三元流技术在循环水泵改造中的应用

洛阳石化化纤装置循环水站的6台离心式清水泵,其叶轮是依据二元流理论设计制造的,但二元流理论并不完善,造成泵的实际运行工况偏离额定工况,同时由于存在不同程度的汽蚀现象,致使6台清水泵在较低的效率(75%～80%)下运行。为此,应用三元流技术对清水泵的叶轮进行改造:不改变电机、泵壳体、进出水管路等现有水泵系统,对叶片的进出安放角、叶片数、扭曲叶片各截面形状等进行优化设计,并采用铸焊结构进行加工制造,从而避免叶片工作面的流动分离,减少流动损失,提高叶轮的工作效率,最终达到提高水泵效率、节能降耗的目的。改造后的运行情况表明:机泵运行平稳,噪音减小,汽蚀现象明显减少,泵组效率由改造前的80%提高88.6%;改造后单台泵(流量为5000m3/h)电流降低13A,每年可节电168.48×104kW·h,节省电费67.392万元。     

发电厂循环水泵的节能改造

＠何海鸥￥江苏吴县江远热电有限公司吴县市电厂原有Ｎ１２－３５－１型机组２台，设计配用４台２０ＳＨ－１９型的循环水泵，基本运行方式为在夏天四台循环水泵刚好满足两台机组运行。由于投产后不久增加了一台３ＭＷ机组，在此机组投入后不久，因循环水温的不断升高，出现了三...     

风机水泵系统节能改造预测

风机水泵是国民经济各部门中量大面广的通用机械,在各项各业都有大量的应用,它们的耗电量在工业用电中占限大的比例,据统计,风机占发电量的 11%,泵类耗电占21%。为合理利用能源,降低电耗,有关部门对本市的水泵、风机系统进行了调研、测试、论证、改造工作。从测试的结果来看,机泵系统在产品性能、设备选型、设计施工、管路匹配、运行组合、调节方式、经济运行、检测计量、维修管理等方面都存在诸多问题。故如何使风机、水泵系统在满足工艺要求、生产安全和运行可靠的前提下,通过科学管理和技术改进,使系统中的设备、管网和负载相匹配,进行经济运行,实现投资少、电耗低是急待解决的一个问题。     

水泵、风机节能改造首选射流-尾迹三元流技术

射流-尾迹三元流动理论是著名科学家、中国科学院院士吴仲华二十世纪五十年代在美国创立的。二十世纪七十年代电子计算机得到有效应用后,这一理论被广泛应用于航空燃气轮机设计。     

多级离心式水泵节能改造

多级离心式水泵(下面简称水泵)是一种通用机械,具有较高的扬程。在国民经济的各个领域如石油化工、冶金、矿山、电力等部门都广泛使用。因而大力降低水泵的能耗,对节能具有很大的意义。本文就水泵进行的二次技术改造来讨论水泵的节能。一、概述     

600MW超临界机组凝结水泵变频改造及节能效果分析

分析变频调速的节能原理,针对工况运行凝结水泵存在节流损失大等问题,提出进行高压变频改造;介绍变频器的特点、改造方案,指出应注意的问题,并对变频改造的节能效果进行分析。     

600MW超超临界机组循环水泵双速改造

针对江苏徐州阚山电厂600 MW超超临界机组循环水泵冬季单泵运行方式循环水量富余的现状,通过循环水泵马达进行高低速改造,实现低温季节低速泵节能运行。     

应用三元流技术实施循环水系统节能改造

根据循环水泵的实际运行工况,在原来循环水系统的水泵主体、系统管路、电机等不作改动前提下,采用三元流叶轮改造技术,重新设计高效三元流叶轮,更换于原水泵叶轮,并且对水泵的过流部件进行特殊的涂层处理,优化水泵系统操作,使水泵运行效率大幅度提高,最终达到了系统节能目的。     

1000MW火电机组凝结水泵变频改造分析

玉环电厂4台1 000 MW机组投产后满负荷运行工况下除氧器水位调节阀开度在18%左右。通过对凝结水泵进行变频改造使凝结水母管压力由3.3 MPa降低至2.6MPa,调节阀开度上升到60%,削弱了节流效应,凝泵功耗下降了21%。同时,对节能原理进行了理论分析,并阐述了泵组变频改造在方案选择、调试过程、逻辑组态和运行控制等方面应该注意的一些问题,供存在类似问题的机组参考。     

藏北高原典型草甸下垫面与HEIFE沙漠区辐射平衡气候学特征对比分析

利用中日合作“全球能量与水分平衡试验一青藏高原季风试验(GAME—Tibet)”和中日合作“黑河地区地一气相互作用野外观测实验研究(HEIFE)”IOP、FOP资料,计算分析了藏北高原典型草甸下垫面安多站和HEIFE沙漠站的辐射平衡各相关特征量时频变化的气候学特征。结果表明：无论是高原安多站还是黑河沙漠站,夏季均出现超太阳常数现象(只是安多更为明显);总辐射、大气逆辐射、地表长波辐射、地表有效辐射和地表辐射平衡等的日变化(晴天)无论是安多站还是沙漠站均表现为早晚出现最小值而正午附近(地方时)达到最大值,而地表反照率的日变化(晴天)相反表现为早晚大而正午附近小的规律;上述各分量均表现有程度不等的季节变化规律：总辐射、大气逆辐射、地表长波辐射和地表辐射平衡均表现为夏半年增大达到最大值百而冬半年降低量出现最小值;另外,大气长波辐射、地表有效辐射和地表反照率在沙漠站的年际变化的振幅较安多站更为显著和有规律。     

Exploration of the land potential for the production of biomass for energy in the Netherlands

The energy potential for energy crops and biomass residues in the Netherlands is assessed. The analysis explores the possible use of land for biomass production in the future. Various government memorandums and analyses of the expected future land use in various sectors have served as the basis for the assessment of the supply of and the demand for land in the future. In this study the potential supply of agricultural land is based on expected productivity increments in agriculture and assumptions with respect to the future demand for agricultural products. Various future claims for infrastructure, forestry, urban areas and nature are subtracted from the expected supply. The net projected supply of land ranges from zero to 52 000 ha in 2000 to 110 000-250 000 ha in 2015. The supply of agricultural land depends however on a number of supra-national factors, such as the European agricultural policy, world market developments and the agricultural production in the countries in Eastern Europe. Uncertainties remain, therefore, and the projected supply of agricultural land should be considered as a possible scenario based on current trends. If the calculated land potential is used for energy crops like miscanthus and short rotation coppice, this land could contribute 0-10 PJ in 2000 and 27-59 PJ in 2015. Secondary biomass yields, such as those from forestry, agricultural residues, wood from prunings, etc., could contribute a further 34 PJ in 2000, decreasing to approximately 28 PJ in 2015. Taken together these potentials could satisfy 1-1.5% of the energy requirements of the Netherlands in 2000 and 1.5-2.5% in 2015, provided that energy farming is an economically feasible activity for farmers.     

葡萄糖在超(近)临界水/甲醇中的稳定性研究

在超(近)临界水/甲醇中分别试验考察了温度、压力、停留时间等参数对葡萄糖稳定性的影响.结果表明:无论在水中还是在甲醇中,温度越高,葡萄糖的稳定性越低,降解速率越高;降解产物5-羟甲基糠醛(HMF)和5-甲基(甲氧基)糠醛(MMF)的选择性随温度的变化存在着最大值.压力对葡萄糖在临界水中转化率的影响不明显,但在超临界甲醇中,葡萄糖的转化率随压力升高而增大,当达到临界压力以后基本不变.HMF和MMF的最大收率都出现在临界压力附近.停留时间越长,葡萄糖在超临界水和甲醇中的转化率越高,HMF的收率和选择性越低,而MMF的最大收率和最高选择性却存在着一个适宜的停留时间.     

Hydrogen in China: Policy,program and progress

The paper introduces the role of energy in China economy context, criteria for sustainable development in energy sector, China's hydrogen vision, the role of hydrogen in China's R&D plan, recently launched national programs, and progresses and achievements in research, development and demonstration. The paper concludes that with fast economy development in the new era in China, the energy sector has been confronted with severe challenges in terms of supply security, environment pollution and greenhouse gas emission, and China has attached significant priority on research and development in hydrogen and fuel cell areas, as one of effective counter-measures to address these challenges. Transition to the hydrogen economy in China, a long-term, non-carbon energy solution, is believed to play a significant role, complementary to electricity, in the future sustainable energy system. It is recommended that more priority be attached for R&D in secondary industry, especially the utilization of hydrogen and fuel cell in stationary power generation from coal gasification.     

氯对连续重整反应的影响

中国石油长庆石化公司60×10^4t／a连续重整装置采用法国AXENS公司连续重整工艺技术．催化剂采用中国石化石油化工科学研究院PS-Ⅵ型连续重整催化剂。装置在运行16个月后,出现重整反应温降逐渐减小,重整生成油辛烷值和芳烃含量下降,苯、液化气和氢产量降低,以及催化剂积炭升高等现象。引起这些现象的原因主要有重整原料性质变化,催化剂硫、氮中毒和催化剂活性下降等。经分析探讨,认为再生催化剂氯含量偏低是造成装置生产和产品质量异常的原因。对重整注氯系统进行检查后,发现再生系统注氯分配器堵塞。无法正常注氯。对再生系统注氯线进行疏通后,操作恢复正常,产品质量好转。在日常生产过程中,可通过加强DCS操作监控力度、提高氧氯化区氧含量和烧焦温度、严格控制催化剂中的氯含量和水含量等措施,保证装置平稳运行。     

A review on deposit formation in the injector of diesel engines running on biodiesel

For the short-term use of diesel engines, biodiesel can provide a comparable engine performance to that of using fossil diesel fuel. However, some arising problems including the reduction of the engine performance, the increase in lacquer deposits, and excessive carbon blacks in the combustion chamber and in the injectors resulting in an increase in the emissions and the damage to the engine have been indicated. Deposits formed inside or outside the injector may have an adverse influence on the engine performance and the fuel injection system. In this study, a review of the formed deposits in the injector of diesel engines fueled with biodiesel was conducted. The physicochemical mechanism of the deposit formation in the injector including injector nozzles, injector holes, and injector tips was mentioned. Moreover, the test-cycles for determining the deposit formation level in the injector were also introduced. Especially, the effects of the key factors such as biodiesel components, temperature, and injector configurations on the formation level of deposits were reviewed, and the utilization of the cativation mechanism in the controlling strategy of the deposits was presented. Besides, the impacts of deposits in the injector on the spray characteristics, combustion, and diesel engine operation process were also referred.     

Prospects and problems for geothermal use in agriculture in Europe

The agricultural uses of geothermal energy were the centre of attention during the initial stages of geothermal direct applications in Europe, e.g. in Hungary, Macedonia, Bulgaria, Serbia. The focus now seems to be on district heating systems, integrated systems, large balneological/tourist centres, etc. This paper analyses the problems involved in the development of agricultural uses in different regions of Europe and how this sector can be promoted. An analysis of the situation in Europe and in Hungary, Macedonia and Greece, in particular, has revealed different requirements and potentials, different combinations of influencing factors, and the need for different development strategies. It is, however, clear from this analysis that the agricultural uses of geothermal energy are not in collision with modern trends in direct geothermal developments in Europe. On the contrary, they can improve the economic aspects of any district heating or integrated system by offering excellent possibilities for cascade use of the geothermal water and combinations of users with different day/night and seasonal heat requirements.     

Variance analysis of global CO2 emission - A management accounting approach for decomposition study

In the context of the present worldwide concern and desperate search for policies to curtail carbon dioxide emission, the paper aims to determine the roles of major driving forces in aggravating emission and examine the possibility of emission cut without compromising economic growth. Variance analysis method, in the line of management accounting, is used to decompose the changes in emission of 156 sample countries over the period 1993-2007. The major findings suggest that in aggregate, rising per capita GDP has been about seven times more responsible than that of population in accentuating emission; decline in energy intensity has been instrumental in offsetting nearly half of their potential effects, while inter-fuel substitution and change in emission intensities have meager roles. However, wide disparities in structural composition of energy intensity and emission intensity of fuels among countries over the period, point towards the crucial role of proper energy management in lowering emission concomitant with high economic growth. Management accounting control, particularly variance analysis, at the national level can be an effective tool in identifying the weaknesses and exploring the areas where emission reduction can be possible.     

Introduction to the Asian Energy Security project: Project organization and methodologies

The spectacular recent economic growth in the Asia-Pacific region in general, and in many of the economies of Northeast Asia in particular, has spurred a vast expansion in the need for energy services, and an expansion in the demand for the fuels that help to supply these services. Future projections suggest that the growth of fossil fuel use in Northeast Asia, especially in China, will have major consequences for financial and fuel markets and pollution both regionally and globally. Before the project described in this paper was initiated, there was no ongoing forum for energy experts from all of the countries of the region to meet, informally and in an unofficial capacity, to discuss openly and in a targeted fashion the energy situations in their countries, and to work together to evaluate the energy efficiency costs and benefits of different ways of meeting regional demand. The Asian Energy Security (AES) project provides such a forum, and as such constitutes a unique resource in the engagement of the countries of Northeast Asia on the topic of energy security.