JP2001279275A - Method for producing fuel oil for fuel cell and hydrogen for fuel cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing the subject fuel oil capable of effectively producing hydrogen by reforming treatment through suppressing the deterioration of a reforming catalyst due to carbon deposition, and to provide a method for producing hydrogen for fuel cells by using the above fuel oil. SOLUTION: The fuel oil for fuel cells is <=1.0 vol.% in polycyclic aromatic compound content. The method for producing hydrogen for fuel cells comprises catalyzing the above fuel oil with a reforming catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing fuel oil for fuel cells and hydrogen for fuel cells. More specifically, the present invention relates to a fuel cell for a fuel cell, which can suppress the deterioration of a reforming catalyst due to carbon deposition in the production of hydrogen by a reforming treatment, prolong the life of the catalyst, and effectively produce hydrogen. The present invention relates to an oil and a method for producing hydrogen for a fuel cell by a reforming process using 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.

When a fuel cell is used for consumer or automobile use, the above-mentioned petroleum hydrocarbons, especially kerosene, are liquid at normal temperature and normal pressure, and are easy to store and handle. It is advantageous as a hydrogen source because the supply system is in place. In the case of producing hydrogen using a 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 process, it is extremely important in practical use to suppress the deterioration of the reforming catalyst and extend the life.

One of the causes of the deterioration of the reforming catalyst is as follows.
Carbon deposition (coke poisoning) on the catalyst. As a coke source contained in petroleum hydrocarbons, for example, aromatic compounds and cyclic saturated hydrocarbon compounds having two or more rings are known, but carbon deposition on the reforming catalyst is suppressed,
Petroleum hydrocarbons that practically satisfy the life of the reforming catalyst have not been provided so far.

[0005]

SUMMARY OF THE INVENTION Under the above circumstances, the present invention suppresses the deterioration of the reforming catalyst due to carbon deposition in the production of hydrogen by the reforming treatment, thereby extending the life of the reforming catalyst. It is an object of the present invention to provide a fuel cell fuel oil capable of producing hydrogen, and a method for producing fuel cell hydrogen using the fuel oil.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies to develop a fuel oil capable of suppressing the deterioration of a reforming catalyst due to carbon deposition. As a result, the content of aromatic compounds having two or more rings was found. It has been found that the above-mentioned object can be achieved by a fuel oil having a certain value or less, and more preferably, a content of the partial aromatic compound being a certain value or less. The present invention has been completed based on such findings. That is, the present invention provides a fuel oil for a fuel cell, wherein the content of the aromatic compound having two or more rings is 1.0% by volume or less, and preferably the content of the aromatic compound is 16% or less. It is intended to provide a fuel oil for a fuel cell having a capacity of not more than%. The present invention also provides a method for producing hydrogen for a fuel cell, which comprises contacting the fuel oil with a reforming catalyst.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The fuel oil of the present invention is at room temperature,
Petroleum-based gasoline that is liquid at normal pressure, naphtha, kerosene, light oil, etc. are used, among which kerosene is preferred,
In particular, JIS No. 1 kerosene having a sulfur content of not more than 80 ppm by weight is suitable because it is easy to desulfurize to a low sulfur concentration required as fuel oil for fuel cells. This JIS No. 1 kerosene is obtained by desulfurizing crude kerosene obtained by distilling crude oil at normal pressure. As the desulfurization method, desulfurization treatment is preferably performed by a hydrorefining method generally used industrially. further,
It can also be obtained by nuclear hydrogenation or hydrocracking.
As an example of these treatment methods, as a catalyst, a carrier mainly composed of alumina in the form of a mixture of transition metals such as nickel, cobalt, molybdenum and tungsten at an appropriate ratio, in the form of a metal, oxide, sulfide or the like. And a method using a zeolite-based hydrocracking catalyst or the like. The reaction conditions are, for example, a reaction temperature of 250 to 4
00 ° C., pressure 2 to 10 MPa · G, hydrogen / oil molar ratio 2 to 2
10, conditions such as liquid hourly space velocity (LHSV) ^{1 to 5} h ^-1 are used.

In the fuel oil of the present invention, the content of the aromatic compound having two or more rings is 1.0% by volume or less, preferably 0.7% by volume or less, more preferably 0.5% by volume or less. When the content exceeds 1.0% by volume, carbon is remarkably precipitated on the reforming catalyst, and the catalyst is rapidly deteriorated, so that the object of the present invention cannot be achieved. In the present invention, the content of the partial aromatic compound in the fuel oil is preferably 16
% By volume or less, more preferably 14% by volume or less. When the content exceeds 16% by volume, carbon is remarkably precipitated on the reforming catalyst, and the catalyst may be rapidly deteriorated.

Further, the content of the bicyclic or higher cyclic saturated hydrocarbon compound in the fuel oil is preferably 7.0% by volume or less,
It is more preferably at most 5.0% by volume. Since bicyclic or higher cyclic saturated hydrocarbon compounds are easily converted to aromatic compounds, carbon content may be accelerated if contained in more than 7.0% by volume. Since the fuel oil of the present invention having such properties suppresses carbon deposition on the reforming catalyst in the production of hydrogen by the reforming treatment, the life of the catalyst can be extended.

In the method for producing hydrogen for a fuel cell according to the present invention, hydrogen is produced by bringing the aforementioned fuel oil into contact with a reforming catalyst. At this time, in order to suppress the poisoning of the reforming catalyst by the sulfur in the fuel oil, it is important that the sulfur concentration in the fuel oil be 0.2 ppm by weight or less, preferably 0.1 ppm by weight or less. It is. Therefore, when the sulfur content in the fuel oil is higher than the above range, desulfurization treatment can be performed to take measures to reduce the sulfur content. At this time, 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. In consideration of desulfurization performance, mechanical strength, and the like, the more preferable amount of nickel is 40 to 80% by weight, and the more preferable amount of nickel is 50 to 70% by weight.

As the carrier, a porous carrier is preferable, and a porous inorganic oxide is particularly preferable. 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.

As a method for desulfurizing a fuel oil 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 fuel oil is passed through the desulfurization tower in an upward or downward flow, and the temperature is from ordinary temperature to about 400 ° C. and the pressure is from ordinary pressure to
About 1 MPa · G, liquid hourly space velocity (LHSV): 0.0
The desulfurization treatment is performed under the condition of about 2 to 10 hr ^-1 . At this time, if necessary, a small amount of hydrogen may be allowed to coexist.

In the method for producing hydrogen for a fuel cell according to the present invention, 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 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 fuel oil is usually 2 to 5,
Preferably, it is selected in the range of 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.

[0017]

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.
A solution (A) was prepared by adding 20 ml of an aqueous nitric acid solution having a concentration of mol / liter to adjust the pH to 1. On the other hand, water 5
After dissolving 33.1 g of sodium carbonate in 00 ml, 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.

Examples 1 to 3 and Comparative Examples 1 and 2 15 ml of the desulfurizing agent obtained in Preparation Example 1
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
While maintaining the temperature at 0 ° C., each of kerosene A to E having the composition shown in Table 1 was passed through a reaction tube under normal pressure at LHSV2h ⁻¹ , and further downstream, a ruthenium-based reforming catalyst (ruthenium loading 0.5 wt. %) Was subjected to steam reforming treatment using a reformer (quartz reaction tube having an inner diameter of 18 mm) filled with 6.0 ml. The reforming treatment conditions are as follows: pressure: atmospheric pressure, a steam / carbon (S / C) molar ratio of 2, LHSV: 2.3 h ⁻¹ , and average temperature: 650 ° C.

The time required until the following conversion decreased to 50% at the beginning of the reaction was determined and is shown in Table 1. The sulfur content of the desulfurized kerosene during this reaction period was 0.2 ppm by weight or less. As the ruthenium-based reforming catalyst, a catalyst in which 0.5% by weight of ruthenium, 1.0% by weight of cobalt, 5% by weight of zirconia, and 2% by weight of magnesia were supported on an α-alumina carrier on a carrier basis was used. . <Conversion rate> Conversion rate (%) = 100 × B / A (where A is the total carbon amount (molar flow rate) in the supplied kerosene per hour, and B is C1 in the reformer outlet gas per hour. B = CO + CO _{2 in} the total carbon amount (molar flow rate) of the compound
+ CH _4. ). In addition,
The analysis is by gas chromatography.

[0020]

[Table 1] As is clear from Table 1, in Examples 1 to 3, the time until the conversion decreases to 50% of the initial stage of the reaction is significantly longer than that in Comparative Examples.

[0021]

According to the fuel oil for a fuel cell of the present invention, carbon production on the reforming catalyst is suppressed in the production of hydrogen by the reforming treatment, so that the life of the catalyst can be extended.

Claims (4)

[Claims] (1) The content of an aromatic compound having two or more rings is 1.
A fuel oil for a fuel cell, wherein the content is 0% by volume or less. 2. The method according to claim 1, wherein the content of the partial aromatic compound is 1
The fuel oil for a fuel cell according to claim 1, wherein the content is 6% by volume or less. 3. A method for producing hydrogen for a fuel cell, comprising contacting the fuel oil according to claim 1 with a reforming catalyst. 4. The method for producing hydrogen for a fuel cell according to claim 3, wherein the reforming catalyst is a ruthenium-based catalyst.