Wind power forecasting uncertainty and unit commitment

In this paper, we investigate the representation of wind power forecasting (WPF) uncertainty in the unit commitment (UC) problem. While deterministic approaches use a point forecast of wind power output, WPF uncertainty in the stochastic UC alternative is captured by a number of scenarios that include cross-temporal dependency. A comparison among a diversity of UC strategies (based on a set of realistic experiments) is presented. The results indicate that representing WPF uncertainty with wind power scenarios that rely on stochastic UC has advantages over deterministic approaches that mimic the classical models. Moreover, the stochastic model provides a rational and adaptive way to provide adequate spinning reserves at every hour, as opposed to increasing reserves to predefined, fixed margins that cannot account either for the system’s costs or its assumed risks.     

Sizing optimization of grid-independent hybrid photovoltaic/wind power generation system

To allow a real penetration of the huge dispersed naturally renewable resources (wind, sun, etc.) intermittent and more or less easily predictable, optimal sizing of hybrid renewable power generation systems prove to be essential. This paper recommends an optimal sizing model based on iterative technique, to optimize the capacity sizes of different components of hybrid photovoltaic/wind power generation system using a battery bank. The recommended model takes into account the submodels of the hybrid system, the Deficiency of Power Supply Probability (DPSP) and the Levelised Unit Electricity Cost (LUEC). The flow chart of the hybrid optimal sizing model is also illustrated. With this incorporated model, the sizing optimization of grid-independent hybrid PV/wind power generation system can be accomplished technically and economically according to the system reliability requirements. A case study is conducted to analyze one hybrid project, which is designed to supply residential household located in the area of the CDER (Center for Renewable Energy Development) situated in Bouzaréah, Algeria (36^° 48′N, 3^° 1′E, 345 m).     

Visualization of film wavelike characteristics and measurement of film thickness in spray cooling

An experimental investigation was performed to study the heat transfer in an eight-nozzle spray cooling system with de-ionized water as the working fluid. Visualization of the liquid-solid contact area and the flow near the heated surface was made using a microscopic lens system in conjunction with an advanced high-speed camera. The film thickness and film wavelike characteristics under liquid volume flow rates ranged from 2.78×10 -6 m 3 /s to 1.39×10 -5 m 3 /s and surface temperatures between 22℃ and 78.2℃ were examined respectively. The development process of the liquid film on the heated surface was observed. The local mean film thickness, the film wavelike characteristics and the behavior of the bubbles appeared in the liquid film were captured using an image processing technique. It is discovered that there exists a climax of local mean film thickness during the starting process of spray cooling. When the liquid film reaches the dynamic stable state, the dimensionless mean film thickness decreases with the increase of the liquid volume flow rate, and increases with the increase of surface temperature generally. Besides, the volume flow rate has a more significant impact on the wavelength and amplitude of the liquid film compared to the surface temperature.     

重力浓缩过程中底流浓度和比浓缩面积的确定

研究了重力浓缩过程中特征浓度线与沉积曲线之间的关系,利用两相流波理论分析了特征浓度线的初始性质．在此基础上,推导出计算连续浓缩机底流浓度和比浓缩面积的公式,并验证了这种新方法的可行性．     

Hydrodynamic Characteristics of Chinese Sturgeon Spawning Ground in Yangtze River

Since the construction of the Gezhouba Dam on the Yangtze River in 1981, it has been found that the Chinese Sturgeon, Acipensor sinensis, performs natural propagation annually in a narrow reach downstream close to the Gezhouba Dam site. This might allow one to better investigate the river hydrodynamic conditions of the Chinese Sturgeon spawning ground. In this article, spatial Kinetic Energy Gradient （KEG） and absolute value of vorticity were computed along the river sections from measured data. The relation between Spawn Density per Unit Area （SDUA） and vorticity strength and between SDUA and KEG were worked out. The Results showed that the vorticity and KEG were both effective parameters for describing the hydrodynamic characteristics of Chinese Sturgeon spawning ground. The Chinese Sturgeons prefer to spawn in the river sections where the value of vorticity strength is larger than 0.4 s^-1 and KEG is larger than 0.029 Jkg^-1m^-1.     

焦化装置弹丸焦生成的原因及对策

通过生成弹丸焦的实例分析,确定弹丸焦的生成主要与原料中含有较多的沥青质有关.残炭值与沥青质含量之比<1.4为生成弹丸焦的判定条件.指出通过降低炉出口温度、提高操作压力、提高循环比等措施可以抑制掸丸焦的生成,但提高循环比要根据原料情况而定,不适用于含较多轻组分的原料.     

三分量数字检波器电磁干扰产生的机理研究

数字地震检波器由于采用MEMS为核心的数字传感器技术,一般认为,已不存在传统地震模拟检波器所固有的50 Hz干扰,但是,实际应用却得出了不同的结论,而是在高压输电线附近存在电磁干扰,并且在强电场区此现象较严重。文章从取得的地震资料着手,展开系统研究,从信号的角度,分析形成的原因,并结合数字检波器的核心技术,从硬件系统的构成成分进行原理分析,在此基础上,进行野外试验。结果表明：MEMS技术并不能彻底消除电磁干扰影响,在电磁场较强或有漏电现象条件下仍然会引入电磁干扰,只是其干扰能量比动圈式检波器减弱。该研究为目前正在兴起的高密度地震资料采集中数字检波器的正确应用提供了参考。     

天然气净化厂单元能耗评价指标探讨

国内外天然气净化厂的设计普遍采用知名公司的过程流程模拟软件,为了达到理想的设计和节能效果,需要设计人员长期经验的积累。因缺乏国内外同类设计单元能耗水平的详细数据,以及现有单元能耗指标设置不够直观,评价难以达到SY/T 0082.3-2006《石油天然气工程初步设计内容规范》第3部分的要求。通过对A、B、C三个天然气净化厂主要设计参数的综合分析,提出脱硫单元用脱除每千摩尔酸气耗能;脱水单元用脱除每千摩尔水耗能;硫磺回收单元用酸气中每千摩尔硫化氢发生的蒸汽量,作为天然气净化厂新的单元能耗评价指标。同时统一能量折算指标和能耗计量器具。     

强化设备管理 延长开工周期实现最佳经济效益

介绍了大庆石化分公司炼油厂催化重整装置强化设备管理、延长装置开工周期、降低各种内耗、实现最佳经济效益的做法。     

国产清梳联合机的调试与工艺效果

介绍了国产清梳联合机的调试体会和对生条重量不匀率、含短绒率、棉结、杂质等质量参数的控制措施及工艺效果 ,并对加强生产技术管理和充分发挥设备性能提出了看法和建议。