INDUSTRIAL AND ENGlNEERING CHEMISTRY
1516 24
15
0
96
VOL. 31, NO. 12
grams of triethylene glycol, the volatile acids (boiling point 146" C. a t 1-2 mm.) of a terpenemaleic anhydride adduct known as "Petrex" (169 grams), and 50 grams of maleic anhydride. One gram of the above resin was dissolved in 10 grams of styrene and treated with 0.2 per cent of benzoyl peroxide. I n 13 days a t 62" C. a hard, clear, resinous mass formed. This resin was placed in benzene, and a photographic examination made of the changes (Figure 6 ) ; swelling began in a very short time, but owing to the slow penetration of the solvent, almost 100 hours are necessary for the solvent to penetrate to the core of the material. A similar swelling phenomenon was noted by Staudinger (fI ) in the divinylbemene-styrene composition.
Conclusions 189
165
240
216
264
FIounE 6. SU ELLING
OF SrYnENE-M,~r.EIC-TEarENE-MALfilC GLYCOL POLYMEK IN HESZENE
colorations did not occur; fifty per cent solutions in various solvents were made up of a mixture of 25 per cent. methyl methacrylate and 75 per cent diethylene glycol maleate: solvent
A p ~ ~ a i a n ohfter e 3 Days st Room Tern".
The introduction of an unsaturated resinous ester of the maleate polyester type into a compound of the type R-CII= CI&has the property of curing the latter. It is thus possible to cure resinous polyesters by polymerization reactions and vary the netting index over a wide area.
Literature Cited (I) Aloksendrov, B. I., Tech, Phw. U. S. S.R., 4, 931 (1937). ( 2 ) Blaikie. K. G.. and Crozier. R. N.. IND.END.CESX.,26. 1155 (1936). (3) Bradley, T. P..Ibid., 29, 440-5, 57944 (1937). (4) Bradley, T. F.,Kropa, E. I,., and Johnaton, W. B., Ibid., 29, 1270-6 (1937). (5) Hill, K. (to Imperid Chemical Industries, Ltd.), British Patent 423,790 (Feb. 4, 1985).
Reaction with Styrene Inasmuch as the diethylene glycol maleate resin is insoluble in styrene, no direct reaction may be made to occur under ordinary conditions. However, if s maleic resin is,modified with a terpene maleic adduct, satisfactory solution may be obtained. A resin of acid KO.50 was prepared a t 180' C. from 76
(6) I. G. Farbeniaduatrie. A.-G.. Froneh Patent 786.940 (Aug. 22, 19353 Lespieiru. E., and Deluohat, Compt. rend., 190, 683 (1930). Mark, H., Nature, 142,937 (1938). Moresrr. G . T.. Meeaon. N. J. I,., and Holmes, E. L., J. Soc.
St&d&er.~n., and Sehwalbaoh, A., Inn.. 488, 8 (1931) Taylor, H. S., and Vernon, A. A., J. Am. Chern. Soc., 53, 2527 (1931).
Revivifying Bone Char A New Method and Apparatus OXE charcoal is an efficient
EDGAR WHITM)W RICE claimed for decolorizing carbons. suhstancefortliercmovnlof suge- T2afim:r,, pII...I This cost difference might be A.-y...az6 uv.ypany, Yonkers, N. Y. caramel color from suear c h a n g e d , p r o v i d e d a cheaper solutions, and i t bas the added method of production of a satisadvantage of absorbing considerable quantities of minfactory decoloriziiig carbon could be worked out; therefore i t eral matter. Ilowever, it is much less efficient in absorbing seemed logical to investigate possible improvements in hancolor than an equal weight of some types of decolorizing cardling bone charcoal. The present methods are over thirty bons. This holds true cven when comparisons are based upon years old, and one could reasonably expect the possibility of the relative weights of cmbou in each. This latter fact sugimprovement in any process niter sucb a lapse of time. gested the possible improvement of the decolorizing effect of Chemical annlyses hsve indicated that the so-called carbon bone charcoal through changing the character of the carbonacontained in bone charcoal is but 60 per cent actual carbon, ceous portion. It seemed possible that it might attain many whereas in decolorizing carbons i t is practically 100 per cent. times its present adsorptive power for sugar color and still Therefore, if some method could be devised t o change the retain the ash-absorbing qualities. character of the "carbon" in bone char considerably, it might Sugar production costs favor bone charcoal for sizable inbe possible to accomplish the desired effect. stallations, principally because of the small losses in weight upon reactivation as compared with the large losses during RAY ( 1 ) , quoting Chaney, stated that selective oxidation by reactivation of drcolorizing carbons. This Loss in material is means of air was very efficient in producing activated carbons n deciding factor and of greater importance than the savings if the operation could he thoroughly controlled, nnd this led in the cost of equipment and operation which are geiierally the author to the conclusion thnt oxygen diluted s i t h con-
B
.
DECEMBER, 1939
INDUSTRIAL AND ENGINEERING CHEMISTRY
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siderable amounts of inert gases and recirculated during the activating period might bring about the desired result. Since this must be done as cheaply as possible and while the char is hot, flue gases were tried first. A preliminary investigation was started to determine what effect such treatment might have upon bone char; it was found that carbon dioxide decidedly improved the efficiency, and that steam had no influence a t such temperatures as were contemplated. Ray (I) had shown that active carbon adsorbs partially burned material which reduces its activity. Consequently, if careful burn7 ing could be carried out, bone char should APPARATUSFOR REACTIVATING BONE gradually improve. Experiments showed that CHARCOAL burning off considerable carbon a t one time did not have a lasting benefit and eventually that it was detrimental; therefore, it seemed necesA . Revolvjng iron drum with customary supporting and driving units; it contains flights t o raise and shower the bone charcoal sary to devise an exactly controlled equipment B . Blower which could be set to take care of differing bone C. Combustion chamber D . Damper chars but would be different from the present E . Source of heat F . Gas chamber and dust catcher kilns where the same reactivating treatment is G. Flue t o stack applied regardless of the actual work which has H . Feedspout I . Feeding device made from a pulley b y cutting away a few inches of the fape and insertbeen done by the bone char. It was evident ing a pocket which measures a portlon of bone charcoal a t each revolution J . Duct from blower t o air lift that the amount of air present must be suffiK. Chute for reactivated material cient to burn the desired amount of material, L. Thermocouple M . Lift pipe for carrying bone charcoal u p t o expansion chamber and it had to be so arranged that small amounts N . Return duct for gases from expansion chamber 0 Adjustable sleeve of air could be thoroughly distributed through P : Hopper, kept full of reactivated material large amounts of bone charcoal. &. Slots t o allow char to flow into air lift R . Duct for returning gases Sulfur has generally been considered very S. Dam t o retain material in the drum T. Lever t o set sleeve 0 harmful in bone char sugar refining, but this is U. Inlet for fresh air or gases from second stage of air lift, if such is used probably true only when it occurs in the form V. Chute bringing wet char t o I of a sulfide. It seemed reasonable to expect that the reauired atmomhere would not Droof outgoing treated material. The upper end was enclosed duce sulfides as a final pioduct, and if t h e sulfur was burned within a brick chamber having a flue leading to a stack and a to sulfate, little harm could result because individual bone large duct leading to a sizable fan. A mixture of air and part chars have a definite characteristic adsorptive capacity for of the gases delivered by this fan were used to cool the reacsulfates and they cannot be loaded with greater amounts. tivated char and to elevate it to a settling chamber. From It is common for sulfur compounds in raw sugar to pass the chamber the gases were led back to the combustion annularly through a bone char filter to an amount many times chamber and were recirculated through the drum. A damper that permanently retained by the bone char. controlled the amount of outside air and another damper the The so-called Weinrich decarbonizer, an externally fired amount of recirculation, so that the quantity of excess air revolving drum for reactivating bone char, had proved efficould be carefully regulated and a constant recirculation of cient in practice if the proper admission of air to the hot bone gases maintained through the drum. char could be controlled, but control is not satisfactory in any It is necessary to provide for recirculation through the of the units which have been observed by the author. There drum; otherwise the damp char will work down the drum seemed to be great possibilities in a new type of equipment. almost to the discharge point before the heat from the fuel Experiments with an apparatus of a new design brought begins to have any beneficial effect. Apparently the water about reactivation easily; after as little as 10 minutes treatpresent first becomes steam which is adsorbed by the char, ing time, the resulting bone char equaled that from the ordiand considerable laving with the hot flue gases is required nary type of kiln. before any oxygen can come in contact with the inner surExperiments proved that the hot products of combustion faces which must be reactivated. It was found that if recircufrom illuminating gas when burned with controlled amounts lation of gases is employed, lower temperatures are required of air, as they came in contact with the char could be made to for proper reactivation. reactivate satisfactorily. It was decided t h a t this fuel was The results from the first experiments with this new type of too expensive for plant operation in the New York area, and kiln were satisfactory as far as the reactivation was concerned, oil was chosen for a' large-scale trial. The gases were to be but it was found that more time and heat were necessary to passed through a rotating drum with internal flights to raise treat damp char received directly from the washing process and scatter the bone char into the stream of gases. Possible than had been required when dry char was used in laboratory loss from attrition was discounted by an experiment in which experiments, and the treating time had to be increased from char was tumbled in a 5-pint bottle continuously for 2 months 10 to 30 minutes and the temperature from 400" to 700' F. without creating sufficient dust to weigh. It was also found that with a carefully controlled temperature considerable excess air could be used; this dispelled the A SATISFACTORY scale plant (9) was then constructed previous supposition that a partially reducing atmosphere with a capacity to treat 2 tons per hour. It consisted of a might be required. It became necessary to reduce the slope rotating drum, 4 feet in diameter and 35 feet long, with a fireof the drum almost to the horizontal and to put a dam a t the brick combustion chamber a t the lower end. The temperadischarge end as used in the Weinrich kiln in order to retain ture was controlled by a thermocouple located in the stream
1518
INDUSTRIAL AND ENGINEERING CHEMISTRY
the char for a sufficient length of time. By control of recirculation the gases to the stack could be brought down to any desired temperature due to the cooling action of the damp char as it entered the drum, and the stack temperature could easily be held down t o 140’ F. with very little heat loss. The use of an air lift for bone char has been the only method used in Australian refineries for many years. Laboratory experiments in blowing char through glass tubes showed no abrasion if vertical pipes were used, but the least bend caused rapid abrasion both of the pipe and the char. Raising the char tn the desired height can best be accomplished in two steps wherel)y the char can be cooled to any desired temperature and all the heat returned to the combustion chamber.
THE fuel used was so-called furnace oil, which cost at that time about 7.8 cents per gallon. Fuel costs were found to be the same per pound of char treated in this internally fired kiln as they were in the norrnal type of kiln in which buckwheat coal was burned. If other cheaper fuel was used, either crude oil or natural gas, the fuel saving would be considerable; and since the control [ i f temperature proved not to be as critical as was at first supposed, an ordinary type of burner with simple control apparatus could be satisfactorily used. It was found easy to hook the various units of the apparatus together in such a fashion that if the fire went out or any single step was interrupted for any reason, all the units stopped. This worked very well and merely required that some one should determine what was wrong and again start the units in proper sequence. No continual attention was needed and the labor cost was consequently small.
VOL. 31, NO. 12
The initial cost of this improved kiln with all its accessories was ahout equal to the average cost of upkeep for 2 years of two ordinary retort kilns which together have an equal capacity. This indicates a greatly reduced overhead cost for this department. The space required was one floor in height with a small hopper beneath the floor level to receive the reactivated char and discharge it in turn into the bottom of the air-lift tube. Three floors are required for the ordinary vertical retort kiln with the necessary dryer above and cooler pipes below. The plant-scale unit was operated intermittently for a year and a half on low-grade char. A mass of operating data and many analyses were made of the char before and after treatment, as well as many comparative tests to ’indicate variations in the decolorizing ability of the char compared with that produced in the usual type of kiln and in the Weinrich apparatus. In no case were variations in results from the different methods of treatment greater than differences in day-to-day samples of material from any one method of treatment. It was not possible to segregate the treated char at that time, and the whole factory was dismantled before experiments could be made on new char. It is unfortunate that the work was terminated, but the process is not so radically different that one could expect abnormal results in a short period of time. The prospective large savings in operating and overhead costs make the possible use of the process attractive.
Literature Cited (1) Rav, A. B., Chem. & Met. Eng., 28, 977 (1923). (2) Rice, E. W., U. S. Patent 1,758,202 (May 13, 1930).
SORBOSE FROM SORBITOL Semiplant-Scale Production by Acetobacter suboxvdans J
P. A. WELLS, L. B. LOCKWOOD, J. J. STUBBS,AND E. T. ROE U.S. Department of Agriculture, Washington, D. C.
I
N A PREVIOUS communication ( 3 ) studies on I-sorbose production from sorbitol by submerged growths of Acetobacter suboxydans were described. Rotary drum fermenters were employed as culture vessels, since in a n earlier study of a similar oxidative fermentation process this type of equipment had proved to be satisfactory in providing the necessary conditions of agitation and aeration ( 2 ) . A consideration of the various factors involved in adapting the laboratory-scale sorbose process to pilot-plant scale suggested the desirability of further study. The object was to simplify the procedure and to effect certain economies of operation which, although of relativdy minor consideration in the laboratory, would be of importance for commercial use of the process. This paper reports the use of concentrated corn steep liquor as a nutrient material for the fermentation, a simplified method for large-scale inoculum preparation, further results on the effeck of sorbitol concen-
N. PORGES AND E. A. GASTROCK U. S. Agricultural By-products Laboratory, Iowa State College, Ames, Iowa
tration, and the adaptation of the process to semiplant-scale operation.
Materials and Methods (1) LABORATORY-SCALE EXPERIMENTS.The equipment, methods of analysis, materials employed, organism and culture methods were, in general, the same as those previously described ( 3 ) . Ten per cent sorbitol solutions were used in all cases
unless stated otherwise. In experiments requiring small rotary fermenters, an air flow of 375 cc. per minute er liter of solut.ion, an air pressure of 30 pounds per square incff (2.11 kg per sq. cm.), a temperature of 30’ C., and a rotation rate of 13 r. p. m. were used sinre these conditions were found in the earlier work t o be most satisfactory for sorbose production. T h e concentrated corn steep liquor employed as a nutrient substitute for dried yeast extract was obtained from the A. E. Staley Manufacturing Company, and was known as “Yeast Compound”. Analysis supplied by the manufacturer showed that this product contains on the average 55-60 per cent solids, of which the protein content is 45 per cent, mineral matter, 18
