CFB锅炉结焦分析及解决方案

介绍了CFB锅炉结焦的分类及结焦机理,分析了影响结焦事件发生的几类因素,对预防结焦事故提出了控制措施。     

关于CFB锅炉布风板结焦的研究

本文围绕布风板结焦事故工况,介绍如何辨别结焦是否发生,布风板发生结焦后如何处理,分析结焦原因并提出预防措施.     

1025T/H直流锅炉送风机故障检修导致炉膛结焦的分析与处理

对配置切向燃烧一次风反切系统的煤粉炉水冷壁结焦事故的分析，指出防止炉膛结焦的重要措施是防止炉内气流发生旋转方向的改变。     

“W”型火焰锅炉掺烧烟煤结焦原因分析及对策

简要分析了某电厂"W"型火焰锅炉在掺烧烟煤后,炉膛结焦加剧,频繁发生垮焦,砸伤甚至砸爆水冷壁管事故的原因。着重介绍了该电厂通过对容易结焦区域的一系列改造,成功避免了"W"型火焰锅炉掺烧烟煤后的结焦问题,对同类型电厂具有一定的借鉴作用。     

基于结焦机理的有机热载体炉炉管在线寿命评估系统研究

总结了近年来国内有机热载体炉事故案例,得出结焦是造成爆管的最直接原因。并分析了导热油劣化的原因,找出了现有结焦检测方法和寿命评估方法的不足,由此提出了基于管壁结焦机理的有机热载体炉炉管在线寿命评估系统的研究和开发,并详细阐述了导热油热稳定性热重差热分析评定、炉管壁温红外成像测量技术和管壁结焦流动传热数学模型构建等在线寿命评估系统的关键技术。     

1000MW燃煤机组锅炉冷灰斗浇注料结焦全过程应对及分析

锅炉结焦是燃煤工业锅炉运行中比较普遍的现象。它会破坏正常燃烧工况,减少锅炉出力,破坏正常水循环,造成爆管事故,严重时还会使炉膛出口堵塞而被迫停炉。为此文中对某电厂1 000 MW燃煤机组锅炉冷灰斗结焦问题进行了全过程应对及分析,提出了热态下炉内结焦区域诊断和炉膛深度洁净长期控焦方法,彻底解决了历时长达3个月的锅炉多区域严重结焦问题,对今后同类问题的解决具有较强的参考价值。     

大唐黄岛发电有限责任公司5、6号锅炉结焦分析与防范措施

大唐黄岛发电有限责任公司(以下简称黄岛公司)5、6号机组2017年12月份以来锅炉严重结焦影响了机组的安全、经济运行。经过对锅炉结焦的分析,黄岛公司制定并采取了一系列措施,使锅炉结焦得到缓解,从而保证了机组安全稳定运行。     

吹灰导致锅炉MFT事故分析

对于燃煤锅炉结焦积灰的问题,已经严重威胁到锅炉的安全性和经济性,轻则造成换热面泄漏,影响锅炉效率;重则引发"非停"事故,甚至带来人生安全事故隐患。文章用某燃煤电厂由于结焦积灰严重,吹灰时造成大量跨灰现象,导致锅炉MFT保护动作案例为切入点,分析了事故原因,提出了一系列防范措施,为今后的生产工作指明了方向。     

甘蔗渣锅炉燃烧装置的节能改造

我国很多地区都采用固定炉排烧生物质燃料的锅炉,这些锅炉大都存在炉排易结渣、燃烧效率低、因燃烧故障事故停炉多等问题。通过对某糖厂85 t/h甘蔗渣锅炉燃烧装置进行改造,彻底解决了该甘蔗渣锅炉炉排堆渣结焦现象,提高了锅炉燃烧效率,解决了因炉排结焦停炉事故的发生,达到了较好的节能效果。     

煤粉锅炉炉膛出口受热面结焦问题研究

燃用神华类易结焦煤种的电厂在持续高负荷运行时,其炉膛出口受热面易发生结焦问题,以往以控制炉膛出口烟温作为防止结焦的措施。根据工程实践情况并从煤灰颗粒与烟气的辐射传热特性不同出发,提出了烟温与煤灰颗粒温度的区别,并指出实际运行中炉膛出口受热面发生结焦问题的主要原因在于煤灰颗粒在到达炉膛出口处时其温度仍高于软化温度(ST)。基于此,以单个煤粉颗粒为研究对象,重点计算分析了燃烧速率对炉膛出口处煤灰颗粒温度的影响。结果表明,提高煤粉燃烧速率可以有效地降低炉膛出口处的煤灰颗粒温度,从而极大地改善结焦问题。介绍了上海外高桥第三发电厂首创的广义回热技术,对比分析可知,此技术对防治锅炉结焦更为经济、有效。     

Economie d'énergie en trigénération

Trigeneration is defined as the production of three useful forms of energy—heat, cold and power—from a primary source of energy such as natural gas or oil. For instance, trigeneration systems typically produce electrical power via a reciprocating engine or gas turbine and recover a large percentage of the heat energy retained in the lubricating oil, exhaust gas and coolant water systems to maximize the utilization of the primary fuel. The heat produced can be totally or partially used to fuel absorption refrigerators. Therefore, trigeneration systems enjoy an inherently high efficiency and have the potential to significantly reduce the energy-related operation costs of facilities. In this paper, we describe a model of characterization of trigeneration systems trough the condition of primary energy saving and the quality index, compared to the separate production of heat, cold and power. The study highlights the importance of the choice of the separate production reference system on the level of primary energy saving and emissions reduction.     

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.     

我国车用柴油机的技术现状及发展趋势

本文根据国内外信息和资料，分析了我国目前车用柴油机制造技术方面与国际水平所存在的差距，预测今后若千年内车用柴油机要向节能降耗、应用增压技术、提高可靠性、降低排放、采用电控技术方面发展，以尽快接近和赶上国际先进水平．     

Wood feedstock qualities for energy conversion and the potential for their biological improvement

The accomplishments of the Wood Feedstock Quality activity of Task V of the International Energy Agency's Bioenergy Agreement are described. Areas investigated included energy products and co-products from woody biomass; effects of harvesting, processing and storage on feedstock quality; the effect of feedstock quality on the efficiency of biomass conversion; the potential for biological improvement; the need for standardization of feedstock qualities; and the need for clonal characterization.     

静电除尘器和湿法烟气脱硫装置对烟气汞形态的影响与控制

利用安大略标准方法和在线汞监测技术对6套典型燃煤电站锅炉静电除尘器(ESP)和湿法烟气脱硫(WFGD)装置前后烟气汞的浓度及形态进行了测试,并研究了2种装置对烟气汞形态转化的影响及其汞控制能力.结果表明:ESP对飞灰的捕获直接降低了烟气中颗粒汞的比例,从已测试的典型燃煤锅炉来看,ESP前的燃煤烟气中颗粒汞的平均比例在30%左右,经ESP后颗粒汞所占比例降至5%左右;经WFGD装置洗涤后,烟气中汞的形态发生了较大的改变,二价汞基本被捕获,进入WFGD装置的烟气中二价汞的比例越高,WFGD装置对烟气汞的脱除效率也越高.配置有选择性催化还原(SCR)脱硝装置+ESP+WFGD尾部烟气处理装置的燃煤电厂,能够很好地控制燃煤烟气汞的排放.     

车用汽油机HC排放分布规律研究

根据大量ＨＣ排放实测数据，运用数理统计手段，研究确定国产主要车型货车和轿车汽油机ＨＣ排放分布规律及分布参数，进而建立了相应国车用汽油机的ＨＣ排放分布计算模型。它对准确对计算车用汽油机ＨＣ排放分布数值和评价车用汽油机ＨＣ排放对大气环境的影响等，具有十分重要的作用。     

尿素喷射计量试验控制系统的硬件开发与测试

尿素喷射计量试验是完成车载尿素喷射计量装置的功能开发和性能考核的重要环节,而该试验内容离不开尿素喷射计量试验控制系统(UCDS)的开发,本文基于尿素喷射计量系统(UDS)的组成,开发出了试验所需的控制系统的硬件平台,用模块化的设计思想对UDCS控制器进行了方案设计,测试结果与设计目标一致,达到了尿素喷射计量试验的要求.     

Characterization and prediction of biomass pyrolysis products

In this study some literature data on the pyrolysis characteristics of biomass under inert atmosphere were structured and analyzed, constituting a guide to the conversion behavior of a fuel particle within the temperature range of 200-1000 °C. Data is presented for both pyrolytic product distribution (yields of char, total liquids, water, total gas and individual gas species) and properties (elemental composition and heating value) showing clear dependencies on peak temperature. Empirical relationships are derived from the collected data, over a wide range of pyrolysis conditions and considering a variety of fuels, including relations between the yields of gas-phase volatiles and thermochemical properties of char, tar and gas. An empirical model for the stoichiometry of biomass pyrolysis is presented, where empirical parameters are introduced to close the conservation equations describing the process. The composition of pyrolytic volatiles is described by means of a relevant number of species: H₂O, tar, CO₂, CO, H₂, CH₄ and other light hydrocarbons. The model is here primarily used as a tool in the analysis of the general trends of biomass pyrolysis, enabling also to verify the consistency of the collected data. Comparison of model results with the literature data shows that the information on product properties is well correlated with the one on product distribution. The prediction capability of the model is briefly addressed, with the results showing that the yields of volatiles released from a specific biomass are predicted with a reasonable accuracy. Particle models of the type presented in this study can be useful as a submodel in comprehensive reactor models simulating pyrolysis, gasification or combustion processes.     

Economic viability assessment of sustainable hydrogen production,storage, and utilisation technologies integrated into on- and off-grid micro-grids: A performance comparison of different meta-heuristics

In recent years, there has been considerable interest in the development of zero-emissions, sustainable energy systems utilising the potential of hydrogen energy technologies. However, the improper long-term economic assessment of costs and consequences of such hydrogen-based renewable energy systems has hindered the transition to the so-called hydrogen economy in many cases. One of the main reasons for this is the inefficiency of the optimization techniques employed to estimate the whole-life costs of such systems. Owing to the highly nonlinear and non-convex nature of the life-cycle cost optimization problems of sustainable energy systems using hydrogen as an energy carrier, meta-heuristic optimization techniques must be utilised to solve them. To this end, using a specifically developed artificial intelligence-based micro-grid capacity planning method, this paper examines the performances of twenty meta-heuristics in solving the optimal design problems of three conceptualised hydrogen-based micro-grids, as test-case systems. Accordingly, the obtained numeric simulation results using MATLAB indicate that some of the newly introduced meta-heuristics can play a key role in facilitating the successful, cost-effective development and implementation of hydrogen supply chain models. Notably, the moth-flame optimization algorithm is found capable of reducing the life-cycle costs of micro-grids by up to 6.5% as compared to the dragonfly algorithm.     

Permeability and alteration within the Soultz granite inferred from geophysical and flow log analysis

The 1993 stimulation tests carried out in well GPK1 at Soultz, Alsace, France, showed that out of the thousands of fractures cross-cutting the granite, only a limited number of natural fractures contributed to fluid flow. A comparison between the petrophysical properties of the rock and the interpretation of the hydraulic test results is proposed as a means of determining the distribution of the natural permeable fractures. Gamma-ray spectral logs and other geophysical logs (caliper, bulk density, P-wave slowness, and photoelectric factor) revealed some petrographical variations within the Soultz massive granite, as well as altered/fractured zones that act as preferential pathways for fluid flow as indicated by flow logs. Fluid losses during circulation tests have been estimated on the basis of statistical analysis of gamma-ray readings, and of potassium and thorium contents.