August, 1942
INDUSTRIAL A N D ENGINEERING CHEMISTRY
amount of acid used in the lower graph. The original ash content of sample 4 was too low to show comparable results with these two samples. The analyses of the rosin ash from the filtered, water-washed oleoresin and from the acid-washed oleoresin are given in Table IV.
Literature Cited Borglin, J. N. (to Hercules Powder Co ) , (May 22, 1934).
U.S. Patent 1,959,564
987
(2) Gillet, A. C., French Patent 684,873 (Nov. 14, 1929).
i:; " , ~ ; e ~ . ~ u ~ s ; (5)
(6) (7) (8) (9)
~~~~a~~~~~~~~ kM:?'0$::,3LHEM., 22, 446-8 (1930). Oliver, A. F., and Palmer, R . C. (to Newport Industries Inc.), U. S. Patent 1,881,893 (Oot. 11, 1932). Palkin, S., and Smith, W. C., Oil & Soup, 15, 12@-2 (1938). Reed, J. O., Chem. & Met. Eng., 48, No. 12, 68-70 (1941). Smith, W. C., IND. ENQ.CHEM..28, 408-13 (1936). Smith, W. C., Reed, J. O., Veitch, F. P., and Shingler, G. P., U. S. Patent 2254,785 (Sept. 2, 1941).
Effect of Air on Color of Sugar Liquors C. A. FRANKENHOFF The Dicaiite Company, New York, N. Y.
BRIEF paper' was recently published covering the advantages of filtration on pressure filters of phosphoric-acid- and lime-defecated sugar liquors as compared with Williamson type or modified type clarifiers. It was shown clearly that all types of sugar liquors could be defecated and filtered economically on pressure filters. As pointed out, this procedure was in use in sugar refineries and was entirely economical and practical, requiring only a higher capacity filter aid as compared with nondefecated sugar liquors. Phosphoric-acid- and lime-defecated washed sugar liquor was later run in another refinery, but the expected bleach was not obtained from the addition of 0.01 per cent Pz0s on solids. The bleach obtained was less than half of what was expected. The only apparent difference between the plants was that one had air agitation and the other mechanical agitation. The plant with the lowest bleach results had air agitation. To check our deductions in this situation, a series of tests was instituted in the lab0 atory on the effect of the air. The flow of air into the washed sugar Lquo was made equal to the estimated amount used for air agitation in the blowups in the refinery. The sugar liquor was maintained a t 180" F. The same sugar was used in all tests to make a 60" Brix liquor. Air was bubbled through a t the rate of 640 cc. per minute. I N T H E first series 60" Brix washed sugar liquor was heated and kept a t 180" F., with and without the addition of air:
A
&tin,of Heating 0 5 10 15
Without Air 100 102 100 101
With Air 100 103 104 108
Min. of Heating 30 45 60
Without Air
99 100 100
With Air 113 116 119
The increase in color to be removed by the char was therefore 19 per cent and was due only to the addition of air for agitation on clear prefiltered liquor. In the second series, liquor was used which had been defecated with phosphoric acid and lime and then filtered This liquor had been bleached 38 per cent with mechanical 1 Frankenhoff, c. A , , I N O . E N Q . C H E M . , 34, 742 (1942)
agitation. The agitation of the liquor with air a t 640 cc. per minute a t 180" F. brought about the same color deterioration, as the time in contact with air increased, as did the agitation of nondefecated filtered liquor. However, the liquor showed no color change when the same amount of air was bubbled through a t room temperature: Min. of
Contaot 0 5 10 15 30 45 60
-
640 Co. Air/Min.-180° F. Room temp. 62 62 63 62 64 62 66 62 67 63 70 61 73 62
No Air 180' F: 62 62
58 56
56 60 61
In one hour the color deteriorated at 180" F. by 18 per cent. Therefore about one third the bleaching effect of the phosphoric acid and lime defecation had been lost. When this liquor was heated to 180" F. with no air for the same period, the bleach was improved up to 30 minutes; a t the end of an hour, the color was substantially the same as a t the start. In order to check the effect of filter aid on this color deterioration due to air agitation, tests were run using 0.55 per cent Dicalite Special Speedflow in the same liquor a t 180" F. and room temperatures: hlin. of Contact 0 5 10 15 30 45 60
-640 Cc. .4ir/Min.-180° E". Room temp. 100 100 104 100 106 100 110 99 113 100 118 100 121 100
N o Air, Heated to 180° F 100 100 100 102 100 100 102
These data show that, as a result of air agitation a t 180" F., the color to be removed was increased as the time of contact increased. Heating to 180" F. without air or agitating with air at room temperature brought about no color deterioration. As might be expected, when carbon dioxide instead of air was used for agitation on filtered washed sugar liquor heated to 180" F. a t room temperature, the color to be removed was decreased, partially as the result of a slight drop in pH:
988
INDUSTRIAL AND ENGINEERING CHEMISTRY
Time
lSOo F.
0 5 10 15
100 99 96 96
Room Temp. 100
97 97 96
Time 30 45 60
Room Temp.
.''081 93 94 93
93 93 89
Then, instead of air, it would seem desirable to use something that would aid instead of deteriorate color. Possibly even waste gases from the boiler house could be utilized if their composition was suitable. ACCORDING to these results, companies using air agitation in the blowups or storage tanks are paying a penalty of additional cost for removing color. How much that cost is will depend upon the time and amount of air in contact with the sugar liquor and the temperature a t the time of contact, and money can be saved by changing the method of agitation from air to mechanical means. The amount of air used in conjunction with the modified Williamson clarifier undoubtedly accounts for the need for larger amounts of phosphoric acid to obtain 40 per cent bleach than are required when these defecated liquors are
Vol. 34, No. 8
handled on a pressure filter where no air agitation is used in the blowups. The work on this subject is being continued to determine the following factors: 1. Is this deterioration in color with air agitation due to further oxidation of iron salts, organic matter, or sugar? 2. Is the air oxidation taking place at the blowups due t o air agitation an aid to easier removal of color at the char? 3. Is there any loss of sugar due t o air agitation?
We believe that the effect of the air is to increase color due to further oxidation of the iron. We are not convinced that any sugar is lost due to air agitation. It seems, however, that the bad effect air agitation has on color is sufficient to justify prompt change to mechanical agitation of a suitable type. If paddle or mechanical agitation is adopted, it should be designed to give the degree of agitation required for best results from a uniform and rapid dispersion standpoint. PRESENTED before the Division of Sugar Chemistry and Technology at the 103rd Meeting of the
AXERICANCHEXICAL SOCIETY, Memphis, Tenn.
Adjustment of the pH of Sugar Solutions with Attapulgus Clay W. A. LA LANDE, JR., J. B. SANBORN, 0. T. AEPLI, AND W. S . W. MCCARTER Porocel Corporation, Philadelphia, Penna.
0 AVOID excessive losses from inversion and decomposition, it is necessary to prevent or to correct the acidity which develops a t various stages of the sugar refining process. The refiner uses lime or sodium carbonate for the purpose. The method is objectionable because ashforming constituents are added, the color of the solution is darkened, and some sucrose is lost to the final sirup (many inorganic compounds are melassigenic). I n early experiments with mineral adsorbents as sugar refining media, it was observed that Attapulgus clay invariably produced a filtrate pH of 7.0 or above, although it was inferior to bauxite and char as a refining adsorbent. The ability to raise the pH of an acid sugar solution was not possessed by other common types of argillaceous or baseexchanging minerals. Filtration through fuller's earth as a preliminary step in the processing of a sugar solution is ineffectual in ultimate pH adjustment, since a solution so treated appears to be more susceptible to pH lowering during the subsequent adsorbent refining operation than one which has not been clay-treated. But by immediately repercolating acid bauxite and char filtrates through the properly calcined earth, it is possible to produce an extraordinarily high yield of filtrate with satisfactory pH; in many cases a slight further refining action is also obtained. The purpose of this paper is to report the results of a systematic laboratory investigation of this effect.
T
Materials and Operating Technique The Georgia fuller's earth used is a hydrated magnesium aluminum silicate known commercially as Attapulgus clay. In this report it will be referred to by this term or as clay, earth, or fuller's earth. Kerr considers Attapulgus clay to be a member of the montmorillonite group (8). Lapparent (4, 6) and Bradley (1) published data to support the view that the earth is a distinct mineral species to which the former worker gave the name "attapulgite". The clay was calcined before use a t the specified temperatures for 30 minutes in a gas-fired rotary furnace. After heating under these conditions a t 900" F. Attapulgus clay has a settled volume weight of about 32 pounds per cubic foot and a volatile matter content of 3.0 per cent. For the contacting experiments, weighed quantities of the sugar solution (usually 300 grams) and adsorbent were mixed a t 165" F. and agitated a t this temperature for 10 minutes. The suspension was separated by filtration through paper. The percolation experiments were run according to the technique described in an earlier publication ( 3 ) . All filtrations were made a t 165" F. * 2". The filters were run a t a rate proportional to 12.5 ml. per minute per 1000 ml. of clay, unless otherwise specified, to a given yield or throughput or to a given pH. The filtrates were collected in measured fractions. The pH of each fraction was determined immediately (electrometrically). Progressive composite filtrates were made by combining successive fractions. In the tabulated data the throughput a t any given time is the total quantity of sugar solids, expressed as pounds of sugar solids per pound of clay, which has passed through the filter up to that time. The various sugar solutions were analyzed by standard
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