Acesulfame-k crystal and a method for preparing the same

Abstract

The application discloses a kind of anhydrous dextrose crystals and preparation method thereof, belong to anhydrous dextrose production technical field.The preparation method includes the following steps: (1) to anhydrous dextrose crude product solution active carbon and crystallizing agent are added and are decolorized and are cooked, after filtration, obtain decolorized material liquid;(2) the decolorized material liquid obtained in step (1) is cooled and crystallized, obtain crystal-containing material liquid;(3) the crystal-containing material liquid obtained in step (2) is secondary crystallized, centrifuged, dried, obtain anhydrous dextrose crystal.The application can improve the ratio of 30-80 mesh particles in anhydrous dextrose crystal by controlling the type, amount, cooling rate and other operation conditions of crystallizing agent optimization, the prepared anhydrous dextrose crystal particle size is higher than 90% in 30-80 mesh particles, meet the needs of customers, and once can reach the particle size requirement, without rework, shorten the production cycle, avoid material loss, reduce production cost.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of acesulfame production, and particularly relates to acesulfame crystal and a preparation method thereof. BACKGROUND

[0002] In the decoloring and refining section of acesulfame, a certain amount of heavy sugar (obtained by recrystallization of secondary concentrated sugar water) is first put into a decoloring cooking kettle, then a decoloring mother liquor (obtained after refining centrifugation) is added according to a certain solid-liquid ratio, and finally activated carbon is added according to a proportion, and a decoloring circulating pump and steam are used for decoloring cooking operation; after the decoloring cooking is completed, the material is punched into a coarse filter for filtration, the filtrate after filtration is punched into a fine filter in the refining section for filtration, and after filtration, the material is subjected to stepwise cooling in a pre-cooling kettle and a freezing kettle, and after cooling is completed, centrifugal separation and drying are performed to obtain a semi-finished product. The market currently has certain requirements for the particle size of acesulfame crystal, and therefore controlling the particle size range of acesulfame crystal is the key to acesulfame production.

[0003] Patent CN112574139A discloses a crystallization method of fine powder acesulfame, which comprises configuring acesulfame crude product into a solution with a concentration of 880-1000 g / L, heating and dissolving, and then filtering and entering a pre-cooling kettle; after the material enters the pre-cooling kettle, the temperature is reduced to 70-75℃, and the material is transferred to a freezing kettle; after the material is transferred to the freezing kettle, the stirring speed of the freezing kettle is adjusted to 33-35 HZ, the freezing kettle salt water valve is opened after 20-30 minutes, the material is cooled to 15-20℃, and the material is centrifugally separated and dried. The obtained acesulfame crystal has a particle size of 20-40 mesh, and the particle size of 40-100 mesh accounts for 75-80%.

[0004] Patent CN106496159A discloses a production process of acesulfame large particle crystal, which comprises the following steps: configuring acesulfame mother liquor with a mass concentration of 5-55%, and heating to 85-100℃; adding the mother liquor into a crystallizer, and cooling in three stages, continuously stirring in the process to enable the crystal and the liquid to fully contact; first stage cooling: cooling from 85-100℃ to 70-80℃ at a cooling rate of 5-8℃ / h; second stage cooling: cooling from 70-80℃ to 30-45℃ at a cooling rate of 8-12℃ / h; third stage cooling: cooling from 30-45℃ to 3-10℃ at a cooling rate of 12-18℃ / h; stopping cooling of the mother liquor, and continuing to stir for at least 30 min; and adding into a centrifuge for centrifugation and drying. The production process of acesulfame large particle crystal can make the particle size of acesulfame crystal above 100 mesh reach 95% or more.

[0005] The above method can obtain target acesulfame, but some customers require that the proportion of acesulfame crystals of 30-80 mesh particles is greater than 90%, and the product on the market has a proportion of 30-80 mesh particles of about 75%, which is far from meeting the needs of customers, and needs to be further screened through a screen to obtain the required mesh number, and the remaining acesulfame crystals that do not meet the requirements of customers are put into the decoloring section again for rework, which causes a material loss of about 15% each time, resulting in a large amount of waste. SUMMARY

[0006] The present application aims at the deficiencies of the prior art, and provides a preparation method of acesulfame crystals, so that the proportion of 30-80 mesh particles in the prepared acesulfame crystals is greater than 90%, and the material rework is not needed, thereby reducing the production cost.

[0007] To achieve the above object, the technical scheme adopted by the present application is as follows.

[0008] A preparation method of acesulfame crystals, comprising the following steps:

[0009] (1) adding activated carbon and a crystallization agent into acesulfame crude solution to perform decoloring and material boiling, and then filtering to obtain a decoloring material solution;

[0010] (2) cooling and crystallizing the decoloring material solution obtained in step (1) to obtain a crystal-containing material solution;

[0011] (3) performing secondary crystallization on the crystal-containing material solution obtained in step (2), centrifuging, and drying to obtain acesulfame crystals.

[0012] The acesulfame crude solution in step (1) of the present application is composed of reconstituted sugar and a decoloring mother liquor, wherein the concentration of the acesulfame crude solution is 880-1000 g / L.

[0013] The activated carbon in step (1) of the present application is added in an amount of 0.15%-0.25% of the mass of the reconstituted sugar; preferably 0.17-0.2%.

[0014] The crystallization agent in step (1) of the present application is ethanol, and the crystallization agent is added in an amount of 9%-11% of the mass of the reconstituted sugar; preferably 10%.

[0015] The decoloring and material boiling in step (1) of the present application is performed under the following conditions: the steam pressure is 0.15-0.2 MPa, and the temperature is 85-90℃.

[0016] The cooling and crystallization in step (2) of the present application is performed under the following conditions: the solution is cooled at a speed of 3-5℃ / h for 3-4 h, and then stirred at a speed of 80-200 r / min for at least 30 min.

[0017] Preferably, the cooling crystallization condition is that the temperature is lowered at a speed of 3.5-4.5℃ / h for 3-3.5h, and then stirred at a speed of 95-105r / min for 30-40min.

[0018] Most preferably, the speed is 100r / min.

[0019] The secondary crystallization in the step (3) is that the temperature is lowered at a speed of 5-7℃ / h to 15-20℃ while stirring.

[0020] Preferably, the temperature lowering in the secondary crystallization is that the temperature is lowered at a speed of 5.5-6.5℃ / h to 15-17℃.

[0021] Preferably, the stirring speed in the step (3) is 80-200r / min, further preferably 95-105r / min, and most preferably 100r / min.

[0022] The particle size range of the acesulfame-K crystal in the step (3) is that the proportion of 30-80mesh particles is more than 90%.

[0023] The present application also provides the acesulfame-K crystal prepared by the above preparation method, wherein the particle size range of the acesulfame-K crystal is that the proportion of 30-80mesh particles is more than 90%.

[0024] The heavy sugar and the decolorized mother liquor in the present application are defined as conventional in the art, such as CN112574139B, specifically, the heavy sugar is a product obtained by secondary concentration of sugar water and then recrystallization of the heavy sugar, and the decolorized mother liquor is a product obtained after refining and centrifugation.

[0025] Compared with the prior art, the present application has the following beneficial effects:

[0026] (1) The proportion of 30-80mesh particles in the acesulfame-K crystal prepared by the original acesulfame-K crystallization method is about 75%, and the present application can improve the proportion of 30-80mesh particles in the acesulfame-K crystal by optimizing the operation conditions such as the type and amount of the crystallization agent and the cooling rate, so that the proportion of 30-80mesh particles in the prepared acesulfame-K crystal is more than 90%, which meets the customer's demand.

[0027] (2) The present application can directly and quickly meet the requirement that the proportion of 30-80mesh particles in the acesulfame-K crystal is more than 90%, and the particle size requirement can be met at one time without rework, which shortens the production cycle, avoids material loss, and reduces production cost. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The figure is a schematic diagram of the equipment used in the preparation method of the acesulfame-K crystal of the present application. DETAILED DESCRIPTION

[0029] The following non-limiting examples can provide a more complete understanding of the application to those of ordinary skill in the art, but are not intended in any way to limit the scope of the application. The following merely illustrates the scope of the application claimed, and those skilled in the art can make many changes and modifications to the application disclosed without departing from the scope of the application claimed.

[0030] The application is further described in the following specific examples. The various chemical reagents used in the examples are obtained by conventional commercial routes unless otherwise specified.

[0031] The Acesulfame-K crystal and the preparation method thereof described in the application can be prepared by using conventional equipment in the art, i.e. Figure 1 As shown in the figure, the equipment includes, in series, a decolorizing boiling kettle, a material pumping device, a rough filter, a fine filter, a pre-cooling kettle, a freezing kettle and a refining centrifuge.

[0032] Example 1

[0033] The preparation method of the Acesulfame-K crystal includes the following steps:

[0034] (1) 2200 kg of heavy sugar, 2.2 m 3 The decolorizing mother liquor and 5 kg of activated carbon are mixed, and then 220 kg of ethanol is added. The decolorizing stirring and steam are turned on to perform decolorizing boiling. The steam pressure is 0.15 MPa. After the material temperature is boiled to 85℃, the steam valve is closed, and the decolorizing material pumping device is started to pump the material into the rough filter and the fine filter in sequence for filtration. The filtered decolorizing material liquid enters the pre-cooling kettle.

[0035] (2) After the decolorizing material liquid enters the pre-cooling kettle, the pre-cooling kettle circulating water valve is opened to cool the material. The cooling rate is maintained at 3.5℃ / h. The solution is left to stand for 3 h to allow the crystals to gradually form and grow. At the same time, the pre-cooling kettle stirring is turned on to fully stir the solution. The stirring speed is 100 r / min, and the stirring time is 30 min to obtain a crystal-containing material liquid.

[0036] (3) The crystal-containing material liquid passes to the freezing kettle. The cooling rate is maintained at 5.5℃ / h, and the stirring speed of the freezing kettle is 100 r / min. When the temperature of the material liquid is reduced to 15℃, it is sent to the refining centrifuge for centrifugal separation and drying to obtain the Acesulfame-K crystal. The Acesulfame-K crystal obtained has a particle size of 30-80 μm, and the proportion of the particles is 93.7%.

[0037] Example 2

[0038] The preparation method of the Acesulfame-K crystal includes the following steps:

[0039] (1) into the decoloring cooking kettle 2800kg heavy sugar, 2.7m 3 The decoloring mother liquor and 5kg activated carbon were mixed, then 252kg ethanol was added, the decoloring stirring and steam were started to carry out the decoloring cooking, the steam pressure was 0.20MPa; after the material temperature was boiled to 90℃, the steam valve was closed, the decoloring pump was started to pump the material into the rough filter and the fine filter in sequence to carry out the filtration, the filtered decoloring material liquid entered the pre-cooling kettle;

[0040] (2) after the decoloring material liquid entered the pre-cooling kettle, the pre-cooling kettle circulating water valve was opened to cool the material, the cooling rate was kept at 4.5℃ / h, the solution was left for 3.5h to let the crystals gradually form and grow, and at the same time the pre-cooling kettle stirring was started to fully stir the solution, the stirring speed was 100r / min, the stirring time was 40min, the crystal-containing material liquid was obtained;

[0041] (3) the crystal-containing material liquid passed to the freezing kettle, the cooling rate was kept at 6.0℃ / h, the freezing kettle stirring speed was 100r / min, when the material liquid temperature was reduced to 17℃, it was sent to the refining centrifuge to carry out the centrifugal separation and drying, thus the acesulfame potassium crystal was obtained. The 30-80 mesh particles in the obtained acesulfame potassium crystal accounted for 94.2%.

[0042] Example 3

[0043] The preparation method of the acesulfame potassium crystal comprises the following steps:

[0044] (1) into the decoloring cooking kettle 2500kg heavy sugar, 2.5m 3 The decoloring mother liquor and 5kg activated carbon were mixed, then 262kg ethanol was added, the decoloring stirring and steam were started to carry out the decoloring cooking, the steam pressure was 0.18MPa; after the material temperature was boiled to 92℃, the steam valve was closed, the decoloring pump was started to pump the material into the rough filter and the fine filter in sequence to carry out the filtration, the filtered decoloring material liquid entered the pre-cooling kettle;

[0045] (2) after the decoloring material liquid entered the pre-cooling kettle, the pre-cooling kettle circulating water valve was opened to cool the material, the cooling rate was kept at 3.5℃ / h, the solution was left for 3.5h to let the crystals gradually form and grow, and at the same time the pre-cooling kettle stirring was started to fully stir the solution, the stirring speed was 100r / min, the stirring time was 35min, the crystal-containing material liquid was obtained;

[0046] (4) the crystal-containing material liquid passed to the freezing kettle, the cooling rate was kept at 6.5℃ / h, the freezing kettle stirring speed was 100r / min, when the material liquid temperature was reduced to 16℃, it was sent to the refining centrifuge to carry out the centrifugal separation and drying, thus the acesulfame potassium crystal was obtained. The 30-80 mesh particles in the obtained acesulfame potassium crystal accounted for 94.6%.

[0047] Comparative Example 1

[0048] The preparation method of acesulfame potassium crystal, the difference between the present example and example 1 is that the added amount of ethanol is 8% of the mass of the heavy sugar, and the conditions of the cooling crystallization are different.

[0049] Specifically, the following steps are included:

[0050] (1) 2200 kg of heavy sugar, 2.2 m 3 The decolorization mother liquor and 5 kg of activated carbon are mixed, then 176 kg of ethanol is added, the decolorization stirring and steam are started for decolorization cooking, the steam pressure is 0.15 MPa, after the material temperature is cooked to 85℃, the steam valve is closed, the decolorization material pump is started to pump the material into the coarse filter and the fine filter in sequence for filtration, and the filtered decolorization material liquid enters the pre-cooling kettle;

[0051] (2) After the decolorization material liquid enters the pre-cooling kettle, the pre-cooling kettle circulating water valve is opened to cool the material, the cooling rate is maintained at 8℃ / h, the solution is left to stand for 3 h to allow the crystals to gradually form and grow, and at the same time the pre-cooling kettle stirring is started to fully stir the solution, the stirring speed is 50 r / min, and the stirring time is 60 min, to obtain a crystal-containing material liquid;

[0052] (3) The crystal-containing material liquid is transferred to the freezing kettle, the cooling rate is maintained at 5.5℃ / h, the stirring speed of the freezing kettle is 100 r / min, when the material liquid temperature is reduced to 15℃, it is sent to the refining centrifuge for centrifugal separation and drying, and acesulfame potassium crystal is obtained. The particle size of 30-80 of the obtained acesulfame potassium crystal accounts for 77.5%.

[0053] Example 2

[0054] The preparation method of acesulfame potassium crystal, the difference between the present example and example 1 is that the added amount of ethanol is 8% of the mass of the heavy sugar, and the conditions of the cooling crystallization are different.

[0055] Specifically, the following steps are included:

[0056] (1) 2200 kg of heavy sugar, 2.2 m 3 The decolorization mother liquor and 5 kg of activated carbon are mixed, then 176 kg of ethanol is added, the decolorization stirring and steam are started for decolorization cooking, the steam pressure is 0.15 MPa, after the material temperature is cooked to 85℃, the steam valve is closed, the decolorization material pump is started to pump the material into the coarse filter and the fine filter in sequence for filtration, and the filtered decolorization material liquid enters the pre-cooling kettle;

[0057] (2) After the decolorizing liquid enters the precooling kettle, the circulating water valve of the precooling kettle is opened to cool the material. The cooling rate is maintained at 3.5℃ / h. The solution is left to stand for 3h to allow the crystals to gradually form and grow. At the same time, the precooling kettle is turned on to stir the solution. The stirring speed is 100r / min and the stirring time is 30min to obtain the liquid containing crystals.

[0058] (3) The crystalline liquid is transferred to a freezing reactor, and the cooling rate is maintained at 3℃ / h. The stirring speed of the freezing reactor is 300r / min. When the temperature of the liquid drops to 15℃, it is sent to a refining centrifuge for centrifugal separation and drying to obtain acesulfame crystals. The proportion of 30-80 mesh particles in the obtained acesulfame crystals is 74.9%.

[0059] Comparative Example 3

[0060] The preparation method of acesulfame K crystals differs from that of Example 1 in that 220 kg of hydrogen peroxide is used instead of ethanol, and in step (3), when the temperature of the liquid material drops to 10°C, it is sent to a refining centrifuge for centrifugal separation and drying.

[0061] Specifically, the steps include the following:

[0062] (1) Add 2200kg of reconstituted sugar and 2.2m of [unclear text] to the decolorizing cooking vessel. 3 Mix the decolorizing mother liquor with 5 kg of activated carbon, then add 220 kg of hydrogen peroxide, turn on the decolorizing stirring and steam to decolorize and cook the material. The steam pressure is 0.15 MPa. After the material temperature reaches 85℃, close the steam valve and start the decolorizing feeding pump to pump the material into the coarse filter and fine filter in sequence for filtration. The filtered decolorized liquid enters the precooling kettle.

[0063] (2) After the decolorizing liquid enters the precooling kettle, the circulating water valve of the precooling kettle is opened to cool the material. The cooling rate is maintained at 3.5℃ / h. The solution is left to stand for 3h to allow the crystals to gradually form and grow. At the same time, the precooling kettle is turned on to stir the solution. The stirring speed is 100r / min and the stirring time is 30min to obtain the liquid containing crystals.

[0064] (3) The crystalline liquid is transferred to a freezing reactor and cooled at a rate of 5.5℃ / h. The stirring speed of the freezing reactor is 100r / min. When the temperature of the liquid drops to 10℃, it is sent to a refining centrifuge for centrifugal separation and drying to obtain acesulfame crystals. The proportion of 30-80 mesh particles in the obtained acesulfame crystals is 73.7%.

[0065] Comparative Example 4

[0066] The preparation method of acesulfame potassium crystals differs from that of Example 1 in that ethanol is not added, and crystallization is carried out according to the method of CN112574139A.

[0067] Specifically comprising the following steps:

[0068] (1) into the decoloring kettle 2200 kg of heavy sugar, 2.5 m 3 The decoloring mother liquor and 5 kg of activated carbon, open the decoloring stirring and steam to carry out decoloring cooking, the steam pressure is 0.15 MPa; the material temperature is boiled to 85℃, then close the steam valve, start the decoloring pump to pump the material into the coarse filter and fine filter in turn for filtration, after filtration into the pre-cooling kettle;

[0069] (2) after the material enters the pre-cooling kettle, open the pre-cooling kettle circulating water valve to cool the material, when the temperature drops to 75℃, transfer the material to the freezing kettle, and adjust the stirring speed of the freezing kettle to 33HZ;

[0070] (3) after the material enters the freezing kettle for 30 min, open the freezing kettle brine valve to cool the material, when the material temperature drops to 15℃, send to the refining centrifuge for centrifugal separation and drying, to obtain the acesulfame-K crystal. The 30-80 mesh particles in the obtained acesulfame-K crystal account for 72.2%.

[0071] The above description of the embodiments is to facilitate the ordinary skilled person in the art to understand and use the invention. Those skilled in the art can easily make various modifications to these embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications made by those skilled in the art according to the disclosure of the present application without departing from the scope of the present application should be within the scope of protection of the present application.

Claims

1. A method for preparing acesulfame potassium crystals, characterized in that, Includes the following steps: (1) Add activated carbon and crystallizing agent to the crude acesulfame potassium solution for decolorization and boiling. After filtration, the decolorized liquid is obtained. (2) The decolorizing solution obtained in step (1) is cooled and crystallized to obtain a solution containing crystals; (3) The crystalline liquid obtained in step (2) is subjected to secondary crystallization, centrifuged and dried to obtain acesulfame crystals; The crude acesulfame potassium solution in step (1) is composed of reconstituted sugar and decolorizing mother liquor, wherein the concentration of the crude acesulfame potassium solution is 880-1000 g / L; The crystallizing agent mentioned in step (1) is ethanol, and the amount of crystallizing agent added is 9%-11% of the mass of the reconstituted sugar; The cooling crystallization conditions described in step (2) are: after cooling for 3-4 hours at a rate of 3-5℃ / h, stir at a speed of 80-200r / min for at least 30 minutes; The secondary crystallization described in step (3) is as follows: while stirring, the temperature is lowered to 15-20℃ at a rate of 5-7℃ / h.

2. The preparation method according to claim 1, characterized in that, The amount of activated carbon added in step (1) is 0.15%-0.25% of the mass of the reconstituted sugar.

3. The preparation method according to claim 1, characterized in that, The amount of activated carbon added in step (1) is 0.17-0.2% of the mass of the reconstituted sugar.

4. The preparation method according to claim 1, characterized in that, The amount of crystallizing agent added in step (1) is 10% of the mass of the reconstituted sugar.

5. The preparation method according to claim 1, characterized in that, The conditions for decolorizing and cooking the material in step (1) are: steam pressure of 0.15-0.2MPa and temperature of 85-90℃.

6. The preparation method according to claim 1, characterized in that, The cooling crystallization conditions described in step (2) are as follows: cool the mixture at a rate of 3.5-4.5℃ / h for 3-3.5h, and then stir it at a speed of 95-105r / min for 30-40min.

7. The preparation method according to claim 1, characterized in that, The secondary crystallization mentioned in step (3) is as follows: while stirring, the temperature is reduced to 15-17℃ at a rate of 5.5-6.5℃ / h.

8. The preparation method according to claim 7, characterized in that, The stirring speed in step (3) is 80-200 r / min.

9. The preparation method according to claim 7, characterized in that, The stirring speed in step (3) is 95-105 r / min.

10. The preparation method according to any one of claims 1-9, characterized in that, The particle size range of acesulfame K crystals mentioned in step (3) is: 30-80 mesh particles account for >90%.

11. An acesulfame K crystal prepared by the preparation method according to any one of claims 1-10, characterized in that, The particle size range of the acesulfame K crystals is: 30-80 mesh particles account for >90%.

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