阅读说明：本技术 一种木糖醇母液利用系统及方法 (Xylitol mother liquor utilization system and method ) 是由 程新平 徐开蕾 蔡澄亮 沈峰 安延龙 李勉 于 2020-08-29 设计创作，主要内容包括：本发明涉及一种木糖醇母液利用系统,包括用于对部分待利用的木糖醇母液进行蒸发结晶的降温结晶子系统和用于对含有另一部分待利用的木糖醇母液的木糖醇液勾兑液进行真空结晶的勾兑结晶子系统,部分待利用的木糖醇母液经过降温结晶子系统处理后得到一次木糖醇糖膏和二次木糖醇母液,木糖醇勾兑液经过勾兑结晶子系统处理后得到晶体木糖醇和可再利用的木糖醇母液,在木糖醇勾兑液中除了包含另一部分待利用的木糖醇母液和由降温结晶子系统结晶得到的一次木糖醇糖膏之外,还包括木糖醇氢化液。本发明还公开利用该系统进行木糖醇母液利用方法。本发明设备比较简单,投入成本低,适用于大规模工业化生产,提高晶体木糖醇收率。(The invention relates to a xylitol mother liquor utilization system, which comprises a cooling crystallization subsystem for evaporating and crystallizing partial xylitol mother liquor to be utilized and a blending crystallization subsystem for carrying out vacuum crystallization on xylitol liquor blending liquor containing the other part of the xylitol mother liquor to be utilized, wherein a primary xylitol massecuite and a secondary xylitol mother liquor are obtained after the partial xylitol mother liquor to be utilized is treated by the cooling crystallization subsystem, crystalline xylitol and reusable xylitol mother liquor are obtained after the xylitol blending liquor is treated by the blending crystallization subsystem, and the xylitol blending liquor also comprises a xylitol hydrogenation liquor besides the other part of the xylitol mother liquor to be utilized and the primary xylitol massecuite crystallized by the cooling crystallization subsystem. The invention also discloses a method for utilizing the xylitol mother liquor by utilizing the system. The method has the advantages of simple equipment and low investment cost, is suitable for large-scale industrial production, and improves the yield of the crystal xylitol.)

1. A xylitol mother liquor utilization system is characterized by comprising a cooling crystallization subsystem for evaporating and crystallizing part of xylitol mother liquor to be utilized and a blending crystallization subsystem for vacuum crystallization of xylitol liquor blending liquor containing the other part of the xylitol mother liquor to be utilized, wherein the xylitol blending liquor is temporarily stored in a blending tank, part of the xylitol mother liquor to be utilized is treated by the cooling crystallization subsystem to obtain primary xylitol massecuite and secondary xylitol mother liquor, the primary xylitol massecuite is communicated with the blending tank through a massecuite pipeline, the xylitol blending liquor is treated by the blending crystallization subsystem to obtain crystal xylitol and recyclable xylitol mother liquor, and the recyclable xylitol mother liquor is communicated with a liquid storage tank for storing the xylitol mother liquor to be utilized through a recovery pipeline; the cooling crystallization subsystem comprises a primary evaporating pot, a primary cooling crystallization pot and a primary centrifuge, the blending crystallization subsystem comprises a decoloring pot, an ion exchange column, a filter, an evaporating pot, a vacuum crystallization pot and a centrifuge, and the xylitol blending liquid also comprises xylitol hydrogenation liquid besides xylitol mother liquid to be utilized and primary xylitol massecuite obtained by crystallization of the cooling crystallization subsystem.

2. The xylitol mother liquor utilization system as defined in claim 1, wherein said cooling crystallization subsystem further comprises a secondary cooling crystallization subsystem for evaporating and crystallizing secondary xylitol mother liquor, said secondary cooling crystallization subsystem comprises a secondary evaporation tank, a secondary cooling crystallization tank and a secondary centrifuge, the secondary xylitol mother liquor is processed by the secondary cooling crystallization subsystem to obtain secondary xylitol massecuite and tertiary xylitol mother liquor, and the secondary xylitol massecuite is also communicated with the blending tank through massecuite pipelines.

3. The xylitol mother liquor utilization system as defined in claim 2, wherein said secondary cooling crystallization subsystem further comprises a tertiary cooling crystallization subsystem for evaporating and crystallizing tertiary xylitol mother liquor, said tertiary cooling crystallization subsystem comprises a tertiary evaporation tank, a tertiary cooling crystallization tank and a tertiary centrifuge, the tertiary xylitol mother liquor is processed by the tertiary cooling crystallization subsystem to obtain tertiary xylitol massecuite and quaternary xylitol mother liquor, and the tertiary xylitol massecuite is also communicated with the blending tank through massecuite pipelines.

4. A method for xylitol mother liquor utilization using the xylitol mother liquor utilization system according to claim 1, 2 or 3, characterized by comprising the steps of:

step one, mixing part of xylitol mother liquor to be utilized and xylitol hydrogenation liquor into xylitol blending liquor with stable content;

step two, the mixed xylitol blending liquid is subjected to decoloration, ion exchange, filtration, evaporation, vacuum crystallization and centrifugation in sequence to obtain crystalline xylitol and a recyclable xylitol mother liquid, and the recyclable xylitol mother liquid flows back to a liquid storage tank for storing the xylitol mother liquid to be used for the next time through a recovery pipeline;

thirdly, evaporating the other part of the xylitol mother liquor to be utilized for the first time, cooling and crystallizing for the first time, centrifuging for the first time to obtain primary xylitol massecuite with high content and residual secondary xylitol mother liquor, and enabling the primary xylitol massecuite to enter a blending tank through a massecuite pipeline to be blended with the xylitol mother liquor to be utilized for the next cycle and the xylitol hydrogenated liquid to obtain a next batch of xylitol blending liquid;

and step four, repeating the step one to the step three for the next batch of the xylitol blending liquid until all the xylitol mother liquid to be utilized is treated.

5. The xylitol mother liquor utilization method according to claim 4, wherein the xylitol content of xylitol solution in the xylitol blending liquor is 88-95%.

6. The xylitol mother liquor utilization method according to claim 4, wherein, in the second step, the concentrated xylitol solution after primary evaporation refracts the light to 81-83%.

7. The method for utilizing xylitol mother liquor according to claim 4, wherein in the second step, the time for primary temperature-reducing crystallization is 16 to 18 hours.

8. The method for utilizing xylitol mother liquor according to claim 4, wherein in the second step, the rotation speed of one-time centrifugation is 1500-1800 rpm, and the operation is carried out for 20-30 minutes.

9. The xylitol mother liquor utilization system and the method thereof according to claim 4, further comprising a method for reusing the secondary xylitol mother liquor obtained in the third step, wherein the method comprises the following steps: and (3) sequentially carrying out secondary evaporation, secondary cooling crystallization and secondary centrifugation on the secondary xylitol mother liquor to obtain high-content secondary xylitol massecuite and residual tertiary xylitol mother liquor, and mixing and blending the secondary xylitol massecuite with the xylitol mother liquor to be recycled and the xylitol hydrogenated liquor to be used next time through a massecuite pipeline to obtain the next xylitol blending liquor.

10. The xylitol mother liquor utilization system and method according to claim 9, further comprising a method for reusing the obtained tertiary xylitol mother liquor, the method comprising the steps of: and (3) sequentially carrying out evaporation, cooling crystallization and centrifugation for three times on the three-time xylitol mother liquor for three times to obtain high-content three-time xylitol massecuite and residual four-time xylitol mother liquor, and mixing and blending the three-time xylitol massecuite with the xylitol mother liquor to be recycled and the xylitol hydrogenated liquor to be recycled next time through a massecuite pipeline to obtain the next xylitol blending liquor.

Technical Field

The invention belongs to the technical field of xylitol mother liquor recycling, and particularly relates to a xylitol mother liquor utilization system and method.

Background

Xylitol is a natural sweetener extracted from plant materials such as birch, oak, corn cob, bagasse, etc. A large amount of xylitol mother liquor can be generated in the production of crystal xylitol, the xylitol mother liquor is not easy to obtain crystals due to more impurities and low purity of the xylitol, and the xylitol mother liquor can only be used as liquid xylitol and has lower added value.

The prior art for improving the yield of xylitol mother liquor introduces a method for improving the yield of xylitol as in the patent publication No. CN109678664A, the yield of xylitol in the mother liquor can reach 70 percent by diluting, decoloring, ion-exchange, filtering, concentrating, crystallizing and centrifuging the mother liquor, and the rest xylitol is sold as liquid xylitol. The patent of publication No. CN101810262A discloses a crystallization method of xylitol mother liquor, which is not suitable for large-scale industrial production because three steps of dehydration promotion, room-temperature placement and freezing crystallization are added on the basis of the traditional crystallization method, and a dehydrating agent and a promoter are added. The patent publication No. CN107892644A discloses a method for recovering xylitol from a multi-crystallization xylitol mother solution, which comprises the steps of diluting the xylitol mother solution to 10-20% of the mass of the solution, performing ultrafiltration, concentrating to a mass percent concentration of 80-85% to obtain a concentrated xylitol mother solution, and performing cooling crystallization and recrystallization to obtain xylitol crystals.

Disclosure of Invention

The invention aims to solve the technical problem of providing a xylitol mother liquor utilization system and a method, and improving the yield of crystal xylitol.

The invention is realized in such a way, and provides a xylitol mother liquor utilization system, which comprises a cooling crystallization subsystem for evaporating and crystallizing part of the xylitol mother liquor to be utilized and a blending crystallization subsystem for vacuum crystallization of xylitol liquor blending liquor containing the other part of the xylitol mother liquor to be utilized, wherein the xylitol blending liquor is temporarily stored in a blending tank, part of the xylitol mother liquor to be utilized is treated by the cooling crystallization subsystem to obtain primary xylitol massecuite and secondary xylitol mother liquor, the primary xylitol massecuite is communicated with the blending tank through a massecuite pipeline, the xylitol blending liquor is treated by the blending crystallization subsystem to obtain crystal xylitol and recyclable xylitol mother liquor, and the recyclable xylitol mother liquor is communicated with a liquid storage tank for storing the xylitol mother liquor to be utilized through a recovery pipeline; the cooling crystallization subsystem comprises a primary evaporating pot, a primary cooling crystallization pot and a primary centrifuge, the blending crystallization subsystem comprises a decoloring pot, an ion exchange column, a filter, an evaporating pot, a vacuum crystallization pot and a centrifuge, and the xylitol blending liquid also comprises xylitol hydrogenation liquid besides xylitol mother liquid to be utilized and primary xylitol massecuite obtained by crystallization of the cooling crystallization subsystem.

The invention is realized in such a way that the method for utilizing the xylitol mother liquor by using the xylitol mother liquor utilization system comprises the following steps:

step one, mixing part of xylitol mother liquor to be utilized and xylitol hydrogenation liquor into xylitol blending liquor with stable content;

step two, the mixed xylitol blending liquid is subjected to decoloration, ion exchange, filtration, evaporation, vacuum crystallization and centrifugation in sequence to obtain crystalline xylitol and a recyclable xylitol mother liquid, and the recyclable xylitol mother liquid flows back to a liquid storage tank for storing the xylitol mother liquid to be used for the next time through a recovery pipeline;

thirdly, evaporating the other part of the xylitol mother liquor to be utilized for the first time, cooling and crystallizing for the first time, centrifuging for the first time to obtain primary xylitol massecuite with high content and residual secondary xylitol mother liquor, and enabling the primary xylitol massecuite to enter a blending tank through a massecuite pipeline to be blended with the xylitol mother liquor to be utilized for the next cycle and the xylitol hydrogenated liquid to obtain a next batch of xylitol blending liquid;

and step four, repeating the step one to the step three for the next batch of the xylitol blending liquid until all the xylitol mother liquid to be utilized is treated.

Compared with the prior art, the xylitol mother liquor utilization system and the method have the following characteristics:

(1) the yield of the crystal xylitol is greatly improved, and the yield of the crystal xylitol obtained by the method is more than or equal to 90 percent;

(2) the process has the advantages of simple equipment and low investment cost, and is suitable for large-scale industrial production.

Drawings

FIG. 1 is a schematic structural diagram of a preferred embodiment of the xylitol mother liquor utilization system of the present invention;

FIG. 2 is a schematic diagram showing the principle of the xylitol mother liquor utilization method of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, the preferred embodiment of the xylitol mother liquor utilization system of the present invention comprises a cooling crystallization subsystem 1 for evaporating and crystallizing a portion of the xylitol mother liquor a to be utilized, and a blending crystallization subsystem 2 for vacuum crystallizing a xylitol liquor blending liquor B containing another portion of the xylitol mother liquor to be utilized. The xylitol blending liquid B is temporarily stored in a blending tank (not shown in the figure). The arrows in the figure indicate the direction in which the material is moving. Part of the xylitol mother liquor A to be utilized is treated by a cooling crystallization subsystem 1 to obtain primary xylitol massecuite C and secondary xylitol mother liquor D, and the primary xylitol massecuite C is communicated with a blending tank through a massecuite pipeline 3. The xylitol blending liquid B is treated by a blending crystallization subsystem 2 to obtain crystal xylitol K and a recyclable xylitol mother liquid, and the recyclable xylitol mother liquid is communicated with a liquid storage tank (not shown in the figure) for storing the xylitol mother liquid A to be used through a recovery pipeline 4.

The cooling crystallization subsystem 1 comprises a primary evaporation tank 11, a primary cooling crystallization tank 12 and a primary centrifuge 13. The blending crystallization subsystem 2 comprises a decoloring tank 5, an ion exchange column 6, a filter 7, an evaporation tank 8, a vacuum crystallization tank 9 and a centrifuge 10. The xylitol blending liquid B comprises xylitol mother liquor A to be utilized and primary xylitol massecuite C obtained by crystallization of the cooling crystallization subsystem 2, and also comprises xylitol hydrogenation liquid E.

The xylitol mother liquor A to be utilized is derived from the xylitol mother liquor obtained after the centrifugal process in the production process of the xylitol crystal. The xylitol hydrogenation liquid E is derived from xylitol hydrogenation liquid in the production process of xylitol crystals.

A small amount of the xylitol mother liquor A to be utilized is utilized by the blending crystallization subsystem 2, and most of the xylitol mother liquor A to be utilized is utilized by the cooling crystallization subsystem 1.

The cooling crystallization subsystem 2 also comprises a secondary cooling crystallization subsystem for evaporating and crystallizing the secondary xylitol mother liquor D. The secondary cooling crystallization subsystem comprises a secondary evaporation tank 14, a secondary cooling crystallization tank 15 and a secondary centrifuge 16. And the secondary xylitol mother liquor D is treated by a secondary cooling crystallization subsystem to obtain secondary xylitol massecuite F and tertiary xylitol mother liquor G, and the secondary xylitol massecuite F is also communicated with the blending tank through a massecuite pipeline 3.

The secondary cooling crystallization subsystem also comprises a tertiary cooling crystallization subsystem for evaporating and crystallizing the tertiary xylitol mother liquor G. The tertiary temperature-reducing crystallization subsystem comprises a tertiary evaporation tank 17, a tertiary temperature-reducing crystallization tank 18 and a tertiary centrifuge 19. And the third xylitol mother liquor G is treated by a third cooling crystallization subsystem to obtain a third xylitol massecuite H and a fourth xylitol mother liquor J, and the third xylitol massecuite H is also communicated with the blending tank through a massecuite pipeline 3.

Referring to fig. 2, the invention also discloses a method for utilizing the xylitol mother liquor by using the xylitol mother liquor utilization system, which comprises the following steps:

step one, mixing part of xylitol mother liquor A to be utilized and xylitol hydrogenation liquor E into xylitol blending liquor B with stable content.

And step two, the mixed xylitol blending liquid B is subjected to decoloration, ion exchange, filtration, evaporation, vacuum crystallization and centrifugation in sequence to obtain crystal xylitol K and recyclable xylitol mother liquid, and the recyclable xylitol mother liquid flows back to a liquid storage tank for storing the xylitol mother liquid A to be recycled through a recovery pipeline 4 to be recycled.

And step three, carrying out primary evaporation, primary cooling crystallization and primary centrifugation on the other part of the xylitol mother liquor A to be utilized to obtain primary xylitol massecuite C with high content and residual secondary xylitol mother liquor D, wherein the primary xylitol massecuite C enters a blending tank through a massecuite pipeline 3 to be blended with the xylitol mother liquor A to be utilized next in circulation and the xylitol hydrogenation liquor E to obtain a next batch of xylitol blending liquor B.

And step four, repeating the step one to the step three for the next batch of the xylitol blending liquid B until the xylitol mother liquid A to be utilized is completely processed.

The xylitol content of xylitol solution in the xylitol blending solution B is 88-95%.

In the second step, the refraction of the xylitol concentrated solution after the primary evaporation is 81 to 83 percent. The time of primary cooling crystallization is 16-18 hours. The rotating speed of one-time centrifugation is 1500-1800 revolutions per minute, and the operation time is 20-30 minutes.

The xylitol mother liquor utilization method also comprises a method for reusing the secondary xylitol mother liquor D obtained in the third step, and the method comprises the following steps: and sequentially carrying out secondary evaporation, secondary cooling crystallization and secondary centrifugation on the secondary xylitol mother liquor D to obtain high-content secondary xylitol massecuite F and residual tertiary xylitol mother liquor G. And (3) feeding the secondary xylitol massecuite F into a blending tank through a massecuite pipeline 3, and blending with the xylitol mother liquor A and the xylitol hydrogenated liquor E to be recycled next time to obtain a next batch of xylitol blending liquor B.

The xylitol mother liquor utilization method also comprises a method for reusing the obtained tertiary xylitol mother liquor G, and the method comprises the following steps: and (3) sequentially carrying out evaporation, cooling crystallization and centrifugation for three times on the third xylitol mother liquor G for three times to obtain a high-content third xylitol massecuite H and a residual fourth xylitol mother liquor J, wherein the third xylitol massecuite H enters a blending tank through a massecuite pipeline 3 to be blended with the xylitol mother liquor A and the xylitol hydrogenation liquor E to be recycled next time, so as to obtain a next xylitol blending liquor B.

The quartic xylitol mother liquor J is treated and utilized as liquid xylitol.

The xylitol mother liquor utilization method can fully utilize the xylitol mother liquor generated in the prior xylitol crystal production process, improve the utilization value of the xylitol mother liquor and integrally improve the crystal xylitol yield.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.