循环流化床锅炉点火实践

随着节能与环保要求的日益提高,更多的城市在致力于采用集中供热来适应节能与环保的要求。我厂应市场要求,同中科院工程热物理所联合开发,由我厂设计、制造的DHF29—1.6/150/90—P型循环流化床热水锅炉(简称29MW锅炉)已于1993年12月2日在河南濮阳中原油田供热厂点火成功,投入运行。该炉型是我国目前最大容量的循环流化床热水锅炉,它的投运标志着我国工业热水锅炉上了一个新台阶。     

循环流化床锅炉点火的一些体会

针对循环流化床锅炉燃烧方式的独特性，简要总结了循环流化床锅炉的点火经验，对解决点火过程中存在的问题提出了建议。     

高炉煤气在循环流化床锅炉中的应用探讨

循环流化床锅炉在掺烧高炉煤气的过程中会产生一些不良的后果，文章分析了这些后果产生的原因，并提出了相应的改进措施。     

循环流化床锅炉的点火启动与燃烧调整探析

220t/h循环流化床锅炉在韶钢热电厂是首次应用,对锅炉运行人员来说,正确、快速掌握点火启动与燃烧调整技术,有着十分重要的意义.文章着重对220t/h循环流化床锅炉的点火启动与燃烧调整进行探讨和分析.     

循环流化床煤泥锅炉木炭点火新工艺

兖州矿业（集团）公司鲍店煤矿煤泥热电厂在循环流化床煤泥锅炉运行初期使用原先设计的由点火系统点火，点火时间为90～100min，点火时间长、耗资大、易结焦。改用木炭点火以后，点火时间缩短为30～50min，耗资仅为原来的1／3，极有推广应用的价值。     

循环流化床锅炉的床下动态点火

1　床下动态点火1.1　具有较高挥发份燃料 (Vr>10 )的点火启动这类煤的燃点一般较低 (4 5 0～ 5 0 0℃ ) ,点火相对简单 ,其操作步骤如下 :首先应检查并做好锅炉点火前的各项准备工作。向炉内铺设约 4 5 0mm厚的底料 ,作冷态试验 ,检查布风板布风均匀性及确定最低流化风量。冷态试验合格后 ,启动引风机 ,3～ 4min后则可启动一次风机 (可先关闭一次风道风门 ,只以点火风作为流化风 )增大送风量 ,使料层达到最低流化状态 ,启动点火油泵 ,调整油压后点火 ,并调整火焰中心 ,调整风室温度大约 70 0℃ (可适度开启一次风门 )。待底料加热至 4 5 0…     

一种新型点火技术在循环流化床锅炉上的应用

介绍了一种新的分层流态化点火方法和防止结焦新措施,点火成功率可以达到１００％。     

循环流化床锅炉两种点火方式的介绍与分析

对循环流化床锅炉两种点火方式进行了详细的比较和分析，并对点火方式的经济性进行了计算和分析。     

循环流化床稀相区流动结构的实验研究

应用粒子动态分析仪，对方形管循环流化床的稳定段颗粒相的流动结构进行了实验研究。颗粒浓度呈中心稀，壁面附近浓，且边角效应明显；颗粒速度的垂直分量中心向上，壁面附近向下，水平分量则指出／向壁面和角落。颗粒浓度和速度分布特性证实了方形环核结构２的存在。颗粒相的湍流脉动量随着向壁面的靠近而降低，且表现出显著的各向异性特点。湍流相关脉动量在床中心大，边壁低，且在床的中心区域呈现出各向异性而在边壁区则表现了各     

Macroscopic modelling of fluid dynamics in large-scale circulating fluidized beds

Macroscopic (semi-empirical) models for fluid dynamics of circulating fluidized bed (CFB) units are presented, with emphasize on applications for conditions relevant to industrial units such as fluidized-bed combustors. In order to make a structured analysis of the models, the CFB unit is divided into 6 fluid dynamical zones, which have been shown to exhibit different fluid-dynamical behaviour (bottom bed, freeboard, exit zone, exit duct, cyclone and downcomer and particle seal). The paper summarizes the main basis and assumptions for each model together with major advantages and drawbacks. In addition, a practical example on how a selected set of these local models can be linked to an overall model of the fluid dynamics of the entire CFB loop is presented. It is shown that it is possible to reach good agreement between the overall model and experimental data from industrial units.     

循环流化床锅炉的原理与设计

根据循环流化床的原理和作者多年来的实践，分析了目前国内循环流化床锅炉存在的主要问题。指出：灰平衡是分析固体不完全燃烧热损失的基础，也是计算锅炉热平衡和热效率的关键数据之一。一台循环流化床锅炉设计和运行的成功取决于炉膛、分离器和回料器的设计。鉴于目前国内循环流化床锅炉中各种新型分离器工作现状，很有必要对采用旋风分离器的问题重新认识。此外，还对回料器、对流受热面的设计等，发表了看法。由于环保条例对锅炉和燃烧设备的排放作了限制，燃烧无烟煤循环流化床锅炉要达到SOx等排放标准还须深入研究。     

Experimental study on coal multi-generation in dual fluidized beds

An atmospheric test system of dual fluidized beds for coal multi-generation was built.One bubbling fluidized bedis for gasification and a circulating fluidized bed for combustion.The two beds are combined with two valves:one valve to send high temperature ash from combustion bed to the gasification bed and another valve to sendchar and ash from gasification bed to combustion bed.Experiments on Shenhua coal multi-generation were madeat temperatures from 1112 K to 1191 K in the dual fluidized beds.The temperatures of the combustor are stableand the char combustion efficiency is about 98%.Increasing air/coal ratio to the fluidized bed leads to theincrease of temperature and gasification efficiency.The maximum gasification efficiency is 36.7% and thecalorific value of fuel gas is 10.7 MJ/Nm3.The tar yield in this work is 1.5%,much lower than that of pyrolysis.Carbon conversion efficiency to fuel gas and flue gas is about 90%.     

An experimental study of the effect of pin fins on heat transfer in circulating fluidized beds

An experimental investigation was conducted to study the effect of pin fins on heat transfer in circulating fluidized beds. Experiments were conducted in a 100 mm i.d., 5.15 m tall CFB unit, initially with no fins and then with 16-pin and 32-pin fins. Each pin was 6.35 mm in diameter and 15 mm long. It was observed that, although the heat transfer coefficient decreases with the use of fins, the total heat transfer increases owing to the increase in surface area which the fins provide. The results of heat transfer for unfinned surface were compared with those of other workers and found to be in good agreement.     

循环流化床锅炉的大型化

综述了国内外 1 0 0MW以上大型循环流化床锅炉的发展概况。对循环流化床锅炉大型化带来的技术难点 ,如锅炉本体结构布置、分离器布置、辅机系统布置等进行了分析和总结。并且论述了在国产循环流化床锅炉的大型化过程中基础研究的重要性。最后 ,提出了自己的展望和建议     

双流化床生物质气化及CO2捕获的模拟

用Aspen Plus建立了双流化床气化和燃烧模型,对生物质在双流化床中气化及CaO吸收合成气中的CO2过程进行了模拟研究;探讨不同反应条件:气化温度、蒸汽与生物质的质量配比(S/B)以及CaO循环量与生物质的质量配比(Ca/B)对合成气成分的影响,为该类型工业反应器的研发提供了理论依据.模拟分析结果表明:气化温度低于700℃时,CaO能很好地吸收气化过程中产生的CO2并促进平衡反应向产氢方向进行;在温度为650℃及CaO作用下,S/B在0.6～1.7内对合成气成分的影响不大;CaO的加入能够有效地改善合成气的组成,合成气中氢气浓度能达到95％以上,氢气产量达到52 mol/kg.     

掺烧煤气对循环流化床锅炉的影响及设计对策

混烧煤气会对循环流化床锅炉产生一定的影响；循环流化床锅炉如要求混烧煤气，在整体设计中应当考虑工况的变化，并消除其带来的不良影响。     

Prediction of the heat flux profile on the furnace wall of circulating fluidized bed boilers

The purpose of this work is to investigate and develop a correlation for predicting the profile of heat flux on the crest of the membrane water wall tube along the height of circulating fluidized bed furnaces. The heat conduction equation for the tube was solved numerically under various operating conditions and furnace sizes. It was found that the temperature and heat flux profiles decreased rapidly in the region above the secondary air ports and then were found to be nearly constant. In addition, the heat flux increased as the Froude number increased or as the bed particle to the furnace diameter ratio decreased. The results were used to develop a correlation for predicting the heat flux profiles of the boilers having capacities from 12 MW_th to 165 MW_th in terms of dimensionless temperature, the Froude number, the diameter ratio and the height from the ports to the total height ratio.     

Investigations of pressure fluctuation history records of gas–solid fluidized beds

A transducer pressure probe is devised to measure the pressure‐history curves up to a maximum frequency of 200 Hz. It is installed on the wall of a 153 mm² fluidized bed and is employed to establish the solids mixing and movement pattern of an air fluidized bed comprising of glass beads of 2093 μm average diameter. The pressure variations recorded with a speed of about 11 Hz for a period of 92 s are employed to compute several statistical functions and analysed to infer the quality of fluidization. For the range of fluidization number 1.05–1.48, it is inferred that in this bubbling regime, the solids near the bed wall region descend down while the air bubbles drift to the central region and rise up in the fluidized bed. This bulk macroscopic hydrodynamic picture of solids movement is in conformity with the conclusions of other co‐workers. Copyright © 2000 John Wiley & Sons, Ltd.