一种基于主汽压预测的火电机组负荷控制方法

针对火电机组因锅炉大惯性导致负荷响应慢、汽压波动大等问题,提出一种基于主汽压预测的火电机组负荷控制方法.该方法以锅炉跟随控制方式为基础,根据预测模型,由负荷指令和当前燃烧率预测出主汽压变化趋势,根据预测主汽压与当前主汽压偏差来修正锅炉侧的能量需求,以超前改变入炉能量,提高机组的负荷响应速率,减少主汽压波动.以某1 000 MW超超临界机组为例,建立其压力预测模型并进行负荷控制阶跃仿真实验,结果表明:采用该方法使得燃料量控制兼顾快速性和准确性,能有效改善机炉之间协调特性,使机组负荷响应快、超调量小,同时主汽压波动小.     

Thermal-environment characteristics and comfort of combined radiant-floor （Korean heating system ondol） and convective cooling system

The thermal-environment characteristics of the existing forced-convection cooling system were compared with those of the convective cooling system, which combined the radiant-floor cooling system using floor-heating panel typically applied to apartments in South Korea with the forced-convection cooling system using improved fan coil unit. The subjective warm/cool-feeling responses to the combined radiant-floor and convective cooling system in the questionnaire survey conducted among the test subjects were analyzed to establish the basic data for the combined cooling system. The results show that in the thermal-equilibrium condition, the vertical air temperature difference in the model living room is larger in the forced-convection-cooling condition. Most of the subjects feel a proper warm/cool feeling on their entire body, but they feel colder on the foot and lower body in the combined-cooling condition.     

仿真技术在《单元机组集控运行》职业教育中的应用

为了全方位提升高职院校学生的岗位工作能力,充分发挥学生学习的主体性、创新性和团队协作精神,在《单元机组集控运行》职业课程教育中引入仿真技术。该技术的应用是本次课程改革的重要切入点。鉴于电力行业严格的安全生产要求．借助“虚拟电厂”作为职业训练平台,在课程内容整合成教学模块的基础上,职业技能训练与理论知识讲授相结合,贯穿整个教学过程。教学实践证明,理论教学与实践环节的紧密衔接使学生动手操作能力普遍增强．相关职业资格证书取证率高达98％,学生上岗适应期大大缩短。仿真技术应用于高职院校复杂岗位职业技能训练的课程教学模式值得推广。     

大型机组轴系对中方法探讨

针对大型机组的对中问题和常用的对中方法及适用范围进行了全面分析,采用激光对中仪进行大型机组轴系对中,测量精度高、操作简便、适用面广。分析了国内外激光对中仪的发展近况,根据目前国内相关研究讨论其不足之处以及发展方向。     

水厂消毒副产物的变化规律

三卤甲烷（THMs）和卤乙酸（HAAs）是给水厂中具有代表性的消毒副产物（DBPs）,如果水厂中消毒副产物生成量过高,将会影响到管网中水质安全。通过比较水厂2种不同处理工艺中各单元出水口的三卤甲烷、卤乙酸浓度变化,分析了消毒副产物DBPs浓度变化情况,讨论比较2套处理工艺水质处理效果。结果表明,水体经过折板反应池—斜板沉淀池—移动冲洗罩滤池处理后,出厂水中消毒副产物量的增加量相对水体经过机械搅拌澄清池—双阀滤池—处理后较小。     

快速随机Hough变换多直线检测算法

直线检测是计算机视觉和模式识别领域内的一项重要任务.针对现有随机Hough变换直线检测算法的无效采样量大、计算速度慢等缺点,在随机采样过程中提出了一种新的采样策略.我们先根据所有边缘点梯度方向的统计分布特征确定潜在直线的主方向,再通过设定的阈值消除K个分组边缘点集中对直线检测毫无贡献的点集.这样,不仅约束了随机Hough变换的采样范围,也减少了在随机采样过程中大量的无效采样,还使得算法速度得到提高、存储减少.最后通过仿真从检测单条和多条直线两方面出发对本文算法性能进行了分析.实验结果表明:算法能在实际噪声图像中快速提取出所有目标直线,对离散误差、局部断裂等缺陷不敏感,直线检测准确率也得到提高.     

严格遵守国家法令 规范煤炭设计市场

 针对目前煤炭设计市场存在的不执行国家制定的收费标准,恶意压价,扰乱了设计市场的情况,阐述了了解设计工作的地位和作用、贯彻国家规定的收费标准和规范设计市场的重要性,并强调杜绝压价恶意竞争,使煤炭设计市场走向良性发展应采用的措施。     

Development of a Membrane Distillation module for solar energy seawater desalination

Membrane Distillation (MD) processes are gaining growing interest among novel desalination technologies, in particular for small scale applications also coupled with non-conventional energy sources. In the present work an original laboratory scale planar geometry Membrane Distillation unit was designed, built and tested for future coupling with solar energy. Though conceptually simple, the original geometry was developed in order to allow for multi-stage arrangement, compactness, internal heat recovery and possible integration with a polymeric heat exchanger for final brine heating by means of solar energy or waste heat. The laboratory scale unit was tested in order to investigate the effect of operating conditions, i.e. hot feed temperature and flow rate, on the process performance, with particular attention paid to parameters relevant to the design of the system coupled with solar energy. Also the effect of different airgap configurations was investigated, namely (i) free airgap, (ii) permeate-gap and (iii) partial vacuum airgap arrangements.     

半集中式蒸发冷却空调系统特性的实验分析

介绍了半集中式蒸发冷却空调系统在新疆及西安某办公楼的设计过程,结合该办公楼结构形式采用了串联式空气-水系统。测试结果表明在新疆地区室外干球温度为35.0℃下,采用的三级蒸发冷却新风机组可使送风温度达到13.5℃,采用的间接-直接蒸发冷却复合冷水机组出水温度为16.5℃,室内维持在空调规范要求的舒适区域。西安测试结果表明室外干球温度为33.5℃下,采用的三级蒸发冷却新风机组可使送风温度达到17.4℃,采用的间接-直接蒸发冷却复合冷水机组出水温度为17.5℃。分析了该半集中式蒸发冷却空调系统的优缺点,为蒸发冷却空调系统的设计提供些许建议。     

Method and Apparatus for Precision In‐Line Sampling of Distillate

Abstract

In this short note we present a method and describe a simple apparatus for use with simple, fractional, and steam distillation operations in which the operator requires a precise measurement of instantaneous distillate composition as the distillation proceeds. There are many examples in which such a measurement will play a critical role. One such example is in the measurement of boiling or distillation curves, where one desires an explicit measure of distillation process temperatures as a function of distillate volume fraction. The ability to augment temperature‐volume distillation curves with composition information is very helpful. The optimization of critical distillation conditions for the separation of sensitive solutes is another example in which instantaneous distillate composition is of value. The purification of reactants before a reaction is still another example. In all of these cases, it is the instantaneous composition that emerges from the condenser that is needed, rather than the integrated composition of the distillate that accumulates in the receiver. In this note, the apparatus and method are described, and an example is given with a mixture of n‐decane/n‐tetradecane.