环形文丘里喷射器组甲烷非预混燃烧数值模拟研究  

Numerical Simulation of Methane Non-premixed Combustion of Annular Venturi Injector Group

作　　者：曹文宣 徐杰 王子兵 秦培禾 CAO Wenxuan;XU Jie;WANG Zibing;QIN Peihe(School of Metallurgy and Energy,North China University of Technology,Tangshan 063000,Hebei Province,China)

机构地区：[1]华北理工大学冶金与能源学院,河北省唐山市063000

出　　处：《中国电机工程学报》2023年第19期7539-7548,共10页Proceedings of the CSEE

摘　　要：以某厂0.8MW锅炉炉膛实际结构及传热条件为基础,重点研究环形文丘里喷射器组结构下甲烷非预混燃烧过程中射流特性与烟气炉内循环特性之间的关联规律,采用数值模拟的方法探究燃料分级配比和烟气内循环强度对炉内流场、温度分布以及氮氧化物生成特性的影响规律。结果表明:燃料分级配比存在最佳值,过度向炉内转移燃料热负荷不仅会破坏燃烧稳定性,而且会增强局部高温导致氮氧化物浓度的升高;在不受其他因素干扰的情况下,喷射器卷吸烟气量越大,降氮效果就越好,此时仅采用烟气循环率?这一指标难以对实际情况进行合理的描述;采用大比例精细煤气分级与高强度烟气内循环协同技术,可以实现10mg/Nm3以下的低NOx燃烧效果,将最佳工况与未采用文丘里管引射燃烧技术的模拟结果进行对比,出口氮氧化物浓度降低97.5%。Based on the actual structure and heat transfer conditions of a 0.8MW boiler in a factory,the correlation law between the jet characteristics and the circulation characteristics of the flue gas furnace in the non-premixed combustion process of methane under the structure of the annular Venturi injector group is mainly studied.The simulation method explores the influence of fuel grading ratio and flue gas internal circulation intensity on the flow field,temperature distribution and nitrogen oxide generation characteristics in the furnace.Results show that there is an optimal value for the fuel grading ratio;excessive transfer of fuel heat load to the furnace will not only destroy the combustion stability,but also enhance the local high temperature and lead to an increase in the concentration of nitrogen oxides;without the interference of other factors,the larger the volume of smoke in the ejector,the better the effect of nitrogen reduction,and then it is difficult to describe the actual situation reasonably only by using the flue gas circulation rateѡindex.Using the synergistic technology of large-scale fine gas classification and high-intensity flue gas internal circulation,a low NO_(x)combustion effect of less than 10mg/Nm^(3) can be achieved.The nitrogen oxide concentration at the outlet is reduced by 97.5%.

关 键 词：天然气 低NOX 烟气内循环 文丘里管喷射器 引射燃烧 

分 类 号：TK16[动力工程及工程热物理—热能工程]