JP2017056381A - Desulfurization system and exhaust gas treatment equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a desulfurization system capable of improving desulfurization performance, and to provide exhaust gas treatment equipment.SOLUTION: A desulfurization system 40, which removes sulfur oxides from an exhaust gas exhausted out of a diesel engine 11, comprises a plurality of desulfurization reactors 41, 42 into which the exhaust gas flows to make sulfur oxides react with a desulfurization agent P2, a desulfurization agent feeder 46 that feeds the desulfurization agent P2 into the desulfurization reactors 41, 42, a first valve 41a and a second valve 42a capable of individually adjusting the flow rate of the exhaust gas introduced into the plurality of desulfurization reactors 41, 42, and a valve controller VC that controls the first valve 41a and the second valve 42a in accordance with the flow rate of the exhaust gas exhausted out of a diesel engine 11 to change the number of the desulfurization reactors 41, 42 that feed the exhaust gas.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a desulfurization system and an exhaust gas treatment apparatus.

  In a marine engine mounted on a marine vessel, a heavy fuel containing a large amount of sulfur is mainly used as a fuel. Exhaust gas discharged from marine engines contains harmful substances such as sulfur oxide (SOx), nitrogen oxide (NOx), and dust. These harmful substances cause air pollution. For this reason, the regulation is strengthened in the ship. A desulfurization system is installed to reduce sulfur oxides in the exhaust gas. As a desulfurization system for marine engines, a wet desulfurization system that performs desulfurization by gas-liquid contact in which a liquid that absorbs sulfur oxides is brought into contact with exhaust gas is known. Moreover, although it is a processing apparatus of the exhaust gas discharged | emitted from a waste combustion furnace instead of a ship, patent document 1 has described the dry-type desulfurization system.

Japanese Patent No. 3009926

  A wet desulfurization system requires wastewater treatment containing sulfur oxides. Moreover, since exhaust gas temperature falls, when performing catalytic denitration in a downstream, a heat exchange apparatus etc. are needed separately. Further, when a dry desulfurization system such as Patent Document 1 is mounted on a ship, further improvement is required in terms of desulfurization performance.

  The present invention has been made in view of the above, and an object of the present invention is to provide a desulfurization system and an exhaust gas treatment apparatus that can appropriately remove sulfur oxides from exhaust gas discharged from a marine engine.

  In order to achieve the above object, a desulfurization system of the present invention is a desulfurization system that removes sulfur oxide from exhaust gas discharged from a marine engine, and the exhaust gas flows in and reacts with the sulfur oxide and the desulfurization agent. A plurality of reactors, a desulfurizing agent supply unit for supplying a desulfurizing agent to the reactor, a flow rate adjusting unit capable of individually adjusting the flow rate of the exhaust gas introduced into the plurality of reactors, and the marine engine An adjustment amount control unit that controls the flow rate adjusting unit according to the flow rate of the exhaust gas to be discharged and changes the number of the reactors that supply the exhaust gas.

  Therefore, depending on the flow rate of the exhaust gas discharged from the marine engine, it is possible to switch between introducing the exhaust gas into one reactor or dispersing it into a plurality of reactors. Compared with the case where only one reactor is provided, the influence on the flow state of the exhaust gas flow rate change due to the load fluctuation in one reactor can be reduced. For this reason, it becomes easy to control the reactivity of the desulfurization agent in each reactor. Thereby, it becomes easy to maintain the state of each reactor so that the reactivity of the desulfurizing agent is high, so that the desulfurization performance can be improved.

  In the desulfurization system of the present invention, the adjustment amount control unit increases the number of the reactors that supply the exhaust gas as the flow rate of the exhaust gas discharged from the marine engine increases.

  Therefore, as the flow rate of the exhaust gas discharged from the marine engine increases, the number of reactors that supply the exhaust gas increases, and the influence of the exhaust gas flow rate change due to the load variation on the flow state can be suppressed to a small level.

  In the desulfurization system of the present invention, the reactor is a dry desulfurization reactor in which a fluid material that is solid particles and can flow when the exhaust gas has a predetermined flow rate is stored, and the desulfurization agent is solid particles Is.

  Therefore, when the exhaust gas introduced into the reactor flows through the inside of the reactor, a fluidized bed is formed by the fluidizing material inside the reactor, and the desulfurizing agent flows together with the fluidizing material. In this case, since the desulfurizing agent is in contact with the exhaust gas in a flowing state, the contact time of the desulfurizing agent with the exhaust gas becomes long, and sulfur oxides can be efficiently removed from the exhaust gas. Therefore, the desulfurization performance can be improved.

  In the desulfurization system of the present invention, the adjustment amount control unit supplies the exhaust gas when the flow rate of the exhaust gas discharged from the marine engine increases and the number of the reactors supplying the exhaust gas is increased. The amount of exhaust gas supplied to the reactor for newly supplying exhaust gas is increased while maintaining the flow rate of exhaust gas supplied to the reactor at a flow rate at which a fluidized bed is formed.

  Therefore, even when the number of reactors that supply exhaust gas is increased, it is possible to maintain a state in which the reactivity of the desulfurization agent is high in the reactor that is currently supplying exhaust gas.

  In the desulfurization system of the present invention, the adjustment amount control unit supplies the exhaust gas when the flow rate of the exhaust gas discharged from the marine engine increases and the number of the reactors supplying the exhaust gas is increased. The amount of the exhaust gas supplied to the reactor for newly supplying the exhaust gas is increased while the flow rate of the exhaust gas supplied to the reactor is decreased within the range of the flow rate at which the fluidized bed is formed.

  Therefore, while maintaining the state of high reactivity of the desulfurizing agent in the reactor currently supplying exhaust gas, the reactor of newly supplying exhaust gas can be brought into the state of high reactivity of desulfurizing agent.

  The desulfurization system of the present invention is disposed downstream of the reactor in the flow direction of the exhaust gas, separates the fluidizing material and the desulfurizing agent, supplies the fluidizing material to the reactor, and the desulfurizing agent. And a classifier for discharging the exhaust gas to the downstream side.

  Therefore, the desulfurizing agent after reacting with the sulfur oxide is flowed to the classifier by the exhaust gas together with the fluidizing material, for example, and discharged to the downstream side together with the exhaust gas by the classifier. In this case, it can suppress that the desulfurization agent after reaction stays in a dry-type desulfurization reactor. Moreover, since a fluidized material is supplied to a reactor, the loss of a fluidized material can be suppressed.

  The desulfurization system of the present invention includes a filter that is disposed downstream of the classifier in the flow direction of the exhaust gas and collects the desulfurization agent contained in the exhaust gas via the classifier.

  Therefore, since the desulfurizing agent is recovered from the exhaust gas by the filter, it can be suppressed that the desulfurizing agent is mixed into the exhaust gas and flows to the downstream side.

  In the desulfurization system of the present invention, the relationship between the average particle size of the fluidizing material and the average particle size of the desulfurizing agent satisfies 15 ≦ (average particle size of the fluidizing material / average particle size of the desulfurizing agent) ≦ 33. .

  Therefore, by setting the particle size ratio to 15 or more and 33 or less, it is possible to make the operation under a condition that a fluidized bed is formed during the operation of the ship at a higher time ratio. Moreover, by setting the particle size ratio to 15 or more and 33 or less, it is possible to appropriately form a fluidized bed with an operation load that needs to maintain high desulfurization performance.

  In the desulfurization system of the present invention, the plurality of reactors have the same volume and internal shape.

  Therefore, the flow state of the particulate matter in each container can be easily controlled by uniformly dispersing the exhaust gas in each container.

  An exhaust gas treatment apparatus according to the present invention is provided with the above desulfurization system and a denitration system that removes nitrogen oxides from the exhaust gas, which is provided on the downstream side of the exhaust gas flow direction with respect to the dry desulfurization reactor constituting the dry desulfurization system. An apparatus.

  Therefore, in addition to the effects of the above desulfurization apparatus, the catalyst of the denitration apparatus can be prevented from being deteriorated and the desulfurization performance can be maintained, so that an exhaust gas treatment apparatus with high exhaust gas treatment performance can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the desulfurization system and exhaust gas processing apparatus which can remove a sulfur oxide appropriately from the exhaust gas discharged | emitted from a marine engine can be provided.

FIG. 1 is a schematic configuration diagram illustrating an exhaust gas treatment apparatus according to the present embodiment. FIG. 2 is a diagram illustrating an example of a desulfurization system according to the present embodiment. FIG. 3 is a graph for explaining the flow state of the fluidized material. FIG. 4 is a graph showing the relationship between the load on the diesel engine and the change in the flow rate of exhaust gas per unit time introduced into the desulfurization reactor. FIG. 5 is a view showing a state where the second valve is closed in the desulfurization system. FIG. 6 is a diagram illustrating an example of a desulfurization reactor according to a modification. FIG. 7 is a graph showing the relationship between the load on the diesel engine and the change in the flow rate of exhaust gas per unit time introduced into the desulfurization reactor. FIG. 8 is a diagram illustrating a desulfurization system according to a modification.

  Hereinafter, embodiments of an exhaust gas treatment apparatus according to the present invention will be described with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a schematic configuration diagram illustrating an exhaust gas treatment apparatus according to the present embodiment. As shown in FIG. 1, the exhaust gas treatment device 10 includes a desulfurization system 40 and a denitration device 48. The exhaust gas treatment device 10 treats exhaust gas discharged from a diesel engine (marine engine) 11 that is mounted on a ship and used as a harmful substance in the exhaust gas, such as sulfur oxide (SOx), nitrogen oxide. (NOx), unburned components, dust, etc. are reduced or removed. In this case, the diesel engine 11 is used as a main engine or a power generation device of a ship.

  The diesel engine 11 is configured such that a scavenging trunk 13 is disposed on one side of a cylinder portion 12 and an exhaust manifold 14 is disposed on the other side. The cylinder portion 12 includes a plurality (six in this embodiment) of cylinders 21 arranged in series. Although not shown, each cylinder 21 is provided with a piston in a reciprocating manner in the vertical direction to form a combustion chamber. Each piston has a lower portion connected to the crankshaft.

  The scavenging trunk 13 is connected to each cylinder 21 of the cylinder portion 12 via an intake port 22. The exhaust manifold 14 is connected to each cylinder 21 of the cylinder portion 12 via an exhaust port 23, and an exhaust valve (not shown) is provided in each exhaust port 23. The scavenging trunk 13 is connected to the intake path L1, and the exhaust manifold 14 is connected to the exhaust path L2. The cylinder portion 12 is provided with an injector 24 for injecting fuel (for example, heavy oil) inside each cylinder 21, and each injector 24 is connected to a fuel tank (not shown).

  Therefore, the cylinder portion 12 is supplied with the fuel supplied from the injectors 24 to the combustion chamber and the combustion gas (for example, air) supplied from the scavenging trunk 13 via the intake ports 22, mixed and compressed. To burn. And each piston moves up and down by the energy generated by this combustion, and the crankshaft to which the lower end of each piston is connected is rotated. On the other hand, the exhaust gas generated by the combustion is discharged to the exhaust manifold 14 through the exhaust port 23.

  The diesel engine 11 is provided with an exhaust turbine supercharger 31. The exhaust turbine supercharger 31 is configured such that a compressor 32 and a turbine 33 are coaxially connected via a rotation shaft 34, and the compressor 32 and the turbine 33 can rotate integrally with the rotation shaft 34. The compressor 32 is connected to an intake path L3 for taking in air or the like from the outside and to an intake path L1 reaching the scavenging trunk 13. The turbine 33 is connected to an exhaust path L2 leading to the exhaust manifold 14, and is connected to an exhaust path L4 for exhausting to the outside. The intake passage L1 is provided with an air cooler 35 that cools the air compressed by the compressor 32.

  Therefore, the turbine 33 is driven by the exhaust gas (combustion gas) guided from the exhaust manifold 14 through the exhaust path L2, and after driving the compressor 32, the exhaust gas is discharged to the outside from the exhaust path L4. On the other hand, the compressor 32 is driven by the turbine 33 and compresses the air taken in from the intake path L3, and then pumps the compressed air from the intake path L1 to the scavenging trunk 13.

  The exhaust path (flow path) L4 discharges exhaust gas discharged from the exhaust manifold 14 and driving the turbine 33 to the outside. The exhaust gas treatment device 10 is provided on the downstream side of the exhaust gas flow direction from the exhaust path L4. As shown in FIG. 1, in the exhaust gas treatment device 10 of the present embodiment, a denitration device 48 is disposed between a classifier 43 and a bag filter 44 described later constituting the dry desulfurization system 40.

  FIG. 2 is a diagram illustrating an example of the desulfurization system 40 according to the present embodiment. As shown in FIGS. 1 and 2, the desulfurization system 40 is a so-called dry desulfurization system, and includes desulfurization reactors (reactors) 41 and 42, a classifier 43, a bag filter 44, a supply pipe 45, A desulfurization agent supply unit 46 and a desulfurization agent recovery unit 47 are provided. In the dry desulfurization system 40, desulfurization reactors 41 and 42, a classifier 43, and a bag filter 44 are provided in this order toward the downstream side in the exhaust gas flow direction. In FIG. 2, the denitration device 48 disposed between the classifier 43 and the bag filter 44 is not shown. Here, the dry desulfurization system is a flue gas desulfurization system that supplies a solid (particulate) desulfurization agent into exhaust gas and removes the desulfurization agent by reacting with sulfur oxide in the exhaust gas. Therefore, in the desulfurization system 40, water is not used for the reaction of the desulfurization agent, so that wastewater treatment containing sulfur oxide is not necessary. The desulfurization system 40 is distinguished from the following wet and semi-dry desulfurization systems. The wet desulfurization system is a flue gas desulfurization system that supplies exhaust gas to an aqueous solution layer or slurry layer in which a desulfurization agent is dissolved or dispersed, and reacts the desulfurization agent with sulfur oxide in the exhaust gas to remove it. Examples of the wet desulfurization system include an apparatus that performs processes such as a lime-gypsum method, a magnesium hydroxide method, and a soda method. The semi-dry type dry desulfurization system is a flue gas desulfurization system in which a slurry obtained by mixing a desulfurization agent and water is sprayed into exhaust gas, and the desulfurization agent is reacted with sulfur oxide to be removed. Examples of the semi-dry type desulfurization system include an apparatus that sprays slaked lime slurry into a spray dryer. The desulfurization system 40 is arranged in the order of desulfurization reactors 41 and 42, a classifier 43, and a bag filter 44 from the upstream side to the downstream side in the flow direction of the exhaust gas.

  As shown in FIG. 2, the desulfurization reactors 41 and 42 are connected in parallel to the exhaust path L4. Specifically, the exhaust path L4 is branched into an exhaust path L41 and an exhaust path L42. The desulfurization reactor 41 is connected to one exhaust path L41, and the desulfurization reactor 42 is connected to the other exhaust path L42.

  A first valve (flow rate adjustment unit) 41a is provided in the exhaust path L41. The first valve 41a adjusts the flow rate of the exhaust gas that flows through the exhaust path L41 and is introduced into the desulfurization reactor 41. The exhaust path L42 is provided with a second valve (flow rate adjusting unit) 42a. The second valve 42a adjusts the flow rate of the exhaust gas flowing through the exhaust path L42 and introduced into the desulfurization reactor 42.

  The opening degree of the first valve 41a and the second valve 42a is adjusted by a valve control unit (adjustment amount control unit) VC. The valve control unit VC can individually control the opening degree of the first valve 41a and the second valve 42a. The valve control unit VC controls the opening degree of the first valve 41a and the second valve 42a according to the flow rate of exhaust gas discharged from the diesel engine 11, for example. The flow rate of the exhaust gas can be calculated based on the oxygen concentration of the diesel engine 11 and the supply amount of fuel supplied to the combustion chamber (engine load).

  Further, the valve control unit VC can zero (close) the opening degree of the first valve 41a and the second valve 42a. When the first valve 41a is closed, no exhaust gas flows through the exhaust path L41, and no exhaust gas is introduced into the desulfurization reactor 41. Similarly, when the second valve 42a is closed, no exhaust gas flows through the exhaust path L42, and no exhaust gas is introduced into the desulfurization reactor 42.

  Subsequently, the desulfurization reactor 41 includes a casing 51 and a dispersion plate (supporting portion) 53. An exhaust gas inlet 52 and an exhaust gas outlet 54 are formed in the casing 51. The casing 51 is formed, for example, in a box shape, and the inside K is hollow. The exhaust gas inlet 52 is provided in the lower part of the housing 51, for example. The exhaust gas inlet 52 is connected to the exhaust path L4. The exhaust gas inlet 52 introduces the exhaust gas flowing through the exhaust path L4 into the interior K of the housing 51. The exhaust gas outlet 54 is provided in the upper part of the housing 51. The exhaust gas outlet 54 is connected to the exhaust path L5.

  The dispersion plate 53 is disposed in the interior K of the casing 51 so as to block the upper side of the exhaust gas inlet 52. By the dispersion plate 53, the interior K is divided into a chamber K1 and a flow part K2. The chamber K1 is formed below the dispersion plate 53. The flow part K2 is formed above the dispersion plate 53. The fluidized part K2 stores a granular material P containing a solid particulate fluidized material P1 and a desulfurizing agent P2.

  The fluidizing material P1 is solid particles and can flow when the exhaust gas has a predetermined flow rate. As the fluid material P1, for example, silica sand, dolomite, limestone, or the like is used. The average particle diameter of the fluidizing material P1 is set so as to form a fluidized bed by the flow of exhaust gas. Here, the average particle diameter is a 50% diameter value measured by a light diffraction scattering method using laser light in accordance with JIS Z 8825 using a particle size distribution measuring device.

  The desulfurizing agent P2 is formed into solid particles so as to flow together with the fluidizing material P1 by the flow of exhaust gas. The desulfurizing agent P2 reacts with the sulfur oxide contained in the exhaust gas, and removes the sulfur oxide from the exhaust gas. As the desulfurizing agent P2, for example, an alkali metal compound or an alkaline earth metal compound is used.

  Further, the dispersion plate 53 is formed in a porous shape so as to allow the exhaust gas to pass therethrough and not allow the particulate matter P to pass therethrough. Therefore, the dispersion plate 53 allows the exhaust gas introduced into the casing 51 from the exhaust gas inlet 52 to pass from the chamber K1 to the fluidizing portion K2 side, and the particulate matter P accommodated in the fluidizing portion K2 falls to the chamber K1 side. It prevents that.

  The desulfurization reactor 42 has the same configuration as the desulfurization reactor 41. Therefore, the desulfurization reactor 41 and the desulfurization reactor 42 have the same volume and internal shape. Although illustration and detailed description are omitted, the desulfurization reactor 42 has a casing 51, an exhaust gas inlet 52, a dispersion plate 53, and an exhaust gas outlet 54, similar to the desulfurization reactor 41. A chamber K1 and a flow part K2 are formed in K.

  The exhaust path L5 distributes the exhaust gas discharged from the desulfurization reactors 41 and 42 to the downstream side (the classifier 43 side).

  The classifier 43 is arranged downstream of the desulfurization reactors 41 and 42 in the exhaust gas flow direction. The classifier 43 is connected to the desulfurization reactors 41 and 42 via the exhaust path L5. The classifier 43 separates the fluidizing material P1 and the desulfurizing agent P2 contained in the exhaust gas. The classifier 43 collects the separated fluid P1 and supplies it to the desulfurization reactors 41 and 42, and discharges the desulfurization agent P2 and the exhaust gas downstream. As the classifier 43, for example, a cyclone is used. The classifier 43 includes an exhaust gas inlet 61, an exhaust gas outlet 62, and a fluid material recovery unit 63. The exhaust gas inlet 61 is connected to the exhaust path L5 and introduces exhaust gas from the desulfurization reactors 41 and 42. The exhaust gas outlet 62 is provided in the upper part of the classifier 43, and exhausts exhaust gas to the exhaust path L6. The fluidized material recovery unit 63 separates the fluidized material P1 from the exhaust gas, and discharges the separated fluidized material P1 to the supply pipe 45.

  The supply pipe 45 is connected to the classifier 43 and the desulfurization agent supply unit 46. The supply pipe 45 supplies the fluid P1 discharged from the classifier 43 to the desulfurization reactors 41 and 42. The supply pipe 44 supplies a desulfurization agent P2 supplied from a desulfurization agent supply unit 46 described later to the desulfurization reactors 41 and 42. The supply piping 45 has downcomers 45a and 45b. The downcomer 45a is connected to the flow part K2 of the desulfurization reactor 41. The downcomer 45 b is connected to the flow part K <b> 2 of the desulfurization reactor 42. The supply piping 45 supplies the granular material P to the fluidized part K2 of each desulfurization reactor 41 and 42 via the downcomers 45a and 45b. In addition, the fluidized material circulation part R is formed by the exhaust path L5, the exhaust gas inlet 61 and the fluidized material recovery part 63 of the classifier 43, the supply pipe 45, and the downcomers 45a and 45b. The fluidizing material circulation part R is a path for circulating the fluidizing material P1 contained in the exhaust gas discharged from the fluidizing part K2 of the desulfurization reactors 41 and 42 to the fluidizing part K2 of the desulfurization reactors 41 and 42, respectively.

  The desulfurization agent supply unit 46 supplies the desulfurization agent P <b> 2 to the supply pipe 45. The desulfurization agent supply unit 46 includes a supply amount adjustment unit 46a. The supply amount adjusting unit 46 a adjusts the supply amount of the desulfurizing agent P <b> 2 according to the flow rate of exhaust gas discharged from the diesel engine 11. In addition, as the value of the flow rate of the exhaust gas, the oxygen concentration of the diesel engine 11 and the supply amount of the fuel supplied to the combustion chamber are set as in the case of setting the average particle size (Archimedes number) of the fluid P1. A value calculated based on this can be used. For example, a flow rate adjusting valve may be provided as the supply amount adjusting unit 46a.

  The bag filter 44 is connected to the classifier 43 via the exhaust path L6, the denitration device 48, and the exhaust path L7. Since the denitration device 48 is disposed between the classifier 43 and the bag filter 44, the dry desulfurization system 40 has the bag filter 44 disposed downstream of the denitration device 48 in the exhaust gas flow direction. For this reason, for example, the bag filter 44 having a heat resistant temperature lower than the exhaust gas temperature required for the denitration in the denitration device 48 can be used. For example, when the bag filter 44 having a heat resistance higher than the exhaust gas temperature required for denitration in the denitration device 48 is used, the bag filter 44 is arranged upstream of the denitration device 48 in the exhaust gas flow direction. May be. The bag filter 44 reduces or removes unburned components and dust in the exhaust gas and discharges the exhaust gas to the exhaust path L7. The bag filter 44 has an exhaust gas inlet 71, a filter part 72, and an exhaust gas outlet 73. The exhaust gas inlet 71 is connected to the exhaust path L6 and introduces exhaust gas. The filter unit 72 captures unburned components and dust in the exhaust gas. The filter unit 72 captures the desulfurization agent P2 from the exhaust gas introduced into the bag filter 44. The exhaust gas outlet 73 is connected to the exhaust path L <b> 7 and exhausts the exhaust gas via the filter unit 72.

  In addition, the bag filter 44 is provided with a desulfurization agent recovery unit 47. The desulfurization agent recovery unit 47 recovers the desulfurization agent P2 captured by the filter unit 72, for example. The desulfurization agent recovery unit 47 includes a receiving unit 74, a pipe 75, and a tank unit 76. The receiving part 74 receives the desulfurization agent P2 captured and dropped by the filter part 72. The pipe 75 connects the receiving portion 74 and the tank portion 76, and sends the desulfurizing agent P <b> 2 that has dropped to the receiving portion 74 to the tank portion 76. The tank unit 76 stores the desulfurizing agent P2 sent through the pipe 75.

  Further, as shown in FIG. 1, the denitration device 48 is disposed between the classifier 43 and the bag filter 44, and reduces or removes nitrogen oxides in the exhaust gas sent from the exhaust path L6, thereby removing the exhaust gas. Is discharged to the exhaust path L7.

  Further, the exhaust gas treatment device 10 has an exhaust gas recirculation path L9 for returning the exhaust gas to the scavenging trunk 13. The exhaust gas recirculation path L9 connects between the exhaust path L8 and the intake path L3. The exhaust gas recirculation path L9 is provided with a flow rate adjusting valve 50 for adjusting the amount of exhaust gas introduced. The compressor 32 compresses the mixed gas of the air sucked from the intake path L3 and the exhaust gas recirculation gas introduced from the exhaust gas recirculation path L9.

  Next, the operation of the exhaust gas treatment apparatus 10 will be described. As shown in FIG. 1, exhaust gas generated by combustion in the diesel engine 11 is discharged to the exhaust manifold 14 through the exhaust port 23 and is discharged to the exhaust path L2. The exhaust gas is introduced into the exhaust turbine supercharger 31, and after exhausting the turbine 33 and the compressor 32, the exhaust gas is discharged to the exhaust path L4. Further, the air taken into the compressor 32 from the intake path L3 is compressed by the compressor 32 and is pumped to the scavenging trunk 13 from the intake path L1 as combustion gas. The diesel engine 11 gradually increases the load from the start of operation (load 0%), and operates with a load of 100% after a predetermined time has elapsed. As the load on the diesel engine 11 increases, the flow rate per unit time of the exhaust gas discharged from the diesel engine 11 increases.

  The exhaust gas discharged to the exhaust path L4 is introduced into the desulfurization system 40. This exhaust gas is introduced into the desulfurization reactors 41 and 42 from the exhaust paths L41 and L42 according to the opening degree of the first valve 41a and the second valve 42a. The valve control unit VC adjusts the opening degree of the first valve 41 a and the second valve 42 a according to the flow rate of exhaust gas per unit time, that is, the load of the diesel engine 11. Hereinafter, an example of opening control of the first valve 41a and the second valve 42a by the valve control unit VC will be described. The opening degree control of the valve control unit VC is not limited to the following description.

  FIG. 4 is a graph showing the relationship between the load on the diesel engine 11 and the change in the flow rate of the exhaust gas per unit time introduced into each of the desulfurization reactors 41 and 42. In the following, the flow rate of exhaust gas per unit time introduced into the desulfurization reactor 41 is referred to as “first flow rate”, and the flow rate of exhaust gas per unit time introduced into the desulfurization reactor 42 is referred to as “second flow rate”. ". Further, the load of the diesel engine 11 is simply expressed as “load”. In the following description, the diesel engine 11 is a small engine with an output of 10 MW, for example.

  As shown in FIG. 4, exhaust gas is introduced only into the desulfurization reactor 41 until the load reaches 60% after the diesel engine 11 is started. Therefore, the valve control unit VC keeps the second valve 42a closed until the load reaches 60%. FIG. 5 is a view showing a state where the second valve 42 a is closed in the desulfurization system 40. As shown in FIG. 5, when only the first valve 41a is opened, the exhaust gas that has reached the exhaust path L4 does not flow to the exhaust path L42 but flows only to the exhaust path L41.

  In the period from the start of the diesel engine 11 until the load reaches 60%, the valve controller VC adjusts the opening of the first valve 41a so that the first flow rate increases in proportion to the load. In this case, the valve control unit VC adjusts the opening degree of the first valve 41a so that the fluidized material P1 of the desulfurization reactor 41 forms a circulating fluidized bed before the load reaches, for example, 40%.

  Specifically, the valve control unit VC adjusts the opening degree of the first valve 41a so that the first flow rate is larger than the threshold value α1 and smaller than the threshold value α2 shown in FIG. Here, the threshold value α1 is a lower limit value of the exhaust gas flow rate necessary for the fluidizing material P1 to form a circulating fluidized bed in the desulfurization reactor 41 (and the desulfurization reactor 42). When the first flow rate is lower than the threshold value α1, the fluidizing material P1 of the desulfurization reactor 41 (and the desulfurization reactor 42) does not form a circulating fluidized bed but forms a fixed bed or a bubble fluidized bed. The threshold α2 is an upper limit value of the exhaust gas flow rate necessary for the fluidizing material P1 to form a circulating fluidized bed in the desulfurization reactor 41 (and the desulfurization reactor 42). When the first flow rate exceeds the threshold value α2, the fluidized material P1 of the desulfurization reactor 41 (and the desulfurization reactor 42) is scattered without forming a circulating fluidized bed.

  After the load reaches 60%, the introduction of exhaust gas is started also to the desulfurization reactor 42. That is, the flow rate of exhaust gas discharged from the diesel engine 11 increases, and the number of desulfurization reactors that supply exhaust gas is increased. In this case, the flow rate of the exhaust gas supplied to the desulfurization reactor 41 that is currently supplying the exhaust gas is maintained at the flow rate at which the fluidized bed (circulating fluidized bed) is formed, and the desulfurization reactor 42 that newly supplies the exhaust gas. Increase the amount of exhaust gas to be supplied. In this case, the amount of the exhaust gas supplied to the desulfurization reactor 42 is increased while the flow rate of the exhaust gas supplied to the desulfurization reactor 41 is decreased within the range of the flow rate at which the fluidized bed is formed. Specifically, the valve control unit VC decreases the opening of the first valve 41a so that the value of the first flow rate decreases to a value equal to, for example, a value at a load of 40%. In this case, since the first flow rate exceeds the threshold value α1, the desulfurization reactor 41 maintains the state where the circulating fluidized bed is formed. Then, the valve control unit VC opens the second valve 42a simultaneously with the decrease in the opening degree of the first valve 41a, and causes the desulfurization reactor 42 to start introducing the exhaust gas. At this time, the valve control unit VC adjusts the opening degree of the second valve 42a so that the second flow rate becomes about half of the first flow rate.

  After the load reaches 60% and the opening adjustment of the first valve 41a and the second valve 42a is performed, the valve control unit VC keeps the value of the first flow rate until the load reaches 80%. Thus, the opening degree of the first valve 41a is kept constant. On the other hand, the valve controller VC gradually increases the opening degree of the second valve 42a so that the value of the second flow rate becomes equal to the first flow rate when the load reaches 80%.

  After the load reaches 80% and the first flow rate and the second flow rate become equal, the valve controller VC determines that the first flow rate and the second flow rate exceed the threshold value α2 until the load reaches 100%. The opening degree of the first valve 41a and the second valve 42a is adjusted so as to increase at an equal rate within a range that is not present. By adjusting the opening degree of the first valve 41 a and the second valve 42 a in this way, the exhaust gas is dispersedly introduced into the desulfurization reactor 41 and the desulfurization reactor 42.

  Subsequently, in the desulfurization reactor 41, the exhaust gas is introduced into the chamber K <b> 1 from the exhaust gas inlet 52 and is introduced into the fluidizing portion K <b> 2 through the dispersion plate 53. Similarly, in the desulfurization reactor 42, the exhaust gas is introduced into the chamber K <b> 1 from the exhaust gas inlet 52 and is introduced into the fluidizing portion K <b> 2 through the dispersion plate 53. Then, the exhaust gas introduced into the fluidized portions K2 of the desulfurization reactors 41 and 42 flows upward and is discharged from the exhaust gas outlet 54 to the exhaust path L5.

  The exhaust gas discharged to the exhaust path L5 is discharged to the exhaust path L6 via the classifier 43 and introduced into the bag filter 44. The exhaust gas introduced into the bag filter 44 is removed by the filter unit 72 and is discharged to the exhaust path L7. In this way, the exhaust gas passes through the desulfurization system 40.

  At this time, in the desulfurization reactors 41 and 42, the flowing material P1 supported by the dispersion plate 53 is fluidized by supplying exhaust gas. Further, the fluidizing material P1 fluidizes the desulfurizing agent P2 together with the fluidizing material P1. For example, the fluid P1 floats due to the flow of exhaust gas at the first flow rate or the second flow rate, and is discharged from the exhaust gas outlet 54 to the exhaust path L5 together with the exhaust gas. The fluid material P1 discharged to the exhaust path L5 is separated from the exhaust gas by the classifier 43, and is discharged from the fluid material recovery unit 63 to the supply pipe 45. Since the fluidizer P1 is reliably separated from the exhaust gas by the classifier 43, the fluidizer P1 is prevented from flowing to the downstream side while the fluidizer P1 is mixed in the exhaust gas. Then, the fluid P1 is supplied from the supply pipe 45 to the fluidizing portions K2 of the desulfurization reactors 41 and 42 together with the desulfurization agent P2 via the downcomers 45a and 45b. Since the fluidizing material P1 and the desulfurizing agent P2 are mixed and supplied to the fluidizing portion K2, the fluidizing material P1 or the desulfurizing agent P2 is prevented from being unevenly distributed in the granular material P. Thus, the fluidized material P1 is fluidized from the fluidized portions K2 of the desulfurization reactors 41 and 42 to the fluidized portions K2 via the exhaust passage L5, the classifier 43, and the supply pipe 45 (downcomer 44a). Circulate the circulation part R. Therefore, the circulating fluidized bed S (see FIG. 2) of the fluidized material P1 is formed in the desulfurization system 40.

  In the desulfurization system 40, the fluidized material P <b> 1 and the desulfurization agent P <b> 2 float together with the flow of exhaust gas and flow in the circulating fluidized bed S. The desulfurization agent P2 fluidized in the dry reactor 41 contacts the exhaust gas and reacts with the sulfur oxide contained in the exhaust gas. Thereby, the sulfur oxide contained in exhaust gas is removed.

  The desulfurization system 40 passes through the desulfurization reactors 41 and 42, and the exhaust gas from which sulfur oxide has been removed flows into the classifier 43. Further, in the desulfurization system 40, a part of the fluidized material P <b> 1 and the desulfurization agent P <b> 2 of the desulfurization reactors 41 and 42 flows into the classifier 43 together with the exhaust gas. The fluidizing material P1 and the desulfurizing agent P2 flowing into the classifier 43 are separated by the classifier 43 from the exhaust gas. Further, the desulfurizing agent P2 is separated from the exhaust gas in a state where a part of the desulfurizing agent P2 adheres to the fluidizing material P1, and a part of the desulfurizing agent P2 is conveyed to the downstream side together with the exhaust gas. That is, a part of the desulfurizing agent P2 is separated from the fluidized material P1, and is discharged from the exhaust gas outlet 62 to the exhaust gas path L6 together with the exhaust gas, not the circulating path.

  The exhaust gas discharged to the exhaust path L6 is introduced into the denitration device 48 disposed on the downstream side. The denitration device 48 reduces or removes nitrogen oxides contained in the introduced exhaust gas and discharges it to the exhaust path L7. In the dry desulfurization system 40, the exhaust gas flowing into the exhaust passage L7 passes through the bag filter 44. As for the exhaust gas, the foreign matter and the desulfurization agent P2 flowing together with the exhaust gas are collected (captured) by the bag filter 44. In the dry desulfurization system 40, the exhaust gas flowing into the exhaust passage L7 after passing through the denitration device 48 passes through the bag filter 44. Therefore, even when the heat resistance temperature of the bag filter 44 is lower than the temperature required for denitration in the denitration device 48. Fully usable. The desulfurization agent P <b> 2 captured by the filter unit 72 is collected in the tank unit 76 via the receiving unit 74 and the pipe 75. The dry desulfurization system 40 discharges the exhaust gas that has passed through the bag filter 44 to the exhaust path L8.

  The dry desulfurization system 40 supplies the desulfurization agent P <b> 2 from the desulfurization agent supply unit 46 to the supply pipe 45. As a result, the dry desulfurization system 40 is replenished with the desulfurization agent P2 being discharged from the fluidized portion K2 by the exhaust gas and the number of the desulfurizing agents P2 in the fluidized portion K2 being reduced. Further, the dry desulfurization system 40 adjusts the amount of the desulfurizing agent P2 supplied from the supply amount adjusting unit 45 according to the flow rate of the exhaust gas.

  As described above, the desulfurization system 40 of the present embodiment introduces the exhaust gas into one desulfurization reactor 41 or a plurality of desulfurization reactors 42 and 42 according to the flow rate of the exhaust gas discharged from the diesel engine 11. As compared with the case where only one desulfurization reactor is provided, the influence on the flow state of the exhaust gas flow rate change due to load fluctuations in one desulfurization reactor is possible. Can be reduced. For this reason, control of the reactivity of the desulfurization agent P2 in each desulfurization reactor 41 and 42 becomes easy. Thereby, since it becomes easy to maintain the state of each desulfurization reactor 41 and 42 so that the reactivity of the desulfurization agent P2 may be high, the desulfurization performance can be improved.

  For example, when there is only one desulfurization reactor, the flow rate of exhaust gas per unit time flowing into the desulfurization reactor in the state of 100% load is the sum of the first flow rate and the second flow rate shown in FIG. (Relative value). Further, it is assumed that the variation of the exhaust gas flow rate is at least 0 and 15 (relative value). In addition, when there is only one desulfurization reactor, the flow rate of the exhaust gas per unit time cannot be adjusted with a valve or the like, and depends on the fluctuation of the load. For this reason, the range of the load in which the circulating fluidized bed can be formed in the desulfurization reactor is fixed, and the flexible control according to the variation of the load becomes difficult.

  On the other hand, when two desulfurization reactors 41 and 42 are provided as in the present embodiment, the first flow rate and the second flow rate are 7.5 (relative values) in a state where the load is 100%, as shown in FIG. One by one. Further, the variations in the first flow rate and the second flow rate are also in the range of 0 to 9.5 (relative value). As described above, by providing a plurality of desulfurization reactors, variation in the flow rate of the exhaust gas introduced into one desulfurization reactor 41 and 42 is reduced. Moreover, the opening degree of the first valve 41a and the second valve 42a can be adjusted by the valve control unit VC. Therefore, as shown in FIG. 4, for example, the first flow rate is changed according to the fluctuation of the load so that the circulating fluidized bed is formed in the desulfurization reactors 41 and 42 from the state where the load is 40% to the state where the load is 100%. The second flow rate can be flexibly controlled. Thereby, the influence on the flow state of the exhaust gas flow rate change due to the load fluctuation can be suppressed to a small level.

  Further, in the desulfurization reactors 41 and 42, the maximum values of the first flow rate and the second flow rate are smaller than when only one desulfurization reactor is provided. For this reason, the size of the desulfurization reactors 41 and 42 can be reduced. In addition, since the size per one of the desulfurization reactors 41 and 42 is reduced, the degree of freedom in designing the arrangement of the desulfurization reactors 41 and 42 is increased. Thereby, the space can be effectively used.

  Further, by supplying a new desulfurization agent P2 to the dry desulfurization reactor 41, the state where the unreacted desulfurization agent P1 is disposed in the dry desulfurization reactor 41 can be maintained. As a result, it is possible to improve the desulfurization performance. Moreover, according to this embodiment, since the circulating fluidized bed S is formed in the desulfurization reactor 41 by the flow of exhaust gas, there is no loss of the fluid P1, and the dry desulfurization system 40 with high reactivity is obtained.

  Further, the desulfurization agent P2 separated from the fluid P1 by the classifier 43 is discharged to the downstream side together with the exhaust gas, so that sulfur oxides in the exhaust gas can be removed while flowing with the exhaust gas. Thereby, the flow path of the exhaust gas that can be desulfurized can be lengthened, and sulfur oxides in the exhaust gas can be suitably removed (reduced). Further, since the desulfurization agent P2 after the reaction can be separated by the classifier 43, it is possible to suppress the desulfurization agent P2 after the reaction from remaining in the desulfurization reactors 41 and 42.

  In the dry desulfurization system 40, the desulfurization agent P2 captured by the bag filter 44 also reacts with the sulfur oxide in the exhaust gas through which the unreacted component passes. As a result, the desulfurization agent P2 captured by the bag filter 44 can also remove sulfur oxides in the exhaust gas. Thereby, the flow path of the exhaust gas that can be desulfurized can be made longer, and sulfur oxides in the exhaust gas can be suitably removed (reduced).

  Moreover, since the desulfurization system 40 which concerns on this embodiment is a dry-type desulfurization system, it does not need the waste water treatment containing a sulfur oxide, for example. Further, the desulfurization system 40 can discharge to the exhaust path L6 without reducing the temperature of the exhaust gas. At least when performing catalytic denitration downstream of the desulfurization reactors 41 and 42, equipment such as a heat exchanger is provided. There is no need to provide it separately. Thereby, size reduction and space saving of the desulfurization system 40 and the exhaust gas treatment apparatus 10 can be achieved.

  Here, fluidization of the fluid P1 in the desulfurization reactor 41 will be described in more detail. When the exhaust gas does not flow, the fluidizing material P1 is in a state of being deposited as a fixed layer on the dispersion plate 53. On the other hand, as the exhaust gas is introduced into the casing 51 and the exhaust gas increases from the dispersion plate 53 to the fluidized portion K2, the fluid P1 starts to flow and forms a fluidized bed. Examples of such a fluidized bed include a bubble fluidized bed and a circulating fluidized bed. The bubble type fluidized bed is a fluidized bed in which bubbles are formed by exhaust gas inside. The circulating fluidized bed is a fluidized bed in which the fluidized material P1 is suspended by the exhaust gas and the suspended fluidized material P1 is circulated by a classifier or the like. When the circulating fluidized bed is formed, the fluidized material P1 needs to be suspended and circulated, so that the fluidity of the fluidized material P1 needs to be higher than that of the bubble fluidized bed. If the fluidity of the fluidizing material P1 is too high, the fluidizing material P1 is scattered with the exhaust gas, and a fluidized bed (circulating fluidized bed) is not formed.

  FIG. 3 is a graph for explaining the flow state of the fluid P1. The horizontal axis of the graph represents Archimedes number (Ar), and the vertical axis of the graph represents Reynolds number (Re). The graph of FIG. 3 is a log-log graph.

  As parameters for determining the flow state of the fluid P1, there are, for example, Archimedes number and Reynolds number which are dimensionless parameters. The Archimedes number is determined by the average particle diameter of the fluidized material P1 in the fluidized bed. The Reynolds number is determined by the flow rate of exhaust gas per unit time supplied to the fluidized bed. The flow rate of the exhaust gas can be calculated based on the oxygen concentration of the diesel engine 11 and the amount of fuel supplied to the combustion chamber (engine load).

  A curve 102 in the graph of FIG. 3 shows the Reynolds number in a state where particles are infinitely linked. The curve 104 in the graph of FIG. 3 shows the Reynolds number on a single particle weekend speed basis. As shown in FIG. 3, when the Archimedes number and Reynolds number of the fluidized material P1 are values within the shaded area 106 surrounded by the curve 102 and the curve 104 of the graph, the fluidized part K2 has a circulating fluidized bed. Can be formed.

  On the other hand, for example, when the Archimedes number is constant, when the Reynolds number is a value above the region 106 (when the gas flow rate per unit time is too large), the fluid P1 is scattered with the exhaust gas. . In addition, when the Reynolds number is a value lower than the region 106 (when the gas flow rate per unit time is too small), a bubble type fluidized bed or a fixed bed is formed.

  For example, when the Reynolds number is constant and the Archimedes number is a value on the left side of the region 106 (when the average particle diameter of the fluid P1 is too small), the fluid P1 is scattered with the exhaust gas. It becomes. When the Archimedes number is a value on the right side of the region 106 (when the average particle diameter of the fluid P1 is too large), a bubble fluidized bed or a fixed bed is formed.

  Thus, when Archimedes number and Reynolds number become the value of the area | region above the area | region 106, it will be in the state which the fluidized material P1 scatters with waste gas. When the Archimedes number and the Reynolds number are values in the lower region of the region 106, a bubble-type fluidized bed or a fixed bed is formed.

  In the present embodiment, the Reynolds number is set according to the load of the diesel engine 11. Therefore, when the circulating fluidized bed is formed using the fluidized material P1, the Archimedes number corresponding to the Reynolds number (load of the diesel engine 11) is set so that the Archimedes number and the Reynolds number of the fluidized material P1 become values in the region 106. What is necessary is just to set (average particle diameter of the fluidized material P1).

  Furthermore, in order to form a circulating fluidized bed in the fluidized part K2 of the casing 51, it is necessary to consider the height of the fluidized part K2. In this case, as the Reynolds number increases, that is, as the flow rate of exhaust gas per unit time increases, it is necessary to increase the height of the casing 51 so that the fluid P1 does not scatter. Since the housing | casing 51 is provided in a ship, it is calculated | required that height does not become high too much. For this reason, when the Reynolds number becomes large, for example, when the value is 15 or more, the Archimedes number (average particle diameter of the fluid P1) is set so that the height of the casing 51 does not become too high. Good. In addition, when fluidizing the fluid P1, the average particle size of the fluid P1 may be reduced due to wear. Therefore, the Archimedes number (average particle diameter of the fluidized material P1) may be set in consideration of the reduction of the particle diameter due to such wear.

  Here, the particle size ratio of the fluidizing material P1 and the desulfurizing agent P2 (average particle size of the fluidizing material P1 / average particle size of the desulfurizing agent P2) can be set to be 15 or more and 33 or less, for example. However, the present invention is not limited to this. By setting the particle size ratio to 15 or more and 33 or less, it is possible to make the operation under a condition that a fluidized bed is formed during the operation of the ship at a higher time ratio. Moreover, by setting the particle size ratio to 15 or more and 33 or less, it is possible to appropriately form a fluidized bed with an operation load that needs to maintain high desulfurization performance. Further, for example, by setting the particle size ratio to 15 or more, the range of the load in which the circulating fluidized bed S can be formed can be widened. Therefore, even if the load of the diesel engine 11 changes, the circulating fluidized bed S Can be suitably formed. For example, by setting the particle size ratio to 15 or more, the circulating fluidized bed S can be suitably formed even when the fluidized material P1 is worn and the average particle size of the fluidized material P1 is reduced.

  Further, in the dry desulfurization system 40, the desulfurization agent P2 floats together with the fluidizing material P1 by the flow of exhaust gas, and flows in the circulating fluidized bed S. Thus, since the desulfurization agent P2 floats and the dry desulfurization system 40 flows through the circulating fluidized bed S, the contact time of the desulfurization agent P2 with respect to the exhaust gas becomes long, and sulfur oxides can be efficiently removed from the exhaust gas. it can.

  The technical scope of the present invention is not limited to the above-described embodiment, and appropriate modifications can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, in the desulfurization system 40, the case where the first valve 41a and the second valve 42a operate with the same opening degree is described as an example, but the present invention is not limited thereto. Alternatively, the state where one of the valves is closed may be continued.

  For example, when an inspection, repair, replacement or the like is performed on one of the desulfurization reactors 41 and 42 (here, the desulfurization reactor 42 is taken as an example), the desulfurization reactor 42 is closed by closing the second valve 42a. It is possible to shut off the exhaust gas. As a result, the operator can easily treat the desulfurization reactor 42.

  In the above-described embodiment, the desulfurization reactors 41 and 42 have the same configuration, and the volume and the internal shape are described as examples. However, the present invention is not limited to this, and the volume and internal shape of the desulfurization reactors 41 and 42 are the same. At least one of them may be different. FIG. 6 is a diagram illustrating an example of the desulfurization reactors 81 and 82 according to the modification. As in the desulfurization system 40A shown in FIG. 6, the volume V1 of one desulfurization reactor (for example, desulfurization reactor 81) is larger than the volume V2 of the other desulfurization reactor (for example, desulfurization reactor 82). Yes. The desulfurization reactors 81 and 82 differ from the desulfurization reactors 41 and 42 only in volume, and the other configurations are the same as the desulfurization reactors 41 and 42.

  FIG. 7 is a graph showing the relationship between the load of the diesel engine 11 and the change in the flow rate of exhaust gas per unit time introduced into each of the desulfurization reactors 81 and 82. In the following, the flow rate of exhaust gas per unit time introduced into the desulfurization reactor 81 is referred to as “third flow rate”, and the flow rate of exhaust gas per unit time introduced into the desulfurization reactor 82 is referred to as “fourth flow rate”. ". Further, the load of the diesel engine 11 is simply expressed as “load”. In the following description, it is assumed that the volume ratio V1: V2 between the desulfurization reactor 81 and the desulfurization reactor 82 is 2: 1. In the following description, the diesel engine 11 is a small engine with an output of 10 MW, for example.

  As shown in FIG. 7, after the diesel engine 11 is started, exhaust gas is introduced only into the desulfurization reactor 41 until the load reaches 60%. Therefore, the valve control unit VC keeps the second valve 42a closed until the load reaches 60%. FIG. 5 is a diagram showing the state of the first valve 41a and the second valve 42a at this time. As shown in FIG. 5, when only the first valve 41a is opened, the exhaust gas that has reached the exhaust path L4 does not flow to the exhaust path L42 but flows only to the exhaust path L41.

  Further, during the period from the start of the diesel engine 11 until the load reaches 60%, the valve control unit VC adjusts the opening degree of the first valve 41a so that the third flow rate increases in proportion to the load. In this case, the valve control unit VC adjusts the opening degree of the first valve 41a so that the fluidized material P1 of the desulfurization reactor 81 forms a circulating fluidized bed before the load reaches, for example, 50%.

  Specifically, the valve control unit VC adjusts the opening degree of the first valve 41a so that the third flow rate is larger than the threshold value β1 shown in FIG. 5 and smaller than the threshold value β2. Here, the threshold value β1 is a lower limit value of the exhaust gas flow rate necessary for the fluidizing material P1 to form a circulating fluidized bed in the desulfurization reactor 81. The threshold value β2 is an upper limit value of the exhaust gas flow rate necessary for the fluidizing material P1 to form a circulating fluidized bed in the desulfurization reactor 81.

  After the load reaches 60%, introduction of the exhaust gas is started also to the desulfurization reactor 82. The valve control unit VC decreases the opening degree of the first valve 41a so that the value of the third flow rate decreases to a value equal to, for example, the value at the time of 50% load. Then, the valve control unit VC opens the second valve 42a simultaneously with the decrease in the opening degree of the first valve 41a, and causes the desulfurization reactor 82 to start introducing the exhaust gas. At this time, the valve control unit VC adjusts the opening degree of the second valve 42a so that the fourth flow rate becomes a value of about a quarter of the third flow rate.

  After the load reaches 60% and the opening adjustment of the first valve 41a and the second valve 42a is performed, the valve control unit VC keeps the value of the third flow rate until the load reaches 80%. Thus, the opening degree of the first valve 41a is kept constant. On the other hand, the valve control unit VC gradually increases the opening degree of the second valve 42a, and when the load reaches 80%, the value of the fourth flow rate is larger than the threshold value γ1 and does not exceed the threshold value γ2. To be. Here, the threshold value γ1 is a lower limit value of the exhaust gas flow rate necessary for the fluidizing material P1 to form a circulating fluidized bed in the desulfurization reactor 82. The threshold value γ2 is an upper limit value of the exhaust gas flow rate necessary for the fluidizing material P1 to form a circulating fluidized bed in the desulfurization reactor 82. In FIG. 7, for example, the value of the fourth flow rate is set to be about half of the third flow rate.

  After the load reaches 80% and the third flow rate and the fourth flow rate become equal, the valve control unit VC has a ratio of the third flow rate and the fourth flow rate of 2: 1 until the load reaches 100%. The degree of opening of the first valve 41a and the second valve 42a is adjusted so as to rise at the same time. Note that the third flow rate may exceed the threshold value β2 and the fourth flow rate may exceed the threshold value γ2 before the load reaches 100%. Therefore, as shown in FIG. 7, when the third flow rate and the fourth flow rate rise at a ratio of 2: 1, the valve control unit VC sets β2 and γ2 as much as possible for both the third flow rate and the fourth flow rate. In order not to exceed, the rising start position of each flow rate may be shifted when the load reaches 80%. In FIG. 7, the third flow rate is increased by about 1 (relative value) and the fourth flow rate is decreased by about 0.5 (relative value).

  Thus, by adjusting the opening degree of the first valve 41a and the second valve 42a, a circulating fluidized bed is formed in the desulfurization reactor 81 and the desulfurization reactor 82 within a practical load range of 40% to 80%. It becomes possible to do. Thereby, desulfurization system 40A with high desulfurization performance is obtained.

  The desulfurization systems 40 and 40A may include an exhaust gas circulation path that circulates and supplies exhaust gas via the classifier 43 to the exhaust path L4 in addition to the configuration of the above embodiment. FIG. 8 is a view showing a desulfurization system 40B according to a modification. As shown in FIG. 8, the desulfurization system 40B has an exhaust gas circulation path (exhaust gas circulation part) L10. The exhaust gas circulation path L10 connects between the exhaust path L6 and the exhaust path L4. The exhaust gas circulation path L10 circulates and supplies the exhaust gas via the classifier 43 to the exhaust path L4. A flow rate adjustment valve 55 is provided in the exhaust gas circulation path L10. The flow rate adjustment valve 55 can adjust the flow rate of the exhaust gas flowing through the exhaust gas circulation path L10. It is also possible to prevent the exhaust gas from flowing through the exhaust gas circulation path L10 by closing the flow rate adjustment valve 55. With this configuration, the flow rate of the exhaust gas supplied to the desulfurization reactors 41 and 42 can be adjusted, so that the state of the circulating fluidized bed S can be adjusted to a suitable state. That is, even when the exhaust gas flow rate is small, more gas than the exhaust gas flow rate can be supplied to the desulfurization reactors 41 and 42. Thereby, the load range (exhaust gas flow rate range) of the marine engine capable of generating the circulating fluidized bed S can be increased.

  Moreover, in the said embodiment, although the case where the circulating fluidized bed was formed with the fluidized material P1 was described as an example, the present invention is not limited to this. For example, when another fluidized bed such as a bubble fluidized bed is formed. Even if it exists, application of this invention is possible.

  Moreover, in the said embodiment, although it was set as the structure which provides the bug filter 44, it is not limited to this, For example, it may replace with the bug filter 44 and the structure which provided the filter of the simple structure may be sufficient.

  Moreover, in the said embodiment, although the aspect in which two types of granular materials, the fluidizing material P1 and the desulfurization agent P2, were used as the granular material P was described as an example, the embodiment is not limited to this. An embodiment in which only the desulfurizing agent P2 is used without using the material P1 may be used. Moreover, in the said embodiment, although the dry type was used, a wet and semi-dry type may be used.

  In the above embodiment, the desulfurization systems 40, 40A and 40B have been described by taking as an example the configuration in which the two desulfurization reactors 41 and 42 are provided, but the present invention is not limited to this. Three or more desulfurization reactors may be provided. In this case, the exhaust path L4 is branched according to the number of desulfurization reactors. Further, each branch path from the exhaust path L4 may be provided with a valve whose opening degree can be individually adjusted, and the opening degree of each valve may be controlled by the valve control unit VC.

α1, β1, γ1, α2, β2, γ2 Threshold value K Internal K1 Chamber K2 Flow section L1, L3 Intake path L2, L4, L41, L5, L42, L6, L7, L8 Exhaust path L9 Exhaust gas recirculation path L10 Exhaust gas circulation path P granular material P1 fluidized material P2 desulfurizing agent R fluidized material circulation part S circulating fluidized bed V1, V2 volume VC valve control part 10 exhaust gas treatment device 11 diesel engine 12 cylinder part 13 scavenging trunk 14 exhaust manifold 21 cylinder 22 intake port 23 exhaust port 24 Injector 31 Exhaust turbine supercharger 32 Compressor 33 Turbine 34 Rotating shaft 35 Air cooler 40, 40A, 40B Desulfurization system 41, 42, 81, 82 Desulfurization reactor 41a First valve 42a Second valve 43 Classifier 44 Bag filter 45 Supply piping 45a, 45b Downcomer 46 Desulfurization agent supply unit 46a Supply amount adjustment unit 47 Desulfurization agent recovery unit 48 Denitration device 49 Chimney 50, 55 Flow control valve 51 Housing 52, 61, 71 Exhaust gas inlet 53 Dispersion plates 54, 62, 73 Exhaust gas outlet 63 Fluid recovery Part 72 filter part 74 separation part 75 piping 76 tank part

Claims (10)

A desulfurization system for removing sulfur oxides from exhaust gas discharged from a marine engine,
A plurality of reactors through which the exhaust gas flows and reacts sulfur oxides with a desulfurizing agent;
A desulfurization agent supply unit for supplying a desulfurization agent to the reactor;
A flow rate adjusting unit capable of individually adjusting the flow rate of the exhaust gas introduced into the plurality of reactors;
A desulfurization system comprising: an adjustment amount control unit that controls the flow rate adjusting unit according to a flow rate of the exhaust gas discharged from the marine engine and changes the number of the reactors that supply the exhaust gas.   The desulfurization system according to claim 1, wherein the adjustment amount control unit increases the number of the reactors that supply the exhaust gas as the flow rate of the exhaust gas discharged from the marine engine increases. The reactor is a dry desulfurization reactor in which a fluid material that is solid particles and can flow when the exhaust gas has a predetermined flow rate is stored,
The desulfurization system according to claim 1 or 2, wherein the desulfurization agent is in the form of solid particles. When the flow rate of the exhaust gas discharged from the marine engine is increased and the number of the reactors supplying the exhaust gas is increased, the adjustment amount control unit,
The amount of exhaust gas supplied to the reactor for newly supplying exhaust gas is increased while maintaining a flow rate of exhaust gas supplied to the reactor supplying the exhaust gas at a flow rate at which a fluidized bed is formed. Desulfurization system described in. When the flow rate of the exhaust gas discharged from the marine engine is increased and the number of the reactors supplying the exhaust gas is increased, the adjustment amount control unit,
The amount of exhaust gas supplied to the reactor for newly supplying exhaust gas is increased while the flow rate of exhaust gas supplied to the reactor supplying the exhaust gas is decreased within the range of the flow rate at which a fluidized bed is formed. Item 4. The desulfurization system according to Item 3.   Arranged downstream of the reactor in the flow direction of the exhaust gas, separating the fluidizing material and the desulfurizing agent, supplying the fluidizing material to the reactor, and bringing the desulfurizing agent and the exhaust gas downstream. A desulfurization system according to any one of claims 3 to 5, comprising a classifier for discharging.   The desulfurization system according to claim 6, further comprising a filter that is disposed downstream of the classifier in the flow direction of the exhaust gas and collects the desulfurization agent contained in the exhaust gas via the classifier.   The relationship between the average particle size of the fluidized material and the average particle size of the desulfurizing agent satisfies 15 ≦ (average particle size of the fluidized material / average particle size of the desulfurized agent) ≦ 33. The desulfurization system according to any one of the above.   The desulfurization system according to any one of claims 1 to 8, wherein the plurality of reactors have the same volume and internal shape.   A desulfurization system according to any one of claims 1 to 9, and a nitrogen oxide from the exhaust gas, which is provided downstream of the dry desulfurization reactor constituting the dry desulfurization system in the flow direction of the exhaust gas. An exhaust gas treatment device comprising a denitration device for removing water.

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