INDUSTRIAL AKD ENGINEERIXG CHE1IISTHI
J L S E , 193.5
-1method i h demibed for calculating the equilibrium vapor pressure curve and operating curve for the three-component >pteiiiin the regenerat’or. By means of these curves the number of theoretical plates required for regeneration map be found, or the mean driving force for the diffusional process. While the quantity of steam required for the regeneration depends greatly on the concentration of the sulfur dioxide in the feed, it cannot be materially reduced by increasing the height of the regenerat’or over eight or ten t’lieoretical plates. Diagrams are given by which the quantity of steam may be estimated for different absorption temperatures and concentrations of sulfur dioxide in the original dilute gas when the process is used for the recovery of the sulfur dioxide from such gases. For a solution 90 per cent saturated in respect to a 0.4 per cent gas a t 3.5’ C.. the quantity of steam required is approximately 4 pounds per pound of sulfur dioxide. when the regeneration is at 90” (’. The operation of a coluniii of the filled column type is described. It was found that the H.E.T. P. varies considerably with t.he composition of the feed to the column but the valueb of Koa for one vapor 7-elocity are approxiniately constant and over a limited range vary with the velocity. Further data on packing and other types of regenerators are being obtained and will he reported later. Nomenclature S = concn. of sulfur dioxide in soln., moles/100 moles water (,’ = concn. of ammonia in soln., moles/100 moles water I = mole fraction of sulfur dioxide in soln.
66.5
mole fraction of ammonia in soln. mole fraction of water in soln. mole fraction of sulfur dioxide in vapor phase mole fraction of ammonia in vapor phase mole fraction of n-atw in vapor phase
P, = T = J-
F = L = P =
rv
=
R =
H. E. T. P.= Koa =
empirical constants in equilihriurn vapor-pressure equntions partial pressure of romponent indicated hy subscript, mm. vapor prePsure of pure \rater. nini. abs. temp. moles of vapor per unit time moles of feed soln. per unit time moles of soln. leaving regenerator moles of product (pure sulfur dioxide) per unit time moles of waste per unit time moles of reflux per unit time height equivalent to one theoretical plate absorption coefficient, Ib./min./cu. ft. ,’mm. difference in vapor pressure
Literature Cited (1) Brown, Souders, and Nyland, ISD. ESG. CHEXI., 24, 522 (1932). ( 2 ) Clark and K r a s e , Ibid., 19, 205 (1927). ( 3 ) Johnstone, Ibid., 27, 587 (1935). ( 4 ) Shern-ood and Gilliland, Ibid., 26, 1093 (1934). RECEIVEDFebruary 4, 1935. Presented as part of the Symposium on I l k tillation held under t h e auspices of t h e Dirision of Industrial and Engineering Chemistry of t h e American Chemiral Society a t the Massarhusetts Institute of Technology, Cambridge, Mass.. December 28 and 29. 1934 This paper contains part of t h e results of a codperative research, Projert No. 34, with t h e Utilities Research Commission, In?., entitled “ A Study of Stack Gaees.” It is published by permission of the Director, University [ i f Illinois Engineering Experiment Station.
Dispersion of Metallic Soaps in Fatty Acids d
C. J. BONER Battciifeld Grease & Oil Corporation. Kansas Cit), 3fo.
EM
ETALLIC soaps may, according to the findings of numerous investigat’ors, be kept in solution or suspension by keeping the solution highly acid. Ruemele (7) states: “ILL the case 07 well-bodied oil varnishes, aluminum stearate of high acidity is recommended. Further in lacquer, clear lacquers are obtained only with aluminum stearate of low ash content.” Elm ( 2 ) makes the following statement: “Flocculation and coagulation cause some drier chemists to resort to the use of solubilizing agents, mostly of an acidic nature.” The following v-as noted in a trade bulletin (6): “Some difficulty has been experienced with solutions of cobalt and manganese driers. However, good results have been obtained by adding about 10 per cent of linseed oil fatty acids or 2 per cent of benzoic acid to the drier solution.” Gardner (3) in speaking of granulation in ready-mixed paints due to particles of metallic soaps sayi: “On the other hand, great quantities of free fatty acids or resin acids may prevent the formation of granules, in that they disperse them or hold them permanently in solution, thus preventing precipitation of the soaps.” +Ipprtrently only one cherniqt has experimented along the
line covered by this paper. Baldwin (1) dispersed a series of metallic soaps in oleic acid. No detail was given as to composition of the soaps. Correction was made for the free fatty acids in the soaps when freezing points were taken of the mixtures. From the freezing points, Baldwin concluded that colloidal dispersion and not true solution of the metallic soaps resulted.
Dispersion Experiments The following work was done entirely with commercial materials, eliminating as many factors as possible which might prevent accurate conclusions. I n choosing fatty acids, types were not taken from any strictly drying oils, so that they would be stable on prolonged heating. Therefore, the following acids were used : oleic, tallow, cottonseed, coconut, and abietic. The acids were saponified with potash and the soap was decomposed. After separation, the fatty acids were boiled with dilute mineral acids, washed thoroughly, and dried. Ash was taken on all acids as a check that they were free from soaps. This gave fatty acids of the following titer; oleic 11.01, tallow 36.07, cottonseed 35.10, coconut 22.63. The abietic acid was a commercial product and was checked only as to freedom from moisture and ash. I t had a melting point of 205” F. The soaps used were aluminum stearate, calcium stearate, magnesium stearate, lead naphthenate, and aluminum oleate. All commercial metallic soaps are a p t to contain the following impurities: moisture, inorganic salts, free fatty
