节能减排下热电联产燃机项目电价政策的思考

随着天然气价格上涨,燃机发电上网电价政策成为热电联产燃机项目生存的重要条件之一.通过理论分析和实证检验,就当前热电联产燃机发电上网的＂高电价＂对燃机项目运营的影响进行了探讨,结果表明：相对于热价,偏高的上网电价易导致电厂愿意多发电,少供热,结果降低了全厂的热效率,不利于全社会的节能降耗.     

日本火电机组热效率高的原因分析

日本的火力发电机组能源利用效率高,常规的燃煤发电的热效率达到了43％以上,燃气机组由于采用了联合循环系统,其热效率水平更高,达到了53％以上。其综合的热效率较我国的火力发电的热效率高很多,这与发电机组的设计制造水平有关,也与机组的运行工况有关。从日本的一次能源供给情况、发电用能源的结构状况、各种类型发电机组的负荷情况等分析其热效率高的原因,并对我国的电源结构及各种类型发电机组的负荷情况进行分析,提出应适当调整我国的电源结构、提高能源利用效率的相关建议。     

太阳能热发电用双层壁蓄热单元数值模拟

利用FLUENT软件中的凝固/熔化模型,对采用双层壁圆筒内填充相变材料(PCM)蓄热的太阳能热发电高温相变蓄热单元的蓄热过程进行了数值模拟研究,在保证蓄热量的前提下,得到了在第3类边界条件下不同管径蓄热单元内相变材料熔化过程中温度和液相率曲线及液相率的分布云图,并对结果进行了分析,掌握了太阳能热发电高温相变蓄热单元相变过程的规律,为太阳能热发电高温相变蓄热器的优化设计提供了重要参考价值和理论依据。     

Bewertungskriterien einer optimierten Energieversorgung regionaler Verbünde mit hohen Anteilen erneuerbarer Erzeugung

To determine an optimum economic solution for a renewable energy supply, an integral consideration of the system would be desirable. Because the difficulty of implementation increases with the number of stakeholders involved, locally optimized sub systems could accelerate the change in energy supply, albeit the global optimum might not be reached. An enhanced regional self-sufficiency could be a conceivable measure to increase public acceptance for interventions in the energy supply system. In this paper different ratios for quantification and illustration of the improvement of an optimized energy supply are defined. The effectiveness of demand side management, flexibly operated cogeneration units and energy storages are examined. The results are compared with those of a systematic throttling of producers during peak times. The calculations are performed within the Regenerative Modellregion Harz project, one of six model regions that are supported by the Federal Ministry of Economics and Technology and the Federal Ministry for Environment, Nature Conservation and Nuclear Safety within the E-Energy-initiative. The potential for increasing the internal consumption and the ratio of self-supply of the listed residual load smoothing methods can be determined. The reduction of maximum imports and exports by demand side management and flexibly operated cogeneration units prove to be comparatively small. A greater effect on the level of residual loads can be achieved by the use of storage power plants and especially power-to-gas because of the technology??s high storage capacity. A strong decrease of maximum exports can be realized by systematic reduction of production during peak times. The required grid capacities can almost be cut in half by using 99 instead of 100 percent of the power generation potentials.     

热泵循环技术在热电厂的应用

介绍了热泵技术的原理,并结合某发电厂应用实例,说明了在电厂中可以采用热泵技术,循环水不再全部依靠冷却塔降温,而是部分作为各级热泵的低温热源,提高热电厂额定供热能力,减少了汽轮机的抽汽量,增加汽轮机的发电能力,提高系统整体能效。经过实际运行,各项指标达到了设计要求。热泵循环技术在热电厂中应用前景良好,具有推广价值。     

Abschätzung des Potenzials der Schweizer Speicherseen zur Lastdeckung bei Importrestriktionen

Switzerland possesses with its hydro reservoirs a considerable amount of energy storage capacity. One would therefore assume that the country is well protected against power shortage situations in continental Europe. In the last two winters, however, authorities and system operators warned of possible threats to security of supply. Power producers were accused in the media of emptying the lakes too early for the sake of short-term profits. Politicians suggested to use the reservoir lakes as strategic reserves for the potential case of import restrictions. The current piece of work simulates the aggregated storage production in Switzerland based on publicly available data under various assumptions on the availability of power plants and imports. It comes to the conclusion that, over the last few years, the energy reserves in Swiss reservoir lakes would have been sufficient to cover domestic electricity demand in the absence of imports for at least one month. However, considerable changes in the use of hydro storage facilities would be necessary in future to ensure the same level of protection when nuclear production is phased out. The economic loss due to such an intervention may quickly rise to several dozen million Swiss francs.     

蓄能调温负荷与光伏的智能化互动运行策略

为了充分利用蓄能调温负荷的调节资源,节约调温负荷的用电成本,并有效消纳光伏电量,提出了"光伏+调温负荷"的智能化互动运行策略。首先,建立了基于户型参数和天气信息的房屋冷、热需求模型;其次,以运行成本最小为目标,结合光伏出力和用冷、用热需求,在优先使用谷电电量的原则下,提出蓄能负荷与光伏供用电互动逻辑和运行策略;第三,以全年天气数据为驱动,按互动逻辑关系进行了全年运行累积计算的年运行成本分析。结果表明,互动运行模式相比于光伏与蓄能调温负荷独立模式的运行成本有很大降幅,"光伏+调温负荷"策略有效解决了光伏消纳和调温负荷电费的问题。这不仅有利于减少环境污染,还能够实现政府与用户的双赢。     

河北保定高速某服务区蓄联热泵清洁供暖技术改造研究[JP]

为了提升空气源热泵低温环境中的热效率,解决热泵冬季易结霜、故障率高等问题,提出一种利用相变蓄能装置将空气源热泵和水源热泵组合的蓄联热泵技术。以河北保定高速某服务区蓄联热泵的改造工程为例,设计了蓄联热泵系统改造方案,并将蓄联热泵联合供暖系统的实际运行数据与位于同一地区、相似建筑中使用单一热源供暖的空气源热泵系统运行数据进行对比,考察供水温度、室内温度、单位供暖面积的耗电量和COP值等因素的变化情况。研究结果表明,在相同室外气温、相同单位面积供暖热负荷的条件下,蓄联热泵供暖效果更稳定,室内温度更高,蓄联热泵每平方米耗能相比空气源热泵低15.5%,综合COP提高了20.68%,静态投资回收期为11.89年。蓄联热泵清洁供暖技术具有一定的可靠性和经济性,适用于低温持续时间较长的偏远山区等寒冷地区,研究结果对蓄联热泵的推广具有重要的借鉴意义与应用价值。     

基于混合储能的直流微网母线电压控制策略

为了平抑风力发电接入直流微电网的功率波动问题,满足负荷持续高质量供电需求,对由锂电池和超级电容器组成的混合储能系统进行了研究。以超级电容电压和锂电池荷电状态为约束条件,将储能系统平衡所需的功率差分为低频与高频部分;锂电池用于吸收和释放低频部分,超级电容用于吸收和释放高频部分,使风机整流器工作在恒压状态,采用电压外环、电流内环双闭环控制,以直流母线的电压稳定为目标,维持系统功率平衡。仿真结果表明,所提混合储能系统控制策略具有较快的动态响应速度和较好的控制性能,可很好地满足负载功率需求,稳定直流母线电压。研究结果可为分析规模化新能源接入直流微网系统的稳定问题提供参考。     

太阳能热动力发电系统中高温热管式吸热/蓄热器技术研究

介绍了近年来热管式吸热/蓄热器的研制情况,分析了热管式吸热/蓄热器的结构原理,认为热管式吸热器不仅能改善温度均匀性,而且能有效利用相变材料,这使得吸热器的热性能和质量得到明显改善,可成为新一代太阳能热动力系统重点研制的对象,并指明了研制热管式吸热/蓄热器需解决的几个关键问题。     

Selecting make-to-stock and postponement policies for different products in a chemical plant: A case study using discrete event simulation

We present a guideline for selecting the inventory management policy for a specialty chemical plant that produces products with limited shelf life, by producing multiple grades of bulk chemical and packaging them into a large variety of bottles. The policy for each product was selected based on a cost-benefit analysis, using the multiple objectives of maximizing the on time order fulfillment, minimizing the production (cleaning and shelf life expiration) and inventory costs. To generate realistic cost estimates, we developed a discrete event simulation model that included demand variability, planning and scheduling policies, and operational details. We evaluated three different policies: make-to-stock (MTS), postponement, and combined MTS/postponement. We also evaluated different storage media and optimized the number of storage units for products selected for postponement. A combined MTS/postponement policy, in which postponement is applied to products with low to medium demand and high expiration provided lowest costs without significantly impacting the customer on time order fulfillment. For all other products, a MTS policy is applied to maximize order fulfillment on time, reduce cleaning costs and to reduce number of storage units.     

Operating Strategies for Battery Storage Systems in Low-Voltage Grids to Limit the Feed-In Power of Solar Power Systems Using Fuzzy Control

Germany’s energy turnaround is leading to an increasing integration of photovoltaics (PVs) throughout its distribution grid. To ensure safe grid operation in times of high solar radiation, PV plants must either be throttled back to comply with the feed-in limitation or store a portion of their excess electricity in batteries. This paper presents a grid-optimized operating strategy for PV storage systems based on a Fuzzy Logic Controller that reduces peak feed-in and thus also PV curtailment losses. The Fuzzy Logic Controller uses data on PV power surplus and battery charge level as input variables. To obtain good results, the set of numerical parameters of the membership functions is enhanced by evolutionary programming.The energetic assessment shows that even small electrical storage capacities (<<5?kWh) reduce curtailment losses considerably when using the grid-optimized operating strategy. The economic assessment shows that, in 2016, investments in PV storage systems with large PV plants and small batteries have small (positive) Internal Rates of Return. The system efficiency of the battery storage has a small impact on the profitability of PV storage systems, whereas the cycle stability and the electricity purchase price have a large impact. Moreover, there is an economic benefit for plant operators to switch from the simple to the grid-optimized operating strategy. Solar forecast inaccuracies and variations in load and generation profiles have a negligible impact on the performance of the control algorithm.     

关停小火电机组对“十一五”规划电网的影响分析

大多数小火电机组处在电网的负荷中心,对电网起着提供灵活有功和无功电源的作用。通过分析可知,按照要求关停的小火电规模,对国家电网公司经营范围内的"十一五"电网规划总体影响不大,对局部电网供电能力、网架结构、动态无功和网损将产生一定影响,需要增加部分配套的电网建设项目和适当调整原规划中某些电网项目的建设时序,以满足"上大压小"方案实施后安全、可靠供电的需要。     

Impact of Modeling Approaches on Dispatch Optimization of Combined Cycle Gas Turbines

Due to the age structure of the German generation system and the nuclear phase out, a significant amount of older power plants will be substituted during the coming years by newly built generation units. Such projects are frequently realized as combined gas and steam turbines, so-called Combined Cycle Power Plants or Combined Cycle Gas Turbines (CCGT). These power plants, mostly fired by natural gas, possess high efficiency factors combined with low specific CO₂-emissions compared to other conventional power plants, e.g. fired by coal and moreover provide a high operational flexibility. As they represent a combination of several thermal processes, their generation planning and optimized dispatch are more demanding than those of existing steam or gas turbines. Therefore, a new formulation of the unit commitment problem is required, including all relevant technical and economic restrictions for scheduling CCGT. In this paper, the relevant characteristics of the different types of CCGT are analyzed. This especially includes part load efficiency and the permitted modes of operation. For modeling of these characteristics and for optimizing the CCGT dispatch, a decomposition approach as well as a linearized closed-loop formulation is introduced. In the decomposition the optimization problem is split into sub problems, which can be solved with specialized algorithms. As the recombination of these sub problems may result in a limitation of the overall solution quality, the closed-loop approach considers the entire problem, but has to linearize the formulation to ensure solvability. By applying both methods on an exemplary case the advantages and shortcomings of both approaches can be analyzed in detail. This comprises model accuracy, overall solution quality and a detailed schedule analysis and comparison. The paper??s results will also show the deviations caused by the different modeling approaches. Finally, the results show the added value of the adequate modeling of combined cycle power plants towards gas or steam turbines.     

一种清洁能源与市政热网互补的供热系统设计及模拟研究

北方地区的建筑供暖需求随着城市建筑面积的迅速增长而不断增加,而城市热网改扩建缓慢,供热能力不足,距城区较远的新建及改扩建小区的供暖需求面临挑战,并且供暖带来的高能耗及环境污染问题日益严峻。针对此类问题,提出了将太阳能、空气能与传统市政热网相结合、互为补充的清洁能源与市政热网多能互补的集中供热系统,利用TRNSYS软件建立系统模型,设计系统5种不同的运行模式及相应的运行控制策略,并以石家庄市某新建小区为例进行分析。模拟运行结果表明,在整个供暖季中,运行时间较长的是太阳能辅助双热源(水源)热泵供热模式和双热源(空气源)热泵供热模式,清洁能源的供热比例为82.15%,热泵机组效率高,平均COP为4.06,远高于常规的热泵机组。研究结果可为周边供热能力不足的新建及改扩建小区选择供热系统提供参考。     

促进关停小火电机组的经济政策浅析

从市场角度出发,以限制小火电机组的生存空间为目的,落实国家产业政策,促进关停小火电机组政策的顺利实施,提出应采取的措施包括按发电成本重新核定小火电机组上网电价、根据情况为小火电机组的技术改造提供资金支持、通过"以大代小"制定电量置换政策、出台资源高消耗税和环保税,以提高小火电机组的发电成本而迫使其关停或进行技改等。     

蒸发器积霜对冷库热工状况的影响

为了探讨冷库蒸发器积霜对冷库热工状况的影响,为冷库及时化霜和无霜运行提供科学依据,试验选用10t3HP的双温双控冷库为研究对象,动态监测了蒸发器积霜前和积霜后两段时间内库温、霜温、蒸发器进风口与出风口温差、冷库耗电量,绘制了蒸发器外表面的三维温度场。试验结果表明:蒸发器积霜前,库温周期变化较为稳定;积霜后,冷库运行周期由3个阶段变为风机运行和制冷2个阶段且库温最低温度逐渐升高,达不到设定下限,周期变化幅度减小,用时缩短。积霜后的霜温周期最低值达到霜温设定下限,冷库不能在正常设定的范围内运行,蒸发器的制冷效率明显下降。蒸发器积霜使进风口与出风口温差减小;冷库运行12h的耗电量增加147.06%。积霜后蒸发器外表面三维温度场显著不同,各点温度都有所下降,偏离设计的最低温度。试验表明,冷库运行过程中不积霜运行是冷库节能安全运行的重要因素。     

抽油机双功率电机在安塞油田应用的节能分析

在油田企业,机械采油电力驱动装备俱为电机,约占总耗电量的80％。在实际生产中,很多抽油机电机处于轻载、低效、高耗的运行状态,电能浪费严重。因此,电机节能降耗是解决油田节电降耗、降低开采成本的主要方向。通过分析抽油机光杆功率与电机额定功率的理论关系,结合2011年安塞油田引进安装双功率电机的现场应用效果,阐述其工作原理和技术指标,并根据现场监测得到电能参数进行客观、准确的分析评价。     

石家庄市某住宅小区中水源热泵供热系统应用与分析

中水源热泵机组是利用中水作为热源的高效节能技术。通过石家庄市某住宅小区的工程实例,分析了中水源热泵机组的运行情况,机组的经济效益、节能效益和环境效益,结果表明,在石家庄地区应用中水源热泵供热系统不仅能满足用户的供暖需求,而且有较大的节能减排效果。