JP2001279274A - Fuel oil for fuel cell, desulfurization method and method for producing hydrogen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a petroleum-based hydrocarbon easy to undergo desulfurization treatment and suitable as a raw fuel oil for fuel cells, to provide a desulfurization method for producing a fuel oil for fuel cells through desulfurization treatment of the above hydrocarbon, and to provide a method for producing hydrogen for fuel cells by using the fuel oil obtained above. SOLUTION: The raw fuel oil for fuel cells is characterized by being <=15 wt.ppm in alkyldibenzothiophene content. The hydrocarbon desulfurization method comprises subjecting the above raw fuel oil to desulfurization treatment, and the method for producing hydrogen for fuel cells comprises catalyzing the thus obtained fuel oil with a reforming catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel oil for a fuel cell, a method for desulfurizing the fuel oil, and a method for producing hydrogen for a fuel cell. More specifically, the present invention provides a petroleum-based hydrocarbon fuel oil that can be easily subjected to desulfurization treatment and is suitable as a raw material oil for a fuel cell. The present invention relates to a desulfurization method for producing fuel oil for fuel cells and a method for effectively producing hydrogen for fuel cells by reforming the fuel oil.

[0002]

2. Description of the Related Art In recent years, new energy technologies have been spotlighted due to environmental problems, and fuel cells have attracted attention as one of the new energy technologies. This fuel cell converts chemical energy into electric energy by electrochemically reacting hydrogen and oxygen, and has the feature of high energy use efficiency.
Practical research is being actively conducted for industrial or automotive use. As the fuel cell, types such as a phosphoric acid type, a molten carbonate type, a solid oxide type, and a solid polymer type are known according to the type of electrolyte used. on the other hand,
As a hydrogen source, liquefied natural gas mainly composed of methanol and methane, city gas mainly composed of natural gas, synthetic liquid fuel composed of natural gas as raw material, and petroleum LP
The use of hydrocarbons such as G, naphtha, kerosene is being studied.

[0003] When a fuel cell is used for consumer or automobile use, the petroleum-based hydrocarbon is easily stored and handled, and is supplied with a hydrogen gas supply system such as a gas station or a store. It is advantageous as a source.
However, petroleum hydrocarbons have a problem that the sulfur content is higher than that of methanol or natural gas. When hydrogen is produced using this petroleum hydrocarbon, a method is generally used in which the hydrocarbon is subjected to steam reforming or partial oxidation reforming treatment in the presence of a reforming catalyst. In such a reforming treatment, the reforming catalyst is poisoned by the sulfur content in the hydrocarbon. Therefore, from the viewpoint of catalyst life, the hydrocarbon is subjected to desulfurization treatment to reduce the sulfur content to 0.1%. It is important that the content be 2 ppm by weight or less.

For this reason, various studies have been made on desulfurization catalysts for petroleum hydrocarbons, and various nickel-based adsorptive desulfurization agents have been developed as effective desulfurization catalysts (JP-B-6-6).
No. 5602, No. 7-115842, No. 7
JP-A-115843, JP-A-2591971, JP-A-2-275701, JP-A-2-204301, JP-A-5-70780, JP-A-6-80972, JP-A-6-91173, Same Hei 6-22857
No. 0). However, there has hitherto not been known any index that indicates the difficulty of desulfurization when desulfurizing petroleum hydrocarbons. If the index of the degree of difficulty of the desulfurization is known, it is considered that the desulfurization treatment can be easily performed to a desired sulfur concentration by controlling the properties of the oil to be desulfurized based on the index.

[0005]

SUMMARY OF THE INVENTION The present invention provides a petroleum-based hydrocarbon fuel oil which can be easily subjected to desulfurization treatment in such a situation and is suitable as a fuel oil for a fuel cell. It is an object of the present invention to provide a desulfurization method for producing a fuel oil for fuel cells having a low sulfur content by desulfurization treatment, and a method for effectively producing hydrogen for fuel cells by reforming the fuel oil. Is what you do.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and have found that petroleum hydrocarbons having an alkyldibenzothiophene content below a certain value are easily desulfurized. It has been found that the object can be achieved by desulfurizing this and further modifying it. The present invention has been completed based on such findings. That is, the present invention provides a fuel oil for fuel cells, wherein the content of the alkyldibenzothiophene is 15 ppm by weight or less, a desulfurization method comprising desulfurizing this fuel oil, and the above-mentioned production method. A method for producing hydrogen for a fuel cell, comprising contacting the obtained fuel oil with a reforming catalyst.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The fuel oil for a fuel cell according to the present invention is a petroleum hydrocarbon which is liquid at normal temperature and normal pressure, for example,
Gasoline, naphtha, kerosene, light oil and the like are used. Among them, kerosene is preferable, and JIS No. 1 kerosene having a sulfur content of 80 ppm by weight or less is particularly preferable. This JI
S1 kerosene is obtained by desulfurizing crude kerosene obtained by distilling crude oil under normal pressure. The fuel oil for a fuel cell of the present invention,
It has an alkyldibenzothiophene content of 15 ppm by weight or less, preferably 10 ppm by weight or less. If the alkyldibenzothiophene content exceeds 15 ppm by weight, desulfurization becomes difficult, and it becomes difficult to reduce the sulfur content to 0.2 ppm by weight or less under ordinary desulfurization conditions.

As described above, by performing desulfurization treatment using a petroleum hydrocarbon having an alkyldibenzothiophene content of 15 ppm by weight or less, the performance of the desulfurizing agent is maximized, and the sulfur concentration can be easily reduced to 0.1%. It can be 2 ppm by weight or less. In the desulfurization method of the present invention, by bringing the petroleum hydrocarbon into contact with a desulfurizing agent, it is possible to produce a fuel oil having a low sulfur concentration, usually 0.2 ppm by weight or less.

In this case, as the desulfurizing agent, a nickel-based desulfurizing agent in which nickel is supported on a suitable carrier is preferably used. The amount of nickel carried in the nickel-based desulfurizing agent is preferably at least 30% by weight as metallic nickel based on the total amount of the desulfurizing agent. If the amount of the metallic nickel is less than 30% by weight, the desulfurization performance may not be sufficiently exhibited. On the other hand, if the supported amount is too large, the ratio of the carrier is reduced, which causes a decrease in the mechanical strength and desulfurization performance of the desulfurizing agent. Considering desulfurization performance and mechanical strength, the more preferred amount of nickel supported is 40 to 8
0% by weight, and more preferably 5% by weight.
It is in the range of 0 to 70% by weight.

[0010] The carrier is preferably a porous carrier, particularly preferably a porous inorganic oxide. Such materials include, for example, silica, alumina, silica-alumina, titania, zirconia, magnesia, zinc oxide, clay, clay and diatomaceous earth. These may be used alone or in combination of two or more. Among these, silica-alumina is particularly preferred. In this desulfurizing agent, other metals such as copper, cobalt, iron, manganese, and chromium may be mixed with nickel, if necessary.

The method for supporting the metal on the carrier is not particularly limited, and any known method such as an impregnation method, a coprecipitation method, and a kneading method can be employed. A desulfurizing agent, which is a preferable desulfurizing agent, in which nickel is supported on a silica-alumina carrier, can be produced by, for example, a coprecipitation method described below. In this coprecipitation method, first, an acidic aqueous solution or an acidic aqueous dispersion containing a nickel source and an aluminum source and a basic aqueous solution containing a silicon source and an inorganic base are prepared. Examples of the nickel source used in the former acidic aqueous solution or acidic aqueous dispersion include nickel chloride, nickel nitrate, nickel sulfate and hydrates thereof. Examples of the aluminum source include aluminum hydrates such as aluminum nitrate, pseudoboehmite, boehmite alumina, bayerite, and gibbsite, and γ-alumina.

On the other hand, the silicon source used in the basic aqueous solution is not particularly limited as long as it is soluble in an alkaline aqueous solution and becomes silica upon firing. For example, orthosilicic acid, metasilicic acid, Sodium salts, potassium salts, water glass and the like can be mentioned. In addition, examples of the inorganic base include carbonates and hydroxides of alkali metals. Next, the acidic aqueous solution or the acidic aqueous dispersion thus prepared and the basic aqueous solution were each added to 50 to 9 parts.
The mixture is heated to about 0 ° C., and the mixture is mixed.
The reaction is completed by maintaining the temperature at about ° C.

Next, the produced solid is thoroughly washed and then subjected to solid-liquid separation, or the produced solid is subjected to solid-liquid separation and thoroughly washed. Drying is performed at a temperature of about 150 ° C. The dried product obtained in this manner is preferably
By firing at a temperature in the range of ~ 400 ° C,
A desulfurizing agent in which nickel is supported on a silica-alumina carrier is obtained. As a method for desulfurizing a petroleum hydrocarbon having an alkyldibenzothiophene content of 15% by weight or less according to the present invention using the nickel-based desulfurizing agent, for example, the following method can be used.

First, hydrogen is supplied in advance to a desulfurization tower filled with the nickel-based desulfurizing agent, and the nickel-based desulfurizing agent is reduced at a temperature of about 150 to 400 ° C. Next, the petroleum hydrocarbon is passed through the desulfurization tower in an upward or downward flow, and the temperature is about normal temperature to about 400 ° C., the pressure is about normal pressure to about 1 MPa · G, and the liquid hourly space velocity (LHS)
V): Desulfurization is performed under the conditions of about 0.02 to 10 hr ^-1 . At this time, if necessary, a small amount of hydrogen may be allowed to coexist. Thus, fuel oil for a fuel cell having a sulfur concentration of 0.2 wt ppm or less can be obtained.

In the method for producing hydrogen for a fuel cell according to the present invention, hydrogen is produced by bringing the fuel oil obtained by the above desulfurization method into contact with a reforming catalyst. In this method, both the steam reforming method and the partial oxidation reforming method can be used, but in the present invention, the steam reforming method is preferable. The catalyst used in the steam reforming method is not particularly limited, and any catalyst may be appropriately selected and used from known catalysts conventionally known as hydrocarbon steam reforming catalysts. As such a steam reforming catalyst,
For example, a carrier in which a noble metal such as nickel, zirconium, ruthenium, rhodium, and platinum is supported on a suitable carrier can be used. One of the above-mentioned supported metals may be supported, or two or more may be supported in combination. Among these catalysts, those supporting ruthenium (hereinafter referred to as ruthenium-based catalyst) are preferable.

In the case of this ruthenium-based catalyst, the supported amount of ruthenium is preferably in the range of 0.05 to 20% by weight, more preferably 0.05 to 15% by weight, and particularly preferably 0.1 to 2% by weight, based on the carrier. % By weight. When the ruthenium is supported, it can be supported in combination with another metal, if desired. Examples of the other metal include zirconium, cobalt, and magnesium.

On the other hand, the carrier is preferably an inorganic oxide, and specific examples thereof include alumina, silica, zirconia, magnesia, and mixtures thereof. Of these, alumina and zirconia are particularly preferred. As the reaction conditions in the steam reforming treatment, the ratio S / C (molar ratio) between steam and carbon derived from the hydrocarbon is usually 2 to 2.
5, preferably 2 to 4, more preferably 2 to 3.

Further, the inlet temperature of the steam reforming catalyst layer is set to 63
It is preferable to carry out steam reforming at a temperature of 0 ° C. or lower, more preferably 600 ° C. or lower. The outlet temperature of the catalyst layer is not particularly limited, but is preferably in the range of 650 to 800 ° C. The reaction pressure is usually in the range of normal pressure to 3 MPa, preferably normal pressure to 1 MPa, and the LHSV is usually 0.1 to 100 h.
^-1 , preferably in the range of 0.2 to 50 h ^-1 . In this way, hydrogen for a fuel cell can be efficiently produced.

[0019]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Preparation Example 1 Preparation of nickel-based desulfurizing agent 50.9 g of nickel chloride was dissolved in 500 ml of water, and 0.6 g of a carrier (alumina) was added thereto.
20 ml of a 1 mol / liter nitric acid aqueous solution was added to adjust the pH to 1 to prepare solution (A). On the other hand, after 33.1 g of sodium carbonate was dissolved in 500 ml of water, 11.7 g of water glass (SiO ₂ concentration: 29% by weight) was added to prepare solution (B). Next, after the above solution (A) and solution (B) were heated to 80 ° C., respectively, they were instantaneously mixed, and the mixture was kept at 80 ° C. for 1 hour.
Stirred for hours. Thereafter, the product was thoroughly washed with 60 liters of distilled water, filtered, and then the solid was removed.
Dry for 12 hours in a blast dryer at 20 ° C, then 300 ° C
For 1 hour to obtain a desulfurizing agent in which 63% by weight of nickel was supported on a silica-alumina carrier.
The desulfurization test of each petroleum hydrocarbon was performed according to the following method.

<Desulfurization Test> 15 ml of the desulfurizing agent obtained in Preparation Example 1 is charged into a stainless steel reaction tube having an inner diameter of 17 mm. Next, the temperature was increased to 120 ° C. in a hydrogen stream under normal pressure, and the temperature was maintained for 1 hour.
For one hour to activate the desulfurizing agent. Next, the temperature of the reaction tube was maintained at 150 ° C., and the hydrocarbon to be treated was passed through the reaction tube under normal pressure at an LHSV of 10 h ⁻¹ , and the sulfur concentration in the treated oil after 5 hours was measured according to JIS K2
Analyze according to 541 microcoulometric titration method. Examples 1 to 3 and Comparative Example 1 A desulfurization test was performed on kerosene having the properties shown in Table 1. Table 1 shows the sulfur content after the desulfurization treatment. The content of alkyldibenzothiophene in kerosene is determined by GC-AED
It was measured by an analytical method (gas chromatograph with an atomic emission detector).

[0021]

[Table 1]

Example 4 15 ml of the desulfurizing agent obtained in Preparation Example 1 was mixed with an inner diameter of 17 m.
m stainless steel reaction tube. Next, the temperature was raised to 120 ° C. in a hydrogen stream under normal pressure, and the temperature was maintained for 1 hour. Then, the temperature was further raised and the temperature was maintained at 380 ° C. for 1 hour to activate the desulfurizing agent. Next, the temperature of the reaction tube was reduced to 15
The kerosene A used in Example 1 was kept at 0 ° C.
HSV2h ^-1 is passed through the reaction tube, and further downstream is a ruthenium-based reforming catalyst (ruthenium loading 0.5% by weight) 3
Steam reforming treatment was performed by a reformer filled with 0 ml. The reforming treatment conditions are as follows: pressure: atmospheric pressure, steam / carbon (S / C) molar ratio: 2.5, LHSV: 1.0 h ⁻¹ , inlet temperature: 500 ° C., outlet temperature: 750 ° C. As a result, the conversion at the outlet of the reformer after the elapse of 200 hours is 100
%Met. The sulfur content of the desulfurized kerosene during this reaction period was 0.2 ppm by weight or less. The conversion rate is expressed by the formula: conversion rate (%) = 100 × B / A (where A is the total amount of carbon in the supplied kerosene (molar flow rate) and B is the reformer outlet gas per hour. This is the total carbon amount (molar flow rate) of the C1 compound in the formula (1). The analysis is based on a gas chromatography method.

Comparative Example 2 A desulfurization treatment and a steam reforming treatment of kerosene were performed in the same manner as in Example 4 except that kerosene D used in Comparative Example 1 was used. As a result, the conversion at the outlet of the reformer was less than 100% after 50 hours, and oil droplets were confirmed at the outlet of the reformer after 70 hours. In addition, 50 hours and 7
The sulfur content in the desulfurized kerosene at the time when 0 hour has passed is 4.4 ppm by weight and 10.0 ppm by weight, respectively.
Met.

[0024]

The fuel oil for a fuel cell according to the present invention has an alkyldibenzothiophene content of not more than 15 ppm by weight, is easily desulfurized, reduces the load on the desulfurizing agent, and has a low sulfur content. It is a fuel oil suitable for use in fuel cells. In addition, the desulfurization treatment of the fuel oil followed by the reforming treatment can prolong the service life of the reforming catalyst.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masahiro Yoshinaka 1280 Kamiizumi Kamiizumi, Sodegaura-shi, Chiba F-term (reference) 4G040 EA03 EA06 EB01 EC03 5H027 AA02 BA01 BA16

Claims (4)

[Claims] 1. An alkyldibenzothiophene content of 1
A fuel oil for a fuel cell, wherein the content is 5 ppm by weight or less. 2. An alkyldibenzothiophene content of 1
The fuel oil according to claim 1, wherein the content is 0 ppm by weight or less. 3. A desulfurization method comprising desulfurizing the fuel oil according to claim 1. 4. A method for producing hydrogen for a fuel cell, comprising, after desulfurization according to the method according to claim 3, contacting the fuel oil with a reforming catalyst.