US 4,795,494 AGranted

Beet juice purification system

AssigneeThe Western Sugar Company

InventorsLaszlo Toth, Michael R. Conway

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Abstract

A process for the removal of non-sugar impurities from beet diffusion juice having essentially no beet tissue particles therein and comprising water, sugar, and dissolved and colloidal non-sugar impurities. The diffusion juice is subjected to a progressive preliming procedure to thereby produce a limed first juice fraction containing non-sugar flocs and a limed, floc-free second juice fraction. The fractions are separated and the floc-free fraction is subjected to cold and hot main liming. Subsequently, and without substantial mechanical or chemical degradation, at least a portion of the first juice fraction containing at least a portion of the non-sugar flocs is united with the main-limed second juice fraction in a first carbonation procedure wherein carbon dioxide reacts with the lime present to produce calcium carbonate precipitate which, in addition to being an adsorption filter aid, forms protective scales around the floc particles. The resulting single juice fraction is separated, further treated in a second carbonation procedure, and filtered for subsequent sugar crystallization.

Claims10

Dependent claims

(a) subjecting the diffusion juice to a progressive preliming procedure wherein lime and carbonation sludge are added to gradually increase the pH of the juice to about 11.6 to thereby produce a limed first juice fraction containing non-sugar flocs produced from non-sugar impurities which so flocculate and a limed second juice fraction which is floc-free;
(b) separating the first juice fraction containing the non-sugar flocs from the second juice fraction;
(c) subjecting the second juice fraction to a main liming procedure wherein lime is added to the second juice fraction and continuously intimately mixed therewith at ambient temperature to increase the pH thereof to above about 12.6 and wherein the resultant mixture is maintained for a period of time sufficient to degrade non-sugar impurities which are degradable at said temperature;
(d) heating with continuous intimate mixing thereof the mixture of (c) to about 80.degree.-90.degree. C. and maintaining said mixture for a period time sufficient to degrade non-sugar impurities which are degradable at said temperature;
(e) uniting without substantial mechanical or chemical degradation at least a portion of the first juice fraction containing at least a portion of the non-sugar flocs with the resulting second juice fraction of (d) in a first carbonation procedure wherein carbon dioxide gas is introduced in a quantity sufficient to react with at least about 95% of lime present in the first and second juice fractions to thereby produce a single juice fraction and calcium carbonate precipitate which adsorbs certain remaining disolved non-sugar impurities which are so adsorbable and which insulates the non-sugar flocs by creating permanent calcium carbonate scales around each floc particle;
(f) separating the single juice fraction of (e) and further treating said juice fraction in a second carbonation procedure wherein the juice is heated to a temperature immediately below the boiling point of the juice and carbon dioxide gas is introduced in a quantity sufficient to react with substantially all lime there present to thereby produce calcium carbonate precipitate and a final juice fraction;
and
(g) separating the final juice fraction of (f) from the calcium carbonate precipitate.

5 more elements

(a) subjecting the diffusion juice to a progressive preliming procedure wherein lime and carbonation sludge are added to gradually increase the pH of the juice to about 11.6 to thereby produce a limed first juice fraction containing non-sugar flocs produced from non-sugar impurities which so flocculate and a limed second juice fraction which is floc-free;
(b) separating the first juice fraction containing the non-sugar flocs from the second juice fraction;
(c) subjecting the second juice fraction to a main liming procedure wherein lime is added to the second juice fraction and continuously intimately mixed therewith at ambient temperature to increase the pH thereof to above about 12.6 and wherein the resultant mixture is maintained for a period of time sufficient to degrade non-sugar impurities which are degradable at said temperature;
(d) heating with continuous intimate mixing thereof the mixture of (c) to about 80.degree.-90.degree. C. and maintaining said mixture for a period time sufficient to degrade non-sugar impurities which are degradable at said temperature;
(e) subjecting the resulting second juice fraction of (d) to a first carbonation procedure wherein carbon dioxide gas is introduced in a quantity sufficient to react with at least about 95% of lime present in the second juice fraction to thereby produce a second juice fraction and calcium carbonate precipitate which adsorbs certain remaining dissolved non-sugar impurities which are so adsorbable;
(f) subjecting at least a portion of the first juice fraction containing at least a portion of the non-sugar flocs to a separate carbonation procedure wherein carbon dioxide gas is introduced in a quantity sufficient to react with at least about 95% of lime present in the first juice fraction to thereby produce a first juice fraction and calcium carbonate precipitate which adsorbs certain remaining dissolved non-sugar impurities which are so adsorbable and which insulates the non-sugar flocs by creating permanent calcium carbonate scales around each floc particle;
(g) separating out the juice fraction of (e) and the juice fraction of (f) and uniting the resulting juice fractions of (e) and (f) to form a single juice fraction and further treating said single juice fraction in a second carbonation procedure wherein the juice is heated to a temperature immediately below the boiling point of the juice and carbon dioxide gas is introduced in a quantity sufficient to react with substantially all lime there present to thereby produce calcium carbonate precipitate and a final juice fraction;
and
(h) separating the final juice fraction of (g) from the calcium carbonate precipitate.

6 more elements

Dependencies are inferred from the claim text.