CFB锅炉防磨梁改造及运行效果分析

对UG-260/9.8-M2型高温高压循环流化床锅炉防磨梁改造前后的运行数据、综合能耗及停炉检查情况进行了对比分析.改造后的防磨效果是明显的,达到了预期的目的,可大大延长锅炉的运行周期.     

CFB锅炉防磨技改工程

我厂2×35 t/h CFB锅炉受热面磨损严重,低温过热器及省煤器的频繁泄漏、爆管事故长期困扰热电厂锅炉的安全、经济运行,降低热电厂开车率。 为减缓锅炉受热面管壁的磨损,延长受热面寿命,根据CFB锅炉受热面磨损机理,采用主动与被动两种的防磨措施,降低受热面磨损速度,延长电厂锅炉的运行周期,达到热电厂安全、经济、稳定运行的目的。 所谓主动措施系指通过改进不合理结构,降低烟气流速,降低烟气含尘浓度等措施。这是降低受热     

多级防磨梁在循环流化床锅炉上的应用

国宏公司热电车间自2007年3月1#、2#CFB锅炉陆续投运以来,受热面磨损严重,水冷壁爆管事故频发。针对水冷壁等磨损严重问题采取了一系列的防磨措施和技术改造,运用多级防磨粱后,结合传统的防磨措施,在实践应用中取得了良好的效果,大大减少了锅炉因磨损造成的运行故障,为热电厂带来了经济效益,在同类型循环流化床锅炉运行中有很好的借鉴作用。     

紧凑型CFB锅炉安装防磨梁存在的问题及解决对策

中石化镇海炼化公司紧凑型CFB锅炉存在水冷壁磨损严重的问题,安装多阶防磨梁装置（专利技术）后,取得了良好的防磨效果,但床温等运行参数发生了改变,经调整后床温降低,热经济性明显提高,保证了锅炉安全稳定、经济运行。     

CFB锅炉防磨技改新措施

CFB锅炉（循环流化床锅炉）的前身是沸腾炉,它是在沸腾炉的基础上加以物料返回系统,使未燃尽的燃料返回到炉膛内重复进行燃烧,提高了燃料的利用率.CFB锅炉因其具有煤种适应广、负荷易控制、燃烧强度大、炉内传热能力强、有利于环境保护等优点,近些年得到了广泛的应用与推广.但是由于锅炉用煤为颗粒状,水冷壁在这些颗粒的高速冲刷下受到严重的磨损,管壁会因此变薄而造成泄漏甚至爆管,因此防磨问题已经成为影响CFB锅炉正常运行的大问题.     

循环流化床锅炉防磨梁设计加装不合理及处理措施

1设计加装防磨梁山东兖矿国泰化工有限公司3#锅炉为UG．260／9．8-M2型循环流化床锅炉。锅炉于2006年12月6日投运,截至2010年9月19日锅炉停炉检修以加装防磨梁时已共计运行19000h。     

循环流化床锅炉水冷壁防磨技术研究与应用

循环流化床锅炉炉内受高浓度床料冲刷、磨损影响,水冷壁管壁厚减薄,泄漏或爆管事件频繁发生。防磨梁技术是目前循环流化床锅炉采取的一种主动防磨措施,保证锅炉长周期安全稳定运行,同时延长了炉内喷涂防磨周期,综合效益突出。     

杭锦发电厂燃用煤矸石CFB锅炉的优化设计

杭锦煤矸石2×300MW机组工程项目的锅炉设备系上海锅炉厂自主研发设计的首台300MWCFB锅炉。本文重点介绍了上海锅炉厂在本工程CFB锅炉的设计优化方案,特别是受热面优化布置和燃用煤矸石所采取的防磨措施。着实反映出国产300MWCFB锅炉设计研发的科学性和可靠性。     

循环流化床锅炉磨损及防磨方法探讨

从循环流化床锅炉磨损机理入手分析,根据循环流化床锅炉各部位结构特点,结合停炉检查情况,找出磨损部位及相应防磨方法。通过一定防磨实践以期提高CFB的耐磨性能,保证CFB锅炉的长周期安全运行,减少检修工作量和开停炉。     

循环流化床锅炉水冷壁磨损原因及防治

针对循环流化床锅炉水冷壁的磨损现状,先后采用金属热喷涂技术与防磨梁技术对水冷壁的磨损进行修复,通过对修复效果进行综合比较,初步认定防磨梁技术效果更好,能够更好地延长锅炉的连续运行周期。     

Heat flux profile of the furnace wall of a 300 MWe CFB boiler

It is important to properly understand and calculate the distributions of the heat flux and the heat transfer coefficient in a furnace for designing a circulating fluidized bed (CFB) boiler, especially for one with supercritical parameters. An experimental study of the heat transfer in a commercial 300 MWe CFB boiler was conducted in this work. The heat flux from the bed to the waterwall was measured by a heat flux meter at four different heights. The influence of suspension density and bed temperature was analyzed by measuring the pressure profile and temperature profile in the furnace. In addition a numerical modeling study on the two phase flow in the furnace was carried out. The results indicate that the density of the solids suspension was non-uniform in the cross section at a certain height, and decreased gradually with increasing furnace height. Consequently, the distribution of heat flux in the horizontal plane was non-uniform and decreased along the height of the furnace. The heat flux showed a decreasing trend near the center.     

300 MW CFB锅炉余热利用系统研究

针对某电厂300 MW CFB锅炉排烟温度较高的问题,通过在锅炉尾部烟道内布置低压省煤器,来降低排烟温度,同时可提高机组热经济性。根据低压省煤器系统的设计原则及参数要求,考虑排烟温度降幅受受热面低温腐蚀、管壁磨损、回热系统级间焓升约束等因素的影响,提出布置方案,并采用等效焓降法对方案的热经济性进行分析。计算结果表明,采用方案3机组热经济性较高,额定负荷下,煤耗可降低1.517 g/k Wh。布置低压省煤器后,节能效果显著,可为同类型机组的节能降耗改造提供参考和依据。     

Local temperature and wall radiant heat flux measurements in an industrial scale coal fired boiler

This paper reports measurements of local gas temperatures and wall incident radiant heat flux in an 80 MW_e pulverized coal corner fired boiler. Spatially resolved gas temperatures were measured using a 4 m long, triply-shielded suction pyrometer and total wall radiation was determined with an ellipsoidal radiometer. The data include detailed wall radiant heat flux measurements made around the periphery of the boiler at six different elevations. Local gas temperature profiles were measured at four axial positions in the boiler, with special attention to the near-burner region. Boiler operational data and coal proximate, ultimate and particle size analyses are also reported. Local gas temperatures in the boiler reached a maximum of nearly 1800 K near the burners and decayed to 1250 K at a position just above the boiler nose. In the burner plane gas temperatures varied from 600 K near the wall to 1800 K at the centre of the flame. Wall incident radiant heat fluxes varied between 440 kW m^{− 2} in the near-burner region to 100 kW m^{− 2} near the boiler nose. The radiation transport to the wall was observed to vary substantially around the periphery of the boiler, especially in the near-burner regions.     

非均匀热通量对热电器件性能的影响

提高冷热两端温度是提高热电器件发电效率的有效途径之一。但当施加于热端表面的热通量不均匀时,热端表面温度不均匀,系统性能受到影响。基于此,建立了热电器件的热电转换耦合数学模型,分析热电材料物性参数,非均匀热通量等参数对热电器件的功率输出特性的影响。数值模拟结果表明:材料物性参数随温度的变化对系统输出功率的影响不可忽略,热通量4 W·cm^-2时物性参数对系统最高温度的影响接近4%;非均匀热通量对热电器件输出特性影响也十分显著,热通量均匀度越小,热端表面温度分布不均匀性越大,极值温度越高,高温区越小,断路电压越低。     

CFB掺烧多样煤种的安全经济性分析

为进一步降低发电成本,全面提高电厂的经济效益,针对茂名石化乙烯煤代油技改项目2×410t/hCFB锅炉的特性,以及锅炉在燃用多样煤种所表现出来的技术特点。通过对不同煤种的特性进行分析论证,提出了合理的配烧方式以及在掺配过程中所采用的相应措施。     

An investigation of the heat transfer behavior of longitudinal finned membrane water wall tubes in circulating fluidized bed boilers

Experiments were conducted in a cold model circulating fluidized bed (CFB) having riser cross sectional area of 100 mm × 100 mm, height of 4.8 m, bed temperature of 75°C and superficial velocity of 8 ms^− 1. Local sand having average diameter of 231 μm, particle density of 2774 kg m^− 3 and bulk density of 1515 kg m^− 3 was used as bed material. The experiments were conducted for three tube configurations: a membrane tube, a membrane tube with a longitudinal fin at the tube crest and a membrane tube with two longitudinal fins at 45° on both sides of the tube crest. Heat transfer, heat transfer coefficient ratio and heat transfer ratio of the three tubes are presented as a function of cross sectional average suspension density. The results show that membrane tubes with one and two longitudinal fins have higher heat transfer than membrane tubes although they have lower heat transfer coefficient. In addition, numerical simulations were conducted to investigate the heat transfer behavior of the three tubes under the normal operating conditions of CFB boilers. It was found that the membrane tube with two longitudinal fins at 45° on both sides of the tube crest had the flattest inner wall tube heat flux profile. Moreover, in terms of temperature distribution in the tube material, it has the lowest profile.     

High density and high solids flux CFB risers for steam gasification of solids fuels

The application of high density and high solids flux CFB risers for steam gasification of solids fuels like coal and biomass has been examined in this paper. A simple mass and energy balance analysis revealed that a steam gasification riser needed to be operated at high solids fluxes in order to supply sufficient heat from the standpipe by circulating hot solids to the endothermic gasification reactor. The important design considerations to achieve high solids circulation rate in the CFB unit were discussed in this paper with emphasis given to the riser height, solids inventory, standpipe to riser diameter ratio, and solids feeding control device.     

Identification of local heat flux to membrane water-walls in steam boilers

A heat flux entering steam generating tubes in power station boilers may be a critical factor in considering the safety of the tubes. The knowledge of the distribution and magnitude of this flux during the operation of the power boiler is very important. The design of a modern boiler furnace requires the computation of furnace wall metal temperatures for the proper selection of the tube thickness and material. These temperatures are functions of the heat fluxes and the internal heat transfer coefficients. In this study, a measuring device (flux-tube) and a numerical method for determining the heat flux in boiler furnaces, based on experimentally acquired interior tube temperatures, are presented. An inverse method was developed, which can estimate the following parameters: the absorbed heat flux, the heat transfer coefficient on the inner tube surface and the temperature of water-steam mixture from temperature measurements at several interior locations of the flux-tube. The least squares method was used to minimize the differences between the calculated and measured temperatures. The unknown parameters are found using the Levenberg-Marquardt method. The number of temperature sensors (thermocouples) is greater than three because the additional information can help in more accurate estimations of the unknown parameters. The temperature dependent thermal conductivity of the flux-tube material was assumed. The developed flux-tube can work for a long time in the destructive high temperature atmosphere of a coal-fired boiler.     

Lateral flux and velocity of FCC particles in a CFB riser

The radial profiles of the lateral solids mass flux and the lateral solids velocity were determined for FCC particles in a 7 m tall circulating fluidtzed bed riser 0.14 m in diameter by applying a lateral flux probe and electrical capacitance tomography. The external solids mass flux was varied between 148 and 302 kg/(m².s), while the superficial gas velocity was varied between 3.7 and 4.7 m/s. Under these conditions, a dense bottom region and an upper dilute region coexisted in the riser. Lateral fluxes in the dense bottom region reached 100 kg/(m².s) at the wall, but fell to 14 kg/(m².s) at the wall in the upper dilute region. At both axial locations, a net deposition of solids from the core to the annulus occurred, indicating that fully developed flow was never established under these conditions. The lateral fluxes in the bottom region were significantly larger than those found in previous studies. It was further concluded that considering the lateral solids flux to be only a function of solids concentration is an over‐simplification.