高温燃烧热导法中木质纤维素主元素分析条件优化

Optimization of Principal Elements Analysis Conditions of Lignocellulose by Response Surface Methodology in Thermal Conductivity Method of High Temperature Combustion

中文关键词:  木质纤维素  主元素分析  高温燃烧热导法  响应面法

Key Words:lignocellulose  principal elemental analysis  high temperature combustion thermal conductivity method  response surface method

中文摘要:

      为准确测定木质纤维素的主元素含量，本研究基于高温燃烧热导法测定煤主元素的分析条件，采用二阶因子法筛选得到木质纤维素主元素含量测定的4个显著影响因素，其对木质纤维素主元素含量测定的影响由大到小依次为：供氧时间、供氧流量、样品质量、燃烧管温度；并通过单因素实验和响应面法优化测试参数，所得最佳实验条件为：样品质量30 mg、供氧时间90 s、供氧流量100 mL/min、燃烧管温度950 ℃。在最佳测试条件下，对6种木质纤维素标准物质进行主元素分析，并与煤测试条件和国家标准规定的方法对比。结果表明，优化后木质纤维素主元素分析条件的准确度与精确度均优于煤测试条件和国家标准规定的方法，主元素含量测定的标准偏差均<0.2，符合碳、氢、氮、硫4种主元素含量测定标准偏差≤0.3的目标要求，相对标准偏差（RSD，n=6）在0.04%~1.35%范围内。

Abstract:

      In order to accurately determine lignocellulosic main element content， in this study， based on the analytical conditions for the determination of coal main element by thermal conductivity method of high temperature combustion， four significant influencing factors of determination of lignocellulosic main element content were selected by second-order factor method. The effects of significant influencing factors on the determination of lignocellulosic main element content were in descending order as follows： oxygen supply time， oxygen supply flow， sample mass and combustion tube temperature. The test parameters were optimized by single factor experiment and response surface method. The optimum experimental conditions were as follows： sample mass was 30 mg， oxygen supply time was 90 s， oxygen supply flow was 100 mL/min， and combustion tube temperature was 950 ℃. The main element analysis of 6 lignocellulosic standard substances was carried out under the optimum test conditions， and compared with coal test conditions and national standard method. The results showed that the accuracy and precision of the optimized lignocellulose main element analysis conditions were superior to the coal test conditions and the national standard method. The standard deviation of the main element content determination <0.2， meeting target requirement for standard deviation ≤0.3 in C， H， N， S content determination， and the relative standard deviation （RSD， n=6） was in the range of 0.04%~1.35%.