Xylitol preparation device integrating evaporation, crystallization and centrifugal separation and control method thereof

Patent metadata

Field	Value
Publication number	US-11840501-B2
Application number	US-202017288020-A
Country	US
Kind code	B2
Filing date	Mar 13, 2020
Priority date	Mar 18, 2019
Publication date	Dec 12, 2023
Grant date	Dec 12, 2023

Abstract

The present invention relates to a xylitol preparation device integrating evaporation, crystallization and centrifugation, including a xylitol tank, a cleaning liquid tank, a recycling tank and a multiple distribution system, wherein the multiple distribution system includes J groups of evaporators for evaporation concentration, K groups of vacuum crystallization kettles for vacuum crystallization and L groups of centrifuges for centrifugation, wherein 2≤J≤6, 6≤K≤12 and 2≤L≤4; the evaporator, the vacuum crystallization kettle and the centrifuge in different groups are sequentially connected in series with one another through a pipeline and a valve respectively; by controlling on and off of each valve, a xylitol exchange liquid is switched and controlled between a series-connection mode and a parallel-connection mode in the multiple distribution system to enable evaporation, crystallization and separation processes to reach an optimal effect distribution so as to improve productivity. The present invention further discloses a control method of the device. The processes and equipment of the present invention are highly integrated to realize continuous integrated production of xylitol preparation with low energy consumption and high automation degree, and full utilization of raw materials.

First claim

The invention claimed is:

1. A xylitol preparation device integrating evaporation, crystallization and centrifugation, comprising a xylitol tank, a cleaning liquid tank, a recycling tank, and a multiple distribution system,
wherein the multiple distribution system comprises J groups of evaporators for evaporation-concentrating a xylitol exchange liquid to be treated into a xylitol concentrate, K groups of vacuum crystallization kettles for obtaining a xylitol paste by vacuum-crystallizing the xylitol concentrate, and L groups of centrifuges for obtaining a xylitol crystal by centrifuging the xylitol paste, wherein 2≤J≤6, 6≤K≤12 and 2≤L≤4;
inlets and outlets of the evaporator, the vacuum crystallization kettle and the centrifuge in different groups are sequentially connected in series with one another through a pipeline and a valve respectively, inlets and outlets of the evaporators in J groups are connected in parallel with each other through a pipeline respectively, inlets and outlets of the vacuum crystallization kettles in K groups are connected in parallel with each other through a pipeline respectively, inlets and outlets of the centrifuges in L groups are connected in parallel with each other through a pipeline respectively, the inlet of each evaporator in J groups is in communication with a main pipeline holding the xylitol exchange liquid to be treated through a pipeline and a valve respectively, and the outlet of each centrifuge in L groups is in communication with the xylitol tank, the cleaning liquid tank and the recycling tank through a pipeline and a valve respectively;
the xylitol tank is configured to collect the prepared xylitol crystal, the cleaning liquid tank is configured to collect cleaning liquid from cleaning the evaporators, the vacuum crystallization kettles and the centrifuges respectively, and the recycling tank is configured to collect the xylitol paste that is not converted into the xylitol crystal during centrifugation; and
the multiple distribution system is configured to switch the xylitol exchange liquid between a series-connection working mode and a parallel-connection working mode by controlling on and off of each valve.

2. The xylitol preparation device according to claim 1 , wherein the device is configured to transport the xylitol paste that is collected by the recycling tank and not converted into the xylitol crystal to the inlet of J groups of evaporators and the main pipeline holding the xylitol exchange liquid to be treated through an additionally-disposed pipeline, an additionally-disposed valve and a circulation pump disposed in the pipeline so as to be mixed with the xylitol exchange liquid pro rata.

3. The xylitol preparation device according to claim 1 , wherein the device is configured to transport the cleaning liquid collected in the cleaning liquid tank to the main pipeline holding the xylitol exchange liquid to be treated through an additionally-disposed pipeline, an additionally-disposed valve and a cleaning liquid transport pump disposed in the pipeline so as to be mixed with the xylitol exchange liquid pro rata.

4. A method of operating the xylitol preparation device according to any one of claim 1 , comprising the following steps:
transporting the xylitol exchange liquid to be treated, through the main pipeline, into the multiple distribution system;
obtaining the xylitol concentrate by performing evaporation concentration in the J groups of evaporators;
obtaining the xylitol paste by performing vacuum crystallization in the K groups of vacuum crystallization kettles;
obtaining the xylitol crystal by performing centrifugation in the L groups of centrifuges; and
transporting the xylitol crystal into the xylitol tank for storage;
wherein the xylitol paste that is not converted into the xylitol crystal during centrifugation is transported into the recycling tank for temporary recovery and then to the inlet of J groups of evaporators and the main pipeline holding the xylitol exchange liquid to be treated through the additionally-disposed pipeline, the additionally-disposed valve and the circulation pump disposed in the pipeline, so as to be mixed with the xylitol exchange liquid pro rata; and
the cleaning liquid from cleaning the evaporators, the vacuum kettles and the centrifuges is collected in the cleaning liquid tank for temporary storage through the pipeline and transported to the main pipeline holding the xylitol exchange liquid to be treated through the additionally-disposed pipeline, the additionally-disposed valve and the cleaning liquid transport pump disposed in the pipeline, so as to be mixed with the xylitol exchange liquid pro rata.

5. The method according to claim 4 , further comprising the following step:
mixing the xylitol paste that is transported by the circulation pump and not converted into the xylitol crystal with the xylitol exchange liquid in the main pipeline at a ratio of 1:4 for reuse; and
mixing the cleaning liquid transported by the cleaning liquid transport pump with the xylitol exchange liquid in the main pipeline at a ratio of 1:8 for reuse.

6. The method according to claim 4 , wherein the xylitol exchange liquid to be treated is pre-treated through a coarse filtration process and/or a fine filtration process respectively to remove solid particle impurities;
in the coarse filtration process, coarse particle impurities are removed from the xylitol exchange liquid by adopting a filter element with a pore size of 0.45 μm, and a pressure difference during the coarse filtration is controlled between 0.1 MPa and 0.4 MPa; and
in the fine filtration process, fine particle impurities are removed from the xylitol exchange liquid by adopting a filter element with a pore size of 0.22 μm, and a pressure difference during the fine filtration is controlled between 0.1 MPa and 0.4 MPa.

7. The method according to claim 4 , wherein a transmittance of the xylitol exchange liquid to be treated is 95% or more, a PH value is 5.0-7.5, and a preheating temperature is controlled to 90° C.-100° C.; a refractive index of the xylitol concentrate is 75%-83%, and a temperature is controlled to 55° C.-75° C.

8. The method according to claim 4 , wherein the interior of each centrifuge is cleaned twice by purified water after the centrifuge finishes working, a temperature of the purified water for cleaning is controlled to 40° C.-60° C. and cleaning times are 10 seconds to 20 seconds and 5 seconds to 15 seconds respectively.

9. The method according to claim 4 , wherein a rotation speed of a stirring motor of the vacuum crystallization kettle is in a range of 300 r/min to 800 r/min, a vacuum degree of the vacuum crystallization kettle is −0.085 MPa to −0.095 MPa, and the vacuum crystallization kettle cools down the xylitol concentrate to a crystallization start temperature of xylitol of 55° C.-65° C.; a centrifugation time of the centrifuge is 10 minutes to 30 minutes.

10. The method according to claim 4 , wherein the evaporator is a triple-effect evaporator comprising a first-effect evaporator, a second-effect evaporator and a third-effect evaporator, vacuum degrees of the first-effect evaporator, the second-effect evaporator and the third-effect evaporator are 0.02 MPa to 0.1 MPa, −0.05 MPa to −0.07 MPa and −0.085 MPa to −0.095 MPa respectively, and evaporation temperatures of the three evaporators are controlled to 100° C.-120° C., 90° C.-95° C. and 55° C.-65° C. respectively.

Assignees

• Zhejiang Huakang Pharmaceutical Co Ltd
• Univ Zhejiang
• Univ Zhejiang Technology

Inventors

• Yang Jian
• Zheng Yi
• Zhang Taogang
• Gao Han
• Li Mian
• Liu Zhiqiang
• Zheng Yuguo
• Mao Baoxing
• Zhang Xiaojian
• Fan Weiwei

Classifications

• C07C29/78 Primary

  by condensation or crystallisation · CPC title

• A23L27/34

  Sugar alcohols · CPC title

• B01D1/26

  Multiple-effect evaporating · CPC title

• B01D9/0022 Primary

  by reducing pressure · CPC title

• B01D21/262

  by using a centrifuge · CPC title