JP2000192054A - Method for decolorizing gas oil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remove coloring substances at a high efficiency from a colored gas oil component and to thereby obtain a good-hue low-sulfur gas oil at a low cost by bringing a colored gas oil component desulfurized to a specified sulfur content or lower by a hydrodesulfurization process into contact with activated coal having a specified mean pore diameter. SOLUTION: A gas oil component, such as straight-run gas oil, catalytically cracked oil, thermally cracked gas oil, or vacuum-distilled gas oil, deeply desulfurized to a sulfur content of 0.05 mass % or below by a hydrodesulfurization process and having a boiling range of 150-450 deg.C is brought into contact with activated coal having a mean pore diameter of 100-11,000 Å. The conditions for the contact desirably include a hydrogen pressure of 0.1-4.9 MPa, a temperature of 0-400 deg.C, and a liquid hourly space velocity of 0-20 /h. The activated coal used is exemplified by one made by using wood, waste plastics, coal, petroleum heavy oil, or petroleum- or coal-derived pitch as a starting material and is desirably one containing 10 mass % or below inorganic component impurities. It is desirably a formed one in a columnar, four-leaf, spherical, or like form.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decolorizing gas oil, and more particularly, to a method for removing coloring substances generated by desulfurizing a gas oil fraction.

[0002]

BACKGROUND ART Each oil fraction obtained by distillation or cracking of crude oil generally contains sulfur compounds, and when these oils are used as fuel, air pollutants such as sulfur oxides caused by the sulfur compounds. Is released into the atmosphere. In recent years, air pollution by exhaust gas (NOx and particulate matter) from diesel engines has become serious, and as a countermeasure from the viewpoint of fuel, there is a strong demand for reduction of sulfur content in light oil. In fact, in response to emission regulations for NOx and particulate matter in diesel exhaust gas,
The regulation value of sulfur in light oil was revised to 0.05% by mass in October. In Europe, the sulfur content in light oil was reduced to 350 ppm (0.035% by mass), 200% by 2000.
It has been proposed that the concentration be increased to 50 ppm by mass (0.005% by mass) by five years.

[0003] Under such circumstances, the development of an ultra-deep desulfurization technique for greatly removing the sulfur content in light oil has been gaining importance. Techniques for reducing the sulfur content in gas oil include harsh operating conditions for hydrodesulfurization, for example, lowering the liquid hourly space velocity and increasing the reaction temperature. However, when the liquid hourly space velocity is reduced, although the desulfurization ability is improved, the purification processing capacity is reduced. Therefore, in order to obtain a predetermined processing capacity, it is necessary to greatly expand the scale of the equipment. On the other hand, when the reaction temperature is increased, ultra-deep desulfurization of light oil can be performed without capital investment, but there is a problem that the light oil is colored and has a yellow-green fluorescent color. In the Japanese market, since there is a strict requirement for the hue of the product gas oil (Toru Takatsuka, Yukitaka Wada, Catalyst vol. 33, p306 (1991)), it is urgently necessary to solve this coloring problem.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for efficiently removing colored substances in desulfurized gas oil in consideration of the above points.

[0005]

SUMMARY OF THE INVENTION The inventors of the present invention have been studying to achieve the above object and have noticed that colored substances in light oil can be adsorbed and removed with activated carbon (JP-A-6-136370). As a result of further study on the adsorptive removal effect by the method, the following findings were obtained.

In the case of a catalyst or activated carbon, in general, the larger the surface area or pore volume, the larger the contact area. Therefore, the activity of the catalyst or activated carbon is high, and the larger the pore diameter, the smaller the surface area or pore volume. Therefore, it is considered that the activity of the catalyst and the activated carbon is low. Therefore, the present inventors first,
When the correlation between the surface area and pore volume of activated carbon and the ability to remove colored substances in desulfurized gas oil was examined, contrary to the above-mentioned common sense, even if the surface area was increased, the effect of removing colored substances was not enhanced, and activated carbon was not increased. However, even if the pore volume of was increased, the effect of removing the coloring substance did not increase. Next, the present inventors examined the correlation between the pore diameter to reduce or increase the surface area and pore volume, and the ability to remove the coloring substance in the desulfurized gas oil, surprisingly, the larger the pore diameter, The adsorption ability of the coloring substance was improved, and the removal ability was improved. However, if the pore diameter is too large, it is considered that even high-molecular-weight hydrocarbons other than the coloring substance will be adsorbed, so that a desired treatment capacity cannot be obtained. Therefore, it has been concluded that when using activated carbon as a remover for the coloring substance, it is necessary to obtain optimum physical properties (especially pore diameter).

The present invention has been made on the basis of the above-mentioned findings. Activated carbon having an average pore diameter of 100 to 11,000 ° in a pore distribution measured by a mercury intrusion method is provided with a sulfur content of 0 to 1100 ° by a hydrodesulfurization method. A gist of the present invention is a method of bringing a colored light oil component into contact by adjusting the content to 0.05% by mass or less to adsorb and remove the colored substance. The contact condition at this time is a hydrogen pressure of 0.1 to
4.9 Mpa, temperature 0-400 ° C, liquid space velocity 0-20
hr- ¹ is preferable.

The target oil (feed oil) of the present invention is a light oil having a sulfur content of 0.05% by mass or less, for example, a straight run gas oil, a catalytic cracking gas oil, a pyrolysis gas oil, a vacuum distillation gas oil (VG).
A gas oil fraction obtained by deep desulfurization of O) or the like is suitable. Typical examples of properties other than the sulfur content of these feedstocks include a boiling point range of 150 to 450 ° C.

Activated carbon, which is the adsorbent of the present invention, includes plant-based wood, sawdust, coconut shell, pulp waste liquor, plastic waste, fossil fuel-based coal, petroleum heavy oil, and petroleum obtained by thermally decomposing them. Activated carbon using coal-based pitch or the like as a starting material, and various other activated carbons can be used.

The impurities in the activated carbon include ash, that is, inorganic components such as Al ₂ O ₃ , Fe ₂ O ₃ , CaO, and Mg.
O, NaO, SiO _{2 and the} like can be mentioned, but it is desirable that these impurities are as small as possible.
0 mass% or less, preferably 5 mass% or less, more preferably 2 mass% or less.

The activated carbon of the present invention has an average pore diameter measured by a mercury intrusion method of 100 to 11000 °, preferably 100 to 11,000 °, regardless of the surface area and the pore volume, in order to enhance the performance of removing colored substances. 8000, more preferably 200 to 6000, or 200 to 4000, or 350 to 6000, more preferably 350 to 400
Limited to 0 °.

The shape of the activated carbon is not particularly limited, and various shapes such as a columnar shape, a four-lobe shape, a spherical shape, and a powdery shape can be adopted. It is preferable to use a molded product.

[0013] The decolorizing method of the present invention is characterized in that the hydrogen pressure is 0.1 to
4.9 Mpa, temperature 0-400 ° C, liquid space velocity 0-20
hr ^-1, preferably 0～10Hr ^-1 or 0.1
２０20 hr ⁻¹ , more preferably 0.1 to 10 hr ⁻¹
Under the conditions described above, it is desirable that the activated carbon and the light oil fraction containing the coloring substance are brought into contact with each other, but it is advantageous to use normal temperature and normal pressure in terms of cost.

To carry out the decolorization method of the present invention on a commercial scale,
A fixed bed, a moving bed, or a fluidized bed type activated carbon layer (adsorption layer) using the above-mentioned activated carbon (adsorbent) is formed in a decolorizing treatment apparatus (adsorption apparatus), and a feedstock oil is introduced into this apparatus. Examples of the method include a method of performing a decolorizing treatment under the conditions and a method of charging the above activated carbon into a light oil storage tank and performing the decolorizing treatment in the tank. In general, a fixed-bed activated carbon layer is formed in a decolorization treatment device, a feedstock oil is introduced into the upper portion of the device, the raw oil is passed through the fixed bed from top to bottom, and the generated oil flows out from the lower portion of the device. Conversely, feed oil is introduced into the lower part of the apparatus, passes through the fixed bed from bottom to top, and the generated oil flows out from the upper part of the apparatus. The method of performing the decolorization treatment by charging activated carbon into a light oil storage tank is advantageous in terms of cost because existing equipment can be used as it is and there is no need to invest in equipment.

The decolorization method of the present invention may be a single-stage decolorization treatment method in which the above activated carbon is charged into a single decolorization treatment device, or a multi-stage continuous decolorization treatment method in which the activated carbon is charged into a plurality of devices. It may be.

In the present invention, the above-mentioned activated carbon (adsorbent) may be used as it is, but before use (that is, prior to performing the decolorizing treatment method of the present invention), immediately before charging the reactor. Alternatively, or after filling, it is preferable to perform a drying treatment in the reactor to sufficiently remove the adsorbed moisture.
This drying treatment is carried out at 50 to 500 ° C., preferably 100 to 500 ° C.
Perform at 300 ° C.

Example 1 Activated carbon A (peat) having the physical properties shown in Table 1 measured by the following method was used as an adsorbent, and a straight-run gas oil having the following properties was used as a raw material oil. did.

[Method of Measuring Physical Properties of Adsorbent] Specific surface area was measured by the BET method using nitrogen adsorption. As the nitrogen adsorption device, a surface area measuring device (Bellsoap 28) manufactured by Nippon Bell Co., Ltd. was used. -The pore volume, average pore diameter, and pore distribution were measured by a mercury intrusion method. The mercury intrusion device is a porosimeter (MICROMERITICS AUTO-PORE)
9200: manufactured by Shimadzu Corporation).

[Method of decolorizing straight-run gas oil] First, the adsorbent is pulverized, sieved to a certain particle size (sieve opening is 1.4 mm to 500 μm, 12 to 30 mesh), and then charged into a normal pressure flow type reaction apparatus to be fixed bed type catalyst layer. Was formed and pretreated (dried) under the following conditions. 2. Next, the raw material oil was introduced from the lower part of the reactor, decolorized under the following conditions, and the produced oil was discharged from the upper part of the reactor. 3.3 hours later, the generated oil is collected, and its hue (Saybolt color) is measured with a color meter “O” manufactured by Nippon Denshoku Co., Ltd.
The measurement was performed using CH-300A ". The results are shown in Table 2.

[Properties of feedstock oil] Oil type; desulfurized straight-run gas oil Specific gravity (15/4 ° C); 0.8367 Distillation properties: Initial boiling point: 189.5 ° C, 50% point: 294.5 ° C, 90 % Point is 348.5 ° C., end point is 367.0 ° C. Sulfur component; 53 mass ppm nitrogen component; 8 mass ppm hydrogen component; 14 mass% kinematic viscosity (＠ 30 ° C.); 4.901 cSt Pour point; ° C Cetane index; 60.2 Saybolt color; -10

[Adsorbent pretreatment conditions] Pressure; normal pressure atmosphere; air temperature; maintained at 120 ° C. for 24 hours

[Decoloring treatment conditions] Temperature: room temperature (16 to 24 ° C.) Pressure: 0.1 MPa Liquid hourly space velocity: 5.0 hr ⁻¹ Oil passing time: 3 hours

Example 2 A decolorizing treatment was performed in the same manner as in Example 1 except that activated carbon B (lignite) having the physical properties shown in Table 1 and measured in the same manner as in Example 1 was used as the adsorbent. Was. Table 2 shows the results
Are shown together.

Example 3 A decolorizing treatment was performed in the same manner as in Example 1 except that activated carbon C (peat) having the physical properties shown in Table 1 and measured in the same manner as in Example 1 was used as the adsorbent. Was. Table 2 shows the results
Are shown together.

Example 4 A decolorizing treatment was performed in the same manner as in Example 1 except that activated carbon D (olive charcoal) having the physical properties shown in Table 1 and measured in the same manner as in Example 1 was used as the adsorbent. went. The results are shown in Table 2.

Example 5 The same procedure as in Example 1 was carried out except that activated carbon E having the physical properties shown in Table 1 (reformed from activated carbon manufactured by JGC Chemicals Co., Ltd.) was used as the adsorbent. Decolorization was performed in the same manner as in Example 1. The results are shown in Table 2.

Example 6 A decolorizing treatment was carried out in the same manner as in Example 1 except that activated carbon F (coal-based) having the physical properties shown in Table 1 and measured in the same manner as in Example 1 was used as the adsorbent. went. The results are shown in Table 2.

Example 7 A decolorizing treatment was performed in the same manner as in Example 1 except that activated carbon G (brown coal) having the physical properties shown in Table 1 and measured in the same manner as in Example 1 was used as the adsorbent. Was. Table 2 shows the results
Are shown together.

Example 8 A decolorizing treatment was performed in the same manner as in Example 1 except that activated carbon H (coal-based) having the physical properties shown in Table 1 and measured in the same manner as in Example 1 was used as the adsorbent. went. The results are shown in Table 2.

Example 9 An activated carbon I having a physical property shown in Table 1 (trade name "GL30-No. 1" manufactured by Nimura Chemical Co., Ltd.) measured by the same method as in Example 1 was used as an adsorbent. Decolorization was performed in the same manner as in Example 1. The results are shown in Table 2.

Example 10 The particle size of activated carbon A (peat) was from 500 μm to 180 μm.
The decolorizing process was performed in the same manner as in Example 1 except that m (30 to 83 mesh) was used. The results are shown in Table 2.

Comparative Example 1 HY zeolite having the physical properties shown in Table 1 measured by the same method as in Example 1 was used as the adsorbent, and the particle size was changed from 500 μm to 180 μm (30 to 83 mesh). Decolorization was performed in the same manner as in Example 1.
The results are shown in Table 2.

Comparative Example 2 As an adsorbent, activated carbon J having the physical properties shown in Table 1 (manufactured by Kanto Chemical Co., Ltd., product number 0) measured in the same manner as in Example 1
No. 1084-02, pellets) was crushed and sieved to a certain particle size, and subjected to a decolorizing treatment in the same manner as in Example 1. The results are shown in Table 2.

COMPARATIVE EXAMPLE 3 Activated carbon K (petroleum pitch) having the physical properties shown in Table 1 measured by the same method as in Example 1 was used as an adsorbent, and decolorization was performed in the same manner as in Example 1. Was. The results are shown in Table 2.

[0035]

[Table 1]

[0036]

[Table 2] Activated carbon AK: same as Table 1

Example 11 [Study by Batch Method] Using activated carbon A which had been subjected to the same pretreatment as in Example 1, the decolorizing treatment of the straight-run gas oil used in Example 1 was carried out by the batch method under the following conditions. I went in. Table 3 shows the results.

[Method for decolorizing straight-run gas oil] Temperature; normal temperature (16 to 24 ° C.) Pressure: 0.1 MPa Activated carbon A used amount: 50 g Raw material oil: 100 cc Decolorizing treatment time: 20 hours

Comparative Example 4 A decolorizing treatment was performed in the same manner as in Example 11 except that the HY zeolite used in Comparative Example 1 was used as an adsorbent.
Table 3 shows the results.

[0040]

[Table 3]

As is clear from Tables 2 and 3, according to the present invention, the ultra-deep desulfurized gas oil having a fluorescent color can be easily converted into a gas oil having a Saybolt color of 0 or more and a good hue.

[0042]

As described in detail above, according to the present invention,
It is possible to solve the problem of coloring, which is a problem in producing light oil having a low sulfur content, without significantly improving a conventionally used apparatus, and as a result, a low sulfur with good hue is obtained. Light oil can be provided at low cost.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Fujikawa 1134-2 Gongendo, Satte City, Saitama Prefecture Inside the R & D Center, Cosmo Research Institute, Inc. (72) Hiroshi Mizuguchi 1134-2 Gongendo, Satte City, Saitama Prefecture Kosmo Research Institute R & D Center (72) Inventor Kazuo Dei 1134-2 Gongendo, Satte-shi, Saitama F-term in Kosmo Research Institute R & D Center 4H029 DA06 DA09

Claims (1)

[Claims] 1. A gas oil characterized by contacting a light oil component colored by reducing the sulfur content to 0.05% by mass or less with activated carbon having an average pore diameter of 100 to 11,000 ° by a hydrodesulfurization method. Decolorization method.