高蒸发强度的锅内装置——17吨/时列车电站锅炉锅内装置的改进

17吨/时列车电站锅炉由于受到列车结构的限制,只能采用φ1000毫米(内径)长度为4000毫米的汽包。原锅内装置设计过分简单,蒸汽品质均不合格。在采用分区分离的方法改进后,不仅达到了中压电站锅炉蒸汽品质的要求,且使蒸汽容积和蒸发强度都超过了同参数锅炉的极限。     

水热煤技术在余热锅炉上的应用

我公司120万T/年重油催化裂化装置,配有一台燃烧式CO余热锅炉,该余热锅炉存在过热能力不足;炉膛压力偏高,再生烟气部分放空;受热面积灰严重,余热锅炉效率低;蒸汽品质不合格等问题,改造后CO余锅过热蒸汽产量由改造前40T/H左右提高到70T/H左右,蒸汽品质合格,装置能耗降低9个单位,经济效益显著。     

Ashland锅炉药剂在长庆石化公司的工业应用

长庆石化公司1.4Mt/a催化裂化装置中压汽包由于蒸汽夹带盐分现象严重,蒸汽品质难以有效控制,影响装置和气压机长周期运行。分析认为,过热蒸汽中的钠离子、二氧化硅含量超标,是导致气压机组汽轮机叶片结垢的直接原因。所以,抑制饱和蒸汽夹带盐分,进一步降低蒸汽中钠离子和二氧化硅含量,优化过热蒸汽品质,是保证汽轮机稳定运行的重点。该装置于2009年开始使用美国Ashland公司锅炉药剂,在催化裂化中压汽包系统投加AMERZINE15除氧剂和DREWPHOS2600缓蚀阻垢剂,经过连续2年的运行,饱和蒸汽钠离子、二氧化硅含量分别由6130.75μg/L、811.16μg/L降低至12.25μg/L、7.86μg/L,过热蒸汽钠离子、二氧化硅含量分别由107.74μg/L、88.43μg/L降低至27.94μg/L、9.92μg/L,汽轮机主气门开度由100%降低至70%,并在保护锅炉内壁、避免溶解氧腐蚀、提升锅炉水汽品质、优化气压机运行工况等方面取得了良好效果。     

50MW热电联供汽轮发电机组结垢原因分析及故障处理

介绍了自备发电站热电联供装置50MW汽轮发电机组汽轮机叶片结垢的原因和危害,采用低温低压饱和湿蒸汽清洗去除叶片结垢,在生产运行中加强蒸汽、凝结水品质监督,使热电联供发电机组汽轮机叶片结垢、积盐情况得到了明显改善,因蒸汽、凝结水品质原因引起的非计划停机、停炉、停电等设备事故没有发生,提高了热电联供汽轮发电机组的运行效率,保障了机组高效、安全、稳定、经济运行,满足大型石油化工装置安全稳定、长周期、连续运行的生产需要。     

蒸汽发生器堵管量对装置工作效率影响研究

核动力装置的立式自然循环蒸汽发生器工作中会由于U形管的腐蚀而需要堵管维修，其结果影响到蒸汽发生器和整个装置的工作效率。通过对一回路侧水阻力计算和二回路侧热工计算，对不同堵管量下蒸汽发生器的一回路冷却剂流量、二回路侧工作压强、蒸汽产量、蒸汽品质以及汽轮机有效功率的变化进行了详细的计算。根据计算结果对变化规律进行了分析，为蒸汽发生器的设计、维修技术的分析处理提供依据。     

浅析锅内装置对蒸汽湿度的影响

锅炉的锅筒内部汽水分离装置，由于安装时锅管内壁与扁钢没连续双面角焊缝形成间隙，造成蒸汽短路而影响蒸汽品质，本文作了计算。分析。     

工业锅炉饱和蒸汽湿度影响因素的实验研究

工业锅炉的蒸汽湿度是表征其蒸汽品质最重要的指标,影响其运行的经济性以及后续工艺和产品质量.目前对工业锅炉蒸汽湿度影响因素的定量分析研究较少.通过设计一台模拟工业锅炉实际运行的实验装置,消除测量误差,得出锅水含盐量、蒸汽压力和水位高度对蒸汽湿度影响规律,这对工业锅炉的设计和运行有现实意义.     

热泵式热能回收系统及其应用

蒸汽被广泛应用于工业与民用的供能系统中,蒸汽的减压、减温装置是其的关键设备。通过减压、减温后,蒸汽品质降低。为了有效利用低品质的热能,热泵式热能回收方法是有效的手段,本文提供了一个使用这一方法的有效例证。应用结果表明,该方法可以获得很大的经济和社会效益。     

推荐几组工业锅炉锅内装置方案

本文介绍了我国工业锅炉锅内装置的基本情况:指出了影响蒸汽品质的主要问题;并推出了国家“六五”重点攻关项目的成果,可适用于各型蒸汽锅炉的既简单、又有良好分离效果的几组锅内装置的组合方案。     

化工装置蒸汽冷凝液处理方法探讨

化工装置生产过程中 ,蒸汽作为反应原料、加热和动力介质 ,产生大量蒸汽冷凝液。其特点是分布面广 ,因设备、管道泄漏或腐蚀 ,难免含有各种杂质。本文介绍了三套不同类型化工装置在冷凝液回收利用方面的方法。1　某年产 30 0 kt天然气合成氨装置该装置根据冷凝液的不同品质 ,采用分散回收处理流程。回收冷凝液 87t/h。1 .1　工艺蒸汽冷凝液　工艺冷凝液来自加入工艺系统气体中进行化学反应的过剩蒸汽 ,经冷凝后从工艺气体中分离出来的 ,含有多种杂质的冷凝液 ,数量 31 t/h。要回收这部分冷凝液必须先进行预处理 ,以除去溶解在冷凝液中的杂质…     

Performance assessment of some ice TES systems

In this paper, a performance assessment of four main types of ice storage techniques for space cooling purposes, namely ice slurry systems, ice-on-coil systems (both internal and external melt), and encapsulated ice systems is conducted. A detailed analysis, coupled with a case study based on the literature data, follows. The ice making techniques are compared on the basis of energy and exergy performance criteria including charging, discharging and storage efficiencies, which make up the ice storage and retrieval process. Losses due to heat leakage and irreversibilities from entropy generation are included. A vapor-compression refrigeration cycle with R134a as the working fluid provides the cooling load, while the analysis is performed in both a full storage and partial storage process, with comparisons between these two. In the case of full storage, the energy efficiencies associated with the charging and discharging processes are well over 98% in all cases, while the exergy efficiencies ranged from 46% to 76% for the charging cycle and 18% to 24% for the discharging cycle. For the partial storage systems, all energy and exergy efficiencies were slightly less than that for full storage, due to the increasing effect wall heat leakage has on the decreased storage volume and load. The results show that energy analyses alone do not provide much useful insight into system behavior, since the vast majority of losses in all processes are a result of entropy generation which results from system irreversibilities.     

Aerodynamic performance effects of leading-edge geometry in gas-turbine blades

The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°,   −5°,   +5°,   +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods.     

Effect of co-cultivation of Chlamydomonas reinhardtii with Azotobacter chroococcum on hydrogen production

Chlamydomonas reinhardtii cc124 and Azotobacter chroococcum bacteria were co-cultured with a series of volume ratios and under a variety of light densities to determine the optimal culture conditions and to investigate the mechanism by which co-cultivation improves H₂ yield. The results demonstrated that the optimal culture conditions for the highest H₂ production of the combined system were a 1:40 vol ratio of bacterial cultures to algal cultures under 200 μE m^?2 s^?1. Under these conditions, the maximal H₂ yield was 255 μmol mg^?1 Chl, which was approximately 15.9-fold of the control. The reasons for the improvement in H₂ yield included decreased O₂ content, enhanced algal growth, and increased H₂ase activity and starch content of the combined system.     

Natural-gas fueled spark-ignition (SI) and compression-ignition (CI) engine performance and emissions

Natural gas is a fossil fuel that has been used and investigated extensively for use in spark-ignition (SI) and compression-ignition (CI) engines. Compared with conventional gasoline engines, SI engines using natural gas can run at higher compression ratios, thus producing higher thermal efficiencies but also increased nitrogen oxide (NO_x) emissions, while producing lower emissions of carbon dioxide (CO₂), unburned hydrocarbons (HC) and carbon monoxide (CO). These engines also produce relatively less power than gasoline-fueled engines because of the convergence of one or more of three factors: a reduction in volumetric efficiency due to natural-gas injection in the intake manifold; the lower stoichiometric fuel/air ratio of natural gas compared to gasoline; and the lower equivalence ratio at which these engines may be run in order to reduce NO_x emissions. High NO_x emissions, especially at high loads, reduce with exhaust gas recirculation (EGR). However, EGR rates above a maximum value result in misfire and erratic engine operation. Hydrogen gas addition increases this EGR threshold significantly. In addition, hydrogen increases the flame speed of the natural gas-hydrogen mixture. Power levels can be increased with supercharging or turbocharging and intercooling. Natural gas is used to power CI engines via the dual-fuel mode, where a high-cetane fuel is injected along with the natural gas in order to provide a source of ignition for the charge. Thermal efficiency levels compared with normal diesel-fueled CI-engine operation are generally maintained with dual-fuel operation, and smoke levels are reduced significantly. At the same time, lower NO_x and CO₂ emissions, as well as higher HC and CO emissions compared with normal CI-engine operation at low and intermediate loads are recorded. These trends are caused by the low charge temperature and increased ignition delay, resulting in low combustion temperatures. Another factor is insufficient penetration and distribution of the pilot fuel in the charge, resulting in a lack of ignition centers. EGR admission at low and intermediate loads increases combustion temperatures, lowering unburned HC and CO emissions. Larger pilot fuel quantities at these load levels and hydrogen gas addition can also help increase combustion efficiency. Power output is lower at certain conditions than diesel-fueled engines, for reasons similar to those affecting power output of SI engines. In both cases the power output can be maintained with direct injection. Overall, natural gas can be used in both engine types; however further refinement and optimization of engines and fuel-injection systems is needed.     

Hydrogen production by steam-gasification of carbonaceous materials using concentrated solar energy – V. Reactor modeling,optimization, and scale-up

A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified.     

汽轮机数字电液调节系统挂闸异常的技术完善

分析了200MW汽轮机数字电液调节系统在运行中存在的挂闸异常问题,采取了相应的技术处理措施,且运行实践效果良好。     

新型高压共轨ECU升压模块的数字化开发与优化

为了提高喷油器电磁阀的响应速率,提出了一种基于CPLD(复杂可编程逻辑器件)应用于高压共轨ECU的数字升压模块。鉴于该升压电路结构参数多,其升压电压的恢复响应要求高等特征,基于Pspice建立了升压电路的仿真模型,研究了不同电路参数下升压模块的输出特性,全面优化了该升压模块的性能。结果显示,该升压模块的最大转换效率可以达90%以上。在柴油发动机上对ECU的试验表明,升压电压最大波动不超过10%,其恢复时间仅为1.3ms,功率管最大温升仅为41℃,满足整机运行范围内ECU的需求。     

Trace metal chemistry and silicification of microorganisms in geothermal sinter, Taupo Volcanic Zone, New Zealand

As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied.     

Exergetic evaluation of 5 biowastes-to-biofuels routes via gasification

This paper presents the exergy analysis results for the production of several biofuels, i.e., SNG (synthetic natural gas), methanol, Fischer–Tropsch fuels, hydrogen, as well as heat and electricity, from several biowastes generated in the Dutch province of Friesland, selected as one of the typical European regions. Biowastes have been classified in 5 virtual streams according to their ultimate and proximate analysis. All production chains have been modeled in Aspen Plus in order to analyze their technical performance. The common steps for all the production chains are: pre-treatment, gasification, gas cleaning, water–gas-shift reactions, catalytic reactors, final gas separation and upgrading. Optionally a gas turbine and steam turbines are used to produce heat and electricity from unconverted gas and heat removal, respectively. The results show that, in terms of mass conversion, methanol production seems to be the most efficient process for all the biowastes. SNG synthesis is preferred when exergetic efficiency is the objective parameter, but hydrogen process is more efficient when the performance is analyzed by means of the 1st Law of Thermodynamics. The main exergy losses account for the gasification section, except in the electricity and heat production chain, where the combined cycle is less efficient.     

Decomposition of limestone in a solar reactor

The thermal decomposition of limestone has been selected as a model reaction for developing and testing an atmospheric open solar reactor. The reactor consists of a cyclone gas/particle separator which has been modified to let the concentrated solar energy enter through a windowless aperture. The reacting particles are directly exposed to the solar irradiation. Experimentation with a 60 kW reactor prototype was conducted at PSI's 90m² parabolic solar concentrator, in a continuous mode of operation. A counter-current flow heat exchanger was employed to preheat the reactants. Eighty five percent degree of calcination was obtained for cement raw material and 15% of the solar input was converted into chemical energy (enthalpy).The technical feasibility of the solar thermal decomposition of limestone was experimentally demonstrated. The use of solar energy as a source for high-temperature process heat offers the potential of reducing significantly the CO₂ emissions from lime producing plants. Such a solar thermochemical process can find application in sunny rural areas for avoiding deforestation.