RU2160315C1 - Method of refining diffusion juice - Google Patents

Abstract

FIELD: sugar industry. SUBSTANCE: diffusion juice, after separation of pulp, is heated and filtered through perlite bed to remove coarse particles. Filtered juice is subjected to membrane filtration in closed flow circuit of membrane installation with no air access on microfiltering membrane to produce filtrate containing low- molecular and colloidal substances and concentrate containing the rest of suspended particles, high-molecular substances, and microorganisms. Concentrate is treated with steam at 100-120 C for 1-2 min and transferred into perlite filtration stage. Invention allows purity of diffusion juice to be increased by 1.6-1.8% and filtration rate to be increased by 15-16%. EFFECT: enhanced refining efficiency. 1 dwg, 1 tbl, 2 ex

Description

 The invention relates to a technology for sugar production, in particular to a technology for purifying diffusion juice with lime, carbon dioxide and membrane filtration.

 A known method of purification of diffusion juice, involving ultrafiltration of the juice, adding water to the concentrate and conducting a second ultrafiltration, mixing the obtained sugar-containing filtrates and further purification of the mixture with lime [1].

 The disadvantages of the method include double ultrafiltration, which complicates the method and at the same time does not provide the required membrane filtration efficiency. In addition, there is a dilution of the juice, which in the future must be thickened.

 A known method of purification of diffusion juice, comprising treating it with calcium hydroxide, carbon dioxide, separating the precipitate and membrane filtration in a closed filtration loop [2].

 The disadvantage of this method is the low efficiency of membrane filtration due to the rapid clogging of pores in the membranes with a gel-like precipitate.

 A known method of purification of diffusion juice without lime-carbon dioxide treatment. The method includes separating the pulp from diffusion juice, heating, filtering with perlite and thickening the juice [3] - prototype.

 The disadvantage of this method is the low degree of purification of the diffusion period before its thickening, which is purified using perlite only from suspended and mucous substances, which leads to the boiling of juice to precipitate primarily high molecular weight substances on the heating surface, reduce its heat transfer coefficient, increase the thickening time , reducing the quality of juice and the operating time of the equipment used.

 The technical result of the invention is to improve the quality of the juice.

To achieve this result, in the proposed method for purifying diffusion juice, which includes separating the pulp from it, heating and filtering it through a perlite layer to separate coarse particles, the filtered juice is subjected to membrane filtration in a closed circulation loop of the membrane unit without air access on microfiltration membranes to obtain a filtrate, containing low molecular weight and colloidal substances, and a concentrate containing residues of suspended particles, high molecular weight substances and m kroorganizmy. In this case, the concentrate is treated with steam at a temperature of 100-120 ^o C for 1 to 2 minutes and sent to filter the juice with perlite.

 The drawing shows a diagram of the implementation of the method.

The method of purification of diffusion juice is as follows. Diffusion juice is passed through a mesohead, then heated to 80 - 85 ^o C and filtered in two stages. At the first stage, the juice is passed through a layer of perlite. The obtained filtrate is sent to the second stage, consisting of membrane filtration in a closed filtration loop to obtain a filtrate containing sucrose and concentrate. The latter after processing it with steam with a temperature of 100 - 120 ^o C is sent to the first stage.

 Membrane filtration is carried out on microfiltration membranes in a closed circulation circuit without air access. When juice moves through the membrane apparatus, the flow is divided into a filtrate containing water, sucrose dissolved in it, low molecular weight and colloidal substances, and a concentrate that contains the remains of suspended particles, high molecular weight substances and microorganisms. The filtrate is served for thickening.

The precipitate of the concentrate has a mucous consistency, which causes difficulty in filtering. The filterability of such a precipitate increases sharply if the concentrate is treated with steam at a temperature of 100 - 120 ^o C for 1 to 2 minutes The concentrate thus prepared is sent to the first filtration stage through a perlite layer.

 Example 1

 Purify the juice according to the prototype.

Diffusion juice with a purity of 86.7% is passed through a pulp separation device. Next, the juice is heated to 80 ^o C and filtered through a layer of perlite. The filtrate is concentrated to the desired concentration, and the precipitate after filtration is removed. The purity of the diffusion period did not change. The filtration rate is 4.7 l / min • m ² .

 Example 2

 Purify the juice according to the proposed method.

Diffusion juice with a purity of 86.7% is passed through a pulp separation device. Next, the juice is heated to 80 ^o C and filtered through a layer of perlite (first stage). The filtrate is passed through a membrane microfilter (second stage). The obtained filtrate is directed to thickening, and steam with a temperature of 110 ^o C is introduced into the concentrate for 1 min, after which the concentrate is returned to the first filtration stage.

 The purity of the juice after the second stage of microfiltration rises to 88.5%.

The filtration rate in the first stage is 6.9 l / min • m ² .

 The test results are shown in the table.

 The proposed method helps to increase the purity of diffusion juice by 1.7%, increase the filtration rate by 1.5 times and the effect of juice purification by 13.6%.

Used sources:
1. Express information. Sugar industry TsNIITEIpishcheprom, M., 1974, issue. 3., p. 24 - 27
2. RU 2081921 C1 06.20.97.

 3. Obtaining sugars from diffusion juice without lime treatment / Stangeev V.O. Belostotsky L.G., Piskovets V.A. et al. // J. Sugar, 1999, N 1, p. 11 is a prototype.

Claims (1)

A method for purifying diffusion juice, comprising separating pulp from it, heating and filtering it through a perlite layer to separate coarse particles, characterized in that the filtered juice is subjected to membrane filtration in a closed circulation loop of the membrane unit without air access on microfiltration membranes to obtain a filtrate containing low molecular weight and colloidal substances, and a concentrate containing residues of suspended particles, high molecular weight substances and microorganisms, while entrat treated with steam with a temperature of 100 - 120 ^o C for 1 - 2 minutes, and fed to a filtration juice with perlite.

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