油页岩干馏残渣与锯末混合燃烧实验研究

发布时间：2018-01-22 02:52

本文关键词： 油页岩干馏残渣锯末热重红外联用气体产物释放特性表面结构反应动力学　出处：《东北电力大学》2015年硕士论文　论文类型：学位论文

【摘要】：油页岩干馏残渣因其自身含有大量对环境造成危害的苯酚类、硫化物和多环芳香烃等污染物，已经成为制约油页岩工业发展的关键问题。针对其处理问题，本文提出以锯末与干馏残渣混烧的方案，基于热重红外联用技术和比表面积分析技术，对其混烧特性进行了深入研究，，主要研究内容包括：混烧基础燃烧特性、混烧气体产物释放规律分析、混烧表面形态特性分析和混烧反应动力学解析。在对燃料基础特性分析的基础上，研究了油页岩干馏残渣与锯末的燃烧特性和气体释放规律,深入探讨了燃料混合比及升温速率等因素对其混烧特性的影响。通过对燃烧TG-DTG曲线的分析，研究结果表明随着生物质的掺入，混合样品着火、燃尽温度降低，燃烧速率增加，明显改善其燃烧特性。随着升温速率的提高，混合样品的燃烧曲线向高温段迁移，着火和燃尽温度升高，但单位时间内的反应特性有所提高。Glam-Schmidt曲线与DTG曲线中峰的位置相对应，表征气体的析出规律。有机化合物多产生于锯末热解过程中；而无机物则产生于燃烧的各个阶段，以CO2和CO为主要产物，同时还有少量SO2和NOx。利用氮等温吸附脱附法研究了燃烧过程对油页岩干馏残渣和锯末混合物表面孔隙结构特性的影响，并应用分形维数来定量描述混合物表面形态的复杂程度。结果显示混合物各个孔径范围内的孔体积较干馏残渣明显减少，在水分析出段尤为明显，燃烧前期表面孔隙以中微孔为主，后期以中大孔和大孔为主；混合物的中微孔结构在挥发分燃烧阶段得到充分发展，比表面积在显著增大，对反应进程具有促进作用。通过FHH方程线性回归得到的分形维数反映出混合物内部孔隙的立体化程度比干馏残渣更高，燃烧阶段化学反应及力学作用的交替影响，引起分形维数随温度的变化。结合经典热力学理论和过渡态理论，应用热分析动力学方法对FWO方程和KAS方程进行了推导。应用同步解析的思想同时求取了反应机理函数和活化焓，并深入研究了油页岩干馏残渣与锯末混烧过程中活化熵和活化自由能的变化规律。研究结果表明两种计算方法所求解的结果呈现一致规律，更好地描述了各样品的燃烧反应动力学机理。为提高计算结果精度，应用改进的等转化率法对样品的活化能进行计算，其数值传统等转化率法计算结果相符，从而验证了等转化率法对于所选样品燃烧的可行性。
[Abstract]:Oil shale retort residue has become a key problem restricting the development of oil shale industry because of its large amount of pollutants such as phenol sulfide and polycyclic aromatic hydrocarbons which are harmful to the environment. Based on thermogravimetric infrared (TIR) and specific surface area analysis technology, the mixing characteristics of sawdust and dry distillation residue are studied in depth. The main research contents are as follows: the basic combustion characteristics of mixed combustion. The law of gas product release, the surface morphology and kinetics of mixed burning were analyzed. Based on the analysis of fuel basic characteristics, the combustion characteristics and gas release laws of oil shale retort residue and sawdust were studied. The effects of fuel mixing ratio and heating rate on the combustion characteristics were discussed in depth. Through the analysis of combustion TG-DTG curves, the results showed that the mixed samples were on fire with the addition of biomass. With the increase of the heating rate, the combustion curve of the mixed sample moved to the high temperature section, and the ignition and burnout temperature increased. But the reaction characteristics in unit time are improved. Glam-Schmidt curve corresponds to the position of peak in DTG curve. The organic compounds are produced in the pyrolysis process of sawdust. The inorganic compounds are produced in various stages of combustion, with CO2 and CO as the main products, and a small amount of SO2 and no _ x at the same time. The effect of combustion process on pore structure of oil shale mixture of dry distillation residue and sawdust was studied by isothermal adsorption and desorption of nitrogen. The fractal dimension is used to quantitatively describe the complex degree of the surface morphology of the mixture. The results show that the pore volume in each pore size range of the mixture is obviously reduced than that in the dry distillation residue, especially in the water analysis section. The surface pores are mainly mesoporous in the early stage of combustion, and mainly in the mesoporous and macropore in the later stage. The mesoporous structure of the mixture was fully developed during the combustion of volatile matter, and the specific surface area increased significantly. The fractal dimension obtained by linear regression of FHH equation shows that the three-dimensional degree of pores in the mixture is higher than that of dry distillation residue. The alternation of chemical reaction and mechanical action in combustion stage results in the change of fractal dimension with temperature. Based on the classical thermodynamic theory and transition state theory, the FWO equation and KAS equation are derived by using the kinetic method of thermal analysis. The reaction mechanism function and activation enthalpy are obtained simultaneously by using the idea of simultaneous analysis. The changes of activation entropy and activation free energy in the process of oil shale dry distillation residue and sawdust were studied. The results show that the results obtained by the two methods are consistent. The kinetic mechanism of combustion reaction of each sample is better described. In order to improve the accuracy of the calculation, the activation energy of the sample is calculated by using the improved equal-conversion method, and the calculated results are consistent with those calculated by the traditional numerical equal-conversion method. The feasibility of the iso-conversion method for the combustion of the selected sample is verified.
【学位授予单位】：东北电力大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X742;TQ038

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