Effect Of Ash Melting On Combustion Reactivity Of Biomass Formed Particles During Combustion

Biomass energy reserves are very rich,compared with traditional fossil energy,it has great environmental protection advantages.It is a renewable energy.It is very important for the development and utilization of biomass energy.Biomass pellet combustion is an important way of utilization in the development and utilization of biomass.However,in the combustion process of biomass briquette particles,ash will melt,which will affect the combustion reactivity of particles.Therefore,it is necessary to clarify this effect in order to use biomass more scientifically and effectively to alleviate the current energy and environmental problems.In this paper,the ash melting characteristics and reactivity changes of four biomass granules,namely peanut hull forming granules?normal,mixed with ash and water washing,the same below?,wheat straw forming granules,corn straw forming granules and rice hull forming granules,were studied,which laid a foundation for efficient combustion of biomass forming granules in practical combustion equipment.Firstly,in the industrial analysis and elemental analysis of biomass raw materials,it was found that the volatile content of the four kinds of biomass was high,about66%,the fixed carbon content was low,and the S element content was low.It was found that the four characteristic temperatures of rice husk were all higher than1500?,while the other three biomass were between 1100?and 1300?.Secondly,the combination of macroscopic observation and microscopic analysis is used to study the melting phenomenon of ash in the combustion process and the internal mechanism of ash fusion.Under the high-speed camera,it was found that at the temperatures of 1100?and 1300?,except for the rice husk,the other three biomasses melted under most conditions.After SEM analysis,all the experimental particles at both temperatures melted.XRD and EDS analysis found that the main substances in the ash sample were KCl,SiO₂,CaCO₃,MgO,Fe₂O₃ and various alkali metal and alkaline earth metal silicates.The samples in different samples have large differences,and the elements at different temperatures.The form of existence is very different.The large amount of KCl is the main factor for the ash fusion in the combustion of wheat straw and corn stover particles,while the melting of peanut shell granules and rice husk granules is related to the low melting point alkali metal and alkaline earth metal silicate;It is related to SiO₂,CaCO₃ and high melting point silicates.In addition,in the previous macroscopic observation,no molten rice husk granules and peanut shell ash particles at 1100?were found to have the presence of molten ash under electron microscope.Finally,the thermogravimetric test was carried out on the high temperature and large particle thermogravimetric test bench.Through the qualitative and quantitative analysis of the thermogravimetric results,it was found that at 1300?,the ash melted on the peanut hull,wheat straw and corn stalk.The combustion played a promoting role,and the rice hull granules inhibited it;at 1100?,the ash fusion promoted the peanut hull granules and inhibited wheat stalks,corn stalks and rice hull granules.