PENETRATION DURING SULPHITE COOKING

1933 ◽  
Vol 8 (5) ◽  
pp. 415-428 ◽  
Author(s):  
H. Saunderson ◽  
H. W. Johnston ◽  
O. Maass
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Experimental Technique ◽  
Sulphur Dioxide ◽  
Surface Effect ◽  
Rate Of Penetration ◽  
Spruce Wood ◽  
Cooking Process ◽  
Free Sulphur ◽  
Opening Up

This paper deals with some of the factors which influence the penetration of sulphite liquor into wood during the cooking process. The experimental technique for this purpose is described. The particular factors investigated in this paper are the influence of the calcium sulphite precipitate and the composition of the liquor on penetration.Certain conclusions may be drawn from the experimental results presented. These are summarized as follows:(1) The rate of penetration of sulphite liquor through a block of spruce wood is constant for a fixed low temperature. At a constant high temperature the rate of penetration increases continuously during the duration of a run, due to the opening up of the wood. This "cooking" action becomes evident at about 90 °C. for heartwood, and below 70 °C. for sapwood.(2) The rate of penetration of sulphite liquor is greater for a higher concentration of free sulphur dioxide. This increase in rate with sulphur dioxide concentration becomes more noticeable at higher temperatures, indicating that at least a part of the effect is due to cooking action.(3) The formation of a precipitate of calcium sulphite on the wood at high temperatures decreases the rate of forced penetration. This effect is more noticeable with porous wood, where the pressure differential is small. The plugging action is largely a surface effect, due to the formation of a layer of precipitate over the ends of the tracheids of the wood.

INVESTIGATION OF VARIOUS PHYSICO-CHEMICAL FACTORS WHICH INFLUENCE SULPHITE COOKING

1934 ◽  
Vol 10 (1) ◽  
pp. 24-35 ◽  
Author(s):  
H. H. Saunderson ◽  
O. Maass
Keyword(s):  
Low Temperature ◽  
Sulphur Dioxide ◽  
Spruce Wood ◽  
Physico Chemical ◽  
Free Sulphur ◽  
Chemical Factors

The penetration of aqueous sulphite solutions into differently shaped blocks of spruce wood has been investigated, the effect of the shape and type of wood, and of the presence of imprisoned air being determined. Measurements of the rates of diffusion of the constituents of calcium bisulphite solutions into pre-soaked blocks of wood showed that "free" sulphur dioxide diffused more readily than calcium bisulphite. Adsorption of sulphur dioxide and calcium bisulphite solutions by spruce wood was measured at 30° and 50 °C., and the influence of this factor on penetration was determined. The effect of penetration on delignification indicated the necessity of a satisfactory distribution of the lime salt at a low temperature to avoid localization of the lime during the pulping process.

THE EFFECT OF MAGNESIUM-BASE SULPHITE-LIQUOR COMPOSITION ON THE RATE OF DELIGNIFICATION OF SPRUCE WOOD AND YIELD OF PULP

1938 ◽  
Vol 16b (7) ◽  
pp. 242-252
Author(s):  
J. M. Calhoun ◽  
J. J. R. Cannon ◽  
F. H. Yorston ◽  
O. Maass
Keyword(s):  
Sulphur Dioxide ◽  
Lignin Content ◽  
Simple Equation ◽  
Type Formula ◽  
Wood Meal ◽  
Spruce Wood ◽  
Rate Of Reaction ◽  
Mole Percentage ◽  
Free Sulphur

The rate of delignification of resin extracted spruce wood-meal in magnesium base sulphite liquor has been determined at 130 °C. over the concentration range 0.5 to 4% combined, and 2 to 10% free, sulphur dioxide. The rate of reaction is roughly proportional to the concentration of free sulphur dioxide when the combined is constant, but decreases with increase in the concentration of combined when the free is constant. The relation of the rate of delignification to the liquor composition cannot be expressed by any simple equation of the type:[Formula: see text]where K and n are constants. The rate of cooking is somewhat greater in magnesium base sulphite liquor than in calcium base liquor of the same mole percentage composition.The yield of pulp at any given lignin content is independent of the free sulphur dioxide over the whole concentration range, but increases with increase in the concentration of the combined to a maximum at about 3%, and decreases at slightly higher concentrations. When the concentration of combined sulphur dioxide is greater than 1% the yield of pulp obtained from magnesium base cooks is slightly higher than that from corresponding calcium base cooks.

THE EFFECT OF SULPHITE LIQUOR COMPOSITION ON THE RATE OF DELIGNIFICATION OF SPRUCE WOOD AND YIELD OF PULP

1937 ◽  
Vol 15b (11) ◽  
pp. 457-474 ◽  
Author(s):  
J. M. Calhoun ◽  
F. H. Yorston ◽  
O. Maass
Keyword(s):  
Sulphur Dioxide ◽  
Lignin Content ◽  
Order Relation ◽  
Ion Concentration ◽  
Quantitative Relation ◽  
Systematic Deviation ◽  
Hydrogen Ion Concentration ◽  
First Order ◽  
Spruce Wood ◽  
Free Sulphur

A technique has been devised for studying the delignification of wood in sulphite liquor under accurately controlled conditions. The rate of delignification of resin extracted spruce wood-meal has been determined at 130 °C. over the concentration range 0.2 to 1.4% combined, and 2 to 14% total, sulphur dioxide. The reaction shows a systematic deviation from the first order relation that is the same for any composition of liquor. A quantitative relation between the rate of delignification and the concentration of free sulphur dioxide, or better, the partial pressure of sulphur dioxide gas, has been established. The nature and significance of this relation is discussed in connection with the mechanism of the delignification process. It has been shown that the hydrogen ion concentration alone does not determine the rate of cooking, but evidence is presented that indicates that the product of the concentrations of the hydrogen and bisulphite ions is the controlling factor.The yield of pulp for any given lignin content is independent of the free sulphur dioxide over the whole concentration range, but increases in a marked manner with the concentration of the combined. An explanation is offered, and the practical aspects are pointed out.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Superconducting Wind Generators with Capacities of 10 MW and Larger

2020 ◽  
Vol 10 (10) ◽  
pp. 59-67
Author(s):  
Victor N. ANTIPOV ◽  
◽  
Andrey D. GROZOV ◽  
Anna V. IVANOVA ◽  
◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Wind Power ◽  
State Of The Art ◽  
Superconducting Materials ◽  
Commercial Application ◽  
Synchronous Generators ◽  
High Temperature Superconducting ◽  
Wind Generators ◽  
Main Factor

The overall dimensions and mass of wind power units with capacities larger than 10 MW can be improved and their cost can be decreased by developing and constructing superconducting synchronous generators. The article analyzes foreign conceptual designs of superconducting synchronous generators based on different principles: with the use of high- and low-temperature superconductivity, fully superconducting or only with a superconducting excitation system, and with the use of different materials (MgB2, Bi2223, YBCO). A high cost of superconducting materials is the main factor impeding commercial application of superconducting generators. In view of the state of the art in the technology for manufacturing superconductors and their cost, a conclusion is drawn, according to which a synchronous gearless superconducting wind generator with a capacity of 10 MW with the field winding made of a high-temperature superconducting material (MgB2, Bi-2223 or YBCO) with the «ferromagnetic stator — ferromagnetic rotor» topology, with the stator diameter equal to 7—9 m, and with the number of poles equal to 32—40 has prospects for its practical use in the nearest future.

SOMERS LTA COPPER

Alloy Digest ◽  
1980 ◽  
Vol 29 (12) ◽  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Physical Properties ◽  
Copper Foil ◽  
Heat Treating ◽  
Dielectric Substrates ◽  
Printed Circuits

Abstract SOMERS LTA Copper is a wrought copper foil that can be annealed at 350 F in 15 minutes to the full-soft condition; its use simplifies the manufacture of printed circuits (LTA = Low-Temperature Annealable). LTA Copper is especially useful for foil weights up to and including one ounce per square foot (0.0014-inch thick) for laminating to high-temperature dielectric substrates. This datasheet provides information on composition, physical properties, and elasticity as well as fatigue. It also includes information on forming, heat treating, and machining. Filing Code: Cu-407. Producer or source: Olin Corporation.

CHRO-MOW

Alloy Digest ◽  
1958 ◽  
Vol 7 (2) ◽  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Steel Company ◽  
Temperature Performance ◽  
Hot Work Steel ◽  
Crucible Steel ◽  
Red Hardness

Abstract CHRO-MOW is a tough hot work steel which will harden from a relatively low temperature in air. It possesses a desirable combination of toughness and red-hardness. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-67. Producer or source: Crucible Steel Company of America.

NICLOY 5

Alloy Digest ◽  
1960 ◽  
Vol 9 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Ferritic Steel ◽  
Heat Treating ◽  
Low Carbon ◽  
Temperature Performance

Abstract NICLOY 5 is a low carbon, nickel ferritic steel reecommended for low temperature service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-96. Producer or source: Babcock & Wilcox Company.

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