离心泵输送胜利油田孤岛地区高粘原油时工作特性计算方法

考虑粘度影响的离心泵工作特性是原油长输管道优化运行的基本依据之一,文献[1]提出了一种了简捷算法,但没有给出泵效换算系数的具体拟合公式,且适用的粘度范围有限。针对胜利油田孤岛地区原油粘度高的特点,在文献[1]的基础上,从美国水力学会绘制的离心泵特性曲线换算图上读取粘度在65~1760mm2/s范围内的泵特性参数换算系数,通过多参数非线性拟合,得到了泵效换算系数随泵额定流量、单级扬程和流体粘度的变化关系;以此为基础,建立了清水条件下泵特性给定时考虑粘度影响的泵特性计算方法。通过对现场运行的某型号离心泵两千多个工况点粘度、流量和扬程数据的采集,对预测和实测扬程进行了对比,相对误差大多在±10%以内。     

介质黏度对离心泵性能的影响

为了获得介质黏度对离心泵性能的影响规律,采用CFD方法对输送3种不同黏度介质的同一台离心泵进行了数值模拟.外特性结果分析表明,清水介质下扬程及效率实验和模拟结果之间的偏差随流量的增大而减小;不同黏度介质下离心泵的外特性曲线的趋势基本一致,即随着介质黏度的增大,效率下降,扬程减小,功率增大;不同黏度下功率换算系数Kp>1,流量换算系数Kq<1,扬程换算系数Kh<1,效率换算系数Kη<1.泵内部静压分析表明,随着介质黏度增大,泵进出口压差减小,泵内流动损失增大.     

有机朗肯循环系统中工质泵的运行性能

为研究车用有机朗肯循环（organic Rankine cycle,ORC）余热回收系统中工质泵的性能及选型,在模拟车用ORC余热回收系统的工作环境下,设计并搭建了以R123作为工质的多级离心泵性能测试实验系统。通过控制多级离心泵转速（870~2900 r·min^-1）、调节工质流量（0.20~5.00 m³·h^-1）,得到了多级离心泵特性曲线。通过分析变工况时多级离心泵关键参数间相互作用关系,及其对车用ORC余热回收系统性能的影响情况,验证了多级离心泵应用于车用ORC余热回收系统的可行性,并确定了其最佳工况点参数。研究结果表明：变工况时,多级离心泵总效率为15.00%~65.70%。车用ORC余热回收系统的蒸发压力、热效率均随着多级离心泵转速的增加而增加。在高转速区,工质流量对系统蒸发压力和多级离心泵输入功率（多级离心泵消耗的电功率）的影响明显增大。随着系统蒸发温度的升高,工质泵实际输入功率占膨胀机输出功率的比例（back work ratio,BWR）最高可达0.45。当多级离心泵转速为2900 r·min^-1时,车用ORC余热回收系统热效率最高可达10.50%。     

高速泵效率影响因素的正交试验研究

现代高速离心泵的设计要求效率高、运行范围广、水力性能好,如何提高效率是高速离心泵设计的重点与难点。文章基于GSB-W5型卧式高速离心泵开展水力性能试验,针对小流量、高扬程、高转速离心泵效率的试验统计数据开展正交试验研究,探索泵流量、扬程、转速等工艺参数对泵效率的影响规律与影响趋势。研究结果表明,流量对泵效率的影响最大,扬程的影响次之,转速的影响最小;随着流量增大泵效率逐渐增大,泵效率则随着扬程、转速的增大逐渐减小。     

离心泵性能曲线对设计选型影响的探讨

性能曲线是离心泵选型的基础。针对工程中离心泵特别是多级离心泵选型中的几个参数,包括最小连续流量、关闭扬程以及并联泵性能曲线匹配对泵运行稳定性和安全性的影响,进行了研究及探讨。     

浅析石化企业离心泵的汽蚀及提高其抗汽蚀性能的措施

离心泵是石油化工企业运用最广泛的输能流体机械。在使用过程中怎样防止离心泵的汽蚀,怎样去减少汽蚀对离心泵的损害是非常重要的。汽蚀是一种十分有害的现象,它使离心泵的扬程,流量和效率明显下降,严重时泵甚至不能够运转,所以研究泵的汽蚀并采取相应的措施有助于提高泵的使用效率和延长泵的寿命等。     

LINEST函数在离心泵流量-扬程性能曲线拟合中的应用

基于最小二乘法原理,利用EXCEL软件中的LINEST多元线性回归函数,对泵产品样本上给定的离心泵流量-扬程(Q-H)性能数据进行了拟合。结果表明:由回归方程所得到的扬程拟合值与实际泵样本值的误差均在±0.5%以内,且在利用LINEST函数对离心泵Q-H性能曲线进行拟合时,操作上简单、便捷,还能对回归效果进行显著性检验。     

比较加工不同粘度密度的原油能耗

千克标油/吨原油能耗是考核炼化企业经济效益优劣的一项重要综合指标,其中包括离心泵输送原油能耗.本文根据原油粘度、密度对离心泵特性曲线影响的不同,比较轴功率的变化.     

高黏含水原油外输泵的优化选型研究

塔河油田6区所产原油为高黏原油,开发初期计转站所建的外输泵为双螺杆泵,随着原油含水率升高,原油黏度波动大,外输效率降低,外输压力达不到设计要求。为了解决外输泵效率低、泄露严重的问题,通过取样化验获得60%～80%含水率对应的原油黏度,以此为基础对比分析双螺杆泵、离心泵和单螺杆泵的适用性。最终确定由单螺杆泵代替双螺杆泵作为高黏含水原油的外输泵。     

基于Visual Basic编程对离心泵性能曲线的拟合

在分析拟合离心泵性能曲线必要性的基础上,以拟合离心泵流量和扬程性能曲线为例,介绍了利用最小二乘法使用visual Basic语言进行直接编程拟合曲线的方法;经实际使用本程序具有简单、易用、求解效率高、适用范围广等特点,有效解决了石化行业中离心泵选型、试验中曲线拟合的数据处理问题,可以在离心泵及容积泵性能曲线拟合中推广应用。     

Humic acids from lignite. 1. Analytical characteristics and thermal degradation

Humic acids (HA) extracted from a lignite with two alkaline reagents have been studied. In contrast to humic acids extracted from soil HA, the lignite acids show no differences in their physical and chemical analyses with the exception of the total carbonyl content. After acid hydrolysis the analytical characteristics do not change, but their behaviour on Sephadex indicates a molecular condensation. The parent material has similar characteristics to those reported in the literature and also shows no analytical differences after acid hydrolysis, but a number of i.r. absorption bands, due to kaolinite, the only clay mineral present, disappear after this treatment. By pyrolysis/gas chromatography both the lignite and the humic acids produce several low-b.p. compounds, the same in the three cases but in different amounts. By methylation it has been proved that a great part of such compounds are produced by radical reactions. Some, which do not increase on methylation, may indicate the presence of some longer chains in lignites.     

Catalytic ozonation of humic acids with Fe/MgO

Humic acids were degraded by ozone at room temperature in a stirred tank reactor and a fixed bed reactor with Fe/MgO catalysts. Experimental results show that the ozonation with Fe/MgO induced a significant reduction in UV absorbance of humic acids as compared to ozone alone. Fe/MgO was the most efficient catalyst to degrade humic acids in the presence of ozone. GPC (gel permeation chromatography) showed that the humic acids with high molecular weight could be severely decomposed into organic compounds with low molecular weight on the Fe/MgO catalyst, indicating that humic acids could be catalytically decomposed. The continuous reaction experiments with the palletized catalysts supported that humic acids can be removed by catalysis as well as adsorption.     

腐植酸是关怀人类的新产业

腐植酸是关怀人类的新产业。腐植酸是一类天然大分子有机化合物的混合物,具有环境保护者和人类关怀者的"秉性"。腐植酸的物理、化学和生理特性,为各行各业开发应用提供了科学依据。用腐植酸开发的产品,以其天然环保的自然属性和安全可靠的使用价值,在大环境、大农业、大工业、大发展中,已经成为产业关注的热点。从自然中来,到自然中去,高扬腐植酸绿色大旗,打造腐植酸关怀人类的新产业,为国民经济第一、二、三产业发展甘当"绿叶"而大显"富贵"。朴素中凸现高贵,高贵中彰显温和,这就是对腐植酸新产业的最好诠释。     

珠江河口水体沉积物中腐殖酸的提取与表征

采用NaOH碱提法提取和纯化了珠江河口水体沉积物中的腐殖酸,并用元素分析、傅立叶变换红外光谱、透射电镜、原子力显微镜等方法对提取的腐殖酸进行了表征。结果表明,提取的腐殖酸由C、H、O、N、S元素组成,含有羧基、羟基等多种活性官能团,其中芳香族不饱和物质较多;透射电镜观察发现在较高浓度时腐殖酸聚集体呈现枝状结构,原子力显微镜扫描发现,腐殖酸胶体粒子在较低浓度时呈球形聚集体形貌,直径在100 nm左右。     

土壤腐殖酸的提取及表征

从土壤中提取腐殖酸样品,并用物理和化学等方法对其进行了表征。同时,对提取过程中的一些问题如氮气保护、纯化也做了探索。结果表明有无氮气保护对最终产物无明显影响;ＨＦ－ＨＣｌ混酸能降低样品灰份;本腐殖酸含有的芳香结构较多,属大分子量低腐殖化的腐殖质级分     

褐煤粒度对碱法制备胡敏酸和富里酸的影响

以不同粒度的白音华褐煤碱性煤浆为原料,5%(质量分数,下同)NaOH溶液和1 mol/L H2SO4溶液为pH值调节剂,制备胡敏酸和富里酸。通过容量法和紫外可见分光光度法分析胡敏酸和富里酸的含量、提取率、E4/E6值和DPPH(1,1-二苯基-2-三硝基苯肼)抗氧化活性,探讨褐煤粒度对胡敏酸和富里酸的影响规律。结果表明:当褐煤粒度减小到13.28μm时,胡敏酸和富里酸的总提取率为86.34%,胡敏酸与富里酸的分子量和芳香缩合度最为相似。该粒度条件下,富里酸的提取率可达62.28%,游离腐植酸质量分数为47.4%,DPPH自由基清除率为41.3%,富里酸的抗氧化活性显著。     

腐植酸的增氮解磷促钾作用

腐植酸对化学肥料有明显的调控和增效作用,主要表现为对氮、钾缓释,对磷活化,从而提高了化肥的利用率。作者从理论上阐述了腐植酸增氮解磷促钾的调控机理,也通过一些实例证明了化学肥料与腐植酸结合后显著的增产效果,论证了在化学肥料中添加腐植酸对减少化肥用量、提高作物品质和保护环境方面的积极意义。     

The Potassium Permanganate Oxidation of Methylated and Unmethylated Humic Acids Extracted from Solonetz,Solod and Chernozem Ah Horizons

Humic acids were extracted from Ah horizons of a Solonetz, a Solod, and a Chernozem soil. A portion of each extracted humic acid was methylated in order to make it more resistant to attack by electrophilic KMnO₄. Both the methylated and unmethylated humic acids were then oxidized with KMnO₄. The oxidation products were extracted into ethyl acetate and separated by preparative gas chromatography into relatively pure components, which were then analyzed by mass spectrometry and micro-infrared spectrophotometry. A matching of the mass and IR spectra and gas chromatographic retention times of the isolated components with those of authentic specimens led to their identification. The most prominent compounds produced by the oxidation of methylated humic acids were 1,3,5-benzenetricarboxylic acid and a complex phenolic acid, tentatively identified as propanone-hydroxy-methyl acetoxy-benzene-dicarboxylic acid. These two compounds accounted for between 18 and 23% of the original methylated humic acids. The main products resulting from the oxidation of unmethylated humic acids were benzenetri-, benzenetetra- and benzenepenta-carboxylic acids, which constituted between 10 and 12% of the weights of the original unmethylated humic acids. The results show that methylation of humic acids prior to oxidation is a useful procedure which substantially increases the yields and types of oxidation products. From the similarities in analytical data and in the quality of the oxidation products, we conclude that the three humic acids have similar chemical structures, yielding benzenecarboxylic and phenolic acids on oxidation. These compounds either originate from more complex structures or they exist in the humic acids in the forms in which they were isolated, held together by hydrogen bonds.     

腐植酸及农药减毒增效

简述了腐植酸具有分子量大、多种官能团和酚、醌结构以及增强农药的生理活性和药理活性等基本性质,能赋予农药减毒增效的作用,并粗析药理和腐植酸胶体作用——溶胶、絮凝、表面活性、络(螯)合、吸附、稀释等。列举我国企业制订腐植酸农药(固体、液体)的企业标准。     

腐植酸从哪里来，到哪里去

从腐植酸的概念引出腐植酸的来源,从腐植酸的功能引出腐植酸的应用,从腐植酸的科研与实践引出为大环境、大农业、大工业、大医药服务的专业本色。本文通过工作实务,阐述了“腐植酸从哪里来,到哪里去”的核心价值,进一步明确了腐植酸新产业的方针、方向、机制、规模和目标,描述了腐植酸新产业的光明前景。