JP2934408B2 - Detergency evaluation method for cleaning liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for evaluating the residual detergency of a cleaning liquid generated when cleaning various production facilities involving chemical treatments, such as the food industry, the pharmaceutical industry, and the pulp and paper industry. The present invention relates to a method for evaluating the detergency of a cleaning solution for obtaining information for determining a treatment policy such as regenerating and using a later cleaning solution or using a renewed cleaning solution after discarding.

[0002]

2. Description of the Related Art Equipment for producing food, medicine, paper pulp, and the like often processes raw materials in a fluid state to produce products. For example, it is composed of a raw material storage device, a transport device, a heating device, a cooling device, a pressurizing device, a processing device including mixing and separation, a filling device, and a piping device for connecting these devices. Things. When operating such a production facility, the charged raw material undergoes various treatments while moving through the facility. Dirt easily adheres to the inside.

[0003] These stains lead to deterioration of the performance of the apparatus, variation in quality, or contamination of the product. Therefore, it is necessary to clean the inside of the apparatus according to the adhesion of the stains or by periodically cleaning the inside of the apparatus. General. However, if the target device is small, it is easy to disassemble and clean the constituent devices, but if it is a large-scale device, it is not easy to disassemble and clean the devices. Therefore, in order to save time and labor for cleaning, a method of filling and circulating a cleaning liquid containing a surfactant or a solvent in the apparatus in the apparatus and peeling and removing dirt attached to the inside of the apparatus is performed. Have been done.

[0004] According to the stationary cleaning method (hereinafter referred to as CIP, which is an abbreviation of Cleaning in Place), the inside of the device constituting the device is cleaned by circulation of a cleaning liquid without disassembling the device as described above. The dirt that has been dissolved and removed by washing by circulating and using a large amount of cleaning liquid is discharged out of the apparatus together with the cleaning liquid. A part of the cleaning liquid with a low degree of dirt is discarded, but the rest is adjusted by adding fresh water or a cleaning agent together with the rinsing water of the apparatus to adjust the composition until the dirt accumulates and becomes unusable. It was usually used repeatedly.

[0005] By the way, as a cleaning liquid used for cleaning equipment handling organic substances in the food industry or the like, a commercially available aqueous solution of an alkaline cleaning agent containing a surfactant, a solvent, a pH adjuster, and the like is often used. When the dirt inside the treatment apparatus is cleaned using such an alkaline cleaning liquid, the amount of the alkali component effective as a cleaning agent, that is, the P-alkalinity is reduced, while the alkali component derived from the dirt is added and the total alkali component is reduced. The amount, ie, M-alkalinity, increases. Therefore, in general, as an index of the remaining cleaning capacity,
It is recommended to use the ratio of M-alkalinity to P-alkalinity (M / P ratio).

However, the M / P ratio is determined by measuring the M-alkalinity and the P-alkalinity by adding a reagent to a sample of the washing liquid and calculating from these measured values. In addition, there is a problem that it is necessary to increase the number of times of analysis in order to increase the reliability of the measurement result, and there is a limit in further increasing the measurement frequency. In order to check the degree of contamination of the cleaning liquid, it is conceivable to apply a method of measuring the light transmittance of the cleaning liquid or a method of measuring the electric conductivity, but these methods can be automated and relatively. Although simple, it was not always effective in determining the residual cleaning power of the cleaning solution.

[0007]

SUMMARY OF THE INVENTION Accordingly, the present invention makes it possible to effectively use the recovered cleaning liquid used for cleaning food and other equipment for processing and production until the residual cleaning power is lost. In order to solve the above problem, an object of the present invention is to provide a method for quickly measuring the residual cleaning power of a cleaning liquid without human intervention, and further provide a method for measuring the residual cleaning power of such a cleaning liquid with high reliability. It is intended for that purpose.

[0008]

According to the method for evaluating the detergency of a cleaning solution of the present invention, which can achieve the above-mentioned object, a method for evaluating the detergency of a cleaning solution containing an alkaline cleaning agent is used to evaluate the absorbance of the cleaning solution. The conductivity is measured, a deterioration index value obtained by dividing the absorbance by the electric conductivity is obtained, and the deterioration index value is compared with an end-of-life index reference value.

Further, the method for evaluating the detergency of a cleaning solution according to the present invention, which can achieve the above-mentioned object, comprises the steps of evaluating the detergency of a cleaning solution containing an alkaline cleaning agent by measuring the absorbance and electric conductivity of the cleaning solution. It may be characterized by measuring and obtaining a deterioration index value obtained by dividing the absorbance by the electric conductivity, calculating a ratio between the deterioration index value and the end-of-life index reference value, and comparing it with 1. .

Further, the method for evaluating the cleaning power of a cleaning liquid according to the present invention, which can achieve the above object, measures the absorbance and the electric conductivity of the cleaning liquid when evaluating the cleaning power of the cleaning liquid containing an alkaline cleaning agent. Then, a deterioration index value obtained by dividing the absorbance by the electric conductivity is obtained, and M is calculated from the deterioration index value based on a function of the M / P ratio of the cleaning liquid and the deterioration index value obtained in advance for the cleaning liquid. / P
A ratio conversion value is obtained, and the M / P ratio conversion value is calculated as M / P at the end of life.
It may be characterized by comparison with a P ratio reference value.

Further, the method for evaluating the detergency of a cleaning solution according to the present invention, which can achieve the above-mentioned object, provides a method for evaluating the detergency of a cleaning solution containing an alkaline cleaning agent. Is measured, and a deterioration index value obtained by dividing the absorbance by the electric conductivity is obtained. The deterioration index value is determined based on a function of the M / P ratio of the cleaning liquid and the deterioration index value obtained in advance for the cleaning liquid. , An M / P ratio converted value is calculated from the M / P ratio, and the ratio of the M / P ratio converted value to the M / P ratio reference value at the end of life is calculated and compared with 1.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The washing liquid used in the present invention is preferably an alkaline aqueous solution containing a surfactant, a solvent and a pH adjuster, and a commercially available aqueous solution of an alkaline detergent can be used. Such an alkaline cleaning liquid is prepared in a cleaning liquid storage tank in a CIP facility attached to a main facility, and is circulated and used for cleaning dirt inside a food processing facility. The deteriorating cleaning liquid containing is recovered in the cleaning liquid storage tank and temporarily stored. If necessary, the sludge is separated and separated, filtered, and the concentration of the detergent is adjusted to regenerate and reuse.

When the washing operation is repeatedly performed, dirt gradually accumulates in the washing liquid in the washing liquid storage tank. Therefore, conventionally, the analysis operation is manually performed to obtain the M / P
The ratio was measured, and when this value became equal to or longer than the life reference value of the cleaning liquid, for example, 1.1, the cleaning liquid was discarded. On the other hand, in the present invention, absorbance is measured as an index for organic stains contained in the washing solution, that is, BOD, and the absorbance here is characteristic according to the light absorption spectrum of the stain substance in the washing solution. It is preferable to perform measurement using light having an appropriate absorption wavelength. Ultraviolet light can be usually used as the light used for such measurement, but visible light or infrared light may be used.

Further, the electric conductivity is measured as an index for the detergency of the cleaning solution, that is, the hydroxyl group concentration. Since the measured value of the absorbance and the measured value of the electric conductivity obtained in this manner show different values depending on the composition of the cleaning agent contained in the cleaning solution, the type of the stain substance, and the concentration of the cleaning solution itself, etc.
It goes without saying that the dilution degree of the measurement sample, the measurement conditions, and the like must always be kept constant.

By the way, there is no correlation between the measured absorbance value and the measured electric conductivity and the M / P ratio. However, the deterioration index value obtained by dividing the measured absorbance value by the measured electric conductivity value is different from the M / P ratio. It was found for the first time that there was a clear correlation between the M / P ratio. Therefore, the present invention, based on this new knowledge, by combining the absorbance that can be automatically measured even by unmanned, and the electrical conductivity that can be automatically measured even by unmanned, from the absorbance measured value and the electric conductivity measured value Using a deterioration index value that can be automatically calculated, the remaining cleaning power of the cleaning liquid was evaluated as follows.

That is, first, when the M / P ratio of the alkaline cleaning liquid whose cleaning power is to be measured reaches a reference value of the M / P ratio at the end of life, for example, 1.1, a deterioration index value (absorbance measured value) Is divided by the measured value of electrical conductivity). Then, the deterioration index value is set as a reference index value at the end of the life, and is compared with the deterioration index value obtained by measuring the cleaning liquid in the cleaning liquid storage tank to determine whether there is residual cleaning power or whether the life has ended. I do.

Further, the ratio of the above-mentioned deterioration index value to the end-of-life index reference value, that is, the deterioration index value / the end-of-life index reference value, or the end-of-life index reference value / the deterioration index value, is calculated. By comparing 1 with 1, it may be determined whether there is residual detergency or whether the life has expired. In this case, when the deterioration index value / life end index reference value is smaller than 1, it indicates that the detergency still remains, and (1-deterioration index value / life end index reference value).
It will be understood that the value of indicates the percentage of residual cleaning power.

Alternatively, a deterioration index value obtained by dividing a measured absorbance value by a measured electric conductivity value of an alkaline cleaning liquid whose detergency is to be measured in the same manner as described above, and an M / P corresponding to the deterioration index value. By measuring the ratio and
A function of the M / P ratio and the deterioration index value is obtained in advance. Then, the deterioration index value obtained by measuring the cleaning liquid in the cleaning liquid storage tank is substituted into this function to obtain the M / P
By calculating the ratio conversion value and comparing it with a preset M / P ratio reference value at the end of life, for example, 1.1,
A method of determining whether there is residual cleaning power or whether the life has expired may be adopted.

Furthermore, the ratio of the M / P ratio converted value obtained from the deterioration index value of the cleaning liquid as described above to the M / P ratio reference value at the end of the life, that is, the M / P ratio converted value / the end of the life. M / P
By calculating a ratio reference value or an M / P ratio reference value / M / P ratio conversion value at the end of life, and comparing this ratio with 1,
A method of determining whether there is residual cleaning power or whether the life has expired may be adopted.

In the present invention, the conversion of the deterioration index value obtained by dividing the measured absorbance value by the measured electric conductivity value to the M / P ratio value can be performed using a graph or the like, but is automatically performed by a machine. You can also. The comparison between the deterioration index value or the M / P ratio converted value and the end-of-life index reference value or the end-of-life M / P ratio reference value can be performed by reading by an operator. The result can be output as an alarm signal or an operation signal for operating a valve or the like.

Further, the calculation of the ratio between the deterioration index value and the end-of-life index reference value or the calculation of the ratio between the M / P ratio converted value and the end-of-life M / P ratio reference value is automatically performed by a machine. be able to. The comparison between the obtained ratio and 1 can be performed by reading by an operator, or can be automatically performed by a machine. And
When comparing the above ratio and 1, it is possible for an operator to determine the presence or absence of residual cleaning power or to determine the margin of residual cleaning power by determining the difference, but this is automatically performed by a machine. It is also possible to output the result as an alarm signal or as an operation signal for operating a valve or the like.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for evaluating the detergency of a cleaning liquid according to the present invention will be described with reference to an example of cleaning and cleaning the inside of a milk processing facility. milk,
In addition, by circulating a washing liquid consisting of a 2% aqueous solution of sodium hydroxide between the sterilizing equipment for coffee milk and the washing liquid storage tank, dirt inside the sterilizing equipment is washed, and the deteriorated washing liquid containing dirt is stored in the washing liquid. Collected in tank. The ultraviolet light absorbance (dimensionless number) and electric conductivity (μS
/ Cm), M-alkalinity (mg / l) and P-alkalinity (mg / l).

In the above-mentioned measurement of the ultraviolet absorbance, since the absorbance of light becomes too large for a cleaning solution with much dirt and direct measurement cannot be performed, the cleaning solution is washed with fresh water for 10 minutes.
A highly accurate measurement value was obtained by a method of measuring the absorbance of a measurement sample diluted twice. Then, a deterioration index value (MΩcm) was calculated by dividing the value of the ultraviolet absorbance by the value of the electric conductivity measured for the undiluted cleaning liquid.

Next, a scatter diagram was prepared by displaying the above-mentioned deterioration index values with respect to the M / P ratio calculated from the measured values of the above-mentioned M-alkalinity and P-alkalinity (FIG. 1). . In this scatter diagram, the deterioration index value of the cleaning liquid of the milk sterilization equipment and the deterioration index value of the cleaning liquid of the coffee milk sterilization equipment are all the same regression line, that is,

Where x is the M / P ratio, y is the degradation index value, and r = 0.
91. Shows a high correlation with the M / P ratio.

From the regression line in FIG. 1, when the reference value of the M / P ratio at the end of the life of the cleaning liquid is, for example, 1.08, the index of deterioration of the degree of deterioration of the cleaning liquid is about 0.016. End time index reference value: Based on 0.016,
It was found that the remaining cleaning power could be determined.

[0026]

According to the method for evaluating the detergency of a cleaning solution of the present invention, a decrease in detergency due to the use of a cleaning solution containing the same alkaline cleaning agent can be automatically evaluated without human intervention. By measuring the cleaning ability of the cleaning liquid at high frequency or continuously, it is possible to further improve the measurement accuracy, and to economically and efficiently perform the work of cleaning and cleaning various production facilities. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a scatter diagram showing a correlation between an M / P ratio and a deterioration index value according to the present invention for a cleaning liquid for a milk sterilization facility and a cleaning liquid for a coffee milk sterilization facility.

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Tokuyasu Nishiyama 1227-4 Hatsuzawa-cho, Hachioji-shi, Tokyo Takao Park Heights A1424 (58) Field surveyed (Int. Cl. ⁶ , DB name) G01N 33/00

Claims (4)

(57) [Claims] In evaluating the detergency of a cleaning solution containing an alkali cleaning agent, the absorbance and the electric conductivity of the cleaning solution are measured, and a deterioration index value obtained by dividing the absorbance by the electric conductivity is obtained. A method for evaluating the detergency of a cleaning liquid, comprising comparing a deterioration index value with an end-of-life index reference value. 2. In evaluating the detergency of a cleaning solution containing an alkaline cleaning agent, the absorbance and the electric conductivity of the cleaning solution are measured, and a deterioration index value obtained by dividing the absorbance by the electric conductivity is obtained. A method for evaluating the detergency of a cleaning liquid, comprising calculating a ratio between a deterioration index value and an end-of-life index reference value and comparing it with 1. 3. In evaluating the detergency of a cleaning solution containing an alkaline cleaning agent, an absorbance and an electric conductivity of the cleaning solution are measured, and a deterioration index value obtained by dividing the absorbance by the electric conductivity is obtained. An M / P ratio conversion value is calculated from the deterioration index value based on a function of the deterioration index value obtained for the cleaning liquid and the M / P ratio of the cleaning liquid. A method for evaluating the detergency of a cleaning liquid, wherein the method is compared with an M / P ratio reference value. 4. In evaluating the detergency of a cleaning solution containing an alkali cleaning agent, the absorbance and the electric conductivity of the cleaning solution are measured, and a deterioration index value obtained by dividing the absorbance by the electric conductivity is obtained. An M / P ratio conversion value is obtained from the deterioration index value based on a function of the deterioration index value obtained for the cleaning liquid and the M / P ratio of the cleaning liquid. A method for evaluating the detergency of a cleaning liquid, comprising calculating a ratio with an M / P ratio reference value and comparing it with 1.