阅读说明：本技术 一种利用间歇模拟移动床色谱去除木糖水解液中无机酸及乙酸的方法 (Method for removing inorganic acid and acetic acid in xylose hydrolysate by using intermittent simulated moving bed chromatography ) 是由 张军伟 陈建军 袁苗新 于 2020-07-08 设计创作，主要内容包括：本发明公开了一种利用间歇模拟移动床色谱去除木糖水解液中无机酸及乙酸的方法,属于分离提取技术领域。该方法包括以下步骤：(1)木糖水解液预处理；(2)间歇模拟移动床色谱去除木糖水解液中无机酸和乙酸。本发明不仅能高效地从木糖水解液中连续分离出无机酸,避免了催化用酸无法回收、中和除酸产生“三废”等问题,还解决了木糖水解液中主要副产物乙酸对后续发酵的抑制问题,且能同时将无机酸和乙酸分离出,实现综合利用。(The invention discloses a method for removing inorganic acid and acetic acid in xylose hydrolysate by using intermittent simulated moving bed chromatography, belonging to the technical field of separation and extraction. The method comprises the following steps: (1) pretreating xylose hydrolysate; (2) and removing inorganic acid and acetic acid in the xylose hydrolysate by using intermittent simulated moving bed chromatography. The method not only can efficiently and continuously separate the inorganic acid from the xylose hydrolysate, avoid the problems of 'three wastes' and the like caused by the fact that the acid for catalysis cannot be recovered and neutralized for acid removal, but also solves the problem of inhibiting subsequent fermentation by the main byproduct acetic acid in the xylose hydrolysate, and can simultaneously separate the inorganic acid and the acetic acid to realize comprehensive utilization.)

1. A method for removing inorganic acid and acetic acid in xylose hydrolysate by using intermittent simulated moving bed chromatography, which is characterized by comprising the following steps:

(1) pretreatment of xylose hydrolysate: filtering the xylose hydrolysate to remove colloid and solid matters, removing color matters in the xylose hydrolysate by using active carbon or resin, and evaporating and concentrating to obtain a raw material;

(2) and (3) intermittent simulated moving bed chromatographic separation: separating the raw material obtained in the step (1) by intermittent simulated moving bed chromatography to remove inorganic acid and acetic acid; the intermittent simulated moving bed chromatography takes H-type strong acid cation resin as stationary phase resin and deionized water as an eluent, and the working temperature is 40-65 ℃; the intermittent simulated moving bed chromatogram comprises a No. 1 chromatographic column, a No. 2 chromatographic column, a No. 3 chromatographic column, a No. 4 chromatographic column, a No. 5 chromatographic column and a No. 6 chromatographic column which are sequentially connected in series, and comprises a zone I, a zone II, a zone III and a zone IV, wherein the zone I, the zone II and the zone III respectively contain 2 chromatographic columns which are sequentially connected in series, and the zone IV contains 6 chromatographic columns which are sequentially connected in series; the zone I is positioned between an eluent inlet and a raw material inlet; the zone II is positioned between the raw material inlet and the inorganic acid component outlet; the III zone is between the inorganic acid component outlet and the acetic acid component outlet, and the IV zone is between the eluent inlet and the saccharide component outlet.

2. The method as claimed in claim 1, wherein the corn cob, bagasse, straw, eucalyptus wood or birch wood of the agricultural and forestry waste is subjected to crushing, water washing and hot water leaching, and then hydrolyzed by 0.5-2.0% of inorganic acid to obtain xylose hydrolysate; filtering to remove colloid and solid, removing color substances by using activated carbon or resin, and evaporating and concentrating at 55-65 ℃ to obtain a raw material; in the raw materials, the concentration of saccharides is 50-70 mg/mL, the concentration of inorganic acid is 10-20 mg/mL, and the concentration of acetic acid is 5-10 mg/L.

3. The method according to claim 1, wherein the stationary phase resin is any one of Dowex 99 or 50W H type, JK 006H type, XAD 4H type, D001H type or LS001H type, and the particle size of the resin is 120-320 μm; the aspect ratio of the chromatographic stationary phase is as follows: 15: 1-30: 1.

4. The method according to claim 1, wherein the chromatographic column is insulated by circulating water with a concentric jacket at a temperature of 40-65 ℃; the front and the back of each chromatographic column are provided with a distributed electromagnetic valve bank, the eluent inlet, the raw material inlet, the saccharide outlet, the inorganic acid outlet and the acetic acid outlet are respectively provided with an eluent valve, a raw material valve, a saccharide component valve, an inorganic acid component valve and an acetic acid component valve, and the electromagnetic valve banks are controlled to be opened or closed by a PLC program to realize the simulated movement of raw materials or elution water, saccharides or acid components flowing out and a chromatographic stationary phase column; the adjacent chromatographic columns are connected by pipelines, and one-way valves are arranged in the pipelines.

5. The method according to claim 1, wherein step (2) comprises in particular the steps of:

(a) opening an eluent valve before the No. 1 chromatographic column to inject eluent, opening a raw material valve before the No. 3 chromatographic column to inject raw materials, and controlling the ratio of the raw materials to the water to be 1: 1.5-1: 2.5; the inorganic acid component outlet at the end of the No. 4 chromatographic column flows out the inorganic acid with the weak retention component; the acetic acid component outlet at the end of the No. 6 chromatographic column flows out the strong reserved component acetic acid of the last period; the carbohydrate of the intermediate retention component is retained in the chromatographic zone between column No. 3 and column No. 4;

(b) after the step (a) is finished, closing a front raw material valve of a No. 3 chromatographic column and a tail inorganic acid component valve of a No. 4 chromatographic column, forming an independent chromatographic separation area from the No. 1 chromatographic column to the No. 6 chromatographic column, enabling eluent to flow in the direction from the No. 1 chromatographic column to the No. 6 chromatographic column, enabling medium reserved components and strong reserved components to flow into a chromatographic system under the pushing of the eluent, and enabling medium reserved component saccharides to flow into a saccharide component valve at the tail of the No. 6 chromatographic column;

(c) after the step (b) is finished, switching an eluent inlet from the front end of the No. 1 chromatographic column to the front end of the No. 2 chromatographic column; the raw material inlet is switched from the front end of the No. 3 chromatographic column to the front end of the No. 4 chromatographic column; the inorganic acid component outlet is switched from the tail end of the No. 4 chromatographic column to the tail end of the No. 5 chromatographic column; the acetic acid component outlet or the saccharide component outlet is switched from the end of the No. 6 chromatographic column to the end of the No. 1 chromatographic column.

(d) After the step (c) is switched, repeating the step (a) and the step (b) for operation; after running each period, the position of each port is moved forward by one chromatographic column along the flowing direction of the eluent, and the initial position is recovered after 6 cycles are completed.

6. The method according to claim 1, wherein the eluent has a flow rate of 4 to 6mL/min, the raw material has a flow rate of 2 to 3mL/min, the inorganic acid component has a flow rate of 3 to 4mL/min, the acetic acid component has a flow rate of 4 to 5mL/min, the saccharide component has a flow rate of 5 to 6mL/min, the time of step (a) is 4 to 7min, and the time of step (b) is 8 to 12 min.

Technical Field

The invention belongs to the technical field of separation and extraction, and relates to a method for removing inorganic acid and acetic acid in xylose hydrolysate by using intermittent simulated moving bed chromatography.

Background

The saccharides refer to polyhydroxy aldehydes or ketones, are the most abundant biomolecules in nature and are widely distributed. The functional sugar with special effects has the special effects of low calorie, providing nutrition, promoting improvement of human physiological functions and the like, is initially applied to the nutritional health care and food industry, and then gradually develops into the non-food fields of chemical industry, pharmacy and the like, so that the application of the functional sugar in the commercial market is increasingly concerned.

Xylose is one of the major products in functional sugars. In industry, the primary sugar liquid is obtained by catalytic hydrolysis of agricultural and sideline products such as corncobs, straws, bagasse and the like through dilute inorganic acid, and then the xylose is prepared through refining, concentration and crystallization. In this respect, it is first necessary to remove the acid used for the catalytic hydrolysis and to reduce the amount of organic acid by-products produced during the hydrolysis, supplying the downstream sections with a pure xylose solution. The acid for catalytic hydrolysis comprises sulfuric acid, hydrochloric acid and the like, the byproduct organic acid comprises formic acid, acetic acid, levulinic acid and the like, and the acetic acid has relatively high content in the hydrolysate.

Disclosure of Invention

In order to solve the problems, the invention provides a method for removing inorganic acid and acetic acid in xylose hydrolysate by using intermittent simulated moving bed chromatography, which can continuously separate and remove the inorganic acid and the acetic acid in the xylose hydrolysate.

The technical scheme of the invention is as follows:

a method for removing inorganic acid and acetic acid in xylose hydrolysate by using intermittent simulated moving bed chromatography comprises the following steps:

(1) pretreatment of xylose hydrolysate: filtering the xylose hydrolysate to remove colloid and solid matters, removing color matters in the xylose hydrolysate by using active carbon or resin, and evaporating and concentrating to obtain a raw material;

(2) and (3) intermittent simulated moving bed chromatographic separation: separating the raw material obtained in the step (1) by intermittent simulated moving bed chromatography to remove inorganic acid and acetic acid; the intermittent simulated moving bed chromatography takes H-type strong acid cation resin as stationary phase resin and deionized water as an eluent, and the working temperature is 40-65 ℃; the intermittent simulated moving bed chromatogram comprises a No. 1 chromatographic column, a No. 2 chromatographic column, a No. 3 chromatographic column, a No. 4 chromatographic column, a No. 5 chromatographic column and a No. 6 chromatographic column which are sequentially connected in series, and comprises a zone I, a zone II, a zone III and a zone IV, wherein the zone I, the zone II and the zone III respectively contain 2 chromatographic columns which are sequentially connected in series, and the zone IV contains 6 chromatographic columns which are sequentially connected in series; the zone I is positioned between an eluent inlet and a raw material inlet; the zone II is positioned between the raw material inlet and the inorganic acid component outlet; the III zone is between the inorganic acid component outlet and the acetic acid component outlet, and the IV zone is between the eluent inlet and the saccharide component outlet.

Furthermore, corncob, bagasse, straw, eucalyptus or birch of the agricultural and forestry waste are subjected to crushing, water washing and hot water leaching treatment, and then hydrolyzed by 0.5-2.0% of inorganic acid to obtain xylose hydrolysate; filtering to remove colloid and solid, removing color and luster substances by using activated carbon or resin, and evaporating and concentrating at 55-65 ℃ to obtain a raw material; in the raw materials, the concentration of saccharides is 50-70 mg/mL, the concentration of inorganic acid is 10-20 mg/mL, and the concentration of acetic acid is 5-10 mg/L.

Further, the stationary phase resin is any one of Dowex 99 or 50W H type, JK 006H type, XAD 4H type, D001H type or LS001H type, and the particle size of the resin is 120-320 mu m; the aspect ratio of the chromatographic stationary phase is as follows: 15: 1-30: 1.

Further, the chromatographic column is insulated by circulating water through a concentric jacket, and the temperature is 40-65 ℃; the front and the back of each chromatographic column are provided with a distributed electromagnetic valve bank, the eluent inlet, the raw material inlet, the saccharide outlet, the inorganic acid outlet and the acetic acid outlet are respectively provided with an eluent valve, a raw material valve, a saccharide component valve, an inorganic acid component valve and an acetic acid component valve, and the electromagnetic valve banks are controlled to be opened or closed by a PLC program to realize the simulated movement of raw materials or elution water, saccharides or acid components flowing out and a chromatographic stationary phase column; the adjacent chromatographic columns are connected by pipelines, and one-way valves are arranged in the pipelines.

Further, the step (2) specifically comprises the following steps:

(a) opening an eluent valve before the No. 1 chromatographic column to inject eluent, opening a raw material valve before the No. 3 chromatographic column to inject raw materials, and controlling the ratio of the raw materials to the water to be 1: 1.5-1: 2.5; the inorganic acid component outlet at the end of the No. 4 chromatographic column flows out the inorganic acid with the weak retention component; the acetic acid component outlet at the end of the No. 6 chromatographic column flows out the strong reserved component acetic acid of the last period; the carbohydrate of the intermediate retention component is retained in the chromatographic zone between column No. 3 and column No. 4;

(b) after the step (a) is finished, closing a front raw material valve of a No. 3 chromatographic column and a tail inorganic acid component valve of a No. 4 chromatographic column, forming an independent chromatographic separation area from the No. 1 chromatographic column to the No. 6 chromatographic column, enabling eluent to flow in the direction from the No. 1 chromatographic column to the No. 6 chromatographic column, enabling medium reserved components and strong reserved components to flow into a chromatographic system under the pushing of the eluent, and enabling medium reserved component saccharides to flow into a saccharide component valve at the tail of the No. 6 chromatographic column;

(c) after the step (b) is finished, switching an eluent inlet from the front end of the No. 1 chromatographic column to the front end of the No. 2 chromatographic column; the raw material inlet is switched from the front end of the No. 3 chromatographic column to the front end of the No. 4 chromatographic column; the inorganic acid component outlet is switched from the tail end of the No. 4 chromatographic column to the tail end of the No. 5 chromatographic column; the acetic acid component outlet or the saccharide component outlet is switched from the end of the No. 6 chromatographic column to the end of the No. 1 chromatographic column.

(d) After the step (c) is switched, repeating the step (a) and the step (b) for operation; after running each period, the position of each port is moved forward by one chromatographic column along the flowing direction of the eluent, and the initial position is recovered after 6 cycles are completed.

Further, the flow rate of the eluent is 4-6 mL/min, the flow rate of the raw material is 2-3 mL/min, the flow rate of the inorganic acid component is 3-4 mL/min, the flow rate of the acetic acid component is 4-5 mL/min, the flow rate of the saccharide component is 5-6 mL/min, the time of the step (a) is 4-7 min, and the time of the step (b) is 8-12 min.

The working mechanism of the invention is as follows: the H-type strong acid cation resin chromatographic stationary phase has high charge density, and according to the Tao-nan repulsion principle, strong electrolyte components are repelled when passing through the stationary phase and cannot enter resin micropores without retention; the non-dissociative component is not repelled and permeates into the micropores of the resin to be reserved; thereby causing a partitioning phenomenon between the components in the spaces between the resin particles and the components in the resin pores. The extent to which the dissociated electrolyte components are repelled is related to the strength of the acid and the electrolyte dissociation. The saccharide is neutral molecule, the sulfuric acid or hydrochloric acid is strong electrolyte, the acetic acid is weak electrolyte, and the three are respectively retained, non-retained and strongly retained (partial hydrogen bond action) on the H-type strong acid cation resin chromatographic stationary phase. When the three components of the saccharide, the sulfuric acid or the hydrochloric acid and the acetic acid in the xylose hydrolysate pass through the stationary phase, the sulfuric acid or the hydrochloric acid firstly flows out, the saccharide then flows out, and the acetic acid finally flows out. Six columns form an intermittent port reset simulated moving bed four-zone open-loop chromatographic system, and can realize continuous flow of xylose hydrolysate, a raffinate port in the first substep collects weak retention component sulfuric acid or hydrochloric acid, an extraction port collects strong retention component acetic acid in the last period, and an extraction port in the second substep collects medium retention component saccharides. And then switching ports along the flowing direction of the eluent to simulate the stationary phase movement of the chromatographic column, and continuously and simultaneously removing the inorganic acid and the acetic acid in the xylose hydrolysate by using the intermittent simulated moving bed chromatography.

The invention has the beneficial effects that:

(1) the method can continuously separate and remove the inorganic acid and the acetic acid in the xylose hydrolysate, and has higher acid yield, sugar yield, acid purity and sugar solution purity;

(2) the invention can prevent the concentration of the extraction solution from being diluted, the recovered inorganic acid can be used for hydrolysis again after the concentration is adjusted, the concentration of the component outlet is higher than that of a four-zone or five-zone or a sequential simulated moving bed, and the subsequent concentration cost is reduced;

(3) the invention reduces the resin dosage and the number of chromatographic columns, and reduces the equipment investment and the production loss; the back mixing of the feed liquid is reduced, and the purity and the yield of the product are improved;

(4) the purity of the three components of the sugar, the inorganic acid and the acetic acid which are continuously recovered by the method reaches more than 90 percent.

Drawings

FIG. 1 is a schematic diagram of a four-zone simulated moving bed chromatography.

FIG. 2 is a schematic diagram of sequential simulated moving bed chromatography.

FIG. 3 is a schematic diagram of a five-zone simulated moving bed chromatography.

FIG. 4 is a schematic diagram of four-zone batch simulated moving bed chromatography; fig. 4a and 4b show port configurations in a first time interval and a second time interval, respectively.

FIG. 5 is a schematic diagram of a four-zone port rearrangement batch simulated moving bed chromatography.

Detailed Description

The batch simulated moving bed chromatography described in the following examples is shown in fig. 5, and comprises a No. 1 chromatographic column, a No. 2 chromatographic column, a No. 3 chromatographic column, a No. 4 chromatographic column, a No. 5 chromatographic column and a No. 6 chromatographic column which are sequentially connected in series, and comprises a zone I, a zone II, a zone III and a zone IV, wherein the zone I, the zone II and the zone III respectively contain 2 chromatographic columns which are sequentially connected in series, and the zone IV contains 6 chromatographic columns which are sequentially connected in series; the zone I is positioned between an eluent inlet and a raw material inlet; the zone II is positioned between the raw material inlet and the inorganic acid component outlet; the III zone is between the inorganic acid component outlet and the acetic acid component outlet, and the IV zone is between the eluent inlet and the saccharide component outlet. The chromatographic column is insulated by circulating water through a concentric jacket, and the temperature is 40-65 ℃; the front and the back of each chromatographic column are provided with a distributed electromagnetic valve bank, the eluent inlet, the raw material inlet, the saccharide outlet, the inorganic acid outlet and the acetic acid outlet are respectively provided with an eluent valve, a raw material valve, a saccharide component valve, an inorganic acid component valve and an acetic acid component valve, and the electromagnetic valve banks are controlled to be opened or closed by a PLC program to realize the simulated movement of raw materials or elution water, saccharides or acid components flowing out and a chromatographic stationary phase column; the adjacent chromatographic columns are connected by pipelines, and one-way valves are arranged in the pipelines.

The method for removing inorganic acid and acetic acid in xylose hydrolysate by using intermittent simulated moving bed chromatography in the following embodiment comprises the following steps:

(a) opening an eluent valve before the No. 1 chromatographic column to inject eluent, opening a raw material valve before the No. 3 chromatographic column to inject raw materials, and controlling the ratio of the raw materials to the water to be 1: 1.5-1: 2.5; the inorganic acid component outlet at the end of the No. 4 chromatographic column flows out the inorganic acid with the weak retention component; the acetic acid component outlet at the end of the No. 6 chromatographic column flows out the strong reserved component acetic acid of the last period; the carbohydrate of the intermediate retention component is retained in the chromatographic zone between column No. 3 and column No. 4;

(b) after the step (a) is finished, closing a front raw material valve of a No. 3 chromatographic column and a tail inorganic acid component valve of a No. 4 chromatographic column, forming an independent chromatographic separation area from the No. 1 chromatographic column to the No. 6 chromatographic column, enabling eluent to flow in the direction from the No. 1 chromatographic column to the No. 6 chromatographic column, enabling medium reserved components and strong reserved components to flow into a chromatographic system under the pushing of the eluent, and enabling medium reserved component saccharides to flow into a saccharide component valve at the tail of the No. 6 chromatographic column;

(c) after the step (b) is finished, switching an eluent inlet from the front end of the No. 1 chromatographic column to the front end of the No. 2 chromatographic column; the raw material inlet is switched from the front end of the No. 3 chromatographic column to the front end of the No. 4 chromatographic column; the inorganic acid component outlet is switched from the tail end of the No. 4 chromatographic column to the tail end of the No. 5 chromatographic column; the acetic acid component outlet or the saccharide component outlet is switched from the end of the No. 6 chromatographic column to the end of the No. 1 chromatographic column.

(d) After the step (c) is switched, repeating the step (a) and the step (b) for operation; after running in each period, the position of each port is moved backwards by one chromatographic column along the flowing direction of the eluent, and the initial position is recovered after 6 cycles are completed.

The "about" ranges mentioned in the examples below are given as concentration values. + -. 1 mg/mL.