JP2002212572A - Method for removing mercury from liquid hydrocarbon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semi-continuous method for easily removing mercury from a mercury-containing liquid hydrocarbon nearly under the normal temperature and pressure conditions. SOLUTION: Mercury is removed from a mercury-containing liquid hydrocarbon by (A) supplying the liquid hydrocarbon to an ionization column and bringing the hydrocarbon into contact with a substance capable of ionizing the elemental mercury in the liquid hydrocarbon to effect the ionization treatment and (B) supplying the treated liquid hydrocarbon containing the ionized mercury to a sulfur compound treating column to bring the hydrocarbon into contact with a sulfur compound expressed by general formula MM'S (M and M' are each independently H, an alkali metal or ammonium) or with a liquid containing the sulfur compound to effect the solidification of mercury and separating the solidified mercury from the hydrocarbon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for removing mercury from liquid hydrocarbons containing mercury.

[0002]

2. Description of the Related Art In NGL (natural gas liquid) produced from a natural gas field, that is, liquid hydrocarbons such as liquefied petroleum gas and condensate, mercury reaching 2 to several thousand ppb varies depending on the producing area. Some of them are contained, and light hydrocarbons obtained by distilling these NGLs sometimes contain mercury. If such hydrocarbons are to be used as a raw material for chemicals, the mercury contained in them will cause amalgam corrosion of aluminum used as equipment material and cause deterioration of the reforming catalyst. Development has been strongly desired. As a device for this development, JP-A-10-251667 discloses that a hydrocarbon fraction containing mercury is subjected to a hydrogenation treatment, and the hydrocarbon fraction after the hydrogenation treatment is brought into contact with a porous carbon material. A method for adsorbing and removing trace amounts of mercury in a hydrocarbon fraction by a combination of the above-mentioned hydrogenation treatment and adsorption treatment is disclosed. In this method, a reaction temperature of 1
It required conditions of 00 to 400 ° C., preferably 250 to 350 ° C., and a reaction pressure of 1 to 5 MPa, preferably 2.5 to 3.5 MPa, and high temperature and high pressure, and required energy for heating and pressurizing. Further, as the porous carbon material is a sorbent, a specific surface area of 100~2500m ² / g, preferably from 500 to 1500 ² / g, an average pore radius of 5 to 3
The volume of pores having a diameter of 0 Å and a pore radius of 50 Å or less was 0.2 to 1.2 ml / g, which required an extremely complicated process for preparing the adsorbent.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for removing mercury from a liquid hydrocarbon containing mercury in a semi-continuous, simple and efficient manner near normal temperature and normal pressure. .

[0004]

Means for Solving the Problems As a result of intensive studies, the present inventors have continuously supplied mercury-containing hydrocarbons to a mercury ionization treatment tower, and then batch-processed in a sulfur compound treatment tank. It has been found that it is effective to solidify mercury and remove mercury from liquid hydrocarbons. The present invention
It has been completed based on such knowledge. That is, in the present invention, in removing mercury from a liquid hydrocarbon containing mercury, (A) the liquid hydrocarbon is supplied to an ionization treatment tower, and the ionization ability of a single substance contained in the liquid hydrocarbon with respect to mercury is reduced. (B) Then, the obtained liquid hydrocarbon containing ionized mercury is supplied to a sulfur compound treatment tank,
General formula MM'S (where M and M 'are the same or different,
Each is independently a hydrogen, alkali metal or ammonium group. The present invention provides a method for removing mercury from liquid hydrocarbons, which comprises contacting with a sulfur compound represented by the formula (1) or a liquid containing the sulfur compound to solidify and separate mercury.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The liquid hydrocarbon containing mercury to be treated in the present invention is not particularly limited as long as it is a liquid hydrocarbon at room temperature. For example, crude oil, straight run naphtha, kerosene, light oil, vacuum distillate, atmospheric residue, natural gas condensate and the like can be mentioned, but natural gas condensate (NGL) is particularly preferable.

The form of mercury removed by the method of the present invention is
Either simple mercury or ionic mercury may be used. The concentration of mercury in the liquid hydrocarbon is not particularly limited, but is usually 2 to 1,000 W / Vppb, preferably 5 to 100 W / Vppb.
W / Vppb.

[0007] The crude oil is not particularly limited.
For example, Saudi crude, UAE, Nigeria, Algeria, Canada, Mexico, Iran, Iraq, China, Kuwait, Malaysia, Venezuela. Crude oil, US crude oil, Australian crude oil, Russian crude oil, Libyan crude oil, Philippine crude oil, Indonesian crude oil, Norwegian crude oil, Thai crude oil, Qatar crude oil, Argentine crude oil, British crude oil, Japanese crude oil and These mixed crude oils are mentioned. The straight-run naphtha, kerosene, light oil, reduced-pressure distillate or normal-pressure residue is not particularly limited, and examples thereof include those obtained by treating the above-mentioned crude oil by an ordinary method.

In the present invention, the liquid hydrocarbon as described above is supplied to an ionization treatment tower which is brought into contact with a substance having an ionizing ability for simple mercury contained in the liquid hydrocarbon. Here, a substance capable of ionizing mercury alone (hereinafter sometimes referred to as a mercury ionized substance) is, for example, iron sulfate, iron chloride, iron sulfide, iron oxide, iron nitrate, iron oxalate, or the like. Compound (preferably 3
(Valent iron compound), copper sulfate, copper chloride, copper oxide, copper nitrate,
Copper compounds such as copper sulfide, vanadium compounds, manganese compounds (preferably manganese dioxide), nickel compounds,
Examples include organic or inorganic peroxides such as hydrogen peroxide and peracetic acid, and sludge existing in a crude oil tank. These may be used alone or in combination of two or more. Here, as an example of elemental analysis of sludge present in the crude oil tank, Fe; 36 wt%, Si;
3 wt%, Na: 3600 wtppm, Al: 2700
wtppm, P: 2200 wtppm, Zn: 2100
wtppm, Cu; 950 wtppm, Ca; 720w
tppm, Mg: 550 wtppm, V: 350 wtp
pm, K: 350 wtppm, Cr: 290 wtpp
m, Mn: 230 wtppm, Ni: 120 wtpp
m, C: 32.0 wt%, H: 3.0 wt%, N: 0.
9 wt%, S: 3.0 wt%, Cl: 0.4 wt%.

The manganese compound such as manganese dioxide can be used in any form such as powder, crushed, cylindrical, spherical, fibrous, and honeycomb. Also,
It can also be used as a form supported on silica, alumina, silica-alumina, zeolite, ceramic, glass, resin or activated carbon. The loading amount is not particularly limited, but is preferably 0.1 to 30% by weight based on the carrier.

In the method of the present invention, as described above, the liquid hydrocarbon is supplied to the ionization treatment tower and is brought into contact with the mercury ionization treatment substance to convert single mercury into ionic mercury. At this time, the reaction temperature is −50 ° C. to 100 ° C., preferably 0 to 60 ° C., the pressure is 0 to 2 MPa,
Basically, any pressure may be used as long as the liquid is maintained at the reaction temperature used.

In the present invention, the liquid hydrocarbon that has passed through the ionization tower is converted into the general formula MM'S (wherein M
And M ′ are the same or different and are each independently a hydrogen, an alkali metal or an ammonium group. ) Or a liquid containing the sulfur compound (particularly an aqueous solution), and supplied to the sulfur compound treatment tank in a batch manner.
Water may be present in the liquid hydrocarbon supplied to the sulfur compound treatment tank, and water may be appropriately added to the liquid hydrocarbon supplied to the treatment tank. General formula MM'S
Examples of the sulfur compound represented by include hydrogen sulfide, sodium hydrosulfide, potassium hydrosulfide, sodium sulfide, potassium sulfide, and ammonium sulfide. Of these, hydrogen sulfide is particularly preferred. The concentration of the sulfur compound in the liquid containing the sulfur compound is not particularly limited, but is preferably 0.1 to 100,000 W / W.
ppm, more preferably 1 to 1,000 W / Wppm
It is.

The hydrogen sulfide can be supplied in a liquid state by applying a gas or pressure. Further, it may be supplied in the form of water or an organic solvent containing hydrogen sulfide,
It may be supplied in the form of an organic solvent mixture. The supply ratio of the sulfur compound represented by the above general formula is 1 to 10000 of the sulfur compound per 1 mol of mercury contained in the liquid hydrocarbon.
The molar ratio is suitably 100 times, preferably 100 to 5000 times. The mixing of the sulfur compound and the liquid hydrocarbon is not particularly limited, and stirring with a mixer, stirring with a line mixer installed in front of the sulfur compound treatment tank, or the like can be selected. In a treatment tank using a sulfur compound, the reaction temperature is from -50C to 100C, preferably from 0 to 6C.
The temperature is 0 ° C. and the pressure is 0 to 2 MPa.

After the mercury ionization treatment according to the method of the present invention, when the mercury is contacted with a sulfur compound as described above, a solid product of mercury can be obtained. It is preferable that the solid matter of mercury be removed by solid-liquid separation in the same tank as the tank that has been treated with the sulfur compound. That is, the generated mercury solid is
After standing for at least 6 hours, more preferably for at least 12 hours, especially for at least 24 hours after contact with the sulfur compound, the liquid hydrocarbons are separated from liquid hydrocarbons by ordinary solid-liquid separation means such as filtration and sedimentation Can be removed.

[0014]

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1 Mercury content: 37 W / Vppb (simple: ionic = 77)
%: 23%) of condensate A [density (g / cm ³ ,
0.7363] was supplied to an ionization tower filled with 0.3 liter of the following mercury ionization substance, and mercury was ionized under the following conditions. Reaction temperature: 25 ° C. Reaction pressure: 0.1 MPa (absolute pressure) Liquid space velocity: 10 hr ⁻¹ Mercury ionized material: manganese dioxide As a result, the mercury content is 37 W / Vppb (simple: ionic = 0%: 100%) ) Was obtained. The condensate A thus obtained [mercury content 3
7W / Vppb (simple: ionic = 0%: 100
%)] And hydrogen sulfide were supplied to a tank-type container (50 liters in internal volume) equipped with a stirrer, and mercury was solidified under the following conditions. Reaction temperature: 25 ° C. Reaction pressure: 0.1 MPa (absolute pressure) Time: 12 hr Hydrogen sulfide / mercury: 1000 (molar ratio) After the above-mentioned hydrogen sulfide treatment, after 20 hours in a standing state, the container (50) Condensate A was extracted from the liter), and the mercury concentration was measured to be 1.8 W / Vpp.
b.

Example 2 In the same manner as in Example 1, condensate A was supplied to a mercury ionization treatment tower and treated with hydrogen sulfide to obtain condensate A in which mercury was present as a solid. After the hydrogen sulfide treatment, 24 hours and 48 hours had elapsed after standing, and condensate A was taken out of the container, and each mercury concentration was measured. As a result, both were 1.1 W / Vppb.

[0017]

According to the present invention, mercury can be reduced from liquid hydrocarbon containing mercury to 2 W / Vppb or less semi-continuously and easily at normal temperature and near normal pressure.

Claims (6)

[Claims] 1. In removing mercury from a liquid hydrocarbon containing mercury, (A) the liquid hydrocarbon is supplied to an ionization treatment tower, and has an ionizing ability with respect to a single mercury contained in the liquid hydrocarbon. (B) Then, the obtained liquid hydrocarbon containing ionized mercury is supplied to a sulfur compound treatment tank,
General formula MM'S (where M and M 'are the same or different,
Each is independently a hydrogen, alkali metal or ammonium group. A method for removing mercury from liquid hydrocarbons, comprising contacting with a sulfur compound represented by the formula (1) or a liquid containing the sulfur compound to solidify and separate mercury. 2. The method for removing mercury from liquid hydrocarbons according to claim 1, wherein the produced mercury solids are removed by solid-liquid separation in the same tank as the sulfur compound treatment tank. 3. The method for removing mercury from a liquid hydrocarbon according to claim 1, wherein the sulfur compound is hydrogen sulfide. 4. The sulfur compound treatment condition is a temperature of -50 ° C.
The method for removing mercury from a liquid hydrocarbon according to claim 1, wherein the temperature is 100 ° C and the pressure is 0 to 2 MPa. 5. In a sulfur compound treatment tank, the sulfur compound is added in an amount of 1 to 10 with respect to 1 mol of mercury in a liquid hydrocarbon.
The method for removing mercury from a liquid hydrocarbon according to claim 1, wherein the supply is performed by 000 mole times. 6. The liquid hydrocarbon according to claim 1, wherein, after leaving in the sulfur compound treatment tank for at least 6 hours after contact with the sulfur compound, (C) the produced mercury solid is removed by solid-liquid separation. Mercury removal method.