The Production Of Lignin From Xylo-oligosaccharides Residues And Its Application

As the rapid development of global economic and the rapid growth of the fossilenergy consumption, the widespread use of fossil fuels, has brought numerous benefitsto industrialized societies, and this lead to the energy supply cannot meet therequirements of sustainable development. Now biofuel holds special appeal because it isrenewable, well-sourced and less pollution to the environment around the world. InChina, straw materials, especially the agricuture residues, are more abundant. Usually, itis discarded as garbage or burned directly for heat. Thus, It cause the awful waste ofresources and sever environmental pollution.Xylo-oligosaccharide is a kind of functional oligosaccharide, its industrialproduction scale is expanding. In this paper, Xylo-oligosaccharides residues werestudied by NREL methord. Firstly, the main composition of Xylo-oligosaccharidesresidues can be determined. Secondly, we discusses the different liquid-solid ratio,extraction temperature and pH of precipitation influence the lignin extraction yield.Through the orthogonal experiment, we obtain the optimal scheme of extracting lignin.Which is the process of liquid-solid ratio1:8, extraction temperature is80℃,precipitation under the condition of pH=3, obtained the highest lignin yield (15.89%). Itcould be extracted more than61%lignin separation from Xylo-oligosaccharidesresidues, through infrared spectrometry showed that the extracted lignin has typicalaromatic ring structure, containing three kinds of structure unit（syringa, guaiac, andhydroxy phenyl）. It belongs to the herbs lignin, and has more than95%purity. Inaddition, after extracting lignin, the main composition of residue is cellulose, using itsfermentation to produce bio-ethanol can reduce enzyme amount, improve the efficiencyof enzymatic hydrolysis.The lignin can be used for producing lignosulfonate used asdye dispersants by sulfonated modified.At the same time, we also studied sulfonation modification the extracted ligninprocess. Orthogonal experimental results show that the sulfonating agent amount ofadding anhydrous sodium sulfite is the main factors affecting the effects of sulfonated,other was followed by the reaction time and reaction temperature. The best sulphonatedtechnology conditions as follows: the amount of adding sodium sulfite was15%, thetemperature is95℃, sulfonated time for7h. The property of lignosulfonate has thebetter function, and it can be used for water reducing agent and dispersant type ofsurfactants. In order to further improve the addition-value of lignin, the lignosulfonate processwere produced with scale-up pilot. From the100g of lignin/batch up to900kg/batch oflignin, lignosulphonate sodium was obtained after spray drying. The result of analyzeproducts show that the lignosulphonate has0.66of sulfonated degree, which can beused as dispersant type surfactant application, has certain market prospects. Comparedwith similar products at home and abroad, although there are still some shortage, butstill has certain market competitiveness.