【作者】 文午琪；

【导师】 黄素逸； 靳世平；

【作者基本信息】 华中科技大学 ， 工程热物理， 2013， 博士

【摘要】 低热值气体燃料是指热值小于1460kcal/Nm~3的气体燃料，广泛存在于煤炭生产、煤化工、石油化工、钢铁、冶金、纺织印染等行业的生产过程中，如高炉煤气、转炉煤气、炭黑尾气等。以上几类气体的热值均在600kcal/Nm~3以上，工业应用比较广泛。而更低热值水平的超低热值气体燃料工业应用研究机近年来才受到重视，这类气体热值更低，但来源更加广泛，总量也更巨大，强化其循环利用具有重要的节能和环保意义，也有利于提高能源利用率，进而缓解我国能源供需矛盾。基于此背景，本文选取了研究对象——300kcal/kg的超低热值气体燃料。并针对低热值气体燃料特点，提出了两种超低热值气体燃料的强化燃烧方法——高低热值气体燃料混合燃烧、燃煤与低热值气体燃料混合燃烧，并开展了实验和工业化应用研究。主要研究情况如下：（1）在高低热值气体燃料混合燃烧环节，基于回流区分级着火原理，本文通过旋流燃烧器的结构优化和调整燃料配比等措施研究了燃烧器的低热值气体稳燃性能，研究结果表明：当二次空气和主燃料喷口旋流角度均为60°时，燃烧器可实现300kcal/kg低热值主燃料的稳定燃烧，此时高低热值燃料供热比21:79，平均热值379kcal/kg。而采用乙炔掺烧时可以将主辅燃料平均热值进一步降低到300kcal/kg，原因在于乙炔等小分子燃料具有更好的着火和稳燃性能。同时，本文将实验成果应用到褐煤提质工艺的热解气热风炉中也取得了较好的燃烧效果，高低热值热量比达到了23.5:76.5，从而证明了基于回流区分级着火原理设计的气体燃烧器在低热值气体燃料稳燃方面具有独特优势。（2）在燃煤与低热值气体燃料混合燃烧环节，本文通过分体式燃烧和一体式燃烧实验对比发现：一体式燃烧装置性能更优，可实现273kcla/kg的低热值气体燃料稳定燃烧，其稳定燃烧条件是保证炉膛温度在850℃以上。同时，根据实验现象发现加煤速度与燃煤烟气温度、助燃的燃煤烟气温度与低热值气体可燃热值之间均存在边际递减效应，也根据实验现象总结出了吸热射流扩散燃烧和平衡极限热值等概念。在燃煤与低热值气体燃料混合燃烧实验基础上，本文还进行了褐煤提质工艺中燃煤替代LNG作为补充燃料的工业化应用研究，研究结果表明燃煤替代LNG方案技术上是可行的，经济效益也比较显著。投产后一年运行成本可节约1362.17万元，5个月内即可收回486.28万元的改造工程款。它的建成投产将大幅度降低系统运行成本，提升褐煤提质技术含量，从而有利于在褐煤提质技术大规模推广应用。更多还原

【Abstract】 The low calorific value gas fuels whose calorific value is under1464kcal/Nm~3arewidely used in process of coal production, coal chemical industry, petrochemicalengineering, steel industry, metallurgical industry and textile industry. For instance,blast-furnace gas, converter gas and carbon black off-gas can be categorized as lowcalorific value gas. The calorific values of the gas that mentioned above are above600kcal/Nm~3, which can be utilized in industrial areas extensively and efficiently.However, the industrial applied research of super-low calorific value gas has come topublic attention in last several years. What is worth mentioning is that this kind of gas fuelcan be obtained easier in productive process than so called low calorific value gas. Andfor its large quantity in industrial areas, to develop the methods for its cyclic utilization isbeneficial to both energy conservation and environmental protection.As stated above, the super-low calorific value gas whose calorific value is300kcal/kgis chosen as the research subject under this study. According to the characteristics of thefuel evolved in this study, there propose two enhanced burning methods using lowcalorific value gas as working fuel. The first method is combined firing of both high andlow calorific value gas, while the second one is combined firing of coal and low calorificvalue gas. The research is conducted both experimentally and theoretically and the resultscan be used for future academic and industrial references. More details are as follow:1) Combined firing of both high and low calorific value gas fuelIn this study, we experimentally investigate the stabilized combustion performance ofthe turbulent burner whose structure has been optimized with different ratios of mixed gasfuel--high and low calorific value gas. The analytical data show that when the swirl anglesof both secondary air flow and main fuel are60o, the stable combustion condition can beachieved using low calorific value gas with the calorific value300kcal/kg as main fuel. Inthis case, the ratio of high and low calorific value gas is21:79with the mean calorificvalue379kcal/kg. However, the mean calorific value of main fuel can be depressed to300kcal/kg if acetylene is added to main fuel as supplement, due to the moderate ignitability and stabilized combustion performance of acetylene.Furthermore, this combined firing method has proven to be efficient when it is appliedto pyrolysis gas furnace which is used in lignite upgrading process. In this case, the ratioof high and low calorific value gas is23.5:76.5. As a result, we can draw the conclusionthat the gas burner which is designed based on grading fire principle of recirculationzone has its own superiorities in ignitability and stabilized combustion performance.2) Combined firing of coal and low calorific value gasCompared with the separated device, the performance of integrated device is morepredominant. The low calorific value gas can obtain stable combustion condition whenthe temperature of hearth can be guaranteed to exceed850℃, even if the calorific valueof gas fuel is just273kcla/kg. Meanwhile, according to the experiment, the decreasededge effect is existed in the relationship between the feeding speed of coal and thetemperature of fuel-gas. The similar conclusion can be seen in the relationshipbetween temperature of fuel-gas emitted from combustion-supporting coal and thecalorific value of low calorific value gas.Based on the previous study, we also find that coal can substitute for LNG as the postcombustion, which is more reliable and economical in running lignite upgrading process.In detail, the running cost of lignite upgrading process can be cut down for13.6217million Yuan per year after reforming and the reform cost can be recovered in five months.In other word, The running cost would be dramatically decreased and the technology oflignite upgrading process would be improved if the reforming scheme is up and running.更多还原