JP2005330305A - Method for adsorptive desulfurization of hydrocarbon oil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for adsorptive desulfurization of a hydrocarbon oil containing disulfides as a sulfur compound, especially a method by which sufficient desulfurization can be carried out in a liquid-phase state as it is at about room temperature. <P>SOLUTION: The method for the adsorptive desulfurization of the hydrocarbon oil is characterized as bringing the hydrocarbon oil containing the disulfides as a principal component of the sulfur compound in a liquid-phase state into contact with an adsorbent containing a copper component. Conditions for bringing the hydrocarbon oil into contact with the adsorbent are preferably 10-150°C temperature, ≤3 m/h linear velocity and ≥5 min residence time. The adsorbent is preferably an adsorbent in which copper oxide is supported on an alumina carrier. The hydrocarbon oil before the desulfurization has ≤30 ppm sulfur content and 0.5-3 mass% diene concentration. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for desulfurizing a hydrocarbon oil containing a specific sulfur compound with an adsorbent.

Dealing with environmental problems is a major issue in the 21st century automobile and its fuel, and it is a fuel oil from the viewpoint of both CO ₂ emission reduction, which is a global warming gas, and so-called automobile emission reduction such as NOx. There is an increasing demand for reducing the sulfur content of hydrocarbon oils.

  Conventionally, the hydrodesulfurization method, which is a hydrocarbon oil desulfurization technique that has been mainly used, is used as it is, and removing sulfur compounds remaining in the fuel oil is a high-temperature, high-pressure reaction, and thus energy consumption is large. In addition, the enormous cost increases due to the enormous amount of catalyst and the amount of hydrogen consumed. In particular, in the case of a low-temperature liquid hydrocarbon such as LPG (liquefied petroleum gas), it is necessary to cool it again after being heated to a high temperature and desulfurized, and the energy consumption is also large.

  For example, LPG is transported through pipes in a liquid state in refineries. However, as the desulfurization method, a method of once vaporizing, hydrodesulfurizing in the gas phase, and then liquefying again has been taken, and a large amount of energy is required for vaporization and liquefaction. In particular, LPG stored as a liquid by cooling near normal pressure has been a problem of enormous energy loss in its desulfurization.

  As a desulfurization method with low energy consumption, a desulfurization method by adsorption is known. Since this method performs desulfurization under mild conditions that do not use hydrogen, it has the advantages of simple equipment, low operating costs, and low energy consumption. Although an LPG desulfurization method using an adsorbent is also known, it is generally necessary to heat to a temperature of 100 ° C. or higher, and in order to process LPG with a high vapor pressure, equipment that can withstand extremely high pressure is required. It was. In addition, a vapor phase desulfurization method using an LPG adsorbent near room temperature is known, but once vaporized and deliquefied again after desulfurization, a large amount of energy was required.

On the other hand, a special hydrocarbon oil in which the main component of the sulfur compound is a disulfide is obtained from the hydrocarbon oil depending on the raw material and the production process.
The present inventors have developed a method for adsorbing the sulfur content of hydrocarbon oil in a liquid phase (Patent Documents 1 to 3), but these methods are special in that the main component of the sulfur compound is a disulfide. It is not intended for desulfurization of any hydrocarbon oil.

Japanese Patent No. 3324746 JP 2001-123188 A Japanese Patent Laid-Open No. 2001-205004

  In general, in the desulfurization method by adsorption, energy consumption can be reduced, but the adsorption and removal may not be performed depending on the type of sulfur compound contained. Conventionally, there has not been proposed a method for adsorptive desulfurization of hydrocarbon oils containing disulfides as a sulfur compound, particularly a method capable of sufficient desulfurization while remaining in a liquid phase near room temperature. The present invention solves such problems.

  As a result of diligent research to solve the above problems, the present inventors have found that an adsorbent containing a copper component has high activity at a relatively low temperature, and a hydrocarbon oil containing disulfides as a main component of a sulfur compound. The inventors have conceived that desulfurization can be efficiently carried out even in a liquid phase state by contacting with an adsorbent containing a copper component.

  That is, the hydrocarbon oil adsorptive desulfurization method according to the present invention is characterized in that a hydrocarbon oil containing disulfides as a main component of a sulfur compound is brought into contact with an adsorbent containing a copper component in a liquid phase. The conditions for bringing the hydrocarbon oil into contact with the adsorbent are preferably a temperature of 10 ° C. to 150 ° C., a linear velocity of 3 m / hour or less, and a residence time of 5 minutes or more. The adsorbent is preferably an adsorbent in which copper oxide is supported on an alumina carrier. Further, the sulfur content of the hydrocarbon oil before desulfurization is preferably 30 ppm or less and the diene concentration is 0.5 to 3% by mass.

  In the present invention, it is possible to efficiently perform adsorption desulfurization by bringing a sulfur compound of disulfides contained in a hydrocarbon oil in a liquid phase near room temperature into contact with a specific adsorbent. For this reason, since hydrocarbon oil is not heated and pressurized and hydrogen is not consumed, hydrocarbon oil can be desulfurized by a method that consumes less energy and reduces the burden on the environment.

The hydrocarbon oil to which the present invention can be suitably applied is a fraction of kerosene, naphtha, gasoline, and LPG, and mainly contains a hydrocarbon having 3 to 16 carbon atoms. Usually, petroleum-derived hydrocarbon oil is the target. The kerosene fraction is mainly composed of hydrocarbons having about 12 to 16 carbon atoms, has a density (15 ° C.) of 0.79 to 0.85 g / cm ³ , a boiling point range of about 150 to 320 ° C., and is rich in paraffinic hydrocarbons. The gasoline fraction is mainly composed of hydrocarbons having about 4 to 11 carbon atoms, has a density (15 ° C.) of 0.783 g / cm ³ or less, and a boiling range of about 30 to 220 ° C. For use in automobiles and other similar gasoline engines, a fraction having a high octane number may be obtained by catalytic cracking, catalytic reforming, alkylation or the like. LPG is a fuel gas and industrial raw material gas mainly composed of propane, propylene, butane, butylene, butadiene and the like. Usually, it is stored in a liquid phase in a spherical tank under pressure, or is stored at a low temperature in a liquid phase in a state close to atmospheric pressure.

  The hydrocarbon oil that is the subject of the adsorptive desulfurization method of the present invention contains disulfides as the main component of the sulfur compound, and 50% or more, particularly 80% or more of the sulfur concentration contained in the hydrocarbon oil is disulfides. It is preferable that Disulfides are sulfur-containing organic compounds having disulfide bonds, such as dimethyl disulfide, methyl ethyl disulfide, methyl propyl disulfide, diethyl disulfide, methyl butyl disulfide, ethyl propyl disulfide, methyl pentyl disulfide, ethyl butyl disulfide, dipropyl disulfide, methyl. Examples thereof include chain disulfides such as hexyl disulfide, ethylpentyl disulfide, propylbutyl disulfide, methylheptyl disulfide, ethylhexyl disulfide, propylpentyl disulfide, dibutyl disulfide, and derivatives thereof.

  In addition, the sulfur concentration of the hydrocarbon oil that is the target of the adsorptive desulfurization method of the present invention is not particularly limited, but the lower the sulfur concentration of the hydrocarbon oil, the longer the life of the adsorbent. The economics of the desulfurization method can be improved. For example, the hydrocarbon oil whose sulfur concentration is 0.05-500 ppm, Preferably it is 0.05-30 ppm can be mentioned.

The adsorbent used in the present invention contains a copper component, and the copper component is preferably contained in an amount of 0.1 to 15% by mass, particularly 1 to 10% by mass as the copper element weight with respect to the adsorbent weight. The element weight of the transition metal contained in the adsorbent is preferably 70% by mass or more, particularly preferably 95% by mass or more, and more preferably copper is supported on the porous carrier. In order to prevent segregation of copper on the outer surface of the adsorbent particles, the weight of the copper component per unit specific surface area is preferably 0.7 mg / m ² or less, particularly 0.5 mg / m ² or less. In order to increase the adsorption capacity of disulfides, it is preferable that the copper component is large, and it is particularly preferable that the weight of the copper component per unit specific surface area is 0.3 to 0.7 mg / m ² . Moreover, it is also possible to carry | support further components other than copper as needed. Zinc and iron can be supported as a component other than copper, but the amount less supported other than copper is, for example, 0.1 mg / m ² or less, particularly 0. It is preferably 02 mg / m ² or less.

The specific surface area of the adsorbent is preferably 150 m ² / g or more, particularly 200 m ² / g or more. In more contacting conditions at low temperatures, sulfur compounds physically adsorbed on the adsorbent surface, then gradually it believed to change the chemical adsorption state, a specific surface area of a physical adsorption in the initial decreases less than 200 meters 2 / ^g As a result, an adsorbent region in which the sulfur concentration decreases, called an adsorption zone, is enlarged. That is, a longer residence time is required. Therefore, the specific surface area of the adsorbent is preferably 200 m ² / g or more, and particularly preferably 250 m ² / g or more. In order to obtain mechanical strength, the macropore volume, which is the volume of pores having a pore diameter of 0.1 μm or more, is preferably 0.2 ml / g or less, particularly preferably 0.15 ml / g or less. In general, the specific surface area and the total pore volume are measured by a nitrogen adsorption method, and the macropore volume is measured by a mercury intrusion method. The nitrogen adsorption method is simple and commonly used, and is described in various documents. For example, Kazuhiro Hagio: Shimazu review, 48 (1), 35-49 (1991), ASTM (American Society for Testing and Materials) Standard Test Method D 4365-95.

  The adsorbent used in the present invention is preferably one in which copper is supported on an inorganic porous carrier such as alumina or activated carbon, and particularly preferably one in which copper is supported on an alumina carrier. The crystallinity and type of alumina constituting the porous carrier are not limited. However, in the case of γ-alumina generally used as a catalyst carrier, it is difficult to produce a carrier having a large specific surface area and pore volume and high fracture strength. An amorphous alumina carrier such as activated alumina is preferably used because of its low wear rate and low powder production.

  The alumina carrier is a porous particle mainly composed of alumina, and is usually preferably a spherical particle having a diameter of 0.5 to 5 mm, particularly 1 to 3 mm. The spherical shape is advantageous in terms of diffusion in the pores of the adsorbed sulfur compound because the average distance from the outer surface to the adsorbent center is short and the average concentration gradient can be increased as compared with a cylinder type (columnar shape) or the like. It is preferable that the breaking strength is 3.0 kg / pellet or more, particularly 3.5 kg / pellet or more because cracking of the adsorbent does not occur. Usually, the breaking strength is measured by a compressive strength measuring device such as a Kiya-type tablet breaking strength measuring device (Toyama Sangyo Co., Ltd.).

  The adsorbent in which copper is supported in the pores of the alumina support has a green color due to the interaction between copper and alumina. When the concentration of copper is too high with respect to the specific surface area, black copper oxide is obtained without any interaction with alumina. Since this black copper oxide is easily detached, it must be detached during use and mixed into the hydrocarbon oil, so that it is necessary to prevent black copper oxide from being formed. Therefore, it is preferable that the supported copper exhibits a green color, and the use of an adsorbent exhibiting a black color is not preferable. Specifically, the proportion of black particles contained in the adsorbent is preferably 10% or less, particularly 5% or less. The adsorbent is produced, for example, by the method shown in Japanese Patent No. 3324746.

  The conditions for bringing the hydrocarbon oil into contact with the adsorbent containing a copper component are a temperature of 10 to 150 ° C., preferably 20 to 90 ° C., more preferably 60 to 90 ° C. If the temperature is lower than 10 ° C, sufficient adsorption performance cannot be obtained. On the other hand, if the temperature is higher than 150 ° C, it is not preferable from the viewpoint of pressure resistance of the equipment and energy saving. Further, since it does not involve a reaction at a high temperature, it can be desulfurized even if it contains a diene. Even in an adsorbent containing a highly active copper component, since it is adsorbed at a low temperature, the influence of diene on sulfur adsorption can be suppressed. The diene concentration can also be applied to hydrocarbon oils containing 3 wt% or less, preferably 1.5 wt% or less, and 0.5 wt% or more. Preferably, the linear velocity is 3 m / hour or less, particularly 0.3 m / hour to 3 m / hour, or the residence time is 5 minutes or more, particularly 5 minutes to 600 minutes, more preferably 15 minutes to 600 minutes. Adsorption performance is obtained.

  Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto.

Example 1
NK-311 manufactured by Advanced Refining Technologies Co., Ltd. was used as the copper oxide-carrying adsorbent. This is one in which copper oxide is supported on a spherical alumina carrier having a diameter of 2 mm, the supported amount is 7.6% by mass as the weight of copper element, and the specific surface area is 264 mg / m ² . The copper oxide-supported adsorbent was dried at 150 ° C. for 3 hours, and then packed into a 300 mm long column with a volume of 24 mL. The model oil in the liquid phase was circulated at (residence time: 6 minutes). As the model oil, normal decane blended with dimethyl disulfide so as to have a sulfur concentration of 20 ppm was used.

  The change in the sulfur concentration at the column outlet after the start of flow is shown in FIG. From this figure, the sulfur concentration at the outlet draws a curve that rises rapidly at the beginning of distribution and then gradually increases.

Comparative Example 1

The sample was distributed under the same conditions as in Example 1 except that alumina was used instead of the copper oxide-supporting adsorbent. The alumina used was a spherical activated alumina having a diameter of 2 mm, a purity of 99%, and a specific surface area of 350 mg / m ² .

  In this case, the sulfur concentration at the column outlet is a curve that rises rapidly at the beginning of the flow, and then gradually increases, as in FIG. However, from the comparison result of the removal amount (Table 1) when the ratio of the effluent amount to the adsorbent volume = 100, it can be seen that the sulfur compound adsorption performance of Example 1 is excellent.

Examples 2-4
As Examples 2 to 4, the model oil was circulated through the column in the same manner as in Example 1 except that the temperature when the model oil was circulated through the column and the sulfur concentration of the model oil were changed. The amount of removal was defined as the difference between the value at which the concentration at the column outlet becomes almost constant after the start of circulation and the sulfur concentration in the model oil. The removal amount was compared with the removal amount (Table 2) when the ratio of the effluent amount to the adsorbent volume = 100. Table 2 shows the temperature when flowing through the column and the sulfur concentration of the model oil. In this temperature range, the model oil circulated in the liquid phase.

  From Examples 1 to 3, the removal amount increases as the adsorption temperature increases. From Examples 1 and 4, the removal amount increases as the sulfur concentration of the model oil increases.

Example 5
In Example 5, the column length was increased to 2100 mm, the internal volume was 189 mL, the residence time was 43 minutes, and the sulfur concentration of the model oil was 300 ppm. Otherwise, the test was performed under the same conditions as in Example 1. I did it. As a result, as shown in FIG. 2, desulfurization was possible until the outlet sulfur concentration was less than 1 ppm while the effluent amount / adsorbent amount was about 6. From this example, it can be seen that the sulfur concentration can be desulfurized to less than 1 ppm if a sufficient residence time is secured with respect to the raw material sulfur concentration.

Example 6
As the model oil, the model oil was circulated in the same manner as in Example 1 except that normal decane and 3% by mass of 1,3-normal pentadiene and dimethyl disulfide were blended so that the sulfur concentration was 2000 ppm. did. As a result, there was no significant difference between the outlet concentration (sulfur concentration at the column outlet) / inlet concentration (sulfur concentration of the model oil) of both when the flow rate / the adsorbent amount = 60 after the flow started. From this example, it was found that even if a diene compound is contained in the hydrocarbon oil, the adsorptive desulfurization treatment of the present invention is not affected.

  Hydrocarbon oil can be desulfurized by a method that consumes less energy and reduces the environmental burden of sulfur compounds of disulfides contained in hydrocarbon oils such as kerosene, naphtha, gasoline, and LPG.

It is a figure which shows the change of the sulfur density | concentration of the column exit with respect to the flow volume to the column by Example 1. FIG. The horizontal axis indicates the ratio of the effluent volume to the adsorbent volume, and the vertical axis indicates the ratio of the column outlet sulfur concentration to the column inlet sulfur concentration (percent (%)). FIG. 10 is a graph showing a change in the sulfur concentration at the column outlet with respect to the amount of liquid flowing through the column according to Example 5. The horizontal axis indicates the ratio of the effluent volume to the adsorbent volume, and the vertical axis indicates the ratio of the column outlet sulfur concentration to the column inlet sulfur concentration (percent (%)).

Claims (4)

  A hydrocarbon oil adsorptive desulfurization method comprising contacting a hydrocarbon oil containing a disulfide as a main component of a sulfur compound with an adsorbent containing a copper component in a liquid phase.   2. The method for adsorptive desulfurization of hydrocarbon oil according to claim 1, wherein the conditions for bringing the hydrocarbon oil into contact with the adsorbent are a temperature of 10 ° C. to 150 ° C., a linear velocity of 3 m / hour or less, and a residence time of 5 minutes or more. .   The method for adsorptive desulfurization of hydrocarbon oil according to claim 1 or 2, wherein the adsorbent is an adsorbent in which copper oxide is supported on an alumina carrier.   The adsorptive desulfurization method for hydrocarbon oil according to any one of claims 1 to 3, wherein the sulfur content of the hydrocarbon oil before desulfurization is 30 ppm or less and the diene concentration is 0.5 to 3 mass%.