压力对热解煤焦结构及其燃烧反应性的影响  

Effect of pressure on structure and combustion reactivity of pyrolysis coal char

作　　者：闫华青 张先炼 许凯 李寒剑 徐俊 汪一 江龙 苏胜[1] 胡松 向军[1] YAN Huaqing;ZHANG Xianlian;XU Kai;LI Hanjian;XU Jun;WANG Yi;JIANG Long;SU Sheng;HU Song;XIANG Jun(School of Energy and Power Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;Hubei Xisaishan Power Generation Co.,Ltd.,Huangshi 435000,China)

机构地区：[1]华中科技大学能源与动力工程学院,湖北武汉430074 [2]湖北西塞山发电有限公司,湖北黄石435000

出　　处：《洁净煤技术》2021年第4期68-76,共9页Clean Coal Technology

基　　金：国家自然科学基金资助项目(51806074)。

摘　　要：加压富氧燃烧被认为是一种更加高效清洁的第2代富氧燃烧技术而备受关注。热解作为煤燃烧的第1步,不同的热解条件(压力、气氛、升温速率等)将直接影响煤焦的物理和化学结构,导致其燃烧反应性的差异,目前加压富氧燃烧条件下,煤焦反应性与结构性质之间的关联研究鲜见报道。自主设计并建立了一套加压聚光光热快速升温试验平台,最大升温速率可达80℃/s,选用红沙泉(HSQ)和五彩湾(WCW)2种准东煤,制备了不同压力(常压~1.5 MPa)及热解气氛(N_(2)、CO_(2))下的煤焦,采用比表面积分析仪、拉曼分析仪、热重分析仪等表征手段考察了压力及热解气氛对煤焦的结构特性及其燃烧反应性的影响。结果表明,在惰性N_(2)气氛下,HSQ和WCW煤在压力1.5 MPa时的煤焦产率较常压下分别增加了3.54%和10.49%;在CO_(2)气氛下,HSQ煤在压力1.5 MPa时的煤焦产率较常压下降低了16.40%,煤焦产率在2种气氛下随压力的改变呈相反趋势。N_(2)气氛下,随着压力从常压增至0.4 MPa,HSQ/WCW煤焦的比表面积增加,从24.20/14.85 m^(2)/g增至26.27/46.19 m^(2)/g,但压力继续增至1.5 MPa时,HSQ/WCW煤焦的比表面积呈下降趋势,从26.27/46.19 m^(2)/g降至21.21/39.46 m^(2)/g;相同压力下,CO_(2)气氛下制备的煤焦孔隙结构更发达,常压和1.5 MPa压力时,CO_(2)气氛下制备的HSQ煤焦比表面积分别为N_(2)气氛制备煤焦的6.46和9.03倍,这也是CO_(2)气氛下制备的HSQ煤焦燃烧反应性优于N_(2)气氛煤焦的主要原因。随着压力增加,2种气氛下,2种煤焦拉曼光谱分峰拟合计算得到的I(GR+VL+VR)/I D值均逐渐下降,煤焦的化学结构趋于更加稳定,这也使得高压下制备煤焦的燃烧反应性下降。但相同压力下,CO_(2)气氛下制备的HSQ煤焦I_((GR+VL+VR))/I_(D)值低于N_(2)气氛制备的HSQ煤焦,高压下由于CO_(2)与焦炭的气化反应增强,消耗更多的无定形碳,2种气氛的I_((GR+VL+VR))/I_(D)差异更明显,�Pressurized oxy-fuel combustion has attracted much attention,which is considered to be a more efficient and cleaner second-generation oxy-fuel combustion technology.As the first step of coal combustion,different pyrolysis conditions(pressure,atmosphere,heating rate,etc.)directly affect the physical and chemical structure of char,which in turn leads to different combustion reactivity.At present,under the conditions of pressurized oxy-fuel combustion,there is few report on the correlation between the reactivity and structural properties of char.A pressurized concentrating photothermal apparatus whose maximum heating rate could reach 80℃/s was independently designed and established.Two kinds of Zhundong coals,Hongshaquan(HSQ)and Wucaiwan(WCW)were selected to prepare char under different pressures(atmospheric pressure-1.5 MPa)and pyrolysis atmospheres(N_(2),CO_(2)).The specific surface area analyzer,Raman analyzer,thermogravimetric analyzer were used to systematically investigate the influence of pressure and pyrolysis atmosphere on the structural characteristics of char and its combustion reactivity.The results show that under inert N_(2) atmosphere,the char yield of HSQ and WCW coal at 1.5 MPa increase by 3.54% and 10.49%,respectively,compared with atmospheric pressure.While under CO_(2) atmosphere,compared with atmospheric pressure,the char yield of HSQ coal at 1.5 MPa decreases by 16.40%,and the char yield shows opposite trends with pressure changes under two kinds of atmospheres.Under N_(2) atmosphere,the specific surface area of HSQ/WCW char increases from 24.20/14.85 m^(2)/g to 26.27/46.19 m^(2)/g with the pressure increases from atmospheric pressure to 0.4 MPa.However,when the pressure continues to increase to 1.5 MPa,the specific surface area of HSQ/WCW char decreases from 26.27/46.19 m^(2)/g to 21.21/39.46 m^(2)/g.Under the same pressure,the pore structure of char prepared under CO_(2) atmosphere is more developed.At atmospheric pressure and 1.5 MPa,the specific surface area of HSQ char prepared under CO_

关 键 词：富氧燃烧 热解 压力 煤焦 CO_(2) 比表面积 化学结构 燃烧反应性 

分 类 号：TQ53[化学工程—煤化学工程] TK114[动力工程及工程热物理—热能工程]