JPH06104195B2 - Liquid-phase hydrocarbon dissolved gas adsorbent - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Field of Industrial Application The present invention relates to dissolved carbon monoxide (hereinafter abbreviated as dissolved CO) and / or dissolved oxygen (hereinafter dissolved) in liquid-phase hydrocarbons.
Abbreviated as O ₂ . ) Is removed.

Conventionally, the removal of trace amounts of dissolved CO and dissolved O ₂ in liquid-phase hydrocarbons has been carried out by distillation, adsorption removal with molecular sieves, etc.
There is a disadvantage that the O ₂ concentration is not always efficient if it is set to 0.1 ppm or less.

The present invention provides an adsorbent that removes dissolved CO and dissolved O ₂ in liquid-phase hydrocarbons, has a high efficiency of removing dissolved CO and dissolved O ₂ , and has a large adsorption amount, and is sufficient even in the liquid phase. It is an extremely effective adsorbent in the industry, which has characteristics such as high crush strength.

(2) Conventional technology For example, molecular sieve 4A or 5A is used as a method for removing a trace amount of dissolved CO or dissolved O ₂ (concentration of 5 ppm or less) contained in liquefied propylene, liquefied butadiene or C ₄ fraction. Some of them are used for adsorption removal. With this method, the adsorption amount of molecular sieves is small,
There is also a drawback that the adsorption speed is slow. Alternatively, a catalyst with high oxidation activity, such as Cu-Mn called hopkite
There is an attempt to remove dissolved CO and dissolved O ₂ at the same time by using a system oxide, but the activity in the liquid phase is low and it is not practical.

There are also attempts to remove dissolved CO and dissolved O ₂ in the liquefied gas by distillation, but since they are of low concentration,
It is inefficient and not a practical method. Conventional adsorbents are inadequate in terms of performance, cannot be applied as adsorbents in the liquid phase, have a large amount of dissolved CO and dissolved O ₂ adsorbed, and are highly resistant to use in the liquid phase. The development of high performance adsorbents is desired.

(3) Problem to be Solved by the Invention Therefore, the present invention does not have the above-mentioned problems, and is a high-performance adsorbent that efficiently adsorbs and removes a small amount of dissolved CO and dissolved O ₂ in a liquid-phase hydrocarbon under a liquid phase. The purpose is to provide.

(4) Means for Solving the Problems An object of the present invention is to use an adsorbent in which salts or oxides of adsorbed palladium and lead are supported on a carrier as an adsorbent, and to dissolve the hydrocarbon in a hydrocarbon under liquid phase conditions. This is achieved by adsorbing and removing CO and dissolved O ₂ .

(5) Action Coordinating anionic polymerization catalysts for producing polyolefins include transition metal compounds such as titanium tetrachloride, titanium trichloride, vanadium oxychloride, and organometallic compounds such as triethylaluminum, triisobutylaluminum, and diethylaluminum. Although it was a binary catalyst composed of an alkylaluminum compound, recently, a complicated catalyst system to which various third components are added and a supported catalyst supporting the above-mentioned transition metal compound have been developed. In particular, as a catalyst for polypropylene, a combination of titanium trichloride obtained by reducing titanium tetrachloride with aluminum and diethylaluminum chloride has been mainly used.
A highly stereoregular catalyst such as titanium trichloride obtained by reducing a third component catalyst containing a stereoregularity improver or titanium tetrachloride with a complexing agent together with a complexing agent, and titanium trichloride supported on magnesium chloride. Highly active catalyst systems based on the combination of triethylaluminum and electron donors are becoming available.

As the performance of catalysts for producing polyolefins has been improved, the allowable amount of catalyst poisoning substances contained in the raw material olefins such as dissolved CO and dissolved O ₂ has been controlled extremely strictly. .

The present invention can be used particularly for adsorbing and removing a trace amount of dissolved CO and dissolved O ₂ in a liquid phase hydrocarbon having 3 to 6 carbon atoms.

The hydrocarbon is not particularly limited, but may be any of paraffinic hydrocarbon, olefinic hydrocarbon, alicyclic hydrocarbon and the like. Further, it may be a single compound or a mixture of various hydrocarbons.

In particular, it can be suitably used for the adsorption removal of a trace amount of dissolved CO and dissolved O ₂ in olefinic hydrocarbons such as propylene, butene, butane, butadiene, and hexene.

The dissolved CO and dissolved O ₂ concentrations in the raw material hydrocarbon are preferably 10 ppm or less, and more preferably 5 ppm or less. If the raw material contains 10 ppm or more of dissolved CO and dissolved O _2, it is desirable to reduce the concentration to 10 ppm or less by another method in advance.

As the carrier of the adsorbent of the present invention, various known ones such as various metal oxides, activated carbon, silicon carbide and the like can be used, but alumina is particularly preferable, especially γ-Al ₂ O ₃ ,
Those having a large specific surface area with a well-developed pore structure, such as η-Al ₂ O ₃ and θ-Al ₂ O _3, are suitable.

The loading ratio of palladium (Pd) on the carrier as the adsorbent composition is 0.05 to 5% by weight, preferably 0.1 to 2% by weight, and the ratio of lead (Pb) to Pd is 0.1 as the Pb / Pd atomic ratio.
It is in the range of -10, preferably 0.5-8.

When preparing the adsorbent, as the Pd raw material salt, palladium chloride, palladium nitrate, palladium acetate, sodium palladium chloride and the like, as the Pb raw material salt, lead chloride, lead nitrate,
Lead acetate, lead carbonate and the like can be used, but in any case, salts soluble in acid or water can be preferably used. Lead oxide is also effective as a lead compound, but in the case of oxides,
It is preferable that the carrier is used after being impregnated with lead salts and then oxidized by air calcination. Among the lead salts, lead acetate can be most preferably used.

The method for preparing the adsorbent is not particularly limited, and a method usually used for this kind of adsorbent can be appropriately used. As an example, it can be prepared by the following method.
That is, a carrier alumina is impregnated with a predetermined amount of an acid or an aqueous solution of a palladium salt, and the palladium salt is reduced to metallic palladium by a dry method using hydrogen or a wet method using an aqueous solution of hydrazine, formaldehyde and sodium formate. next,
By impregnating the reduced catalyst with a predetermined amount of an aqueous solution of lead salt,
A desired catalyst can be obtained by carrying the lead salt and then drying.

As a route for removing trace amounts of dissolved CO and dissolved O ₂ in hydrocarbons using the adsorbent of the present invention, metal palladium / lead salt /
It is presumed that the adsorption and removal by the complex is mainly due to the combination of the carriers, but it is presumed that the adsorbed palladium supported on the carrier with good dispersibility has an action of oxidizing a part of the dissolved CO metalized. The adsorbent of the present invention is considered to have high performance because the metal and the oxidation reaction proceed simultaneously.

The shape of the adsorbent of the present invention is not particularly limited, but powdery,
In addition to the granular shape, it may be molded into a cylindrical shape, a cylindrical shape, a disk shape, or the like. Generally, a molded product molded into a sphere, a cylinder or a disc having a diameter of about 1 to 30 mm is used.

Normally, when an adsorbent is used in the liquid phase, it is dissolved in hydrocarbons.
When CO and dissolved O ₂ are adsorbed, it is desirable that the particle size of the adsorbent be as small as possible because diffusion to the adsorbent surface cannot be ignored.

The operating temperature of the adsorbent in the liquid phase is usually in the range of 0 to 100 ° C, preferably 5 to 50 ° C. That is, it can be arbitrarily selected within the range in which the hydrocarbon can maintain the liquid phase. However, if the treatment temperature is too low, the removal efficiency will be poor, and if it is too high, the pressure will be high, which is disadvantageous in operation.

The contact time depends on the dissolved CO, dissolved O ₂ concentration in the raw material hydrocarbon, the processing temperature, etc.
A range of ⁰ hr ^-1 is preferred.

The pressure during the treatment is preferably in the range of normal pressure to 50 atm.

The method of contacting the hydrocarbon with the adsorbent can be any method, and it is also possible to add the adsorbent to the hydrocarbon, stir it, and then separate it. Alternatively, the treatment can be carried out by passing hydrocarbon through a tower-shaped body or a tank-shaped body filled with an adsorbent.

Industrially, it is advantageous to use a fixed bed method of the adsorbent and to flow hydrocarbons through the packed bed in an ascending or descending flow.
Further, it is preferable that the adsorption tower is a double tower type and is continuously operated by a switching type.

Next, the present invention will be described in more detail with reference to Examples.

(6) was prepared Example Example _{1 Pd-Pb (CH 3 COO} ) 2 -Al 2 O 3 adsorbent as follows.

After dissolving 0.44 g of palladium chloride in dilute hydrochloric acid, the particle size is 2 to 4 mmφ
Was impregnated with 75 g of γ-Al ₂ O ₃ to absorb the whole amount of the catalyst solution. 80
% Of hydrazine hydrate and 200 ml of 1N-NaOH aqueous solution are mixed to reduce the catalyst. Rinse the reduction catalyst with pure water until Cl ions are no longer detected, then
Dry at 100 ° C for 16 hours.

Lead acetate, Pb (CH ₃ COO), 3H ₂ O, 3.8 g is dissolved in pure water, impregnated with the dry catalyst, and lead acetate is supported. 110 ° C
Dry for 20 hours. The composition of this adsorbent is Pd 0.35 wt%, Pb
The atomic ratio of / Pd is 4.

Using this adsorbent, a removal test of dissolved CO and dissolved O _{2 in} the C ₄ fraction was conducted by the following batch system.

Adsorption conditions Temperature; normal temperature Pressure; autogenous pressure C ₄ cut composition; 1,3-butadiene 42.5 [wt%] isobutene 26.8 butene 28.2 is the main component.

Dissolved CO, dissolved CO concentration; 100-200wtppm C ₄ Distillate amount; 200ml Adsorbent usage amount; 0.5-1g Particle size; 0.5-1mmφ Adsorption time: Approx. 50 hours Test is adsorbent and C _{4 in} 300ml pressure resistant container Dissolved CO and dissolved O ₂ were adsorbed while the fraction was charged and stirred. The analysis was performed by gas chromatography. Dissolved CO, dissolved
The amount of O ₂ adsorbed was 10 mg and 8 mg per g of the adsorbent.

Example 2 Using the adsorbent of Example 1, dissolved C in liquefied propylene
O and dissolved O ₂ were adsorbed. The different adsorption conditions are shown below.

Pressure; 10 atm Propylene composition; Propylene 95.8 [wt%] Propane 4.0 Methane 60wtppm Dissolved CO and dissolved O ₂ adsorption amount is 11 mg and 9 mg per g of adsorbent
Met.

Example 3 Adsorbent Pd- (CH ₃ COO) _{2 was} prepared in the same manner as in Example 1 except that 1.25 g of palladium chloride, 10.7 g of lead acetate and 75 g of γ-Al ₂ O ₃ were used.
-Al ₂ O ₃ was prepared. Pd loading rate 1.0 wt%, Pb / Pd atomic ratio 4
Is. Using this adsorbent, the adsorbed amounts of dissolved CO and dissolved O _{2 in} the liquefied propylene were examined as in Example 4. Dissolved CO,
The amount of dissolved O ₂ adsorbed was 13 mg and 10 mg per g of the adsorbent.

Example 4 Using the adsorbent shown in Example 1, a flow removal test of dissolved CO and dissolved O ₂ in liquefied propylene was conducted under the following conditions.

i) Liquefied propylene composition [wt%] Propylene 95.8 Propane 4.0 Methane 0.007 Others 0.193 ii) Dissolved component concentration Dissolved CO 0.7wtppm Dissolved O ₂ 3.8wtppm iii) Adsorption condition After filling, liquefied propylene was circulated from below.

Temperature ； 40 ℃ Pressure ； 41atm LHSV ； 2hr ^-1 Propylene flow rate ； 4l / hr Under this condition, liquefied propylene was circulated for 20 days and adsorption test was conducted. Both dissolved CO and dissolved O ₂ in outlet propylene were tested. It was below the detection limit.

Comparative Example 1 Using the commercially available room temperature CO adsorbent Hopcalite (Cu-Mn-Oxide) Nissan Gardler Catalyst Co., Ltd., N-140 in the same manner as in Example 2, dissolved CO in liquefied propylene, dissolved
An O ₂ removal test was conducted. Almost no dissolved CO or dissolved O ₂ could be removed.

(7) Effect of the Invention With the adsorbent of the present invention, a trace amount of dissolved CO and dissolved O ₂ in hydrocarbon can be efficiently adsorbed and removed under liquid phase conditions.

Claims (1)

[Claims] 1. Dissolved carbon monoxide and / or dissolved oxygen in liquid-phase hydrocarbons is characterized by using an adsorbent having salts or oxides of metallic palladium and lead supported on a carrier. Gas adsorbent.