modifications can improve significantly the number of potential hosts for small-scale cogeneration systems.     

Structure optimization of energy supply systems in tertiary sector buildings

Trigeneration systems, also known as Combined Heat, Cooling and Power (CHCP) systems, are interesting alternatives to supply different energy services in urban districts and in large buildings, particularly in warm areas such as Mediterranean countries. These systems can provide substantial benefits from economic, energetic, and environmental viewpoints, since the cogenerated heat can be used for heating in winter as well as cooling in summer with an absorption refrigerator. This paper develops an optimization model using Mixed Integer Linear Programming (MILP) to determine the type, number and capacity of equipment in CHCP systems installed in the tertiary sector as well as to establish the optimal operation mode for the different plant components on an hour-by-hour basis throughout the year. The objective function to be minimized is the annual total cost. The optimization model considers the legal constraints imposed to feed the surplus autogenerated electricity into the grid at a regulated feed-in tariff. The optimization model is applied to design a system providing energy services for a hospital located in the city of Zaragoza (Spain). The effects of the financial market conditions and energy prices in the optimal structure of the system are analyzed.     

2011年国际供电会议系列报道:分布式能源发展与用户侧电能的高效利用

对第21届国际供电会议的分布式能源(DER)与高效用能专题进行了梳理,围绕分布式电源(DG)/DER规划及研究、含DG/DER的配电网控制、用户侧发展及DG/DER技术4个方向详细归纳并介绍了世界范围内在该领域研究工作的重点、难点与进展情况。所述内容希望能够开拓中国学者在相关研究领域的视野,加深对当前配电网所面临的问题、机遇与挑战的理解,并最终推动国内智能配电网相关技术的研究、开发与工程应用。     

Quinic acid esters and sesquiterpenes from Sonchus arvensis

A phytochemical study on the whole plant of Sonchus arvensis and its antioxidant activity has been carried out. Three quinic acid derivatives (1–3), the rarely naturally occurring (p-hydroxyphenylacetyl) quinic acids, and two eudesmanolides (4 and 5) were newly found. Four known eudesmanolides (6–9) were isolated from the plant for the first time. Their structures were characterized by HRESIMS, IR, UV, 1D NMR, and 2D NMR. 1,1-Diphenyl-2-picrylhydrazyl (DPPH·)-scavenging activity was evaluated for each of the above 9 compounds (1–9) in comparison to standard antioxidants (caffeic acid and ascorbic acid). However, none proved to have a positive activity. The absence of antioxidant activity could be caused by the absence of ortho or para-diphenolic groups in all detected compounds, that are responsible of the activity against free radicals by an electron transfer reaction.     

Application of an empirical model in CFD simulations to predict the local high temperature corrosion potential in biomass fired boilers

To gain reliable data for the development of an empirical model for the prediction of the local high temperature corrosion potential in biomass fired boilers, online corrosion probe measurements have been carried out. The measurements have been performed in a specially designed fixed bed/drop tube reactor in order to simulate a superheater boiler tube under well-controlled conditions. The investigated boiler steel 13CrMo4-5 is commonly used as steel for superheater tube bundles in biomass fired boilers. Within the test runs the flue gas temperature at the corrosion probe has been varied between 625 °C and 880 °C, while the steel temperature has been varied between 450 °C and 550 °C to simulate typical current and future live steam temperatures of biomass fired steam boilers. To investigate the dependence on the flue gas velocity, variations from 2 m·s⁻¹ to 8 m·s⁻¹ have been considered. The empirical model developed fits the measured data sufficiently well. Therefore, the model has been applied within a Computational Fluid Dynamics (CFD) simulation of flue gas flow and heat transfer to estimate the local corrosion potential of a wood chips fired 38 MW steam boiler. Additionally to the actual state analysis two further simulations have been carried out to investigate the influence of enhanced steam temperatures and a change of the flow direction of the final superheater tube bundle from parallel to counter-flow on the local corrosion potential.     

Development of an experimental test rig for cogeneration based on a Stirling engine and a biofuel burner

A system consisting of a last-generation Stirling engine (SE) and a fuel burner for distributed power generation has been developed and experimentally investigated. The heat generated by the combustion of two liquid fuels, a standard Diesel fuel and a rapeseed oil, is used as a heat source for the SE, that converts part of the thermal energy into mechanical and then electric energy. The hot head of the SE is kept in direct contact with the flame generated by the burner. The burner operating parameters, designed for Diesel fuel, were changed to make it possible to burn vegetable oils, not suitable for internal combustion engines. The possibility of adopting different configurations of the combustion chamber was taken into account to increase the system efficiency. The preliminary configurations adopted allowed to operate this integrated system, obtaining an electric power up to 4.4 kW_el with a net efficiency of 11.6%.