JP3824460B2 - How to remove mercury - Google Patents

Description

【００１９】
実験例２
水銀を含有するコンデンセート ５００ミリリットルをテフロン製容器に入れ、酸素８ｖｏｌ％、窒素９２ｖｏｌ％の混合ガスを、毎分２５０ミリリットルで１時間吹込んだ. このときのコンデンセートのＣ／Ｃ’の値は０．３８であった。
【００２０】
実験例３
水銀を含有するコンデンセート ５００ミリリットルと５グラムの亜硫酸ナトリウムをテフロン製容器に入れ、１時間攪拌した。このときのコンデンセートのＣ／Ｃ’の値は０．００であった。
【００２１】
実施例１
硫化水素を７００ｐｐｍ含有する水溶液 ２重量部と、Ｃ／Ｃ’＝０の水銀を含有するコンデンセート（水銀濃度２７Ｗ／Ｖｐｐｂ） １０００重量部及び四三酸化鉄 ０．０１重量部をカーボンスティール製容器に入れ、３時間攪拌して水銀除去処理をした後静置した。静置後、孔径０．４５μｍのメンブランフィルターを用いて固体を除いたコンデンセート中の水銀濃度を測定したところ１Ｗ／Ｖｐｐｂ以下であった。これを、３週間静置しても水銀濃度は１Ｗ／Ｖｐｐｂ以下であった。その時の水銀濃度の経時変化を図１に示す。
【００２２】
実施例２
実施例１において、カーボンスティール容器の代わりにテフロン容器を用いたこと以外は同様の条件で水銀除去処理をしたところ、３時間後のコンデンセート中の水銀濃度は１Ｗ／Ｖｐｐｂ以下であり、３週間静置後もコンデンセート中の水銀濃度は１Ｗ／Ｖｐｐｂ以下であった。
【００２３】
実施例３
実施例１において、硫化水素を７００ｐｐｍ含有する水溶液２重量部の代わりに、硫化水素ガス０．００１４重量部を用いたこと以外は同様の条件で水銀除去処理をしたところ、３時間後のコンデンセート中の水銀濃度は１Ｗ／Ｖｐｐｂ以下であり、３週間静置後もコンデンセート中の水銀濃度は１Ｗ／Ｖｐｐｂ以下であった。
【００２４】
実施例４〜６
実施例１において、Ｃ／Ｃ’＝０の水銀を含有するコンデンセートの代わりに、Ｃ／Ｃ’＝０．１０（実施例４）、０．２４（実施例５）、０．０８（実施例６）の水銀を含有するコンデンセートを用いたこと以外は同様の条件で水銀除去処理をしたところ、３時間後のコンデンセート中の水銀濃度は実施例４〜６全て１Ｗ／Ｖｐｐｂ以下であった。また、３週間静置後のコンデンセート中の水銀濃度は実施例４〜６全て１Ｗ／Ｖｐｐｂ以下であった。
【００２５】
実施例７
実施例１において、硫化水素を７００ｐｐｍ含有する水溶液２重量部の代わりに、硫化水素ガス０．０００７重量部を用いたこと以外は同様の条件で水銀除去処理をしたところ、３時間後のコンデンセート中の水銀濃度は１Ｗ／Ｖｐｐｂ以下であり、３週間静置後もコンデンセート中の水銀濃度は１Ｗ／Ｖｐｐｂ以下であった。
【００２６】
実施例８
実施例１において、硫化水素を７００ｐｐｍ含有する水溶液２重量部の代わりに、硫化水素ガス０．０７重量部を用いたこと以外は同様の条件で水銀除去処理をしたところ、３時間後のコンデンセート中の水銀濃度は１Ｗ／Ｖｐｐｂ以下であり、３週間静置後もコンデンセート中の水銀濃度は１Ｗ／Ｖｐｐｂ以下であった。
【００２７】
実施例９
硫化水素ガス０．０００１４重量部と、Ｃ／Ｃ’＝０の水銀を含有するコンデンセート（水銀濃度５Ｗ／Ｖｐｐｂ） １０００重量部及び四三酸化鉄 ０．０１重量部をカーボンスティール製容器に入れ、３時間攪拌して水銀除去処理をした後静置した。静置後、孔径０．４５μｍのメンブランフィルターを用いて固体を除いたコンデンセート中の水銀濃度を測定したところ１Ｗ／Ｖｐｐｂ以下であった。これを、３週間静置しても水銀濃度は１Ｗ／Ｖｐｐｂ以下であった。
【００２８】
比較例１
水銀を含有するコンデンセート ５００ミリリットルをカーボンスティール製容器に入れ、酸素２１ｖｏｌ％のガスを、毎分２５０ミリリットルで１時間吹込んだ。このときのＣ／Ｃ’の値は１．００であった。
実施例１において、Ｃ／Ｃ’＝０の水銀を含有するコンデンセートの代わりに、上記Ｃ／Ｃ’＝１の水銀を含有するコンデンセートを用いたこと以外は同様の条件で水銀除去処理をしたところ、３時間攪拌して水銀除去処理をした後静置した後の水銀濃度を測定すると１Ｗ／Ｖｐｐｂ以下であった。その後、さらに静置すると、２１時間後から徐々にコンデンセート中の水銀濃度が上昇し、３週間後には２７Ｗ／Ｖｐｐｂとなった。その時の水銀濃度の経時変化を図２に示す。
【００２９】
【発明の効果】
以上詳細に説明したように、本発明によれば、極めて簡便な手段により、効率的に、水銀を含有する液状炭化水素の水銀濃度を１Ｗ／Ｖｐｐｂ以下に低減し、しかも水銀濃度の再上昇を抑制可能である。
【図面の簡単な説明】
【図１】 実施例１において、水銀除去処理をした液状の炭化水素を静置した時間と水銀濃度の関係を示す図である。
【図２】 比較例１において、水銀除去処理をした液状の炭化水素を静置した時間と水銀濃度の関係を示す図である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for removing mercury, and more particularly, to a method for efficiently removing mercury from liquid hydrocarbons containing mercury by simple means.
[0002]
[Prior art]
NGL (natural gas liquid) recovered by removing liquefied petroleum gas from the natural gas field contains 2 to several thousand ppb of mercury, although it varies depending on the production area, and is obtained by distilling these NGL. Some light hydrocarbons also contained mercury.
Mercury contained in the hydrocarbon thus obtained has caused amalgam corrosion of aluminum used as a device material and deterioration of the hydrogenation catalyst when used as a chemical raw material. In addition, when dissolved oxygen is present due to contact with NGL air, the mercury concentration in NGL decreases once, but is dissolved in NGL again.
For this reason, it has been desired to develop a mercury removal technique that can efficiently remove mercury from liquid hydrocarbons containing mercury and that does not increase the mercury concentration again.
[0003]
For example, Japanese Examined Patent Publication No. 4-28040 discloses a method for removing mercury present in hydrocarbons. MM ′S (M and M ′ are the same or different, and each independently represents hydrogen. And a method for removing mercury comprising a step of treating with a sulfur compound represented by the following formula: and a step of contacting with an adsorbent containing one or more heavy metal sulfides. ing. In Japanese Patent Publication No. 6-89338, MM′Sx (M and M ′ are the same or different and each independently represents hydrogen, an alkali metal, or an ammonium group, and x is 1 to 6). The mercury removal method characterized by making it contact with the aqueous solution containing the sulfur compound made at the temperature of 40 degreeC or more is disclosed.
However, in the method described in Japanese Patent Publication No. 4-28040, mercury is removed by injecting hydrogen sulfide gas into mercury-containing liquid hydrocarbon and adsorbing it on an adsorbent in which molybdenum and cobalt sulfide are supported on alumina. However, since the process is complicated and includes an adsorption operation, complicated preparation of the adsorbent and strict management of operating conditions are required. In the preparation of the adsorbent, the physical properties of the adsorbent change due to various factors. As a result, it affects the process of removing mercury from hydrocarbons, making it difficult to prepare an adsorbent for stable mercury adsorption. Met. In addition, depending on the type of liquid hydrocarbon, for example, when it contains a large amount of mercaptan, once adsorbed mercury was again converted into mercaptide mercury and redissolved in liquid hydrocarbon,
In addition, in the method described in Japanese Patent Publication No. 6-89338, when the temperature is 40 ° C. or less, the residual mercury concentration in the hydrocarbon after the mercury removal treatment is very high as 30 to 170 ppb, and the treatment temperature is 100 to 120 ° C. Although the residual mercury concentration was decreased to 0 to 30 ppb by increasing the temperature, the concentration could be as high as 30 ppb, which was not a satisfactory value.
Further, in the methods described in these publications, the mercury concentration once decreased may increase again.
[0004]
[Problems to be solved by the invention]
The present invention has been made in order to solve the above-mentioned problems. The mercury concentration of liquid hydrocarbons containing mercury is reduced to 1 W / Vppb or less, and it is possible to suppress the re-elevation of the mercury concentration, which is simple and efficient. The object is to provide a method for removing mercury well.
[0005]
[Means for Solving the Problems]
As a result of intensive studies, the inventors of the present invention have included a liquid hydrocarbon in equilibrium with a gas having a specific oxygen concentration, a specific sulfur compound, an aqueous solution thereof, or hydrogen sulfide present in a crude oil tank . an aqueous solution, by contacting a specific substance having ion Kano for mercury, found that can achieve the above objects, and completed the present invention.
That is, in the present invention, when removing mercury from a liquid hydrocarbon containing mercury, the present invention contains a liquid that contains mercury and does not contain dissolved oxygen or contains dissolved oxygen in equilibrium with a gas having an oxygen concentration of 8 vol% or less. Hydrocarbon, (A) a sulfur compound represented by the general formula MM ′S (M and M ′ are the same or different, and each independently represents hydrogen, an alkali metal or an ammonium group), and an aqueous solution containing the sulfur compound Or an aqueous solution containing hydrogen sulfide present in a tank for crude oil, and (B) mercury which is brought into contact with the following substance having ionization ability with respect to a single mercury contained in the hydrocarbon to remove mercury: This is a removal method. Here, substances capable of ionizing single mercury are iron sulfate, iron chloride, iron oxide, iron nitrate, copper sulfate, copper chloride, copper oxide, copper nitrate, manganese compound, nickel compound, inorganic peroxide, organic One selected from peroxide and sludge present in crude oil tanks.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The liquid hydrocarbon containing mercury to be treated in the present invention is not particularly limited as long as it is a hydrocarbon that is liquid at room temperature.
For example, crude oil, straight-run naphtha, kerosene, light oil, vacuum distillate oil, atmospheric residue oil or natural gas condensate can be mentioned, and natural gas condensate (NGL) is particularly preferable.
[0007]
The form of mercury removed by the method of the present invention may be either elemental mercury or ionic mercury.
The mercury concentration in the liquid hydrocarbon is not particularly limited, but is usually 2 to 1,000 W / Vppb, preferably 5 to 100 W / Vppb.
The dissolved oxygen concentration contained in the liquid hydrocarbon is 8 vol% or less, preferably 6 vol% or less, more preferably 3 vol% or less. In particular, it is most preferable not to contain dissolved oxygen.
[0008]
The above crude oil is not particularly limited, for example, Saudi crude oil, UAE crude oil, Nigeria crude oil, Canadian crude oil, Mexican crude oil, Iranian crude oil, Iraqi crude oil, Chinese crude oil, Kuwait crude oil , Malaysian crude oil, Venezuelan crude oil, American 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, UK Crude oil, Japanese crude oil and mixed crude oil of these.
The straight-run naphtha, kerosene, light oil, vacuum distillate oil or atmospheric residue oil is not particularly limited, and examples thereof include those obtained by treating the above crude oil by a conventional method.
[0009]
M and M ′ represented by the general formula MM ′S of the component (A) are the same or different and are each independently hydrogen, an alkali metal, or an ammonium group. Here, examples of the alkali metal include sodium, potassium, lithium and cesium.
Examples of the sulfur compound represented by the general formula MM ′S include hydrogen sulfide, sodium hydrosulfide, potassium hydrosulfide, sodium sulfide, potassium sulfide, and ammonium sulfide.
The concentration of the aqueous solution containing the sulfur compound represented by the general formula MM ′S is preferably 10 to 100,000 W / Wppm, and more preferably 10 to 10,000 W / Wppm.
The liquid present in the crude oil tank, and a water solution containing hydrogen sulfide.
[0010]
(B) above substance having an ionic Kano for a single mercury contained in the hydrocarbon component, for example, iron sulfate, iron chloride, acid iron, iron compounds such as iron nitrate, copper sulfate, copper chloride, copper oxide copper compounds such as copper nitrate, manganese compounds, nickel compounds, hydrogen peroxide, an organic such as peracetic acid, inorganic peroxides, and the like sludge present in the crude oil tank. These may be used alone or in combination of two or more. As an example of elemental analysis of sludge present in crude oil tanks, Fe 36 wt%, Si 1.3 wt%, Na 3600 wt ppm, Al 2700 wt ppm, P 2200 wt ppm, Zn 2100 wt ppm, Cu 950 wt ppm, Ca 720 wt ppm, Mg 550 wt ppm, V 350 wtppm, K 350 wtppm, Cr 290 wtppm, Mn 230 wtppm, Ni 120 wtppm, C 32.0 wt%, H 3.0 wt%, N 0.9 wt%, S 3.0 wt%, Cl 0.4 wt%.
[0011]
Specifically, the mercury removal method of the present invention is as follows.
First, the dissolved oxygen in the hydrocarbon can be reduced by treating with a gas having an oxygen concentration of 8 vol% or less in contact with the hydrocarbon, or by treating with a deoxygenating agent such as sodium sulfite. Examples of the gas composition having an oxygen concentration of 8 vol% or less include oxygen 1.7 vol%, nitrogen 97 vol%, and carbon dioxide 1.3 vol%. The oxygen concentration may be 8 vol% or less, the ratio of other components can be arbitrarily selected, and SOx, NOx, etc. may exist.
[0012]
A hydrocarbon containing mercury and a gas having an oxygen concentration of 8 vol% or less are contact-mixed under conditions of a temperature of 0 to 40 ° C. and a pressure of atmospheric pressure to 1 MPa to reduce the oxygen concentration in the hydrocarbon. As a method of bringing the liquid hydrocarbon containing mercury treated in this way into contact with the above components (A) and (B), a contact by stirring or a contact method using a line mixer can be adopted, but there is no particular limitation. Absent.
[0013]
The procedure for contacting the treated liquid hydrocarbon containing mercury with the components (A) and (B) is the step of contacting the component (A) with the component (B) first after contacting the component (B) with the hydrocarbon. Or the hydrocarbon may be contacted simultaneously with the component (A) and the component (B), and the component (A) is first contacted with the hydrocarbon, and then the component (B) is contacted. You may let them.
[0014]
The contact mixing ratio of the component (A) and the liquid hydrocarbon containing mercury can be arbitrarily selected at a weight ratio of 0.000001 to 1000 to 1000 to 0.1, but 0.0001 to 1000. From 500 to 1000 is also economically preferable.
The contact mixing ratio of the component (B) and the liquid hydrocarbon containing mercury can be arbitrarily selected at a weight ratio of 0.0001 to 1000 to 1: 1, but is 0.001 to 1000 to 10. The pair 1000 is also economically preferable.
[0015]
The temperature at which the components (A) and (B) are brought into contact with the liquid hydrocarbon containing mercury may be any hydrocarbon as long as the hydrocarbon is maintained in a liquid state. For example, if the pressure is 1 MPa, a temperature range of 0 to 180 ° C. may be used.
[0016]
The contact method of the (A) and (B) components and the liquid hydrocarbon containing mercury is, for example, stirring in a tank with stirring blades, stirring with a line mixer, rotation of the container itself, stirring by vibration, etc. Although there is no particular limitation, the contact time is 3 seconds to 24 hours, and there is no problem even if it exceeds 24 hours, but this is not economically preferable.
Mercury removed from the hydrocarbon is removed as a solid from the liquid phase of the hydrocarbon and water. The method can select solid-liquid separation means such as decantation and filtration, but is not particularly limited.
[0017]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples.
Experimental example 1
500 ml of condensate containing mercury was put in a carbon steel container, and a mixed gas of 8 vol% oxygen and 92 vol% nitrogen was blown in at 250 ml per minute for 1 hour. When the dissolved oxygen concentration in the condensate at this time is C, and the dissolved oxygen concentration in the condensate when air is blown in at 250 ml / min for 1 hour is C ′, the value of C / C ′ is 0.38. Met.
Table 1 below shows the measurement results of C / C ′ when various mixed gases were blown.
[0018]
[Table 1]

[0019]
Experimental example 2
500 ml of condensate containing mercury was put into a Teflon container, and a mixed gas of 8 vol% oxygen and 92 vol% nitrogen was blown in at 250 ml per minute for 1 hour. At this time, the C / C ′ value of the condensate was 0 .38.
[0020]
Experimental example 3
500 milliliters of condensate containing mercury and 5 grams of sodium sulfite were placed in a Teflon container and stirred for 1 hour. The value of C / C ′ of the condensate at this time was 0.00.
[0021]
Example 1
2 parts by weight of an aqueous solution containing 700 ppm of hydrogen sulfide, 1000 parts by weight of condensate containing mercury of C / C ′ = 0 (mercury concentration 27 W / Vppb) and 0.01 parts by weight of iron tetroxide are contained in a carbon steel container. The mixture was stirred for 3 hours to remove mercury and left to stand. After standing, when the mercury concentration in the condensate excluding the solid was measured using a membrane filter having a pore diameter of 0.45 μm, it was 1 W / Vppb or less. Even if this was left for 3 weeks, the mercury concentration was 1 W / Vppb or less. The time-dependent change of the mercury concentration at that time is shown in FIG.
[0022]
Example 2
In Example 1, mercury removal treatment was performed under the same conditions except that a Teflon container was used instead of the carbon steel container. As a result, the mercury concentration in the condensate after 3 hours was 1 W / Vppb or less, Even after placement, the mercury concentration in the condensate was 1 W / Vppb or less.
[0023]
Example 3
In Example 1, mercury removal treatment was performed under the same conditions except that 0.0014 parts by weight of hydrogen sulfide gas was used instead of 2 parts by weight of an aqueous solution containing 700 ppm of hydrogen sulfide. The mercury concentration was 1 W / Vppb or less, and the mercury concentration in the condensate was 1 W / Vppb or less after standing for 3 weeks.
[0024]
Examples 4-6
In Example 1, instead of the condensate containing mercury of C / C ′ = 0, C / C ′ = 0.10 (Example 4), 0.24 (Example 5), 0.08 (Example) When mercury removal treatment was performed under the same conditions except that the condensate containing mercury of 6) was used, the mercury concentration in the condensate after 3 hours was 1 W / Vppb or less in all Examples 4 to 6. Further, the mercury concentration in the condensate after standing for 3 weeks was 1 W / Vppb or less in all Examples 4 to 6.
[0025]
Example 7
In Example 1, mercury was removed under the same conditions except that 0.0007 parts by weight of hydrogen sulfide gas was used instead of 2 parts by weight of an aqueous solution containing 700 ppm of hydrogen sulfide. The mercury concentration was 1 W / Vppb or less, and the mercury concentration in the condensate was 1 W / Vppb or less after standing for 3 weeks.
[0026]
Example 8
In Example 1, mercury removal treatment was performed under the same conditions except that 0.07 part by weight of hydrogen sulfide gas was used instead of 2 parts by weight of an aqueous solution containing 700 ppm of hydrogen sulfide. The mercury concentration was 1 W / Vppb or less, and the mercury concentration in the condensate was 1 W / Vppb or less after standing for 3 weeks.
[0027]
Example 9
Place hydrogen sulfide gas 0.00014 parts by weight, condensate containing mercury of C / C ′ = 0 (mercury concentration 5 W / Vppb) 1000 parts by weight and 0.01 parts by weight of iron tetroxide in a carbon steel container, The mixture was stirred for 3 hours to remove mercury and left to stand. After standing, when the mercury concentration in the condensate excluding the solid was measured using a membrane filter having a pore diameter of 0.45 μm, it was 1 W / Vppb or less. Even if this was left for 3 weeks, the mercury concentration was 1 W / Vppb or less.
[0028]
Comparative Example 1
500 ml of condensate containing mercury was put in a carbon steel container, and gas of 21 vol% oxygen was blown in at 250 ml per minute for 1 hour. The value of C / C ′ at this time was 1.00.
In Example 1, mercury removal treatment was performed under the same conditions except that the condensate containing mercury of C / C ′ = 1 was used instead of the condensate containing mercury of C / C ′ = 0. It was 1 W / Vppb or less when the mercury concentration was measured after stirring for 3 hours and removing the mercury and leaving it still. After further standing, the mercury concentration in the condensate gradually increased from 21 hours later, and became 27 W / Vppb after 3 weeks. The time-dependent change in mercury concentration at that time is shown in FIG.
[0029]
【The invention's effect】
As described above in detail, according to the present invention, the mercury concentration of the liquid hydrocarbon containing mercury is efficiently reduced to 1 W / Vppb or less by a very simple means, and the mercury concentration is increased again. It can be suppressed.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between mercury concentration and time during which liquid hydrocarbons subjected to mercury removal treatment were allowed to stand in Example 1. FIG.
2 is a graph showing the relationship between the mercury concentration and the time during which liquid hydrocarbons subjected to mercury removal treatment were allowed to stand in Comparative Example 1. FIG.

Claims (1)

In removing mercury from liquid hydrocarbons containing mercury, liquid hydrocarbons containing dissolved oxygen that contains mercury and does not contain dissolved oxygen or is in equilibrium with a gas having an oxygen concentration of 8 vol% or less are (A ) A sulfur compound represented by the general formula MM ′S (M and M ′ are the same or different and each independently represents hydrogen, an alkali metal or an ammonium group), an aqueous solution containing the sulfur compound, or a crude oil tank. An aqueous solution containing hydrogen sulfide present, (B) A mercury removal method comprising contacting with the following substance having ionizing ability for a single mercury contained in the hydrocarbon to remove mercury.
Here, substances capable of ionizing single mercury are iron sulfate, iron chloride, iron oxide, iron nitrate, copper sulfate, copper chloride, copper oxide, copper nitrate, manganese compound, nickel compound, inorganic peroxide, organic One selected from peroxide and sludge present in crude oil tanks.

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