Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed...Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences between fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude (from high to low in elevation). The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis.展开更多
The rheological behavior of low consistency thermomechanical pulp of Chinese fir harvested by intermediate thinning was analyzed. The results show that the apparent viscosity of pulp changed along with the beating deg...The rheological behavior of low consistency thermomechanical pulp of Chinese fir harvested by intermediate thinning was analyzed. The results show that the apparent viscosity of pulp changed along with the beating degree, pulp consistency and shearing velocity. With the increasing of pulp consistency, the apparent viscosity of pulp increased gradually. Beating degree of pulp had an effect on microstructure of pulp. The apparent viscosity of pulp declined as beating degree of pulp increased, and the apparent viscosity of pulp fell along with the shearing velocity increasing. Based on the results, the rheological models are set up. The models showed that the fluid types of the low consistency pulp could be described as pseudoplastics fluids (non-Newtonian fluids).展开更多
CO2 gasification of Fuijian high-metamorphous anthracite with black liquor (BL) and/or mixture of BL and calcium stuff (BL+Ca) as catalyst was studied by using a thermogravimetry under 750-950℃ at ambient pressu...CO2 gasification of Fuijian high-metamorphous anthracite with black liquor (BL) and/or mixture of BL and calcium stuff (BL+Ca) as catalyst was studied by using a thermogravimetry under 750-950℃ at ambient pressure. When the coal was impregnated with an appropriate quantity of Ca and BL mixture, the catalytic activity of CO2 gasification was enhanced obviously. With a loading of 8%Na-BL+2%Ca, the carbon conversion of three coal samples tested reaches up to 92.9%-99.3% at 950℃ within 30min. The continuous formation of alkali surface compounds such as ([-COM], [-CO2M]) and the presence of exchanged Ca, such as calcium phenolate and calcium carboxylates (COO)2Ca, contribute to the increase in catalytic efficiency, and using BL+Ca is more efficient than that adding BL only, The homogeneous model and shrinking-core model were applied to correlate the data of conversion with time and to estimate the reaction rate constants under different temperature. The corresponding reaction activation energy (Ea) and pre-exponential factor of three anthracites were estimated. It is found that Ea is in the range from 73.6 to 121.4kJ·mol^-1 in the case of BL+Ca, and 74.3 to 104.2kJ·mol^-1 when only BL was used as the catalyst, both of which are much less than that from 143.5 to 181.4kJ·mol^-1 if no catalyst used. It is clearly demonstrated that both of BL+Ca mixture and BL could be the source of cheap and effective catalyst for coal gasification.展开更多
The catalytic effects of single and mixed catalysts, i.e. single 3%Ca and 5%Na-BL(black liquor) catalysts and mixed 3%Ca+5%Na-BL catalyst, on carbon conversion, gasification reaction rate constant and activation en...The catalytic effects of single and mixed catalysts, i.e. single 3%Ca and 5%Na-BL(black liquor) catalysts and mixed 3%Ca+5%Na-BL catalyst, on carbon conversion, gasification reaction rate constant and activation energy, relative amount of harmful pollutant like sulphur containing gases have been investigated by thermogravimetry in steam gasification under temperature 750℃ to 950℃ at ambient pressure for three high-metarnorphous anthracites (Longyan, Fenghai and Youxia coals in Fujian Province). The mixed catalyst of 3%Ca+5%Na-BL increases greatly the carbon conversion and gasification rate constant by accelerating the gasification reaction C+H2O→CO+H2 due to presence of alkali surfacecompounds [COM], [CO2M] and exchanged calcium phenolate and calcium carboxylate (-COO)2. By adding CaCO3 into BL catalyst in gasification, in addition to improving the catalyst function and enhancing the carbon conversion, the effective desulphurization is also achieved, but the better operating temperature should be below 900℃. The homogenous and shrinking core models can be successfully employed to correlate the relations between the conversion and the gasification .time .and to estimate the reaction rate constant, The reaction acUvaUon energy and pre-exponential factor are estimated and the activation energy for mixed catalyst is in a range of 98.72-166.92 kJ·mol^-1, much less than 177.50-196.46 kJ·mol^-1 for non-catalytic steam gasification for three experimental coals.展开更多
A study of the effects of the pulp nature on desulphurization and de-ashing during high-sulfur coal flotation is described in this paper. Highlighted are the use of a solution oxygen gauge, a pH value gauge and a surf...A study of the effects of the pulp nature on desulphurization and de-ashing during high-sulfur coal flotation is described in this paper. Highlighted are the use of a solution oxygen gauge, a pH value gauge and a surface tension gauge to investigate changes in the pulp nature related to changes in the oxygen content, the pH value and the interfacial tension. The temperature be- fore and after ultrasonic conditioning was also investigated. The results showed that ultrasonic conditioning resulted in a decrease in the oxygen content and the interracial tension and an increase in the pH value and the temperature of the pulp. The perfect index of flotation and the perfect index of desulphurization of fine coal increased by 25.19% and 18.03%, respectively, after the pulp was ultrasonically conditioned. This study shows that ultrasonic conditioning can change the pulp nature and enhance the degree of desulphurization during high-sulfur coal flotation.展开更多
Sugarcane pulp residue (SPR), a waste from sugar-refinery, which possesses a large surface area, can be used for removing chromium (Cr(Ⅲ) and Cr(Ⅵ)) from wastewater. In this work, the kinetics, isotherms of...Sugarcane pulp residue (SPR), a waste from sugar-refinery, which possesses a large surface area, can be used for removing chromium (Cr(Ⅲ) and Cr(Ⅵ)) from wastewater. In this work, the kinetics, isotherms of Cr(Ⅲ) and Cr(V[) adsorption and their removal by SPR were investigated. The results show that the removal percentages of Cr(Ⅵ) and Cr(Ⅲ) increase with increasing SPR dosage and temperature and decrease with increasing SPR particle size and the initial concentration of chromium ions. However, the influence of pH value on the Cr(Ⅵ) removal differs from that of the Cr(Ⅲ) removal. The Cr(Ⅵ) removal percentage decreases with increasing pH values, while the Cr(Ⅲ) removal percentage increases with increasing pH value. The adsorption kinetics of Cr(Ⅵ) and Cr(Ⅲ) well fits with pseudo-second-order model. Langmuir adsorption isotherm can well describe the adsorption phenomena of chromium ions with the maximum adsorption capacity of 0.567 mg/g for Cr(Ⅵ) and 3.446 mg/g for Cr(Ⅲ). Moreover, SPR reveals higher adsorption capacity for Cr(Ⅲ) than that for Cr(Ⅵ), which implies that SPR has more potential application for Cr(Ⅲ)-containing wastewater treatment than that for Cr(Ⅵ)-containing wastewater treatment.展开更多
It was discussed how refiner plate is produced by a new process, such as three dimension making die with computer technology, shell molding, optimizing the alloy and controlling shakeout time with computer. Results co...It was discussed how refiner plate is produced by a new process, such as three dimension making die with computer technology, shell molding, optimizing the alloy and controlling shakeout time with computer. Results confirmed that lead-time was decreased and product customization was improved in making die by using computer technology. At the same time, precision molding can decrease the reject ratio of refiner plates, and optimizing the alloy and shakeout time can eliminate the need for heat treatment. The new fabricating process showed several advantages over the traditional process in increasing toughness, better casting precision, elimination of the annealing treatment stage and raising production efficiency.展开更多
The bioleaching of pyrrhotite was investigated using Sulfobacillus thermosulfidooxidans.The effects of pH,pulp concentration,inoculation amount,external addition of ferrous and ferric ions were examined.The pH is foun...The bioleaching of pyrrhotite was investigated using Sulfobacillus thermosulfidooxidans.The effects of pH,pulp concentration,inoculation amount,external addition of ferrous and ferric ions were examined.The pH is found to exert a profound effect on the leaching process for controlling the bacterial activity and precipitation of ferric ions mainly as jarosite.The results show that low pulp content increases the leaching rate of iron.The inoculation amount from 1×107 cell/mL to 1×108 cell/mL has positive effects on the leaching rate.The results also imply that addition of ferrous sulfate(1 g/L) is required for the bacteria to efficiently drive the extraction of iron,however,the leaching efficiency has no obvious enhancement when 2 g/L ferrous sulfate was added.Comparatively,addition of ferric sulfate(2 g/L) significantly inhibits the bioleaching process.At the end of bioleaching,jarosite and sulfur are observed on the surface of pyrrhotite residues by using XRD and SEM.With the passivation film formed by jarosite and sulfur,the continuous iron extraction is effectively blocked.展开更多
The flotation characteristics of Shenfu coal macerals was researched. Taking flotation recovery and enrichment of macerals as the evaluation objects, the influence of the agent dosage, pulp concentration, impeller spe...The flotation characteristics of Shenfu coal macerals was researched. Taking flotation recovery and enrichment of macerals as the evaluation objects, the influence of the agent dosage, pulp concentration, impeller speed and aeration rate on the separating effect was investigated. And the optimum process conditions of flotation were confirmed. The results show that the agent dosage, pulp concentration, impeller speed and aeration rate have a significant impact on flotation recovery and en- richment of macerals. The float recovery was 73.28% and enrichment ratio of vitrinite was 83.89% when CTAB dosage of 1.0 kg/t, pulp concentration of 100 g/L, impeller speed of 1 700 r/min and aeration rate of 0.25 m3/(m2·min) were used. The tailings yield was 60.30% and enrichment ratio of inertinite was 61.44% when CTAB dosage of 0.5 kg/t, pulp concentration of 100 g/L, impeller speed of I 700 r/min and aeration rate of 0.20 m3/(m2·min) were used.展开更多
Poly(p-phenylene terephthalamide)(PPTA)pulp was prepared by polycondensation of the p-phenylene diamine(PPDA)with terephthaloyl chloride(TPC)in the completely anhydrous solvent system of N-methyl pyrrolidone(NMP)havin...Poly(p-phenylene terephthalamide)(PPTA)pulp was prepared by polycondensation of the p-phenylene diamine(PPDA)with terephthaloyl chloride(TPC)in the completely anhydrous solvent system of N-methyl pyrrolidone(NMP)having calcium chloride,in the presence of poly(vinyl pyrrolidone)(PVP)having a viscosity average molecular weight lower than 40 000.It was confirmed that the polycondensation could be accelerated,the inherent viscosity of the polymer could be increased,and the polymers could be fibrillated more easily by the addition of the PVP.FTIR and X-ray spectra proved that PVP had not combined into molecular chains of the resultant PPTA pulps.The morphology of the resultant pulps,the effect of viscosity average molecular weight,amount and adding mode of PVP on inherent viscosity,specific surface area,and mean length of the resultant pulps were discussed in detail.And the friction and wear properties of the compound reinforced by the resultant pulps were simply investigated.展开更多
Amylolytic enzymes are currently investigated to improve industrial processes of starch degradation. Saccharomyces diastaticus 2047 isolated from cassava waste showed amylase and glucoamylase production, using starch ...Amylolytic enzymes are currently investigated to improve industrial processes of starch degradation. Saccharomyces diastaticus 2047 isolated from cassava waste showed amylase and glucoamylase production, using starch medium, and the highest rate was obtained in the initial growth phase, after incubation for 24 h at pH 5.5. Maximum amylase and glucoamylase activities (483.62 U mg^-1 protein and 290.85 U mg^-1 protein) were obtained at pH 5.5. The isolated enzymes exhibited thermostable properties as indicated by retention of 100% of residual activity at 55 ℃ for 45 min with total inhibition at 100 ℃. Extracellular enzyme from S diastaticus 2047 was partially purified by fractionated precipitation with ammonium sulphate. After 40% saturation produced 2,197.00 and 1,192.83 U/mg protein, and yield was 40% with purification 4.54 and 4.1 fold, respectively. This study presents feasibility on ethanol production from cassava pulps pretreated with diluted sulfuric acid by simultaneous saccharification and fermentation (SSF) with S. diastaticus 2047. The results indicated that the culture was able to produce ethanol with high yield without amylolytic enzyme adding by using cassava pulps pretreated with distilled water at 135 ℃ under pressure of 15 lb/inch^2 to produce ethanol yield as high as the cassava pulps pretreated with diluted sulfuric acid under the same condition. This suggests that S diastaticus with enzyme produced has potential for industrial applications.展开更多
The liquid effluents released from several industries including the pulp and paper industries contain phenol and phenolic compounds. The hazardous phenols and their chlorinated phenolic derivatives from pulp and paper...The liquid effluents released from several industries including the pulp and paper industries contain phenol and phenolic compounds. The hazardous phenols and their chlorinated phenolic derivatives from pulp and paper industries bear the potential to exert deleterious effects on the human health and aquatic ecosystems, if they are released untreated in the environment. Biodegradation of phenolic compounds in the effluent streams from pulp and paper industries is an important eco-friendly method for the removal of toxicity in industrial waste water, while the minimization of formation of these toxic compounds require several in-plant biotechnological techniques such as biopulping and biobleaching. Present paper reviews, the biochemical pathways involved in degradation of phenols and chlorophenols through microorganisms. Various biotechnological strategies involved in minimization and biodegradation of phenol and phenolic compounds and their related environmental engineering aspects such as utility of different bioreactor configurations have been discussed for the treatment of pulp and paper mill effluents.展开更多
In this study, the superoxide anion radicals were generated by the auto-oxidation of 1,2,3-trihydroxybenzene and determined by UV spectrophotometry, and the reaction was found to be facilitated by anthraquinone-2-sulf...In this study, the superoxide anion radicals were generated by the auto-oxidation of 1,2,3-trihydroxybenzene and determined by UV spectrophotometry, and the reaction was found to be facilitated by anthraquinone-2-sulfonic acid sodium salt. The bamboo kraft pulps were treated by the 1,2,3-trihydroxybenzene auto-oxidation method or the 1,2,3-trihydroxybenzene auto-oxidation combined with anthraquinone-2-sulfonic acid sodium salt to show the ef-fect of the superoxide anion radicals during the oxygen delignification of bamboo kraft pulp and the enhancing af-fect of anthraquinone compounds as an additive on delignification. The results indicated that the superoxide anion radicals could react with lignin and remove it from pulp with negligible damage on cellulose, and the an-thraquinone-2-sulfonic acid sodium salt could facilitate the generation of superoxide anion radical to enhance delig-nification of pulps. The oxygen delignification selectivity could be improved using the 1,2,3-trihydroxybenzene auto-oxidation system combined with anthraquinone-2-sulfonic acid sodium salt.展开更多
A numerical method for predicting fiber orientation is presented to explore the flow properties of turbulent fiber suspension flowing through a stock pump impeller. The Fokker-Planck equation is used to describe the d...A numerical method for predicting fiber orientation is presented to explore the flow properties of turbulent fiber suspension flowing through a stock pump impeller. The Fokker-Planck equation is used to describe the distribution of fiber orientation. The effect of flow-fiber coupling is considered by modifying the constitutive mode.The three-dimensional orientation distribution function is formulated and the corresponding equations are solved in terms of second-order and fourth-order orientation tensors. The evolution of fiber orientation, flow velocity and pressure, additional shear stress and normal stress difference are presented. The results show that the evolutions of fiber orientation are different along different streamlines. The velocity and its gradient are large in the concave wall region, while they are very small in the convex wall region. The additional shear stress and normal stress difference are large in the inlet and concave wall regions, and moderate in the mid-region, while they are almost zero in most downstream regions. The non-equilibrium fiber orientation distribution is dominant at the inlet and the concave wall regions. The flow will consume more energy to overcome the additional shearing losses due to fibers at the inlet and the concave wall regions. The change of flow rates has effect on the distribution of additional shear stress and normal stress difference. The flow structure in the inlet and concave wall regions is essential in the resultant rheological properties of the fiber suspension through the stock pump impeller, which will directly affect the flow efficiency of the fiber suspension through the impeller.展开更多
It has been reported that natural cellulose (cellulose I) can not be oxidized by TEMPO - NaOCI - NaBr system, one of TEMPO-mediated selective oxidant systems, but regenerated cellulose (cellulose Ⅱ ) can be compl...It has been reported that natural cellulose (cellulose I) can not be oxidized by TEMPO - NaOCI - NaBr system, one of TEMPO-mediated selective oxidant systems, but regenerated cellulose (cellulose Ⅱ ) can be completely selectively oxidized. In the present work, natural cellulose pulp was treated with NaOH solution, which concentration is lower than 20 wt%. The alkaline celluloses obtained were oxidized by TEMPO - NaOCI - NaBr system and the factors which influence the selective oxidation reaction rate have been investigated. The structure of the oxidized products has been characterized by Fourier transform-infrared (FTIR), nuclear magenatic resonace (NMR) and wide angle X-ray diffraction (WAXD) methods, and their adsorption properties for Cu^2+ and Cd^2+ in aqueous solutions have been preliminarily examined. The results show that after the alkaline treatment, the primary hydroxyl at C6 position of natural cellulose can be selectively oxidized to carboxyl group in the reaction medium at pH 10.8, the oxidation rate becomes greater with the NaOH concentration and alkaline treatment time increasing. The alkaline treatment has a great effect on the crystal structure of natural cellulose, but the crystal structure of alkaline cellulose keeps almost unchanged after oxidation. The adsorption capacity is enhanced by introducing carboxyl groups into the cellulose macromolecular chains.展开更多
The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additiv...The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additives--chemicals, black mold enzyme, and chemicals together with black mold enzyme, are studied. The first part of the experiment was to find the optimal amount of chemicals and the optimal pH through the use of sodium hydroxide and surfactant. As a result, 0.2% of sodium hydroxide and 0.4% of surfactant on oven dried weight at pH 9 was found to be the optimal condition for the deinked pulp to yield the lowest ERIC (effective residual concentration) and the highest brightness. The second part of the experiment was to find the optimal amount of black mold enzyme used in the deinking process. As a result, the optimal condition for deinked pulp to retain the lowest ERIC and the highest brightness was 100 ppm of black mold enzyme and 10 minutes of enzyme reaction time. The third part of experiment was to study the de-inking ability of black mold enzyme and chemicals. Consequently, with 30 min of chemicals reaction time and 60 min of black mold reaction time, the deinked pulp retained low ERIC but higher brightness.展开更多
In this study, single and interactive effect of three parameters, pH, ferrous and pulp concentration has been investigated by a 2^3 full factorial CCRD (central composite rotatable design) composed of eight factoria...In this study, single and interactive effect of three parameters, pH, ferrous and pulp concentration has been investigated by a 2^3 full factorial CCRD (central composite rotatable design) composed of eight factorial points, six central and six axial points. Initially, "none" mode from transformation subsection was chosen as the default choice for both responses, i.e. %recovery and gram of recovered zinc. Box-Cox plots give the best Lambda for each response (y^Lambda= f (A, B, C .....)) which occur at 1.91 and 2.16 for %recovey and gram of recovered zinc, respectively. A linear (y^1.91 = f (linear)) and a quadratic (y^2. 16= f (quadratic)) equation were suggested by software as the model for %recovery and gram of recovered zinc, respectively. Analysis of variance (ANOVA) for both models shows a high coefficient of determination (R^2). In order to optimize and find the best conditions under which three parameters occur appropriately, optimization was done numerically. Desirability plots indicate properly that the best conditions occur at pH = 1.46, ferrous = 6.67 g/L, %pulp = 7.1 (%w/v), %recovery = 86.5, gram of recovered zinc = 0.63 g and desirability = 0.777. Finally, PRP (progressive route of the process) analysis donates us a proper insight of what is happening during these 30 days. PRP analysis categorizes flasks in two parts, 1- flasks worth economically, 2- flasks with one-time-usable feed materials.展开更多
The implementation of the European WFD (water framework directive) requires IWRM (integrated water resource management), an important tool in managing available water resources in the presence of emerging constrai...The implementation of the European WFD (water framework directive) requires IWRM (integrated water resource management), an important tool in managing available water resources in the presence of emerging constraints. Pressures caused by variability in water supply cycles, droughts, pollution, industrialization, increasing domestic and commercial demand, inadequate infrastructure, intense urbanization and population growth, and decrepit distribution networks have led to the increasing exploitation of industrial wastewater. Most industrial process has some negative impacts on the environment especially on a catchment scale i.e. water, air and soil quality. In the context of water resources and environmental protection measures, the term "sustainable development", a development that is compatible with the future gains and environmental protection, is regulated more and more by law. To comply with these emission-based limit values, so-called "end-of-pipe-techniques" are used. Experimental results show CBT (continuous biological treatment) processes present secondary measures to purify highly contaminated industrial wastewater.展开更多
基金funded by both of the Interna-tional Tropical Timber Organization (ITTO), grant No. PD10/00. REV.2 (I,F)the National‘Tenth Five-year’Key Program of China, grant No. 2004BA506B0103
文摘Using 3-year-old culms of 8 provenances of Bambusa chungii from Guangdong, Guangxi and Hainan Provinces, the indexes of wood properties, such as fiber dimensions and chemical composition were investigated and analyzed by the methods of Analysis of variance and correlation coefficient to reveal the geographic genetic variation situation. The results showed that there are significant differences between fiber length, fibrin and 1% NaOH extraction contents of B. chungii from 8 provenances; moreover, the fiber length and fiber length/width ratio had a decreasing change pattern with geographic variation from the south to the north in altitude (from high to low in elevation). The heritabilities for fibrin, fiber length, 1% NaOH extractive, lignin and fiber length/width ratio were 0.7, 0.84, 0.54, 0.38 and 0.13, respectively. A significant negative correlation was found between 1% NaOH extraction, benzo-alcohol extraction contents and bamboo culm yield, whereas there was a significant positive correlation between fibrin contents and bamboo wood yield. Besides, a close correlation was detected between fiber dimensions indices and bamboo growth or bamboo wood yield. Finally, three provenances with high qualities and culm yield, i.e. Huaiji, Xinyi and Guilin, were selected as superior sources based on principal component analysis.
基金This study was sponsored by the Research Funding for Outstanding Young University Faculty of China Ministry of Education (No. 2001-39), Fujian Provincial Innovation Fundation for Young Science and Technology Talents (No. 2004J012), and the National Natural Science Funda-tion of China (No. 30571461)
文摘The rheological behavior of low consistency thermomechanical pulp of Chinese fir harvested by intermediate thinning was analyzed. The results show that the apparent viscosity of pulp changed along with the beating degree, pulp consistency and shearing velocity. With the increasing of pulp consistency, the apparent viscosity of pulp increased gradually. Beating degree of pulp had an effect on microstructure of pulp. The apparent viscosity of pulp declined as beating degree of pulp increased, and the apparent viscosity of pulp fell along with the shearing velocity increasing. Based on the results, the rheological models are set up. The models showed that the fluid types of the low consistency pulp could be described as pseudoplastics fluids (non-Newtonian fluids).
基金Supported by the National Natural Science Foundation of China (No.20376014) and Fujian Science and Technology Council Grant (HG99-01).
文摘CO2 gasification of Fuijian high-metamorphous anthracite with black liquor (BL) and/or mixture of BL and calcium stuff (BL+Ca) as catalyst was studied by using a thermogravimetry under 750-950℃ at ambient pressure. When the coal was impregnated with an appropriate quantity of Ca and BL mixture, the catalytic activity of CO2 gasification was enhanced obviously. With a loading of 8%Na-BL+2%Ca, the carbon conversion of three coal samples tested reaches up to 92.9%-99.3% at 950℃ within 30min. The continuous formation of alkali surface compounds such as ([-COM], [-CO2M]) and the presence of exchanged Ca, such as calcium phenolate and calcium carboxylates (COO)2Ca, contribute to the increase in catalytic efficiency, and using BL+Ca is more efficient than that adding BL only, The homogeneous model and shrinking-core model were applied to correlate the data of conversion with time and to estimate the reaction rate constants under different temperature. The corresponding reaction activation energy (Ea) and pre-exponential factor of three anthracites were estimated. It is found that Ea is in the range from 73.6 to 121.4kJ·mol^-1 in the case of BL+Ca, and 74.3 to 104.2kJ·mol^-1 when only BL was used as the catalyst, both of which are much less than that from 143.5 to 181.4kJ·mol^-1 if no catalyst used. It is clearly demonstrated that both of BL+Ca mixture and BL could be the source of cheap and effective catalyst for coal gasification.
基金Supported by the National Natural Science Foundation of China (20376014) and Fujian Science and Technology Council Grant (HG99-01 ).
文摘The catalytic effects of single and mixed catalysts, i.e. single 3%Ca and 5%Na-BL(black liquor) catalysts and mixed 3%Ca+5%Na-BL catalyst, on carbon conversion, gasification reaction rate constant and activation energy, relative amount of harmful pollutant like sulphur containing gases have been investigated by thermogravimetry in steam gasification under temperature 750℃ to 950℃ at ambient pressure for three high-metarnorphous anthracites (Longyan, Fenghai and Youxia coals in Fujian Province). The mixed catalyst of 3%Ca+5%Na-BL increases greatly the carbon conversion and gasification rate constant by accelerating the gasification reaction C+H2O→CO+H2 due to presence of alkali surfacecompounds [COM], [CO2M] and exchanged calcium phenolate and calcium carboxylate (-COO)2. By adding CaCO3 into BL catalyst in gasification, in addition to improving the catalyst function and enhancing the carbon conversion, the effective desulphurization is also achieved, but the better operating temperature should be below 900℃. The homogenous and shrinking core models can be successfully employed to correlate the relations between the conversion and the gasification .time .and to estimate the reaction rate constant, The reaction acUvaUon energy and pre-exponential factor are estimated and the activation energy for mixed catalyst is in a range of 98.72-166.92 kJ·mol^-1, much less than 177.50-196.46 kJ·mol^-1 for non-catalytic steam gasification for three experimental coals.
基金Projects 50274036 supported by the National Natural Science Foundation of China11531Z02 by the Educational Committee of Heilongjiang Province2009RFXXG030 by the Special Foundation of Harbin Bureau of Science and Technology
文摘A study of the effects of the pulp nature on desulphurization and de-ashing during high-sulfur coal flotation is described in this paper. Highlighted are the use of a solution oxygen gauge, a pH value gauge and a surface tension gauge to investigate changes in the pulp nature related to changes in the oxygen content, the pH value and the interfacial tension. The temperature be- fore and after ultrasonic conditioning was also investigated. The results showed that ultrasonic conditioning resulted in a decrease in the oxygen content and the interracial tension and an increase in the pH value and the temperature of the pulp. The perfect index of flotation and the perfect index of desulphurization of fine coal increased by 25.19% and 18.03%, respectively, after the pulp was ultrasonically conditioned. This study shows that ultrasonic conditioning can change the pulp nature and enhance the degree of desulphurization during high-sulfur coal flotation.
基金Projects(2006AA06Z374, 2007AA021304) supported by the National High-Tech Research and Development Program of ChinaProject(2008SK2007) supported by the Key Program of Science and Technology of Hunan Province, China
文摘Sugarcane pulp residue (SPR), a waste from sugar-refinery, which possesses a large surface area, can be used for removing chromium (Cr(Ⅲ) and Cr(Ⅵ)) from wastewater. In this work, the kinetics, isotherms of Cr(Ⅲ) and Cr(V[) adsorption and their removal by SPR were investigated. The results show that the removal percentages of Cr(Ⅵ) and Cr(Ⅲ) increase with increasing SPR dosage and temperature and decrease with increasing SPR particle size and the initial concentration of chromium ions. However, the influence of pH value on the Cr(Ⅵ) removal differs from that of the Cr(Ⅲ) removal. The Cr(Ⅵ) removal percentage decreases with increasing pH values, while the Cr(Ⅲ) removal percentage increases with increasing pH value. The adsorption kinetics of Cr(Ⅵ) and Cr(Ⅲ) well fits with pseudo-second-order model. Langmuir adsorption isotherm can well describe the adsorption phenomena of chromium ions with the maximum adsorption capacity of 0.567 mg/g for Cr(Ⅵ) and 3.446 mg/g for Cr(Ⅲ). Moreover, SPR reveals higher adsorption capacity for Cr(Ⅲ) than that for Cr(Ⅵ), which implies that SPR has more potential application for Cr(Ⅲ)-containing wastewater treatment than that for Cr(Ⅵ)-containing wastewater treatment.
文摘It was discussed how refiner plate is produced by a new process, such as three dimension making die with computer technology, shell molding, optimizing the alloy and controlling shakeout time with computer. Results confirmed that lead-time was decreased and product customization was improved in making die by using computer technology. At the same time, precision molding can decrease the reject ratio of refiner plates, and optimizing the alloy and shakeout time can eliminate the need for heat treatment. The new fabricating process showed several advantages over the traditional process in increasing toughness, better casting precision, elimination of the annealing treatment stage and raising production efficiency.
基金Project(2010CB630903) supported by the National Basic Research Program of China
文摘The bioleaching of pyrrhotite was investigated using Sulfobacillus thermosulfidooxidans.The effects of pH,pulp concentration,inoculation amount,external addition of ferrous and ferric ions were examined.The pH is found to exert a profound effect on the leaching process for controlling the bacterial activity and precipitation of ferric ions mainly as jarosite.The results show that low pulp content increases the leaching rate of iron.The inoculation amount from 1×107 cell/mL to 1×108 cell/mL has positive effects on the leaching rate.The results also imply that addition of ferrous sulfate(1 g/L) is required for the bacteria to efficiently drive the extraction of iron,however,the leaching efficiency has no obvious enhancement when 2 g/L ferrous sulfate was added.Comparatively,addition of ferric sulfate(2 g/L) significantly inhibits the bioleaching process.At the end of bioleaching,jarosite and sulfur are observed on the surface of pyrrhotite residues by using XRD and SEM.With the passivation film formed by jarosite and sulfur,the continuous iron extraction is effectively blocked.
文摘The flotation characteristics of Shenfu coal macerals was researched. Taking flotation recovery and enrichment of macerals as the evaluation objects, the influence of the agent dosage, pulp concentration, impeller speed and aeration rate on the separating effect was investigated. And the optimum process conditions of flotation were confirmed. The results show that the agent dosage, pulp concentration, impeller speed and aeration rate have a significant impact on flotation recovery and en- richment of macerals. The float recovery was 73.28% and enrichment ratio of vitrinite was 83.89% when CTAB dosage of 1.0 kg/t, pulp concentration of 100 g/L, impeller speed of 1 700 r/min and aeration rate of 0.25 m3/(m2·min) were used. The tailings yield was 60.30% and enrichment ratio of inertinite was 61.44% when CTAB dosage of 0.5 kg/t, pulp concentration of 100 g/L, impeller speed of I 700 r/min and aeration rate of 0.20 m3/(m2·min) were used.
文摘Poly(p-phenylene terephthalamide)(PPTA)pulp was prepared by polycondensation of the p-phenylene diamine(PPDA)with terephthaloyl chloride(TPC)in the completely anhydrous solvent system of N-methyl pyrrolidone(NMP)having calcium chloride,in the presence of poly(vinyl pyrrolidone)(PVP)having a viscosity average molecular weight lower than 40 000.It was confirmed that the polycondensation could be accelerated,the inherent viscosity of the polymer could be increased,and the polymers could be fibrillated more easily by the addition of the PVP.FTIR and X-ray spectra proved that PVP had not combined into molecular chains of the resultant PPTA pulps.The morphology of the resultant pulps,the effect of viscosity average molecular weight,amount and adding mode of PVP on inherent viscosity,specific surface area,and mean length of the resultant pulps were discussed in detail.And the friction and wear properties of the compound reinforced by the resultant pulps were simply investigated.
文摘Amylolytic enzymes are currently investigated to improve industrial processes of starch degradation. Saccharomyces diastaticus 2047 isolated from cassava waste showed amylase and glucoamylase production, using starch medium, and the highest rate was obtained in the initial growth phase, after incubation for 24 h at pH 5.5. Maximum amylase and glucoamylase activities (483.62 U mg^-1 protein and 290.85 U mg^-1 protein) were obtained at pH 5.5. The isolated enzymes exhibited thermostable properties as indicated by retention of 100% of residual activity at 55 ℃ for 45 min with total inhibition at 100 ℃. Extracellular enzyme from S diastaticus 2047 was partially purified by fractionated precipitation with ammonium sulphate. After 40% saturation produced 2,197.00 and 1,192.83 U/mg protein, and yield was 40% with purification 4.54 and 4.1 fold, respectively. This study presents feasibility on ethanol production from cassava pulps pretreated with diluted sulfuric acid by simultaneous saccharification and fermentation (SSF) with S. diastaticus 2047. The results indicated that the culture was able to produce ethanol with high yield without amylolytic enzyme adding by using cassava pulps pretreated with distilled water at 135 ℃ under pressure of 15 lb/inch^2 to produce ethanol yield as high as the cassava pulps pretreated with diluted sulfuric acid under the same condition. This suggests that S diastaticus with enzyme produced has potential for industrial applications.
文摘The liquid effluents released from several industries including the pulp and paper industries contain phenol and phenolic compounds. The hazardous phenols and their chlorinated phenolic derivatives from pulp and paper industries bear the potential to exert deleterious effects on the human health and aquatic ecosystems, if they are released untreated in the environment. Biodegradation of phenolic compounds in the effluent streams from pulp and paper industries is an important eco-friendly method for the removal of toxicity in industrial waste water, while the minimization of formation of these toxic compounds require several in-plant biotechnological techniques such as biopulping and biobleaching. Present paper reviews, the biochemical pathways involved in degradation of phenols and chlorophenols through microorganisms. Various biotechnological strategies involved in minimization and biodegradation of phenol and phenolic compounds and their related environmental engineering aspects such as utility of different bioreactor configurations have been discussed for the treatment of pulp and paper mill effluents.
基金Supported by the National Natural Science Foundation of China (No.20477046)the Natural Science Foundation of Fujian Prov-ince of China (No.2004HZ03-5)the Young Scientist Innovation Foundation of Fujian Province of China (No.2006F3009).
文摘In this study, the superoxide anion radicals were generated by the auto-oxidation of 1,2,3-trihydroxybenzene and determined by UV spectrophotometry, and the reaction was found to be facilitated by anthraquinone-2-sulfonic acid sodium salt. The bamboo kraft pulps were treated by the 1,2,3-trihydroxybenzene auto-oxidation method or the 1,2,3-trihydroxybenzene auto-oxidation combined with anthraquinone-2-sulfonic acid sodium salt to show the ef-fect of the superoxide anion radicals during the oxygen delignification of bamboo kraft pulp and the enhancing af-fect of anthraquinone compounds as an additive on delignification. The results indicated that the superoxide anion radicals could react with lignin and remove it from pulp with negligible damage on cellulose, and the an-thraquinone-2-sulfonic acid sodium salt could facilitate the generation of superoxide anion radical to enhance delig-nification of pulps. The oxygen delignification selectivity could be improved using the 1,2,3-trihydroxybenzene auto-oxidation system combined with anthraquinone-2-sulfonic acid sodium salt.
基金Supported by the National Natural Science Foundation of China (51309118), the National Key Technology R&D Program of the Ministry of Science and Technology of China (2011BAF14B01), the Postdoctoral Science Foundation of China (2013M531282) and the Doctorate Program of Higher Education of China (20120101110121).
文摘A numerical method for predicting fiber orientation is presented to explore the flow properties of turbulent fiber suspension flowing through a stock pump impeller. The Fokker-Planck equation is used to describe the distribution of fiber orientation. The effect of flow-fiber coupling is considered by modifying the constitutive mode.The three-dimensional orientation distribution function is formulated and the corresponding equations are solved in terms of second-order and fourth-order orientation tensors. The evolution of fiber orientation, flow velocity and pressure, additional shear stress and normal stress difference are presented. The results show that the evolutions of fiber orientation are different along different streamlines. The velocity and its gradient are large in the concave wall region, while they are very small in the convex wall region. The additional shear stress and normal stress difference are large in the inlet and concave wall regions, and moderate in the mid-region, while they are almost zero in most downstream regions. The non-equilibrium fiber orientation distribution is dominant at the inlet and the concave wall regions. The flow will consume more energy to overcome the additional shearing losses due to fibers at the inlet and the concave wall regions. The change of flow rates has effect on the distribution of additional shear stress and normal stress difference. The flow structure in the inlet and concave wall regions is essential in the resultant rheological properties of the fiber suspension through the stock pump impeller, which will directly affect the flow efficiency of the fiber suspension through the impeller.
文摘It has been reported that natural cellulose (cellulose I) can not be oxidized by TEMPO - NaOCI - NaBr system, one of TEMPO-mediated selective oxidant systems, but regenerated cellulose (cellulose Ⅱ ) can be completely selectively oxidized. In the present work, natural cellulose pulp was treated with NaOH solution, which concentration is lower than 20 wt%. The alkaline celluloses obtained were oxidized by TEMPO - NaOCI - NaBr system and the factors which influence the selective oxidation reaction rate have been investigated. The structure of the oxidized products has been characterized by Fourier transform-infrared (FTIR), nuclear magenatic resonace (NMR) and wide angle X-ray diffraction (WAXD) methods, and their adsorption properties for Cu^2+ and Cd^2+ in aqueous solutions have been preliminarily examined. The results show that after the alkaline treatment, the primary hydroxyl at C6 position of natural cellulose can be selectively oxidized to carboxyl group in the reaction medium at pH 10.8, the oxidation rate becomes greater with the NaOH concentration and alkaline treatment time increasing. The alkaline treatment has a great effect on the crystal structure of natural cellulose, but the crystal structure of alkaline cellulose keeps almost unchanged after oxidation. The adsorption capacity is enhanced by introducing carboxyl groups into the cellulose macromolecular chains.
文摘The aim of this research is to study the floatation deinking abilities of black mold enzyme and chemicals in newsprint paper application. In this experiment, the properties of deinked pulp from three different additives--chemicals, black mold enzyme, and chemicals together with black mold enzyme, are studied. The first part of the experiment was to find the optimal amount of chemicals and the optimal pH through the use of sodium hydroxide and surfactant. As a result, 0.2% of sodium hydroxide and 0.4% of surfactant on oven dried weight at pH 9 was found to be the optimal condition for the deinked pulp to yield the lowest ERIC (effective residual concentration) and the highest brightness. The second part of the experiment was to find the optimal amount of black mold enzyme used in the deinking process. As a result, the optimal condition for deinked pulp to retain the lowest ERIC and the highest brightness was 100 ppm of black mold enzyme and 10 minutes of enzyme reaction time. The third part of experiment was to study the de-inking ability of black mold enzyme and chemicals. Consequently, with 30 min of chemicals reaction time and 60 min of black mold reaction time, the deinked pulp retained low ERIC but higher brightness.
文摘In this study, single and interactive effect of three parameters, pH, ferrous and pulp concentration has been investigated by a 2^3 full factorial CCRD (central composite rotatable design) composed of eight factorial points, six central and six axial points. Initially, "none" mode from transformation subsection was chosen as the default choice for both responses, i.e. %recovery and gram of recovered zinc. Box-Cox plots give the best Lambda for each response (y^Lambda= f (A, B, C .....)) which occur at 1.91 and 2.16 for %recovey and gram of recovered zinc, respectively. A linear (y^1.91 = f (linear)) and a quadratic (y^2. 16= f (quadratic)) equation were suggested by software as the model for %recovery and gram of recovered zinc, respectively. Analysis of variance (ANOVA) for both models shows a high coefficient of determination (R^2). In order to optimize and find the best conditions under which three parameters occur appropriately, optimization was done numerically. Desirability plots indicate properly that the best conditions occur at pH = 1.46, ferrous = 6.67 g/L, %pulp = 7.1 (%w/v), %recovery = 86.5, gram of recovered zinc = 0.63 g and desirability = 0.777. Finally, PRP (progressive route of the process) analysis donates us a proper insight of what is happening during these 30 days. PRP analysis categorizes flasks in two parts, 1- flasks worth economically, 2- flasks with one-time-usable feed materials.
文摘The implementation of the European WFD (water framework directive) requires IWRM (integrated water resource management), an important tool in managing available water resources in the presence of emerging constraints. Pressures caused by variability in water supply cycles, droughts, pollution, industrialization, increasing domestic and commercial demand, inadequate infrastructure, intense urbanization and population growth, and decrepit distribution networks have led to the increasing exploitation of industrial wastewater. Most industrial process has some negative impacts on the environment especially on a catchment scale i.e. water, air and soil quality. In the context of water resources and environmental protection measures, the term "sustainable development", a development that is compatible with the future gains and environmental protection, is regulated more and more by law. To comply with these emission-based limit values, so-called "end-of-pipe-techniques" are used. Experimental results show CBT (continuous biological treatment) processes present secondary measures to purify highly contaminated industrial wastewater.