Desalting and purifying process and system for tartaric acid

Abstract

The invention provides a tartaric acid desalting and purifying process and system, and relates to the technical field of separation and purification. The tartaric acid desalting and purifying process comprises the following steps: washing and replacing an anion exchange column by using a dilute tartaric acid solution, washing residual tartaric acid in the anion exchange column by using pure water as an eluent to obtain the dilute tartaric acid solution, and repeating the operation. The tartaric acid desalting and purifying system comprises a washing column inlet area, a high-sodium discharging area, a washing low-sodium inlet area and a low-sodium cleaning area. The dilute tartaric acid solution generated in the tartaric acid separation and purification process is used for cleaning and replacing the sodium ions in the anion exchange column, so that the water consumption can be greatly reduced, and the content of the sodium ions in the tartaric acid product can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of separation and purification, and relates to a tartaric acid desalting and purification process and system. Background Art

[0002] In the continuous bed process of tartaric acid desalination, due to the long service life of the anion exchange column and the weak alkalinity of the anion exchange column itself, the anion exchange column may not be cleaned after washing. Specifically, after washing the anion exchange column with a large amount of water, for example, the water consumption for washing a single column reaches 4m 3 , the anion exchange column is still in an alkaline state. When it comes into contact with weak or strong acid, a large amount of sodium ions are released from the anion exchange column, and the maximum sodium ion can reach 3000-10000ppm. When the anion exchange column is connected to the product tank in the next cycle, a large amount of released sodium ions will directly enter the product tank, resulting in an increase in the sodium ion concentration in the obtained tartaric acid product. The sodium ion content in tartaric acid can reach 300ppm, and the purity of the tartaric acid product can generally only reach about 98%, which seriously affects the purity and quality of the tartaric acid product. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a tartaric acid desalting and purification process and system.

[0004] The technical solution of the present invention is as follows:

[0005] A tartaric acid desalting and purification process, comprising:

[0006] The dilute tartaric acid solution is used to clean and replace the anion exchange column, and then pure water is used as an eluent to clean the tartaric acid remaining in the anion exchange column to obtain the dilute tartaric acid solution, and the above operation is repeated.

[0007] Preferably, the tartaric acid raw material liquid passes through a plurality of first separation units connected in series in a forward direction in sequence to collect tartaric acid;

[0008] The plurality of first separation units are respectively filled with the anion exchange columns.

[0009] More preferably, the plurality of first separation units are 2 first separation units.

[0010] Further preferably, the dilute tartaric acid solution is used to clean and replace the anion exchange column comprising the second first separation unit.

[0011] Preferably, the step of washing the residual tartaric acid in the anion exchange column with pure water as an eluent comprises a plurality of second separation units connected in series in a forward direction;

[0012] The plurality of second separation units are respectively filled with anion exchange columns.

[0013] A tartaric acid desalting and purification system comprises a water wash column inlet zone, a high sodium effluent zone, a water wash low sodium zone and a low sodium cleaning zone;

[0014] The tartaric acid raw material liquid passes through the water washing column area and replaces and collects the tartaric acid;

[0015] The high sodium efflux zone is a dilute tartaric acid solution that cleans the anion exchange column and replaces the unremoved sodium ions;

[0016] The water washing into the low sodium zone uses pure water as an eluent to wash the residual tartaric acid in the anion exchange column of the water washing into the column zone and obtain the dilute tartaric acid solution;

[0017] The feed liquid of the low sodium cleaning zone is the dilute tartaric acid solution washed into the low sodium zone, and the discharge liquid of the low sodium cleaning zone is applied to the high sodium discharge zone.

[0018] Preferably, the water wash column zone comprises a plurality of first separation units connected in series in a forward direction;

[0019] The plurality of first separation units are respectively filled with anion exchange columns.

[0020] Preferably, the operating time of the tartaric acid desalination purification system is: the operating time of the water wash into the column zone is 0-250s, the operating time of the high sodium efflux zone is 0-720s, the operating time of the water wash into the low sodium zone is 250-1300s, and the operating time of the low sodium cleaning zone is 1500-2500s.

[0021] Preferably, the feed rates of the water washing into the column zone, the high sodium discharge zone, the water washing into the low sodium zone and the low sodium cleaning zone are 2-3.5 m / s respectively. 3 / h.

[0022] Preferably, the water wash into the column zone, the high sodium discharge zone, the water wash into the low sodium zone and the low sodium cleaning zone independently adopt a forward feeding method.

[0023] The beneficial effects of the present invention are:

[0024] (1) The present invention uses the dilute tartaric acid solution obtained by washing as the eluent for the anion exchange column, which has the following effects compared with the existing process: 1) The amount of water required for washing the anion exchange column is greatly reduced from 4m3 / cm2 to 1m3 / cm2 of the original single column washing. 3 Reduce to 1.5m around or higher 3; 2) Greatly reduced the sodium ion impurities in the product, and the sodium ion impurity content in the tartaric acid product dropped from the original 300ppm to below 50ppm; 3) Greatly improved the purity of the tartaric acid product, and the purity of the tartaric acid product was increased from about 98% in the original process to 99.5% or above.

[0025] (2) The present invention uses the dilute tartaric acid solution obtained by water washing as the eluent of the anion exchange column, does not introduce other impurities, and the dilute tartaric acid solution can be repeatedly obtained and recycled. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The invention relates to a tartaric acid desalting and purification system according to the prior art.

[0027] Figure 2 This is the tartaric acid desalination and purification system of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0029] On the one hand, the present invention provides a tartaric acid desalting and purification process, comprising:

[0030] The dilute tartaric acid solution is used to clean and replace the residual sodium ions in the anion exchange column, and then the tartaric acid used in the anion exchange column is cleaned with pure water as an eluent to obtain a dilute tartaric acid solution, and the above operation is repeated.

[0031] Aiming at the problem that it is difficult to wash the sodium ions cleanly by water after the anion exchange column is regenerated in the tartaric acid desalination process, resulting in a high sodium ion content in the tartaric acid product, the present invention adopts a dilute tartaric acid solution to wash the anion exchange resin, and utilizes the acidic system of the dilute tartaric acid to replace the residual sodium ions in the anion resin, which can greatly reduce the water consumption of the anion exchange column for washing (reduced by 60% or more), reduce the sodium ion impurities carried by the tartaric acid product (reduced by 80% or more), and improve the purity of the tartaric acid product. The product purity is increased from about 98% in the prior art to 99.5% or more in the present invention. Moreover, in the present invention, the dilute tartaric acid solution can be reused, and no other impurities are introduced.

[0032] In a preferred embodiment of the present invention, the tartaric acid raw material liquid sequentially passes through a plurality of first separation units connected in series in a forward direction to collect tartaric acid;

[0033] The plurality of first separation units are respectively filled with anion exchange columns.

[0034] In the present invention, the tartaric acid raw material liquid (the tartaric acid content is about 80-85wt%) passes through a plurality of first separation units connected in forward series, and a tartaric acid product with high purity (purity of 99.5% or more) can be collected. The first separation unit is cleaned and replaced with a dilute tartaric acid solution to remove the unremoved sodium ions, so that the influence of the unremoved sodium ions in the anion exchange column on the purity of the tartaric acid product in continuous production can be avoided. In the present invention, the anion exchange column can be a weakly alkaline anion exchange column.

[0035] In the present invention, the plurality of first separation units may be 1, 2 or 3 first separation units, etc. In a more preferred embodiment of the present invention, the plurality of first separation units are 2 first separation units.

[0036] Further preferably, the dilute tartaric acid solution is used to clean and replace the second first separation unit in the anion exchange column. When there are two first separation units, the dilute tartaric acid solution is used to clean and replace the second separation unit in the anion exchange column. For example, there can be two first separation units, the first first separation unit is marked as 1#, and the second first separation unit is marked as 2#, then the dilute tartaric acid solution can be used to clean and replace 2#.

[0037] In a preferred embodiment of the present invention, pure water is then used as an eluent to wash the residual tartaric acid in the anion exchange column comprising a plurality of second separation units connected in series in a forward direction;

[0038] The plurality of second separation units are respectively filled with anion exchange columns, preferably, weakly basic anion exchange columns.

[0039] In the present invention, the second separation unit may be 1 second separation unit, 2 second separation units, 3 second separation units, etc., preferably, it may be 2 second separation units.

[0040] Using pure water as an eluent to clean the residual tartaric acid in the anion exchange column can achieve a good removal effect, and obtain a dilute tartaric acid solution, which is used again to clean and replace the residual sodium ions in the anion exchange column, such as the anion exchange column in the second second separation unit mentioned above.

[0041] On the other hand, the present invention also provides a tartaric acid desalination and purification system, which improves the tartaric acid desalination and purification system in the prior art. Figure 1It is a tartaric acid desalination and purification system of the prior art, which is a continuous anion and cation exchange system. The upper 1#-29# resin columns are equipped with cation exchange resins, and the lower 2#-30# resin columns are equipped with anion exchange resins. The system includes an exchange zone (desalting zone, 3-18#), a post-exchange water washing zone (1-2# / 19-20#), a regeneration zone (27-29#, 28-30#), a post-regeneration water washing zone (21-25#, 22-26#) and a water reuse zone (19-20#).

[0042] The tartaric acid desalination and purification system of the present invention is based on the tartaric acid desalination and purification system of the prior art, and is further improved: it comprises a water washing column zone, a high sodium discharge zone, a water washing low sodium zone and a low sodium cleaning zone, as shown in the attached Figure 2 As shown;

[0043] The tartaric acid raw material liquid is washed into the column area and the tartaric acid is replaced and collected;

[0044] The high sodium efflux zone is a dilute tartaric acid solution that cleans the anion exchange column and replaces the unremoved sodium ions;

[0045] The water washing into the low sodium zone uses pure water as an eluent to wash the residual tartaric acid in the anion exchange column of the water washing into the column zone and obtain a dilute tartaric acid solution;

[0046] The feed liquid of the low sodium cleaning zone is a dilute tartaric acid solution which is washed into the low sodium zone, and the discharge liquid of the low sodium cleaning zone is used for the high sodium discharge zone.

[0047] The tartaric acid desalination and purification system of the present invention can not only effectively remove the sodium ions which are difficult to be removed by water washing during the continuous separation and purification of tartaric acid, thereby improving the purity of the obtained tartaric acid product and reducing the sodium ion content in the tartaric acid product, but also can greatly reduce the water consumption.

[0048] In a preferred embodiment of the present invention, the water wash column zone comprises a plurality of first separation units connected in series in a forward direction;

[0049] The first separation units are respectively filled with anion exchange columns, preferably weakly basic anion exchange resins.

[0050] In the present invention, the tartaric acid raw material liquid to be separated and purified (the tartaric acid content is about 80-85%) passes through a plurality of first separation units connected in series in a forward direction, and a tartaric acid product with high purity (purity of 99.5% or more) can be collected. The first separation unit is cleaned and the unremoved sodium ions are replaced by a dilute tartaric acid solution, so that the influence of the unremoved sodium ions in the anion exchange column on the purity of the tartaric acid product in the production of continuous separation and purification can be avoided.

[0051] In the present invention, the plurality of first separation units may be 1 first separation unit, 2 first separation units, 3 first separation units, etc., preferably 2 first separation units, such as first separation unit 1# (corresponding to the 1# exchange resin of the above-mentioned existing system, and so on), first separation unit 2#.

[0052] The high sodium discharge area can include one separation unit, such as separation unit 20#, which adopts the forward feeding method. The dilute tartaric acid solution in the high sodium tank contacts with the anion exchange column of separation unit 20#, thereby replacing the sodium ions that are difficult to remove by water washing. The discharge liquid can be directly discharged to the wastewater station.

[0053] The water washing into the low sodium zone may include the above-mentioned first separation unit 1# and the first separation unit 2#, and adopt a forward series feeding method, using pure water as an eluent to wash the residual dilute tartaric acid in the anion exchange column into the low sodium tank.

[0054] The low sodium cleaning area may include separation unit 19# and separation unit 20#, and adopt a forward series feeding method. The feed liquid is the dilute tartaric acid solution obtained after the above-mentioned pure water is used as the eluent to clean the anion exchange column. The discharge liquid enters the high sodium tank and is used in the high sodium discharge area.

[0055] In a preferred embodiment of the present invention, the operating time of the tartaric acid desalination purification system is: the operating time of the water wash into the column zone is 0-250s, the operating time of the high sodium efflux zone is 0-720s, the operating time of the water wash into the low sodium zone is 250-1300s, and the operating time of the low sodium cleaning zone is 1500-2500s.

[0056] In a preferred embodiment of the present invention, the feed rates of the water washing into the column zone, the high sodium discharge zone, the water washing into the low sodium zone and the low sodium cleaning zone are 2-3.5 m / s respectively. 3 / h. For example, the feed rate of the water washing column zone can be 2-3m 3 / h, the feed rate of the high sodium discharge zone can be 2.5-3.5m 3 / h, the feed rate of water washing into the low sodium zone can be 2-3m 3 / h, the feed rate of the low sodium cleaning zone can be 2.5-3.5m 3 / h.

[0057] In a preferred embodiment of the present invention, the water wash into the column zone, the high sodium discharge zone, the water wash into the low sodium zone and the low sodium cleaning zone independently adopt a forward feeding method.

[0058] The technical solution of the present invention is further described and illustrated according to various embodiments below.

[0059] Example

[0060] In the continuous bed tartaric acid desalination and purification process, the tartaric acid desalination and purification system used in this embodiment is as shown in the attached Figure 2 As shown, it includes a water wash into the column area, a high sodium discharge area, a water wash into the low sodium area and a low sodium cleaning area.

[0061] Water washing column inlet zone: It includes two separation units 1# and 2# (each separation unit contains a weakly alkaline anion exchange column). It adopts a forward series feeding method. The tartaric acid raw material liquid (i.e., water washing material, the tartaric acid content is 83wt%) passes through the above two separation units in sequence, and the output liquid enters the dilution tank; the function of the water washing column inlet zone is to collect most of the tartaric acid in the raw material liquid into the dilution tank through water washing, and finally into the product tank.

[0062] High sodium discharge area: It includes a 20# separation unit, which adopts a forward feeding method and uses the dilute tartaric acid solution in the high sodium tank to contact the anion separation column of the 20# separation unit, thereby replacing the sodium ions that are difficult to remove by water washing, and the discharge liquid is directly discharged to the wastewater station;

[0063] Washing into low sodium zone: including the above-mentioned 1# and 2# separation units, using forward series feeding mode, using pure water as eluent to wash the residual dilute tartaric acid in the anion exchange column into the low sodium tank;

[0064] Low sodium cleaning area: It includes two separation units, 19# and 20#, and adopts a forward series feeding method. The feed liquid is the dilute tartaric acid solution after the anion exchange column is washed with the above-mentioned pure water. The discharge liquid enters the high sodium tank and is used again to clean and replace the sodium ions that are difficult to remove by water washing in the anion separation column of the above-mentioned 20# separation unit.

[0065] The operating time and operating mode are shown in Table 1 below.

[0066] Table 1

[0067]

[0068]

[0069] The results of the sodium ion content in the 20# anion separation column are shown in Table 2 below.

[0070] Table 2

[0071] Serial number Running time / s 20# Sodium ion content / ppm 1 100 3900 2 300 2300 3 500 1600 4 700 4500 5 800 9200 6 900 7600 7 1000 4600 8 1100 4200 9 1200 2000 10 1300 800 11 1400 300 12 1500 100 13 1600 45

[0072] Therefore, compared with the existing tartaric acid desalination process, the process of this embodiment does not need to use a large amount of water to wash the separation column to remove sodium ions, and the water consumption can be reduced by 62.5% (the water consumption is reduced from a single column of 4m 3 Reduced to single column 1.5m 3), the sodium ions in the tartaric acid product can be reduced by about 80% (from about 300 ppm to 45 ppm), and the purity of the tartaric acid product can be increased from about 98% in the existing process to 99.5%, an increase of 1.5%.

[0073] As described above, the basic principles, main features and advantages of the present invention are shown and described. Those skilled in the art should understand that the present invention is not limited by the above embodiments, which are only preferred embodiments of the present invention and cannot be used to limit the scope of the present invention. That is, equivalent changes and modifications made according to the scope of the present invention and the content of the specification should still be within the scope of the present invention. The scope of protection required by the present invention is defined by the attached claims and their equivalents.

Claims

1. A tartaric acid desalting and purification process, characterized in that: include: The dilute tartaric acid solution is used to clean and replace the anion exchange column, and then pure water is used as an eluent to clean the tartaric acid remaining in the anion exchange column to obtain the dilute tartaric acid solution, and the above operation is repeated.

2. The tartaric acid desalting and purification process according to claim 1, characterized in that: The tartaric acid raw material liquid sequentially passes through a plurality of first separation units connected in series in a forward direction to collect tartaric acid; The plurality of first separation units are respectively filled with the anion exchange columns.

3. The tartaric acid desalting and purification process according to claim 2, characterized in that: The plurality of first separation units are 2 first separation units.

4. The tartaric acid desalting and purification process according to claim 3, characterized in that: The dilute tartaric acid solution is used for cleaning and replacing the anion exchange column comprising the second first separation unit.

5. The tartaric acid desalting and purification process according to claim 2, characterized in that: The method of washing the residual tartaric acid in the anion exchange column with pure water as an eluent comprises a plurality of second separation units connected in series in a forward direction; The plurality of second separation units are respectively filled with anion exchange columns.

6. A tartaric acid desalination and purification system, characterized in that: It includes a water wash column inlet area, a high sodium discharge area, a water wash low sodium area and a low sodium cleaning area; The tartaric acid raw material liquid passes through the water washing column area and replaces and collects the tartaric acid; The high sodium efflux zone is a dilute tartaric acid solution that cleans the anion exchange column and replaces the unremoved sodium ions; The water washing into the low sodium zone uses pure water as an eluent to wash the residual tartaric acid in the anion exchange column of the water washing into the column zone and obtain the dilute tartaric acid solution; The feed liquid of the low sodium cleaning zone is the dilute tartaric acid solution washed into the low sodium zone, and the discharge liquid of the low sodium cleaning zone is applied to the high sodium discharge zone.

7. The tartaric acid desalination and purification system according to claim 6, characterized in that: The water wash column inlet zone comprises a plurality of first separation units connected in series in a forward direction; The plurality of first separation units are respectively filled with anion exchange columns.

8. The tartaric acid desalination and purification system according to claim 6, characterized in that: The operation time of the tartaric acid desalination purification system is as follows: the operation time of the water wash into the column zone is 0-250s, the operation time of the high sodium discharge zone is 0-720s, the operation time of the water wash into the low sodium zone is 250-1300s, and the operation time of the low sodium cleaning zone is 1500-2500s.

9. The tartaric acid desalination and purification system according to claim 6, characterized in that: The feed rates of the water washing column zone, the high sodium discharge zone, the water washing low sodium zone and the low sodium cleaning zone are 2-3.5 m / s respectively. 3 / h.

10. The tartaric acid desalting and purification process according to claim 6, characterized in that: The water washing column zone, the high sodium discharge zone, the water washing low sodium zone and the low sodium cleaning zone independently adopt a forward feeding method.

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