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微型反应器中半焦催化焦油重整反应的特性和动力学
MOHAMMED HARUNA ADAMU
Thesis Advisor曾玺
2020-07-01
Degree Grantor中国科学院大学
Degree Name硕士
Degree Discipline化学工程
Keyword气化,焦油,热裂解,催化重整,微型流化床
Abstract

气化技术是含碳燃料清洁、高效转化的主要途径。煤焦油是中低温气化技术不可避免的液体副产物。低温下,焦油凝结,易堵塞管路、腐蚀设备、引起催化剂中毒、并产生大量含酚废水,影响设备的正常运行,且降低气化效率。研究表明,半焦能有效地脱除焦油,且具有来源广、成本低、失活后可继续用于气化等优势。然而,现有的相关研究大多集中在半焦脱除焦油的可行性论证和焦油脱除效率的改进上,而对半焦脱除焦油的机理和动力学研究较少,制约着该技术的发展,亟待研究。基于此,本研究利用热重(TGA)和微型流化床反应分析仪(micro fluidized bed reaction analyzer )考察多孔煤焦对煤焦油的等温和非等温催化脱除作用,与煤焦油的热裂解作用相比,证明半焦催化脱除的优势,揭示半焦中金属氧化物对焦油脱除的贡献,利用绝对转化率方法求算半焦催化脱除焦油过程中气体生成的动力学数据。具体如下:首先,利用热重分析仪考察了非等温条件下(50-1000 ℃)煤焦油热裂解过程和催化重整过程的质量演变规律,对比在上述过程中焦油的热化学反应行为,计算基于焦油质量变化的反应动力学,两者的反应活化能分别为27.38和18.47 kJ/mol,证明半焦对焦油的催化重整作用。其次,利用新开发的微型流化床反应分析仪考察等温条件下,焦油热裂解和焦油催化重整的反应行为。为模拟多孔半焦中金属氧化物的催化效果,制备无灰分半焦和负载单一金属氧化物的半焦催化剂,考察其催化效果,并与热裂解和含灰半焦进行比较。并基于对气体产物的分析(H2,CO,CO2和CH4),进行动力学计算,揭示金属氧化物的贡献及半焦序列依次为:CaO > K2O > Fe2O3 > Na2O > MgO。基于此,提出半焦催化焦油的均相和非均相反应机制。;Gasification is regarded as a promising method for the conversion of coal and carbonaceous materials into syngas and fuel gas. However, despite the production of useful products, some undesirable contaminants such as tar, are inevitably produced as by-products which brings problems to the whole gasification process such as blocking and corroding of pipes and equipment, poisoning of catalyst, and the production of phenolic wastewater and irritating gases that contributes to severe environmental problems. In recent years, tar removal by char catalytic reforming has been widely considered as a feasible catalyst with a good technical and economical property. Being an intermediate product in the gasifier, char owns obvious advantages, such as cheapness, abundance, good reactivity, strong resistance in sulfur and chlorine to avoid poisoning, and no consideration of catalyst regeneration after deactivation. All of these characteristics make char a good catalyst for tar removal in a commercial gasifier. However, the existing reports mainly focus on the feasibility research on tar removal by char and the improvement of tar removal efficiency. Researches about the mechanism of tar catalytic removal and the reaction kinetics are very few, strongly inhibiting the rapid development of this novel tar removal technology.To reveal the reaction characteristics of tar catalytic reforming by char, a TGA and newly developed micro fluidized bed reaction analyzer (MFBRA) were adopted in this study. The non-isothermal and isothermal reaction behavior were analyzed and compared. Moreover, to verify the advantages of char catalytic reforming by char, the thermal cracking of tar was also examined.This thesis primarily investigates the characteristics, role of metal oxides and kinetics of tar catalytic reforming by char in a newly developed micro fluidized reaction analyzer (MFRBA) with the aim to expand the understanding of tar catalytic reforming and to propose kinetic models for fuel gas production.The non-isothermal cracking behavior of tar by char was firstly investigated and compared with results realized by non-isothermal cracking behavior in TGA. Under the experimental conditions, the temperature and char property were considered the key factors that efficiently promote the tar cracking reaction. While, the activation energies for thermal cracking and catalytic reforming by char were 27.38 and 18.47 kJ/mol respectively. 

Language中文
Document Type学位论文
Identifierhttp://ir.ipe.ac.cn/handle/122111/49648
Collection中国科学院过程工程研究所
Recommended Citation
GB/T 7714
MOHAMMED HARUNA ADAMU. 微型反应器中半焦催化焦油重整反应的特性和动力学[D]. 中国科学院大学,2020.
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