JP2002080859A - Hydrogenation method for coal liquid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydrogenation method for coal liquid whereby the smoke point and cetane number of a liquefied oil-kerosene-gas oil fraction can be improved under mild reaction conditions in a high yield. SOLUTION: In this method, hydrogenation is carried out under a pressure of 10 MPa (G) while a part of the resultant hydrogenated oil is being recycled. In another embodiment, the first step is conducted under the above conditions and is followed by the second step.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for hydrotreating coal liquefied oil, and more particularly to a method for hydrotreating coal liquefied oil.

[0002]

2. Description of the Related Art As a measure against depletion of petroleum resources, a method of obtaining a coal liquefied oil by adding a catalyst to coal and heating it together with hydrogen has been studied for many years, and many reports have been made. However, coal liquefied oil is derived from the properties of coal, and has a higher content of hetero compounds such as nitrogen and aroma compounds than petroleum, and does not conform to current petroleum product standards. Therefore, there is a need for a technology for refining a coal liquefied oil, conforming it to a standard, and converting it to one that can be used in the market.

For example, when producing kerosene or light oil products,
In a single-stage hydrotreating method using a hydrogenation catalyst such as cobalt-molybdenum or nickel-molybdenum used in petroleum refining, it is difficult to remove a high content of a hetero compound, particularly nitrogen, and to remove an aroma compound. In this case also, the degree of hydrogenation of the nucleus does not increase the amount of linear chain saturation due to ring opening. Therefore, when the reaction conditions are made severe and the temperature and pressure are increased, some improvement can be seen, but the catalyst is greatly deteriorated and the catalyst life is shortened.
In addition, the equipment becomes expensive, which is economically disadvantageous.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above, and has an object to improve the smoke point and the cetane number of a liquefied oil and gas oil fraction under mild reaction conditions and to obtain a high yield. It is an object of the present invention to provide a method for hydrotreating coal liquefied oil which can be carried out.

[0005]

Means for Solving the Problems As a result of earnest studies, the present inventors have found that the object of the present invention can be effectively achieved by recycling a part of the hydrotreated oil.
The present invention has been completed based on the findings.

That is, the gist of the present invention is as follows. 1. A method for hydrotreating coal liquefied oil, characterized in that the reaction pressure is 10 MPa (G) or less and a part of the hydrotreated oil is recycled. 2. 2. The method for hydrotreating coal liquefied oil according to the above 1, wherein the recycling ratio is 0.3 or more. 3. A method for hydrotreating coal liquefied oil, comprising performing a first-stage hydrotreatment under the above-mentioned conditions and then a second-stage hydrotreatment.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the present invention, as a coal liquefied oil, a catalyst is added to coal such as bituminous coal and lignite, and the oil liquefied by heating with hydrogen is distilled to obtain a boiling point of 170 to 4
Kerosene oil fractions in the range of 00 ° C. are preferably used. The properties of the coal liquefied oil preferably used as the feedstock oil have a cetane number of 10 to 18, a smoke point of 5 to 10 mm, and a composition having a saturated content of 20 to 30 volume% and an aroma content of 70 to 80.
% By volume, nitrogen content of 2,000 to 8,000 ppm, sulfur content of 100 to 1,000 ppm, oxygen content of 0.5 to 2.
5% by mass.

The features of the hydrotreating of the first invention of the present application are that the reaction pressure is reduced to 10 MPa (G) or less and a part of the hydrotreated oil is recycled. When the reaction pressure exceeds 10 MPa (G), complete hydrogenation occurs, and a cracking reaction easily occurs in a second-stage reaction described later, which lowers the yield of a kerosene oil fraction and shortens the catalyst life. It is not preferable. It is preferably in the range of 5 to 8 MPa (G).

It is essential to recycle a part of the hydrotreated oil, but if it is not recycled, the degree of improvement in the cetane number will be small. Also, the denitrification rate decreases. In that case, the recycle ratio [recycle amount / total feed amount (volume ratio)] is preferably 0.3 or more. More preferably, it is 0.3 to 0.7.

[0010] The reaction type of the hydrotreating of the present invention can be selected from various processes such as a fixed bed, a moving bed, a boiling bed and a suspension bed, but a fixed bed is usually employed. For other conditions, in the case of a fixed bed, the reaction temperature is usually 33
0 to 450 ° C (preferably 340 to 400 ° C), and a liquid hourly space velocity (LHSV) of 0.1 to 5 hr ^-1 (preferably 0.1 to 5 hr ^-1 ).
3-1 hr ^-1 ), and the hydrogen / oil ratio is 500-2,500.
Nm ³ / kl (preferably 700~2,000Nm ³ /
kl).

As the catalyst for the hydrotreating of the present invention, an alumina carrier having Ni-Mo and Ni-W supported thereon is usually used. In the above-mentioned hydrogenation treatment, a de-hetero reaction occurs mainly, and nitrogen content, sulfur content, and oxygen content are reduced, and cetane number is improved.

Next, the hydrogenation treatment of the second invention of the present application will be described. The present invention is a method for hydrotreating coal liquefied oil, which comprises performing a first-stage hydrotreatment under the above-mentioned conditions and then performing a second-stage hydrotreatment.

The hydrotreated oil from the first stage is separated into gas and reaction water by a stripper or the like, and is subjected to a second stage hydrotreatment. The type of reaction for the second-stage hydrotreatment can be selected from various processes such as a fixed bed, a moving bed, a boiling bed, and a suspended bed, but a fixed bed is usually employed.

Regarding the reaction conditions in the case of the fixed bed,
Usually, the reaction temperature is from 250 to 350 ° C (preferably 270 ° C).
~ 300 ° C), reaction pressure 10MPa (G) (preferably 5 ~ 8MPa (G), liquid hourly space velocity (LHSV) 0.1
５5 hr ^-1 (preferably 0.3-1 hr ^-1 ), and the hydrogen / oil ratio is 500-2,500 Nm ³ / kl (preferably 700-2,000 Nm ³ / kl).

[0015] As a catalyst for the second stage hydrotreating, Pt, Pt-Pd, Ni
Those carrying -W are used. In that case, as the zeolite, X type, Y type, faujasite, ZSM-
5, various types such as mordenite can be used.

In the second stage of the hydrogenation treatment,
The ring-opening reaction occurs mainly, and the cetane number and smoke point are improved. According to the present invention, coal liquefied oil can be upgraded to have a smoke point of 21 mm or more and a cetane number of 45 or more, and the composition has a saturated content of 90 to 95% by volume and an aroma content of 0 to 5 volumes. %, The nitrogen content can be 0 to 10 ppm, the sulfur content can be 0 to 10 ppm, and the oxygen content can be 0 to 0.2 mass%, and the product conforms to petroleum product standards.

[0017]

Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. [Example 1] Coal liquefied oil shown in Table 1 was used as a raw material oil, and a catalyst in which Ni and W were supported on an alumina carrier was used as a catalyst. The reaction pressure was 5 MPa (G), the reaction temperature was 350 ° C,
LHSV; 0.5 hr ^-1 , hydrogen / oil ratio; 1,000
Hydrotreating was performed using a microreactor with a recycling line under the conditions of Nm ³ / kl and a recycling ratio of 0.5. Table 2 shows the properties of the produced oil.

Example 2 A hydrogenation treatment was performed in the same manner as in Example 1, except that the recycle ratio was changed to 0.7. Table 2 shows the properties of the produced oil.

Comparative Example 1 A hydrogenation treatment was performed in the same manner as in Example 1 except that recycling was not performed. Table 2 shows the properties of the produced oil.

[0020]

[Table 1]

[0021]

[Table 2]

Example 3 A coal liquefied oil shown in Table 1 was used as a raw material oil, and a catalyst in which Ni and W were supported on an alumina carrier was used as a catalyst, at a reaction pressure of 7.5 MPa (G), a reaction temperature; 360 ° C., LHSV; 0.67 hr ⁻¹ , hydrogen / oil ratio; 1,000 Nm ³ / kl, recycling ratio;
Under a condition of 0.5, a hydrogenation treatment was performed using a microreactor with a recycling line. 3rd property of generated oil
Shown in the table.

Comparative Example 2 A hydrogenation treatment was carried out in the same manner as in Example 3, except that recycling was not performed. Table 3 shows the properties of the produced oil.

Comparative Example 3 In Example 3, the LHSV
Was set to 0.5, the reaction pressure was set to 15 MPa (G), and the hydrogenation treatment was performed in the same manner except that recycling was not performed. Table 3 shows the properties of the produced oil.

[0025]

[Table 3]

Example 4 The oil produced in Example 3 was used as a raw material oil, and an alumina-zeolite carrier having Pt and Pd supported thereon was used as a catalyst. The reaction pressure was 5 MPa (G).
Reaction temperature: 288 ° C., LHSV: 0.5 hr ⁻¹ , hydrogen /
Hydrotreating was performed using a microreactor under the conditions of an oil ratio of 1,000 Nm ³ / kl. The resulting oil was distilled to obtain a fraction having a boiling point of 170 to 350 ° C. Table 4 shows the yield and properties of the fraction. The yield of the fraction is
The first stage raw material oil was determined as 100.

Example 5 The oil produced in Example 3 was used as a feed oil, and a catalyst in which Pt and Pd were supported on an alumina-zeolite carrier was used as a catalyst. The reaction pressure was 7.5 MPa.
(G), reaction temperature: 305 ° C., LHSV: 0.5 h
Hydrotreating was performed using a microreactor under the conditions of r ⁻¹ , hydrogen / oil ratio; 1,000 Nm ³ / kl.
The resulting oil was distilled to obtain a fraction having a boiling point of 170 to 350 ° C.
Table 4 shows the yield and properties of the fraction.

[Comparative Example 4] The oil produced in Comparative Example 3 was used as a raw material oil, Pt and Pd supported on an alumina-zeolite carrier were used as a catalyst, and the reaction pressure was 5 MPa (G).
Reaction temperature: 300 ° C., LHSV: 0.5 hr ⁻¹ , hydrogen /
Hydrotreatment was performed using a microreactor under the conditions of an oil ratio of 1,000 Nm ³ / kl. The resulting oil was distilled to obtain a fraction having a boiling point of 170 to 350 ° C. Table 4 shows the yield and properties of the fraction.

[0029]

[Table 4]

The following can be seen from the examples and comparative examples. The cetane number of the produced oil can be improved by partially recycling the hydrotreated oil from Examples 1 and 2. The cetane number, smoke point, and yield can be improved as compared with the fourth and fifth embodiments. In Comparative Example 4, the feed oil was completely hydrogenated in the first stage, and was easily decomposed in the second stage, and the yield was reduced.

[0031]

According to the present invention, there is provided a method for hydrotreating coal liquefied oil which can improve the smoke point and cetane number of a liquefied petroleum gas oil fraction under mild reaction conditions and can obtain a high yield. Can be provided.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshio Akai 1280 Kamiizumi, Sodegaura-shi, Chiba F-term (reference) 4H029 CA00 DA00 DA09 DA11

Claims (3)

[Claims] 1. A method for hydrotreating coal liquefied oil, comprising:
A method for hydrotreating coal liquefied oil, characterized in that the reaction pressure is 10 MPa (G) or less and a part of the hydrotreated oil is recycled. 2. The method for hydrotreating coal liquefied oil according to claim 1, wherein the recycling ratio is 0.3 or more. 3. A method for hydrotreating coal liquefied oil, comprising performing a first-stage hydrotreatment under the above-mentioned conditions, and further performing a second-stage hydrotreatment.