JPS5926060A - Separating and sampling method of saturated hydrocarbon, olefinic hydrocarbon and aromatic hydrocarbon in hydrocarbon oil - Google Patents

Abstract

PURPOSE:To separate and sample quickly and exactly the satd. component, olefinic component and arom. component in a sample hydrocarbon oil, by providing metallic columns, a pump, etc. which withstand respectively high pressures and determining the partition points of the three components by using an indicator added to the sample or silica gel. CONSTITUTION:A sample hydrocarbon oil is drawn by an injection cylinder 8 into a sample loop 7, and a displacement solvent such as isopropyl alcohol or the like is fed from a vessel 1 through a high pressure-resistant pump 2, a three-way valve 5, and a six-way valve 6 to the loop 7 where the sample is passed through high pressure-resistant metallic columns 11 packed with silica gel to a flow cell 14 arranged to avoid the incorporation of foam. A small column 16 contg. a fluorescent indicator (JIS K 2536) or the like for analyzing the compsn. of petroleum products, i.e., hydrocarbons which is incorporated in a silica gel is placed in front of the inlet of the columns 11, and the point where the absorbancy increases sharply at each partition point of the components which are separated in order of the satd. component, the olefinic component, the aromatic component and the displacement component is detected with an autograph UV visible spectrophotometer 13, whereby the respective components are quickly and exactly separated and drawn. The three components contg. no displacement solvent are thus separated with high purity.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to hydrocarbon oils such as petroleum products, which contain saturated hydrocarbons (hereinafter referred to as saturated components), olefin hydrocarbons (hereinafter referred to as olefin components), and aromatic hydrocarbons (hereinafter referred to as olefin components).
The present invention relates to a method for separating and collecting aromatic compounds into three types (hereinafter referred to as aromatic components).

The hydrocarbons contained in hydrocarbon oils such as petroleum products are roughly divided into three compound types: saturated, olefin, and aromatic, so the composition of hydrocarbon oil is expressed by the content of these three compound types. This has become one of the most basic tests for hydrocarbon oils. However, in hydrocarbon oil containing olefins, it is difficult to separate and collect all three types of compounds, saturated, olefin, and aromatic, in amounts of several ml to enable various measurements with high purity. It was extremely difficult. This term not only makes precise and detailed analysis of catalytic cracking naphtha, one of the main raw materials for automotive Kallin, difficult, but also makes it difficult to analyze catalytic cracking naphtha, which is currently one of the main raw materials for automobile Kallin, and also makes it difficult to analyze olefins such as heavy oil cracked oil and oil shale oil, which are used as alternative fuels for petroleum. This also poses an obstacle to the research and development of hydrocarbon oils whose main constituents are

The present invention was developed against the background of the above, and its objective is to obtain a hydrocarbon oil with a relatively high olefin content, and to reduce the saturated content, olefin content, and aromatic content from hydrocarbon oil with a relatively high olefin content. The object of the present invention is to provide a method for separating and collecting all compound types in amounts of several ml with a purity level that can be subjected to more detailed analysis and testing. Previously attempted methods for the same purpose include high-performance liquid chromatography using microspherical silica gel as a packing material and n-hexane or fluorinated cyclic ether as an elution solvent. There is high-performance liquid chromatography, which combines a column loaded with cyclohexane and benzene as a packing material. However, these methods can only process a few hundred mg of sample at a time;
It takes a huge amount of time and effort to collect each compound type, and each compound type separated by these methods can only be collected diluted with the elution solvent, so the elution solvent must be removed by evaporation after collection. It is necessary to do so. Therefore, it is inevitable that low-boiling components in the sample will be lost by evaporation, and in particular, hydrocarbon oils from gasoline fractions have boiling points close to the elution solvent, making it impossible to apply such elution liquid chromatography. be.

Therefore, as a separation method, it is preferable to use displacement chromatography, which allows the components to be collected without an eluent, but known methods for displacement chromatography targeting hydrocarbon oils containing olefins include ASTM D2
003 was the only way. The purpose of this method is to separate and collect only the saturated component from a hydrocarbon oil with a boiling point of 221°C or less that contains olefin components, and the three compounds targeted by the present invention: saturated component, olefin component, and aromatic component. Although it is not originally suitable for separating and collecting all types, if you add an unspecified extension to this method and continue to flow out the sample after collecting the saturated component, the olefin component and aromatic component will flow out one after another. It is not impossible to perform separate sampling. However, this method (a) uses a long glass tube with a length of about 2.9 m, which makes handling such as cleaning extremely inconvenient; and (b) the column is made of glass, which poses a risk of rupture. Because of this, it is not possible to increase the pressure inside the column, and therefore the flow rate of the sample and replacement solvent cannot be increased, so separation takes an extremely long time, and it may not be possible to carry out the process due to the viscosity of the sample. It is impractical in many respects.

The present invention solves the above-mentioned problems and achieves good separation between the three types of compounds: saturated, olefin, and aromatic. The column is characterized by the use of metal pipes with sufficient pressure resistance so that the sample and replacement solvent can be safely flowed at a practically desirable high flow rate. In the present invention, a second feature of the measures taken to achieve good separation between the three compound types is that the column has sufficient pressure resistance and constant randomization to flow the sample and displacement solvent through the column. The solution is to use a liquid pump that can push out liquid at a flow rate of . By using a pump for liquid delivery, it is possible to precisely set and control the flow rate, as well as to send the liquid at a constant flow rate, which was not possible with the conventional displacement chromatography method of pressurizing the liquid with gas. became possible.

According to displacement chromatography that combines the above,
A quick and good separation of the saturated, olefin, and aromatic components of hydrocarbon oil, which could not be achieved in the past, can be easily achieved. Since they flow out one after the other, you can divide them into separate containers and collect them. Determining the split point between each compound type, i.e. when to replace each receiver, is an important part of this separation procedure;
In the present invention, one method to easily carry out is self-recording ultraviolet light
It is characterized in that the absorption intensity of the column effluent is continuously recorded using a visible spectrophotometer, and the dividing points are determined from the resulting chromatogram.

Among the components of hydrocarbon oil, the aromatic component itself strongly absorbs ultraviolet light, so if the detector is set to an appropriate wavelength in the ultraviolet region, for example 280 am, the dividing point between the olefin component and the aromatic component can be detected. can be immediately determined by the rapid increase in absorption intensity even when aromatic components are released. However, since the other components and the alcohols used as replacement solvents do not absorb any ultraviolet or visible light, the dividing points other than the dividing point between the olefin component and the aromatic component cannot be determined depending on the absorption intensity of the sample component itself. do not have. For this reason, in the present invention, an indicator that flows out between the saturated component and the olefin component and between the aromatic component and the displacement solvent and absorbs ultraviolet or visible light is added in advance to the sample or column. , a method is used to determine the dividing point based on the change in absorption intensity caused by the outflow of these indicators. As an indicator for this purpose, any substance with the above-mentioned properties can be used, but the most readily available one is hydrocarbon composition analysis of petroleum products (fluorescent indicator adsorption method, J.
G) Optical indicators for use in ISK 2536) are preferred. One component in this fluorescent indicator flows out near the dividing point between the saturated and olefin components, and exhibits absorption of ultraviolet light. If the wavelength of the detector is set to 280#m, the outflow will produce a clear peak in the chromatogram, so the dividing point can be clearly determined. Then, while the olefin component was flowing out, the wavelength of the peck detector was set to 280.
, :m, the division point between the olefin component and the aromatic component can be accurately determined due to the sudden increase in the light absorption intensity due to the outflow of the aromatic component as described above. In addition, the red dye, which is another component in this fluorescent indicator, flows out near the dividing point between the aromatic component and the replacement solvent, but since this dye has an absorption maximum near the wavelength of 500 em, the aromatic component flows out. By switching the wavelength of the detector to 5000-5 = 5,000-5 during the process, when the aromatic component that does not exhibit absorption at this wavelength flows out together with the dye or replacement solvent, the absorption intensity increases rapidly. , this dividing point can also be clearly determined.

However, in displacement chromatography, air bubbles cannot be mixed in the column effluent, so the flow cell through which the column effluent passes to measure the absorption intensity with a spectrophotometric detector is usually used in high-performance liquid chromatography. The micro-capacity flow cells that are used for direct connection to columns cannot be used because they generate a lot of noise due to air bubbles. The present invention is characterized by using a flow cell devised by the inventors in order to solve this difficulty. This flow cell is a siphon-type flow cell with an open inlet in the shape of a funnel, and by dropping the column effluent into the funnel, air bubbles escape into the atmosphere and only liquid flows through the flow cell. This is how it was done. By using this flow cell, the absorption intensity of the column effluent can be recorded without the influence of air bubbles.
It became possible to meet.

As another method to more easily determine the division of sample components, it is also possible to perform visual inspection similar to hydrocarbon composition analysis (e.g. (7) optical indicator adsorption method). As a method to ensure this, the present invention is characterized in that a column made of glass having a sufficient surface pressure of 4 at the outlet end of the column is connected and used as a column for determining the dividing point. This fissure column is filled with silica gel in the same way as the main column, which is a metal column. Otsu (Ma bunsho l)
The point can be easily determined by irradiating it with light from an ultraviolet lamp.

Next, in conventional displacement chromatography using silica gel as a packing material, the practitioner β clearly fills the column with silica gel and uses it), and the used silica gel is 1
It is customary to use (/1 A'1.) each time, and it is never practiced to use used silica gel repeatedly. However, when using a long column or connecting several columns, it requires a considerable amount of time and effort to fill the column with silica gel, and the quality of the packing affects the separation results. It is not a good idea to refill the battery every time as the battery is overflowing.

Furthermore, discarding used silica gel once only limits the range of silica gel that can be used for displacement chromatography from an economic point of view. Couldn't use it.

One of the features of the present invention is that the silica gel used in displacement chromatography can be regenerated in a simple manner while still being filled in the column and used repeatedly. In other words, the activity of silica gel, which is necessary for separating hydrocarbon oil into three types of compounds, saturated, olefinic, and aromatic, by displacement chromatography, can be completely recovered by appropriate regeneration treatment even after use. We discovered this and put the processing method to practical use. By implementing this regeneration method, all of the above-mentioned inconveniences caused by conventionally filling and disposing of silica gel each time can be solved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A more detailed explanation will be given below with reference to the drawings showing an apparatus suitable for carrying out the present invention.

FIG. 1 is an explanatory diagram of a chromatogram obtained when the present invention is carried out. Before explaining the present invention in detail, the apparatus will first be explained.

In Fig. 1, 1 is a container for the displacement solvent, 2 is a liquid pump, 3 is a pressure gauge, 4 is a conduit for introducing nitrogen gas, 5 is a three-way valve for switching between the displacement solvent and nitrogen residue, and 6 is a 6 direction valve, 7
is a sample measuring and introducing loop whose internal volume is equal to the amount of sample to be processed in one operation. Reference numeral 8 denotes a syringe barrel for trial injection, which is connected by a joint 9 to a six-way valve when introducing a sample.

10 is a stainless steel conduit with an inner diameter of about 0.5 mm, and 11 is a metal column. The amount of silica gel filled is sufficient to completely develop and retain the olefin and aromatic components of the sample to be treated.
Prepare a column with an appropriate inner diameter and length to satisfy the internal volume of the column or the required amount of light. The metal tube used in the column must have a pressure resistance of at least 150 kg/cm2. 12 is an air bath constant temperature bath capable of housing a column, 13 is a self-recording ultraviolet/visible spectrophotometer, 14 is an inlet and an outlet of a flow cell, and 15 is a receiver for collecting separated components. An example of the flow cell No. 4 is shown in detail in FIG. 16 is a small column filled with a small amount of commercially available silica gel containing a fluorescent indicator when used as an indicator for determining the dividing point. This small column and 1
3.14 is not necessary when the dividing point is determined visually, and a glass column for determining the dividing point is connected after 11.

Using the apparatus configured as above, the saturated content of hydrocarbon oil,
The method for separating and collecting the olefin and aromatic components will be described below.

First of all, as a preparation, apply the activated deer gel in advance to the column shown in Figure 1 II. Also, silica gel containing a fluorescent indicator was dry-injected into 16 small columns, and then connected as shown in the figure. At this time, the 16 small columns and the 6-way valve 6 are left unconnected. Set the 6-way valve 6 to the dotted line position, flush a suitable solvent to the loop 7 through 8.9 for cleaning, then set the 3-way valve 5 to the dotted line position to flow nitrogen gas from 5. Dry the entire flow path up to the small column inlet. After completing the above preparations, stop the nitrogen gas and
Connect the 6-way 6-way half flow, set the 6-way valve 6 to the position indicated by the dotted line, and fill the loop 7 with the sample. Next, the six-way valve 6 and the three-way valve 5 are set to the positions indicated by the solid lines, and the liquid feed pump 2 is started to flow the replacement solvent (for example, isopropyl alcohol). The sample in loop 7 and the fluorescent indicator in small column 16 are pushed by the displacement solvent from liquid pump 2 and enter the column, where they are developed and separated, then flow out from the end of the column and pass through 14 flow cells. Through the 15 receptacles (
This is coming out. 28 including the wavelength of the spectrophotometer of I3.
If the sample component is set to 0 mm, a romatochlam will be drawn on the recording paper as shown in FIG. 3 as the sample components flow out. In FIG. 3, A is a pulse-like noise caused by the column effluent entering the flow cell, and the recorder's indication immediately returns to the Haese line after this, indicating that the saturated amount is flowing out. B is the peak due to the fluorescent indicator component indicating the division point of the saturated olefin component, and C is the increase in the absorption intensity due to the outflow of the aromatic component 1ζ, and the recorder's indication is normally in a state where it has swung out. When the wavelength of the spectrophotometer is switched to 500 am at an appropriate time while the aromatics are flowing out, the reading on the recorder returns to the Hasslein. E
is a peak due to the fluorescent indicator component that indicates the splitting point of the aromatic displacing solvent. Arrows F, G, and H in Figure 3 are the dividing points of saturated olefin, olefin aromatic, and aromatic and substitution solvent, respectively. The dotted arrows F', G', and I-1', which corrected the lag due to volume, are the receiver replacement times, and up to F' is the saturated fraction, from F' to σ is the olefin fraction, and from G' to H' The aromatic fraction is collected in separate receivers. Note that when determining the dividing point visually using a glass column for determining the dividing point without using a spectrophotometer, the same operation as in the fluorescent indicator adsorption method may be used. The volume of each additional volume can be accurately determined by the scale lines on the receiver.

Next, a method for regenerating the silica gel in the column after performing the separation according to the above method will be described. Once the aromatic fraction has been collected using the above method, replace the replacement solvent container 1 in Figure 1 with a container containing methylene chloride, and adjust the pump flow rate to a level that is within the range that the pressure resistance of the column allows. Big Kikusi,
Pump methylene chloride. After methylene chloride has flowed out from the end of the column, methylene chloride in an amount approximately twice the column internal volume is further flowed, and then the pump is stopped. Then 3 in Figure 1
Set valve 5 at the position indicated by the dotted line and let the nitrogen scum flow through.
The temperature of the air bath constant temperature bath 12 is set to 150°C to 175°C.
Leave it alone. The time for leaving to stand varies depending on the internal volume of the column and the flow rate of nitrogen gas, but it is sufficient to leave it for about 3 to 8 hours after liquid droplets no longer come out from the column outlet. Through the above treatment, the silica gel in the column is regenerated and can be immediately reused. Also, if a sealing means is provided at the outlet and inlet of the column after regeneration, it can be used to release the seal even after being left for a long time. The contents of the silica gel containing a fluorescent indicator in the 16 small columns and the glass column for determining the dividing point when the dividing point is determined by visual inspection are re-introduced each time.

The present invention will be illustrated below with reference to Examples, but the present invention is not limited to these embodiments.

Example 1 Separation results of pure hydrocarbon mixture In an actual sample of hydrocarbon oil, it is difficult to determine the degree of separation between the two separated parts, and detailed evaluation of separation results is not possible. Therefore, a known amount of pure hydrocarbons was mixed together. The following is an example in which the separated samples were analyzed by gas chromatography, and the separation results were investigated.

B. Sample sample corresponding to Kallin fraction f4:, 1-hebutane, methylcyclohexane, ■-
Mixture of equal volumes of octene and toluene (saturated: 50 volumes, olefins: 25 volumes, aromatics: 25 volumes) Sample amount: Approximately 10 ml Column: Stainless steel, inner diameter 167 mm, length 5
00mm 1 piece, inner diameter 7, 6mm length 500mm 2 pieces, inner diameter 4. Q: One piece of 500mm length connected in series.

Silica gel: Davison No. 922 (particle size 7
(4 μ or less) Substitution solvent: Isopropyl alcohol Flow rate: 1 ml/min Required time: Approximately 2 hours Separation results: As shown in Table 1. ;3 volume, 1'
-tothycene 1 volume, ]-tetrathecene] volume, n-phthylhensene 1 volume, n-hexylhensen] volume (saturate content 60 volume part, olefin content 20 volume part, aromatic content 20 volume%) Sample amount: about 101 nt The column, silica gel, displacement solvent, flow rate, and required time are
Same as .

Separation results: As shown in Table 2.

Example 2 Separation results of actual samples Catalytic cracked naphtha was separated by the method of the present invention, and the approximate composition of each of the obtained two fractions was analyzed by ultraviolet absorption method, NMFt method, and mass spectrometry method, and the separation results were reported. An example is shown below.

Sample: Catalytic cracking naphtha Sample amount: Approximately 10 mt Column, silica gel, substitution solvent, flow rate, and required time are the same as in Example 1.

Separation results: As shown in Table 3.

Example 3. Regeneration of silica gel Example 1: The silica gel used in the meeting was regenerated by the method of the present invention, and when the sample of Example 1 was repeatedly separated, the separation results each time are as shown in Table 4. You can see that the results are obtained and that the regeneration is complete.

Sample, separation conditions: Example 1, same silica gel regeneration conditions for the nose: about 30 methylene chloride after use for separation
0 ml was pumped and washed, and nitrogen was aerated at 175°C for 8 hours (pressure cuff Kg/cm2)

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention, and is an explanatory diagram of a chromatogram obtained during the treatment. ■...Displacement solvent container, 2...Liquid pump, 3...
Pressure gauge, 4...Nitrogen gas introduction tube, 5.0.3-way half, 6...6-way half, 7.fist/sample loop, 8.
--Injection m, 9...Joint, 10e...Conduit, 1
]...Column, 12...Air bath constant temperature bath, 13...
Self-recording UV-visible spectrophotometer, 14...Flow cell (inlet and outlet), 15...Receiver, 16...Small force ram for indicator, 17...Flute-like part, 18...Transmission window (With quartz window plate), 19... Outlet, A... Pulse due to inflow of column effluent, B... Peak of indicator component indicating the division point of saturated and olefin components, C... Aromatic rise of absorption intensity due to inflow of D e I I @ wavelength 2804 @ m to 530 mm, E... peak of indicator component indicating the division point of aromatic component and displacement solvent, FlG, H. ...Dividing points on the chromatogram, F', G
', H'... Receiver exchange point, patent applicant Mitsubishi Oil Corporation

Claims (4)

[Claims] (1) A column made of a metal tube filled with silica gel that has a pressure resistance of at least 100 Kg/cm2 and a column that has a pressure resistance of at least 100 Kg/cm2 and a pressure resistance of 0.2 kg/cm2 or more.
Displacement chromatography is performed using a pump that can deliver the sample and displacement solvent at any flow rate above the mA/mi intake, and an indicator added to the sample or silica gel in advance is used to determine the separation point of sample components. A method for separating and collecting saturated hydrocarbons, olefin hydrocarbons, and aromatic hydrocarbons in hydrocarbon oil. (2) Determination of dividing points for sample components using a self-recording ultraviolet/visible spectrophotometer that continuously records the absorption intensity of the sample components or indicator flowing out of the column against ultraviolet light or visible light. A method for separating and collecting saturated hydrocarbons, olefin hydrocarbons, and aromatic hydrocarbons in hydrocarbon oil according to claim 1, characterized by: (3) A glass column filled with silica gel and having a pressure resistance of at least 50 Kg/cm is connected to the outlet end of the column. A method for separating and collecting saturated hydrocarbons, olefin hydrocarbons, and aromatic hydrocarbons in hydrocarbon oil according to claim 1, wherein the dividing point is determined visually under ultraviolet irradiation. (4) Saturated hydrocarbons, olefin hydrocarbons, and aromatic compounds in the hydrocarbon oil according to claim 1, characterized in that the spent silica kel is regenerated in the state filled in the column and used repeatedly. Method for separating and collecting hydrocarbons.