Study On Release Characteristics Of Volatile Organic Compounds During Biomass Combustion

In order to provide scientific basis for volatile organic compounds(VOC)emissions reduction in biomass combustion process to reduce damage of VOC on human life and natural environment,the thesis focuses on the release characteristics and mechanism research of VOC in biomass combustion process,experimental research work of this paper is as follows:Firstly,the combustion characteristics and product releasing regular of biomass and its components were studied by using TG-FTIR-GC/MS technique.Owing to many side chains in xylan structure which were unstable,the weight loss of xylan initially started.The combustion temperature of lignin was the most extensive,and there were a large number of char involved in combustion in the process of fixed carbon combustion,which was formed due to the crack of side chain and condensation reaction.During low temperature combustion,cellulose and xylan produced a large amount of furans and levoglucosan,but with the increase of temperature,the content of aromatic compounds increased significantly.The gas produced by low temperature combustion of lignin was mainly CO2,VOC produced by high temperature combustion increased obviously,and all of them were aromatic compounds.Furthermore,the release regular of VOC from biomass and its components combustion at 600 ℃ was studied by Py-GC/MS technique.Combustion at 600 ℃,cellulose and xylan would produce alcohols,ketones,esters,aliphatic compounds and furan compounds with alcohols and ketones accounting for the maximum proportion.The different matter was that levoglucosan,levoglucosenone and 1,4:3,6-dianhydro-,alpha,-d-glucopyranose from cellulose combustion occupied a higher proportion,but hemicellulose combustion produced esters and anhydrosugar respectively containing 5.28%and 4.55%.The VOC from lignin combustion were aromatic compounds containing guaiacyl or syringyl,without polycyclic aromatic hydrocarbon(PAHs).PAHs in wood combustion products were the products of the carbonization,chemical conversion and rearrangement reaction during cellulose and hemicellulose combustion.Finally,the constant temperature combustion experiments of biomass and its components were carried out on the tubular resistance furnace.It was found that the combustion of biomass and its components would produce 11 kinds of VOCs such as alcohols,aldehydes,ketones,acids,phenols,esters,ethers,furans,dehydrated sugars,aliphatic and aromatic compounds.Alcohols,phenols,aldehydes,esters,furan,dehydrated sugar,aliphatic and aromatic compounds were the main volatile products of biomass and its components combustion.Contrasted with non-aromatic compounds decreased with rising temperature,the content of aromatic compounds increased with temperature’s up.