JPH0150356B2 - - Google Patents

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. It contains some hetero 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 a mixture with such a complex composition is used, some kind of extraction or purification is usually performed, such as distillation, chemical cleaning, 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, etc. For example, various methods have been industrialized to separate aromatic components, such as the Judex method, sulforan method, allosolvan method, and Formex method, and methods for separating paraffin mainly involve lowering the pour point of lubricating oil. Examples include the MEK dewaxing method and the propane dewaxing method developed for this purpose. MEK dewaxing method and propane dewaxing method are types of solvent dewaxing method.
The MEK method uses a mixture of methyl ethyl ketone and toluene to separate paraffin at around -20°C, while the propane dewaxing method uses liquefied propane to heat a mixture of raw material oil and propane under pressure. This method separates paraffin by cooling it to around -30°C.

This invention is a method for extracting paraffin from hydrocarbon mixed oil using a solvent, similar to the MEK dewaxing method, propane dewaxing method, etc. mentioned above, 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-paraffin having a number of 16 or more.

The method for extracting paraffin according to this invention is to add methanol to a hydrocarbon mixed oil and mix the paraffin with a carbon number of 16
The above paraffinic hydrocarbons are crystallized and precipitated,
This method is characterized in that the paraffinic hydrocarbons are separated from a mixture of raw material oil and methanol.

In other words, this invention uses methanol as a solvent to reduce the number of carbon atoms at room temperature and pressure.
This is a method of crystallizing and precipitating mainly n-paraffins of 16 or more. 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 that it can crystallize and precipitate paraffin at room temperature and pressure, which is a special effect that cannot be obtained with other solvents, that it can be used cyclically, and that it is industrially inexpensive and readily available. It is easy to prepare, has a low boiling point, and
It has almost no toxicity and is easy to handle.

Therefore, according to the method of this invention, methanol, which is industrially inexpensive, 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. Furthermore, since paraffin can be crystallized and precipitated, highly pure n-paraffin can be easily obtained by a conventional method.

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, raw material oil (hydrocarbon mixed oil) 4 is mixed with methanol 5 in an 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 raw oil and methanol are mixed in this way, the number of carbon atoms contained in the raw oil is 16.
Mainly n-paraffin is crystallized and precipitated. The amount of methanol added at this time is not particularly limited, but it is preferred that the amount is at least 2 times the volume of the raw material oil, since crystallization of paraffin is promoted. Also,
It is preferable that the feedstock oil contains a certain amount of light methanol-soluble fraction, for example, a fraction with a normal pressure equivalent boiling point of 160 to 538°C, or a fraction with a boiling point of 200 to 450°C. suitable.

The mixed liquid 6 of raw material oil and methanol mixed in extraction step 1 is extracted with crystallized paraffin 7 in extraction step 2.
Separate. Paraffin extracted with methanol generally has a pure white crystalline appearance and is composed mostly of n-paraffin. On the other hand, the filtrate 8 after paraffin separation is separated into methanol 5 and residual oil 9 in a 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 filtrate to recover methanol, a method of adding water to the filtrate and recovering methanol, etc. can be used.

This invention method is particularly suitable for extracting n-paraffin with a carbon number of 16 or more, but it is possible to extract paraffin 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 may be used in which dimethysulfoxide or the like is used as a solvent to remove most of the aromatic components in the raw oil.

Next, embodiments of the invention will be described.

[Example 1] As feedstock oil, a boiling point 200-538°C fraction of coal hydrocracked oil was used. 4ml of methanol was added to 2g of feedstock oil, and the mixture was lightly shaken at room temperature and pressure. As a result, white crystals were suspended and precipitated in the mixed solution. Filter this mixture using quantitative paper,
After washing with methanol, drying and weighing,
0.14 g of crystals were obtained. The obtained crystals were dissolved in cyclohexane and analyzed using an FID heating gas chromatograph, and as a result, it was found to be a high purity n-paraffin as shown in FIG.

[Example 2] 10 g of the same raw material oil as in Example 1 was added to cyclohexane.
The mixture was placed in a separatory funnel together with 10 ml and 30 ml of dimethyl sulfoxide, stirred thoroughly, and 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, 0.92
A crystal of g was obtained. As a result of analyzing the obtained crystals with a gas chromatograph, as shown in Figure 2,
It was found to be a _C9 to _C32 paraffin.

[Example 3] Same as Example 2, 10g of raw oil, cyclohexane
10 ml of dimethyl sulfoxide and 30 ml of dimethyl sulfoxide were placed in a separatory funnel, thoroughly stirred, and allowed to stand to separate into two layers.The lower layer was removed, and another 30 ml of dimethyl sulfoxide was poured, stirred, and allowed to stand. This operation was repeated four times to remove most of the aromatic components from the upper layer of the cyclohexane solution, and then the cyclohexane was removed by evaporation from the cyclohexane solution layer, and the remainder was weighed and found to be 1.61 g. When the resulting residue was analyzed, it was found to contain a large amount of paraffin of _C16 or less, as shown in Figure 3.

As is clear from the above examples, according to the method of this invention, it is possible to economically obtain paraffin in hydrocarbon mixed oil, especially high-grade paraffin having 16 or more carbon atoms, and it is also possible to pre-treat the feedstock oil. number of carbons
Parts of paraffin below 16 are also obtainable and are 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. 3 is a chart showing the results of Example 2 of the same. , FIG. 4 is a chart showing the results of Example 3. DESCRIPTION OF SYMBOLS 1... Extraction process, 2... Extraction process, 3... Methanol recovery process, 4... Raw material oil, 5... Methanol, 6... Mixed liquid, 7... Paraffin, 8...
Superfluid, 9...Residual oil.

Claims (1)

[Claims] 1. In a method for extracting paraffin from a hydrocarbon mixed oil, methanol is added to and mixed with the raw material oil,
1. A method for extracting paraffin, which comprises crystallizing and precipitating paraffinic hydrocarbons having 16 or more carbon atoms, and separating the paraffinic hydrocarbons from a mixture of raw material oil and methanol.