JPS6040197A - Extraction of paraffin - Google Patents

Abstract

PURPOSE:To produce n-paraffin having especially high purity, easily and economically, by adding methanol to a stock oil, and crystallizing and separating the higher paraffinic hydrocarbon from the stock oil. CONSTITUTION:1pt.vol. of petroleum, sand oil, shale oil, liquefied coal oil, etc. is mixed with preferably >=2pts.vol. of methanol at normal temperature and pressure to effect the crystallization of >=16C paraffinic hydrocarbons, and the precipitated purely white crystal composed mainly of n-paraffin is filtered. The filtrate is separated into methanol and the residual oil, and the recovered methanol is recycled as the extraction solvent. Preferably the stock oil contains a certain amount of a methanol-soluble light fraction, e.g. the fraction having a boiling point of 160-538 deg.C reduced to normal pressure. EFFECT:A part of the <=16C paraffin can be recovered by a proper pretreatment of the stock oil.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for efficiently extracting paraffin contained in petroleum or coal-derived liquid oil.

Petroleum, sand oil, shale oil, coal-derived liquid oil (coal liquefied oil, etc.) are mixtures consisting of a large number of components, the main components of which are various hydrocarbons, but they also contain nitrogen, sulfur, and oxygen. Contains some heterogeneous compounds such as The main hydrocarbons are mostly paraffinic and naphthenic hydrocarbons, and also contain aromatic hydrocarbons, but their content ratios generally vary depending on the mixture.

When using a mixture with such a complex composition,
Usually, some kind of extraction or purification is carried out, such as distillation, chemical washing, solvent extraction, etc. Among these, solvent extraction is widely practiced as a method for separating aromatic components, paraffin, etc., particularly in petroleum refining, petrochemical industries, and the like. For example, various methods have been industrialized to separate aromatic components, such as the Yudetsukunu method, the Sulfon method, the Alloturupan method, and the Formex method.As for the separation of paraffins, the pour point of the lubricating oil is mainly used. Examples include the MEK dewaxing method and the propane dewaxing method, which were developed to reduce the amount of carbon used.

The MEK dewaxing method and the propane dewaxing method are types of solvent dewaxing methods. uses liquefied propane and heats the mixture of raw material oil and propane under pressure to -80°
In this method, paraffin is separated by cooling to about 1000 ℃.

Similar to the MEK dewaxing method, propane dewaxing method, etc., this invention is a method for extracting pufffins from hydrocarbon mixed oil using a solvent, and its main purpose is to extract highly pure carbon at room temperature and normal pressure. The object of the present invention is to economically obtain n-paraffins having a number of 16 or more.

The method for extracting pufffins according to the present invention includes adding methanol to a hydrocarbon mixed oil, crystallizing and precipitating paraffinic hydrocarbons having 16 or more carbon atoms, and extracting the pufffin hydrocarbons from a mixture of raw material oil and methanol. It is characterized by separation.

That is, this invention is a method of crystallizing and precipitating mainly n-paraffins having 16 or more carbon atoms at normal temperature and normal pressure by using methanol as a solvent. Here, methanol was chosen as the solvent because the inventors had experimented with various solvents through trial and error and found that methanol was the most effective for extracting paraffin. be. The reasons for this are: 1) It has a special effect that cannot be obtained with other solvents, which is the ability to crystallize and precipitate back-in at room temperature and normal pressure;
It can be recycled; (1) it is industrially inexpensive and easy to prepare; and (2) it has a low boiling point and is almost nontoxic, so it is easy to handle.

Therefore, according to the method of this invention, industrially inexpensive methanol can be used, so it is very economical, and paraffin can be precipitated at room temperature and pressure, so extraction processing equipment is not required. This method is simplified, and since back-in can be crystallized and precipitated, highly pure U-back-in can be easily obtained by conventional methods such as filtration.

An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a block diagram showing an example of an apparatus for carrying out the method of this invention. First, feedstock oil (hydrocarbon mixed oil) (
4) is mixed with methanol (5) in the extraction step (1).

In this methanol extraction step, it is sufficient to simply add and mix methanol to the raw material oil at room temperature and normal pressure. When the raw material oil and methanol are mixed in this manner, mainly n-pufffins having 16 or more carbon atoms contained in the raw material oil are crystallized and precipitated. The amount of methanol added at this time is not particularly limited, but it is recommended that the amount of methanol added is at least 2 times the volume of the raw material oil.
This is preferable because crystallization of paraffin is promoted. In addition, it is preferable that the feedstock oil contains a certain amount of light methanol-soluble fraction, for example, with a boiling point of 160 to 58
An 8°C fraction or a 200-450°C fraction is suitable as the raw material oil.

The mixed liquid (6) of raw material oil and methanol mixed in the extraction step (1) is passed through the filtration step (2) to extract crystallized paraffin (7
). Paraffin extracted with methanol is
Generally, it has a pure white crystal appearance, and most of its composition is n-puffin. On the other hand, the filtrate (8) after paraffin separation is separated into methanol (5) and residual oil (9) in the methanol recovery step (3), and the recovered methanol is recycled and used as an extraction solvent. As a method for recovering methanol, a method of directly distilling the p-filtrate to recover methanol, a method of adding water to the filtrate and recovering methanol, etc. can be used.

This method of the invention is particularly suitable for extracting n-paraffins with a carbon number of 16 or more, but it is possible to extract paraffins with a carbon number of 16 or more by lowering the extraction temperature or performing pretreatment. It is. As the pretreatment method, for example, a method can be used in which most of the aromatic components in the raw oil are removed using dimethynulfoxide or the like as a solvent.

Next, embodiments of the invention will be described.

[Example 1] As feedstock oil, coal hydrocracked oil with a boiling point of 200
~538°C fraction is used, 4ml for 2y of feedstock oil
When 1 liter of methanol was added and the mixture was lightly shaken at room temperature and pressure, white crystals were suspended and precipitated in the mixture. This mixed solution was filtered using quantitative F paper, washed with methanol, dried and weighed to obtain 0.14y crystals.

The obtained crystals were dissolved in cyclohexane and analyzed using an FID temperature-programming Ganuchromatograph.
As shown in the figure, it was found to be a high purity n-paraffin.

[Example 2] 10y of the same raw material oil as in Example 1 was mixed with 10y of cyclohexane.
ml and 80 ml of dimethyl sulfoxide in a separatory funnel, stirred thoroughly, and then left to stand to separate into two layers. Of these, only the upper layer was taken out quantitatively, and when 2 times the volume of methanol was added and mixed, crystals were precipitated in the mixed liquid. When this mixed solution was treated in the same manner as in Example 1, 0.92y crystals were obtained. As a result of analyzing the obtained crystals using a Ganuchromatography, it was found that the crystals were C8 to C32 paraffins as shown in FIG.

[Example 8] Same as Example 2, 10y of raw oil, 10m of cyclohexane
l! , 80 ml of dimethyl sulfoxide was placed in a separatory funnel, thoroughly stirred, and allowed to stand to separate into two layers.The lower layer was removed, and 80 ml of dimethyl sulfoxide was poured into the funnel, stirred, and allowed to stand. This operation was repeated four times to remove most of the aromatic components from the upper cyclohexane solution.
Then, cyclohexane was removed by evaporation from this cyclohexane solution layer, and the remainder was weighed and found to be 1.61 y. When the obtained residue was analyzed, as shown in FIG. 3, it contained a large amount of pufffins with a CI of 6 or less.

As is clear from the above examples (according to the method of this invention, it is possible to economically obtain paraffin in a hydrocarbon mixed oil, especially high-grade pufffins having a carbon number of 16 or more, and the pretreatment of the feedstock oil is By applying this process, it is possible to obtain some paraffins having carbon atoms of 16 or less, which is extremely useful industrially.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the configuration of an apparatus for carrying out the method of this invention, FIG. 2 is a chart showing the results of Example 1 of this invention, and FIG. 8 is a chart showing the results of Example 2 of the same. , FIG. 4 is a chart showing the results of Example 3. 1... Extraction process, 2... Filtration process, 3... Methanol recovery process, 4... Raw material oil, 5... Methanol,
6...Mixed liquid, 7...B/2F, 8...P filtrate, 9...Residual oil. Applicant: Sumitomo Metal Industries, Ltd. Figure 1 Figure 3 Figure 4

Claims (1)

[Claims] In a method for extracting paraffin from a hydrocarbon mixed oil, methanol is added to and mixed with the raw oil, paraffinic hydrocarbons having 16 or more carbon atoms are crystallized, and the paraffinic hydrocarbons are extracted from the mixture of the raw oil and methanol. A method for extracting buff-in characterized by separating.