JPH07116446B2 - Method for removing mercury in liquid hydrocarbons - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for removing mercury in liquid hydrocarbons containing mercury compounds such as natural gas condensates, especially heavy condensates.

[0002]

2. Description of the Related Art Natural gas condensates, especially heavy condensate liquid hydrocarbons, contain mercury compounds in addition to elemental mercury, and the content varies from several μg / l to several thousand μg. / L is reached.

The condensate containing mercury or naphtha obtained by distilling the condensate is used as an ethylene raw material or a reformer raw material. In the case of an ethylene plant, it causes amalgam corrosion of a low temperature heat exchanger made of aluminum or hydrogen when used as a chemical raw material. The poisoning of the noble metal catalyst for chemical purification is a problem, and the poisoning of the noble metal catalyst for reforming is a problem in the case of a reformer.

A method of removing mercury in a gas such as natural gas has already been industrially carried out using activated carbon carrying sulfur. On the other hand, industrialization is also desired for removal of mercury in liquid hydrocarbons, but removal of mercury in liquid hydrocarbons is more difficult than removal of mercury in natural gas.

The reason why it is difficult to remove mercury in liquid hydrocarbons is that liquid hydrocarbons contain not only mercury as a simple substance but also mercury compounds, and the reactivity is different, so that removal by a single method is difficult. Is. In particular, since organic mercury compounds have low reactivity, it is difficult to remove them to the level of 1 μg / l by adsorption method or extraction method.

The present inventors have previously contacted a liquid hydrocarbon or gas containing mercury with an adsorbent containing a sulfide of one or more metals selected from the group consisting of molybdenum, tungsten and vanadium. A method of removing mercury (Japanese Patent Laid-Open No. 2-2873) was proposed, in which the adsorbent is effective in removing elemental mercury, but not so much in removing organic mercury compounds and ionizable mercury. Not valid.

Further, as a method for removing mercury in a liquid hydrocarbon, a) a method in which an organic mercury compound is hydrolyzed using hydrogen and then removed by an adsorbent (JP-A 1-23).
(1990), b) heat treatment and then adsorption treatment (Japanese Patent Laid-Open No. 1-289894).

As the hydrocracking method of the above a), Ni,
A method of decomposing hydrogen at high temperature using Pd or the like as a catalyst has been proposed. In this case, in addition to the demerits of using hydrogen and removing mercury from the hydrogen discharged from the reactor, there is a problem in catalyst life such as deterioration due to adsorption of impurities in the raw material.

As the method b), at least one metal selected from iron, nickel, copper, zinc, aluminum and cadmium, its alloy or its oxide, after heat treatment of a hydrocarbon oil containing mercury, A method has been proposed in which a chloride, a sulfide, a mixture thereof, or one of them is brought into contact with a treating agent carried on the surface layer portion of the other. This heat treatment method is also an effective method, and it is also disclosed that the treatment agent is filled in a heat treatment tank to further improve the mercury removal rate, but a sufficient removal rate cannot be obtained yet.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for efficiently removing all mercury in liquid hydrocarbon over a long period of time.

[0011]

The present inventors have been studying a method for removing all mercury compounds contained in liquid hydrocarbons. when contacting the Deze zeolite catalysts, the mercury compound is decomposed easily alone mercury, the mercury is led to form a present invention found that can be readily removed by the adsorbent.

The present invention, tactile temperature Deze zeolite within a liquid hydrocarbon containing mercury compounds 150 to 300 ° C.
In this method, the mercury compound is decomposed into elemental mercury by bringing it into contact with a medium, and then the elemental mercury produced by the decomposition is adsorbed by an adsorbent mainly composed of molybdenum sulfide.

The present invention will be described in detail below. Examples of the liquid hydrocarbon used in the method of the present invention include liquid hydrocarbons obtained from natural gas or petroleum associated gas, kerosene, light oil, straight run naphtha, vacuum distillate, pyrolysis gasoline, catalytic cracking naphtha, and mercury compounds. Any of those containing can be used, but it is particularly suitable for removing mercury from natural gas condensate (NGL) having a high mercury content.

[0014] zero as the catalyst for the decomposition of mercury compounds Orai
Is preferred.

[0015] Ze O lights have various crystal structures in the crystalline aluminosilicate compound. Both H-type and cation-exchange type can be used, but cation-exchange type which can suppress the decomposition activity of hydrocarbons is more preferable. The main properties of usable zeolite are 100 to 650 m ² / g of specific surface area,
Preferably 400-600 m ² / g, pore volume 0.15
~ 0.39 cm ³ / g, preferably 0.18 to 0.36
cm ³ / g.

The decomposition temperature is 150 to 300 ° C, preferably 180 to 250 ° C. The decomposition of the mercury compound is not sufficient at 150 ° C. or lower, and the decomposition is possible at 300 ° C. or higher, but it is not preferable because it causes decomposition or polymerization of hydrocarbons and is disadvantageous in terms of cost.

The pressure may be any pressure that can keep the liquid hydrocarbon in a liquid state, and a pressure of 20 to 50 kg / cm ² is usually used. The liquid space velocity (SV) is 0.1 to 8
The range may be 0 / hour, and the reaction is preferably performed at a rate of 1 to 25 / hour. If the SV is too large, the decomposition of the mercury compound will be insufficient.

As the adsorbent, one mainly composed of molybdenum sulfide is used. Molybdenum sulfide has an extremely high mercury adsorption activity, but in order to further improve the mercury adsorption effect of molybdenum sulfide, it is effective to use it as a composite sulfide in combination with cobalt and / or nickel. is there. When cobalt and / or nickel sulfides molybdenum oxide, it initiates sulfide at a lower temperature, and at the same time, cobalt and / or nickel is incorporated into crystals of molybdenum sulfide to prevent 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. If the atomic ratio is 0.05 or less, the effect of dispersion is small, while if it is increased to 0.9 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 carried on a carrier, the dispersity of the adsorbent is improved and not only the adsorption amount is increased, Since the adsorption rate also increases, it is preferable to support the carrier for use.

As the carrier, silica, alumina, silica-
Alumina, zeolite, porous ceramics, porous glass, activated carbon or the like can be used, but the adsorbent adsorbed on alumina has a high dispersibility and is excellent as the adsorbent of the present invention. Of the alumina, γ-alumina is particularly preferable.

When supported on a carrier, the amount of molybdenum sulfide supported is 1 to 20% by weight as a 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.

The adsorption temperature of the adsorbent is 200 ° C. or lower, preferably 130 ° C. or lower. In particular, a temperature of 100 ° C. or lower is preferable from the standpoint of increasing the adsorption amount of mercury. The liquid linear velocity during adsorption is 0.01 cm / sec or more, preferably 0.1 c
m / sec or more.

[0023]

The present invention will be described in detail below based on examples and comparative examples, but the present invention is not limited to these examples.

Firstly, alpha - alumina catalyst, and zeolite <br/> catalysts is to show that it has a degrading activity of the organic mercury compound, the following experiment was performed.

[0025] Example 1, in the ratio Comparative Examples 1-2 In this experiment, the addition of diethyl mercury, mercury content 50μ which may mercury content 410μg / l (inner ionization
g / l, organic mercury content of 360 μg / l) heavy naphtha (IBP 105 ° C., FBP 162 ° C., specific gravity 15 /
4 ° C. 0.742) was used as the starting hydrocarbon oil.

A stainless reaction tube having an inner diameter of 8 mm was filled with 1 ml of the following catalyst, and the temperature was 180 ° C. and the pressure was 30 kg / cm.
^The feedstock hydrocarbon oil was fed at a flow rate of 52 ml / hr under ² G conditions. At this time, the liquid hourly space velocity (SV) is 52 hr ⁻¹ .

Catalyst; (1) Molecular sieve 4A (NaA) (catalyst (1) ) having a specific surface area of 250 m ² / g and a particle size of 1 to ² mm (2) Specific surface area of 1 m ² / g or less and a particle size of 1 to ² mm Α-
Al ₂ O ₃ ball (catalyst (2) ). Note: Catalyst (2) is a comparative example. The results are shown in Table 1.

[0028]

[Table 1]

[0029] shown in Table 1 result either et al, although Ze zeolite has a high activity (Example 1), alpha-alumina is found to be ineffective.

Example 2 , Comparative Example 3 Total mercury content of 440 μg / diethyl mercury was added.
1, a natural gas condensate from Southeast Asia with an organic mercury content of 390 μg / l (as mercury) was filled in a stainless steel reaction tube having an inner diameter of 14 mm with 20 ml of the catalyst shown in Table 2,
While heating to the temperature shown in Table 2, pressure 30 kg / cm ²
G, the flow rate was 52 ml / hour. At this time, the liquid hourly space velocity (SV) is 2.6 hr ⁻¹ . Then, the decomposed condensate was added to a glass column having an inner diameter of 3 mm in an amount of 0.1
An adsorbent, which was crushed to 3 to 0.5 mm, was a sulfide that contained Mo 6.9% by weight, Co 0.9% by weight, and Ni 0.4% by weight as an unsulfurized composition on alumina (Adsorbent (1) ) Passed at room temperature over an adsorbent filled with 1.0 ml. The outlet was opened under atmospheric pressure. The results are shown in Table 2.

[0031]

[Table 2] *) Aluminum metal, 16-32 mesh, 20 ml
use.

Example 3 and Comparative Example 4 Diethyl mercury was added to n-hexane to give 40% mercury.
A simulated solution containing 0 μg / l was prepared. The same apparatus as in Example 2 was used for catalytic cracking, and 20 mL of each cracking catalyst was charged. The decomposition temperature was 225 to 230 ° C., and the pressure and flow rate were the same as in Example 2 . For the adsorption, 1.0 ml of each adsorbent was filled in the same apparatus as in Example 2 . At this time, the liquid linear velocity is 0.20
cm / sec. The temperature and pressure were the same as in Example 2 .

[0033]

[Table 3]

[0034]

According to the present invention, mercury contained in liquid hydrocarbon can be efficiently removed.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C10G 25/03 6958-4H 29/16 6958-4H (72) Inventor Toru Matsuzawa Tosaki, Hino, Handa City, Aichi Prefecture 2-110 Machi, Kinuura Research Institute, JGC Co., Ltd. (72) Inventor, Kazuo Sato, 2-110, Kinoura, Kinoura Co., Ltd., Handa City, Aichi Prefecture (56) Reference JP-A-1-289894 (JP, A) JP-A-2-2873 (JP, A) JP-A-4-11690 (JP, A) JP-A-4-50294 (JP, A) JP-A-4-227794 (JP, A)

Claims (3)

[Claims] 1. A liquid hydrocarbon containing a mercury compound
By contacting at a temperature Deze zeolite catalysts of 50 to 300 ° C., after decomposing the aqueous silver compound to elemental mercury, to adsorb and remove elemental mercury produced decomposed by an adsorbent composed mainly of sulfides of molybdenum A method for removing mercury in a liquid hydrocarbon, which is characterized. 2. A liquid hydrocarbon containing a mercury compound
80~250 ℃, SV0.1~80 / time conditions Deze O <br/> light touch method for removing mercury in a liquid hydrocarbon according to claim 1, wherein contacting the medium. 3. The method for removing mercury in a liquid hydrocarbon according to claim 1, wherein the adsorbent contains a sulfide of molybdenum and a sulfide of cobalt and / or nickel.