JP2986830B2 - Engine exhaust gas treatment device - Google Patents

Description

The present invention relates to an exhaust gas processing apparatus for purifying exhaust gas of a gasoline engine or a diesel engine to suppress the emission of carbon dioxide gas and to eliminate the emission of nitrogen oxides. It is about.

(Prior Art) Conventionally, various methods for purifying exhaust gas from an engine have been developed by many researchers. Among them, a plurality of catalysts such as platinum vanadium and platinum rhodium are serially connected to an exhaust gas passage. or carbon dioxide and alongside oxidizing carbon monoxide, nitrogen oxides NOx was something to nitrogen gas N _2. This is already disclosed as a technique represented by Japanese Patent Application Laid-Open No. 63-113112.

(Problems to be Solved by the Invention) The conventional apparatus increases the cost and exhausts carbon monoxide as carbon dioxide, thereby suppressing the emission of carbon dioxide, which is currently causing global warming worldwide. In spite of having to do so, this conventional device does not provide a complete purification measure because carbon monoxide is converted into carbon dioxide gas and discharged.

Further, since exhaust gas must pass through a plurality of special catalysts, the output of the engine is reduced, so that more fuel is required, and as a result, more exhaust gas is generated, and There is a problem that the exhaust gas cannot be purified.

(Means for Solving the Problems) In order to solve the above problems, the present invention is characterized in that magnetite is used as a basic catalyst for exhaust gas as a catalyst. I do.

In the first invention, magnetite is housed in a constant temperature section which keeps the temperature around 250 ° C. to 350 ° C., and a plurality of exhaust gas treatment sections through which gas can come in contact with and pass through the magnetite are provided. An exhaust gas treatment for an engine in which hydrogen from a source or a hydrogen generator is configured to be specially supplied by a switching valve, and configured so that the supply of exhaust gas and hydrogen is reversed at predetermined time intervals. Device.

In the second invention, approximately 250 ° C.
A constant temperature section is maintained at about 350 ° C., and an exhaust gas processing section is provided in the constant temperature section through which magnetite and exhaust gas come in contact with each other, and the exhaust gas and hydrogen are alternately fed into the magnetite contact passage. An exhaust gas treatment device for an engine configured as described above, wherein the hydrogen-side supply time is shorter than the exhaust gas supply time.

(Function) The basic function of each invention is to effectively utilize magnetite (ferrite). That is, the molecular structure of magnetite is divalent iron (Fe) having two cations.
² ★) One trivalent iron (Fe ³ ★) and two trivalent irons (Fe ³ ★) are present, resulting in a total of eight positive charges, which are combined with four oxygen (O ² ) holding anions. Fe ₃ O _{4 is} a stable magnetite, which reacts with hydrogen (H ₂ ) at around 300 ° C. to convert oxygen (O ₂ ) to water (H ₂
O) escapes to give oxygen-deficient active magnetite. That is, the active magnetite is hereinafter referred to as oxygen-deficient magnetite (Fe ₃ O ₄ -x). At around 300 ° C., the activated magnetite is in a state capable of performing a scientific reaction requiring oxygen molecules.

Therefore, when carbon dioxide gas is reacted with the oxygen-deficient magnetite in this state, the magnetite becomes inactive with carbon, and when hydrogen reacts with this inert magnetite, active magnetite and water are rapidly formed. If this is made into a scientific reaction formula, it is Fe ₃ O ₄ + yH ₂ → Fe ₃ O ₄ _x + yH ₂ O Fe ₃ O ₄ _x + 1 / 2yCO ₂ → 1 / 2yC + Fe ₃ O ₄ .

The operation of the basic invention is as described above. However, in the first invention, a plurality of purification reaction device parts are provided to efficiently purify exhaust gas in a continuous state, and an apparatus for purifying exhaust gas is provided. Further, the efficiency of the apparatus being activated is alternately switched to activate the magnetite which has become inactive.

In the second invention, when oxygen-deficient magnetite is combined with oxygen in exhaust gas to form an inactive magnetite from oxygen-deficient magnetite to oxygen-deficient magnetite again, only the vicinity of the surface of the magnetite is converted to oxygen-deficient magnetite to rapidly react. Since it is sufficient to gasify the exhaust gas, unnecessary supply of hydrogen is eliminated, and the reaction time with the exhaust gas is lengthened as much as possible, thereby purifying the exhaust gas efficiently.

Embodiment An embodiment of the present invention will be described in detail. Reference numeral 1 denotes an engine, and reference numeral 2 denotes an exhaust passage. 3 is a hydrogen generator,
The structure disclosed in FIG. 1 is configured to generate hydrogen by electrolysis of water. Reference numeral 4 denotes a hydrogen extraction passage. Reference numeral 5 denotes a switching valve, which is a two-way selection type valve which can exchange two flow passages with each other. Reference numeral 6 denotes an on-off valve. Reference numerals 7 and 8 denote exhaust gas treatment units provided in flow paths 9 and 10 communicating with the two outlet ports of the switching valve 5, respectively, and exhaust pipes detachably connected to tips of the flow paths 9 and 10. A cell 14 filled with magnetite 13 in a ventilated manner at the inlet portion of 11, 12 is further provided, and a heater 15 is provided on an outer peripheral portion of exhaust pipes 11 and 12 in which the cell 14 is provided, and the magnetite 13 is provided therein. Is maintained at a temperature around 300 ° C. This heater 15 is not necessary when the temperature is maintained at 300 ° C. by the engine heat.

The operation of the above example will be described in detail. In FIG. 1, the exhaust gas mixed with carbon dioxide CO ₂ and nitrogen oxide NOx discharged from the engine 1 flows through the switching valve 5 to the flow path 9 while the hydrogen generator The hydrogen H ₂ produced in 3 flows through the flow path 4 and the on-off valve 6 to the flow path 10 via the switching valve 5. Then, in the exhaust gas processing section 7 connected to the flow path 9 through which the exhaust gas flows, if the magnetite 13 is activated through hydrogen H _{2 in} advance, the magnetite itself is transformed into oxygen-deficient magnetite Fe ₃ O ₄ _x. , carbon dioxide CO ₂ oxygen O ₂ or oxygen NOx
Ox is taken in by the oxygen-deficient magnetite, and carbon C is deposited or jumps out as nitrogen gas N ₂ .

On the other hand, in the exhaust gas processing unit 8 into which the hydrogen H ₂ is sent,
Hydrogen H ₂ acts on the inactivated magnetite Fe ₃ O ₄ , and this hydrogen H ₂ drives out oxygen O ₂ in the magnetite to become oxygen-deficient magnetite.

That is, on the exhaust gas processing unit 8 side, purification is performed by causing a chemical reaction of Fe ₃ O ₄ + H ₂ → Fe ₃ O ₄ —x + xH ₂ O or Fe ₃ O ₄ —x + 2NOx → N ₂ + Fe ₃ O ₄ .

It should be noted that nitrogen oxide NOx reacts very quickly, and purification of nitrogen oxides is performed promptly.
As for CO ₂ , the reaction is slow, and it is desirable that the exhaust gas treatment section be pressurized.

After continuing the state of FIG. 1 for a predetermined time (approximately 1 to 3 minutes is appropriate) (FIG. 2 when shown in a diagram), the switching valve 5 is switched as shown in FIG. In the flow path 10, hydrogen H ₂
Is switched to flow through the flow path 9, the exhaust gas is purified by the same operation as described above.

Then, the opening and closing valve 6 of hydrogen H ₂ are side infeed is, if in conjunction with the switching of the switching valve 5 so as to closed to a predetermined time (10 seconds to 30 seconds) opening, waste of hydrogen H ₂ Can be eliminated.

(Effects of the Invention) According to the first invention, during a purification reaction of an exhaust gas in a specific exhaust gas processing unit, magnetite of another exhaust gas processing unit that has completed the purification operation is reduced to an oxygen-deficient magnetite activated. The exhaust gas can be continuously purified, and the purification efficiency can be improved.

According to a second aspect of the invention, it is possible to reduce the amount of hydrogen H ₂ to change the magnetite to oxygen defect magnetite.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a sectional view of a main part, FIG. 2 is a simplified view of the main part, and FIG. 3 is a simplified view of a main part. In the figure, 1 is an engine, 2 is an exhaust passage, 3 is a hydrogen generator, 4 is a hydrogen extraction passage, 5 is a switching valve, 6 is an on-off valve, 7, 8 is an exhaust gas processing section, and 9 and 10 are flow paths. , 11 and 12 indicate exhaust paths.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F01N 3/10 F01N 3/28 B01D 53/34 B01J 23/745

Claims (2)

(57) [Claims] A magnetite is housed in a constant temperature section which keeps the temperature around 250 ° C. to 350 ° C., and a plurality of exhaust gas treatment sections are provided, through which gas can come into contact with and pass through the magnetite, and an exhaust gas from an engine and a hydrogen source or An exhaust gas treatment device for an engine, wherein hydrogen from a hydrogen generator is separately supplied by a switching valve, and the supply of exhaust gas and hydrogen is reversed at predetermined time intervals. 2. A constant temperature section which is maintained at about 250 ° C. to 350 ° C. in the middle of the exhaust gas passage, and an exhaust gas treatment section through which magnetite and exhaust gas come into contact with and pass through the constant temperature section. An exhaust gas treatment device for an engine, wherein the exhaust gas and the hydrogen are alternately fed into a magnetite contact passage, and the time for feeding on the hydrogen side is shortened with respect to the time for sending the exhaust gas.