KR20070066137A - System for desalination by producing gas-hydrate or clathrate in gas phase and method thereof - Google Patents

Abstract

A noble seawater desalinating system and a noble seawater desalinating method that can efficiently separate components such as salt and contaminants in a gas phase gas-hydrate reactor for forming a mixture of seawater and gas, and can recycle the recovered heat value in a gas/liquid separation process by recovering heat value generated in a gas-hydrate production process are provided. A system for desalination of seawater by producing gas-hydrate in gas phase comprises: a gas-hydrate reactor(100) comprising seawater sprays(101) for spraying small particles of seawater into a gas layer, an ultrasonic vibration generator(102) for spraying non-reacted seawater again to convert the seawater into particles, a spray path(103) for moving the seawater particles into the gas layer, a heat exchanger(104) for absorbing heat of reaction of gas-hydrate by seawater, and gas ejectors(105) for uniformly diffusing gas into a concentrated seawater layer; a gas-hydrate separator(200) comprising a screw conveyor(201) for separating concentrated seawater from the gas-hydrate, a porous cylinder(202) through which the separated concentrated seawater flows, a concentrated seawater tank(203) for provisionally storing the concentrated seawater, and a scraper(204) for separating gas-hydrate compressed by the screw conveyor from the screw conveyor; and a gas-hydrate dissociation drum(300) in which a heat exchanger(301) and a baffle(302) are installed to separate gas and water from the gas-hydrate efficiently.

Description

System for Desalination by Producing Gas-Hydrate or Clathrate in Gas Phase and Method etc.

1 is a schematic block diagram showing a system for desalination of seawater by producing gas hydrate in a gas phase according to the present invention.

2 is a view showing a material resin according to an embodiment of the present invention for generating and desalination of gas hydrate of seawater using propane gas.

3 is a view showing a material resin according to an embodiment of the present invention for generating and desalination of gas hydrate of seawater using methane gas.

4 is a view showing a material resin according to an embodiment of the present invention for generating and desalination of gas hydrate of seawater using carbon dioxide gas.

* Brief description of the major symbols in the drawings *

1, 2, 3, 9, 10, 11, 12, 13: pipe

4, 5, 6, 7, 8: direction of mass movement

100 : gas hydrate reactor 101: sea water spray (spray)

102: ultrasonic vibration generator 103: spray furnace

104: heat exchanger 105: gas sparger

150: slide valve

200 : gas carb separator 201: screw conveyor (screw conveyor)

202: porous cylinder 203: scraper

300 : gas hydrate dissociation tank

301: heat exchanger 302: baffle

303: gas compressor

Field of invention

The present invention relates to a method for desalination of seawater by producing gas hydrates. More specifically, the present invention mixes the gas to the small particles of seawater through the liquid spray device to produce gas hydrate in the gaseous phase and then make the unreacted concentrated seawater spray by ultrasonic wave and then re-contact with the gas hydrate The present invention relates to a method for desalination of seawater by separating the final concentrated seawater and gas hydrate and gas. The present invention also includes a system for producing gas hydrates to desalination of seawater.

Background of the Invention

Since seawater contains various mineral components including salt, it is necessary to go through a desalination process to separate salts in order to use these components or to obtain fresh water as drinking water. Various methods of desalination of seawater have been proposed so far, and desalination facilities are installed and operated.

The oldest desalination methods include distillation using water phase change and reverse osmosis using reverse concentration. Distillation consumes a lot of energy because water requires a larger amount of heat source than other materials for phase change. Therefore, the desalination method by distillation method is economical but is mainly used in the Middle East, which is an energy surplus country. Desalination of seawater by reverse osmosis also requires additional treatment because seawater needs to be pretreated and high operating pressure is required. Therefore, this method can be seen as one step ahead of the distillation method in economics, but its limitations are revealed. In addition to these two methods, a recently developed method is a desalination method through a gas hydrate process. This method produces gas hydrates by mixing a gas capable of forming a hydrate with seawater to be desalted, and then separates gas and water, ultimately desalting seawater and separating condensates such as salts contained in the seawater. That's how.

One desalination method through a gas hydrate process is disclosed in US Pat. No. 6,158,239. This method relates to a method of injecting hydrocarbon gas such as methane gas into contaminated water or seawater to generate gas hydrate, and then separating gas and water to purify contaminated water or desalination of seawater.

Another desalination method through a gas hydrate process is disclosed in US Pat. No. 6,562,234. This method relates to a method of purifying contaminated water and a method of desalination of seawater that can inject gas into contaminated water or seawater to generate gas hydrates, and then separate gas and water to obtain cooling water.

The present inventor has developed a system for desalination of seawater by generating gas hydrate and has already filed a patent application as a patent application No. 2005-36013 (filed on Apr. 29, 2005). This patent application is a system for desalination of seawater by producing gas hydrates in a liquid phase, and it has been developed to develop the system of the present invention, considering that the yield will be very high if gas hydrates can be generated in the gas phase rather than the liquid phase.

The present inventors have remarkably improved the desalination method through the conventional gas hydrate process to form gas hydrate by reacting seawater liquid particles and gas in the gaseous state, and making unreacted seawater into small particles using ultrasonic waves, and then React to produce gas hydrates, and effectively separate gas hydrates and concentrated seawater using porous cylinders and screw conveyors, and use the heat of absorption and decomposition of gas hydrates to cool seawater and facilitate separation of gas and fresh water. The company is beginning to develop a new desalination system that can be compressed and reused.

It is an object of the present invention to provide a system in which hydrates of seawater and gas are formed in the gas phase in a method of desalination of seawater through a gas hydrate process.

It is another object of the present invention to efficiently separate components such as salts or contaminants in a gas phase reaction system in which sea water and gas hydrates are formed in the gas phase and a separation system for separating hydrates and concentrated sea water, It is to provide a new desalination system and method for facilitating separation from seawater.

Another object of the present invention is to maximize the efficiency of gas hydrate generation by generating gas hydrate in the gas phase to maximize the recovery rate of fresh water generated in this process, and to simplify the separation process and maximize the efficiency through the mechanical separation process. It is to provide a desalination system and method thereof.

The above and other objects of the present invention can be achieved by the present invention described below.

Summary of the Invention

The desalination system of the present invention is installed in the upper part of the reaction tank for efficient contact between the gas and seawater in the gas phase seawater spraying device 101 for spraying seawater with small particles in the gas layer, ultrasonic waves for re-spraying unreacted seawater Vibration generating device 102, spraying furnace 103 for moving the granulated seawater to the gas layer, heat exchanger 104 flowing seawater installed on the outside of the spraying furnace to absorb the reaction heat of the gas hydrate, and concentrated seawater A gas hydrate reactor (100) including a gas injection device (105) disposed below the reactor for dispersing the gas evenly into the concentrated seawater layer for effective contacting and diffusion of the gas; Screw conveyor 201 for separating gas hydrate and concentrated seawater generated in the reaction tank, porous cylinder 202 through which the separated concentrated seawater passes, and concentrated seawater tank for temporarily storing concentrated seawater passing through the porous cylinder 203, and a gas hydrate separator comprising a scraper 204 for separating the gas hydrate compressed by the screw conveyor from the screw conveyor; In addition, a heat exchanger 301 and a baffle 302 are installed inside the gas hydrate decomposition tank 300 for efficiently separating gas and water from the gas hydrate.

The gas separated from the gas hydrate decomposition tank 300 is compressed by the gas compressor 303 and resupplied to the gas hydrate reaction tank 100.

A slide valve 150 is installed to adjust the flow rates of the gas hydrate and the concentrated seawater flowing from the gas hydrate reactor 100 to the gas hydrate separator 200.

The seawater spray device 101 installed in the gas hydrate reaction tank 100 of the present invention makes the seawater into small particles and sprays the gas layer present in the gas phase reaction to maximize the gas-liquid contact surface to maximize gas hydrate formation in a short time. It is characterized by that.

The gas hydrate and the unreacted concentrated seawater generated in the gas hydrate reaction tank are collected in the lower part of the reactor, and the ultrasonic hydrate generator 103 makes the liquid of the unreacted seawater into small particles to make the gas hydrate reactor through the spray furnace 102. Spray into the gas layer to maximize the gas-liquid contact surface to maximize gas hydrate formation in a short time.

In the desalination method of the seawater according to the present invention, the gas hydrate and the concentrated seawater at the bottom of the reaction tank are transferred to the screw conveyor 201 which is a solid-liquid separation device through the slide valve 150, and the liquid is screwed in the porous cylinder 202. The gas hydrate decomposing tank 300 is introduced into the concentrated seawater tank 203 and discharged, and the gas hydrate is transferred to the screw pressure and removed by the scraper 204 installed at the end of the screw conveyor. The liquid is naturally liquefied to be fresh water, and the gas is supplied into the reactor through the gas injector 105 installed in the reactor 100 through the gas compressor 303.

Hereinafter, with reference to the accompanying drawings, the contents of the present invention will be described in detail.

Detailed Description of the Invention

The present invention relates to a method and system for efficiently desalination of seawater by mixing gas into granulated seawater to generate gas hydrates in the gas phase, and then separating the liquid water and gaseous gas.

1 is a schematic block diagram showing a system for desalination of seawater by generating gas hydrates in the thalamus according to the present invention.

The desalination system of seawater according to the present invention is a gas hydrate separation apparatus including a gas hydrate reaction tank 100 installed vertically as shown in FIG. 1, and a screw conveyor 201 which is a horizontally installed solid-liquid separator ( 200, and a gas-hydrate decomposition tank 300 that separates gas and fresh water from the gas hydrate. Capacity such as diameter or height of the reaction tank and the hydrate decomposition tank may be determined according to the treatment capacity of the sea water, which can be easily carried out by those skilled in the art.

First, the seawater to be treated is passed through a heat exchanger 104 installed inside the gas hydrate reaction tank 100 through the pipe 1 to absorb the heat of reaction generated during the gas hydrate reaction to maintain a constant temperature inside the reaction tank and heat The absorbed sea water passes through a heat exchanger 301 installed inside the gas hydrate decomposition tank 300 through the pipe 2, and supplies heat necessary for gas-hydrate decomposition and returns to the initial temperature of sea water. This seawater is made into small liquid particles by the seawater spray device 101 through the pipe 3 and sprayed into the gas phase layer filled with the gas in the gas hydrate reactor 100. Some of the sprayed liquid particles react with the gas to form gas hydrates and some are collected in the lower part of the reactor as it is along the direction of travel (4).

Some of the liquid collected in the lower part of the reactor generates liquid particles by using the ultrasonic vibration generating device 102 to increase the recovery rate of desalination and flows into the gas layer through the spray path 103 along the moving direction 5. The sprayed liquid particles are reacted with the gas to form gas hydrates. The spray furnace has a structure in which the funnel is upside down, and an umbrella-shaped cover is fixed on the upper portion thereof to allow the liquid particles to easily move into the gas layer, and such a structure has a general knowledge in the art to which the present invention pertains. It can be easily carried out by.

The gas hydrate formation reaction is an exothermic reaction, and heat generated at this time is removed by initial seawater passing through the heat exchanger 104 installed inside the gas hydrate reaction tank 100 so that the gas hydrate formation reaction is not inhibited due to the temperature rise. .

In the screw conveyor 201, which is a solid-liquid separator, a gas hydrate and concentrated seawater mixture is introduced through the slide valve 150 along the direction of movement 6, and the screw conveyor is a gas hydrate and concentrated seawater under pressure by mechanical rotation. The concentrated seawater is temporarily stored in the concentrated seawater tank 203 through the porous cylinder 109 surrounding the screw conveyor to the outside in the movement direction 7. The concentrated seawater temporarily stored in the concentrated seawater tank 203 is discharged along the pipe 11 and recycled. The gas hydrate remaining inside the screw conveyor is separated by the scraper 204 installed at the screw conveyor end and moved to the gas hydrate decomposition tank 300 along the moving direction 8.

In the gas hydrate decomposition tank 300, the pressure is operated lower than those of the apparatuses so that the gas hydrate is naturally decomposed into gas and water. The heat exchanger 301 is installed inside the gas hydrate decomposition tank 300 so that the initial seawater heated in the gas hydrate reaction tank passes along the pipe 2 to supply heat for the endothermic reaction during gas hydrate decomposition and the sea water itself. Is cooled and supplied to the seawater spraying device 101 along the pipe 3.

The gas separated from the water is compressed using a gas compressor 303 along the pipe 9 to a pressure required for gas hydrate formation, and then a gas injector installed below the gas hydrate reactor 100 along the pipe 10. Through 105). Pure water separated from the gas is discharged to the outside through the pipe 12 beyond the baffle 302 installed in the gas hydrate decomposition tank 300.

In order to control the pressure in the reactor 100, a pipe 13 in which the automatic valve 20 is installed may be provided at an upper portion thereof.

Gases used to generate gas hydrates in the present invention include hydrocarbon gases such as methane, propane and the like, and gases such as carbon dioxide. Gases for forming gas hydrates or clathrates can be readily carried out by those skilled in the art.

Gases used to generate gas hydrates are known to be gaseous under at least 100 types of atmospheric conditions, and are known to have different crystal structures depending on the type of gas. In addition, depending on the type of gas, the temperature and pressure conditions under which the gas hydrate is formed vary, and thus, both the forming material and the energy balance are different. CH ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₄ H ₁₀ , O ₂ , H ₂ , N ₂ , CO ₂ , H ₂ S, Cl ₂ , CH ₃ Cl, C ₃ H ₆ , CH ₃ CCl ₂ There are various kinds of gas hydrate formers such as F, CH ₃ CClF ₂ , CH ₃ CHF ₂ , CHClF ₂ , CH ₂ ClF, SF ₆ , CF ₄ , LNG and the like. If there is no environmental problem, no toxicity, no flammability, it is safe under atmospheric conditions, it is inexpensive, its operating temperature and pressure are appropriate, and there is no problem in the selection of materials in contact with the gas. desirable. Most gases, however, did not meet one or two of these selection criteria.

In addition, the crystal structure of the gas hydrate is different depending on the type of the gas forming agent. When the diameter of the former gas molecule is small, a gas hydrate of structure-I is formed, and a larger gas hydrate is formed of structure-II, structure-H, or the like as the molecule becomes larger. CO ₂ , H ₂ S, CH _4, etc. are in structure-I form, R141b (Dichloromonofluoroethane, CCl ₂ FCH ₃ ) is in structure-II form, and propane forms a structure-II form hydrate. Therefore, depending on the structure and size of the hydrate formed, the method of washing, the separation method from the concentrated salt water, etc. are all different. Gas hydrates that are too small are quite difficult to clean and separate from seawater and have a relatively high salt concentration of pure water obtained. The best gas hydrate size for subsequent work is 250-400 μm.

In addition, depending on the type of forming agent gas used, the density of the gas hydrate is lower than that of seawater, which has a positive buoyancy and the gas hydrate moves upwards. In each case, the subsequent devices and operations for obtaining pure water are also different. A typical case there is a CH ₄ and CO _2, in the case of CH ₄ rises continuously up to the amount by which the density of the gas hydrates is lower than sea water buoyant, in the case of CO _2, the density of the gas hydrate is higher than sea water gas hydrate is below the sea water Sink.

In the present invention, LNG, LPG, R141b, H ₂ S or CO ₂ is used as the forming gas. The reason these gases are used is because, firstly, LNG and LPG are the most commonly obtained around us, and R141b has the fewest drawbacks except that it has ozone depletion index as the forming gas. ₂ or H ₂ S is because the purpose of removing CO ₂ and H ₂ S at the same time affecting the environment and the purpose of desalination.

The desalination method and system of the present invention can of course be applied to desalination of seawater, but can also be applied almost intact to purification of contaminated water.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example 1

In Example 1, gas hydrate was produced using propane gas. 2 is a view showing a material resin according to the present embodiment for generating and desalination of gas hydrate of seawater using propane gas. A 3.5 wt% NaCl solution at 4 ° C. was prepared and injected at a rate of 480 g / hr. Propane gas was initially used with 0.07 kg injected and recycled. The gas hydrate mixer was operated at 4.5 kg / cm ² g and propane gas formed gas hydrate of structure-II.

Example 2

In Example 2, gas hydrate was produced using methane gas. 3 is a view showing a material resin according to the present embodiment for generating and desalination of gas hydrate of seawater using methane gas. A 3.5 wt% NaCl solution at 4 ° C. was prepared and injected at a rate of 480 g / hr. Methane gas was initially injected with 0.06 kg and recycled to continue use. The gas hydrate mixer was operated at 40 kg / cm ² g and methane gas formed gas hydrate of structure-I.

Example 3

In Example 3, carbon dioxide was used to produce gas hydrate. 4 is a view showing a material resin according to the present embodiment for generating and desalination of gas hydrate of seawater using carbon dioxide. A 3.5 wt% NaCl solution at 4 ° C. was prepared and injected at a rate of 480 g / hr. Carbon dioxide gas was initially used by continuously injecting and recirculating 0.15 kg. The gas hydrate manufacturing apparatus was operated at 25 kg / cm ² g and the carbon dioxide gas formed gas hydrate of structure-I.

In the method of desalination of seawater through a gas hydrate process, the present invention can efficiently separate components such as salts or contaminants in a gaseous gas hydrate reaction tank in which a mixture of seawater and gas is formed, and The invention has the effect of providing a new desalination system and method for recovering calories and recycling during gas / liquid separation.

Simple modifications and variations of the present invention can be readily used by those skilled in the art, and all such variations or modifications can be considered to be included within the scope of the present invention.

Claims (8)

Sea water spraying device 101 for spraying sea water into small particles in the gas layer by installing on the inside of the reactor, ultrasonic vibration generating device 102 for re-spraying unreacted sea water to make particles, and moving the granulated sea water to the gas layer Spray furnace 103, a heat exchanger 104 in which seawater is installed on the outside of the spray furnace to absorb the heat of reaction of gas hydrate, and gas into the concentrated seawater layer for effective contact and diffusion of concentrated seawater and gas. A gas hydrate reactor (100) including a gas injection device (105) installed below the reactor to diffuse evenly; Screw conveyor 201 for separating gas hydrate and concentrated seawater generated in the reaction tank, porous cylinder 202 through which the separated concentrated seawater passes, and concentrated seawater tank for temporarily storing concentrated seawater passing through the porous cylinder 203, and a gas hydrate separator comprising a scraper 204 for separating the gas hydrate compressed by the screw conveyor from the screw conveyor; And A heat exchanger 301 and a baffle 302 disposed therein, the gas hydrate decomposition tank 300 for efficiently separating gas and water from the gas hydrate; Desalination system of seawater through the efficient contact of gas and seawater in the gas phase, characterized in that consisting of. The desalination system of seawater according to claim 1, wherein the gas separated in the gas hydrate decomposition tank (300) is compressed by a gas compressor (303) and resupplied to the gas hydrate reaction tank (100). The desalination of seawater according to claim 1, wherein a slide valve (150) is installed to adjust the flow rates of the gas hydrate and the concentrated seawater flowing from the gas hydrate reaction tank (100) to the gas hydrate separating apparatus (200). system. Injecting gas into the gas hydrate reactor 100 and compressing the gas to a predetermined pressure; Spraying seawater into the gaseous gas phase layer with small particles through a seawater spray device into the gas hydrate reactor; Unreacted seawater collected in the lower part of the gas hydrate reactor is made into small particles using an ultrasonic vibration generator, and sprayed into the gaseous gas phase layer through a spray furnace; Injecting gas into the gas hydrate reactor by using a gas injector installed below the reactor; And Separating the gas hydrate and the concentrated seawater formed in the gas hydrate reactor into a screw conveyor installed inside the porous cylinder to separate the gas hydrate and the concentrated seawater; Desalination method of seawater, characterized in that consisting of steps. The gas hydrate separated from the screw conveyor is transferred to a gas hydrate decomposition tank, and endothermic reaction heat generated during decomposition using a heat exchanger installed therein is supplied from initial seawater, and the initial seawater is cooled to decompose into gas and water. Desalination method of seawater, characterized in that it further comprises a step. The seawater absorbed by the heat of reaction in the heat exchanger (104) installed in the gas hydrate reactor and the decomposition heat provided by the gas hydrate decomposition tank is transferred to the gaseous gas layer by small particles through the seawater spray device (101). The desalination method of seawater characterized by spraying. The method of claim 5, wherein the gas separated from the gas hydrate decomposition tank further comprises the step of compressing to the pressure required for operation through a gas compressor and supplying to the gas hydrate reaction tank through a gas injector Method of desalination of seawater. The method of claim 4, wherein the gas generating the gas hydrate is CH ₄ , C ₂ H ₆ , C ₃ H ₈ , C ₄ H ₁₀ , O ₂ , H ₂ , N ₂ , CO ₂ , H ₂ S, Cl _2. , CH ₃ Cl, C ₃ H ₆ , CH ₃ CCl ₂ F, CH ₃ CClF ₂ , CH ₃ CHF ₂ , CHClF ₂ , CH ₂ ClF, SF ₆ , CF ₄ , and LNG gas Seawater desalination method

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