低NOx燃烧器的煤质适应性研究

对低NOx燃烧器原理，燃烧初期NOx生成量与煤质挥发分的关系，空气分级燃烧技术对不同煤质所起的作用，以及低NOx燃烧器在我国电站锅炉的应用情况，低NOx燃烧器的煤质适应性进行了分析探讨。提出了低NOx燃烧器的研发和推广建议。     

低氮燃烧器改造及应注意的问题

介绍了对锅炉进行低氮燃烧器改造的设计思想、燃烧调试过程及运行中发生的问题,提出了今后低氮燃烧器改造中应改进的方向。实践表明:分级送风技术可以抑制NOx的生成,但主燃烧区过量空气系数的降低也会影响锅炉热效率,两者必须综合平衡地考虑。     

煤粉燃烧低NOx排放技术分析

详细分析了煤粉燃烧的特点及其燃烧产物NOx的生成机理,从实用性、高效性对目前各种控制煤粉燃烧NOx排放的技术(如低NOx煤粉燃烧器、空气分级、再燃等)进行了介绍,并结合运行实际情况进行了比较分析。     

新型超低NOx燃气燃烧器设计及数值模拟

国家"煤改气"政策实施以来,燃气锅炉的应用日渐广泛,开发和设计新型超低NO_x燃气燃烧器具有重要意义。介绍了烟气再循环、燃料分级燃烧以及旋流空气分级等低NO_x燃气燃烧技术,分析了新型燃气燃烧器燃烧过程中NO_x的生成机理和控制因素。通过数值方法,对一台新型燃气燃烧器的燃烧过程进行模拟,得到流场、温度场和NO_x浓度场等,发现燃烧火焰均匀分散地充满整个炉膛,没有局部高温区域,从而避免了NO_x的大量生成。根据计算,炉膛出口NO_x排放浓度为66mg/m~3,符合新型燃烧器超低NO_x排放的设计目标。     

300MW燃煤锅炉低氮氧化物燃烧的改造

采用空气分级燃烧技术对现役1025t/h国产SG-1025/16.7-M313UP型直流燃煤锅炉进行低氮氧化物（NOx）燃烧改造,保留原主燃烧区基本格局不变,在主燃烧器上方增加三层三维可摆动的分离布置燃尽风（separated over fired air,SOFA）,主燃烧器区域的二次风喷口面积相应减小,实现炉膛内的分级燃烧;一次风、二次风采用多切圆系统,实现风包粉格局,防止水冷壁高温腐蚀及结渣。改造后进行炉内空气动力场的冷态试验研究和热态调整,NOx排放的质量浓度为437.5mg/m^3,降低了48.55%,锅炉运行正常。     

600MW机组锅炉空气分级低NO_x燃烧数值模拟

某600MW机组四角切圆锅炉在满负荷运行方式下NOx排放浓度约400mg/m3,不能满足国家对电站锅炉NOx减排的要求。对此,采用高级复合式空气分级低NOx燃烧技术和炉膛布置相匹配的方法,降低NOx排放量。同时,以数值模拟软件FLUENT为工具,采用k-ε双方程模型,对燃烧器拟改进结构与原始结构锅炉煤粉燃烧过程和NOx生成特性进行模拟并对比。结果表明:采用空气分级燃烧后,炉膛温度场、速度场以及CO、O2的排放量均有相应的变化,且NOx排放量大大降低;数值模拟结果和试验结果的计算误差在5%以内,可准确预测燃烧器改进后NOx生成与排放量,为燃烧器的改造提供一定的理论依据。     

基于降低NO_x的超临界机组锅炉燃烧器优化改造

针对某超临界机组锅炉降低氮氧化物排放的要求,提出了低氮燃烧器改造方案。采用超浓缩煤粉燃烧与燃尽风摆动的立体错列分级低氮燃烧技术,将煤粉燃烧器改造为新型旋流耐磨陶瓷煤粉燃烧器,燃尽风燃烧器全部改造为上下摆动燃烧器,并对改造前后的锅炉试验数据进行比较,证明了优化改造后锅炉的氮氧化物有了大幅度降低。     

旋流式燃烧器

燃气灶具由多个部件组成,其中最重要的是燃烧器。近年来,随着燃气技术的进步,各种新型高效燃烧器不断涌现,旋流式燃烧器就是近年来新开发并被广泛采用的一种,现介绍如下: 一、结构与原理 与普通燃烧器不同,旋流式烧烧器在大孔板上有特殊设计,如图1。当燃气—空气混合气从倾斜的火孔流出燃烧时,就会产生一种特殊的旋流聚焦的火     

旋流燃烧器配燃尽风对NOx排放和燃尽率影响的试验研究

在西安交通大学1 MW热态煤粉燃烧试验炉上,采用2台双调风旋流燃烧器对冲燃烧,并在主燃烧器上方不同位置布置燃尽风(OFA),对神华优质烟煤、河津劣质烟煤、长治贫煤这3种煤进行了热态模化试验.结果表明:OFA燃烧器布置的相对位置,对NOx的生成和飞灰含碳量的影响较为显著,当OFA燃烧器与主燃烧器的相对位置由近向远布置时,3种煤的NOx生成量均先增加后减少,而飞灰合碳量先降低后增高;OFA空气分级燃烧技术,有利于高挥发分燃料降低NOx的生成和低挥发分燃料减少飞灰含碳量;只有合理地设计和布置OFA燃烧器,才能在降低NOx生成量的同时,尽量减少飞灰合碳量.     

热电联产机组锅炉深度空气分级技术应用

针对热电联产机组75 t/h燃煤锅炉氮氧化物排放浓度较高的问题,对其燃烧系统进行了WR浓淡燃烧器和深度空气分级即多层轴向空气分级和径向空气分级组合的技术改造,将燃烧二次风分为70%~85%和15%~30%的两部分分别送入炉膛,使炉内煤粉燃烧分为热解区、富氧区和贫氧区,以减少NOx的排放。结果表明,改造后锅炉NOx排放浓度降低了40%以上,而飞灰含碳量和炉渣含碳量无明显变化。     

一种中心风可调的直流燃烧器设想

针对电站锅炉燃煤特性变化范围大的实际,分析了现有燃烧器的稳燃机理及其对煤种的适应性,提出了研发一种中心风可调直流燃烧器的设想。设想通过中心风的调整,可使燃烧器的功能在钝体燃烧器与夹心风燃烧器间转换,以适用更大范围的煤种变化。     

Analysis on Frequent Flameout of HG- 1025/18.2- YM6 Boiler

Based on reason analyses for frequent flameout of HG- 1025/18.2-YM6 boiler in a given power plant after coal quality variation, major factors such as unreasonable burner structure and inappropriate secondary air distribution were discussed in detail. A new mode of secondary air distribution was introduced to optimize the combustion performance, and a lower burner was retrofitted by increasing the relative distance between the primary air fuel rich-lean nozzles and reducing the size of waist air nozzles as well. As a result, the recirculating zone became more stable and the burner＇s combustion stability was improved. Practical operation shows that the modifications are so effective that the flameout problems caused by instable combustion never occur in operation.     

Study of Sequential Two-Stage Combustion in a Low-Emission Gas Turbine Combustion Chamber

In this paper, we analyzed advanced ground-based power gas turbine units with low-emission combustion chambers used for consecutive two-stage fuel combustion. Such low-emission combustion chambers have a wide range of stable performance modes with reduced emission of harmful substances. The two-stage combustion chambers used in gas turbine units of various capacities—small (for example, M7A-03 with a capacity of approximately 8–10 MW), medium (L20A and L30A with a capacity of 18–30 MW) and large (9HA and GT36 with a capacity of over 300 MW)—showed their universality, efficiency, and good possibilities for scaling. The designs of low-emission combustion chambers for gas turbine units of different capacities are fundamentally similar. They consist of two sequentially located combustion volumes (stages), and each of them has its own burner unit. The first burner unit is typical for low-emission combustion chambers with the combustion of the premixed air-fuel mixture and consists of swirlers, mixing zone, fuel injectors, and igniters. The second burner unit is located downstream, and air-fuel mixtures of a different composition are supplied into it through special holes. The combustion of the mixtures occurs at a lower oxygen content and higher temperature. The ignition, work until idling, and loading before switching to the low-emission mode and switching to it are performed by the operation regulation of the first burner unit. Fuel in the second burner unit is supplied when a certain temperature of the gases arriving from the first combustion stage is achieved, which ensures its self-ignition. The further load is regulated by the fuel supply to the second burner unit. The design implementation of the sequential two-stage combustion scheme and approaches to regulating fuel and air distribution over the stages that ensures stable nonpulsating combustion are different and so they are of great scientific and practical interest.     

沙市电厂220 t/h锅炉燃烧优化控制装置与系统

电站锅炉一直用给粉机转速代替燃料量来调节主汽压力，但由于给粉机的分散性和非线性，使锅炉燃烧器出力不均，燃烧不稳定，用燃烧指导系统所测量的煤粉浓度和一次风流速计算入炉煤量，代替给粉机转速作为资料量可以实现燃烧器的均衡出力和锅炉的优化燃烧，文中介绍了这一系统的组成与原理，并在湖北沙市电厂用工控机组成的控制系统上进行了有益的尝试。     

一次风速度和煤粉质量浓度对等离子燃烧器一级燃烧筒点火特性的影响

为了研究一次风速度和煤粉质量浓度对等离子燃烧器一级燃烧筒点火特性的影响,建立了等离子燃烧器一级燃烧筒点火特性试验台。通过测量一级燃烧筒内煤粉火焰的温度,以及观察燃烧筒喷口煤粉火焰的稳定性,得到了煤粉质量浓度和一次风速度对点火特性的影响规律。试验表明:在燃用蒙南烟煤的情况下,等离子直接引燃煤粉过程中,挥发分的析出和着火比常规点火方式提前,煤粉燃烧的整体温度较高;当一次风速度为18m/s,要形成稳定的火焰,一级燃烧筒内的煤粉质量浓度不能低于0.15kg/kg。     

Studying the Aerodynamics of the TPP-210A Boiler Furnace When It Is Shifted to Operate with Dry-Ash Removal and Vortex Fuel Combustion

To reduce the amount of nitrogen oxide emissions and achieve more reliable operation of the TPP-210A boiler, a process arrangement for firing Grade TR Kuznetsk coal that involves using straight-flow burners and shifting the boiler from slag-tap to dry-ash removal is developed. Owing to a large burner downward slope angle and special arrangement of burners and nozzles, four large vertical vortices rotating in opposite directions are produced in the furnace lower part, as a result of which the combustion products dwell for a longer period of time in the burning zone and more complete fuel combustion is achieved. For verifying the operability and efficiency of the proposed combustion arrangement, investigations on a boiler furnace physical model were carried out using a technique for visualizing fuel jets and secondary and tertiary overfire air jets. The fuel jet temperature boundaries in the course of jet propagation in the furnace model are also determined. The study results have shown that staged fuel combustion will be set up with using the proposed arrangement of burners and nozzles. In addition, large vertical vortices produced in the furnace lower part will help to achieve more efficient use of the dry bottom hopper heating surfaces, due to which lower coal combustion product temperature in the furnace upper part and smaller content of combustible products in fly ash will be obtained. Owing to low values of air excess factor at the pulverized coal burner outlet and gradual admission of air into the vortex zone through a few nozzles with intense inner recirculation of combustion products to the jet initial section, staged combustion of pulverized coal and low nitrogen oxide emissions will be secured. Owing to expansion of fuel jets, a rapid growth of mass in the fuel jet is achieved, which is obtained both due to ejection of the jet itself and due to forced admission of hot fuel gases from other jets. Investigations carried out on the physical model have confirmed that the proposed combustion arrangement features high efficiency and that a low content of nitrogen oxides in flue gases is obtained.     

空气分级燃烧降低NO_x排放的实验研究

在煤粉燃烧一维热态实验炉上进行了不同煤种和不同细度的煤粉分级燃烧实验,通过改变分级风送入的位置、一次风过量空气系数、煤粉细度和富燃区燃烧温度等实验工况,以分析分级燃烧时各种因素对煤燃烧过程中NOx生成量的影响规律。     

全自动集成式油燃烧器的研究

本文论述了利用离心式机械雾化喷嘴构成集成式全自动段式燃油锅炉燃烧器的设计方法。在此燃烧器中，把机械、液压（供料）及电器三大部分有机的组合为一体发挥各自的优势，改善了系统的功能，提高了可靠性。并对机－液联动的燃料／风量配比控制器、自闭式二段喷嘴、用定压控制方法保证最佳雾化及用段式燃烧调节锅炉负荷等作了较详细的介绍。     

Influence of the technique for injection of flue gas and the configuration of the swirl burner throat on combustion of gaseous fuel and formation of nitrogen oxides in the flame

How the points at which the flue gas was injected into the swirl burner and the design of the burner outlet influence the formation and development of the flame in the submerged space, as well as the formation of nitrogen oxides in the combustion products, have been studied. The object under numerical investigation is the flame of the GMVI combined (oil/gas) burner swirl burner fitted with a convergent, biconical, cylindrical, or divergent throat at the burner outlet with individual supply of the air and injection of the gaseous fuel through tubing. The burners of two designs were investigated; they differ by the absence or presence of an inlet for individual injection of the flue gas. A technique for numerical simulation of the flame based on the CFD methods widely used in research of this kind underlies the study. Based on the summarized results of the numerical simulation of the processes that occur in jet flows, the specific features of the aerodynamic pattern of the flame have been established. It is shown that the flame can be conventionally divided into several sections over its length in all investigations. The lengths of each of the sections, as well as the form of the fields of axial velocity, temperatures, concentrations of the fuel, oxygen, and carbon and nitrogen oxides, are different and determined by the design features of the burner, the flow rates of the agent, and the compositions of the latter in the burner ducts as well as the configuration of the burner throat and the temperature of the environment. To what degree the burner throat configuration and the techniques for injection of the flue gas at different ambient temperatures influence the formation of nitrogen oxides has been established. It is shown that the supply of the recirculation of flue gas into the fuel injection zone enables a considerable reduction in the formation of nitrogen oxides in the flame combustion products. It has been established that the locations of the zones of intensive fuel burnout and generation of nitrogen oxides do not coincide over the flame length, and the ambient temperature has a significant impact on the combustion stability at low values and on the concentration of nitrogen oxides in the combustion products at high values.