US2214281A - Process for manufacturing sugar - Google Patents

Description

Sept. l0, 1940. R, L LAY PROCESS FOR MANUFACTURING SUGAR Filed June 27, 1938 INVENTOR. @0V L. LAY.

TTORNEY.

Patented Sept. 10, 1940 UNITED STATES PROCESS FOR MANUFACTURING SUGAR Roy L. Lay, Rocky Ford, Colof, assignor of onethird to Walter J. Kellogg and one-third to I. W. Reed, both of Rocky Ford, Colo.

Application June 27, 1938, Serial No. 216,076

2 Claims.

This invention relates to an improvement in processes for the manufacture of sugar, more particularly beet sugar.

The principal object of the invention is to pro- 5 vide a process step which will reduce the lime content of the juices before evaporation so as to reduce the formation of scale deposits on the heating surfaces of the factory evaporators and vacuum pans.

Another object of the invention is to provide rf-a simple process step which can be easily accomplished in the standard beet sugar .factory without changes or additions to the equipment thereof, and Without requiring additional reagents or treatments, which will substantially eliminate lime salts and other soluble impurities from the thin juice to produce a higher purity of juice and a higher sugar yield therefrom.

Other advantages will become apparent from the following description of the process and from its use.

In the following description of the process, reference is had to the accompanying drawing which illustrates a typical iiow diagram of the rst carbonation step in the usual sugar manufacturing process with this invention incorporated therein.

Usual process Water or hot juices therethrough in the cells of a diffusion battery. The raw juice from the dif- 35 fusion battery, indicated by the flow line I0 on the diagram, is stored in a raw juice tank II. The juice is drawn from the storage tank II, heated in raw juice heaters, indicated at I3, and passed to first carbonation tanks, I4, where o it is treated with CO2 gas to precipitate the lime and suspended solid matter therefrom. It is then reheated if necessary in a irst carbonation heater, I5, and passed to thickeners or settling tanks I6 to settle out the solid suspensions. 45 The partially clarified juice from the thickeners I6 is passed to a suitable receiving tank I'I and, from thence, to second carbonation heaters I8. The latter raise the temperature of the juice to the proper point for a second carbona- 50 tion which is carried out in second carbonation tanks I9 to precipitate the remaining lime. From the second carbonation tanks, the carbonated juice is passed as indicated by the flow line passed to filter presses designated second car- 55 bonation presses to filter out of the nal solids thrown down in the second carbonation. From thence the clarified juice passes to the evaporators and pans for crystallizing out the sugar.

The sludge and thickened juice from the thickeners I6 passes to a sludge mixing tank 2 I, thence -5 torst carbonation lter presses 20 usually of the Oliver vacuum type. The presses filter the sludge o-r mud from the thickened juice, producing a pick-up in receiver` 25. The pickup juice is substantially clear but carries a high 10 percentage of excess lime from the first carbonation. The mud or sludge cake from the presses is washed before being discarded to Waste, as indicated at 28. The Wash waters, carrying the remaining sugar and more or less solid matl5 ter, are passed to a Wash receiver 26.

In the usual factory, the approximately onethird of the pick-up juice is passed by means of a pump 34 from the receiver 25 to a low melter, 2'I, where the temperature is raised to 20 lessen the viscosity of the juice and it is then pumped back by means of a pump 35 to the raw juice line as indicated by the flow line 24. The remaining two-thirds was formerly pumped back to the now line su, as indicated by the broken 25 flow line 33-32, and is then passed directly to the 2nd carbonation presses without additional carbonation.

In the present factories one-half of the sweet Wash Waters are diverted from a sweet Water 30 pump 36 and used for thinning saccharate cake, in a saccharate mixing and heating tank 29, and are then passed, with the dissolved saccharate cake by means of a saccharate pump 31 to the raw juice line, as indicated by the line 38. 'Ihe 35 remaining half of the sweetwaters are at present passed directly Afrom the pump 36, back to the second carbonation line 30, as indicated at 33, without further carbonation.

Both the returned pick-up juices and the re- 40 turned wash waters carry lime and other soluble and insoluble impurities, a large percentage of which could be eliminated by an additional carbonation. Yet these sweetwaters and juices are passed directly to the second carbonation presses without carbonation and thence to the evaporators and pans where the impurities are eliminated in the formation of heavy scale deposits upon the heating surfaces.

Improved process In this improved process the old ow lines 32 and 33 are eliminated and the excess pickup juice from the pick-up receiver 25, and the excess Sweetwater from the wash receiver 26 is 55 passed back to the raw juice iioW line ahead of the first carbonation tanks i4, as indicated by the flow line 3|. From thence it flows With the incoming raw juice to the rst carbonation tanks Where it is retreated With the caustic lime and CO2 and passed to the thickeners IB, and from thence to the second carbonation and filter phases.

By this method all the sweetvvaters and all pick-up juices are subjected to repeated carbonation until they reach a stage of purity equal to that of the juice entering the second carbonation. Thus, the second carbonation, not only eliminates the lime and other soluble impurities from the raw juice but also, at the same time, eliminates them from the intermixed sweet- Waters and pick-up juices Without additional equipment. No additional pumps are required since the present pumps 34 and 36 are employed in the return of the juice to the rst carbonation.

The elimination of the lime and other soluble impurities from the evaporators and pans results in a great saving in fuel and equipment due to the elimination of objectionable scale as Well as the saving of time and materials ordinarily required for the periodical removal of the scale deposits.

The process is not necessarily limited to the exact procedure and process as shown on the diagram and as described herein. It is only to be considered as limited by the terms of the accompanying claims in which it is intended to claim all novelty inherent in the invention as broadly as permissible in View of the prior art.

Having thus described the invention, What is claimed and desired secured by Letters Patent i. In a process for the manufacture of sugar of the type having the following steps, carbonation cf the juice, filtration of the juice from the sludge, pressing of the sludge to extract the juice remaining therein, washing of the pressed sludge cake, a second carbonation of the juice from the filtration step, a pressing of the juice from the second carbonation step; the intermediate step o returning all of the Waters from the Washing step and all of the juice from the first pressing step to the rst carbonation; thence passing them through the second carbonation to further purify them before passing them to the second pressing step along With juices from thc second carbonation.

2. Theherein described method of reducing the lime content of the juices before evaporation in a sugar manufacturing process in Which the incoming crude juice is successively subjected to a first and a second carbonation step before evaporation, comprising: introducing into the incoming crude juice before carbonation the Wash Waters and pick up juices from thefirst carbonationstep.

ROY L. LAY.

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