JPH04104834A - Treatment of co2 into the ocean - Google Patents

Abstract

PURPOSE:To prevent liquid CO2 from floating up and diffusing into the air by pouring liquid CO2 into the ocean with required depth in such a manner that it is dispersed not so as to concentrate on one place. CONSTITUTION:Liquid CO2 is poured into the ocean with required depth in such a manner that it is dispersed not so as to concentrate on one place. For example, liquid CO2 stored in a storage tank 5 is suitably loaded into a transportation ship 9, is transported to an ocean tank 7 and is poured into the ocean with about >400m water depth from the ocean tank 7 via a pouring pipe 8. At this time, the pouring pipe 8 is rotated and disperses liquid CO2 blown from the tip part bent approximately into an L-shape in the pouring pipe 8 into the ocean without concentrating it on one place, by which the heat of solution and the heat of hydration generated in the case liquid CO2 and water are brought into reaction with to form a hydrate are dispersed. As a result, the rise of the temp. of sea water in the pouring part of liquid CO2 and that of liquid CO2 are made small, and the increase in its buoyancy can be reduced, by which the floating-up of liquid CO2 and its diffusion into the air can be prevented and the treatment of CO2 into the ocean can surely be executed.

Description

[Detailed description of the invention] [Industrial application fields] The present invention relates to a CO2 ocean treatment method.

[Prior Art] In recent years, as a measure to prevent global warming, separation of Coy from fossil fuel combustion exhaust gas has been considered.

The CO2 emitted from boilers is much larger than SOx and NOx, and a 600MW pulverized coal-fired boiler emits about 3 million tons of CO2 annually. Even assuming that 20% of CO2 was separated from this boiler exhaust gas, the amount would be 600,000 tons, which would exceed the 520,000 tons of carbon dioxide sold domestically in 1984.

Because such a large amount of CO2 is emitted, the ocean is being considered as the best place to dispose of it.

Figure 4 is a conceptual diagram of the marine CO2 treatment currently being considered. 1 is a boiler in a thermal power plant, 2 is a removal device such as an absorption tower filled with monoethanolamine or the like as an absorbent, and 3 is a chimney. , 4 represents a CO2 liquefaction unit that liquefies CO2 by compressing and cooling it, 5 represents a CO2 storage tank that stores liquid CO2, and 6 represents a vibrator extending from the CO2 storage tank 5 to the seabed.

The exhaust gas from the boiler 1 has SOx, NOx, etc. separated and removed by a device (not shown), and then CO2 is separated and removed by a CO2 removal device 2, and then released into the atmosphere from a chimney 3.

C separated from the exhaust gas by the CO2 removal device 2
The O2 gas is sent to the CO2 liquefaction device 4, where it is liquefied and then stored in the CO2 storage tank 5 as liquid CO7.

The liquid CO2 stored in the CO2 storage tank 5 is injected into the sea via a pipeline 6.

[Problem to be solved by the invention] When liquid CO2 is injected into the sea via the pipeline 6 as described above, due to the relationship between sea depth (pressure) and seawater temperature, it is difficult to inject liquid CO2 into a place shallower than about 400 m deep. If CO2 is injected, the liquid CO2 will vaporize and rise rapidly, dissipating from the sea surface into the atmosphere, so it is necessary to inject the liquid CO2 to a depth of at least about 400 meters (
However, if the seawater temperature is high, it may be necessary to inject deeper.)

Now, when the liquid CO2 is injected into the sea at a depth of approximately 400 to 3000 meters, a portion of the injected liquid CO2 reacts with water and forms a hydrate (chemical formula CO27H20 or CO2.6H).
Other liquid CO2 is absorbed by seawater and slowly floats up to the surface, reaching a depth shallower than approximately 400 meters without being completely absorbed by seawater. This poses a problem because the liquid CO2 vaporizes, rises rapidly, and dissipates from the sea surface into the atmosphere.

On the other hand, at depths deeper than about 3,000 m, liquid CO2 will not float if the temperature of liquid CO2 is the same as or lower than the seawater temperature, due to the relationship between the specific gravity of seawater and liquid CO2. This means that it is only necessary to inject deeper than 3000m.

However, when some of the liquid CO2 injected into the sea reacts with water to produce hydrates, heat of dissolution and heat of hydration are generated. When a large amount of liquid CO2 is intensively injected into one place, a large amount of heat of dissolution and hydration is generated, and this heat causes the specific gravity of the liquid CO2 at the injection site to become smaller than the specific gravity of seawater or the surrounding seawater. Smaller, depth 400-3000
If it is injected into one area of rn, the floating of liquid CO. will be accelerated, and it will be necessary to inject deeper. or,
Even if liquid CO2 is injected into water deeper than approximately 3,000 rn, there is a possibility that the liquid CO2 will float to the surface for the same reason.

In view of the above circumstances, the present invention aims to provide an underwater CO2 processing method that can prevent liquid CO2 from rising up to 1W and dissipating into the atmosphere.

[Means for Solving the Problems] The present invention is characterized in that liquid CO2 is dispersed and injected into the sea at a required depth so as not to be concentrated in one place.

[Function] Therefore, when liquid CO2 is injected into the sea at the required depth in a dispersed manner so as not to concentrate in one place, the heat of dissolution generated when liquid CO2 reacts with water and a water phase is produced. , the heat of hydration is also dispersed, and as a result, the rise in seawater and liquid CO2 at the liquid CO2 injection site is small, making it possible to reduce the increase in buoyancy; injection becomes possible.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, in which parts with the same symbols as in FIG. 4 represent the same parts, and liquid CO2
The process up to storing CO2 in the CO2 storage tank 5 is the same as that shown in FIG.

In the case of this embodiment, a marine tank 7 is provided on a rig installed in a sea area deeper than about 400 m deep, and an injection pipe 8 extending from the offshore tank 7 into the sea deeper than about 400 m deep is provided. The tip of the tube 8 is bent into an abbreviated shape, and the injection tube 8 is rotatable, so that the liquid CO2 stored in the CO2 storage tank 5 can be transported to the marine tank 7 by a transport ship 9. .

Next, the operation of the above embodiment will be explained.

The liquid CO2 stored in the CO2 storage tank 5 is appropriately loaded onto a transport ship 9, transported to a marine tank 7, and is injected from the marine tank 7 into the sea at a depth of about 400 m or more via an injection pipe 8.

At this time, the injection tube 8 is rotating, and the liquid CO2 blown out into the sea from the bent tip of the injection tube 8 is not concentrated at the - point but is dispersed.
The heat of solution and water utilization generated when 2 reacts with water to form a hydrate are also dispersed.

As a result, seawater and liquid C at the injection part of liquid CO2
It is possible to reduce the rise in O2, reduce the increase in buoyancy, prevent liquid CO2 from floating and dissipating into the atmosphere, and ensure that CO2 is disposed of into the ocean.
It can be used to help prevent global warming.

In the above embodiments, the injection tube 8 is made rotatable, or the injection tube 8 is configured to be freely movable in the vertical direction within the required depth range, or is configured to be freely movable in the horizontal direction. Good too.

2 and 3 respectively show modified examples of the shape of the tip of the injection tube 8. In the example shown in FIG. 2, a plurality of branch tubes 10 are branched from the injection tube 8. A large number of blow-off nozzles 11 are provided protrudingly, and in the case of the one shown in FIG. 3, a plurality of branch pipes 10'' are further branched from a plurality of branch pipes 10 branching from the injection pipe 8, and a large number of blow-off nozzles are provided in the branch pipe 10'. A nozzle 11 is provided in a protruding manner.

If the shape of the tip of the injection tube 8 is changed as shown in Figure 2.3, the liquid CO2 blown out into the sea will be dispersed more actively, and the heat load per unit volume at the liquid CO2 injection part will be reduced. or become smaller.

Therefore, as mentioned above, it is possible to rotate the injection tube 8 or reduce the speed at which it is moved vertically or horizontally, and in places with fast ocean currents, liquid CO2 can float to the surface without moving the injection tube 8. It can prevent dissipation into the atmosphere.

Furthermore, the throughput of the blowout nozzle 11 is significantly reduced when liquid CO2 is blown out all at once from the tip of the injection tube 8 as shown in Fig. 1, and the droplets of liquid CO7 are made finer. As a result, CO2 absorption into seawater is improved, and from this point of view, CO2 dissipation into the atmosphere is reduced by μ41.
You will be able to stop it.

It should be noted that the CO2 marine treatment method of the present invention is not limited to the above-described embodiments, and it goes without saying that various changes may be made without departing from the gist of the present invention.

[Effects of the Invention] As explained above, according to the CO2 marine treatment method of the present invention, CO2 discharged from a boiler etc. is liquefied and dispersed into the sea before being injected. Since the rise in seawater and liquid CO2 is small, the increase in buoyancy is small, and even when injected into a shallower area than when injected directly, liquid CO2 can be prevented from floating to the surface and dissipating into the public. It becomes possible to reliably dispose of CO2 in the ocean, which has the great effect of helping to prevent global warming.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram showing one embodiment of the present invention, Figs. 2 and 3 are perspective views showing modifications of the tip shape of the injection tube shown in Fig. 1, and Fig. 4 is a currently considered example. It is a conceptual diagram of ocean processing of CO2. 7 is a marine tank, 8 is an injection pipe, 9 is a transport ship, 10.10
11 indicates a branch pipe, and 11 indicates a blowing nozzle.

Claims (1)

[Claims] 1) A CO_2 marine treatment method characterized by injecting liquid CO_2 into the sea at a required depth in a dispersed manner so as not to concentrate in one place.