海上含液天然气流量计开发

阐述在线多相流量计的开发原理和国内外低含液率气液两相流计量技术研究的主要技术路线.结合海上含液天然气流量计开发工作,全面系统地总结了流量计开发的技术路线和研究成果.详细介绍槽式孔板的单相流与两相流测量特性、基于双槽式孔板组合测量原理与软测量技术的流量计计量算法等内容,指出了需要进一步深入研究的方向.     

孔板流量计在天然气流量计量中的应用

由于历史缘由和本身的特性,孔板流量计在当前天然气计量中占领很大市场。同时,由于自动化技术在孔板流量计计量系统中的应用,使孔板流量计计量系统克制了传统计量过程中人为误差等不利要素,进一步进步了孔板流量计的计量精确度。     

槽式孔板的湿气分层流差压预测模型

槽式孔板是一种新型的气液两相流测量元件,与标准孔板相比,槽式孔板具有前后直管段要求低、差压信号平稳、上游液相无累积等优点。通过对槽式孔板的局部阻力进行分析,槽式孔板总压降主要由摩阻压降和加速压降两部分组成。基于气液两相流体流经槽式孔板的流动机理,利用动量守恒关系式和能量守恒关系式计算摩阻压降和加速压降,建立了槽式孔板的分层流差压预测模型。以空气/水为介质,进行了一系列实验,实验结果表明,孔径比为0.75、0.6、0.5的槽式孔板的平均相对误差分别为6.45%、11.06%、12.52%,为湿气计量算法的完善提供了参考。     

孔板流量计对天然气输差的影响

孔板流量计是计量天然气的主要工具,但计量得到的数值较容易产生误差,天然气的输差主要来源于管储量计算、阀门或管道泄漏和计量系统误差等。此外,受计量时间与气体组分的影响,天然气的计量误差也会存在。因此,对于天然气输送时的各种误差,有必要明确各项误差的根源,结合孔板流量计应用于天然气输送的现状,探究具体的输差影响。     

天然气回流对孔板流量计上下游截面压力影响分析

针对天然气回流工况对孔板流量计上下游截面压力的影响问题,依据现场数据,采用solidworks软件建立DN150标准孔板流量计几何模型,基于CFD软件对此状态下孔板流量计内部流场进行数值模拟分析。研究发现:管内天然气回流工况越严重,对孔板流量计上下游截面压力变化影响越大。随着管输量的增加,回流程度逐渐平缓,孔板处流动几乎不受上游回流涡旋的影响,上下游截面压力变化幅度较为稳定,对孔板流量计精度影响也随之降低。     

槽式孔板的气液两相压降倍率特性

简要介绍了一种新型气液两相流量传感器——槽式孔板的工作原理,在分析两相流体与槽式孔板相互作用机理的基础上,结合实验数据和理论模型详细分析了影响槽式孔板两相压降倍率的各种因素.利用曲面拟合技术给出了能够准确表征槽式孔板两相压降倍率与压力、气体Froude数、Lockhart-Martinelli参数之间的相关式,为凝析天然气计量技术研究奠定了基础.     

槽式孔板的低含液率气液两相流测量特性

槽式孔板是一种新型气液两相流量传感器,目前尚未发现能够应用于槽式孔板的两相流压降相关式,结合空气/水两相流实验数据,比较了五类典型的标准节流元件两相流压降相关式对槽式孔板测量数据的计算结果,分析了这些相关式的适用范围和误差原因。基于不同的建模思想,综合考虑洛—马参数、介质压力、气相流量等参数的作用,建立了三种相对准确的槽式孔板两相流压降相关式,并将其应用于低含液率的凝析天然气计量技术研究,计算结果表明三种相关式均能达到工业计量的精度要求。     

浅谈孔板流量计的使用和测量误差

孔板流量计是一种广泛应用于化学工业的流量测量仪表。它在安装、使用和维护等方面存在很多的不足,从而容易产生流量测量的误差。通过对孔板流量计的研究,提出引起流量测量误差的各种原因。通过补偿和技术改造等措施对测量误差进行了修正,从而保证了流量测量的准确性和实效性,这对于孔板流量计的准确计量具有一定的指导作用。     

天然气流量计在徐深1区块的应用

通过对徐深1区块计量中孔板流量计、旋进漩涡流量计等存在问题的提出和分析,找到相应的有效解决办法,保证正常生产。     

孔板流量计测量误差及产生的原因和解决的方法

在孔板流量计运行中,为了更好地将火焰探测器的误报频率降低,分析了孔板流量器测量误差的原因及其解决方法,以更好地确保火焰探测的稳定性和有效性。     

输入训练神经网络的维数约简算法及其在化工过程建模中的应用

Many applications of principal component analysis （PCA） can be found in dimensionality reduction. But linear PCA method is not well suitable for nonlinear chemical processes. A new PCA method based on improved input training neural network （IT-NN） is proposed for the nonlinear system modelling in this paper. Momentum factor and adaptive learning rate are introduced into learning algorithm to improve the training speed of IT-NN. Contrasting to the auto-associative neural network （ANN）, IT-NN has less hidden layers and higher training speed. The effectiveness is illustrated through a comparison of IT-NN with linear PCA and ANN with experiments. Moreover, the IT-NN is combined with RBF neural network （RBF-NN） to model the yields of ethylene and propylene in the naphtha pyrolysis system. From the illustrative example and practical application, IT-NN combined with RBF-NN is an effective method of nonlinear chemical process modelling.     

基于变长度移动窗口和HMM的工业过程故障在线诊断

An integrated framework is presented to represent and classify process data for on-line identifying abnormal operating conditions. It is based on pattern recognition principles and consists of a feature extraction step, by which wavelet transform and principal component analysis are used to capture the inherent characteristics from process measurements, followed by a similarity assessment step using hidden Markov model (HMM) for pattern comparison. In most previous cases, a fixed-length moving window was employed to track dynamic data, and often failed to capture enough information for each fault and sometimes even deteriorated the diagnostic performance. A variable moving window, the length of which is modified with time, is introduced in this paper and case studies on the Tennessee Eastman process illustrate the potential of the proposed method.     

槽式孔板气液二相流差压信号的时间序列分析

槽式孔板是一种新型的气液二相流流量传感器,为了研究其二相流测量特性,提出了一种新的信号处理方法。首先应用小波变换模极大值滤波方法对差压测量信号去噪,然后对滤波结果进行经验模式分解得到有限个经验模式函数(IMF),进而对IMF建立自回归(AR)模型,研究了AR模型的参数与气液二相流流型以及分相流量之间的关系。这种信号处理方法能够使具有非平稳特性的差压信号满足时间序列分析的建模条件,AR模型的参数可以有效地区分气液二相流流型,并与气液分相流量的变化密切相关,为气液二相流流型识别和流量计量算法的研究奠定了基础。     

使用加热空气的预混天然气催化燃烧的实验研究

In this paper the premixed catalytic combustion emissions such as CO, unburned hydrocarbon （UHC）, NOx and the temperature distribution in the catalytic monolith with ultra low concentration of Pd were studied. Three types of monoliths were used for experiments and the temperature of preheated air was respectively 50℃, 100℃ and 200℃. The results showed that preheated air made radial temperature in the catalytic monolith uniform which helped to avoid local hot spots so as to decrease NOx emission. The experiment also proved that the shorter monolith showed much better catalytic combustion performance than longer one and the temperature at the exit of the shorter monolith was relatively lower. On the contrary, the temperature was higher in the longer monolith and the lethal NOx emission was slightly increased.     

基于神经网络的水平文丘里湿气测量模型

文丘里流量计用于湿气测量需要对因液相的存在而产生的读数偏高（虚高）进行修正。文中分析了8个经典的文丘里湿气测量虚高模型的特点与局限,用分相模型理论结合神经网络曲线拟合方法得到了一个新的文丘里湿气测量模型,并对模型进行了验证,结果证明模型对文丘里湿气测量虚高特性的预测较准确,误差在5%以内。模型的适用范围宽,经大量实验验证并与8个传统模型作了对比,结果表明模型在压力P〖HTSS〗为0. 15～6. 0 MPa,孔径比β〖HTSS〗为0. 4～0. 75,气相Froude数Fr g为0. 5～5. 5,LM参数X为0. 002～0. 3,质量含气率x为0. 5～0. 99范围内均得到满意的预测结果。     

基于人工神经网络的滴流床脉冲流频率的预测

An extensive database (946 measurements) for the frequency of pulsing flow in trickle beds was established by collecting the experimental results published over past 30 years. A new correlation based on artificial neural network (ANN) to predict the pulsation frequency was developed. Seven dimensionless numbers (groups) employed in the proposed correlation were liquid and gas Reynolds, liquid Weber, liquid Eǒtvǒs, gas Froude, and gas Stokes numbers and a bed correction factor. The comparisons of performance reported in the of literature and present correlations show that ANN correlation is a significant improvement in predicting pulsation frequency with an average absolute relative error (AARE) of 10% and a standard deviation less than 18%.     

水平管内气液段塞流液塞长度发展规律的实验和模拟研究

In petroleum industry, the slug flow is a fre-quently encountered flow regime in multiphase flowpipeline. For pipeline designers, the liquid slug lengthdistribution is important for the proper design ofdownstream facilities, such as slug catcher and sepa-ration system. However, for its transient and unsteadynature, it is a great challenge for engineers to correctlypredict the flow parameters of slug flow, especiallythe maximum liquid slug length. The unit cell model for slug flow in horizontal…     

基于独立成分分析的水平管气液两相流分相信息提取

基于独立成分分析(ICA)方法分析水平管气液两相流的电阻成像（ERT）所获取数据,提取水平管气液两相流流动特征,获取分相信息。通过分析比较ICA所得的独立分量以及ERT侧视、俯视成像时间序列和摄像仪记录的流动状态图像,并经过实验表明,对水平管气液两相流中的弹状流、分层流、波状流,电阻层析成像方法结合ICA方法可有效地获取水平管气液两相流流动特征参数,提取的独立分量反映了物理上相互独立的分相的变化情况,具有明确的物理意义;对水平管气液两相流中的塞状/泡状流,ICA方法结合多尺度分析方法可获得更为有效的信息。