国产200MW机组结构特性与油膜振荡

木文扼要分析了200MW机组油膜振荡与轴系、轴承、轴承座结构特性的关系,说明一阶临界转速和轴承失稳转速偏低存在油膜振荡的可能性,并根据油膜振荡机理说明转子动平衡、转子对中、轴承找中心必需提高精度才能避免油膜振荡。并提出将轴承失稳转速提高到额定转速的125％以上,消除油膜振荡的可能性,还说明将三油楔轴承改为椭圆轴承是比较现实的措施,但也有一些问题需要试验研究。本文还提出轴系临界转速偏低、偏多和分布不合理的问题,升速和超速试验时要注意避免共振和油腹振荡.要准确测定各阶临界转速、提高操作水平严防共振和振荡。     

半山1号燃气机组油膜涡动和油膜振荡分析及处理

对9F单轴式燃机发生在可倾瓦轴承上的油膜涡动和油膜振荡进行了介绍、分析和诊断。给出了引起汽机高中压转子油膜振荡的定性原因分析,提出了增大油孔、减少轴承宽度的处理措施,油膜振荡故障得到消除。     

转子系统油膜涡动及油膜振荡故障特征分析

介绍了转子系统油膜涡动及油膜振荡的产生机理和故障特征。对转子实验台升速过程的振动信号进行了分析,揭示了转子系统油膜涡动和油膜振荡的发生过程。对典型油膜涡动和油膜振荡信号进行了时频分析,揭示出油膜涡动和油膜振荡的故障特征。     

200MW机组油膜振荡产生原因及消除措施

从安装调试角度分析了200MW机组油膜振荡产生的原因及应采取的措施。指出提高设备制造和安装质量是应前避免大机组产生油膜振荡的重要途径。     

国产200MW汽轮发电机组油膜振荡的现场测试与分析

本文给出3台国产200MW汽轮发电机组发生油膜振荡的实例,分析了发生油膜振荡时所呈现的振动特征.讨论了轴承非线性油膜力对振动的影响,低频振动分量与轴瓦稳定性的关系,以以转子平衡状况与油膜振荡的关系.图4参4     

汽轮发电机组油膜振荡故障诊断和现场处理

介绍了汽轮发电机组油膜振荡产生的机理以及振动信号的特征,并结合现场启机过程中发生油膜振荡的情况,给出了现场油膜振荡故障振动特征信号及诊断处理方法。     

分宜电厂6号机振动原因分析和处理

本文以分宜电厂6号机振动事故的处理为例,分析了发电机冷却水路堵塞和汽机转子中心进入液体而引起振动的机理和振动特征.并对导致机组油膜振荡的原因进行了分析.     

汽轮发电机组轴系--支撑系统油膜失稳问题探讨

将油膜涡动归为汽轮发电机组轴系－支撑系统的固有振动,讨论了影响油膜稳定性的因素,并给出了消除油膜失稳的措施     

300 MW机组汽轮机轴瓦油膜振荡分析与处理

天津华能杨柳青热电有限责任公司8号机组汽轮机运行中3号轴瓦发生故障,通过分析轴瓦Y向振动趋势图、轴承Y向振动异常点频谱图,确定振动原因为油膜激振。分析出现故障的原因为轴承间隙配合超标、轴瓦压比小、轴瓦载荷分布不合理等。并采取调整轴瓦压比、减小轴瓦顶隙、调整轴瓦标高等手段来提高轴瓦稳定性,进而消除油膜振荡的隐患。     

线性与非线性油膜力模型下转子振动稳定性对比研究

滑动轴承的油膜力直接影响转子振动的稳定性,首次对大型多自由度转子系统在线性和非线性油膜力作用下的振动稳定性进行了对比分析。针对200Mw汽轮机低压转子一轴承系统,采用数值计算方法分别模拟了转子在非线性油膜力和传统的8个刚度和阻尼系数表示的线性油膜力模型下,转子升速过程中发生油膜失稳的典型特征。通过比较分析得出考虑油膜力的非线性特性后转子发生油膜振荡的转速提前。因此为保证大型转子-轴承系统的安全稳定运行,有必要在传统线性理论设计的基础上,引入非线性油膜力形式对系统的稳定性作进一步的计算校验。     

我国经济和社会发展中必须重视石油峰值问题

石油峰值(Peak Oil)是指某一区域(全球、地区、国家、油区等)石油产量的最大值及其来临的时间。世界石油产量到达峰值并不意味着全世界已将石油消耗怠尽,也不意味着人类不可能在地球上再发现新的油田,只是新发现的油田的石油产量越来越无法弥补已开发油田产量的下降,世界石油供应量不可能再增加,不能满足人类日益增长的需求。许多研究表明世界石油产量正在进入峰值平台期,随时都可能出现资源长期短缺的石油危机。我国的石油消费一直以较快的速度增长,石油也许很快成为我国经济发展的瓶颈。本文提出了石油峰值——我国经济和社会发展中必须重视的一个重大问题,希望大家尤其是主管部门和高层决策者充分认识石油峰值的内涵和挑战,高度重视我国面临的潜在的石油危机,认真落实科学发展观、未雨绸缪,提早采取应对策略以实现我国经济社会的可持续发展。     

美国战略石油储备补仓和释放策略分析

美国是最早建立战略石油储备的国家之一,自20世纪70年代开始已逐步形成了一套比较完善的战略石油储备决策管理体系。历史数据表明,美国战略石油储备的几次释放和补仓时机都把握得很好,充分发挥了战略石油储备保障国家石油供应安全、平抑国际原油价格的作用。本文系统地介绍和分析了美国战略石油储备几次主要的释放和补仓策略,以期为探讨我国战略石油储备的补仓和释放时机与策略,提供决策信息参考。     

开发难动用储量保障国家石油安全

保障我国石油安全有多种措施：建立石油储备、发展替代能源、降低能耗、从国外获取稳定的石油供应、加大国内石油资源的勘探开发力度等。其中，加强国内石油资源的勘探开发是最重要的途径。本文针对我国陆上近４０亿ｔ已探明难动用石油地质储量的现实，从国家石油政策、技术进步、开发方式和机制、评价方法和参数等方面论述了促进难动用储量开发，保障国家石油安全的途径。     

我国急需发展石油期货市场

本文从我国石油需求逐年上升、对进口依赖性不断提高以及国际石油市场起伏不定的现实出发,分析论述了我国发展石油期货市场的必要性和可行性,并提出了发展石油期货市场方面的建议。     

Mitigation of maximum world oil production: Shortage scenarios

A framework is developed for planning the mitigation of the oil shortages that will be caused by world oil production reaching a maximum and going into decline. To estimate potential economic impacts, a reasonable relationship between percent decline in world oil supply and percent decline in world GDP was determined to be roughly 1:1. As a limiting case for decline rates, giant fields were examined. Actual oil production from Europe and North America indicated significant periods of relatively flat oil production (plateaus). However, before entering its plateau period, North American oil production went through a sharp peak and steep decline. Examination of a number of future world oil production forecasts showed multi-year rollover/roll-down periods, which represent pseudoplateaus. Consideration of resource nationalism posits an Oil Exporter Withholding Scenario, which could potentially overwhelm all other considerations. Three scenarios for mitigation planning resulted from this analysis: (1) A Best Case, where maximum world oil production is followed by a multi-year plateau before the onset of a monatomic decline rate of 2–5% per year; (2) A Middling Case, where world oil production reaches a maximum, after which it drops into a long-term, 2–5% monotonic annual decline; and finally (3) A Worst Case, where the sharp peak of the Middling Case is degraded by oil exporter withholding, leading to world oil shortages growing potentially more rapidly than 2–5% per year, creating the most dire world economic impacts.     

Feasibility of edible oil vs. non-edible oil vs. waste edible oil as biodiesel feedstock

Biodiesel has high potential as a new and renewable energy source in the future, as a substitution fuel for petroleum-derived diesel and can be used in existing diesel engine without modification. Currently, more than 95% of the world biodiesel is produced from edible oil which is easily available on large scale from the agricultural industry. However, continuous and large-scale production of biodiesel from edible oil without proper planning may cause negative impact to the world, such as depletion of food supply leading to economic imbalance. A possible solution to overcome this problem is to use non-edible oil or waste edible oil (WEO). In this context, the next question that comes in mind would be if the use of non-edible oil overcomes the short-comings of using edible oil. Apart from that, if WEO were to be used, is it sufficient to meet the demand of biodiesel. All these issues will be addressed in this paper by discussing the advantages and disadvantages of using edible oil vs. non-edible vs. WEO as feedstock for biodiesel production. The discussion will cover various aspects ranging from oil composition, oil yield, economics, cultivation requirements, land availability and also the resources availability. Finally, a proposed solution will be presented.     

Performance and emission characteristics of a DI compression ignition engine operated on Honge, Jatropha and sesame oil methyl esters

The high viscosity of vegetable oils leads to problem in pumping and spray characteristics. The inefficient mixing of vegetable oils with air contributes to incomplete combustion. The best way to use vegetable oils as fuel in compression ignition (CI) engines is to convert it into biodiesel. Biodiesel is a methyl or ethyl ester of fatty acids made from vegetable oils (both edible and non-edible) and animal fat. The main resources for biodiesel production can be non-edible oils obtained from plant species such as Pongamia pinnata (Honge oil), Jatropha curcas (Ratanjyot), Hevea brasiliensis (Rubber) and Calophyllum inophyllum (Nagchampa). Biodiesel can be used in its pure form or can be blended with diesel to form different blends. It can be used in CI engines with very little or no engine modifications. This is because it has properties similar to mineral diesel. This paper presents the results of investigations carried out on a single-cylinder, four-stroke, direct-injection, CI engine operated with methyl esters of Honge oil, Jatropha oil and sesame oil. Comparative measures of brake thermal efficiency, smoke opacity, HC, CO, NO_X, ignition delay, combustion duration and heat release rates have been presented and discussed. Engine performance in terms of higher brake thermal efficiency and lower emissions (HC, CO, NO_X) with sesame oil methyl ester operation was observed compared to methyl esters of Honge and Jatropha oil operation.     

Factors Affecting the Oil Agglomeration of Sivas-Divriği Uluçayır Lignite

Abstract

In the coal industry, the coal particles need to be decreased to a very fine size because of the need of removing inorganic materials from coal. Oil agglomeration is a kind of coal cleaning technique that is used for separation of organic and inorganic parts of fine sized coal. In this study, the oil agglomeration of Sivas-Divri?i (S-D) Uluçay?r lignite was carried out by using kerosene, diesel oil, fuel oil, poppy oil, and sunflower oil. The amount of bridging oil was varied from 5% to 25% of the amount of lignite. The effect of oil amount, oil type, solid content, agitation rate and time, pH on agglomeration performance was investigated. Maximum recovery value of 98.18% was observed by using poppy oil. In order to investigate the effect of pH on agglomeration NaOH and HCl is added to the slurry in various amounts. It is decided that the best agglomeration condition is obtained at low pH values. The effect of nonionic surface active agent (Igepal-CA 630) on agglomeration is investigated by adding to the slurry and it is observed that the grade is increased with the amount of surface active agent.     

对燃油锅炉渣油供油系统的工艺改进

针对渣油特性及其应用过程中易发生的问题,介绍了供油系统的几项有效改进措施。     

近期石油市场供需形势分析

5月份受SARS疫情影响,国内石油消费需求下降;另一方面,5月以来石油资源增势有所回落,原油及成品油的增幅较之1季度均有不同程度减缓,又加之受国际行情下挫等诸多因素的共同作用,使得国内持续走高的油价大幅下跌。在多方面力量推动下,进入6月以来上述情况有所缓解。通过对近期国内外经济走势的综合分析,认为随着SARS疫情得到有效控制,国内各油品市场油品销售将会有不同程度的提高,市场后期形势趋于回升。