Study On The Formation And Gasification Characteristics Of Yunnan Lignite

At present,focusing on the improvement of energy efficiency and environmental protection,more and more attention was made to efficient and coal-clean conversion and use.Briquette was an important coal-clean technology.China regarded briquette as an effective way to promote energy conservation.The pulverized coal is processed into briquettes not only can reduce the contradiction of lump insufficient resources,but also significantly reduce the dust pollution during the production process of pulverized coal.Lignite is the coal of low coal rank,which is a high volatile,high moisture,high ash content,low calorific value,low ash melting point of the low-quality coal,and it is not conducive to transport and use.Yunnan lignite made into briquette can be improving its utilization,effectively.The briquette thermal processing was one of the most important processes.The relationship between briquette chemical process study and thermal processing technology was very closely related.The achievements had a direct role in guiding the process of briquette gasification and the applications of coke and combustion-based.This dissertation first introduced the basic principle and application of pulverized coal molding and briquette pyrolysis and gasification,then reviewed the methods to improve the mechanical strength of briquette and the current research of briquette pyrolysis and gasification reactivity.In this thesis,the process of briquette molding and coal pyrolysis and gasification were elaborated,and using the response surface method to optimize the coal preparation conditions.The structure of briquette,performance of pyrolysis and gasification and gasification mechanism were characterized by contact angle,FTIR,BET and quantum chemical methods.The detailed works were shown as the following:1.As a binder raw material of starch,CaO,PVA,prepared the briquette by cold-forming.Studying the impact on the content of each component and the molding conditions for drop strength and cold strength and using the response surface method to optimize the preparation conditions.Studies show that the best condition is that the binder content is 14.49%,the temperature is 41.58 ?,and starch content is 15%,CaO/starch is 0.1,PVA/(CaO+ starch)is 0.1.2.This paper will explore the impact of content of each component on briquette pyrolysis and gasification using the binder cold forming way.The sample was heated from ambient temperature to 105?.Maintained isothermally after 20 min,the sample was then heated to a final temperature of 700 ? at a fixed heating rate of 10 ?/min in a nitrogen atmosphere.The volume flow rates of nitrogen and argon,as a protective gas,were 50 mL/min,respectively.And we will analysis the characteristics of briquette pyrolysis and gasification reaction based on thermal gravimetric analysis,infrared analysis,pore analysis and quantum chemical analytical tools.Research on coal pyrolysis and gasification characteristics shown that adding starch,calcium oxide and PVA components could improve coal pyrolysis and gasification reactivity and reaction rate.