摘要
用Fluent软件对国内某高原水泥厂TTF分解炉进行掺杂褐煤混燃的数值模拟分析,研究分解炉褐煤-烟煤混燃增效机制。研究结果表明:在高原环境下加入30%~50%的褐煤能有效改善分解炉内燃料的燃烧状态,可降低混合燃料的着火点,增加分解炉内煤粉的燃尽率,同时有利于分解炉内形成均匀分布的温度场;同时在所研究的高原环境中当燃料各组分等比例混燃时增效效果最为显著,表现在这种比例下,混煤挥发分析出的程度最好,使分解炉的温度分布更加均匀,进而也使得窑系统内热力型NO_(x)排放量减少;此外与单独燃烧烟煤相比,温度场的改善也归功于混煤固定碳燃尽阶段的滞后。
The CFD simulations of the TTF precalciner in a high-alitude cement plant is studied in the paper,where the mixture of bituminous coal replaced by different amounts of lignite(0%,30%,50%,70%and 100%respectively)is used as fuel.By comparing various data in thermal calculation and numerical simulation,the differences in combustion and the kinetic characteristics of altemnative fuels and bituminous coal when Co-combusting,the mechanism of the high-ficiency co-combusting of atermative fuels in the limited space of the cement kiln was clarified,which could be conducive to improve the efficiency of alternative fuels of cement plants in China.The results show as the following:(1)Adding 30%~50%lignite can efectively improve the combustion in the calciner,decrease the mixed fuel to ignite,promote the bumout rate of mixed fuel and the formation of a uniformly distributed temperature field in the precalciner,which arises from their different combustion characteristics,So that the heat and mass transferring mechanism of these two fuels and their chemical reaction would be different,mainly manifesting in the low pressure promoting the evaporation of moisture,the precipitation of volatiles,and the ignition of fixed carbon in the lignite.(2)When the fuel components under the same radio,the synergistic effect of co-combustion is the best,mainly manifesting in promoting the precipitation of mixed coal's volatiles immensely,making the temperature distribution of the calciner more uniform and reducing the thermal nitrogen oxide produced.(3)In addition,compared with buming bituminous coal alone,the elongation of the high-temperature zone and the constant improvement of the temperature field are also attributed to the lag of the fixed carbon burmnout of the mixed coal.Local temperature increasing is due to lignite voltilcs contributing to the release and ignition of bituminous coal volatiles which establishes an oxygen-deficient environment,The bumout inhibition of the fixed carbon generates carbon monoxide,which is then burned in the upper part of the precalciner and contributes to the uniform temperature distribution in the precalciner.
作者
周尚群
赵青林
龙泉名
Zhou Shangqun;Zhao Qinglin;Long Quanming(School of Materials Science and Engineering,Wuhan University of Technology,Wuhan 430070,China)
出处
《新世纪水泥导报》
CAS
2022年第6期22-29,I0010,共9页
Cement guide for new epoch
基金
武汉理工大学材料科学与工程学院创新创业训练计划项目(项目编号:CY202036)。
关键词
褐煤
分解炉
混燃机制
数值模拟
CFD
lignite
calciner
co-combustion
numerical simulation
CFD
