JP2001133450A - Normal hexane extraction substance autoanalyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately hand an elusion-shaped normal hexane being generated in an extraction process, further break the emulsion, and then perform the dehydration, evaporation, and recovery of the normal hexane within an autoanalyzer for economical, compact design when inventing the normal hexane extraction substance autoanalyzer for automatic analysis by adopting a normal hexane extraction method in the analysis of oil content in sample water such as factory drain. SOLUTION: Normal hexane after extraction is sucked and is introduced by a capillary in the succeeding analysis process, a chemical is added in the state of the capillary, and further heating is made to break an emulsion state where oil content has been dissolved to the normal hexane heterogeneously. Further, a nozzle with funnels for easily sucking emulsion phase has been used. Also, the dehydration of the normal hexane has been made for two steps, and recovery after the evaporation is also made for two steps to solve problems.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method of extracting and analyzing oil contained in water such as industrial wastewater or river water using a solvent such as normal hexane or carbon tetrachloride, and more particularly, to an analysis method using normal hexane extraction. The present invention relates to an automatic analyzer for performing continuous or automatic analysis.

[0002]

2. Description of the Related Art Among the methods for extracting oil contained in sample water to be analyzed with a solvent, a method for measuring a normal hexane extractable substance using normal hexane is JIS K0.
It is a general method for analyzing oil content in factory wastewater, which is specified in 102. However, there is no automatic analyzer that automates from extraction of the oil to separation of the normal hexane phase.

[0003] As another conventional method of analyzing oil content in factory effluent, there is a carbon tetrachloride extraction method as an extraction method. This method is also specified in JIS K0102, and a method of analyzing by this analysis method can be selected. This carbon tetrachloride extraction method has been conventionally used in automated analyzers. However, this solvent, carbon tetrachloride, became a solvent that was not generally available as a carcinogenic substance, and this method had to be changed to another method.

A conventional automatic analyzer using the carbon tetrachloride extraction method cannot be used at all if this solvent is replaced with normal hexane. The reason is that the carbon tetrachloride extraction method is a solvent extraction method in which an oil component is extracted with a solvent and analyzed, but in the subsequent process, an infrared absorption spectroscopy is used in this case. When the solvent is normal hexane, the infrared absorption spectroscopy cannot be measured because normal hexane itself has a property of absorbing infrared rays. In addition, although all solvents are hardly soluble in water, there is a difference in specific gravity between carbon tetrachloride and normal hexane.
63 g / cm ^3, which is heavier than water, whereas normal hexane is 0.66 g / cm ^3, which is lighter than water, so that the handling of the solvent is completely different. That is, it must be considered that a completely different analyzer will be obtained if the solvent is replaced with normal hexane.

[0005]

First, a general analysis method is described. Normal hexane is added to a sample water to be analyzed.
The oil in the sample water is dissolved into the normal hexane side by stirring the mixture (this operation is called oil extraction with normal hexane). When left standing after stirring, it separates into a water and normal hexane layer. The normal hexane phase is taken out and heated to evaporate normal hexane. The remaining residue is oil, and this mass is measured to determine the oil concentration. In order to automate this method, it is necessary to consider that when the sample water and normal hexane are mixed and stirred and allowed to stand, they are normally separated into two layers when they are left standing. In some cases, two or three layers are included. This heterogeneous phase usually shows a so-called emulsion state in a state where it is turbid in an emulsion state under the influence of a surfactant or the like. That is, the problem to be solved by the present invention starts with accurately separating and extracting the normal hexane layer containing the emulsion phase. Further, this emulsion phase cannot be sent to the next analysis step as it is, and the emulsion must be broken and dehydrated to obtain a homogeneously dissolved normal hexane phase. This step is the most complicated step by repeating heating and addition of a drug called a salting-out agent in manual analysis. One of the problems is to automatically perform this emulsion breaking method in the analyzer.

After evaporating normal hexane,
As a disaster prevention and environmental measure, the process of recovering normal hexane must be built into the equipment and then compactly designed.

[0007] Since the normal hexane after oil extraction in the sample water is sucked by a thin tube and sent to the next step using a thin tube, it is necessary to automatically take measures to prevent the thin tube from clogging.

[0008] As a method for destroying the emulsion phase of normal hexane, heating alone is not sufficient, and the addition of a salting-out agent (in this case, using an aqueous solution of sodium chloride) is required. is necessary.

It is necessary to devise a method for automatically separating water from normal hexane after passing through the thermal decomposition section, further provide a dehydration column for complete dehydration, and take measures to prevent foreign substances from being mixed into the thin tube.

It is necessary to design a method for cooling normal hexane vapor generated from the normal hexane evaporating section and recovering the vapor efficiently and economically.

[0011]

SUMMARY OF THE INVENTION In the present invention, the normal hexane phase is collected when the sample water and normal hexane are stirred and allowed to stand, the layers are separated, and then the normal hexane in which the oil is dissolved is collected and sent to the next analysis step. Various methods can be considered, but the most compact and economical method is to send the normal hexane layer from the upper part in consideration of facilitating thermal decomposition treatment etc. in the middle of the process to the next analysis step. I thought it was advantageous to be able to design. However, as described above, if it is normally extracted into normal hexane, it can be easily sucked and collected, but if it becomes an emulsion state, it is very difficult to suck. Therefore, the present invention further collects the emulsified layer while rotating the sample in a funnel attached to the tip of the suction nozzle near the center of the sample bottle, detects the level in the height direction with a liquid level meter, and adjusts to a certain suction condition. Can be collected.

When the normal hexane phase becomes an emulsion state, the emulsion state is destroyed before sending to the analysis step. In this method, normal hexane in an emulsion state is introduced into a thin tube, and the thin tube is destroyed by using a method in which the thin tube is heated from the outside of the tube and a salting-out agent is added depending on circumstances. In addition, in order to perform this process efficiently, the stirring effect in a thin tube and the heating effect can be improved by winding a thin tube in a coil shape in a thermal decomposition apparatus.

As a measure to prevent clogging of the tube when suction is introduced from the normal hexane extraction unit by a thin tube, a filter is provided, and a washing operation is automatically repeated by backflowing pure water for each sample analysis.

The method of adding the salting-out agent for breaking the emulsion is to add the salting-out agent to normal hexane flowing into the introduction capillary immediately before introduction into the thermal decomposition section. This has contributed to the economy of adding much less than the addition to the entire sample water and thereby to the compact design of the apparatus.

In the method of separating water from normal hexane after thermal decomposition, a liquid level gauge is provided in a separation tank, a difference in conductivity between the two layers is detected, water is discharged from the lower part, and normal hexane is sucked from the upper part. After suction, it is sent to a dehydration column by a thin tube.
The dehydration column was packed with anhydrous sodium sulfate, and was equipped with filters before and after the dehydration column to make it detachable so that column exchange was convenient and foreign matter was prevented from being mixed.

Since the normal hexane evaporation chamber is made of aluminum and is easy to process, a heater can be embedded in the outer frame wall and the degree of sealing can be increased. The recovery of the normal hexane vapor discharged from the evaporation chamber was improved by installing an air-cooled recovery unit and an electronically cooled recovery unit in two stages, enabling a compact design.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments shown in the drawings. FIG. 1 is a conceptual diagram of an automatic analyzer according to the present invention.

Referring to FIG. 1, the structure of the apparatus will be described. The sample water is put in the extraction tank (8) in advance, and normal hexane is added to the extraction tank (8) by pumping normal hexane from the extraction normal hexane tank (2). This extraction tank is provided with a turntable for continuously processing a plurality of different samples, and the sample water to be processed can be switched by a turntable motor (9). By rotating a stirrer (10) at the bottom of the extraction tank, mixing and stirring of sample water and normal hexane in the tank is performed. In this step, the oil in the sample water is extracted into normal hexane, and the normal hexane is lowered by the suction nozzle (13) by the suction device operating mechanism (11), and is suctioned by the pump (15). Thereafter, the salting-out agent is sent through a thin tube, and if necessary, is suctioned from the suction port (18) of the tank (17) and added to the extracted normal hexane sent from the other side through the three-way joint (20) of the thin tube. Then, it is sent to the thermal decomposition device (21). Separation tank for removing water from normal hexane after thermal decomposition (22)
The normal hexane phase is further separated by suction, dehydrated through a dehydration column (27), and the dehydrated normal hexane is discharged to a cup (28) for evaporative measurement. When the cup for evaporating and measuring the water content of the sample of the number to be analyzed is filled, it is sent to the evaporation chamber (30). The residual substance in the cup after evaporation in the evaporation chamber is subjected to mass measurement, which is the final analysis step, for each cup. Further, the normal hexane evaporated in the evaporation chamber is recovered via the cooler (31) and is reused. For mass measurement, information is automatically sent from the balance built into the device to the data processing unit, and data management is performed individually. In this embodiment, the mass measurement is manually performed without automation due to the problem of economy. The information processing section is also provided with a control section of the apparatus.

FIG. 2 shows the extraction part of the extract with respect to the method of collecting normal hexane in the extraction tank (8). Normal hexane layer (3
4) Consists of an emulsion layer of normal hexane (35) and a sample aqueous layer (36). The boundary surface with the sample water layer is detected by the liquid level gauge (12), and at that time the funnel (3
7) The suction nozzle (13) is lowered, and the upper edge of the funnel (37) is set almost at the boundary between the emulsion layer (35) and the sample aqueous layer (36) to start suction. The funnel in this case is one in which the tip of the funnel bottom is closed in a conical shape.The relationship between the suction nozzle diameter and the center depth of the funnel and the center of the funnel depends on the nature of the emulsion generated in the sample water normally handled. Design in advance to match.
In this manner, the emulsion phase can be easily collected by suction.

Next, FIG. 3 shows the details of the thermal decomposition unit.
The normal hexane phase from which the oil was extracted is introduced through a thin tube, and the salting-out agent is sucked by a pump (19) on the way, added from the three-way joint (20) of the thin tube, and introduced into the thermal decomposition unit. The internal structure of the thermal decomposition device (21) is such that a capillary portion (38) in which a capillary for extracting and introducing normal hexane is wound in a coil shape is held in the thermal decomposition device (21). A heater (39) is embedded in the housing to adjust the room temperature. In this case, in this embodiment, the thin tube is a Teflon tube having an inner diameter of 2φ, and the processing amount is 20 to 50 ml / min.
The salting-out agent is sodium chloride (

## STR1 ## 20% solution of NaCl) is added at 20% to the normal hexane amount. After that, heat decomposition machine (21)
In the course of passing through the coiled thin tube (38) inside, it is heated to a heating temperature of 50 to 60 ° C. while being stirred in the thin tube and decomposed.

FIG. 4 shows a separation tank. The separation tank (22) has the same shape as the separating funnel for analysis, and a magnetic stirrer (40) is provided at the lower part of the tank to perform the operation of gently rocking. The nozzle (24) for sucking normal hexane is a thin tube made of metal, which also serves as a liquid level gauge. The liquid level meter employs a conductivity formula, and the sample water layer (44) shows a conductivity because it contains a salt, whereas the normal hexane layer (43) has a property of no conductivity. In other words, the usage is that the tip of the liquid level sensor is the sample water layer (44) below the normal hexane (indicating conductivity).
The normal hexane layer is the point at which the sensor stops showing conductivity due to the water phase being drawn out from the lower part of the separation tank (22) through the water pipe (41) by the solenoid valve (42) by the solenoid valve (42) and the liquid level being lowered. To be recognized. After water was removed by this operation, normal hexane was sucked into the suction nozzle (2).
Suction is performed from the suction hole (45) beside the tip of 4) and sent to the next step.

Normal hexane after water separation requires further dehydration. In this case, a dehydration column in which anhydrous sodium sulfate was sealed in a glass tube was used. This column is designed to be easily replaceable, and filter paper made of polyflon fiber is installed at the entrance and exit at the front and back of the column. Crystals of anhydrous sodium sulfate and other powdery foreign substances are evaporatively measured in normal hexane in the next step. The danger of spilling into the cup is prevented.

FIG. 5 shows a normal hexane evaporation recovery section. A heater (46) is built in the evaporation chamber (30), and an evaporation measuring cup (28) already containing normal hexane.
(10 cups in this embodiment) are put into the evaporation chamber together with the cassette and heated to 80 ° C. The evaporated normal hexane is sucked by a pump (33), passed through an air-cooled recovery unit (31), and liquefied here is recovered in a recovery tank (32). The liquid cooled and liquefied in 47) is similarly recovered in the recovery tank (48), and the recovery is completed. In this embodiment, the loading and unloading of the cassette is performed manually, but can be automated as long as the device is profitable.

The mass of the cup after the evaporation process is measured by a built-in balance, and based on the mass of each cup measured and stored in advance, the data is processed and automatically obtained as an analysis value from the information processing unit. The output data is output.

The analysis accuracy of the automatic analyzer obtained in this embodiment will be described below. Table 1 shows that the soluble oil used in the rolling of the cold-rolled steel sheet was subjected to manual analysis by using the oil in the form of an emulsion which was actually used.
It shows the result of adjusting to mg / l and repeatedly analyzing with the automatic analyzer. As for the state of the analysis process, the emulsion state was completely destroyed, and no problem occurred in the analysis operation. Further, the analysis accuracy indicates that the repetition accuracy is good as shown in Table 1. Next, Table 2 shows the theoretical values and the results of comparative analysis performed by an automatic analyzer using water mixed with salad oil. As shown in Table 2, the analysis results obtained by the automatic analyzer of the present invention were satisfactory as compared with the theoretical values. Next, Table 3 shows the results of a trial of normal manual analysis of a sample of factory wastewater and wastewater before treatment in the factory and a comparison test with the automatic analyzer of the present invention. Table 3 shows that the correspondence between the hand analysis and the analysis result by the automatic analyzer according to the present invention is very good, and that there is a high correlation.

As described in detail above, according to the automatic analyzer according to the present invention, the sample water within the range of the ordinary manual analysis performed according to JIS K0102 in which the analysis method such as various factory drainage and river water is defined. It was shown that automatic analysis was possible, and that the automatic analyzer was also applicable as a monitor for monitoring factory wastewater.
Considering the introduction of the automatic analyzer according to the present invention into an analysis center, a great effect can be expected as a labor-saving facility.

[Brief description of the drawings]

FIG. 1 shows a conceptual diagram of an automatic analyzer according to an embodiment of the present invention.

FIG. 2 is a schematic diagram illustrating a method of collecting a normal hexane phase and an emulsion phase from the upper layer after stirring the extraction tank (8) in FIG.

FIG. 3 is a schematic diagram for explaining a pyrolysis unit in FIG. 1 and steps before and after it.

FIG. 4 is a schematic diagram for explaining an operation method of the dehydration tank (22) in FIG.

FIG. 5 is a schematic diagram for explaining a normal hexane evaporation chamber and a recovery section in FIG. 1;

[Explanation of symbols]

1 liquid level gauge 4 suction pump 2 normal hexane tank 5 suction pump 3 normal hexane suction nozzle 6 pressure reducing valve 7 pure water outlet 36 sample water layer 8 extraction tank 37 funnel 9 turntable motor 38 coiled thin tube 10 stirrer 39 heater 11 suction Nozzle operation mechanism 40 Stirrer 12 Liquid level gauge 41 Drain pipe 13 Suction nozzle 42 Solenoid valve for drainage 14 Solenoid valve for cleaning 43 Normal hexane layer 15 Suction pump 44 Sample water layer 16 Liquid level gauge 45 Details of suction hole 17 Salting agent tank 46 Heater 18 Suction nozzle 47 Electronic cooler 19 Suction pump 48 Normal hexane recovery container 20 Capillary tube 3-way connection part 21 Heat decomposer 22 Separation tank 23 Suction nozzle operating mechanism 24 Suction nozzle / level gauge 25 Cleaning solenoid valve 26 Suction pump 27 Dehydration column 28 Cup for evaporative measurement 29 Cup for evaporative measurement Cassette 30 evaporation chamber 31 cooler 32 normal hexane collecting container 33 the suction pump 34 normal hexane layer 35 emulsion layer

Claims (8)

[Claims] 1. An extraction unit for extracting oil from water of an analysis sample by using a normal hexane extraction method in a step of analyzing an oil in an analysis sample, and a heterogeneous phase which is non-uniformly dissolved in milk or the like in normal hexane after extraction. An automatic analyzer for normal hexane extractable substances, comprising a heat decomposition unit for homogenization and a normal hexane dehydration separation unit for removing water mixed in normal hexane after heat decomposition. 2. A method of separating a normal hexane layer separated into layers in an extraction section according to claim 1, wherein a suction nozzle serving also as a liquid level gauge for detecting a liquid level and a funnel having a function of storing at a tip thereof are provided. Normal hexane extractable substance automatic analyzer characterized by the following: 3. A method for introducing and treating normal hexane after extraction in the thermal decomposition unit according to claim 1, wherein the structure is such that the normal hexane is passed through a thin tube, and the thin tube is wound in a loop or coil shape and heated from outside the thin tube. Hexane extractable substance automatic analyzer characterized by adopting the method 4. A normal hexane extraction substance automatic analyzer, further comprising a normal hexane evaporation recovery section, an extraction substance measurement section, and a data processing section in addition to the configuration of claim 1. 5. The method according to claim 1, wherein after extracting with normal hexane, the normal hexane is suctioned and collected, and a salting-out agent is added in the middle of a thin tube to be introduced into the thermal decomposition section. Normal hexane extractable substance analyzer characterized by having a three-way connection part 6. A dewatering / separation unit according to claim 1, wherein water is drained from a lower portion of the separation tank, a boundary between a water layer and a normal hexane layer is detected by a liquid level meter, and water is automatically drained. An automatic analyzer for normal hexane extract, characterized in that only the hexane phase is collected in a thin tube and then dehydrated in a dehydration column packed with anhydrous sodium sulfate in the next dehydration step. 7. A normal hexane extractable substance analyzing apparatus according to claim 2, wherein a filter capable of backwashing is provided in a thin tube between a suction nozzle tip and a suction pump. 8. A normal hexane extractable substance automatic analyzer according to claim 4, wherein the normal hexane evaporating and recovering unit has a structure in which an air cooling recovery method and an electronic cooling recovery method are used in combination.