SU1751216A1 - Diffusion juice cleaning method - Google Patents

Abstract

The invention relates to the sugar industry, in particular to the technology of cleaning diffusion juice with lime. The purpose of the invention is to improve the quality of the purified juice. The method of purification of diffusion juice involves its predefinition, defecation, I saturation filtering, defecation before II saturation, II saturation, ripening juice with stirring and filtering. Before the latter, juice II of saturation is divided into clarified juice and thickened suspension, the amount of which is 20-25% by weight of unfiltered juice and a density of 1.15-1.17 g / cm, and then it is subjected to activation with milk of lime in an amount of 0.1-0.15% CaO to the weight of juice for 0.5-1, 5 min. The clarified juice is directed to the filtration. Defecation before and carbonation is carried out by mixing the activated condensed suspension with the filtered carbonation juice I with simultaneous addition of lime in an amount of 0.1-0.15% CaO to the mass of the juice SP

Description

The invention relates to the sugar industry, in particular to the technology of cleaning diffusion juice with lime.

A known method for purifying diffusion juice involves preliming, defecation, first saturation, juice filtration, second saturation with ripening juice, and filtering, while a 1.0–1.1% solution of 1–1 is introduced into the juice of the second saturation before maturing. hydroxyethylenediphosphonic acid in the amount of 1.0-1.5 ob.h. solution of 1000 ob.h. juice.

The disadvantage of this method is the incomplete removal of soluble calcium carbonate from carbonation juice II as a result of incomplete crystallization, as well as the high cost of the reagent used.

The closest to the invention is a method for purifying diffusion juice, which includes preliming, defecation, I saturation, filtration, II saturation, ripening the juice with stirring and filtering it.

The disadvantage of this method is the incomplete removal of calcium carbonate from the juice as a result of a decrease in the rate of its crystallization in the presence of sucrose and a lack of the required crystallization surface area. For these reasons, the calcium carbonate remaining in the solution goes into the purified juice, deteriorating its quality and causing difficulty evaporation and crystallization of sucrose

x |

cl

N5. ™ l

ON

The aim of the invention is to improve the quality of the purified juice.

To achieve this goal, according to the diffusion juice purification kit, which includes preliming, defecation, I-5 uration, filtering, II-saturation, juicing the juice with stirring and sintering, before the last juice II-saturation is divided into clarified juice and the thickened suspension, the amount of which 10 leaves 20-25% by weight of unfiltered juice and a density of 1.15-1.17 g / cm3, then it is subjected to activation with lime milk in an amount of 0.1-0.15% CaO by weight of juice for 0.5- 1.5 min and the clarified juice is directed to the filtering; Before II saturation, is carried out by mixing the activated thickened suspension with the filtered saturation juice I while simultaneously adding 20 lime in an amount of 0.1-0.15% CaO to the juice mass.

The method of cleaning the diffusion juice is as follows.

Diffusion juice is subjected to pre-defecation, defecation, saturation I, filtering, defecation before saturation II, saturation II, ripening for 4-6 minutes and filtering. Before filtering, juice II of carbonation is separated, for example, on hydro-30 cyclones into clarified juice and thickened suspension, the amount of which is 20-25% by weight of unfiltered juice and a density of 1.15-1.17 g / cm. The thickened suspension is subjected to activation with lime milk in the amount of 0.1-0.15% CaO to the mass of juice for 0.5-1.5 minutes. The clarified juice is sent for filtration.

The main cause of incomplete crystallization of calcium carbonate during saturation II 40 and during the maturation of the precipitate is the low mass crystallization rate of the precipitate as a result of the insufficiently developed crystallization surface area. For example, when applying for 45 defecation before lime saturation in the amount of 0.25% CaO by weight of juice, the content of CaCO3 in unfiltered juice does not exceed 0.6% by weight of juice.

An increase in the surface area 50 of the solid phase in the process of saturation and at the stage of ripening of the precipitate makes it possible to significantly increase the mass crystallization rate of CaCO3 and to ensure a sufficiently complete reduction of the calcium carbonate supersaturation 55 in the process of ripening the precipitate. This eliminates the effect of the most harmful part of calcium salts, and significantly reduces the scale deposition rate on the heating surfaces.

evaporating vacuum apparatus and heat exchangers.

Sediment II carbonation has a noticeable residual adsorption capacity with respect to the negatively charged nonsugars left in the juice to be purified. This capacity is enhanced by increasing the positive zeta potential of the sludge when it is activated, achieved by treating with lime in an amount of 0.1-0.15% CaO to the mass of juice for 0.5-1.5 minutes. Preliminary contact of the precipitate with pure lime milk allows to obtain a high charge density on the surface of the sediment and noticeably improve its adsorption characteristics.

Defecation before saturation II is carried out by mixing the activated thickened suspension with the filtered saturation juice I, while adding lime in an amount of 0.1-0.15% CaO to the juice weight. Such a bowel movement can increase the effect of cleaning the diffusion juice and reduce its chromaticity.

Increasing or decreasing the contact time of sludge and milk of lime, as well as a change in the amount of lime consumed to carry out the activation of sludge II saturation compared to the specified optimal values, worsens the conditions of activation and reduces the overall efficiency of juice cleaning.

Return of the thickened suspension of sediment II carbonation in the amount of 20-25% by weight of unfiltered juice with a density of 1.15-1.17 g / cm ensures the solids content in the saturation juice in an amount of 4-5% by weight of juice. When reducing the amount of the condensed suspension returned to less than 20% by weight of the juice and reducing its density to less than 1.15 g / cm3, the solids content in the juice at the outlet of the saturator decreases. In this case, the crystallization surface is insufficient to possibly completely dissolve the dissolved calcium carbonate in crystalline form. At the same time, the adsorption capacity of the saturation precipitate also decreases, which leads to a decrease in purity and an increase in the color of the purified juice,

With an increase in the amount of the returned suspension of more than 25% by weight of the juice and an increase in its density of more than 1.17 g / cm3, an excessive accumulation of the solid phase occurs in the graded juice. In this case, the quality of the purified juice is reduced. This is due to the significant increase in jSM viscosity of system II saturation and the formation of calcium carbonate particles with increased solubility.

Example 1 (known method). Diffusion juice (3 kg), having a CB of 14.3%, DB of 86.2%, pH 6.12, is treated with lime (progressive preliming in the amount of 0.25% CaO at 50 ° C for 15 minutes, subjected to basic defecation 2 , 0% CaO at 50 ° C for 30 minutes and at 85 ° C for 10 minutes, then the defected juice is subjected to the first CO2 saturation to a pH of 11.0 at 85 ° C for 10 minutes and filtered. The filtered juice is the first carbonation heated to 95 ° C, 0.25% CaO is added to it and subjected to a bowel movement for 4 minutes. After this, the second carbonation of CO is carried out for 10 minutes and placed in a container for heating. and equipped with a circulation circuit. After 10 minutes from the start of ripening, the juice is filtered and the following parameters are determined: pH 9.18; DB 89.4%; chromaticity 23 units, calcium salt content 0.07% CaO by weight of juice .

PRI mme R 2. Diffusion juice with a CB of 14.3%, DB 86.2% ipH 6.12 are treated with lime (progressive defecation) in an amount of 0.25% CaO at 50 ° C for 15 minutes, Subject to main defecation 2.0% CaO at 50 ° C for 30 minutes and at 85 ° C for 10 minutes. Then the defecated juice is subjected to the first carbonation of CO2 to a pH of 11.0 at 85 ° C for 10 minutes and filtered. After II saturady, carried out for 10 minutes, the juice is sent to ripen the sediment for 4 minutes. After that, 3 kg of unfiltered juice is subjected to the separation of the suspension using a hydrocyclone. The lower gathering of the hydrocyclone (condensed suspension), the amount of which is 20% by weight of juice with a density of 1.15 g / cm3, is activated by lime milk in an amount of 0.1% CaO by weight of juice for 0.5 min, then mixed with filtered carbonation juice with the simultaneous addition of lime in an amount of 0.1% CaO to the mass of juice, heated to 95 ° C and sent to a bowel movement before II saturation. The upper gathering of the hydrocyclone (clarified suspension) is sent for filtration and the following parameters are determined: pH 9.22; DB 89.7%; chromaticity 20 conventional units; the content of calcium salts is 0.05% CaO by weight of juice.

Thus, compared with the known method, db juice rises by 0.3%; the color is reduced by 13% and the content of calcium salts by 0.02% CaO.

Example 3. A diffusion juice with a CB of 14.3%, D686.2% and a pH of 6.12 is treated to obtain a filtered juice of saturation I in the same way as in Example 2. After II saturation

sediment is directed to ripening for

5 minutes. Then 3 kg of unfiltered juice is subjected to the separation of the suspension using a hydrocyclone. The lower gathering of a hydrocyclone (condensed suspension), the amount of which is 23% by weight of juice with a density of 1.16 g / cm, is subjected to activation with lime milk in an amount of 0.12% CaO by weight of juice for 1 minute. Then mixed with filtered juice I saturation with the simultaneous addition of lime in an amount of 0.12% CaO to the mass of juice, heated to 95 ° C and sent to a bowel movement before II saturation. The upper gathering of the hydrocyclone (clarified suspension) is directed to filtration and the following parameters are determined: pH 9.25; DB 89.9%; chromaticity 18 conventional units; the content of calcium salts is 0.045% CaO by weight of juice.

Compared to the known method, the DB of juice increases by 0.5%, the color decreases by 21%, and the content of calcium salts is reduced by 0.025% CaO.

Example 4. Diffusion juice with a CB of 14.3%, DB of 86.2% and a pH of 6.12 are processed until a filtered juice of saturation I is obtained, similarly to Example 2. After the II saturation, the precipitate is directed to maturation during

6 min. Then 3 kg of unfiltered juice is subjected to the separation of the suspension using a hydrocyclone. The lower gathering of the hydrocyclone (thickened suspension), the amount of which is 25% by weight of juice with a density of 1.17 g / cm3, is subjected to activation with lime milk in an amount of 0.15% CaO for 1.5 minutes, then mixed with filtered juice I saturation with the simultaneous addition of lime in an amount of 0.15% CaO to the mass of juice, heated to 95 ° C and sent for defecation before saturation. The upper gathering of the hydrocyclone (clarified suspension) is directed to filtration and the following parameters are determined: pH 9.23; DB 89.7%. chromaticity 21 conditional unit; the content of calcium salts is 0.055% CaO by weight of juice.

Compared with the known method, the proposed method allows improving the quality of juice by 0.3-0.5%. reduce its chromaticity by 15-20% and the content of calcium salts by 0.02-0.025% CaO.

Claims (1)

DETAILED DESCRIPTION OF THE INVENTION The method of purification of diffusion juice, including predefinition, defecation, first saturation, filtration, defecation before the second saturation, second saturation, ripening of the juice with stirring and filtering, characterized in that ..:. 7 1751216. 8. the quality of the purified juice, before the filter is 1.5 minutes and the filtering is directed; the juice of the second saturation is separated; the juice is wrinkled; clarified juice and thickened suspension, the second saturation is carried out by the amount of which is 20-25% of the mixing of the activated condensed the weight of unfiltered juice and the density of the suspension with filtered juice first 1.15-1.17 g / cm, and then it is subjected to saturation while adding limes in the amount of lime in the amount of 0.1-0.15% CaO by weight 0.1-0.15% CaO to the mass of juice for 0.5-juice.