平焰燃烧器煤/NH_(3)燃烧特性实验研究  

Experimental study on combustion characteristics of coal/NH_(3) in a flat flame burner

作　　者：崔名双 牛芳 纪任山 王乃继 张鑫 梁兴 底一 王圣烨 CUI Mingshuang;NIU Fang;JI Renshan;WANG Naiji;ZHANG Xin;LIANG Xing;DI Yi;WANG Shengye(Beijing Tiandi Rongchuang Technology Co.,Ltd.,Beijing100013,China;National Energy Technology&Equipment Laboratory of Coal Utilization and Emission Control,Beijing 100013,China;Shaanxi Qinghua Vehicle Safety Systems Co.,Ltd.,Xi’an 710025,China)

机构地区：[1]北京天地融创科技股份有限公司,北京100011 [2]国家能源煤炭高效利用与节能减排技术装备重点实验室,北京100013 [3]陕西庆华汽车安全系统有限公司,陕西西安710025

出　　处：《煤炭学报》2024年第8期3667-3676,共10页Journal of China Coal Society

基　　金：天地科技股份有限公司科技创新创业资金专项资助项目(2023-TD-ZD014-001);煤科院节能技术有限公司科技发展基金资助项目(2022JNCX-04)。

摘　　要：随着“碳达峰,碳中和”目标的提出,将煤与NH_(3)混燃逐步减少煤电是实现降碳的一种新途径,但煤/NH_(3)的混燃特性尚不清晰。因此,基于平焰燃烧器开展煤/NH_(3)燃烧实验,探究了掺氨比(E(NH_(3)),0~100%)、煤/NH_(3)注入方式(预混、非预混)对燃烧特性的影响,采用相机、烟气分析仪,热电偶检测了火焰形态、燃烧器上方高度(Heights Above Burner,HAB)中心沿程烟气中气体组分及温度分布情况,并测定了飞灰中未燃碳的含量,得到:在燃烧初期,煤/NH_(3)争夺O_(2)的现象更明显,由于燃烧区NH_(3)燃烧产生的富水气氛,使得在预混低E(NH_(3))下,CO与OH发生反应,CO质量浓度降低,而在高E(NH_(3))下,一方面NH_(3)优先与O_(2)结合,导致大量碳不完全燃烧,另一方面,富水气氛促进了煤的气化反应,导致燃烧还原区的CO质量浓度大幅升高,最高可达19773.05 mg/Nm^(3),但此过程改变了焦炭的孔隙结构,增加了焦炭的比表面积,加快了煤粉的燃烧进程,使预混条件下飞灰残炭量由13.90%(纯煤燃烧)降低至13.44%(E(NH_(3))=80%),过早注入NH_(3)会减轻燃烧前期NH_(3)燃烧对煤粉的预热作用,降低在火焰反应区的燃烧强度;掺NH_(3)后NO_(x)排放量大幅上升,随着E(NH_(3))增加,NO_(x)先增加后降低,且NO质量浓度峰值提前,未燃NH_(3)及氧体积分数分别是影响N_(2)O、NO_(2)生成的主要因素,增加煤/NH_(3)燃烧的停留时间、减少未燃NH_(3)体积分数、创造还原性气氛均是降低NO_(x)的有效方式;在预混高掺氨比(E(NH_(3))≥80%、HAB=100 mm)及非预混工况下,CO_(2)%随着E(NH_(3))增加呈现降低的趋势;预混E(NH_(3))=40%~60%工况更有利于实现煤/NH_(3)的低氮、低碳、高效燃烧,煤粉掺NH_(3)燃烧存在相互促进和抑制作用,需根据实际情况采取有效措施以发挥煤/NH_(3)混燃的促进作用。To meet the“peak carbon and carbon neutrality”targets,the gradual reduction of coal-fired electricity generation through the co-firing of coal and NH_(3) has emerged as a new pathway to achieve carbon reduction.However,the cofiring characteristics of coal and NH_(3) are not yet clear. Therefore, the coal/NH_(3) co-firing experiments were conducted based on a flat-flame burner to investigate the influence of ammonia blending ratio (E(NH_(3)), 0−100%) and coal/NH_(3) injec-tion methods (pre-mixed, non-pre-mixed) on combustion characteristics. Camera, flue gas analyzer, and thermocouples were used to observe flame morphology, gas composition, temperature distribution along the centerline heights above the burner (HAB), and measure the unburned carbon content in fly ash. The results showed that during the initial stage of com-bustion, the competition for O_(2) between coal and NH_(3) was more pronounced. The NH_(3) combustion in the combustion zone created a rich water vapor atmosphere. Under low E(NH_(3)) conditions in pre-mixed combustion, CO reacted with OH, res-ulting in a decrease in CO concentration. On the other hand, under high E(NH_(3)) conditions, NH_(3) preferentially reacted with O_(2), leading to an incomplete combustion of a significant amount of carbon. Additionally, the rich water vapor atmo-sphere promoted coal gasification reactions, resulting in a significant increase in CO concentration in the combustion re-duction zone, reaching a maximum of 19 773.05 mg/Nm^(3). However, this process altered the pore structure of the coke, in-creased the specific surface area of the coke, accelerated the combustion process of coal powder, and reduced the residual carbon content in fly ash from 13.90% (pure coal combustion) to 13.44% (E(NH_(3))=80%) under pre-mixed conditions. An early injection of NH_(3) reduced the preheating effect of NH_(3) combustion on coal powder and decreased the combustion in-tensity in the flame reaction zone. The addition of NH_(3) significantly increased the NO_(x) emissions, and

关 键 词：煤/NH_(3)混合燃料 燃烧特性 掺氨比 煤/NH_(3)注入方式 气体组分 

分 类 号：TQ530[化学工程—煤化学工程]