HYDRATE DEXTROSE W. B. NEWKIRK Corn Products Refining Company, Argo, Ill. pered. The process of temperFTER the problems in conA flow sheet and pertinent information ing consists of treating the nection with the manuconcerning the production of high-purity burned bone black in the filter facture of a high-purity hydrate dextrose are given. with a hot dilute solution of hyanhydrous dextrose had been The process in general is the production drochloric acid. After the temsolved,l efforts were turned of a raw sugar. The raw sugar is melted pering, the bone black is washed toward the production of a free from the acid with hot water, and refined over bone black. The process of superior hydrate dextrose suitand the hot water is blown out able for a rapidly growing drug refining to obtain the maximum bone black before the liquor to be treated is trade. This product could also efficiency in the combined process, includadded. The first liquors through be sold to particular customers ing raws and refined dextrose, is given. the bone black are sent to the a t normal sugar prices. A deMany developments in the construction of melt tank. The purpose of this scription is given here of the techtreatment is to remove the calnical improvements and of the equipment of corrosion-resistant metals is cium oxide from the burned bone. steps in this manufacture as discussed. Conditions leading to specks The corn sugar liquors are on the finally developed. of foreign matter in sugar are discussed and acid side and are about 5 pH. The culmination of the work solutions given. These acid liquors would take up was the building of a refined calcium from the alkaline bone cerelose house in the plant a t black and a t the same time become partially neutralized. Pekin, Ill. The process-follows, in general, that used to proThe lime salts in these liquors are detrimental because duce refined cane sugar; that is, raw sugars are produced, they assist in the formation of gypsum haze and are harmful melted, and r e h e d . Figure 1 is the flow sheet of the process. to colors, the dextrose reacting with the lime to form a whole T H E operation starts with the melt which contains about series of highly colored compounds. The neutralization of 97 to 99 per cent dextrose on dry substance. The sugar is the liquors is also detrimental. Any liquors above 5 pH have melted to 30-31 BB. with sweet waters of this same channel a tendency to decompose rapidly and give all the products and flows over fresh bone char which has been properly temof the reaction of dextrose in alkalies. All equipment encountered after filtration through the 1 IND.ENQ.CHIM.,28, 760 (1936).
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STORAGE TjNIKS
FIGURE1. FLOW SHEETOF H Y D R A T DEXTROSE ~ MANUFACTURE BY REMELTPROCESS 18
bone black is made of either nonferrous alloys or corrosion-resistant ferrous alloys. The bone black liquor is delivered to a brass Sperry press dressed with paper in order to remove any bone black haze or dust which may have passed the filters. The paper-filtered liquor is delivered into the pan supply tank feeding a finishing pan made of Everdur. The pan is boiled blank to about 39" BB. and delivered to the cooler. The older batch coolers are replaced by a heat exchanger with copper alloy in contact with the liquors and of such capacity that it is cooled from the pan temperature to 120" F. as fast as it can be pumped from the finishing pan. The cooler temperatures are controlled by a thermostat. After being cooled to 120" F., the liquor is charged on to 30 per cent of a previously cured batch to be used as foots. All of the crystallizers on this white sugar are completely lined with Everdur metal. The Everdur was welded to the steel in small sheets and spot-welded in between the welding seams. After welding, the shell was tapped and the lining tested under pressure for leaks in the welding. The cooling jacket on these crystallizers are in three sections to reduce the action of channeling on the cooling water. The crystallizers are also equipped with a cooling coil built according to the Kilby design, which is an elliptical coil with a shaft through one of the focuses of the ellipse. The agitator arms are clad with nonferrous metals. The spouts delivering the crystallizers to the mixer box are made of Everdur. The mixer box is lined with Everdur, and the mixing paddles and shaft are covered with nonferrous material. T H E centrifugal machines are water-driven. The water drive was preferred because of its lower maintenance cost, over-all efficiency, and flexibility as compared with either mechanical or individual electrical drive. The machines are designed to take advantage of some of the newer developments in centrifugal operation. The water pressure has been stepped up to 250 pounds per square inch in equipment capable of handling 500 pounds pressure. The baskets are now driven a t 1,350 r. p. m. and are designed to take care of a 6-inch load of sugar. The drive on the mixer and conveyors has been changed to individual motor drive with speed reducers; the open-type conventional drive, which is a dirt producer, is thus eliminated. The conveyor boxes and flights delivering the white sugar from the machines to the dryers are made of Everdur metal. The centrifugal machines are set on a high mounting so that the conveyors and troughs can be
(Reading from top to bottom)
ATTRITION OR Fuss MILLS Two close-set plates with projecting teeth revolve in opposite directions and thus crack or tear the corn to pieces without injury to the germ
BUHRMILLSWEERE Two LARGESTONES REVOLVE OVER EACH OTHER HUMMERSCREENING EQUIPMENT BOTTOMOF HOPPER
TEE
STORINGAND BLENDING
The handwheels permit the regulation of blending operation
20
raised high enough from the floors to give ample room for house cleaning. The sugar is spouted from the centrifugal to the conveyor in a completely enclosed spout, and the conveyors are covered. This removes one of the greatest hazards for dirty sugar. The liquor spout from the casing contains a seal trap to prevent a mist of sugar-laden air from being blown into the room; this mist would cause sticky equipment and be a source of dirt. The wash equipment on the machines is the Hepworth washer with an automatic gutter trip to route the greens and wash water properly. The white sugar is delivered to dryers made of stainless-steel-clad metal with lifting plates and plate supports of stainless steel welded to the shell. This does away with any chance that rivets may become loose or that rust may stain the sugar. Bronze centrifugal pumps are used throughout on all light liquors, and bronze Kinny pumps with herring-bone rotors are used on heavy liquor. Thedryers are equipped with air filters to prevent any dust from entering with the drying air. The dryers work in tgndem, with the air flow parallel in both, The second-pass air, after passing through a cyclone, goes to the first pass which acts as a dust collector. The dried sugar is blown with filtered air to a separate screening and blending building where the sugar is blended to ensure a uniform product in the package, both as to screen size and quality. The blended sugar is discharged into stainless-steel-clad hoppers sufficiently large to hold a day's production; all the packing can thus be done on the day shift to ensure proper light conditions for maintaining the standard quality of the product. The sugar is reblended and screened direct to the packing hoppers. THE air from the transporting system is sent to Sly separators. There is a dust-collecting system in the receiving and packing rooms. This dust is collected by a wet system. The light liquor goes from here to the melt tank to dissolve the melt. The wash water from this white system is also delivered to the melt tank and thereby returns within the system. The greens of 90 to 88 purity are mixed with the incoming starch-converted raw sugar. This raw channel starts with the converter where a 10" to 12' BB.starch is converted with hydrochloric acid to an apparent purity of 90 to 91. The converted material is delivered to neutralizer tubs, neutralized to a pH of 4.8, and delivered to large fat-separating centrifugals.
(Reading from top to bottom)
WORKINGPLATFORM OF ONE OF TERIES OF
THE BATHYDRAULIC CENTRIFUGALS
SUGARFILTERS
Two Rows OF CRYSTALLIZERS SUGAR DRYER 21
22
INDUSTRIAL AND ENGINEERING CHEMISTRY
VOL. 31, NO. 1
VIEW OF THE CENTRIF-
SHOWING
UGAL FLOOR THE ABSENCE OFBELTS BY THE USE OF MOTOR
DRIVES CONNBCTBD
THROUQH REDUCINQ BOXES, AND THB HIQH MOUNTINQ OF CONVEYORS AND CENTRIFUQALS FOR EASY
HOUSEKEEPING
The fat-free liquor is delivered to Sweetland presses to remove protein and cellulose materials. From the Sweetlands the liquor is delivered to the bone black which has been previously used for the refined sugar channel and the heavy liquor from the converter channel. The light bone liquor is evaporated to approximately 30" BB. and is delivered to the bone black which has been used previously for the white sugar channel. The heavy bone black liquor is delivered to a finishing pan, and then to a cooler and crystallizers. The crystallizers are made of copper-bearing, corrosionresistant, steel plate with the top sheet covering an arc of 5 feet of the circumference and made of Everdur, lined as described for the white crystallizers. This is the portion of the wall of the crystallizer in contact with humid air of liquors a t pH values favorable to rust formation. The crystallizers have previously been partially filled with a mingled magma of second sugar and first liquor. This magma forms the seed foots for the first raw strike. The liquor enters the crystallizer a t about 40" BB. and a temperature of between 120' and 130' F., depending upon the final temperature of the cured mass. The cured sugar is centrifuged in the first raw machines, washed with white greens, if necessary to obtain purities, and delivered to the melt tank. The first raw greens are diluted to 16-18' BB. and given a mild conversion with acid sufficient to hydrolyze the reducing disaccharides with linkages similar to maltose, but not sufficient to break up the polysaccharides with more stable linkages. The conversion is an equilibrium phenomenon;
and more intense hydrolyzing conditions, sufficient to rupture the more stable bonds, would be objectionable. More condensation products would be produced and dry substance would be destroyed and thus form organic acids which are of greater detriment to the second crystallization than the increased yield is worth. The converted first greens are neutralized, atered in Sweetland flters over cloth, and delivered to the bone black which has been used previously for the white and first raws and the heavy second raws. This makes five uses of the bone on liquors of increasingly greater impurity load. The light bone liquor is delivered to evaporators where it is evaporated to about 30" BB. and delivered to the heavy bone which has been used previously on the white and first raws. The bone black liquor is delivered to the finishing pan through the cooler to the crystallizer, where i t is charged on foots from a previously cured batch. The liquor enters at about 41" BB. and 125" F. The final temperature on these crystallizers is as low as possible with the water available. This sugar is centrifuged and delivered to the mingler to be used as seed for the first raw crystallizers. The second raw greens is delivered to the finishing pan, concentrated to 42' BB., and charged into the third raw crystallizers. After being melted, the sugar from these crystallizers is used in liquors of similar purity. RECEIVED Ootober 21, 1938.
Presented before the Division of Sugar Chemistry at the 96th Meeting of the Amerioan Chemioal Soaiety, Milwaukee, Wis., September 6 t o 9, 1938.
