浅谈煤场喷淋系统的改造

自从珠海电厂进行掺烧以来,煤场煤种较杂发生煤场自燃现象增多,因灭火需用大量的水且用水频繁,造成频繁起动消防增压泵,针对这些问题,我们从节能角度考滤,对原煤场水喷淋系统进行了改造,很好地解决了煤场灭火用水问题。     

燃煤发电厂储煤场自燃热损失的评估

煤炭周转不合理导致了自燃在燃煤发电厂露天储煤场频频发生,降低了入炉煤的发热量,增加了灰分,直接影响锅炉机组运行的安全性和经济性.为了掌握不同存煤阶段煤堆热损失的变化规律,本文以煤场某典型煤种为研究对象,开展了煤场温度监测试验,并在试验的基础上建立自燃热损失评估的数学模型.研究结果表明,存煤初期煤堆热损失以线性函数规律增加,入场存放30d后煤堆热损失以幂指数函数增长的趋势急剧增加,因此应在30～40d内完成入场煤的周转,实现合理存煤、用煤,减少入炉前发热量的损失,为开发燃煤发电厂储煤场自燃热损失评估系统、降低发电成本提供奠定了基础.     

煤场监控自动聚焦系统研究

为了对煤场进行集中监测与管理,本文对煤场监控系统进行了研究,重点研究了监控系统中自动聚焦功能．良好的自动聚焦功能对后续监控处理奠定良好的基础。经实验验证,本系统运行可靠、实时性好,用于煤场的管理与操作,具有明显的经济效益和社会效益。     

火电厂输煤系统煤场自燃防止措施初探

火力发电厂需要大量贮煤,以确保正常生产的需要。但煤在火电厂经过长时间的堆积和磨合,在条件适可情况下会产生缓慢的氧化反应从而发热,这将导致煤的温度逐渐升高,进而发展成为煤自燃起火。这将给发电企业造成相应的经济损失,同时也容易引起电厂火灾。如何有效地防止火电厂煤场的自燃,对电力企业安全生产和经济运营至关重要。     

利用低温热管技术防止圆形封闭煤场煤堆自燃

提出了一种圆形封闭煤场防止煤堆自燃的方法,通过在挡煤墙地带设置重力式低温热管来释放煤的氧化热,运行过程稳定,无能耗。该方法人工维护量小,初投资低,易于实施,因此,具有很好的应用前景。     

封闭式圆形煤场储量研究

对于圆形煤场的储煤量,目前较多采用估算的方式,与实际的误差很大,其对圆形煤场尺寸的确定有很大的影响。通过对圆形煤场的堆煤方式、原理进行分析,合理确定圆形煤场煤堆的边界条件。本次利用计算机CAD、三维建模,对各尺寸系列的圆形煤场进行了储量计算,为工程设计提供参考数据,以进一步推进圆形煤场的广泛应用。     

行业/企业动态

韶钢 完成60kN杠杆式二等标准测力机改造；新钢钒 格里坪煤场汽车衡启用；中铝河南分公司 成功承办计量专业技能竞赛；沱牌曲酒股份有限公司顺利通过“C”标志复查审核     

测温光纤系统在自燃发火煤层中的应用

煤层自燃发火是煤矿生产的主要灾害之一,严重威胁着煤矿安全生产,为了控制这类灾害的发生,煤层自燃发火的预测预报技术备受关注。在煤层氧化时,首先要放出热量使煤体温度升高,这是煤层发火征兆必备条件之一。根据龙煤集团鹤岗分公司兴安煤矿实际情况,引进测温光纤技术,通过对自燃发火煤层温度变化的监测监控,及时、准确地预测预报煤炭自燃发火征兆,判断自燃发火发展的趋势,及时采取措施降低温度,达到防止火灾发生的目的。     

凝胶自燃法制备低温烧结Z型铁氧体材料

采用干凝胶自燃工艺制得铁氧体纳米粉，研究了干凝胶的自燃烧过程，利用xRD分析了纳米粉的晶体结构与晶粒尺寸，结合TG-DTA数据，设计了粉体处理与陶瓷样品的烧结工艺。选用自燃粉制得的低温烧结Z型铁氧体材料性能为μi≈4(300MHz)；Q≥150；fr≥1.5GHz。     

火电厂煤场钢结构有限元设计输出图的规范化研究

为了消除火电厂露天煤场对环境的影响,要求对火电厂煤场进行封闭改造。火电厂煤场的封闭改造采用大型钢结构。通过有限元分析软件对大型钢结构进行结构优化设计后输出的图形不能满足施工图要求。应用AutoLISP编程实现对有限元软件输出的AutoCAD图形自动规范化处理,免除了繁重的手工修改工作,缩短了MIDAS输出图形的后期处理时间,提高了大型钢结构设计的工作效率。     

燃煤电厂储煤场煤堆自燃及防治措施的试验研究

燃煤电厂储煤场煤堆氧化、自燃会导致存煤灰分升高,热值降低,影响电厂运行经济性和安全性.本文选取了南方某电厂堆放的两种典型烟煤为研究对象,考察了煤质特性、外部环境、堆放时间和温度空间分布等因素对煤堆自燃发火性的影响.结果表明,垂直于煤堆表面1m深度内,易出现煤堆自燃敏感温度70-90℃;煤堆温度随高度增加呈现逐渐降低的趋势,煤堆迎风面内部温度低于背风面内部温度.针对煤堆深层注水法及喷洒粉煤灰浆法两种自燃防治措施,评价了其自燃抑止的有效性.     

Effects of intrinsic properties,particle size and specific surface area on WOP and spontaneous combustion susceptibility of coal

This study examines the effects of intrinsic properties, particle size, and specific surface area (SSA) of coal on spontaneous combustion. Moreover, it analyzes the underlying mechanism of spontaneous combustion from particle size, SSA and gas adsorption perspectives. The susceptibility of coal to spontaneous combustion is studied by wet-oxidation potential (WOP) method. Coal residues left after the WOP experiment are analyzed for change in structural and compositional behaviour. The study revealed an inverse relationship between the particle size and SSA of coal. Spontaneous combustion susceptibility increased with increase in volatile matter and decreased with increase in fixed carbon content of coal. The optimum moisture content of coal resulting maximum spontaneous combustion tendency is determined 6%. Decrease in particle size and increase in SSA augmented the spontaneous combustion propensity of coal. With decrease in coal particle size from 425 to 850 to < 38 µm, the mean D₅₀ value decreased by 27 times, the mean SSA increased by 42 times and coal spontaneous combustion susceptibility increased almost by 2 times. Critical coal particle size is determined 38–74 µm (D₅₀ = 50.56 µm), below which no appreciable change in oxidation rate is observed. Moreover, two models are developed to predict the spontaneous combustion susceptibility of coal based on particle size (D₅₀) and SSA.     

煤岩体水力致裂弱化技术及其进展

针对煤矿开采中坚硬顶煤（板）冒落性差的问题,讨论了煤矿生产中由此产生的顶煤放出率、冲击 矿压、自燃发火和瓦斯积聚等技术难题;分析了坚硬顶煤（板）水力致裂弱化技术的岩体水力致裂裂缝扩展行 为规律、渗透压力对裂隙岩体宏细观结构的改造作用及其宏观力学响应,水压裂缝扩展形态控制技术,钻孔封 孔技术和岩体水力致裂弱化的监测监控的研究现状和技术发展趋势。     

Heat effect of the oxygen-containing functional groups in coal during spontaneous combustion processes

The heat generated from the reactions of oxygen-containing functional groups in coal has been studied using organic chemistry and quantum chemistry analysis methods. Structural models of the oxygen-containing functional groups in coal were established and used to analyze the reactions of these groups during spontaneous combustion. The Gibbs free energy and enthalpy changes associated with these reactions were determined using quantum mechanical analysis, and the results indicated that the dehydration and dehydrogenation reactions of the hydroxyl groups in coal were only mildly exothermic, whereas reactions involving the oxidation of the carbonyl groups were much more exothermic. In contrast, reactions resulting in the generation of carbon monoxide were endothermic. By comparing the heat release characteristics of the reactions of the oxygen-containing functional groups with the levels of oxygen consumption and gas production, as well as temperature profiles of the reactions, it was concluded that the decomposition of oxygen-containing functional groups is critical to the production of heat during the initial stages of the spontaneous combustion of coal and that oxidation does not occur during this period. These results also explain why the temperature of coal rises slowly during the initial stages of its spontaneous combustion.     

Polycyclic aromatic hydrocarbon (PAH) emissions from a coal-fired pilot FBC system

Due to the extensive amount of data suggesting the hazards of these compounds, 16 polycyclic aromatic hydrocarbons (PAHs) are on the Environmental Protection Agency (EPA) Priority Pollutant List. Emissions of these PAHs in the flue gas from the combustion of four coals were measured during four 1000h combustion runs using the 0.1MW heat-input (MWth) bench-scale fluidized bed combustor (FBC). An on-line sampling system was designed for the 16 PAHs, which consisted of a glass wool filter, condenser, glass fiber filter, Teflon filter, and a Tenax trap. The filters and Tenax were extracted by methylene chloride and hexane, respectively, followed by GC/MS analysis using the selective ion monitoring (SIM) mode. In this project, the effects of operating parameters, limestone addition, chlorine content in the coal, and Ca/S molar ratio on the emissions of PAHs were studied. The results indicated that the emissions of PAHs in an FBC system are primarily dependent on the combustion temperature and excess air ratio. The injection of secondary air with high velocity in the freeboard effectively reduces PAH emissions. The addition of extra limestone can promote the formation of PAHs in the FBC system. Chlorine in the coal can possibly lead to large benzene ring PAH formation during combustion. The total PAH emission increases with an increase in the sulfur content of coal. Incomplete combustion results in PAHs with four or more benzene rings. High efficiency combustion results in PAHs with two or three benzene rings.     

我国煤矿矿井防灭火技术研究综述

总结了近年来我国在煤矿矿井火灾预测预报理论及方法、矿井煤炭自燃火源区域探测方法、矿井防灭火技术、外源火灾检测及防治和矿井防灭火决策系统等方面的研究和应用进展,分析了我国在煤矿矿井防灭火技术研究和应用中存在的问题。     

煤矿综采面安全生产评价研究

[摘要]矿井事故高发区域是煤矿综采工作面,煤矿环境的特殊在很大程度上增加了确保安全生产的难度系数,矿井生产具有其他行业所不具有的特殊性、复杂性以及多变性,其中发生率较高的矿井事故类型有透水、煤炭自燃、瓦斯或煤尘爆炸以及职业病等。本文首先介绍了综采工作面常见事故类型,其次阐述了构建煤矿综采面安全生产评价指标体系应遵循的原则,最后对确定综采工作面安全生产评价指标权值加以探讨。     

自燃煤矸石胶凝材料中钙矾石形成研究

采用XRD分析了自燃煤矸石胶凝材料中活性Al2O3在不同因素影响下水化形成钙矾石的情况.研究结果表明,在相同条件下芒硝存在,时自燃煤矸石中活性Al2O3水化生成钙矾石,而含等量硫的石膏存在时水化浆体中不但有水化产物钙矾石还有未反应的石膏;胶凝体系中不含熟石灰时,活性Al2O3水化首先生成石膏,随着水化的进行再转化成钙矾石,而在有熟石灰时水化则直接生成钙矾石;矿渣促进了自燃煤矸石中Al2O3水化形成钙矾石.     

风包粉系列浓淡煤粉燃烧技术的研究

总结了哈尔滨工业大学15年来对浓淡煤粉燃烧技术的研究成果，阐述了浓淡煤粉燃烧技术的原理及所具有的风包粉流动特点，并通过工业试验验证了风包粉原理。针对我国电站锅炉燃煤的特点，提出了需要解决的5个问题，指出了浓淡燃烧技术的发展方向。     

Aqueous three-phase foam supported by fly ash for coal spontaneous combustion prevention and control

This work deals with the preparation and characterization of fly ash (FA) supported aqueous three-phase foams containing N₂ for coal spontaneous combustion prevention and control. Uniform and dense three-phase foams featuring FA contents between 20 wt.% and 33 wt.% are prepared in batch mode using a home-made foam generating column with an internal Venturi tube. The effect of FA on the foamability, static and dynamic stability of the three-phase foams is discussed. Compared with two phase foams, the FA supported three-phase foams manifest higher static and dynamic stability, which increases with the FA content. Base on the excellent static and dynamic stability, a structure model to attach FA particles at the N₂–water interfaces of the three-phase foams was proposed to elucidate the observed behaviors. The as prepared FA supported three-phase foams, exhibiting excellent coal fire extinguishing characteristic, can be used as a promising fire extinguishing material, especially for preventing the large coal area spontaneous combustion or extinguishing fire in high and unknown locations in goaf.