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燃煤过程中产生的细微颗粒物,因严重威胁到人类的健康,其生成和控制受到越来越多的关注.混煤燃烧被认为是一种可有效减少电厂燃煤过程中细微颗粒物生成的控制手段.将具有不同矿物组成的褐煤和烟煤进行不同混合比例(9:1,7:3,5:5,3:7,1:9)和不同燃烧气氛下(O2/N2和O2/CO2)的沉降炉燃烧实验,通过对其燃烧生成的颗粒物进行质量粒径分布、生成浓度、元素组成和形貌成分等分析,研究了不同燃烧气氛下混煤燃烧对颗粒物生成特性的影响.煤粉燃烧生成的颗粒物由具有13级粒径分级功能的低压撞击器(LPI)进行收集.研究结果表明,两种实验煤粉混合燃烧后,PM1的生成相比于通过两种单一煤种加权平均得到的计算值有不同程度的减少,说明来自不同煤种的矿物之间的交互作用抑制了燃煤过程中PM1的生成.煤粉混合比例对PM1生成的抑制程度有重要影响,在本实验研究中,当褐煤与烟煤的混合质量比为7:3时,PM1的生成所受抑制程度最大.O2/CO2气氛对混煤燃烧过程细微颗粒物的生成特性有影响,相比于O2/N2燃烧气氛,O2/CO2燃烧气氛下,混煤燃烧后矿物交互作用减弱,PM1的生成所受抑制程度下降.与计算值相比,混煤燃烧后PM1中的Ca,Fe元素生成浓度和质量百分数均减少,而PM10+中Ca,Fe,Si,Al元素生成浓度增多,烟煤中所含的大量硅铝酸盐与褐煤燃烧过程中生成的含Ca,Fe等细颗粒物的交互作用是混煤后PM1生成减少的主要途径.
As a result of the serious threat to human health, the generation and control of fine particulates in coal combustion process are receiving more and more attention. Blended coal combustion is considered as a kind of control which can effectively reduce the generation of fine particulates in coal-fired power plants Means of different combinations of lignite and bituminous coal with different mineral composition (9: 1, 7: 3, 5: 5, 3: 7 and 1: 9) and different combustion atmospheres (O2 / N2 and O2 / CO2) The combustion experiment of the sedimentation furnace was carried out and the effects of the combustion of the mixed coal on the formation characteristics of the particulate matter were studied by analyzing the mass particle size distribution, the formation concentration, the element composition and the morphology of the particles produced by the combustion. The generated particles were collected by a low pressure impactor (LPI) with a 13-grade particle size classification.The results show that after two kinds of experimental pulverized coal combustion, PM1 generation compared with the weighted average by two kinds of single coal The calculated values have different degrees of reduction, indicating that the interaction between minerals from different coal types inhibits the formation of PM1 in the process of coal combustion.The proportion of pulverized coal mixture has an important impact on the degree of inhibition of PM1 generation. In this experimental study, When brown When the mass ratio of coal to bituminous coal is 7: 3, the formation of PM1 is inhibited to a great extent.The O2 / CO2 atmosphere has an influence on the formation of fine particulates during the combustion of mixed coal. Compared with O2 / N2 combustion atmosphere, O2 / Under the combustion atmosphere of CO 2, the interaction of minerals decreases and the inhibition degree of PM1 production decreases after the combustion of mixed coal.Compared with the calculated value, the formation concentration and mass percentage of Ca and Fe in PM1 decrease, while PM10 + The concentration of Ca, Fe, Si and Al in the coal increases, and the interaction between a large amount of aluminosilicate contained in bituminous coal and fine particles such as Ca and Fe formed during the combustion of lignite is the main way to reduce PM1 production after coal blending .