JP4637658B2 - CWP collection system and CWP collection method - Google Patents

Description

  The present invention relates to a CWP recovery system for recovering CWP discharged from a pressurized fluidized bed boiler power generation device when the boiler of the pressurized fluidized bed boiler power generation device using coal, limestone, and water containing CWP adjusted as fuel is stopped. And a CWP recovery method.

  The pressurized fluidized bed boiler power generator employs a combined power generation system that generates steam by driving the steam turbine using the combustion heat generated by burning coal and driving the gas turbine with the combustion gas. Since the pressurized fluidized bed boiler fluidizes the fluid medium in the boiler and combusts the supplied coal while fluidizing it, the combustion temperature is as low as about 860 ° C. As a result, generation of nitrogen oxides is suppressed. Furthermore, the use of limestone as the fluid medium has the advantage that desulfurization in the furnace can be performed simultaneously.

  FIG. 5 is a diagram showing a part of a schematic configuration of a pressurized fluidized bed boiler power generation apparatus 1 conventionally used. The pressurized fluidized bed boiler 2 is installed in the pressure vessel 3, and the inside of the furnace is maintained at a pressure of about 1 MPa. The pressurized fluidized bed boiler 2 has a fluidized medium 4 in the furnace and is fluidized with air supplied from the furnace bottom 5. Coal as fuel is supplied into the fluid medium 4 at the lower part of the furnace through the fuel supply line 6 in a state where coal, limestone, and water are mixed. The pressurized fluidized bed boiler 2 has a BM (bed material) tank 7 for storing a fluidized medium in order to adjust the bed height of the fluidized bed.

  The pressurized fluidized bed boiler 2 has a water pipe 8 and a brackish water separator 9, generates steam by combustion heat obtained by burning coal, and drives a steam turbine and a generator (not shown) to generate electricity. The combustion gas is sent to a gas turbine (not shown) through a dust removing device (not shown), and a generator is driven to generate power.

  The fuel supplied to the pressurized fluidized bed boiler 2 is adjusted in the following manner. The coal stored in the raw coal bunker 10 is pulverized by the coarse pulverizer 11, classified into coal having a predetermined particle size by the classifier 12, and sent to the fine pulverizer 14 via the relay hopper 13. The coarsely pulverized coal sent to the pulverizer 14 is added with water and wet pulverized. On the other hand, limestone is sent to the kneader 16 via the limestone hopper 15 and kneaded with pulverized coal sent from the pulverizer 14 and water. The adjusted fuel is supplied to the furnace by the fuel pump 18 via the fuel tank 17.

  The fuel is also called CWP (Coal Water Paste) because it is a paste-like mixture of coal, limestone and water. Since CWP is a paste-like substance, it is not easy to handle. For this reason, in a pressurized fluidized bed boiler power generator, (1) CWP is stably supplied regarding CWP. (2) A method of recovering CWP discharged from a pressurized fluidized bed boiler power generator when the boiler is stopped. These are technical issues.

  The following techniques are disclosed as techniques for stably and continuously supplying CWP. In order to improve the thermal efficiency of the pressurized fluidized bed boiler, it is necessary to reduce the moisture contained in the CWP as much as possible. On the other hand, a decrease in the amount of water leads to an increase in the viscosity of the CWP fuel, making it difficult to transport. For this reason, a method of optimizing the particle size distribution of coal is used as a method of minimizing the water content while maintaining the fluidity of the CWP fuel.

Further, as a method for stably supplying CWP fuel, a method is disclosed in which the particle size distribution of coal and limestone is prevented from being biased during storage of CWP fuel in a CWP storage tank (see Patent Document 1). In this method, instead of a conventional vertical stirrer, a horizontal stirrer is attached to a CWP storage tank, and the CWP being stored is stirred and mixed. In addition to this, a technique for efficiently managing the viscosity of CWP in order to stably supply CWP is also disclosed (see, for example, Patent Document 2).
Japanese Patent Application Laid-Open No. 11-237035 JP 2000-266336 A

  The technical problem of the method of recovering CWP discharged from the pressurized fluidized bed boiler power generator when the boiler is stopped is as follows. CWP discharged and recovered from the pressurized fluidized bed boiler power generation facility when the boiler is stopped is used as a part of the fuel when the boiler is started up and mixed with the newly adjusted fuel, but when CWP is recovered when the boiler is stopped Alternatively, when the recovered CWP is reused, the CWP is blocked in the pipe being transported.

  One of the causes of CWP clogging in the piping is the shape (length, caliber, bent part, etc.) of the pipeline that collects or transports CWP. Therefore, there is a limit in providing an appropriate piping shape and piping route. In particular, in a CWP recovery system that has already been installed, it is not easy to change the piping shape or the transportation route significantly. Therefore, an inexpensive CWP recovery system and recovery method in which the CWP recovered when the boiler stops is not blocked in the pipe, and when the recovered CWP is reused, the CWP is not blocked in the pipe being transported. The development of such is waiting.

  An object of the present invention is a CWP recovery system that is inexpensive and can stably transport CWP without clogging the CWP in the pipe when recovering CWP or transporting the recovered CWP again. And providing a CWP recovery method.

The present invention relates to CWP recovery for recovering CWP discharged from a pressurized fluidized bed boiler power generation device when the boiler of the pressurized fluidized bed boiler power generation device using coal, limestone, and water containing CWP prepared as fuel is stopped. A system,
A crusher that accepts CWP discharged from the pressurized fluidized bed boiler power generator when the boiler is stopped, and crushes solids contained in the CWP;
And a CWP recovery tank for storing CWP whose solid content has been pulverized by the pulverizer.

Further, in the present invention, the pressurized fluidized bed boiler power generator comprises a pulverizer for pulverizing coal,
2. The CWP recovery system according to claim 1, wherein the pulverizer that pulverizes the solid content contained in the CWP is the pulverizer that finely pulverizes the coal.

Further, in the present invention, the CWP recovery system according to claim 1 or 2 is recovered in the CWP recovery pit for receiving CWP discharged from the pressurized fluidized bed boiler power generation device when the boiler is stopped, and the CWP recovery pit. A CWP recovery pump for supplying the CWP to the pulverizer,
The crusher is provided in the vicinity of the CWP recovery pump, and is a CWP recovery system.

The present invention also provides CWP recovery for recovering CWP discharged from a pressurized fluidized bed boiler power generation device when the boiler of the pressurized fluidized bed boiler power generation device using coal, limestone, and water as a fuel and adjusted CWP is used as fuel. A method,
A CWP recovery method characterized in that CWP discharged from a pressurized fluidized bed boiler power generator is pulverized by a pulverizer and then stored when the boiler is stopped.

  According to the present invention, a pulverizer that pulverizes solids contained in CWP that includes coal, limestone, and water discharged when the pressurized fluidized bed boiler is stopped, and CWP pulverized by the pulverizer are stored. Since the CWP recovery tank is included, the CWP can be stored in the CWP recovery tank after pulverizing the solids contained in the CWP with a pulverizer. Since the CWP is pulverized in advance before storing the CWP, the particle size of the solid content contained in the CWP is reduced, and the CWP is not blocked in the piping when the CWP is transported to the CWP recovery tank. Even if the CWP stored in the CWP recovery tank is transported again, the particle size of the solids contained in the CWP is reduced, so that the CWP is not blocked in the pipe during transportation.

  Further, according to the present invention, the pressurized fluidized bed boiler power generation apparatus includes a pulverizer for finely pulverizing coal, and the pulverizer for pulverizing CWP discharged when the boiler is stopped is a pulverizer for pulverizing coal. There is no need for a pulverizer for pulverizing the solid content contained in CWP. Further, the CWP pulverization when collecting the CWP is performed when the boiler is stopped, so that it does not overlap with the coal pulverization operation. Therefore, it does not hinder the coal pulverization operation.

  The CWP recovery system of the present invention includes a CWP recovery pit that receives CWP discharged from the pressurized fluidized bed boiler power generation device when the boiler is stopped, and a CWP recovery pump that supplies the CWP recovered in the CWP recovery pit to the pulverizer. Since the pulverizer is provided close to the CWP recovery pump, the recovered CWP is sent to the pulverizer through a short path. For this reason, even if the CWP is pulverized by a pulverizer and before the particle size is reduced, the CWP is not blocked in the pipe.

  The recovered CWP is used by being mixed with CWP, which is a newly adjusted fuel. Since the recovered CWP is pulverized by a pulverizer, the particle size of the collected CWP with respect to the newly adjusted fuel is small although the particle size of the solid content is smaller than that of the newly adjusted CWP. The impact on the process can be ignored.

  FIG. 1 is a diagram showing a schematic configuration of a CWP recovery system 30 when a pressurized fluidized bed boiler is stopped as one embodiment of the present invention. When the pressurized fluidized bed boiler is stopped, it becomes unnecessary to supply CWP as fuel to the pressurized fluidized bed boiler. At the same time, it is necessary to extract CWP from a CWP adjusting device for adjusting CWP, a CWP supplying device for supplying CWP to a pressurized fluidized bed boiler, etc., which constitutes a part of a pressurized fluidized bed boiler power generation facility in preparation for restart. The resulting and extracted CWP is stored in a storage tank for reuse.

  The kneading machine 31 constituting the CWP adjusting device adjusts CWP as fuel by stirring and mixing coal, limestone, and water. When the pressurized fluidized bed boiler is stopped, the CWP in the kneading machine is recovered by CWP. It is discharged into the pit 32. Similarly, CWP in the CWP pump 33 constituting the CWP supply device is also discharged to the CWP recovery pit 32. The CWP recovery pit 32 includes a CWP recovery pump 34 that can transport the recovered CWP, and a pipe 35 is disposed at a discharge portion of the CWP recovery pump 34. One end of the pipe line 35 is connected to the three-way valve 36, and one side of the three-way valve 36 is connected to the pipe line 38 connected to the CWP recovery tank 37, and the other side is connected to the pipe line 40 connected to the pulverizer 39. .

  The fine pulverizer 39 forms pulverized coal constituting CWP as fuel for the pressurized fluidized bed boiler. The fine pulverizer 39 receives coal from the coal feeder 41 through the pipeline 42 and pulverizes the received coal into a predetermined size. To do. Further, as will be described later, the recovered CWP is pulverized. The fine pulverizer 39 includes a conduit 44 that can transport the pulverized pulverized material to the slurry relay tank 43. The slurry relay tank 43 temporarily stores the crushed material (slurry) that has been sent. The slurry relay tank 43 includes slurry discharge conduits 45 and 46, and the first slurry discharge conduit 45 is connected to the slurry transfer pump 47. On the other hand, the second slurry discharge conduit 46 guides the slurry in the slurry relay tank 43 to the slurry recovery pit 48.

  The slurry transfer pump 47 includes a pipe line 49 in the discharge portion, and the pipe line 49 is connected to the slurry service tank 50 at one end. The slurry service tank 50 has a slurry discharge pipe 51, and one end of the slurry discharge pipe 51 is connected to the slurry supply pump 52. The slurry supply pump 52 is a pump that transports the slurry stored in the slurry services tank 50 to the kneading machine 31, and has a pipe line 53 that connects one end to the kneading machine 31 at the discharge part. The slurry sent to the kneading machine 31 is newly adjusted as CWP by the kneading machine 31.

  The slurry collection pit 48 includes a slurry collection pump 54 that can transport the collected CWP (slurry). The slurry collection pump 54 sucks the slurry through the suction line 55 and sends the slurry to the CWP collection tank 37 through the discharge line 56 of the slurry collection pump 54. The CWP recovery tank 37 has a CWP supply pump 57 for transferring the stored CWP (slurry). The CWP supply pump 57 has a pipe line 58 connected to the CWP recovery tank 37 and a discharge pipe line 59 for transporting the recovered CWP to the pulverizer 39.

  Next, a method for collecting CWP discharged from a CWP adjustment device, a CWP supply device, or the like will be described. FIG. 2 is a diagram for explaining the CWP recovery method of the present invention, and shows a path for recovering CWP to the CWP recovery tank 37 using the CWP recovery system 30 shown in FIG. FIG. 3 is a comparative example of the present invention, and is a diagram showing a path for collecting CWP to the CWP recovery tank using the CWP recovery system 30 shown in FIG. FIG. 4 is a diagram showing a path when the recovered CWP in the CWP recovery tank 37 is reused using the CWP recovery system 30 shown in FIG.

  CWP discharged from a CWP adjustment device, a CWP supply device, or the like is stored in the CWP recovery pit 32. The CWP stored in the CWP recovery pit 32 is sent by a CWP recovery pump 34 through a pipe 35 to a three-way valve 36 attached to one end of the pipe 35. At this time, the three-way valve 36 communicates with the pipeline 40 so that the sent CWP can be transported to the pulverizer 39. As a result, the CWP in the CWP recovery pit is sent to the fine pulverizer 39. The solid content contained in the CWP is pulverized from the CWP sent to the pulverizer 39 by the pulverizer 39.

  CWP sent to pulverizer 39 and recovered is a paste-like substance with a coal content of about 70% by weight, a limestone content of about 7% by weight, and a water content of about 23% by weight. The particle size of coal and limestone is about 1 to 2 mm. Coal and limestone, which are solid components contained in the CWP, are pulverized by a fine pulverizer 39 to reduce the particle size. In the embodiment of the present invention shown in FIG. 1 or FIG. 2, since the fine pulverizer 39 for finely pulverizing coal is used for pulverizing CWP, a separate fine pulverizer for pulverizing CWP is not required.

  In the present invention, CWP is recovered when the pressurized fluidized bed boiler is stopped. Therefore, even if a fine pulverizer for pulverizing coal is used to pulverize solids contained in CWP, There is no overlap with the grinding operation. Therefore, the operation of crushing coal is not disturbed. The pulverizer for pulverizing coal is a pulverizer capable of fine pulverization, and can pulverize the solid content contained in the CWP sufficiently small.

  The CWP whose solid content has been crushed by the pulverizer 39 is sent to the slurry relay tank 43 through the pipe 44. The CWP sent to the slurry relay tank 43 is further sent to the slurry collection pit 48 through the conduit 46. The CWP sent to the slurry collection pit 48 is finally sent to the CWP collection tank 37 by the slurry collection pump 54 and stored therein.

  Since the CWP is transported as described above, the mounting position of the three-way valve 36 is set in the vicinity of the CWP recovery pump 34, the length of the conduit 40 is made as short as possible, and the CWP recovered through the short path is sent to the pulverizer 39. It is desirable. This is because it is possible to avoid clogging of the CWP in the piping by shortening the path until the recovered CWP is sent to the grinder 39. Since the CWP that has passed through the pulverizer 39 has a smaller solid particle size, the CWP may be blocked in the piping while the CWP is transported even if the path from the pulverizer 39 to the CWP recovery tank 37 is long. There is no. As described above, the CWP recovery method of the present invention can be recovered without blocking the CWP in the pipe with an inexpensive and simple configuration.

  In the conventional CWP recovery method, there are many examples of transporting to the CWP recovery tank 37 along the route shown in FIG. Specifically, CWP discharged from a CWP adjusting device, a CWP supply device, etc. is collected in the CWP collection pit 32, and then collected by the CWP collection pump 34 through the line 35, the three-way valve 36, and the line 38. It was sent to the tank 37 and stored here. In this method, since the CWP is transported by a long route in a state where the particle size of the solid content contained in the CWP is not sufficiently small, the CWP is often blocked in the pipe line. By adopting this method, the CWP is not blocked in the piping during transportation.

  When the CWP recovered in the CWP recovery tank 37 is reused, the recovered CWP is sent to the kneader 31 through the path shown in FIG. 4 and mixed with the newly adjusted CWP, and used as new fuel. The CWP is transported from the CWP recovery tank 37 to the kneading machine 31 in the following manner. The CWP stored in the CWP recovery tank 37 is sent to the CWP supply pump 57 through the pipe 58. The CWP supply pump 57 sends the CWP to the pulverizer 39 through the pipe line 59. The CWP sent to the pulverizer 39 is sent again to the slurry service tank 50 through the slurry relay tank 43, the pipe 45, the slurry transfer pump 47, and the pipe 49 after the solid content contained in the CWP is crushed again. It is done. The CWP sent to the slurry service tank 50 is sent to the kneader 31 by the slurry supply pump 52.

  The pulverizer 39 used here is the pulverizer 39 used when recovering CWP, and is a pulverizer that finely pulverizes coal. When the CWP is reused, the CWP as the fuel is newly adjusted at the same time. When adjusting CWP as a new fuel, coal pulverization is performed, and therefore, pulverization of coal and solid content pulverization operation may overlap. On the other hand, it is also possible to shift the time of these crushing operations as necessary. Even if these pulverization operations overlap, the amount of recovered CWP to be reused is very small compared to the amount of CWP newly adjusted, and the influence on coal pulverization is very small.

  In addition, when the pulverization of coal and the pulverization of solids contained in CWP are performed simultaneously, the handling of moisture contained in CWP becomes a problem, but since the pulverization of coal is wet pulverized, There is no adverse effect on grinding. Further, since the recovered CWP is used after being pulverized twice by the pulverizer 39, there is a concern about the size of the particle size. However, the recovered CWP is not used alone but newly adjusted. CWP is mixed and used, and the mixing ratio is very small, so there is almost no influence on the process. In the present embodiment, when the CWP stored in the CWP recovery tank is reused, it is pulverized again by the pulverizer and used. However, the pulverizer may not be pulverized again.

  In the above embodiment, a pump is used for transporting CWP (slurry), and tanks and pits are used to store CWP. However, for example, a pulverizer 39 is disposed below the kneader 31. Thus, it goes without saying that the CWP recovery pit 32 and the CWP recovery pump 34 can be omitted.

  As described above, when the CWP discharged from the pressurized fluidized bed boiler power generation apparatus is collected, the present invention pulverizes and stores the CWP, so that the particle size of the solid content contained in the CWP is reduced and transported. CWP is not blocked in the pipe. Also, when the stored CWP is reused, the particle size of the solid content of the CWP is small, so that the CWP is not blocked in the pipe during transportation. The CWP can be recovered and transported with a very simple configuration without clogging the pipe in the pipe.

  Further, the CWP recovery system of the present invention is characterized in that when recovering CWP discharged from a pressurized fluidized bed boiler power generation apparatus to a CWP recovery tank, the recovered CWP is pulverized and recovered by a pulverizer. The conventional CWP recovery system can be easily applied by providing a pipe line for sending the recovered CWP to the pulverizer.

It is a figure showing a schematic structure of CWP collection system 30 as one embodiment of the present invention. It is a figure for demonstrating the CWP collection | recovery method of this invention, Comprising: It is a figure which shows the path | route which collect | recovers CWP to the CWP collection tank 37 using the CWP collection | recovery system 30 shown in FIG. FIG. 3 is a comparative example of the present invention, and is a diagram showing a path for collecting CWP to a CWP collection tank 37 using the CWP collection system 30 shown in FIG. 1. It is a figure for demonstrating the CWP collection | recovery method of this invention, Comprising: It is a figure which shows the path | route which conveys the collect | recovered CWP to the kneader 31 using the CWP collection | recovery system 30 shown in FIG. It is a figure which shows a part of schematic structure of the pressurization fluidized bed boiler electric power generation apparatus 1 conventionally used.

Explanation of symbols

30 CWP recovery system 31 Kneader 32 CWP recovery pit 33 CWP pump 34 CWP recovery pump 37 CWP recovery tank 39 Fine grinding machine

Claims (4)

A CWP recovery system that recovers CWP discharged from a pressurized fluidized bed boiler power generation device when the boiler of the pressurized fluidized bed boiler power generation device using coal, limestone, and water that is adjusted and containing CWP as a fuel is stopped. ,
A crusher that accepts CWP discharged from the pressurized fluidized bed boiler power generator when the boiler is stopped, and crushes solids contained in the CWP;
And a CWP recovery tank for storing CWP whose solid content has been pulverized by the pulverizer. The pressurized fluidized bed boiler power generator comprises a pulverizer for pulverizing coal,
The CWP recovery system according to claim 1, wherein the pulverizer that pulverizes the solid content contained in the CWP is the pulverizer that finely pulverizes coal. The CWP recovery system according to claim 1 or 2, wherein the CWP recovery pit that receives CWP discharged from the pressurized fluidized bed boiler power generator when the boiler is stopped, and the CWP recovered in the CWP recovery pit is pulverized. Equipped with a CWP recovery pump to supply the machine,
The CWP recovery system, wherein the pulverizer is provided close to the CWP recovery pump. A CWP recovery method for recovering CWP discharged from a pressurized fluidized bed boiler power generation device when the boiler of the pressurized fluidized bed boiler power generation device using coal, limestone, and water containing CWP adjusted as fuel is stopped,
A CWP recovery method, wherein CWP discharged from a pressurized fluidized bed boiler power generator is pulverized by a pulverizer and then stored when the boiler is stopped.

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