CN101810262B - Xylitol mother liquor crystallization method - Google Patents

Abstract

The invention discloses a xylitol mother liquor crystallization method, belonging to the technical field of functional sugar production. The crystallization method adds three steps of dehydration promotion, room-temperature placement and freezing crystallization on the basis of the traditional crystallization method, adopts a dehydrating agent and a accelerator, and comprises the following specific technical steps: (1) prethickening; (2) dehydration promotion; (3) cooling crystallization; (4) displacing at room temperature; (5) freezing crystallization; (6) decentralizing; and (7) drying, packaging and the like. The crystallization method of the invention solves the problem of difficult crystallization of xylitol mother liquor, improves yield, fully utilizes raw materials, improves purity and quality of xylitol crystals, and improves the additional value of the xylitol mother liquor. The invention is also suitable for xylitol crystallization.

Description

Xylitol mother liquor crystallization method

technical field

The invention belongs to the technical field of functional sugar production and relates to a crystallization method of xylitol mother liquor.

Background technique

Xylitol is obtained by hydrogenating xylose, and the xylitol solution is purified, evaporated, vacuum crystallized, and centrifuged to obtain xylitol crystals. The traditional vacuum crystallization method in xylitol production is to pre-concentrate massecuite to a supersaturated state, add seed crystals, cool down in vacuum to crystallize, and centrifuge to obtain crystals. In the production of crystal xylitol, a large amount of xylitol mother liquor will be produced. Due to the many impurities and low purity of xylitol mother liquor, crystals cannot be obtained by traditional vacuum crystallization methods. Xylitol mother liquor can only be used as liquid xylitol. . Liquid xylitol brings great inconvenience to storage and transportation. Due to its low purity, its application range is also limited and its added value is low.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a method for crystallization of xylitol mother liquor to solve the problem that the prior art cannot obtain crystals and can only be used as liquid xylitol. Due to the low purity, the scope of application is also limited, and the added value is relatively high. Inferior question.

The technical scheme adopted by the present invention to solve its technical problems is to provide a new crystallization method of xylitol mother liquor, which adds three steps of dehydration promotion, room temperature placement, and freezing crystallization on the basis of the traditional crystallization method, and adds dehydration agent and accelerator, the crystallization method consists of the following process steps:

1. Pre-concentration: vacuum concentrate the xylitol mother liquor to a concentration of 75-95%.

2. Dehydration promotion: when the pre-concentrated massecuite in step 1 is cooled to a temperature of 44-52°C, one or both of glycerin and absolute ethanol are added according to 0.1-5% of the massecuite’s bulk density. One or both of sodium gluconate and potassium sorbate are added to 0.01-0.10% of the dry weight of the paste.

3. Cooling and crystallization: Put the mother liquor treated in step 2 into a super constant temperature water bath, add xylitol micropowder according to 0.2-0.8% of the dry weight of the massecuite at a temperature of about 45°C, cool down and crystallize for 10-36 hours, appropriate Extend cooling time.

4. Place at room temperature: Take the massecuite crystallized in step 3 out of the water bath, and place it at room temperature for 16-32 hours. The massecuite turns white and the crystal grains increase.

5. Freezing and crystallization: Put the massecuite after standing at room temperature in step 4 into a refrigerator at 4°C, and freeze and crystallize for 8-72 hours.

6. Centrifugation: Centrifuge the frozen crystal massecuite to obtain crystals.

7. Dry the package.

By adopting the method, the problem of difficult crystallization of the xylitol mother liquor is solved, the yield is increased, the raw materials are fully utilized, the purity and quality of the xylitol crystals are improved, and the added value of the xylitol mother liquor is increased. The present invention is equally applicable to xylitol crystallization.

specific embodiment

Get xylitol mother liquor 1000g, refer to several different ways of adding dehydrating agent and accelerator, provide the following specific implementation examples.

Example 1

1. Pre-concentration: Take 1000 g of the xylitol mother liquor and concentrate it in vacuum to a concentration of 75%.

2. Acceleration of dehydration: When the pre-concentrated massecuite in step 1 is cooled down to 50°C, add 0.58ml of absolute ethanol and 0.14g of sodium gluconate.

3. Cooling and crystallization: put the mother liquor treated in step 2 into a super constant temperature water bath, add 3.9g of xylitol micropowder at a temperature of 44°C, and cool and crystallize for 10 hours.

4. Place at room temperature: Take the massecuite crystallized in step 3 out of the water bath, and place it at room temperature for 24 hours. The massecuite turns white and the crystal grains increase.

5. Freezing and crystallization: Put the massecuite after crystallization at room temperature in step 4 into a refrigerator at 4°C, and freeze and crystallize for 39 hours.

6. Centrifugation: Centrifuge the frozen crystal massecuite to obtain crystals.

7. Dry the package.

Example 2

1. Pre-concentration: Take 1000 g of the xylitol mother liquor and concentrate it in vacuum to a concentration of 78%.

2. Acceleration of dehydration: When the pre-concentrated massecuite in step 1 is cooled to 50°C, add 0.4 ml of absolute ethanol, 0.2 ml of glycerin, and 0.24 g of sodium gluconate.

3. Cooling and crystallization: Put the mother liquor treated in step 2 into a super constant temperature water bath, add 3g of xylitol micropowder at a temperature of about 45°C, and cool down and crystallize for 11 hours.

4. Place at room temperature: Take the massecuite crystallized in step 3 out of the water bath, and place it at room temperature for 15.5 hours. The massecuite turns white and the crystal grains increase.

5. Freezing and crystallization: Put the massecuite after standing at room temperature in step 4 into a refrigerator at 4°C, and freeze and crystallize for 16 hours.

6. Centrifugation: Centrifuge the frozen crystal massecuite to obtain crystals.

7. Dry the package.

Example 3

1. Pre-concentration: Take 1000 g of the xylitol mother liquor and concentrate it in vacuum to a concentration of 78%.

2. Acceleration of dehydration: When the pre-concentrated massecuite in step 1 is cooled to a temperature of 45°C, add 44ml of absolute ethanol and 0.1g of sodium gluconate.

3. Cooling and crystallization: Put the mother liquor treated in step 2 into a super constant temperature water bath, add 2.34g of xylitol micropowder at a temperature of 44°C, and cool down and crystallize for 10 hours.

4. Place at room temperature: Take the massecuite crystallized in step 3 out of the water bath, and place it at room temperature for 16 hours. The massecuite turns white and the crystal grains increase.

5. Freezing and crystallization: Put the massecuite after standing at room temperature in step 4 into a refrigerator at 4°C, and freeze and crystallize for 56 hours.

6. Centrifugation: Centrifuge the frozen crystal massecuite to obtain crystals.

7. Dry the package.

Example 4

1. Pre-concentration: Take 1000 g of the xylitol mother liquor and concentrate it in vacuum to a concentration of 80%.

2. Acceleration of dehydration: When the pre-concentrated massecuite in step 1 is cooled to 46°C, add 4ml of absolute ethanol, 0.2g of sodium gluconate, and 0.07g of potassium sorbate.

3. Cooling and crystallization: put the mother liquor treated in step 2 into a super constant temperature water bath, add 4.44g of xylitol micropowder at a temperature of 46°C, and cool down and crystallize for 26 hours.

4. Place at room temperature: Take the massecuite crystallized in step 3 out of the water bath, and place it at room temperature for 32 hours. The massecuite turns white and the crystal grains increase.

5. Freezing and crystallization: Put the massecuite after standing at room temperature in step 4 into a refrigerator at 4°C, and freeze and crystallize for 38 hours.

6. Centrifugation: Centrifuge the frozen crystal massecuite to obtain crystals.

7. Dry the package.

Claims (1)

1. an Xylitol mother liquor crystallization method is characterized in that on the basis of conventional junction crystal method, having increased dehydration promotion, room temperature placement, three steps of freezing and crystallizing, and has added dewatering agent and promotor, and this crystallization method is made up of following process step:

(1) pre-concentration: with Xylitol mother liquor vacuum concentration to concentration is 75-95%;

(2) dehydration promotes: the cooling of the massecuite behind step 1 pre-concentration is cooled to temperature when being 44-52 ℃; The 0.1-5% that presses massecuite unit weight adds one or both in glycerine, the absolute ethyl alcohol, press the 0.01-0.10% adding Sunmorl N 60S of massecuite dry weight, in the POTASSIUM SORBATE GRANULAR WHITE one or both;

(3) decrease temperature crystalline: the mother liquor with step 2 has been handled well, be put into thermostatic water-circulator bath, 45 ℃ of temperature, the 0.2-0.8% that presses the massecuite dry weight adds xylitol micro powders, decrease temperature crystalline 10-36 hour;

(4) room temperature is placed: the massecuite of step 3 decrease temperature crystalline is taken out water-bath, and room temperature was placed 16-32 hour, and massecuite bleaches, and crystal grain increases;

(5) freezing and crystallizing: step 4 room temperature is placed later massecuite, be put in 4 ℃ of refrigerators freezing and crystallizing 8-72 hour;

(6) centrifugal: the freezing and crystallizing massecuite is centrifugal, obtain crystal;

(7) drying and packaging.