Combustion device system and ship

Abstract

This combustion device system comprises: a combustion device that burns a fuel; an exhaust gas line through which an exhaust gas from the combustion device flows; a discharge line that is connected to the exhaust gas line and discharges the exhaust gas from the exhaust gas line to the atmosphere; a recovery line that is branched and connected to the exhaust gas line; a carbon dioxide recovery device that is connected to the recovery line and recovers carbon dioxide contained in the exhaust gas from the exhaust gas line; and a denitration device that is provided on the upstream side of the carbon dioxide recovery device in the recovery line and treats nitrogen oxides contained in the exhaust gas.

Description

Combustion device system, ship

[0001] This disclosure relates to a combustion device system and a ship. This application claims priority to Japanese Patent Application No. 2024-210914 filed in Japan on December 4, 2024, the content of which is incorporated herein by reference.

[0002] Patent Document 1 discloses a carbon dioxide recovery device that recovers carbon dioxide from exhaust gas generated by burning natural gas.

[0003] Japanese Patent Application Laid-Open No. 2017-176954

[0004] By the way, the exhaust gas generated by burning fuels such as natural gas as in Patent Document 1 contains nitrogen oxides (NOx). Therefore, prior to releasing the exhaust gas into the atmosphere, it is necessary to perform a process of reducing the concentration of nitrogen oxides in the exhaust gas with a denitration device. However, depending on the performance of the denitration device, it may not be possible to remove the nitrogen oxides in the exhaust gas to the specified value. For this reason, depending on the performance of the denitration device employed, the exhaust gas containing nitrogen oxides may be introduced into the carbon dioxide recovery device. Then, nitrogen oxides will remain in the carbon dioxide recovered by the carbon dioxide recovery device. On the other hand, if an attempt is made to remove more nitrogen oxides, it will lead to an increase in the size of the denitration device.

[0005] Also, when both a denitration device and a carbon dioxide recovery device are provided, each of the denitration device and the carbon dioxide recovery device will be of a scale corresponding to the amount of exhaust gas to be treated. The scale of the denitration device and the carbon dioxide recovery device also affects the cost and the required installation space. Furthermore, the emission amounts of nitrogen oxides and carbon dioxide respectively need to be below the specified regulatory values. For this reason, there is a problem that it is difficult to balance the required performance of the denitration device and the carbon dioxide recovery device with the device scale.

[0006] This disclosure has been made to solve the above problems, and an object thereof is to provide a combustion device system and a ship that can achieve a good balance between the performance necessary for sufficiently treating nitrogen oxides and carbon dioxide and the device scale.

[0007] To solve the above problems, the combustion system and ship according to this disclosure comprises a combustion device, an exhaust gas line, a discharge line, a recovery line, a carbon dioxide recovery device, and a denitrification device. The combustion device burns fuel. The exhaust gas line through which exhaust gas from the combustion device flows. The discharge line is connected to the exhaust gas line and releases the exhaust gas from the exhaust gas line into the atmosphere. The recovery line is branched and connected to the exhaust gas line. The carbon dioxide recovery device is connected to the recovery line and recovers carbon dioxide contained in the exhaust gas from the exhaust gas line. The denitrification device is provided upstream of the carbon dioxide recovery device in the recovery line. The denitrification device processes nitrogen oxides contained in the exhaust gas.

[0008] The vessel relating to this disclosure comprises a hull and a combustion system as described above.

[0009] The combustion system and vessels of this disclosure provide a good balance between the performance necessary for adequately treating nitrogen oxides and carbon dioxide and the scale of the equipment.

[0010] This is a side view of a ship equipped with a combustion device system according to an embodiment of this disclosure. This is a diagram showing the configuration of a combustion device system according to the first embodiment of this disclosure. This is a diagram showing the configuration of a combustion device system according to a modified example of the first embodiment of this disclosure. This is a diagram showing the configuration of a combustion device system according to the second embodiment of this disclosure. This is a diagram showing the configuration of a combustion device system according to the third embodiment of this disclosure. This is a diagram showing the configuration of a combustion device system according to the fourth embodiment of this disclosure. This is a diagram showing the configuration of a combustion device system according to the fifth embodiment of this disclosure.

[0011] <First Embodiment> Hereinafter, the combustion device system and vessel according to the embodiment of this disclosure will be described with reference to Figures 1 to 7. (Overall Configuration of the Vessel) As shown in Figure 1, the vessel 1 of this embodiment comprises a hull 2 ​​and a combustion device system 20A. Note that the type of vessel 1 of this embodiment is not limited to a specific type of vessel. Examples of vessel types for the vessel 1 include liquefied gas carriers, ferries, RORO ships, car carriers, passenger ships, etc.

[0012] (Hull Structure) The hull 2 ​​has a pair of side panels 3A and 3B that form its outer shell, a bottom 4, and an upper deck 5. The side panels 3A and 3B each have a pair of side platings that form the left and right sides, respectively. The bottom 4 has bottom platings that connect these side panels 3A and 3B. The upper deck 5 is a full-length deck that is exposed to the outside, and a superstructure 6 containing living quarters is formed on this upper deck 5.

[0013] The combustion device 8 is a device that generates thermal energy by burning fuel and is installed inside the hull 2 ​​described above. Examples of combustion devices 8 include an internal combustion engine used as the main engine for propelling the ship 1, an internal combustion engine used in a power generation facility that supplies electricity to the ship, and a boiler that generates steam as a working fluid.

[0014] An engine casing 9 is provided on the upper deck 5. The engine casing 9 houses the discharge line 102, which will be described later, and other discharge lines 104.

[0015] (Configuration of the combustion device system) Figure 2 is a diagram showing the configuration of the combustion device system according to the first embodiment of the present disclosure. As shown in Figure 2, the combustion device system 20A comprises the combustion device 8, an exhaust gas line 101, a discharge line 102, a recovery line 103, a turbocharger 10, a treatment device 21A, a carbon dioxide recovery device 25, and a denitrification device 23.

[0016] The exhaust gas line 101 is connected to the exhaust port (not shown) of the combustion device 8. Exhaust gas from the combustion device 8 flows through this exhaust gas line 101.

[0017] The discharge line 102 is connected to the exhaust gas line 101. The discharge line 102 releases exhaust gas from the exhaust gas line 101 into the atmosphere. At least the downstream end of the discharge line 102 in the direction of exhaust gas flow is housed within the engine casing 9.

[0018] The recovery line 103 is branched and connected to the exhaust gas line 101. In this embodiment, the recovery line 103 branches off from the point where the exhaust gas line 101 and the discharge line 102 are connected.

[0019] The supercharger 10 utilizes the energy of the exhaust gas discharged from the combustion device 8 to pressurize and supply air to the combustion device 8. The supercharger 10 is, for example, a turbocharger. In this embodiment, the supercharger 10 is installed in the middle of the exhaust gas line 101.

[0020] The treatment device 21A is positioned upstream of the denitrification device 23 in the flow direction of exhaust gas from the combustion device 8. The treatment device 21A processes nitrogen oxides contained in the exhaust gas from the combustion device 8. In this embodiment, a selective catalytic reduction device (SCR) is used as the treatment device 21A. The denitrification mechanism in the SCR, which is the treatment device 21A, is the same as that of the denitrification device 23, which will be described later. Note that the treatment device 21A may use a different reducing agent than that used in the denitrification device 23.

[0021] In this embodiment, the treatment device 21A is provided in the exhaust gas line 101. The treatment device 21A may be directly connected to the exhaust port of the combustion device 8, but even in this case, the treatment device 21A can be said to be provided at the base end of the exhaust gas line 101 on the side closer to the combustion device 8.

[0022] In this embodiment, the treatment device 21A is positioned upstream of the turbocharger 10 in the direction of exhaust gas flow. When the combustion device 8 is a two-stroke engine, the exhaust gas temperature is lower compared to a four-stroke engine. In this case, by positioning the treatment device 21A upstream of the turbocharger 10 in the direction of exhaust gas flow, the exhaust gas can be supplied to the treatment device 21A while suppressing the drop in exhaust gas temperature, thereby enabling effective treatment of nitrogen oxides.

[0023] (Configuration of the carbon dioxide recovery device) The carbon dioxide recovery device 25 is connected to the recovery line 103. The carbon dioxide recovery device 25 is installed, for example, on the upper deck 5. The carbon dioxide recovery device 25 may also be housed inside the hull 2. Exhaust gas is fed into the carbon dioxide recovery device 25 from the exhaust gas line 101 through the recovery line 103. The carbon dioxide recovery device 25 recovers carbon dioxide contained in the exhaust gas fed into the recovery line 103.

[0024] One method for recovering carbon dioxide in the carbon dioxide recovery device 25 is a chemical absorption method in which carbon dioxide is absorbed by an absorbent liquid. MEA (monoethanolamine) can be used as an example of an absorbent liquid when carbon dioxide is absorbed by the chemical absorption method. The configuration of the carbon dioxide recovery device 25 is not limited in any way. The size of the carbon dioxide recovery device 25 is set according to the amount of exhaust gas sent from the exhaust gas line 101 through the recovery line 103.

[0025] After carbon dioxide has been absorbed into the absorbent liquid by the carbon dioxide recovery device 25, the exhaust gas is released into the atmosphere through another discharge line 104. Of the other discharge line 104, at least the downstream end in the direction of exhaust gas flow is housed, for example, within the engine casing 9. However, there are no limitations on the location of the downstream end of the discharge line 104.

[0026] (Configuration of the denitrification device) The denitrification device 23 is located upstream of the carbon dioxide recovery device 25 in the recovery line 103. The denitrification device 23 processes nitrogen oxides contained in the exhaust gas sent from the exhaust gas line 101 to the recovery line 103. In this embodiment, a selective catalytic reduction device (SCR) is used as the denitrification device 23. The denitrification device 23 uses urea as a reducing agent, for example. When urea is injected into high-temperature exhaust gas in the denitrification device 23, ammonia and carbon dioxide are produced by the reactions described in (1) and (2) below. CO(NH ２ ) ２ → NH ３ + HCNO...(1) HCNO+H ２ O → NH ３ + CO ２ ... (2) In the denitrification apparatus 23, nitrogen oxides (NOx) react with the generated ammonia and catalyst to produce nitrogen (N ２ ) and water (H ２O) is broken down into two parts. The size of the denitrification device 23 is set according to the amount of exhaust gas sent from the exhaust gas line 101 through the recovery line 103. In other words, the size of the denitrification device 23 depends on the carbon dioxide recovery capacity of the carbon dioxide recovery device 25.

[0027] (Operation of the Combustion System) In this combustion system 20A, exhaust gas from the combustion device 8 passes through the exhaust gas line 101 and is sent to the treatment device 21A. In the treatment device 21A, nitrogen oxides contained in the exhaust gas are treated. After passing through the treatment device 21A, the exhaust gas passes through the turbocharger 10 and is divided into a discharge line 102 and a recovery line 103. The exhaust gas that flows into the discharge line 102 is released directly into the atmosphere.

[0028] The exhaust gas that flows into the recovery line 103 is sent to the denitrification unit 23. In the denitrification unit 23, nitrogen oxides contained in the exhaust gas that has passed through the treatment device 21A are further processed. The exhaust gas that has passed through the denitrification unit 23 is sent to the carbon dioxide recovery unit 25. In the carbon dioxide recovery unit 25, carbon dioxide contained in the exhaust gas that has been sent in is recovered. In this embodiment, the carbon dioxide recovery unit 25 also recovers carbon dioxide generated from urea in the denitrification unit 23. The exhaust gas from which carbon dioxide has been recovered is released into the atmosphere through another discharge line 104.

[0029] (Effects) In the combustion device system 20A and ship 1 of the first embodiment described above, a denitrification device 23 is provided upstream of the carbon dioxide recovery device 25 in the recovery line 103 to which the carbon dioxide recovery device 25 is connected. The exhaust gas flowing into the recovery line 103 is treated for nitrogen oxides in the denitrification device 23 before being sent to the carbon dioxide recovery device 25. This suppresses the inclusion of nitrogen oxides in the carbon dioxide recovered by the carbon dioxide recovery device 25. It also suppresses the nitrogen oxides contained in the exhaust gas from which carbon dioxide has been recovered. Furthermore, the recovery line 103 is branched and connected to the exhaust gas line 101. For this reason, a portion of the exhaust gas from the combustion device 8 through the exhaust gas line 101 flows into the recovery line 103, is treated in the denitrification device 23 and the carbon dioxide recovery device 25, and the remainder of the exhaust gas is released into the atmosphere from the discharge line 102. Therefore, the denitrification unit 23 and the carbon dioxide recovery unit 25 do not need to process the entire amount of exhaust gas from the combustion unit 8, thus preventing the denitrification unit 23 and the carbon dioxide recovery unit 25 from becoming too large. Consequently, the scale of the denitrification unit 23 and the carbon dioxide recovery unit 25 can be adjusted to match the required performance, making it easier to balance the required performance of the denitrification unit 23 and the carbon dioxide recovery unit 25 with the size of the equipment. As a result, a good balance can be achieved between the performance necessary to adequately treat nitrogen oxides and carbon dioxide and the size of the equipment.

[0030] Furthermore, in the first embodiment described above, by providing the treatment device 21A upstream of the denitrification device 23 in the direction of exhaust gas flow, nitrogen oxides contained in the exhaust gas from the combustion device 8 can be treated by the treatment device 21A, and then further treated by the denitrification device 23 downstream. Therefore, the amount of nitrogen oxides contained in the exhaust gas sent to the carbon dioxide recovery device 25 can be reduced even further.

[0031] Furthermore, in the first embodiment described above, by providing the treatment device 21A in the exhaust gas line 101 into which the entire amount of exhaust gas from the combustion device 8 flows, nitrogen oxides contained in the entire amount of exhaust gas from the combustion device 8 can be treated by the treatment device 21A. Therefore, the amount of nitrogen oxides contained in the exhaust gas released into the atmosphere from the discharge line 102 can be reduced.

[0032] (Modification of the First Embodiment) Figure 3 is a diagram showing the configuration of a combustion device system according to a modification of the first embodiment of the present disclosure. As shown in Figure 3, the combustion device system 20A shown in the above embodiment may be provided with a control valve 50 for adjusting the amount of exhaust gas flowing into the recovery line 103. By adjusting the opening of the control valve 50, the amount of nitrogen oxides processed in the denitrification device 23 and the amount of carbon dioxide recovered in the carbon dioxide recovery device 25 can be adjusted. Therefore, for example, the processing amounts in the denitrification device 23 and the carbon dioxide recovery device 25 can be appropriately adjusted according to various regulations. As a result, the operating costs of the denitrification device 23 and the carbon dioxide recovery device 25 can be reduced.

[0033] <Second Embodiment> Next, a second embodiment of the combustion device system and vessel according to the present disclosure will be described. In the second embodiment described below, only the configuration of the combustion device system differs from that of the first embodiment, so the same reference numerals are used for the same parts as in the first embodiment, and redundant explanations will be omitted.

[0034] (Configuration of the Combustion System) Figure 4 is a diagram showing the configuration of the combustion system according to the second embodiment of the present disclosure. As shown in Figure 4, the combustion system 20B includes the combustion device 8, an exhaust gas line 101, a discharge line 102, a recovery line 103, a turbocharger 10, a processing device 21B, a carbon dioxide recovery device 25, and a denitrification device 23. The combustion system 20B in this embodiment differs from the combustion system 20A in the first embodiment in that it includes a processing device 21B instead of a processing device 21A.

[0035] The treatment device 21B processes nitrogen oxides contained in the exhaust gas from the combustion device 8. In this embodiment, an exhaust gas recirculation device (EGR) is used as the treatment device 21B. The EGR, which is the treatment device 21B, recirculates a portion of the exhaust gas flowing through the exhaust gas line 101 to the intake side of the combustion device 8 through the return line 105. One end of the return line 105 is connected to the treatment device 21B. The other end of the return line 105 may be connected to the intake side of the turbocharger 10 that pressurizes and supplies air to the combustion device 8, or it may be connected to the discharge side of the turbocharger 10. The combustion device 8 burns the exhaust gas recirculated through the return line 105 together with the air pressurized from the turbocharger 10, along with fuel, and processes the nitrogen oxides contained in the exhaust gas.

[0036] (Effects) In the combustion device system 20B and ship 1 of the second embodiment described above, a good balance can be achieved between the performance necessary to adequately treat nitrogen oxides and carbon dioxide and the scale of the device, similar to the first embodiment described above.

[0037] <Third Embodiment> Next, a third embodiment of the combustion device system and vessel according to the present disclosure will be described. In the third embodiment described below, only the configuration of the combustion device system differs from that of the first embodiment, so the same reference numerals are used for the same parts as in the first embodiment and redundant explanations are omitted.

[0038] (Configuration of the combustion device system) Figure 5 is a diagram showing the configuration of the combustion device system according to the third embodiment of the present disclosure. As shown in Figure 5, the combustion device system 20C comprises the combustion device 8, an exhaust gas line 101, a discharge line 102, a recovery line 103, a turbocharger 10, a processing device 21A, a carbon dioxide recovery device 25, and a denitrification device 23.

[0039] In this third embodiment, the supercharger 10 is provided in the discharge line 102.

[0040] In such a combustion device system 20C, the exhaust gas from the combustion device 8 passes through the exhaust gas line 101 and is sent into the processing device 21A. In the processing device 21A, the nitrogen oxides contained in the exhaust gas are processed. The exhaust gas that has passed through the processing device 21A is branched into a discharge line 102 and a recovery line 103. The exhaust gas flowing into the discharge line 102 is discharged directly into the atmosphere through the supercharger 10.

[0041] On the other hand, the exhaust gas flowing into the recovery line 103 is sent into the denitration device 23. In the denitration device 23, the nitrogen oxides contained in the exhaust gas that has passed through the processing device 21A are further processed. When the combustion device 8 is a two-stroke engine, the exhaust gas temperature is lower compared to a four-stroke engine. In this case, upstream of the supercharger 10, by sending the exhaust gas that remains at a high temperature without the supercharger 10 working into the recovery line 103, the nitrogen oxides can be efficiently processed in the denitration device 23. The exhaust gas that has passed through the denitration device 23 is sent into the carbon dioxide recovery device 25. In the carbon dioxide recovery device 25, the carbon dioxide contained in the sent exhaust gas is recovered. The exhaust gas from which carbon dioxide has been recovered is discharged into the atmosphere through another discharge line 104.

[0042] (Function and effect) Also in the combustion device system 20C and the ship 1 of the third embodiment above, as in the first embodiment, it is possible to achieve a good balance between the performance necessary for sufficiently processing nitrogen oxides and carbon dioxide and the scale of the device.

[0043] <Fourth Embodiment> Next, a fourth embodiment of the combustion device system and ship according to the present disclosure will be described. In the fourth embodiment described below, only the configuration of the combustion device system is different from the first embodiment, so the same parts as in the first embodiment will be denoted by the same reference numerals and described, and redundant descriptions will be omitted.

[0044] (Configuration of combustion device system) FIG. 6 is a diagram showing the configuration of a combustion device system according to a fourth embodiment of the present disclosure. As shown in FIG. 6, the combustion device system 20D includes the combustion device 8, an exhaust gas line 101, a discharge line 102, a recovery line 103, a supercharger 10, a processing device 21A, a carbon dioxide recovery device 25, and a denitration device 23.

[0045] In this fourth embodiment, the processing device 21A is disposed on the downstream side in the exhaust gas flow direction of the supercharger 10 in the exhaust gas line 101.

[0046] In such a combustion device system 20D, the exhaust gas from the combustion device 8 passes through the exhaust gas line 101, passes through the supercharger 10, and then is sent into the processing device 21A. In the processing device 21A, nitrogen oxides contained in the exhaust gas are processed. The exhaust gas passing through the processing device 21A is split into a discharge line 102 and a recovery line 103. The exhaust gas flowing into the discharge line 102 is directly discharged into the atmosphere.

[0047] On the other hand, the exhaust gas flowing into the recovery line 103 is sent into the denitration device 23. In the denitration device 23, nitrogen oxides contained in the exhaust gas passing through the processing device 21A are further processed. The exhaust gas passing through the denitration device 23 is sent into the carbon dioxide recovery device 25. In the carbon dioxide recovery device 25, carbon dioxide contained in the sent exhaust gas is recovered. The exhaust gas from which carbon dioxide has been recovered is discharged into the atmosphere through another discharge line 104.

[0048] (Operational effects) In the combustion device system 20D and the ship 1 of the fourth embodiment, as in the first embodiment, it is possible to achieve a good balance between the performance required for sufficiently treating nitrogen oxides and carbon dioxide and the device scale.

[0049] Further, in the fourth embodiment, the processing device 21A is disposed on the downstream side in the exhaust gas flow direction of the supercharger 10 in the exhaust gas line 101. Therefore, by additionally installing the processing device 21A on the downstream side in the exhaust gas flow direction with respect to the existing combustion device 8 equipped with the supercharger 10, and additionally installing the recovery line 103, the denitration device 23, and the carbon dioxide recovery device 25, the combustion device system 20D can be configured.

[0050] <Fifth Embodiment> Next, a fifth embodiment of the combustion device system and vessel according to the present disclosure will be described. In the fifth embodiment described below, only the configuration of the combustion device system differs from that of the first embodiment, so the same reference numerals are used for the same parts as in the first embodiment, and redundant explanations will be omitted.

[0051] (Configuration of the combustion device system) Figure 7 is a diagram showing the configuration of the combustion device system according to the fifth embodiment of the present disclosure. As shown in Figure 7, the combustion device system 20E includes the combustion device 8, an exhaust gas line 101, a discharge line 102, a recovery line 103, a turbocharger 10, a processing device 21A, a carbon dioxide recovery device 25, and a denitrification device 23.

[0052] In this fifth embodiment, the processing device 21A is provided in the discharge line 102.

[0053] In this combustion system 20E, exhaust gas from the combustion device 8 passes through the exhaust gas line 101 and the turbocharger 10, before being divided into a discharge line 102 and a recovery line 103. The exhaust gas that flows into the discharge line 102 is sent to the treatment device 21A. In the treatment device 21A, nitrogen oxides contained in the exhaust gas are treated. The exhaust gas that has passed through the treatment device 21A is released into the atmosphere.

[0054] The exhaust gas that flows into the recovery line 103 is sent to the denitrification unit 23. In the denitrification unit 23, nitrogen oxides contained in the exhaust gas are processed. The exhaust gas that has passed through the denitrification unit 23 is sent to the carbon dioxide recovery unit 25. In the carbon dioxide recovery unit 25, carbon dioxide contained in the exhaust gas that has been sent in is recovered. The exhaust gas from which carbon dioxide has been recovered is released into the atmosphere through another discharge line 104.

[0055] (Effects) In the combustion device system 20E and ship 1 of the fifth embodiment described above, a good balance can be achieved between the performance necessary to adequately treat nitrogen oxides and carbon dioxide and the scale of the device, similar to the first embodiment described above.

[0056] Furthermore, in the fifth embodiment described above, by providing the treatment device 21A in the discharge line 102, the amount of nitrogen oxides contained in the exhaust gas released into the atmosphere from the discharge line 102 can be reduced.

[0057] (Other Embodiments) Although embodiments of the present disclosure have been described in detail above with reference to the drawings, the specific configuration is not limited to these embodiments and may include design changes, etc., that do not depart from the gist of the present disclosure. In the above embodiments, urea was used as the reducing agent in the denitrification device 23 and the selective reduction catalyst device as the treatment device 21A, but ammonia may be used as the reducing agent. When ammonia is used as the reducing agent, carbon dioxide, which is produced when urea is used as the reducing agent, is not generated, so the amount of carbon dioxide recovered by the carbon dioxide recovery device 25 is reduced. In addition, the reducing agent is not limited to ammonia or urea, but other substances may be used.

[0058] In each of the above embodiments, the treatment devices 21A and 21B are provided, but a bypass line is provided to bypass the treatment devices 21A and 21B, so that the exhaust gas from the combustion device 8 is not treated by the treatment devices 21A and 21B depending on various operating conditions, etc. Alternatively, the treatment devices 21A and 21B may be omitted.

[0059] Furthermore, in the above embodiment, a burner or the like may be provided upstream of the denitrification device 23 to heat the exhaust gas sent to the denitrification device 23 and to promote the treatment of nitrogen oxides in the denitrification device 23.

[0060] Furthermore, in the above embodiment, heat exchangers may be provided in the discharge line 102 and other discharge lines 104 to recover the thermal energy contained in the exhaust gas released into the atmosphere.

[0061] Furthermore, in each of the above embodiments, the combustion device systems 20A to 20E are provided on the ship 1, but this is not limited to this. As long as a combustion device 8 is provided, the combustion device systems 20A to 20E may be provided on a floating body or a land-based facility.

[0062] <Note> The combustion apparatus systems 20A to 20E and the ship 1 described in each embodiment can be understood, for example, as follows.

[0063] (1) The combustion device systems 20A to 20E according to the first embodiment include: a combustion device 8 for burning fuel; an exhaust gas line 101 through which exhaust gas from the combustion device 8 flows; a discharge line 102 connected to the exhaust gas line 101 for releasing the exhaust gas from the exhaust gas line 101 into the atmosphere; a recovery line 103 branched off from the exhaust gas line 101; a carbon dioxide recovery device 25 connected to the recovery line 103 for recovering carbon dioxide contained in the exhaust gas from the exhaust gas line 101; and a denitrification device 23 provided upstream of the carbon dioxide recovery device 25 in the recovery line 103 for processing nitrogen oxides contained in the exhaust gas.

[0064] This suppresses the inclusion of nitrogen oxides in the carbon dioxide recovered by the carbon dioxide recovery unit 25. It also suppresses the nitrogen oxides contained in the exhaust gas from which carbon dioxide has been recovered. Furthermore, since the recovery line 103 is branched and connected to the exhaust gas line 101, a portion of the exhaust gas passing from the combustion unit 8 through the exhaust gas line 101 flows into the recovery line 103, where it is processed by the denitrification unit 23 and the carbon dioxide recovery unit 25, and the remainder of the exhaust gas is released into the atmosphere through the discharge line 102. For this reason, the denitrification unit 23 and the carbon dioxide recovery unit 25 do not need to process the entire amount of exhaust gas from the combustion unit 8, thus suppressing the need to increase the size of the denitrification unit 23 and the carbon dioxide recovery unit 25. Consequently, it becomes possible to have the denitrification unit 23 and the carbon dioxide recovery unit 25 on a scale appropriate to the required performance, making it easier to balance the required performance and size of the denitrification unit 23 and the carbon dioxide recovery unit 25. As a result, it is possible to provide combustion unit systems 20A to 20E that can achieve a good balance between the performance necessary to adequately treat nitrogen oxides and carbon dioxide and the size of the equipment.

[0065] (2) The combustion apparatus systems 20A to 20E according to the second embodiment are the combustion apparatus systems 20A to 20E of (1), further comprising treatment devices 21A and 21B arranged upstream of the denitrification device 23 in the flow direction of the exhaust gas, for treating nitrogen oxides contained in the exhaust gas from the combustion apparatus 8. Examples of treatment devices 21A and 21B include selective catalytic reduction (SCR) and exhaust gas recirculation (EGR).

[0066] As a result, by providing treatment devices 21A and 21B upstream of the denitrification device 23 in the direction of exhaust gas flow, nitrogen oxides contained in the exhaust gas from the combustion device 8 can be treated by treatment devices 21A and 21B, and then further treated by the denitrification device 23 downstream. Therefore, the amount of nitrogen oxides contained in the exhaust gas sent to the carbon dioxide recovery device 25 can be reduced even further.

[0067] (3) The combustion device systems 20A to 20D according to the third embodiment are the combustion device systems 20A to 20D of (2), wherein the treatment devices 21A to 21D are provided in the exhaust gas line 101.

[0068] With this configuration, by installing treatment devices 21A to 21D in the exhaust gas line 101 into which the entire amount of exhaust gas from the combustion device 8 flows, nitrogen oxides contained in the entire amount of exhaust gas from the combustion device 8 can be treated by the treatment devices 21A to 21D. Therefore, the amount of nitrogen oxides contained in the exhaust gas released into the atmosphere from the discharge line 102 can be reduced.

[0069] (4) The combustion apparatus system 20E according to the fourth embodiment is the combustion apparatus system 20E of (2), wherein the processing apparatus 21A is provided in the discharge line 102.

[0070] This makes it possible to reduce the amount of nitrogen oxides contained in the exhaust gas released into the atmosphere from the discharge line 102.

[0071] (5) The vessel 1 according to the fifth embodiment comprises a hull 2 ​​and one of the combustion device systems 20A to 20E from (1) to (4).

[0072] This makes it possible to provide a vessel 1 equipped with combustion system 20A to 20E that can strike a good balance between the performance necessary to adequately treat nitrogen oxides and carbon dioxide and the scale of the equipment.

[0073] The combustion system and vessels of this disclosure provide a good balance between the performance necessary for adequately treating nitrogen oxides and carbon dioxide and the scale of the equipment.

[0074] 1. Ship 2. Hull 3A, 3B. Sides 4. Bottom 5. Upper deck 6. Superstructure 8. Combustion system 9. Engine casing 10. Supercharger 20A-20E. Combustion system 21A, 21B. Treatment equipment 23. Denitrification system 25. Carbon dioxide recovery system 50. Control valve 101. Exhaust gas line 102. Discharge line 103. Recovery line 104. Discharge line 105. Return line

Claims

1. A combustion system comprising: a combustion device for burning fuel; an exhaust gas line through which exhaust gas from the combustion device flows; a discharge line connected to the exhaust gas line for releasing the exhaust gas from the exhaust gas line into the atmosphere; a recovery line branched off from the exhaust gas line; a carbon dioxide recovery device connected to the recovery line for recovering carbon dioxide contained in the exhaust gas from the exhaust gas line; and a denitrification device provided upstream of the carbon dioxide recovery device in the recovery line for processing nitrogen oxides contained in the exhaust gas.

2. The combustion apparatus system according to claim 1, further comprising a treatment device disposed upstream of the denitrification device in the flow direction of the exhaust gas, for treating nitrogen oxides contained in the exhaust gas from the combustion apparatus.

3. The combustion apparatus system according to claim 2, wherein the treatment apparatus is provided in the exhaust gas line.

4. The combustion apparatus system according to claim 2, wherein the processing apparatus is provided in the discharge line.

5. A vessel comprising a hull and a combustion system according to claim 1 or 2.

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