JP2001336736A - Method and device for controlling concentration of exhaust gas oxygen of oxygen combustion boiler equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for controlling concentration of exhaust gas oxygen of an oxygen combustion boiler capable of preventing the occurrence of instability of exhaust gas concentration, stabilizing combustion of fuel in a boiler body, and effecting smooth operation. SOLUTION: A control command 48 to regulate a flow rate of the atmosphere so that outlet oxygen concentration 45 of the boiler body 1 is equalized to an outlet oxygen concentration set value 47 is outputted to a fan 31 during starting. When starting is completed, a control command 49 to regulate a flow rate of oxygen fed from a high purity oxygen manufacturing device so that the outlet oxygen concentration 45 is rendered equal to the outlet oxygen concentration set value 47 is outputted to an oxygen introduction damper 42. Further, a controller 51 is provided such that the control command 48 to regulate a flow rate of exhaust gas circulation flow rate of exhaust gas so that inlet oxygen concentration 43 of the boiler body 1 is equalized to an inlet oxygen amount concentration set value 50 is outputted to the fan 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling the concentration of exhaust gas oxygen in an oxyfuel boiler facility.

[0002]

2. Description of the Related Art FIG. 2 shows an example of a boiler provided in a power plant or the like. In FIG.
Is a burner that injects fuel into the boiler body 1 and burns it,
3 is a primary superheater, 4 is a secondary superheater, 5 is a tertiary superheater, 6
Is a final superheater, 7 is a primary reheater, 8 is a secondary reheater, 9 is a economizer, and generates fuel gas by injecting fuel from the burner 2 into the boiler body 1 and burning it. Then, the generated combustion gas is circulated, and the secondary superheater 4, the tertiary superheater 5, the final superheater 6, the secondary reheater 8, the primary superheater 3, the primary reheater 7, and the economizer 9 are provided. After the heat exchange, the exhaust gas after the heat exchange was discharged to the exhaust gas duct 10, and nitrogen oxides, sulfur oxides, and the like were removed by a flue gas treatment device (not shown) such as denitration and desulfurization provided on the downstream side. Later, they are released to the atmosphere.

On the other hand, FIG. 3 shows a water supply / steam system of the above-mentioned boiler. Boiler water is heated by an evaporator 11 formed on a furnace wall of a boiler main body 1 in which fuel is burned, and a nose is formed. Through the section 12, the steam and water are separated by the steam separator 13, and the steam separated from the water by the steam separator 13 passes through the ceiling of the boiler main body 1 and the peripheral wall 14 of the rear heat transfer section, and the primary superheater 3, superheated by the secondary superheater 4, the tertiary superheater 5, and the final superheater 6, guided to the high-pressure turbine 15,
The high-pressure turbine 15 is driven to generate electric power, and the steam after driving the high-pressure turbine 15 is guided to the primary reheater 7 and the secondary reheater 8, where the primary reheaters 7 and After being reheated by the secondary reheater 8, the medium / low pressure turbine 16
And the steam after driving the medium / low pressure turbine 16 is guided to the condenser 17 and returned to the boiler feedwater, where the steam is supplied to the boiler feedwater. Is conveyed to the economizer 9 via a condensate desalination unit 18, a low-pressure feedwater heater 19 and a deaerator 20, and a high-pressure feedwater heater 22 by a feedwater pump 21. It is heated, sent to the evaporator 11, and circulated.

In recent years, it has been desired to reduce greenhouse gas emissions such as carbon dioxide in order to prevent global warming. Development of technology for waste disposal in the ocean or underground is underway.

FIG. 4 shows an example of an oxyfuel boiler system proposed to recover carbon dioxide in exhaust gas and dispose of it in the ocean or underground. , An air supply line 31, a fan provided in the middle of the air supply line 30, an exhaust gas line 32 connected to the outlet side of the boiler body 1, a chimney 33, and an exhaust gas circulation line from the middle of the exhaust gas line 32. 34
And is connected to the upstream side of the fan 31 of the air supply line 30, and an exhaust gas damper 35 is provided in the exhaust gas line 32 on the downstream side of the branch portion of the exhaust gas circulation line 34. An air supply damper 36 is provided in the middle of the air supply line 30 on the upstream side, an exhaust gas circulation damper 37 is provided in the middle of the exhaust gas circulation line 34, and the carbon dioxide recovery damper 3 is provided in the middle.
The carbon dioxide recovery line 39 provided with 8 is branched from a required portion of the exhaust gas circulation line 34, and oxygen supplied from the high-purity oxygen production device 40 is introduced into the air supply line 30 downstream from the fan 31. And an oxygen introduction damper 42 is provided in the middle of the oxygen introduction line 41.

In the oxyfuel boiler system shown in FIG. 4, since oxygen cannot be supplied from the high-purity oxygen production apparatus 40 at the time of startup, the oxygen introduction damper 42, the exhaust gas circulation damper 37, and the carbon dioxide recovery damper 38 With the air supply damper 36 and the exhaust gas damper 35 open, the air is introduced into the boiler main body 1 through the air supply line 30 by the operation of the fan 31 and the air is burned in the same manner as in a normal boiler. The exhaust gas discharged from the boiler body 1 is discharged from a chimney 33 to the atmosphere via an exhaust gas line 32, and after the start-up is completed, the exhaust gas circulation damper 3
7, the air supply damper 36 and the exhaust gas damper 35 are closed, the exhaust gas discharged from the boiler main body 1 is circulated by the exhaust gas circulation line 34 so as not to be discharged from the chimney 33, and the opening degree of the oxygen introduction damper 42 is reduced. Adjust,
Oxygen supplied from the high-purity oxygen production apparatus 40 is introduced into the boiler main body 1 through the oxygen introduction line 41, and oxyfuel combustion of fuel is performed while suppressing a decrease in oxygen concentration due to circulation of exhaust gas. The carbon dioxide concentration is increased, the carbon dioxide recovery damper 38 is opened appropriately, a part of the exhaust gas having the increased carbon dioxide concentration is extracted from the carbon dioxide recovery line 39, and compressed and recovered by a compressor (not shown). They are disposed of in the ocean or underground.

[0007]

However, in the oxyfuel boiler facility as described above, since a specific control method has not been established, the exhaust gas oxygen concentration becomes unstable,
There is a possibility that the combustion of the fuel in the boiler body 1 becomes unstable and the operation cannot be continued.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to prevent the exhaust gas oxygen concentration from becoming unstable, to stabilize the combustion of fuel in the boiler body, and to smoothly perform the operation. It is an object of the present invention to provide an exhaust gas oxygen concentration control method and apparatus.

[0009]

According to the present invention, at the time of startup,
Atmosphere is introduced into the boiler body to burn fuel, and after the start-up is completed, the exhaust gas is circulated while introducing oxygen supplied from the high-purity oxygen generator into the boiler body to perform oxyfuel combustion of the fuel. An exhaust gas oxygen concentration control method for an oxyfuel boiler facility that compresses and recovers a part of an exhaust gas having an increased carbon concentration, wherein at startup, the outlet oxygen concentration of the boiler body is equal to the outlet oxygen concentration set value. After the start-up is completed, the flow rate of oxygen supplied from the high-purity oxygen production apparatus is adjusted so that the outlet oxygen concentration of the boiler body becomes equal to the outlet oxygen concentration set value, and the inlet of the boiler body is adjusted. The present invention relates to an exhaust gas oxygen concentration control method for an oxyfuel boiler facility, which comprises adjusting an exhaust gas circulation flow rate so that an oxygen concentration becomes equal to an inlet oxygen concentration set value.

Also, according to the present invention, at the time of startup, the air is introduced into the boiler main body by operating the fan to burn the fuel into the atmosphere, and after the startup is completed, oxygen supplied from the high-purity oxygen producing apparatus is supplied to the boiler main body. Oxygen combustion boiler equipment that circulates exhaust gas by operating a fan while introducing it by adjusting the opening of the oxygen introduction damper, performs oxyfuel combustion of the fuel, and compresses and recovers part of the exhaust gas with an increased carbon dioxide concentration. An exhaust gas oxygen concentration control device, comprising: an inlet oximeter for detecting an inlet oxygen concentration of a boiler main body; an outlet oximeter for detecting an outlet oxygen concentration of a boiler main body; Outputs a control command to the fan to adjust the air flow rate so that the outlet oxygen concentration of the boiler main unit becomes equal to the outlet oxygen concentration set value. A control command for adjusting the flow rate of oxygen supplied from the high-purity oxygen production apparatus is output to the oxygen introduction damper so that the detected outlet oxygen concentration of the boiler body becomes equal to the outlet oxygen concentration set value, and the inlet oxygen concentration A controller for outputting to the fan a control command for adjusting the exhaust gas circulation flow rate so that the inlet oxygen concentration of the boiler body detected by the meter becomes equal to the inlet oxygen concentration set value. It relates to the exhaust gas oxygen concentration control device of the facility.

According to the above means, the following effects can be obtained.

In the method for controlling the exhaust gas oxygen concentration of the oxyfuel combustion boiler equipment of the present invention, the flow rate of the atmosphere introduced into the boiler main body is adjusted at the time of start-up so that the outlet oxygen concentration of the boiler main body becomes equal to the outlet oxygen concentration set value. Atmosphere combustion of the fuel is performed, and after the start-up is completed, the flow rate of oxygen supplied from the high-purity oxygen production apparatus is adjusted so that the outlet oxygen concentration of the boiler body becomes equal to the outlet oxygen concentration set value, and the boiler body The exhaust gas circulating flow rate is adjusted so that the inlet oxygen concentration becomes equal to the inlet oxygen concentration set value, whereby the reduction of the oxygen concentration due to the circulation of the exhaust gas is reliably suppressed, and the oxyfuel combustion of the fuel is performed stably, The concentration of carbon dioxide in the exhaust gas is increased, and part of the exhaust gas with the increased carbon dioxide concentration is compressed and collected, and is disposed of in the ocean or underground.

Further, in the exhaust gas oxygen concentration control apparatus for an oxyfuel boiler facility according to the present invention, at the time of startup, the atmospheric oxygen concentration is set so that the outlet oxygen concentration of the boiler main body detected by the outlet oxygen concentration meter becomes equal to the outlet oxygen concentration set value. A control command for adjusting the flow rate is output from the controller to the fan, the flow rate of the air introduced into the boiler body is adjusted by the operation of the fan, the fuel is burned to the atmosphere, and after the startup is completed, the outlet oxygen concentration is determined. A control command for adjusting the flow rate of oxygen supplied from the high-purity oxygen production apparatus is output from the controller to the oxygen introduction damper so that the outlet oxygen concentration of the boiler body detected by the meter becomes equal to the outlet oxygen concentration set value. The flow rate of the oxygen supplied from the high-purity oxygen production apparatus is adjusted so that the opening degree of the oxygen introduction damper is adjusted and the outlet oxygen concentration of the boiler body is equal to the outlet oxygen concentration set value. Is controlled, and a control command for adjusting the exhaust gas circulating flow rate is output from the controller to the fan so that the inlet oxygen concentration of the boiler body detected by the inlet oximeter becomes equal to the inlet oxygen concentration set value. , The exhaust gas circulation flow rate is adjusted so that the inlet oxygen concentration of the boiler main unit becomes equal to the inlet oxygen concentration set value, whereby the reduction of the oxygen concentration due to the circulation of the exhaust gas is suppressed and the oxygen combustion of the fuel is stabilized. The carbon dioxide concentration in the exhaust gas is increased, and part of the exhaust gas with the increased carbon dioxide concentration is compressed and collected,
Disposed in the ocean and underground.

As a result, in the method and apparatus for controlling the exhaust gas oxygen concentration of the oxyfuel boiler equipment of the present invention, the exhaust gas oxygen concentration does not become unstable, the fuel combustion in the boiler body is stabilized, and the smooth operation is continued. It becomes possible.

[0015]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an example of an embodiment of the present invention. In the figure, the portions denoted by the same reference numerals as those in FIG. 4 represent the same components, and the basic configuration is the same as that shown in FIG. The features of the illustrated example are the same, but as shown in FIG. 1, the inlet oxygen concentration meter 44 for detecting the inlet oxygen concentration 43 of the boiler main body 1 and the outlet oxygen concentration 45 of the boiler main body 1 are detected. An outlet oxygen concentration meter 46 and an outlet oxygen concentration 45 of the boiler main body 1 detected by the outlet oxygen concentration meter 46 at the time of startup.
Outputs a control command 48 to the fan 31 for adjusting the flow rate of the atmosphere so that the outlet oxygen concentration set value 47 becomes equal to the outlet oxygen concentration set value 47,
After the start-up is completed, the outlet oxygen concentration 45 of the boiler main body 1 detected by the outlet oxygen concentration meter 46 becomes the outlet oxygen concentration set value 47.
A control command 49 for adjusting the flow rate of oxygen supplied from the high-purity oxygen production apparatus 40 is output to the oxygen introduction damper 42 so as to be equal to, and the inlet oxygen of the boiler main body 1 detected by the inlet oxygen concentration meter 44 The point is that a controller 51 for outputting a control command 48 for adjusting the exhaust gas circulation flow rate to the fan 31 so that the concentration 43 becomes equal to the inlet oxygen concentration set value 50 is provided.

In the case of the illustrated example, the controller 51 comprises an outlet oxygen concentration set value 47 of the boiler body 1 and an outlet oxygen concentration meter 4.
6, a subtractor 53 for obtaining a difference from the outlet oxygen concentration 45 of the boiler main body 1 detected at 6 and outputting an outlet oxygen concentration deviation 52;
Proportional-integral control which outputs an atmospheric flow rate control command 54 for adjusting the blade opening of the fan 31 for eliminating the outlet oxygen concentration deviation 52 by performing a proportional integration process on the outlet oxygen concentration deviation 52 output from the subtracter 53. A subtractor 57 for calculating a difference between the inlet oxygen concentration 43 of the boiler main body 1 detected by the inlet oximeter 44 and the inlet oxygen concentration set value 50 of the boiler main body 1 and outputting an inlet oxygen concentration deviation 56; Proportional integration processing of the inlet oxygen concentration deviation 56 output from the subtractor 57 to output an exhaust gas circulating flow rate control command 58 for adjusting the blade opening of the fan 31 for eliminating the inlet oxygen concentration deviation 56 At the time of startup, the controller 59 outputs the atmospheric flow rate control command 54 output from the proportional-integral controller 55 to the fan 31 as a control command 48 to the fan 31 at the time of startup, and after the startup is completed. Exhaust gas circulation flow rate control command is switched in FIG side b is outputted from the proportional integral adjuster 59 5
6 that outputs 8 as control command 48 to fan 31
0 and a proportional-integral adjuster 62 for outputting an opening control command 61 of the oxygen introduction damper 42 for eliminating the outlet oxygen concentration deviation 52 by performing a proportional integral process on the outlet oxygen concentration deviation 52 output from the subtractor 53. At the time of startup, the switch is switched to the side a in the figure and the fully closed command 63 is output to the oxygen introduction damper 42 as the control command 49, and after the start is completed, the switch is switched to the side b in the figure and output from the proportional integral controller 62. The opening control command 61 is used as the control command 49 as the oxygen introduction damper 42.
And a switch 64 that outputs the data to

Next, the operation of the illustrated example will be described.

At the time of startup, the switch 60 is switched to the side a in the figure, and the switch 64 is also switched to the side a in the figure, and the fully closed command 63 is output to the oxygen introduction damper 42 as the control command 49, and the oxygen The introduction damper 42 is closed, and
When the exhaust gas circulation damper 37 and the carbon dioxide recovery damper 38 are closed and the air supply damper 36 and the exhaust gas damper 35 are open, the air is supplied to the boiler through the air supply line 30 by the operation of the fan 31 in the same manner as a normal boiler. The exhaust gas discharged from the boiler main body 1 is introduced into the atmosphere through the exhaust gas line 32, and the exhaust gas discharged from the boiler main body 1 is released into the atmosphere through the exhaust gas line 32.
6, the outlet oxygen concentration 45 of the boiler main body 1 is detected and input to the subtractor 53 of the controller 51. In the subtractor 53 of the controller 51, the outlet oxygen concentration set value 47 of the boiler main body 1 and the outlet The difference from the outlet oxygen concentration 45 of the boiler main body 1 detected by the oximeter 46 is obtained, and the outlet oxygen concentration deviation 52 is output to the proportional-integral controller 55. The output outlet oxygen concentration deviation 52 is proportionally integrated, and an air flow rate control command 54 for adjusting the blade opening degree of the fan 31 for eliminating the outlet oxygen concentration deviation 52 is provided as a control command 48 via a switch 60 as a fan. 31 and the fan 31
The blade opening of the boiler is adjusted, and the outlet oxygen concentration
The flow rate of the atmosphere is adjusted so that 5 becomes equal to the outlet oxygen concentration set value 47. Since the oxygen concentration in the atmosphere is constant, it is not necessary to control the oxygen concentration 43 at the inlet of the boiler body 1 at the time of start-up in which the fuel is burned in the atmosphere.

After the start-up is completed, both the switch 60 and the switch 64 are switched to the side b in the figure, the exhaust gas circulation damper 37 is opened, the atmosphere supply damper 36 and the exhaust gas damper 35 are closed, and the boiler main body is closed. The exhaust gas discharged from the exhaust gas circulation line 1 is circulated by the exhaust gas circulation line 34 so as not to be discharged from the chimney 33. At this time, the outlet oxygen concentration 45 of the boiler main body 1 detected by the outlet oximeter 46 is determined by the controller 51 is input to a subtractor 53 of the controller 51.
In the subtractor 53, the difference between the outlet oxygen concentration set value 47 of the boiler main body 1 and the outlet oxygen concentration 45 of the boiler main body 1 detected by the outlet oximeter 46 is obtained, and the outlet oxygen concentration deviation 52 is proportionally adjusted. The output of the oxygen introduction damper 42 for eliminating the outlet oxygen concentration deviation 52 by performing a proportional integration process on the outlet oxygen concentration deviation 52 output from the subtractor 53 in the proportional integration controller 62. The control command 61 is output to the oxygen introduction damper 42 as a control command 49 via the switch 64, the opening degree of the oxygen introduction damper 42 is adjusted, and the outlet oxygen concentration 45 of the boiler main body 1 is equal to the outlet oxygen concentration set value 47. The flow rate of oxygen supplied from the high-purity oxygen producing apparatus 40 is adjusted so that the inlet oxygen concentration 43 of the boiler main body 1 is detected by the inlet oxygen concentration meter 44. , Input to the subtractor 57 of the controller 51, and the subtractor 57 of the controller 51 detects the inlet oxygen concentration 43 of the boiler body 1 and the set value of the inlet oxygen concentration of the boiler body 1 detected by the inlet oximeter 44. The difference from 50 is obtained, and the inlet oxygen concentration deviation 56 is output to the proportional-integral controller 59. In the proportional-integral controller 59, the inlet oxygen concentration deviation 56 output from the subtractor 57 is subjected to proportional integration processing. An exhaust gas circulating flow rate control command 58 for adjusting the blade opening of the fan 31 for eliminating the inlet oxygen concentration deviation 56 is output to the fan 31 as a control command 48 via the switch 60, and the blade opening of the fan 31 is The exhaust gas circulating flow rate is adjusted so that the inlet oxygen concentration 43 of the boiler main body 1 becomes equal to the inlet oxygen concentration set value 50, whereby the reduction of the oxygen concentration due to the exhaust gas circulation is ensured. Oxygen combustion of the fuel is performed in a stable manner, and the concentration of carbon dioxide in the exhaust gas is increased. By opening the carbon dioxide recovery damper 38 appropriately, a part of the exhaust gas with the increased carbon dioxide concentration Is extracted from the carbon dioxide recovery line 39, compressed and recovered by a compressor (not shown), and disposed of in the ocean or underground.

As a result, the oxygen concentration of the exhaust gas does not become unstable, the combustion of the fuel in the boiler main body 1 is stabilized, and the smooth operation can be continued.

In this way, the oxygen concentration of the exhaust gas can be prevented from becoming unstable, the combustion of fuel in the boiler body 1 can be stabilized, and the operation can be performed smoothly.

The method and apparatus for controlling the oxygen concentration of exhaust gas of an oxyfuel boiler system according to the present invention are not limited to the above-described illustrated examples, and various changes can be made without departing from the scope of the present invention. Of course.

[0024]

As described above, according to the method and the apparatus for controlling the exhaust gas oxygen concentration of the oxyfuel boiler equipment of the present invention, it is possible to prevent the oxygen concentration of the exhaust gas from becoming unstable, and the combustion of fuel in the boiler body is performed. Can be stabilized,
An excellent effect that driving can be performed smoothly can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an example of an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram illustrating an example of a general boiler.

FIG. 3 is a schematic configuration diagram showing a water supply / steam system of the boiler shown in FIG.

FIG. 4 is a schematic configuration diagram of an example of an oxyfuel boiler facility under development.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Boiler main body 31 Fan 34 Exhaust gas circulation line 39 Carbon dioxide recovery line 40 High-purity oxygen production device 42 Oxygen introduction damper 43 Inlet oxygen concentration 44 Inlet oxygen concentration meter 45 Outlet oxygen concentration 46 Outlet oxygen concentration meter 47 Outlet oxygen concentration set value 48 Control Command 49 Control command 50 Inlet oxygen concentration set value 51 Controller 54 Atmospheric flow control command 58 Exhaust gas circulation flow control command 61 Opening control command

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F23L 17/00 601 F23L 17/00 601H 17/16 17/16 B F23N 5/00 F23N 5/00 J

Claims (2)

[Claims] At the time of start-up, the atmosphere is introduced into the boiler main body to burn fuel into the atmosphere, and after the start-up is completed, exhaust gas is circulated while introducing oxygen supplied from the high-purity oxygen production apparatus into the boiler main body. This is a method for controlling the exhaust gas oxygen concentration of an oxyfuel boiler facility that performs oxyfuel combustion of the fuel and compresses and collects part of the exhaust gas with an increased carbon dioxide concentration. The flow rate of the atmosphere is adjusted to be equal to the outlet oxygen concentration set value, and after the start-up is completed, the flow rate of the oxygen supplied from the high-purity oxygen production apparatus is set so that the outlet oxygen concentration of the boiler body becomes equal to the outlet oxygen concentration set value. Exhaust gas oxygen concentration control of an oxyfuel boiler facility, wherein the exhaust gas circulation flow rate is adjusted so that the inlet oxygen concentration of the boiler body is equal to the inlet oxygen concentration set value. Law. 2. At the time of start-up, the air is introduced into the boiler main body by the operation of the fan to perform atmospheric combustion of the fuel, and after the start-up is completed, the oxygen supplied from the high-purity oxygen producing apparatus is supplied to the boiler main body by the oxygen introduction damper. Exhaust gas oxygen concentration in the oxyfuel boiler facility, in which the exhaust gas is circulated by the operation of a fan while being introduced by adjusting the opening degree, and oxyfuel combustion of the fuel is performed, and a part of the exhaust gas with an increased carbon dioxide concentration is compressed and recovered. A control device, comprising: an inlet oximeter for detecting the inlet oxygen concentration of the boiler body; an outlet oximeter for detecting the outlet oxygen concentration of the boiler body; Output a control command to the fan to adjust the air flow rate so that the outlet oxygen concentration is equal to the outlet oxygen concentration set value,
After the start-up is completed, a control command for adjusting the flow rate of oxygen supplied from the high-purity oxygen production apparatus is set so that the outlet oxygen concentration of the boiler body detected by the outlet oximeter becomes equal to the outlet oxygen concentration set value. A controller that outputs to the introduction damper and outputs a control command to the fan to adjust the exhaust gas circulation flow rate so that the inlet oxygen concentration of the boiler main body detected by the inlet oxygen concentration meter becomes equal to the inlet oxygen concentration set value. An exhaust gas oxygen concentration control device for an oxyfuel boiler facility, comprising: