Cleaner Production of Wheat Straw Pulp HUANG

A pulping method using NH4OH with less amount of KOH as cooking liquor on wheat straw was developed. KOH could reduce consumption of NH3 and cooking time for its strong alkalinity. The effects of various pulping conditions such as composition of cooking liquor, liquid-to-solid ratio, maximum temperature, cooking time to the maximum temperature and cooking time at the maximum temperature were studied. Experimental results indicated that the rate of delignification was 85.12% and the pulp yield was 49.65% under suitable pulping conditions. It looks promising to use black liquor containing nitrogen, phosphorus, potassium and organic substance as fertilizer resources for agricultural production. A new pattern of ecological cycling may be set up between paper industry and farming.

Pulping of Wheat Straw with Caustic Potash-Ammonia Aqueous Solutions and Its Kinetics

A pulping technology of wheat straw with aqueous ammonia and diluent caustic potash was investigated.Because its strong alkalinity, the addition of caustic potash not only reduced the quantity of NH3 consumed and cooking time, but also enriched the black liquor with nutrients such as potassium and nitrogen, which could be used as fertilizer for agriculture. Various pulping conditions including composition of cooking liquor, liquor-to-solid ratio,maximum cooking temperature, time to reach the maximum temperature and time at the maximum temperature were studied systematically to determine the suitable pulping conditions. Results of the cooking course showed that there were three distinct delignification phases, namely, the bulk delignification phase from the beginning of cooking to 100 ℃, the supplementary delignification phase from 100 ℃ to 155 ℃ for 45min and the third delignification phase till the end of cooking. The rate of delignification was found to be first order with respect to residual lignin and 0.34 order with respect to [OH-]. The activation energy of the delignification reaction was 29.75 kJ·mol-1 and the rate equation of delignification was also obtained.

Sulfite-Formaldehyde Pulping and Oxygen Delignification of Wheat Straw

In this study,wheat straw pulp was prepared by sulfiteformaldehyde(SF) pulping combined with oxygen delignification to develop a sustainable methodology for chemical pulping of straw materials.The bleachability of oxygen-delignified SF pulp was also evaluated by hypochlorite bleaching.The results indicated that the Na_2SO_3 charge played an important role in lignin removal during SF pulping as well as oxygen delignification.The efficiency of oxygen delignification of wheat straw SF pulp was markedly high.After the oxygenation stage,the Kappa number decreased by over 50%(the original Kappa number of SF pulp was lower than 30) when the Na OH charge was in the range of 3%~5%.The optimal conditions for preparing bleached pulp via combined SF pulping and oxygen delignification involved the use of 12% of Na_2SO_3 and 3% of Na OH,respectively.Pulp with relatively high brightness,a low Kappa number,as well as an acceptable viscosity could be obtained when oxygen-delignified SF pulp was bleached with hypochlorite under a low active chlorine dosage.

Pulping of Wheat Straw with Caustic Potash-Ammonia Aqueous Solutions and Its Kinetics

A pulping technology of wheat straw with aqueous ammonia and diluent caustic potash was investigated. Because its strong alkalinity, the addition of caustic potash not only reduced the quantity of NH3 consumed and cooking time, but also enriched the black liquor with nutrients such as potassium and nitrogen, which could be used as fertilizer for agriculture. Various pulping conditions including composition of cooking liquor, liquor-to-solid ratio, maximum cooking temperature, time to reach the maximum temperature and time at the maximum temperature were studied systematically to determine the suitable pulping conditions. Results of the cooking course showed that there were three distinct delignification phases, namely, the bulk delignification phase from the beginning of cook- ing to 100℃, the supplementary delignification phase from 100℃ to 155℃ for 45min and the third delignification phase till the end of cooking. The rate of delignification was found to be first order with respect to residual lignin and 0.34 order with respect to [OH - ]. The activation energy of the delignification reaction was 29.75kJ·mol-1 and the rate equation of delignification was also obtained.

BIOPULPING OF WHEAT STRAW WITH PHANEROCHAETE CHRYSOSPORIUM

Wheat straw was cut into a certain size range and treated with a strain of the white rot fungus Phanerochatete Chrysosporium for 5 days before subjected to a chemi-mechanical treatment. Chemical analyses revealed the effects of the white rot fungus on the wheat straw components. SEM was applied to observe the changes in fiber micromorphological structures. CODcr of the effluent from the sulfonation treatment of wheat straw was also discussed. Handsheets made from the treated and untreated wheat straw exhibited different optical and physical properties after chemi-mechanical pulping.

CHARACTERISTICS OF BENTONITE AND ITS SYNERGISTIC RETENTION EFFECT WITH CPAM ON WHEAT STRAW PULP

The various properties of bentonite samples with different sources and their synergistic retention effect with CPAM on wheat straw pulps were investigated. The investigated properties of bentonite included adsorptive capacity based on methylene blue, cation-exchange capacity, swelling volume, colloidal volume, particle size and charge properties. The results show that particle size is the most important properties of bentonite for its synergistic retention effect with CPAM. Using Wyoming type sodium bentonite without drying after modification can obtain the excellent furnishes retention.

XYLANASE PREBLEACHING ON NaOH-AQ WHEAT STRAW PULP

Before calcium hypochlorite bleaching (H) and chlorination,alkaline extraction, calcium hypochlorite three-stage-bleaching (CEH),we used a kind of hemicellulase, xylanase, to treat wheat straw pulp from Gaoyou Papermill. Xylanase pretreatment contained tow stages, the first stage was xylanase treatment, which was followed by alkaline extraction, the second stage. The xylanase could act on partial lignin and carbohydrate, chiefly xylan. The following alkaline extraction could dissolve something that could not be removed during the first stage. The result of pretreatment was to facilitate penetration of bleaching chemicals, to reduce effective chlorine consumption and to lower pollution loading of bleaching effluent. In the case of these two bleaching processes, the enzymatic pretreatment substantially enhanced the optical properties of the pulps. To calcium hypochlorite bleaching, strength properties of pulps were improved.

STUDY OF COORDINATED PRETREATMENT OF XYLANASE AND LACCASE ON SODA-AQ WHEAT STRAW PULP BEFORE CEH BLEACHING

Coordinated pretreatment of xylanase and laccase on Soda-AQ wheat straw pulp before CEH bleaching was studied. Results show: Pretreatment of xylanase and laccase has better effect than of sole xylanase and sole laccase; Coordination can increase pulp brightness and bleachability, improve pulp filterability of water, lighten degree of effluent pollution in bleaching workshop, and develop overall strength properties of bleached pulp.

Mono Ethanol Amine (MEA) Pulping of Wheat Straw: An Environmentally Friendly Suggestion for the Fluff Pulp Production

This research aimed to investigate the effect of pulping conditions and refining intensities of wheat straw to be recommended for fluff pulp production.For this purpose,mono ethanol amine(MEA)was selected as a de-lignification agent at three levels of 50:50,25:75,and 15:85(MEA/water,W/V%),and soda-AQ 14 W/V%was used as a reference pulping.To investigate the optimal refining intensity,the obtained pulp was passed through a single disk laboratory refiner from 0 to 6 times and in two different consistencies(1.5 and 2.5 W/V%).Total yield,kappa number,ash content,and the Schopper-Riegler(SR°)freeness of the prepared pulps were investigated.Finally,hand sheets with a targeted basic weight of 70 g/m^(2) were made according to the related standards.The hand sheets were characterized using Fourier transform infrared(FTIR)spectroscopy and a field emission scanning electron microscope(FE-SEM).Sheet density,brightness,and mechanical properties such as burst,tensile,and tear indices were also investigated.The FE-SEM photographs showed that the texture of the hand sheet became denser as the refining intensity increased.External fibrillation on the surface of the fibers was also observed,especially on those refined with 2.5%consistency.The results of the chemical composition of wheat straw indicated that wheat straw containing a high percentage of holocellulose is an excellent candidate for the production of fluff pulp.The total yield and kappa number of MEA pulps increased with the decrease in MEA concentration.FTIR results indicated the presence of a peak related to amino groups in the pulp related to MEA pulp.The results also indicated that the mechanical properties of the papers,except for the tear index,were enhanced as the intensity of refining and the pulp consistency during refining increased.

麦草浆中木质素含量对防油剂作用效果的影响

在含氟防油剂经济用量范围内,针对麦草高得率浆抄造纸张防油效果不理想的问题,本研究对麦草高得率浆进行氧脱木质素处理,得到一系列不同卡伯值的麦草浆,探讨了麦草浆中木质素含量对防油剂作用效果的影响。结果表明,麦草浆中木质素含量对含氟防油剂的作用效果有明显影响,在防油剂质量分数1%(相对于绝干浆)的条件下,当麦草浆卡伯值降至<50.0时,麦草浆抄造纸张具有初步防油效果;当麦草浆卡伯值为30.0~50.0时,随着卡伯值降低,麦草浆抄造纸张的防油等级逐渐上升;当麦草浆卡伯值降至<30.0时,麦草浆抄造纸张防油等级达到最高等级(7级)。利用Owens-Wendt-Rabel-Kaelble (OWRK)法分析纸张的表面自由能,随着麦草浆中木质素的脱除,纸张的表面自由能不断降低,而极性比率不断升高,表明木质素的脱除有利于提高纸张防油效果。麦草浆中木质素含量也会影响防油剂用量,在一定防油等级要求下,麦草浆的卡伯值越低,所需防油剂用量越少。

基于制浆废液和麦草废渣的生物质颗粒燃料预测模型的建立及分析

以麦草制浆备料工段中产生的麦草废渣和制浆过程产生的制浆废液为原料,通过混合压缩成型工艺制备麦草废渣颗粒燃料,以期提高制浆造纸工业废弃物的利用价值。为探究制浆废液对生物质颗粒燃料成型的影响机制,参照麦草废渣组分,将粉末状商业纯纤维素和半纤维素在质量比10.17∶7.62下与制浆废液混合,制备生物质颗粒燃料模型,并通过曲线拟合建立生物质颗粒燃料预测模型,探究制浆废液中固形物含量对颗粒燃料成型性能及其物理性能的影响机制。结果表明:制浆废液可以提高燃料颗粒间的黏结力,有利于颗粒燃料成型,改善了麦草废渣颗粒燃料的物理性能。当制浆废液固形物含量为10.28%时,麦草废渣颗粒燃料显示出较好的物理性能,其抗渗水性为84.90%,压缩应力为1.45 MPa。生物质颗粒燃料预测模型对麦草废渣颗粒燃料物理性能的预测结果误差小于5%,显示出较高的预测精度。研究结果可为生物质颗粒燃料的制备技术提供理论参考,同时为制浆造纸工业废弃物的综合利用提供新思路。

生物化学机械法制浆过程麦草废渣基棒状颗粒燃料的性能分析

为提高农业废弃物麦草全组分资源化利用效率,本研究将生物化学机械法制浆过程产生的麦草废渣和制浆废液进行混合,利用液压成形技术制备了麦草废渣基棒状颗粒燃料(简称颗粒燃料),探讨了麦渣粒径和废液添加量对颗粒燃料形貌、稳定性、物理性能和燃烧性能的影响。结果表明,颗粒燃料制备的较优工艺条件为:麦渣粒径范围[0.22,0.90)mm,制浆废液添加量36.31%。该条件下制备的颗粒燃料具有较好的稳定性、物理性能和燃烧性能,其松弛密度为1.50 g/cm^(3),抗跌碎性为99.94%,抗渗水性时间为105 min,横向抗压强度为75.1 MPa,径向抗压强度为1.53 MPa,热值为11 715 J/g,燃烧时间可达99 s。

An—76真菌木聚糖酶漂白NaOH一AQ麦草浆的研究

探讨了用Ａｎ—７６真菌木聚糖酶漂白ＮａＯＨ—ＡＱ麦草浆。结果表明，经酶处理后纸浆白度和聚合度提高，ＫＭｎＯ４值降低。酶处理浆的可漂性增加，尤其对过氧化氢漂白影响较大，白度提高３％～４％ＩＳＯ。酶处理浆的强度提高。

木聚糖酶在麦草浆漂白中的应用

对于单段次氨酸盐漂白，木聚糖酶处理（X）可明显改善麦草浆的漂白性能，纸浆白度提高约5％ISO或在相同的白度下减少用氯量28％左右，但与木浆相比处理麦草浆的酶用量较高（50IU／g浆）。采用XCH、CXH、CHX和CH／X漂序纸浆白度可达80％ISO以上，采用XCEH、CEHX或CEH／X漂序纸浆白度接近85％ISO，纸浆强度均有不同程序的提高。

热水和木聚糖酶预处理制备麦草碱法化机浆的研究

对热水和木聚糖酶预处理的麦草碱法化学机械制浆过程中热水和木聚糖酶预处理的效果进行了研究。结果表明 ,在适宜条件下 ,采用热水和木聚糖酶预处理原料可以有效改善麦草碱法化机浆的抗张指数和撕裂度、降低碱的消耗 ,虽然成浆的白度稍有降低 ,但可漂性增加 ,漂白浆白度增加。热水预处理适宜的温度是 90℃ ,酶预处理段较佳的木聚糖酶用量和处理时间分别为 1 5IU/g和 1 2 0min。

内切木聚糖酶与木糖苷酶预处理对麦草浆漂白性能的影响

研究了内切木聚糖酶与木糖苷酶预处理对麦草浆漂白性能的影响。结果表明,无论是内切木聚糖酶还是木糖苷酶预处理漂白浆的白度均比对照浆高,分别高出对照浆的2.5和1.9个百分点,同时漂白浆的强度也好于对照浆的强度。内切木聚糖酶和木糖苷酶混合预处理漂白浆的白度分别比内切木聚糖酶和木糖苷酶高出0.9和1.5个百分点,这表明内切木聚糖酶和木糖苷酶在纸浆预处理过程中具有协同作用。通过电镜观察发现经内切木聚糖酶和木糖苷酶预处理后纸浆的表面和横断面有许多孔隙,其中经内切木聚糖酶预处理后纸浆的孔隙比木糖苷酶要多而且大。通过X 射线衍射分析发现内切木聚糖酶和木糖苷酶均不能破坏纸浆的结晶度。

醌类助剂在碱法蒸煮中的催化效果

介绍 5 种醌类蒸煮助剂在麦草烧碱法蒸煮和不同硫化度（0％，15％，23％）的马尾松硫酸盐法蒸煮中，对纸浆硬度、筛渣率、纸浆得率和黑液粘度等方面催化效果的对比实验结果。结果表明，醌类蒸煮助剂更适用于无硫化钠存在的烧碱法蒸煮。

木聚糖酶的制备及其在麦草浆漂白中的应用

由黑曲霉菌株制备出酸性和偏碱性的木聚糖酶,研究了酶的基本特性,优化了酶的预处理条件,并进行了麦草浆酶预处理-漂白的实验室实验和生产试验。结果表明:当漂白用氯量为5%时,酶处理浆比对照浆提高白度4.5%ISO,在达到相同的纸浆白度时,酶处理浆可节省用氯量28%。

麦草的酶法化学制浆(Ⅰ)不同种类酶液处理对麦草化学制浆性能的影响

对 5种不同种类的酶液 (包括纤维素酶和半纤维素酶 )预处理对麦草化学制浆性能的影响进行了研究。酶液分别来自于As pergillusnigerAn 76、BacilluspumilusA 30、PencilliumdecumbensA 1 0、AspergillusL2 2和Bacillussp Y1 0 6等 5种菌株的发酵液。实验结果表明 ,与常规烧碱法制浆相比 ,在蒸煮前用适宜的酶液对麦草进行预处理 ,可以改善麦草的化学制浆性能 ,获得具有较低卡伯值和较低筛渣率的纸浆。但粗酶液的性质对制浆性能有较大的影响 ,其中具有较高木聚糖酶活与纤维素酶活比值的酶液预处理的效果较佳 (如An 76酶液 ) ,它可在保持纸浆得率的基础上降低纸浆的卡伯值 (降低 2 0 43 % )和筛渣率 (从 1 39%降低到 0 53 % ) ,同时降低蒸煮时有效碱的消耗 ,因而可在获得相同纸浆硬度的前提下降低蒸煮用碱量。而具有较高纤维素酶活的粗酶液预处理 ,在改善麦草制浆性能的同时 ,也会导致纸浆得率的降低和蒸煮时有效碱的消耗增加。

四乙酰乙二胺对麦草浆 H_2O_2 漂白的活化作用

对四乙酰乙二胺（TAED）活化的麦草 Soda-AQ 浆过氧化氢漂白中的几个过程变量（TAED 与 H2O2 的摩尔比、温度、时间、NaOH 用量、过氧化氢用量）进行了研究。结果表明，TAED 对 H2O2 漂白具有显著的活化作用，TAED 与 H2O2 摩尔比 0．5、温度 70℃、漂白时间 30min、NaOH 用量 2％、过氧化氢 3％（均对绝干浆）为较佳的漂白工艺条件。在此条件下漂白，纸浆的白度增值可达 22．0％ ISO，与单纯的 H2O2漂白相比，白度提高了 14．0％ ISO。