蒸气动力系统的运行优化研究与应用

针对配备蒸气动力系统的工业企业,总结了企业现有调度经验并将其融入理论研究过程,建立了蒸气动力系统的调度优化模型。参考实际运行参数,建立锅炉、汽机等设备模型。利用非线性规划方法对系统进行求解,得到最优操作参数即最优运行方案。应用实例表明,该优化调度方案具有很强的经济性与可操作性。结合优化调度技术,可指导企业根据已积累的调度模式与经验对蒸气动力系统进行科学调度。该方案不仅提高了优化调度水平,而且能提升节能效益、有效降低企业的生产与调度成本。

高效蒸气动力装置

力装置,该装置使用气凝聚、液化丙烷、甲醇、煤油、低质汽油等作为燃料。它与内燃机不同的是,并不燃烧燃料,而是使燃料进行化学氧化,通过此时发生的热来过热高压的工作液体,当把这种过热液体的一部分喷射到气缸内时,即变成为蒸气,其压力燃料,故不会排放一氧化碳及氮氧化物污染空气,它排出的是水和二氧化碳。把蒸气动力装置装备在汽车上,不再需要齿轮箱、离合器、凸轮轴、点火装置以及起动装置等。它不仅可以用于轿车、卡车,还能广泛用于拖拉机、联合收割机以及船舶等方面。

舰船蒸汽动力装置热线图分析

本文分析计算了某舰船蒸汽动力装置单元的系统■效率和各设备单元的■效率及其■损系数。和陆上蒸汽动力系统一样，舰船锅炉是蒸气动力系统■损失最大的部位。分析表明，在舰船具体条件下，适当布置烟道尾部受热面并采用主机一级撤汽补充低压汽网，对提高系统■效率有所助益。

基于Labview的不确定环境下化工厂蒸汽动力系统多目标建模与实时操作优化

针对化工厂蒸汽动力系统运行时操作单元蒸汽供需在不确定的时间以不确定的组合形式变化而造成的难以进行实时操作优化的问题,建立了多目标非线性混合整数滚动规划模型(MO-MINLP),并提出以Labview软件为集成平台,利用其数据采集与处理模块实现对蒸汽动力系统操作运行数据的实时采集与处理;按照实时采集的描述不确定事件开始与结束的时刻划分滚动优化周期的时间间隔长度。利用上述方法对某真实化工厂的蒸汽动力系统的数据进行仿真,并实时将多目标优化决策结果以图形化的形式显示在Labview界面上。仿真结果表明,此方法很好地解决了理论与工业衔接的问题,具有良好的应用价值。

巴基斯坦Lakhra和Thar褐煤半焦的水蒸气催化气化(英文)

采用热重法在常压与700℃～900℃条件下的水蒸气气化过程，对两种巴基斯坦Lakhra和Thar褐煤半焦进行了单一和混合催化剂（即3％钙和5％钠-黑液单一催化剂及一种3％钙和5％钠-黑液混合催化剂）对碳转化率、气化反应速率常数及活化能、有害污染含硫气体相对量的催化效应研究。两者Lakhra和Thar褐煤半焦经直接气化就可获得高的碳转化率，但采用纸浆黑液催化剂可使气化速率变得很快。含灰高的Thar褐煤半焦在纸浆黑液催化气化过程更易生成一些复杂的硅酸盐，从而导致比含灰低的Lakhra褐煤半焦出现一个更低的转化率。在水蒸气气化过程由半焦和纸浆黑液自身所产生的SO2和H2S含硫气体可为存在于纸浆黑液中的Ca盐所捕获而完成脱硫过程，但这一过程在低于900℃时更有效。缩芯模型（SCM）可较好地用来关联转化率与时间的关系并给出不同温度下的反应速率常数矗。基于阿累尼乌斯方程预测了反应活化能Ea和指前因子A。在纸浆黑液和钙混合催化及纸浆黑液催化剂时，Lakhra褐煤半焦的Ea分别为44．7kJ／mol和59．6kJ／mol明显小于Thar褐煤半焦的Ea=114．6kJ/mol和Ea=100．8kJ／mol，同样也小于无催化剂纯半焦气化时Lakhra褐煤半焦的Ea=161．2kJ/mol和Thar半焦的Ea=124．8kJ／mol。

提高车用发动机能量利用率研究进展

描述了近几年车用汽油机发展的几种新技术,包括GDI和HCCI燃烧技术以及混合动力技术的应用和发展,分析了它们的特点和在节能、环保等方面的作用。介绍了利用发动机排气余热的温差发电技术。论述了利用发动机冷却水余热和排气余热来改善发动机性能的新技术,该技术通过一套发动机后接蒸气动力装置,回收发动机余热能量做功,从而提高发动机能量利用率。探讨了这一新技术的研究内容,展望了它的应用发展前景。

热电冷联产系统的探讨

介绍了热电联产的发展,论述了热电联产系统的特点,分析了外燃烧式热电冷联产系统节能条件,计算表明内燃烧式系统具有节能优势和潜力。

所谓四次产业革命

最近国际上议论所谓“新的世界产业革命”问题,在报刊上发表了很多文章,又有一些著作出版,有的叫“第四次产业革命”或叫“第四次工业革命”。大体上时间划分和它的内容是: 第一次产业革命。第一次产业革命开始是十八世纪六、七十年代,首先从英国开始,随后发展到法国、德国、美国、俄国、日本等主要资本主义国家。这次产业革命的技术核心和技术标志是在生产中采用蒸气机和工具机,尤其是其中蒸气机。

沈士灵——川籍华人开发北婆罗洲的先驱

谈到华侨开发南洋,两广、福建籍华侨人数占绝大部分,功绩至为显著,而川籍华侨却屈指可数,本文提到的沈士灵先生则可堪称为川籍华侨开发北婆罗洲的先驱,而其史迹却鲜为人知。 沈士灵原籍四川忠县,生于1900年9月。18岁中学毕业后,拟留学日本攻读政法。当乘“蜀享”轮船时,惊奇于蒸气动力机械操纵航驶的灵活,继而见汉口、南京、上海等地工商都市建设的发达,顿悟时代剧变。

试谈煤炭洗选加工的宏观经济效益问题

在煤炭洗选加工中应用宏观经济观点进行实际分析、计算是涉及广泛而异常复杂的问题,但是只要能超出煤矿企业的范围、更广泛的从整个国民经济角度来探讨经济效果问题是可以在一定程度上实现的。其基本方法是把煤炭产品按照用户使用后生产出最终产品(如钢铁、电力及蒸气动力等)的深度去计算就能在很大程度上体现出宏观经济效果来。

Kinetic model on coke oven gas with steam reforming

The effects of factors such as the molar ratio of H2O to CH4 (n(H2O)/n(CH4)), methane conversion temperature and time on methane conversion rate were investigated to build kinetic model for reforming of coke-oven gas with steam. The results of experiments show that the optimal conditions for methane conversion are that the molar ratio of H2O to CH4 varies from 1.1 to 1.3 and the conversion temperature varies from 1 223 to 1 273 K. The methane conversion rate is more than 95% when the molar ratio of H2O to CH4 is 1.2, the conversion temperature is above 1 223 K and the conversion time is longer than 0.75 s. Kinetic model of methane conversion was proposed. All results demonstrate that the calculated values by the kinetic model accord with the experimental data well, and the error is less than 1.5%.

Dealumination kinetics of composite ZSM-5/mordenite zeolite during steam treatment: An in-situ DRIFTS study

To get a better understanding of structural deactivation of ZSM-5/MOR during the catalytic cracking of n-heptane in the steam atmosphere, a comprehensive mechanism of hydrothermal dealumination was proposed through in-situ diffuse reflectance Fourier transform infrared spectroscopy(DRIFTS) in this work. The mechanism can be divided into two steps: firstly, the hydrolysis of four Al\\O bonds, and secondly, the self-healing of Si\\OH bonds accompanied with partial condensation of the extra-framework Al species. Accordingly, the kinetics of dealumination process has also been fully discussed. In the IR spectra, the range of 3450–3850 cm^(-1) could be deconvolved to distinguish the hydroxyl groups on the different position and calculate the consumption of each hydroxyl group during the reaction. Based on results from the in-situ DRIFTS, the kinetics of dealumination was hence developed and also in well agreement with the kinetics of deactivation of ZSM/MOR catalysts during the reaction in the presence of little coke deposits.

Configuration Consideration for Expander in Transcritical Carbon Dioxide Two-Stage Compression Cycle

To investigate the configuration consideration of expander in transcritical carbon dioxide two-stage compression cycle, the best place in the cycle should be searched for to reinvest the recovery work so as to improve the system efficiency. The expander and the compressor are connected to the same shaft and integrated into one unit, with the latter being driven by the former, thus the transfer loss and leakage loss can be decreased greatly. In these systems, the expander can be either connected with the first stage compressor (shortened as DCDL cycle) or the second stage compressor (shortened as DCDH cycle), but the two configuration ways can get different performances. By setting up theoretical model for two kinds of expander configuration ways in the transcritical carbon dioxide two-stage compression cycle, the first and the second laws of thermodynamics are used to analyze the coefficient of performance, exergy efficiency, inter-stage pressure, discharge temperature and exergy losses of each component for the two cycles. From the model results, the performance of DCDH cycle is better than that of DCDL cycle. The analysis results are indispensable to providing a theoretical basis for practical design and operating.

Investigation of Calcium Sulfide Regeneration with Steam

Harmless treatment of CaS from coal gas desusulfurization and other industries is of very importance for the environmental protection. In this paper, the experimental investigation of calcium sulfide regeneration with steam at atmospheric pressure was carded out using TGA, fixed bed reactor and SEM-EDX analysis. The results show that the reaction mechanism of CaS with steam varies with temperature. The reaction occurs obviously at the temperature above 630℃ and the dominant products include CaSO4 （or CaSO3） and H2S, as the temperature is over 850℃, the primary products become CaO, SO2 and H2S. The CaS regeneration reaction will strongly depend on the temperature and the data over 900℃ can be fitted by the Shrinking-Core Model （SCM）.

Kinetics of Vapor-Phase Carbonylation of Ethanol on Ni-Zn/C Catalyst

A novel heterogeneous Ni-Zn/C catalyst was used for vapor-phasecarbonylation of ethanol under at- mospheric pressure. Experimentswere designed with the elimination of mass-transfer resistances. Thedata of primary reactions in the carbonylation were collected with adifferential tubular reactor. Power law rate models were employed toexpress the conversion of ethanol and the yields of ethyl propionateand diethyl ether. The results obtained with the models were inagreement with the experimental data.

The Effect of Micro Air Movement on the Heat and Moisture Characteristics of Building Constructions

The research focuses on the effect of air movement through building constructions. Although the typical air movement inside building constructions is quite small （velocity is of order -10-5 m/s）, this research shows the impact on the heat and moisture characteristics. The paper presents a case study on the modeling and simulation of 2D heat and moisture transport with and without air movement for a building construction using a state-of-art multiphysics FEM software tool. Most other heat and moisture related models don＇t include airflow or use a steady airflow through the construction during the simulation period. However, in this model, the wind induced pressure is dynamic and thus also the airflow through the construction is dynamic. For this particular case study, the results indicate that at the intemal surface, the vapor pressure is almost not influenced by both the 2D effect and the wind speed. The temperatures at the inner surface are mostly influenced by the 2D effect. Only at wind pressure differences above 30 Pa, the airflow has a significant effect. At the extemal surface, the temperatttres are not influenced by both the 2D effect and the wind speed. However, the vapor pressure seems to be quite dependent on the wind induced pressure. Overall it is concluded that air movement through building materials seems to have a significant impact on the heat and moisture characteristics. In order to verify this statement and validate the models, new in-depth experiments including air flow through materials are recommended.

Dynamic behaviors of cavitation bubble for the steady cavitating flow

In this paper, by introducing the flow velocity item into the classical Rayleigh-Plesset dynamic equation, a newequation, which does not involve the time term and can describe the motion of cavitation bubble in the steadycavitating flow, has been obtained. By solving the new motion equation using Runge-Kutta fourth order methodwith adaptive step size control, the dynamic behaviors of cavitation bubble driven by the varying pressure fielddownstream of a venturi cavitation reactor are numerically simulated. The effects of liquid temperature (correspondingto the saturated vapor pressure of liquid), cavitation number and inlet pressure of venturi on radial motionof bubble and pressure pulse due to the radial motion are analyzed and discussed in detail. Some dynamicbehaviors of bubble different from those in previous papers are displayed. In addition, the internal relationshipbetween bubble dynamics and process intensification is also discussed. The simulation results reported in thiswork reveal the variation laws of cavitation intensity with the flow conditions of liquid, and will lay a foundationfor the practical application of hydrodynamic cavitation technology.

Eddy covariance measurements of water vapor and CO_2 fluxes above the Erhai Lake

Measurement of turbulence fluxes were performed over the Erhai Lake using eddy covariance(EC) method.Basic physical parameters in the lake-air interaction processes,such as surface albedo of the lake,aerodynamic roughness length,bulk transfer coefficients,etc.,were investigated using the EC data in 2012.The characteristics of turbulence fluxes over the lake including momentum flux,sensible heat flux,latent heat flux,and CO2 flux,and their controlling factors were analyzed.The total annual evaporation of the lake was also estimated based on the artificial neural network(ANN) gap-filling technique.Results showed that the total annual evaporation in 2012 was 1165 ± 15 mm,which was larger than the annual precipitation(818 mm).Local circulation between the lake and the surrounding land was found to be significant throughout the year due to the land-lake breeze or the mountain-valley breeze in this area.The prevailing winds of southeasterly and northwesterly were observed throughout the year.The sensible heat flux over this plateau lake usually had a few tens of W m-2,and generally became negative in the afternoon,indicating that heat was transferred from the lake to the atmosphere.The sensible heat flux was governed by the lake-air temperature difference and had its maximum in the early morning.The diurnal variation of the latent heat flux was controlled by vapor pressure deficit with a peak in the afternoon.The latent heat flux was dominant in the partition of available energy in daytime over this lake.The lake acted as a weak CO2 source to the atmosphere except for the midday of summer.Seasonal variations of surface albedo over the lake were related to the solar elevation angle and opacity of the water.Furthermore,compared with the observation data,the surface albedo estimated by CLM4-LISSS model was underestimated in winter and overestimated in summer.

Optimization of Root Section for Ultra-long Steam Turbine Rotor Blade

This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Math number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements （optical and pneumatic）.

Development of a soil-plant-atmosphere continuum model (HDS-SPAC) based on hybrid dual-source approach and its verification in wheat field

HDS-SPAC,a new soil-plant-atmosphere continuum(SPAC) model,is developed for simulating water and heat transfer in SPAC.The model adopts a recently proposed hybrid dual source approach for soil evaporation and plant transpiration partitioning.For the above-ground part,a layer approach is used to partition available energy and calculate aerodynamic resistances,while a patch approach is used to derive sensible heat and latent heat fluxes from the two sources(soil and vegetation).For the below-ground part,soil water and heat dynamics are described by the mixed form of Richards equation,and the soil heat conductivity equation,respectively.These two parts are coupled through ground heat flux for energy transfer,root-zone water potential-dependent stomatal resistance,and surface soil water potential-dependent evaporation for water transfer.Evaporation is calculated from the water potential gradient at soil-atmosphere interface and aerodynamic resistance,and transpiration is determined using a Jarvis-type function linking soil water availability and atmospheric conditions.Some other processes,such as canopy interception and deep percolation,are also considered in the HDS-SPAC model.The hybrid dual-source approach allows HDS-SPAC to simulate heat and water transfer in an ecosystem with a large range of vegetation cover change temporally or spatially.The model was tested with observations at a wheat field in North China Plain over a time of three months covering both wet and dry conditions.The fractional crop covers change from 30% to over 90%.The results indicated that the HDS-SPAC model can estimate actual evaporation and transpiration partitioning and soil water content and temperature over the whole range of tested vegetation coverage.