JPH0762138B2 - Method for removing arsenic compounds in liquid hydrocarbons - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing arsenic compounds in liquid hydrocarbon containing arsenic compounds. Naphtha is used as a raw material for ethylene and reformers, but in recent years, in order to diversify the raw material, there is an active trend to use natural gas condensate (NGL), which is recovered from natural gas, as a raw material instead of naphtha. But N
Liquid hydrocarbons such as GL contain more than 100 ppb of arsenic, depending on the place of production, and when such liquid hydrocarbons are used as petrochemical raw materials, precious metals (Pt,
(Pd, etc.) system causes deterioration of the catalyst.

[0002]

2. Description of the Related Art Many methods for removing arsenic in gas or liquid have been put into practical use. Arsenic in the solution is dolomite, Ca, Al,
Method to remove by adsorbing to hydroxide such as Mg, Fe, Ba,
There is an extraction method using an organic solvent. These are targeted for arsenous acid and ionic arsenic compounds. Arsenic in gas is adsorbed on activated carbon for arsine (AsH ₃ ) or oxidized by CuO. In the method for removing arsenic compounds in hydrocarbons such as petroleum fractions, activated carbon, basic compounds, 3
The contact treatment with a primary nitrogen compound, an acid, iron, a mercapto compound, or an oxide of copper or manganese is mainly used. In the case of liquid phase treatment, arsenic hydrides or organic arsenic compounds in hydrocarbons are removed from tens of ppb to 10 ppb or less by physical adsorption as described above or oxidation treatment with air or peroxide. However, up to 5 ppb, there is no example of removing up to 5 ppb or less.

Japanese Patent Laid-Open No. 2-248493 discloses a method of removing mercury and optionally arsenic in hydrocarbons by mixing a mixture of a raw material and hydrogen with nickel, cobalt, iron,
Contacting with an arsenic scavenger having "catalytic" properties including at least one metal in palladium and platinum and at least one metal in chromium, molybdenum, tungsten and uranium, then in copper, iron and silver The method of contacting with sulfide or sulfur of at least one metal is proposed, but this method requires a hydrogen-rich gas and the temperature of contacting with the catalyst is 180 to 450 ° C.
It is a fairly high temperature, and it is a hydrodemetallation reaction that converts arsenic into a reactive compound and collects it. This method is economically disadvantageous. Therefore, a method that can remove arsenic in the absence of hydrogen and at a relatively low temperature is desired.

[0004]

An object of the present invention is to provide a method for efficiently removing arsenic compounds in liquid hydrocarbons in the absence of hydrogen and at a relatively low temperature.

[0005]

A method for removing an arsenic compound from a liquid hydrocarbon according to the present invention is a method for removing a liquid hydrocarbon containing an arsenic compound from an adsorbent containing a sulfide of molybdenum in the absence of hydrogen. It is characterized by making contact with.

As the arsenic compound present in the liquid hydrocarbon, arsenic hydride (arsine) or its hydrogen is C ₁ -C.
Examples thereof include an arsine compound substituted with a lower alkyl group of ₄ or 1 to 3 phenyl groups, or an arsenic compound containing halogen or oxygen.

Molybdenum sulfide has an extremely high arsenic compound adsorption activity, but in order to further improve the arsenic compound adsorption effect by molybdenum sulfide, it should be combined with cobalt and / or nickel as a composite sulfide. It is effective to use. When cobalt and / or nickel sulfides molybdenum oxide, it starts sulfide at a lower temperature, and at the same time, cobalt and / or nickel is incorporated into the molybdenum sulfide crystal to prevent its sintering. As a result, it is possible to obtain a highly dispersed sulfide. The content of cobalt and / or nickel is 0.05 to 0.9 atom, preferably 0.1 to 0.8 atom per 1 atom of molybdenum. When the atomic ratio is 0.05 or less, the effect of dispersion is small, while 0.
Even if it is increased to 9 or more, the effect does not increase so much.

Although these metal sulfides can be used as they are as an adsorbent, when the adsorbent is used by being supported on a carrier, the dispersity of the adsorbent is improved and not only the adsorption amount is increased, Since the adsorption rate is also increased and the arsenic compound can be effectively removed, it is preferably used by being supported on a carrier.

As the carrier, silica, alumina, silica-alumina, zeolite, ceramics, glass, resin, activated carbon or the like can be used. In particular, the adsorbent adsorbed on alumina has high dispersibility and the adsorbent of the present invention can be used. Excellent as an agent. Of the alumina, γ-alumina is particularly preferable.

[0010] What support preferably so better things large specific surface area the better the contact efficiency, 5~400m ² / g, particularly preferably those having a specific surface area of 100 to 250 m ² / g, which is limited to is not.

When supported on a carrier, the supported amount of molybdenum sulfide is 1 to 20 wt% as metal, especially 5 to 15%.
A range of wt% is preferred. If the amount supported is greater than this, the effect of the carrier is small and the dispersion becomes poor. Further, when the supported amount is small, the adsorbed amount per adsorbent becomes small. When cobalt and / or nickel is added, the addition amount is preferably 0.1 to 5 wt% as a metal with respect to the adsorbent. Further, the adsorbent may include other metal components or inorganic components.

The adsorption is from room temperature to 160 ° C., preferably room temperature to
It is carried out at 100 ° C. under a pressure condition in which the raw material hydrocarbon remains liquid. If the temperature is too high, the adsorption amount of the arsenic compound will decrease.

The method of contacting the liquid hydrocarbon containing the arsenic compound with the adsorbent is arbitrary, but the fixed bed flow system is particularly preferable. Continuous operation is possible by adopting the fixed bed distribution method. In this case, it is not preferable to mix not only hydrogen but also any gas component because it causes an increase in the scale of the apparatus.

According to the method of the present invention, a normal pressure or reduced pressure fraction of crude oil, cracked product oil, NGL or a fraction thereof, especially straight-run naphtha, kerosene, light oil, pyrolysis gasoline, catalytic cracking naphtha, N
Arsenic compounds in liquid hydrocarbons such as GL can be efficiently removed.

The present invention will be specifically described with reference to the following examples.

[0016]

[Example 1] Natural gas condensate containing no arsenic from Oceania (boiling point range: 30 to 352 ° C), and light naphtha (boiling point range: 30 to 1) using the condensate as a raw material
15 ° C), full range naphtha (boiling point range: 30 to 165)
The adsorption removal experiment of an arsenic compound was conducted using a sample obtained by adding an arsenic compound to (° C.). As the arsenic compound, triphenylarsenic As (Ph) ₃ and triethylarsenic As (Et) ₃ which are typical oil-soluble stable compounds were used. The adsorption experiment was conducted by pre-sulfiding Ni / Co / Mo with 5g of sample hydrocarbon and 42-60 mesh.
Adsorbent (metal component before sulfurization: Ni: 0.5 wt%, Co:
100 mg of 0.9 wt%, Mo: 7.0 wt%, carrier: γ-alumina) was sealed in a glass container and vigorously shaken at room temperature for 30 minutes using a shaker. After standing still,
The hydrocarbon layer was separated and the arsenic concentration was measured by the Zeeman atomic absorption spectrophotometry. The lower limit of arsenic determination by this analysis method is 2
ppb (wt). The experimental results were as shown in Table 1. All the removal rates exceeded 98%, and naphtha, in particular, was able to remove almost all.

[Table 1]

[0017]

Examples 2 to 4 and Comparative Examples 1 to 10 Model liquids prepared by adding the arsenic compound to the natural gas condensate used in Example 1 were prepared, and experiments for adsorption and removal of the arsenic compound by various adsorbents were conducted. The experimental method was the same as in Example 1. The Ni.Co.Mo sulfide of Example 2 was the same as that used in Example 1. Further, in the Ni / Mo sulfide of Example 3, the metal component before sulfidation was Ni: 1.2 wt% and Mo: 7.0 wt%, and in the Co / Mo sulfide of Example 4, the metal component before sulfidation was Co: 1. .2
The wt% and Mo: 7.0 wt% supported on γ-alumina were used after being aligned to 42-60 mesh. The experimental results are shown in Table 2.

[Table 2]

According to the results shown in Table 2, activated carbon has a relatively high removal rate for As (Et) ₃ , but has a higher removal rate for As (Ph) ₃ than an adsorbent containing a sulfide of molybdenum. Is quite low. It is clear that all other commonly used adsorbents have almost no ability to remove arsenic compounds.

[0019]

[Example 5] A model solution in which an arsenic compound was added to hexane was prepared and an adsorption removal experiment of the arsenic compound was conducted. As the arsenic compound, triethyl arsenic As (Et) ₃ , trichloroarsenic AsCl ₃ and phenylarsenic oxide C ₆ H ₅ AsO were used. In the adsorption experiment, 100 ml of the sample solution and 20 to 40 mg of the same Ni-Co-Mo sulfide adsorbent used in Example 1 were placed in a glass container and the same experiment method as in Example 1 was performed. The experimental results were as shown in Table 3. Ni / Co / Mo sulfide is As (Et)
Good adsorption capacities for ₃ , AsCl ₃ and C ₆ H ₅ AsO were shown.

[Table 3]

[0020]

【The invention's effect】

(1) Since the arsenic compound in the liquid hydrocarbon can be removed only by the adsorption step, the process is simple. (2) It can be operated at room temperature and pressure. (3) The adsorbent is inexpensive. (4) The adsorbent is a stable compound and easy to handle.

Claims (4)

[Claims] 1. A liquid hydrocarbon containing an arsenic compound,
A method for removing arsenic compounds in liquid hydrocarbons, which comprises contacting with an adsorbent containing a sulfide of molybdenum in the absence of hydrogen. 2. The arsenic compound in a liquid hydrocarbon according to claim 1, wherein the adsorbent contains a sulfide of one or two metals selected from the group consisting of cobalt and nickel in addition to molybdenum. Removal method. 3. The method for removing an arsenic compound in a liquid hydrocarbon according to claim 1 or 2, wherein the adsorbent has the sulfide supported on a carrier. 4. The method for removing an arsenic compound in a liquid hydrocarbon according to claim 3, wherein the carrier is γ-alumina.