KR20100022700A - Formation process of sf6 gas hydrate using generating promoter - Google Patents

Abstract

PURPOSE: A method for forming sulfur hexafluoride gas hydrate using a forming promoter is provided to form the SF6 hydrate with high efficiency and high concentration without a promotion of temperature and pressure falling using an anionic surfactant as a promoter. CONSTITUTION: A method for forming of SF6 hydrate includes a step of forming the SF6 hydrate using a formation principle of gas hydrate. An aqueous solution in which the anionic surfactant is added contacts with the SF6 in the step of forming the SF6 among a separation and retrieving process of SF6. A concentration of the added anionic surfactant is 0.01 ~ 5 wt%. The anionic surfactant is sodium dodecyl sulfate or a linear alkyl benzene sulfonate.

Description

Formation process of SF6 gas hydrate using generating promoter

The present invention relates to a method for forming a gas hydrate of SF ₆ using an anionic surfactant as a hydrate formation accelerator, which can be used in the technical field for separating and recovering SF ₆ using the gas hydrate generation principle.

SF ₆ is a compound consisting of fluorine (F) and sulfur (S), also referred to as sulfur hexafluoride. SF ₆ has been known for its excellent insulation since its discovery in 1900 and has been used extensively as an electrical insulator since. SF ₆ is an inert, odorless, non-toxic gas under normal conditions and does not decompose up to 500 ° C. Insulation is about 2.5 times higher than that of air, and at 3 atmospheres, it has the same dielectric strength. SF ₆ is heavier than air, but it is only 1/140 of insulating oil, which is a big advantage in miniaturization and lightening of power equipment. Sulfur hexafluoride (SF ₆ ) has excellent insulation and arc-extinguishing properties, so it can be used as insulating gas for power transformers, cleaning gas for semiconductor and liquid crystal plasma CVD, and covering gas for foundries. (covering gas). In particular, in Korea, since semiconductors and liquid crystal plasmas occupy a core position in the electrical and electronics industry, the amount of SF ₆ necessary for the manufacturing process is absolutely higher than in other countries.

However, SF ₆ has a high global warming index and a very long life, and together with carbon dioxide (CO ₂ ), methane (CH ₄ ), nitrous oxide (N ₂ O), hydrogen fluorocarbon (HFC _S ) and perfluorocarbon (PFC _S ) It is also a representative environmental pollutant that is designated as one of the six global warming gases. In particular, SF ₆ has the highest global warming influence among the six global warming gases, and is considered to be the most serious environmental pollutant because the global warming index is 23,400 times higher than carbon dioxide, a representative global warming gas.

In addition, all countries were included as targets for greenhouse gas reduction after 2013, according to the climate agreement adopted by the 13th UN Climate Change Conference on 15 December 2007. Therefore, Korea will be included in the mandatory reduction country in 2013, and it is in a position to make concrete greenhouse gas reduction efforts. Therefore, it is urgent to find an economical and efficient new alternative to the separation and recovery of SF ₆ which causes serious greenhouse gas effects. It is in the situation.

Currently, low temperature distillation, adsorption using a solid adsorbent, and absorption using a liquid absorbing solution are mainly used as a method of separating and recovering all kinds of gases as well as SF ₆ , but these processes require enormous energy costs. There are disadvantages. Therefore, research on the emergence of a low energy consumption process in the process of separating specific components from multi-component mixed gas continues. For example, US Pat. No. 5,700,311 discloses a process for selectively separating carbon dioxide from a multicomponent mixed gas using gas hydrates. However, this process has problems such as slow reaction rate, low reaction amount, high hydrate production pressure condition, and the situation for practical use thereof has been pointed out. In addition, Korean Patent No. 10-0347092 discloses a technique for promoting the formation of a gas hydrate by adding a substance such as tetrahydrofuran (THF) having an effect of promoting pressure drop.

On the other hand the separation and recovery of SF ₆ method applying the principles of the formation of SF ₆ hydrate form of the SF ₆ hydrate is pressure and temperature conditions than the other gas (when one 276.5K, 0.2MPa) without promoting the pressure drop due to the low There is an advantage that can be produced in plain forming conditions. However, the formation of the hydrate of SF ₆ has a problem in that the separation, recovery of the practical use is limited due to the long reaction time and low production amount.

It is an object of the present invention to provide a high efficiency, high concentration SF ₆ hydrate formation method using an anionic surfactant as a promoter to solve the above-mentioned problems.

It is another object of the present invention to provide the temperature and pressure at which high efficiency, high concentration of SF ₆ hydrate is formed, and the type and concentration of anionic surfactant as a promoter.

According to a preferred embodiment of the present invention to achieve the above object,

In the step of forming SF ₆ hydrate in the process of separating and recovering SF ₆ using the formation principle of gas hydrate, there is provided a method of forming SF ₆ hydrate, characterized in that the aqueous solution to which an anionic surfactant is added is contacted with SF ₆ . .

 It is preferable to add the anionic surfactant as 0.01-5 wt%.

 The anionic surfactant is preferably sodium dodecyl sulfate (SDS, Fluka) or linear alkyl benzenesulfonate (Linear Alkyl Benzene Sulfonate, LABS, Aldrich).

To the formation of SF ₆ hydrate compared to form a SF ₆ hydrate in the present invention by creating a SF ₆ hydrate by using an aqueous solution containing from 0.01 to 5wt% of an anionic surface active agent, pure water (pure water) is configured as described above, This allows for efficient gas consumption with high hydrate formation in a short reaction time without promoting temperature and pressure drop. This indicates that the effect of capturing a larger amount of SF ₆ in SF ₆ hydrate can be derived. As a result, the process for forming SF ₆ hydrate according to the present invention makes it possible to implement an economical and practical method for separating and recovering SF ₆ gas, which is a serious global warming material.

Hereinafter, the configuration and the embodiment of the present invention will be described in detail with the accompanying drawings.

The present invention method for forming a SF ₆ hydrate, comprising a step in the forming of SF ₆ hydrate of the separation and recovery process of the SF ₆ with the forming principles of the gas hydrate, contacting the anionic surface active agent is an aqueous solution of the SF ₆ added To provide.

Separation and recovery process of SF ₆ using the gas hydrate formation principle is proposed in Korean Patent Application No. 10-2007-111597 of the present inventors as an alternative to the conventional method for separating and recovering high energy consumption SF ₆ . It refers to a method of high-density concentration of SF6 in the form of gas hydrate while controlling temperature and pressure. In order to realize this method, a gas hydrate generation and decomposition apparatus of Korean Patent Application No. 10-2006-0117063 is used. A schematic device diagram is shown in FIG. 1.

Normally, gas hydrates have a space called cavity in a three-dimensional lattice structure formed by hydrogen bonds between water molecules under high pressure and low temperature conditions, and gas is physically trapped in the pores. One of the most commonly known gas hydrates is methane hydrate. When methane is reacted with water to form a hydrate, a high atmospheric pressure of about 20 atm is usually required at 4 ° C. However, in the case of SF ₆ to be separated in the present invention, even at room temperature, crystallization proceeds under relatively easy conditions of about 3.5 atmospheres. Therefore, the separation and recovery process using the gas hydrate formation principle as a method of separation and recovery of low energy type SF ₆ is very economical and appropriate.

The separation and recovery of SF ₆ using the gas hydrate formation principle is divided into 1) the formation of SF ₆ hydrate and 2) the decomposition step. The present invention relates to the formation of a gas hydrate, which is an electron.

It is brought into contact with the pure water and SF ₆ under the formation pressure and temperature conditions of the hydrate of the general method of SF ₆ SF ₆ When forming a hydrate, 2 and the separation and recovery process of Figure that the reaction time is too long, as shown in the third addition SF using the forming principles of the gas hydrate there is a very small amount of matter amount that formed even if the reaction time for a long period of time ₆ Although the economic utility is very high, it is difficult to commercialize. Therefore, in order to improve this, in the present invention, an anionic surfactant was added as a promoter of SF ₆ hydrate formation to realize a breakthrough formation speed and an increase in the amount of formation.

At this time, the anionic surfactant is an activator in which the anion part exhibits surface activity by ion dissociation in an aqueous solution. It is the most important hydrophilic group of anionic surfactant, and there are three kinds of carboxylic acid, sulfate ester, and sulfonic acid present in many products. As the gas hydrate formation accelerator of the present invention, a wide range of anionic surfactants can be used. Preferably, sulfonate-based anionic surfactants having excellent stability such as hard water resistance, hydrolysis resistance, and salt resistance can be used. As the sulfonate-based anionic surfactant, a general sulfonate salt such as alkyl sulfonate, alkylbenzene and alkylamino acid salt, alkylnaphthalene sulfonate salt, sulfo pumpkin salt and the like can be used. More preferably sodium dodecyl sulfate (SDS, Fluka) or linear alkylbenzenesulfonate (Linear Alkyl Benzene Sulfonate, LABS, Aldrich) can be used.

The anionic surfactant is added to pure water to prepare an aqueous solution, it is preferable to add in a concentration range of 0.01 ~ 5wt%. More preferably, it can be added in a concentration range of 0.01 ~ 0.5wt%. If the concentration is less than 0.01wt%, the addition amount is too small to sufficiently express the effect of improving the formation rate, and if the concentration is more than 5wt%, the excess surfactant causes the pupil of the three-dimensional lattice structure of the water molecule ( Cavity itself can be trapped rather than inhibit the formation of SF ₆ hydrate. Of course, since the essence of the present invention is in the addition of the surfactant itself, the addition of a surfactant of less than 0.01wt%, but more than 5wt% does not render the practice of the invention impossible.

Contacting SF ₆ with an aqueous solution to which an anionic surfactant has been added is for formation of a hydrate through gas / liquid contact, which is made in a vessel under constant pressure and temperature conditions, and may be accompanied by stirring for active contact. According to a preferred embodiment, SF ₆ is contacted with an aqueous solution to which an anionic surfactant is added in the hydrate reactor 8 of FIG. 1.

The present invention can be better understood by the following examples and experimental examples, it will be apparent to those skilled in the art that the present invention is not limited by these examples and experimental examples.

[Comparative Example 1] generated SF ₆ hydrate for the pure water (pure water)

Inject 100 ml of pure water into the reactor used in the present invention and repeat the flushing process of filling and releasing SF ₆ gas into the container three times or more, and then 0.38 to 0.78 MPa under hydrate formation conditions. The pressure in the range and the temperature of the aqueous solution were set to 275.2 ~ 276.2K conditions.

[Example 1] Preparation of SF ₆ hydrate promote aqueous solution containing SDS

In the same manner as in Comparative Example 1, but an aqueous solution containing sodium dodecyl sulfate (SDS, Fluka) was prepared according to the concentration and thoroughly mixed with sodium dodecyl sulfate (SDS, Fluka) Was injected to dissolve completely in water.

[Example 2] Preparation of SF ₆ hydrate aqueous solution containing facilitate LABS

  In the same manner as in Comparative Example 1, an aqueous solution containing linear alkyl benzenesulfonate (Linear Alkyl Benzene Sulfonate, LABS, Aldrich) was prepared according to the concentration and thoroughly mixed with a linear alkyl benzene sulfonate (Linear Alkyl Benzene Sulfonate, LABS, Aldrich) was injected to completely dissolve in water.

Experimental Example 1 produced SF ₆ hydrate containing SDS

In the above experiment, SF ₆ hydrate formation efficiency of the sodium dodecyl sulfate (SDS, Fluka) aqueous solution prepared in Comparative Example 1 and Example 1 was measured. Inject 100 ml of sodium dodecyl sulfate (SDS, Fluka) aqueous solution into the 660 ml reactor, and repeat the freshing process of filling and releasing SF ₆ gas into the vessel three times or more, followed by 0.78 MPa, The temperature of the aqueous solution containing sodium dodecyl sulphate (SDS, Fluka) aqueous solution was set to 276.2K and analyzed the SF ₆ hydrate formation rate over time.

[Example 2] generated SF ₆ hydrate containing LABS

In the experiment, SF ₆ hydrate formation efficiency of the linear alkylbenzenesulfonate (Linear Alkyl Benzene Sulfonate, LABS, Aldrich) aqueous solution prepared in Comparative Example 1 and Example 2 was measured. After injecting 100 ml of LABS aqueous solution into 660 ml reactor and repeating the freshing process of filling and releasing SF ₆ gas into the vessel three times or more, the temperature of the aqueous solution containing 0.78 MPa and LABS was hydrate forming condition at 276.2 K. Was set and the rate of SF ₆ hydrate formation over time was analyzed.

1 is a cross-sectional view showing the configuration of an embodiment of a gas hydrate generation and decomposition apparatus used in the present invention,

Figure 2 is a graph showing the SF ₆ hydrate formation according to the SF ₆ hydrate form and the sodium dodecyl sulphate concentration silsul (Sodium Dodecyl Sulfate, SDS, Fluka ) for pure water.

In addition, Figure 3 is showing a SF ₆ hydrate formation according to the SF ₆ hydrate formation and linear alkyl benzene sulfonate levels (Linear Alkyl Benzene Sulfonate, LABS, Aldrich) for the purified water graph.

As can be seen in Figures 2 and 3, when forming SF ₆ hydrate in pure water of Comparative Example 1, the consumption of SF6, that is, the amount of SF ₆ hydrate produced is 0.02 mol or less even if time passes. Formation rate is very slow. However, when anionic surfactants such as Sodium Dodecyl Sulfate (SDS, Fluka) and Linear Alkyl Benzene Sulfonate (LABS, Aldrich) were added as promoters, the concentration was different. Over time, the consumption of SF6, that is, the production of SF6 hydrate, increases proportionally. That is, the experiment according to the present invention was found to be a high-efficiency, high concentration of SF ₆ hydrate formation.

1 is a gas hydrate kinetic device diagram used in the present invention.

Figure 2 is a graph showing the results of SF ₆ hydrate kinetic experiments according to sodium dodecyl sulfate (SDS, Fluka) addition concentration in SF ₆ hydrate experiments applied to the present invention.

3 is a graph showing the results of SF ₆ hydrate kinetic experiments according to the concentration of addition using a linear alkylbenzenesulfonate (LABS, Aldrich) as a gas hydrate promoter (promoter).

<Description of the symbols for the main parts of the drawings>

1: gas supply

2: regulator

3: control valve

4: control valve

5: supply bass

6: micro flow control valve

7: Actuator

8: hydrate reactor

9: hydrate outlet valve

10: discharge valve

11: discharge valve

12: safety valve

13: temperature sensor

14: discharge valve

15: external pressure gauge

Claims (4)

In the formation steps of SF ₆ hydrate of the separation and recovery process of the SF ₆ with the principles of the gas hydrate formation, A method for forming SF ₆ hydrate, comprising contacting SF ₆ with an aqueous solution to which an anionic surfactant has been added. The method according to claim 1, negative ion concentration of the surface active agent is 0.01 to forming method of the SF ₆ gas hydrate which comprises adding to a 5 wt%. The method according to claim 1, the anionic surfactant is sodium dodecyl sulfate silsul forming method of the SF ₆ gas hydrates, characterized in that (Sodium Dodecyl Sulfate, SDS, Fluka). The method according to claim 1, wherein the anionic surfactant is a linear alkylbenzenesulfonate (Linear Alkyl Benzene Sulfonate, LABS, Aldrich), characterized in that the formation of SF ₆ gas hydrate.

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