Reaction apparatus, reaction method, pulp manufacturing equipment, and pulp manufacturing method

Abstract

To efficiently recycle and reuse calcium carbonate emitted in a causticizing step while suppressing emission of carbon dioxide.SOLUTION: A reaction apparatus comprises a first reaction part including a first reactor for generating carbon monoxide and calcium hydroxide by reacting calcium carbonate with hydrogen, a first inlet port for supplying calcium carbonate to the first reactor, a second inlet port for supplying hydrogen to the first reactor, and an outlet port for emitting a reaction product including carbon monoxide and calcium hydroxide from the first reactor, and is constituted in a manner that calcium carbonate from a second reactor for converting sodium carbonate to sodium hydroxide is supplied to the first reactor via the first inlet port, and the calcium hydroxide formed in the first reactor is supplied to the second reactor via the outlet port.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a reaction apparatus and a reaction method, as well as a pulp manufacturing facility and a pulp manufacturing method.

Background Art

[0002] In a pulp manufacturing facility (such as a paper mill), wood chips are cooked using sodium hydroxide (caustic soda) to produce pulp. The black liquor discharged in the cooking process is concentrated and burned in a recovery boiler. The combustion residue (smelt) generated in the recovery boiler contains sodium carbonate, and this sodium carbonate is converted to sodium hydroxide in the causticizing process and reused for cooking wood chips.

[0003] In the above-mentioned causticizing process, usually, calcium hydroxide (Ca(OH)2) is obtained by adding calcium oxide to green liquor (a solution containing sodium carbonate) obtained by dissolving the smelt (the following formula (A)), and by reacting the calcium hydroxide thus obtained with sodium carbonate (Na2CO3) in the green liquor, sodium hydroxide (NaOH) and calcium carbonate (CaCO3) are generated (the following formula (B)). CaO + H2O → Ca(OH)2…(A) Na2CO3 + Ca(OH)2 → 2NaOH + CaCO3…(B)

[0004] Patent Document 1 describes that calcium carbonate generated in the causticizing process is calcined to calcium oxide and recycled to the causticizing process for reuse.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When recycling calcium carbonate discharged in the causticization process and reusing it in the causticization process, it is desirable to efficiently convert calcium carbonate into a form that can be used in the causticization process.

[0007] Also, for example, as described in Patent Document 1, when calcium carbonate generated in the causticization process is fired, as shown in the following formula (C), calcium carbonate thermally decomposes to generate calcium oxide and carbon dioxide, which is a greenhouse gas. CaCO3 → CaO + CO2…(C) Therefore, in the process of recycling calcium carbonate discharged in the causticization process, it is desirable to suppress the emission of carbon dioxide.

[0008] In view of the above circumstances, at least one embodiment of the present invention aims to provide a reaction apparatus, a reaction method, a pulp manufacturing facility, and a pulp manufacturing method capable of efficiently recycling and reusing calcium carbonate discharged in the causticization process while suppressing the emission of carbon dioxide.

Means for Solving the Problems

[0009] The reaction apparatus according to at least one embodiment of the present invention includes a first reaction section for generating carbon monoxide and calcium hydroxide from calcium carbonate and hydrogen, The first reaction section includes a first reactor for reacting the calcium carbonate and the hydrogen to generate the carbon monoxide and the calcium hydroxide, a first inlet port for supplying the calcium carbonate to the first reactor, a second inlet port for supplying the hydrogen to the first reactor, and an outlet port for discharging a reaction product containing the carbon monoxide and the calcium hydroxide from the first reactor, and Calcium carbonate from the second reaction section for converting sodium carbonate to sodium hydroxide is supplied to the first reaction section through the first inlet port, and the calcium hydroxide generated in the first reaction section is supplied to the second reaction section through the outlet port.

[0010] Also, a pulp manufacturing facility according to at least one embodiment of the present invention includes the above-described reactor, and a digestion apparatus configured to digest wood using the sodium hydroxide from the second reaction section. It is provided with.

[0011] Also, a reaction method according to at least one embodiment of the present invention includes a step of supplying calcium carbonate from a second reaction section for converting sodium carbonate to sodium hydroxide to a first reaction section, a step of reacting the calcium carbonate and hydrogen in the first reaction section to produce carbon monoxide and calcium hydroxide, a step of supplying the calcium hydroxide generated in the first reaction section to the second reaction section, It is provided with.

[0012] Also, a pulp manufacturing method according to at least one embodiment of the present invention includes a step of performing the above-described reaction method, a step of digesting wood using the sodium hydroxide from the second reaction section, It is provided with.

Effect of the Invention

[0013] According to at least one embodiment of the present invention, there are provided a reactor and a reaction method, and a pulp manufacturing facility and a pulp manufacturing method capable of efficiently recycling and reusing calcium carbonate discharged in a causticization process while suppressing carbon dioxide emissions.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

[0015] Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples.

[0016] FIG. 1 is a schematic diagram of a pulp manufacturing facility to which a reactor according to some embodiments is applied. FIGS. 2 and 3 are schematic diagrams of a reactor according to an embodiment, respectively.

[0017] As shown in FIG. 1, a pulp manufacturing facility 100 according to an embodiment includes a digester 2 for digesting wood such as wood chips, and a reactor 1 including a first reaction section 10 described later. The pulp manufacturing facility 100 may include a recovery boiler (soda recovery boiler) 6 for burning the black liquor discharged from the digester 2, and / or a causticizing section 8 for causticizing the green liquor containing the combustion residue (smelt) generated in the recovery boiler 6.

[0018] The digester 2 is configured to digest raw material wood (such as wood chips) using sodium hydroxide (NaOH). The digester 2 may include a digester for treating the raw material wood with a chemical solution containing sodium hydroxide. By adding a chemical solution containing sodium hydroxide to the raw material wood and performing a digestion treatment at a high temperature, the raw material wood becomes pulp, which is a fiber component (cellulosic), and black liquor in which the resin component (ligninous) is dissolved. The pulp taken out from the digester 2 becomes a product through a washing process, a bleaching process, etc. The pulp thus manufactured can be used, for example, as a raw material for paper.

[0019] The digester 2 may be configured to be supplied with sodium hydroxide from the causticizing section 8 described later.

[0020] The black liquor discharged from the digester 2 is typically concentrated in the evaporator 4 and then burned in the recovery boiler 6. The combustion gas generated by the combustion of the black liquor containing lignin in the recovery boiler 6 contains carbon dioxide (CO2). The combustion gas containing carbon dioxide is discharged from the recovery boiler 6 as exhaust gas through the exhaust gas line 68.

[0021] The combustion residue (smelt) generated by the combustion of the black liquor in the recovery boiler 6 contains sodium carbonate (Na2CO3) and is recovered from the recovery boiler 6. The solution of sodium carbonate (green liquor; Green liquor) obtained by dissolving this smelt is causticized in the causticizing section 8.

[0022] The causticizing section 8 is configured to react sodium carbonate contained in the green liquor with calcium hydroxide (Ca(OH)2) to produce sodium hydroxide and calcium carbonate (CaCO3). The sodium hydroxide produced in the causticizing section 8 is supplied to the digester 2 and reused for digesting the raw wood. The calcium carbonate produced in the causticizing section 8 is configured to be supplied to the first reaction section 10 described later.

[0023] The first reaction section 10 is configured to react calcium carbonate (CaCO3) with hydrogen (H2) to produce carbon monoxide (CO) and calcium hydroxide (Ca(OH)2). As shown in FIG. 2, the first reaction section 10 includes a first reactor 16 for reacting calcium carbonate with hydrogen, a first inlet port 18 for supplying calcium carbonate to the first reactor 16, a second inlet port 20 for supplying hydrogen to the first reactor 16, and an outlet port 22 for discharging the reaction product containing carbon monoxide and calcium hydroxide from the first reactor 16.

[0024] In the embodiments shown in FIGS. 2 and 3, the powdery calcium carbonate (solid) stored in the storage hopper 24 is supplied to the first reactor 16 via the first raw material supply line 19 connected to the first inlet port 18. The powdery calcium carbonate in the storage hopper 24 is received by the pressure hopper 26 and pneumatically conveyed into the first reactor 16 through the first raw material supply line 19 and the first inlet port 18 by the conveying gas G1. The internal pressure of the pressure hopper 26 is maintained at a set pressure higher than the atmospheric pressure by the supply of the pressurizing gas G2. When the pressure hopper 26 is pressurized, the on-off valve 25 provided between the storage hopper 24 and the pressure hopper 26 is closed to cut off the communication between the storage hopper 24 and the pressure hopper 26. Hydrogen or an inert gas (such as nitrogen) can be used as the conveying gas G1 and the pressurizing gas G2.

[0025] In the embodiments shown in FIGS. 2 and 3, gaseous hydrogen from the hydrogen supply source 28 is supplied to the first reactor 16 via the second raw material supply line 21 connected to the second inlet port 20. The hydrogen supply source 28 may include a hydrogen storage tank storing hydrogen, or a hydrogen production device such as a water electrolysis device.

[0026] In the embodiment shown in FIG. 2, the first inlet port 18 and the second inlet port 20 are provided separately, but in some embodiments, the first inlet port 18 and the second inlet port 20 may be a common inlet port. That is, calcium carbonate and hydrogen may be supplied to the first reactor 16 through one inlet port that functions as both the first inlet port 18 and the second inlet port 20.

[0027] The first reactor 16 may be a continuous reactor capable of simultaneously performing the input of raw materials containing calcium carbonate CaCO3 and hydrogen, the reaction in the first reactor 16, and the extraction of products from the first reactor 16.

[0028] The first reactor 16 may be configured to generate carbon monoxide and calcium hydroxide using calcium carbonate and hydrogen as raw materials. The reaction formula for generating carbon monoxide and calcium hydroxide from calcium carbonate and hydrogen is represented by the following formula (D). CaCO3 + H2 → CO + Ca(OH)2…(D)

[0029] Note that the present inventors have confirmed that the reaction of the above formula (D) occurs under considerably lower temperature conditions (700°C or lower without a catalyst, 600°C or lower with a catalyst) compared to the temperature conditions of 900°C or higher where the thermal decomposition reaction of calcium carbonate represented by the following formula (C) is dominant. CaCO3 → CaO + CO2…(C)

[0030] The first reactor 16 may be configured to react calcium carbonate and hydrogen under temperature conditions lower than the temperature range (about 900°C or higher) where the thermal decomposition reaction of calcium carbonate is dominant. The first reactor 16 may be configured to react calcium carbonate and hydrogen, for example, under temperature conditions of 300°C or higher and 700°C or lower (i.e., in a state where the internal temperature is 300°C or higher and 700°C or lower).

[0031] Note that the reaction of the above formula (D) is an endothermic reaction. Therefore, in order to maintain the first reactor 16 under appropriate temperature conditions, the first reactor 16 or the raw material (calcium carbonate or hydrogen) supplied to the first reactor 16 or the carrier gas (for example, the above-described carrier gas G1) may be heated by the heating unit 30. In the exemplary embodiments shown in FIGS. 2 and 3, the reaction apparatus 1 includes a heating unit 30 (such as an electric heater, a combustion device, or a heat exchanger) for heating the hydrogen gas supplied to the first reactor 16. The heating units 30 shown in FIGS. 2 and 3 include heat exchangers 31, 32 provided in the second raw material supply line 21.

[0032] The heating unit 30 may be configured to heat the first reactor 16 or the hydrogen supplied to the first reactor 16 using a heat medium HM heated by utilizing the reaction heat of carbon monoxide and hydrogen in the fuel synthesis unit 34 described later. In the exemplary embodiments shown in FIGS. 2 and 3, the heat exchanger 31 is configured to heat the hydrogen in the second raw material supply line 21 by heat exchange with the heat medium HM heated in the fuel synthesis unit 34.

[0033] A catalyst 17 for promoting the reaction of the above formula (D) may be provided inside the first reactor 16. By providing such a catalyst 17 inside the first reactor 16, the rate of the reaction of the above formula (D) can be increased or the reaction can proceed at a lower temperature in the first reactor 16. The catalyst 17 may be, for example, a solid catalyst containing Pt, Ni, Co, Ir, Pd, Ru, Rh, etc. The form of the catalyst 17 is not particularly limited, but from the viewpoint of increasing the specific surface area, it may be granular, plate-like, or honeycomb-like.

[0034] Inside the first reactor 16, solid particles of calcium carbonate move toward the region where the catalyst 17 is disposed in the internal space of the first reactor 16 by the gas flow containing hydrogen in the first reactor 16. When the solid particles of calcium carbonate reach the region where the catalyst 17 is disposed, the reaction of the above formula (D) proceeds rapidly. As a result, in the region on the downstream side of the catalyst 17 in the internal space of the first reactor 16, a solid-gas two-phase flow in which solid particles containing calcium hydroxide float in the gas containing carbon monoxide is formed. Then, the solid-gas two-phase flow containing calcium hydroxide and carbon monoxide (reaction product) is discharged through the outlet port 22.

[0035] The solid-gas two-phase flow containing the reaction product discharged from the outlet port 22 is separated into solid particles containing calcium hydroxide and a gas containing carbon monoxide. For this purpose, in the exemplary embodiments shown in FIGS. 2 and 3, the reaction apparatus 1 includes a solid-gas separation device 36 connected to the outlet port 22 of the first reactor 16 via a discharge line 23. The solid-gas separation device 36 may include at least one of a filter or a cyclone.

[0036] As shown in FIGS. 2 and 3, the solid particles containing calcium hydroxide separated from the solid-gas two-phase flow by the solid-gas separator 36 may be stored in the storage unit 38.

[0037] As shown in FIGS. 2 and 3, the gas containing carbon monoxide separated from the solid-gas two-phase flow by the solid-gas separator 36 may be discharged from the solid-gas separator 36 and supplied to the carbon demand destination. In the exemplary embodiment shown in FIGS. 2 and 3, the reactor 1 includes a fuel synthesis unit (fuel synthesis apparatus) 34 for performing fuel synthesis using carbon monoxide and hydrogen, and a CO gas line 37 provided between the solid-gas separator 36 and the fuel synthesis unit 34. Then, the gas containing carbon monoxide discharged from the solid-gas separator 36 is supplied to the fuel synthesis unit 34 via the CO gas line 37.

[0038] The fuel synthesis unit 34 may be configured to produce carbon-containing fuels such as light oil, methanol, dimethyl ether, and methane using carbon monoxide and hydrogen as raw materials.

[0039] In some embodiments, the reactor 1 may include a second reaction unit 12 for converting sodium carbonate into sodium hydroxide. In the exemplary embodiment shown in FIGS. 1 and 2, the reactor 1 includes, as the second reaction unit 12, a causticization unit 8 configured to react sodium carbonate contained in green liquor (a solution of sodium carbonate), which is a melt solution generated in the recovery boiler 6 (see FIG. 1), with calcium hydroxide to produce sodium hydroxide and calcium carbonate.

[0040] As shown in FIGS. 1 and 2, in some embodiments, calcium carbonate from the second reaction unit 12 is supplied to the first reaction unit 10 through the first inlet port 18 (not shown in FIG. 1), and calcium hydroxide generated in the first reaction unit 10 is supplied to the second reaction unit 12 through the outlet port 22.

[0041] As shown in FIGS. 1 and 2, the reactor 1 may include a first supply line 102 for supplying calcium carbonate from the second reaction section 12 to the first reaction section 10 via the first inlet port 18, and a second supply line 104 for supplying calcium hydroxide from the outlet port 22 of the first reaction section 10 to the second reaction section 12.

[0042] In the exemplary embodiment shown in FIG. 2, the second reaction section 12 (causticizing section 8) includes a second reactor 40 for reacting green liquor with calcium hydroxide.

[0043] The green liquor is supplied to the second reactor 40, for example, via a green liquor supply line 42.

[0044] An aqueous solution containing calcium hydroxide is also supplied to the second reactor 40 via a supply line 44. The aqueous solution containing calcium hydroxide may be stored in a solution tank 52. In the solution tank 52, an aqueous solution containing calcium hydroxide is prepared by mixing water and calcium hydroxide from the first reaction section 10.

[0045] In the exemplary embodiment shown in FIG. 2, solid particles containing calcium hydroxide stored in the storage section 38 (solid particles generated in the first reaction section 10 and separated by the solid-gas separator 36) are pneumatically conveyed by a carrier gas G3 through a conveying line 46 to a filter 48, and the solid particles separated from the carrier gas G3 by the filter 48 are received by a storage hopper 50. Then, the solid particles containing calcium hydroxide from the storage hopper 50 and water are supplied to the solution tank 52, and they are mixed in the solution tank 52 to prepare an aqueous solution containing calcium hydroxide.

[0046] The aqueous solution containing calcium hydroxide prepared in the solution tank 52 is supplied to the second reactor 40 via the supply line 44. As shown in FIG. 2, a pump 45 for pumping the aqueous solution containing calcium hydroxide may be provided in the supply line 44.

[0047] In the exemplary embodiment shown in FIG. 2, the above-described second supply line 104 for supplying calcium hydroxide from the outlet port 22 of the first reaction section 10 to the second reaction section 12 includes the above-described transfer line 46.

[0048] In the second reactor 40, sodium hydroxide (aqueous solution) and calcium carbonate (solid) are produced by the reaction of sodium carbonate contained in the green liquor and calcium hydroxide contained in the aqueous solution from the supply line 44.

[0049] The reaction product containing solid particles of sodium hydroxide and calcium carbonate generated in the second reactor 40 is discharged from the second reactor 40 through the discharge line 53 and guided to the solid-liquid separation device 54, where it is separated into solid particles of calcium carbonate and a solution containing sodium hydroxide. As shown in FIG. 2, a pump 55 for pumping the above-described reaction product may be provided in the discharge line 53.

[0050] The solution containing sodium hydroxide separated from the reaction product in the second reactor 40 by the solid-liquid separation device 54 may be supplied to the digester 2 (see FIG. 1) via a solution line 56 or the like and used for digesting wood.

[0051] The solid particles of calcium carbonate separated from the reaction product in the second reactor 40 by the solid-liquid separation device 54 are dried by a drying device 58 such as a conveyor type after being discharged from the solid-liquid separation device 54. The dried solid particles of calcium carbonate are stored in a storage section 60. The solid particles of calcium carbonate in the storage section 60 are pneumatically conveyed to a filter 64 through a transfer line 62 by a transfer gas G4. The solid particles of calcium carbonate separated from the transfer gas G4 by the filter 64 are received in a storage hopper 24. Also, as already described, the solid particles of calcium carbonate in the storage hopper 24 are supplied to the first reactor 16 through the first raw material supply line 19.

[0052] In the exemplary embodiment shown in FIG. 2, the above-described first supply line 102 for supplying calcium carbonate from the second reaction unit 12 to the first reaction unit 10 via the first inlet port 18 includes the above-described transfer line 62.

[0053] In the above-described embodiment, calcium carbonate from the second reaction unit 12 (causticization unit 8) for performing the reaction of converting sodium carbonate to sodium hydroxide (i.e., for performing the causticization process) is supplied to the first reaction unit 10, and calcium hydroxide generated by the reaction of calcium carbonate and hydrogen in the first reaction unit 10 is supplied to the second reaction unit 12. Therefore, in the second reaction unit 12, by reacting calcium hydroxide from the first reaction unit 10 with sodium carbonate, sodium hydroxide can be efficiently obtained by the reaction of the following formula (B) without going through the reaction of the following formula (A) (i.e., the reaction of obtaining calcium hydroxide from calcium oxide). CaO + H2O → Ca(OH)2…(A) Na2CO3+ Ca(OH)2→ 2NaOH + CaCO3…(B) Further, in the first reaction unit 10, in the first reactor 16, calcium carbonate and hydrogen are reacted by the reaction of the following formula (D) to generate carbon monoxide and calcium hydroxide, so carbon dioxide is not generated in the process of obtaining calcium hydroxide from calcium carbonate. CaCO3+ H2→ CO + Ca(OH)2…(D) Therefore, according to the above-described embodiment, while reducing the carbon dioxide emission amount, the calcium carbonate discharged in the causticization process can be efficiently recycled and reused in the causticization process (the above formula (B)).

[0054] Further, in the above-described embodiment, since carbon monoxide is generated by the reaction of the above formula (D) in the first reactor 16, this carbon monoxide can also be effectively utilized as fuel.

[0055] In some embodiments, for example, as shown in FIG. 2, the reaction apparatus 1 may include a third reaction unit 14 for reacting carbon dioxide and calcium hydroxide to generate calcium carbonate.

[0056] The third reaction section 14 may be configured to react carbon dioxide contained in the exhaust gas from the recovery boiler 6 (see FIG. 1) with calcium hydroxide.

[0057] As shown in FIGS. 1 and 2, the reaction apparatus 1 may include a third supply line 106 for supplying calcium carbonate generated in the third reaction section 14 to the first reaction section 10. Further, the reaction apparatus 1 may include a fourth supply line 108 for supplying calcium hydroxide generated in the first reaction section 10 to the third reaction section 14.

[0058] In the exemplary embodiment shown in FIG. 2, the third reaction section 14 includes an absorption tower 66 configured to supply the exhaust gas from the recovery boiler 6 (see FIG. 1) and absorb carbon dioxide contained in the exhaust gas into an absorption liquid, and a third reactor 76 configured to supply the absorption liquid from the absorption tower 66 and calcium hydroxide.

[0059] The exhaust gas from the recovery boiler 6 is supplied to the absorption tower 66 via an exhaust gas line 68. The absorption tower 66 is provided with an absorption liquid supply section 70 for supplying the absorption liquid inside the absorption tower 66. In the absorption tower 66, carbon dioxide contained in the exhaust gas is absorbed into the absorption liquid by contact between the exhaust gas from the exhaust gas line 68 and the absorption liquid from the absorption liquid supply section 70. As the absorption liquid, for example, an aqueous solution such as potassium hydroxide (KOH) or sodium hydroxide (NaOH) can be used. When potassium hydroxide is used as the absorption liquid, the reaction in which carbon dioxide is absorbed into the absorption liquid is represented by the following formula (E). 2KOH + CO2→ K2CO3+ H2O …(E)

[0060] At the bottom of the absorption tower 66, a solution that has absorbed carbon dioxide (i.e., an aqueous solution containing potassium carbonate) is stored. The solution stored at the bottom of the absorption tower 66 is supplied to the third reactor 76 via a solution supply line 74. The solution supply line 74 may be provided with a pump 75 for pumping the solution.

[0061] Incidentally, the exhaust gas from which carbon dioxide has been removed or reduced by contact with the absorption liquid is discharged from the top of the absorption tower 66.

[0062] In addition, an aqueous solution containing calcium hydroxide is supplied to the third reactor 76 via the supply line 44 described above. In the third reactor 76, potassium hydroxide (aqueous solution) and calcium carbonate (solid) are produced by the reaction between potassium carbonate contained in the solution supplied from the absorption tower 66 and calcium hydroxide contained in the solution supplied from the supply line 44 (the following formula (F)). K2CO3 + Ca(OH)2 → 2KOH + CaCO3…(F)

[0063] The reaction product containing solid particles of potassium hydroxide and calcium carbonate produced in the third reactor 76 is discharged from the third reactor 76 via the discharge line 78 and led to the solid-liquid separation device 80, where it is separated into solid particles of calcium carbonate and a solution containing potassium hydroxide. As shown in FIG. 2, a pump 79 for pumping the above-described reaction product may be provided in the discharge line 78.

[0064] The solution containing potassium hydroxide separated from the reaction product in the third reactor 76 by the solid-liquid separation device 80 may be returned to the absorption liquid supply section 70 of the absorption tower 66 via the absorption liquid supply line 82 and used again as the absorption liquid. As shown in FIG. 2, a pump 83 for pumping the potassium hydroxide solution (absorption liquid) from the solid-liquid separation device 80 may be provided in the absorption liquid supply line 82.

[0065] In the solid-liquid separation device 80, the solid particles of calcium carbonate separated from the reaction product in the third reactor 76 are dried by a drying device 84 such as a conveyor type after being discharged from the solid-liquid separation device 80. The dried solid particles of calcium carbonate are stored in the storage section 86. The solid particles of calcium carbonate in the storage section 86 are pneumatically conveyed to the filter 64 through the conveyance line 88 by the conveyance gas G5. The individual particles of calcium carbonate separated from the conveyance gas G5 by the filter 64 are received by the storage hopper 24. Further, as already described, the solid particles of calcium carbonate in the storage hopper 24 are supplied to the first reactor 16 through the first raw material supply line 19.

[0066] In the exemplary embodiment shown in FIG. 2, the above-described third supply line 106 for supplying calcium carbonate from the third reaction section 14 to the first reaction section 10 through the first inlet port 18 includes the above-described conveyance line 88.

[0067] In the exemplary embodiment shown in FIG. 2, the above-described fourth supply line 108 for supplying calcium hydroxide generated in the first reaction section 10 to the third reaction section 14 includes the above-described conveyance line 46.

[0068] In the exemplary embodiment shown in FIG. 2, a drying device 58 for drying the solid particles of calcium carbonate generated in the second reaction section 12 and a drying device 84 for drying the solid particles of calcium carbonate generated in the third reaction section 14 are provided separately. In other embodiments, the same drying device may be used to dry both the solid particles of calcium carbonate generated in the second reaction section 12 and the solid particles of calcium carbonate generated in the third reaction section 14. Further, the dried calcium carbonate may be conveyed to the filter 64 from the drying device through a common conveyance line.

[0069] In the pulp manufacturing facility 100, in the recovery boiler 6 for burning the black liquor discharged in the cooking process, carbon dioxide is generated by the combustion of the black liquor. In this regard, according to the above-described embodiment, in the third reaction unit 14, carbon dioxide discharged from the recovery boiler 6 or the like is reacted with calcium hydroxide to produce calcium carbonate, so that carbon dioxide discharged to the outside of the system can be reduced. Further, since the calcium carbonate generated in the third reaction unit 14 is supplied to the first reaction unit 10, carbon dioxide discharged from the recovery boiler 6 or the like can be effectively utilized to convert calcium carbonate into calcium hydroxide that can be used in the causticizing process.

[0070] Further, in the above-described embodiment, since the calcium hydroxide generated in the first reaction unit 10 is supplied to the third reaction unit 14, in the third reaction unit 14, the calcium hydroxide and carbon dioxide can be reacted to produce calcium carbonate. Therefore, carbon dioxide discharged to the outside of the system can be reduced by using the calcium hydroxide generated in the first reaction unit 10.

[0071] In some embodiments, for example, as shown in FIG. 3, the reaction apparatus 1 includes a carbon dioxide recovery unit 110 for recovering carbon dioxide in the exhaust gas from the recovery boiler 6.

[0072] As shown in FIG. 3, the carbon dioxide recovery unit 110 includes an absorption tower 112 configured to supply the exhaust gas from the recovery boiler 6 (see FIG. 1) and absorb the carbon dioxide contained in the exhaust gas into an absorption liquid, and a regeneration tower 120 for regenerating the absorption liquid from the absorption tower 112. The absorption liquid may include an aqueous solution of an alkanolamine such as monoethanolamine or diethanolamine, or an aqueous solution of a basic substance other than an amine such as sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0073] The absorption tower 112 is configured such that the exhaust gas containing carbon dioxide from the recovery boiler 6 is supplied thereto via the exhaust gas line 68. The absorption tower 112 has an absorption section 114 formed of, for example, a packed bed, and the absorption liquid is supplied to the absorption section 114 from above.

[0074] The exhaust gas flowing into the absorption tower 112 via the exhaust gas line 68 flows upward in the absorption tower 112 from the bottom side of the tower of the absorption tower 112 and flows into the absorption section 114. In the absorption section 114, the exhaust gas and the absorption liquid supplied from above the absorption section 114 come into countercurrent contact, so that the carbon dioxide in the exhaust gas is absorbed by the absorption liquid.

[0075] The exhaust gas after the carbon dioxide gas has been removed by contact with the absorption liquid in the absorption section 114 is discharged to the outside from the top of the absorption tower 112. On the other hand, the absorption liquid that has absorbed the carbon dioxide in the exhaust gas in the absorption section 114 descends to the bottom 116 of the tower of the absorption tower 112 and is stored in the bottom 116 of the tower. The absorption liquid stored in the bottom 116 of the absorption tower 112 is a rich liquid having a higher carbon dioxide concentration than the absorption liquid stored in the bottom 124 of the regeneration tower 120 described later. This rich liquid is supplied from the absorption tower 112 to the regeneration tower 120 via the rich liquid line 118 by a pump provided in the rich liquid line 118.

[0076] The regeneration tower 120 includes a release section 122 that releases carbon dioxide gas from the rich liquid. The release section 122 has a packing material, and the rich liquid from the rich liquid line 118 is supplied from above. The rich liquid is heated by the steam supplied from the regeneration heater (reboiler) 128 in the release section 122 to release carbon dioxide gas, and becomes a lean liquid having a relatively low carbon dioxide content.

[0077] The lean liquid that has released carbon dioxide gas in the release section 122 descends inside the regeneration tower 120 and is stored in the bottom section 124 of the regeneration tower 120. This lean liquid is led through the reboiler line 126 to a regeneration heater (reboiler) 128 provided on the reboiler line 126. In the regeneration heater 128, at least a part of the lean liquid undergoes a phase change to saturated vapor by heat exchange with a heating medium (such as steam, etc.), and is led to the bottom section 124 of the regeneration tower 120. The saturated vapor thus generated by the regeneration heater 128 rises inside the regeneration tower 120 toward the release section 122 and is used as a heat source for heating the rich liquid in the release section 122.

[0078] The lean absorption liquid stored in the bottom section 124 of the regeneration tower 120 is withdrawn from the bottom section 124 of the regeneration tower 120 and supplied, via the lean liquid line 130, to the absorption section 114 of the absorption tower 112 by a feed pump provided on the lean liquid line 130, and is reused as the absorption liquid described above.

[0079] The carbon dioxide recovery section 110 may be provided with a heat exchanger 132 for heat-exchanging the rich liquid flowing through the rich liquid line 118 and the lean liquid flowing through the lean liquid line 130. By heating the rich liquid through heat exchange with the relatively high-temperature lean liquid, the regeneration of the absorption liquid in the regeneration tower 120 can be promoted.

[0080] The carbon dioxide gas released from the rich liquid in the release section 122 of the regeneration tower 120 is released from the top of the regeneration tower 120 and led to the carbon dioxide gas line 134. In the exemplary embodiment shown in FIG. 3, the carbon dioxide gas released from the top of the regeneration tower 120 is supplied to the fuel synthesis section 34 via the carbon dioxide gas line 134.

[0081] The fuel synthesis section 34 shown in FIG. 3 is configured to perform fuel synthesis using carbon monoxide discharged from the first reaction section 10, carbon dioxide recovered in the carbon dioxide recovery section 110, and hydrogen. In the fuel synthesis section 34, a carbon-containing fuel such as methanol or methane can be synthesized using carbon dioxide and hydrogen.

[0082] According to the above embodiment, carbon monoxide (i.e., carbon monoxide discharged from the first reaction unit 10) and carbon dioxide from the carbon dioxide recovery unit 110 discharged in the process of recycling calcium carbonate discharged in the causticization process are reacted with hydrogen to generate fuel. Therefore, while reducing the amount of carbon dioxide emissions, calcium carbonate discharged in the causticization process can be efficiently recycled and reused in the causticization process, and carbon monoxide generated in the recycling process and carbon dioxide from the carbon dioxide recovery unit 110 can be effectively utilized as fuel.

[0083] The content described in each of the above embodiments is understood as follows, for example.

[0084] [1] The reaction apparatus (1) according to at least one embodiment of the present invention includes a first reaction unit (10) for generating carbon monoxide and calcium hydroxide from calcium carbonate and hydrogen, wherein the first reaction unit includes a first reactor (16) for reacting the calcium carbonate and the hydrogen to generate the carbon monoxide and the calcium hydroxide, a first inlet port (18) for supplying the calcium carbonate to the first reactor, a second inlet port (20) for supplying the hydrogen to the first reactor, and an outlet port (22) for discharging a reaction product containing the carbon monoxide and the calcium hydroxide from the first reactor, and is configured such that calcium carbonate from the second reaction unit (12) for converting sodium carbonate into sodium hydroxide is supplied to the first reaction unit through the first inlet port, and the calcium hydroxide generated in the first reaction unit is supplied to the second reaction unit through the outlet port.

[0085] ​In the configuration of [1] above, calcium carbonate from the second reaction section for carrying out the reaction of converting sodium carbonate into sodium hydroxide (i.e., for carrying out the causticization process) is supplied to the first reaction section, and calcium hydroxide generated by the reaction of calcium carbonate and hydrogen in the first reaction section is supplied to the second reaction section. Therefore, in the second reaction section, by reacting calcium hydroxide from the first reaction section with sodium carbonate, sodium hydroxide can be efficiently obtained by the reaction of the following formula (B) without going through the reaction of the following formula (A) (i.e., the reaction of obtaining calcium hydroxide from calcium oxide). CaO + H2O → Ca(OH)2…(A) Na2CO3+ Ca(OH)2→ 2NaOH + CaCO3…(B) Further, in the first reaction section, in the first reactor, calcium carbonate and hydrogen are reacted by the reaction of the following formula (D) to generate carbon monoxide and calcium hydroxide, so carbon dioxide is not generated in the process of obtaining calcium hydroxide from calcium carbonate. CaCO3+ H2→ CO + Ca(OH)2…(D) Therefore, according to the configuration of [1] above, while reducing the carbon dioxide emission amount, the calcium carbonate discharged in the causticization process can be efficiently recycled and reused in the causticization process (the above formula (B)).

[0086] Also, in the configuration of [1] above, carbon monoxide is generated by the reaction of the following formula (D) in the first reactor, so this carbon monoxide can also be effectively utilized as fuel.

[0087] [2] In some embodiments, in the configuration of [1] above, the reaction device a first supply line (102) for supplying the calcium carbonate from the second reaction section to the first reaction section through the first inlet port, a second supply line (104) for supplying the calcium hydroxide from the outlet port of the first reaction section to the second reaction section, is provided.

[0088] According to the configuration of [2] above, calcium carbonate from the second reaction section is supplied to the first reaction section via the first supply line, and calcium hydroxide from the first reaction section is supplied to the second reaction section via the second supply line. Therefore, as described in [1] above, while reducing the carbon dioxide emission amount, the calcium carbonate discharged in the causticization process can be efficiently recycled and reused in the causticization process (the above formula (B)).

[0089] [3] In some embodiments, in the configuration of [1] or [2] above, the reaction apparatus includes the second reaction section (12) for converting sodium carbonate into sodium hydroxide, and the second reaction section is configured to react sodium carbonate contained in the green liquor with calcium hydroxide to produce sodium hydroxide and calcium carbonate.

[0090] In a pulp manufacturing facility, a recovery boiler for burning the black liquor discharged in the cooking process may be used. The combustion residue (smelt) generated in the recovery boiler is dissolved and made into green liquor (a solution containing sodium carbonate), and is supplied to the causticization process. According to the configuration of [3] above, calcium carbonate from the second reaction section for performing the reaction of converting sodium carbonate contained in the green liquor into sodium hydroxide (that is, for performing the causticization process) is supplied to the first reaction section, and calcium hydroxide generated by the reaction of calcium carbonate and hydrogen in the first reaction section is supplied to the second reaction section. Therefore, as described in [1] above, while reducing the carbon dioxide emission amount, the calcium carbonate discharged in the causticization process can be efficiently recycled and reused in the causticization process (the above formula (B)).

[0091] [4] In some embodiments, in any of the configurations of [1] to [3] above, the reaction apparatus includes a third reaction section (14) for reacting carbon dioxide with calcium hydroxide to produce calcium carbonate, A third supply line (106) for supplying the calcium carbonate from the third reaction section to the first reaction section via the first inlet port is provided.

[0092] In a pulp manufacturing facility, in a recovery boiler for burning black liquor discharged in a cooking process, carbon dioxide is generated by the combustion of black liquor. According to the configuration of [4] above, in the third reaction section, carbon dioxide discharged from a recovery boiler or the like and calcium hydroxide are reacted to produce calcium carbonate, so that carbon dioxide discharged to the outside of the system can be reduced. Further, since the calcium carbonate generated in the third reaction section is supplied to the first reaction section, carbon dioxide discharged from a recovery boiler or the like can be effectively utilized to convert calcium carbonate into calcium hydroxide that can be used in a causticizing process.

[0093] [5] In some embodiments, in the configuration of [4] above, the reaction apparatus comprises a fourth supply line (108) for supplying the calcium hydroxide from the outlet port of the first reaction section to the third reaction section.

[0094] According to the configuration of [5] above, since the calcium hydroxide generated in the first reaction section is supplied to the third reaction section, calcium carbonate can be generated by reacting the calcium hydroxide and carbon dioxide in the third reaction section, so that carbon dioxide discharged to the outside of the system can be reduced by using the calcium hydroxide generated in the first reaction section 10.

[0095] [6] In some embodiments, in the configuration of [4] or [5] above, the reaction apparatus comprises an exhaust gas line (68) for supplying exhaust gas from a recovery boiler (6) for burning black liquor to the third reaction section, and the third reaction section is configured to generate calcium carbonate using carbon dioxide contained in the exhaust gas from the recovery boiler as a raw material.

[0096] According to the configuration of [6] above, in the third reaction section, carbon dioxide contained in the exhaust gas from the recovery boiler is reacted with calcium hydroxide to produce calcium carbonate, so that carbon dioxide discharged to the outside of the system can be reduced. Further, since the calcium carbonate generated in the third reaction section is supplied to the first reaction section, carbon dioxide contained in the exhaust gas from the recovery boiler can be effectively utilized to convert calcium carbonate into calcium hydroxide that can be used in the causticization process.

[0097] [7] In some embodiments, in any of the configurations of [1] to [6] above, the reaction apparatus includes a fuel synthesis section (34) configured to perform fuel synthesis using the carbon monoxide discharged from the first reactor and hydrogen.

[0098] In the configuration of [7] above, carbon monoxide discharged in the process of recycling calcium carbonate discharged in the causticization process (that is, carbon monoxide discharged from the first reactor) is reacted with hydrogen to generate fuel. Therefore, according to the configuration of [7] above, while reducing the carbon dioxide emission amount, calcium carbonate discharged in the causticization process can be efficiently recycled and reused in the causticization process, and carbon monoxide generated in the recycling process can be effectively utilized as fuel.

[0099] [8] In some embodiments, in any of the configurations of [1] to [3] above, the reaction apparatus includes a carbon dioxide recovery section (110) including an absorption tower (112) configured to absorb carbon dioxide in the exhaust gas from a recovery boiler (6) for burning black liquor into an absorption liquid, and a regeneration tower (120) for regenerating the absorption liquid from the absorption tower, and a fuel synthesis section (34) configured to perform fuel synthesis using the carbon monoxide discharged from the first reactor, the carbon dioxide from the carbon dioxide recovery section, and hydrogen. is provided.

[0100] According to the configuration of [8] above, carbon monoxide (i.e., carbon monoxide discharged from the first reactor) and carbon dioxide from the carbon dioxide recovery unit, which are discharged in the process of recycling calcium carbonate discharged in the causticization process, are reacted with hydrogen to produce fuel. Therefore, according to the configuration of [8] above, while reducing the amount of carbon dioxide emissions, calcium carbonate discharged in the causticization process can be efficiently recycled and reused in the causticization process, and carbon monoxide generated in the recycling process and carbon dioxide from the carbon dioxide recovery unit can be effectively utilized as fuel.

[0101] [9] The pulp manufacturing facility (100) according to at least one embodiment of the present invention the reactor according to any one of [1] to [8] above, and a digester (2) configured to digest wood using the sodium hydroxide from the second reaction section. is provided.

[0102] In the configuration of [9] above, calcium carbonate from the second reaction section for performing the reaction of converting sodium carbonate to sodium hydroxide (i.e., for performing the causticization process) is supplied to the first reaction section, and calcium hydroxide generated by the reaction of calcium carbonate and hydrogen in the first reaction section is supplied to the second reaction section. Therefore, in the second reaction section, by reacting calcium hydroxide from the first reaction section with sodium carbonate, the reaction of formula (B) can efficiently obtain sodium hydroxide without going through the reaction of formula (A) (i.e., the reaction of obtaining calcium hydroxide from calcium oxide). Also, in the first reaction section, in the first reactor, by the reaction of formula (D), calcium carbonate and hydrogen are reacted to generate carbon monoxide and calcium hydroxide, so carbon dioxide is not generated in the process of obtaining calcium hydroxide from calcium carbonate. Therefore, according to the configuration of [9] above, while reducing the amount of carbon dioxide emissions, calcium carbonate discharged in the causticization process can be efficiently recycled and reused in the causticization process (formula (B) above).

[0103] In addition, in the configuration of [9] above, since carbon monoxide is generated by the reaction of the above formula (D) in the first reactor, this carbon monoxide can also be effectively utilized as fuel.

[0104]

[10] In some embodiments, in the configuration of [9] above, the pulp manufacturing facility includes a recovery boiler (6) configured to burn the black liquor discharged from the digester, and the second reaction section is configured to react sodium carbonate contained in the green liquor containing the smelt discharged from the recovery boiler with calcium hydroxide to produce sodium hydroxide and calcium carbonate.

[0105] According to the configuration of

[10] above, calcium carbonate from the second reaction section for performing a causticization step of treating the green liquor containing the smelt discharged from the recovery boiler that burns the black liquor discharged from the digester is supplied to the first reaction section, and calcium hydroxide generated by the reaction of calcium carbonate and hydrogen in the first reaction section is supplied to the second reaction section. Therefore, as described in [9] above, while reducing the carbon dioxide emission amount, the calcium carbonate discharged in the causticization step can be efficiently recycled and reused in the causticization step.

[0106]

[11] The reaction method according to at least one embodiment of the present invention includes a step of supplying calcium carbonate from a second reaction section (12) for converting sodium carbonate to sodium hydroxide to a first reaction section (10), a step of reacting the calcium carbonate and hydrogen in the first reaction section to produce carbon monoxide and calcium hydroxide, and a step of supplying the calcium hydroxide generated in the first reaction section to the second reaction section.

[0107] In the method of

[11] above, calcium carbonate from the second reaction part for carrying out the reaction of converting sodium carbonate into sodium hydroxide (i.e., for carrying out the causticization step) is supplied to the first reaction part, and calcium hydroxide produced by the reaction of calcium carbonate and hydrogen in the first reaction part is supplied to the second reaction part. Therefore, in the second reaction part, by reacting calcium hydroxide from the first reaction part with sodium carbonate, sodium hydroxide can be efficiently obtained by the reaction of the above formula (B) without going through the reaction of the above formula (A) (i.e., the reaction of obtaining calcium hydroxide from calcium oxide). Also, in the first reaction part, since carbon monoxide and calcium hydroxide are produced by reacting calcium carbonate and hydrogen by the reaction of the above formula (D), carbon dioxide is not generated in the process of obtaining calcium hydroxide from calcium carbonate. Therefore, according to the method of

[11] above, while reducing the carbon dioxide emission amount, the calcium carbonate discharged in the causticization step can be efficiently recycled and reused in the causticization step (the above formula (B)).

[0108] Also, in the method of

[11] above, since carbon monoxide is produced by the reaction of the above formula (D), this carbon monoxide can also be effectively utilized as fuel.

[0109]

[12] The pulp manufacturing method according to at least one embodiment of the present invention includes a step of performing the reaction method described in

[11] above, and a step of digesting wood using the sodium hydroxide from the second reaction part. It is provided with.

[0110] In the method of

[12] above, calcium carbonate from the second reaction section for carrying out the reaction of converting sodium carbonate into sodium hydroxide (i.e., for carrying out the causticization step) is supplied to the first reaction section, and calcium hydroxide generated by the reaction of calcium carbonate and hydrogen in the first reaction section is supplied to the second reaction section. Therefore, in the second reaction section, by reacting calcium hydroxide from the first reaction section with sodium carbonate, sodium hydroxide can be efficiently obtained by the reaction of formula (B) without going through the reaction of formula (A) (i.e., the reaction of obtaining calcium hydroxide from calcium oxide). Further, in the first reaction section, by the reaction of formula (D), calcium carbonate and hydrogen are reacted to generate carbon monoxide and calcium hydroxide, so carbon dioxide is not generated in the process of obtaining calcium hydroxide from calcium carbonate. Therefore, according to the method of

[12] above, while reducing the carbon dioxide emission amount, the calcium carbonate discharged in the causticization step can be efficiently recycled and reused in the causticization step (formula (B) above).

[0111] Also, in the method of

[12] above, since carbon monoxide is generated by the reaction of formula (D), this carbon monoxide can also be effectively utilized as fuel.

[0112] As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and also includes forms obtained by modifying the above-described embodiments and forms obtained by appropriately combining these forms.

[0113] In this specification, expressions representing relative or absolute arrangements such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric", or "coaxial" not only strictly represent such arrangements, but also represent states of being relatively displaced with tolerances or at angles and distances such that the same function can be obtained. For example, expressions indicating that things such as "identical", "equal", and "homogeneous" are in an equal state shall represent not only a strictly equal state but also a state in which there is a tolerance or a difference to the extent that the same function can be obtained. Also, in this specification, expressions representing shapes such as a rectangular shape or a cylindrical shape shall represent not only the shapes of a rectangular shape or a cylindrical shape in a geometrically strict sense but also shapes including concave and convex portions, chamfered portions, etc. within the range where the same effect can be obtained. Also, in this specification, the expressions "comprises", "includes", or "has" for a component are not exclusive expressions excluding the existence of other components.

Explanation of Reference Signs

[0114] 1 Reactor 2 Digester 4 Evaporator 6 Recovery Boiler 8 Causticizing Section 10 First Reaction Section 12 Second Reaction Section 14 Third Reaction Section 16 First Reactor 17 Catalyst 18 First Inlet Port 19 First Raw Material Supply Line 20 Second Inlet Port 21 Second Raw Material Supply Line 22 Outlet Port 23 Discharge Line 24 Storage Hopper 25 On - Off Valve 26 Pressure Hopper 28 Hydrogen Supply Source 30 Heating Section 31 Heat Exchanger 32 Heat Exchanger 34 Fuel Synthesis Section 36 Solid - Gas Separation Device 37 CO Gas Line 38 Storage Section 40 Second Reactor 42 Green Liquor Supply Line 44 Supply Line 45 Pump 46 Conveyor Line 48 Filter 50 Storage Hopper 52 Solution Tank 53 Discharge Line 54 Solid-Liquid Separation Device 55 Pump 56 Solution Line 58 Drying Device 60 Storage Section 62 Conveyor Line 64 Filter 66 Absorption Tower 68 Exhaust Gas Line 70 Absorbent Supply Section 74 Solution Supply Line 75 Pump 76 Third Reactor 78 Discharge Line 79 Pump 80 Solid-Liquid Separation Device 82 Absorbent Supply Line 83 Pump 84 Drying Device 86 Storage Section 88 Conveyor Line 100 Pulp Manufacturing Equipment 102 First Supply Line 104 Second Supply Line 106 Third Supply Line 108 Fourth Supply Line 110 Carbon Dioxide Recovery Section 112 Absorption Tower 114 Absorption Section 116 Tower Bottom 118 Rich Liquid Line 120 Regeneration Tower 122 Discharge Section 124 Tower Bottom 126 Reboiler Line 128 Regeneration Heater 130 Lean Liquid Line 132 Heat Exchanger 134 Carbon Dioxide Gas Line G1 Conveying Gas G2 Pressurized Gas G3 Transfer Gas G4 Transfer Gas G5 Transfer Gas HM Heat Medium

Claims

1. A first reaction section for producing carbon monoxide and calcium hydroxide from calcium carbonate and hydrogen, The first reaction section includes a first reactor for reacting the calcium carbonate and the hydrogen to produce the carbon monoxide and the calcium hydroxide; a first inlet port for supplying the calcium carbonate to the first reactor; a second inlet port for supplying the hydrogen to the first reactor; an outlet port for discharging a reaction product containing the carbon monoxide and the calcium hydroxide from the first reactor; and calcium carbonate from a second reaction section for converting sodium carbonate to sodium hydroxide is supplied to the first reaction section through the first inlet port, and the calcium hydroxide produced in the first reaction section is supplied to the second reaction section through the outlet port, a reaction apparatus.

2. a first supply line for supplying the calcium carbonate from the second reaction section to the first reaction section through the first inlet port; a second supply line for supplying the calcium hydroxide from the outlet port of the first reaction section to the second reaction section; and the reaction apparatus according to claim 1.

3. a second reaction section for converting sodium carbonate to sodium hydroxide, The second reaction section is configured to react sodium carbonate contained in green liquor with calcium hydroxide to produce sodium hydroxide and calcium carbonate the reaction apparatus according to claim 1 or 2.

4. a third reaction section for reacting carbon dioxide with calcium hydroxide to produce calcium carbonate; a third supply line for supplying the calcium carbonate from the third reaction section to the first reaction section through the first inlet port; and the reaction apparatus according to claim 1 or 2.

5. The reaction apparatus according to claim 4, further comprising a fourth supply line for supplying the calcium hydroxide from the outlet port of the first reaction section to the third reaction section.

6. The reaction apparatus according to claim 4, further comprising an exhaust gas line for supplying exhaust gas from a recovery boiler for burning black liquor to the third reaction section, The third reaction section is configured to produce calcium carbonate using carbon dioxide contained in the exhaust gas from the recovery boiler as a raw material.

7. The reaction apparatus according to claim 4. ​ A fuel synthesis unit configured to perform fuel synthesis using the carbon monoxide and hydrogen discharged from the first reactor is provided. The reaction apparatus according to claim 1 or 2.

8. An absorption tower configured to absorb carbon dioxide in the exhaust gas from a recovery boiler for burning black liquor into an absorption liquid, and a regeneration tower for regenerating the absorption liquid from the absorption tower, and a carbon dioxide recovery unit including the same. A fuel synthesis unit configured to perform fuel synthesis using the carbon monoxide discharged from the first reactor, the carbon dioxide from the carbon dioxide recovery unit, and hydrogen. The reaction apparatus according to claim 1 or 2, comprising the same.

9. The reaction apparatus according to claim 1 or 2, and A digester configured to digest wood using the sodium hydroxide from the second reaction section. A pulp manufacturing facility comprising the same.

10. A recovery boiler configured to burn the black liquor discharged from the digester is provided. The second reaction section is configured to react sodium carbonate contained in green liquor containing the smelt discharged from the recovery boiler with calcium hydroxide to produce sodium hydroxide and calcium carbonate. The pulp manufacturing facility according to claim 9.

11. Supplying calcium carbonate from a second reaction section for converting sodium carbonate to sodium hydroxide to a first reaction section; Reacting the calcium carbonate and hydrogen in the first reaction section to produce carbon monoxide and calcium hydroxide; Supplying the calcium hydroxide produced in the first reaction section to the second reaction section. Comprising A reaction method.

12. Performing the reaction method according to claim 11; Digesting wood using the sodium hydroxide from the second reaction section. A pulp manufacturing method comprising the same.

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