Selecting the Pre-Hydrolysis Conditions for Eucalyptus Wood in A Fractional Exploitation Biorefining Scheme

The operating conditions for the autohydrolysis of eucalyptus wood were optimized with a view to maximizing hemicellulose extraction while preserving the integrity of glucan. The influence of the operating conditions used in the soda–anthraquinone pulping of the solid phase resulting from the autohydrolysis process was examined. Autohydrolysis of the raw material at a liquid/solid ratio of 8 kg water/kg material at 180°C for 30 min was found to provide a commercially useful liquid phase containing most of the starting hemicellulose. The autohydrolysis treatment allowed the subsequent production of soda–anthraquinone cellulose pulp and paper with properties as good as or even better than those obtained without the pretreatment.     

Organochlorine Formation in Tertiary Amine Catalyzed Pulp Bleaching

An oxygen delignified eucalyptus kraft pulp was bleached by applying a catalytic amount of a tertiary amine, 1,4-diazabicyclo[2,2,2]octane, and hypochlorous acid at varying pH, temperature, and time. The bleaching filtrate was analyzed for chloroform and AOX and the pulp for residual lignin, hexenuronic acid, and OX. In comparison with chlorine dioxide bleaching, the novel catalytic bleaching (pH < 6) generated only traces of chloroform and low contents of AOX and OX. Separate catalytic oxidations of authentic hexenuronic acid showed that it was a major precursor of chloroform. The results demonstrate a practical way to reduce organochlorine formation in pulp bleaching and provide new understanding on the reaction pathways that yield chloroform.     

英落菱镁矿选矿试验研究

针对菱镁矿矿石中脉石杂质的赋存特点，采用常规反正浮流程，使用Ｎａ２ＣＯ３反浮矿浆调浆，六偏磷酸钠加水玻璃抑制白云石和硅酸盐脉石杂质，并结合浮选前脱泥的工艺，达到了镁钙硅有效分离的目的，较常规工艺提高了浮选精矿指标。     

一步法二甲醚合成技术

二甲醚是一种非常重要的化工原料,可用于多种精细化学品的合成,它是一种理想的清洁替代能源。一步法二甲醚合成技术克服了甲醇合成反应受到热力学平衡的限制,大大提高了CO的单程转化率。对以合成气为原料采用一步法二甲醚合成技术的反应原理,催化剂的组成与制备方法,温度、压力、空速等因素对反应造成的影响进行描述。对一步法二甲醚合成技术研发的生产装置发展进程情况进行综述和展望。     

Preliminary Studies on Furfural Production from Lignocellulosics

This study focused on the production of furfural from agricultural and industrial biomass residues by a hydrodistillation process. Corncobs, sugarcane bagasse, and eucalypt wood were treated with sulfuric, hydrochloric, and phosphoric acids as catalysts, with different acid concentrations (1.5 to 5.2 mol.L ^?1). In addition, the eucalypt liquor from the auto-hydrolysis, kraft-dissolving pulp production process was also investigated as a source of furfural, using sulfuric and hydrochloric acids as a catalyst (0.9 and 3.9 mol.L ^?1) . Furfural yields of 30.2, 25.8, and 13.9% were achieved for corncob, sugarcane bagasse, and eucalypt wood, respectively, on the basis of biomass dry weight. The efficiency of conversion from pentose to furfural using eucalypt liquor from the auto-hydrolysis kraft process was 71.5% using HCl 3.9 mol.L ^?1 . Due to the presence of a high amount of pentose, corncob produced the highest amount of furfural, followed by sugarcane bagasse and then eucalypt wood.     

Simulation analysis of producing xylitol from hemicelluloses of pre-hydrolysis liquor

The pre-hydrolysis liquor (PHL) of the kraft-based dissolving pulp production process is currently sent to the recovery boiler and incinerated. However, PHL contains about 5–8% lignocelluloses that can be utilized in the production of value-added chemicals. In this study, a process for producing xylitol from hemicelluloses in PHL is developed. This process involves several acidification, neutralization, adsorption (along with reactivation) and evaporation stages. The mass balance indicates that 533 kg/h xylitol (with 99% purity), 187 kg/h lignin, 806 kg/h basic ferric acetate, and 1600 kg/h gypsum can be produced from 41,670 kg/h PHL. The energy balance shows that the evaporators are the largest consumers of energy, while the reactivation kiln, acidification, neutralization, and precipitation processes generate some heat. Overall, 41% conversion of xylose to xylitol is achieved.     

芳纶标准回潮率测试方法的改进

针对现有GB/T 6503—2008测试纤维回潮率的缺陷,提出测试芳纶标准回潮率的改进方法:采用烘箱法先将纤维试样在烘箱中烘至恒重,然后将烘至恒重的试样在标准大气条件下调湿至平衡状态,最后将调湿平衡的试样在烘箱中烘至恒重,测试芳纶的标准回潮率。结果表明:该方法中起初的预烘干处理消除了芳纶表面的油剂等对测试有干扰的因素,测得的标准回潮率更准确,标准回潮率的相对标准偏差为0.64%,方法的重复性好。     

基于COMSOL的纸浆模塑干燥模拟及验证

目的 研究采用COMSOL Multiphysics模拟纸浆模塑干燥效率及厚度变化的可行性。方法 基于多孔介质理论,应用有限元仿真软件COMSOL Multiphysics建立纸浆模塑干基含水率随时间变化的热湿、水分流动、非等温流动多物理场耦合模型,考虑干燥中含湿多孔介质的湿空气热对流及多孔基体的热传导,模拟在热板加热条件下纸浆模塑的干燥效率和厚度的变化,并与实验结果进行比较。结果 模型内域探针所得模拟结果与实验结果具有良好的一致性,在干燥后期厚度预测误差范围为0.4%～7.7%,干燥效率预测差异值最低为4.3%。结论 采用COMSOL Multiphysics模拟纸浆模塑干燥过程可行。     

纸浆模塑品缓冲性能影响因素的仿真研究

目的 研究形状、结构参数对纸浆模塑品承载和缓冲性能的影响,为纸浆模塑品缓冲结构设计提供更多参考。方法 通过拉伸试验得到材料物理性能参数。对不同形状单元进行静态压缩试验和有限元模拟,对比验证仿真的可靠性。利用Ansys Workbench/LS-DYNA对3种不同形状单元以及3个结构因素的四棱台进行动态冲击模拟,评价其承载性能,并从能量吸收方面评价缓冲性能。结果 不同形状单元中,圆台的承载和缓冲性能最佳;随着斜度增大,极限载荷和吸能性能整体呈下降趋势,1°时四棱台单元极限载荷最大,4°次之,1°~4°时吸能性能较好且变化相对稳定;随着长宽比增大,极限载荷和能量吸收整体均呈现下降趋势;极限载荷随着高度增加而减少,高度在10~25 mm时能量吸收不断减少,在25~40 mm时不断增加,在30~40 mm时单位体积吸能较稳定。结论 在设计缓冲结构时,尽可能选择圆台状单元,斜度在1°时最佳,4°次之,长宽比在1~1.5最佳,高度在30~40 mm较好。     

纸家具的结构和应用形式分析

本文探讨了纸家具的基本特性、结构及纸质材料在家具中的应用形式.通过对纸家具环保性、经济性和舒适性等基本特征的分析,总结了纸家具的层叠结构、插接结构、折叠结构等典型结构和纸浆模塑一体结构、糊纸结构、五金件连接结构等新型结构的基本形式和特点,探讨了纸质材料在纸家具中的应用方向和途径,探索了纸家具的研究前景和方向,即应从纸家...