JP2001294415A - Method of removing residue in liquefied gas and regenerating method of activated carbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of removing residue in a liquefied gas using an adsorbent capable of being regenerated at a lower temperature compared to the conventional one and a method of regenerating the adsorbent. SOLUTION: The method of removing the residue in the liquefied gas, is performed by allowing the liquefied gas to contact with a packed layer, in which activated carbon carrying platinum is filled, to adsorb the residue to the activated carbon. In the regenerating method of the adsorbent, is performed by oxidize the residue in the liquefied gas, which is adsorbed by the activated carbon, with oxygen to regenerate the activated carbon. The removing method of the residue in the liquefied gas has a removing process of the residue in the liquefied gas to adsorb the residue to the activated carbon by allowing the liquefied gas to contact with a packed layer, in which activated carbon carrying platinum is filled, and an activated carbon regenerating process to regenerate the activated carbon by oxidizing the residue in the liquefied gas, which is adsorbed by the activated, with oxygen and the processes are continuously repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for removing residues in a liquefied gas such as a liquefied petroleum gas by adsorbing the residue on an adsorbent (activated carbon carrying platinum), and a method for regenerating the adsorbent. .

[0002]

2. Description of the Related Art Liquefied petroleum gas (hereinafter also referred to as "LP gas") is mainly composed of butane or the like. L
If a residue (oil) is contained in the P gas, for example, when a metamorphic gas is generated and reacted, soot adheres to the nickel catalyst surface to deteriorate the catalyst, block the vaporizer of a taxi, or generate a turbine for power generation. This can cause troubles in piping and equipment by closing nozzles. Therefore, the LP gas has been conventionally gasified, the residue is separated, and then reliquefied to remove the residue in the LP gas.

As such a removing method, for example, a method in which a liquefied gas such as LP gas is brought into contact with activated carbon in a liquid phase and a residue is adsorbed on activated carbon to remove the residue is reported as an economical and efficient method. (For example, Japanese Patent Application No. 7-83)
See No. 595. ).

[0004]

However, a boiling point of 3
In order to regenerate the activated carbon adsorbing the residue at 50 ° C. or higher, a regenerating treatment at a high temperature is required regardless of whether the on-site method or the off-site method is adopted. For example, in the off-site regenerating method described in Japanese Patent Application No. 7-83595, the regenerating process is performed using a regenerating gas at 300 ° C. to 600 ° C., usually 500 ° C.

[0005] Further, since it is necessary to re-activate the activated carbon, the burden on the activated carbon is large, and the adsorption loss such as weight loss and strength of the adsorbent, and the amount of adsorption due to changes in the pore diameter and pore volume are reduced. This causes a change in the physical properties of the agent and a decrease or change in the adsorption performance.

[0006] For example, about 10% by weight of activated carbon is lost by a normal regeneration treatment, and the activated carbon must be added when reused. Further, in addition to the addition of the activated carbon, high-temperature regeneration is performed, so that regeneration equipment costs and regeneration operation costs increase.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, to develop an adsorbent which can be regenerated at a lower temperature than before, and to provide a method for removing a residue in a liquefied gas using the adsorbent. And a method for regenerating the adsorbent.

[0008]

Under such circumstances, the inventors of the present invention have conducted intensive studies and as a result, the liquefied gas was brought into contact with a packed bed filled with activated carbon loaded with platinum, and the activated carbon was allowed to adsorb residues. Then, the present inventors have found that the residue in the liquefied gas can be easily removed, and that the residue adsorbed on the activated carbon can be regenerated at a lower temperature than the conventional one by oxidizing with oxygen, and the present invention has been completed. .

That is, the present invention relates to a method for removing a residue in a liquefied gas, wherein the residue is adsorbed to the activated carbon by contacting the liquefied gas with a packed bed filled with activated carbon carrying platinum. It is intended to provide a method for removing a residue in a liquefied gas.

[0010] Further, the present invention provides a method wherein the liquefied gas is brought into contact with a packed bed filled with activated carbon carrying platinum.
An object of the present invention is to provide a method for regenerating an adsorbent, wherein the activated carbon is regenerated by adsorbing the residue on the activated carbon and oxidizing the residue adsorbed on the activated carbon with oxygen.

[0011] Further, the present invention provides a method for bringing a liquefied gas into contact with a packed bed filled with activated carbon carrying platinum,
A step of removing the residue in the liquefied gas in which the residue in the liquefied gas is adsorbed by the activated carbon; and a step of oxidizing the residue in the liquefied gas adsorbed in the activated carbon by oxygen to thereby regenerate the activated carbon. And a method for removing residues in the liquefied gas by continuously repeating these steps.

According to the present invention, there is provided a method for removing residues from a liquefied gas such as LP gas using an adsorbent which can be regenerated at a lower temperature than in the past, and a method for regenerating the adsorbent.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention, as described above,
(1) A method for removing residues in a liquefied gas, wherein activated carbon is loaded with platinum as an oxidation catalyst as an adsorbent. (2) The adsorbent adsorbing the residues is oxidized with oxygen and adsorbed. (3) a method for regenerating an adsorbent, characterized by selectively removing only the residue by oxidation reaction.
This is a method of removing residues in a liquefied gas by repeatedly repeating a step of adsorbing and removing residues in a liquefied gas using activated carbon carrying platinum and a step of regenerating the activated carbon to which the residues have been adsorbed.

FIG. 1 shows an example of an apparatus for carrying out the present invention.
Is shown as a conceptual diagram. In FIG. 1, what is drawn in the center is
2 having an adsorption tower 1a and an adsorption tower 1b filled with an adsorbent
In the tower type adsorption tower, the residue removal step and the adsorbent regeneration step can be performed simultaneously. In the adsorption tower 1a, for example, by contacting LP gas containing the residue with an adsorbent (activated carbon carrying platinum), the residue is adsorbed on the activated carbon to obtain LP gas from which the residue is removed. (Residue removal step). At this time, in the adsorption tower 1b, the activated carbon can be regenerated by passing an oxygen mixed gas at a predetermined temperature through the adsorbent having adsorbed the residue and selectively oxidizing and removing only the residue (adsorbent regeneration step). ). That is, this apparatus can be operated continuously by repeating the above operations.

The adsorbent used in the present invention may be any adsorbent that adsorbs the residue and can be regenerated by oxygen oxidation. In the present invention, activated carbon carrying platinum is used as the adsorbent. The type, size, shape, etc. of the activated carbon are not particularly limited as long as they can support platinum and can adsorb the residue, but they are packed in an adsorption tower and brought into contact with LP gas. In order to efficiently remove the residue in the LP gas, it is preferable that the residue adsorb a large amount of the residue.

Further, since the LP gas is passed smoothly and is used a plurality of times by the regeneration treatment, a solid having a certain degree of breaking strength is more preferable than a powder. That is, as long as it has a residue adsorption amount of a certain level or more and can withstand the residue adsorption operation and the activated carbon regeneration operation, the physical properties (surface area, pore volume, pore distribution) of the activated carbon are not limited at all. Activated carbon in the form of granules or pellets which are generally commercially available can be used.

The method of supporting platinum on activated carbon and the metal source are not limited as long as platinum is supported.
Generally, in consideration of the operability, safety, cost, and the effect on activated carbon of the metal supporting method, the impregnation method using a platinum solution (the solvent is not limited to water or an organic solvent) is preferable. Examples of such a platinum solution include platinum complexes such as bisacetylacetonatoplatinum and platinum nitrate [Pt (NO ₃ ) ₄ ).
And a solution of an organic solvent such as an alcohol.

After the operation of supporting platinum, a drying treatment is required. However, if the solvent used to support the platinum on the activated carbon as a carrier is removed, and the adsorbing ability of the residue can be secured to some extent, The method is not limited at all. In addition, the oxidation treatment and the reduction treatment for immobilizing platinum on the activated carbon carrier are not limited to a particular method.

The amount of platinum supported on activated carbon is not limited as long as the adsorbed residue is removed by an oxidation reaction. However, in order to completely remove the residue at a low temperature so as not to affect the activated carbon, it is necessary that a certain amount of platinum is dispersed throughout the activated carbon. On the other hand, if platinum is supported more than necessary, the production cost may increase, and the surface area of activated carbon or the amount of residue adsorbed may be reduced. Therefore, platinum is preferably 0.01 to 5% by mass, more preferably 0.03 to 1% by mass, and more preferably 0.05 to 1% by mass in terms of metal, based on the weight of activated carbon after loading.
0.50% by weight is more preferred. With the loading amount in such a range, the effect of supporting platinum on the residue adsorbing capacity of activated carbon is not recognized.

Activated carbon loaded with platinum has a surface area of 1000 to 2000 m ² / g and a pore volume of 0.1
〜0.3 Ncm ³ / g. By using the platinum-supported activated carbon having such properties, only the residue adsorbed on the activated carbon can be selectively oxidized and removed.

The platinum-supported activated carbon is preferably used by filling it in an adsorption tower. The LP gas is fed into the adsorption tower, and the residue in the LP gas is adsorbed and removed by contact with the adsorbent filled in the adsorption tower. The size and shape of the adsorption tower are not particularly limited.

Activated carbon that has adsorbed a predetermined amount of the residue in the LP gas by contact with the LP gas is regenerated by selectively oxidizing the adsorbed component (residue) with oxygen. The estimated reaction equation at this time is shown in the following equation.

C _n H _{2n + 2} + [(3n + 1) / 2] O ₂ →
n CO ₂ + (n + 1) H ₂ O + ΔQ

When an oxygen mixed gas is used as the regeneration gas, the desorption or decomposition temperature of the adsorbed residue is 350 ° C. or higher, substantially 400 ° C., as in the conventional regeneration gas.
That is all. On the other hand, the combustion start temperature of activated carbon is 45
0-460 ° C. Therefore, regenerating the activated carbon adsorbing the residue with the oxygen mixed gas has a regeneration temperature range of only 50 ° C., and it is difficult to selectively oxidize and remove only the residue.

On the other hand, when the activated carbon carrying platinum is regenerated with an oxygen mixed gas, the combustion start temperature of the activated carbon remains unchanged at 450 to 460 ° C. On the other hand, the adsorbed residue can be completely removed by an oxidation reaction at 200 ° C to 400 ° C. This is considered to be due to the fact that the carried platinum acts as an oxidation catalyst, whereby only the residue can be selectively oxidatively decomposed at a lower temperature.

Before the regeneration treatment of the activated carbon by oxygen oxidation, it is preferable to purge the LP gas remaining in the adsorption tower by adsorbing the activated carbon with an inert gas such as nitrogen and remove it in advance. . By doing so, abnormal combustion and abnormal heat generation during oxygen oxidation can be prevented, and the amount of heat generated in the tower, the amount of regeneration gas, and the output of equipment such as a blower can be suppressed. It is also preferable to recover the LP gas from the purge gas.

Oxygen oxidation is generally performed with an oxygen mixed gas. In addition, since this reaction can be performed in an adsorption tower filled with activated carbon, regeneration by oxygen oxidation can be performed not only off-site but also on-site.

When an oxygen mixed gas is used for oxygen oxidation, the oxygen mixed gas preferably has an oxygen content of 0.01 to 25% by volume in terms of 0 ° C. and 1 atm. It is more preferably 0.1 to 21 (ie, the same oxygen concentration as air) volume% in terms of state. Since the reaction of the formula (1) is an exothermic reaction, if the concentration of oxygen is high, the temperature of the activated carbon becomes locally high. On the other hand, if the oxygen concentration is too low, the regeneration time will be longer than necessary.

The temperature of the oxygen oxidation depends on the oxygen flow rate because the amount of heat generated by the combustion of the activated carbon depends on the oxygen flow rate.
C. is preferred, and a temperature range of 250 to 400 C. is more preferred. By performing at such an oxygen concentration and a regeneration temperature, only the adsorbed residue can be selectively oxidized and removed without causing loss to the activated carbon.

Further, in the present invention, by repeating the step of contacting the activated carbon with the LP gas to remove the residue in the LP gas and the step of selectively oxidizing and removing only the residue adsorbed on the activated carbon, It is possible to continuously remove the residue in the LP gas.

In this regeneration method, no effect is seen on the activated carbon. By the first regeneration treatment, the moisture contained in the activated carbon and the residue on the metal support (the organic component of the organic platinum salt and the counter ion of the inorganic platinum salt) were removed, or the powder component of the activated carbon was removed. A few%, usually 5%
Except for the case where a small amount of weight loss may occur, no physical loss of the activated carbon such as weight loss, residue adsorption capacity, surface area and pore volume is observed at all. That is, it is possible to physically and chemically regenerate the adsorbent at 100%.

[0032]

Next, the present invention will be described in more detail by way of examples. (1) Residue adsorptive capacity evaluation test (i) Using an autoclave or a thermostatic shaker, n-
The equilibrium adsorption capacity and adsorption isotherm by batch adsorption with a hexane or LP gas solution were measured. (ii) An LP gas solution was passed through a fixed bed adsorption tower filled with activated carbon to perform an adsorption removal experiment on residues.

(2) Activated carbon regeneration evaluation test (i) Adsorption capacity evaluation test The thermogravimetric / differential thermal analysis (hereinafter referred to as “T
G / DTA ". ) Was performed.
The residue adsorption amount used as an index was 5 mass % (or 2.5 mass % ), which is the equilibrium adsorption amount when the residue equilibrium concentration was about 8 mass ppm for propane and about 80 mass ppm for butane. This is an assumed value when removing the residue in LP gas (propane gas). Since LP gas has a high pressure at normal temperature, it is liquid at normal temperature and normal pressure, and the residue adsorption treatment was performed with an n-hexane solution that is easier to handle than LP gas.
However, in the n-hexane solution, the residue adsorption amount on the activated carbon is smaller than that of the LP gas. Therefore, the residue adsorption isotherm of each solution was obtained, and the residue concentration was adjusted so that the same residue adsorption amount was obtained. . For example, in the n-hexane solution, the initial concentration before adsorption was slightly higher than 1000 mass ppm, and the concentration of the residue was increased to adsorb the same amount of residue as the propane solution.

(Ii) Adsorption capacity evaluation of the above (1) A regeneration experiment was carried out in a fixed bed adsorption tower previously filled with activated carbon to which the residue had been adsorbed by the method of (i). (iii) An on-site regeneration experiment was performed on a fixed bed adsorption tower of the activated carbon to which the residue was adsorbed by the method of (1) Evaluation of adsorption capacity (ii).

1. Evaluation method of adsorption capacity (1) Measurement method of equilibrium adsorption amount of residue Put a predetermined amount of activated carbon or metal-supported activated carbon in an autoclave, and add propane, butane, containing an arbitrary amount of residue.
100 g of organic solution such as n-hexane per 1 g of activated carbon
After adding m ³ and stirring for 24 hours, the equilibrium adsorption amount was measured by measuring the amount of change in the concentration of the lubricating oil in the solution.

(2) Measurement of breakthrough curve Adsorption tower A (inner diameter 1.5 cm, tower height 70 cm), adsorption tower B (inner diameter 2.5 cm, tower height 70 cm), or adsorption tower C
(An inner diameter of 5.3 cm and a tower height of 150 cm) are filled with an adsorbent, and the lubricating oil concentration is adjusted to a predetermined concentration using propane or butane at a flow linear velocity of 4 to 25 cm / min. The breakthrough curve was measured by measuring the lubricating oil concentration at the tower outlet. The method for measuring the concentration of the lubricating oil is the same as the above method.

2. Evaluation method of regenerative ability (1) Evaluation of regenerative ability of adsorbent by TG / DTA measurement 5 to 10 mg of activated carbon or metal-supported activated carbon to which lubricating oil was adsorbed by the method of (1) above was sampled, and 100 Ncm ^{3 of} air was sampled. / Min, helium 200Ncm ³ / m
In, TG / DTA was measured at a heating rate of 15 ° C./min, and the regeneration ability of the activated carbon was evaluated by comparing the decomposition temperature of the residue and the combustion temperature. The lower the decomposition and combustion temperature of the residue, and the greater the change in weight due to the removal of the residue is the same as the amount of adsorption of the residue, the better the reproducibility is evaluated.

(2) Evaluation of adsorbent regeneration ability by measuring activated carbon regeneration temperature in tower Adsorption tower A (inner diameter 1.5 cm, tower height 70 cm), adsorption tower B (inner diameter 2.5 cm, tower height 70 cm) To the adsorption tower C (inner diameter 5.3 cm, tower height 150 cm) or the adsorption tower D (inner diameter 7.3 cm, tower height 100 cm).
Using the method described above, the residue was previously filled with activated carbon having been adsorbed at a predetermined concentration, and the regeneration was continued at a predetermined regeneration temperature, oxygen concentration, and gas flow until the temperature inside the column did not rise, and then the adsorbent was withdrawn. By the methods (1) and (1) of (1), evaluation of the adsorbing ability and regenerating ability of the adsorbent and measurement of physical properties were performed.
In addition, this step was repeated, and the regenerating ability by repeated regeneration was evaluated.

3. Method for measuring physical properties of adsorbent (1) Method for measuring specific surface area, average pore diameter, pore volume, etc. The porous physical properties of activated carbon and metal-supported activated carbon (hereinafter, referred to as “adsorbent”) (hereinafter, “adsorbent physical properties”) ")
Was measured using a high purity nitrogen (purity of 99.99995% or more) probe molecule with an automatic surface area, pore diameter, and pore volume measuring device (Belsorp 28, manufactured by Bell Japan). In the measurement of physical properties of the adsorbent, specific surface area, pore diameter,
Prior to the measurement of the pore volume, the sample adsorbent was subjected to heat treatment under reduced pressure as a pretreatment, and desired physical properties were measured.

In the heat treatment under reduced pressure of the sample adsorbent, 100 m
g sample in a quartz glass sample tube, 10 ^-1 to 10
While maintaining the reduced pressure of ^-2 mmHg, the heating rate was 6 ° C /
The temperature was raised from room temperature to 350 ° C. in 3 minutes and kept at the same temperature for 3 hours. Then, normal pressure + with high purity helium gas
While maintaining the pressure at 5 mmHg, the temperature was lowered to room temperature at a rate of 5 ° C./min to obtain a sample for measurement. The obtained sample weight was accurately weighed and used for measurement of physical properties of the adsorbent.

In the measurement of the physical properties of the adsorbent, the liquefied nitrogen temperature (−
196 ° C.), the use was measured three or more times with high-purity helium, and after evacuation under reduced pressure, probe molecules (nitrogen) were introduced to perform adsorption and desorption measurement on the sample adsorbent.
The specific surface area, pore volume, and average pore diameter of the adsorbent were calculated based on the measurement results.

Example 1 A granular activated carbon having a surface area of 1535 m ² / g and a pore volume of 0.247 cm ³ / g dried at 110 ° C.
Called "AC". ) 20.0 g with 0.04 g of bis-
It was impregnated with a 200 cm ³ acetone solution of acetylacetonatoplatinum Pt (acac) ₂ for 4 hours. Thereafter, the acetone solvent was removed at reduced pressure at room temperature, and nitrogen purge at room temperature and nitrogen purge at 150 ° C. were performed to dry the platinum-supported activated carbon. Surface area 1533 m ² /
g, 20.2 g of granular platinum-supported activated carbon having a pore volume of 0.246 cm ³ / g. ICP method (Inductively coupled plasma method)
As a result, the amount of supported platinum was 0.11% by mass. Hereinafter, this platinum-supported activated carbon is referred to as Pt / AC-1.

3.00 g of Pt / AC-1 was placed in 300 cm ^{3 of} n-hexane solution (100 cm ³ per 1 g of activated carbon) in which a predetermined amount of lubricating oil was dissolved, and allowed to stand at room temperature with stirring for 24 hours to equilibrate. It was in the adsorption state. After the batch adsorption treatment, the pressure was reduced to remove the n-hexane solvent, and the activated carbon was dried. From the difference in the amount of the residue in the solution, Pt / AC
The residue amount adsorbed on -1 was 2.5% by mass. The concentration of the residue before the adsorption of the n-hexane solution was determined from the adsorption isotherm of the residue of the n-hexane solution.

Investigation of residue removal behavior by TG / DTA
Was. About 5 to 10 mg of Pt / AC-1 with the residue adsorbed
Helium gas 200Ncm^Three/ Min, air 100N
cm^Three/ Min mixed gas, ie about 7% by volume of oxygen
Oxygen mixed gas flow 300Ncm ^Three/ Min at 15 ° C /
The temperature was raised from 30 ° C. to 700 ° C. at a temperature rising rate of min.
FIG. 2 shows the TG / DTA results of Pt / AC-1. 80
N-Hexane or water used as a solvent is removed at
After separation, the residue content peaked at 280 ° C and was 250-400.
It was shown to desorb or oxidatively decompose at ℃. Also,
Above about 460 ° C., a peak attributed to activated carbon appeared.
Weight loss of residue determined by TG / DTA is 2.5
%, Which was the same as the adsorption amount.

Example 2 In the same manner as in Example 1, 20.0 g of activated carbon was added to 0.12
g of bis-acetylacetonato platinum to support platinum, a surface area of 1520 m ² / g, and a pore volume of 0.235 Ncm ³ / g.
g of granular platinum-supported activated carbon (20.2 g) were obtained. The supported amount of platinum determined by the ICP method was 0.30% by mass. Less than,
This platinum-supported activated carbon is designated as PT / AC-2.

The residue adsorption treatment was carried out in the same manner as in Example 1, and 2.4 mass% of the residue was adsorbed on Pt / AC-2. Under the same conditions as in Example 1, TG / DTA was measured. FIG. 2 shows the measurement results. The residue was shown to desorb or oxidatively decompose at 240-400 ° C., peaking at 270 ° C. The peak of activated carbon was about 460 ° C. or higher. The weight loss of the residue determined by TG / DTA was 2.4% by mass, which was the same as the amount of adsorption.

Example 3 In the same manner as in Example 1, 0.20 g of activated carbon was added to 20.0 g of activated carbon.
Of bis-acetylacetonatoplatinum having a surface area of 1582 m ² / g and a pore volume of 0.255 Ncm ³ / g
20.2 g of granular platinum-supported activated carbon was obtained. The supported amount of platinum determined by the ICP method was 0.49% by mass. Hereinafter, this platinum-supported activated carbon is referred to as Pt / AC-3.

The residue adsorption treatment was performed in the same manner as in Example 1 to adsorb 2.5% by mass of the residue on Pt / AC-3. TG / DTA was carried out under the same conditions as in Example 1. FIG. 2 shows the measurement results. The residue was shown to desorb or oxidatively decompose at 240-350 ° C with a peak at 270 ° C. The peak of activated carbon was about 450 ° C. or higher.
The weight loss of the residue determined by TG / DTA was 2.5% by mass, which was the same as the amount of adsorption.

Example 4 In the same manner as in Example 1, 0.41 g of activated carbon was added to 20.0 g of activated carbon.
Supported on platinum of bis-acetylacetonato platinum having a surface area of 1524 m ² / g and a pore volume of 0.250 Ncm ³ / g.
20.5 g of granular platinum-carrying activated carbon was obtained. The amount of supported platinum determined by the ICP method was 1.01% by mass. Hereinafter, this platinum-supported activated carbon is referred to as Pt / AC-4.

The residue adsorption treatment was performed in the same manner as in Example 1, and 2.6 mass% of the residue was adsorbed on Pt / AC-4. TG / DTA was carried out under the same conditions as in Example 1. As in Example 3, the residue peaked at 270 ° C.
It was shown to desorb or oxidatively decompose at 40-350 ° C. The peak of activated carbon was about 460 ° C. or higher. TG
/ Weight loss of residue determined from DTA is 2.6% by mass
And the same as the adsorption amount.

Example 5 In the same manner as in Example 1, 0.032 g of activated carbon was added to 20.0 g of activated carbon.
g of bis-acetylacetonatoplatinum, platinum is supported, surface area is 1554 m ² / g, and pore volume is 0.255 Ncm ³ / g.
Thus, 20.0 g of granular platinum-supported activated carbon was obtained. The supported amount of platinum determined by the ICP method was 0.08% by mass. Less than,
This platinum-supported activated carbon is designated as Pt / AC-5.

The residue adsorption treatment was performed in the same manner as in Example 1 to adsorb 2.5% by mass of the residue to Pt / AC-5. TG / DTA was carried out under the same conditions as in Example 1. FIG. 2 shows the measurement results. The residue was shown to desorb or oxidatively decompose at 240-450 ° C., peaking at 300 ° C. The peak of activated carbon was about 460 ° C. or higher. The weight loss of the residue determined from TG / DTA was 2.
5% by mass, which was the same as the amount of adsorption.

Example 6 In the same manner as in Example 1, 0.02 g of activated carbon was added to 20.0 g of activated carbon.
Supported on platinum of bis-acetylacetonato platinum having a surface area of 1501 m ² / g and a pore volume of 0.236 Ncm ³ / g.
19.9 g of granular platinum-supported activated carbon was obtained. The amount of supported platinum determined by the ICP method was 0.05% by mass. Hereinafter, this platinum-supported activated carbon is referred to as Pt / AC-6.

In the same manner as in Example 1, a residue adsorption treatment was carried out to adsorb 2.5% by mass of the residue on Pt / AC-6. TG / DTA was carried out under the same conditions as in Example 1. The side results are shown in FIG. The residue was shown to desorb or oxidatively decompose at 250-450 ° C. with a peak at 340 ° C. The peak of activated carbon was about 460 ° C. or higher. T
The weight loss of the residue determined from the G / DTA measurement was 2.
4% by mass, which was almost the same as the adsorption amount.

Example 7 100.1 g of the activated carbon of Example 1 dried at 110 ° C.
Platinum nitrate P containing 10.01% by mass of platinum in metal conversion
An aqueous solution obtained by diluting 1.000 g of a t (NO ₃ ) ₄ aqueous solution with 80.0 g of water was added dropwise little by little, and the whole activated carbon was sufficiently moistened and allowed to stand overnight. Thereafter, the platinum-carrying activated carbon was dried by purging with nitrogen in a warm water bath at 40 ° C., and then heated from room temperature to 300 ° C. for 30 minutes under a stream of air.
Baking for 3 hours, the surface area is 1480 m ² /
Thus, 100.6 g of granular platinum-supported activated carbon having a pore volume of 0.233 Ncm ³ / g was obtained. The supported amount of platinum determined by the ICP method was 0.10% by mass. Hereinafter, this platinum-supported activated carbon is referred to as Pt / AC-7.

The residue adsorption treatment was performed in the same manner as in Example 1 to adsorb 2.5% by mass of the residue to Pt / AC-7. This was subjected to TG / DTA under the same conditions as in Example 1, and it was shown that the residue was desorbed or oxidatively decomposed at 260 to 400 ° C with a peak at 310 ° C. The peak of activated carbon was about 460 ° C. or higher. The weight loss of the residue obtained from the TG / DTA measurement was 2.5% by mass, which was the same as the adsorption amount.

Example 8 In the same manner as in Example 7, 20.0 g of activated carbon was converted into metal.
Platinum nitrate Pt containing 10.01% by mass of platinum (NO_Three)_Four
An aqueous solution obtained by diluting 2.000 g of an aqueous solution with 16.0 g of water
With platinum, surface area 1462m^Two/ G, pore volume
0.229Ncm ^Three/ G granular platinum-supported activated carbon 20.8
g was obtained. The amount of supported platinum determined by the ICP method is 0.99
%. Hereinafter, this platinum-supported activated carbon is referred to as Pt / AC
-8.

The residue adsorption treatment was performed in the same manner as in Example 1 to adsorb 2.5% by mass of the residue to PT / AC-8. TG / DTA was carried out under the same conditions as in Example 1. As a result, the residue content peaked at 280 ° C and was 250 to 3
It was shown to desorb or oxidatively decompose at 70 ° C. The peak of activated carbon was about 460 ° C. or higher. TG / DTA
The weight loss of the residue determined from is 2.5% by mass,
It was the same as the adsorption amount.

Example 9 In the same manner as in Example 7, 20.0 g of activated carbon was converted to metal.
Platinum nitrate Pt containing 10.01% by mass of platinum (NO_Three)_Four
An aqueous solution obtained by diluting 6.000 g of an aqueous solution with 16.0 g of water
With platinum, surface area 1455m^Two/ G, pore volume
0.233Ncm ^Three/ G granular platinum-supported activated carbon 21.3
g was obtained. The amount of platinum carried by the ICP method was 3.02
%. Hereinafter, this platinum-supported activated carbon is referred to as Pt / AC
−9.

The residue adsorption treatment was performed in the same manner as in Example 1, and 2.4 mass% of the residue was adsorbed on Pt / AC-9. TG / DTA was carried out under the same conditions as in Example 1. As a result, the residue content peaked at 270 ° C. and was 240 to 3
It was shown to desorb or oxidatively decompose at 70 ° C. The peak of activated carbon was about 460 ° C. or higher. TG / DTA
The weight loss of the residue obtained from the measurement was 2.5% by mass, which was almost the same as the adsorption amount.

Example 10 A residue of 5.20% by mass was adsorbed on 14.80 g of Pt / AC-3 obtained above in the same manner as in Example 1 (mass after adsorption of residue: 15.57 g). Inner diameter 1.5cm, tower height 7
A 0 cm adsorption tower (hereinafter, referred to as “adsorption tower A”) was filled (the height of the packed bed was 20 cm). At normal pressure, flow rate 200N
After the temperature was raised to 280 ° C. under a nitrogen gas flow of cm ³ / min, the first regeneration treatment with an oxygen mixed gas of Pt / AC-3 was started at that temperature with the air flow having a flow rate of 100 Ncm ³ / min. did. Due to the heat generated by the oxidation reaction, the temperature in the tower rose to a maximum of 339 ° C., and the point in time when the temperature at the terminal end on the outlet side of the activated carbon packed portion dropped to 280 ° C. was regarded as the end of regeneration. Subsequently, the flow rate was changed to a nitrogen gas flow at a flow rate of 200 Ncm ³ / min, and the tower temperature was lowered to room temperature. The time required for regeneration with the oxygen mixed gas (air) was 1.5 hours, and the weight of the activated carbon after the first regeneration treatment was 13.70 g.

Then, to 13.70 g of the activated carbon,
The residue of 5.00% by mass was adsorbed in the same manner as in Example 1, filled in the adsorption tower A, and subjected to the second regeneration treatment with the oxygen-containing gas in the same manner as the first regeneration treatment. The maximum temperature during the regeneration process is 338 ° C and the regeneration time is 1.5
Time, the weight of activated carbon after the second regeneration treatment is 13.56
g.

The Pt / AC-3 regeneration process described above was repeatedly performed six times while changing the flow rate of air as the regeneration gas. Table 1 summarizes the results.

[0064]

[Table 1]

The weight loss after the first regeneration process is Pt /
This was because water, n-hexane, and a counter ion of platinum salt (acetylacetonate in Example 10) contained in AC-3 were eliminated. At other times of regeneration, there was no significant change in weight or residue adsorption amount.

Example 11 To 750.0 g of Pt / AC-1 obtained above, Example 1 was added.
A residue of 5.00% by mass is adsorbed by the same method as described above (the weight after adsorption of the residue is 783.2 g), and an adsorption tower having an inner diameter of 7.3 cm and a tower height of 100 cm (hereinafter, referred to as “adsorption tower B”).
(Filled layer height 40 cm). After the temperature was raised to 280 ° C. under a nitrogen stream at a flow rate of 15 Nl / min under normal pressure, an oxygen mixed gas having an oxygen concentration of 1.0% by volume and a flow rate of 8.0 Nl / min was changed at that temperature under normal pressure. Pt / A
The first regeneration process with the oxygen mixed gas of C-1 was started. Due to the heat generated by the oxidation reaction, the temperature in the tower rose to 360 ° C. The temperature in the tower of 360 ° C is 20 cm from the inlet side.
, The regeneration gas pressure from normal pressure to 0.3 MPa, when reaching 30 cm,
MPa. Even when the pressure was increased, the temperature in the column remained at approximately 360 ° C. When the temperature at the end of the activated carbon filling section on the outlet side has dropped to 280 ° C., the regeneration is terminated, and the nitrogen gas flow at a flow rate of 15 Nl / min is changed under normal pressure.
The tower temperature was lowered to room temperature. The activated carbon weight after the first regeneration treatment was 685.2 g.

To 685.2 g of the activated carbon in total,
The residue of 5.05% by mass was adsorbed in the same manner as described above, filled in the adsorption tower B, and subjected to the second regeneration treatment with the oxygen mixed gas by the same operation as the first regeneration treatment. The regeneration conditions were as follows: the oxygen concentration of the oxygen mixed gas was 2% by volume,
min, and the pressure is 0 to 20 cm at normal pressure, activated pressure is 0.3 MPa for ３０30 cm, and 0.5 M for ４０40 cm.
Regeneration was performed at Pa. The temperature in the tower during the regeneration treatment fluctuated at about 380 ° C. regardless of the pressure. The activated carbon weight after the second regeneration treatment was 690.3 g.

To the total amount of 690.3 g of the activated carbon,
The residue of 5.05% by mass was adsorbed by the same method as described above, packed into the adsorption tower B, and subjected to the third regeneration treatment with the oxygen mixed gas by the same operation as the first regeneration treatment. The regeneration conditions were such that the oxygen concentration of the oxygen mixed gas was 0.8% by volume and the flow rate was 25.0.
Nl / min was set, and the pressure was all regenerated at normal pressure. The temperature in the tower during the regeneration treatment fluctuated at approximately 340 ° C. The activated carbon weight after the third regeneration treatment was 695.1 g.

To 695.1 g of the activated carbon in total,
A residue of 4.99% by mass was adsorbed in the same manner as in the above, filled in the adsorption tower B, and subjected to the fourth regeneration treatment with an oxygen mixed gas by the same operation as the first regeneration treatment. The regeneration conditions were as follows: the oxygen concentration of the oxygen mixed gas was 2% by volume, the pressure was normal pressure, and the flow rate was 6.0 Nl / mi for the activated carbon filled portion of 0 to 20 cm.
For n and ４０40 cm, reproduction was performed at 8.0 Nl / min.
The temperature in the tower during the regeneration treatment varied depending on the flow rate, and was changed at 380 ° C and 420 ° C, respectively. The activated carbon weight after the fourth regeneration treatment was 694.8 g.

The weight loss after the first regeneration process is Pt /
This was because the water, n-hexane, and the counter ion of the platinum salt (acetylacetonate in Example 11) contained in AC-1 were eliminated. At other times of regeneration, there was no significant change in weight or residue adsorption amount.

Example 12 31.60 g of the previously obtained Pt / AC-1 was adsorbed on the adsorption tower A.
(Filled bed height 40 cm), normal pressure, room temperature, flow rate 3
The inside of the adsorption tower was purged with 0.0Nl / h of nitrogen for 3 hours.
Then, after sufficiently replacing the inside of the tower with LP gas containing no residue, LP gas containing 90 ppm of residue was added to the column.
The liquid was passed in the upstream direction at a flow rate of 0 cm ³ / min for 20 hours, and the first residue removal treatment in the LP gas was performed. The outlet concentration of the residue was measured, and FIG. 3 shows the change over time, that is, a breakthrough curve. Outlet concentration / inlet concentration of residue is 10
% Breakthrough time was 13.1 hours.

After the residue removal treatment, the temperature was raised from room temperature to 250 ° C. while flowing nitrogen at a flow rate of 30.0 Nl / h under normal pressure in the downstream direction to remove LP gas in the adsorption tower. Subsequently, at 250 ° C. under normal pressure, the oxygen concentration was 1% by volume, and the flow rate was 3
Switching to an oxygen mixed gas of 0.0Nl / h was performed to start the Pt / AC-1 regeneration process using the oxygen mixed gas. Due to the heat generated by the oxidation reaction, the temperature inside the tower rises to a maximum of 304 ° C, and the temperature at the end of the outlet of the activated carbon filling section becomes 250 ° C.
The point in time at which the playback time has decreased is regarded as the end of playback. Continue to flow 3
The nitrogen stream was switched to 0.0Nl / h, and the temperature of the adsorption tower was lowered to room temperature.

With the activated carbon filled in the adsorption tower, a second residue removal treatment of the LP gas is performed again under the same LP gas conditions as described above, and the breakthrough curve is shown in FIG. The breakthrough time was 13.0 hours, showing the same residue adsorption capacity as the first time.

Comparative Example 1 Residue adsorption treatment was performed in the same manner as in Example 1 to adsorb 2.5% by mass of the residue on activated carbon. Under the same conditions as in Example 1, TG / DTA was measured. as a result,
The residue was shown to desorb at 350-450 ° C with a peak at 390 ° C. The peak of activated carbon was about 460 ° C. or higher. The weight loss of the residue determined from the TG / DTA measurement was 1.4% by mass, which was smaller than the adsorption amount, and the residue could not be completely removed.

Comparative Example 2 Residue adsorption treatment was performed in the same manner as in Example 1, and Pt /
AC-3 was allowed to adsorb 2.5% by mass of the residue. This is converted to a helium gas, that is, a gas flow of 300N with oxygen at 0% by volume.
30 ° C. at a rate of 15 ° C./min at a rate of cm ³ / min
TG / DTA was measured under conditions of elevated temperature from 700 ° C. to 700 ° C.
As a result, the residue content peaked at 400 ° C. and was 350 to 450
It was shown to desorb at ° C. The peak of activated carbon is about 46
It was 0 ° C or higher. The weight loss of the residue obtained from the TG / DTA measurement was 1.5% by mass, which was smaller than the adsorption amount.
The residue could not be completely removed.

Comparative Example 3 In the same manner as in Example 1, 20.0 g of activated carbon was added to 0.002
g of bis-acetylacetonatoplatinum, platinum is supported, surface area is 1548 m ² / g, and pore volume is 0.257 Ncm ³ / g.
Thus, 20.0 g of granular platinum-supported activated carbon was obtained. The supported amount of platinum determined by the ICP method was 0.005% by mass. Hereinafter, this platinum-supported activated carbon is referred to as Pt / AC-10.

The residue adsorption treatment was performed in the same manner as in Example 1 to adsorb 2.5% by mass of the residue on Pt / AC-10. Under the same conditions as in Example 1, TG / DTA was measured. As a result, the residue content peaked at 350 ° C and was 2
It was shown to desorb or oxidatively decompose at 50-450 ° C. The peak of activated carbon was about 460 ° C. or higher. TG
/ The weight loss of the residue obtained from the measurement of DTA is 2.0
% By mass, less than the adsorption amount, and the residue could not be completely removed.

Comparative Example 4 In the same manner as in Example 1, 2.80 g of activated carbon was added to 20.0 g of activated carbon.
Supported on platinum of bis-acetylacetonato platinum having a surface area of 1280 m ² / g and a pore volume of 0.204 Ncm ³ / g.
Was obtained in an amount of 21.9 g. The supported amount of platinum determined by the ICP method was 6.40% by mass. Hereinafter, this platinum-supported activated carbon is referred to as Pt / AC-11.

The residue adsorption treatment was performed in the same manner as in Example 1, and Pt / AC-11 adsorbed 2.1% by mass of the residue. Under the same conditions as in Example 1, TG / DTA was measured. As in Example 3, the residue was shown to desorb or oxidatively decompose at 220-330 ° C. with a peak at 270 ° C. The peak of activated carbon was about 460 ° C. or higher. The weight loss of the residue determined from TG / DTA was 2.
1 mass%, which was the same as the amount of adsorption. At this time, the residue was completely removed, but since the amount of supported platinum was too large, the surface area and the pore volume were reduced, and the residue adsorption was also reduced.

Comparative Example 5 In the same manner as in Example 1, the activated carbon 15.0 described in Example 1 was used.
After adsorbing 5.00% by mass of the residue in 0 g, the mixture was charged into the adsorption tower A, and the pressure inside the tower was reduced to 1.3 kPa (1 kPa) using a vacuum pump.
The temperature was raised to 250 ° C. while reducing the pressure to 0 Torr.
Thereafter, the temperature was kept at 1.3 kPa and 250 ° C. for 4 hours. The activated carbon weight after the regeneration treatment was 14.61 g. The activated carbon after the regeneration treatment was again subjected to the residue adsorption treatment, and the adsorption amount was 1.02% by mass.

Comparative Example 6 In the same manner as in Example 1, activated carbon 15.0 described in Example 1
After adsorbing 5.06% by mass of the residue to 0 g, the mixture was charged into the adsorption tower A, and the pressure in the tower was reduced to 1.3 kPa by a vacuum pump.
The temperature was increased to 400 ° C. while reducing the pressure to (10 Torr). Thereafter, it was kept at 1.3 kPa and 400 ° C. for 4 hours. The activated carbon weight after the regeneration treatment was 14.33 g. The activated carbon after the regeneration treatment was again subjected to the residue adsorption treatment, and the adsorption amount was 2.97% by mass.

Comparative Example 7 In the same manner as in Example 1, activated carbon 15.0 described in Example 1
After adsorbing 5.06% by mass of the residue to 0 g, the mixture was packed in the adsorption tower A, heated to 250 ° C. under a nitrogen flow at a flow rate of 200 Ncm ³ / min, and then heated at a flow rate of 100 Ncm ³ / min.
250 ° C. instead of Ncm ³ / min steam purge
For 4 hours. The activated carbon weight after this regeneration treatment is 1
The weight was 4.70 g. The activated carbon after the regeneration treatment was again subjected to the residue adsorption treatment, and the adsorption amount was 0.68% by mass.

Comparative Example 8 The same regenerating operation as in Example 10 was performed while changing the regenerating temperature. A residue of 5.18% by mass was adsorbed on 14.90 g of Pt / AC-3 in the same manner as in Example 1, and packed into adsorption tower A. The temperature was raised to 180 ° C. under a nitrogen flow at a flow rate of 200 Ncm ³ / min. Then, at that temperature, a flow rate of 10
The regeneration treatment with an oxygen mixed gas was started in place of the air flow of 0 Ncm ³ / min. The maximum temperature in the tower is 187 ° C
However, since the temperature rise was small and it was not clear when the temperature at the end portion on the outlet side of the activated carbon filling portion dropped to 180 ° C. to end regeneration was unclear, the first regeneration process of Example 10 was performed. 1.5 hours, the same as the time. After the regeneration treatment, the flow rate was changed to a nitrogen flow at a flow rate of 200 Ncm ³ / min.
The tower temperature was lowered to room temperature. The weight of the activated carbon after the regeneration treatment was 14.80 g. The residue was adsorbed on the entire amount of 14.80 g of this activated carbon in the same manner as in Example 1, but the residue adsorbed amount was only 0.20% by mass.

Comparative Example 9 The same regenerating operation as in Example 10 was performed while changing the regenerating temperature. A residue of 5.10% by mass was adsorbed on 14.90 g of Pt / AC-3 in the same manner as in Example 1, and packed into the adsorption tower A. After the temperature was raised to 360 ° C. under a nitrogen flow at a flow rate of 200 Ncm ³ / min, the flow rate was 200 Nc at that temperature.
The regeneration treatment with an oxygen mixed gas was started in place of the air flow of m ³ / min. The temperature in the column rises to a maximum of 493 ° C., and the temperature at the end of the outlet side of the activated carbon packing section becomes 360 °.
The point at which the temperature dropped to ℃ was regarded as the end of regeneration. Flow rate 200Nc
The tower temperature was lowered to room temperature by changing to a nitrogen stream of m ³ / min. The time required for regeneration with oxygen mixed gas (air) is 0.9
In time, the activated carbon after the regeneration treatment weighed 12.56 g. The surface area of Pt / AC-3 after the regeneration treatment is 1250
m ² / g, and the pore volume was 0.183 cm ³ / g.
The weight and physical properties of the activated carbon were greatly reduced as compared with those before the regeneration treatment.

Comparative Example 10 Activated carbon 694.8 g after the fourth regeneration treatment of Example 11
A residue of 5.10% by mass was adsorbed on the entire amount in the same manner as in Example 1, packed in the adsorption tower B, and subjected to a regeneration treatment with an oxygen mixed gas in the same operation as the first regeneration treatment. The regeneration conditions were as follows: the oxygen concentration of the oxygen mixed gas was 2% by volume, the pressure was normal pressure, and the flow rate was 10.0% for the activated carbon filled portion 0 to 20 cm.
Reproduction was performed at 12.0 Nl / min for Nl / min and ４０40 cm. The temperature in the tower during the regeneration treatment varied depending on the flow rate, and was about 460 ° C. and about 500 ° C., respectively. 5
The activated carbon weight after the second regeneration treatment was 670.7 g. The surface area of Pt / AC-1 after the regeneration treatment is 1150 m
^The pore volume was 0.156 cm ³ / g. The weight and physical properties of the activated carbon were greatly reduced as compared with those before the regeneration treatment.

Comparative Example 11 The adsorption tower A was filled with 33.64 g of activated carbon (having a packed bed height of 40).
cm) under the same LP gas and processing conditions as in Example 12.
A second residue removal process in the LP gas was performed. Breakthrough time was 13.0 hours. FIG. 3 shows a breakthrough curve. A regeneration process using an oxygen mixed gas after the residue removal process was performed in the same manner as in Example 12. The temperature in the adsorption tower during the regeneration treatment was 260 ° C. at the maximum. Further, the second residue removal treatment in the LP gas was performed under the same LP gas conditions as described above, but the breakthrough time was 7.8 hours, and the residue adsorption ability was lower than the first time.

[0087]

As described above, according to the present invention, there is provided a method for removing residues in a liquefied gas using an adsorbent (activated carbon carrying platinum) which can be regenerated at a lower temperature than in the past, and the adsorbent Is provided. Further, according to the present invention, the removal of the residue in the liquefied gas and the regeneration of the adsorbent can be repeated, and the residue in the liquefied gas can be continuously removed.

[Brief description of the drawings]

FIG. 1 shows a liquefied petroleum gas (LP) for carrying out the present invention.
This is an example of an apparatus that can continuously remove the residue in G) and regenerate the adsorbent.

FIG. 2 is a TG of Pt / AC of Examples 1, 2, 3, 5, and 6
It is a chart figure of the experimental result (measurement result) of / DTA.
In the figure, the horizontal axis represents temperature (° C.), and the vertical axis represents DTG.

FIG. 3 is a graph showing breakthrough curves of the first and second Pt / AC residue removal effects of Example 12 and Comparative Example 11. In the figure, the abscissa indicates the flow time (h) of the liquefied petroleum gas, and the ordinate indicates the concentration (outlet concentration) of the residue in the liquefied petroleum gas subjected to the adsorption treatment. The percentage (%) obtained by dividing by the concentration of the residue is shown.

[Explanation of symbols]

 1a, 1b adsorption tower

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yukinori Hataya 3-28-15 Higashi-Osawa, Koshigaya, Saitama Prefecture (72) Inventor Katsuhiro Kato 1134-2, Gongendo, Satte City, Saitama Prefecture (72) Inventor Yutaka Miyata Koshigaya, Saitama Prefecture 830-3 Kuri, Shimouma, Ichimi (72) Inventor 5-1 Shoizumi Drive Hillside Drive St. Catharines, Ontario Canada L2T 3N8 F Term (Reference) 4D017 AA04 BA06 CA03 CA06 CB01 DA01 DB03 EA01 EA03 EB07 4G046 HC11 HC15 4G066 AA05B AA28B AA53A BA25 BA26 BA36 CA51 DA09 DA20 GA32 FA

Claims (6)

[Claims] 1. A method for removing a residue in a liquefied gas, wherein the residue is adsorbed to the activated carbon by contacting the liquefied gas with a packed bed filled with activated carbon carrying platinum. Method for removing residues in liquefied gas. 2. The liquefied gas is brought into contact with a packed bed filled with activated carbon loaded with platinum, whereby the residue is adsorbed on the activated carbon, and the residue adsorbed on the activated carbon is oxidized with oxygen, A method for regenerating an adsorbent, comprising regenerating activated carbon. 3. A step of removing a residue in the liquefied gas, wherein the residue in the liquefied gas is adsorbed on the activated carbon by bringing the liquefied gas into contact with a packed bed filled with activated carbon carrying platinum. By oxidizing the residue in the liquefied gas adsorbed on the activated carbon with oxygen, to have the activated carbon regenerating step of regenerating the activated carbon, and continuously and repeatedly performing these steps. Minute removal method. 4. The residue in a liquefied gas according to claim 1, wherein activated carbon in which platinum is supported in an amount of 0.01 to 5% by mass in terms of metal based on the weight of the activated carbon after being supported is used. Minute removal method. 5. The method for regenerating activated carbon according to claim 2, wherein activated carbon loaded with 0.01 to 5% by mass of platinum in terms of metal, based on the weight of activated carbon after loading, is used as an adsorbent. . 6. The oxygen oxidation is carried out in a temperature range of 200 to 450 ° C. using a mixed gas having an oxygen content of 0.01 to 25% by volume in terms of a standard state at 0 ° C. and 1 atm. The method for regenerating activated carbon according to claim 2 or 5, wherein the method is performed.