锅炉省煤器超温爆管的原因分析与解决措施

针对省煤器布置方式及结构特点,就其磨损、腐蚀以及振动等因素引起省煤器超温爆管的内在原因进行分析。并且根据磨损、腐蚀、振动的机理提出了一些解决省煤器超温爆管的具有实用价值和借鉴意义的措施。     

不同温度条件下飞灰比电阻特性研究

比电阻是影响电除尘性能的关键因素,通过现场在线测定比电阻,采集飞灰样品测定试验室比电阻及数学模型计算相结合的研究方式,探讨了烟气温度对飞灰工况比电阻的影响,旨在为低低温工况下飞灰工况比电阻特性及除尘器性能研究等提供数据支持。     

燃气热水锅炉烟气低温腐蚀的预防及锅炉直供系统设计探讨

阐述了燃气锅炉烟气低温腐蚀机理,分析了影响腐蚀产生的因素及预防腐蚀发生的方法,提出了带炉前循环泵的锅炉直接供热系统改造方案。旨在优化锅炉房热力系统设计,避免因回水温度过低而引起的锅炉烟气低温腐蚀问题。     

高层建筑走廊排烟口与挡烟垂壁组合控制烟气的研究

高层建筑发生火灾时,走廊是烟气扩散的重要途径,同时也是人员逃生的必经之路.本文通过建立高层建筑内烟气流动的数学模型,采用k-ε两方程三维紊流模型,利用FLUENT软件对高层建筑火灾时不同排烟方式下的机械排烟进行了模拟,对比分析了高层建筑条形走廊内不同排烟口与挡烟垂壁之间的距离,以及不同挡烟垂壁高度情况下走廊内烟气的扩散状况.结果表明,在高层建筑条形走廊内设置挡烟垂壁能够较好地降低挡烟垂壁下游走廊内的危险性;挡烟垂壁与排烟口之间的距离对排烟的影响不大,挡烟垂壁的下垂高度是影响排烟效果的关键凼索;垂壁下垂高度每增加0.2 m,其下游平均温度将减小10℃左右.     

氯分种类对垃圾焚烧过程重金属迁移特性的影响

在管式反应炉上,通过加入有机氯(PVC)和无机氯(NaCl)研究了垃圾焚烧时氯对重金属迁移特性的影响。结果表明,氯分在低温下对重金属挥发几乎没有影响,只有在较高的焚烧温度下氯分才对重金属的挥发特性产生影响,且垃圾焚烧过程中氯分存在使重金属更易向飞灰或烟气中迁移,垃圾中有机氯对重金属迁移特性的影响要大于无机氯。氯的存在会显著改变分布在飞灰和烟气或底渣和飞灰间的重金属的分布特性     

燃煤电厂锅炉除尘用旋风分离器磨损因素的分析

对燃煤电厂锅炉除尘用旋风分离器磨损因素进行了分析，其中包括：旋风子内气固两相流动，飞灰性，烟气特性，旋风子结构、组合安装条件等。     

燃烧福建元烟煤的中温分离循环琉化床锅炉省煤貉磨损原因分析及其对策

某公司2台燃用福建无烟煤之75t／h循环流化床锅炉设计采用膜式省煤器,存在磨损、爆管等问题,分析其根源性原因主要是中温分离效率低、物料浓度高、粒径偏大、烟气流速高以及安装检修质量不佳等。为此,采取回料器放灰、控制炉膛漏风、提高安装检修质量、对省煤器管柬喷涂耐磨材料、加装防磨瓦等针对性措施,取得了较好的效果。     

人防工程内走廊坡度对烟气扩散的影响分析

为研究人防工程内走廊通道的坡度对烟气扩散的影响,运用火灾软件FDS建立一个长100m的走廊通道模型,对不同坡度的火灾工况进行模拟,分析对比不同工况下火灾上游区和下游区烟气的烟灰浓度、温度分布规律和扩散速率,从而得出走廊坡度对烟气扩散的影响.研究结果对于人防工程内部的设计及人员疏散提供参考.     

低温地板辐射采暖盘管泄漏数值模拟研究

由于受到腐蚀、磨损等自然或人为损坏,容易导致地板辐射盘管泄漏。文中通过分析低温地板辐射采暖盘管传热特点,建立低温地板辐射盘管泄漏的二维数学模型,利用CFD软件模拟盘管泄漏前后地板和地板表面温度变化规律。研究结果表明:泄漏后,盘管泄漏口附近温度迅速升高,随着时间推移,高温区域向周围扩大;地板表面温度分布曲线呈抛物线形状,且其温度高于泄漏前约1.3℃,此温差可以为红外成像仪判断出泄漏位置提供有利条件。     

外界风下竖井—走廊空间烟气蔓延特征研究

本文采用FDS火灾模拟软件针对外界风作用下竖井走廊空间的火灾烟气蔓延扩散特征进行研究,发现外界风、火源位置以及竖井窗口开启高度等对走廊内烟气能否进入竖井形成烟囱效应具有重要影响.外界风对走廊烟气进入竖井形成烟囱效应具有抑制作用,火源位于走廊中间时,利于积聚更多烟气,流入竖井形成烟囱效应.随着竖井窗口开启高度升高,烟囱效...     

关于自激式水浴脱硫除尘器的新应用技术

根据自激式水浴脱硫除尘器的结构及工作原理,分析了影响除尘效率、脱硫效率、烟气带水控制、液位控制、防腐耐磨等因素,对自激式水浴脱硫除尘器进行改造,同时增加省煤器换热面积,降低进入引风机尾部的烟气温度,杜绝了引风机振动。     

Experimental Study of the Interaction Between Water Sprays and Smoke Layer

This paper concerns the interaction between water sprays and a smoke layer in a corridor, without any interaction with fire activity. Three water sprays are tested, a high-pressure water mist system and two sprinkler systems under different operating pressures. Our study aims to compare the impact of these three sprays on the smoke layer, based on the analysis of temperature and transmittance profiles. Characterization of the smoke layer before spray activation, based on either temperature or transmittance was found to be similar, providing a smoke free layer at around middle height in the corridor. During spray operation, discrepancies were observed in some cases depending on whether the smoke layer was studied based on the temperature or the transmittance profiles. Spray operation may provide gas cooling, resulting in homogeneous temperature profiles, while vertical variations of droplet size and soot or droplet concentration can still induce a variation in transmittance. The impact of water spray on the smoke layer varies with the spray system. For the water mist system and the highest-pressure sprinkler system, the spray operation induces a complete de-stratification with well-mixed steady-state conditions along the corridor as well as strong smoke cooling and visibility alteration. With the lowest-pressure sprinkler system, only a localized alteration of this stratification is observed under the spray, while the environment remains thermally and optically stratified downstream in the corridor despite spray operation. Relationships described in the literature were used to confirm and explain these observations. Ratios were evaluated to compare the drag effect due to the spray and the buoyancy effect related to the fire. All tests provided ratios of drag number over buoyancy number much greater than one. This confirms the ability of these relationships to predict the occurrence of de-stratification. Qualitatively, the highest ratios were found for the high pressure system and for the water mist system, which actually led to the most important de-stratification effects. In contrast, the weaker ratio found for the lower pressure system was still above one, i.e., coherent with a de-stratification which did not affect the whole corridor however.     

论循环流化床锅炉常见问题和缺陷的原因及防止

论述了循环流化床锅炉的主要特点及运行原理,对该锅炉在运行过程中常见的水冷壁爆管、省煤器泄露及爆管、尾部烟道灰分再燃等现象进行了描述,并进行了原因分析,研究了各问题的防治措施,对循环流化床锅炉的推广应用具有重要意义。     

大庆市某锅炉房46m高砖烟囱裂缝剖析

介绍了某 46m高烟囱 ,由于锅炉设备安装时没有安装省煤器装置 ,至使进入砖烟囱之烟气温度升高 ,造成烟囱筒壁内抗温度应力钢筋不足 ,出现竖向裂缝。并验算了 2个截面。     

Smoke concentrations inside and outside of a corridor-like enclosure

This work presents smoke measurements and correlations inside and outside of a corridor-like enclosure fires in order to determine the effects of burning on smoke concentrations inside and outside the enclosure. Thirty eight experiments were performed in a three metre long corridor-like enclosure having a cross section 0.5 m×0.5 m, door like openings in the front panel and a gaseous burner located near the closed end. Smoke concentrations were measured at two locations inside the enclosure and also in the exhaust duct of a hood collecting the fire gases from the enclosure. It was found that smoke concentration in the exhaust duct decreased whereas smoke concentration inside the enclosure increased after the flames started moving towards the opening and external burning occurred. This increased smoke concentration inside the enclosure was caused by reversion of the flow pattern inside the enclosure after the flames moved past a point towards the opening. Namely, the flow pattern changed direction behind the flame front in the sense that hot gases in the upper layer were travelling backwards towards the closed end of the corridor thus contributing to smoke increase inside the enclosure. This change of flow pattern was confirmed in all experiments by bidirectional probe velocity measurements in the upper and lower layer as well as by oxygen concentrations and temperature measurements inside the enclosure. These results are useful for CFD validation and specifically applicable for assessing smoke hazards in corridor fires in buildings where smoke concentrations can be much larger than anticipated owing to leakage to adjacent rooms behind a moving flame front.     

影响内燃机气缸窜气的相关因素分析及对策

气缸窜气量的大小是衡量内燃机技术性能的重要指标。气密性差是导致气缸，活塞（环）等机件异常磨损，机油过量消耗以及过早氧化变质的重要因素。同时，也会造成内燃机过热，活塞（环）卡缸，熔着磨损以及活塞环断裂等事故。本文对影响内燃机窜气的相关因素进行了分析，论述了降低和预防气缸窜气的措施和方法。     

通风对竖井型隧道火灾烟气特性影响试验研究

通过隧道火灾模型试验,研究纵向通风对竖井排烟效果及隧道内纵向烟气温度分布的影响。试验考虑不同火源热释放速率和纵向风速。结果表明：纵向风速对正庚烷池火热释放速率存在影响,对于较小正庚烷池火（≤11 cm）,火源热释放速率基本不随纵向风速而改变;对于较大正庚烷池火（≥14 cm）,火源热释放率随风速的增加先降低后基本保持恒定。此外,当隧道内风速较小时,竖井内烟气附壁排出,竖井后方烟气温度较低,控烟效果较好;当隧道内风速较大时,竖井内烟气出现边界分离,竖井后方温度升高,烟气蔓延距离增加,竖井排烟效果较差。因此,建议当竖井型隧道内发生火灾时,应尽量采用自然通风或较低的内部通风,避免较高风速。     

Experimental Validation of Smoke Detector Spacing Requirements and the Impact of these Requirements on Detector Performance

Changes were made to the smoke detector siting requirements for beamed ceilings in the 2007 edition of NFPA 72, the National Fire Alarm Code. These changes were based on a modeling studying. A series of full-scale fire tests were conducted to validate the findings of the modeling study for level corridor ceilings with and without beams. This paper provides an overview of the experimental testing conducted, presents a brief summary of the findings of the experimental validation, and addresses the impact of deep-beam profiles on level ceilings with respect to smoke detector response. Furthermore, the impact of deep-beamed ceilings on detector response is evaluated with respect to the citing requirements of the 2002 and 2007 editions of NFPA 72.     

室外风对走廊温度分层和房间自然排烟的影响

为研究室外风对走廊中火灾烟气分层特性和自然排烟的影响,在相似原理的基础上开展了1/3 缩尺寸实验。通过改变火源功率、室外风速和外窗尺寸,结合对走廊火灾烟气分层特性和自然排烟效果的判断,找出使分层失效的临界室外风速以及使自然排烟失效的临界室外风速,运用量纲分析和数据拟合的方法分析无量纲火源功率和无量纲临界失效风速之间的关系。研究发现,温度分层无量纲临界失效风速与无量纲火源功率呈现良好的线性关系,温度分层临界失效风速随窗口尺寸减小而增大;自然排烟无量纲临界失效风速与无量纲火源功率呈现显著的对数函数关系,窗口尺寸相同时,火源功率越大,自然排烟临界失效风速越大。     

基于一种结构钢质防火门的防烟性能研究

开发了一种全尺寸防火门防烟性能测试装置,并建立了一套测试程序,来研究不同压力差和温度下防火门的烟气泄漏速率。选取目前市面上典型结构的单扇与双扇钢质防火门,测试其防烟性能,发现典型钢质防火门在不同温度及压差下均有较大泄漏率,其防烟性能较差,无法有效阻挡火灾烟气。选取同尺寸防火门,对其加装三角形空心防烟密封条并进行防烟性能测试,结果表明,防烟密封条能有效减小门扇与门框间隙,从而减小防火门烟气泄漏率,提升其防烟性能;门扇数量对不同试验温度下防烟密封条的密封效果有一定影响,单扇门在加装三角形空心防烟密封条后防烟性能提升更多,且单扇防火门加装密封条后中等温度下的防烟性能提升幅度更大,而双扇防火门加装密封条后环境温度下的防烟性能提升幅度更大。