智能涡街流量计在合成氨厂天然气流量测量上的应用

天然气是一种多组分、复杂的混合气体、其流量的计过去采用同心直角孔板差压式流量测量方式,由于多种因素易引起测量误差。从涡街流量计简单的工作原理,使用实例介绍应用涡街流量天然气流量,提高天然气计量的准确度。     

涡街流量计在炼厂的应用

针对现代炼厂较少维护和低能耗的需求,涡街流量计在流量测量中应用的越来越广泛。本文比较了涡街流量计在国内外炼厂的应用现状,分析了涡街流量计在流量测量的优势,同时探讨了影响涡街流量计测量准确性的因素和对策。     

涡街流量计在化工行业流量测量中的应用

结合化工行业流量仪表应用的实践,介绍了涡街流量计的测量原理,涡街流量计的选择和安装。提出了在化工行业的流量测量中使用涡街流量计的注意事项。     

涡街流量计的技术改进研究进展

涡街流量计是根据涡街原理制备的测量气体和液体流量计量仪器,自上世纪八十年代以来被广泛使用,其技术也不断进步。本文就涡街流量计的旋涡发生体(阻流体)、检测元件(传感器)、前置放大器、滤波整形电路、D/A转换电路、输出接口电路等方面的技术特点和研究进展进行了综述,通过对涡街流量计原理的进一步的了解,期待有更好的改进思路,推动涡街流量计技术的进步。     

涡街流量计在蒸汽计量上的应用

蒸汽作为重要的二次能源用途非常广泛,蒸气流量的准确计量和蒸汽流量计的选型、安装有着非常密切的联系。涡街流量计是目前市场上应用非常广泛的蒸汽计量仪表,由于其无可动部件、可靠性高、量程范围宽等一系列优点,得到广大用户的认可,在蒸汽计量方面起着不可替代的作用。本文介绍了涡街流量计的基本原理和使用优势,分析了选型和安装时需要考虑的问题,并重点对高温蒸汽影响测量精度方面进行了探讨,提出了针对策略,对于用涡街流量计来计量蒸汽的应用有一定的帮助。     

涡街流量计测量气液混相流的不确定度

涡街流量计可用于部分混相流的测量,但迄今为止有关混相流对涡街流量计测量特性的影响还缺少理论研究和实践经验.在体积含气率为2.0%～15.0%的范围内,评定了用涡街流量计测量气液混相流的不确定度,提出涡街流量计测量气液混相流的不确定度计算式.实验以空气和水为介质产生气液混相流,涡街信号通过管壁差压法采集,涡街频率通过功率谱分析获得.结果表明在保持涡街流量计一定测量准确度的前提下,涡街流量计相对扩展不确定度随气液混相流流量及其体积含气率的分布比较均匀;在涡街频率测量的不确定度分量中,由重复性和复现性引起的相对标准不确定度随流量的变化呈现出较强的随机性,而由频率分辨率引起的相对标准不确定度则随着流量的增加而减小.在本研究的流量与体积含气率范围内,由气液混相流引起的涡街流量计附加相对不确定度小于2.0%.这一研究为分析气液混相流对涡街流量计测量特性的影响提供了有益的借鉴.     

涡街流量计在石油化工行业中的应用

涡街流量计是现代石油化工行业中测量流量的重要工具之一;简述了涡街流量计的测量原理和主要优点,提供了涡街流量计的选型、安装、使用和维护的建议;通过规范设计、合理选型、正确的安装和维护,让涡街流量计在石油化工行业中发挥更大的作用。     

影响涡街流量计测量准确度的几个因素

涡街流量计是生产中测量流量的重要工具之一。文章简述了涡街流量计构测量原理、基本结构,洋细分析了影响涡街流量计测量准确度的选型、安装、温度压力补偿、旋涡发生体迎流面堆积、配管内径与流量计内径不一致等因素,并提出了解决影响测量精度的具体方案。     

丹尼尔超声波流量计在LNG计量的应用

丹尼尔超声波流量计是一种用于测试天然气产量的计量设备,它具有抗干扰能力强、测量范围宽、易维护流量测量的影响因素少、测量精度高等特点,可以有效的提高超声波流量计计量天然气的精确率。     

气体超声流量计的分析与应用

<正>随着科学技术的发展和天然气流量测量技术研究的深入,近年来超声流量计在天然气贸易计量中得到了广泛的应用。我国于2001年内编制了GB/T 18604《用气体超声波流量计测量天然气流量》的国家标准。该类型教其它流量计有自身有点,因此近些年来除中石油西气东输管线应用超声流     

Improvements in the two-parallel-condenser model of the double layer in the presence of organic adsorption

Previous recent attempts by the author for giving a more consistent physical meaning to the two-parallel-condenser model and its implications on the adsorption isotherm behaviour are reviewed. In addition, the displacement of oriented water molecules by the adsorbate is taken into account and the effects of a series capacity are discussed. This allows to consider the original expression for the charge density as a function of potential as an approximation of a model much more complex than that first treated. The new expression for the limiting capacity at maximum coverage still allows a consistent analysis from the corresponding experimental parameters.     

PIG清焦技术在炼厂加热炉的实践

某厂焦化装置加热炉对流段结焦严重需要清焦,通过比较各种清焦技术的利弊,采用了清焦效果好、对炉管损伤小、工期短、安全环保的PIG清焦技术,清焦后加热炉运行效果良好,延长了装置的开工周期,具有很大的推广价值。     

Kinetics of the Washing of Granules in the Melt

The mechanism and rate of the melt extraction of eutectic-forming impurities from granules of organic substances are considered. A diffusion model is suggested for this process, and kinetic relationships taking into account the relative closed porosity are derived for calculating the purification efficiency for granules of various shapes and sizes. The solutions obtained are compared with equations known from the theory of countercurrent crystallization and other mass-transfer processes. Experimental purification efficiency data are presented for washing caprolactam granules in a tank apparatus and a countercurrent column. These data are consistent with the suggested washing model. The possibility of the intensification of mass transfer by promoting recrystallization in the granules–melt system by ultrasonic treatment and thermal cycling is analyzed.     

Influence of shear in the crystallization of polyethylene in the presence of SWCNTs

It is well accepted that due to epitaxy matching, carbon nanotubes are good nucleating agent for linear polyethylene. We demonstrate that not only in the quiescent conditions but also at the relatively low shear rates the presence of single-walled carbon nanotube (SWCNT) accelerates the crystallization kinetics of polyethylene (PE). The influence of SWCNTs on the crystallization kinetics in the quiescent condition is followed with the help of rheological and differential scanning calorimetry studies. The influence of flow on the stretch of the polymer chain is probed using time-resolved small-angle X-ray scattering (SAXS) and is verified with the Deborah number. SAXS data indicates that the strong shearing conditions (shear rate > 50/s for 1 s) are requisite to form shish-kebab structure in the neat polymer. However, for the low shear (shear rate < 50/s for 1 s), the shish-kebab structure that arises due to chain orientation is enhanced in the presence of SWCNTs. The development of oriented structures in SWCNT/PE composites and their absence in the neat polymer under low shear rate indicates that the presence of SWCNTs plays a significant role in the chain orientation. Overall, the results manifest the influence of SWCNTs on chain relaxation of the polymer.     

On the convergence of costs in the problem of optimal stopping of stochastic processes in the scheme of kalman-bucy

We obtain the bound of order ? for the difference between the costs of optimal stopping problems for completely and partially observable cases when the partially observable stochastic process contains a small ? parmeter. The key step in teh analysis is an introduction of the auxiliary standard normal variablen and the subsequent change of time.     

微通道内火焰传播的研究进展

微燃烧器与阻火器淬火单元均为可燃气体燃烧的微通道,目前对微燃烧器的研究较充分,而对阻火器淬火单元的研究较少. 本工作概述了影响火焰在微通道内传播的因素,指出对各因素的研究还需深入,有利于澄清争议;简述了火焰在微通道内传播的数学模型的研究进展,提出微通道内流体流动流型的判定亟需完善;确定在高速爆轰条件下,阻火器内的流动为湍流;推荐将雷诺应力湍流模型与层流有限速率模型结合进行阻火器内高速爆轰火焰传播的数值模拟,推荐采用以密度为基础的算法进行求解;指出了微通道内火焰传播研究的成果与不足,展望了其发展方向.     

CFB用旋风分离器内气相流场的数值研究

采用RSM非稳态湍流模型对循环流化床锅炉用旋风分离器内气相流场进行了数值模拟。计算值与实验值比较吻合。数值计算的结果表明:排气管下口存在明显的短路流,排尘口附近存在明显的返混现象;排气管直径增加,分离空间切向速度值降低,上行流轴向速度减小。用CFD方法计算的旋风分离器内流场可为高效CFB锅炉用旋风分离器的设计提供参考依据。     

Study of the Role of the Tyrosine Kinase Receptor MerTK in the Development of Kidney Ischemia-Reperfusion Injury in RCS Rats

Renal ischaemia reperfusion (I/R) triggers a cascade of events including oxidative stress, apoptotic body and microparticle (MP) formation as well as an acute inflammatory process that may contribute to organ failure. Macrophages are recruited to phagocytose cell debris and MPs. The tyrosine kinase receptor MerTK is a major player in the phagocytosis process. Experimental models of renal I/R events are of major importance for identifying I/R key players and for elaborating novel therapeutical approaches. A major aim of our study was to investigate possible involvement of MerTK in renal I/R. We performed our study on both natural mutant rats for MerTK (referred to as RCS) and on wild type rats referred to as WT. I/R was established by of bilateral clamping of the renal pedicles for 30′ followed by three days of reperfusion. Plasma samples were analysed for creatinine, aspartate aminotransferase (ASAT), lactate dehydrogenase (LDH), kidney injury molecule -1 (KIM-1), and neutrophil gelatinase-associated lipocalin (NGAL) levels and for MPs. Kidney tissue damage and CD68-positive cell requirement were analysed by histochemistry. monocyte chemoattractant protein-1 (MCP-1), myeloperoxidase (MPO), inducible nitric oxide synthase (iNOS), and histone 3A (H3A) levels in kidney tissue lysates were analysed by western blotting. The phagocytic activity of blood-isolated monocytes collected from RCS or WT towards annexin-V positive bodies derived from cultured renal cell was assessed by fluorescence-activated single cell sorting (FACS) and confocal microscopy analyses. The renal I/R model for RCS rat described for the first time here paves the way for further investigations of MerTK-dependent events in renal tissue injury and repair mechanisms.     

间苯二甲酸二甲酯-5-磺酸钠生产中中和工艺的研究

针对间苯二甲酸二甲酯-5-磺酸钠(SIPM)在工业化生产中的关键工序-中和反应对产品质量、收率、成本、杂质含量、应用效果等影响较大而国内同行业对比研究甚少,利用液相色谱法对中和物料的纯度、中和离心后的废液中SIPM及硫酸钠含量进行了分析,对中和工艺进行了深入研究。确定了最佳中和条件:在30℃下,中和反应最佳pH值为6.5,产品纯度可达到99.5%以上。     

二甲醚合成机理的研究进展

合成气在双功能催化剂上一步法制取二甲醚的反应机理,主要涉及甲醇合成和甲醇脱水两个反应,重点论述了甲醇合成的碳源问题和甲醇脱水的活性位问题。甲醇合成的碳源主要有CO、CO2和双碳源3种,甲醇脱水的活性中心位主要包括强酸中心、弱酸中心和双活性中心。