KR100712585B1 - Method and apparatus for separating and recovering carbon dioxide - Google Patents

Abstract

A method of separating and recovering carbon dioxide from a by-product gas generated in a steel mill by a chemical absorption method, and absorbing carbon dioxide from the gas into the chemical absorbent liquid, and then heating the chemical absorbent liquid to separate carbon dioxide. It is characterized by using or utilizing.

CO2, By-Product Gas, Absorption Tower, Transmission Pipe, Regeneration Heat Source

Description

Method and apparatus for separating and recovering carbon dioxide {METHOD AND APPARATUS FOR SEPARATING AND RECOVERING CARBON DIOXIDE}

The present invention relates to a method and apparatus for separating and recovering carbon dioxide (hereinafter, simply abbreviated as CO ₂ ). In detail, when the CO ₂ is separated and recovered using the chemical absorption method, the absorption medium which has completed the absorption of CO ₂ from the CO ₂ containing gas supplied from a plurality of CO ₂ (generating) sources is integrated and regenerated at one site. The present invention relates to a method and apparatus for separating and recovering CO ₂ that makes it possible to increase the efficiency or to use an arrangement located at a different location from the CO ₂ (generating) source.

Alternatively, in a steel mill having a large CO ₂ generation source, CO, such as by-product gas (unburned gas), its combustion exhaust gas, or its reforming process gas, which utilizes or utilizes a low-grade (low temperature) array that is difficult to use even when heat recovery as an array. _It relates to a method for separating and recovering CO ₂ from _2- containing gas.

In recent years, measures against global warming have been focused on the promotion of energy saving in the manufacturing and use stages, the utilization of new energy such as solar light, wind power, and biomass, and the transition to low environmental load fuels such as natural gas. It is strongly promoted.

On the other hand, researches to separate and recover the generated global warming gas (carbon dioxide) have been carried out. For example, a method of recovering, using the chemical absorption process from a combustion waste gas of thermal power plant to remove the carbon dioxide has been proposed (for example, a bulletin let Masai takka, "CO ₂ recovery test from the power generation boiler exhaust gas", Energy and Resources, Energy and Resources Society, 1993, Vol. 14, No. 1, pp.91-97). According to this proposal, 90% of the separated recovery rate of carbon dioxide can be achieved depending on the conditions.

However, when carbon dioxide is separated and recovered from the combustion exhaust gas of the thermal power plant (boiler exhaust gas for power generation) by chemical absorption method, the carbon dioxide concentration contained in the combustion exhaust gas of the thermal power plant is low, ranging from several to tens of volume percent, The equipment used for the chemical absorption method was supposed to be large scale. In addition, when separating and recovering carbon dioxide by a chemical absorption method, thermal energy is a dominant factor in operating costs.

However, in a thermal power plant optimized for a single process called power generation, there are no arrangements available for chemical absorption methods, and there must be a way to reduce power generation efficiency by installing new thermal energy generation facilities or by utilizing steam used for power generation. Only did.

On the other hand, there is no economic advantage in segregating recovered carbon dioxide in the ground or in the ocean (simple cost increase), and the domestic market is small and usually meets demand even if it is effectively utilized as chemical raw materials. There are structural problems, such as no traction.

Therefore, it is an object of the present invention to provide a technique for efficiently and inexpensively separating and recovering carbon dioxide emitted from an ironworks, one of the large-scale carbon dioxide generators, in a small-scale facility compared to a thermal power plant.

In addition, another object of the present invention is to provide a technique for separating and recovering carbon dioxide from a carbon dioxide generating source efficiently and inexpensively by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location.

Therefore, the present inventors have earnestly examined a technique for separating and recovering carbon dioxide discharged from a large-scale carbon dioxide generator in order to achieve the above object, and as a result, by-product gas such as blast furnace gas generated from a steel mill that is a large-scale carbon dioxide generator (unburned gas) It was found that the ratio (concentration) of carbon dioxide was as high as 20 to 30% by number, unlike the combustion exhaust gas in which the fossil fuel was air-fired.

As a result, in the case of separating and recovering carbon dioxide by using a chemical absorption method, it was realized that a facility for separating and recovering the same amount of carbon dioxide compared to a thermal power plant can be miniaturized.

In addition, steel mills consist of numerous processes such as blast furnaces, converters, sintering, coke furnaces, heating furnaces, castings, and rolling mills, and various improvements have already been made to save energy. It was thought that it was not left.

However, it has also been realized that the use of this energy for heating or heating the chemical absorption liquid, which is the dominant factor in operating costs, can significantly reduce the operating costs of the chemical absorption method.

In addition, although the by-product gas is used as a fuel gas in the steelmaking process, it has been realized that by extracting carbon dioxide in the middle, the energy density of the gas can be increased to improve the thermal efficiency of the process at the rear end.

Further, the combustion exhaust gas after the by-product gas in the converter gas, by combustion in the steel mill, because it contains CO ₂ at a high rate on the 30 number%, I found that we can further reduce the size of the equipment for separating and recovering carbon dioxide .

Based on these findings, the present invention has been completed.

In addition, when the inventors analyze the cost of carbon dioxide separation recovery by chemical absorption method, the biggest cost factor is the regenerative heat source of the carbon dioxide absorption medium, and the purpose of this efficiency is to separate and recover carbon dioxide efficiently and inexpensively. The conclusion was valid in achieving.

That is, the present invention can be achieved by a method for recovering and separating carbon dioxide described in (1) to (22) below.

(1) a method of separating and recovering carbon dioxide from a by-product gas generated in a steel mill by a chemical absorption method,

And absorbing carbon dioxide from the gas into the chemical absorption liquid, and then heating or using the chemical absorption liquid to separate the carbon dioxide, using or utilizing a low-grade array of 500 ° C. or less generated in a steel mill.

(2) a method of separating and recovering carbon dioxide from a combustion exhaust gas of by-product gas generated in a steel mill by a chemical absorption method,

And absorbing carbon dioxide from the gas into the chemical absorption liquid, and then heating or using the chemical absorption liquid to separate the carbon dioxide, using or utilizing a low-grade array of 500 ° C. or less generated in a steel mill.

(3) a method of separating and recovering carbon dioxide from a process gas produced in a reforming process for producing hydrogen from a by-product gas generated in a steel mill by a chemical absorption method,

After absorbing carbon dioxide from the gas into the chemical absorbing liquid, the method for separating and recovering carbon dioxide by heating the chemical absorbing liquid using or utilizing a low-grade array of 500 ℃ or less generated in the steel mill.

(4) The carbon dioxide concentration in the by-product gas, combustion exhaust gas, and process gas provided to the chemical absorption method is 15 vol% or more, and the separated and recovered carbon dioxide according to any one of (1) to (3) above. Way.

(5) The separation and recovery method of carbon dioxide according to any one of (1) to (4), wherein the byproduct gas is at least one kind of blast furnace gas, coke oven gas, and converter gas.

(6) The separation and recovery method of carbon dioxide according to any one of (1) to (5), wherein an arrangement generated in a steel mill is used as the total amount or part of the heat amount required for regeneration of the chemical absorption liquid.

(7) The method for separating and recovering carbon dioxide according to any one of the above (1) to (6), wherein the appropriate arrangement generated in the steel mill is used for regeneration of the chemical absorption liquid in accordance with the characteristics of the chemical absorption liquid. .

(8) In order to regenerate the chemical absorption liquid, the carbon dioxide produced in any one of the above (1) to (7), which uses or utilizes an arrangement generated in a steel mill as much as possible, and uses steam for the factory. Separation Recovery Method.

(9) an apparatus for separating and recovering carbon dioxide from a carbon dioxide generating source,

A carbon dioxide absorption facility for absorbing carbon dioxide into a carbon dioxide absorption medium from a carbon dioxide containing gas supplied from a carbon dioxide generating source,

An absorption medium regeneration facility for regenerating the absorption medium by separating carbon dioxide from the absorption medium absorbing carbon dioxide using a heat source for regenerating the absorption medium;

A carbon dioxide absorption medium circulating between the two facilities as a transportation medium of carbon dioxide,

It is provided with a delivery pipe and a return pipe for transporting a carbon dioxide absorption medium,

And the carbon dioxide absorption facility is provided in close proximity to the carbon dioxide generating source, and the absorption medium regeneration facility is installed at a different place from the carbon dioxide generating source.

(10) The distance (A) between the carbon dioxide generating source and the carbon dioxide absorbing facility and the distance (B) between the absorbing medium regeneration facility and the heat source for regenerating the absorption medium, and the distance (C) between the carbon dioxide absorbing facility and the absorption medium regeneration facility, , A <C and B <C satisfy the relational formula, characterized in that the separation and recovery of carbon dioxide according to (9).

(11) a piping distance (X) for supplying carbon dioxide-containing gas from the carbon dioxide generating source to the carbon dioxide absorbing facility, a delivery piping distance (Y) and a return piping distance (Z) of the carbon dioxide absorbing medium, and a heat source for regenerating the absorption medium; The piping distance (W) for supplying heat to the absorption medium regeneration equipment from the satisfies at least one of 2X <(Y + Z) and (X + W) <(Y + Z). Separation and recovery apparatus of carbon dioxide as described in said (9) or (10) characterized by the above-mentioned.

(12) The separation and recovery apparatus for carbon dioxide according to any one of (9) to (12), wherein the absorption medium regeneration facility is provided in proximity to a process arrangement source used for the heat source for absorption medium regeneration.

(13) A separation and recovery apparatus for carbon dioxide according to any one of (9) to (12), wherein a process arrangement is used as part or all of the heat source for regeneration of the absorbent liquid.

(14) The separation and recovery apparatus for carbon dioxide according to any one of (9) to (13), comprising one or a plurality of carbon dioxide absorption facilities and one or a plurality of absorption liquid regeneration facilities.

(15) The separation and recovery apparatus for carbon dioxide according to any one of (9) to (14), wherein a part of or all of the heat source for regeneration of the absorbent liquid is used in a multistage process arrangement.

(16) a method for separating and recovering carbon dioxide from a carbon dioxide source,

A carbon dioxide absorption facility close to a carbon dioxide generating source, and after absorbing carbon dioxide from a carbon dioxide-containing gas supplied from the carbon dioxide generating source using a carbon dioxide absorption medium,

The carbon dioxide absorption medium is heated using a heat source for regeneration of absorbent liquid, and the carbon dioxide is separated and recovered by an absorption liquid regeneration facility at a different location from the carbon dioxide generating source.

(17) The distance (A) between the carbon dioxide generating source and the carbon dioxide absorbing facility and the distance (B) between the absorbing medium regeneration facility and the heat source for regenerating the absorption medium, and the distance (C) between the carbon dioxide absorption facility and the absorption medium regeneration facility , A <C and B <C satisfy the relational formula, characterized in that the separation and recovery method of carbon dioxide according to (16).

(18) a piping distance (X) for supplying a carbon dioxide-containing gas from the carbon dioxide generating source to the carbon dioxide absorbing facility, a delivery piping distance (Y) and a return piping distance (Z) of the carbon dioxide absorbing medium, and a heat source for absorbing medium regeneration. The piping distance (W) for supplying heat to the absorption medium regeneration equipment from the satisfies at least one of 2X <(Y + Z) and (X + W) <(Y + Z). Separation and recovery method of carbon dioxide as described in said (16) or (17) characterized by the above-mentioned.

(19) The method for separating and recovering carbon dioxide according to any one of (16) to (18), wherein the absorbent medium regeneration equipment is provided in proximity to a process heat source used for the heat source for regenerating the absorbent medium.

(20) The method for separating and recovering carbon dioxide according to any one of (16) to (19), wherein a process arrangement is used as part or all of the heat source for regeneration of the absorbent liquid.

(21) The method for separating and recovering carbon dioxide according to any one of (16) to (20), wherein the one or a plurality of carbon dioxide absorption facilities and one or a plurality of absorption liquid regeneration facilities are used.

(22) The method for separating and recovering carbon dioxide according to any one of (16) to (21), wherein a part of or all of the heat source for regeneration of the absorbent liquid is used in a multi-stage process arrangement.

1 is a view showing a process principle for separating and recovering carbon dioxide from a raw material gas containing carbon dioxide by chemical absorption method.

FIG. 2 is a diagram schematically showing a process for separating and recovering carbon dioxide from a source gas generated in a steel mill by a chemical absorption method, using an arrangement generated in a steel mill as the total amount of heat required for regeneration of the chemical absorption liquid.

FIG. 3 schematically shows a process for separating and recovering carbon dioxide from a source gas generated in a steel mill by chemical absorption method by utilizing a suitable arrangement generated in a steel mill for regeneration of the chemical absorbent liquid according to the characteristics of the chemical absorbent liquid. One drawing.

4 is a diagram schematically illustrating a process for separating and recovering carbon dioxide by chemical absorption method from raw material gas generated in a steel mill utilizing steam produced at a steel mill while utilizing an arrangement generated in a steel mill for regeneration of a chemical absorbent liquid. to be.

FIG. 5 is a diagram schematically showing a representative device of a second embodiment of the present invention, showing a device (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location. .

FIG. 6 is a diagram schematically showing another representative device of the second embodiment of the present invention, showing a device (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location. to be.

FIG. 7 is a diagram schematically showing still another representative apparatus of the second embodiment of the present invention, showing an apparatus (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location. Drawing.

FIG. 8 is a diagram schematically showing still another representative apparatus of the second embodiment of the present invention, showing an apparatus (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location. Drawing.

FIG. 9 is a diagram schematically showing another representative device of the second embodiment of the present invention, showing a device (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location. to be.

Fig. 10 is a view schematically showing the apparatus used in the first embodiment of the second embodiment of the present invention, and an apparatus (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source in another place. It is a figure which shows.

FIG. 11 is a diagram schematically showing a device used in a second embodiment of the second embodiment of the present invention, wherein a device (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location. It is a figure which shows.

FIG. 12 is a diagram schematically showing a device used in a third embodiment of the second embodiment of the present invention, wherein a device (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location. Figure is a diagram.

FIG. 13 is a diagram schematically showing a device used in a fourth embodiment of the second embodiment of the present invention, wherein a device (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location. It is a figure which shows.

14 is a diagram schematically showing a device used in a fifth embodiment of the second embodiment of the present invention, wherein a device (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at another location. It is a figure which shows.

EMBODIMENT OF THE INVENTION Hereinafter, although this invention is demonstrated for each requirement by taking specific embodiment (an Example) as an example, it cannot be overemphasized that this invention should not be limited to these embodiment.

A first embodiment of the present invention is a method for separating and recovering carbon dioxide from a raw material gas generated in a steel mill by a chemical absorption method,

As the source gas, at least one kind of gas selected from a by-product gas generated in a steel mill, a combustion exhaust gas of the by-product gas, and a process gas generated from a reforming process for producing hydrogen from the by-product gas is used, and the source gas is used. After absorbing carbon dioxide from the chemical absorption liquid, the chemical absorption liquid is heated to separate the carbon dioxide, characterized by using or utilizing a low-grade arrangement of 500 ° C. or lower generated in the steel mill.

(Plant to which the separation collection method of the present embodiment is applicable)

The plant to which the separation and recovery method of the present embodiment is applicable may be an ironworks in which by-product gas is generated, for example, from a blast furnace, a converter, a coke oven, or the like, and a low-quality array of 500 ° C. or lower can be supplied. .

(Raw gas)

The raw material gas used for the separation collection | recovery method of this embodiment should just be a by-product gas (unburned gas) generate | occur | produced in a steel mill. Although it depends also on the structure of a steel mill, when a blast furnace integrated steel mill is taken as an example, blast furnace gas (BFG), coke oven gas (COG), converter gas (LDG) can be mentioned as a raw material gas, In addition, by-products, such as COG and LDG, are mentioned Also included are gases produced during the process (process) of reforming the gas for hydrogen production purposes (process gas).

These by-product gases may be used individually by 1 type, and may mix and use two or more types in a mixed state. In the separation and recovery method of the present embodiment, the combustion exhaust gas of the by-product gas may be used as the source gas for separation and recovery of carbon dioxide.

These raw material gases (by-product gas generated from a steel mill to the combustion exhaust gas) are used after the use when they are available as a high quality array. It is because the temperature at the time of carbon dioxide absorption by a chemical absorption method should just be a temperature near normal temperature.

Each of these source gases may be used alone or in combination to separate and recover carbon dioxide, or two or more thereof may be mixed and used to separate and recover carbon dioxide. The two or more types of mixed forms include not only mixed forms of by-product gases and mixed forms of combustion exhaust gases of by-product gases, but also mixed forms of combustion exhaust gases of by-product gases and by-product gases.

BFG has a high carbon dioxide ratio of 20% by weight in these source gases, and in addition, contains several% of hydrogen, which is a fuel component, and 20% of carbon monoxide. COG contains abundant hydrogen and methane which are suitable as fuel gas, and the carbon dioxide concentration in the exhaust gas after combustion (also referred to as combustion exhaust gas) is 20%.

On the other hand, LDG contains carbon monoxide at 70% and around with 10% carbon dioxide, and the carbon dioxide concentration of the exhaust gas (combustion exhaust gas) after combustion is very high at 30%.

Therefore, it is preferable to use BFG, the combustion exhaust gas of BFG, the combustion exhaust gas of COG, the combustion exhaust gas of LDG, and the mixed gas of these gases and other gas which have a carbon dioxide ratio higher than carbon dioxide of a thermal power plant as source gas.

Moreover, the gas produced | generated in the process of reforming COG and LDG mentioned later and producing hydrogen is also suitable.

Specifically, the carbon dioxide ratio (concentration) in the source gas generated from these steel mills is 15 volume% or more, preferably 18 volume% or more, more preferably 20 volume% or more, even more preferably 22 volume% or more, particularly Preferably it is 25 volume% or more.

When the carbon dioxide is separated and recovered from the gas having a high carbon dioxide ratio by means of a chemical absorption method or the like, combustion exhaust gas having a low carbon dioxide concentration in a thermal power plant (about 8% in a natural gas thermal power plant and about 12% in a coal thermal power plant) Compared to the case of using as a raw material gas, it is possible to significantly reduce the size of the equipment (for example, compared to the case of separating and recovering carbon dioxide from combustion exhaust gas having a low carbon dioxide concentration in a coal-fired power plant, When used for raw material gas, it is possible to reduce the equipment cost by about 30%).

(Separation Recovery Process of Carbon Dioxide)

In the separation recovery method of the present embodiment, carbon dioxide is separated and recovered from the source gas by a chemical absorption method. As a global warming countermeasure, when carbon dioxide is separated and recovered from a steel mill that is a large-scale carbon dioxide emission source, a large-scale facility capacity of 1 million t / year is required for separation recovery. In this case, the separation and recovery method of carbon dioxide, which is currently being developed and spread most, is a chemical absorption method, and the present invention also conforms to this chemical absorption method.

Hereinafter, the process principle of the chemical absorption method is shown using drawing. 1 is a view showing a process principle for separating and recovering carbon dioxide from a raw material gas containing carbon dioxide by chemical absorption method.

As shown in Fig. 1, the chemical absorption method uses a chemical absorption liquid, such as amines, in a reaction column called an absorption tower (1), which is a carbon dioxide absorption facility, and a chemical material that contains carbon dioxide and a carbon dioxide absorption medium. After absorbing the absorbent liquid 5 at about 50 ° C. and absorbing carbon dioxide into the chemical absorbent liquid, the liquid is passed through a pipe 6 to a regeneration tower 7 serving as an absorbent liquid regeneration facility, and is heated as a heat source for regenerating the absorbent liquid ( 9) was heated to around 120 ° C to recover carbon dioxide from the chemical absorbent liquid in the regeneration tower (7) and return the regenerated chemical absorbent liquid to the absorption tower (1) through the return pipe (8). It is a method of circulating between (1) and the regeneration tower 7.

A conventionally well-known thing, such as aqueous solution containing amines etc., can be used suitably for the said chemical absorption liquid, It does not specifically limit to a specific thing.

In the separation recovery method of the present embodiment, the thermal energy required for heating in the regeneration tower is the dominant factor of the operating cost in the separation recovery method. Therefore, in the separation and recovery method of the present embodiment, as a heat source for regenerating the absorbent liquid, a low-grade arrangement of 500 ° C. or lower, preferably 400 ° C. or lower, generated in the steel mill is used or utilized.

That is, in the separation and recovery method of the present embodiment, low-grade heat energy (preferably among the low-grade heat energy, which is preferably used or utilized as high as possible) is used or utilized in the steelmaking process, and therefore, thermal energy like a thermal power plant is used. It is not necessary to provide a generation facility to generate heating steam (heating medium 9) or to use steam used for power generation.

Therefore, the carbon dioxide separation recovery cost by the chemical absorption method can be greatly reduced. In addition, as described above, since the carbon dioxide concentration of the source gas is high, not only can the facility be compact, but also the amount of utility (electric power or water) required for the facility can be reduced, and the operating cost can be further reduced.

Here, the reason why the low quality arrangement generated in the steel mill used or utilized in the process of separating carbon dioxide is 500 ° C. or lower is due to the following reasons.

In other words, an array above 500 ° C is used as a high-quality array in current steel mills, and when it is used, it causes a decrease in the production efficiency or uses the same as using the steam for power generation in a thermal power plant. This is because it is necessary to install a new heat energy generating facility for replenishing the powder, and it becomes difficult to achieve the purpose of separating and recovering carbon dioxide at low cost.

However, in the case of using or utilizing a low grade array of 500 ° C. or lower generated from a steel mill in the process of separating carbon dioxide, for example, a high grade array or heat of combustion of fuel that is slightly above 500 ° C. so as not to affect the steel production process side. In the case of using some together, it is included in the technical scope of this invention.

In other words, the separation and recovery method of the present embodiment should not be interpreted in a narrow sense because only a low-quality arrangement of 500 ° C. or lower generated in a steel mill can be used or utilized in the process of separating carbon dioxide.

The separation and recovery method can also utilize a high-quality arrangement exceeding 500 ° C and the heat of combustion of fuel in a range not departing from the scope of the object of the present invention.

Examples of low-grade arrays of 500 ° C. or lower generated in steel mills include, for example, arrays from a sintered product cooler (about 350 ° C.), sintered exhaust gas (about 280 ° C.), hot stove exhaust gas (about 230 ° C.), and sintered main exhaust. Although low grade heat energy which is difficult to use can be mentioned in steelmaking processes, such as gas (about 180 degreeC) and wastewater used for blast furnace slag crushing (about 90 degreeC), It is not necessarily limited to these.

In current steel mills (steel plants), high-purity hydrogen is recovered using a steam reforming unit for combined use of oxygen combustion to reform steam from hydrogen by-product gas from COG or LDG, which is a by-product gas, and exhaust gas after hydrogen recovery. The use of gas is becoming more advanced and complex, such as for use in converters in steel plants.

Therefore, the low quality arrangement | sequence which generate | occur | produces through the facilities assembled in a steelworks (steel plant to process) is also included in the low quality arrangement | sequence of the separation collection method of this embodiment. For example, it is preferable to use or utilize a low quality array below the array temperature from the sintered product cooler. Exceeding the array (about 350 ° C.) temperature from the sintered component cooler is already used effectively as a high-quality heat source in the steel plant, where the current energy recovery technology has been advanced even though it is based on the construction of the steel mill.

In addition, the specific temperature (value) is not prescribed | regulated with respect to an arrangement | sequence temperature, The distance which carries the setting conditions in a sintering component cooler, or the process from an sintering component cooler to the process (to facility) which separates and collects carbon dioxide by chemical absorption method. This is because the temperature at the time of use for use or utilization in the process of separating and recovering carbon dioxide by the chemical absorption method fluctuates slightly due to changes in outside air temperature.

More preferably, steam heating is carried out using or utilizing a high temperature arrangement so that the heating temperature of the chemical absorption liquid in the regeneration tower is about 120 ° C. This is because the larger the temperature difference between the chemical absorbing liquid and the array, the smaller the equipment required for heat exchange can be, and further, the cost of separating and recovering CO ₂ can be reduced.

In addition, the use or utilization of such a low quality array may be directly used as a heating medium (heat energy) for using the low quality array for heating of a regeneration tower, and a heating medium (for example, steam) may be used. This is because it may be used to maintain the heating at a temperature.

The former (directly used) is preferable at the point of a simple device structure and low heat loss, and the latter (utilization) is preferable at the point of the controllability which keeps the chemical absorption liquid of a regeneration tower at a constant temperature.

When passing low-grade arrays through a heating medium, these corrosion-related components and impurities are removed so that the heat transfer rate does not decrease by corrosion or impurity deposition in the piping due to corrosion components or impurities contained in the low-level array (drainage or exhaust gas). It is desirable to put it.

In the separation and recovery method of the present embodiment, the low quality array (heat energy) may be used or utilized alone (as a simple array), or two or more types of low quality arrays may be used or used in combination. When heating a heating medium to predetermined temperature using two or more types of low quality arrangements together, you may boost up two or more types of low quality arrangements from low temperature. At this time, if thermal energy is insufficient at the end, the fuel may be burned.

That is, the separation recovery method of the present embodiment is not necessarily limited to the case of using or utilizing only a low quality array in the process of separating and recovering carbon dioxide by chemical absorption method, and for self-consumption in city steel, etc. It is also possible to use a part of the fuel gas sold as an auxiliary fuel.

This embodiment is briefly described with reference to the drawings. In addition, in FIGS. 2-4 shown below, the same code | symbol is attached | subjected about the apparatus similar to FIG. 1 or FIG.

FIG. 2 is the total amount (or part) of the heat required for the regeneration of the chemical absorbing liquid, using the arrangement generated in the steel mill, and the carbon dioxide produced by the chemical absorption method from the source gas generated in the steel mill (in FIG. 2, an example of by-product gas). Is a diagram schematically illustrating a process of separating and recovering a.

In the embodiment shown in Fig. 2, the by-product gas 3 and the chemical absorbing liquid 5 of the raw material gas containing carbon dioxide are absorbed in the absorption tower 1 using chemical absorbing liquid 5 such as amines at around room temperature (e.g., For example, after contacting at about 50 ° C. and absorbing carbon dioxide into the chemical absorption liquid 5, the liquid is transferred to the regeneration tower 7 and heated to a predetermined regeneration temperature (for example, around 120 ° C.). When heating by using a), as the total amount of heat required for the regeneration of the chemical absorbing liquid (5), by using or utilizing a low-quality array of 500 ° C or less (e.g., an arrangement from a sintered component cooler, etc.) generated in a steel mill The carbon dioxide 11 is separated and recovered from the chemical absorption liquid.

The low quality arrangement may be used to heat a heating medium 9 such as heating steam as described above, may be used directly as the heating medium 9, and the use or application form thereof is not particularly limited.

The by-product gas 13 after absorbing carbon dioxide into the chemical absorption liquid 5 in the absorption tower 1 is returned to the by-product gas piping 15 and used as a fuel gas in the process of a rear end. In addition, the chemical absorption liquid heated in the regeneration tower 7 and extracted with carbon dioxide is returned to the absorption tower 1 as the regeneration absorption liquid 5 '.

In addition, in this embodiment, although the example which utilizes or utilizes the low grade array below 500 degreeC produced by a steel mill as the total amount of heat required for the regeneration of a chemical absorption liquid was shown, This will be described with reference to FIG. 4.

Next, in the embodiment shown in FIG. 3, the by-product gas 3 and the chemical absorbing liquid 5 of the raw material gas containing carbon dioxide are absorbed in the absorption tower 1 in the vicinity of room temperature using the chemical absorbing liquid 5 such as amines. (For example, around 50 ° C), absorb carbon dioxide into the chemical absorption liquid, and then transfer the liquid to the regeneration tower 7 to heat the medium at a predetermined regeneration temperature (e.g., about 120 ° C). When heating using a), depending on the characteristics of the chemical absorbent liquid, boost up from a low temperature array in multiple stages (in FIG. Going.

That is, in the embodiment shown in Fig. 3, the lowest-quality array (for example, waste water used for crushing blast furnace slag (about 90 DEG C) or the like), and then the low-quality array (for example, Sintered main exhaust gas (approximately 280 ° C.), and the highest temperature low quality array (e.g., heat from sintered product cooler (approximately 350 ° C.), etc.) to utilize or utilize carbon dioxide (11) from the chemical absorption liquid. Separately recover.

The three kinds of low-definition arrangements may be used in order to heat the heating medium 9 such as heating steam as described above, or may be used sequentially as the direct heating medium 9, and the form of use or utilization thereof is It is not particularly limited.

The by-product gas 13 after absorbing carbon dioxide into the chemical absorption liquid 5 in the absorption tower 1 is returned to the by-product gas piping 15 and used as a fuel gas in the process of a rear end. In addition, the chemical absorption liquid heated in the regeneration tower 7 and extracted with carbon dioxide is returned to the absorption tower 1 as the regeneration absorption liquid 5 '.

In the present embodiment, the term "according to the characteristics of the chemical absorbent liquid" varies depending on the characteristics of the chemical absorbent liquid to be used, and the amount of heat required for regeneration of the chemical absorbent liquid varies greatly. This is because it is necessary to fully consider this point. In addition, it is preferable to consider this point similarly in other embodiment.

In addition, FIG. 4 schematically shows a process for separating and recovering carbon dioxide from a source gas generated in a steel mill by chemical absorption method while utilizing an arrangement generated in a steel mill for regeneration of a chemical absorbent liquid. One drawing.

In the embodiment shown in Fig. 4, the by-product gas 3 and the chemical absorbing liquid 5 of the raw material gas containing carbon dioxide are absorbed in the absorption tower 1 using the chemical absorbing liquid 5 such as amines in the vicinity of room temperature (e.g., For example, after contacting at about 50 ° C. and absorbing carbon dioxide into the chemical absorption liquid, the liquid is transferred to the regeneration tower 7 to transfer the heating medium 9 to a predetermined regeneration temperature (eg, around 120 ° C.). When used for heating, use or utilize low-quality arrays (e.g., arrays from sintered coolers, etc.) of 500 ° C or less generated in steel mills as much as possible for regeneration of chemical absorbent liquids. To recover the carbon dioxide (11) from the chemical absorption liquid.

In this embodiment, as much as possible, by using the low grade arrangement of 500 degrees C or less produced in a steel mill, the required amount of factory steam can be reduced. In addition, although FIG. 4 shows an example in which a low-quality array of 500 ° C. or lower generated in a steel mill is conveniently used in one step, an arrangement from the sintered product cooler is shown in one step. However, as shown in FIG. Of course.

The low quality arrangement may be used to heat a heating medium 9, such as heating steam, as described above, or may be used directly as the heating medium 9, and its use or application form is not particularly limited.

In addition, factory steam etc. may be utilized as a direct heating steam (heating medium 9), and may be utilized for heating the heating medium 9. As shown in FIG.

The by-product gas 13 after absorbing carbon dioxide into the chemical absorption liquid 5 in the absorption tower 1 is returned to the by-product gas piping 15 and used as a fuel gas in the process of a rear end. In addition, the chemical absorption liquid heated in the regeneration tower 7 and extracted with carbon dioxide is returned to the absorption tower 1 as the regeneration absorption liquid 5 '.

In this embodiment, "as much as possible" means the amount of heat required for regeneration of the chemical absorbent liquid after use or utilization of all low-grade arrays of 500 ° C or lower generated in steel mills that can be used or utilized as shown in FIG. This is because some shortages occur.

In such a case, the use of factory steam is because use (exclusive) of factory steam, which is actually used a lot in steel mills, is the most simple and inexpensive.

However, the present invention does not exclude the use of a heat source such as an arrangement other than factory steam, and other arrangements can be used as long as it does not impair the object of the present invention.

In addition, in the present invention, it is sufficient to use or utilize a low-grade arrangement of 500 ° C. or lower generated in a steel mill in the process of separating and recovering carbon dioxide by a chemical absorption method, and the present invention provides the heat energy required for heating in the regeneration tower described above. It should not be limited to only use or use in

In other words, although it is preferable to use or utilize the low-grade arrangement as the heat energy required for heating in a regeneration tower which is the dominant factor of operating cost, the chemical absorption, which is the separation and recovery method of carbon dioxide, which is currently being developed and spread most The law is not limited to the process principle (device configuration) shown in FIG.

In the process actually used, not only heating in a regeneration tower but also heat exchange and heating may be required, and a low quality arrangement of 500 degrees C or less generated in a steel mill may be used or utilized for such a part.

The separation and recovery process of carbon dioxide using the chemical absorption method applicable to the separation and recovery method of the present embodiment may satisfy the requirement of "Use or utilize a low-grade array below 500 ° C generated in steel mills", and in particular, It should not be limited to any process.

Therefore, after absorbing carbon dioxide into a chemical absorption liquid from a source gas containing carbon dioxide (by-product gas generated from a steel mill or its combustion exhaust gas), the type of chemical absorption liquid used in the process of heating the chemical absorption liquid to separate carbon dioxide, The concentration and liquid amount, the device configuration of the process, the conditions such as temperature and pressure in the process, various control methods, etc. are already known as separation recovery techniques of carbon dioxide using a chemical absorption method, and many improvements have been made. However, the separation recovery method of the present embodiment can be applied to include such an improved technique.

In addition, since these techniques are published in many well-known documents and patent publications, detailed description here is abbreviate | omitted.

(Use method of by-product gas after carbon dioxide extraction)

Although the above-mentioned ironworks by-product gas differs in calorie value, all of the iron-based by-product gas is already used as heat as fuel in the plant. Among these, when carbon dioxide is first extracted from BFG and reused as a process gas, there are a method of using 1) fuel of a gas turbine, 2) reinjection into a blast furnace, and 3) utilization as a return steel manufacturing process.

In the use method of 1) above, the calorific value of BFG is increased from 750 to 1000 kcal / Nm 3, thereby eliminating the need to add auxiliary fuel such as light oil. In addition, in the use method of 2), by re-injecting into the blast furnace, it can contribute to the reduction reaction of iron chemically reached to equilibrium as carbon dioxide is lost, it is possible to reduce the amount of coke used as a reducing agent.

In addition, in the use method of 3), the use amount of natural gas or coal can be reduced by using the reducing gas in the process of preliminarily reducing iron ore at the front end of the blast furnace using natural gas or coal.

As described above, when carbon dioxide is extracted and reused as a process gas, a useful effect can be expressed as compared with the current use of heat in a cow. These effects are excellent in that they can be used usefully, which are not obtained from exhaust gases that have been dissipated in the atmosphere by extracting carbon dioxide from combustion exhaust gases in which conventional fossil fuels are air-fired.

In addition, when hydrogen is produced by reforming COG or LDG, it is possible to reduce the hydrogen production cost by extracting carbon dioxide which is unnecessary in the meantime. In addition, when COG or LDG is used as a fuel in a furnace, the same effect as that obtained when carbon dioxide is extracted from the BFG and reused as a process gas can be obtained.

(How to Use Separated and Recovered Carbon Dioxide)

For the purpose of mass immobilization, the carbon dioxide separated and recovered is considered to be stored in the ground or in the ocean, such as aquifers or depleted natural gas fields, mainly in the global environment industrial technology research organization. In addition, the use of EOR (petroleum forced recovery method) and ECBM (forced recovery of coal-stored methane gas) has also begun to be carried out overseas. In addition, even in a water-soluble natural gas field, carbon dioxide can be injected and immobilized for forced recovery of natural gas.

Among them, in the case of storage in the ground or the ocean such as aquifers or depleted natural gas fields for the purpose of mass immobilization, carbon dioxide is not valuable and the recovery cost is preferably as low as possible. In this regard, carbon dioxide can be separated and recovered at a lower cost than carbon dioxide separated and recovered from the combustion exhaust gas of a conventional power plant.

On the other hand, although it is about 10,000 t / year per steel mill, carbon dioxide is used as a floor blower for steel mill converters, and the carbon dioxide separated and recovered is used instead of currently purchased on the market. By doing so, carbon dioxide emissions can be reduced.

Next, a second embodiment of the present invention relates to a method and apparatus for separating and recovering carbon dioxide from a carbon dioxide source.

Separation and recovery of carbon dioxide is a device for separating and recovering carbon dioxide from a carbon dioxide generating source, using a carbon dioxide absorption facility for absorbing carbon dioxide from a carbon dioxide-containing gas of the carbon dioxide generating source, and a heat source for regenerating the absorption medium from the absorption medium absorbing carbon dioxide. Is provided with an absorption medium regeneration facility for regenerating the absorption medium by separating the gas, a carbon dioxide absorption medium circulating between the two facilities as a transport medium of carbon dioxide, a delivery pipe and a return pipe for the transportation of the carbon dioxide absorption medium, In addition, the carbon dioxide absorbing equipment is installed in close proximity to the carbon dioxide generating source, characterized in that the absorption medium regeneration equipment is installed in a different place than the carbon dioxide generating source.

In addition, the separation and recovery method of carbon dioxide is a method of separating and recovering carbon dioxide from a carbon dioxide source, and absorbing carbon dioxide from a carbon dioxide-containing gas supplied from the carbon dioxide source using a carbon dioxide absorption medium to a carbon dioxide absorption facility close to the carbon dioxide source, and then regenerating the absorbent liquid. The carbon dioxide absorbing medium is heated using a heat source for heat, and the carbon dioxide is separated into an absorption liquid regeneration facility at a different place from the carbon dioxide absorption facility.

In the embodiment of this separation recovery method and apparatus, the carbon dioxide can be separated and recovered efficiently and inexpensively by combining the carbon dioxide generating source and the absorbent liquid regeneration heat source at different locations.

For example, by combining adjacent thermal power plants (carbon dioxide generators) and heat sources (absorbent liquid regeneration heat sources) in steel mills, it is possible to make the separation of carbon dioxide cheaper than in the prior art.

In this embodiment, although the chemical absorption method can be used similarly to 1st embodiment, it does not restrict | limit to these, You may use the separation-recovery method of carbon dioxide which requires another heat | fever. As the separation recovery method, since the chemical absorption method is preferable, the chemical absorption method will be described below. In addition, although this embodiment is described in detail using drawing, this embodiment is not restrict | limited to what was shown.

5 to 9 show an apparatus (process) for separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at different locations. In these drawings, like reference numerals denote like elements for the same apparatus, and the description thereof may be omitted in FIG. 6 and later to avoid duplication.

As shown in Fig. 5, the apparatus 50 for separating and recovering CO ₂ from the CO ₂ generating source of the present embodiment is a CO ₂ absorbing medium 57 from a CO ₂ containing gas supplied from a CO ₂ generating source 53 through a pipe. ) to the CO ₂ absorption plant (53) for absorbing CO ₂ by, CO ₂ the intake suhan CO ₂ absorbent medium 55 to remove the CO ₂ by using a heat source (63) for absorbing medium reproduced from the CO ₂ absorption and the absorbent media playback equipment 61 and, CO ₂ absorption medium (57) circulating in the CO ₂ absorption equipment 53 and the CO ₂ absorption plant (53) between a transport medium of the CO ₂ for reproducing the medium, CO ₂ A delivery pipe 59 and a return pipe 65 for transporting the absorption medium 57, and the CO ₂ absorption facility 55 is provided in proximity to the CO ₂ generating source 53, and the absorption The medium regeneration facility 61 is provided in a place different from the CO ₂ generating source 53.

Therefore, the method for separation and recovery of CO ₂ from the CO ₂ source of the present embodiment using the above apparatus 51, CO as close to CO ₂ absorption equipment 55 to the CO ₂ source to be supplied from the CO ₂ source (53) ₂ from containing gas, after absorption of CO ₂ by the CO ₂ absorption medium (57) to cycle through the CO ₂ absorption equipment 55 and the absorbing solution regeneration plant (61) as the transport medium (57) of CO _2, CO ₂ is sent to the absorbent liquid regeneration facility 61 through a delivery pipe 59 for transport of the absorbent medium 57, and the CO ₂ absorbent medium 57 is heated using the heat source 63 for regeneration of the absorbent liquid, thereby generating a CO ₂ source. and is to cycle by separating the CO ₂ absorbing solution in playing equipment (61) elsewhere and returned to the CO ₂ absorption equipment 55 in the return pipe 65 for the transport of CO ₂ absorption medium (57).

(Plant to which the separation collection method and apparatus of the present embodiment are applicable)

Examples of the plant to which the separation recovery method and apparatus of the present embodiment can be applied include, but are not limited to, a steel mill, a thermal power plant, a cement mill, and the like having a large CO ₂ generation source.

This embodiment is also applicable to a plant having a large-scale CO ₂ generation source other than the steel mill described in the first embodiment.

For example, a combination of carbon dioxide sources (eg, from a thermal power plant) and absorbent regeneration heat sources (arrangements from plants other than those adjacent to a thermal power plant) can be provided efficiently and inexpensively. .

(CO2 generation source)

As the carbon dioxide generating source in the present embodiment, similarly to the first embodiment, a facility for generating carbon dioxide in the plant and a pipe for transporting the carbon dioxide-containing gas from the facility to the next step are applicable.

In addition, when discharging without transporting to the next process, discharge equipment (chimney etc.) shall also be included in a carbon dioxide generating source. As a facility for generating carbon dioxide, a blast furnace integrated steelworks is taken as an example, blast furnaces, coke furnaces, converters, and the like, and cement kilns, for example, cement kilns, etc., but is not limited to these.

In addition, when the blast furnace integrated steelworks are taken as an example, although blast furnace gas (BFG) piping, coke oven gas (COG) piping, converter gas (LDG) piping, etc. are applicable, it does not have to restrict to these in any way.

[CO2-containing gas (raw material gas)]

The carbon dioxide-containing gas referred to in the present embodiment may be a carbon dioxide-containing gas generated from a carbon dioxide generating source. For example, in the case of the steel mill, the carbon dioxide-containing gas may also vary depending on the configuration thereof. By-product gas (unburned gas) such as gas (COG) and converter gas (LDG), but also gas (process gas) produced during the process (process) of reforming the by-product gas such as COG or LDG for hydrogen production purposes. Included.

In this embodiment, the combustion exhaust gas of the by-product gas may be a carbon dioxide-containing gas (raw material gas). In addition, in cement plants, for example, suspension-free heater outlet gas, electrostatic precipitator outlet gas, and the like correspond to combustion exhaust gas and the like in a thermal power plant, but the present invention is not limited to these.

When source gas (by-product gas and combustion exhaust gas which generate | occur | produce from a carbon dioxide generation source) is available as a high quality array, it is preferable to use what is after use. It is because the temperature at the time of carbon dioxide absorption should just be a temperature near normal temperature.

Each of the source gases may be used alone or in combination with each other to separate and recover carbon dioxide. The two or more types of mixed forms include not only mixed forms of by-product gases and mixed forms of combustion exhaust gases of by-product gases, but also mixed forms of combustion exhaust gases of by-product gases and by-product gases.

In other words, in the present embodiment, a plurality of carbon dioxide absorption facilities can be provided in proximity to a plurality of carbon dioxide generating sources to handle a plurality of source gases.

The concentrations of CO ₂ of BFG, COG, LDG, and the like in the source gas are the same as those described in the first embodiment, and thus the description thereof is omitted.

The CO ₂ concentration of the suspension free heater outlet gas generated in the cement mill is about 14 volume%, and the CO ₂ concentration of the electrostatic precipitator outlet gas is about 9 volume%. In addition, the CO ₂ concentration of the combustion exhaust gas generated in the thermal power plant is from several to tens of volume percent.

In this embodiment, any source gas among them can be suitably used. As the source gas, a source gas having a high carbon dioxide concentration is preferable, and it is preferable to use a combustion exhaust gas of BFG, BFG, a combustion exhaust gas of COG, a combustion exhaust gas of LDG, and a mixed gas of these gases with other gases.

Moreover, the gas produced | generated in the process of producing hydrogen by reforming COG and LDG mentioned later can also be used suitably. In the case where carbon dioxide is separated and recovered from the source gas having a high carbon dioxide concentration by means such as a chemical absorption method, the same effects as described in the first embodiment can be obtained.

As the CO ₂ absorption medium, the same chemical absorbing liquid as that described in the first embodiment can be used, and it is not particularly limited.

As a carbon dioxide absorption facility for absorbing carbon dioxide, although the same thing as the absorption tower demonstrated in 1st Embodiment can be used, it does not need to restrict especially to these.

As the absorption medium regeneration equipment for regenerating the absorption medium by separating carbon dioxide from the absorption medium absorbing the carbon dioxide by using the heat source for regenerating the absorption medium, the same regeneration tower as that described in the first embodiment can be used, but it should be particularly limited thereto. It is not.

The delivery pipe and the return pipe are provided between the facilities for transporting the carbon dioxide absorption medium circulating between the carbon dioxide absorption facility and the absorption medium regeneration facility.

It is preferable to use a process arrangement as a heat source for regenerating the absorption medium. Specifically, it is an arrangement generated in a steelmaking process or an arrangement generated in a cement manufacturing process, and preferably a low-quality arrangement of 500 ° C. or lower, more preferably 400 ° C. or lower, but is not limited thereto. Among these, the arrangement generated in the steelmaking process is the same as that described in the first embodiment, and thus the description thereof is omitted.

Examples of the arrangement generated in the cement manufacturing process include the exhaust gas of the suspension free heater (about 380 ° C.), the cooler cooler exhaust gas (about 350 ° C.), and the electrostatic precipitator outlet exhaust gas (about 200 ° C.). It should not be limited to these.

In this embodiment, the case where the combustion heat of fuel is utilized or utilized in part as a heat source for regeneration of an absorption medium is also included in the technical scope of the present invention.

As the heat source for the absorption medium regeneration, the steelmaking process may include, for example, a sintered feature cooler, a hot blast furnace, a blast furnace slag cooling device, a sintering furnace, and the like (see the first to fifth embodiments described later), and also cement production. The process may include a suspension free heater, a cooler cooler, an electrostatic precipitator and the like, but it should not be limited to these.

That is, in this embodiment, as shown in FIG. 6, it is preferable to use the process arrangement 63a as a part (or all) of the heat source for absorption liquid regeneration.

As described in the first embodiment, carbon dioxide is separated by using or utilizing low-grade heat energy (which is preferably used or utilized as high as possible in low-grade heat energy) that is difficult to use in steel mills or cement mills. This is because the recovery cost can be greatly reduced.

In addition, the low quality arrangement of 500 degrees C or less is preferable as the heat source for absorption liquid regeneration for the same reason as described in 1st Embodiment.

In this embodiment, one heat source may be used alone or utilized as the heat source for regenerating the absorption medium, or two or more types of heat sources may be used or used in combination. When using together and heating a heating medium to predetermined temperature, you may boost up two or more types of arrangement from low temperature, for example. At this time, if thermal energy is insufficient at the end, the fuel may be burned.

That is, this embodiment is not necessarily limited to the case where it uses or utilizes only a process arrangement for the process of isolate | separating and recovering carbon dioxide by a chemical absorption method. In this embodiment, in addition to self-consumption in an iron making plant, it is also possible to use a part of fuel gas sold for city gas etc. as an auxiliary fuel. Such an example is the same as that described with reference to Figs. 2 to 4 in the first embodiment, and the description thereof is omitted here.

Next, in the present embodiment, the carbon dioxide absorption facility is provided in close proximity to the carbon dioxide generating source, and the absorption medium regeneration facility is provided at a different location from the carbon dioxide generating source.

In the present invention, since the chemical absorption liquid is used as the absorption medium, the power for transferring the medium is overwhelmingly reduced compared to the source gas (gas) even when the piping distance is increased. On the other hand, when the carbon dioxide generating source and the carbon dioxide absorbing equipment are installed in another place without dropping (dropping), the raw material gas supply piping distance for supplying the raw material gas to the CO ₂ absorption equipment becomes long, so that the gas serving as the transport medium. The power for conveying is overwhelmingly large compared to the case for conveying liquid.

As an installation place of an absorption medium regeneration facility different from the installation place of a carbon dioxide generation source, it is preferable that it is specifically the vicinity of the heat source for absorption medium regeneration. This increases the piping distance for arranging the heating medium (process waste gas, combustion gas, etc.) from the heat source for absorbing medium regeneration to the absorption medium regeneration facility, thereby preventing the temperature from being lowered and the thermal efficiency during the transportation of the heating medium. To do this.

That is, when combining a carbon dioxide generating source and an absorption medium regeneration heat source in another place, the carbon dioxide absorption facility is brought close to the carbon dioxide generating source so that the arrangement distance of the piping of the raw material gas which requires a larger transportation power than the absorption medium (absorption liquid) is required. It is possible to shorten and arrange the absorption medium (absorption liquid) between the carbon dioxide absorption facility and the absorption medium regeneration facility in another place, so that the carbon dioxide can be separated and recovered efficiently and inexpensively.

Also, the proximity of the absorption medium regeneration facility to an absorption medium regeneration heat source at another location is closer to the absorption medium regeneration facility closer to the carbon dioxide generating source, and the regeneration of the heating medium from the heat source for regeneration of the absorption medium at another location. The distance for arranging the heating medium of the molten heat source through the pipe can be shortened significantly, and the temperature of the heat source can be suppressed from being lowered, so that carbon dioxide can be separated and recovered efficiently and inexpensively.

Specifically, the distance (A) between the carbon dioxide generating source and the carbon dioxide absorption facility, the distance (B) between the absorption medium regeneration facility and the heat source for regenerating the absorption medium, and the distance (C) between the carbon dioxide absorption facility and the absorption medium regeneration facility. It is preferable that A < C and B < C satisfy the relational expression (see, for example, FIGS. 10 to 14).

In the case where the carbon dioxide absorption facility and the absorption medium regeneration facility are in a 1: 1 relationship, the above is the same as above. It is desirable to satisfy all of the relationships.

In addition, when the process array of a different temperature level is provided in multiple stages as a heat source for absorption medium regeneration, let B be the distance between an absorption medium regeneration facility and the highest heat source of a temperature level (for example, FIG. 12). And FIG. 14).

More specifically, the piping distance X for supplying the carbon dioxide-containing gas from the carbon dioxide generating source to the carbon dioxide absorption facility, the delivery piping distance Y and the return piping distance Z of the carbon dioxide absorbing medium is 2X <( It is preferable to satisfy the relation of Y + Z, or the piping distance W for supplying heat (for example, process exhaust gas or combustion exhaust gas of fuel) from the heat source for absorbing medium regeneration to the absorption medium regeneration facility. More preferably, the relationship of (X + W) <(Y + Z) is satisfied.

Also in this case, when a process array of different temperature levels is provided in multiple stages as the heat source for absorbing medium regeneration, the piping distance between the absorbing medium regeneration facility and the heat source having the highest temperature level is W (for example, FIG. 12 and FIG. 14).

In this embodiment, one or more carbon dioxide absorption facilities and one or more absorption liquid regeneration facilities may be provided. For example, in the case where there are a plurality of carbon dioxide generating sources, the carbon dioxide absorption facilities may be provided in proximity to these. Similarly, when the process arrangement which can be used as the heat source for absorbing medium regeneration is divided into plural parts, the absorbing medium regeneration equipment may be provided in proximity to these.

In other words, the carbon dioxide absorbing equipment and the absorbent liquid regeneration equipment may have any one of the relations of 1: 1, Da: 1, 1 :: 1, Da: C. In addition, it is preferable to aggregate in terms of equipment cost and operating cost.

For example, as shown in Fig. 7, as shown in Fig. 7, two carbon dioxide absorbing facilities 55a and 55b are provided close to each of the two carbon dioxide generating sources 53a and 53b, respectively, and independent delivery pipes are provided. Between the 59a, the return pipe 65a, the delivery pipe 59b, and the return pipe 65b are different from these, specifically, one absorption liquid regeneration facility 63 provided in proximity to the regeneration heat source 63. It is installed.

7 shows an example in which the delivery pipe and the return pipe are independently formed in two systems, the two medium pipes are integrated into one system in the middle, and the absorption medium 57 is transported to one absorption liquid regeneration facility 63. In addition, when returning to the two carbon dioxide absorption facilities 55a and 55b, it may distribute to two systems again.

In addition, the case where a plurality of carbon dioxide absorption facilities and absorbent liquid regeneration facilities are provided is, for example: As shown in FIG. 8 as an example, the three carbon dioxide generating sources 53a to 53c are located close to each other. Absorption medium regeneration facilities 61a and 61b are provided near the places where the carbon dioxide absorption facilities 55a to 55c are different from each other, specifically, the regeneration heat sources 63a and 63b.

In this case, as the discharge pipe and the return pipe which are installed between both facilities, the three discharge pipes 59a to 59c and the return pipes 65a to 65c which are connected to the three carbon dioxide absorption facilities 55a to 55c are separated from each other. By integrating and redistributing, the two delivery pipes 59d to 59e and the return pipes 65d to 65e may be connected to the respective absorption medium regeneration facilities 61a to 61b.

In such a case, when the CO ₂ absorption capacity required for the three carbon dioxide absorption facilities, for example, the amount of source gas handled by each carbon dioxide absorption facility or the concentration of CO ₂ in the gas is different, the corresponding absorption medium amount can be supplied. What is necessary is just to adjust the piping diameter (area) of the delivery piping 59a-59c and the return piping 65a-65c, and the transport capacity of a transport pump.

Specifically, when the carbon dioxide absorption amount of each of the carbon dioxide absorption facilities 55a: 55b: 55c becomes 5: 3: 2, for example, the delivery pipe {59a: 59b: 59c (return piping (65a: 65b: 65c)). ]}, The piping area and the transport capacity may also be 5: 3: 2.

Similarly, when the regeneration capacity of the two absorption medium regeneration facilities, for example, the heat source for regenerating the absorption medium used in each of the absorption medium regeneration facilities, is different, the pipe diameter (area) and the size of the corresponding absorption medium can be supplied. You can adjust the transport capacity.

Specifically, in the case where the heat source amount for absorption medium regeneration supplied to each of the absorption medium regeneration facilities 61a: 61 is 6: 4, for example, the delivery pipe {59d: 59e (return piping 65d: 65e)]} The piping area and the transport capacity of s may also be 6: 4.

In addition, in this embodiment, you may provide the process arrangement | sequence of a different temperature level in multiple stages as a heat source (part or all) for absorption liquid regeneration. This is the same as described in the first embodiment (see Fig. 3).

Moreover, also in any of 1st Embodiment and this embodiment, the heating which heats an absorption medium using the heat source for absorption liquid regeneration is not restrict | limited the heating which heats the absorption medium in a direct absorption medium regeneration facility, And the absorption medium may be heated in a multistage process array of different temperature levels in the absorption medium regeneration facility.

At this time, as shown in Fig. 9, it is preferable to boost up from a low temperature process arrangement. In other words, when the heat source which can be used as these regeneration heat sources is scattered in multiple site | parts, as shown in FIG. 9, a delivery piping may be arrange | positioned so that it may pass in the vicinity of these heat sources, and may be used as a regeneration heat source.

At this time, may go to temperatures up boost from low process arrangement, the temperature is low, heat source process array (63a) [ten won temperature (T _1)] from the look-process array (63b) of the high temperature ten won [ten won temperature ( T ₂ )] in that order so that the delivery pipe passes.

In addition, the absorption medium regeneration facility 61 is provided in the vicinity of the process array 63c (heat source temperature T ₃ ) which is the heat source having the highest temperature. Where T ₁ <T ₂ <T ₃ . As a result, in the course of passing the absorbent liquid through the delivery pipe 59, the absorbent medium is gradually preheated to a high temperature and transferred to the absorbent medium regeneration facility 61, where the amount of heat required for regeneration is supplied to separate carbon dioxide.

The absorption medium passing through the delivery pipe is usually a liquid, but when the delivery pipe is heated using a heat source as described above, it can be transported in a state of partially vaporizing or containing gas separated from carbon dioxide gas from the absorption medium. In some cases, from the viewpoint of reducing the transportation power, it is preferable that the heat source used for heating the delivery pipe has a temperature such that the absorption medium does not vaporize or the carbon dioxide separates.

In other words, as an absorption medium, it is preferable that density is higher than gas alone, and especially a liquid is preferable. As long as it is in the range which does not give a significant influence to a transportation power, it may be what has a solid and a gas in a part of liquid.

Moreover, also in any of 1st Embodiment and this embodiment, you may cool the absorption medium in a return piping using a cold heat source for a return piping. That is, it is preferable that the absorption medium in a return piping is cooled at low temperature rather than returning to a carbon dioxide absorption facility from the point of absorption efficiency of carbon dioxide.

Normally, as shown in Figs. 1 to 4 of the first embodiment, heat is exchanged and cooled between the absorption mediums in the delivery pipe. However, in a large-scale plant such as a steel mill, a cold heat source may be used in abundance. Some may be available.

However, in the present invention, since the carbon dioxide absorption facility and the absorption medium regeneration facility are located at different locations (distant locations), they are cooled to near the outside air temperature by natural cooling. Therefore, it is particularly effective to use the cold heat source when the outside air temperature is high, such as summer.

The above is description of this embodiment. Specific examples will be briefly described below with reference to the drawings, but the present invention should not be limited to these.

10 to 13 schematically show specific examples of separating and recovering carbon dioxide by combining a carbon dioxide generating source and an absorbent liquid regeneration heat source at different places.

In addition, in these figures, the same code | symbol is attached | subjected about the component requirements of the same apparatus, etc., and the description may be abbreviate | omitted after FIG. 11 in order to avoid duplication.

(1st specific example)

The CO ₂ separation recovery apparatus 100 shown in FIG.

CO ₂ causes BFG main 93 from for absorbing CO ₂ by the CO ₂ absorption medium (97) from the BFG (CO ₂ concentration of 20 to 25% by volume) of CO ₂ containing gas supplied through the pipe 94, A CO ₂ absorption plant (also simply called an absorption tower) 95,

Absorption medium regeneration plant (playback using the sinter cooler arrangement (250 ℃ to 350 ℃), a heat source-absorbing medium playback by separating the CO ₂ from the absorbing medium (97) that has absorbed the CO ₂ to reproduce the absorption medium (97) Top) 101,

An absorption medium 97 circulating between the absorption tower 95 and the regeneration tower 101 as a transport medium of CO ₂ , and

A delivery pipe 99 and a return pipe 105 for transporting the absorption medium 97, and

The absorption tower 95 is installed close to the BFG main building 93, and the regeneration tower 101 is different from the BFG main building 93, in particular, to the sinter cooler 103a which is a heat source for regeneration of the absorption medium. It is installed.

Therefore, the CO ₂ separation and recovery method using the apparatus 100 is an absorption tower 95 as a transport medium of CO ₂ from BFG supplied from the BFG main pipe 93 in the absorption tower 95 close to the BFG main pipe 93. After absorbing CO ₂ using the absorption medium 97 circulating between the regeneration tower 101 and the regeneration tower 101, the absorption medium 97 is regenerated in the delivery pipe 99 for transporting the absorption medium 97. 101, and the absorption medium 97 is heated using a sinter cooler array, and CO ₂ is separated from the regeneration tower 101 at a different location from the BFG main building 93 to transport the absorption medium 97. Return to the absorption tower (95) from the return pipe 105 for use in circulation.

Here, the distance X of the pipe 94 for supplying BFG from the BFG main pipe 93 to the absorption tower 95 = the distance A between the BFG main pipe 93 and the absorption tower 95, and the sinter cooler. The distance W of the pipe 96 for supplying the sinter cooler array from the 103a to the regeneration tower 101 = the distance B between the sinter cooler 103a and the absorption tower 95, and the delivery pipe 99 Distance (Y) = distance (Z) of return pipe 105 = distance (C) between absorption tower 95 and regeneration tower 101, and their relationship is 2X <(Y + Z) , (X + W) <(Y + Z) and A <C are also configured to satisfy both B <C.

The BFG generated in the blast furnace is supplied as fuel gas to the self-powered power plant in the steel mill or the adjacent thermal power plant through the BFG main building, and here, a valve is installed in the BFG main building, and part or all of the BFG is separated from the CO ₂ separation and recovery apparatus 100. It is advantageous in that carbon dioxide can be removed to be supplied to a power plant or a thermal power plant as a fuel having high combustion efficiency (this can achieve the same effect as described in the first embodiment).

(2nd specific example)

The CO ₂ separation recovery apparatus 110 shown in FIG. 11 uses hot stove exhaust gas (150 ° C to 300 ° C) (part or all) as a heat source for absorbing the medium for regeneration, and the regeneration tower 101 regenerates the absorption medium. except that it is close to a heat source installed in the hot air for (103b), and the same configuration as that of the CO ₂ separation and recovery device 100 shown in FIG.

Therefore, in the CO ₂ separation recovery method using the apparatus 110, except that the absorption medium 97 is heated by using a hot stove exhaust gas, the CO ₂ separation recovery apparatus 100 shown in FIG. Same as the CO ₂ separation recovery method.

Here, the distance X of the pipe 94 = the distance A between the BFG main pipe 93 and the absorption tower 95, and supply the exhaust gas from the hot stove 103b to the regeneration tower 101. Distance (W) of the pipe (96) = heat weather path (103b) and the absorption tower (95) (B), the distance (Y) of the delivery pipe (99) = distance (Z) of the return pipe (105). ) = The distance (C) between the absorption tower 95 and the regeneration tower 101, and their relationship is 2X <(Y + Z), (X + W) <(Y + Z) and A < C is also configured to satisfy both B <C.

(3rd specific example)

The CO ₂ separation recovery apparatus 120 shown in FIG. 12 is an example in which a process arrangement of different temperature levels is provided in multiple stages (two stages) as part or all of the heat source for absorbing liquid regeneration.

Among the heat sources for absorbing medium regeneration, hot blast exhaust gas (150 ° C to 300 ° C) (part or all) as a heat source having a high temperature level, and high temperature chain slag drainage (60 ° C to 90 ° C) as a heat source having a low temperature level Is arranged so that the regeneration tower 101 is provided in close proximity to the hot blast furnace 103b which is a heat source for absorbing medium regeneration, and the delivery pipe 99 passes through a position close to the blast furnace crushing slag cooling device 103c. Except for that, the same configuration as the CO ₂ separation recovery apparatus 100 shown in FIG.

Therefore, the CO ₂ separation and recovery method using the apparatus 120 first heats (preheats) the absorption medium 97 in the delivery pipe 99 by using the blast-furnace slag drainage, and then absorbs it by using the hot blast exhaust gas. Except for heating the medium 97, it is the same as the CO ₂ separation recovery method using the CO ₂ separation recovery apparatus 100 shown in FIG.

Here, the distance X of the pipe 94 = the distance A between the BFG main pipe 93 and the absorption tower 95, and supply the exhaust gas from the hot stove 103b to the regeneration tower 101. Distance (W) of the pipe (96) = the hot air path (103b) and the absorption tower (95) (B), the distance (Y) of the delivery pipe 99 = distance (Z) of the return pipe (105). ) = The distance (C) between the absorption tower 95 and the regeneration tower 101, and their relationship is 2X <(Y + Z), (X + W) <(Y + Z) and A <C It is also configured to satisfy both B < C.

(4th specific example)

The CO ₂ separation and recovery system 130 shown in FIG. 13 is a combustion exhaust gas (CO ₂ concentration) that is a CO ₂ containing gas through a pipe 94a from a self-powered plant (joint thermal power plant) 93a in a steel mill that is a CO ₂ generation source. 8 to 2O% by volume) is a block of the same construction and that, with a CO ₂ separation and recovery device 100 shown in Figure 10 except for being supplied to the absorber (95).

Thus, the CO ₂ separation and recovery method using the apparatus 130 is characterized in that the absorption medium 97 is removed from the combustion exhaust gas supplied from the autonomous power plant 93a in the absorption tower 95 adjacent to the autonomous power plant 93a in the steel mill. Except for absorbing CO ₂ by use, the same method as the CO ₂ separation recovery method using the CO ₂ separation recovery apparatus 100 shown in FIG.

Here, the distance X of the pipe 94a is the distance A between the self-power plant 93a and the absorption tower 95, for supplying the sinter cooler array from the sinter cooler 103a to the regeneration tower 101. Distance W of pipe 96 = distance B between sinter cooler 103a and absorption tower 95, distance Y of delivery pipe 99 = distance Z of return pipe 105. = Distance (C) between absorption tower 95 and regeneration tower 101, and their relationship is 2X <(Y + Z), (X + W) <(Y + Z) and A <C B <C is configured to satisfy both.

In a power plant in a steelworks, thermal power generation can be performed using BFG or CO ₂ separated recovery apparatus of FIGS. 10 to 12 as fuel as BFG and heavy oil from which carbon dioxide has been removed. The CO ₂ concentration of 8 to 20% by volume of the combustion exhaust gas is an example of using ordinary BFG and heavy oil.

(5th specific example)

The CO ₂ separation and recovery device 140 shown in FIG. 14 is a combustion exhaust gas (CO ₂ concentration 8), which is a CO ₂ containing gas, from the thermal power plant 93b (the adjacent steel mill) to the CO ₂ generation source through a pipe 94b. 15% by volume) is supplied to the absorption tower 95, and is an example in which a process arrangement of steelworks at different temperature levels is provided in multiple stages (three stages) as a heat source for regeneration of the absorption liquid.

Sintered cooler array (250 ° C to 350 ° C) as the heat source having the highest temperature level among heat sources for regeneration of the absorption medium, and hot stove exhaust gas (150 ° C to 300 ° C) (part or all) as the heat source having the highest temperature level. Also, using the blast-furnace slag cooling water (60 ° C. to 90 ° C.) as a lower heat source of the temperature level, the regeneration tower 101 is sintered where the regeneration tower 101 is different from the thermal power plant 93b, specifically a heat source for regeneration of the absorption medium. It is provided in close proximity to the cooler 103a, and it is shown in FIG. 10 except that the delivery pipe 99 is arrange | positioned so that it may pass through the position which adjoins the blast furnace crushing slag cooling apparatus 103c and the hot air path 103b. the same configuration as that of the CO ₂ separation and recovery device (100).

Therefore, in the CO ₂ separation and recovery method using the apparatus 140, in the absorption tower 95 adjacent to the thermal power plant 93b adjacent to the steel mill, the absorption medium (from the combustion exhaust gas supplied from the thermal power plant 93b) 97) to absorb CO ₂ and to boost up from a low temperature process arrangement to obtain the blast-furnace crushing slag drain, followed by hot blast exhaust gas, to absorb the absorbent medium 97 in the delivery piping 99. After heating (preheating), the absorption medium 97 is heated using the sinter cooler array, except that the CO ₂ separation recovery method using the CO ₂ separation recovery apparatus 100 shown in FIG.

Here, the distance X of the pipe 94b = the distance A between the thermal power plant 93b and the absorption tower 95, for supplying the sinter cooler array from the sinter cooler 103a to the regeneration tower 101. Distance W of pipe 96 = distance B between sinter cooler 103a and absorption tower 95, distance Y of delivery pipe 99 = distance Z of return pipe 105. = Distance (C) between absorption tower 95 and regeneration tower 101, and their relationship is 2X <(Y + Z), (X + W) <(Y + Z) and A <C B <C is configured to satisfy both.

As the separation and recovery process (apparatus and method) of carbon dioxide using the chemical absorption method, which can be applied in the present embodiment, the above-described "carbon dioxide absorption facility is provided in proximity to the carbon dioxide generating source, and the absorption medium regeneration facility is carbon dioxide. It is not particularly limited as long as it satisfies the requirement that it is installed at a place different from the source ”.

Therefore, after absorbing carbon dioxide from a source gas containing carbon dioxide (by-product gas generated in a steel mill or its combustion exhaust gas) into a chemical absorption liquid, the type of chemical absorption liquid used in the process of heating the chemical absorption liquid to separate carbon dioxide, and the The concentration, liquid amount, device configuration of the process, conditions such as temperature and pressure in the process, various control methods, and the like are already known as separation and recovery techniques of carbon dioxide using a chemical absorption method, and numerous improvements have been made.

This embodiment can of course be applied as a separate recovery process including such an improved technique, but these techniques have been published in many known documents and patent publications, and thus detailed description thereof will be omitted.

(Use method of by-product gas after carbon dioxide extraction)

Since this is the same as that described in the first embodiment, the description thereof will be omitted.

(Utilization method of raw material gas after carbon dioxide extraction)

The raw material gas after the carbon dioxide extraction may be used in a cement factory or a thermal power plant other than an ironworks, in the same way as the by-product gas in an ironworks. If it is not available, it is exhausted without using it (see Figs. 13 and 14).

(How to Use Separated and Recovered Carbon Dioxide)

Since this is the same as that described in the first embodiment, the description thereof will be omitted.

As described above, the following effects can be obtained by the first embodiment of the present invention.

1) By separating and recovering carbon dioxide from the by-product gas (unburned gas) of a steel mill with a high carbon dioxide ratio compared with the combustion exhaust gas of a thermal power plant, a separation recovery facility can be made compact. Depending on the raw material gas to be used, for example, it is possible to reduce the equipment cost by 30% or more by using BFG of the steel mill as the raw material gas instead of the carbon dioxide low concentration combustion exhaust gas of a coal-fired power plant.

2) By using or utilizing low grade energy of 0 to 500 degreeC, preferably 350 degrees C or less in a steel mill, the operating cost of carbon dioxide separation | recovery collection by a chemical absorption method can be reduced. Specifically, the thermal energy required for heating the chemical absorption liquid in the regeneration tower used for the chemical absorption method is the dominant factor (about 5 to 80%) of the operating cost of the present method. Alternatively, it can be used to significantly reduce the overall operating cost.

3) By separating and recovering carbon dioxide from the by-product gas and its combustion exhaust gas, the thermal efficiency when using the by-product gas as a fuel at the rear end can be improved. Although based also on the raw material gas to be used, when BFG of a steel mill is used as raw material gas, for example, it can improve about 2 to 30%.

4) Furthermore, since the combustion exhaust gas after using the by-product gas (unburned gas) as a fuel gas has a higher carbon dioxide ratio, it is possible to further reduce the separation and recovery facilities of carbon dioxide, thereby reducing the amount of emission reduction of carbon dioxide from the steel mill (separation). Recovery amount) can be increased.

According to the second embodiment of the present invention, carbon dioxide can be separated and recovered from the carbon dioxide generating source efficiently and inexpensively by combining the carbon dioxide generating source and the absorbent liquid regeneration heat source located in another place.

According to the present invention, since the effect can be perfumed at once, carbon dioxide can be separated and recovered at a very low cost. Therefore, the present invention is an effective and useful technique that can be used industrially even in a steelmaking plant with high cost competition.

In addition, according to the present invention, it is also possible to use the recovered carbon dioxide as a reducing gas in top gas recycling in an ironworks, for example, a blast furnace. As a result, it is possible to reduce the reducing agent and also to significantly reduce the overall cost in the steel mill, such as reducing the amount of coke used and the amount of CO ₂ generated in the blast furnace (in some cases, reducing the cost). .

In addition, many techniques have been proposed as described above (including those newly discovered by the present inventors), and the present invention provides a combination of these techniques to reduce product cost. It is to provide a very useful technology that can restrain the rise (depending on the commodity value of carbon dioxide, the overall cost can be reduced) and contribute effectively to the prevention of global warming.

Claims (23)

It is a method of separating and recovering carbon dioxide from a by-product gas generated in a steel mill by a chemical absorption method, And absorbing carbon dioxide from the gas into the chemical absorption liquid, and then heating or using the chemical absorption liquid to separate the carbon dioxide, using or utilizing a low-grade array of 500 ° C. or less generated in a steel mill. It is a method of separating and recovering carbon dioxide by chemical absorption method from combustion exhaust gas of by-product gas generated in a steel mill, And absorbing carbon dioxide from the gas into the chemical absorption liquid, and then heating or using the chemical absorption liquid to separate the carbon dioxide, using or utilizing a low-grade array of 500 ° C. or less generated in a steel mill. It is a method of separating and recovering carbon dioxide by a chemical absorption method from the process gas produced in the reforming process for producing hydrogen from the by-product gas generated in the steel mill, And absorbing carbon dioxide from the gas into the chemical absorption liquid, and then heating or using the chemical absorption liquid to separate the carbon dioxide, using or utilizing a low-grade array of 500 ° C. or less generated in a steel mill. The method for separating and recovering carbon dioxide according to any one of claims 1 to 3, wherein the carbon dioxide concentration in the by-product gas, combustion exhaust gas, and process gas provided in the chemical absorption method is 15% by volume or more. The method for separating and recovering carbon dioxide according to any one of claims 1 to 3, wherein the by-product gas is at least one of blast furnace gas, coke oven gas, and converter gas. The method for separating and recovering carbon dioxide according to any one of claims 1 to 3, wherein an arrangement generated in a steel mill is used or utilized as the whole or part of the heat amount required for the regeneration of the chemical absorption liquid. The method for separating and recovering carbon dioxide according to any one of claims 1 to 3, wherein a suitable arrangement generated in the steel mill is used or utilized in multiple stages for regeneration of the chemical absorbent liquid depending on the characteristics of the chemical absorbent liquid. The method for separating and recovering carbon dioxide according to any one of claims 1 to 3, wherein the steam generated for the plant is used while utilizing or utilizing the arrangement generated in the steel mill as much as possible for the regeneration of the chemical absorption liquid. . delete delete delete delete delete delete delete delete delete delete delete delete delete delete The method for separating and recovering carbon dioxide according to claim 4, wherein the by-product gas is at least one kind of blast furnace gas, coke oven gas, and converter gas.

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