Straw Pulp Research Articles

Empirical analysis on influencing factors of waste paper recovery rate in China

ABSTRACTThe research calculated the waste paper recovery rate, and analyzed the main factors influencing waste paper recovery rate in China with time series data from 1970 to 2012. The consequent recovery rate and utilization rate of waste paper show that the recovery of paper products has been experiencing a rapid growth in China, but it cannot meet the domestic need. The empirical analysis proves that demand is the main driver to stimulate the increase of waste paper recovery rate in China; the increased average GDP per capita and proportion of waste paper pulp are two other important factors; the increased urbanization rate does not exert significant influence. In the circumstance of insufficient timber supply, the policy of eliminating straw pulp capacities for paper-making indusrty improves the recovery rate of waste paper.

Mixing Bleached White Poplar and Wheat Straw Chemimechanical Pulps to Improve the Mechanical and Optical Characteristics

The aim of this study was to determine the optimum combination of wheat straw and white poplar (P. alba) chemimechanical pulps (CMPs) for producing newsprint paper. The CMP was prepared separately from the two raw materials. Cooking conditions included 10%, 12%, and 14% chemical charge based on w/w oven dry raw materials, maximum cooking temperatures of 120, 140, and 160 °C, and cooking time of 45 min. Hydrogen peroxide was used for bleaching the selected pulp. The results indicated that screened pulp yields were in the range of 54.3% to 61% and 80.9% to 85.9% for 18 cooking trials of wheat straw and white poplar, respectively. Handsheet brightness reached up to 52.9% and 61.9% for wheat straw and white poplar, respectively. The highest breaking length and burst index were related to CMP produced from 25% white poplar/75% wheat straw pulp blend. The best tear index was obtained using a mixture of 50% white poplar and 50% wheat straw pulp. Averages of breaking length, burst and tear indices ranged between 4.61 and 3.80 km, 2.31 and 2.55 kPa•m2/g, and 7.29 and 11.1 mN•m2/g, respectively. The strength properties of handsheets were higher than those reported for commercial newsprint except the breaking length of 50%/50% blend.

King oyster mushroom production using various sources of agricultural wastes in Iran

King oyster mushroom (Pleurotus eryngii) contains many medicinal and nutritional values, excellent flavors, and a long shelf life. Cultivation of edible mushroom on agricultural and lignocellulosic waste like wheat straw and wood chips gives a high yield and nutritional contains. In present study, the effects of lignocellulosic organic wastes, such as wood chips, wheat and barley straw, sugar beet pulp, sawdust and maize stem residue as basal substrate and wheat and rice bran, soybean powder and their combinations were used as supplements. We analyzed mushroom production gap, mushroom fresh weight, moisture content, dry matter, and protein content of fruit body traits. A factorial experiment was conducted in a completely randomized design with four replications. Supplementation of wheat bran in wood chips increased the mushroom production gap and dry matter content. The highest mushroom fresh weight and moisture content were achieved on barley straw and sugar beet pulp substrate complemented with rice bran, respectively. In addition, protein content ranged from 4.64 % (barley straw + wheat bran and wood chips + soybean powder + rice bran treatments) to 13.66 % (wheat straw + wheat bran + soybean powder treatment). The quality of P. eryngii was significantly affected by substrate ingredients. The type of substrate as well as the type and quantity of supplement appeared to have a substantial effect on prolonging the delayed-release nutrients.

麦わらパルプシートの低密度化特性および表面自由エネルギーの変化

麦わらパルプシートの低密度化特性および表面自由エネルギーの変化

Obtaining of straw pulp in isobutanol medium

Проблематика. Зменшення витрат деревини та викидів шкідливих речовин у довкілля за рахунок екологічно безпечних способів делігніфікації рослинної сировини. Мета дослідження. Визначення впливу технологічних параметрів процесу одержання органосольвентної солом’яної пшеничної целюлози та дії каталізаторів (антрахінону і гідразину) на процес делігніфікації та основні показники якості целюлози, кінетичні показники. Методика реалізації. Варіння органосольвентної солом’яної целюлози з використанням каталізаторів проводили в стальних автоклавах об’ємом 0,25 дм 3 , занурених у гліцеринову баню за температури 140–180 °С упродовж 30–150 хв. Результати дослідження. Отримана органосольвентна солом’яна целюлоза з використанням як каталізатора антрахінону і гідразину характеризуються відповідно такими фізико-механічними показниками: розривна довжина – 7900–6900 м; індекс продавлювання – 4,33–4,52 кН/г; опір згину – 128–600 подвійних перегинів. Встановлено, що використання гідразину порівняно з антрахіноном дає змогу отримати целюлозу з меншим вмістом лігніну, золи та пентозанів. Визначено, що процес делігніфікації в системі ізобутанол–КОН–вода–каталізатор описується кінетичним рівнянням другого порядку. Розраховано кінетичні характеристики (константи швидкості та енергії активації) процесу делігніфікації пшеничної соломи і показники вилучення лігніну із рослинної сировини. Висновки. Одержана органосольвентна солом’яна целюлоза придатна для виготовлення масових видів картонно-паперової продукції, а після проведення процесів вибілювання та облагороджування – для подальшої хімічної переробки на різні похідні целюлози.

Inclusion of fiber in diets for brown-egg laying pullets: Effects on growth performance and digestive tract traits from hatching to 17 weeks of age

We investigated the effects of fiber inclusion in the diet on growth performance and digestive traits in pullets from hatching to 17 wk of age. The control diets of the 3 feeding periods (0 to 5 wk, 5 to 10 wk, and 10 to 17 wk) were based on corn and soybean meal and did not include any additional fiber source. The experimental diets included 2 or 4% of cereal straw or sugar beet pulp (SBP) at the expense (wt:wt) of the control diet. From 0 to 5 wk of age, fiber inclusion did not affect pullet performance. From hatch to 17 wk of age, the inclusion of straw had little effect on pullet performance but the inclusion of 4% SBP reduced (ADG) (P < 0.05) and reduced feed conversion ratio (FCR; P < 0.001). Pullets fed straw had greater ADG (P < 0.05) and better energy conversion ratio (P < 0.01) than pullets fed SBP. An increase in fiber from 2 to 4% reduced FCR (P < 0.05). Body weight uniformity was not affected by diet. Fiber inclusion increased the relative weight (% BW) of the gizzard at 5 wk (P = 0.056) and 10 wk (P < 0.01) of age, but no differences were detected between fiber sources. At same ages, the relative length (cm/kg BW) of the pullets (P = 0.058 and P < 0.01, respectively) and tarsus (P = 0.079 and P < 0.05, respectively) was higher in pullets fed SBP than in pullets fed straw. Fiber inclusion, however, did not affect any of these traits at 17 wk of age. In summary, the inclusion of 2% straw at the expense (wt:wt) of the whole diet did not affect pullet performance at 17 wk of age. An increase in the level of straw from 2 to 4% reduced FCR but did not affect ADG. The inclusion of SBP, however, reduced pullet growth, with effects being more pronounced at the higher level.

Influence of Operating Variables and Model to Minimize the Use of Anthraquinone in the Soda-Anthraquinone Pulping of Barley Straw

Soda-anthraquinone (soda-AQ) pulping of barley straw was used to obtain cellulosic pulps for papermaking purposes. The identified parameters, or variables to be optimized, were operating time, anthraquinone concentration, and PFI refiner revolutions, and the influence of these operating variables on pulp properties was studied. A polynomial model that reproduced the experimental results with errors less than 6% was developed. Operating variables were found (46 min of processing time, 0.4 wt.% of anthraquinone concentration, and 3000 rpm of PFI revolution) that yielded competitive pulp properties (82 °SR beating grade number, 870 mL/g of viscosity, Kappa number of 13, 77 Nm/g of tensile index, and 30% ISO brightness) at reasonable chemical and energy costs. On the other hand, this study highlights the usefulness of this polynomial model as a method to minimize the use of anthraquinone in these pulping processes and to be able to predict what the pulp properties will be. For comparison purposes, new operating conditions were found, and the pulp properties still remain at a very good level for this cereal straw.

Network optimization and performance evaluation of the water-use system in China’s straw pulp and paper industry: a case study

Compared with wood pulp, straw pulp and papermaking, because of lower cost and abundancy of raw material, has become an indispensable approach in paper industry of China. However, its further application is limited by huge water consumption and wastewater discharge. By employing substance flow analysis, this study built up an optimization model and a performance evaluation system of water saving for the water-use network of a straw pulp and paper enterprise, after identifying the problems in present water consumption. Accordingly, an optimization plan was proposed to combine man-made water circulation with natural water circulation system. Additionally, a contrast analysis between the present and optimized water use was conducted. At last, we applied the proposed optimization plan to one of the most important and largest enterprises of straw pulp and paper industry in China as an illustration. Theoretically, water consumption could be reduced by 75.4 % without wastewater discharge after optimization.

Modification in the properties of paper by using cellulase-free xylanase produced from alkalophilic Cellulosimicrobium cellulans CKMX1 in biobleaching of wheat straw pulp.

Alkalophilic Cellulosimicrobium cellulans CKMX1 isolated from mushroom compost is an actinomycete that produces industrially important and environmentally safer thermostable cellulase-free xylanase, which is used in the pulp and paper industry as an alternative to the use of toxic chlorinated compounds. Strain CKMX1 was previously characterized by metabolic fingerprinting, whole-cell fatty acids methyl ester analysis, and 16S rDNA and was found to be C. cellulans CKMX1. Crude enzyme (1027.65 U/g DBP) produced by C. cellulans CKMX1, having pH and temperature optima of 8.0 and 60 °C, respectively, in solid state fermentation of apple pomace, was used in the production of bleached wheat straw pulp. Pretreatment with xylanase at a dose of 5 U/g after pulping decreased pulp kappa points by 1.4 as compared with the control. Prebleaching with a xylanase dose of 5 U/g pulp reduced the chlorine charge by 12.5%, increased the final brightness points by approximately 1.42% ISO, and improved the pulp strength properties. Xylanase could be substituted for alkali extraction in C-Ep-D sequence and used for treating chemically bleached pulp, resulting in bleached pulp with higher strength properties. Modification of bleached pulp with 5 U of enzyme/g increased pulp whiteness and breaking length by 1.03% and 60 m, respectively; decreased tear factor of pulp by 7.29%; increased bulk weight by 3.99%, as compared with the original pulp. Reducing sugars and UV-absorbing lignin-derived compound values were considerably higher in xylanase-treated samples. Cellulosimicrobium cellulans CKMX1 has a potential application in the pulp and paper industries.

Fractionation of epidermal cells from wheat straw pulp by flotation

The wide availability of wheat straw makes it a promising raw material for various fiber products, but its heterogeneity makes it a challenging material to use. In addition to reducing paper properties, some cell types cause processing problems such as silicate deposition and poor dewatering. The aims of this work were to examine the fractionation tendency of wheat straw pulp cells in flotation and to determine the effect of fractionation on paper strength properties. A cell type categorization based on automatic optical fiber analysis was used to assess fractionation. The results showed that epidermal cells can be selectively enriched from unbleached wheat straw pulp by flotation and other short cells had a tendency to become enriched in the overflow fraction. The underflow fraction consisted mostly of fibrous material, as well as vessel elements and long parenchyma cells. Removal of the epidermal cells from pulp will reduce its silicate content and improve the strength properties of the paper.

Impact of Causticizing Calcium Carbonate from Soda Pulping of Wheat Straw on AKD Sizing

The causticizing calcium carbonate (CCC) produced in the causticizing stage of the chemical recovery process in alkaline pulping of wheat straw has a high silicate content and is difficult to convert to calcium oxide in the lime kiln. The CCC can be utilized as a paper filler to avoid costly lime re-burning, but the silicate content of the CCC can have a negative impact on the wet-end chemistry of the papermaking process. In this paper, the effect of the silicate content of the CCC filler on AKD sizing was investigated. CCC fillers of various silicate contents were prepared in the lab by causticizing green liquor from the soda pulping of wheat straw and were added to fiber suspensions at the wet end of the papermaking process. The results show that the impact of the CCC filler on AKD sizing was associated with its silicate content. As the silicate content increased, the specific surface area and negative charge density of the CCC particles markedly increased, resulting in more AKD adsorption onto the CCC particles instead of fibers.

Barley Straw (Hordeum vulgare) as a Supplementary Raw Material for Eucalyptus camaldulensis and Pinus sylvestris Kraft Pulp in the Paper Industry

The present study shows that barley straw (Hordeum vulgare) can be a supplementary raw material of softwoods and hardwoods such as Pinus sylvestris and Eucalyptus camaldulensis, respectively, for the production of cellulose and paper, reducing an agricultural residue that has no added value. Barley straw has a lower content of cellulose at 36.4% than P. sylvestris and E. camaldulensis, but it contains a lower quantity of lignin, 15.9%. After pulping with soda anthraquinone (AQ), high contents of cellulose (56.5 to 67.5%) and holocellulose (>80%) were attained. Paper sheet properties were able to reach, and even improve upon, those of wood species (Pinus and Eucalyptus) pulped with kraft. Better values of total yield (56.5%), Kappa number (8.9), and ISO brightness (36.4%), were attained for paper sheets from barley straw pulp versus E. camaldulensis and P. sylvestris, respectively, and comparable values for viscosity, tensile, and burst index were obtained.

The influence of chloride-based 1-butyl-3-methylimidazolium ionic liquid on the pulping process of wheat straw cooking

The chloride-based 1-butyl-3-methylimidazolium ionic liquid was applied in the wheat straw pulping process, and its related parameters were investigated in this paper. Single factor and orthogonal experimental methods were used to optimize the parameters of pulping process. The results showed that the optimum pulping parameters of ionic liquid for wheat straw cooking were: cooking temperature 100°C, cooking time 60min and the mass ratio of wheat straw to ionic liquid 1:9 at normal atmospheric pressure. Under these conditions, the pulp yield was up to 85%. According to the physical properties of the handsheets prepared at an amplified scale, pulp obtained by ionic liquid cooking had better properties than that from a standard chemical pulping process. Moreover, the ionic liquid solvent can be reused, and the recovery rate was more than 93.16%.

Recovery and characterization of lignin from alkaline straw pulping black liquor: As feedstock for bio‐oil research

ABSTRACTConversion of lignin derived from lignocellulosic biomass to bio‐oil has the promising potential to significantly reduce petroleum dependence. For that purpose, it is necessary to search for a low‐cost lignin source. In this study, lignin sample was separated from straw pulping black liquor by HCl‐precipitation, followed by extraction with a mixture of dioxane and water. The content of lignin in the total black liquor solid reached up to 34.8%, determined by UV spectroscopy, and the yield could account for 74.4% of the total lignin composition. The structure of lignin was investigated by various spectroscopic techniques such as FTIR, 1H‐NMR, XRD, and XPS. The structural analysis revealed that recovered lignin preserved basic lignin structure, but had relatively lower amount of β‐O‐4 linkages. The molecular weights were studied through THF‐eluted GPC showing that separated lignin had the low Mn, which was favorable for the full degradation process during conversion of lignin to bio‐oil. Therefore, a feasible solution for effective utilization of lignin in straw pulping black liquor as feedstock for bio‐oil was proposed in the study. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42057.

Method of Black Liquor Combustion to Remove Silicon from Wheat Straw Pulping

The effects of aluminium sulphate and sodium aluminate on physical and chemical properties of wheat straw pulp black liquor were studied. Results showed that the expansion rate was enhanced by increasing the aluminum salt content; furthermore, the effect of sodium aluminate was better than that of aluminum sulfate. The maximum desilication rate of 92.31% was reached with the addition of 3% sodium aluminate. A rheometer showed that aluminum salt had little impact on the viscosity of thick black liquor, so even at a high temperature it could be conveyed by pumps in paper mill at 110 °C. The effect of aluminium salt on the silicon removal rate during black liquor combustion was also studied. The experimental results showed that both aluminium sulphate and sodium aluminate helped to remove silicon. The desilication rate of sodium aluminate reached 62.33%, higher than that of aluminum sulphate. SEM-EDX illustrated that the aluminum and silicon ions were formed into insoluble precipitates. It was optimal to use 3% sodium aluminate as desilication agent.

Electrocoagulation treatment of black liquor from soda-AQ pulping of wheat straw.

The effect of electrocoagulation treatment was investigated on black liquor from soda-anthraquinone (AQ) pulping of wheat straw. Removal of phenol, chemical oxygen demand (COD), color, total suspended solids (TSS), total dissolved solids (TDS), and total solids (TS) from black liquor was investigated at different current densities by using aluminum electrodes at various electrolysis times (10, 25, 40, 55, and 70 min) and pH levels (3, 5, 7, 9, and 10.5). It was observed that at 16 V, electrolysis time of 55 min and current density of 61.8 mA/cm(2) were sufficient for the removal of the pollutants. Energy consumption was evaluated as an important cost-relation parameter. Results showed that the electrocoagulation treatment reduced color intensity from the high initial value of 18,750 to 220 PCU. This was strongly influenced by the pH level of the wastewater. In addition, it was found that the removal efficiency increased with increasing of current density. The maximum efficiencies for removal were 98.8, 81, 80, 92, 61, and 68 % for color, phenol, COD, TSS, TDS, and TS, respectively. The lowest energy consumption values were obtained at neutral pH after 55 min. Electrocoagulation was found to be an effective, simple, and low-cost technique to treat black liquor.

An Optimum Mixture of Virgin Rice Straw Pulp and Recycled Old Newsprint Pulp and their Antimicrobial Activity

An Optimum Mixture of Virgin Rice Straw Pulp and Recycled Old Newsprint Pulp and their Antimicrobial Activity

Pulps isolated from Miscanthus, oat hulls, and intermediate flax straw with sodium benzoate

To explore the susceptibility of herbaceous plants to delignification with hydrotropic liquors, the pulping of Miscanthus, oat hulls, and intermediate flax straw was performed with a concentrated sodium benzoate solution. The main characteristics of pulp samples derived hydrotropically from Miscanthus, oat hulls, and intermediate flax straw are given. Miscanthus was found to be more susceptible to delignification, with a pulp yield of 45% and lignin content of 7%. For oat hulls, the pulp yield is 31% and lignin content 9%. The cooking of intermediate flax straw affords a pulp in 51% yield but the lignin content is as high as 17%; further studies are needed. The pulps obtained from Miscanthus and oat hulls were confirmed by infrared spectroscopy.

The effects of recycling the pre-extracted liquor on subsequent pre-extraction and soda- AQ pulping of wheat straw

The effects of recycling the pre-extracted liquor on subsequent pre-extraction and soda- AQ pulping of wheat straw

NIRS Characterization of Paper Pulps to Predict Kappa Number

Rice is one of the most abundant food crops in the world and its straw stands as an important source of fibres both from an economic and an environmental point of view. Pulp characterization is of special relevance in works involving alternative raw materials, since pulp properties are closely linked to the quality of the final product. One of the analytical techniques that can be used in pulp characterization is near-infrared spectroscopy (NIRS). The use of NIRS has economic and technical advantages over conventional techniques. This paper aims to discuss the convenience of using NIRS to predict Kappa number in rice straw pulps produced under different conditions. We found that the resulting Kappa number can be acceptably estimated by NIRS, as the errors obtained with that method are similar to those found for other techniques.