3-D computational fluid dynamics for gas and gas-particle flows in a cyclone with different inlet section angles

A three-dimensional computational fluid dynamics (CFD) Reynolds stress model (RSM) was used to describe the gas and gas-solid flow in a cyclone with a scroll inlet duct at three different inlet section angles in relation to the cyclone body. The effects of the inlet section angles on the fluid dynamics inside the cyclone and on the performance parameters (collection efficiency and pressure drop) were analyzed by means of the finite volume method using a computational code and an industrial-sized cyclone for separation of gas-particle phases operated by Votorantim Cimentos Company. The numerical results show that the value for overall collection efficiency in this work increased to 77.2% for the 45° inlet section angle, while that for the normal inlet duct was 54.4% under the same operating conditions.     

低入口浓度下微旋风分离器的试验研究

设计了公称直径75mm的微旋风分离器,在低入口浓度下对其进行试验研究.结果表明,该微旋风分离器的分离效率随着流量的增加先上升后下降,并随入口浓度的增加而上升,在雾滴平均粒径为31 μm、流量为56Nm3/h、入口浓度为12.4mg/L时,分离效率在78.3％以上,适用于加氢裂化工艺中循环氢的脱硫处理.笔者根据实验数据还...     

燃气轮机压气机可调进口导叶技术浅析

压气机是燃气轮机的重要组成部件之一,其进口导流叶片（inlet guide vane,简称IGV）安装在第1级动叶前,用来控制进入第1级动叶前的气流方向。介绍了IGV的结构;简述了2种可调IGV的控制方式;分析了可调IGV对燃气蒸气联合循环性能的影响;列举了可调IGV技术的工程应用效果。结果表明,在联合循环机组中采用连...     

基于LSTM的阀冷系统入水温度及冷却裕度预测

为解决换流站阀冷系统状态缺乏智能预测手段和极端工况下冷却能力是否充裕难以评估的问题,提出基于长短期记忆网络(long short-term memory,LSTM)的换流阀冷却裕度预测方法.在阀冷系统冷却裕度指标量化评估的基础上,考虑多源影响因素,通过相关性强弱选择特征量并构建数据样本集,利用长短时记忆网络建立预测模型...     

不同形式导流板对旋风器性能影响的试验研究

通过对加设不同形式导流板的旋风器进行试验研究,结果表明:不同形式导流板均不同程度地降低了旋风器阻力,同时也对分离效率产生了不同的影响.其中3#、4#导流板降阻幅度较大,但分离效率相对较低;2#的降阻效果强于1#,但弱于3#、4#,同时并没有降低分离效率;1#导流板只在一定限制条件内有减阻效果,其总体分离效率却比较高.     

影响预分解窑窑尾物料填充率的因素分析

确定合理的物料填充率是稳定窑内热工制度的前提,窑尾物料填充率过高会导致窑尾漏料事故的发生.引起窑尾物料填充率变化的因素主要有入窑物料量、窑的转速、窑尾温度、预分解系统温度以及窑皮的长度和厚度、结圈等.生料易烧性发生变化,窑头用煤量过多或不完全燃烧,燃烧器使用不当等都可能导致窑皮长度和厚度的变化.     

往复式 CO2压缩机五段入口温度的优化

分析了往复式CO2压缩机五段入口温度控制难度较大的原因;采取了定期清洗压缩机酸排、增大脱硫槽容积、调整压缩机四段冷却器用水流程等优化措施.改造效果表明,CO2压缩机五段入口温度的波动范围为±2℃,达到指标要求.     

二氧化碳压缩机提板阀波动原因探讨与对策

1概述 大庆石化公司化肥厂尿素装置二氧化碳压缩机控制机构经改造后,采用3+系列防喘振控制系统,速度控制部分主要由3+系列的速度控制器(SIC112)、抽气控制器(PIC920)、注气控制器(PIC901)及油路环节(包括油系统过滤器、分油器、电液转换器、油动机等)所构成.控制器SIC112、PIC920、PIC901输出4～20mA电流信号,完成常规PID控制;油路环节实现电液信号转换,最终驱动3个提板阀V1、V2、V3动作,达到对转速的控制.控制系统构成如图1所示.     

色谱分析501抗氧防胶剂纯度及游离甲酚含量

采用毛细管气相色谱技术，使用二甲基聚硅氧烷毛细管色谱柱，利用程序升温、程序升压及分流进样法，通过实验选择最佳分析操作条件，较成功地测定出501抗氧防胶剂纯度及其游离甲酚含量。     

Study on the floatation mechanism and floatation performance for the floatation cyclone of natural inlet air

A novel structure floatation cyclone of natural inlet air has been designed, and its structural characteristics and floatation principle have been analyzed. The velocity and pressure distributions within the flow field of the floatation cyclone have been studied by Navier-Stokes equations. Based on the flow characteristics of the mixture of fine coal and water, reasonable boundary conditions are decided and the equations are modified, so that the final equations can describe the real flow state of the flow field of the floatation cyclone. The boundary surface position between float coal and tailings is determined and there is an air cylinder in the central region of the floatation cyclone. The research reveals the floatation mechanism of the floatation cyclone. The floatation results can be greatly improved by regulating the structural dimensions of cyclone. The experimental results show that the floatation cyclone is very effective for the floatation of fine coal grains.