RU2343198C1 - Method of purification of sugar-containing solutions - Google Patents

Abstract

FIELD: chemistry, food products.

SUBSTANCE: method includes heating of sugar-containing solution, in particular, diffusion juice or refining of raw sugar, introducing into it flocculant - water-soluble polymer and separation of formed non-sugar sediment. From water-soluble polymers, super-high molecular element-organic compound with active functional and complex-forming groups is used. Purification is carried out by alkaline agents: sodium and calcium hydroxides. In purified solution it is reasonable to introduce bleaching substance, for example, sulfuric acid, phosphoric acid and other.

EFFECT: high effect of purification, with change of qualitative indices of initial sugar-containing solution and reduction of flocculant consumption.

3 cl, 2 ex

Description

The invention relates to the sugar industry.

There is a method of purification of a sugar-containing solution, namely, raw sugar curing, which involves preparing the latter, heating it, introducing phosphoric acid, milk of lime, flocculant to aggregate the precipitate and separating it from the curing, while phosphoric acid is introduced in an amount of 0.01-0 , 06% P ₂ O ₅ , lime milk 0.01-0.1% CaO to the weight of raw sugar, and a heterocyclic cationic polymer in an amount of 0.01-0.07% to the weight of raw sugar, is used as a flocculant particular water soluble polyelectrolyte cation th type MIC-402, which is a high-molecular compound obtained by polymerizing a monomer dimethyldiallylammonium chloride (RU 2061047 C1, 27.05.1996).

The disadvantage of this method is its limited applicability only for sugar-containing solutions with a high dry matter content and a purity of not less than 98%, the need to use CaO for the formation of colloidal particles as a result of its chemical neutralization reaction with phosphoric acid, which, in turn, is an acid of medium strength and requires the use of special hardware.

The closest analogue of the proposed method is a method for purifying sugar-containing solutions, which involves heating the latter, introducing a flocculant - a water-soluble polymer and separating the precipitate of non-sugars. Of water-soluble polymers, an organosilicon polymer compound with active functional and complexing groups is used (RU 2249048 C1, 03/27/2005).

The disadvantage of this method is that the organosilicon polymer compound with active functional and complexing groups has low hydrolytic stability in an alkaline environment, as well as in the presence of metal salts, which leads to a decrease in the molecular weight of this flocculant. This, in turn, reduces the flocculating ability and does not provide a consistently high cleaning effect.

The technical result of the invention is to achieve a consistently high cleaning effect when changing the quality indicators of the initial sugar-containing solution and reducing the consumption of flocculant.

This technical result is achieved by the fact that in the proposed method for the purification of sugar-containing solutions, which involves heating the latter, introducing a flocculant — a water-soluble polymer and separating the precipitate of non-sugars from water-soluble polymers — an ultra-high molecular weight organo-organic substance with active functional and complexing groups of the general formula

where m = 1-9;

Radicals: R ₁ = (CH ₂ ) _n Pol, where n = 2-4;

R ₂ = R ₃ = H; CH ₃ ; C ₂ H ₅ ; C ₃ H ₅ ; C ₃ H ₇ ; C ₄ H ₉ ;

R ₄ = R ₅ = CH ₃ ; C ₂ H ₅ ; C ₃ H ₅ ; C ₃ H ₇ ; C ₄ H ₉ ; C ₆ H ₅ ; OH; OM;

M = Na; K; Cs;

R ₆ = (CH ₂ ) _k , O; where k = 1-4;

R ₇ = R ₁ ; [NR1R2R ₃ ] O;

Pol = Organic polymer from a number of polyvinylamines, polyallylamines, poly-N-vinylamides, polydimethyl diallylammonium halides, polyacrylates, polymethyl acrylates, as well as copolymers and block copolymers from monomers corresponding to the above polymers.

An ultra-high molecular weight element-organic flocculant (SVEF), containing a quaternary ammonium salt of complex nature as one of the radicals, provides synergies between the intermolecular interactions of dispersed and colloidal particles, reduces the gradient of the potential of electric charges, ensures the destruction of structural-mechanical barriers and cohesion with the particle surface, while maintaining bonding with other high molecular weight molecules. Functional groups contained in the frame of the polymer chain provide the solubility of SVEF in various media, the formation of strong bonds not only with the surface of the dispersed phase, but also with other macromolecules.

SVEF with active functional and complexing groups is introduced into the solution in one or several stages with the mixture kept between them and, if necessary, removing the precipitate of non-sugars by centrifugation, filtration or settling.

Sugar-containing solutions can be purified by this method in one or several stages, including processing them with stirring SVEF and then separating the precipitate formed in the presence of alkaline agents, such as: sodium or calcium hydroxides, or without them, with the following values: R ₄ = R ₅ = CH ₃ ; C ₂ H ₅ ; C ₃ H ₅ ; C ₃ H ₇ ; C ₄ H ₉ ; C ₆ H ₅ ; IT; OM, m = 1-9. The value of R ₆ depends on the pH of the medium. For pH <7R ₆ = O, for other values of the hydrogen exponent R ₆ = (СН ₂ ) _k . The proposed method allows the purification of sugar-containing solutions with a purity of less than 76%, and in the case of purification of diffusion juice in the technological process of sugar beet processing, most non-sugars are removed with chips already in the process of extraction of sucrose in a diffusion apparatus. In addition, the proposed technology allows to stabilize the process and make it less sensitive to changes in the quality of raw materials and other technological parameters. Due to the high cleaning effect (45-60%), there is no need for such stages of the technological process as sulfitation, second defecation and saturation, etc. When the color of the solutions being cleaned is high, at the first and subsequent stages of purification, if necessary, a bleaching agent, for example phosphoric acid, sulfuric acid, hydrogen peroxide, etc. is introduced.

The proposed method provides a simplification of the process by eliminating process steps such as sulfitation, defecation, second saturation, reducing costs by reducing the expense or even completely eliminating a number of consumables, such as antiseptics, antifoam agents, anti-scale agents and CaO, and also increases the cleaning effect of sugar-containing solutions, which significantly reduces energy consumption and harmful emissions into the environment.

Example 1. To 1 kg of curing of raw sugar, SV = 57%, CX = 54%, C = 94.7%, heated to 40-55 ° C, with stirring, 0.0001 kg of a 10% SVEF solution is stirred for 10 minutes 0.0002 kg of CaO are added and the mixture is heated to 75-80 ° C with stirring, after which 0.00005 kg of SVEF is added at the following indices in the general formula: R ₁ = (CH ₂ ) ₂ Pol, R ₂ = CH ₃ , R ₃ = C ₃ H ₅ , R ₄ = CH ₃ , R ₅ = C ₂ H ₅ , R ₆ = O, R ₇ = [NR ₁ R ₂ R ₃ ] O; m = 9, Pol = poly-N-vinylamide. The mixture is stirred for 10 minutes, the precipitate formed is removed by filtration or centrifugation, after which the mixture is directed to evaporation and crystallization to obtain sugar. The filtrate of the sugar-containing solution has SV = 54.5%, CX = 54%, H = 99.1%, and the purification effect EF = 83.8%.

Example 2. To 1 kg of diffusion juice, SV = 18.0%, CX = 14.6%, H = 81.1%, heated to 45-55 ° C, add 0.00005 kg of 10% SVEF solution, mix for 5 minutes after which 0.001 kg of CaO are added in three equal portions with stirring and with an interval of 5 minutes, the mixture is heated to 75-80 ° C, after which 0.00005 kg of SVEF is added at the following indices in the general formula: (CH ₂ ) ₃ Pol, R ₂ = C ₂ H ₅ , R ₃ = C ₃ H ₇ , R ₄ = CH ₃ , R ₅ = C ₆ H ₅ , R ₆ = O, R ₇ = [NR ₁ R ₂ R ₃ ] O; m = 3, Pol = polydimethyldiallylammonium chloride. The mixture is stirred for 10 minutes, the precipitate formed is removed by filtration or centrifugation, after which the mixture is directed to evaporation and crystallization to obtain sugar. The filtrate of the sugar-containing solution has SV = 15.8%, CX = 14.6%, 4 = 92.4%, EF cleaning effect = 64.7%.

Claims (3)

1. The method of purification of sugar-containing solutions, providing for the heating of the latter, the introduction of a flocculant - a water-soluble polymer and the separation of the precipitate of non-sugars, characterized in that the water-soluble polymers use an ultra-high molecular weight organo-organic compound with active functional and complexing groups, the general formula of which

where m = 1-9;
radicals: R ₁ = (CH ₂ ) _n Pol, where n = 2-4;
R ₂ = R ₃ = H; CH ₃ ; C ₂ H ₅ ; C ₃ H ₅ ; C ₃ H ₇ ; C ₄ H ₉ ;
R ₄ = R ₅ = CH ₃ ; C ₂ H ₅ ; C ₃ H ₅ ; C ₃ H ₇ ; C ₄ H ₉ ; C ₆ H ₅ ; IT; OM
M = Na; TO; Cs;
R ₆ = (CH ₂ ) _k , O; where k = 1-4;
R ₇ = R ₄ ; [NR ₁ R ₂ R ₃ ] O;
Pol = an organic polymer from a series of polyvinylamines, polyallylamines, poly-N-vinylamides, polydimethyl diallylammonium halides, polyacrylates, polymethyl acrylates, as well as copolymers and block copolymers from monomers corresponding to the above polymers. 2. The method according to claim 1, characterized in that the purification is carried out in the presence of alkaline agents, such as sodium and calcium hydroxides. 3. The method according to claim 2, characterized in that a bleaching substance, for example sulfuric acid, phosphoric acid, polyphosphoric acid, hydrogen peroxide, sodium or calcium hypochloride is introduced into the medium to be cleaned.