JPH03258340A - Method of storing carbon dioxide - Google Patents

Abstract

PURPOSE:To enable stable storage of a large amt. of carbon dioxide for a long time at rather low cost by storing carbon dioxide in a dissolved state in water in an underground layer of oil well or gas well. CONSTITUTION:CO2 recovered from exhaust gas or air is temporary reserved in a tank 1, and then introduced to a compressor 4 to be compressed. The compressed CO2 is added to water supplied from a water tank 3 through a pump 4, mixed in a mixer 5 so that a large amt. of CO2 is dissolved in water. This water with dissolved CO2 is sent under pressure through a gas well 6 which is used for gas mining, so that the water is injected from the lower end 7 of the well to the underground gas layer 8 to be stored in a stable state for a long time. The ejection pressure of the compressor 2 and the pump 4 and the mixing ratio of CO2 and water are determined according to the temp. and possible pressure of the underground layer to maintain.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a method for storing a large amount of carbon dioxide recovered from combustion gas, the atmosphere, etc., for the purpose of preventing global warming caused by carbon dioxide (CO2)K. Regarding.

[Conventional technology]

Conventionally, for industrial purposes, carbon dioxide has been temporarily stored on a relatively small scale in pressure vessels or made into dry ice. However, most of these carbon dioxides are released back into the atmosphere during industrial use, and it is not possible to store large amounts of carbon dioxide in a stable manner over a long period of time to prevent an increase in the concentration of carbon dioxide in the atmosphere. It wasn't.

[Problem to be solved by the invention]

The combustion of fossil fuels in power plants, general industrial boilers, etc. has increased the concentration of carbon dioxide in the atmosphere L7, and in recent years the global warming phenomenon known as the greenhouse effect has become a problem. Table 1 shows the amount of carbon dioxide generated at the source in Japan.

Currently, most of this large amount of carbon dioxide is released into the atmosphere.

Table i Cot generation amount (1986, estimated value) Thermal power generation Iron Steel General industry Transportation Transportation Agriculture Fisheries Civil and other Livelihoods and other CO total 100 tons, * 231, 1 125.5 180.6 158.0 20.9 137.6 60.0 920.1 25.1 13.6 19°6 17.2 2.9 15.0 6.5 100.0 To prevent the increase in the concentration of carbon dioxide in the atmosphere, In order to capture carbon without releasing it into the atmosphere or to store carbon dioxide after capturing it from the atmosphere, the conventional methods described above have problems such as the cost of storage containers and storage locations, and large amounts of carbon dioxide are It is not realistic to store carbon stably for a long time.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method for storing a large amount of carbon dioxide stably over a long period of time and at a relatively low cost.

[Means to solve the problem]

The carbon dioxide storage method of the present invention is characterized in that carbon dioxide is stored in a geological formation of a gas field or an oil field in a state in which carbon dioxide is dissolved in water.

[Effect]

Table 2 shows Henry's constants representing the solubility of carbon dioxide (COt) and CH in water.

From this table, it can be seen that the solubility of carbon dioxide in water is about 20 times or more that of CH4, which is large.

In the present invention, by utilizing this property and storing carbon dioxide in a large amount dissolved in water within the geological formations of gas or oil fields, it is possible to store carbon dioxide stably underground for a long period of time. can. Moreover, the usable volume of the geological formations in gas or oil fields is large, and it is possible to store large amounts of carbon dioxide.

In addition, gas fields or oil fields to be used in the present invention include those that are currently being mined, those that are depleted after mining, or those that are close to depletion status 11, as well as those that have voids in the strata before mining. It is possible to apply the present invention to gas fields or oil fields.

Furthermore, in order to make carbon dioxide dissolved in water in a gas field or oil field stratum, there are two methods: dissolving carbon dioxide in water on the ground and injecting it into the stratum 9, or dissolving water and carbon dioxide separately. A wide variety of methods can be employed, including a method in which carbon dioxide is dissolved in water in a geological formation, a method in which carbon dioxide is dissolved in a water layer existing in a geological formation, and the like.

〔Example〕

A first embodiment of the present invention will be explained using a ta1 diagram.

In this example, carbon dioxide is stored in a gas field without a water layer after gas extraction.

Carbon dioxide (Co) recovered from combustion gas, the atmosphere, etc.
t) Gas enters tank 1 for temporary storage and is sent to compressor 2. The compressed carbon dioxide gas is sent from the water tank 3, joins the water pumped by the pump 4, and is mixed in the mixer 5 to dissolve a large amount of carbon dioxide in the water. The discharge pressure of the compressor 2 and the pump 4 and the mixing ratio of carbon dioxide and water are set depending on the pressure and temperature that can be maintained in the underground layer. Water with a large amount of dissolved carbon dioxide passes through the gas field well 6 used during gas extraction, and is injected into the gas layer 8 in the underground layer from the injection part 7 at the bottom end of the gas field well 6, providing long-term stability. stored in

Note that 9 in the figure is the cap rock of the gas field.

A second embodiment of the present invention will be described with reference to FIG.

In this embodiment, carbon dioxide is dissolved and stored in a water layer in an underground layer of a gas field.

From a tank 11 that temporarily stores carbon dioxide gas recovered from combustion gas, atmospheric air, etc., carbon dioxide gas enters a compressor 12 where it is compressed. The compressed carbon dioxide gas passes through the gas field well 13 used during gas extraction, and flows from the injection part 17 at the lower end to the water layer 14 of the gas field.
The carbon dioxide is sent into the interior, dissolved in water, and stored in a stable manner for a long period of time. Note that 16 in the figure is a cap rock.

A third embodiment of the present invention will be explained with reference to FIG.

In this embodiment, carbon dioxide is stored in a water-soluble gas field.

The pressurized water 21 and carbon dioxide (CO,) gas 22 are
The gases are individually sent through an inner pipe 26 provided in the gas field well 25 and between the inner pipe 26 and the gas field well 25, respectively.

The lower end of the inner pipe 26 is located above the lower end of the gas field well 25, and a press-fitting part 23 is formed in the lower part of the gas field well 25 near the water-soluble gas layer 24. The carbon dioxide gas 22 is sent to this press-in part 23 through the inner pipe 26, where the carbon dioxide gas 22 is dissolved in water, and then
The water-soluble gas is injected into the water-soluble gas layer 24 under pressure. In this way, carbon dioxide is stably stored in the water-soluble gas layer 24 over a long period of time.

In this example, carbon dioxide is dissolved in water on the ground and then stuttered by being sent to the water-soluble gas layer.

〔Effect of the invention〕

The release of carbon dioxide into the atmosphere caused by the combustion of fossil fuels leads to global environmental destruction such as global warming, but by the method of the present invention, a large amount of carbon dioxide recovered from combustion gas and the atmosphere can be It can be stored relatively cheaply and stably over a long period of time in the strata of gas or oil fields, which can have a great effect on preventing global environmental destruction.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a first embodiment of the invention, FIG. 2 is an explanatory diagram of a second embodiment of the invention, and FIG. 3 is an explanatory diagram of a third embodiment of the invention. DESCRIPTION OF SYMBOLS 1...tank, 2...compressor, 3...water tank, 4...pump, 5...mixer, 6...gas field well 7...injection part, 8... Gas layer, 9... Cap rock, 11... Tank, 12... Compressor, 13.
...Gas field well 14...Water layer, 15...Gas layer, 1
6... Cap rock, 17... Press-fitting part, 21... Water, 22
... carbon dioxide gas, 24 ... water-soluble gas layer, 25
...Gas field well, 26...inner pipe. The first circle

Claims (1)

[Claims] A carbon dioxide storage method characterized by storing carbon dioxide dissolved in water in an underground layer of a gas field or oil field.