Modeling and design of a 25 MW osmotic power plant (PRO) on Bahmanshir River of Iran

Osmotic energy is one of the renewable energies. This osmotic energy source is easily obtainable all over the world where river water flows into the ocean or sea. In this article, Bahmanshir River in Iran which falls into the Persian Gulf was considered as selected place for modeling and design of 25 MW osmotic power plant in PRO method. Results indicates that for a 15 year return on investment, annual increase in purchase price of electricity 10% and interest rate 6%, sale price of electricity should be 0.4117 €/KWh which is highly expensive compared to state's suggested price of electricity from renewable source (i.e. 0.09 €/KWh).In order to balance purchase and sale price of electricity, unit price of intake and outfall, unit price of micro-filtration and interest rate should be reduced 9.1%, 15% and 25% respectively and Δλ should be increase 4.3%.     

A closed loop supply chain under retail price and product quality dependent demand

The importance of remanufacturing of used products, maintaining the same quality as new ones has been widely recognized in practice. In this paper, we address a closed loop supply chain where the manufacturer manufactures a product with a decent quality acceptable to customers, and sells it through a retailer in the market. A third party collects the used products from consumers and sends to the manufacturer. The manufacturer re-manufactures the used product and the quality of remanufactured product is the same as that of the manufactured one. For such a closed loop supply chain, we construct five different scenarios – centralized, decentralized or Nash game and three different Stackelberg games, led by the manufacturer, retailer and third party respectively. We compare the optimal results to find out the best decentralized scenario out of the four mentioned. A numerical example is taken to study the impacts of product quality on demand as well as optimal decisions and investigate sensitivity of some key model-parameters.     

Interactions between hybrid nanosized particles and convection melting inside an enclosure with partially active walls: 2D lattice Boltzmann-based numerical investigation

The ice melting is investigated inside a square cavity with two isothermally partially active walls. The concept of dispersing hybrid alumina–Cu nanoparticles and hybrid silica–multiwalled carbon nanotubes (MWCNTs) nanoparticles is recommended for thermal performance enhancement in this thermal energy storage (TES) system. The two-dimensional explicit lattice Boltzmann convection melting scheme in the single-phase model is applied to account for the natural convection flow induced in the melt region and evolution of the solid–liquid interface. The complete melting time for the pure phase change material (PCM) using case (II) is 33.3% lower compared with other cases. If the price of hybrid Al₂O₃–Cu nanoparticles and heat storage capacity is important, the full melt time diminishes by 16.6% with a volume fraction of 0.01 in case (II). Once hybrid silica–MWCNT nanoparticles with a volume fraction of 0.01 are utilized inside case (II), the lowest charging time is achieved. The complete melting time abates by 23.66% in contrast to the pure PCM melting. The use of single/hybrid nanoparticles to enhance the PCM melting is not necessarily economical as efficient positions of active parts could further lessen the charging time. The efficiency of hybrid nanoparticles is linked to the type and weight proportions of nanoparticles, and positions of thermally active parts.     

我国两部制电价制度对天然气发电企业盈利能力的影响

上海、浙江和江苏等地陆续出台了两部制电价制度,以期解决天然气发电(以下简称气电)企业成本高、经营困难等问题。为了研究该电价制度对气电企业盈利能力的影响,在对比分析上述三地电价政策和实施效果的基础上,基于不同类型机组的三大经营指标(项目财务内部收益率、经济净现值、动态投资回收期),采用项目经济性分析模型探究了不同类型燃气电厂的经济性。研究结果表明:①现行两部制电价与单一制电价相比,电价水平小幅度下降,给企业经营带来了一定的冲击,但从长远看,则有利于形成可持续的发展机制;②两部制电价是各地政府经过充分调研和测算后根据该区具体情况制定的,在该政策下多数企业处于盈亏平衡点附近,综合条件优、管理水平高的企业能取得一定的盈利,反之则亏损;③当电量电价一定且大于盈亏平衡点时,企业效益随年利用小时数的增加而提升,反之则随年利用小时数的增加而降低。结论认为:①两部制电价能起到促进企业管理和技术水平提升,引导和鼓励电力投资的作用,符合我国电力体制改革的方向;②政策制定时应针对不同时期建成的项目加以区别对待,实现上网电价、天然气价格和供热蒸气价格的"三个联动";③应建立大数据平台,实行气网、电网联合调度;④发电企业应创新管理,降低电厂建设及维护成本,提升机组效率,降低气耗。     

基于PSCAD/EMTDC软件的高压直流输电仿真教学研究

针对“高压直流输电”课程教学过程中,高压直流系统控制原理复杂抽象,直观上难以理解的特点,本文通过运用PSCAD/EMTDC仿真软件,基于CIGRE HVDC标准测试模型,对高压直流输电系统在整流侧和逆变侧交流系统分别发生故障时的运行特性进行仿真测试。教学实践表明,PSCAD/EMTDC软件的应用加强了学生对理论知识的理解,激发和培养了学生的学习兴趣和动手实践能力,有效地提升了教学效果。     

俄罗斯天然气在东北地区的利用发展分析

中俄东线天然气即将引入中国,将对东北地区的天然气利用项目产生有力的推动作用,同时也将面临各种问题。为建立长期可持续发展资源供应体系,结合能源供需实际,讨论了俄气到来后,东北地区天然气未来的发展方向,并分析了存在的主要问题:①天然气自产不足,域外依存度高;②地域特点决定替代能源可有多种选择;③调峰困难且富余天然气难以处理;④天然气替代经济性差,价高难以承受。并针对矛盾点进行了总结,指出来源多元化和资源多样化才能可持续发展。明确东北地区宜以天然气作为过渡能源,并提出了适宜地区经济发展的天然气利用建议。     

Shale gas pad development planning under price uncertainty

In this article, we study shale gas pad development under natural gas price uncertainty. We optimize the sequence of operations, gas curtailment, and storage on a single pad to maximize the net present value. The optimization problem is formulated as an mixed-integer linear programming model, which is similar to the one proposed by Ondeck et al. We investigate how natural gas price uncertainty affects the operation strategy in the pad development. Both two-stage and multistage stochastic programming are used as the mathematical framework to hedge against uncertainty. Our case study shows that there is value of using stochastic programming when the price variance is high. However, when the variance of the price is low, solving the stochastic programming problems does not create additional value compared with solving the deterministic problem.     

燃煤机组湿法脱硫经济性分析

以2×300 MW燃煤机组为例,在征收SO2排污费及脱硫电价补贴情况下,通过对WFGD系统经济效益影响因素的盈亏平衡点和敏感性程度进行分析,得到运行时间、上网电价、石灰石粉价格、脱硫电价补贴的盈亏平衡点分别为:2064 h、0.862元/kWh、1266元/t、0.0072元/kWh,其中脱硫电价补贴最为敏感。     

国际市场油价走势分析和下半年预测

由于供需基本面宽松而地缘政治局势紧张,2014年上半年布伦特油价因而继续高居于每桶108美元左右。下半年需求季节性增加,而供应增长落后于预期,可能使基本面趋紧,油价低于上半年的机会减小。     

2013年国际油价走势回顾与2014年预测

回顾了2013年国际油价的走势,分析了影响2014年国际油价的主要因素,预测了2014年国际油价的可能变化趋势。