油页岩半焦燃烧过程中含氧官能团和孔隙结构的演变研究

发布时间：2018-06-27 15:26

本文选题：油页岩半焦 + 燃烧　；参考：《东北电力大学》2017年硕士论文

【摘要】：油页岩半焦是油页岩干馏炼油后的固体废弃物,具有一定的热值,主要以堆弃处理,但在堆弃的过程中会产生大量的污染物,将对环境造成巨大危害。燃烧油页岩半焦充分利用其剩余热量,是解决该问题的突破方向之一。本文从含氧官能团和孔隙结构着手,分析了油页岩半焦在燃烧过程中含氧官能团和孔隙结构的变化规律,进一步的了解了油页岩半焦在燃烧过程中表面微观结构变化。本文主要研究内容如下:首先在热重实验的基础上,对油页岩半焦的燃烧特性及TG-DTG曲线进行分析研究,结果表明:提高升温速率可以在一定程度上阻碍油页岩半焦的着火,推迟油页岩半焦的燃烧完全,有助于促进油页岩半焦的燃烧;从综合燃烧特性来看,三种半焦中YJSC的综合燃烧特性最好,LKSC次之,WQSC最差。通过管式炉对三种油页岩半焦进行燃烧试验,以获取不同燃烧终温不同的灰样,然后,用傅里叶变换红外光谱仪进行样品测量官能团的测定分析。结果表明:WQSC、LKSC、YJSC三种半焦的红外谱图结构相似,只是部分吸收峰的峰强度存在差异,且羟基区的振动吸收很弱,半焦中不存在明显的羧基振动吸收。随着燃烧的不断深入,羟基区的振动吸收峰渐渐消失,酚、醇、醚、酯的C-O键相对含量呈递增趋势,羰基含量呈波动变化。同时随着燃烧的进行,芳香骨架的振动吸收慢慢变弱,脂肪烃的C-H键也随氧化消耗而减少。最后在管式炉燃烧试验的基础上,利用氮等温吸附脱附法研究不同燃烧终温油页岩半焦的孔隙结构特性的变化情况,并通过分形维数来阐述半焦及其燃烧灰样的表面形态的复杂程度。分析结果表明油页岩半焦的孔隙结构多为缝形孔,且以中孔和微孔居多。在燃烧过程中,比表面积有减小、增加再减小的变化,颗粒中微孔及中孔对比表面积的变化起决定作用。采用FHH方程线性回归获得的分形维数表达出汪清油页岩半焦和龙口油页岩半焦中孔隙特征在燃烧过程中变化较为均匀。
[Abstract]:Oil shale semi-coke is a solid waste after oil shale dry-distillation refining, which has a certain calorific value and is mainly treated by heap disposal. However, a large number of pollutants will be produced in the process of dumping, which will cause great harm to the environment. The combustion of oil shale semi-coke is one of the breakthrough directions to solve this problem by making full use of its residual heat. In this paper, the changes of oxygen-containing functional groups and pore structures in the combustion process of oil shale semi-coke are analyzed, and the surface microstructure changes of oil shale semi-coke during combustion are further understood. The main contents of this paper are as follows: firstly, on the basis of thermogravimetric experiments, the combustion characteristics and TG-DTG curves of oil shale semi-coke are analyzed. The results show that increasing the heating rate can hinder the ignition of oil shale semi-coke to some extent. Delaying the combustion of oil shale semi-coke is helpful to promote the combustion of oil shale semi-coke, and the YJSC has the best comprehensive combustion characteristic in terms of its comprehensive combustion characteristics, followed by LKSC, and WQSC is the worst. The combustion tests of three kinds of oil shale semi-coke were carried out in a tube furnace to obtain the ash samples with different combustion end temperature. Then the functional groups of the samples were measured and analyzed by Fourier transform infrared spectrometer (FTIR). The results show that the infrared spectra of the three kinds of char are similar, but the peak intensity of partial absorption peak is different, and the vibration absorption in hydroxyl region is very weak, and there is no obvious carboxyl vibration absorption in semi-coke. With the deepening of combustion, the vibrational absorption peak of hydroxyl region gradually disappeared, the relative content of C-O bond of phenol, alcohol, ether and ester showed an increasing trend, and the carbonyl content fluctuated. At the same time, the vibration absorption of the aromatic skeleton becomes weaker with the combustion, and the C-H bond of the fatty hydrocarbon decreases with the oxidation consumption. Finally, on the basis of combustion test in tubular furnace, the pore structure characteristics of oil shale semi-coke with different combustion temperatures were studied by nitrogen isothermal adsorption and desorption method. The complexity of the surface morphology of the char and its combustion ash sample is described by fractal dimension. The results show that the pore structure of oil shale semi-coke is mostly fracture-shaped, and the mesoporous and micropore are the most. In the combustion process, the specific surface area decreases, increases and decreases, the micropore and mesopore in the particle play a decisive role in the change of the specific surface area. The fractal dimension obtained by linear regression of FHH equation shows that the pore characteristics of Wangqing oil shale semi-coke and Longkou oil shale semi-coke vary uniformly during combustion process.
【学位授予单位】：东北电力大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X742

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