JP2022057001A - Pretreatment method for measuring concentration of mercury contained in hydrocarbon mixture, and method of measuring concentration of mercury contained in hydrocarbon mixture - Google Patents

Abstract

To provide a pretreatment method for measuring concentration of mercury contained in a hydrocarbon mixture, which allows for making appropriate and simple measurement of mercury concentration in a hydrocarbon mixture even after the hydrocarbon mixture with a wide boiling point range is fractionated.SOLUTION: A pretreatment method for measuring concentration of mercury contained in a hydrocarbon mixture is provided, the method comprising fractionating the hydrocarbon mixture under normal pressure to separate the mixture into multiple fractions, and cooling the obtained fractions to 0°C or below.SELECTED DRAWING: None

Description

The present invention relates to a pretreatment method for measuring the concentration of mercury contained in a hydrocarbon mixture and a method for measuring the concentration of mercury contained in a hydrocarbon mixture.

Conventionally, as a device for measuring the concentration of mercury in a sample, a mercury concentration measuring device using an atomic absorption spectrometry method has been used (see, for example, Patent Document 1 and Patent Document 2).
The mercury concentration measuring device irradiates the sample gas introduced into the measuring cell (in the case where the sample is a liquid or solid, the gas obtained by vaporizing this sample) with light to detect the absorption amount of light of a specific wavelength, and detects the sample gas. The concentration of mercury contained in the sample is calculated.

Further, as an apparatus for measuring the concentration of mercury in a sample, there is also known an apparatus for analyzing plasma light generated by converting a sample into plasma with a spectroscope and analyzing mercury as a trace component (for example, Patent Document 3 and Patent Document 3). See Patent Document 4).

Further, as a device for measuring the concentration of mercury in a sample, a mercury concentration measuring device using an atomic fluorescence analysis method has been proposed. In such a mercury concentration measuring device, a sample gas introduced into a measurement cell has been proposed. The concentration of mercury contained in the sample gas is calculated by irradiating (when the sample is a liquid or solid, the gas vaporized from this sample) with light of a specific wavelength and measuring the emission intensity.

Such a mercury concentration measuring device includes a mercury collecting tube filled with a mercury collecting agent for collecting mercury in a sample gas, and a heating vaporization means for heating the mercury collecting tube to vaporize mercury. A mercury measuring device for quantifying mercury heated and vaporized by the heated vaporizing means, a valve provided in a carrier gas flow path through which a carrier gas flows, and a heating vaporizing means and a control means for controlling the valve are provided. At the time of the purge setting set in the control means, the control means controls the heating vaporization means and the valve to heat the mercury collection tube to 300 ° C. to 800 ° C. and collect the mercury. A mercury atomic fluorescence analyzer has been proposed in which a carrier gas is passed through a tube to purge the mercury collection tube (see Patent Document 5).

Japanese Unexamined Patent Publication No. 6-241990 Japanese Unexamined Patent Publication No. 2002-168773 Japanese Unexamined Patent Publication No. 2004-53294 Japanese Patent Application Laid-Open No. 2003-202290 Japanese Unexamined Patent Publication No. 2015-161636

Among the above-mentioned mercury concentration measuring devices, the mercury atom fluorescence analyzer shown in Patent Document 5 is said to enable highly accurate analysis of the mercury concentration.

By the way, when measuring the concentration of mercury contained in a mixture of hydrocarbons such as crude oil, it is possible to analyze the mercury in the crude oil as it is by using the above-mentioned method, but the crude oil is usually divided into each petroleum fraction. Since it is fractionated, it is conceivable to fractionate into each fraction and then measure the mercury concentration in each fraction.
However, as a result of examination by the present inventors, the amount of mercury obtained by analyzing the mercury in the crude oil as it is and the amount of mercury in the crude oil calculated based on the amount of mercury in each fractional distillation obtained by fractionating the crude oil. It turned out that the quantity was not always consistent.
Further, in the first place, conventionally, a method for measuring how mercury is distributed in each fraction obtained by fractionating crude oil has not been known.

Under such circumstances, the present invention can appropriately and easily measure the mercury concentration in a hydrocarbon mixture when a hydrocarbon mixture having a wide boiling point range is fractionated, and the mercury contained in the hydrocarbon mixture can be measured appropriately and easily. It is an object of the present invention to provide a pretreatment method for measuring the concentration of a hydrocarbon and a method for measuring the concentration of mercury contained in a hydrocarbon mixture.

As a result of diligent studies by the present inventors in order to achieve the above object, it is a pretreatment method for measuring the concentration of mercury contained in the hydrocarbon mixture, and the hydrocarbon mixture is fractionated under normal pressure. Pretreatment for measuring the concentration of mercury contained in a hydrocarbon mixture, which is characterized by being separated into a plurality of fractions and each of the obtained fractions is cooled under a temperature condition of 0 ° C. or lower. It has been found that the above object can be achieved by the method, and the present invention has been completed based on this finding.

That is, the present invention
(1) A pretreatment method for measuring the concentration of mercury contained in a hydrocarbon mixture.
The hydrocarbon mixture is subjected to a fractional distillation treatment under normal pressure to separate it into a plurality of fractions.
A pretreatment method for measuring the concentration of mercury contained in a hydrocarbon mixture, which comprises cooling each of the obtained fractions to 0 ° C. or lower.
(2) The pretreatment method according to (1) above, wherein the fractional distillation treatment is carried out by a distillation apparatus in which the portion in contact with the hydrocarbon mixture is entirely made of a glass member.
(3) The distillate contains at least a part of the components whose distilling temperature at the time of fractionation is 30 ° C. to 140 ° C., and the difference between the minimum temperature and the maximum distilling temperature is 5 to 150 ° C. The pretreatment method according to (1) or (2) above, which obtains a certain fraction.
(4) A method for measuring the concentration of mercury contained in a hydrocarbon mixture.
The hydrocarbon mixture is subjected to a fractional distillation treatment under normal pressure to separate it into a plurality of fractions.
With each fraction obtained cooled to 0 ° C or lower,
The concentration of mercury in each fraction is measured with a mercury concentration measuring device,
A hydrocarbon mixture characterized by calculating the concentration of mercury in the hydrocarbon mixture based on the concentration of mercury in each of the obtained fractions and the distillation yield of each fraction at the time of the fractional distillation. Method for measuring the concentration of contained mercury,
(5) The measuring method according to (4) above, and (6) the fraction. The above (4) for obtaining a fraction containing at least a part of the components having a distillation temperature of 30 ° C. to 140 ° C. and having a difference between the minimum temperature and the maximum temperature of the distillation temperature of 5 to 150 ° C. ) Or (5).

According to the present invention, when a hydrocarbon mixture having a wide boiling point range is fractionated, the concentration of mercury in the hydrocarbon mixture can be appropriately and easily measured, and the concentration of mercury contained in the hydrocarbon mixture can be determined. A pretreatment method for measurement and a method for measuring the concentration of mercury contained in a hydrocarbon mixture can be provided.

It is a schematic diagram which shows the morphological example of the distillation apparatus used in this invention.

First, a pretreatment method for measuring the concentration of mercury contained in the hydrocarbon mixture according to the present invention will be described.
The pretreatment method according to the present invention is a pretreatment method for measuring the concentration of mercury contained in a hydrocarbon mixture.
The hydrocarbon mixture is subjected to a fractional distillation treatment under normal pressure to separate it into a plurality of fractions.
It is characterized in that each of the obtained fractions is cooled under a temperature condition of 0 ° C. or lower.

In the pretreatment method according to the present invention, the hydrocarbon mixture to be pretreated includes crude oil, condensate, naphtha, gasoline composition, kerosene composition, light oil composition, heavy oil composition containing light components, and petroleum refining equipment. Examples thereof include intermediate oil obtained in.
Specific examples of the intermediate oil obtained by the petroleum refining apparatus include naphtha and gas oil obtained by a hydrogenation generator, cracked naphtha and cracked gas oil obtained by a coker device and a fluidized catalytic cracking device, and the like.

In the pretreatment method according to the present invention, the constituent components of the hydrogen mixture to be pretreated are not particularly limited, but in addition to various hydrogen compounds, oxygen-containing hydrocarbon compounds, nitrogen-containing hydrocarbon compounds, and sulfur-containing compounds are not particularly limited. One or more selected from hydrocarbon compounds and the like can be mentioned.

In the pretreatment method according to the present invention, the hydrocarbon mixture to be pretreated is preferably -40 to 180 ° C., although the initial distillation point (IBP) in atmospheric distillation is not particularly limited. The temperature of about 160 ° C. is more preferable, and the temperature of −20 to 140 ° C. is even more preferable.
A hydrocarbon mixture having an initial distillation point (IBP) of more than 250 ° C. is difficult to distill by atmospheric distillation, and is therefore not suitable as a pretreatment target in the present invention.

In the pretreatment method according to the present invention, the hydrocarbon mixture to be pretreated has an end point (EP) in atmospheric distillation, which is not particularly limited, but is preferably 30 ° C. or higher, preferably 50 ° C. or higher. Is more preferable, and those having a temperature of 70 ° C. or higher are even more preferable.
The upper limit of the end point (EP) in atmospheric distillation is not particularly limited, but since the measurement limit value when the hydrocarbon mixture is gas chromatographed is 750 ° C, the end point (EP) in atmospheric distillation is usually 750 ° C or lower. Will be.

In addition, in this application document, IBP and EP mean the distillation temperature in atmospheric distillation measured by JIS K2254: 1998 "petroleum product-distillation test method".

In the pretreatment method according to the present invention, the hydrocarbon mixture to be pretreated is not particularly limited in mercury concentration in terms of metallic mercury (mercury atom), but is preferably 0.005 to 3000 ng / ml. It is more suitable that it is 0.01 to 2000 ng / ml, and more suitable that it is 0.05 to 1500 ng / ml.

In the pretreatment method according to the present invention, the hydrocarbon mixture is subjected to a fractional distillation treatment to separate it into a plurality of fractions.

In the pretreatment method according to the present invention, when a hydrocarbon mixture is subjected to a fractional distillation treatment and separated into a plurality of fractions, it is preferable to fractionate into a total of 2 to 10 fractions and 3 to 10 fractions. It is more preferable to fractionate into the distillate of 4 to 10, and it is more preferable to distill into the distillate of 4 to 10.
The above fraction is preferably defined by the boiling point range of the hydrocarbon mixture, and specifically, as a result of defining each fraction so as to be within the range of the difference between the minimum temperature and the maximum temperature described below. It is preferably a determined fraction.

In the pretreatment method according to the present invention, when a hydrocarbon mixture is subjected to a fractional distillation treatment and separated into a plurality of fractions, the difference between the minimum temperature and the maximum temperature of the distilling temperature at the time of distillation of each obtained fraction is obtained. Is preferably 5 to 150 ° C, more preferably 10 to 100 ° C, and even more preferably 20 to 80 ° C.

In the pretreatment method according to the present invention, when a hydrocarbon mixture is subjected to a fractional distillation treatment and separated into a plurality of fractions, the resulting distillate has a distillation temperature of 30 ° C. to 140 ° C. at the time of fractional distillation. Those containing at least a part of a certain component are preferable, and those containing at least a part of the components having a distillation temperature of 50 ° C. to 120 ° C. at the time of fractional distillation are more preferable.

In the pretreatment method according to the present invention, at least a part of the components whose distilling temperature at the time of fractional distillation is 30 ° C. to 140 ° C. is contained, and the difference between the minimum temperature and the maximum distilling temperature is contained. It is preferable to obtain a fraction having a temperature of 5 to 150 ° C.

It is known that the boiling point of mercury is 357 ° C, but as a result of examination by the present inventors, a distillate containing at least a part of a component having a distilling temperature of 30 ° C to 140 ° C at the time of fractional distillation is known. Fractional distillation was found to contain a high concentration of mercury in the hydrocarbon mixture, even though the distilling temperature of the constituents was significantly different from the boiling point.
Therefore, in the pretreatment method according to the present invention, at least the lower limit value and the upper limit value of the distilling temperature are within the above temperature range when the fractional distillation treatment is performed on the hydrocarbon mixture to separate them into a plurality of fractions. A fraction containing at least a part of the components whose distilling temperature is 30 ° C to 140 ° C at the time of fractional distillation is obtained, and the concentration (measured value) of mercury in the fraction and the distillation at the time of fractionation are obtained. By calculating the mercury concentration using the yield, and if necessary, the density of each fraction and the density of the fractional distillation target, the concentration of mercury in the fractional distillation mixture (approximate value) can be easily obtained. Can be calculated in.

In the pretreatment method according to the present invention, the mercury concentration in each fraction can be appropriately measured even if a hydrocarbon mixture having a wide boiling point range is fractionated.
For example, when a hydrocarbon mixture is fractionated into a plurality of fractions, the yield of fraction F1 containing at _least a part of the components having a distillation temperature of 30 ° C. to 140 ° C. The mass ratio to the amount of the obtained hydrocarbon mixture is a ₁ (mass%), and the mercury concentration (measured value) in the fraction F ₁ is b ₁ (ng / ml). Further, the density of the hydrocarbon mixture is d ₀ (g / ml 15 ° C.), and the density of the fraction F ₁ is d ₁ (g / ml 15 ° C.).
In this case, the concentration A ₁ (ng / ml) of mercury contained in the fraction F ₁ is calculated by the following formula.
A ₁ (ng / ml) = {(a _1/100 ) x b ₁ x (1 / d ₁ )} x d ₀
When there is no fraction containing a component having a distillation temperature of 30 ° C to 140 ° C other than the fraction F ₁ , the above-mentioned mercury concentration A ₁ (ng / ml) is used as the concentration of mercury in the hydrocarbon mixture. Can be estimated.
If there is a distillate containing at least a part of the components having a distilling temperature of 30 ° C. to 140 ° C. _other than the distillate F1, the concentration of mercury in the distillate can be calculated in the same manner. The sum of the concentrations of mercury in each fraction can be estimated as the concentration of mercury in the hydrocarbon mixture.
By comparing the mercury concentration of the hydrocarbon mixture thus obtained with the mercury concentration of the hydrocarbon mixture measured without distillation, it is possible to easily confirm whether the mercury concentration of each distillate can be appropriately measured. can.

In the pretreatment method according to the present invention, when the mercury component contained in the hydrocarbon mixture to be pretreated is organic mercury such as dimethylmercury or diethylmercury, these are heated during fractional distillation. Generates metallic mercury (mercury atom).
Therefore, regardless of the compound form of mercury contained in the hydrocarbon mixture, it is considered that it is contained exclusively as metallic mercury (mercury atom) in each of the obtained fractions.

In the pretreatment method according to the present invention, the type of distillation apparatus for fractional distillation treatment is not particularly limited, and batch type (batch type) distillation apparatus, continuous distillation apparatus and the like can be used.

In the pretreatment method according to the present invention, it is preferable that the fractional distillation treatment is carried out by a distillation apparatus in which the portion in contact with the hydrocarbon mixture is entirely made of a glass member.

FIG. 1 is a schematic view showing an example of the distillation apparatus.
The distillation apparatus 1 shown in FIG. 1 includes a flask F with a temperature sensor in which a hydrocarbon mixture is charged, a mantle heater H with a temperature sensor arranged below the flask F to heat the flask F, and a mantle heater H. A rectifying column R with a temperature sensor that fractionates the vaporized hydrocarbons, a condenser C equipped with a cooling circulator CY that cools the distillate distilled from the rectifying column R, and a condenser C. It has a cold trap T into which the gaseous fraction cooled in the above flow flows in, and a receiver I in which the liquid fraction also cooled by the condenser C flows down through the buffer container B and is held.

In each member constituting the distillation apparatus 1 shown in FIG. 1, the members (flask F, rectification column R, condenser C, cold trap T, buffer container B, receiver I) that come into contact with the hydrocarbon mixture are all made of glass. It is made of members, and each member is formed of a ground joint, and the distillation valve V, the cock K, and the like arranged between the rectification column R and the condenser C are also made of glass.

As described above, in the pretreatment method according to the present invention, the adsorption of mercury components is suppressed by fractional distillation using a distillation apparatus in which all the portions in contact with the hydrocarbon mixture are made of glass members. The fractional distillation treatment can be suitably performed while reducing the loss (impairment) of mercury in each of the obtained fractions.

In the pretreatment method according to the present invention, the hydrocarbon mixture is subjected to fractional distillation treatment under normal pressure to separate it into a plurality of fractions, and the concentration of mercury in each fraction can be appropriately and easily measured. ..

In the pretreatment method according to the present invention, each fraction obtained by fractional distillation is cooled to 0 ° C. or lower.

In the pretreatment method according to the present invention, each fraction obtained by fractional distillation is cooled to 0 ° C. or lower, preferably -100 to 0 ° C., more preferably -80 to 0 ° C.

In the pretreatment method according to the present invention, the method for cooling each fraction obtained by the fractional distillation treatment is not particularly limited.

For example, in the case of fractional distillation using the distillation apparatus shown in FIG. 1, a cold trap T or a receiver I containing each fraction obtained by the fractional distillation is placed in a dewar bottle D containing a coolant. By immersing, each distillate can be suitably cooled.

The cooling agent is not particularly limited, and examples thereof include dry ice and those obtained by adding dry ice to various organic solvents such as ethanol.

As described above, the boiling point of mercury is known to be 357 ° C., but as a result of examination by the present inventors, a distillate containing mercury is actually distilled at a temperature significantly lower than the above boiling point. It turned out to be.
In the present invention, by cooling each fraction obtained by the fractional distillation treatment to 0 ° C. or lower, the volatilization of mercury from each obtained fraction is suitably suppressed, and an analysis error at the time of measuring the mercury concentration is obtained. Can be suitably suppressed.

According to the present invention, when a hydrocarbon mixture having a wide boiling point range is fractionated, the concentration of mercury in the hydrocarbon mixture can be appropriately and easily measured, and the concentration of mercury contained in the hydrocarbon mixture can be determined. A pretreatment method for measurement can be provided.

Next, a method for measuring the concentration of mercury contained in the hydrocarbon mixture according to the present invention will be described.
The method for measuring the concentration of mercury contained in the hydrocarbon mixture according to the present invention is as follows.
The hydrocarbon mixture is subjected to a fractional distillation treatment under normal pressure to separate it into a plurality of fractions.
With each fraction obtained cooled to 0 ° C or lower,
The concentration of mercury in each fraction is measured with a mercury concentration measuring device,
It is characterized in that the concentration of mercury in a hydrocarbon mixture is calculated based on the concentration of mercury in each of the obtained fractions and the distillation yield of each fraction at the time of the fractional distillation.

In the method for measuring the concentration of mercury contained in a hydrocarbon mixture according to the present invention, a step of performing a fractional distillation treatment on a hydrocarbon mixture under normal pressure to separate it into a plurality of fractions, and 0 for each obtained fraction. The details of the step of cooling to ℃ or less are as described in the pretreatment method for measuring the concentration of mercury contained in the hydrocarbon mixture according to the present invention.

In the method for measuring the concentration of mercury contained in the hydrocarbon mixture according to the present invention, the concentration of mercury in each fraction is measured in a state where each fraction obtained by fractional distillation is cooled to 0 ° C. or lower. Measure with a concentration measuring device.

In the method for measuring the concentration of mercury contained in the hydrocarbon mixture according to the present invention, the method for measuring the concentration of mercury in each fraction with a mercury concentration measuring device is not particularly limited, and a known method may be adopted. can.

In the method for measuring the concentration of mercury contained in a hydrocarbon mixture according to the present invention, a mercury concentration measuring device using an atomic fluorescence analysis method is preferable as the mercury concentration measuring device for measuring the concentration of mercury in each fraction.

In the method for measuring the concentration of mercury contained in a hydrocarbon mixture according to the present invention, when the mercury concentration in each distillate is measured using a mercury concentration measuring device using an atomic fluorescence analysis method, ASTM standard: UOP938-10. It is preferable to measure by the method specified in (Total Mercury and Mercury Species in Liquid Hydrocarbons).

In the method for measuring the concentration of mercury contained in the hydrocarbon mixture according to the present invention, it is further necessary based on the concentration of mercury in each fraction obtained by the above measurement and the distillation yield of each fraction at the time of the above fractional distillation. The concentration of mercury in the hydrocarbon mixture is calculated using the density of each fraction and the density of the hydrocarbon mixture to be fractionated.

For example, the yield of each fraction (mass ratio to the amount of the hydrocarbon mixture to be fractionated) when the hydrocarbon mixture is fractionated into four fractions is a ₁ (mass%), respectively. a ₂ (% by mass), a ₃ (% by mass) and a ₄ (% by mass) (however, a ₁ + a ₂ + a ₃ + a ₄ = 100% by mass), and the mercury concentration in each fraction (measured value). ) Are b ₁ (ng / ml), b ₂ (ng / ml), b ₃ (ng / ml) and b ₄ (ng / ml), respectively. The density of the hydrocarbon mixture was d ₀ (g / ml 15 ° C), and the density of each of the above fractions was d ₁ (g / ml 15 ° C), d ₂ (g / ml 15 ° C), d ₃ respectively. (G / ml 15 ° C.) and d ₄ (g / ml 15 ° C.).
In this case, the concentration A (ng / ml) of mercury contained in the hydrocarbon mixture is calculated by the following formula.
A (ng / ml) = {(a _1/100 ) x b ₁ x (1 / d ₁ ) + (a _2/100 ) x b ₂ x (1 / d ₂ ) + (a _3/100 ) x b ₃ x (1 / d ₃ ) + (a _{4/100) x b 4 x} (1 / d ₄ )} x d ₀

In the present invention, the concentration of mercury contained in the hydrocarbon mixture can be measured in this way.

In the method for measuring the concentration of mercury contained in a hydrocarbon mixture according to the present invention, the hydrocarbon mixture is subjected to a fractional distillation treatment under normal pressure to separate it into a plurality of fractions, and each fraction obtained is separated into a plurality of fractions at 0 ° C. By cooling to the following, the volatilization of mercury from each of the obtained fractions can be suitably suppressed, and the analysis error at the time of measuring the concentration of mercury can be suitably suppressed.
Therefore, in the method for measuring the concentration of mercury contained in the hydrocarbon mixture according to the present invention, the concentration of mercury in the hydrocarbon mixture can be appropriately and easily adjusted even when the hydrocarbon mixture having a wide boiling point range is fractionated. Can be measured.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

(Example 1)
Using sample A (15 ° C. density 0.7979 g / cm ³ ) as a hydrocarbon mixture and using a glass older-show distillation apparatus having the form shown in FIG. 1 (the number of theoretical stages of a rectification column is 5), fraction 1 Distillation separation into (distillation temperature: above the initial distillation point and below 30 ° C.), fraction 2 (distillation temperature: 30 ° C. to 80 ° C.), and fraction 3 (distillation temperature: over 80 ° C. and below 140 ° C.). The residue remaining in the flask was used as the flask residue, and the receiver or cold trap containing each fraction was cooled and stored in a dual bottle (temperature: -66.5 ° C.) containing ethanol containing dry ice as a coolant. ..
After the distillation was completed, each fraction that had been cooled and stored was taken out from the Dewar bottle, and the concentration of mercury in each fraction was measured according to the ATM standard UOP938: 10 using a mercury concentration measuring device (PE-1000 manufactured by Nippon Instruments Co., Ltd.). ..
As a result, since the mercury concentration in the fraction 1 and the flask residue was below the lower limit of quantification, the mercury concentration was considered to be 0.00 ng / ml. In fractions 2 and 3, the mercury concentrations were 7 ng / ml and 9 ng / ml, respectively. The 15 ° C. densities of fraction 2 and fraction 3 were 0.6629 g / ml and 0.7366 g / ml, respectively.
Since the yields of the distillate 3 and the flask residue were 8.4% by mass and 15.9% by mass, respectively, with respect to the charged sample (the amount of sample A subjected to the distillation treatment), the samples subjected to the distillation treatment were used. The mercury concentration in A is 2.3 ng / ml {0.00 (ng / g) + 7 (ng / ml) × (1 / 0.6629 (ml / g)) × 0.084 × 0.7979 (g / g / It was calculated as (ml) + 9 ng / ml x (1 / 0.7366 (ml / g)) x 0.159 x 0.7979 (g / ml) + 0.00 (ng / g)}. The results are shown in Table 1.

(Example 2)
Except for using sample B (15 ° C. density 0.9207 g / cm ³ ) as a hydrocarbon mixture and cooling and storing using a dual bottle (temperature -75.3 ° C.) whose temperature was controlled by adjusting the amount of dry ice input. Measured the concentration of mercury contained in the hydrocarbon mixture by the same method as in Example 1.
As a result, the mercury concentration in the distillate 1 (distillation temperature: above the initial distillate point and below 30 ° C.) and the flask residue are both below the lower limit of quantification, so that the mercury concentration is 0.00 ng / ml. I considered it. In the fractions 2 and 3, the mercury concentrations were 27 ng / ml and 70 ng / ml, respectively. The 15 ° C. densities of the fraction 3 and the flask residue were 0.6555 g / ml and 0.7362 g / ml, respectively.
Since the yields of the distillate 3 and the flask residue were 7.4% by mass and 5.3% by mass, respectively, with respect to the charged sample (the amount of sample B subjected to the distillation treatment), the samples subjected to the distillation treatment were used. The mercury concentration in B is 7.4 ng / ml {(0.00 (ng / g) +27 (ng / ml) × (1 / 0.6555 (ml / g)) × 0.074 × 0.9207 (g). It was calculated as / ml) +70 (ng / ml) × (1 / 0.7362 (ml / g)) × 0.053 × 0.9207 (g / ml) +0.00 (ng / g)}. Is shown in Table 1.

(Comparative Example 1)
In Example 1, each fraction obtained by the fractional distillation treatment was cooled and stored in a refrigerator (temperature: 3.0 ° C.) instead of being cooled and stored in a Dewar bottle at -66.5 ° C. , The concentration of mercury in the hydrocarbon mixture was measured in the same manner as in Example 1.
However, the mercury concentration of the fraction 1 to the flask residue obtained by the fractional distillation treatment was below the lower limit of quantification, and the mercury concentration could not be determined. The results are shown in Table 1.

(Comparative Example 2)
In Example 2, except that each fraction obtained by the fractional distillation treatment was cooled and stored in a refrigerator (temperature: 3.0 ° C) instead of being cooled and stored in a Dewar bottle at −75.3 ° C. , The concentration of mercury in the hydrocarbon mixture was measured in the same manner as in Example 2.
However, the mercury concentration of the fraction 1 to the flask residue obtained by the fractional distillation treatment was below the lower limit of quantification, and the mercury concentration could not be determined. The results are shown in Table 1.

In addition, the mercury concentration measuring device (PE-1000 manufactured by Nippon Instruments Co., Ltd.) was used as it was without performing the pretreatment for fractional distillation and cooling treatment of the sample A used in Example 1 and Comparative Example 1, and the ASTM standard UOP938: 10 was used. The mercury concentration was measured by 2.6 ng / ml.
Further, the mercury concentration measuring device (PE-1000 manufactured by Nippon Instruments Co., Ltd.) was used as it was without performing the pretreatment for fractional distillation and cooling treatment of the sample B used in Example 2 and Comparative Example 2, and the ATM standard UOP938: 10 was used. When the mercury concentration was measured with 8.9 ng / ml.
The results are also shown in Table 1.

From Table 1, in Examples 1 and 2, the hydrocarbon mixture was subjected to a fractional distillation treatment under normal pressure to separate it into a plurality of fractions, and each of the obtained fractions was cooled to 0 ° C. or lower. It has been processed. Since the total mercury concentration calculated from the mercury concentration of each fraction subjected to the pretreatment is almost the same as the total mercury concentration measured without the pretreatment, it is a hydrocarbon mixture having a wide boiling point range. It can be seen that the concentration of mercury contained in the hydrocarbon mixture can be appropriately and easily measured even when the fractional distillation treatment is performed.

On the other hand, from Table 1, in Comparative Examples 1 and 2, since the fractional distillation treatment and the pretreatment for cooling the obtained fractions to 0 ° C. or lower were not performed, the mercury concentration of each fractional distillation was appropriate. It turns out that it cannot be measured.

According to the present invention, the concentration of mercury contained in a hydrocarbon mixture can be appropriately and easily measured even when a hydrocarbon mixture having a wide boiling point range is fractionated. A pretreatment method for measuring a hydrocarbon and a method for measuring the concentration of mercury contained in a hydrocarbon mixture can be provided.

F: Flask with temperature sensor H: Mantle heater with temperature sensor R: Tightening column with temperature sensor C: Condenser T: Cold trap B: Buffer container B
I: Receiver V: Distillation valve K: Cock

Claims (6)

A pretreatment method for measuring the concentration of mercury contained in a hydrocarbon mixture.
The hydrocarbon mixture is subjected to a fractional distillation treatment under normal pressure to separate it into a plurality of fractions.
A pretreatment method for measuring the concentration of mercury contained in a hydrocarbon mixture, which comprises cooling each of the obtained fractions to 0 ° C. or lower. The pretreatment method according to claim 1, wherein the fractional distillation treatment is carried out by a distillation apparatus in which the portion in contact with the hydrocarbon mixture is entirely made of a glass member. The fraction contains at least a part of the components whose distilling temperature is 30 ° C. to 140 ° C. at the time of fractional distillation, and the difference between the minimum temperature and the maximum distilling temperature is 5 to 150 ° C. The pretreatment method according to claim 1 or 2. A method for measuring the concentration of mercury contained in a hydrocarbon mixture.
The hydrocarbon mixture is subjected to a fractional distillation treatment under normal pressure to separate it into a plurality of fractions.
With each fraction obtained cooled to 0 ° C or lower,
The concentration of mercury in each fraction is measured with a mercury concentration measuring device,
It is contained in a hydrocarbon mixture characterized by calculating the concentration of mercury in the hydrocarbon mixture from the concentration of mercury in each of the obtained fractions and the distillation yield of each fraction at the time of the fractional distillation. Method for measuring the concentration of mercury. The measuring method according to claim 4, wherein the fractional distillation treatment is carried out by a distillation apparatus in which the portion in contact with the hydrocarbon mixture is entirely made of a glass member. The fraction contains at least a part of the components whose distilling temperature is 30 ° C. to 140 ° C. at the time of fractional distillation, and the difference between the minimum temperature and the maximum distilling temperature is 5 to 150 ° C. The measuring method according to claim 4 or 5.

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