904
INDUSTRIAL AND ENGINEERING CHEMISTRY
for further purification. Treating the rectified alcohol with 0.2 ml. of potassium permanganate per 100 ml. of alcohol, and distilling gave a product that remained pink for 30 minutes when 10 ml. of alcohol were tested with 1 ml. of 0.170 potassium permanganate according to Army Specification F-41. This material easily meets specifications which require that tjhe color remain for 20 minutes. CONCLUSION
Breiver's yeast S . cereuisiae, h-o, 49, University of \\'isconsin collection, was propagated on 1% wood sugar and gave yeast yields of 16 to 2gr; in 14 to 18 hours with a 2 to 1 ratio of air t o liquid. Yeast produced on wood sugar solutions converted sugar into ethanol. When 2y0 of yeast by dry n-eight fermentation was complete in 5.5 hours, whereas 0.5% yeast required 24 hours. Continuous transfer of yeast from an 18- to 20-hour fermentation to fresh 5y0 sugar solution was continued through as many as fift,y-nine transfers without loss of alcohol yield and without. contamination from bacteria or other yeast. The addition to the fermentation of 0.02570 of Louisiana second-crop molasses increased the rate of fermentation but did not affect the yield (after correction was made for molasses) when transfers were made after 18t o 20 hours. The use of wood sugar solutions, clarified by the addition of aluminum sulfate or solutions prepared under operating conditions which produced less tar, improved the rate of yeast growth. Yeast growth during fermentation was sufficient to overcome R loss of about 20y0 during each transfer. Alcohol yields in six series of continuous transfers ranged from 39.2 to 40% of the total sugar, and from 47.0 to 47.9% of the fermented sugar. When 5y0solutions were used, yields of 95% alcohol yields were 2.64 gallons per 100 gallons of hydrolyzate, and 64.5 gallons per ton of dry bark-free wood. Large samples of the fermented sugar solutions were distilled in pilot plant equipment. The alcohol produced was of high quality. Quantities of heads and fusel oil were unusually low.
Vol. 38, No. 9
ACKNOWLEDGMENT
On behalf of the Forest Products Laboratory the authors Jvi,*h to express their appreciation t o thv Office of Production RP search and Developmelit- of the \ V u Production Board, and t,o Vulcan Copper & Supply Compa,ny for supplying a portion of the funds required for this study. Acknowledgment also is made to the follorving members of the Forest Products Laboratory staff: Reid H. Leonard and Hugh Fetty for assistance in the fermentation experiments, and Janet L. Bubl, Mary N. Mitchell, and 81bert A. Kline for assistance in making the many analytical detcrniinatioris involved. Valuable assistance in carrying out, tht. pilot plant distillations was given by Ray Katzen and other members of the staff of the Vulcan Copper & Supply Company. Valuable counsel was also received from Edward G. Locke of the Pacific Sorthwest Forest Experiment Station, and from W. H. Peterson and hfarvin ,Johnson of the University of Wisconsin. LITERATURE CITED (1) E'oiest Products Lab., Rept. R1475 (March, 1945).
(2) Grondal, B., and Berger, H. W., Chsm. & M e t . Eng., 52, 6 (1945\. (3) Harris, E. E., Beglinger, E., Hajny, G. J., and Sherrard, E. C , ISD. ENG.CHEY.,37, 12 (1945). (4) Heuser, E., Cellulosechem., 1, 41 (1920). (5) Leonard, R. H., and Hajny, G. J.. ISD. ENO.CHEM.,37, 390 (1945). (6) Peterson, IT. H., dncll, J. F.. and Frarier, W. C.,Ibid., 37, 30 (1945). (7) Saernan, J. F.,Haiiij, E. E., and Kline, A., IXD. ENG.CHEM.. ANAL.E D . ,17,95 (1945). (8) Scholler, H., and iissociateu, U. 9. Patents 2,083,347 (June .S, 19371, 2,083,348, (June 8, 19371, 2,188,192 (Jan. 23, 1940:. 2,188,193 (Jan. 23, 1940). (9) Sjolander, Ii. O., Langlykke, A. F., and Peterson, W,H., IND. F:.VG. C H E M . . 30, 1251 (1938).
APParent Specific Gravity of Refined Sugar T
HE apparent, specific gravity or weight pef' cubic foot 01 refined sugar is B routine determination in many refineries. The procedure has not been standardized, nor have comparative tests been studied so far as can be learned from the literaturt.. The results are of value as indicating the space that a given weight of sugar will occupy in a parkage. Also there appears t,o be some relation between this figure and the quality of sugar, or :tt' least the character of the pan boiling. The met,hod adopt,ed by this l a b o d o r y was developed after discussion with Marvin D. Scott, of the Chalmette Refinery. The apparatus (Figure 1) consists of a metal funnel 7 inches in diameter and 7 inches on the vertical axis with a slope of 6 7 l / ; '. To this funnel is attached a brass nozzle with a machined aperture 6 / * inch in diameter closed by means of a small shear gate. The funnel stands on three firm legs so that, the hright is fixed. Dimensions and slope must, he exact to insure reproduriblc results with different funnels. A tared 1000-cc. Erlenmeyer flask with ll/a-inch mouth i? calibrated by filling to the brim with water a t 20" C. and weighing. The flask is then emptied and dried. Sufficient sugar to more than fill the flask is put in the funnel, the flask placed under t,he a,pert,ure, and the shear gate opened. After the funnel emp-
ties, t h e Husk k st nick 1t:veI Lvitl.1 ii spatula, the shear gate c l o d . tho sugar in the flask returned to the funnel, and the operation repeated. The stwind operation invariably fills t'he flask slightly more than full axid the level is again struck with a spatula. During the entire operation care must be taken not to jar or shake the flask or funnel. After the flask has been filled the second time, it. is weighed arid the w i g h t per cubic foot is calculated as follows:
hugar _ _of __ ~ iu flask = apparent specific gravity
wt.
w t . 01' wati'r in flapk
\r.hcr or weight per c-irbic- foot of refined sugars is of practical *slue as indicating the &pace that a Kiten weight of sugar will occupj in a package. \Ian> refineries mahe the determination but the procedure has not been standardized. A aimple apparatuv and inet hod are described, and results are readilj reproducible. Te+tson sugars of different grain size are discussed. Indications are that crjstal structure, particularly the presence of conglomerates, has a marked effect, but many unexpected results are gi\en which show the need for further study. The method is applicable t o other granular substances-for example, bone black, the weight per cubic foot of w hich is of great practical importance in sugar refining. SHEAR GATE
i,’
Ivhat smaller grain than medium coarse, gives tcists iiruund 51.5 pounds. On the o t h r r hand, “fruit-granulated” (the very fine
I
crystals collected from the granulator fans-also called “superfine” and “dessert” sugar) also s h o w a weight higher than ordinary granulated, averaging nearly 52 pounds. Some samples of fruit-granulated sho\ved low results, 49 pounds or slightly less. probably because of crystal structure. \Then ordinary fine-granulated is separated by fractional screening into different grists, a different result is obtained from what might he expected from the above figures, since the weight per cubic foot varies inversely with the size of the grain. The. following are typical results:
\
’
/--c------------+t-.,
__
---I-
’
Figirre 1.
I
Original On 28 nresb On 35 mesh On 48 mesh Through 48 mesh
--
-- --_--.-- -- .-. ------= ___I_I Apparatus for Determining Apparent Specific Gravity of Refined Sugar
In general ordinary granulated sugars (designated “standard fine” or “extra fine”) show a weight per cubic foot of about 50 pounds by this method, although some results have ranged as high as 51.4 and others as low as 48.0 pounds. Sugars made i’rom certain raws tend t o weigh heavier than others, and some rinespected results have been encountered. For example, it is .ivell known that, in packaging, a warm sugar occupies more space tli:rn the same sugar after it has cnoled. Hon-cver, tests made by riiis method on warm sugar invari;ibly givc results about 0.4 to O.;i poiind higher than the same sugar aftcr cooling under ordinary atmospheric conditions. I t h:ts becn proved that, t h i ~ :rtiomnlous result is caused by tht, ahsoi,ption of a slight amuunt o f moisture during cooling nhich interferes with the flow of sugar. 8ng:trz coolPd in a desiccator give higher w i g h t s per cubic foot thaii they do when tested warm. One refiner reports that rcfined >ug:ir stored in bins under atmospheric conditions shows a de(wase in weight per cubic foot t o an estcnt that seriously hampcw Iiiickaging, and that this is corrccittd hg circu1:iting dry x i i , tlrroiigh thc sugar in the bins. Attc~iiptrto cnrrchte tlic rwults htltn wn $izi, of grniir :i~id \\ I,iglit per cubic foot h:wc also hrought out some unexpected x.twlts,. It might he espected that :I l q p - g r a i n sugar by this teart nwuld \wig11 less per cubic foot than a small-grain sugar hev:iiise of the better packing of thc smaller grain. However, thr wsults of tests on the special gradcs of sugar designated “medium voarse”, “manufacturers”, and “sunding” show that these large cxvcm-grain "specialties" weigh more by this test than does fineglnnulnted. The medium coarse givw w i g h t s ranging as high s screened 14 pounds per cubic fdot ; sariding s u g ~ r (accurately bc*tnrr.n 18 and 26 mesh) shon- weights of 52 to 53 pounds, and ni:iriufarturws graiirilated, wliirh is 2 mort irregular and some-
W t . , Lb./Cu. 50.7 45.3 47.6 50.0 52.2
Ft.
56
of Origiilu;
100
8.0
25.0 33.0 34.0
Thc light weight of the larger grains in this mixed granulated sugar seems, from microscopic examination, to he due to the conglomerates. .I study x v a ~n i n d e of an srtificiill mixture of mcdium coarse, manufacturers, sanding, and fruit sugars to determine whcther a mised sugar norm:illy weighs lighter or heavier than the awrage of its componrmts. The following are typical figures: LIedium coarse llanufacturers Sanding Fruit sugar SIixture, equal parts by wt.
Wt., Lb./Cu. ;3.5
Ft.
01.8 53.0
49.3
56.0
Ht:re the fine sugar undoubtedly fills the voids between the larger grains to give a heavier mixture than the component p:trts. It is txidrrit from the figures cited that, further study of the rolation 1wtwec:n grain size and m i g h t per cubic foot is indicated. An iiitcrcsting side light on this subject is that, in many of‘ the iildcr tditions of handbooks generally found in engineering offices, tht, weight prr cubic foot of sugar is given as 100 pounds. Kidder’s Architcctural Handbook [17th edition, page. 1508 in point, and other handbooks have becn reported erroneous figure that was untiouhtedly derived hy multiplying the true specific gravity of sucrosc, 1.61, by the \vcsight per cubic foot of water and thus disregarding thc voids. Possibly many storage biiiw and warehouses for raw arid refinc,ci wgar have hwn constructed n-ith this errnneous figure as ii hasip lor i~aliwl:iti(ins, ACKNOWLEDGMENT
1liutiks arc: due Philip J. Vedros, Colonial Srtg~traC h n i p a ~ ~ y . !‘or :tiialytical work done in connPction with this study, and r.
;CIarviii D. Scott, of the Chalmette Refinery, S e w Orleans, La. Prtt;sb;vTm before the Divisiorl of Susar Chemistry and Technology a t the 109th >I?cting of tile . - i v E : R I C h S CHI:\IIC.4L. socIE:1.Y, . - i t l H l l t i C C i t y ,
