JPH0822307B2 - Method for cleaning and sterilizing equipment used for desalting sugar-tight liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a method for cleaning and sterilizing equipment used for desalting molasses liquid, and particularly for cleaning a molasses liquid desalting device using a diaphragm such as an ion exchange membrane. , Sterilization method.

[Prior Art] Conventionally, molasses filtration and desalination devices have been contaminated or clogged due to water-insoluble adhesive substances produced by the growth action of microorganisms, resulting in poor liquid flow. Method of sterilizing by using a system sterilizer, heating, etc., or disassembling the electrodialysis tank and manually washing a large number of ion exchange membranes and chamber frames one by one with a sponge-like instrument, and then reassembling Is being done.

[Problems to be Solved by the Invention] However, sufficient heat sterilization is required from the viewpoint of heat resistance, etc., for a desalting device using a filter or a diaphragm such as an ion exchange resin or an ion exchange membrane. It is impossible to do. Although it is possible to use an organic fungicide, it is often prohibited to use molasses as food (eg, formalin). Further, even if it happens to be permitted to be used, it has a drawback that it cannot be used because it causes irreversible adsorption to an ion exchange resin or an ion exchange membrane. Further, manually dismantling and cleaning the electrodialysis tank requires damage to the ion exchange membrane, requires a large amount of time and labor, and stops the main process, resulting in sugar loss.

[Means for Solving Problems] The present inventors have aimed to eliminate the drawbacks of these conventional methods and to find a washing and sterilizing means that works suitably for a molasses desalting apparatus using a diaphragm. As a result of various studies and studies, it was found that the above-mentioned object can be achieved by selecting an inorganic drug that can be used in foods and using it under specific conditions. Thus, the present invention is a method for cleaning and sterilizing a device used for desalting molasses liquid, characterized in that the device used for desalting molasses liquid is contacted with hydrochloric acid at a temperature of 40 ° C or higher.

The hydrochloric acid used in the present invention is particularly preferably used for food additives, and the concentration of hydrochloric acid is suitably about 15 to 30%. If the temperature is lower than the above range, the bactericidal power is weak. On the contrary, if the temperature is higher than the above range, hydrochloric acid is significantly evaporated, which is dangerous in operation, and further effects cannot be expected. Not preferable.

In addition, the operating temperature must be 40 ° C or higher.
At temperatures below this, there is virtually no germicidal activity. Considering the sterilization effect and work safety, the upper limit of temperature is about 80 ° C. 55 ~ within these temperature ranges
When 65 ° C is adopted, it has a substantially complete bactericidal action, and can also clean the fungi attached to the device,
Further, it is particularly preferable because it has high safety in work. The equipment used for desalting molasses to which the method of the present invention is applied includes a molasses filter, a desalting apparatus main body, a processing apparatus before and after the desalting apparatus, and auxiliary equipment. As a concrete cleaning and sterilizing means, a method of immersing these devices in hydrochloric acid to be used, a means of applying vibration or the like to the hydrochloric acid or the device to sufficiently bring the hydrochloric acid into contact with the device, or hydrochloric acid Appropriate means can be adopted such as flowing the above through these devices.

[Action] The action in the present invention is not always clear as the action of hydrochloric acid on the hydrolysis of the water-insoluble adhesive substance produced by the microorganisms.
Hydrochloric acid of ~ 30%, 40 ~ 80 ° C easily destroys the cells of microorganisms due to the hydrolysis action that acts on the cells as an acid against the microorganisms and the permeation action due to its high concentration, enabling sterilization and washing at the same time. It seems to be.

The present inventors collect viable bacteria in the electrodialysis device of the sugar cane raw sugar factory, the pressure detection part of the pressure gauge, and the bacterial flora generation site such as the attached pipe, and produce a large amount of the water-insoluble adhesive substance.
The 10 strains were purely isolated, and the basic properties of these fungi and the water-insoluble adhesive substances produced by the fungi were clarified. As a result, it was revealed that all of these bacteria were Bacillus bacilli, and the water-insoluble adhesive substance was easily dissolved in warm hydrochloric acid, preferably at a temperature of 40 to 60 ° C and a concentration of 15 to 30% hydrochloric acid. I found that.

Next, the result of the test concerning the solubility of the water-insoluble sticky substance will be shown.

[Sample material] No.2 honey from Okinawa's three-stage decoction type sugar cane raw sugar factory was diluted to a solid concentration of 18%, and the isolated strain that produces a water-insoluble sticky substance was used for 72 hours at 55 ° C. After culturing with shaking at, the produced water-insoluble sticky substance was centrifuged and tested.

[Test method] A small piece of a bacterial mass (pellicle) on the culture surface containing a water-insoluble adhesive substance is put into a hydrochloric acid, sulfuric acid or sodium hydroxide solution having a predetermined concentration in a test tube, and the mixture is shaken at a predetermined temperature for about 1 minute to be soluble. Was observed.

[result] The test results are indicated by-, +, ±, ++, and their meanings are as follows.

-Does not dissolve.

± Slightly soluble.

+ Dissolved but incomplete.

++ Completely dissolve.

As a result of testing acetic acid and citric acid in addition to hydrochloric acid, sulfuric acid and sodium hydroxide, they were not dissolved at all.

In this test, the heat-resistant temperature of the ion-exchange membrane, especially the anion-exchange membrane, is 60 ℃, and the practical maximum concentration of hydrochloric acid is 30%.
Therefore, this temperature and concentration are the upper limits. Test results,
It was clarified that when the temperature of hydrochloric acid used for cleaning was 40 ° C or less and the concentration was 15% or less, the effect was drastically reduced. In addition, it was revealed by chemical analysis of the water-insoluble adhesive substance that polymers such as glucose and galactose are the main components.

The present invention can also be used for desalting, filtration, sterilization and cleaning of devices such as whey and soy sauce.

[Example 1] A cation exchange membrane (CMV manufactured by Asahi Glass Co., Ltd.) 900 equipped with a filter
And anion-exchange membrane (AMV manufactured by Asahi Glass Co., Ltd.) 900 sheets were used for desalination of molasses continuously for 24 hours using a desalting device consisting of electrodialysis tanks alternately arranged with a membrane interval of 0.75 mm.
The pressure at the inlet of the filter increased from 0.2 kg / cm ² to 0.7 kg / cm ² , and the pressure at the inlet of the dialysis tank increased from 0.4 kg / cm ² to 1.5 kg / cm ² . After desalting molasses was stopped, 18% hydrochloric acid for food addition kept at 40 ° C was passed through the filter and dialysis tank at a rate of 20 m ³ / hour for 30 minutes instead of molasses, and then normal After returning to operation, the pressure was 0.3 kg / cm ² in the filter and 0.7 kg in the dialysis tank.
It fell to / cm ² . When this device was disassembled and examined, adhesion of fungi was found in some places, and this fungus was likely to grow in an appropriate environment. Therefore, the temperature of hydrochloric acid
Raised to 55 ° C., it was subjected to the same operation, to 0.2 kg / cm ² at the inlet pressure filter, the dialysis cell respectively reduced to 0.4 kg / cm ^2, a result of dismantling the remaining fungi observed It was After that, the filter and the dialysis tank are sterilized and washed by repeating the washing at 40 ° C. and 55 ° C. every two days to ensure stable operation.

[Example 2] An electrodialyzer (a DU-ob type manufactured by Asahi Glass Co., Ltd.) having a membrane effective area of 0.23 m ^{2 in which} a cation membrane and an antifouling anion membrane are combined is operated in a batch system for 7 cycles / day for 3 hours / cycle. For 30 days.

After diluting the No. 2 molasses from the three-stage decoction type sugar cane sugar factory in Okinawa with water about twice, the molasses filtered with a filter precoated with diatomaceous earth was used as the raw material, molasses concentration 35%, temperature 40 ° C, membrane Electrodialysis was performed at a surface flow rate of LV = 10 cm / sec and a transmembrane voltage of 0.2 to 0.4 V / pair. After 3 days from the start of electrodialysis, the flow rate of the stock solution into the electrodialysis tank decreased, and on the 4th day, with the electrodialysis tank installed, after washing with pump circulation with water, 50 ° C, 15% hydrochloric acid was used. The pump was circulated and washed again with water.

By this washing operation, the membrane surface flow velocity of the stock solution was completely recovered. In this way, by washing the inside of the electrodialysis tank with warm hydrochloric acid once every 2 to 3 days, the electrodialysis tank is disassembled after the operation is continued for 30 days without disassembling the electrodialysis tank. As a result, the adhesion of the water-insoluble adhesive substance was not observed at all.

Claims (3)

[Claims] 1. A method for cleaning and sterilizing a device used for desalting molasses liquid, which comprises bringing the device used for desalting molasses liquid into contact with hydrochloric acid at a temperature of 40 ° C. or higher. 2. The cleaning and sterilizing method according to claim 1, wherein the temperature is 40 to 80 ° C. 3. The concentration of hydrochloric acid is 15 to 30%.
How to clean and sterilize.