Study On Structure And Combustion Pyrolysis Characteristics Of Tobacco Cellulose

Tobacco cellulose is the main component of tobacco cell wall,and also the most abundant carbohydrate in tobacco,its content in tobacco leaves is generally about 11%,which is the basic material of tobacco tissue and skeleton.Tobacco cellulose produces many low-grade aldehydes after it burn,which will bring adverse effect on the sensory quality of tobacco.Therefore,it is important to study the structure information and combustion pyrolysis characteristics of tobacco cellulose,for the evaluation of tobacco quality and tobacco industry’ work of reducing tar and toxic.At present,there are still some problems in the purification methods and structural analysis methods of tobacco cellulose,and the research on their relationship has not been reported.So,the study of tobacco cellulose’s structure and its combustion pyrolysis characteristics can provide a reliable microstructure theory for the deep study of tobacco cellulose’s pyrolysis characteristics,which further can reveals the effect of tobacco cellulose structure on its quality.In this paper,tobacco cellulose was further purified,and a more accurate method of structural characterization was established.This method has been detected different tobacco samples.Pyrolysis process and pyrolysis products were studied by thermal analysis technique,and different tobacco samples’ pyrolysis characteristics were discussed in detail.On the basis of making full use of the relevant literature,the following studies were carried out:First of all,in order to get purity tobacco cellulose samples,Lignin and hemicellulose has been removed after pickling washing.A method utilizing CP/MAS 13C NMR spectra was developed for the structure analysis of cellulose in tobacco samples.The NMR spectra in combination with spectral fitting were analyzed in detail and some structure parameters such as the cellulose crystallinity,allomorph composition and lateral dimensions for cellulose elementary fibrils and microfibrils were determined.The results showed that the main allomorph composition in tobacco cellulose was Iβ obtained by the spectral fitting for the cellulose.The cellulose crystallinity calculated by the spectral fitting was about 50%.The lateral dimensions for cellulose elementary fibrils and microfibrils were in the range of 3.0-6.0nm and 6.0-13.0nm,respectively.This results were consistent with the results of XRD.The method has high accuracy and can be used for rapid analysis of cellulose crystal structure in tobacco samples.Secondly,in order to study the combustion and pyrolysis characteristics of tobacco cellulose with different structures,cellulose from flue-cured tobacco,burley tobacco,oriental tobacco and tobacco stem was extracted and then its crystal structure was characterized.Combustion behavior under N2 and 10%O2 atmosphere were studied using thermogravimetric and pyrolysis process were studied by micro combustion calorimeter.And the relationship between structure and pyrolysis behavior was studied for the first time.There were significant differences in cellulose structure among different types of tobacco,in which oriental tobacco cellulose had higher crystallinity,crystal fiber content,fibrillar surface and base of the original sizeespecially.So,the flammability of oriental tobacco cellulose was poor,its thermal stability was the worst at low temperature,but it had the highest carbon residue at high temperature.Finally,pyrolysis product composition and carbonyl compound release were studied by Pyrolysis-gas chromatography/mass spectrometry and off-line furnace pyrolysis device.The relationship between structure and pyrolysis product was studied for the first time.The results showed that the pyrolysis products different kinds of tobacco cellulose samples were mainly aldehydes,ketones,furan,dehydrated saccharides,and a small amount of alcohols,esters and aromatic compounds,the difference was mainly in the concent of each pyrolysis products;The total release of the compound and the release of each carbonyl compound showed an increasing trend with the increase of temperature.However,the release of carbonyl compounds from oriental tobacco cellulose is slightly different from the other three tobacco cellulose,due to its minimum size of base fibrillation clusterIn this article,structural characteristics and pyrolysis characteristics of tobacco cellulose has been studied.Lay the foundation for further study on the effect of the structure on the pyrolysis mechanism of tobacco cellulose.