INDUSTRIAL AND ENGINEERING CHEMISTRY
August 1952 I 2(
Code X
0
Somple Decolorization (%) Areo (m*/g3
0
X
1833
a t the same rate, due t o equal rates of crystallite growth, then if one has more area than the other and t h a t area is contained in larger pores, it will, under the same conditions of use and reactivation, continue t o maintain its excess of area. Since, with proper reactivation the activity per unit area increases with cycles of use, the adsorbent with the larger area will eventually do more work than the one with smaller area. From the foregoing it is evident t h a t an adsorbent consisting principally of hydroxyapatite, whether it be t h e natural apatite of bone char or the synthetic apatite of Synthad, should not deteriorate in color- and ash-removal power once its crystallites have ceased t o grow rapidly. Thereafter, loss of area is proceeding very slowly in so far as the effect of crystallite growth is concerned. Consequently, if all the mineral matter and all the organic matter picked up by the adsorbent in a cycle of use could be eliminated before it was sent to the reburning kiln, itti area would diminish at a negligible rate from cycle to cycle. Since there is no evidence that with proper reactivation activity per unit area decreases with length of service, it follows t h a t except for attrition losses the adsorbent would last forever. The complete elimination of mineral matter still presents a problem, a solution t o which has been suggested by Deitz (4),but there is no reason why any organic residue should be allowed t o remain in the adsorbent. A properly designed reburning kiln, which allowed adequate control of :bar temperature and of the oxidizing potential of t h e gaseous environment, would make possible the maintenance of service chars at a markedly higher level of efficiency than is possible with the equipment in current use.
0
SW S W H - I SWLW SWLWH 89.7 93.1 90.1 89.8 92.7 79.3 114.0 95.5
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2
a
24 U
0
z2
a
sa
ACKNOWLEDGMENT
3
The authors wish t o thank Baugh and Sons Co. m d Mellon Institute for permission t o present this paper. Frank Wood assisted in determining the nitrogen desorption isotherms.
PORE RADIUS, r (A)
Figure 10. Effect of Contact with Granulated Sugar Liquor and of Reactivation on Cumulative Pore Area of Washed New Synthad C-38
hydroxyapatite crystallite growth in Synthad during the early cycles, the rate of production of new area by the carbonization of organic matter from the sugar liquors a t first exceeded, and then balanced, the loss of area due t o crystallite growth, but by cycle 13, the rate of production of new area no longer exceeded that of the loss of area from crystallite growth and the area began t o fall systematically. Also, by cycle 13, the rate of crystallite growth in the bone char had decreased t o about that in t,he Synthad and the two curves become nearly parallel. When two adsorbents have reached the condition of losing area
LITERATURE CITED
(I) Barrett, E. P., “Advances in Carbohydrate Chemistry,” Hudson, C. S., and Cantor, S. M., eds., Vol. 6,pp. 220, 227, New York, Academic Press, Inc., 1951. ( 2 ) Barrett, E. P., Brown, J. M., and Oleck, S. M., IND. ENG.CHEM., 43,639 (1951). (3) Barrett, E. P., and Joyner, L. G., J . Am. Chefti. SOC.,73, 373 (1951). (4) Deitz, V. R. (to United States of America), U. S. Patent 2,557,948 (June 26,1951). (5) Joyner, L.G.,Barrett, E. P., and Skold, R. E., J . Am. Chein. SOC., 73,3155 (1951). (0)Juhola, A. J., Matz, W.H., and Zabor, J. W., paper presented at the Symposium on Adsorbent Refining Aids in the Sugar Industry, 119th Meeting AM.CHEM.SOC., Boston. Mass., 1951. RECEIVED for review December 1 1 , 1951.
ACCEPTEDApril 21, 1952.
Correction In the paper “Partial Combustion of Gas with a Deficiency of Air” [F. E. Vandaveer and C . George Segeler, IND. ENG.CHEM., 37, 816-20 (1945)], the following corrections should be made. On page 817 in the second paragraph of the second column, t h e sentence starting in line 12 should read “Under the same conditions the carbon monoxide content increased from 0 t o 22%, the hydrogen content increased gradually from 0 t o 41.2%, and methane appeared in traces at 90% air and gradually increased to 4% a t 20% aeration. In Figure 4 on page 819 the hydrogen curve is incorrect in that it should be a straight line from 0% hydrogen and 100% aeration to 22% hydrogen and 20% aeration. Also, under the words
“Gas Constituent-Per Cent” at the left side of the curve the phrase “For hydrogen multiply by two“ should be added. On page 819 in the last paragraph the third sentence should be changed to read “On natural gas the ratio of carbon monoxide t o hydrogen varies from 1 to 0.53 as air is decreased from 100 t o 25%.” On page 820, in Figure 8 the curve for natural gas is incorrect, It should be a straight line extending from the point located at 1 0 0 ~ aeration o and a ratio of 1.0 downward t o a ratio of 0.53‘at 10% aeration.
F. E. VANDAVEER
