两级地源热泵用于天然气调压发电工艺的性能分析

本文提出了一种涡轮与两级地源热泵相耦合的新型天然气调压工艺,通过Matlab构建了系统热力学模型并借助Aspen/plus和实验数据予以验证,分析了降压和预热过程的碳排放核算方法,探究了涡轮膨胀比和热泵压缩比的最优分配策略,并结合实际案例评估了系统的经济性与环保性。结果表明：R123为热泵最优工质;热泵循环由单级升为双级后,新工艺年均(火用)效率为0.43,提升10.88%,加热效率为2.89,提升15.91%,全年净发电量3.67 GW·h,提升11.6%;相比于节流阀调压工艺,新工艺全年减少CO₂排放0.24万t,减少预热成本4.7万元,同时产生经济效益146.94万元。     

电厂循环水与热泵耦合供暖能效分析

为降低热电联产机组在集中供暖过程中的能耗,提出一种电厂循环水与热泵耦合的供暖方式,建立该采暖模式的能效计算模型,并以某350 MW超临界供热机组为例,计算该模式的能效指标。计算结果表明,在热泵制热系数4以上时,无论管网效率高低,系统供电量均增加。热泵制热系数越高,供热管网效率越低,系统供电量增加越大,相同煤耗量时最高供电功率能够达到25 MW以上。     

热泵与低真空耦合回收循环水余热的热力性能分析

基于热力学定律与分析理论,得出适用于以热泵与低真空方式回收循环水余热的热力性能分析模型,并进行计算与分析。结果表明:以额定抽汽工况为参考,3种不同供热工况的热力性能由好到差依次为:热泵供热工况、低真空供热工况、抽汽供热工况;低真空供热适合于外界热负荷较大时,而热泵供热在外界低热负荷时优势明显;热泵与低真空耦合供热时,不仅可降低初投资与机组运行风险,且具有较高的热经济性,即总热效率、总效率分别为91.16%、44.50%,节煤量达到32.69 t/h。     

300MW机组集中供生活热水改造的技术经济性分析

以某300MW亚临界燃煤供热机组为基础,结合已有吸收式热泵供热改造,进行集中制取70℃和80℃热水的技术方案分析。详细分析了系统在非采暖期、采暖初末寒期和高寒期时不同的技术经济和项目节能效益,得出结论:项目拓宽了热力市场,使得吸收式热泵在非采暖季也能投入运行,增加了电厂发电量。同时,制取70℃热水的项目净收益大于80℃的收益,投资回收期也较短。在用户热水需求4000t/d的情况下,制取70℃生活热水可实现节煤1.28万t,制取80℃生活热水累计可节煤1.51万t,项目具有较好的节能减排效果。     

计及碳交易和碳税的碳捕集技术经济性研究

采用经济学成本分析法对集成碳捕集封存技术(CCS)的1 000 MW超超临界燃煤机组进行技术经济性分析,以供电成本、净现值、动态回收期及内部收益率为评价指标,探究了煤炭价格、碳配额交易价格、碳税、通货膨胀率及CO₂售卖价格的影响。结果表明：CCS碳捕集装置建设成本较高,较常规机组总投资增加约24.54%,CCS系统能效惩罚较大,厂用电率增加19.31百分点;常规机组供电成本为0.307 5元/(kW·h),CCS机组的供电成本增加35.87%;CO₂减排成本为171.47元/t; CCS机组净现值为138.06亿元,为常规机组的2.23倍;CCS机组的动态回收期为4.15 a,较常规机组提前1.94 a;综合考虑碳税、碳配额交易及CO₂售卖时,CCS机组的供电成本为0.196 4元/(kW·h),较常规机组低43.17%;在碳交易、碳税政策和CO₂循环再利用市场完善建立后,CCS机组具有更强的盈利能力。     

热泵回收电厂循环水余热预热凝结水的经济性分析

针对汽轮机排汽造成大量余热浪费以及一定量循环水损失的问题,基于热泵余热回收再利用技术,利用吸收式热泵系统取代8号加热器的抽汽,建立了热泵回收循环水余热来预热凝结水的物理模型和数学模型。以N300-16.67/537/537机组为例,对机组进行了经济性分析和计算。结果表明,系统改造后年增加收益为160.7万元,4年内可回收投资,净现值(NPV)指标为738,具有良好的经济效益与环境效益,为以后火电机组余热回收的研究提供了参考。     

回收循环水余热的热泵供热系统经济性分析

利用热泵技术回收电厂循环水余热,能够提高机组的热效率和供热能力,降低机组的冷源损失。从热泵制热性能系数COP出发,分析压缩式和溴化锂吸收式热泵的节能机理,并以300MW机组为例,在保证供热负荷不变的情况下,计算分析2种热泵供热系统的经济性。计算结果表明:溴化锂吸收式热泵供热机组的经济性优于压缩式热泵机组,整个供暖期间,获得的总节能收益比压缩式热泵供热机组高785.8万元。在乏汽利用方面,压缩式热泵供热机组的节水量要远高于溴化锂吸收式热泵供热机组,这对于某些缺水地区有重要意义。     

背压影响热泵回收循环水余热的试验研究

通过对利用热泵回收循环水余热的热电厂进行性能试验,并进行了数据处理与分析。结果表明:热泵运行时存在最佳的机组背压,其最佳背压受机组低压缸排汽量和外界热负荷的影响较大;一般情况下,增大余热回收量在一定程度上可以增强热泵系统的性能;当机组的排汽量较小时,机组背压对机组整体的能耗影响较小,可通过提高机组背压来增加余热回收量。     

CO_2跨临界热泵和加热炉冷却循环耦合系统性能分析

提出跨临界CO2热泵和朗肯循环耦合实现加热炉的余热回收。基于热力学研究方法,分别对影响耦合循环效率和CO2跨临界热泵性能的关键参数进行了研究。随着热泵性能COP的提高,耦合循环的效率提高。当热泵性能超过限定值后,压缩机耗功比值越大,耦合循环效率越低。排气压力范围内,热泵性能和耦合循环效率均有极值。给定条件下最优排气压力为8.5 MPa,热泵性能COP为4.2,耦合循环效率为0.35。蒸发温度提高或冷凝温度降低,均有利于热泵性能和耦合循环效率的提高。此研究为回收加热炉余热和提高电厂效率提供理论基础。     

太阳能联合热泵型煤干燥系统设计

为了减少污染降低成本,设计了一套太阳能空气集热器、空气源热泵和热泵蒸汽机组联合干燥系统。通过实验测试和热量衡算后,拟采用400 m~2的空气集热器、8台空气源热泵和3台蒸汽热泵机组即可满足型煤干燥需求。预计改造费用约236万元,投资回收期2.7年;成本由35元/t降低为21.6元/t;年节约标煤2 660 t以上,减排CO_2约6 916 t,减排SO_2约63.84 t,减排NO_x约18.62 t,改造后具有较好的经济效益和环境效益。     

小型锅炉烟尘测试时锅炉出力的计算

锅炉烟尘测试时,必须对锅炉出力进行测试。但监测中,许多小型锅炉往往不具备相关的计量装置和仪表,为解决这一问题,文章提出了用烟气量和空气过剩系数来计算锅炉的出力的公式,在实际使用中,该方法简单易行,其结果和实测值具有很好的一致怀。     

Unerroric of control of mutual compliance of the efficiency of hydrogen engines of unmanned vehicles in the conditions of mass production

The issues related to the reliability of hydrogen engines of unmanned vehicles and increasing the efficiency of using hydrogen as fuel when using the method of its production during the decomposition of hydrogen-containing molecules of liquid-phase organic compounds in a plasma discharge under the action of intense ultrasonic exposure are considered. Experiments have shown that as a result of decomposition in the acoustoplasma discharge of liquid hydrocarbons, solid-phase carbon-containing products are formed, chemical transformations occur in the liquid phase and hydrogen-containing combustible gas is formed. Hydrogen-containing gas can be used as fuel immediately after synthesis, i.e. it does not require separation, since in addition to hydrogen it contains only impurities of CO₂ and water vapor. The purpose of the study is to formalize the basic conditions for tightening the control of mutual compliance with the efficiency of hydrogen engines of the same series in the conditions of their mass production. Methods of mathematical statistics and hardware-software modeling were used in the study. The term “unerroric of quality mutual compliance control” is introduced to describe a set of hardware and software tools for such control. The principle of in-depth testing of the technical condition of such engines of one series is described in a multidimensional formulation of the quality control problem for three of their operating parameters at once. The conditions for increasing the mutual correspondence of the measured values of such parameters in the conditions of serial production of hydrogen engines are formalized.     

中国煤炭地下气化技术的发展

本文综述了煤炭地下汽化技术的国内外发展现状,对我国“长通道、大断面”煤炭地下气化新工艺给予了技术经济评述,并提出了发展煤炭地下汽化技术的政策建议。     

Review of theory of distortion and disintegration of liquid streams

Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined.     

机车车轮多轴疲劳强度安全评定的研究

使用ANSYS8.0软件对高速列车车轮进行了三维有限元分析,计算出车轮在直线、曲线和道岔条件下牵引、制动共6种工况时孔边薄弱部位的应力,分别通过Mises等效平均应力方法、Sines平均主应力方法和应力分量中考虑平均应力方法计算出应力在极值位置时的等效应力幅、等效平均应力,从而进一步算出车轮的安全系数,对其疲劳强度进行评定,并对3种方法进行了比较研究。     

Constructal optimization of the geometry of an array of micro-channels

This paper documents the geometric optimization of an array of circular and non-circular ducts. The optimization was carried out numerically using finite volume method. As optimal dimensions were independent of the array configuration, the numerical simulation was performed on a unit cell. Numerical optimization for circular, square and isosceles right triangle cross-sections of channels was performed. Based on the results of this investigation, some correlations were proposed to predict the optimal hydraulic diameter and dimensionless heat transfer per unit volume. In addition to examining the effect of pressure drop on these parameters, it was showed that among the different geometries of this study, square cross-section has the most efficiency for a given volume. The numerical results of the present study were compared with approximate results reported in the literature which a good agreement was observed.     

MgO膨胀剂细度对MgO水化和水泥浆体膨胀的影响

基于《水工混凝土掺用氧化镁技术规范》中的Ⅰ型氧化镁（MgO）,研究了该型MgO膨胀剂（MEA）细度对掺粉煤灰水泥浆体膨胀性能的影响。即采用X射线衍射分析(XRD)及同步热分析（TG DSC）分析了掺MEA水泥浆体中MgO的水化性。结果表明,养护温度相同时,MEA的细度对水泥浆体内MEA中MgO的水化和水泥浆体的膨胀无显著影响,产生的膨胀均能补偿水泥浆体的收缩;MEA的细度可从试验设计采用的45 μm筛筛余15%左右增加到30%左右,这将有利于MEA生产企业的节能降耗。     

固体热辐射Yong性能分析

本文对漫灰均温物体在常物性条件下对外辐射传热的Ｙｏｎｇ值计算建立了数学模型。通过与物体内能Ｙｏｎｇ公式的数值计算比较,得出了辐射能量的Ｙｏｎｇ值不大于内能Ｙｏｎｇ值的结论。从初步的热射Ｙｏｎｇ值计算公式发现。Ｙｏｎｇ与物体表面辐射率有关。     

Measurements of concentration distribution of hydrogen jet using deflection of center of the laser spot

The main purpose of this work is to propose a new method to evaluate the concentration distribution of the hydrogen jet by using a He–Ne laser through the jet. This research attempts to apply the expression of concentration Gaussian distribution, the refraction formula of inhomogeneous refractive index medium, and the concentration inversion function to disclose the displacement of the center of the laser spot at different heights in the gas jet. The spot images of the laser beam passing through the gas jet at three vertical heights z = 10d, 20d, 30d, and different radial positions are obtained. The radial spatial asymmetry of the gas jet is also found in the experiment. Finally, the calculated concentration distribution curve and the fluent simulation curve, it is found that the two results are very similar. Our findings show that the error between the concentration distribution of this method and the simulated concentration distribution reaches 2.43%.     

汽轮机零件防锈性能的改善

介绍了汽轮机零件的封存特点、防锈要求及防锈油性能对比试验的方法,通过对试验结果的对比分析,客观验证了各种防锈油的性能。试验表明,只有选择了合适的防锈油,才能保证汽轮机零件长期封存的质量。