摘要我国能源主要结构是以燃煤为主,煤炭燃烧过程产生大量粉尘污染环境,排放的氮 氧化物和二氧化硫等气体污染大气。生物质是一种清洁能源,合理利用生物质经济有效 的方法之一就是生物质与煤混燃,这种燃烧技术是一种洁净燃烧技术,可以减轻环境污 染,改善大气质量,在生物质能利用领域引起了极大的关注。因此,本论文以此为背景, 对生物质与煤单独燃烧和混燃进行基础研究,分析生物质燃烧特性和生物质混煤燃烧的 燃烧特性,为大型冶金企业燃煤技术方面提供理论依据。84589
首先,本文采用梅特勒托利多同步热分析仪进行热重分析,研究了三种不同粒径的 锯木屑和相同粒径的竹屑、稻壳、神华烟煤和阳泉无烟煤在三种不同升温速率下单烧的 燃烧特性,探讨了粒径大小和升温速率对样品燃烧特性的影响。结果表明,燃料燃烧与 自身特性有关,生物质燃烧主要在燃烧前期,而煤粉主要在后期固定碳燃烧阶段,并且 燃料粒径越小,生物质的燃烧性能越好,因此粒径选择在 200 目以上;升温速率越快, 曲线 TG 和 DTG 曲线右移,不利于燃烧,但又由于升温速率越低最大燃烧速率也越低, 所以升温速率选择为 25℃/min。结果还表明三种生物质中竹屑的燃烧性能最好,其次为 锯木屑,稻壳的燃烧性能较差。
其次,在确定粒径和升温速率后,采用这五种实验原料以三种不同掺混比例进行混 合燃烧实验研究。实验结果表明,生物质的加入大大改善煤粉的综合燃烧性能,生物质 的燃烧特性明显优于煤粉,混煤燃烧时的着火温度和生物质着火温度接近。随着掺混比 例的增大,混煤燃烧时的着火温度和燃尽温度逐渐降低。烟煤和无烟煤单独燃烧时的综 合燃烧特性指数分别为 5。70×10-7 和 2。50×10-7,随着生物质与煤粉掺混比例增大,综合 燃烧特性指数呈线性上升,在生物质与煤粉掺混比 1:1 时,生物质对煤粉促进作用越明 显。不同种类生物质与煤混燃均可以改善煤的燃烧特性,但是不同生物质对煤的改善程 度不一致。在相同升温速率下,当掺混比例为 1:1 时,两种煤粉掺混生物质混燃的综合 燃烧特性指数的最大值分别是:竹屑与烟煤混燃的燃烧综合特性指数为 7。93×10-6,锯木 屑与无烟煤混燃的综合燃烧特性为 4。25×10-5。因此煤粉由各自对应的最佳掺混生物质。 神华烟煤对应的是竹屑,而阳泉无烟煤对应的是锯木屑。
毕业论文关键词:生物质;混燃;热重分析;综合燃烧性能
Abstract In China's major coal-based energy structure, coal combustion process generates a lot of dust pollution, nitrogen oxides and sulfur dioxide and other gas emissions atmospheric pollution。 Biomass is a clean and renewable resource that can be stored, and China is rich in biomass resources, rational utilization of cost-effective method is to biomass co-combustion of biomass with coal, the combustion technique is a clean combustion technology, reduce environmental pollution and improve air quality in the field of biomass utilization caused a great deal of attention。 Thus, the present paper this background, and biomass combustion and co-combustion of coal alone basic research, analyzing the combustion characteristics of coal and biomass co-combustion of biomass combustion characteristics, provide a theoretical basis for the technical aspects of large-scale coal-fired metallurgical enterprises。
Firstly, METTLER TOLEDO simultaneous thermal analyzer TGA studied bamboo shavings and sawdust of the same diameter in three different particle size, rice hulls, Shenhua bituminous coal and anthracite in Yangquan three different heating rates combustion characteristics of a single burning study the effects of particle size and heating rate of the sample combustion characteristics。 The results showed that, with its own characteristics of the fuel combustion, biomass burning, mainly in the pre-combustion, and pulverized coal mainly in the latter part of the fixed carbon combustion stage, and the smaller the particle size of the fuel, the better the performance of biomass combustion, so choose a particle size of 200 mesh; heating rate faster curve TG and DTG curve to the right, is not conducive to burning, but due to the lower heating rate maximum burning rate is also lower, so the choice of heating rate 生物质混煤燃烧特性的研究:http://www.youerw.com/cailiao/lunwen_100512.html