EQUILIBRIUM BEHAVIOR OF KRAFT BLACK LIQUOR IN SUPERHEATED STEAM

The boiling point rise (BPR) of black liquor with solids content of 85 to 98% was measured in superheated steam. The BPR for 85 and 95% solids content liquor is 28 and 52°C, respectively. A surprisingly large amount of liquor swelling occurs in this environment. A swelling mechanism is proposed.     

EQUILIBRIUM BEHAVIOR OF KRAFT BLACK LIQUOR IN SUPERHEATED STEAM

The boiling point rise (BPR) of black liquor with solids content of 85 to 98% was measured in superheated steam. The BPR for 85 and 95% solids content liquor is 28 and 52°C, respectively. A surprisingly large amount of liquor swelling occurs in this environment. A swelling mechanism is proposed.     

造纸黑液中木质素在农业领域的应用

介绍了造纸黑液中木质素在农业领域的最新研究及应用,主要对木质素在肥料、农药、饲料、土壤改良剂、植物生长调节剂、液体地膜等方面的研究进展进行了阐述。     

THE INFLUENCE OF COMPOSITION ON THE SWELLING OF KRAFT BLACK LIQUOR DURING PYROLYSIS

During the drying and pyrolysis phases of kraft black liquor combustion, significant swelling of individual liquor particles occurs. Swollen volumes can reach 20 to 30 times the original volume during combustion. The swelling process can affect the combustibility of black liquor and the amount of carryover in a recovery furnace.

The composition of black liquor was found to have a large influence on swelling. A combination of sugar acids and kraft lignin swelled to a larger extent than when either component was pyrolyzed separately. A 1:1 ratio of these two components resulted in maximum swelling for the various ratios tested. The molecular weight of kraft lignin had an effect on swollen volume with higher molecular weight fractions producing lower swelling chars.

Other components were found to reduce the swelling of black liquors. Extractives interfered with the swelling by appearing to change the deformable properties of the pyrolyzing material. Inorganic salts acted as a diluent.

Analysis of the surface characteristics of chars revealed that good swelling chars were composed of small bubbles 50 to 150 microns in diameter. Poor swelling liquors did not exhibit this phenomenon. The formation of bubbles was found to be initiated at 240°C, which closely corresponded to the thermal decomposition temperature of a sugar acid. Kraft lignin appeared to have a major influence on the fluid properties of the pyrolyzing particle. The composition of black liquor determines to a large extent surface forces present in black liquor; these forces are thought to be responsible for the extent to which kraft black liquors deform and swell during pyrolysis.     

PEG-BASED AQUEOUS BIPHASIC SYSTEMS AS IMPROVEMENT FOR KRAFT HARDWOOD PULPING PROCESS

Aqueous biphasic systems (ABS) represent wholly aqueous systems that are safe, nontoxic, nonflammable, and relatively environmentally benign as extraction media. We have studied detailed phase diagrams and partitioning data currently used in wholly aqueous solvent extraction or reactive extraction processes that may be applicable to the delignification of cellulosic materials at elevated temperature. The study results indicate that increasing the concentration of salt improves the degree of phase divergence. The partitioning results of different lignin species in PEG/salt ABS show that lignin prefers the polymer-rich phase of ABS. Four complete time-at-temperature (130-160°C) batch-cooking experiments were made using a Kraft pulping solution with and without PEG. The results for wood chips composed of a mixture of southern hardwood indicate that the use of PEG results in a pulp with lower Kappa number, lower lignin content, higher residual pulp yield, and reduced alkali consumption.     

BEHAVIOR OF EUCALYPTUS GLOBULUS LIGNIN DURING KRAFT PULPING. I. ANALYSIS BY CHEMICAL DEGRADATION METHODS

ABSTRACT

Eucalyptus globulus wood was subjected to kraft pulping, reaching different extents of delignification. The residual and dissolved lignins were isolated by soft acidolysis and acidic precipitation, respectively, and submitted to analysis of residual sugars and methoxyl groups, as well as to analysis by nitrobenzene and permanganate oxidation and thioacidolysis. Results from both residual and dissolved lignins analyses indicated that in the initial phase of pulping there is a preferential removal of lignin enriched in guaiacylpropane (G) and p-hydroxyphenylpropane (H) units, which is highly condensed and bonded with polysaccharides, predominantly with xylan. During the bulk and residual phases of pulping, lignin enriched in syringylpropane (S) units is progressively removed, leading to the increase of S/G ratio of black liquor lignin. After a purification step of dissolved lignins, two fractions with distinct levels of carbohydrates and with different structural features were obtained. The overall results were interpreted in terms of the topochemistry of the kraft pulping process.     

A THERMODYNAMIC MODEL OF THE HEAT CAPACITY OF COMPOSITIONALLY COMPLEX MULTICOMPONENT POLYMER SOLUTIONS: KRAFT BLACK LIQUOR

A thermodynamic model of the heat capacity of multicomponent polymer solutions is developed and applied to the prediction of the heat capacity of kraft black liquor. The model is developed using a pseudo-binary solution assumption. The form of the excess heat capacity is expressed as Cp^E = γWⁿW₁Wm₂ where γ, m, and n are model parameters. For the particular system studied γ varies linearly with temperature and indicates the magnitude and degree of temperature dependence of the excess heat capacity. Parameters m and n are independent of temperature. The resulting model is capable of predicting the heat capacity of compositionally complex black liquor to within 1-3% of the experimental data. @KEYWORDS: Heat capacity, Thermodynamics, Kraft black liquor, Polymer solutions     

SULFUR DIOXIDE-ETHANOL-WATER PULPING OF HARDWOODS

The Tennessee Valley Authority (TVA) has developed a two-stage process to separately convert hemicellulose and cellulose to sugars leaving behind a high-lignin solid residue. Research at The University of Alabama has led to a proposed three-stage process utilizing sulfur dioxide to remove hemicellulose, followed by organosolv delignification to remove lignin and the remaining hemicellulose, then acid hydrolysis of the cellulose to glucose. The purpose of the work presented in this paper was to determine whether the sulfonation and delignification steps could be successfully combined. This would result in a simpler process with improved yield of glucose.

Pulping of hardwoods in a sulfur dioxide-ethanol-water system has been shown to give a 50 to 52 percent yield of solid residue with a lignin content of approximately 7%.These results offer improvements to the TVA process in several ways. Removal of the lignin from the lignocellulose matrix would allow more efficient acid hydrolysis of cellulose and the use of less severe conditions. Delignification also serves to increase yields from enzymatic hydrolysis. Use of an organosolv to remove lignin prior to condensation reactions from acid hydrolysis would produce a lignin product which is more reactive and has higher commercial potential. The results of this work have shown the feasibility of combining the University process with the TVA process while maintaining a two-stage process.     

论官窑对景德镇瓷业发展的贡献

本文对发端于元代，成熟于明、清的景德镇官窑的生产形式、官窑瓷器的艺术特色，民窑的发展与官窑的关系等作了有益的阐述和探索。肯定了官窑对景德镇瓷业发展的历史贡献。     

BEHAVIOR OF EUCALYPTUS GLOBULUS LIGNIN DURING KRAFT PULPING. II. ANALYSIS BY NMR,ESI/MS,AND GPC

ABSTRACT

Residual and dissolved lignin from different phases of kraft delignification of Eucalyptus globulus wood were isolated and characterized by 1D and 2D ¹H NMR, ¹³C NMR, Electrospray Ionization Mass Spectrometry (ESI/MS), and gel permeation chromatography (GPC). During the temperature rise period, below 70°C, about 20% of the lignin was dissolved without significant structural changes. Above 70°C, the lignin suffered significant degradation/fragmentation in the cell wall prior to dissolution. The lignin ether-linked syringyl units were the most susceptible to alkaline degradation. Through the course of pulping, the residual lignin (RL) revealed a gradual increase of aliphatic moieties of unknown structure, as well as a decrease of native structures such as phenylcoumaran and pino-/syringaresinol lignin units. A significant decrease of the β-O-4 structures content in RL was detected only at the final cooking temperature. The lignin dissolved in the black liquor (BL) consisted of highly branched oligomers with rather low molecular weight (average mass 800–1000 u). A part of BL (about 30%) was chemically linked to carbohydrates and possessed a large molecular weight distribution (500–4000 u). BL showed a progressive decrease in β-O-4 and pino-/syringaresinol structures and formation of enol ether and stilbene structures. The GPC analyses showed a continuous decrease of the molecular weight of both the residual and dissolved lignins during the pulping process, particularly in the residual stage.     

A CONTRIBUTION TO THE PREDICTION OF PHASE SEPARATION IN BRANCHING CONDUITS

A phenomenological model for phase separation in branching conduits (Hwang el al., 1988) has been extended and improved. These modifications involve new models for the phase distribution at the inlet of a branching junction corresponding to four different flow regimes, and a correction for flooding in vertical junctions. This mechanistically-based model gives good agreement when compared with representative experimental data.     

A CONTRIBUTION TO THE CHARACTERISTIC DRYING CURVE CONCEPT: APPLICATION TO THE DRYING OF PLASTER

Implicit equations relating the dimensionless drying rate to the reduced moisture content for porous non-hygroscopic slabs have been determined. This study is based on the receding evaporative front model and on the assumption of a parabolic moisture content profile in the diffusional zone of the wet region. The characteristic functions derived depend on the relative position of the receding evaporative front. Two cases were considered : the drying of thick products and the drying of thin products. It has been observed that the relationships corresponding to the C.D.C obtained for thick products depend on the initial. On the other hand, it was observed that experimental CDC. of plaster slabs determined for many thicknesses and various plaster textures depend strongly on these two parameters. Furthermore, the model presented gives good results only for thin products.     

A CONTRIBUTION TO THE CHARACTERISTIC DRYING CURVE CONCEPT: APPLICATION TO THE DRYING OF PLASTER

ABSTRACT

Implicit equations relating the dimensionless drying rate to the reduced moisture content for porous non-hygroscopic slabs have been determined. This study is based on the receding evaporative front model and on the assumption of a parabolic moisture content profile in the diffusional zone of the wet region. The characteristic functions derived depend on the relative position of the receding evaporative front. Two cases were considered : the drying of thick products and the drying of thin products. It has been observed that the relationships corresponding to the C.D.C obtained for thick products depend on the initial. On the other hand, it was observed that experimental CDC. of plaster slabs determined for many thicknesses and various plaster textures depend strongly on these two parameters. Furthermore, the model presented gives good results only for thin products.     

中国早期陶器的出现及其对中华文明的贡献

根据实验数据讨论了中国陶器起源。指出在10,000年前的江西万年仙人洞和河北徐水南庄头等遗址出现的陶器可能就是我国最早的陶器之一。并在此基础上讨论了陶器文化及其发展对中华文明的贡献。     

徽州对景德镇瓷业经济发展的贡献

景德镇与徽州由于地缘相近,水缘相亲,而形成了一种山水相依、文化互通、经济互惠的奇特关系.徼州的商人与艺人以其独有的方式融入到景德镇地方经济中,对窑火的传承与创新付出了巨大的智慧与辛劳.本文从手工业、商业、教育方面论述了微州对景德镇瓷业经济发展的贡献.     

湿固化作用对NCO／OH型双组分聚氨酯涂料漆膜性能的贡献

NCO/OH型聚氨酯漆的固化机制是—NCO与—OH反应交联和—NCO与空气中水分反应交联的叠加。通过同一种NCO/OH聚氨酯漆的漆膜在相同温度而湿度悬殊的环境中固化过程中漆膜性能增长情况的对比,证实了湿固化对漆膜的充分固化与漆膜性能的增长有明显的贡献。     

色丝色含量对其色相的影响

用电脑测色仪分析了不同色含量色丝样品的光谱性质，发现色丝的色相随丝中色料含量的变化而改变，且改变是无规律的；当色含量增减到一定程度时，某些颜色色丝的色相变至肉眼能感觉，即产生色差。