【作者】 李刚；

【导师】 丘纪华；

【作者基本信息】 华中科技大学 ， 热能工程， 2011， 硕士

【摘要】 近年来,温室效应加剧等问题使环境与经济可持续发展面临严峻的挑战。因此,对引起温室效应和全球气候变化的CO₂的减排技术研究成为各国关注的焦点。富氧燃烧技术可提高尾部烟气中的CO₂质量浓度,最高可达到95%以上,可显著降低CO₂的捕集能耗,但大型的富氧燃烧技术仍处于研究阶段,直供氧式O₂/CO₂旋流燃烧器的设计与试验研究正是在全球致力于CO₂减排的背景下进行的。本文从旋流燃烧器的工作原理以及影响燃烧器运行的各种因素出发,根据给定煤种设计出直供氧式O₂/CO₂旋流燃烧器（DOS）。结构设计包括燃烧器送气方式设计、气流流通面积设计、侧管连接主管方式设计、叶片与扩口设计。针对设计的DOS燃烧器做了空气动力场试验以及浓度场试验。空气动力场试验测量气流轴向速度,浓度场试验测量试验气体浓度。试验结果表明,旋流强度的大小、扩口变化对燃烧器回流区大小、扩展角大小以及气流的混合程度有很大影响。内二次风旋流强度增大,回流区尺寸增大,外二次风旋流强度增大,回流区宽度增大而长度减小,加装扩口后燃烧器旋流强度增大,并随着扩口角度增加,扩展角增大。气流混合情况包括外侧混合和内侧混合。外侧混合初期较强烈,并随着外二次风扩口的加大混合加强。内侧混合随着中心回流量的增大混合加强。进一步对DOS燃烧器进行了三种不同工况的热态试验,包括空气气氛、O₂/循环烟气气氛（内二次风为纯氧）及O₂/循环烟气气氛（内二次风为纯氧+循环烟气）。通过对炉膛各段温度以及炉膛截面温度的测量,对尾部烟气成分的测量,得出O₂/循环烟气气氛（内二次风为纯氧）下温度水平较其他工况高,尾部烟气中CO₂浓度也较高。总体而言,从试验结果可以看出直供氧式O₂/CO₂旋流燃烧器的设计是比较合理的,燃烧性能也比较优良,能够保证氧化剂较好的扩散至煤粉中,以保证燃烧需要。更多还原

【Abstract】 In recent years, the aggravation of Greenhouse effect problem leads to serious challenge to sustainable development of environment and economic. So, many countries focus on the emission reduction technology of CO₂ which mainly cause greenhouse effect and global climate changes. Oxy-fuel combustion technology can increase the CO₂ quality concentration to 95% in flus gas, which significantly reduce the energy consumption of CO₂ capture, but the large-scale oxy-fuel technology is still in the research stage, The design and experimental research of oxygen-direct-supply swirl burner is set in emission reduction of CO₂ around the world .This paper mainly studys about two different structure design of directly-oxygen- supply O₂/CO₂ swirl burner（DOS）according to their working principle and operation influenced factors of swirl burner. Structure design includes the way of the feeding gas supply, the feeding gas flow area, the way of side pipe connection with the main pipe, the blade and the expanding tuyere design. Aerodynamic field experiment and concentration field experiment are done to DOS .Aerodynamic field experiment measured axial velocity. Mixing experiment measured the concentration of test gas .The results show that swirling intensity and the change of the expanding tuyere influence recirculation zone and extended angle and mixablity of airflow on the burner. As the inner secondary air swirling intensity increases, the recirculation zone size increases; But as the outer secondary air swirling intensity increases, the width of recirculation zone increases and the length decreases. The swirling intensity increases after the installation of the expanding tuyere. And as the expanding tuyere angle increases, extended angle increases.The mixing condition included inside mixing and outside mixing.The outside mixing is intense in initial stage, and it enhanced as the expanding tuyere of the outer secondary air increased. The inside mixing enhanced as the quantity of recirculation increased. There are three different thermal tests to design DOS siwrl burner, including air atmosphere, O₂/RFG atmosphere（inside secondary air is pure oxygen）and O₂/RFG atmosphere （inside secondary air is pure oxgen and recirculating flue gas）.The experiment measured every segment’s temperature of the vertical combustor , the temperature of the furnace cross-section and composition of flue gas. The results show that the higher temperature level and the higher concentration of CO₂ can be obtained under the O₂/RFG atmosphere（inside secondary air is pure oxygen）.In a word, it shows that design of oxygen-direct-supply O₂/CO₂ swirl burner is reasonable, the combustion characteristics is fine, and which can assure the oxidant spread into coal to combust efficiently.更多还原