慈竹化机浆工艺技术及漂白机理的研究

以慈竹为研究对象,对比研究了5种不同预处理方式及其浸渍效果;分别对预处理后物料进行制浆和漂白操作,比较不同预处理方式对制浆性能的影响;综合考虑技术经济因素,提出了适宜的化学预处理条件;研究了慈竹化机浆的漂白性能,并探讨了碱性过氧化氢制化机浆的漂白机理。分析了慈竹的化学组成、纤维形态等材性特征,结果表明。     

速生材制化学机械浆(CMP)的系列研究——Ⅱ.混合材制漂白化机浆(BCMP)抄造彩印书刊纸的研究

对我国东北林区桦木、杨树、白松混合材制漂白化机浆(BCMP)抄造彩印书刊纸工艺技术研究表明,用碱性亚钠法预浸渍、多段磨浆、一段H_2O_2漂白制得BCMP配以20％针叶漂白化学木浆抄造出符合质量要求的彩印书刊纸。     

碱脲体系对稻草化机浆制浆性能的影响

利用氢氧化钠-硫脲-尿素水溶液处理稻草草片以求改善其化机浆制浆性能,通过单因素试验探究用碱量、浸渍时间和冷冻时间等因素对稻草化机浆制浆性能的影响情况,并利用FT-IR、XRD和SEM等方式表征原料或浆料微观性能的变化情况。结果表明:在用碱量6%、浸渍时间15 min和处理时间60 min、处理温度-5℃的条件下,制得稻草漂白化机浆的性能最佳,和自制稻草BCTMP相比,经氢氧化钠-硫脲-尿素水溶液预处理后制得化机浆的磨浆能耗降低18.6%、细浆得率提高3.8%、白度提高4.4%、抗张指数提高12.8%、耐破指数提高15.7%、松厚度降低2.9%,此外对两种漂白化机浆而言,其官能团结构、结晶区结构、预处理后原料纤维的整体形态均没有明显变化,但经氢氧化钠-硫脲-尿素水溶液预处理后稻草单根纤维表面的破损程度略高。     

蔗渣化机浆制浆工艺实验

研究了以蔗渣为原料 ,用氢氧化钠、碱性亚硫酸钠 ,碱性过氧化氢预处理制化机浆的制浆工艺。并对蔗渣化机浆的物理强度和白度进行了比较     

MgO替代NaOH的杨木PRC-APMP过氧化氢漂白

针对NaOH作为碱源的预处理盘磨化学处理碱性过氧化氢机械浆(PRC-APMP)漂白过程中存在的一些问题,考察了使用MgO在二段化学预浸段和高浓停留段以不同比例替代NaOH进行漂白后对浆张白度、抗张指数以及漂后废液中化学需氧量(CODCr)含量的影响。实验结果表明:在杨木PRC-APMP过氧化氢漂白过程中采用不同比例的MgO替代NaOH,漂后的浆张白度与未替代相比变化不大;抗张指数随替代比例的增加呈下降趋势;二段化学预浸段和高浓停留段废液中CODCr含量随MgO替代NaOH比例的增加呈下降趋势。     

麦草亚铵法氧脱木素浆的短流程漂白

对麦草亚铵法氧脱木素浆进行了P、HP和HQP漂白对比研究,结果表明:在过氧化氢单段漂白时,Na2SiO3的适宜用量为0.4%,在所选过氧化氢用量、NaOH用量、温度和时间的四因素三水平方差分析漂白工艺中,影响纸浆白度的主要因素为NaOH用量;而采用HP和HQP漂白时,漂白浆的白度分别达到78.1%(ISO)和81.9%(ISO),可见采用螯合处理的效果明显。     

废报纸脱墨浆两段漂白工艺研究

研究了废报纸脱墨浆过氧化氢―过氧化氢(PP)、过氧化氢―甲脒亚磺酸(PF)两段漂白工艺。结果表明,废报纸脱墨浆PP漂白中第二段过氧化氢漂白的适宜工艺条件为:浆浓20%,漂白时间2.5 h,温度60℃,乙二胺四乙酸(EDTA)用量0.2%,硫酸镁用量0.05%,硅酸钠用量0.5%,过氧化氢用量4%,氢氧化钠用量0.5%,漂后浆白度71.5%(ISO);PF漂白中第二段甲脒亚磺酸漂白的适宜工艺条件为:漂白温度60℃,漂白时间40 min,浆浓10%,甲脒亚磺酸(FAS)用量1.6%,NaOH用量0.8%,漂后浆白度68%(ISO)。     

非硅过氧化氢稳定剂在桉木TMP浆漂白过程中的应用研究

以桉木热磨机械浆(TMP浆)为研究对象, 探讨了非硅过氧化氢漂白稳定剂G1、G56替代硅酸钠用于桉木TMP浆漂白的可行性, 并对漂白工艺条件进行了优化。结果表明:桉木TMP浆过氧化氢漂白采用稳定剂G1、G56替代硅酸钠是可行的。在浆浓(质量分数)20%、H₂O₂用量9.0%(以绝干浆质量计,下同)条件下优化的漂白工艺条件为:G1用量0.5%, G56用量0.5%, NaOH用量5.85%, 温度90 ℃和时间30 min。在此工艺条件下桉木TMP浆单段过氧化氢漂白后, 浆的白度达到77.47% (ISO), 比原浆白度高38.89个百分点, 比2%硅酸钠用量下漂后浆的白度高1.75个百分点, 与2%硅酸钠和2%DTPA同时用作稳定剂的白度(79.88%(ISO))相当。     

超声波辅助木片常压浸渍及其漂白

采用化学热磨机械浆（CTMP）工艺,以桉木与杨木2种木材为原料,初步研究了超声波辅助木片常压浸渍及其漂白效果。通过监测体系中的残余氢氧化钠的量来探究外部环境体系（温度、时间和用碱量）对超声波辅助木片常压浸渍的影响,结果表明：超声波辅助处理浸渍,桉木为温度75℃,时间30 min,用碱量6%;杨木为温度75℃,时间30 min,用碱量5%,此较优条件下,桉木白度提高2.83%（ISO）,残余过氧化氢质量分数提高了4.4个百分点,碱吸收量达41.5 kg/t,较未经超声波处理后的桉木的碱吸收量提高了5.06%;杨木白度无变化,而残余过氧化氢质量分数提高了2.73个百分点,碱吸收量达38.75 kg/t,较未经超声波处理的杨木碱吸收量提高了6.15%。     

速生材制化学机械浆(CMP)的系列研究——Ⅵ.黑荆树制碱性亚钠化机浆的研究

本文对我国漳州引种的速生相思树—黑荆树(Acacia mearnsii)制碱性亚钠化学机械浆的适应性进行研究和评估,结果表明,采用适宜的化学预处理条件,可以用于制碱性亚钠化机浆,且该浆种一段过氧化氢漂白性能甚优,纸浆可以适用于抄造新闻纸及一般文化用纸。     

木聚糖酶预处理对NaOH-AQ法麦草浆H_2O_2漂白效果的影响

探讨了木聚糖酶预处理对麦草化学浆 H2 O2 漂白可漂性等的影响。结果表明 :与对照浆漂至相近白度 ,木聚糖酶预处理后可节省 H2 O2 用量 4 0 %以上 ,且浆的强度变化不大 ;酶预处理还可以改善 H2 O2 漂后浆的滤水性能 ,提高漂白浆的白度稳定性。     

Bio‐Chemimechanical Pulps from Eucalyptus grandis: Strength Properties,Bleaching, and Brightness Stability

Abstract

Eucalyptus grandis wood chips were treated with the white‐rot fungus Ceriporiopsis subvermispora in a 100‐L bioreactor for 15 days. The treatment was characteristic of a selective biodelignification (7.6±0.2% and 0.3±0.2% of lignin and glucan losses, respectively) with concomitant extractive removal (17.7±0.2%). Biotreated samples and non‐inoculated controls were pre‐cooked in alkaline sulfite and post‐refined in a Jokro mill. The biotreated pulps fibrillated more rapidly and contained lower amounts of rejects than the control. To achieve a freeness of 400 mL, the control pulp required 125 min of beating, whereas the biopulp required only 95 min, a reduction of 24%. Unbleached biopulps had better strength properties than control pulps because higher tensile indexes were obtained for the entire range of tear indexes. Bleaching with 8% hydrogen peroxide increased the brightness of these pulps by 17 points. At low peroxide loads, the brightness increase for biopulps was lower than for the control pulps. Still, the bleachability of sboth pulps was similar for peroxide loads higher than 2%. After a two‐stage H₂O₂‐bleaching sequence, final brightnesses for the control and biopulps were 59.7±0.8% and 60.5±0.4%, respectively. Brightness stability of the bleached control and bio‐CMP pulps to photo and thermal aging were very similar.     

The Effects of Treatment with the White-Rot Fungus Trametes Versicolor and Laccase Enzymes on the Brightness of Douglas-Fir Heartwood Derived Thermomechanical Pulps

Abstract

Douglas-fir is a significant west coast tree species that cannot be used as a furnish in the high yield thermomechanical pulping process (TMP) because of the low brightness caused by the high chromophoric extractive content in its heartwood. Trametes versicolor and laccase enzymes were assessed for their potential to improve the brightness of Douglas-fir heartwood derived TMP. Treatments with Tversicolor were relatively unsuccessful. Although the application of laccase without a mediator decreased the unbleached brightness of heartwood pulps from 40.1 to 34.1 % ISO, after bleaching with H₂O₂, it was found that the laccase treatment increased the bleached brightness from 58 to 61 % ISO. Biological treatments were performed alone and in combination with methanol and alkaline extraction. When pulps were extracted with methanol prior to treatment with laccase and the mediator HBT, the hydrogen peroxide bleached brightness increased from 63 to 64.5 % ISO compared to the non-laccase treated, methanol extracted controls.     

不同蒸煮及磨浆条件对楠竹浆纤维性质的影响

本研究以江西产楠竹为原料用烧碱法、硫酸盐法、添加蒽醌硫酸盐法在温度160℃,碱度16％和硫化度25％下蒸煮,比较研究这三种碱法蒸煮条件下得到的木质素酚化改性潜力及浆料性质。在温和的蒸煮条件下,木质素表现出较大的酚化改性潜力,浆料虽然Kappa值偏高（35～40）,但粗浆得率高（55％-59％）,在立式磨浆机处理条件下与商业漂白浆相比具有更容易控制长度、宽度和长宽比的特点。本研究为如何实现竹材全成分有效利用及如何控制竹浆纤维长短提供可参考的基础数据。     

TCF BLEACHED PULPS FROM MISCANTHUS SINENSIS BY THE IMPREGNATION RAPID STEAM PULPING (IRSP) PROCESS

ABSTRACT

The production of bleached cellulose pulps from elephant grass (Miscanthus sinensis) via a two-stage soda pulping process and a TCF bleaching sequence is evaluated in this work. The impregnation rapid steam pulping process (IRSP) involves impregnating of the lignocellulosic material with the pulping liquor, withdrawing the excess liquor and rapidly steaming the impregnated material at 180–200°C for a short time. In this paper the process variables and their effect on the kappa number, yield and viscosity of the unbleached pulps are discussed. Bleaching by an ozone-based TCF sequence was tested, and the papermaking properties of the bleached pulp were determined. A kappa number of 19 was obtained by impregnating at an alkali charge of 30 + 0.1% anthraquinone carboxylic acid (AQCA) and pulping at 180°C for only 15 min. Kappa was reduced to 16 by extending pulping time to 26 min. The alkali consumption during impregnation and pulping was 10.2 g NaOH/100 g of dry Miscanthus. Screened pulp yield, viscosity and brightness for this pulp were 54.6%, 913 mL/g and 37.3%, respectively. After bleaching, the pulp had an ISO brightness of 87.4% and a viscosity of 700 mL/g. Refining in a PFI mill provided optimal strength properties of the bleached pulp at 4500 revolutions (71°SR): breaking length 7.2 km, tensile index 72 N m/g, and burst index 4.3 kN/g. Tear index was 7.9 mN m²/g at this degree of refining.     

Treatment of Douglas‐Fir Heartwood Thermomechanical Pulp with Laccases: Effect of Treatment Conditions on Peroxide Bleaching

Abstract

Douglas‐fir heartwood thermomechanical pulp was treated with laccase enzymes at 25 and 50°C with and without added oxygen. The treated pulps were bleached with hydrogen peroxide at increasing alkali charges. Laccase treatments without added oxygen increased bleached brightness by 1.5–2.5 pts ISO, and decreased hydrogen peroxide consumption by 15–20%. The enzyme treatments were not enhanced when supplemented with oxygen. When the effectiveness of four different laccase enzymes was compared for the treatment of Douglas‐fir heartwood thermomechanical pulp, there were no significant differences found in the performance among the enzymes. Possible explanations for the observed results are given.     

Alkaline sulfite/anthraquinone pulping of pine wood chips biotreated with Ceriporiopsis subvermispora

Pine wood chips were treated for 30 days with Cemporiopsis subvermispora in 20 dm³ bioreactors. A typical selective biodelignification was observed. The biotreated wood chips and undecayed controls were subjected to modified alkaline sulfite/anthraquinone (ASA) cooking at 170 °C or 175 °C applying varying cooking times ranging from 30 to 270 min. In all cases, the residual lignin content of the pulps prepared from biologically pretreated wood chips was lower than that of the control pulp. With increasing cooking time, however, the differences in kappa number became smaller. Wood chips cooked for a short time required mechanical refining for fiber liberation. A disk‐refining step resulted in pulps with low reject content (0.4%) and high screened yield (56–60%). In this case, the use of biotreated wood chips provided pulps with significantly lower kappa numbers than for the control pulp (71 and 83, respectively). The pulp from biologically pretreated wood fibrillated rapidly, reaching 20° SR in only 38 min beating time in a Jokro mill, while the control pulp required 56 min to reach the same beating degree. Although easier to beat, the biopretreated pulps showed tensile and burst indices similar to those of the control samples. However, their tear indices were always lower. Easier delignification after wood biotreatment was not observed for the reactions performed at long cooking times. Oxygen delignification of biotreated and conventional ASA pulps with low kappa numbers reduced kappa number and improved brightness considerably with the biotreated pulps being favored by a better preservation of viscosity. Copyright © 2004 Society of Chemical Industry     

Totally chlorine‐free bleaching of Acetosolv pulps: a clean approach to dissolving pulp manufacture

Eucalyptus globulus wood samples were delignified in media containing concentrated acetic acid, water and hydrochloric acid (Acetosolv process) under optimized conditions, and the pulps were subjected to totally chlorine‐free (TCF) bleaching. Alkaline extractions, oxygen delignification, ozone treatment, enzymatic xylan removal and hydrogen peroxide oxidation in alkaline media were investigated as individual steps in selected bleaching sequences. Under the best conditions, fully bleached pulps with favourable characteristics for dissolving pulp manufacture were obtained. © 2001 Society of Chemical Industry     

Mechanistic Differences Between Kraft and Soda/AQ Pulping. Part 1: Results from Wood Chips and Pulps

Abstract

Soda pulping catalyzed by anthraquinone (AQ) or 2-methylanthraquinone (MAQ) can produce hardwood chemical pulps similar to kraft pulps in all respect but for bleachability. Results accumulated in our laboratory suggest that the residual lignin in pulps from anthraquinone catalyzed processes is less reactive toward bleaching chemicals than that in kraft pulps. Analyses of pulps by periodate and permanganate oxidations suggest that the residual lignin from the non-sulfur processes contained more condensed structures than kraft residual lignin. The low reactivity of these structures is believed to be responsible for the lower brightness of bleached soda-AQ (SAQ) pulps. Pulping and bleaching trials with hardwood chips demonstrated that shortening of the cooking time and/or increasing the alkalinity is one strategy for improving bleachability of SAQ pulps. When sugar maple (Acer saccharum) chips were SAQ cooked for 1.0 and 2.0 h at 165°C, the higher kappa number pulp produced after 1.0 h of cooking bleached to a significantly higher brightness with a small increase in the chlorine dioxide application.     

The Use of Ozone or Oxygen in The First Bleaching Stage

An ODED or a ZEDED sequence bleached kraft hardwood and softwood pulps to 87 — 89‰ ISO brightness. The bleached yields were similar for a given pulp, whether oxygen or ozone was used in the first stage. The strength properties of the fully bleached pulps were essentially the same as those of the unbleached pulps. The COD and colour values of the effluents after ozone delignification and subsequent extraction were 25‰ and 60‰ lower, respectively, than those of the effluents after an oxygen treatment.