JP2024039390A - Co2 recovery system of cement manufacturing plant, and co2 recovery method of cement manufacturing plant - Google Patents

Abstract

To provide a CO2 recovery system of a cement manufacturing plant which can efficiently recover CO2 of a raw material source and CO2 of a fuel source.SOLUTION: A CO2 recovery system of a cement manufacturing plant includes: a combustion exhaust gas pipe 30 which has a kiln 10 for cement manufacture and an indirect heating type calcining furnace 20, and allows exhaust gas containing combustion exhaust gas discharged from the indirect heating type calcining furnace 20 to flow therein; an exhaust gas heat exchanger 40 having a suction port connected to the combustion exhaust gas pipe 30, and an exhaust port; a reaction device 50 which has an exhaust gas introduction port connected to the exhaust port of the exhaust gas heat exchanger 40, a calcium oxide introduction port, a calcium carbonate take-out port and an exhaust gas discharge port, brings the exhaust gas introduced from the gas introduction port into contact with the calcium oxide introduced from the calcium oxide introduction port, thereby reacts CO2 in the exhaust gas with the calcium oxide and generates calcium carbonate; and a conveyance device for conveying the calcium carbonate taken out of the calcium carbonate take-out port of the reaction device 50 to a raw material introduction port of the indirect heating type calcining furnace 20.SELECTED DRAWING: Figure 1

Description

The present invention relates to a CO ₂ recovery system for cement manufacturing equipment and a CO ₂ recovery method for cement manufacturing equipment.

Cement manufacturing equipment generates a large amount of CO ₂ during cement manufacturing. The CO ₂ generated during the production of cement includes CO ₂ originating from raw materials and CO ₂ originating from fuel. CO ₂ originating from raw materials is CO ₂ generated when calcium carbonate (limestone), which is the main component of cement raw materials, thermally decomposes to produce calcium oxide (quicklime). Fuel-derived CO ₂ is CO ₂ in the exhaust gas of combustion gas used as a heat source when firing cement raw materials.

In order to reduce CO ₂ emissions from cement manufacturing equipment, systems are being considered to recover CO ₂ generated during cement manufacturing. As a system that can recover raw material-originated _CO2 with high efficiency, the cement raw material is heated by mixing the cement raw material with a heat medium heated to above the thermal decomposition temperature of calcium carbonate using combustion gas in a mixing calcination furnace. A system for recovering raw material-originated CO ₂ generated by calcining is being considered (Patent Documents 1 and 2). Patent Document 1 describes that exhaust gas (combustion exhaust gas) of combustion gas used to heat a heat medium and cement raw material are supplied to a preheater, and the cement raw material is preheated with the combustion exhaust gas. Furthermore, Patent Document 2 discloses that after cooling a part of the cement raw material after calcining in a heat exchanger, the cement raw material is returned to the preheater, and the cement raw material is brought into contact with combustion exhaust gas, and the cement raw material is combusted into calcium oxide in the cement raw material. It is described that CO ₂ originating from fuel in exhaust gas is absorbed.

Japanese Patent Application Publication No. 2009-292715 JP2011-088760A

In the cement manufacturing equipment described in Patent Document 1, since the cement raw material is preheated with combustion exhaust gas, the heat source in the cement manufacturing equipment can be effectively utilized. However, since the combustion exhaust gas has a high temperature, when preheating the cement raw material with the combustion exhaust gas, a part of the calcium carbonate may be thermally decomposed and CO ₂ originating from the raw material may be generated in the preheater. Furthermore, in the cement manufacturing equipment described in Patent Document 2, the temperature of the combustion exhaust gas further increases due to the reaction heat generated by the reaction between calcium oxide and CO ₂ in the combustion exhaust gas, and calcium oxide and CO ₂ There was a risk that the reaction with calcium oxide would be suppressed, making it difficult for calcium oxide to absorb CO ₂ originating from the fuel.

This invention was made in view of the above-mentioned circumstances, and includes a CO ₂ recovery system for cement manufacturing equipment and a cement manufacturing equipment system that can efficiently recover CO ₂ originating from raw materials and CO ₂ originating from fuel. The objective is to provide a CO ₂ recovery method.

In order to solve the above problems, a CO ₂ recovery system for cement manufacturing equipment according to aspect 1 of the present invention includes a cement manufacturing kiln, a raw material inlet, a calcined product outlet, and a CO ₂ outlet. , CO ₂ recovery in a cement manufacturing facility that has an indirect heating type calciner that indirectly calcinates the cement raw material introduced from the raw material inlet using combustion gas to produce a cement raw material calcined product and CO ₂ . A system, an exhaust gas heat exchanger having a combustion exhaust gas pipe through which exhaust gas including combustion exhaust gas discharged from the indirect heating calciner flows, an intake port connected to the combustion exhaust gas pipe, and an exhaust port; It has an exhaust gas inlet connected to the exhaust port of the exhaust gas heat exchanger, a calcium oxide inlet, a calcium carbonate outlet, and a gas outlet, and the exhaust gas introduced from the exhaust gas inlet and the calcium oxide A reaction device for reacting CO ₂ in the combustion exhaust gas with the calcium oxide to produce calcium carbonate by bringing the calcium oxide introduced through the inlet into contact with the calcium oxide, and removing the calcium carbonate from the calcium carbonate outlet of the reaction device. and a conveyance device that conveys the calcium carbonate thus obtained to the raw material inlet of the indirect heating type calcining furnace.

According to the CO ₂ recovery system for cement manufacturing equipment of aspect 1 of the present invention having such a configuration, the cement raw material is indirectly calcined using combustion gas in the indirect heating type calcining furnace to produce the cement raw material. Since the calcined material and CO ₂ are generated, a high concentration of CO ₂ can be generated in the indirect heating type calcination furnace. In addition, in the reaction device, the CO ₂ in the combustion exhaust gas and calcium oxide are reacted to generate calcium carbonate, and the generated calcium carbonate is supplied to the indirect heating type calciner by the conveyance device, so that the combustion exhaust gas The CO ₂ inside can be recovered. Furthermore, after reducing the temperature of the combustion exhaust gas using an exhaust gas heat exchanger, calcium oxide and CO ₂ are reacted in the reaction device, so that the reaction between CO ₂ and calcium oxide in the reaction device is prevented. promoted. Therefore, the efficiency of collecting CO ₂ in the combustion exhaust gas is improved. Therefore, according to the CO ₂ recovery system for cement manufacturing equipment of the present invention, CO ₂ originating from raw materials and CO ₂ originating from fuel can be efficiently recovered. Furthermore, the amount of combustion gas used can be reduced by using the heat generated by the reaction between calcium oxide and CO ₂ in the combustion exhaust gas for preheating cement raw materials.

A second aspect of the present invention is a CO ₂ recovery system for the cement manufacturing equipment according to aspect 1, which includes a pipe for conveying the kiln exhaust gas discharged from the cement manufacturing kiln to the intake port of the exhaust gas heat exchanger. has been done.
According to the CO ₂ recovery system for cement production equipment according to aspect 2 of the present invention, CO ₂ in the combustion exhaust gas discharged from the indirect heating type calciner and CO 2 in the kiln exhaust gas discharged from the cement production kiln are ₂ can be recovered. Further, the amount of combustion gas used can be further reduced by using the reaction heat generated by reacting CO ₂ in the kiln exhaust gas with calcium oxide for preheating cement raw materials.

Aspect 3 of the present invention is the CO ₂ recovery system for cement manufacturing equipment according to aspect 1 or 2, wherein the cement raw material calcined product contains calcium oxide and is taken out from the calcined product outlet of the indirect heating type calciner. The cement raw material calcined product is configured to include a first conveyance path for conveying the calcined cement raw material to the cement manufacturing kiln, and a second conveyance path for conveying the calcined cement raw material to the calcium oxide inlet of the reaction device.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 3 of the present invention, CO ₂ in the combustion exhaust gas can be recovered using the calcined cement raw material. Moreover, it becomes easy to adjust the amount of calcium oxide brought into contact with CO ₂ in the combustion exhaust gas.

According to a fourth aspect of the present invention, in the CO ₂ recovery system for the cement manufacturing equipment according to the third aspect, a cooler is disposed in the second conveyance path.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 4 of the present invention, it is possible to lower the temperature of calcium oxide that is brought into contact with the combustion exhaust gas discharged from the indirect heating type calciner, so that the temperature of the calcium oxide in the combustion exhaust gas can be lowered. Even if reaction heat is generated by reacting CO ₂ and calcium oxide, the temperature of the produced calcium carbonate can be maintained at a predetermined temperature. Therefore, the temperature of the combustion exhaust gas becomes difficult to rise, and CO ₂ in the combustion exhaust gas can be recovered with higher efficiency.

Aspect 5 of the present invention is the CO ₂ recovery system of the cement manufacturing equipment according to aspect 3 or 4, in which the amount of the calcined cement raw material to be conveyed to the cement manufacturing kiln and the calcium oxide inlet of the reaction device are controlled. The structure includes a calcium oxide amount control device that controls the amount of the calcined cement raw material to be transported.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 5 of the present invention, it is possible to adjust the amount of calcium oxide to be transported to the reaction device, so that the amount of calcium oxide necessary for recovering the CO ₂ in the combustion exhaust gas can be adjusted. Calcium oxide can be fed to the reactor in an amount that is suitable for the reaction. Therefore, CO ₂ in the combustion exhaust gas can be recovered with even higher efficiency.

Aspect 6 of the present invention is the CO ₂ recovery system for cement manufacturing equipment according to aspect 5, in which the calcium oxide amount control device controls the CO ₂ concentration of the gas introduced from the exhaust gas inlet of the reaction device, and The amount of calcium oxide to be transported to the calcium oxide inlet of the reaction device is adjusted based on one or both of the CO ₂ concentrations of the gas exhausted from the gas exhaust port.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 6 of the present invention, the amount of calcium oxide required to recover CO ₂ in the combustion exhaust gas can be reliably supplied to the reaction device. Therefore, CO ₂ in the combustion gas can be recovered with even higher efficiency.

Aspect 7 of the present invention is the CO ₂ recovery system for cement manufacturing equipment according to aspect 5 or 6, in which the temperature of the gas exhausted from the gas extraction outlet of the reaction device, the calcium carbonate extracted from the calcium carbonate outlet The amount of calcium oxide to be transported to the calcium oxide inlet of the reaction device is adjusted based on one or both of the temperatures.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 7 of the present invention, the amount of calcium oxide required to recover CO ₂ in the combustion exhaust gas can be reliably supplied to the reaction device. Therefore, CO ₂ in the combustion gas can be recovered with even higher efficiency.

Aspect 8 of the present invention is the CO ₂ recovery system for cement manufacturing equipment according to aspect 7, in which the calcium oxide amount control device further controls the temperature of the gas introduced from the exhaust gas inlet of the reaction device, The amount of calcium oxide to be transported to the calcium oxide inlet of the reaction apparatus is adjusted based on one or both of the temperature of the calcium oxide introduced into the calcium inlet.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 8 of the present invention, the amount of calcium oxide required to recover CO ₂ in the combustion exhaust gas can be more reliably supplied to the reaction device. Therefore, CO ₂ in the combustion gas can be recovered with even higher efficiency.

Aspect 9 of the present invention is a CO ₂ recovery system for cement manufacturing equipment according to any one of aspects 1 to 8, in which the exhaust gas heat exchanger is configured to connect a cement raw material input port and a cement raw material input port to which cement is supplied from the cement raw material input port. A preheater including a solid-gas separator that separates a raw material and the combustion exhaust gas, the preheater having a cement raw material amount control device that controls the amount of cement raw material supplied from the cement raw material input port of the preheater. There is.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 9 of the present invention, since the cement raw material is preheated with the heat of the combustion exhaust gas, the amount of heat when indirectly heating the cement raw material, that is, the amount of combustion gas used is reduced. be able to. Therefore, the amount of CO ₂ generated from fuel can be reduced.

Aspect 10 of the present invention is a CO ₂ recovery system for cement manufacturing equipment according to any one of aspects 1 to 9, wherein the reaction device includes a cooling section.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 10 of the present invention, the reaction between CO ₂ and calcium oxide in the reaction device is promoted by lowering the temperature in the reaction device using the cooling section. Ru. Therefore, the recovery efficiency of CO ₂ in the combustion exhaust gas is improved.

Aspect 11 of the present invention is a CO ₂ recovery system for cement manufacturing equipment according to aspect 10, in which the cooling section is a boiler that generates water vapor by absorbing heat from water.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 11 of the present invention, the temperature inside the reaction device can be efficiently lowered.

A twelfth aspect of the present invention is a CO ₂ recovery system for the cement manufacturing equipment according to any one of the first to eleventh aspects, wherein the CO 2 recovery system includes a pressure reducing device that reduces the internal pressure of the indirectly heated calciner.
According to the CO ₂ recovery system for cement manufacturing equipment according to aspect 12 of the present invention, the thermal decomposition temperature of calcium carbonate in the indirectly heated calciner can be lowered by reducing the internal pressure of the indirectly heated calciner. I can do it. Thereby, the amount of heat when indirectly heating the cement raw material, that is, the amount of combustion gas used can be reduced. Therefore, the amount of CO ₂ generated from fuel can be reduced. Furthermore, the temperature of the combustion exhaust gas discharged from the indirect heating type calciner can be lowered, and generation of CO ₂ originating from the raw material in the exhaust gas heat exchanger can be suppressed.

According to a thirteenth aspect of the present invention, the CO ₂ recovery system for the cement manufacturing equipment according to any one of the first to twelfth aspects includes a pressurizing device that pressurizes the internal pressure of the reaction device.
According to the CO ₂ recovery system for cement production equipment according to aspect 13 of the present invention, the thermal decomposition temperature of calcium carbonate can be increased by increasing the internal pressure of the reaction device. Thereby, the reaction between CO ₂ in the combustion exhaust gas and calcium oxide is promoted, and the CO ₂ in the combustion exhaust gas can be recovered with even higher efficiency.

Aspect 14 of the present invention is a CO ₂ recovery system for the cement manufacturing equipment according to any one of aspects 1 to 13, in which CO ₂ generated in equipment other than the cement manufacturing kiln and the indirectly heated calciner is recovered. The reactor is configured to include piping for conveying the contained gas to the intake port of the exhaust gas heat exchanger or the exhaust gas inlet of the reaction device.
According to the CO ₂ recovery system for cement production equipment according to aspect 14 of the present invention, CO ₂ generated in other equipment other than the cement production kiln and indirect heating calciner can be efficiently recovered and released into the atmosphere. _CO2 released can be reduced.

A method for recovering CO ₂ from a cement production facility according to aspect 15 of the present invention is a cement production kiln, and a cement production kiln having an indirect heating type calcining furnace comprising a raw material inlet, a calcined product outlet, and a CO ₂ outlet. A CO ₂ recovery method for manufacturing equipment, wherein cement raw material introduced from the raw material inlet of the indirect heating type calciner is indirectly heated and calcined using combustion gas to produce a cement raw material calcined product. A CO ₂ recovery step in which CO ₂ is generated and the CO ₂ is recovered; and a cooling step in which the combustion exhaust gas discharged from the indirect heating calciner is introduced into an exhaust gas heat exchanger and cooled to 450° C. or below. a calcium carbonate generation step of causing the CO ₂ in the combustion exhaust gas to react with the calcium oxide to generate calcium carbonate by bringing the combustion exhaust gas cooled to 450° C. or lower into contact with calcium oxide; The method includes a calcium carbonate supplying step of supplying calcium to the raw material inlet of the indirect heating type calcining furnace.

According to the CO ₂ recovery method for cement manufacturing equipment of aspect 15 of the present invention having such a configuration, in the CO ₂ recovery process, cement raw materials are indirectly calcined using combustion gas to convert them into cement raw materials. Since the calcined material and CO ₂ are generated, a high concentration of CO ₂ can be generated in the indirect heating type calcination furnace. In addition, in the calcium carbonate production process, _CO2 in the combustion exhaust gas and calcium oxide are reacted to produce calcium carbonate, and in the calcium carbonate supply process, the produced calcium carbonate is transferred to an indirect heating calciner using a conveying device. CO ₂ in the combustion exhaust gas can be recovered. Furthermore, in the cooling process, the temperature of the combustion exhaust gas is reduced to 450°C or less using an exhaust gas heat exchanger, and then in the calcium carbonate generation process, CO ₂ in the combustion exhaust gas and calcium oxide are reacted. , the reaction between CO ₂ and calcium oxide is promoted. Therefore, the efficiency of collecting CO ₂ in the combustion exhaust gas is improved. Therefore, according to the CO ₂ recovery method for cement manufacturing equipment of aspect 13, CO ₂ originating from raw materials and CO ₂ originating from fuel can be efficiently recovered. Furthermore, by using the heat generated by the reaction between calcium oxide and _CO2 in combustion exhaust gas to preheat cement raw materials, the amount of heat (amount of combustion gas used) when indirectly heating cement raw materials can be reduced. be able to. Therefore, the amount of CO ₂ generated from fuel can be reduced.

Aspect 16 of the present invention is the CO ₂ recovery method for cement manufacturing equipment according to aspect 15, in which the combustion exhaust gas and the exhaust gas generated in the cement manufacturing kiln are combined with each other before introducing the combustion gas into the exhaust gas heat exchanger. The method may include a mixing step of mixing to generate a mixed exhaust gas, and may be configured to cool the mixed exhaust gas to 450° C. or lower in the cooling step.
According to the method for recovering CO ₂ from cement production equipment according to aspect 16 of the present invention, it is possible to recover CO ₂ in the exhaust gas of the cement production kiln together with CO ₂ in the combustion exhaust gas. In addition, by using the reaction heat generated by reacting CO ₂ in the exhaust gas of a cement manufacturing kiln with calcium oxide for preheating cement raw materials, we can use the amount of heat required to indirectly heat cement raw materials (combusted gas ) and the amount of combustion gas used in the cement manufacturing kiln. Therefore, the amount of CO ₂ generated from fuel can be reduced.

According to the present invention, it is possible to provide a CO ₂ recovery system for cement manufacturing equipment and a _{CO 2 recovery} method for cement manufacturing equipment that can efficiently recover CO 2 originating from raw materials and CO ₂ originating from fuel. Become.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram which shows the _CO2 recovery system of the cement manufacturing equipment based on 1st Embodiment of this invention. FIG. 2 is a schematic configuration diagram showing a CO ₂ recovery system for cement manufacturing equipment according to a second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A CO ₂ recovery system for cement manufacturing equipment and a CO ₂ recovery method for cement manufacturing equipment according to an embodiment of the present invention will be described below with reference to the drawings. It should be noted that each of the embodiments shown below will be specifically described in order to better understand the gist of the invention, and will not limit the invention unless otherwise specified. Furthermore, in order to make the features of the present invention easier to understand, the drawings used in the following explanation may show important parts enlarged for convenience, and the dimensional ratio of each component may be the same as the actual one. Not necessarily.

(First embodiment)
FIG. 1 is a schematic configuration diagram showing a CO ₂ recovery system for cement manufacturing equipment according to a first embodiment of the present invention. In addition, in FIG. 1, solid line arrows schematically represent the flow of substances, and dashed line arrows schematically represent the flow of gas.
As shown in FIG. 1, a CO ₂ recovery system 101 for cement manufacturing equipment includes a cement manufacturing kiln 10 and an indirect heating type calcining furnace 20.

The cement production kiln 10 includes a rotatable cylindrical furnace body 11 and a main burner 12 that heats the inside of the furnace body 11. The furnace body 11 has a cement raw material calcined product introduction section at one end and a cement clinker takeout section at the other end. The cement clinker extractor is connected to a clinker cooler 13. The clinker cooler 13 has a cooling device such as a cooling fan. The cement manufacturing kiln 10 generates cement clinker and CO ₂ by firing a cement raw material calcined product using a main burner 12 . The generated CO ₂ originating from the raw materials and the exhaust gas from the main burner 12 are taken out through the kiln exhaust gas pipe 14 . The clinker cooler 13 cools the cement clinker through heat exchange with air. High temperature air CG obtained when cement clinker is cooled is taken out from the clinker cooler 13.

The indirect heating type calcining furnace 20 has a raw material inlet at the lower part and a calcined product outlet at the upper part. The calcined product outlet is connected to the calcined product removal pipe 21. The indirect heating type calciner 20 also includes a combustion gas pipe 23 through which combustion gas flows. A combustion gas exhaust port of the combustion gas pipe 23 is connected to a combustion exhaust gas pipe 30 , and the other end of the combustion exhaust gas pipe 30 is connected to a solid-gas separator 31 . The solid-gas separator 31 is connected to the kiln exhaust gas pipe 14 and the exhaust gas heat exchanger 40. Exhaust gas heat exchanger 40 is connected to reactor 50 . The reactor 50 is connected to a reaction product gas heat exchanger 60.

The indirect heating type calcining furnace 20 heats and calcinates the cement raw material using the heat of the combustion gas flowing through the combustion gas pipe 23 to generate a cement raw material calcined product and CO ₂ .
As the cement raw material, for example, a mixed powder containing limestone (calcium carbonate) as the main component and clay components (SiO ₂ , Al ₂ O ₃ , Fe ₂ O ₃ ) can be used. By heating and calcining this cement raw material, part or all of the limestone in the cement raw material is thermally decomposed to generate a calcined cement raw material containing calcium oxide and _CO2 .

The calcined product extraction pipe 21 is a pipe for taking out the cement raw material calcined product and CO ₂ generated in the indirect heating type calcining furnace 20 to the outside. The calcined product removal pipe 21 is connected to a solid-gas separator 22 . The solid-gas separator 22 separates the cement raw material calcined product from CO ₂ . As the solid-gas separator 22, for example, a cyclone can be used. A gas outlet of the solid-gas separator 22 is connected to an inlet (piping 72a) of the CO ₂ heat exchanger 70. The cement raw material calcined product outlet of the solid-gas separator 22 is connected to the conveyance path A.

The CO ₂ heat exchanger 70 includes three solid-gas separators 71a, 71b, and 71c arranged in series in the vertical direction, and pipes 72a, 72b, and 72c that connect the solid-gas separators 71a, 71b, and 71c. have The uppermost solid-gas separator 71c is connected to an exhaust CO ₂ pipe 72d. A blower 73 is arranged in the exhaust CO ₂ pipe 72d. A cement raw material input port is arranged in a pipe 72c between the uppermost solid-gas separator 71c and the middle solid-gas separator 71b. The amount of cement raw material input is controlled by a cement raw material amount control device. The solid matter outlet of the solid-gas separator 71a at the lowest stage is connected to the conveyance path E. The conveyance path E is connected to a raw material inlet of the indirect heating type calcining furnace 20. For example, cyclones can be used as the solid-gas separators 71a, 71b, and 71c. The CO ₂ heat exchanger 70 acts as a preheater that preheats the cement raw material by bringing the cement raw material introduced from the cement raw material input port into contact with CO ₂ .

As the conveyance path A, a device used as a conveyance device for cement raw materials, such as a pipeline, can be used. The conveyance path A is connected to a calcium oxide amount control device 55. The calcium oxide amount control device 55 is connected to the first conveyance path A1 and the second conveyance path A2. The first conveyance path A1 is a conveyance path that conveys the calcined cement raw material to the cement manufacturing kiln 10. The second conveyance path A2 is a conveyance path that conveys the calcined cement raw material to the reaction device 50. The calcium oxide amount control device 55 controls the amount of calcined cement raw material to be transported to the cement production kiln 10 and the amount of calcined cement raw material to be transported to the calcium oxide inlet of the reaction device 50.

The calcium oxide amount control device 55 controls the CO ₂ concentration of the gas introduced from the gas inlet (reaction tube 51) of the reaction device 50 and the concentration of the gas exhausted from the gas outlet (solid-gas separation device 52) of the reaction device 50. The amount of calcium oxide conveyed to the calcium oxide inlet of the reaction device 50 may be adjusted based on one or both of the CO ₂ concentrations. Alternatively, the amount of calcium oxide to be transported to the calcium oxide inlet of the reaction device 50 is based on one or both of the temperature of the gas exhausted from the gas outlet of the reaction device 50 and the temperature of calcium carbonate taken out from the calcium carbonate outlet. It may also be configured to adjust. Further, based on one or both of the temperature of the gas introduced from the exhaust gas introduction port of the reaction device 50 and the temperature of the calcium oxide introduced into the calcium oxide introduction port of the reaction device 50, A configuration may be adopted in which the amount of calcium oxide to be transported is adjusted.

A cooler 56 for cooling the calcined cement raw material is arranged in the second conveyance path A2. Cooler 56 may be a heat exchanger.

The combustion gas pipe 23 heats the inside of the indirect heating type calciner 20 by generating combustion gas by combustion of a gas mixture containing fuel gas and combustion air supplied from the outside. In this embodiment, natural gas is used as the fuel gas, and high temperature air CG taken out from the clinker cooler 13 is used as the combustion air. As the combustion gas, high-temperature combustion gas produced by burning fuel such as natural gas, oil, or coal in a separate combustion furnace can be used.

The combustion exhaust gas pipe 30 supplies the exhaust gas (combustion exhaust gas) sent from the combustion gas pipe 23 to the solid-gas separator 31 .

The solid-gas separator 31 has a combustion exhaust gas inlet connected to the combustion exhaust gas pipe 30, a calcium carbonate outlet, a solid matter outlet, and a gas outlet. Further, the reaction device 50 has a kiln exhaust gas inlet connected to the kiln exhaust gas pipe 14. The solid-gas separator 31 mixes combustion exhaust gas and kiln exhaust gas to generate mixed exhaust gas. The solid-gas separator 31 mixes combustion exhaust gas and kiln exhaust gas to generate mixed exhaust gas, and separates the mixed exhaust gas from the solid content in the mixed exhaust gas. A gas outlet of the solid-gas separator 31 is connected to an intake port (piping 42a) of the exhaust gas heat exchanger 40. The solid matter outlet of the solid-gas separator 31 is connected to the conveyance path B. The conveyance path B is connected to a raw material inlet of the indirect heating type calcining furnace 20.

The exhaust gas heat exchanger 40 includes three solid-gas separators 41a, 41b, and 41c arranged in series in the vertical direction, and pipes 42a, 42b, and 42c that connect the solid-gas separators 41a, 41b, and 41c. . The uppermost solid-gas separator 41c is connected to the reactor 50. A cement raw material inlet is provided in the pipe 42c between the uppermost solid-gas separator 41c and the middle solid-gas separator 41b. The amount of cement raw material input is controlled by a cement raw material amount control device. The cement raw material taken out from the solid matter outlet of the solid-gas separator 41a at the lowest stage is conveyed to the kiln exhaust gas pipe 14. For example, cyclones can be used as the solid-gas separators 41a, 41b, and 41c. The exhaust gas heat exchanger 40 acts as a preheater that preheats the cement raw material by bringing the mixed exhaust gas into contact with the cement raw material introduced from the cement raw material input port. The exhaust port of the exhaust gas heat exchanger 40 is connected to the gas inlet (reaction tube 51) of the reaction device 50.

The reaction apparatus 50 includes a reaction tube 51 having an exhaust gas inlet, and a solid-gas separator 52 connected to the reaction tube 51 .
A blower 53 is disposed in the reaction tube 51. The reaction tube 51 has an inlet for introducing the calcined cement raw material, which is connected to the second transport path A2. In the reaction tube 51, the mixed exhaust gas sent by the blower 53 is brought into contact with the calcined cement raw material sent from the second transport path A2. As a result, _CO2 in the mixed exhaust gas reacts with calcium oxide in the calcined cement raw material to generate a reaction product gas from which calcium carbonate and _CO2 have been removed.

The solid-gas separator 52 separates the calcium carbonate produced in the reaction tube 51 and the reaction product gas into solid-gas. As the solid-gas separator 52, for example, a cyclone can be used. The solid-gas separator 52 has a reaction product gas outlet and a calcium carbonate outlet. The outlet for the reaction product gas is connected to the mixed exhaust gas inlet (piping 62a) of the reaction product gas heat exchanger 60. The calcium carbonate outlet is connected to the conveyance path C. The conveyance path C is connected to a raw material inlet of the indirect heating type calcining furnace 20.

The reaction product gas heat exchanger 60 includes three solid-gas separators 61a, 61b, and 61c arranged in series in the vertical direction, and pipes 62a, 62b, and 62c that connect the solid-gas separators 61a, 61b, and 61c. has. The uppermost solid-gas separator 61c is connected to an exhaust gas pipe 62d. A blower 63 is arranged in the exhaust gas pipe 62d. A pipe 62c between the uppermost solid-gas separator 61c and the middle solid-gas separator 61b includes a cement raw material input port. The amount of cement raw material input is controlled by a cement raw material amount control device. The solid matter outlet of the solid-gas separator 61a at the lowest stage is connected to the conveyance path D. The conveyance path D is connected to the conveyance path C. For example, cyclones can be used as the solid-gas separators 61a, 61b, and 61c. The reaction product gas heat exchanger 60 acts as a preheater that preheats the cement raw material by bringing the reaction product gas into contact with the cement raw material introduced from the cement raw material input port.

Next, a CO ₂ recovery method and a cement manufacturing method using the CO ₂ recovery system 101 of the cement manufacturing equipment of the first embodiment will be described.
The CO ₂ recovery method includes a CO ₂ recovery process, a cooling process, a calcium carbonate generation process, and a calcium carbonate supply process.

In the CO ₂ recovery step, the cement raw material introduced from the raw material inlet of the indirect heating type calciner 20 is indirectly heated and calcined using combustion gas to generate a cement raw material calcined product and CO ₂ . The cement raw materials include preheated cement raw materials conveyed by conveyance paths B, D, and E to the raw material inlet, and calcium carbonate conveyed by conveyance path C. The CO ₂ recovery process is performed in an indirect heating type calcining furnace 20. In this embodiment, combustion gas is generated in the combustion gas pipe 23 of the indirect heating type calcination furnace 20 by combustion of a gas mixture containing fuel gas and combustion air, and the temperature inside the indirect heating type calcination furnace 20 is controlled. By raising the temperature, the cement raw material is heated and calcined to generate a cement raw material calcined product and _CO2 . By using the indirect heating type calcining furnace 20, the cement raw material can be calcined without bringing the cement raw material into contact with combustion gas. Therefore, the only gas generated in the indirect heating type calcining furnace 20 is CO ₂ , and the CO ₂ concentration in the indirect heating type calcining furnace 20 is 100% or a value close to it.

The temperature in the indirect heating type calcining furnace 20 is a temperature at which calcium carbonate contained in the cement raw material is thermally decomposed to produce calcium oxide. The thermal decomposition temperature of calcium carbonate varies depending on the pressure inside the indirectly heated calciner 20. The thermal decomposition temperature of calcium carbonate decreases as the pressure within the indirectly heated calciner 20 decreases. As a method of lowering the pressure inside the indirect heating type calcining furnace 20, for example, a pressure reducing type blower is used as the blower 73. The temperature in the indirect heating type calcining furnace 20 is, for example, 700° C. or more and 1000° C. or less.

The CO ₂ generated in the indirect heating type calcining furnace 20 is sent to the CO ₂ heat exchanger 70 through the calcined material take-out pipe 21 and the solid-gas separator 22 . When the CO ₂ and the cement raw material come into contact with each other in the CO ₂ heat exchanger 70, the heat of the CO ₂ is transferred to the cement raw material, the cement raw material is preheated, and the temperature of the CO ₂ is lowered. The heat-exchanged CO ₂ can be taken out from the exhaust CO ₂ pipe 72d of the CO ₂ heat exchanger 70. The CO ₂ taken out to the outside is fixed, for example, by storing it underground or under the seabed. The preheated cement raw material is separated by the solid-gas separator 71a, and conveyed to the raw material inlet of the indirect heating type calciner 20 via the conveyance path E.

In the cooling process, the combustion exhaust gas discharged from the indirect heating type calciner 20 is cooled to 450° C. or lower. The high-temperature mixed gas containing the combustion exhaust gas discharged from the indirect heating type calciner 20 is sent to the solid-gas separator 31 via the combustion exhaust gas pipe 30, and is mixed with the kiln exhaust gas in the solid-gas separator 31. to generate mixed exhaust gas. The temperature of the mixed exhaust gas in the solid-gas separator 31 is, for example, 750° C. or higher and 850° C. or lower. The reaction between calcium oxide and _CO2 to produce calcium carbonate is an exothermic reaction. Therefore, when the mixed exhaust gas and the calcined cement raw material sent from the second conveyance path A2 are brought into contact at the above temperature and the mixed exhaust gas and the calcium oxide in the calcined cement raw material are reacted, the high-temperature mixed gas There is a possibility that the temperature will further rise, and the reaction between calcium oxide and CO ₂ will be suppressed, making it difficult to produce calcium carbonate. Therefore, in this embodiment, the temperature of the mixed exhaust gas is set to 450°C or lower, preferably 300°C or lower in the cooling process.

The cooling process is performed in the exhaust gas heat exchanger 40. In this embodiment, the cooling process is performed as follows. The mixed exhaust gas introduced into the pipe 42a of the exhaust gas heat exchanger 40 flows upward. Cement raw material is supplied to the pipe 42c with respect to this mixed exhaust gas. The cement raw material supplied to the pipe 42c flows into the solid-gas separator 41c together with the mixed exhaust gas flowing through the pipe 42c. The cement raw material and the mixed exhaust gas are separated in the solid-gas separator 41c, and the separated cement raw material is sent to the pipe 42b. The cement raw material sent to the pipe 42b flows into the solid-gas separator 41b together with the mixed exhaust gas flowing through the pipe 42b. The cement raw material and the mixed exhaust gas are separated in the solid-gas separator 41b, and the separated cement raw material is sent to the pipe 42a. The cement raw material sent to the pipe 42a flows into the solid-gas separator 41a together with the mixed exhaust gas flowing through the pipe 42a. The cement raw material and the mixed exhaust gas are separated in the solid-gas separator 41a, and the separated cement raw material is sent to the kiln exhaust gas pipe 14. The cement raw material sent to the kiln exhaust gas pipe 14 flows into the solid-gas separator 31 along with the kiln exhaust gas flowing through the kiln exhaust gas pipe 14 . The cement raw material and the mixed exhaust gas are separated in the solid-gas separator 31, and the separated cement raw material is sent to the raw material inlet of the indirect heating type calciner 20 via a conveyance path B. When the cement raw material and the mixed exhaust gas come into contact, the heat of the mixed exhaust gas is transferred to the cement raw material, the cement raw material is preheated, and the temperature of the mixed exhaust gas is lowered.

In the calcium carbonate generation step, the combustion exhaust gas (mixed exhaust gas) cooled to 450° C. or lower is brought into contact with calcium oxide, thereby causing the CO ₂ in the combustion exhaust gas to react with the calcium oxide to generate calcium carbonate. The calcium carbonate production process is performed in the reaction tube 51 of the reaction device 50. In this embodiment, the calcium carbonate generation step is performed as follows. The mixed exhaust gas introduced into the reaction tube 51 of the reaction device 50 is brought into contact with the cement raw material calcined material introduced into the reaction tube 51, and the CO ₂ in the mixed exhaust gas and the calcium oxide in the cement raw material calcined material are reacted. The temperature of the reaction products (calcium carbonate and reaction product gas) produced by the reaction of calcium oxide and CO ₂ is preferably 750° C. or lower. When the temperature of the reaction product is within this range, the reaction between calcium oxide and CO ₂ is likely to occur, and calcium carbonate is likely to be produced. In order to lower the temperature of the reaction product, the calcined cement raw material introduced into the reaction tube 51 is preferably cooled to 300° C. or lower in the cooler 56. Alternatively, a cooling section may be provided in one or both of the reaction tube 51 and the solid-gas separator 52 to cool the interior of one or both of the reaction tube 51 and the solid-gas separator 52 to 750° C. or lower. As the cooling section, a boiler that generates water vapor by absorbing heat from water can be used.

In the calcium carbonate supply step, the calcium carbonate produced in the calcium carbonate production step is supplied to the raw material inlet of the indirect heating type calciner 20. The calcium carbonate supply step is performed in the solid-gas separator 52 and the conveyance path C of the reaction device 50. In this embodiment, the calcium carbonate supply step is performed as follows. The reaction products (calcium carbonate and reaction product gas) produced in the reaction tube 51 of the reactor 50 are sent to the solid-gas separator 52. In the solid-gas separator 52, the reaction product is separated into calcium carbonate and reaction product gas. Calcium carbonate is taken out from the calcium carbonate outlet of the solid-gas separator 52 and sent to the raw material inlet of the indirect heating type calciner 20 via the conveyance path C. In the indirect heating type calcining furnace 20, calcium carbonate is heated and calcined to generate a calcined cement raw material and _CO2 . CO ₂ generated from calcium carbonate contains a large amount of fuel-derived CO ₂ . Therefore, CO ₂ derived from fuel can be efficiently recovered.

The reaction product gas taken out from the reaction product gas outlet of the solid-gas separator 52 is sent to the reaction product gas heat exchanger 60. In the reaction product gas heat exchanger 60, the reaction product gas comes into contact with the cement raw material, so that the heat of the reaction product gas is transferred to the cement raw material, preheating the cement raw material, and increasing the temperature of the reaction product gas. descend. Since the heat-exchanged reaction product gas does not contain much CO ₂ , it can be discharged to the outside from the exhaust gas pipe 62 d of the reaction product gas heat exchanger 60 . Further, the heat of the heat-exchanged reaction product gas may be recovered by a waste heat boiler or used for drying cement raw materials.

Cement production is performed in a cement production kiln 10.
In this embodiment, the cement raw material calcined product separated in the solid-gas separator 22 is conveyed to the cement manufacturing kiln 10 by the first conveyance path A1 after passing through the calcium oxide amount control device 55. The cement raw material calcined material transported from the first transport path A1 is fired by the main burner 12 in the furnace body 11 of the cement manufacturing kiln 10, thereby producing cement clinker.
The generated cement clinker is sent to a clinker cooler 13. The cement clinker is cooled in the clinker cooler 13. The cooled cement clinker is crushed and classified and used as cement.

According to the CO ₂ recovery system 101 for cement manufacturing equipment of this embodiment configured as described above, the cement raw material is indirectly calcined using combustion gas in the indirect heating type calcining furnace 20. Since the cement raw material calcined product and CO ₂ are generated in this way, a high concentration of CO ₂ can be generated in the indirect heating type calcining furnace 20 . In addition, in the reaction device 50, CO ₂ in the combustion exhaust gas and calcium oxide are reacted to generate calcium carbonate, and the generated calcium carbonate is supplied to the indirect heating type calciner 20 through the conveyance path C, so that combustion is possible. _CO2 in exhaust gas can be recovered. Furthermore, after reducing the temperature of the combustion exhaust gas using an exhaust gas heat exchanger, calcium oxide and CO ₂ are reacted in the reaction device, so that the reaction between CO ₂ and calcium oxide in the reaction device 50 is prevented. promoted. Therefore, the efficiency of collecting CO ₂ in the combustion exhaust gas is improved. Therefore, according to the CO ₂ recovery system 101 for cement manufacturing equipment, CO ₂ originating from raw materials and CO ₂ originating from fuel can be efficiently recovered. Furthermore, by using the heat generated by the reaction between calcium oxide and _CO2 in combustion exhaust gas to preheat cement raw materials, the amount of heat (amount of combustion gas used) when indirectly heating cement raw materials can be reduced. be able to. Therefore, the amount of CO ₂ generated from fuel can be reduced.

Further, in the case where the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment includes the kiln exhaust gas pipe 14 that conveys the exhaust gas of the cement manufacturing kiln 10 to the intake port (piping 42a) of the exhaust gas heat exchanger 40, CO ₂ in the exhaust gas of the cement manufacturing kiln 10 can be recovered together with the CO ₂ in the combustion exhaust gas. In addition, the amount of combustion gas used in the cement manufacturing kiln 10 can be reduced by using the reaction heat generated by reacting CO ₂ and calcium oxide in the exhaust gas of the cement manufacturing kiln 10 for preheating cement raw materials. can be made smaller. Therefore, the amount of CO ₂ generated from fuel can be reduced.

In addition, in the CO ₂ recovery system 101 of the cement manufacturing equipment of the present embodiment, the cement raw material calcined material contains calcium oxide, and the cement raw material calcined material taken out from the calcined material outlet of the indirect heating type calcining furnace 20 is used for cement production. In the case of having a first conveyance path A1 for conveying to the production kiln and a second conveyance path A2 for conveying to the calcium oxide inlet of the reaction device, CO ₂ in the combustion exhaust gas is recovered using the calcined cement raw material. can do. Moreover, it becomes easy to adjust the amount of calcium oxide brought into contact with CO ₂ in the combustion exhaust gas.

Moreover, in the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment, when the cooler 56 is arranged in the second conveyance path A2, the temperature of the calcium oxide brought into contact with the combustion exhaust gas can be lowered. Even if reaction heat is generated by reacting CO ₂ in the combustion exhaust gas with calcium oxide, the temperature of the produced calcium carbonate can be maintained at a predetermined temperature. Therefore, the temperature of the combustion exhaust gas becomes difficult to rise, and CO ₂ in the combustion exhaust gas can be recovered with higher efficiency.

In addition, in the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment, the amount of cement raw material calcined material to be transported to the cement manufacturing kiln 10 and the amount of cement raw material calcined material to be transported to the calcium oxide inlet of the reaction device 50. In the case of having a calcium oxide amount control device 55 that controls _the The required amount of calcium oxide can be delivered to the reactor 50, which allows fuel-originated CO ₂ to be recovered with higher efficiency.

In addition, in the CO ₂ recovery system 101 of the cement manufacturing equipment of the present embodiment, the calcium oxide amount control device 55 controls the CO ₂ concentration of the gas introduced from the gas inlet (reaction tube 51 ) of the reaction device 50 . When adjusting the amount of calcium oxide to be transported to the calcium oxide inlet of the reaction device 50 based on one or both of the CO ₂ concentrations of the gas exhausted from the gas outlet (solid-gas separator 52), the combustion exhaust gas It is possible to reliably supply the reactor 50 with the necessary amount of calcium oxide to recover the CO ₂ therein. Therefore, CO ₂ in the combustion gas can be recovered with even higher efficiency.

In the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment, the calcium oxide amount control device 55 controls the temperature of the gas exhausted from the gas outlet of the reaction device 50, and the amount of calcium carbonate taken out from the calcium carbonate outlet. When adjusting the amount of calcium oxide to be conveyed to the calcium oxide inlet of the reaction device 50 based on one or both of the temperatures, the amount of calcium oxide required to recover CO ₂ in the combustion exhaust gas can be adjusted to the reaction device 50 based on one or both of the temperatures. can be reliably supplied. Therefore, CO ₂ in the combustion gas can be recovered with even higher efficiency.

Further, in the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment, the calcium oxide amount control device 55 controls the temperature of the gas introduced from the exhaust gas inlet of the reaction device 50 and the temperature of the gas introduced into the calcium oxide inlet of the reaction device 50. When adjusting the amount of calcium oxide to be transported to the calcium oxide inlet of the reaction device 50 based on the temperature of the calcium oxide and/or both, it is necessary to adjust the amount of oxidation necessary to recover CO ₂ in the combustion exhaust gas. Calcium can be supplied to the reaction device 50 more reliably. Therefore, CO ₂ in the combustion gas can be recovered with even higher efficiency.

In addition, in the CO ₂ recovery system 101 of the cement manufacturing equipment of the present embodiment, the calcium oxide amount control device 55 controls the CO ₂ concentration of the gas introduced from the gas inlet (reaction tube 51 ) of the reaction device 50 . When adjusting the amount of calcium oxide to be transported to the calcium oxide inlet of the reaction device 50 based on one or both of the CO ₂ concentrations of the gas exhausted from the gas outlet (solid-gas separator 52), the combustion exhaust gas It is possible to reliably supply the reactor 50 with the necessary amount of calcium oxide to recover the CO ₂ therein. Therefore, CO ₂ in the combustion gas can be recovered with even higher efficiency.

In addition, in the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment, the exhaust gas heat exchanger 40 has a cement raw material input port, and a solid gas separation unit that separates the cement raw material supplied from the cement raw material input port from the combustion exhaust gas. If the preheater includes devices 41a, 41b, and 41c and is configured with a cement raw material amount control device that controls the amount of cement raw material supplied from the cement raw material input port of the preheater, the heat of the combustion exhaust gas Since the cement raw material is preheated, the amount of heat when indirectly heating the cement raw material, that is, the amount of combustion gas used can be reduced. Therefore, the amount of CO ₂ generated from fuel can be reduced.

In addition, in the case where the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment has a cooling section in the reaction device 50, the temperature inside the reaction device 50 is lowered using the cooling section. The reaction between CO ₂ and calcium oxide is promoted. Therefore, the recovery efficiency of CO ₂ in the combustion exhaust gas is improved.

Further, in the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment, when the cooling unit is a boiler that generates water vapor by absorbing heat from water, the temperature inside the reaction device 50 can be efficiently lowered.

In addition, in the case where the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment includes a pressure reducing device that reduces the internal pressure of the indirectly heated calcining furnace 20, by reducing the internal pressure of the indirectly heated calcining furnace 20, , the thermal decomposition temperature of calcium carbonate in the indirect heating type calcining furnace 20 can be lowered. Thereby, the amount of heat when indirectly heating the cement raw material, that is, the amount of combustion gas used can be reduced. Therefore, the amount of CO ₂ generated from fuel can be reduced.

In addition, in the case where the CO ₂ recovery system 101 of the cement manufacturing equipment of this embodiment includes a pressurizing device that pressurizes the internal pressure of the reaction device 50, by pressurizing the internal pressure of the reaction device 50, the thermal decomposition temperature of calcium carbonate is increased. can be made higher. Thereby, the reaction between CO ₂ in the combustion exhaust gas and calcium oxide is promoted, and the CO ₂ in the combustion exhaust gas can be recovered with even higher efficiency.

Further, according to the CO ₂ recovery method of the cement manufacturing equipment of this embodiment configured as described above, in the CO ₂ recovery process, cement raw materials are indirectly calcined using combustion gas to produce cement. Since the raw material calcined product and CO ₂ are generated, a high concentration of CO ₂ can be generated in the indirect heating type calciner 20. In addition, in the calcium carbonate generation process, CO ₂ in the combustion exhaust gas and calcium oxide are reacted to generate calcium carbonate, and in the calcium carbonate supply process, the generated calcium carbonate is indirectly heated calcined in the conveyance path C. Since it is supplied to the furnace, CO ₂ in the combustion exhaust gas can be recovered. Furthermore, in the cooling process, the temperature of the combustion exhaust gas is reduced to 450°C or less using an exhaust gas heat exchanger, and then in the calcium carbonate generation process, CO ₂ in the combustion exhaust gas and calcium oxide are reacted. , the reaction between CO ₂ and calcium oxide is promoted. Therefore, the efficiency of collecting CO ₂ in the combustion exhaust gas is improved. Therefore, according to the CO ₂ recovery method for cement manufacturing equipment of the present embodiment, CO ₂ originating from raw materials and CO ₂ originating from fuel can be efficiently recovered. Furthermore, the amount of combustion gas used can be reduced by using the heat generated by the reaction between calcium oxide and CO ₂ in the combustion exhaust gas to preheat cement raw materials.

In the CO ₂ recovery method for cement manufacturing equipment of the present embodiment, before introducing the combustion gas into the exhaust gas heat exchanger 40, the combustion exhaust gas and the exhaust gas generated in the cement manufacturing kiln 10 are mixed to produce a mixed exhaust gas. When the mixed exhaust gas is cooled to 450° C. or lower in the cooling step, CO ₂ in the exhaust gas of the cement production kiln can be recovered together with the CO ₂ in the combustion exhaust gas. In addition, by using the reaction heat generated by reacting CO ₂ and calcium oxide in the exhaust gas of the cement production kiln 10 for preheating the cement raw materials, the combustion gas when indirectly heating the cement raw materials can be used. The amount of combustion gas used and the amount of combustion gas used in the cement manufacturing kiln 10 can be further reduced. Therefore, the amount of CO ₂ generated from fuel can be reduced.

(Second embodiment)
FIG. 1 is a schematic configuration diagram showing a CO ₂ recovery system for cement manufacturing equipment according to a second embodiment of the present invention. In addition, in FIG. 2, the same components as those of the CO ₂ recovery system 101 of the cement manufacturing equipment according to the first embodiment shown in FIG. 1 are given the same reference numerals, and the explanation thereof will be simplified.

As shown in FIG. 2, in the CO ₂ recovery system 102 for cement manufacturing equipment according to the second embodiment, a gas conveying pipe 80 containing CO ₂ from a different source is connected to the reaction tube 51 of the reaction device 50. The different emission source CO ₂ -containing gas is a CO ₂ -containing gas generated in a device other than the cement manufacturing kiln 10 and the indirectly heated calciner 20 . The temperature of the gas containing CO ₂ from different sources is below 450°C, preferably below 300°C.

In the CO ₂ recovery system 102 of the cement manufacturing equipment of this embodiment, there is a CO _{2 -containing gas containing the mixed exhaust gas sent from the exhaust gas heat exchanger 40 and a different emission source CO 2 -containing} gas in the reaction tube 51 . . Then, by bringing the generated CO ₂ -containing gas into contact with the calcined cement raw material, a reaction product gas from which calcium carbonate and CO ₂ have been removed is generated.

The CO ₂ recovery system 102 of the cement manufacturing equipment _of this embodiment is the same as the CO ₂ recovery system 102 of the cement manufacturing equipment of FIG. Therefore, it has the same effect as the CO ₂ recovery system 101 of cement manufacturing equipment. Furthermore, since the CO ₂ recovery system 102 of the cement manufacturing equipment of this embodiment reacts CO 2 in the gas containing CO ₂ from different emission sources with calcium oxide, CO ₂ in the gas containing _{CO 2 from} different emission sources can be easily recovered. Moreover, it can be efficiently recovered and CO ₂ released into the atmosphere can be reduced.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto and can be modified as appropriate without departing from the technical idea of the invention.
For example, in the present embodiment, the indirect heating type calcination furnace 20 is configured to include a combustion gas pipe 23 through which combustion gas flows; There is no particular restriction on the configuration of the calcining furnace as long as it is configured so that the temperature inside the furnace can be adjusted without direct contact with the calciner. The indirect heating type calcining furnace 20 may use a solid heat medium to adjust the temperature inside the furnace. The indirect heating type calcination furnace 20 has, for example, a heat medium heating section and a cement raw material calcination section, and the heat medium heated using combustion gas in the heat medium heating section is supplied to the cement raw material calcination section. It is possible to use a device that adjusts the temperature inside the furnace. In this indirect heating type calciner, the combustion gas discharged from the heat medium heating section becomes combustion exhaust gas. In addition, a part of the calcined cement raw material separated in the solid-gas separator 22 connected to the indirect heating type calcination furnace 20 is returned to the indirect heating type calcination furnace 20 via the heat medium heating section as a heat medium. You can. Furthermore, a part of the clinker obtained in the cement production kiln 10 may be supplied to the indirect heating type calcining furnace 20 as a heat medium.

10 Cement production kiln 11 Furnace body 12 Main burner 13 Clinker cooler 14 Kiln exhaust gas pipe 20 Indirect heating type calciner 21 Calcined product take-out pipe 22 Solid gas separation device 23 Combustion gas pipe 30 Combustion exhaust gas pipe 31 Solid gas separation device 40 Exhaust gas Heat exchanger 41a, 41b, 41c Solid-gas separator 42a, 42b, 42c Piping 50 Reactor 51 Reaction tube 52 Solid-gas separator 53 Air blower 55 Calcium oxide amount control device 56 Cooler 60 Reaction product gas heat exchanger 61a, 61b , 61c Solid gas separation device 62a, 62b, 62c Piping 62d Exhaust gas pipe 63 Blower 70 CO ₂ heat exchanger 71a, 71b, 71c Solid gas separation device 72a, 72b, 72c Piping 72d Exhaust CO ₂ pipe 72d
73 Air blower 80 Different emission source CO ₂ containing gas conveyance piping 101, 102 CO ₂ recovery system for cement manufacturing equipment

Claims (16)

A cement production kiln, comprising a raw material inlet, a calcined product outlet, and a _CO2 outlet, and indirectly calcinates the cement raw material introduced from the raw material inlet using combustion gas. A CO ₂ recovery system for a cement manufacturing facility having an indirect heating type calcining furnace that generates a cement raw material calcined product and CO ₂ ,
a combustion exhaust gas pipe through which exhaust gas including combustion exhaust gas discharged from the indirect heating calciner flows;
an exhaust gas heat exchanger having an intake port connected to the combustion exhaust gas pipe and an exhaust port;
It has an exhaust gas inlet connected to the exhaust port of the exhaust gas heat exchanger, a calcium oxide inlet, a calcium carbonate outlet, and a gas outlet, and the exhaust gas introduced from the exhaust gas inlet and the calcium oxide A reaction device that causes CO ₂ in the exhaust gas to react with the calcium oxide to produce calcium carbonate by bringing the calcium oxide into contact with the calcium oxide introduced from the inlet;
A CO ₂ recovery system for cement manufacturing equipment, comprising: a conveying device that conveys the calcium carbonate taken out from the calcium carbonate outlet of the reaction device to the raw material inlet of the indirect heating calciner. The CO ₂ recovery system for cement manufacturing equipment according to claim 1, further comprising piping that conveys exhaust gas generated in the cement manufacturing kiln to the intake port of the exhaust gas heat exchanger. a first conveyance path for transporting the calcined cement raw material containing calcium oxide and the calcined cement raw material taken out from the calcined material outlet of the indirect heating type calcining furnace to the cement manufacturing kiln; The CO ₂ recovery system for cement production equipment according to claim 1 or 2, further comprising a second conveyance path for conveying the calcium oxide to the calcium oxide inlet of the reaction device. The CO ₂ recovery system for cement manufacturing equipment according to claim 3, wherein a cooler is disposed in the second conveyance path. Claim 3, further comprising a calcium oxide amount control device for controlling the amount of the calcined cement raw material to be transported to the cement manufacturing kiln and the amount of the calcined cement raw material to be transported to the calcium oxide inlet of the reaction device. A CO ₂ recovery system for cement manufacturing equipment as described in . The CO2 recovery system for a cement manufacturing facility according to claim 5, wherein the calcium oxide amount control device adjusts the amount of calcium _oxide to be transported to the calcium oxide inlet of the reaction device based on one or both of the CO2 concentration of the gas introduced from the exhaust gas inlet of the reaction device and the _CO2 concentration of the gas exhausted from the gas _exhaust outlet of the reaction device. The calcium oxide amount control device controls the amount of calcium oxide in the reaction device based on one or both of the temperature of the gas exhausted from the gas extraction outlet of the reaction device and the temperature of calcium carbonate taken out from the calcium carbonate extraction port. The CO ₂ recovery system for cement manufacturing equipment according to claim 5, wherein the amount of calcium oxide conveyed to the calcium oxide inlet is adjusted. The calcium oxide amount control device further controls the amount of calcium oxide based on one or both of the temperature of the gas introduced from the exhaust gas introduction port of the reaction device and the temperature of calcium oxide introduced into the calcium oxide introduction port of the reaction device. 8. The CO ₂ recovery system for cement manufacturing equipment according to claim 7, wherein the amount of calcium oxide conveyed to the calcium oxide inlet of the reaction device is adjusted. The exhaust gas heat exchanger is a preheater including a cement raw material input port and a solid-gas separator that separates the cement raw material supplied from the cement raw material input port from the combustion exhaust gas, The CO ₂ recovery system for cement manufacturing equipment according to claim 1 or 2, further comprising a cement raw material amount control device that controls the amount of cement raw material supplied from the input port. The CO ₂ recovery system for cement manufacturing equipment according to claim 1 or 2, further comprising a cooling section in the reaction device. The CO ₂ recovery system for cement manufacturing equipment according to claim 10, wherein the cooling unit is a boiler that generates water vapor by absorbing heat from water. The CO ₂ recovery system for cement manufacturing equipment according to claim 1 or 2, further comprising a pressure reducing device that reduces the internal pressure of the indirectly heated calciner. The CO ₂ recovery system for cement manufacturing equipment according to claim 1 or 2, further comprising a pressurizing device that pressurizes the internal pressure of the reaction device. Piping for conveying CO2 _- containing gas generated in other equipment other than the cement manufacturing kiln and the indirectly heated calciner to the inlet of the exhaust gas heat exchanger or the exhaust gas inlet of the reaction device. A CO ₂ recovery system for cement manufacturing equipment according to claim 1 or 2, comprising: A method for recovering CO ₂ in a cement manufacturing facility having a cement manufacturing kiln, and an indirect heating type calcining furnace comprising a raw material inlet, a calcined product outlet, and a CO ₂ outlet, the method comprising:
The cement raw material introduced from the raw material inlet of the indirect heating type calcining furnace is indirectly heated and calcined using combustion gas to generate a cement raw material calcined product and _CO2 , and the _CO2 is A CO ₂ recovery process to recover;
A cooling step of introducing the combustion exhaust gas discharged from the indirect heating type calciner into an exhaust gas heat exchanger and cooling it to 450 ° C. or less,
A calcium carbonate generation step of causing the CO ₂ in the combustion exhaust gas to react with the calcium oxide to generate calcium carbonate by bringing the combustion exhaust gas cooled to 450° C. or lower into contact with calcium oxide;
A CO ₂ recovery method for cement manufacturing equipment, comprising: a calcium carbonate supplying step of supplying the calcium carbonate to the raw material inlet of the indirect heating type calcining furnace. before introducing the combustion gas into the exhaust gas heat exchanger, a mixing step of mixing the combustion exhaust gas and the exhaust gas generated in the cement manufacturing kiln to generate a mixed exhaust gas; The CO ₂ recovery method for cement manufacturing equipment according to claim 15, wherein the exhaust gas is cooled to 450°C or less.

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