半焦富氧预热燃烧特性研究  

Study on Characteristics of Semi-coke With Oxy-fuel Preheating Combustion

作　　者：刘玉华 刘敬樟[1,2] 吕清刚 朱建国[1,2] 张孝禹 张嘉航[1,2] LIU Yuhua;LIU Jingzhang;LYU Qinggang;ZHU Jianguo;ZHANG Xiaoyu;ZHANG Jiahang(Institute of Engineering Thermophysics,Chinese Academy of Sciences,Haidian District,Beijing 100190,China;University of Chinese Academy of Sciences,Shijingshan District,Beijing 100049,China;School of Engineering Science,University of Science and Technology of China,Hefei 230026,Anhui Province,China)

机构地区：[1]中国科学院工程热物理研究所,北京市海淀区100190 [2]中国科学院大学,北京市石景山区100049 [3]中国科学技术大学工程科学学院,安徽省合肥市230026

出　　处：《中国电机工程学报》2023年第5期1875-1883,共9页Proceedings of the CSEE

基　　金：国家自然科学基金(面上基金项目)(51876204)。

摘　　要：为考察半焦在基于循环流化床的预热燃烧技术中的流态化预热特性、燃烧特性及污染物原始排放特性,在基于30kW循环流化床预热的富氧燃烧试验台上,采用空气、21%O_(2)/CO_(2)、23.9%O_(2)/CO_(2)和27.1%O_(2)/CO_(2)不同预热气氛对半焦进行预热燃烧试验,探究不同预热单元气氛对半焦改性程度及其富氧预热燃烧氮氧化物的排放特性。结果表明:预热过程可使半焦的比表面积增大为原来的30倍;同温度富氧气氛预热后燃料比表面积约为空气气氛的1.3倍,且产生的预热煤气热值为空气气氛下预热煤气热值的2.25倍;预热过程对其石墨化程度及反应活性位点比例影响较小。高燃烧区氧浓度下,尾部氮氧化物排放随预热单元氧浓度的增大而增大。富氧预热燃烧技术对于超低挥发分高固定碳燃料的气相改性更有优势,高预热氧气浓度对半焦改性有利,但不利于氮氧化物的控制。The purpose of this study is to investigate the fluidized preheating characteristics,combustion characteristics and pollutant emission characteristics of semi-coke in preheating combustion technology based on a circulating fluidized bed(CFB).Combustion experiments of Yulin semi-coke fired at the 30kW oxy-fuel combustion experimental facility with solid-fuel preheated by CFB under different preheating oxygen concentration atmospheres including air,21%O_(2)/CO_(2),23.9%O_(2)/CO_(2),and 27.1%O_(2)/CO_(2),are performed.The modified ratio of semi-coke under different preheating atmospheres,and its NO_(x) emissions regulation under the O_(2)/CO_(2) atmosphere are analyzed.The results show that the preheating process could increase the Brunner-Emmet-Teller(BET)surface area of semi-coke to 30 times that of the original BET surface area.The BET surface area of the fuel after preheating modification in an O_(2)/CO_(2) atmosphere at the same temperature is approximately 1.3 times that of the air atmosphere.The calorific value of preheated coal gas produced in an O_(2)/CO_(2) atmosphere is 2.25 times that of preheated coal gas produced in an air atmosphere.The preheating process has little effect on the graphitization degree and reaction active site ratio of semi-coke.Under the high oxygen concentration in the combustion zone,the NO_(x) emissions increase with increasing oxygen concentration of preheating unit.Oxy-fuel preheating combustion technology is more advantageous for the gas-phase modification of ultralow volatile carbon fuels.A high preheated oxygen concentration is beneficial to semi-coke modification,but not conductive to NO_(x) control.

关 键 词：预热燃烧技术 O_(2)/CO_(2)燃烧 半焦 循环流化床 NO_(x) 

分 类 号：TQ534[化学工程—煤化学工程]