【作者】 吕峰；

【导师】 杨天华；

【作者基本信息】 沈阳航空航天大学 ， 安全技术及工程， 2012， 硕士

【摘要】 生物质是一种清洁的可再生能源,将其与煤混燃可实现生物质的大规模、高效利用,但由于生物质中富含大量碱金属,易导致燃料在混燃过程中产生固相沉积和腐蚀等问题。本文采用理论与实践相结合的方法,通过SEM、XRD和EPMA等先进测试手段对生物质与煤混燃过程中固相沉积特性进行了深入的研究。通过分析生物质与煤混燃成灰的灰成分,灰中各物质含量均随着生物质含量的增加呈非线性变化。随着生物质的含量的增加,碱金属K、Na,碱土金属Mg、Ca含量增加,K由最低的2%增至最高的18%,而Na由1%增至6%,这与生物质中碱金属和碱土金属含量高有关;Si的含量在灰成分中稳定在50%~60%之间,生物质的混合比例,反应温度,反应时间对Si的含量的没有较大的影响。Al也是灰中另一个重要的元素,其含量仅次于Si的含量,并且Al含量是随着生物质含量的增高而降低,Al含量由最大的20%降至8%。利用XRD分析得出,生物质与煤混燃过程中,碱金属及碱土金属对积灰结渣的贡献较大,其中以钾长石、钠长石、硫酸钠和钙长石为主,而且前三种物质本身就具有较强的粘性,这几种物质都有较低的熔点,能够使沉积物在较低的温度就呈现熔融状态。通过EPMA的分析发现,Si,Al和Ca是沉积物的主要元素,不同的混合比例或者不同反应时间的条件下,对其在沉积物中的含量影响不大。Si和Al有着相似的分布,可见在沉积过程中铝硅酸盐和Fe元素都起了重要的作用。钾长石在沉积物的内部同样存在,使沉积物的结构更加稳定。稳定的Ca的化合物大部分在沉积物的内部。在沉积物表面形成的钾长石和硫酸钠的粘性使沉积物更容易富集。更多还原

【Abstract】 Biomass is a kind of clean and renewable energy source, with the coal mixed combustion can realize large-scale and high-efficiency use of biological mass, but because biomass is rich in alkali metal, it is easily lead to produce solid phase deposition and corrosion problems during the mixed fuel combustion process. A method of theory combining with practice is adopted in this paper, For getting in-depth study about solid phase depositionary characteristics during the process of biomass and coal mixed combustion, advanced test method is used, such as SEM、XRD and EPMA.Through the analysis of ash contents in the dust generated during coal combustion with biomass, the results show that every material content in the dusts are increase with the increased content of biomass presenting as nonlinear changes. Along with the increase of biological mass content, alkali metal of K, Na and alkaline metal Mg, Ca content increase, K in 2%~18%, and Na in 1%~6%, it is In relation to high content of alkali metal and alkaline metal in the biomass;the content of Si in the ash is more stable, it is in 50%~60%, the biomass mixture ratio, reaction temperature and reaction time don’t have a major influence to Si content. Al is another important element in the ashes, Its content is only second to Si content, Al become 20%~8% and it’s content is decreased as biomass content adding.XRD analysis reached some conclusions that alkali metal and alkaline metal have a significant contribution to fouling and slagging during the process of biomass and coal mixed combustion, potassium feldspar, albite, sodium sulfate and calcium feldspar have a primarily position, and the first three kind of materials itself have strong viscosity and lower melting point, these features make deposition appearing molten state in the lower temperature.EPMA analysis discovered Si, Al and Ca is the key elements of depositions, in the situation of different mixture proportion or different reaction time, the effect on the main elements content in the deposition would be modest. Si and Al have similar distribution, it is visible that aluminosilicate and Fe elements play an important role during the process of deposition. Potassium feldspar exist in the interior of the deposition, it make the structure of the deposition more stable. Most of stable Ca compounds is in the interior of the depositions. The viscosity of Potassium feldspar and sodium sulfate formed in the depositions surface make depositions to concentrate more easily.更多还原