新型煤粉燃烧器冷态流场特性和热态实验

对端面旋流进风结构的新型煤粉燃烧器进行了冷态流场特性和热态中试实验。冷态实验结果表明：端面旋流进风结构能获得对称、均匀的流场，燃烧器的进、出口结构对燃烧器内压力场和流场分布影响很大；出口直径的大小决定中心回流区域的大小；环形叶片进口位置的变化对燃烧器内流场的影响集中在燃烧器头部。热态实验表明，当煤粉粒径小于0．2mm时，燃烧器内温度可达1600℃，能实现顺利排渣，系统运行可靠。     

扩散燃烧流场测量的PIV应用研究

为了研究燃烧火焰结构及其内部流动状况，考察其在燃烧喷嘴前回流区冷态试验模拟中和实际燃烧状况下的差别，利用二维粒子成像速度仪(PIV)对带钝体燃烧器中的丙烷／空气扩散燃烧的流场进行了测量，实现了火焰内部流动的可视化．通过对热态流场与相应冷态流场的对比分析表明，在复杂燃烧中冷态流场模拟与实际燃烧过程中的流动存在较大差别，实际燃烧中的流动状况变得紊乱，回流区在长度和宽度上都明显增大．     

Study on Flow Characteristics of Bluff-body Stabilized Turbulent Premixed Flames

采用粒子图像测速技术对钝体燃烧器出口下游流场进行了测量,比较分析了冷、热态流动结构以及速度对流场特性的影响.结果表明：钝体燃烧器冷、热态流动特性具有明显差异：冷态流场属于环流主导型,中心轴线上有前、后两个滞止点;而热态流场表现为射流主导型结构,并且随着中心射流流速的增大射流的主导作用增大,中心轴线上没有出现滞止点,并且中心轴线上速度最小值随着中心射流流速增大而减小且接近燃烧器出口,随着速度比的增大而增大且远离燃烧器出口;冷态条件下靠近燃烧器出口处湍动能较大,热态条件下燃烧器下游的湍动能较大,速度较高的工况具有较大的湍动能.     

220t_h锅炉冷态数值试验研究

针对锅炉传统冷、热态性能试验存在的局限性,以220t／h四角切圆燃烧锅炉为原型．建立其可实现的k-ε数学模型,结合锅炉冷态性能试验,利用计算流体力学软件Fluent模拟炉内空气动力场。数值模拟结果与冷态试验结果的基本一致性和两种结果分布趋势的较好吻合性说明该数值模拟方法能较好地反映炉内真实的流场特性,验证了所建数学模型的正确性及可靠性,为进一步完善锅炉冷态性能试验和进行热态数值试验提供更全面的数据信息。     

利用一维热膜探针对旋流燃烧器出口冷态旋流流场的测量

测量了在不同偏航角α、俯仰角θ及风速下一维热膜探针偏航系数ｋ和俯仰系数ｈ的数值,研究了其变化规律,并利用一维热膜探针对空间气流的方向敏感性对径向浓淡旋流煤粉燃烧器模型出口的冷态旋流流场进行测量。确定了气流湍流脉动水平较高,有利于煤粉燃烧的区域。     

丙烷/空气扩散火焰流场的PIV试验研究

为了研究燃烧火焰结构及其内部流动特征,利用粒子成像速度仪(PIV)对丙烷/空气扩散燃烧的流场进行了测量。并进行了冷、热态流场的对比,结果分析表明:热态回流区的速度明显的增大,回流区中心位置稍偏下,速度梯度大,更紊乱,并且沿轴向速度衰减慢。     

改进型液排渣煤粉燃烧器实验研究

对传统的液排渣型锅炉煤粉燃烧器进行了优化设计,并用五孔探针对改进后的燃烧室流场进行了冷态试验研究,测定了空气动力场特性。并对不同配风参数进行了热态实验,测量了室内温度场分布。试验表明,燃烧室有较高的燃烧强度和灰渣溶化率。该燃烧室内的温度水平基本达到国外同类设备水平。这些为液排渣锅炉煤粉燃烧器设计的进一步完善和工业试验提供了基础。     

带中心管和多级切向进风的燃煤涡旋燃烧炉

对具有中心管多级发向进展结构的新型燃煤涡旋燃烧炉的冷态流动与混合特性及煤燃烧特性分别进行了冷，热态实验或数值模拟，冷态实验给出包括中心管在内的整个炉内流场的速度分布。冷态实验和数值模拟还给出分级喷入的二次风在炉内的混合特性，热态实验证实涡旋燃烧炉在较大的热负荷变化范围均具有较高煤粉燃烧效率，ＮＯＸ排放量可控制在一定范围以内，炉内的温度水平可保证固态排渣的实现。     

SG—1025t／h直流锅炉燃烧器及反向切圆布置的试验与改造

常熟发电厂ＳＧ－１０２５／１６．７－Ｍ３１８型锅炉在运行顺在燃烧器烧坏及炉膛严重结渣、炉膛出口烟温偏差等问题，通过冷、热态诊断试验和对改造方案的冷态模拟试验的验证，对燃烧器结构、布置方式进行了改造，最后通过冷、热态性能与运行优化调试，取得了良好的效果，消除了原来存在的问题，进一步提高了锅炉运行的经济性和安全可靠性。     

内嵌逆流柱形风帽的冷态模化试验和三维流场的数值模拟

对内嵌逆流柱形风帽进行了冷态模化实验,根据相似理论由冷态试验参数推导出热态运行参数,为循环流化床锅炉设计提供依据。采用RNGk-ε湍流模型对风帽内部流场进行数值模拟,揭示了风帽内部阻力分布情况,为风帽优化设计提供依据。     

Numerical prediction and practical improvement of pulverized coal combustion in blast furnace

The burning characteristics of pulverized coal in blowpipe and tuyere at two different injection patterns are simulated numerically, to aid improving the practical performance of blast furnace. With the condition of the same fuel and oxidant mass flow rates, the predictions indicate that the combustion efficiency of pulverized coal using double-lance can be substantially enhanced compared with that using single lance. Accordingly, the pulverized coal injection in a practical blast furnace was modified from single lance to double-lance. As a result, the practical injection rate of the pulverized coal in the blast furnace was increased from 110 to 153 kg/tHM, revealing that a profound decrease in operating cost of the blast furnace has been implemented.     

Fundamentals of coal combustion during injection into a blast furnace

The efficiency of coal combustion is important for the blast furnace process. Incomplete combustion of coal does not reduce coke consumption as can be expected and decreases burden permeability which results in improper gas flow and temperature distribution. Consequently, this reduces the throughput of the blast furnace.

This paper describes combustion conditions and mechanisms of coal combustion in the blast furnace, and discusses factors affecting coal combustion such as injector location, coal type, injection rate, maceral composition, and air blast parameters. Also, mathematical models of coal and coal/coke combustion in the blast furnace are considered.     

300MW高炉煤气与煤粉混燃锅炉热力特性及经济性分析

针对高炉煤气与煤粉混燃易发生过（再）热器超温、飞灰含碳量高等问题,对某300MW机组四角切圆高炉煤气／煤粉混燃锅炉进行了热力特性计算,并对掺烧高炉煤气后机组的经济性进行了分析．结果表明：掺烧高炉煤气后炉内温度降低,烟气量增加,辐射吸热量减少而对流吸热量增加,炉膛出口烟温及其后受热面区域的烟温升高,排烟温度升高,锅炉效率降低;掺烧高炉煤气后厂用电率有所升高,但发电煤耗降低,使发电成本降低．     

Acoustic energy measurements in a coal-burning Rijke-tube combustor

Acoustic energy measurements were carried out in a coal-burning Rijke combustor using a hot-wire anemometer probe and a furnace microphone probe. The acoustic power output of the combustion region was found to increase with the coal-bed thickness. A minimum coal-bed thickness was found to be necessary for sustaining the acoustic oscillations, and it was found that stable operation was not possible for large coal-bed thicknesses. Substantial acoustic power was found to be lost from the tube ends. Measured tube-end impedances were found to be dependent on the coal-bed thickness, and were of a magnitude consistent with the authors' expectations in earlier work. A phase difference was found to exist between the unsteady heat release and the pressure oscillation in the combustion zone. This result is also consistent with criteria derived in the authors' earlier theoretical work. The amplitude of the unsteady heat release as a fraction of the steady heat release was obtained as a function of the bed thickness.     

Control of ash related problems in a large scale tangentially fired boiler using CFD modelling

The objective of this study is to develop a three-dimensional combustor model for predicting the performance of full-scale tangential fired (TF) boiler and to determine the flow patterns of the gas and coal particles, with an emphasis on formation mechanism of gas flow deviations and uneven temperature on the super-heaters, re-heaters and divisional super-heater sections of the furnace. The importance of these simulations is to identify the locations of optimum additive injection ports to achieve maximum impact of additives in the combustion process to minimize the temperature deviation and reduce ash-related issues. This study is a classic example of numerical investigation into the problem of turbulent reacting flows in large scale furnaces employed in thermal power plants for the remediation of ash deposition problems. Present work also provides an investigation of the influence of number of tripped burners on the characteristics of the flow and thermal fields. Excellent agreement between the simulation results and key boiler design values and available site operation records following full-scale trials indicate that the calculations are reliable. The results obtained from the present work are directly relevant to coal-fired utilities for not only demonstrating the effectiveness of computational fluid dynamics (CFD) based tools in combating operational issues but also provides an alternative to conventional remediation strategies.     

The generation of high temperature gas from fluidized bed furnaces

The work described relates to the development of a coal-fired fluidized bed furnace for the generation of hot gases for industrial heating processes. Following a programme of coal model studies of the internal solids circulation rates between adjacent beds, a furnace test facility was developed in the form of two interconnected fluidized beds. One bed is operated as a partial gasifier/pyrolyser and the other as a char combustor. The gas produced by pyrolysis is mixed above the bed with the oxygen-rich gas from the char combustor and burns to give hot gas at temperatures of up to 1600°C. The use of low ash washed singles grade coal (13–25 mm size range) gives an overall combustion efficiency better than 98 per cent.     

准东煤掺烧煤矸石安全性与经济性分析

高岭土与低钠煤可以有效抑制燃用准东煤时炉内的沾污结渣问题,但由于其价格升高,为降低电厂燃煤成本,因此提出将煤灰成分相似的煤矸石作为准东煤防结渣添加剂。分析煤矸石作为添加剂抑制炉内沾污结渣的可行性,根据入炉煤灰中折算Na₂O含量低于3.0%,确定掺烧比例,并在某150 MW机组上进行实炉掺烧试验。通过掺烧试验分析可见,煤矸石掺烧比例不宜过大,否则煤粉细度变粗,入炉煤热量降低,影响锅炉带负荷能力;掺烧煤矸石锅炉能够安全稳定运行,并可有效抑制炉内结渣,同时还可节约标煤,为电厂带来一定经济效益。     

镇海发电厂DG 670/140-8型煤粉锅炉灭火原因分析

由于电厂实际燃用煤种和设计煤种差距较大,使电厂的安全经济运行受到影响.镇海发电厂一台DG 670/140-8锅炉在2005年7月12日发生的一次熄火事故,指出原因在于煤种与炉型的严重不匹配,造成2号角上一次风管内发生爆燃,并产生一次风管堵管的假象.爆燃产生的冲击波将一次风管内的煤粉迅速推入炉膛,产生二次爆燃,二次爆燃产生的冲击波将2号角燃烧器及下层燃烧器首先全部扑灭,造成锅炉负压灭火,从而较好地解释了事故原因.     

混煤燃烧特性的实验研究

选择武钢高炉混煤喷吹的某种烟煤和某种无烟煤为研究的煤源,对不同混合比例的混煤燃烧进行了实验研究。利用差热天平的TG—DTG—DTA热分析,探讨了烟煤不同掺混比对混煤的燃烧特性的影响规律和合适的烟煤掺混比例,阐明了烟煤掺混高炉喷煤技术经济指标的改善作用。