KR19980067316A - Recovery method of organic acid - Google Patents

Abstract

The present invention relates to a method for recovering organic acids using nanofiltration and water-splitting electrodialysis.

An object of the present invention is to utilize the high divalent cation removal capacity of nanofiltration, a one-stage light bulb using a conventional two-step electrodialysis process using desalination electrodialysis and ion exchange resin as a purification process By simplifying the dialysis process, the present invention provides a new organic acid recovery process that can improve the efficiency of the process, reduce the production cost, reduce the amount of utility used, and efficiently use the site.

Accordingly, the present invention provides a method for recovering an organic acid fermentation broth using electrodialysis, comprising: i) a nanofiltration step of removing impurities and hardness substances from the fermentation broth using a nanofiltration device; ii) a method of recovering an organic acid consisting of an electrodialysis process in which the purified fermentation broth obtained in the above process is put into an electrodialysis apparatus and recovered.

Description

Recovery method of organic acid

The present invention relates to a method for recovering organic acids using nanofiltration and water-splitting electrodiaysis.

Organic acids such as lactic acid, acetic acid and succinic acid are additives used in the food processing, chemical and medical industries and are produced by synthesis and fermentation processes. Fermentation is produced in the form of organic acid salts through fermentation of cheap carbohydrates. The fermentation process is carried out at neutral pH and is produced in the form of a salt, and also contains by-products to be removed such as microorganisms and proteins. Therefore, in the production of organic acid using the fermentation process, the production cost for refining this increases. Therefore, in order to produce organic acid through fermentation, a purification process for purifying the organic acid salt produced in the fermentation process and an organic acid production process for converting the form of the organic acid salt into an organic acid as a final product are required.

Conventional organic acid production process, as disclosed in European Patent Publication No. 0393818, used a two-stage electrodialysis process using desalination electrodialysis and ion exchange resin as a purification process, which will be described in more detail. As shown in Fig. 1, the fermentation broth 7 containing the lactate produced in the fermentation process 1 and impurities such as microorganisms and proteins is sent into the desalting electrodialysis process 2 for the recovery and concentration of the lactate in solution. In the desalting electrodialysis process (2), microorganisms and other by-products are removed from the process via a diluent stream (9), some of which are recycled to the fermentation process (1), and the concentrate stream with concentrated lactate (8) prevents production of lactic acid. To a water-splitting electrodialyzer (4). Before entering the Water-Splitting Electrodialysis Process (hereinafter referred to as WSED process) (4), hardness materials (Ca ²⁺ , Mg ^2+, etc.) that can cause membrane fouling and scale formation in the process are introduced. To remove the lactate is converted to sodium lactate (Na-Lactate) via Na ⁺ type ion exchange resin (3). The sodium lactate solution (9) introduced during the WSED process exits the base stream (11) containing NaOH and the acid stream (10) containing the final product lactic acid. The base stream containing NaOH is also recycled for pH adjustment in the fermentation process.

However, the above process has a problem such as the inefficiency of the process, the increase in production cost, the increase in utility amount due to the complicated two-step WSED process.

While the present inventors are doing research to improve the shortcomings of the conventional production process, by simplifying the conventional complex two-step WSED process to the one-step WSED process, the efficiency of the process, the production cost can be reduced and the utility usage can be reduced. The present invention was completed.

Accordingly, an object of the present invention is to use the high divalent cation removal capacity of nanofiltration, using a conventional two-step electrodialysis process using desalination electrodialysis and ion exchange resin as a purification process using nanofiltration as a purification process. By simplifying the step electrodialysis process, it provides a new organic acid recovery process that can improve the efficiency of the process, the reduction of production cost, the reduction of utility usage and the efficient use of the site.

That is, the present invention provides a method for recovering an organic acid fermentation broth using electrodialysis, comprising: i) a nanofiltration step of removing impurities and fine substances from the fermentation broth using a nanofiltration device; ii) a method of recovering organic acids formed by an electrodialysis process in which the purified fermentation broth obtained in the above process is put into an electrodialysis apparatus and recovered.

Figure 1 shows a schematic diagram of a conventional organic acid purification and production process using desalination electrodialysis and ion exchange resin.

Figure 2 shows a schematic diagram of the organic acid purification and production process using nanofiltration according to the present invention.

Figure 3 shows a detailed view of the nanofiltration device used in the present invention.

Figure 4 shows a detailed view of the water-splitting electrodialyzer used in the present invention.

Hereinafter, the present invention will be described in detail with the accompanying drawings.

2 shows a simplified process according to the invention. The fermentation broth 7 produced in the fermentation process 1 is sent to the nanofiltration device 12 to remove impurities and hardness substances such as microorganisms and proteins. In the nanofiltration process 12, the filtrate stream 13 from which impurities and hardness are removed is directly introduced into the WSED process 4 without undergoing another purification process, and is concentrated in the concentrate stream 14 containing microorganisms and other by-products. Some will be recycled to the fermentation process (1) and others will be taken out of the process.

Figure 3 is a detailed view of the nanofiltration device used in the present invention. The nanofiltration device 12 used in the present invention is composed of an equalization tank 15, a high pressure pump 17, a filtration membrane vessel 18 and a cooling device 16. NF45-2540 (spiral wound, effective area 20 ft ² , MWCO 180 ~ 400) was used as the nanofiltration membrane 19. The fermentation broth 7 introduced into the nanofiltration device 12 is transported into the filtration membrane 19 through the high pressure pump 17. In the filtration membrane 19, the microorganisms contained in the fermentation broth 7 and the hard substance such as Ca ²⁺ and Mg ²⁺ that cause membrane fouling and scale formation in the WSED process 4 cannot pass through the filtration membrane 19 and are concentrated. Circulated back to the equalizer 15 along stream 14 or disposed of out of process, sodium lactate passes through filtration membrane 19 and enters WSED process 4 through filtrate flow 13. In this process, a cooling device 16 is installed in the equalization tank 15 in order to cool the heat deforming the filtration membrane 19. In order to increase the recovery rate of sodium lactate and the concentration of the microorganisms, the equalization tank 15 as shown in FIG. ) To install the batch process.

4 is a detailed view of the water-splitting electrodialyzer used in the present invention. The purified sodium lactate solution 13 is fed to the WSED process 4 to produce lactic acid. In the WSED process (4), water molecules electrolyzed by the bipolar membrane 21 generate H ⁺ ions and OH ^- ions, and the generated OH ^- ions combine with Na ⁺ ions to form a NaOH solution (11). The base stream 11 is recycled for pH adjustment of the fermentation process 1. In addition, the generated H ⁺ ions are combined with the lactic acid ions to form the final product lactic acid (10).

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the present invention is not limited to the following examples.

Example 1

After the fermentation broth produced through the lactic acid fermentation process was purified using the nanofiltration apparatus of FIG. 2, the removal rate of Mg ²⁺ , Ca ²⁺ ions, acetic acid and glucose, and the recovery rate of lactic acid were measured. As a result, the removal rates of Mg ²⁺ , Ca ²⁺ ion, acetic acid and glucose were 81.0, 70.8, 36.8 and 60.9%, respectively, and the recovery rate of lactic acid was 80.0%. The measurement results are shown in Table 1.

TABLE 1

Result of measurement of recovery rate of lactic acid by nanofiltration process

Example 2

In order to investigate the effect of hardness on nanofiltration process, 33.6 ppm of Mg ²⁺ and 11 ppm of Ca ²⁺ ions were added to the fermentation broth produced through the lactic acid fermentation process of Example 1 After artificial addition, Mg ²⁺ , Ca ²⁺ ions, acetic acid and glucose removal rate, and lactic acid recovery rate were measured in the same manner as in Example 1.

As a result, the removal rates of Mg ²⁺ , Ca ²⁺ ions, acetic acid and glucose were 74.6, 66.9, 34.6 and 56.5%, respectively, and the recovery rate of lactic acid was 83.3%.

The measurement results are shown in Table 2.

TABLE 2

Effect of Hard Materials on Nanofiltration Process

Example 3

In order to investigate the effect of glucose on the nanofiltration process, glucose was artificially added to the fermentation broth produced through the lactic acid fermentation process, and then the same procedure as in Example 1 was carried out for Mg ²⁺ , Ca ²⁺ ions, acetic acid, glucose The removal rate and recovery rate of lactic acid were measured. As a result, the removal rates of Mg ²⁺ , Ca ²⁺ ion, acetic acid and glucose were 82.2, 72.8, 27.1 and 32.4%, respectively, and the recovery rate of lactic acid was 79.2%. The measurement results are shown in Table 3.

TABLE 3

Effect of Glucose on Nanofiltration Process

Example 4

In order to determine the feasibility and economics of the lactic acid recovery process using the nanofiltration process according to the present invention, the sodium lactate solution purified in Example 1 was added to the WSED process to measure the recovery rate, current efficiency and energy consumption of lactic acid.

The water-splitting electrodialyzer used in the WSED process uses a bipolar membrane stack consisting of four parts for the production of lactic acid and NaOH. The ion exchange membrane is a bipolar membrane (Neosepta BP-1). ) And cation exchange membrane (Neosepta CM-1 ) Are used together. The measurement results are shown in Table 4 below.

TABLE 4

Current efficiency and energy consumption measurement results

According to the organic acid recovery process of the present invention, the efficiency of the process by reducing the conventional two-stage electrodialysis process using desalination electrodialysis and ion exchange resin as a one-stage electrodialysis process using nanofiltration as a purification process, The production cost can be reduced and the utility can be used efficiently.

Claims (4)

A method for recovering an organic acid fermentation broth using electrodialysis, the method comprising: i) a nanofiltration process for removing impurities and hardness of fermentation broth using a nanofiltration device; ii) A method for recovering an organic acid formed by an electrodialysis process in which a fermentation broth obtained in an electrical process is put into an electrodialysis apparatus and recovered. The method of claim 1, wherein the nanofiltration device comprises an equalization tank, a high pressure pump, a cooling device, a filtration membrane container, and a nanofiltration membrane. The method for recovering organic acids according to claim 1, wherein the electrodialysis apparatus is composed of a bipolar membrane and a cation exchange membrane. The method of claim 1, wherein the concentrated solution containing the microorganisms and by-products obtained in the nanofiltration process is recycled to the fermentation process.