JP4231735B2 - Method and apparatus for separating and recovering carbon dioxide - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  In the present invention, carbon dioxide (hereinafter simply referred to as CO₂Also abbreviated. ) Separated and recoveredFixedMethod and apparatus. For details, use chemical absorption and CO₂When separating and collecting, CO₂CO supplied from (generation) source₂CO from contained gas₂Absorbing medium that has absorbed water can be recycled in one place to improve equipment efficiency,₂In a different location than the (source)Low gradeCO that makes it possible to use waste heat₂ TheSeparation and recoveryAnd immobilizeIt relates to a method and a device. Furthermore, large-scale CO₂At steelworks that have a source, low-grade (low-temperature) waste heat, which is considered difficult to recover even if heat is recovered as waste heat, is used.UseCO, such as by-product gas (unburned gas), its combustion exhaust gas or its reforming process gas₂Contains gasEt CO₂ TheSeparation and recoveryAnd immobilizeMethodAnd equipmentIt is about. Hereinafter, such an absorption medium is also referred to as a chemical absorption liquid, a carbon dioxide absorption medium, or an absorption liquid.
[0002]
[Prior art]
  In response to the global warming issue, it has been strongly promoted mainly by promoting energy conservation at the manufacturing and utilization stages, utilizing new energy such as solar, wind and biomass, and switching to low environmental impact fuels such as natural gas.
[0003]
  On the other hand, research to separate, recover, sequester and fix the global warming gas (carbon dioxide) that has been generated has also been promoted. For example, a method for separating and recovering carbon dioxide from combustion waste gas of a thermal power plant using a chemical absorption method has been proposed (see, for example, Non-Patent Document 1). It is said that a carbon separation and recovery rate of 90% can be achieved.
[0004]
[Non-Patent Document 1]
    Masataka Kiyohara, “CO from boiler exhaust gas for power generation₂"Recovery test", Energy and Resources, Japan Society of Energy and Resources, 1993, Vol. 14, No. 1, p. 91-97
[0005]
[Problems to be solved by the invention]
  However, when carbon dioxide is separated and recovered by the chemical absorption method from the combustion exhaust gas of such a thermal power plant (boiler exhaust gas for power generation), the concentration of carbon dioxide contained in the combustion exhaust gas of the thermal power plant is several to tens of vol%. The equipment used for the chemical absorption method was large. In addition, when carbon dioxide is separated and recovered by the chemical absorption method, thermal energy is a dominant factor in running cost. However, in a thermal power plant optimized for a single process of power generation, there is no waste heat that can be used for the chemical absorption method, and a new thermal energy generation facility or steam used for power generation is used. I had to take a method to reduce the power generation efficiency by using the.
[0006]
  On the other hand, there is no economic advantage (separate cost increase) when sequestering the separated and recovered carbon dioxide in the ground or in the ocean, and the domestic market is small and demanded even if it is used effectively for chemical raw materials. There is a structural problem that the economic traction does not work.
[0007]
  Therefore, an object of the present invention is to separate and collect carbon dioxide discharged from an ironworks, which is one of large-scale carbon dioxide generation sources, efficiently and inexpensively with a small-scale facility compared to a thermal power plant.FixedThe technology to do is provided.
[0008]
  Another object of the present invention is to generate carbon dioxide sources at different locations.ChemistryBy combining an absorption liquid regeneration heat source, carbon dioxide is separated and recovered from the carbon dioxide source efficiently and inexpensively.FixedThe technology to do is provided.
[0009]
[Means for Solving the Problems]
  Therefore, the present inventors have separated and recovered carbon dioxide discharged from a large-scale carbon dioxide generation source in order to achieve the above object.FixedAs a result of diligent research on the technology to produce, by-product gas (unburned gas) such as blast furnace gas generated at steelworks, which is a large-scale carbon dioxide generation source, The ratio (concentration) is as high as 20% to 30%. Therefore, chemical absorptionLawSeparation and recovery of carbon dioxide usingFixedIn this case, it was found that the equipment for separating and recovering the same amount of carbon dioxide can be remarkably reduced in size compared with a thermal power plant. In addition, the steelworks are made up of numerous processes such as blast furnaces, converters, sintering, coke ovens, heating furnaces, castings and rolling, and various improvements have already been made to save energy. It was thought that only low-grade thermal energy that could not be utilized was left, but this was useful for heating chemical absorption liquids, which is a dominant factor in operating costs.UseIt was also found that the running cost of the chemical absorption method can be greatly reduced. Furthermore, the above-mentioned by-product gas is used as a fuel gas in the iron making process. By extracting carbon dioxide in the middle of the process, the energy density of the gas is increased and the thermal efficiency of the subsequent process is improved. I also learned that I can. In addition, in the combustion exhaust gas after combusting and using by-product gas such as converter gas in the steelworks, CO is at a high ratio of over 30%.₂It has also been found that the facility for separating and recovering carbon dioxide can be further reduced in size. Based on these findings, the present invention has been completed.
[0010]
  Furthermore, the present inventors have developed a carbon dioxide by chemical absorption method.ofWhen analyzing the separation and recovery costs, the biggest cost factor isChemical absorption liquidIt has been concluded that this efficiency is effective in achieving the purpose of separating and recovering carbon dioxide efficiently and inexpensively.
[0011]
  That is, the present invention can be achieved by the method and apparatus for separating and recovering and fixing carbon dioxide described in the following (1) to (4).
[0012]
  (1) An apparatus that separates and recovers carbon dioxide from blast furnace gas and has an apparatus for separating and recovering carbon dioxide and an apparatus for fixing carbon dioxide,
  The device that separates and recovers carbon dioxide
    For transporting blast furnace gas from the blast furnace to the next process of the steel plantBlast furnace gasMainCarbon dioxide absorption equipment for absorbing carbon dioxide from the blast furnace gas supplied from
    A chemical absorption liquid regeneration facility for separating carbon dioxide from a chemical absorption liquid that has absorbed carbon dioxide using a heat source for chemical absorption liquid regeneration and regenerating the chemical absorption liquid;,
    Carbon dioxide absorption equipment to chemical absorption liquid regeneration equipmentWhatA delivery pipe for transporting the chemical absorbent that has absorbed carbon dioxide;
    Chemical absorption liquid regeneration equipment to carbon dioxide absorption equipmentWhatA return pipe for transporting the regenerated chemical absorbent,
  The device that immobilizes carbon dioxide
    Apparatus for separating and recovering carbon dioxide as described abovesoIt has equipment to fix the collected carbon dioxide in the ground or the sea,
  As a heat source for chemical absorption liquid regeneration, low-grade exhaust heat of 500 ° C or less generated at steelworks is used.
HighFurnace gasFrom the mainCarbon dioxide absorption equipmentThe length X of the pipe for supplying the blast furnace gas to the pipe, the length Y of the feed pipe for the chemical absorption liquid, and the length Z of the return pipe,Heat source for chemical absorption liquid regenerationAnd the length W of the pipe for supplying heat to the chemical absorbent regenerating facility from X <Y, X <Z, W <Y, and W <ZSatisfies the relational expressionDoAn apparatus for separating and recovering and immobilizing carbon dioxide.
[0013]
  (2)An apparatus for separating and recovering carbon dioxide from blast furnace gas, having an apparatus for separating and recovering carbon dioxide and an apparatus for fixing carbon dioxide,
The device that separates and recovers carbon dioxide
A carbon dioxide absorption facility for absorbing carbon dioxide from the blast furnace gas supplied from the blast furnace gas main for transporting the blast furnace gas from the blast furnace to the next process of the steel plant, with a chemical absorption liquid;
A chemical absorption liquid regeneration facility for separating carbon dioxide from the chemical absorption liquid that has absorbed carbon dioxide using a heat source for chemical absorption liquid regeneration and regenerating the chemical absorption liquid;
A delivery pipe for transporting the chemical absorption liquid that has absorbed carbon dioxide from the carbon dioxide absorption equipment to the chemical absorption liquid regeneration equipment;
A return pipe for transporting the chemical absorbent regenerated from the chemical absorbent regenerator to the carbon dioxide absorber,
The device that immobilizes carbon dioxide
It has equipment for fixing the carbon dioxide recovered by the device for separating and recovering carbon dioxide described above to the ground or the sea,
As a heat source for chemical absorption liquid regeneration, low-grade exhaust heat of 500 ° C or less generated at steelworks is used.
HighFurnace gasMainFor supplying blast furnace gas from CO2 to carbon dioxide absorption equipmentLength ofX and feed pipe for chemical absorption liquidLength ofY and return pipingLength ofZ and piping for supplying heat to the chemical absorption liquid regeneration facility from the heat source for chemical absorption liquid regenerationLength ofW satisfies at least one of a relational expression of 2X <(Y + Z) or a relational expression of (X + W) <(Y + Z).RujiEquipment for separating and recovering and fixing carbon oxides.
[0014]
  (3)For transporting blast furnace gas from the blast furnace to the next process of the steel plantBlast furnace gasMainAt a carbon dioxide absorption facility close toThe heightFurnace gasMainAfter absorbing carbon dioxide from the blast furnace gas supplied from
  Heating the chemical absorption liquid using a heat source for chemical absorption liquid regeneration, separating and recovering carbon dioxide in a chemical absorption liquid regeneration facility adjacent to the heat source for chemical absorption liquid regeneration,
  The recovered carbon dioxideImmobilizeA method for separating and recovering carbon dioxide from blast furnace gas as a carbon dioxide generation source, characterized by being fixed in the ground or in the sea by equipment,
  As a heat source for regenerating the chemical absorbent, low-grade exhaust heat of 500 ° C. or less generated at a steel mill is used,
HighFurnace gasFrom the mainCarbon dioxide absorption equipmentThe length X of the pipe for supplying blast furnace gas to the pipe, the length Y of the delivery pipe for transporting the chemical absorption liquid that absorbed carbon dioxide from the carbon dioxide absorption equipment to the chemical absorption liquid regeneration equipment, and the chemical absorption liquid A return pipe length Z for transporting the regenerated chemical absorbent from the regenerator to the carbon dioxide absorber;Heat source for chemical absorption liquid regenerationAnd the length W of the pipe for supplying heat to the chemical absorbent regenerating facility from X <Y, X <Z, W <Y, and W <ZSatisfies relational expressionDoA method for separating and recovering and immobilizing carbon dioxide characterized by the above.
[0015]
  (4)Carbon dioxide is absorbed from the blast furnace gas supplied from the blast furnace gas main in the carbon dioxide absorption facility adjacent to the blast furnace gas main for transporting the blast furnace gas from the blast furnace to the next process of the steel plant. After absorption
Heating the chemical absorption liquid using a heat source for chemical absorption liquid regeneration, separating and recovering carbon dioxide in a chemical absorption liquid regeneration facility adjacent to the heat source for chemical absorption liquid regeneration,
A method for separating and recovering carbon dioxide from a blast furnace gas of a carbon dioxide generation source, which is characterized in that it is fixed in the ground or in the sea by a facility for fixing the recovered carbon dioxide,
As a heat source for regenerating the chemical absorbent, low-grade exhaust heat of 500 ° C. or less generated at a steel mill is used,
HighFurnace gasMainFor supplying blast furnace gas from CO2 to carbon dioxide absorption equipmentLength ofX andCarbon dioxide was absorbed from the carbon dioxide absorption facility to the chemical absorption liquid regeneration facilityChemical absorption liquidFor transportDelivery pipingLength ofY andFor transport of regenerated chemical absorption liquid from chemical absorption liquid regeneration equipment to carbon dioxide absorption equipmentReturn pipingLength ofZ and piping for supplying heat to the chemical absorption liquid regeneration facility from the heat source for chemical absorption liquid regenerationLength ofW satisfies at least one of the relational expression of 2X <(Y + Z) or the relational expression of (X + W) <(Y + Z)DoIt is characterized byRujiA method of separating and recovering and fixing carbon oxides.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
  Hereinafter, the present invention will be described in detail.ExamplesEach requirement will be explained in detail.In additionIt goes without saying that it should not be restricted.
[0017]
  Main departureTomorrow,An apparatus for separating and recovering carbon dioxide from blast furnace gas, having an apparatus for separating and recovering carbon dioxide and an apparatus for fixing carbon dioxide,
The device that separates and recovers carbon dioxide
A carbon dioxide absorption facility for absorbing carbon dioxide from the blast furnace gas supplied from the blast furnace gas main for transporting the blast furnace gas from the blast furnace to the next process of the steel plant, with a chemical absorption liquid;
A chemical absorption liquid regeneration facility for separating carbon dioxide from the chemical absorption liquid that has absorbed carbon dioxide using a heat source for chemical absorption liquid regeneration and regenerating the chemical absorption liquid;
A delivery pipe for transporting the chemical absorption liquid that has absorbed carbon dioxide from the carbon dioxide absorption equipment to the chemical absorption liquid regeneration equipment;
A return pipe for transporting the chemical absorbent regenerated from the chemical absorbent regenerator to the carbon dioxide absorber,
The device that immobilizes carbon dioxide
It has equipment for fixing the carbon dioxide recovered by the device for separating and recovering carbon dioxide described above to the ground or the sea,
As a heat source for chemical absorption liquid regeneration,Utilizing low-grade exhaust heat of 500 ° C or less generated at steelworksAnd
The length X of the pipe for supplying blast furnace gas from the blast furnace gas main to the carbon dioxide absorption facility, the length Y of the feed pipe for the chemical absorption liquid, the length Z of the return pipe, and a heat source for regenerating the chemical absorption liquid Satisfies the relational expressions X <Y, X <Z, W <Y, and W <Z with the length W of the pipe for supplying heat to the chemical absorption liquid regeneration facility fromIt is characterized by doing.
[0018]
The present invention also provides a chemical absorption liquid from a blast furnace gas supplied from the blast furnace gas main in a carbon dioxide absorption facility adjacent to the blast furnace gas main for transporting the blast furnace gas from the blast furnace to the next process of the steel plant. After absorbing carbon dioxide using
Heating the chemical absorption liquid using a heat source for chemical absorption liquid regeneration, separating and recovering carbon dioxide in a chemical absorption liquid regeneration facility adjacent to the heat source for chemical absorption liquid regeneration,
A method for separating and recovering carbon dioxide from a blast furnace gas of a carbon dioxide generation source, which is characterized in that it is fixed in the ground or in the sea by a facility for fixing the recovered carbon dioxide,
As a heat source for regenerating the chemical absorbent, low-grade exhaust heat of 500 ° C. or less generated at a steel mill is used,
The length X of the pipe for supplying blast furnace gas from the blast furnace gas main to the carbon dioxide absorption facility, and the delivery pipe for transporting the chemical absorbent that absorbed carbon dioxide from the carbon dioxide absorption facility to the chemical absorbent regeneration facility Length Y, length Z of the return pipe for transporting the chemical absorbent regenerated from the chemical absorbent regeneration facility to the carbon dioxide absorber, and heat from the heat source for chemical absorbent regeneration to the chemical absorbent regeneration facility The length W of the pipe for supplying the gas satisfies the relational expressions X <Y, X <Z, W <Y, and W <Z.
[0019]
  (BookinventionofCarbon dioxideSeparation and recoveryEquipment to do andPlant to which the method can be applied)
  BookinventionofCarbon dioxideSeparation and recoveryEquipment to do andMethod (hereinafter, bookinventionSeparation and recoveryEquipment andAs a plant to which the method can be applied,FurnaceIt is not particularly limited as long as it is a steel mill that can generate low-grade exhaust heat of 500 ° C. or less.
[0020]
  (Raw material gas)
  Also bookinventionSeparation and recoveryEquipment andBy-product gas (unburned gas) generated at steelworks as raw material gas used in the methodUsing blast furnace gasAs long as the blast furnace integrated steel works are taken as an example, the blast furnace gas (BFG)Besides, Coke oven gas (COG), converter gas (LDG), COG, LDG, etc.Vice ofGas (process gas) produced during the process of reforming raw gas for the purpose of hydrogen production (process) is also included. These by-product gases may be used alone or in a mixed state in which two or more kinds are mixed. Also bookinventionSeparation and recoveryEquipment andIn the method, the combustion exhaust gas of the byproduct gas may be used as a raw material gas for carbon dioxide separation and recovery. When these raw material gases (by-product gas generated at the steelworks or combustion exhaust gas thereof) can be used as high-quality exhaust heat, those after use are used. This is because the temperature condition at the time of carbon dioxide absorption by the chemical absorption method may be around room temperature. Each of these source gases may be used alone for carbon dioxide separation and recovery, or two or more may be mixed and used for carbon dioxide separation and recovery. The mixed form of two or more kinds includes a mixed form of by-product gases, a mixed form of by-product gas combustion exhaust gas, and a mixed form of by-product gas combustion exhaust gas and by-product gas. .
[0021]
  Among these source gases, BFG has a high carbon dioxide ratio of 20 to 20%. In addition, hydrogen as a fuel component contains several percent and carbon monoxide contains 20 to 20%. Next, COG contains abundant hydrogen and methane suitable as fuel gas, and the concentration of carbon dioxide in the exhaust gas after combustion (also referred to as combustion exhaust gas) is more than 20%. On the other hand, LDG contains about 70% of carbon monoxide together with tens of percent of carbon dioxide, and the concentration of carbon dioxide in the exhaust gas after combustion (combustion exhaust gas) is as high as 30%. Yes. Therefore, as the source gasThe, BFG has a higher carbon dioxide ratio than carbon dioxide in thermal power plantsIs used. Besides BFGBFG combustion exhaust gas, COG combustion exhaust gas, LDG combustion exhaust gas, and a mixed gas of these gases and other gases may be used. Further, a gas produced in the process of reforming COG and LDG, which will be described later, and producing hydrogen can also be suitably used. Specifically, the carbon dioxide ratio (concentration) in the raw material gas generated from these steelworks is 15% by volume or more, preferably 18% by volume or more, more preferably 20% by volume or more, and further preferably 22% by volume or more. Especially preferably, it is 25 volume% or more. When carbon dioxide is separated and recovered from these gases with high carbon dioxide ratio by means such as chemical absorption, low-concentration combustion exhaust gas from thermal power plants (about 8% at natural gas thermal power plants, at coal-fired power plants) This is because the scale of the facility can be significantly reduced compared with the case of using about 12% as a raw material gas (for example, compared with the low-concentration combustion exhaust gas of a coal-fired power plant, When BFG is used as a raw material gas, it can be reduced by about 30% as the equipment cost of the chemical absorption method for separating and recovering carbon dioxide.)
[0022]
  (CO2 separation and recovery process)
  BookinventionSeparation and recoveryEquipment andIn the method, carbon dioxide is separated and recovered from a raw material gas by a chemical absorption method. This requires a large-scale facility capacity of 1 million tons / year when carbon dioxide is separated and recovered from a steelworks that is a large-scale carbon dioxide emission source as a measure against global warming. In this case, the most widely developed and widely used method for separating and recovering carbon dioxide is the chemical absorption method. Hereinafter, the process principle of the chemical absorption method will be described with reference to the drawings. FIG. 1 is a principle diagram of a process for separating and recovering carbon dioxide from a source gas containing carbon dioxide by a chemical absorption method.
[0023]
  As shown in FIG. 1, the chemical absorption method is a raw material gas 3 containing carbon dioxide and a carbon dioxide absorption medium in a reaction tower called an absorption tower 1 which is a carbon dioxide absorption facility using a chemical absorbent such as amines. The chemical absorption liquid 5 is brought into contact at around 50 ° C. and carbon dioxide is absorbed by the chemical absorption liquid.ChemistryIt is sent through a delivery pipe 6 to a regeneration tower 7 which is an absorption liquid regeneration facility, and reaches around 120 ° CChemistryHeating is performed using a heating medium 9 that is a heat source for absorbing liquid regeneration, carbon dioxide is separated and recovered from the chemical absorbing liquid in the regeneration tower 7, and the regenerated chemical absorbing liquid is returned to the absorbing tower 1 through the return pipe 8. Thus, the chemical absorption liquid is circulated between the absorption tower 1 and the regeneration tower 7 and recycled.
[0024]
  As the chemical absorption liquid, conventionally known ones can be used as appropriate, for example, an aqueous solution containing amines can be used, and there is no particular limitation.
[0025]
  BookinventionSeparation and recoveryEquipment andIn the method, the thermal energy required for heating in the regeneration tower is a dominant factor in the operating cost of the present method. So bookinventionSeparation and recoveryEquipment andIn the wayChemistryAs a heat source for absorbing liquid regeneration, low-grade exhaust heat of 500 ° C. or less, preferably 400 ° C. or less generated at steelworks is used.UseIs. Ie bookinventionSeparation and recoveryEquipment andThe method uses low-grade heat energy that is difficult to use in the steelmaking process (of the low-grade heat energy, the highest possible one is used).UseIs desirable. )UseThus, it is not necessary to provide a thermal energy generation facility as in a thermal power plant to generate heating steam (heating medium 9) or to use steam used for power generation. Therefore, the carbon dioxide separation and recovery cost by the chemical absorption method can be greatly reduced. In addition, since the carbon dioxide concentration of the raw material gas is high as described above, not only the equipment can be made compact, but also the usage amount of utilities (electric power and water) necessary for the equipment can be reduced, thereby further reducing the operating cost. Can do.
[0026]
  Here, it is useful for the process of separating carbon dioxide.UseThe low-grade exhaust heat generated at the steelworks is set to 500 ° C or less. Exhaust heat exceeding 500 ° C is used as high-quality exhaust heat at the current steelworks. It is necessary to install a new thermal energy generation facility to reduce the production efficiency similar to using (converting) the steam for power generation at the power plant, or to separate the carbon dioxide at low cost. It becomes difficult to achieve the purpose of collection. However,The present inventionCombined with high-grade exhaust heat that slightly exceeds 500 ° C and fuel combustion heat to the extent that it does not affect the steelmaking process sideUseIfIncluding. Ie bookinventionIn this separation and recovery method, only the low-grade exhaust heat of 500 ° C. or less generated at the steelworks is used for the process of separating carbon dioxide.UseIt should not be construed narrowly unless it is obtained, and within a range not departing from the object of the present invention, high-grade exhaust heat exceeding 500 ° C. and use of combustion heat of fuel may be possible.
[0027]
  Examples of low-grade exhaust heat of 500 ° C. or less generated at steelworks include exhaust heat from a sintered product cooler (about 350 ° C.), sintered main exhaust gas (about 280 ° C.), and hot stove exhaust gas (about 230 ° C.). ), The main exhaust gas (about 180 ° C), and the wastewater used for granulating blast furnace slag (about 90 ° C). It should not be restricted. In other words, at present steelworks (steel production plants), high-purity hydrogen is recovered at the same time by using a steam reformer combined with oxygen combustion for steam reforming from COG or LDG as a by-product gas to hydrogen-rich gas. The exhaust gas after recovery is being used for converters in steel plants, and so on, making it more sophisticated and complex. Therefore, this is also true for low-grade exhaust heat generated through equipment installed in steelworks (steelworks or processes).inventionThis is included in the low-grade exhaust heat of the separation and recovery method. Preferably, low-grade exhaust heat below the exhaust heat temperature from the sintered product cooler is used.UseIs desirable. Excess heat from the sintered product cooler (approx. 350 ° C) depends on the structure of the steel plant, but is already effectively used as a high-quality heat source in steel plants where the current energy recovery technology has advanced greatly. It is because it has been. The specific temperature (numerical value) was not specified because of the process of separating and recovering carbon dioxide by the chemical absorption method using the set conditions in the sintered product cooler and the exhaust heat from the sintered product cooler. The process of separating and recovering carbon dioxide by the chemical absorption method according to changes in the distance to the equipment) and the outside temperature.To useThis is because the temperature at the time of serving also varies slightly. More preferably, exhaust heat at a temperature as high as possible is higher than the heating temperature of the chemical absorption liquid in the regeneration tower (around 120 ° C.).UseIt is desirable to heat with steam. This is because the larger the temperature difference between the chemical absorption liquid and the exhaust heat, the smaller the equipment required for heat exchange can be achieved.₂This is because the cost of separating and recovering can be reduced.
[0028]
  Such low-grade exhaust heat isUse"What isThe low-grade exhaust heat is directly used as a heating medium (heat energy) used to heat the regeneration tower.Other than whenThe low-grade exhaust heat is used to heat and hold a heating medium (for example, steam) at a predetermined temperature.This includes cases where it is used.. The former is desirable in terms of simple apparatus configuration and low heat loss, and the latter is desirable in terms of ease of control of maintaining the chemical absorption liquid in the regeneration tower at a constant temperature. In addition, when low-grade exhaust heat is passed through the heating medium, the heat transfer coefficient does not decrease due to corrosion in the pipe or accumulation of impurities due to corrosive components and impurities contained in the low-grade exhaust heat (drainage and exhaust gas). It is desirable to remove them.
[0029]
  Also bookinventionSeparation and recoveryEquipment andIn this method, the low-grade exhaust heat (thermal energy) is used alone (as a single exhaust heat).UseOr two or more low-grade exhaust heatUseMay be. As an embodiment to be used in combination, when the heating medium is heated to a predetermined temperature, two or more kinds of low-grade exhaust heat may be boosted up from a low temperature. At this time, if there is insufficient heat energy at the end, the fuel may be used for combustion. Ie bookinventionHow to separate and collectEquipment andIn this method, only low-grade exhaust heat is used for the process of separating and recovering carbon dioxide by chemical absorption.UseIn addition to being self-consumed in the steel plant, it is also possible to use part of the fuel gas sold for city gas etc. as auxiliary fuel. This wayOf the separation and recovery method and method of the present inventionEmbodiments will be briefly described with reference to the drawings. 2 to 4 shown below, the same reference numerals are assigned to the same devices and the like as those in FIG. 1 and FIGS.
[0030]
  First of all, FIG. 2 is necessary for the regeneration of the chemical absorbent.Full of heat(Or part)InOccurs in steelworksLow gradeIt is drawing which represented typically the process for isolate | separating and collect | recovering a carbon dioxide by the chemical absorption method from the raw material gas (FIG. 2 shows the example of by-product gas) which utilizes exhaust heat.
[0031]
  First, in the embodiment shown in FIG. 2, the chemical absorption liquid 5 such as amines is used, and the by-product gas 3 of the raw material gas containing carbon dioxide and the chemical absorption liquid 5 are made near normal temperature (for example, around 50 ° C.) in the absorption tower 1. ), Carbon dioxide is absorbed into the chemical absorption liquid, and then the liquid is sent to the regeneration tower 7 and heated to a predetermined regeneration temperature (for example, around 120 ° C.) using the heating medium 9. Necessary for regeneration of chemical absorption liquidAll of the heat, Low-grade exhaust heat of 500 ° C or less (for example, exhaust heat from a sintered product cooler) generated at steelworksUseIn this example, carbon dioxide 11 is separated and recovered from the chemical absorption liquid. The low-grade exhaust heat is used to heat the heating medium 9 such as heating steam as described above.UseIt may be used directly as the heating medium 9,FormThere is no particular limitation on the state.
[0032]
  The by-product gas 13 after carbon dioxide separation after the absorption column 1 has absorbed the carbon dioxide in the chemical absorption liquid 5 is returned to the by-product gas pipe 15,SteelUsed as fuel gas in the process. Further, the chemical absorption liquid heated in the regeneration tower 7 and extracted with carbon dioxide isRegenerated chemical absorbent (Regenerative absorbent)5 'is returned to the absorption tower 1.
[0033]
  Moreover, in this embodiment, it is necessary for the regeneration of the chemical absorbent.All of the heatThe low-grade exhaust heat of 500 ° C or less generated at steelworksUseAn example is shown, but it is necessary to regenerate the chemical absorbent.FeverpartLow-grade exhaust heat of 500 ℃ or lessAn example of use will be described with reference to FIG.
[0034]
  Next, in the embodiment shown in FIG. 3, the chemical absorption liquid 5 such as amines is used, and the by-product gas 3 of the raw material gas containing carbon dioxide and the chemical absorption liquid 5 are made near the normal temperature (for example, 50 ° C.). Before and after absorbing carbon dioxide in the chemical absorption liquid, the liquid is sent to the regeneration tower 7 and heated to a predetermined regeneration temperature (for example, around 120 ° C.) using the heating medium 9. Depending on the characteristics of the chemical absorption liquid, appropriate low-grade exhaust heat of 500 ° C. or less generated at the ironworks for the regeneration of the chemical absorption liquid is divided into multiple stages. In FIG. Boosting up, low-quality exhaust heat at the lowest temperature (for example, wastewater used for granulating blast furnace slag (about 90 ° C)), then low-quality exhaust heat at the lowest temperature (for example, Sintering main exhaust gas (about 280 ℃) etc., the highest temperature and low quality exhaust heat (for example, , Interest waste heat from the sintered product cooler (about 350 ℃), etc.)UseIn this example, carbon dioxide 11 is separated and recovered from the chemical absorption liquid. Note that the above three types of low-grade exhaust heat are sequentially used to heat the heating medium 9 such as heating steam as described above.UseIt may be used directly as the heating medium 9 in order.FormThere is no particular limitation on the state.
[0035]
  The by-product gas 13 after carbon dioxide separation after the absorption column 1 has absorbed the carbon dioxide in the chemical absorption liquid 5 is returned to the by-product gas pipe 15,SteelUsed as fuel gas in the process. Further, 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 '.
[0036]
  In the present embodiment, “according to the characteristics of the chemical absorbent” means that the amount of heat necessary for regeneration of the chemical absorbent is greatly different depending on the characteristics of the chemical absorbent used, and the operating temperature range is restricted. This is because there is a chemical absorption liquid, and this point needs to be fully considered when combining exhaust heat. In addition, it is desirable to consider this point similarly in other embodiments.
[0037]
  Furthermore, Fig. 4 shows the exhaust heat generated at the steelworks for the regeneration of the chemical absorbent.UseAnd work
Using the steam for the plant, carbon dioxide is separated from the raw material gas generated at the steelworks by the chemical absorption method.
It is drawing which represented typically the process for collecting.
[0038]
  Further, in the embodiment shown in FIG. 4, the chemical absorption liquid 5 such as amines is used, and the by-product gas 3 of the raw material gas containing carbon dioxide and the chemical absorption liquid 5 are made near normal temperature (for example, around 50 ° C.) in the absorption tower 1. After the carbon dioxide is absorbed in the chemical absorption liquid, the liquid is sent to the regeneration tower 7 and is heated to a predetermined regeneration temperature (for example, around 120 ° C.) using the heating medium 9 for chemical absorption. In order to regenerate the liquid, use low-grade exhaust heat of 500 ° C or less (for example, exhaust heat from a sintered product cooler) generated at steelworks as much as possible.UseIn addition, an example of separating and recovering the carbon dioxide 11 from the chemical absorption liquid using a factory steam or the like for the shortage is shown. In this embodiment, low-grade exhaust heat of 500 ° C. or less generated at steelworks as much as possibleUseBy doing so, it is possible to reduce the required amount of factory steam. For convenience, FIG. 4 shows an example in which exhaust heat from a sintered product cooler or the like is used in one stage for low-grade exhaust heat of 500 ° C. or less generated at a steel mill, but as shown in FIG. Useful for multiple stagesUseNeedless to say. The low-grade exhaust heat is used to heat the heating medium 9 such as heating steam as described above.UseIt may be used directly as the heating medium 9,FormThere is no particular limitation on the state. Also, factory steam, etc. can be directly heated steam (heating medium 9)UseOr to heat the heating medium 9UseMay be.
[0039]
  The by-product gas 13 after carbon dioxide separation after the absorption column 1 has absorbed the carbon dioxide in the chemical absorption liquid 5 is returned to the by-product gas pipe 15,SteelUsed as fuel gas in the process. Further, 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 '.
[0040]
  Also, in this embodiment, “as much as possible” is used as shown in FIG.AvailableThis is because there may be a case where the amount of heat necessary for the regeneration of the chemical absorption liquid is insufficient in addition to using all of the low-grade exhaust heat of 500 ° C. or less generated at a competent steelworks. The reason why factory steam is used in such a case is that the use (diversion) of factory steam, which is currently widely used in steelworks, is most convenient and inexpensive. However, the present invention does not exclude the use of heat sources other than such factory steam, such as exhaust heat, and other exhaust heat, etc. can be used as long as it does not impair the purpose of the present invention. it can.
[0041]
  Further, in the present invention, low-grade exhaust heat of 500 ° C. or less generated at steelworks is used for the process of separating and recovering carbon dioxide by the chemical absorption method.UseAny thermal energy required for heating in the regeneration tower described above.UseYou should not be limited to what you do. In other words, the heat energy required for heating in the regeneration tower, which is the dominant factor in operating costs,UseHowever, the chemical absorption method, which is the most widely developed and popularized carbon dioxide separation and recovery method, is not limited to the process principle (apparatus configuration) as shown in FIG. Therefore, it is not as much as the heat energy required for heating in the regeneration tower, but in the process actually used, heat exchange and heating may be required. FeverUseIt can be said.
[0042]
  In addition, the separation and collection of this embodimentEquipment andAs a process for separating and recovering carbon dioxide using a chemical absorption method, which can be applied by the above method, the above-mentioned “low-grade exhaust heat of 500 ° C. or less generated at steelworks is used.UseRequirements, And "For the transport of chemical absorption liquid that absorbed carbon dioxide from the carbon dioxide absorption equipment to the chemical absorption liquid regeneration equipment, the length X of the pipe for supplying blast furnace gas from the blast furnace gas main to the carbon dioxide absorption equipment The length Y of the feed pipe, the length Z of the return pipe for transporting the chemical absorbent regenerated from the chemical absorbent regeneration facility to the carbon dioxide absorber, and the chemical absorbent re- The length W of the pipe for supplying heat from the raw heat source to the chemical absorption liquid regeneration facility satisfies the relational expressions X <Y, X <Z, W <Y, and W <Z. " RequirementAs long as the above is satisfied, there is no particular limitation. Therefore, after absorbing carbon dioxide with the chemical absorption liquid from the raw material gas containing carbon dioxide (by-product gas generated at steelworks and its combustion exhaust gas), which is another requirement, the chemical absorption liquid is heated to separate the carbon dioxide. Carbon dioxide separation and recovery technology using chemical absorption methods, such as the type, concentration and volume of chemical absorption liquid used in the process, apparatus configuration of the process, conditions such as temperature and pressure in the process, various control methods, etc. It has already been known and many improvements have been made, and it goes without saying that these improved techniques can be applied to the separation and recovery method of the present embodiment. And detailed descriptions are omitted here.
[0043]
  (How to use by-product gas after carbon dioxide extraction)
  Although the above-mentioned steelworks by-product gas has a difference in calorific value, all of them have already been used as heat as fuel. Among these, when carbon dioxide is first extracted from BFG and reused as a process gas, there are utilization methods such as 1) fuel for a gas turbine, 2) reinjection into a blast furnace, and 3) utilization in a semi-reduced steel manufacturing process.
[0044]
  In the usage method of 1) above, the amount of heat of BFG is 750 → 1000 kcal / Nm.³It is no longer necessary to add auxiliary fuel such as light oil. Further, in the utilization method of 2) above, by re-injecting into the blast furnace, it can contribute to the reduction reaction of iron that reaches chemical equilibrium by the amount of carbon dioxide, and the amount of coke that is a reducing agent is used. Can also be reduced. In addition, in the above method 3), the amount of natural gas or coal used can be reduced by using this reducing gas in a process in which natural gas or coal is used for the preliminary reduction of iron ore before the blast furnace. Can be reduced. As described above, when carbon dioxide is extracted and reused as a process gas, it is possible to express useful effects as compared with the current use of heat. These functions and effects are excellent in that they can be used in a useful manner that cannot be obtained from exhaust gas that has been extracted from the combustion exhaust gas obtained by air combustion of conventional fossil fuels and that has been diffused into the atmosphere.
[0045]
  In addition, when hydrogen production is performed by reforming COG or LDG, it is possible to reduce hydrogen production costs by extracting unnecessary carbon dioxide during the production. In the case where COG or LDG is used as heat in the site, the same effects as in the case where carbon dioxide is extracted from the BFG and reused as process gas can be obtained.
[0046]
  (How to use separated and recovered carbon dioxide; Method and apparatus for immobilization)
  The separated and recovered carbon dioxide has been studied mainly by the Global Environmental Industrial Technology Research Organization to store it in the ground or underwater such as aquifers and depleted natural gas fields for the purpose of mass immobilization. In addition to this, use in EOR (Forced Oil Recovery Method) and ECBM (Forced Recovery Method of Coal-Embedded Methane Gas) is beginning to progress mainly overseas. It is also possible to inject and immobilize carbon dioxide for forced recovery of natural gas even in water-soluble natural gas fields.
[0047]
  Among these, when storing in the ground or the sea such as aquifers and depleted natural gas fields for the purpose of mass fixation, the carbon dioxide is worthless and the recovery cost is as low as possible. Is desirable. In this respect, 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.
[0048]
  On the other hand, although the amount is about 10,000 t / year per steelworks, carbon dioxide is used for bottom blowing tuyeres at steelworks converters, and what is currently purchased from the market is separated. Carbon dioxide emissions can be reduced by using the collected carbon dioxide within the station.
[0049]
  Main departureTomorrowCarbon dioxide from a carbon dioxide sourceTheSeparation and recoveryAnd immobilizeIt relates to a method and a device.
[0050]
  Of these, carbon dioxideTheSeparation and recoveryAnd immobilizeThe deviceBlast furnace gas having a device for separating and recovering carbon dioxide and a device for fixing carbon dioxideSeparation and recovery of carbon dioxide fromFixedA device that performs
  The device that separates and recovers carbon dioxide
    Blast furnace supplied from the blast furnace gas main for transporting blast furnace gas from the blast furnace to the next process of the steel plantFrom gasWith chemical absorbentCarbon dioxide absorption equipment for absorbing carbon dioxide,
    Absorbed carbon dioxideChemical absorption liquidFromChemical absorption liquidUse a heat source for regeneration to separate carbon dioxideChemical absorption liquidFor playingChemical absorption liquidRegeneration equipment,
    Chemical absorption liquid that absorbed carbon dioxide from carbon dioxide absorption equipment to chemical absorption liquid regeneration equipmentWith delivery piping for transportation,
    For transport of regenerated chemical absorption liquid from chemical absorption liquid regeneration equipment to carbon dioxide absorption equipmentWith return pipingHave
  The device that immobilizes carbon dioxide
    It has equipment for fixing the carbon dioxide recovered by the device for separating and recovering carbon dioxide described above to the ground or the sea,
  As a heat source for chemical absorption liquid regeneration, low-grade exhaust heat of 500 ° C or less generated at steelworks is used.
  The length X of the pipe for supplying blast furnace gas from the blast furnace gas main to the carbon dioxide absorption facility, the length Y of the feed pipe for the chemical absorption liquid, the length Z of the return pipe, and a heat source for regenerating the chemical absorption liquid And the length W of the pipe for supplying heat to the chemical absorption liquid regeneration equipment satisfy the relational expressions X <Y, X <Z, W <Y, and W <Z.It is characterized by this.
[0051]
  Carbon dioxideTheSeparation and recoveryAnd immobilizeThe method isBlast furnace gas main for transporting blast furnace gas from the blast furnace to the next process of the steel plantThe carbon dioxide absorption facility close toBlast furnace gas mainSupplied fromBlast furnaceFrom gas, Chemical absorption liquidAfter absorbing carbon dioxide using
  Chemical absorption liquidUtilizing a heat source for regenerationChemical absorption liquidHeatedChemical absorption liquid in the vicinity of heat source for chemical absorption liquid regenerationSeparation of carbon dioxide at the regeneration facilityRecovered,
A method for separating and recovering carbon dioxide from a blast furnace gas of a carbon dioxide generation source, which is characterized in that it is fixed in the ground or in the sea by a facility for fixing the recovered carbon dioxide,
As a heat source for regenerating the chemical absorbent, low-grade exhaust heat of 500 ° C. or less generated at a steel mill is used,
The length X of the pipe for supplying blast furnace gas from the blast furnace gas main to the carbon dioxide absorption facility, and the delivery pipe for transporting the chemical absorbent that absorbed carbon dioxide from the carbon dioxide absorption facility to the chemical absorbent regeneration facility Length Y, length Z of the return pipe for transporting the chemical absorbent regenerated from the chemical absorbent regeneration facility to the carbon dioxide absorber, and heat from the heat source for chemical absorbent regeneration to the chemical absorbent regeneration facility The length W of the pipe for supplying the gas satisfies the relational expressions X <Y, X <Z, W <Y, and W <Z.It is characterized by this.
[0052]
  theseofIn the separation and recovery method and apparatus, the source of carbon dioxide at different locationsChemistryAbsorption liquid regenerationForBy combining heat sources, carbon dioxide can be separated and recovered efficiently and inexpensively. For example,To the blast furnace gas main for transporting blast furnace gas from the blast furnace in the steel plant to the next process of the steel plant, and further to the steel plantAdjacent thermal power plants (carbon dioxide sources) and steelworksLow grade below 500 ℃Waste heat source (ChemistryAbsorption liquid regenerationForIn combination with a heat source, it is possible to separate carbon dioxide at a lower cost than before.The present inventionThenExplained earlierChemical absorption method can be used. otherAlthough a method for separating and recovering carbon dioxide that requires heat may be used, since it is preferably a chemical absorption method, the chemical absorption method will be mainly described below.
[0053]
  Hereafter, this drawing is used with reference to the drawings.inventionHowever, the present invention is not limited to these. Figures 5-9 show carbon dioxide generation sources at different locations.ChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources. In these drawings, the same reference numerals are given to the constituent elements of the same devices and the like, and the description thereof may be omitted in FIG.
[0054]
  As shown in FIG. 5, the CO of this embodiment₂CO from the source₂The apparatus 50 for separating and recovering CO₂CO supplied from the source 53 through piping₂From contained gasChemical absorption liquid57 to CO₂To absorb CO₂Absorption equipment 55 and CO₂AbsorbedChemical absorption liquidFrom 57Chemical absorption liquidCO using the heat source 63 for regeneration₂IsolateChemical absorption liquidFor playingChemical absorption liquidRegeneration equipment 61 and CO₂CO as a transport medium₂It circulates between the absorption equipment 55 and the chemical absorption liquid regeneration equipment 61.Chemical absorption liquid57,Chemical absorption liquid57, a delivery pipe 59 for transportation and a return pipe 65 are provided.₂Absorption equipment 55 is CO₂Installed close to the source 53, andChemical absorption liquidRegeneration equipment 61 is CO₂It is installed at a location different from the generation source 53.
[0055]
  Therefore, the CO of this embodiment using the apparatus 50 is used.₂CO from the source₂The method of separating and recovering CO₂Generation source53CO close to₂The CO in the absorption equipment 55₂CO supplied from the source 53₂From the contained gas, CO₂CO as a transport medium₂With absorption equipment 55ChemistryCirculates between absorption liquid regeneration equipment 61Chemical absorption liquid57 using CO₂After absorbingChemical absorption liquidAt delivery pipe 59 for transportation of 57ChemistrySent to the absorbent regeneration facility 61,ChemistryThe heat source 63 for absorbing liquid regeneration is used toChemical absorption liquidHeat 57 and CO₂Generation source53Different placeChemistryCO is absorbed in the absorbent regeneration facility 61₂To separateChemical absorption liquidCO in return pipe 65 for transportation of 57₂It is made to circulate by returning to the absorption equipment 55.
[0056]
  (BookinventionPlants that can be separated and recovered)
  BookinventionAs a plant to which the separation and recovery method and apparatus can be applied, large-scale CO₂Generation sourceBlast furnace gas main for transporting blast furnace gas from the blast furnace to the next process of the steel plantSteelworks withOther than that,, Thermal power plant, cement plant, etc., but should not be limited to these. BookinventionThenFirstLarge-scale CO other than the explained steelworks₂It can also be applied to a plant having a source. For example, carbon dioxide sources at different locations (eg, thermal powerPlace)WhenChemistryAbsorption liquid regenerationForIt can be provided efficiently and inexpensively by combining heat sources (exhaust heat generated at other plants adjacent to the thermal power plant).
[0057]
  (Carbon dioxide source)
  BookinventionAs a carbon dioxide generation source inFirstAs explained above,SteelThis includes equipment that generates carbon dioxide in the plant and piping that transports carbon dioxide-containing gas from the equipment to the next process. Moreover, when discharging | emitting without transporting to the next process, this discharge equipment (a chimney etc.) shall also be contained in a carbon dioxide generation source. As an example of equipment for generating carbon dioxide, for example, an integrated blast furnace steel works,In addition to theCoke ovens, converters, and the like are applicable, and cement factories include, for example, cement kilns, but are not limited thereto. In addition, for example, blast furnace gas (BFG) piping, for example, blast furnace integrated steel worksIn addition to theCoke oven gas (COG) piping, converter gas (LDG) piping, and the like are applicable, but should not be limited to these.
[0058]
  (Carbon dioxide-containing gas (raw gas))
  Also bookinventionThe carbon dioxide-containing gas mentioned in is a carbon dioxide-containing gas generated from a carbon dioxide source.Made of blast furnace gasFor example, in the case of the above-mentioned steelworks, depending on the configuration, if an example of an integrated blast furnace steelworks is taken as an example, blast furnace gas (BFG)BesidesIn addition to by-product gas (unburned gas) such as coke oven gas (COG) and converter gas (LDG), the above-mentioned by-product gas such as COG and LDG is reformed for the purpose of hydrogen production (process) Gas produced in the process (process gas) is also included. Also bookinventionThen, it is good also considering the combustion exhaust gas of the said byproduct gas as a carbon dioxide containing gas (raw material gas). Further, for example, a suspension preheater outlet gas and an electric dust collector outlet gas are applicable at a cement manufacturing plant, and a combustion exhaust gas is applicable at a thermal power plant. However, the present invention should not be limited to these.
[0059]
  When these raw material gases (by-product gas or combustion exhaust gas generated from a carbon dioxide generation source) can be used as high-quality exhaust heat, it is desirable to use those after use. This is because the temperature condition at the time of carbon dioxide absorption may be around room temperature. Each of these source gases may be used alone for carbon dioxide separation and recovery, or two or more of them may be mixed. The mixed form of two or more kinds includes a mixed form of by-product gases, a mixed form of by-product gas combustion exhaust gas, and a mixed form of by-product gas combustion exhaust gas and by-product gas. . Ie bookinventionThen, a plurality of carbon dioxide absorption facilities can be provided close to a plurality of carbon dioxide generation sources, and a plurality of source gases can be handled.
[0060]
  Of these source gases, BFG, COG, LDG CO₂Concentration etc.FirstSince it is as explained, explanation here is omitted. In addition, CO of suspension pre-heater outlet gas generated at the cement factory₂The concentration is about 14% by volume, and the CO gas in the electric dust collector outlet gas.₂The concentration is about 9% by volume. Furthermore, the CO of combustion exhaust gas generated at thermal power plants₂The concentration is from several to a dozen volume%. BookinventionThen, it can utilize suitably also with respect to any of these source gases. As source gasTheA source gas with a high carbon dioxide concentration is desirable, and BFGIs used. Besides BFGIt can be said that BFG combustion exhaust gas, COG combustion exhaust gas, LDG combustion exhaust gas, and a mixed gas of these gases and other gases may be used. FurtherTo CA gas produced in the process of reforming OG and LDG to produce hydrogen can also be used suitably. When carbon dioxide is separated and recovered from these high-carbon dioxide source gases by means such as chemical absorption,FirstThis is because the same effect as described above can be obtained.
[0061]
  the aboveChemical absorption liquidIsFirstThe same chemical absorbing solution as described can be used, and is not particularly limited.
[0062]
  In addition, as a carbon dioxide absorption facility for absorbing carbon dioxide,FirstAlthough the thing similar to the absorption tower demonstrated can be used, it should not be restrict | limited in particular to these.
[0063]
  Also absorbed carbon dioxideChemical absorption liquidFromChemical absorption liquidUse a heat source for regeneration to separate carbon dioxideChemical absorption liquidFor playingChemical absorption liquidAs regeneration facilities,FirstAlthough the thing similar to the demonstrated regeneration tower | column can be used, it should not be restrict | limited in particular to these.
[0064]
  Furthermore, the delivery pipe and the return pipe are connected with carbon dioxide absorption equipment.Chemical absorption liquidCirculates between recycling facilitiesChemical absorption liquidIt is installed between the two for transportation.In detail, the delivery pipe for transporting the chemical absorption liquid that absorbed carbon dioxide from the carbon dioxide absorption facility to the chemical absorption liquid regeneration facility, and the transportation of the chemical absorption liquid regenerated from the chemical absorption liquid regeneration facility to the carbon dioxide absorption facility. A return pipe is installed.
[0065]
  Furthermore,Chemical absorption liquidIt is desirable to use process exhaust heat as a heat source for regeneration. Specifically, waste heat generated in the steelmaking process and waste heat generated in the cement manufacturing process.500 ° C or lessGoodIt is preferably a low-grade exhaust heat of 400 ° C. or lower, but should not be limited to these. Of these, regarding the waste heat generated in the steelmaking process,FirstSince it is the same as that described, description thereof is omitted here. Examples of exhaust heat generated in the cement manufacturing process include exhaust gas from a suspension preheater (about 380 ° C.), clinker cooler exhaust gas (about 350 ° C.), and exhaust gas from an electric dust collector (about 200 ° C.). It should not be limited to these. Also bookinventionsoIs,Chemical absorption liquidAs a heat source for regenerationBurningPart of the heat of combustionUseIn this case, it is included in the technical scope of the present invention.
[0066]
  Therefore,Chemical absorption liquidExamples of the heat source for regeneration include a sintered product cooler, a hot stove, a blast furnace granulated slag cooling device, a sintering furnace, and the like in the iron making process (see specific examples 1 to 5 described later), and cement production. Processes include suspension preheaters, clinker coolers, electrostatic precipitators, etc., but should not be limited to these.
[0067]
  Ie bookinventionThen, as shown in FIG.ChemistryIt is desirable to use the process waste heat 63a as a heat source (part or all) for regenerating the absorbent. this is,FirstAs explained, low-grade thermal energy that is difficult to use in steelworks and cement plants (of these low-grade thermal energy, use as high a temperature as possible)UseIs desirable. )UseThis is because the carbon dioxide separation and recovery costs can be greatly reduced. Also,ChemistryThe reason why low-grade exhaust heat of 500 ° C. or lower is desirable as a heat source for absorbing liquid regeneration is thatFirstFor the same reason as explained.
[0068]
  Also bookinventionThenChemistryAs a heat source for absorbing medium regeneration, one heat source is used alone.UseOr you can use two or more heat sources togetherUseMay be. As an embodiment to be used in combination, when heating the heating medium to a predetermined temperature, for example, two or more types of exhaust heat may be boosted up from a low temperature. At this time, if there is insufficient thermal energy at the end, the fuel may be used for combustion. Ie bookinventionTherefore, it is not always useful for the process of separating and recovering carbon dioxide by chemical absorption method using only the waste heat of the processUseFor example, in addition to being self-consumed in an iron manufacturing plant, it is possible to use part of the fuel gas sold for city gas as auxiliary fuel. Examples of these areAhead2-4, the description thereof is omitted here.
[0069]
  Then bookinventionThen, the carbon dioxide absorption facility is installed close to the carbon dioxide generation source,Chemical absorption liquidThe regeneration facility is installed at a location different from the carbon dioxide generation source. In the present invention,carbon dioxideSince a chemical absorption liquid is used as an absorption medium, even if the piping distance becomes long, theChemical absorption liquidThe motive power for transmitting the gas may be overwhelmingly less than that of the source gas (gas). On the other hand, when the carbon dioxide generation source and the carbon dioxide absorption facility are provided in different locations without being close to each other (when separated), the source gas is changed to CO.₂The distance of the source gas supply piping for supplying to the absorption facility becomes long, and the power for sending the gas as the transport medium is overwhelmingly larger than that of the liquid. Also,Chemical absorption liquidSpecifically, the location where the regenerative equipment is installed is different from the carbon dioxide source.Chemical absorption liquidIt is desirable to be in the vicinity of a heat source for regeneration. this isChemical absorption liquidFrom heat source for regenerationChemical absorption liquidThis is to prevent the temperature from being lowered and the thermal efficiency from being lowered during the transportation of the heat medium by increasing the piping distance for routing the heat medium (process waste gas, combustion gas, etc.) to the regeneration facility through the pipe.
[0070]
  That is, carbon dioxide sources in different locationsChemical absorption liquidRegenerationForWhen combining heat sources, by bringing the carbon dioxide absorption equipment close to the carbon dioxide generation source,Chemical absorption liquidCompared to the material gas piping that requires a large transport powerChemical absorption liquidA different place of carbon dioxide absorption equipment andChemical absorption liquidIt is possible to separate and recover carbon dioxide more efficiently and cheaply when routed between the regenerating facilities. Also in different placesChemical absorption liquidRegenerationForHeat sourceChemical absorption liquidProximity to regeneration facilities is a source of carbon dioxideChemical absorption liquidProximity to regeneration facilities and in different locationsChemical absorption liquidRather than transporting a heat medium from a heat source for regenerationChemical absorption liquidFor playbackofThe distance that the heat medium of the heat source is routed through the pipe can be greatly shortened. Therefore, it is possible to suppress the temperature of the heat source from decreasing, and carbon dioxide can be separated and recovered efficiently and inexpensively.
[0071]
  Specifically, a distance A between the carbon dioxide generation source and the carbon dioxide absorption facility andChemical absorption liquidRegeneration equipment andChemical absorption liquidThe distance B to the heat source for regeneration, and the carbon dioxide absorption facilityChemical absorption liquidIt is desirable that the distance C to the regeneration facility satisfies the relational expression of A <C and B <C (see, for example, FIGS. 10 to 14). Where carbon dioxide absorption equipment andChemical absorption liquidWhen there is a one-to-one relationship with the regeneration facility, it is as described above. However, in the case of one-to-many, many-to-one, and many-to-many,Chemical absorption liquidIt is desirable to satisfy all of the above relationships with the regeneration facility. Also,Chemical absorption liquidAs a heat source for regeneration, if you have multiple stages of process exhaust heat at different temperature levels,Chemical absorption liquidLet B be the distance between the regeneration facility and the heat source with the highest temperature level (see, for example, FIGS. 12 and 14).
[0072]
  More specifically, the carbon dioxide generation sourceBlast furnace gas mainCarbon dioxide-containing gas from carbon dioxide absorption equipmentBlast furnace gasFor supplyingThe length of the pipe (hereinafter referred to asPiping distance)X and saidChemical absorption liquidThe feed pipe distance Y and the return pipe distance Z ofIt is more desirable to satisfy the relational expressions of X <Y, X <Z, W <Y, and W <Z. Furthermore, the piping distances X, Y, Z and W areIt is desirable to satisfy the relational expression 2X <(Y + Z), andChemical absorption liquidFrom heat source for regenerationChemical absorption liquidRegeneration equipmentInAssuming that the piping distance W for supplying heat (for example, process exhaust gas or fuel combustion exhaust gas), it is more desirable to satisfy the relational expression (X + W) <(Y + Z). ThisTheyIn the case ofChemical absorption liquidAs a heat source for regeneration, if you have multiple stages of process exhaust heat at different temperature levels,Chemical absorption liquidThe piping distance between the regeneration facility and the heat source with the highest temperature level is W (for example, see FIGS. 12 and 14).
[0073]
  Also bookinventionThen, one or more carbon dioxide absorption facilities and one or moreChemistryAn absorption liquid regeneration facility may be provided. For example, when there are a plurality of carbon dioxide generation sources, a carbon dioxide absorption facility may be installed in the vicinity thereof. Similarly,Chemical absorption liquidIf the process waste heat that can be used as a heat source for regeneration is divided into multiple places,Chemical absorption liquidRegeneration equipment may be installed. That is, with carbon dioxide absorption equipmentChemistryAbsorption liquid regeneration equipment can take any one-to-one, many-to-one, one-to-many, many-to-many relationship,ChemistryFor absorption liquid regeneration equipment,Chemical absorption liquidIt is desirable in terms of facility costs and running costs that the heat sources of the heat source for regeneration be consolidated.
[0074]
  For example, as shown in FIG. 7 as a many-to-one example, two carbon dioxide absorption facilities 55a and 55b are provided in close proximity to the two carbon dioxide generation sources 53a and 53b, respectively. The delivery pipe 59a and the return pipe 65a, and the delivery pipe 59b and the return pipe 65b are different places, specifically,Chemical absorption liquidRegenerationForOne installed near the heat source 63ChemistryIt is provided between the absorbent regenerator 63. Although FIG. 7 shows an example in which the feed pipe and the return pipe are formed independently, two pipes are integrated into one system on the way andChemistryAbsorbing liquid regeneration facility 63Chemical absorption liquidNeedless to say, when transporting 57 and returning it to the two carbon dioxide absorption facilities 55a and 55b, the two systems may be distributed again.
[0075]
  Also, with carbon dioxide absorption equipmentChemistryWhen any one of the absorbing liquid regeneration facilities is provided, for example, as shown in FIG. 8 as a many-to-many example, the carbon dioxide absorbing facility 55a is close to each of the three carbon dioxide generation sources 53a to 53c. ~ 55c is different from this, specificallyChemical absorption liquidRegenerationForIn proximity to each of the heat sources 63a, 63bChemical absorption liquidRegeneration facilities 61a and 61b are installed. In this case, as the feed pipe and return pipe installed between the three, the three feed pipes 59a to 59c and the return pipes 65a to 65c connected to the three carbon dioxide absorption facilities 55a to 55c are integrated on the way. And redistributing each of the two delivery pipes 59d to 59e and return pipes 65d to 65e.ChemistryYou may make it connect with the absorption medium reproduction | regeneration equipment 61a-61b.
[0076]
  In such a case, the CO required for three carbon dioxide absorption facilities₂Absorption capacity, for example, the amount of raw material gas handled by each carbon dioxide absorption facility and CO in the gas₂If the concentrations are different, the correspondingChemical absorption liquidIt is only necessary to adjust the pipe diameters (areas) of the feed pipes 59a to 59c and the return pipes 65a to 65c and the transport capacity such as a transport pump so that the amount can be supplied. Specifically, when the carbon dioxide absorption amount of each carbon dioxide absorption facility 55a: 55b: 55c is 5: 3: 2, for example, delivery pipes 59a: 59b: 59c (return pipes 65a: 65b: 65c) The piping area or the transport capacity of the pipe may be 5: 3: 2. Similarly, twoChemical absorption liquidRegeneration capacity at the regeneration facility, for example, eachChemical absorption liquidUsed in recycling facilitiesChemical absorption liquidIf the heat source for regeneration is different, take actionChemical absorption liquidThe pipe diameter (area) and the transportation capacity may be adjusted so that the amount can be supplied. Specifically, eachChemical absorption liquidRegeneration equipment 61a: supplied to 61Chemical absorption liquidWhen the amount of heat source for regeneration is 6: 4, for example, the piping area or the transport capacity of the delivery pipe 59d: 59e (return pipe 65d: 65e) may be 6: 4.
[0077]
  In this embodiment,ChemistryAs a heat source (part or all) for regeneration of the absorbing liquid, process exhaust heat at different temperature levels may be provided in multiple stages. this isFirstThis is the same as described (see FIG. 3).In the present inventionLeaveIs,ChemistryUtilizing heat source for absorbing liquid regenerationChemical absorption liquidWhere to heat is directlyChemical absorption liquidIn the regeneration facilityChemical absorption liquidIs not limited toChemical absorption liquidBy providing multiple stages of process exhaust heat at different temperature levels in the regeneration facility,Chemical absorption liquidYou may install so that can be heated. At this time, as shown in FIG. 9, it is desirable to boost up from low-temperature process exhaust heat. In other words, theseChemical absorption liquidWhen the heat sources that can be used as a heat source for regeneration are scattered in a plurality of locations, as shown in FIG.Chemical absorption liquidFor playbackofWhat is necessary is just to utilize as a heat source. At this time, it is only necessary to boost up the process exhaust heat at a low temperature, and the process exhaust heat 63a (heat source temperature T₁) Process heat exhaust 63b (heat source temperature T) which is a higher temperature heat source₂) In order of the feed pipes in the vicinity. Furthermore, the process exhaust heat 63c (heat source temperature T) which is the highest temperature heat source.₃In the vicinity ofChemical absorption liquidA regeneration facility 61 is installed. Where T₁<T₂<T₃It is. As a result, inside the feed pipe 59ChemistryIn the process of absorption liquid passing throughChemical absorption liquidIs gradually preheated to high temperatureChemical absorption liquidIt is sent to the regeneration facility 61 where the amount of heat necessary for regeneration is given and carbon dioxide is separated. It passes through the feed pipeChemical absorption liquidIs usually liquid, but when the feed pipe is heated using a heat source as described above, it is partially vaporized,Chemical absorption liquidIn some cases, carbon dioxide gas may be transported in a state containing a separated gas, but from the viewpoint of reducing transport power, as a heat source used for heating the feed pipe,Chemical absorption liquidIt is desirable to have a temperature that does not vaporize or separate carbon dioxide. In other words,Chemical absorption liquidAs such, a material having a higher density than that of a gas alone is desirable, and particularly a liquid. As long as it does not have a significant influence on the transportation power, a solid or gas may be included as part of the liquid.
[0078]
  MaIn the present inventionLeaveIsUse a cold heat source for the return pipe.Chemical absorption liquidMay be cooled. That is, in the return pipeChemical absorption liquidIs preferably cooled to a lower temperature before being returned to the carbon dioxide absorption facility because of its high carbon dioxide absorption efficiency. So usually,Ahead1-4, as shown inChemical absorption liquidThis is because it is cooled by exchanging heat with other large-scale plants, such as steelworks, because there are cases where cold heat sources are used abundantly and some of them can be used. is there. However, in the present invention, carbon dioxide absorption equipment andChemical absorption liquidSince it is in a place (a distant place) with a different distance from the regeneration facility, it is cooled to near the outside temperature by natural cooling. Therefore, it is particularly effective to use the cold heat source when the outside air temperature is high, such as in summer.
[0079]
  This is the bookinventionAlthough specific examples will be briefly described below with reference to the drawings, it goes without saying that the present invention should not be limited to these. Figures 10-13 show carbon dioxide sources at different locationsChemistryIt is an apparatus (process) figure which represented typically the specific example for isolate | separating and collect | recovering carbon dioxide by combining an absorption liquid reproduction | regeneration heat source. In these drawings, the same reference numerals are given to the constituent elements of the same devices and the like, and the description thereof may be omitted in FIG. 11 and subsequent figures in order to avoid duplication.
[0080]
  (Specific example 1)
  CO shown in FIG.₂ TheSeparation and recoveryDoapparatus(CO ₂ Also called separation and recovery device)100 is
  CO₂CO supplied from the BFG main pipe 93 which is a generation source through the pipe 94₂BFG (CO₂From 20-25% by volume)Chemical absorption liquid97 for CO₂To absorb CO₂An absorption facility (also simply referred to as an absorption tower) 95;
  CO₂AbsorbedChemical absorption liquidFrom 97Chemical absorption liquidSinter cooler as a heat source for regenerationofCO using exhaust heat (250-350 ° C)₂IsolateChemical absorption liquidFor playing 97Chemical absorption liquidRegeneration facility (regeneration tower) 101;
  CO₂Circulates between the absorption tower 95 and the regeneration tower 101 as a transport mediumChemical absorption liquid97,
  Chemical absorption liquid97 is provided with a delivery pipe 99 and a return pipe 105 for transportation.
  The absorption tower 95 is installed close to the BFG main 93, and the regeneration tower 101 is different from the BFG main 93.Chemical absorption liquidIt is installed in the vicinity of the sintering cooler 103a which is a heat source for regeneration.
[0081]
  Therefore, CO using the apparatus 100₂The separation and recovery method is performed by using BFG supplied from the BFG main pipe 93 in the absorption tower 95 adjacent to the BFG main pipe 93, CO 2₂Circulates between the absorption tower 95 and the regeneration tower 101 as a transport mediumChemical absorption liquid97 using CO₂After absorbing
  Chemical absorption liquid97 is sent to the regeneration tower 101 by a delivery pipe 99 for transportation, and the exhaust heat of the sintered cooler is used toChemical absorption liquid97 is heated and CO is regenerated in the regeneration tower 101 at a location different from the BFG main pipe 93.₂To separateChemical absorption liquidA return pipe 105 for transporting 97 is returned to the absorption tower 95 and recycled.
[0082]
  Here, the distance X of the pipe 94 for supplying BFG from the BFG main pipe 93 to the absorption tower 95 is the distance A between the BFG main pipe 93 and the absorption tower 95, and the sintering from the sintering cooler 103a to the regeneration tower 101 is performed. The distance W of the pipe 96 for supplying the cooler exhaust heat = the distance B between the sintering cooler 103a and the absorption tower 95, the distance Y of the delivery pipe 99 = the distance Z of the return pipe 105 = the absorption tower 95 and the regeneration tower 101. The distance C is, A <C and B <C are satisfied, X <Y, X <Z, W <Y and W <Z are satisfied, and2X <(Y + Z), (X + W) <(Y + Z)The relation ofIt is configured to satisfy.
[0083]
  The BFG generated in the blast furnace is supplied as fuel gas to the private power plant in the steelworks and the adjacent thermal power plant through the BFG main. Here, a valve is provided on the BFG main and a part of the BFG Or all CO₂This is advantageous in that carbon dioxide can be removed through the separation and recovery device 100 and supplied to a private power plant or thermal power plant as a fuel with high combustion efficiency (this pointFirstThe same effect as described).
[0084]
  (Specific example 2)
  CO shown in FIG.₂The separation and recovery device 110Chemical absorption liquidHot stove as a heat source for regenerationofExhaust gas (150 to 300 ° C.) (part or all) is used.Chemical absorption liquidThe CO shown in FIG. 10 except that it is installed in the vicinity of the hot stove 103b which is a heat source for regeneration.₂The configuration is the same as that of the separation and recovery device 100.
[0085]
  Therefore, CO using the apparatus 110 is₂The separation and recovery method uses hot stove exhaust gas.Chemical absorption liquidExcept for heating 97, the CO shown in FIG.₂CO using separation and recovery device 100₂This is the same as the separation and recovery method.
[0086]
  Here, the distance X of the pipe 94 is a distance A between the BFG main pipe 93 and the absorption tower 95, and the distance W of the pipe 96 for supplying the hot stove exhaust gas from the hot stove 103b to the regeneration tower 101 is as follows: The distance B to the absorption tower 95, the distance Y of the delivery pipe 99 = the distance Z of the return pipe 105 = the distance C between the absorption tower 95 and the regeneration tower 101, and these relationships are, A <C and B <C are satisfied, X <Y, X <Z, W <Y and W <Z are satisfied, and2X <(Y + Z), (X + W) <(Y + Z)The relation ofIt is configured to satisfy.
[0087]
  (Specific example 3)
  CO shown in FIG.₂Separation and recovery device 120ChemistryIt is an example in which process exhaust heat at different temperature levels is provided in multiple stages (two stages) as part or all of the heat source for absorbing liquid regeneration,Chemical absorption liquidA hot stove as a heat source with a high temperature level among heat sources for regenerationofFlue gas (150-300 ° C) (part or all) and granulated blast furnace slag as a heat source with a low temperature levelofUsing drainage (60-90 ° C), the regeneration tower 101Chemical absorption liquid10 except that it is installed in the vicinity of the hot stove 103b as a heat source for regeneration, and the delivery pipe 99 is arranged so as to pass through a position in the vicinity of the blast furnace granulated slag cooling device 103c. CO₂The configuration is the same as that of the separation and recovery device 100.
[0088]
  Therefore, CO using the above device 120₂In the separation and recovery method, first, the blast furnace granulated slag drainage is used to supply the feed pipe 99.Chemical absorption liquidAfter heating (preheating) 97, using hot stove exhaust gasChemical absorption liquidExcept for heating 97, the CO shown in FIG.₂CO using separation and recovery device 100₂This is the same as the separation and recovery method.
[0089]
  Here, the distance X of the pipe 94 is a distance A between the BFG main pipe 93 and the absorption tower 95, and the distance W of the pipe 96 for supplying the hot stove exhaust gas from the hot stove 103b to the regeneration tower 101 is as follows: The distance B to the absorption tower 95, the distance Y of the delivery pipe 99 = the distance Z of the return pipe 105 = the distance C between the absorption tower 95 and the regeneration tower 101, and these relationships are, A <C and B <C are satisfied, X <Y, X <Z, W <Y and W <Z are satisfied, and2X <(Y + Z), (X + W) <(Y + Z)The relation ofIt is configured to satisfy.
[0090]
  (Specific example 4)
  CO shown in FIG.₂The separation and recovery device 130 is a CO₂CO through a pipe 94a from a private power plant (joint thermal power plant) 93a in the steelworks that is the source₂Combustion exhaust gas (CO₂10 except that the concentration is 8 to 20% by volume) supplied to the absorption tower 95.₂The configuration is the same as that of the separation and recovery device 100.
[0091]
  Therefore, CO using the apparatus 130 is₂In the separation and recovery method, an absorption tower 95 adjacent to the private power plant 93a in the steel works is used to remove the combustion exhaust gas supplied from the private power plant 93a.Chemical absorption liquid97 using CO₂10 except that it absorbs CO.₂CO using separation and recovery device 100₂This is the same as the separation and recovery method.
[0092]
  Here, the distance X of the pipe 94a is the distance A between the private power plant 93a and the absorption tower 95, and the distance W of the pipe 96 for supplying the exhaust heat of the sintering cooler from the sintering cooler 103a to the regeneration tower 101 The distance B between the cooling cooler 103a and the absorption tower 95, the distance Y of the delivery pipe 99 = the distance Z of the return pipe 105 = the distance C between the absorption tower 95 and the regeneration tower 101, and these relationships are, A <C and B <C are satisfied, X <Y, X <Z, W <Y and W <Z are satisfied, and2X <(Y + Z), (X + W) <(Y + Z)The relation ofIt is configured to satisfy.
[0093]
  In addition, in the private power plant in the steelworks, BFG or the CO shown in FIGS.₂Thermal power generation can be performed using BFG from which carbon dioxide has been removed using a separation and recovery device and heavy oil as fuel. CO of the above combustion exhaust gas₂The concentration of 8 to 20% by volume is an example when normal BFG and heavy oil are used.
[0094]
  (Specific example 5)
  CO shown in FIG.₂The separation / recovery device 140 is made of CO.₂CO from the thermal power plant 93b (adjacent to the steel plant), which is the source, through the pipe 94b₂Combustion exhaust gas (CO₂Concentration 8-15 vol%) is supplied to the absorption tower 95,
  furtherChemistryIt is an example in which the process waste heat of steelworks of different temperature levels is provided in multiple stages (three stages) as a heat source for absorbing liquid regeneration,Chemical absorption liquidSinter cooler exhaust heat (250-350 ° C.) as the heat source with the highest temperature level among the heat sources for regeneration, and hot-blast furnace exhaust gas (150-300 ° C.) (part or all) as the heat source with the next highest temperature level And blast furnace granulated slag cooling water (60 to 90 ° C.) as a heat source having a lower temperature level, where the regeneration tower 101 is different from the thermal power plant 93b.Chemical absorption liquidExcept that it is installed in the vicinity of the sintering cooler 103a which is a heat source for regeneration, and the delivery pipe 99 is arranged so as to pass through a position in the vicinity of the blast furnace granulated slag cooling device 103c and the hot air furnace 103b. , CO shown in FIG.₂The configuration is the same as that of the separation and recovery device 100.
[0095]
  Therefore, CO using the device 140 is₂In the separation and recovery method, the combustion exhaust gas supplied from the thermal power plant 93b is absorbed by an absorption tower 95 adjacent to the thermal power plant 93b adjacent to the steel plant.Chemical absorption liquid97 using CO₂In order to absorb and absorb the heat from the low-temperature process exhaust heat, the blast furnace granulated slag drainage and then the hot-blast furnace exhaust gas are used in the delivery pipe 99.Chemical absorption liquidAfter heating (preheating) 97, use the exhaust heat from the sintering coolerChemical absorption liquidExcept for heating 97, the CO shown in FIG.₂CO using separation and recovery device 100₂This is the same as the separation and recovery method.
[0096]
  Here, the distance X of the pipe 94b = the distance A between the thermal power plant 93b and the absorption tower 95, and the distance W of the pipe 96 for supplying the exhaust heat of the sintering cooler from the sintering cooler 103a to the regeneration tower 101 = burning. The distance B between the cooling cooler 103a and the absorption tower 95, the distance Y of the delivery pipe 99 = the distance Z of the return pipe 105 = the distance C between the absorption tower 95 and the regeneration tower 101, and these relationships are, A <C and B <C are satisfied, X <Y, X <Z, W <Y and W <Z are satisfied, and2X <(Y + Z), (X + W) <(Y + Z)The relation ofIt is configured to satisfy.
[0097]
  BookinventionCarbon dioxide using chemical absorption, applicable inTheSeparation and recoveryDoAs the process (apparatus and method), the above-mentioned “carbon dioxide absorption facility is installed in the vicinity of the carbon dioxide generation source,Chemical absorption liquidThere is no particular limitation as long as it satisfies the requirement that the regeneration facility is installed at a location different from the carbon dioxide generation source. Therefore, after absorbing carbon dioxide with the chemical absorption liquid from the raw material gas containing carbon dioxide (by-product gas generated at steelworks and its combustion exhaust gas), which is another requirement, the chemical absorption liquid is heated to separate the carbon dioxide. Carbon dioxide separation and recovery technology using chemical absorption methods, such as the type, concentration and volume of chemical absorption liquid used in the process, apparatus configuration of the process, conditions such as temperature and pressure in the process, various control methods, etc. It is already known and many improvements have been made.inventionNeedless to say, these techniques can be applied to the separation and recovery process described above, but since these techniques are published in many known documents and patent publications, a detailed description thereof is omitted here.
[0098]
  (How to use by-product gas after carbon dioxide extraction)
  In this regard,FirstSince it is the same as that described, description thereof is omitted here.
[0099]
  (Utilization of raw material gas after carbon dioxide extraction)
  Mainly at cement plants and thermal power plants other than steelworks, the raw material gas after carbon dioxide extraction can be used in the same way as for the by-product gas at steelworks. If it cannot be used, it will be exhausted without being used (see FIGS. 13 and 14).
[0100]
    (How to use separated and recovered carbon dioxide; Method and apparatus for immobilization)
  In this regard,What is necessary is just to have equipment for fixing the carbon dioxide recovered by the above-described apparatus for separating and recovering carbon dioxide in the ground or in the sea.Since it is the same as that described, description thereof is omitted here.
[0101]
【The invention's effect】
  According to the present invention, the following effects can be obtained.
[0102]
  1) Separation and recovery equipment can be made compact by separating and recovering carbon dioxide from the by-product gas (unburned gas) of a steel mill, which has a higher carbon dioxide ratio than the combustion exhaust gas of a thermal power plant. Although it depends on the raw material gas used, for example, when BFG of an ironworks is used as raw material gas for a low concentration carbon dioxide combustion exhaust gas of a coal-fired power plant, the equipment cost can be reduced by 30% or more.
[0103]
  2) Use low-grade energy at 0 to 500 ° C, preferably 350 ° C or less, in steelworks.UseAs a result, the running cost of carbon dioxide separation and recovery by the chemical absorption method can be reduced. Specifically, the thermal energy required for heating the chemical absorption liquid in the regeneration tower used in the chemical absorption method is a dominant factor (about 50 to 80%) of the operating cost of this method, Low-grade exhaust heatForTherefore, the total running cost can be greatly reduced.
[0104]
  3) By separating and recovering carbon dioxide from the by-product gas and its combustion exhaust gas, it is possible to improve the thermal efficiency when using the by-product gas as fuel in the subsequent stage. Although it depends on the raw material gas used, for example, when BFG of an ironworks is used as the raw material gas, it can be improved by about 20-30%.
[0105]
  4) Further, with respect to the combustion exhaust gas after using the by-product gas (unburned gas) as a fuel gas, the carbon dioxide ratio is higher, so the carbon dioxide separation and recovery equipment can be further miniaturized. The amount of carbon dioxide emission reduction (separation recovery amount) can be increased.
[0106]
  Further, in the present invention, since the effects 1) to 4) can be enjoyed at a time, carbon dioxide can be separated and recovered at a very low cost. Therefore, the present invention can be used industrially even in an iron manufacturing plant with severe cost competition. Technology. Further, the recovered carbon dioxide can be used as a reducing gas in the steelworks, for example, in top gas recycling of a blast furnace. Therefore, the reducing agent can be reduced, and the amount of coke used in the blast furnace and CO₂The increase in total cost at the steelworks can be remarkably suppressed (in some cases, the cost can be reduced). In addition, as described above, a number of technologies capable of converting the collected carbon dioxide into valuable products have been proposed (including technologies newly found by the present inventors), and in combination with these technologies, the product cost can be increased. It is possible to provide a very useful technology that can be suppressed (the total cost can be reduced depending on the commercial value of carbon dioxide) and can contribute effectively to the prevention of global warming.
[0107]
  In accordance with the present invention, carbon dioxide sources at different locationsChemistryAbsorption liquid regenerationForBy combining the heat sources, carbon dioxide can be separated and recovered from the carbon dioxide generation source efficiently and inexpensively.
[Brief description of the drawings]
FIG. 1 is a principle diagram of a process for separating and recovering carbon dioxide from a source gas containing carbon dioxide by a chemical absorption method.
[FIG. 2] In order to separate and recover carbon dioxide from the raw material gas generated at the steelworks by the chemical absorption method using the exhaust heat generated at the steelworks using the total amount of heat necessary for the regeneration of the chemical absorbent. It is drawing which represented this process typically.
[Figure 3] Depending on the characteristics of the chemical absorbent, appropriate exhaust heat generated at the steelworks for the regeneration of the chemical absorbent can be used in multiple stages to convert the raw material gas generated at the steelworks to the chemical absorption method. 2 is a diagram schematically showing a process for separating and recovering carbon dioxide.
[Fig. 4] Exhaust heat generated at steelworks for regeneration of chemical absorption liquidUseAnd steam for the factoryUseFIG. 2 is a diagram schematically showing a process for separating and recovering carbon dioxide from a raw material gas generated at an ironworks by a chemical absorption method.
FIG. 5 shows the present invention.Cost ofIt is a drawing schematically showing a typical device, and carbon dioxide generation sources at different locations.ChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
FIG. 6OtherIs a diagram schematically showing a typical apparatus of carbon dioxide generation sources at different locations.ChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
FIG. 7MoreIs a diagram schematically showing another representative apparatus, and carbon dioxide generation sources in different locations.ChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
FIG. 8MoreFIG. 5 is a diagram schematically showing another typical apparatus, and carbon dioxide generation sources in different locations.ChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
FIG. 9AnotherIs a diagram schematically showing a typical apparatus of carbon dioxide generation sources at different locations.ChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
FIG. 10 shows the present invention.IngredientsIt is drawing which represented the apparatus used for the example 1 typically, Comprising: The carbon dioxide generation source in a different placeChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
FIG. 11 shows the present invention.IngredientsIt is drawing which represented the apparatus used for the example 2 typically, Comprising: The carbon dioxide generation source in a different placeChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
FIG. 12 shows the present invention.IngredientsIt is drawing which represented the apparatus used for the example 3 typically, Comprising: The carbon dioxide generation source in a different place andChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
FIG. 13 shows the present invention.IngredientsIt is drawing which represented the apparatus used for the example 4 typically, Comprising: The carbon dioxide generation source in a different place andChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
FIG. 14 shows the present invention.IngredientsIt is drawing which represented the apparatus used for the example 5 typically, Comprising: The carbon dioxide generation source in a different placeChemistryAbsorption liquid regenerationForIt is an apparatus (process) figure for separating and recovering carbon dioxide by combining heat sources.
[Explanation of symbols]
  1 ... absorption tower, 3 ... raw material gas (by-product gas),
  5 ... Chemical absorption solution, 5 '... Regeneration absorption solution,
  6 ... Delivery piping, 7 ... Regeneration tower,
  8 ... return piping, 9 ... heating medium,
  10 ... heat exchanger, 11 ... carbon dioxide separated and recovered,
  13 ... By-product gas after carbon dioxide separation, 15 ... By-product gas piping,
  50, 60, 70, 80, 90, 100, 110, 120, 130, 140 ... CO₂Separation and recovery equipment,
  53, 53a, 53b, 53c ... CO₂Generation source,
  55, 55a, 55b, 55c ... CO₂Absorption equipment,
  57, 57a, 57b, 57c, 57d, 57e ...Chemical absorption liquid,
  59, 59a, 59b, 59c, 59d, 59e ... delivery piping,
  61, 61a, 61b ...Chemical absorption liquidRegeneration equipment,
  63 ...Chemical absorption liquidHeat source for regeneration, 63a, 63b ... process exhaust heat,
  65, 65a, 65b, 65c, 65d, 65e ... return piping,
  93 ... BFG main, 93a ... Private power plant (joint thermal power plant),
  93b ... thermal power plant, 94, 94a, 94b ... piping,
  95 ... CO₂Absorption equipment (absorption tower), 97…Chemical absorption liquid,
  99 ... Delivery piping, 101 ...Chemical absorption liquidRegeneration equipment (regeneration tower),
  103a ... sintering cooler, 103b ... hot stove,
  103c ... Blast furnace granulated slag cooling device, 105 ... Return pipe.

Claims (4)

An apparatus for separating and recovering carbon dioxide from blast furnace gas, having an apparatus for separating and recovering carbon dioxide and an apparatus for fixing carbon dioxide,
The device that separates and recovers carbon dioxide
A carbon dioxide absorption facility for absorbing carbon dioxide from the blast furnace gas supplied from the blast furnace gas main for transporting the blast furnace gas from the blast furnace to the next process of the steel plant, with a chemical absorption liquid;
A chemical absorption liquid regeneration facility for separating carbon dioxide from a chemical absorption liquid that has absorbed carbon dioxide using a heat source for chemical absorption liquid regeneration and regenerating the chemical absorption liquid ;
And delivery pipes for the transport of chemical absorbent that has absorbed carbon dioxide to chemical absorption solution regeneration facilities from carbon dioxide absorption equipment,
And a return pipe for the transport of chemical absorbent that has regenerated to carbon dioxide absorption equipment from chemical absorption liquid regeneration equipment,
The device that immobilizes carbon dioxide
Include provisions for immobilizing carbon dioxide recovered by the apparatus for separating and recovering the carbon dioxide in the ground or the sea,
As a heat source for chemical absorption liquid regeneration, low-grade exhaust heat of 500 ° C or less generated at steelworks is used.
Blast furnace and the length X of the pipe for supplying the blast furnace gas to the carbon dioxide absorption equipment from mains gas, the feed pipes of a chemical absorption liquid return pipe length Y and length Z, chemical absorption liquid for reproduction dioxide and length W of the pipe for supplying heat to the chemical absorbing liquid regeneration equipment from heat source, to X <Y, X <Z, W <Y and W <satisfies the Z relationship, A device that separates and recovers and immobilizes carbon. An apparatus for separating and recovering carbon dioxide from blast furnace gas, having an apparatus for separating and recovering carbon dioxide and an apparatus for fixing carbon dioxide,
The device that separates and recovers carbon dioxide
A carbon dioxide absorption facility for absorbing carbon dioxide from the blast furnace gas supplied from the blast furnace gas main for transporting the blast furnace gas from the blast furnace to the next process of the steel plant, with a chemical absorption liquid;
A chemical absorption liquid regeneration facility for separating carbon dioxide from the chemical absorption liquid that has absorbed carbon dioxide using a heat source for chemical absorption liquid regeneration and regenerating the chemical absorption liquid;
A delivery pipe for transporting the chemical absorption liquid that has absorbed carbon dioxide from the carbon dioxide absorption equipment to the chemical absorption liquid regeneration equipment;
A return pipe for transporting the chemical absorbent regenerated from the chemical absorbent regenerator to the carbon dioxide absorber,
The device that immobilizes carbon dioxide
It has equipment for fixing the carbon dioxide recovered by the device for separating and recovering carbon dioxide described above to the ground or the sea,
As a heat source for chemical absorption liquid regeneration, low-grade exhaust heat of 500 ° C or less generated at steelworks is used.
Blast furnace and the length X of the pipe for supplying the blast furnace gas to the carbon dioxide absorption equipment from mains gas, the feed pipes of a chemical absorption liquid return pipe length Y and length Z, chemical absorption liquid for reproduction The length W of the pipe for supplying heat from the heat source to the chemical absorption liquid regeneration facility satisfies at least one of the relational expression 2X <(Y + Z) or the relational expression (X + W) <(Y + Z). apparatus for separating and recovering immobilized carbon dioxide you characterized by. Blast furnace gas supplied from this high-furnace gas main pipe at close proximity to the carbon dioxide absorption equipment blast furnace gas main pipe for transporting the next step into the blast furnace gas in a steel plant blast furnace, using a chemical absorbent solution dioxide After absorbing carbon
Heating the chemical absorption liquid using a heat source for chemical absorption liquid regeneration, separating and recovering carbon dioxide in a chemical absorption liquid regeneration facility adjacent to the heat source for chemical absorption liquid regeneration,
A method for separating and recovering carbon dioxide from a blast furnace gas of a carbon dioxide generation source, which is characterized in that it is fixed in the ground or in the sea by a facility for fixing the recovered carbon dioxide,
As a heat source for regenerating the chemical absorbent, low-grade exhaust heat of 500 ° C. or less generated at a steel mill is used,
I feed for blast furnace and the length X of the pipe for supplying the blast furnace gas to the carbon dioxide absorption equipment from mains gas, transported from the carbon dioxide absorption equipment chemical absorption liquid chemical absorbent that has absorbed carbon dioxide to the reproduction equipment The length Y of the pipe, the length Z of the return pipe for transporting the chemical absorption liquid regenerated from the chemical absorption liquid regeneration equipment to the carbon dioxide absorption equipment, and the heat source for chemical absorption liquid regeneration to the chemical absorption liquid regeneration equipment a length W of a pipe for supplying heat to X <Y, X <Z, W <Y and W <carbon dioxide separated and recovered immobilized, characterized by satisfying the relationship of Z, Method. Carbon dioxide is absorbed from the blast furnace gas supplied from the blast furnace gas main in the carbon dioxide absorption facility adjacent to the blast furnace gas main for transporting the blast furnace gas from the blast furnace to the next process of the steel plant. After absorption
Heating the chemical absorption liquid using a heat source for chemical absorption liquid regeneration, separating and recovering carbon dioxide in a chemical absorption liquid regeneration facility adjacent to the heat source for chemical absorption liquid regeneration,
A method for separating and recovering carbon dioxide from a blast furnace gas of a carbon dioxide generation source, which is characterized in that it is fixed in the ground or in the sea by a facility for fixing the recovered carbon dioxide,
As a heat source for regenerating the chemical absorbent, low-grade exhaust heat of 500 ° C. or less generated at a steel mill is used,
Feed for blast furnace and the length X of the pipe for supplying the blast furnace gas to the carbon dioxide absorption equipment from mains gas, transported from the carbon dioxide absorption equipment chemical absorption liquid chemical absorbent that has absorbed carbon dioxide to the reproduction equipment The length Y of the pipe , the length Z of the return pipe for transporting the chemical absorption liquid regenerated from the chemical absorption liquid regeneration equipment to the carbon dioxide absorption equipment, and the heat source for chemical absorption liquid regeneration to the chemical absorption liquid regeneration equipment a length W of a pipe for supplying the heat, you and satisfies the 2X <(Y + Z) relationship or (X + W) <(Y + Z) at least one relationship of the relationship type secondary A method of separating and recovering and fixing carbon oxides.

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