US 1850036 A
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March 15, 1932. c, STEFFEN, JR 1,850,036
PROCESS FOR OBTAINING TRICALCIUM SACCHARATE RICH IN SUGAR AND POOR IN LIME AND OF A VERY HIGH DEGREE OF PURITY Filed April 27, 1926 Patented Mar. 15, 1932 PATENT OFFICE CARL STEFIB'EN, 33., OF VIENNA, AUSTRIA PROCESS FOR OBTAINING TBICALCIUM SACCHABATE RICH IN SUGAR AND POOR IN LIME AND 01 A VERY HIGH DEGREE OF PUBI'IY Application filed April 27, 1928, Serial No. 105,011, and in Austria May 18, 1825.
This invention relates to a process for obtaining tricalcium saccharate rich in sugar and poor in lime and of a very high degree of purity.
"5 It is known that molasses sugar is obtained by various extraction processes wherein the sugar is precipitated with calcium made as an insoluble tricalcium saccharate. The tr1- calcium saccharate suspended in the liquid is brought to a higher concentration by filtration through filter presses, so that the saccharate filtered ofl' still has a water content of about 70%, and in this water is still to be found the same percenta e of non-sugar elements as was present in t e precipitatlon liquid. The process therefore does not succeed in completely separating the sugar from the non-sugar elements, but there always remains a part of the non-sugar elements in the water content of the saccharate. In order now partly to remove from the saccharate the quantities of remaining non-sugar elements, or in order to obtain from the outset as low a content as possible of non-sugar products in the water remaining in the saccharate cake, various methods have been proposed, of which however none has led to practical success.
It has been found thatlif. from 1 to 3 times the quantity of the sugar content of a cold low-percentage (0.8-2%) sugar solution (dilute juices, sweet washings, waste liquids or molasses), is introduced in the form of separated tricalcium saccharate and mashed into said solution, said tricalcium saccharate decomposes only in part and the lime liberated by the decomposition combines immediately with the sugar of said sugar solution to form a soluble sugar lime compound, Whilst the remainder of the tricalcium saccharate remains completely undecomposed. If finely powdered lime is now added to this mixture, the soluble sugar lime compound present in the mixture is precipitated by the lime as an insoluble sugar lime compound. 4 The saccharate thus obtained is separated by pressing in filter presses for the purpose of increasing the concentration. This saccharate has the same composition as regards the relative proportions of sugar and lime, as that obtained by treating an ordinary sugar solution with lime and is found to be a tricalcium saccharate rich in sugar and poor in lime and of very high purity, the coeificient of purity being 97 to 98.
A second way of carrying out the invention 55 consists herein, that a tricalcium saccharate, which is obtained from molasses, is mashed with lime water and the masked saccharate is added to a low percentage cold su r solution. The lime set free by the partia decom- 50 position of the tricalcium saccharate, which has resulted from the mashing with lime water, combines with the sugar of the low percentage sugar solution to form a soluble sugar lime compound. Fresh quantities of powo dered lime are added to this saccharate mashed in the sugar solution for further precipitation. The result is identical with that o the first method.
A further method of carrying out the roc- 7o ess consists in a combinat1on of one o the processes hereinbefore described with a known combined precipitation and urifying process for the treatment of sugar fime.
According to the said known process an impure sugar solution of a high concentration (from 5 to 7% sugar) is precipitated to form tricalcium saccharate and the liquid containing the latter is passed into a filter press until the pressure rises from 1 to 2 atmospheres, 30 whereupon the cake obtained is washed with a liquid containing tricalcium saccharate which liquid is produced by precipitating with lime a low percentage sugar solution (2%) from molasses, or a low grade syrup, which conse- 5 quently has a much lower non-sugar content.
By this means the high non-sugar content of the tricalcium saccharate cake, first obtained, is displaced and a tricalcium saccharate of a higher degree of purity is obtained. 00
In both of the above described methods according to the present invention, there is addedto an approximately 0.8 per cent sugar solution (preferably dilute juices), about sugar, and mashed in the form of tricalcium sacchara-te such as mashed sugar lime, and subsequently fresh quantities of powdered lime are added for precipitating the sugar still present. This precipitation li uid so formed has a non-sugar content 0 about 100 0.31% and, in accordance with the present invention, is used as the washing liquid in the filter press in carrying out the said known combined precipitation and purifying process. The quantity of the said washing liquid of high purity is three to three and a halt times the quantity of the contents of the press and is pressed in the filter press till apressure of 4-5 atm. is reached. Then the liquid from the first precipitation, which is of high nonsugar content is substituted by the liquid of the second precipitation which is poor in nonsugar content. In this manner saccharates of purity co-efficients 97 to 98 are obtained. In this operation an amount of about 25% of the washed saccharates obtainedis returned into the precipitation operation, for washing purposes, whilst the other 75% are led away into the separating station of the factory.
The economic result of the invention lies in the production of saccharate of very high degree of purity, and in which the consumption of lime is the same as with the normal precipitation. The achievement of high purities is of great importance for the factory operation, since the purity is not impaired, but is increased, by the introduction of the saccharate into the dilute juice. Particularly in the manufacture of white sugar is it of great importance to manufacture saccharates of high purity, because, in order to produce sugar of quality, juices of light colour are necessary. The saccharate of low purity contains however large quantities of colouring matter, whereby the juices in the factory become. very dark, from which products of good quality can be repared only with difliculty. A further a vantage consists herein, that this process permits a higher concentration of the added liquid of the first precipitation, whereby firstly the sugar losses are decreased in consequence of the quantities of waste lye being diminished and secondly waste lyes of higher concentration are obtained, which makes a lye evaporation more profitable.
The drawing shows diagrammatically by way of example one form of construction of an apparatus for carrying out the process.
From the container L solution flows through the pipe a, and from the molasses container W molasses pass through the pipe 6, into the precipitating apparatus F so that the added liquid has a sugar content of about 6 to 6.5%. This added liquid is subjected to a normal precipitation process, for which purpose the pump T sucks the liquid to be precipitated through the pipe 0 and forces it through the cooler K into the container S in which finely divided powdered lime is continuously strewn through the lime supplying apparatus M on the flowing precipitation liquid. The liquid supplied flows from the container S into the precipitating apparatus F from which the preci itation liquid again flows through the pump through the cooler K into the container S into which powdered lime is again fed. This cycle is repeated until the necessary tricalcium saccharate is formed, whereupon the precipitation operation is terminated. This is the formerly known precipitation operation.
The liquid containing the tricalcium saccharate is then sucked away by the pum P through the pipe 0 and is forced throug the pipe 0 into the filter press A The solution flowing away from the filter press is led away through the pipe (1 into the sewer, or into a solution vaporizer if used. The tricalcium saccharate separated in the press A is discharged into the masher B into which, in addition, through the pipe f diluted cold juice (syrup or molasses) of 1 to 2% sugar content from the collecting container D is added for mashing. The mashed saccharate is forced by the pump P from the masher B and the pipe e through the pipe e into the container R provided with a stirring apparatus. In the second precipitation apparatus water and dilute juice (syrup or molasses) are deposited to form a 1 to 2% sugar solution in the collecting vessel F Hereupon the pump T is putin operation to suck the initial liquid from the collecting vessel F 2 and the pipe 72. and to force'it through the cooler K into the container S In addition, the mashed saccharate obtained in the first process is allowed to fiow from the container B through the pipe 9 into the container S The mixture flows ofi from the container S into the collecting vessel F from which the pump T forces this liquid again into the container S This cycle is repeated until the'mashed saccharate in the mash is fed to the precipitation apparatus. So much saccharate is aded to the starting liquid that the quantity of sugar in the saccharate corresponds to from one and a half to three times the quantity of sugar of the starting liquid. When the introduction of this mashed saccharate is completed fresh quantities of finely powdered lime are supplied through the lime delivery apparatus M to the circulating precipitation liquid, and this is continued until the precipitation liquid becomes precipitated so that it contains only approximately 0.5% sugar in dissolved state. Herewith the second precipitation operation is completed. After completion of the operation the liquid containing the tricalcium saccharate is sucked away by the pump P through the pipe h, and is forced through the pipe k into the press A The solution running off from this press is led away through the pipe m into the container L and is forced by thepump P through the pipe n into the container L This solution serves again as a starting liquid for a first precipitation process. The saccharate filtered ofi in the filter press A, ar-
rives in the masher B from which the saccharate is led away through the pipe 8 into the separating station of the factory. The saccharate thus obtained has a purity efiicient of from 97 to 98. The pipe f, serves for conveying lime water to the dilute in the elements F K and S in order to further dilute the juice and to render it slightly alkaline.
' A second form of execution of the process I consists herein, that instead of a dilute su r solution lime water is used in the masher 1 for the mashing operation. The operation. is otherwise identical with thatof the first method.
What I claim is:
1. Process for obtaining tricalcium saccharate rich in sugar and poor in lime and of a very high co-efiicient of purit comprisin mashing saccharate with a co dsolution 0 low sugar content in such a manner that from one and a half times to three times the amount of sugar is supplied in the formof separated tricalciumsaccharate to the su r contained in said sugar solution, said sacc arate having been separated from a molasses solution in a Erecedm normal precipitating process, and nally a ding lime to t e mixture in order to precipitate the calcium saccharate dissolved in the mixture.
2. The process according to claim 1 in i which the tricalcium saccharate is mashed with lime water and the mixture obtained is aded to said low percentage cold sugarsolution.
In testimony whereof I aflix m signatura CARL STEFFE Jtm'ron.