Effects of Mg-based Alkaline Peroxide Bleaching on Physical Properties of Poplar Bleached Chemi-thermomechanical Pulp and Its Influence Mechanism

In this study,Mg O was partially used as an alkali source in the peroxide bleaching process of bleached chemi-thermomechanical pulp(BCTMP).The effects of substitution percentage of Mg O for Na OH on the bulk,optical,and physical properties of bleached pulp,and the main effluent characteristics were analyzed.In addition,the influencing mechanism of Mgbased alkali on the strength properties of the BCTMP was further investigated.Strength properties of the BCTMPs were investigated as a function of charge characteristics,fiber morphology,surface lignin content,relative bonding area,and hydrogen bonds of the BCTMP.The results showed that cationic demand(CD) and chemical oxygen demand(COD_(Cr)) of the bleaching effluent decreased as the substitution percentage of Mg O for Na OH increased; meanwhile,the bulk and optical properties of the BCTMP increased.Nevertheless,the strength properties(tensile,tear,and burst indices) of the bleached pulp decreased as the substitution percentage of Mg O for Na OH increased.The decrease in the fiber charge density and increase in the surface lignin content affected the fiber swelling,resulting in a decline in pulp interfibers bonding strength and further loss of the tensile and burst indices.

Green and Effective Ammonium Carbonate-assisted Process for Drying Hemicellulose Obtained through Alkali Extraction of Bleached Bamboo Kraft Pulp

Hemicellulose has a wide range of applications,including that as an emulsifier for the food industry and raw material for the synthesis of bioethanol/biochemicals and biodegradable films.Hemicellulose is usually present as a spent liquor,such as the prehydrolysis liquor of the prehydrolysis kraft dissolving pulp production process and the alkali extraction liquor of the cold caustic extraction of pulp fibers.Due to its dilute nature,hemicellulose needs to be dried for practical utilization,and this is challenging.In this study,cellulose and hemicellulose in a bleached bamboo kraft pulp were separated using an alkali extraction process.Hemicellulose obtained from the extraction liquor was dried by an ammonium carbonate-assisted drying process.The effects of drying time and drying temperature were determined.Structure of the hemicellulose obtained by the ammonium carbonate-assisted drying process was similar to that of original hemicellulose,as revealed by detailed Fourier transform infrared and X-ray diffraction analyses.The novel drying method was more energy efficient and required a shorter drying time than the conventional freeze drying method,and the excellent solubility in alkaline solutions favored the chemical modification of hemicellulose.The dried hemicellulose can be used as a renewable raw material for the preparation of hydrogels and other substances such as bioethanol/biochemicals and biodegradable films.

THE OXYGEN-ALKALI BLEACHING OF THE STRAW PULP

The influences on the brightness, viscosity and Kappa of the straw pulp under the different oxygen-alkali bleaching conditions have been studied in this paper.

针叶木浆制备莱赛尔级溶解浆工艺探究

实验以针叶木浆为原料,针对标莱赛尔纤维专用溶解浆性能指标,探究了冷碱抽提、纤维素酶处理及两者联合预处理对浆料特性的影响,优选出针叶木浆制备Lyocell级溶解浆的工艺。结果表明,采用先碱处理后纤维素酶处理两步法,可以显著提升浆料的性能,最优条件下所得溶解浆中α-纤维素含量达到97.1%、聚合度为663.2、灰分含量0.03%、铜离子含量1.2mg/kg、白度90.2%ISO。

烧碱法协同乙酸钠制浆及其碱回收实验研究

在传统烧碱法制浆的基础上添加乙酸钠进行制浆,探究不同乙酸钠用量、氢氧化钠用量、蒸煮温度和保温时间对成浆效果的影响,得到了乙酸钠制浆的最佳工艺参数,从而开发了一种得率高、成浆效果良好的新型制浆工艺。研究结果表明,氢氧化钠和乙酸钠用量分别为木片质量的20%和10%时,并在165℃下保温3 h,纸浆得率为51.49%,比传统的烧碱法制浆的纸浆得率(40.12%~43.41%)提高了8.08%~11.37%;将所得纸浆进行抄纸后,其纸张具有良好的力学性能;同时,其蒸煮后所得黑液经过燃烧和石灰碱化处理后,碱回收率较高。这证明了烧碱法协同乙酸钠制浆工艺的可行性,从而促进制浆造纸的技术进步。

化机浆碱回收工艺设备的研发与应用

根据化机浆生产线大型化趋势和环保政策导向,化机浆污水生化处理已不能满足排放要求,需要适用的碱回收工艺设备满足化机浆污水处理需求,汶瑞机械(山东)有限公司研发的碱回收蒸发和苛化工艺设备,历经多个项目实际使用和不断完善,成为经济实用、成熟可靠的化机浆污水处理碱回收系统技术设备。

NaOH-AQ法蒸煮过程中用碱量对剑麻浆纤维力学性能的影响

本研究对烧碱-蒽醌(NaOH-AQ)法蒸煮过程中不同用碱量下的剑麻浆纤维力学性能差异进行了系统分析。同时,对其纤维形态、微纤丝角、结晶度以及木质素含量进行研究,以探究其与单根纤维力学性能的协同效应。结果表明,随着用碱量从12%升至30%,剑麻浆单根纤维的弹性模量由12.60 GPa降至6.99 GPa;柔软度指数由0.54×10^(17)/(N·m^(2))增至3.15×10^(17)/(N·m^(2));细胞壁硬度在用碱量18%时达到最大值449.20 MPa,纸张的零距抗张指数在用碱量15%时达到最大值177 N·m/g。

云杉预水解硫酸盐法制备Lyocell纤维用溶解浆

针对目前国产Lyocell纤维用溶解浆质量不高、来源不稳定等问题,以俄罗斯云杉为原料,采用预水解硫酸盐蒸煮工艺制备了高品质Lyocell纤维用溶解浆粕。考察了预水解、硫酸盐蒸煮、二氧化氯、过氧化氢漂白及酸处理等工艺对溶解浆粕关键技术指标(如α-纤维素含量、聚合度、白度、灰分以及金属离子含量)的影响。试验结果显示,保温时间90 min、温度150℃、固液比1∶4为最佳预水解条件,碱用量24%、硫化度30%、保温时间180 min为最佳蒸煮条件。在最佳预水解和蒸煮条件下制备的浆料经过二氧化氯质量分数1.5%漂白、冷碱质量分数12%抽提、过氧化氢质量分数5%漂白和乙酸质量分数6%处理后,所得浆粕的α-纤维素含量为96%,白度为85%,聚合度为647,灰分为0.06%,铁离子含量为6 mg/kg,铜离子含量为3 mg/kg。偏光显微镜观察显示,该浆料在90℃的N-甲基吗啉-N-氧化物(含水率为13.3%)中30 s即可完全溶解。

Lignin Extraction from Black Liquor and its Application Prospects in Pulp Mills

This paper summarizes the possible application of lignin extraction from black liquor and the development of lignin extraction technology.Lignin extraction from black liquor is an important,economical method to resolve the bottleneck associated with the recovery boiler and achieve the targeted capacity expansion in pulp mills.A few of key issues must be taken into cosideration when lignin extraction technology is adopted on the industrial scale.

Effect of cooking conditions and oxygen-delignification on Bambusa tulda kraft pulping using experimental design and regression models

This study was concerned on the influence of cooking liquor parameters i.e. active alkali （AA） and sulfidity, on the properties of pulp produced from Thai bamboo by means of multivariate analysis. The investigated pulp properties were cooking yield and viscosity. The experiments were performed according to a face centered cube experimental design. Then, multiple linear regression （MLR） of independent and dependent variables were conducted with SPSS software using least square method. In order to optimize process, Pareto-Optimality method was employed. The obtained regression models were characterized by both descriptive and predictive ability （R^2 ≥ 95% and Rcv^2 ≥ 93%） and allowed the kraft pulping process with an acceptable viscosity （ 1110- 1 190 ml/g） and a total yield about 50% at a sulfidity level of 20-30% with 18% AA. Results indicated that high sulfidity at a lower AA could get high viscosity and relatively low kappa number for pulps. Also oxygen delignification was studied in this research.

玉米秸秆中还原糖的预提取及其对制浆性能的影响

本研究通过碱(NaOH)和酸(HCl)预处理以提取玉米秸秆中的还原糖,采用扫描电子显微镜观察玉米秸秆预处理前后的形态变化,探究了预处理前后玉米秸秆的制浆性能及纸张强度性能。结果表明,在150℃,NaOH和HCl用量分别为6%,预处理时间120 min条件下,玉米秸秆的酸、碱抽提的还原糖(Trs)得率分别为34.2%和14.5%。其中,酸预处理玉米秸秆在碱用量为12%蒸煮时,纸浆得率最高,为48.1%。此外,酸和碱预处理后纸张撕裂指数分别降低了18%和13%,抗张指数也呈现下降趋势,分别降低了28%和16%,耐破指数分别降低了60%和41%。因此,预处理过程中半纤维素的损失会导致纸张强度性能降低。

福建某金矿选矿尾渣的无害化处置工艺

为切实推进福建某金矿山的可持续发展,本研究在充分结合上游选矿工艺流程及指标的基础上,对选矿尾渣(炭浸尾浆及堆浸渣)处置进行了详细的实验研究。结果表明:对于炭浸尾浆中的含氰废液,采用碱氯化(漂白粉)法破氰工艺,可有效去除其中氰化物,CN-浓度从250 mg/L下降至0.217 mg/L,去除率达99.90%。实验指标成功应用于生产实践,效果同样显著。开发的选矿尾渣无害化处置工艺,即固体废渣(炭浸废渣和堆浸渣)混排用于生态修复,炭浸废水破氰达标后视生产实际回用或外排,极大地节约了矿区尾矿库库容,减少了排土场的占用。生产实践可为同类型金矿山选矿尾渣的末端处置提供基础依据。

基于DPM模型的碱回收炉竹浆黑液雾化数值模拟研究

为高效回收高固含量竹浆黑液的化学品和热能,改善其雾化性能,本研究采用DPM(discrete phase model)模拟研究碱回收炉中高固含量竹浆黑液的雾化性能。通过建立的碱回收炉三维几何模型,采用Fluent软件对碱回收炉进行冷态流场模拟,研究了黑液黏度、雾化锥角及粒径范围对碱回收炉中黑液雾化效果、颗粒分布、熔融物垫层形成的影响。结果表明,增大黑液黏度对液滴破碎影响显著,而对于分散沉降的影响远不及雾化锥角及初始液滴尺寸;碱回收炉前墙上、下二次风之间区域存在结渣风险。液滴粒径大于0.5 mm时,黑液液滴主要受重力作用下沉至垫层,能有效减少气流的机械携带现象。

竹浆碱回收锅炉烟气污染物排放影响因素探析

根据四台竹浆碱回收锅炉的实际运行情况,分析碱回收锅炉污染物排放的影响因素。

综合法二氧化氯和离子膜法氯碱工厂含氯废气处理工艺

结合大型制浆企业化学品工厂的生产特点,重点研究了一种含氯尾气的处理工艺与改造升级。

碱预浸低温硫酸盐法制备竹浆粕及其抗菌性的研究

为了保留竹子的天然抗菌性,以四川慈竹为原料,利用碱预浸低温硫酸盐法和常规硫酸盐法制备竹浆,对两种工艺条件下的浆料性质进行对比,探讨了碱预浸低温硫酸盐法蒸煮的最佳工艺条件。结果表明,最佳碱预浸条件为:预浸温度120℃,NaOH用量12%,渗透剂用量1.75%,预浸时间30 min;预浸后的蒸煮条件:用碱量(以Na2O计)20%,硫化度18%。碱预浸低温硫酸盐法浆粕中α-纤维素含量能够达到91%以上,且较常规硫酸盐法有更好的抗菌性。

我国的木浆和麦草浆黑液碱回收现状

简述了我国制浆黑液碱回收的现状,全面分析了我国木浆与麦草浆碱回收的不同。以我国木浆、麦草浆黑液典型碱回收为实例,对蒸发、燃烧、苛化系统的能耗进行了计算,并分析了碱回收产生的主要产品和副产品。我国木浆黑液碱回收处在世界领先的水平,麦草浆黑液的碱回收具有中国特色,在回收热能治理污染方面虽然发挥了巨大的作用,但与先进的木浆黑液碱回收相比,还有很大的差距,还需要继续努力,不断提高。

碱处理芦苇浆纳米纤维素制备工艺条件优化

采用质量分数55%硫酸水解碱处理芦苇浆制备纳米纤维素,研究反应时间、反应温度和碱处理时间对纳米纤维素得率及其平均粒径变化的影响。单因素试验最优制备条件为碱处理时间1.0 h,反应温度60℃,反应时间2.0 h,纳米纤维素得率为54.50%,平均粒径为156.9 nm;通过傅里叶红外和X射线衍射分析,结果表明碱处理芦苇浆制备纳米纤维素为纤维素Ⅱ型。在单因素试验基础上进行正交优化试验,对纳米纤维素得率而言,正交优化最佳工艺条件为碱处理时间1.0 h,反应温度60℃,反应时间3.0 h,此条件下纳米纤维素得率最高,为55.64%,平均粒径为166.3 nm。

麦草氧碱两段蒸煮黑液性能的研究

对麦草进行NaOH +AQ/NaOH +O2 两段蒸煮 ,研究了氧碱蒸煮段用碱量、最高温度。

棉短绒制绒毛浆H_2O_2-氧碱蒸煮工艺

介绍了棉短绒制绒毛浆的H2O2-氧碱制浆工艺,对比研究了原料预处理及添加Na2CO3对棉绒 制浆得率、纸浆白度及吸水高度的影响。