Method for reducing exhaust carbon dioxide

Abstract

A method for effectively absorbing and removing CO2 in an exhaust gas generated during an industrial process for reducing the amount of CO2 that is exhausted into the atmosphere. The exhaust gas containing CO2 is blown into an agglomerate of solid particles containing CaO and / or Ca(OH)2 so that the CO2 is in contact with the agglomerate for fixing the CO2 in the exhaust gas as CaCO3, thereby reducing the CO2 concentration in the exhaust gas. Preferably, the solid particles contain water, and more preferably, the solid particles contain surface adhesive water.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] This application is a divisional application of application Ser. No. 09 / 844,533 filed on Apr. 27, 2001, which is a continuation application of International application No. PCT / JP99 / 05972(not published in English), filed on 28 Oct. 1999, the entire contents of which are incorporated by reference herein.FIELD OF THE INVENTION [0002] The present invention relates to a method for reducing CO2 concentration in exhaust gas generated in an industrial process and others, and reducing the amount of exhausting CO2 in an atmospheric air. Further, the present invention relates to a water immersion block for seaweed and algae planting places, fish gathering rocky places or riverbeds, and a method for making the same. Herein, the above mentioned “seaweed and algae planting places” designate groups or communities of marine algae (algae, seaweed and the like) growing in the sea bottom. BACKGROUND OF THE INVENTION [0003] Recently, from the viewpoint of...

AI Technical Summary

Benefits of technology

[0030] It is a first object of the invention to provide a method that effectively absorbs and removes CO2 in an exhaust gas generated in an industrial process for reducing an amount of exhausting CO2 into the atmospheric air.

[0031] The inventors made detailed investigations on materials of absorbing CO2 and a method of using the same in order to find a method which effectively absorbs and removes CO2 in the exhaust gas on an industrial scale. As a result, they found that as the CO2 absorbing material, optimum was an agglomerate of solid particles containing CaO such as slag or concrete. The inventors also found that by blowing exhaust gas containing CO2 in an agglomerate of the solid particles to be in contact with the exhaust gas, and especially preferably by blowing the exhaust gas, under the condition that the gas dissolves into the suitable amount of water content and the successive reaction (more preferably, surface adhesive water of the solid particles) to contact with the exhaust gas, it was possible to fix CO2 in the exhaust gas as CaCO3 in the solid particles and effectively absorb and remove CO2.

[0051] It is a second object of the present invention to provide a water immersion block. The immersion block is excellent for rearing algae and breeding fish and shellfish without heightening the pH in seawater or river water. The present invention also provides a method of making the same, and a further method of building an algae planting place using a water immersion block.

[0060] causing a carbonation reaction in the mixture in a packed bed by using carbon dioxide so as to make the mixture massive.

Problems solved by technology

However, in the present high degree industrialized society, there is per se a limit in the control of using energy which is related to the cutting of the exhaust of CO2, and it is not always easy to accomplish a target of cutting CO2 exhaust only with the control of the amount of energy used.

However, an effective method which removes CO2 from the exhaust gas on an industrial scale is not yet conventionally known.

However these methods are involved with problems as discussed herein.

However, as a block for the algae planting places, the massive slag has functions (adhering property of sea algae or rearing property) only of a similar degree to a natural block, and does not have a special function of accelerating the growing of sea algae.

Slag for algae planting places necessitates sizes of a certain degree, and slag broken for recovering the metal is scarcely used.

If use is made of the massive slag as a block for algae planting places, the recovery of the metal useful as iron and steel sources can hardly be practiced.

In contrast, if massive slag containing much metal is immersed into the sea as it is for use as a block in algae planting places, the iron content in the slag is oxidized, depending on sea areas, to cause a shortage of oxygen in the seawater, and further by dissolution of the iron content; the iron content might be excessively supplied in the sea water.

Such finely pulverized slag cannot be used as materials to be immersed in the sea water for the algae planting places.

On the other hand, the latter method uses slag as an agglomerate of a concrete made pre-cast body, and so there seldom occurs a problem of the case that the massive slag is immersed in the sea as it is.

However materials available by this method are concrete products whose surfaces are composed of cement mortar, and which therefore cannot exhibit even the properties of massive slag (for example, uneven surface property) which are expected to display performance per se as for algae planting places.

For repairing riverbeds, enormous amount of blocks are required.

It probably causes destruction of nature to supply natural blocks from other places, and since natural blocks are not cheap, the construction cost is increased.

However these methods have problems as discussed hereinabove.

Since the slag generated in the iron and steel making process contains much metal (grain iron), if massive slag is immersed in the water as it is, grain iron is oxidized, and depending on water ranges, a shortage in oxygen might occur in neighboring rivers.

Such finely pulverized slag cannot be used as materials to be immersed in the sea water for algae planting places.

On the other hand, as in the latter method, if the slag is used as an agglomerate of a concrete made pre-cast body, since the base is made of concrete, the properties of the massive slag (for example, uneven surface property) which are expected to display performance as an immersion block in the rivers cannot be displayed.

However, since the concrete-made fish way has a smooth bottom, it is difficult for water living creatures such as algae to live, and there are problems for water living plants (for example, crusts or water living insects) relating to moving because of the catching with their claws on the riverbed (surface projections as a block for water living plants).

For these problems, there is a method of structuring the fish way with a foam concrete to make fine indentations on the bottom of the fish way, however the construction cost is high with less practicability.

In either way, the concrete has a high pH, which is not preferable for water living creatures moving on the riverbed.

However, nowadays, the algae planting places continue to rapidly fade or decline by influences of reclaiming coasts or corruption of the seawater.

In particular, recently, in many coastal or sea areas, a big problem of so-called “shore burn” phenomena occurs.

Of these methods, the method (1) is advantageous in wide selecting ranges for creating the algae places, however, basically all of the creations are artificial, and it is necessary to fully manage taking-roots or rearing of transplanted seeds and saplings, for which a lot of time and tremendous cost are taken.

This method is absolutely unsuited to large scale creations of algae places.

However, this method is short with respect of general purpose uses because of limited places to become algae places.

Accordingly, it is assumed that this method is difficult to create algae places at places where circumferentially whole algae places have been faded by shore burn.

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