Pretreatment Optimization of Poplar Green Liquor Pretreatment-Kraft Pulping

2013 ◽  
Vol 781-784 ◽  
pp. 2654-2657
Author(s):  
Xiao Hong Chen ◽  
Guang Wei Sun ◽  
Jing Hui Zhou ◽  
Ying Han
Keyword(s):  
Process Parameters ◽  
Kraft Pulping ◽  
Holding Time ◽  
Green Liquor ◽  
Liquor Ratio ◽  
Pretreatment Temperature ◽  
Pretreatment Conditions

Green liquor has lower hydroxide concentration and higher sulfidity, which makes it a better choice for modified alkali cooking. This paper studied process parameters of pretreatment stage on pulping properties of poplar green liquor pretreatment-Kraft pulping process. Conditional experiments with green liquor charge of 0.50L/kg, 0.75L/kg, 1.00L/kg and 1.25L/kg, maximum pretreatment temperature of 95°C, 105°C, 115°C and 135°C, and holding time of 30min, 60min and 90min, were carried out. The results shows that optimal pretreatment conditions are as follows: green liquor charge, 1.00L/kg; maximum pretreatment temperature, 115°C; holding time, 60min; and wood to liquor ratio, 1:4.

Reed Soda Pulping Modified by Green Liquor Pretreatment

2013 ◽  
Vol 781-784 ◽  
pp. 2628-2631
Author(s):  
Yi Jia Sun ◽  
Hai Ming Li ◽  
Jing Hui Zhou ◽  
Guang Wei Sun ◽  
Zhang Hong Xie
Keyword(s):  
Kappa Number ◽  
Holding Time ◽  
Practical Significance ◽  
Maximum Temperature ◽  
Green Liquor ◽  
Liquor Ratio ◽  
Soda Pulping ◽  
Pretreatment Conditions ◽  
Heating Up

The soda pulping modified by green liquor pretreatment was adopted to explore optimal green liquor pretreatment conditions. Results shows that optimum pretreatment conditions are as follows: max temperature, 130°C; holding time, 90min; wood to liquor ratio, 1:4; and green liquor charge, 0.9L/kg. Pretreated reed was pulped under following conditions: heating-up time, 60min; maximum temperature, 160°C; holding time, 60min; NaOH charge, 20% (pretreatment alkali included). Results shows that this process produces pulp with screened yield of 49.05%, Kappa number of 14.6, and viscosity of 1274mL/g. Compared with the results of industrial simulation pulping (21% NaOH), screened yield increases by 2.14%, Kappa number decreases by 5.6 and viscosity rises by 556 mL/g. Therefore, green liquor pretreatment before soda pulping improves pulp performance and yield. Meanwhile the pretreatment utilizes material effectively, thus has practical significance to decrease alkaline consumption and pulping cost.

Pentosan Extraction from Poplar Treated by Green Liquid

2013 ◽  
Vol 724-725 ◽  
pp. 399-404
Author(s):  
Jun Ying Zhang ◽  
Jing Hui Zhou ◽  
Hai Ming Li ◽  
Ying Han ◽  
Jun Feng Shi
Keyword(s):  
Kraft Pulping ◽  
Kappa Number ◽  
Raw Material ◽  
Green Liquor ◽  
The Third ◽  
Yield Level ◽  
Lower Viscosity ◽  
Pretreatment Conditions ◽  
Material Temperature ◽  
Process Liquor

Green liquor, a process liquor of alkali recovery in pulp and papermaking industry, pretreatment used in poplar kraft pulping process and the influences of pretreatment conditions on pentosan extraction have been studied. The results show that the influence of green liquor dosage on pentosan extraction is the most remarkable, with temperature taking the second place and time the third. Under the conditions of liquor ratio 1:4, green liquor dosage 1.5 L/kg (based on oven dried material), temperature 100 °C, time 90 min, higher pentosan extraction ratio of 13.81% (based on the pentosan content of raw material) is achieved. The wood was pulped under normal KP conditions after pretreated by the optimal pentosan extraction conditions. Comparing two kinds of pulp with and without pretreatment at similar stock yield level, the results show that the former has a little lower viscosity, significantly decreased Kappa number and excellent paper physical properties.

Fate of phosphorus in the recovery cycle of the kraft pulping process

TAPPI Journal ◽  
2020 ◽  
Vol 19 (3) ◽  
pp. 139-148
Author(s):  
MARYAM SADEGH MOUSAVI ◽  
NIKOLAI DEMARTINI
Keyword(s):  
Kraft Pulp ◽  
Pulp Mill ◽  
Field Studies ◽  
Kraft Pulping ◽  
Pulp Mills ◽  
Recovery Cycle ◽  
Green Liquor ◽  
Green Liquor Dregs ◽  
Kraft Pulp Mills ◽  
Negative Effect

The accumulation of nonprocess elements in the recovery cycle is a common problem for kraft pulp mills trying to reduce their water closure or to utilize biofuels in their lime kiln. Nonprocess elements such as magne-sium (Mg), manganese (Mn), silicon (Si), aluminum (Al), and phosphorus (P) enter the recovery cycle via wood, make-up chemicals, lime rock, biofuels, and process water. The main purge point for these elements is green liquor dregs and lime mud. If not purged, these elements can cause operational problems for the mill. Phosphorus reacts with calcium oxide (CaO) in the lime during slaking; as a result, part of the lime is unavailable for slaking reactions. The first part of this project, through laboratory work, identified rhenanite (NaCa(PO4)) as the form of P in the lime cycle and showed the negative effect of P on the availability of the lime. The second part of this project involved field studies and performing a mass balance for P at a Canadian kraft pulp mill.

scholarly journals Novel Kinetic Models of Xylan Dissolution and Degradation during Ethanol Based Auto-Catalyzed Organosolv Pretreatment of Bamboo

Polymers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 1149 ◽  
Author(s):  
Jing Liu ◽  
Zhenggang Gong ◽  
Guangxu Yang ◽  
Lihui Chen ◽  
Liulian Huang ◽  
...  
Keyword(s):  
Kinetic Models ◽  
Degradation Products ◽  
Practical Significance ◽  
Order Kinetic ◽  
Organosolv Pretreatment ◽  
Dependent Parameter ◽  
Pretreatment Temperature ◽  
Pretreatment Conditions ◽  
Main Components ◽  
The Relationship

Due to the invalidity of traditional models, pretreatment conditions dependent parameter of susceptible dissolution degree of xylan (dX) was introduced into the kinetic models. After the introduction of dX, the dissolution of xylan, and the formation of xylo-oligosaccharides and xylose during ethanol based auto-catalyzed organosolv (EACO) pretreatments of bamboo were well predicted by the pseudo first-order kinetic models (R2 > 97%). The parameter of dX was verified to be a variable dependent of EACO pretreatment conditions (such as solvent content in pretreatment liquor and pretreatment temperature). Based on the established kinetic models of xylan dissolution, the dissolution of glucan and the formation of degradation products (furfural and acetic acid) could also be empirically modeled (R2 > 97%). In addition, the relationship between xylan and lignin removal can provide guidance for alleviating the depositions of lignin or pseudo-lignin. The parameter of dX derived novel kinetic models can not only be used to reveal the multi-step reaction mechanisms of xylan, but also control the final removal of main components in bamboo during EACO pretreatments, indicating scientific and practical significance for governing the biorefinery of woody biomass.

Effect of isothermal process parameters on semi-solid microstructure of chip-based Al–Cu–Mn–Ti alloy prepared by SIMA method

2020 ◽  
Vol 34 (33) ◽  
pp. 2050385
Author(s):  
Ye Wang ◽  
Maoliang Hu ◽  
Hongyu Xu ◽  
Zesheng Ji ◽  
Xuefeng Wen ◽  
...  
Keyword(s):  
Process Parameters ◽  
Ostwald Ripening ◽  
Isothermal Holding ◽  
Treatment Temperature ◽  
Holding Time ◽  
Isothermal Treatment ◽  
Isothermal Process ◽  
Semi Solid ◽  
Average Size ◽  
Relationship Of

A typical Al–Cu–Mn–Ti aluminum alloy chip was adopted to prepare semi-solid billets by a Strain-Induced Melt Activation (SIMA) method, and the effects of isothermal process parameters on the semi-solid microstructure evolution of the alloy were investigated in this work. The result showed that semi-solid billets with highly spheroidal and homogeneous fine grains could be prepared from chips by the SIMA method. With the increase of isothermal temperature, the finer and near-spherical grains are obtained, the grains coarsen and became ellipse at 903 K because of the coarsening mechanisms of coalescence and Ostwald ripening. The relationship of isothermal holding time and grains size followed the LSW theory well, and more spherical microstructure can be brought by prolonging the holding time until 3000 s. Thus, the optimal isothermal treatment temperature is 893 K and holding time is 3000 s, the corresponding average size and roundness of grains are 137 [Formula: see text]m and 1.108, respectively.

scholarly journals A Comprehensive Approach of Eucalyptus globulus Acid Sulfite Pretreatment for Enzymatic Hydrolysis

2020 ◽  
Vol 10 (11) ◽  
pp. 3764
Author(s):  
Vera D. Costa ◽  
Ana Costa ◽  
Maria Amaral ◽  
Rogério S. Simões
Keyword(s):  
Sulfuric Acid ◽  
Enzymatic Hydrolysis ◽  
Eucalyptus Globulus ◽  
High Performance ◽  
Sodium Bisulfite ◽  
Hydrolysis Rate ◽  
Hemicellulose Removal ◽  
Pretreatment Temperature ◽  
Pretreatment Conditions ◽  
Very High

The effect of different acid sulfite pretreatment conditions on released components in the hydrolysates and the pretreated solid residues’ response to enzymatic hydrolysis for Eucalyptus globulus chips was investigated. Sodium bisulfite (0–15%), and sulfuric acid (0–5%) were used to pretreat chips at 170 °C and 190 °C, for as long as 30 min. The hydrolysates were analyzed through high-performance liquid chromatography (HPLC) and spectrophotometry. Overall porosity and pores larger than 2.65 nm (size of a typical cellulase) on the solid residues were estimated using glucose and two dextrans with different hydrodynamic radii as probes. The external specific surface area was analyzed by dynamic light scattering. The solid residues underwent enzymatic hydrolysis with an enzymatic cocktail. Very high (84–95%) carbohydrate conversion was achieved for either an extensively delignified biomass or a biomass with very high content of sulfonated residual lignin (23.4%), since internal porosity enables enzymes accessibility. At least 5% sodium bisulfite and 1% sulfuric acid was required to attain a carbohydrate release above 90% in the enzymatic hydrolysis. Results suggest that the presence of sulfonated lignin does not impair the enzymatic hydrolysis rate and extent. The increase of pretreatment temperature had a positive effect mainly on the initial rate of carbohydrates release in the enzymatic hydrolysis. The increase of the wood material dimensions from pins to conventional chips significantly decreased the hemicellulose removal in acid sulfite pretreatment but had a small effect on the enzymatic yield.

Study on Two-Step Aging Technology of 6082 Aluminum Bumper

2018 ◽  
Vol 764 ◽  
pp. 245-251
Author(s):  
Bei Ming Zhao ◽  
Miao Hu ◽  
Jun Zhu ◽  
Zhen Yu Han ◽  
Hou Qing Sun ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Process Parameters ◽  
Aging Temperature ◽  
Aging Process ◽  
Production Efficiency ◽  
Holding Time ◽  
Second Stage ◽  
Main Factors ◽  
6082 Aluminum Alloy

The influence of four parameters of two-step aging on the mechanical properties of 6082 aluminum alloy bumper was studied by orthogonal test. The results show that compared with the single stage aging, the two-step aging process can reduce the aging time and improve the production efficiency under the premise of the mechanical properties of the bumper meet the requirements. Among the four aging process parameters, the second stage aging temperature and holding time are the main factors that affect the final results, while the first stage aging temperature and holding time are secondary factors. The most suitable aging process parameters for the 6082 aluminum alloy bumper is (150 °C, 2 h) + (190 °C, 2.5 h). After two-step aging, the grain of the aluminum bumper is small and evenly distributed, leading to good mechanical properties. The generalized experiment shows that the application of the two-step aging process still has some limitations and needs to be further optimized and perfected.

Optimization of a high-pressure microwave curing process for T800/X850 carbon fiber-reinforced plastic

2019 ◽  
Vol 32 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Chenglong Guan ◽  
Lihua Zhan ◽  
Guiming Liu ◽  
Xiaobo Yang ◽  
Guangming Dai ◽  
...  
Keyword(s):  
High Pressure ◽  
Heating Rate ◽  
Process Parameters ◽  
Holding Time ◽  
Curing Temperature ◽  
Measurement Capability ◽  
Microwave Curing ◽  
Trade Offs ◽  
Input Control ◽  
Interlaminar Shear

Compared with the conventional composite curing processes, high-pressure microwave curing is a promising technology. In this study, a set of devices for high-pressure microwave curing was built and equipped with real-time temperature measurement capability and a microwave input control system. The orthogonal experimental method was applied to optimize three process parameters, including the heating rate, curing temperature, and holding time, for the high-pressure microwave curing of T800/X850 composites. The effects of the three parameters on the curing quality were studied by measuring the interlaminar shear strength (ILSS) and conducting differential scanning calorimeter tests. The fracture surface of the samples was also examined by scanning electron microscopy. The results showed that the heating rate had a significant effect on the ILSS of the laminates, and the degree of cure of all samples was more than 95% in the tests. Furthermore, the optimal process parameters were determined as follows: heat up to 170°C with a heating rate of 6°C min−1 and a holding time of 90 min. The total curing time of the sample was 42.4%, and the ILSS of the sample was slightly enhanced by 0.31% compared with standard thermal curing. These results could serve to make trade-offs between reducing manufacturing time and preserving the mechanical properties of microwave-cured composites.

scholarly journals Microwave Sintering of Ti6Al4V: Optimization of Processing Parameters for Maximal Tensile Strength and Minimal Pore Size

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1086 ◽  
Author(s):  
Dilpreet Singh ◽  
Abhishek Rana ◽  
Pawan Sharma ◽  
Pulak Mohan Pandey ◽  
Dinesh Kalyanasundaram
Keyword(s):  
Tensile Strength ◽  
Pore Size ◽  
Heating Rate ◽  
Process Parameters ◽  
Sintering Temperature ◽  
Microwave Sintering ◽  
Compressive Force ◽  
Holding Time ◽  
Minimum Size ◽  
Optimal Process

Pressureless sintering is a powder metallurgical process wherein the powder particles are sintered without the aid of any compressive force. Though this additive manufacturing process is economical, the strength of the component is undermined due to the presence of pores; the elimination of which is a challenge. In this work, the optimal process parameters for the pressureless microwave sintering of a grade 5 titanium alloy that yields higher tensile strength and minimum sizes of pores were obtained. The three process parameters (sintering temperature, heating rate, and holding time) were experimented at five different levels using the design of experiments (DOE). Post sintering, the tensile strength was assessed as per ASTM standard B925-15, while the pore size was evaluated, non-destructively, using micro-computed tomography (μ-CT). The optimal process parameters that yielded minimum size pores were: sintering temperature—1293 °C, heating rate— 6.65 C/minute; and holding time—72 min.

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