JPH084741B2 - Gas adsorption decomposition agent - Google Patents

Description

TECHNICAL FIELD The present invention can adsorb and remove offensive odors, harmful gases, and the like, and can reduce the offensive odors, harmful gases, etc. released during heating and regeneration, and thus can be used for a long period of time. The present invention relates to a regenerable gas adsorption decomposing agent that can be used.

2. Description of the Related Art Conventionally, a large number of adsorbents such as activated carbon, bone charcoal, silica gel, activated alumina, zeolite, various types of clay and ion exchange resins have been used for the adsorption and removal of malodors and harmful gases. In particular, activated carbon is a typical adsorbent, has an extremely large surface area, and is composed of innumerable microcapillary groups, so that many odors and harmful gas components can be adsorbed and removed.

Problems to be Solved by the Invention Since an adsorbent such as activated carbon releases the bad odor, harmful gas and the like that have been adsorbed when heated and regenerated, it is necessary to replace the adsorbent in a small-scale deodorizing device.

Means for Solving the Problems In order to solve the above problems, the present invention provides Ln _1-x A _x Co
_1-y M _y O _{3- δ} (Ln is at least one element selected from La, Ce, Pr, Nd, A is at least one element selected from Ca, Sr, Ba, M is Cr, Mn, Fe, Ni , An oxide catalyst represented by at least one element selected from V, O ≦ x ≦ 1, O ≦ y ≦ 1, δ is an oxygen deficiency number), and MgO, an inorganic adsorbent, and a heat-resistant binder are mixed. is there.

Action In the gas adsorption decomposition agent according to the present invention, since MgO chemically adsorbs acidic gas such as NOx, the adsorption amount varies little with temperature compared to activated carbon, and the adsorbed acidic gas can be released at about 400 ° C. it can. Also, MgO is replaced by Ln _1-x A _x Co _{1- y My} O _3-
By mixing with the oxide represented by _δ , Ln _1-x A _x Co
_1-y M _y O _3- CO oxidation and the oxide represented by _[delta], it is possible to improve the adsorption removal capability.

_{Ln 1-x A x Co 1} -y M y O 3- δ oxide represented by acts as a redox catalyst, when heated play gas adsorption decomposing agent
Acidic gas released from MgO, malodorous gas emitted from inorganic adsorbent, harmful gas, etc. are oxidized and reduced to harmless gas.

Example In this example, a case of using an oxide of La _0.5 Sr _0.5 CoO _{3- δ} will be described. La _0.5 Sr _0.5 CoO _{3- δ} is a solution containing metal salts of each component and is precipitated as a mixture of metal oxalates and metal hydroxides using oxalic acid, amines, sodium hydroxide, etc., and overwashed and dried. Then, in air at 800 ℃ 1
It was made by firing for 0 hours. Next, disperse this oxide powder in a magnesium salt solution, generate magnesium hydroxide gel using sodium hydroxide, wash, and wash at 400 ° C.
Was treated for 2 hours to prepare an oxide catalyst mixed with MgO.

The oxide catalyst mixed with MgO, acetylene black carbon, and sodium silicate in a weight ratio of La _0.5 Sr _0.5 CoO ₃ : M
Knead and mold at a ratio of gO: C: SiO = 1: 2: 3: 10, fully dry, and then soak in magnesium chloride aqueous solution to make sodium silicate into SiO ₂ gel and wash with water at 400 ° C. Heat treatment was performed for 2 hours. Silica gel acts as an adsorbent and a binder.

As an evaluation of the gas adsorption decomposer, the adsorption characteristics and the gas concentration generated during heating and regeneration were measured. Regarding the adsorption characteristics, 10 g of a gas adsorption decomposition agent was put in a quartz glass tube, and the gas concentration was measured while contacting various gases at a temperature of 20 to 30 ° C. For comparison, the same measurement was performed for the same volume of activated carbon.

Figure 1 shows the CO removal rate when contacting 800ppm / Air gas at 3 / min. Activated carbon has almost no CO adsorption removal property, whereas the gas adsorption decomposition agent of the present invention removed 70% or more of CO even after 3 hours.

Showed the removal rate of NO ₂ when contacting the NO ₂ 150 ppm / Air gas 3 / min in Figure 2. Regarding the removal rate of NO _2, the gas adsorption decomposition agent according to the present invention was stable 1 hour after aeration and showed a removal rate of 90% or more even after aeration for 3 hours, whereas activated carbon
It fell to about 50%.

Fig. 3 shows the kerosene removal rate when the kerosene was brought into contact with 500 ppm / Air gas at 3 / min. Regarding the removal rate of kerosene, both the gas adsorption decomposition agent of the present invention and the activated carbon showed a removal rate of 95% or more even after aeration for 3 hours.

Next, the gas adsorbing and decomposing agent according to the present invention which adsorbed the above CO, NO ₂ , and kerosene and the activated carbon were heated and regenerated, and the generated gas was measured by a CO, HC and NO _x meter.

3 / min for the gas adsorption decomposition agent according to the present invention that adsorbs CO
The CO concentration was measured by heating to 400 ° C while sending air at, but CO was hardly detected.

FIG. 4 shows the concentrations of CO and HC generated by the heating regeneration of the gas adsorption decomposition agent according to the present invention which adsorbed kerosene and activated carbon. In the heating regeneration, air is brought into contact with the gas adsorption decomposition agent (or activated carbon) according to the present invention which adsorbs kerosene at 3 / min,
The temperature was raised to 400 ° C. in an electric furnace for 30 minutes. The gas adsorption decomposition agent according to the present invention has a maximum HC concentration (about 3
00ppm), and then decreased with increasing temperature. No CO was detected. On the other hand, with activated carbon, the adsorbed kerosene was released almost as it was, so the HC concentration was high, and CO was detected above 200 ° C.

FIG. 5 shows the results of measuring the NO _x concentration released during the heating regeneration of the activated carbon and the gas adsorption decomposition agent of the present invention which adsorbed NO ₂ . The reproducing method was as follows.
Kerosene 500 ppm / Air gas was brought into contact with the gas adsorption decomposition agent (or activated carbon) of the present invention which adsorbed NO ₂ at 3 / min for 1 hour to adsorb kerosene, and then they were placed in a quartz glass tube with one end closed. Moved. The quartz tube was capped with two glass tubes for feeding and exhausting, and the exhaust side was joined with a tube flowing at 3 / min of air and connected to a NO _x meter. Next, close the air supply side and heat the glass tube to 400 ° C for 5 minutes in an electric furnace to 400 ° C.
After holding for 10 minutes, air was sent from the air feeding side at 100 cc / min to perform regeneration while measuring the concentration of NO _x generated during that time.
In the gas adsorption decomposition agent according to the present invention, NO _x is released at the time of temperature rise, but it is much less than activated carbon, and it is 1 at 400 ° C.
After holding for 0 minutes, NO _x is generated even if air is sent from the air supply side at 100cc / min
Although the concentration was several ppm, high concentration of NO _x exceeding 2000 ppm was detected in activated carbon.

6 and 7 show the results of the cycle life test of the gas adsorption decomposition agent according to the present invention. Fig. 6 shows that kerosene 500ppm / Air gas was contacted at 3 / min and the removal rate after 3 hours was measured.
A 100-cycle test was carried out by regenerating by flowing 3 / min air at 400 ° C. for 20 minutes and setting the operation from kerosene adsorption to heating regeneration as one cycle. It is the result of the cycle life test.
The figure shows that CO800ppm / Air gas is contacted at 3 / min and the removal rate after 3 hours is measured, then air is regenerated by flowing 3 / min of air at 400 ° C for 20 minutes, and the operation from CO adsorption to heating regeneration is one cycle. Is the result of the cycle life test of 100 cycles. From the results of Fig. 6 and Fig. 7, the kerosene removal rate is 95% or more, and the CO removal rate is 70% even after 100 cycles of testing.
From the above, it was confirmed that the adsorptive removal capacity hardly decreased.

As described above, the gas adsorptive decomposition agent according to the present invention can remove CO that is hardly adsorbed and removed by activated carbon, has a small amount of bad odor, harmful gas and the like released during heating regeneration, and has almost no adsorptive removal ability even after heating regeneration. Since it does not deteriorate, it can be used for a long time.

Furthermore, in the examples, only the case where Ln is lanthanum and A is strontium is described, but Ln is Ce, Pr, Nd or La, C.
When two or more kinds of e, Pr, Nd are included, A is Ca, Ba or Ca, Sr, Ba
When two or more kinds of M are contained, the same effect was obtained when M, Cr, Mn, Fe, Ni, V or an oxide catalyst containing two or more kinds of M was used.

EFFECTS OF THE INVENTION The present invention can adsorb and remove CO by mixing MgO and an inorganic adsorbent in an oxide catalyst represented by Ln _1-x A _x Co _1-y MyO _{3 -δ} , and further a heat-resistant binder. At the same time, there is little offensive odor, harmful gas, etc. released during heating regeneration, and the adsorption removal capacity is hardly reduced by heating regeneration.
It is a gas adsorption decomposition agent that can be used for a long time.

[Brief description of drawings]

FIG. 1 is a characteristic diagram showing the CO removal rate of one embodiment of the present invention,
Fig. 3 is a characteristic diagram showing NO ₂ removal rate, Fig. 3 is a characteristic diagram showing kerosene removal rate, and Fig. 4 is CO gas and HC released during heating regeneration.
Fig. 5 is a characteristic diagram showing gas concentration, Fig. 5 is a diagram showing NO _x gas concentration released during heating regeneration, Fig. 6 is a characteristic diagram showing kerosene removal rate in a life test, and Fig. 7 is CO in a life test.
It is a characteristic view which shows a removal rate.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B01J 20/20 D 23/78 ZAB M 23/84 ZAB M 23/94 ZAB M

Claims (2)

[Claims] _1. A general formula Ln _1-x A _x Co _{1- y My} O _{3- δ} (Ln is La, C
At least one element selected from e, Pr, Nd, A is Ca, Sr, Ba
At least one element selected from, M is at least one element selected from Cr, Mn, Fe, Ni, V, O ≦ x ≦ 1, O ≦ y ≦ 1, δ
Is a gas adsorption decomposition agent characterized by mixing MgO, an inorganic adsorbent, and a heat-resistant binder with an oxide catalyst represented by the number of oxygen vacancies. 2. The gas adsorbing and decomposing agent according to claim 1, wherein the inorganic adsorbent comprises at least one of carbon, silica gel, zeolite, activated alumina and diatomaceous earth.