Due to the intermittence and fluctuation of wind resource, the increasing penetration level of wind power will bring huge challenges to maintain the stability of power system. Integrating compressed air energy storage (CAES) system with wind farms can weaken this negative effect. However CAES system needs large caverns or mines to store compressed air, which is restricted in application. In this paper, a novel energy storage system based on liquid carbon dioxide is presented. The mathematical models of compressed liquid-carbon dioxide energy storage system are developed. The parametric analysis is conducted to examine the effect of some key thermodynamic parameters on the system performance. Compared with AA-CAES, the liquid carbon dioxide energy storage system has advantages such as a high energy density, high EVR. Moreover, the round trip efficiency of this system can reach about 56.64%, which is acceptable in consideration of the storage volume. Therefore, this proposed system has a good potential for storing wind power in large scale and offers an attractive solution to the challenges of the increasing penetration level of wind power.
总结了影响离心泵水力性能的因素,并针对机械损失、容积损失和水力损失的不同特征,在水力设计、模型制作已经定型的前提下,采用多种性能优化方法,结合工程实际设计了测试试验.经过一系列性能优化措施,离心泵的水力性能和运行性能均有不同程度的提高,达到了产品发布的节能指标.
为了研究立式粉体干燥器内不同粒径聚甲醛颗粒流动特性,采用CFD-DEM模型耦合液桥力模块的方法,分析了含水率和颗粒粒径对聚甲醛颗粒流动特性的影响,并验证了该分析方法的正确性.研究结果表明:基于量纲分析法,结合已有实验数据拟合得出平均颗粒速度的经验关联式,计算值与实验值的最大误差为25.13%,可以较好地描述干燥单元内的平均颗粒速度变化.截面平均固含率随着颗粒直径的增大而降低,干燥单元内固含率在轴向和径向分布上分别呈现"上浓下稀"、"边壁高近流体低"的特点.当颗粒直径dp＜2 mm且含水率Vlb≥0.1%时,容易造成干燥单元入口堵塞,并且干燥单元内固含率剧减.截面平均颗粒速度随着轴向高度和颗粒直径的增大而增大,从边壁区到近流体区域的局部颗粒速度逐渐减小.当颗粒直径相同时,湿颗粒比干颗粒的颗粒速度小;当颗粒直径超过临界值2mm时,随着含水率的增高,颗粒速度略微减小,颗粒平均停留时间和固含率总体上有所增加.
提出一种基于物联网技术的油田注水系统节能降耗方法,介绍系统组成和架构及其关键技术.以我国定边采油厂为例,对该系统的应用效果进行实例研究.结果表明:在定边采油厂引入基于物联网技术的油田注水系统节能降耗技术后,通过分析发现,注水量、注水压力、节流损失、注水泵运行效率对注水能耗的影响相对较大,通过采取合理的措施,每日节约无效注水量约 1.4 t,单井节约日电量约5.6 kW·h,实现了节约水资源和降低耗电量的目标.
为得到油藏水井压裂过程的优化参数,设计裂缝-油藏耦合技术设计油藏水井压裂参数优化数值模拟方法.建立油藏流体等效模型,设计控制单元结构模型,在法向速度的连续方程中,得到应力矢量的基线方程,并计算变化方程的平均渗流速度,设置数值模拟边界条件,得到油藏水井压裂的应力曲线,分别对压裂液黏度、压裂液注入量、支撑剂用量3个参数进行数值模拟.实验证明这3个参数对水井裂缝宽度与长度有直接影响,因此可以通过调节这3个参数实现油藏水井压裂参数的优化.
