JPH10265783A - Device for modifying fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject device capable of reducing the contents of polycyclic aromatic compounds in a fuel and not requiring a treatment for regenerating a porous material by carrying a catalyst for decomposing the polycyclic aromatic components on the adsorbing surfaces of the porous material having a specific average pore diameter or on places near to the adsorbing surfaces. SOLUTION: A catalyst for decomposing polycyclic aromatic compounds is carried on the adsorbing surfaces of a porous material having the adsorbing surfaces and having an average pore diameter of 0.5-100 nm or on places near to the adsorbing surfaces. A fuel-modifying device 10 filled with the grains of the porous material carrying the catalyst is disposed between a fuel-supplying system 20 and a combustion system 30, and the retention of a fuel in the fuel- modifying device 10 for 20 min or longer enables to substantially perfectly remove the polycyclic aromatic compounds. When a photo-catalyst is used as the catalyst and irradiated with UV light, substances adsorbed on the catalyst are released from the adsorbing surfaces, thereby enabling to prevent the deterioration in the degree for removing the polycyclic aromatic compounds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a fuel reformer for reducing the content of a polycyclic aromatic compound in a fuel.

[0002]

2. Description of the Related Art From the viewpoint of air pollution control, it is an urgent social need to purify exhaust gases from various combustion systems. The combustion systems to be used here are extremely diverse, such as internal combustion engines such as automobiles, aircraft and ships, boilers such as power plants, combustion furnaces such as incineration facilities and treatment facilities, and heaters for commercial and domestic heating. The target fuels are mainly petroleum fuels, such as heavy oil, light oil, kerosene, and gasoline.

[0003] In response to such social demands, various exhaust gas purification measures have been promoted in the field of automobiles.
Diesel engines are also an important subject. Of particular note in the case of a diesel engine, in the exhaust gas, carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NO _X), sulfur dioxide (SO ₂₎ gaseous contamination such as In addition to substances, it contains particulate matter (PM) called diesel black smoke. In particular, since particulate matter emitted from a diesel engine contains polycyclic aromatic hydrocarbons (PAH) which are considered to be highly carcinogenic, it is extremely difficult to reduce the amount of particulate matter emitted. is important.

It is already known that the amount of particulate matter generated is closely related to the amount of polycyclic aromatic compound in fuel. Therefore, it is considered that reducing the amount of the polycyclic aromatic compound in the fuel is effective in reducing the emission of the particulate matter. As a fuel reforming method for reducing the amount of polycyclic aromatic compounds in fuel, for example, “Environmental Conservation Research Results Collection” (vol.199
4, 37-II-1 to 37-II-15), a method of increasing flammability by catalytic treatment of aromatic rings to reduce the generation of particulate matter, and adsorption of polycyclic aromatic compounds Separation methods have been implemented. In particular, the method using adsorption separation is effective for polycyclic aromatic compounds having low reactivity to the catalyst treatment, and the above-mentioned collection of results also describes a method for performing adsorption separation using a porous material.

However, if the porous body is saturated with the adsorbed substance, the effect of the removal by the adsorption is lost. If the porous body is to be regenerated, it is burned at 400 to 500 ° C. or heated at a high temperature. Pressure treatment is required. For that purpose, for example, remove the porous body from the adsorption device in the car,
It must be transferred to another furnace and subjected to high-temperature treatment. Such high-temperature processing must be performed in the form of a processing plant of a certain scale, and cannot be performed in a form that can be mounted on a vehicle (on-board). Even if regeneration is performed by plant treatment, incineration equipment and a fire source are required, which not only increases costs, but also completely incinerates high-concentration polycyclic aromatic compounds adsorbed on the porous body. Purification in itself requires advanced technological development.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel reformer which does not require a porous body for regeneration treatment for adsorbing a polycyclic aromatic compound.

[0007]

In order to achieve the above object, a fuel reformer of the present invention comprises a porous material having an adsorption surface and having an average pore diameter of 0.5 to 100 nm; And a catalyst for decomposing a polycyclic aromatic compound disposed on or near the surface. The fuel reformer of the present invention adsorbs the polycyclic aromatic compound in the fuel to the adsorption surface of the porous body, and decomposes and desorbs the adsorbed polycyclic aromatic compound by the catalyst disposed on the adsorption surface or in the immediate vicinity thereof. Since the porous body is separated, the porous body is not saturated by the adsorption of the polycyclic aromatic compound, or the saturation can be eliminated immediately. Since the monocyclic aromatic compound generated by the decomposition of the polycyclic aromatic compound easily burns, the generation of particulate matter is reduced.

When the average pore diameter of the porous body is less than 0.5 nm, the adsorption effect is reduced because the polycyclic aromatic compound is unlikely to enter the pores. Decrease. FIG. 1 shows that a silica mesopore material having various average pore diameters was used as a porous body.
The result of having performed the adsorption removal experiment of 3 to 3 ring aromatic hydrocarbons is shown. As can be seen from the results, the average pore diameter is 0.5 n
In the range of m to 100 nm, a removal rate of 5% or more can be secured. Furthermore, a removal rate of 10% or more is obtained when the average pore diameter is 1 nm to 50 nm, a removal rate of 50% or more when the average pore diameter is 1.5 nm to 10 nm, and a removal rate of 90% or more when the average pore diameter is 2 to 7 nm.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The material of the porous body used in the fuel reforming apparatus of the present invention may be any porous material that is not eroded or decomposed by the fuel to be reformed and the decomposition catalyst, for example, silica mesopore material. Ceramics and inorganic materials such as zirconium phosphate, zeolite and sepiolite are typical, but not limited thereto, and porous metals such as porous metals and acetal copolymers may be used. The shape or form of the porous body need not be particularly limited, and may be any of powder, columnar pellets, granulated spheres, blocks, fibers, and the like.

[0010] The reaction for decomposing the polycyclic aromatic compound is not particularly limited, but typically the decomposition can be carried out by an oxidation reaction. As oxidation catalysts therefor, for example, manganese dioxide (MnO ₂ ), potassium permanganate (KM
nO ₄ ), manganese sulfate + ascorbic acid (MnSO ₄ +
C ₆ H ₈ O ₆ ), iron chelate compounds and the like can be used.

A photocatalyst can be used as a catalyst for decomposing a polycyclic aromatic compound. Examples of the photocatalyst include titanium oxide (TiO ₂ ) and zinc oxide (Zn).
O) and the like can be used. Although the photocatalyst exemplified here is generally known as an oxidation catalyst, in the present invention, of course, even if the photocatalyst acts as a catalyst other than the oxidation catalyst, it acts as a catalyst for decomposing the polycyclic aromatic compound. Any photocatalyst can be used.

In particular, it is preferable to use a photocatalyst as a catalyst because the decomposition reaction can be performed at an optimum period by controlling the timing of light irradiation. For example, if a photocatalyst is irradiated with light in synchronization with a running period after starting and accelerating a diesel engine, that is, a stable combustion period, a decomposition reaction is performed to burn decomposition substances (especially monocyclic aromatic compounds) most efficiently. Therefore, the amount of particulate matter generated can be suppressed to a minimum.

When a photocatalyst is used, it is preferable that the multi-light body has ultraviolet transmittance, since ultraviolet light can easily reach the inside of the multi-light body, so that the catalytic action can be further utilized. less than,
The present invention will be described in more detail by way of examples with reference to the accompanying drawings.

[0014]

【Example】

Embodiment 1 FIG. 2 shows an example of a fuel reforming apparatus according to the present invention. The fuel reformer 10 is disposed between a fuel supply system 20 such as a fuel tank and a combustion system 30 such as an engine or a combustion furnace.

A large number of catalyst-carrying porous particles 3 for adsorbing and decomposing according to the present invention are accommodated in the closed vessel 1 of the fuel reformer 10. Each of the catalyst-supporting porous particles 3 has a porous body made of silica mesopore material having a particle size of 0.5 mm to 1 mm as a base material, and titanium oxide as a photocatalyst is applied and supported on the outer surface and the inner walls of the pores. is there. The closed container 1 is connected to the fuel supply system 20 at one end of the fuel inlet 4 and to the combustion system 30 at the other end of the fuel outlet 5 via the separate filter 2.

Ultraviolet light from an ultraviolet lamp 6 disposed outside the container 1 can be applied to the catalyst-carrying porous particles 3 through the transparent window 1A of the closed container 1. When a normal oxidation catalyst is used instead of the photocatalyst, the ultraviolet lamp 6 and the transparent window 1A are unnecessary. In the case of the fuel reformer shown in FIG. 2, the capacity of the closed vessel 1 can be set as follows.

FIG. 3 shows that 2 g of the porous particles 3 are
The relationship between the elapsed time after charging into 0 cc and the removal rate of the 2- or 3-ring aromatic hydrocarbon in the gas oil is shown. In this case, the two- or three-ring aromatic hydrocarbons are almost completely removed 20 minutes after the introduction. Therefore, if the capacity of the sealed container 1 in FIG. 2 is set so that the residence time of the fuel in the container is 20 minutes or more, a removal rate of almost 100% can be secured.

For example, if the fuel transport rate is 0.1 liter /
In the case of minutes, 0.1 liter / minute × 20 minutes = 2 liters, so that the capacity of the sealed container 1 may be 2 liters or more. However, the fuel reforming apparatus of the present invention does not have to be installed separately from the fuel supply system as shown in FIG.
In this case, the removal rate increases along the curve in FIG. 3 with the lapse of time after the fuel is supplied into the fuel tank, and a removal rate of almost 100% is obtained after the lapse of 20 minutes.

In the apparatus shown in FIG. 2, an experiment was conducted to treat light oil at a transportation rate of 0.1 liter / min. FIG. 4 shows the relationship between the elapsed time from the start of the treatment and the removal rate of the 2- or 3-ring aromatic hydrocarbon. The removal rate increased as indicated by the solid line in FIG. 4 with the lapse of the processing time, and reached almost 100% after the lapse of 4 hours. Thereafter, when ultraviolet irradiation was not performed for comparison, the removal rate sharply dropped as shown by the broken line in FIG.
It decreased to nearly 0% in one hour. This indicates that the adsorption by the porous particles 3 is saturated and the adsorption is not performed.

On the other hand, according to the present invention, the processing time 4
When the ultraviolet lamp 6 was turned on at the time point and the ultraviolet irradiation was continued for one hour, as shown by the solid line in the area after the elapsed time of four hours in FIG. 4, the removal rate remained constant at almost 100%. . This is because the adsorption function was once saturated after 4 hours, but the adsorbed substance (2 to 3
(Aromatic hydrocarbon) was decomposed and desorbed from the adsorption surface, indicating that the adsorption function was restored.

As shown in this embodiment, when a photocatalyst is used, for example, light is irradiated in a timely manner in synchronization with the operation time of a diesel engine to cause a catalytic function to function, and the polycyclic aromatic compound is decomposed and decomposed in a timely manner. By separating, the generation of particulate matter can be efficiently reduced. In FIG. 5, (1)
In the case where the fuel reforming process is not performed and the case where (2) the fuel reforming is performed using the photocatalyst according to the present invention, in the process from the start of the diesel engine to the steady running through the acceleration,
5 shows changes in the engine speed and the amount of generated particulate matter.

As shown in FIG. 5A, the amount of particulate matter generally increases at the start of the engine and at the time of acceleration, and decreases at a stable running (stable combustion) period and changes at a constant level. . As shown in FIG. 5 (2), when a photocatalyst is used in the fuel reformer of the present invention, the polycyclic aromatic compound, which is a source of particulate matter, is adsorbed by the porous material at the time of startup and acceleration. At the time when the vehicle is trapped, the running is stable and the stable combustion period is started (at the time point A in FIG. 5 (2)), the adsorbed polycyclic aromatic compound is decomposed by operating the photocatalyst by irradiating light. Let go. Since the monocyclic aromatic compound generated by the decomposition of the polycyclic aromatic compound can be easily burned, the amount of particulate matter generated can be reduced by burning it during the stable burning period.

That is, when the fuel is not reformed, a large amount of particulate matter is generated at the time of starting and accelerating the engine as shown in FIG. 5 (1). to continue. On the other hand, by performing the fuel reforming according to the present invention, as shown in FIG. 5 (2), the amount of particulate matter generated at the time of starting the engine and at the time of acceleration can be significantly reduced, and the particulate matter during the stable running period can be reduced. Since the amount of generated substances can also be suppressed to a low level, the amount of generated particulates is reduced over the entire period of engine operation.

FIG. 6 schematically shows the adsorption process of a polycyclic aromatic compound by the catalyst-supporting porous material of the present invention. For ease of illustration, the porous body is shown as a model having one hole, but of course, the porous body actually has countless holes. For simplicity, only the inner wall of the hole will be described, but the same applies to the outer surface. As shown in FIG. 6 (1), light oil containing a polycyclic component (two rings in the figure) comes into contact with the porous body having a photocatalyst supported on the outer surface and the inner wall of the pores, and as shown in FIG. Fig. 6
As in (3), the polycyclic component and a part of the other components (C ₁₅
More linear paraffins and branched paraffins, etc.), adsorbed on pores inner wall and the photocatalyst carrying the balance (C ₁₄ or less linear paraffin) goes through it.

FIG. 7 schematically shows the decomposition and elimination processes of the polycyclic aromatic compound by the catalyst-supporting porous material of the present invention.
The polycyclic component (two rings in the figure) adsorbed on the inner wall of the pores of the catalyst-supporting porous body as shown in FIG. 7 (1) is decomposed by irradiating light to make the photocatalyst function as shown in FIG. 7 (2). Then, it is desorbed as a single ring, and is discharged from the porous body as shown in FIG.
The pore inner wall is released as an effective adsorption surface, and the porous body is regenerated.

The monocyclic component discharged from the porous body is easily burned by the subsequent combustion system, so that the generation of particulate matter is reduced. As illustrated, the component other than the polycyclic component (C ₁₅ or more linear paraffins and branched paraffins, etc.), as well as decomposition, desorption is discharged, easily burned. FIG. 8 shows a transmission electron micrograph of a silica mesopore material supporting titanium oxide as an example of the catalyst-supporting porous body according to the present invention. The countless white spots observed in the photograph of FIG. 8 are pores of the silica mesopore material. Although not identifiable in the photograph of FIG. 8, the individual holes are hexagonal columns as schematically shown in FIG. 9, and titanium dioxide (TiO ₂ ) as a photocatalyst is supported on the outer surface and the inner wall of the holes. . In the fuel reformer of the present invention, the catalyst may be supported on a part or the entire surface of the porous body as described above. It may be arranged. As a specific mode to be disposed immediately, it can be in a state of being mixed with a porous body.

Although the fuel reformer of the present invention has been described above assuming that diesel fuel for a diesel engine is a typical application, the application of the present invention is not particularly limited to this. If the fuel contains at least some aromatic compounds, the effect can be obtained. That is, a car,
For petroleum fuels used in internal combustion engines such as aircraft and ships, boilers such as power plants, combustion furnaces such as incinerators and treatment facilities, and heaters for business and household heating, heavy oil, light oil, kerosene, and gasoline It is applicable regardless of. In the case of gasoline, the content of the polycyclic aromatic compound is small, and the emission of the polycyclic aromatic compound itself can be reduced although the amount of black smoke as a combustion substance is not so large. [Embodiment 2] Fig. 10 shows an example in which the fuel reformer of the present invention is applied to a household oil fan heater. This is a type in which the reformer 10 of the present invention is built in a tank 20 of kerosene as a fuel, and irradiates ultraviolet rays from an ultraviolet lamp 6 to the photocatalyst-supporting porous particles 3 through a transparent window 1A. For example, by irradiating with ultraviolet rays for 10 minutes per hour, it is possible to reduce black smoke at the time of ignition and unpleasant odor at the time of ignition / extinguishing.

Since the fuel reforming apparatus of the present invention has a so-called self-regeneration ability by having a catalyst for decomposing polycyclic aromatic compounds, it is necessary to remove it and transfer it to another plant for regeneration treatment. Since it is not used, it is particularly suitable for in-vehicle use (on-board use) of automobiles and the like. Further, in addition to the main effect that the present invention can greatly reduce the amount of particulate matter generated by fuel reforming, the following secondary effects can be obtained with the main effect.

That is, since the difficult-to-burn components in the fuel are reduced, the combustion efficiency is improved, and the fuel efficiency is improved. For example,
When applied to a 1.8-liter diesel engine passenger car, fuel efficiency was improved by 10%, and when applied to a garbage incinerator using kerosene as fuel, fuel efficiency was improved by 7%. Also,
Since the adhesion of residual combustion substances to the parts that come into direct contact with the combustion flame is reduced, the initial combustion performance can be maintained for a long time.

Further, since the amount of unburned substances in the exhaust gas is reduced, deterioration of the exhaust gas purifying catalyst can be reduced and the life can be extended. For example, improved when applied to a diesel engine for an automobile, the NO _X catalyst for treating poisoning or catalytically active component by the sulfur compounds, the time until purification performance degradation due to adhering to the catalyst surface of the unburnt doubles did.

[0031]

As described above, according to the present invention,
Provided is a fuel reformer that does not require a porous body regeneration treatment for adsorbing a polycyclic aromatic compound.

[Brief description of the drawings]

FIG. 1 is a graph showing a relationship between an average pore diameter of a porous body and a removal rate of a 2- to 3-ring aromatic hydrocarbon.

FIG. 2 is a cross-sectional view showing one configuration example of a fuel reformer according to the present invention.

FIG. 3 is a graph showing a relationship between an elapsed time after pouring porous particles into light oil and a removal rate of a 2- to 3-ring polycyclic aromatic compound in the light oil.

FIG. 4 is a graph showing the relationship between the elapsed time from the start of the treatment in the reformer of FIG. 2 and the removal rate of 2 to 3 ring aromatic hydrocarbons.

FIG. 5 is a diagram showing a process from start of a diesel engine to acceleration and steady running after (1) no fuel reforming process and (2) fuel reforming using a photocatalyst according to the present invention. 5 is a graph showing changes in the engine speed and the amount of particulate matter generated in the above.

FIG. 6 is a cross-sectional view schematically showing a process of adsorbing a polycyclic aromatic compound by the catalyst-supporting porous body of the present invention.

FIG. 7 is a cross-sectional view schematically showing the decomposition and elimination processes of a polycyclic aromatic compound by the catalyst-supporting porous body of the present invention.

FIG. 8 is a transmission electron micrograph of a silica mesopore material supporting titanium oxide as an example of a catalyst-supporting porous body according to the present invention.

FIG. 9 is a perspective view schematically showing pores observed as countless white spots in the photograph of FIG. 8, and a catalyst supported on the outer surface and inner wall thereof.

FIG. 10 is a sectional view showing an example of a household petroleum fan heater in which the fuel reformer of the present invention is incorporated in a kerosene tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Closed container 1A ... Transparent window 2 ... Separate filter 3 ... Porous particle which carried the catalyst 4 ... Fuel inlet 5 ... Fuel outlet 6 ... Ultraviolet lamp 10 ... Fuel reformer 20 ... Fuel supply system (fuel tank etc.) 30 … Combustion system (engine, combustion furnace, etc.)

Claims (4)

[Claims] Claims: 1. An adsorbent surface having an average pore diameter of 0.5 to
A fuel reformer comprising: a porous body having a thickness of 100 nm; and a catalyst for decomposing a polycyclic aromatic compound disposed at or immediately adjacent to the adsorption surface. 2. The fuel reformer according to claim 1, wherein the catalyst is an oxidation catalyst. 3. The fuel reformer according to claim 1, wherein the catalyst is a photocatalyst. 4. The fuel reformer according to claim 3, further comprising means for irradiating the photocatalyst with light.