Computational Modelling of Retrofitting a Coal Fired Boiler Type OP-230 for Predicting NO_X Reduction

This study focuses on a CFD modelling of biomass-derived syngas co-firing with coal in an older mid-sized PC-fired boiler of type OP-230 with low-emission burners on the front wall. The simulations were performed to determine whether the boiler can be retrofitted for the fulfilment of the prospective environmental protection regulations relating to levels of NO_X emissions. The improvement of the air staging via the dual-fuel technique was based on the indirect co-firing technology. The impact of two arrangements of dedicated syngas nozzles(below and above the existing coal burners), two syngas compositions and two heat replacements(5% and 15%) on the course of thermal processes in a furnace was tested. The reductions in NO_X emissions were predicted relative to the baseline when only coal is combusted. The highest reduction of about 38% was achieved with the syngas nozzles below the existing coal burners and 15% heat replacement. This arrangement of nozzles offers the residence time sufficient to co-fire coal with waste derived syngas. A lower reduction in NO_X emissions was obtained with the nozzles above the burners as the enlargement of local fuel rich zone near syngas injection becomes significant for 15% heat replacement. Results provide for the decreasing impact of methane content along with the increase of syngas heat input. The avoided CO_2 emissions through the syngas indirect co-firing with coal in the boiler are linear function of heat replacements.     

Experimental study on combustion characteristics and NO<Subscript>X</Subscript> emissions of pulverized anthracite preheated by circulating fluidized bed

A 30 kW bench-scale rig of pulverized anthracite combustion preheated by a circulating fluidized bed(CFB)was developed.The CFB riser has a diameter of 90 mm and a height of 1,500 mm.The down-fired combustion chamber(DFCC)has a diameter of 260 mm and a height of 3,000 mm.Combustion experiments were carried out using pulverized anthracite with 6.74%volatile content.This low volatile coal is difficult to ignite and burn out.Therefore,it requires longer burnout time and higher combustion temperature,which results in larger NOX emis-sions.In the current study,important factors that influence the combustion characteristics and NOX emissions were investigated such as excess air ratio,air ratio in the reducing zone,and fuel residence time in the reducing zone.Pulverized anthracite can be quickly preheated up to 800℃in CFB when the primary air is 24% of theoretical air for combustion,and the temperature profile is uniform in DFCC.The combustion efficiency is 94.2%,which is competitive with other anthracite combustion technologies.When the excess air ratio ranges from 1.26 to 1.67,the coal-N conversion ratio is less than 32%and the NOX emission concentration is less than 371 mg/m 3(@6%O2).When the air ratio in the reducing zone is 0.12,the NOX concentration is 221 mg/m 3(@6%O2),and the coal-N conversion ratio is 21%,which is much lower than that of other boilers.     

某电厂一期600 MW燃煤机组锅炉运行性能分析

介绍内蒙古大唐托克托发电厂#1、#2燃煤发电机组锅炉整体及运行性能。     

SZS型煤粉工业锅炉的结焦原因与防治措施

结焦对锅炉的经济安全运行有较大危害,通过对影响煤粉工业锅炉结焦原因的分析,结合运行实际,总结了锅炉系统完善设计的建议以及实际运行中预防结焦的措施,取得了较好的效果.     

燃煤锅炉NOx排放特性及其燃烧优化

锅炉燃烧优化通常是降低NOx排放的首选方法.对某厂410 t/h锅炉NOx排放进行了试验研究,特别是锅炉运行参数对锅炉效率和NOx排放量的影响进行分析.提出在现行条件下,通过燃烧优化提高锅炉效率,减少NOx的排放方法.     

浅析江联公司对甘蔗渣锅炉的开发设计

文章介绍了28t/h、40t/h燃蔗渣锅炉的设计思路、结构特点、汽水流程特点、冷热风管道系统,锅炉验收成功也标志着江联公司的设计制造技术及IS09001质量管理水平达到了较高的国际水准.     

一种燃蜂窝型煤锅炉的现状及改进

文章详细介绍了一种燃蜂窝型煤锅炉的现状及待改进的问题,针对型煤的燃烧速度慢、出力不足、不易大型化、燃型煤蒸汽锅炉的间歇用汽问题、型煤托盘及水冷炉梁的可靠性、低负荷运行时受热面的积灰及腐蚀、劣质型煤对锅炉运行的影响等问题做了分析并提出了改进措施,并介绍了型煤强化燃烧及蓄热式蒸汽锅炉两项新技术.     

燃煤电站锅炉折焰角积灰的原因分析及对策研究

针对某燃煤电站锅炉运行中出现的折焰角积灰现象进行了深入的原因分析和探讨,表明锅炉折焰角的结构会导致积灰、锅炉长时间不能满负荷运行和烟气流速的不均匀加重了折焰角的积灰、已有的声波吹灰装置能量偏低,对于折焰角的除灰效果不明显.根据锅炉实际运行情况,研究并提出了加装燃气脉冲激波吹灰器解决积灰的的方案.结果表明除灰效果显著,达到了预期的要求.     

四角燃烧煤粉锅炉稳燃技术的分析与应用

针对煤粉锅炉燃烧的稳定特性,从稳燃型煤粉燃烧器,煤粉浓度淡燃烧,二次风对一次风着火的影响以及炉内实际切圆等四个方面提出了稳定煤粉燃烧的措施,并介绍了这些措施在６７０ｔ／ｈ,４２０ｔ／ｈ和２２０ｔ／ｈ锅炉上应用的结果。     

25t/h煤粉锅炉改为燃甘蔗渣、煤混合燃料流化床锅炉的技术改造

文章介绍了25t/h煤粉锅炉改为燃甘蔗渣、煤混合燃料流化床锅炉的技术改造措施、运行情况及存在的问题。     

600MW亚临界锅炉褐煤燃烧系统设计与运行

本文通过对华能某电厂600MW亚临界燃煤机组风扇磨高水份褐煤燃烧系统的分析，结合燃烧调整和性能考核试验报告，介绍了燃煤发电机组的超临界风扇磨高水份褐煤燃烧系统设计，为今后的系统设计与运行提供了宝贵的经验。     

煤粉锅炉旋流燃烧器空气动力场的数值模拟

旋流煤粉燃烧器的气流组织情况对锅炉的稳定燃烧与安全运行都具有重要的影响,文中通过建立物理和数学模型,针对某电厂采用的中心给粉型旋流煤粉燃烧器进行了数值模拟研究,通过调整一次、二次风速和风量大小,得到不同运行工况下的速度流场和速度矢量分布,经分析各计算结果,得出各参量对流场的影响规律。     

Thermovoltaic effect of <Emphasis Type="Italic">p</Emphasis>Si-<Emphasis Type="Italic">n</Emphasis>(Si<Subscript>2</Subscript>)<Subscript>1−x</Subscript>(ZnS)<Subscript>x</Subscript> structures

The pSi-n(Si₂)_1−x (ZnS) _x (0 ≤ x ≤ 0.92) structure, on which thermovoltaic effect is observed, has been obtained by means of liquid-phase epitaxy from tin solution-melt on plates of p-type technical silicon. This effect is explained by grain boundary defects and influence of ZnS impurities in a thin layer adjacent to the p-n-junction.     

燃用神华煤的600 MW锅炉吹灰系统改进

分析燃用易结渣神华煤的600MW锅炉因过热器区域结渣、积灰造成主汽温偏低和空气预热器出口排烟温度偏高的原因,提出吹灰系统的改进方案.     

660MW机组四角切圆锅炉减少烟温偏差试验研究

针对某电厂660MW四角切圆燃煤锅炉左右两侧烟温偏差过大以及烟温偏差引起的过热器两侧吸热量偏差较大的问题,在实炉上进行了现场试验,研究单层分离燃尽风(SOFA)两侧角风门开度偏置和多层SOFA两侧角风门开度偏置对过热器两侧吸热量偏差和炉膛出口两侧烟温偏差的影响。结果表明:单独调整E层、D层和C层单层的SOFA两侧角风门开度偏置时,过热器两侧吸热量偏差变化很小,各层炉膛出口两侧烟温偏差的变化规律不一致;同时调整上三层SOFA两侧角风门开度偏置时,过热器两侧吸热量朝着A侧增大、B侧减小的方向变化,炉膛出口两侧烟温偏差随着SOFA两侧角风门开度偏置的增大而增大。     

燃用宽筛分煤循环流化床锅炉燃烧模拟计算

建立了循环流化床锅炉炉膛颗粒燃烧和脱硫反应模型。该模型考虑了炉膛下部为高颗粒浓度的密相区和上部为低颗粒浓度稀相区的特征,模拟计算给出了烟气温度,热流密度和各气体成分（Ｏ２,Ｃ２Ｏ,ＣＯ,Ｈ２Ｏ和Ｓ２Ｏ）的轴向分布,模拟计算结果的趋势是合理的。     

旋流煤粉燃烧器的气流组织与数值模拟

旋流煤粉燃烧器的气流组织情况对锅炉的稳定燃烧与安全运行都具有重要的影响,以CFD数值软件作为计算平台,通过建立物理和数学模型,针对某电厂采用的中心给粉型旋流煤粉燃烧器进行了数值模拟研究,通过调整一次、二次风速大小,得到不同运行工况下的速度流场和速度矢量分布,经分析各计算结果,得出各参量对流场的影响规律.     

热电站煤粉锅炉等离子点火器阳极冷却水系统优化

通过对等离子点火器阳极冷却水通道内的流场进行数值模拟,得到了不同冷却水进出方式、不同冷却水的流量及不同冷却通道长度时阳极表面的温度场,通过比较阳极冷却表面温度得出结论:随着进口冷却水流流量的增加冷却效果越好;随着冷却通道的长度增加冷却效果越来越好;上进侧出冷却水进出方式为最优方式。     

300MW煤粉锅炉燃烧产物中汞的分布特征研究

在对某300MW燃煤电站锅炉的煤，渣，底灰，飞灰进行取样后，通过煤样，灰样，渣样中的汞进行定量测量，并借助于质量平衡分析方法计算烟气中汞的浓度，获得了煤在大型电站锅炉中燃烧时汞污染物的分布特征及其排放特性，图5表1参9。