KR101399442B1 - Apparatus for liquefaction and underground injection of carbon dioxide - Google Patents

Abstract

The present invention relates to an apparatus for a liquefaction and underground injection of carbon dioxide. The apparatus for the liquefaction and underground injection of carbon dioxide according to the present invention comprises: a supply part which supplies carbon dioxide; a compressor which compresses the carbon dioxide supplied from the supply part with high pressure and high temperature; a cooling device which cools the carbon dioxide passing through the compressor; a liquid-vapor separator which separates the carbon dioxide passing through the cooling device into vapor phase carbon dioxide and liquid phase carbon dioxide; and an injection part which includes an injection pump injecting the liquid phase carbon dioxide into the ground by compressing the liquid phase carbon dioxide passing through the liquid-vapor separator, and a heater heating the carbon dioxide passing through the injection pump in the supercritical state in order to inject the liquid phase carbon dioxide passing through the liquid-vapor separator into the ground by changing the liquid phase carbon dioxide into the supercritical state. The apparatus for the liquefaction and underground injection of carbon dioxide is characterized by re-supplying the vapor phase carbon dioxide passing through the liquid-vapor separator to the compressor and re-compressing the vapor phase carbon dioxide. Accordingly, the present invention provides the apparatus for the liquefaction and underground injection of carbon dioxide capable of reducing energy required for underground injection and energy for the liquefaction of carbon dioxide.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbon dioxide liquefaction apparatus,

The present invention relates to a carbon dioxide liquefaction and underground injection apparatus, and more particularly, to a carbon dioxide liquefaction and underground injection apparatus for liquefying carbon dioxide for transportation, To an underground injection device.

Carbon dioxide is the biggest contributor to global warming. Carbon dioxide is included in many gases emitted from coal-fired thermal power plants and iron ore-based steelworks.

Although the global warming index of carbon dioxide is lower than other greenhouse gases, it is classified as greenhouse gases, which account for about 80% of total greenhouse gas emissions and are also very important in terms of regulating emissions.

In order to prevent the global warming phenomenon as much as possible, it is necessary to reduce the amount of carbon dioxide released into the atmosphere by collecting and storing the generated carbon dioxide in a separate place do.

Carbon dioxide storage technologies that permanently or semi-permanently isolate carbon dioxide are being developed, and carbon dioxide can be stored in the ocean, in the ground, or on the ground.

Marine storage is expected to be able to store the carbon dioxide generated in the future for 500 years by spraying at below 3000m below sea level. However, there are problems prohibited under international law due to the stability problem such as ecosystem problem and acidification of the ocean. Carbon dioxide, such as potassium, is chemically stored by reacting with additive minerals, but there are problems such as excessive processing cost and cost of processing the produced material after completion.

Recently, a lot of researches have been carried out to store carbon dioxide in the ground.

Carbon dioxide is the most dense at the triple point, ie -56.3 ° C and 5.17 bar, so it is generally transported in the vicinity of the triple point. In the case of carbon dioxide in the gas phase, it is liquefied and transported with liquid carbon dioxide. Converts and injects into the ground.

At this time, it takes considerable energy to cool down the carbon dioxide to liquefy, and also consumes a considerable amount of energy to heat the supercritical state at a high pressure for the purpose of underground injection. In order to liquefy and store carbon dioxide for environmental preservation, So that there is a problem.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve such conventional problems, and it is an object of the present invention to provide a carbon dioxide liquefaction apparatus capable of liquefying carbon dioxide for transportation and carbon dioxide And an underground injection device.

This object is solved according to the present invention by a supply system comprising: a supply part for supplying carbon dioxide; A compressor for compressing the carbon dioxide supplied from the supply unit to a high pressure and a high temperature; A cooler for cooling the carbon dioxide that has passed through the compressor; A gas-liquid separator for separating the carbon dioxide passed through the cooler into carbon dioxide in gas phase and carbon dioxide in liquid phase; Liquid separator for converting the liquid carbon dioxide passed through the gas-liquid separator into a supercritical state and injecting the liquid carbon dioxide passed through the gas-liquid separator into the ground, Liquid separator, and an injector including a heater for heating the carbon dioxide to a supercritical state, wherein the gas-phase carbon dioxide having passed through the gas-liquid separator is supplied again to the compressor and is recompressed. Device.

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The injection unit may further include a pressurizing pump that pressurizes the liquid carbon dioxide to a predetermined pressure and supplies the carbon dioxide to the injection pump so that cavitation does not occur.

The apparatus may further include a heat exchanger for exchanging heat between carbon dioxide that has passed through the injection pump and carbon dioxide that has passed through the compressor.

Further, the heat exchanger may be located on the carbon dioxide flow path between the injection pump and the heater.

According to the present invention, it is possible to reduce the energy required for liquefying carbon dioxide by re-supplying the gaseous carbon dioxide passed through the gas-liquid separator to the compressor.

Further, by adopting the injection section provided with the injection pump and the heater, the carbon dioxide can be made into the supercritical state more easily and injected into the ground.

In addition, the injection section includes a pressurizing pump to prevent the occurrence of cavitation.

Further, by employing a heat exchanger for exchanging heat between the carbon dioxide passing through the injection pump and the carbon dioxide passing through the compressor, considerable energy can be saved in liquefying and storing the carbon dioxide.

In addition, the heat exchanger can be placed between the injection pump and the heater so that it can be heated through the heat exchanger and then heated by the heater, thereby reducing considerable energy in storing the carbon dioxide.

1 is a system diagram of a carbon dioxide liquefaction and underground injection apparatus according to an embodiment of the present invention.
2 is a Ph diagram of the carbon dioxide liquefaction and underground injection apparatus of FIG.
3 is a view showing the carbon dioxide flow in the gas-liquid separator of the carbon dioxide liquefaction and underground injection apparatus of FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a carbon dioxide liquefaction and underground injection apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. This is for the purpose of illustrating the present invention and is not intended to limit the scope of protection defined by the appended claims.

1 is a ph diagram of a carbon dioxide liquefaction and underground injection apparatus of FIG. 1, FIG. 3 is a ph diagram of a carbon dioxide liquefaction and underground injection apparatus according to an embodiment of the present invention, Liquid separator of the injection apparatus.

1, a carbon dioxide liquefaction and underground injection apparatus 100 according to an embodiment of the present invention includes a supply unit 110, a compressor 120, a cooler 130, an expansion valve 140, and a gas-liquid separator 150 A pressurization pump 160, an injection pump 170, a heater 180, and a heat exchanger 190.

The supply unit 110 is a device for supplying carbon dioxide collected at a power plant or the like to the compressor 120.

Techniques for collecting carbon dioxide from a carbon dioxide emission source such as a steel mill or a thermal power plant include post-combustion recovery technology, pre-combustion recovery technology, and pure oxygen combustion technology, but this embodiment is intended to reduce carbon dioxide emitted to the atmosphere, There is no.

The compressor (120) is a device for compressing gaseous carbon dioxide supplied from a supply part (110) into gaseous carbon dioxide at high temperature and high pressure.

At this time, if the carbon dioxide can be compressed to a high temperature and a high pressure in order to liquefy the carbon dioxide, the kind of the compressor 120 is not a problem.

The cooler 130 is a device for cooling carbon dioxide in a high-temperature and high-pressure state, which has passed through the compressor 120, into carbon dioxide in a low-temperature and high-pressure state.

Generally, liquid carbon dioxide can be obtained by compressing carbon dioxide to high pressure and then cooling it.

In this embodiment, chiller is used for cooling the carbon dioxide. However, if the liquid carbon dioxide can be obtained by cooling the high-temperature and high-pressure carbon dioxide, the type of the cooler 130 is not limited.

The gas-liquid separator 150 is a device for separating gaseous carbon dioxide and liquid carbon dioxide that coexist while passing through the expansion valve 140.

Carbon dioxide is a gas at room temperature and normal pressure, so even if it is transported by pipeline, the necessary infrastructure is very expensive. Therefore, it is preferable to transport liquefied carbon dioxide.

When the carbon dioxide that has passed through the cooler 130 passes through the expansion valve 140, the pressure is lowered. At this time, the gaseous carbon dioxide and the liquid carbon dioxide coexist.

3, the liquid carbon dioxide that has passed through the gas-liquid separator 150 is changed into a supercritical state and supplied to a pressurizing pump 160, which will be described later, to be injected into the ground.

Further, the gaseous carbon dioxide passing through the gas-liquid separator 150 is supplied to the compressor 120 so as to be converted into liquid carbon dioxide again.

That is, as the carbon dioxide passing through the cooler 130 passes through the expansion valve 140, the pressure is lowered. At this time, gaseous carbon dioxide and liquid carbon dioxide are present, and the gas- After separation into liquid carbon dioxide, the gaseous carbon dioxide is supplied to the compressor 120 for liquefaction, and the liquid carbon dioxide is supplied to the pressurization pump 160 for injection into the ground.

The pressurizing pump 160 supplies the liquefied carbon dioxide to the infusion pump, which will be described later. The infusion pump 170 pressurizes the carbon dioxide to a high pressure so that cavitation does not occur.

Here, cavitation refers to a phenomenon in which a cavity is formed in a fluid due to a pressure change due to a velocity change of the fluid, which is also referred to as a cavitation phenomenon.

According to Bernoulli's theorem, as the flow velocity increases, the pressure becomes smaller, and conversely as the flow velocity becomes smaller, the pressure increases.

When a propeller such as an impeller, which is one of the components of the infusion pump 170 described later, rotates at high speed, the fluid velocity around the propeller also increases.

That is, as the velocity of the fluid increases, the pressure is reduced by Bernoulli's theorem.

At this time, when the pressure of the fluid gradually decreases and becomes lower than the saturation pressure, the liquid carbon dioxide is changed into the gaseous carbon dioxide.

The air bubbles generated by the carbon dioxide in the gas phase are called cavities. The air bubbles are discharged under pressure, and are destroyed, and shock waves are generated.

Since the collapse and disappearance of cavities occurs instantaneously, the volume is suddenly reduced in the process of changing from bubbles to liquid water, and a strong impact force is applied.

The impact of the pump increases the noise and vibration of the pump, which causes damage to the internal components of the pump 170, shortening the service life of the pump 170, failure, and reducing the efficiency of the pump 170.

That is, the pressurizing pump 160 prevents the cavitation from occurring by increasing the pressure of the liquid carbon dioxide by a certain pressure even if the propeller of the injection pump 170 rotates at a high speed to decrease the pressure.

The injection pump 170 is a device that pressurizes the liquid carbon dioxide supplied from the pressurization pump 160 into a supercritical state and stores it in the ground.

For efficient storage of carbon dioxide, the density of carbon dioxide must be high and the viscosity should be low.

This condition is formed at a high temperature and a high pressure state in which carbon dioxide changes into a supercritical state.

At a temperature of 31.1 ° C and a pressure of 7.38 MPa, carbon dioxide forms a critical point at which the liquid and the gas can coexist, and exists as a supercritical state at a condition above the critical point.

At this point, the diffusivity of the gas and the solubility of the liquid are shown together, which makes it possible to inject and store carbon dioxide.

Underground storage is intended for deep strata below 800m under which these conditions can be met.

That is, the injection pump 170 is a device that pressurizes the liquid carbon dioxide supplied from the pressurization pump 160 to a high pressure in order to change it into a supercritical state.

The injection pump 170 includes an impeller for rotating and pressurizing carbon dioxide, an inlet for supplying liquid carbon dioxide from the pressurization pump 160, and a discharge unit for supplying high-pressure carbon dioxide to a heater, which will be described later.

There is a problem that the impeller rotates at a high speed and pressurizes the carbon dioxide to a high pressure and the impeller rotates at a high speed to reduce the pressure and cavitation in the process of increasing the pressure again. The problem can be solved.

On the other hand, if the injection pump can pressurize the liquid carbon dioxide to a high pressure, the type and configuration of the pump are not limited.

The heater 180 is a device for heating the high-pressure carbon dioxide supplied from the injection pump 170 into a supercritical state.

The type of the heater is not limited as long as it can be converted into supercritical carbon dioxide by heating the high-pressure carbon dioxide.

The heat exchanger 190 is a device for reducing energy by mutually exchanging the carbon dioxide in the cooling line for liquefaction and the carbon dioxide in the heating line for making the supercritical state.

The heat exchanger 190 is disposed on the carbon dioxide flow path between the inflow pump 170 and the heater 180 and conveys the carbon dioxide of high temperature and high pressure passing through the compressor 120 and the carbon dioxide of low temperature and high pressure, Energy is reduced by heat exchange.

The carbon dioxide that has passed through the compressor 120 must pass through the cooler 130 in order to make liquid carbon dioxide. The carbon dioxide passed through the injection pump 170 to make supercritical carbon dioxide for underground injection The heater 180 should be heated.

That is, the heat exchanger 130 exchanges heat between the high-temperature and high-pressure carbon dioxide that has passed through the compressor 120 and the low-temperature and high-pressure carbon dioxide that has passed through the injection pump 170 to exchange energy for cooling the high- Temperature high-pressure carbon dioxide that has passed through the compressor 120 and uses the energy of the high-temperature high-pressure carbon dioxide that has passed through the compressor 120 to heat the low-temperature high-pressure carbon dioxide.

Thereby, the energy of the cooler 130 used for cooling the carbon dioxide at high temperature and high pressure and the energy of the heater 180 used for heating the carbon dioxide at low temperature and high pressure can be considerably reduced.

On the other hand, if the high-temperature high-pressure carbon dioxide passed through the compressor 120 and the low-temperature high-pressure carbon dioxide passing through the injection pump 170 can mutually heat-exchange to reduce the energy, the type and configuration of the heat exchanger 190 are not limited .

Hereinafter, the operation of the carbon dioxide liquefaction and underground injection apparatus according to one embodiment of the present invention will be described.

First, the supply unit 110 supplies the carbon dioxide collected at a power plant or the like to the compressor 120.

The collected carbon dioxide is converted into carbon dioxide at high temperature and high pressure while passing through the compressor (120).

Thereafter, the carbon dioxide in the high-temperature and high-pressure state is cooled while passing through the cooler 130.

At this time, the cooling of the carbon dioxide can be cooled by first using the energy of the carbon dioxide which is liquefied and injected into the ground.

That is, the heat exchanger 190 exchanges heat with low-temperature and high-pressure carbon dioxide which has passed through the inflow pump 170 and is cooled at a predetermined temperature, and then cooled through the cooler 130, .

The carbon dioxide passing through the heat exchanger 190 and the cooler 130 is reduced in pressure while passing through the expansion valve and the liquid phase carbon dioxide and the gaseous carbon dioxide which are coexisting with each other are separated through the gas-liquid separator 150.

At this time, the gaseous carbon dioxide separated and passed through the gas-liquid separator 150 is supplied again to the compressor 120 so that it can be re-converted into liquid carbon dioxide.

On the other hand, the liquid ideal carbon dioxide separated and passed through the gas-liquid separator 150 is supplied to the pressurizing pump 160 to be injected into the ground.

As described above, the pressurizing pump 160 increases the pressure of the liquid carbon dioxide to a predetermined pressure so that cavitation does not occur.

That is, the liquid carbon dioxide is supplied to the injection pump 170 while being pressurized by the pressure pump 160.

The pressure of the carbon dioxide supplied to the injection pump 170 is instantaneously lowered due to the rotation of the impeller in the injection pump 170 at a high speed and then raised again so that cavitation may occur. So that it can be prevented.

The carbon dioxide that has passed through the injection pump 170 becomes carbon dioxide in a low temperature and high pressure state.

Then, the carbon dioxide that has passed through the injection pump 170 is heated while passing through the heater 180, and is changed into carbon dioxide in the supercritical state.

At this time, the heating of the carbon dioxide can be heated using the energy of the carbon dioxide in the high-temperature high-pressure state passed through the compressor 120.

That is, the heat is exchanged with the high-temperature and high-pressure carbon dioxide which has passed through the compressor 120 through the heat exchanger 190, heated by a predetermined temperature, and then heated through the heater 180, can do.

The scope of the present invention is not limited to the above-described embodiments, but may be embodied in various forms of embodiments within the scope of the appended claims. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as claimed in the appended claims.

100: CO2 liquefaction and underground storage device 110:
120: compressor 130: cooler
140: expansion valve 150: gas-liquid separator
160: Pressurizing pump 170: Infusion pump
180: heater 190: heat exchanger

Claims (5)

A supply unit for supplying carbon dioxide;
A compressor for compressing the carbon dioxide supplied from the supply unit to a high pressure and a high temperature;
A cooler for cooling the carbon dioxide that has passed through the compressor;
A gas-liquid separator for separating the carbon dioxide passed through the cooler into carbon dioxide in gas phase and carbon dioxide in liquid phase;
Liquid separator for converting the liquid carbon dioxide passed through the gas-liquid separator into a supercritical state and injecting the liquid carbon dioxide passed through the gas-liquid separator into the ground, And an injector including a heater for heating the carbon dioxide to a supercritical state,
Liquid separator, and the gas-phase carbon dioxide having passed through the gas-liquid separator is re-supplied to the compressor for recompression. The method according to claim 1,
Wherein the injection unit further comprises a pressurizing pump for increasing the pressure of the liquid carbon dioxide to a predetermined pressure and supplying the carbon dioxide to the injection pump so that cavitation does not occur. 3. The method according to claim 1 or 2,
Further comprising a heat exchanger for exchanging heat between the carbon dioxide passing through the injection pump and the carbon dioxide passing through the compressor. The method of claim 3,
Wherein the heat exchanger is located on a carbon dioxide flow path between the injection pump and the heater. delete

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