发电厂锅炉空预器堵塞的原因及对策

发电厂锅炉空预器是利用锅炉尾部烟道的烟气热量加热进入锅炉空气,从而降低排烟损失,提高进风温度,提高锅炉效率的设备,如锅炉空预器发生堵塞将会严重影响锅炉的满负荷运行,因此,采取有效的预防措施避免空预器的堵塞至关重要,通过对发电厂锅炉空预器堵塞的原因进行探讨,找出引起堵塞的主要原因为蒸汽喷射压力低、风机进气温度低、排烟温度过高、预热器的金属面温度低以及煤质原因,在采取了强化原煤管理、防止空预器异常和正确设置空预器吹灰等有效的预防措施后,空预器的堵塞得到有效的控制。     

空气预热器进风温度变化时基于燃料高位和低位热值的锅炉排烟热损失计算

锅炉排烟热损失是评价燃煤火力发电厂技术经济性的关键,详细分析了利用烟气余热来提高空预器进风温度对锅炉排烟热损失的影响,给出了以燃料高位热值和低位热值为基准的各项排烟热损失计算公式。计算结果表明,空预器进风温度提高时,锅炉热效率增加,且以高位热值为基准和以低位热值为基准计算的排烟热损失与锅炉主机厂的性能计算结果一致,为空气预热器进风温度变化时锅炉排烟热损失的计算提供了可行的方法。     

四分仓回转式空预器一次风侧增加扇形板优化改造

针对某电厂2台300 MW裤衩腿型CFB锅炉机组运行过程中容易出现的偏床、厂用电率高、排烟温度高等问题,结合该厂空预器和一次风系统的现状,提出了将空预器五分仓改造、一次冷风和一次热风在进出空预器时各自分开布置,一次风机变频控制的改造方案。改造后在床压调整过程中,一次风机变频调节结合一次风机导叶调节,调节灵活,减少了偏床现象的发生。相比液偶调节,极大的降低了厂用电率,提高了空预器的换热效率,有利于锅炉的安全经济运行。     

热管式空预器及鳍片式省煤器在电厂中的应用

娘子关电厂3#炉由于运行时间较长,锅炉出现了尾部漏风严重,排烟温度较高,省煤器磨损和空预器腐蚀堵灰等问题.1999年大修中采用热管式空预器及鳍片式省煤器,取得了很好的运行效果.     

管式空预器热风再循环计算及防漏措施

为实施扬子热电厂大修期间省煤器和空预器的改造,保证锅炉在排烟温度降低的同时,不会因为环境温度过低而造成低温腐蚀严重,通过合理的酸露点和空预器最低壁温计算及热力校核计算再循环风量,证明了加装热风再循环的合理性.     

烟气余热利用在1000 MW机组中的应用研究

华能莱芜电厂6号机组为1000 MW超超临界二次再热机组,为提高机组效率,布置旁路省煤器,降低排烟温度。同时,配套布置烟气余热利用系统提高空气预热器(简称空预器)进风温度。该系统采用工质为水的闭式循环,从引风机出口烟气吸热,到空预器入口冷风放热。研究旁路省煤器和烟气余热利用投运和调节方法,烟气余热利用有暖风器和低温省煤器作用,可减少空预器因硫酸氢铵堵塞。又进行节能和投资回收年限分析,分析表明:采用烟气余热利用后发电煤耗降低1.86 g/kWh,节能效果显著。     

管式空预器热风再循环计算

在扬子热电厂大修期间省煤器和空预器改造中,为了保证锅炉在排烟温度降低的同时不会因为环境温度过低而造成低温腐蚀严重,采用了加装热风再循环的措施.通过合理的酸露点和空预器最低壁温的计算以及再循环风量的热力校核,证明了加装热风再循环的合理性.     

空预器排烟温度高的原因及解决措施

某电厂3#机组在试运行期间存在空预器排烟温度高于设计值的问题,影响了锅炉的安全经济运行。针对这一问题,进行深入分析,找出影响因素,并提出一系列解决措施,从一定程度上解决了排烟温度偏高的问题。     

复合相变换热器作为锅炉空预器的应用研究

在燃煤锅炉的各项热损失中,排烟热损失是最大的一项。一般的锅炉运行时排烟温度约在130～160℃,若能将其降低到110℃以下,锅炉效率将提高2%左右。锅炉尾部空预器部分长期存在漏风、低温腐蚀、堵塞及磨损等问题,一直是困扰锅炉业界的难题。随着复合相变换热器的问世,并辅之以纳米陶瓷涂层,排烟温度可以降至110℃以下,空预器漏风、腐蚀及堵塞问题也可得到很好地解决,     

燃煤机组空预器低温腐蚀解决方案浅析

  [目的]  空预器低温腐蚀危及电厂锅炉的运行安全,需要对解决燃煤机组空预器低温腐蚀的不同方案的技术特点进行分析比较。  [方法]  分析了空预器的低温腐蚀解决方案。通过技术分析、能耗分析对提高空预器冷端空气温度暖风器方案和热风再循环方案进行了技术探讨。  [结果]  暖风器方案和热风再循环方案在解决空预器的低温腐蚀问题上各有其技术特点,暖风器方案虽然设备初投资比较大,但其系统特点具有明显的优势。  [结论]  对于空预器的低温腐蚀问题,暖风器方案的适用性更广。     

直吹式制粉系统与空气预热器的质量能量平衡关系分析

1前言在现代煤粉锅炉中,制粉系统是锅炉设备最重要的辅助系统之一。直吹式制粉系统与锅炉设备的联系尤为密切,直吹式制粉系统的运行条件不但影响进入锅炉炉膛的热量大小和燃料进入炉膛的着火燃烧条件,而且还会影响流经空气预热器的空气量和出口热空气温度,导致空气预热器在尾部     

热管空气预热器应用研究

热管空气预热器是一种重要的余热回收装置。它可以有效减轻锅炉的低温腐蚀,降低排烟温度,提高锅炉效率。针对某电厂锅炉热管空气预热器,进行了壁温等参数测试。结果表明,该炉加装前置式热管预热器后,排烟损失降低1.41%,锅炉效率提高1.24%。从热管空气预热器的传热特性、阻力特性、等温特性、管壁温度特性及漏风情况看,热管的设计、热管的制造和热管的安装都是成功的。     

提高YJP-Q系列车用液体加热器热效率的试验研究

为提高车用液体加热器的热效率,设计了双水腔换热器和双面燃气加热换热器。经台架试验,二者的热效率比原机有大幅提高,而排气温度大幅下降;还对燃烧室燃气回流罩位置及水流量对加热器热效率的影响进行了试验研究。     

煤气锅炉低压省煤器与煤气加热器比较

目前国内钢铁企业的煤气余能发电工程通常采用煤气加热器或凝结水低压省煤器降低锅炉排烟温度,提高锅炉效率。从理论结合实际的角度对低压省煤器及煤气加热器两种方案进行主要的经济技术对比,并提出相应系统优化方案。     

Performance simulation of a low‐swirl burner for a Stirling engine

A new type of gas burner for Stirling engine that can recover adequate heat from exhaust gas was designed based on the plate heat exchanger and low‐swirl combustion technology, which consists of three components: a cyclone, a burner, and a circular plate heat exchanger. The circular plate heat exchanger tightly wound around the combustion chamber plays a high efficiency of heat recovery role. In consideration of the radial symmetry of the burner, a three‐dimensional numerical simulation was carried out by Ansys15. The velocity distribution, temperature distribution, and pressure distribution of the combustion gas were presented respectively. Strong backflow that came from the exhaust gas around the root of the flame in the combustion chamber and a vortex below the inlet of the exhaust gas channel were found, which were beneficial for the combustion and improving the uniformity of temperature distribution. Combustion behaviors of the burner under standard operating conditions were obtained, the highest temperature was about 2200 K in burner and the exhaust gas entered the plate heat exchanger at the temperature of 1375 K and exited at 464 K, with the waste heat recovery efficiency over 65.8%. And, the air‐fuel ratio and combustion power had negligible effect on the waste heat recovery efficiency.     

相变换热技术在水套加热炉节能改造上的应用

本文介绍了用相变换热技术改造水套加热炉的原理和方法，对改造前后水套加热炉的排烟温度、热效率和燃气耗量等指标进行了测试和分析，并对改造前后水套加热炉的经济性进行了对比。     

CFD modeling of a radiant tube heater

This paper reports experimental and Computational Fluid Dynamics (CFD) studies on combustion and radiation heat transfer from a real radiant tube heater. The temperature along the radiant tube as well as at different positions in a test room has been measured. A good agreement between the experimental and predicted results has been found. Based on this validation, the effect of excess air, presented by Air Factor (AF) on efficiency of heater has been studied, theoretically. Moreover, the effect of inlet air preheating on heater efficiency has been examined. The results show that the higher values of excess air can reduce the heater efficiency. The air preheating temperature caused positive effect on heater efficiency. In addition, the results show at higher preheating temperature the effect of AF value on heater efficiency is negligible.     

热回收式CO2制冷系统性能研究

对热回收式CO2制冷系统性能COP进行了计算和分析,结果表明:蒸发温度、气体冷却器出口CO2温度、热水加热器入口水温是影响其COP的主要因素;回热器出口过热度对COP的影响较小,对压缩机的排气温度影响较大;随着排气压力的升高,COP是否出现峰值,取决于气体冷却器入口制冷剂的特征温度;在相同工况下,蒸发温度、气体冷却器出口CO2温度、回热器出口过热度对最佳排气压力的影响较小,热水加热器入口水温是影响最佳排气压力的主要因素。     

Unsteady thermal flow analysis in a heat regenerator with spherical particles

Heat regenerator occupied by regenerative materials improves thermal efficiency of regenerative combustion system through the recovery of sensible heat of exhaust gases. By using one-dimensional two-phase fluid dynamics model, the unsteady thermal flow of regenerator with spherical particles, were numerically analysed to evaluate the heat transfer and pressure drop and to suggest the parameter for designing heat regenerator. It takes about 7 h for the steady state in the thermal flow of regenerator, where heat absorption of regenerative particle is concurrent with heat desorption. The regenerative particle experiences small temperature fluctuation below 10 K during the reversing process. The thermal flow in heat regenerator varies with inlet velocity of exhaust gas and air, configuration of regenerator and diameter of regenerative particle. As the gas velocity increases with decreasing the cross-sectional area of the regenerator, the heat transfer between gas and particle enhances and pressure losses increase. As particle diameter decreases, the air is preheated higher and the exhaust gases are cooled lower with the increase of pressure losses. At the same exhaust gases temperature at the regenerator outlet, the regenerator length need to be linearly increased with inlet Reynolds number of exhaust gases. It is confirmed that inlet Reynolds number of exhaust gases should be introduced as a regenerator design parameter. Copyright © 2002 John Wiley & Sons, Ltd.     

柴油客车废气余热式采暖装置的研究现状

介绍了客车采暖装置的方式及特点，重点对我国柴油客车废气余热式采暖装置在基础理论、结构设计、应用方面的研究和发展现状进行分析，指出存在的主要问题及解决措施。