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.

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.

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.

scholarly journals Diurnal vertical migration of some cladocerans in relation to the physico-chemical factors in a fish pond

1970 ◽  
Vol 20 (2) ◽  
pp. 147-154 ◽  
Author(s):  
AS Bhuiyan ◽  
S Akhter ◽  
MMA Quddus
Keyword(s):  
Key Words ◽  
Vertical Migration ◽  
Fish Pond ◽  
Chemical Parameters ◽  
Surface Layers ◽  
Diurnal Vertical Migration ◽  
Physico Chemical ◽  
Chemical Factors ◽  
Diurnal Movement ◽  
The Relationship

Diurnal vertical migration of four genera of cladocerans, namely Diaphanosoma sp., Daphnia sp., Moina sp. and Bosmina sp., during March to December, 2007 showed that the number of Diaphanosoma sp. was 501 units/1 in the surface layers, 172 units/l in the middle layers and 190 units/l in the bottom layers. The yearly number of Daphnia sp. in surface, middle and bottom layerss was 362 units/l, 46 units/l and 189 units/l respectively. In surface, bottom and middle layers, the number of Moina sp. was 159, 71 and 32 units/l, respectively. Bosmina sp. was 78 units/l in surface, 31 units/l in the middle and 33 units/l in the bottom layers. The number of Diaphanosoma sp., Daphnia sp., Moina sp., Bosmina sp., were 455, 149, 259 and 358 units/l, respectively in the morning, 63, 176, 142, 43 units/l at noon and 107, 55, 28, 59 units/l, respectively in the evening. Throughout the study period the cladocerans were always abundant near the surface during morning and evening. Among the factors responsible for the diurnal movement of cadoceran, light played the most important factor. The relationship between the physico-chemical factors and the cladoceran occurrence in the pond was also explored. Key words: Cladocera; Diurnal migration; Physico-chemical parameters; Fish pond DOI: http://dx.doi.org/10.3329/dujbs.v20i2.8975 DUJBS 2011; 20(2): 147-154

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