硫酸盐竹浆ECF漂白过程中糖类组分变化的研究

应用高效液相色谱法研究了硫酸盐竹浆 ECF 漂白过程中二氧化氯漂白段糖类组分的变化情况。结果表明,葡聚糖、木聚糖和阿拉伯聚糖在二氧化氯漂白过程中有不同的降解率,葡聚糖降解率只有 0.133%,而木聚糖的降解率为 0.907%,阿拉伯聚糖的降解率达 79.77%,明显高于葡聚糖的降解率。     

机械处理方法对竹浆性能的影响

利用双螺杆挤压搓揉机搓揉结合KRK高浓磨浆机磨浆的组合机械处理方法对蒸煮物料成浆方式进行了研究,探讨了搓揉-磨浆组合成浆方式对竹浆纤维形态及物理性能的影响.结果表明,在实验条件下,由这种组合成浆方式获得的竹浆纤维长度最长可达1.786m m,抄成的纸张的最大裂断长为5.70 km.撕裂指数和耐破指数分别为11.7 mN...     

使用竹浆、纸改浆出现的问题及解决措施

竹浆、纸改浆以15％比例使用后,给制胶、纺炼、酸站各工序带来了不良影响,出现了不少工艺问题且影响到粘胶短纤维成品质量。经过采取一系列技术措施后,出现的问题得到有效解决,竹浆、纸改浆投用比例达到30％以上,产品优级品率在99．5％以上。     

竹浆酸处理工艺及其对竹浆粕纤维素性能的影响

探讨了pH值、温度、时间、浆浓以及螯合剂对酸处理工艺的影响效果,优化酸处理工艺条件,并应用于竹浆粕制备过程,分析了竹浆粕酸处理前后的纤维素性能变化。结果表明,通过对漂白竹浆灰分及黏度下降率变化规律的分析,获得酸处理最优的工艺为:pH值3.0、温度50℃、时间30min、浆浓5%、DTPA用量0.5%;通过酸处理前后绿竹浆粕性能的对比,表明酸处理可进一步提高浆粕α-纤维素纯度,显著降低灰分含量,调整浆粕聚合度范围,提高并稳定浆粕白度,从而改善浆粕质量。     

栀子对竹浆纤维的染色性能

首先对栀子色素提取工艺进行优化研究,得出最佳提取条件,然后通过正交试验及单因素试验对竹浆纤维进行直接法、后媒法染色,测试染色后纤维的上染率、固着率、上染速率以及各项色牢度。根据分析试验结果,最终确定了竹浆纤维最佳的染色工艺。研究结果表明,栀子的最佳染色法是直接染色法,其最优工艺条件是温度80°C,染液质量浓度3／4X,pH=8,时间为5min时上染速率达到最大值。     

浆粕性质对离子液体法再生竹浆纤维性能的影响

以6种不同性质的竹浆粕为原料,选用1-乙基-3-甲基咪唑醋酸盐{[EMIM] Ac]为溶剂,采用干喷湿纺的方式制备了再生竹浆纤维,探讨了竹浆粕性质对再生竹浆纤维制备过程中溶解、流变行为以及纤维性能的影响.结果表明:离子液体对竹浆粕具有非常强的溶解能力;6种竹浆粕/[EMIM] Ac纺丝液都属于切力变稀流体;高聚合度和高α纤维素的竹浆粕制备的纤维的断裂强度和模量较高,但是纺丝过程不连续,发生断头较多.     

Co-salen型仿酶系统催化漂白竹浆最优化工艺条件的研究

采用正交试验方法对竹浆Co-salen型仿酶系统催化漂白竹浆最优工艺条件及影响因素进行了研究。用白度、硬度、黏度和选择性这四个指标评价仿酶预处理的效果,并通过计算确定了各因子的影响程度及最佳因子组合。结果表明,竹浆Co-salen仿酶催化预处理较适宜的条件为:NaOH用量3.0%,H2O2用量1.0%,Co-salen用量0.03%,吡啶用量0.007%,温度90℃,时间5 h,氧压0.2 MPa,浆浓5%。     

竹浆纤维的性能及发展前景

竹浆纤维又称再生纤维素纤维,是一种新型的绿色健康纺织原料。由于其特殊的性能成为国内纺织开发的热点之一,具有极大的开发前景。介绍了竹浆纤维的性能特点、生产工艺过程以及目前存在的问题,展望了竹浆纤维的发展前景和趋势。     

竹浆分批加酶工艺对长时间纤维素酶解性能的影响

优化纤维素酶水解工艺对于纤维素的高效利用具有重要意义。实验在保证纤维素酶相同的添加量时,采用多种方式分批添加纤维素酶水解竹浆,在长时间(7 d)的酶解过程中测定每天还原性糖产量,最后对长时间酶解过程中的影响因素进行了探究。实验结果表明:采用(0.35 mL+0.15 mL+0.1mL)添加工艺提高了酶解效率,酶解7d后糖产量提高了4.36%;纤维素酶随着培育时间的进行活性不断减小,培育1 d后的酶活性仅为原酶活性的53.87%;酶解糖产量随葡萄糖浓度的增加而降低,当葡萄糖浓度为30 mg/mL时,糖产量较无葡萄糖实验组降低了30.7%。酶解过程中酶活的丧失以及底物的抑制可能是影响纤维素酶长时间水解过程中的重要因素。     

黔北20万吨竹浆纸一体化工程顺利通过国家环保验收

12月3至4日,国家环境保护部组织西南环保督查中心、省环保厅、遵义市环保局、赤水市环保局、习水县环保局对黔北20万吨竹浆林纸一体化工程进行现场检查验收。参加验收的单位还有中国环境监测总站、环保部环境工程评估中心、省环保监测中心站、纸业公司安环部等单位,验收组的20多位领导和专家以高度负责的精神,通过听取汇报、查阅资料和实地考察,对工程进行了全面检查验收。     

竹浆造纸用化学品

竹材作为一种优良的非木材纤维原料用于造纸,不仅具有资源优势,还具有较好的成本和质量优势。本文介绍了各种化学品在竹材制浆造纸过程中的应用。     

Effect of Xylanase and Dosage on the Refining Properties of Unbleached Softwood Kraft Pulp

Abstract

Two xylanase preparations were compared at different doses for their abilities to enhance the refining properties of a never-dried, unbleached kraft pulp derived from radiata pine. These enzymes varied in their ability to solubilise xylan from pulp, and the selective removal of pulp xylan did not reduce intrinsic fibre strength. At low levels of xylan solubilisation, there were increases in sheet densification after PFI refining without change in tensile and tear strength at a given sheet density, indicating lower pulp refining requirements. At high levels of xylan solubilisation, the level of sheet densification was greater but there was a small decrease in tensile strength at a given sheet density and an increase in tear strength. One of the xylanases yielded a selective increase in tear strength at a given tensile strength.     

Effects of Different Microorganisms on Pulp and Paper Properties

Pretreatment of wood chips with some microorganisms including white-rot fungi and streptomyces improves the strength properties of mechanical pulps. We studied the effect of these white-rot fungi and streptomyces on the mechanical properties of handsheets. Strength and optical properties were compared in handsheets prepared from mechanical pulp of treated and untreated wood chips. The fungal pretreatments resulted in handsheet strength properties better than the control and also better than streptomyces when compared at an equivalent freeness. Fungal pretreatments decreased brightness and light-scattering coefficients but did not adversely affect opacity. Lignin content of the chips was reduced by fungal pretreatments.     

高纯耐热耐碱木聚糖酶预处理对杨木KP浆漂白特性的影响

研究了耐热耐碱木聚糖酶X对杨木硫酸盐浆预处理的选择性及其对无元素氯(ECF)漂白特性的影响。结果表明:该木聚糖酶预处理具有高的助漂选择性,预处理对纸浆的得率及黏度影响不大;该木聚糖酶对温度及pH的适应范围较广,在温度为75～80℃、pH 8.0～9.5范围内都可以发挥有效的助漂作用,尤其在温度80℃、pH 8.0、酶用量2 IU/g的条件下更能发挥酶效;耐热耐碱木聚糖酶X预处理可减少漂白ClO2用量,当达到对照浆相同白度(90%ISO)时可减少D0段26%～27%的ClO2用量(相当于总用氯量的16%)。     

枫香树材硫酸盐法蒸煮历程

研究了枫香树材硫酸盐法蒸煮过程中木素、戊聚糖和纸浆得率的变化。结果表明,枫香硫酸盐法蒸煮脱木素可分为以下三个阶段:第一阶段,升温到155℃,属于初始脱木素阶段,木素脱除率达到22.5%左右,戊聚糖溶出30.16%,得率为70.48%;第二阶段,从155℃开始到165℃保温60 min,属于大量脱木素阶段,木素脱除率达93.74%,戊聚糖溶出48.31%,得率为47.43%;第三阶段,从165℃保温60 min后到蒸煮末期,属于残余脱木素阶段,木素脱除率达到98%左右,戊聚糖溶出51.04%,得率为43.87%。     

Dissolution of Lignin from Kraft Pulp after Treatment with Nitrogen Oxides

Laboratory experiments show that pretreatment with NO₂ including heating and ripening at 5% consistency and 90°C for 3 hours in the presence of NO₃- and H⁺ led to a dissolution of approximately 50–60% of the lignin in unbleached kraft pulp. Only 5–15% were dissolved when the treatment was terminated after heating to 90°C. An extensive fragmentation of the lignin during the ripening explains the extensive delignification in acid medium.

Fractionated dissolution of the remaining lignin by alkaline extraction gave fractions with small variation in N-contents (2.9–3.4%) and hydrophilicity. The last fraction exhibited the highest sorption of water vapor. The delignification was related to the decrease in molecular size during the pretreatment and during the subsequent alkaline treatments.     

Effect of Alkaline Hemicellulose Extraction on Kraft Pulp Fibers from Eucalyptus Grandis

Abstract

The alkaline extraction of hemicelluloses from hardwoods prior to pulping, for further conversion to value-added products, seems to be a promising pathway for paper mills to increase profit and improve sustainability. However, the amount of hemicellulose extracted will be limited by the requirement to maintain pulp quality and pulp yield in comparison to existing pulping processes. The effects of NaOH concentration, temperature, and time on hemicellulose extraction of Eucalyptus grandis were studied using a statistical experimental design. Extracted wood chips were subjected to kraft pulping to evaluate the effect of the extraction on cooking chemicals, pulp quality, and handsheet paper strengths. The selective xylan recovery (12.4% dry mass) from E. grandis combined with low-cooking, active alkali charge, and less cooking time advantaged the xylan extraction and subsequent modified kraft pulping process under the studied conditions. Pulp viscosity, breaking strength, and tensile index of handsheets were slightly improved.     

Simulation of the Condensate Treatment Process in a Kraft Pulp Mill

A simulation program has been developed and used to study the condensate treatment process in a kraft pulp mill consisting of a stripper, a methanol column and a decanter. The simulations require rigorous models for vapor‐liquid and liquid‐liquid equilibrium calculations. The Wilson equation and the NRTL equation (non random two liquids) have been used for these calculations. New data were included in the flowsheeting program Aspen Plus for seven volatile compounds, to perform accurate calculations of both vapor‐liquid and liquid‐liquid equilibria. Simulations were compared with measurements on the industrial condensate treatment process and the results of the simulations were used to improve the process. By changing the position of the decanter in the process, the COD (chemical oxygen demand) content in the stripped condensate was decreased from 700 to 300 mg O₂/l. The effect of various process parameters, such as the vapor fraction after the stripper and the flow rate of secondary steam to both the stripper and the methanol column, on the quality of clean condensate were investigated. The design of the stripper and the methanol column was studied by calculating the optimal feed location for various numbers of trays in the columns. The results showed that the feed location in the methanol column would be more optimal if it were located higher up in the column (above tray 5–7) instead of above tray 10, which was the case in the industrial process investigated.     

杨木APMP与杨木化学浆配抄对纸张性能的影响

研究了典型的国产高得率浆杨木碱性过氧化氢机械浆(APMP)与杨木化学浆配抄对纸张有关性能的影响。结果表明,杨木APMP的比例在50%时,纸张松厚度和不透明度分别增加了39%和9%;同时,纸张平滑度和强度性能有所下降,但由于杨木APMP具有较高的细小纤维含量,因此在一定程度上抵消了其负面影响。