海南制浆树种中主要成分的近红外分析与模型优化

为提高制浆树种的利用效率,缓解国内制浆造纸原料短缺的现状,降低行业污染与总体成本,尝试将近红外光谱技术用于海南省制浆树种的成分含量分析,以期根据实时所得成分含量相应调整工艺参数.用结构简单、易改装的全息光栅分光近红外光谱仪采集了海南省常见的适龄制浆树种(尾细桉、尾巨桉、尾叶桉、马占相思和粗果相思)共205个样本的近红外...

Near-Infrared Analysis and Models Optimization of Main Components in Pulpwood of Hainan Province

In order to improve the utilization efficiency of pulpwood in Hainan Province,alleviate the shortage of domestic pulping and papermaking materials,and reduce pollution and overall costs in the pulping and papermaking industry,this study aimed to use near-infrared spectroscopy for the analysis of pulpwood.A holographic grating spectroscopic near-infrared spectrometer with a simple structure and easy modification was used to collect the near-infrared spectrum of 205 samples of pulpwood common in Hainan(E.urophlla×E.tereticornis,Eucalyptus urophylla×grandis,Eucalyptus urophylla,Acacia mangium,Acacia crassicarpa Benth.),and the content of holocellulose and lignin were measured according to the traditional laboratory methods.Suitable pretreatment methods were selected in combination with partial least squares to establish analysis models holocellulose and lignin.Then genetic algorithm was usedto eliminate the irrelevant variables and clarifythe feature absorption of holocellulose and lignin in order to optimize the models.The holocellulose model was established by pretreatment methods of Savitzky-Golay 13 points 3 times smoothing,vector normalization,the first derivative of the original spectrum,with1150.3~2362.0 nm bands participated in modeling.The optimal bands included the characteristic absorption of cellulose such as the 2 nd overtone of C—H stretching vibration in CH₃ between 1188~1196 nm,the 1 st overtone of O—H stretching vibration between 1742~1633 nm,the group frequencies of formation and stretching vibration of O—H near 2112 nm.The optimal bands also included the characteristic absorption of pentosan such as the 1 st overtone absorption of O—H stretching vibration between 1470~1495 nm,and the 2 nd overtone absorptionof C=O stretchingvibrationaround1906 and1911 nm.TheRMSEPvalueofthemodelwas0.55%,and the absolute deviation range was-0.91%~0.87%.The lignin model was established by pretreatment methods of Savitzky-Golay 13 points 3 times smoothing,MSC,the second derivative of the original spectrum,with 1137.6~1872.5 and 2131.0~2424.1 nm bands participated in modeling.The optimal bands included the characteristic absorption of lignin such as the 2 nd overtone of the C—H stretching vibration in the benzene ring and in the CH₃ near 1143 nm,the 1 st overtone of the C—H stretching vibration in the benzene ring between 1670~1684 nm,the group frequencies of stretching vibration of C—H and C=O near 2205 nm.The RMSEP value of the model was 0.45%,and the absolute deviation range was-0.76%~0.79%.The two models’RPD values were 4.71 and 3.47,respectively,which can meet the actual needs of online quick analysis and measurement of the main components of pulpwood.At the same time,this study provides a theoretical basis for the establishment of a near-infrared characterization system for pulpwood,and has a significant significance for the near-infrared technology to help the pulping and papermaking industry to change from automation to intelligence.