JPS6071687A - Processing method for coal-based heavy oil - Google Patents

Abstract

PURPOSE:To improve the yield of light oil and the useful compounds such as naphthalene, etc. contained therein, by hydrocracking a coal-based heavy oil in the presence of a catalyst, and keeping the liquid product obtained by cracking at a high temperature. CONSTITUTION:A coal-based heavy oil is subjected to the hydrocracking in the presence of preferably an iron compound (e.g. iron ore), the gaseous product is separated, and the remaining liquid product is maintained at a high temperature for a definite time interval to promote the reforming reaction of the liquid product and to effect the processing of the coal-based heavy oil. EFFECT:The yield of light oil and the valuable compound such as naphthalene, etc. contained therein from a coal-based heavy oil, can be improved easily and effectively, only by keeping the hot liquid product discharged from a vapor-liquid separation column to a high temperature.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to hydrocracking of coal-based heavy oil using a catalyst, and then maintaining the liquid product after the cracking at a high temperature for a period of time. , relates to a method for processing coal-based heavy oil that increases the yield of light oil and useful compounds such as naphthalene contained therein.

[Technical background of the invention and its problems] Conventionally, when treating coal-based heavy oil, the steps shown in FIG. 1 have been used. That is, coal-based heavy oil 10 is subjected to hydrocracking 18 under the addition of a catalyst 12 and hydrogen 14, and then a gas-liquid fraction of 9.18 is formed, and the gaseous product is cooled 20 to be irrigated as gas 22. ), on the other hand, the liquid product is separated into light oil 26 and heavy oil 28 by distillation 24.

The purpose of hydrogenation cracking is that coal-based heavy oil itself contains high polymer + () components produced by high-temperature thermal history, and has undesirable properties such as high viscosity and easy coking. Therefore, by hydrogenating it, it decomposes, becomes low molecular weight, turns into naphthyl, reduces aromaticity, lowers the viscosity of Tobuki oil, and improves its thermal stability and coking and ductile properties (□ 17I-.

However, as described above, coal-based heavy oil is a heavy oil that has undergone a high-temperature thermal history, so its hydrocracking reaction +5 is slow.

Chemical raw materials derived from coal include polynuclear aromatic hydrocarbon compounds such as naphthalene, methylnaphthalene, 7-notraceno, and carhatazole, and light oil produced by hydrocracking of coal-based heavy oil. Of course, it is desirable that these compounds be contained in large quantities.

Therefore, even if the conventional method is to increase the amount of hydrogen gas absorbed in the hydrocracking process in order to increase the yield of light oil, polynuclear aromatic hydrocarbon compounds such as naphthalene Some of the aromatic rings of the light oil become hydrogenated products, and the yield of polynuclear aromatic hydrocarbon compounds contained in the light oil decreases. Moreover,
The boiling point difference between a polynuclear aromatic hydrocarbon compound and its hydrogenated product is
For example, between naphthalene and Te] Lawan, each
The temperature is 11°C (18°C and 207°C), which is extremely small and difficult to separate using existing distillation equipment, requiring reforming equipment other than the distillation equipment. Usually, the reaction equipment for reforming has a reaction temperature of 450 to 510°C and a reaction pressure of +5-1.
50kg/cm', LH5V: 1-2. Operating conditions for circulating hydrogen (hydrogen/oil molar ratio) of 5 to IO must be used or a catalyst must be used, and if a reforming reaction is performed, not only the equipment cost increases but also the thermal efficiency is low.

[Object of the Invention] Therefore, the object of the present invention is to increase the yield of useful polynuclear aromatic compounds as well as the yield of light oil, and to provide an excellent heating efficiency.
Moreover, it is an object of the present invention to provide a method for processing coal-based heavy oil that brings advantages such as lower equipment costs.

[Structure of the Invention] To achieve this object, the present invention hydrocracks coal-based heavy oil using a catalyst, and after separating the gaseous products, maintains the liquid product at a high temperature for a period of time. It is characterized by promoting the reforming reaction of liquid products.

[Specific Examples of the Invention] As the coal-based heavy oil in the present invention, high-temperature tar or low-temperature tar that is produced as a by-product during coal carbonization can be used.

In this case, it is desirable to use a WB point of 270°C or higher. This is because it is better to remove the low boiling point fraction below 270° C. in advance, which is superior in hydrocracking efficiency and catalytic efficiency in the hydrocracking reaction, and is convenient for subsequent light oil separation.

As shown in FIG. 2, this coal-based heavy oil 10 is subjected to hydrocracking 16 in the presence of a catalyst 12 and hydrogen 14, as in the prior art. For this condition, 1 reaction temperature or 450
°C to 500 °C, and hydrogen pressure is 100 to 200 kg/cm
It is desirable to keep it at 'or higher.

FIG. 3 shows the relationship between the reaction temperature, light oil yield, and hydrogen gas absorption amount in the hydrocracking reaction of coal-based heavy oil. According to the same figure, when the reaction temperature is 450°C or lower, the light oil yield and the amount of hydrogen gas absorbed are almost constant;
They increase at temperatures above 0°C. This means that 450
It is suggested that below 450°C, hydrogenation reaction mainly proceeds, and above 450°C, hydrogenolysis reaction also proceeds. However, it is desirable to maintain the reaction temperature at 450°C or higher. On the other hand, if the reaction temperature exceeds 500°C, the coking reaction tends to proceed easily, which poses a problem when the finally obtained heavy oil is used as a raw material for carbon material.

On the other hand, the hydrogen pressure in the hydrocracking process is 100kg
If it is less than /crrf, the hydrogenation reaction of the aromatic ring will progress and explode, so the decomposition reaction following the hydrogenation reaction will not be sufficient, and as a result, the desired increase in light oil yield cannot be expected. Furthermore, if the hydrogen pressure exceeds 200 kg/cm', the amount of expensive hydrogen consumed increases, and the cost required for pressure-resistant equipment becomes relatively high.

As the catalyst used in the present invention, iron-based compounds are desirable.

Conventionally used catalysts are preferable because they are highly active and produce light oil, but they have a short lifetime and require a catalyst regeneration step. In this respect, catalysts in the hydrocracking of coal-based heavy oils are easily subject to
- Therefore, an iron-based catalyst that can be easily handled manually, inexpensively, and disposable is desirable.

As an iron-based catalyst, an iron-based compound such as red mud or iron ore is used in an amount of 1 to 10 WT% based on coal-based heavy oil, and as a co-catalyst, a sulfur compound is used in a proportion of 1-10 WTx based on coal-based heavy oil. It is preferable to use If it is less than 1%, the effect of the catalyst will not be significant, and if it exceeds 10%, the catalyst efficiency will deteriorate.

On the other hand, the amount of hydrogen acid added is 0.5 for coal-based heavy oil.
It is desirable to set it to ~3.5z.

The coal-based heavy oil that has undergone such a hydrocracking process is separated into raw material hydrogen, product gas, and liquid product through a gas-liquid separation process 18.

The invention is particularly characterized by maintaining 30 this liquid product at a high temperature.

As mentioned above, the temperature for hydrocracking coal-based heavy oil is preferably 450 to 500°C, but in the case of hydrogenated products,
Because it is easier to decompose compared to coal-based heavy oil,
The high temperature holding temperature is preferably slightly lower than the hydrogenolysis temperature, and the temperature range is preferably about 400 to 480°C. It is preferable to use the heat of the cooling process 2θ as this heat.

The holding pressure is preferably 15 to 150 kg/cm',
If it is less than 15 kg/cm', the yield of polynuclear aromatic hydrocarbon compound, which increases the amount of gas produced, decreases.

If it exceeds 150 kg/crrf, the hydrogenation reaction will proceed more easily than the reforming reaction, and the yield of polynuclear aromatic hydrocarbon compounds will decrease. Further, the holding time is desirably about 3 to 80 minutes; if it is less than 3 minutes, the reforming is not sufficient, and if it exceeds 80 minutes, it is disadvantageous in terms of energy consumption.

The liquid product that has passed through the high temperature holding step 30 is sent to a normal pressure distillation column or a vacuum distillation column and is separated into light oil 26 and heavy oil 30.

Currently, naphthalene has a wide range of uses as a raw material for phthalic anhydride, β-naphthol, dyes, medicines, insect repellents, surfactants, synthetic tannins, and the like, and is currently in short supply.

Tetralin and decalin, which are hydrides of naphthalene, are used only as solvents.

Therefore, it is desirable to obtain a naphthalene raw material that has a wide range of uses while avoiding contamination with hydrides as much as possible. However, as shown in the examples below, adding the high temperature holding step according to the present invention will improve the naphthalene raw material. It is extremely effective as a selective synthesis method.

That is, as mentioned above, the boiling points of tetralino and naphthalene are 207°C and 1217°C, respectively, and it is difficult to separate them by distillation. However, by going through the high temperature holding step according to the present invention, not only naphthalene hydrides but also hydrides such as anthrace/carbazole are dehydrogenated, and during subsequent distillation using existing tar distillation equipment,
Effective distillation is possible while avoiding contamination with hydrides.

Moreover, according to the present invention, since the liquid product exiting the gas-liquid separation tower at high temperature is simply maintained at high temperature, the product separated by distillation is first reformed using the conventional reforming equipment described above. It is superior in terms of thermal efficiency and installation costs compared to the conventional case.

Examples] Further, the present invention will be explained with examples.

Table S1 shows the results of elemental analysis of heavy oil obtained by removing the fraction with a boiling point of 270°C or lower from coal tar.

This heavy oil is hydrocracked using a hydrocracker 6 having a capacity of 0.5 kg/Hr, and after recovering gaseous products and raw hydrogen, it is kept at 450°C for 30 minutes. Table 2 shows the oil yield and naphthalene production rate as an example, and the results when the temperature is not maintained as a comparative example. The operating conditions are as follows.

(Hydrogen decomposition conditions) Reaction temperature: 470℃ For reaction 1: IHr Hydrogen pressure: 150kg/cm’ Catalyst (red mud) usage: 6.6% based on raw material heavy oil (High temperature holding temperature) Hoshina temperature: 450°C Retention time: 30 flin.

Holding pressure 2ioOkg/cm’ (E) The values in the table are percentages (based on raw materials).

As shown in Table 2, it was found that the light oil yield was slightly higher in the example when the temperature was maintained than in the comparative example, the naphthalene yield was significantly higher, and the telarine yield was significantly lower. did.

[Effects of the Invention] As described above, the present invention provides a high temperature holding step between the hydrocracking and distillation steps when processing coal-based heavy oil, and therefore has the following effects. .

a) It is possible to selectively synthesize polynuclear aromatic compounds.

(Chemical raw materials with little hydride contamination can be separated by distillation.

■ Excellent thermal efficiency.

■ Equipment costs are low.

・The yield of light oil increases.

[Brief explanation of drawings]

Figure 1 is a process diagram of the conventional method, Figure 2 is a process diagram of the present invention method,
FIG. 3 is a correlation diagram between the reaction temperature in hydrocracking, the light oil yield, and the amount of hydrogen residue absorbed. Patent applicant: Sumitomo Metal Industries, Ltd. Figure 1, Figure 3, length and wetness (0C) Procedural amendment (voluntary) Commissioner of the Patent Office Kazuo Wakasugi 2, Title of the invention: Processing of coal-based heavy oil Method 3: Relationship with the case of the person making the amendment Patent applicant address and name (2+1) Sumitomo Metal Industries, Ltd. 4, agent 〒
136 Address: 42-14, 1-1 Kameido, Koto-ku, Tokyo, 505-505, Happy Heights New Kameido 7, Specification subject to amendment, Column 8 for detailed explanation of the invention of suno, Contents of amendment (1) Specification, No. 2 Page - 5th line: "Hydrogenolysis" is corrected to "hydrocracking." (2) Same, page 4, line 3: "Thermal efficiency" is corrected to "thermal efficiency." (3) Same, page 6, line 6: Correct the phrase ``Light oil is also high'' to ``High quality oil yield''. (4) Same, page 1.0, line 3: [(hydrogen decomposition conditions)” should be replaced with “(hydrogenation fraction)
conditions)”. that's all

Claims (1)

[Claims] (1) After hydrocracking coal-based heavy oil using a catalyst and separating the gaseous products, the liquid product is maintained at a high temperature for a period of time to promote the reforming reaction of the liquid product. A method for processing coal-based heavy oil, which is characterized by: