WO2019049300A1

WO2019049300A1 - Combustion method

Info

Publication number: WO2019049300A1
Application number: PCT/JP2017/032407
Authority: WO
Inventors: 博昭谷川; 泰孝和田; 優大内; 輝夫田中
Original assignee: 中国電力株式会社
Priority date: 2017-09-08
Filing date: 2017-09-08
Publication date: 2019-03-14
Also published as: JPWO2019049300A1; JP6332578B1

Abstract

Provided is a combustion method that minimizes incomplete combustion and the generation of nitrogen oxides. In this combustion method, combustion is performed in a thermal power house 1 that generates electricity by combusting pulverized coal and ammonia in a boiler 6. The mixed burning ratio of the ammonia to the pulverized coal used in combustion in the boiler 6 is 0.8% or greater.

Description

Combustion method

The present invention relates to a combustion method.

Conventionally, a boiler of a power generation facility such as a thermal power plant generates high-temperature high-pressure steam using heat obtained by burning a fossil fuel such as coal, natural gas, light oil, heavy oil or the like with a burner. However, burning these fossil fuels generates carbon dioxide, which causes global warming. For this reason, in recent years there has been a move to curb carbon dioxide in the form of carbon credits (emission allowances).
For example, LNG (liquefied natural gas) produces less carbon dioxide than LPG (liquefied petroleum gas). For this reason, LNG is used as a fuel. Gas fuels, such as LNG, need to be liquefied for convenience in transportation. However, in the case of LNG, it is not easy to liquefy, and the cost of equipment also increases, because it is necessary to bring the temperature to a low temperature of about -180 degrees to liquefy.
For this reason, utilization of ammonia gas is proposed as fuel which does not generate carbon dioxide (for example, refer to patent documents 1). Ammonia liquefies at around -33 ° C. For this reason, for example, liquefaction is easy compared with LNG which requires about -180 degrees of liquefaction, and the cost of equipment is low.

JP, 2016-183840, A JP 2007-17030 A

However, when ammonia is burned, there is a concern that the nitrogen content contained in the ammonia component will be combined with oxygen to form nitrogen oxides.

Also, ammonia has a low burning rate, specifically, for example, where the burning rate of propane is 40 cm / s, the burning rate of ammonia is only 8 cm / s. For this reason, the flame when burning ammonia becomes long.
Therefore, in the case of co-firing ammonia with other fuels, for example, if a co-axial burner such as shown in FIG. 3 and FIG. Therefore, depending on the size and shape of the combustion space, incomplete combustion may occur.

Therefore, an object of the present invention is to provide a power generation facility and a combustion method that minimize the generation and incomplete combustion of nitrogen oxides.

In order to achieve the above object, the present invention has the following configuration.

(1) A combustion method implemented by a thermal power generation facility that generates power by burning pulverized coal and ammonia in a boiler, wherein the co-firing rate of ammonia used for combustion in the boiler with pulverized coal is 0.8 % Or more, the combustion method.

(2) The boiler includes a pulverized coal injection nozzle for injecting the pulverized coal, and an ammonia injection nozzle for injecting the ammonia, and the ammonia injection nozzle is for the pulverized coal injected from the pulverized coal injection nozzle When the cross section perpendicular to the longitudinal direction of the combustion flame is approximated to a circle, an injection port for injecting the ammonia may be provided in the tangential direction of the circle.

According to the present invention, it is possible to provide a power generation facility and a combustion method that minimize the generation of nitrogen oxides and the occurrence of incomplete combustion as much as possible.

It is the schematic of the power generation equipment of embodiment. It is a figure explaining a 4-stage burner. It is a figure explaining the example of composition of the burner of the highest rank. It is a figure explaining the example of composition of the burner of the highest rank. It is a figure explaining the example of composition of the burner of the highest rank. It is a figure which shows the amount of ammonia used for the combustion test. It is a figure which shows transition of the amount of coals used for the combustion test. It is a figure which shows the measurement location in a boiler exit. It is a figure which shows transition of the NOx amount in the boiler exit in a combustion test. Is a diagram showing the transition of CO ₂ content in the exhaust gas from the boiler.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[1. Constitution of the Invention]
Hereinafter, the thermal-power-generation installation 1 of embodiment of this invention is demonstrated. FIG. 1 is a schematic view of a thermal power plant 1 of the embodiment. The thermal power generation facility 1 of the embodiment is a system capable of combusting ammonia gas, but is a mixed-fired power generation facility 1 capable of combusting other than pulverized coal, oil, natural gas or ammonia gas such as BOG (boil off gas).

The thermal power generation facility 1 is a gas fuel supply that supplies gaseous fuel other than ammonia gas through the ammonia gas supply facility 2, the ammonia gas fuel piping facility 3, the boiler 6, the denitration facility 90, and the gas fuel piping 170. It comprises a unit 70 and a control unit 7 that controls the whole.

[Ammonia gas supply facility 2]
The ammonia gas supply facility 2 includes a storage tank 10, a vaporizer 20, an accumulator 30, an ammonia gas absorbing unit 80, and the like. The ammonia gas absorbing unit 80 is a water storage tank for absorbing ammonia gas emitted from the blow valve 81 or the like provided in the ammonia gas supply facility 2 into water.

(Storage tank 10)
The storage tank 10 stores pressurized and liquefied liquid ammonia, and is connected to the vaporizer 20 through a pipe 110. The pipe 110 is branched in two directions along the way. In one branched pipe 110a, a vaporizer start valve 11 and a vaporizer pressure control valve 12 for controlling the pressure in the vaporizer 20 are sequentially disposed from the upstream side. A vaporizer bypass valve 13 is disposed in the other branched pipe 110b.

(Vaporizer 20)
The vaporizer 20 heats and vaporizes the liquid ammonia supplied from the storage tank 10. In the vaporizer 20, liquid ammonia is heated through the inside of a coiled pipe immersed in warm water and vaporized to be ammonia gas. The downstream side of the vaporizer 20 is connected to the accumulator 30 via a pipe 120.
The pipe 120 is branched in two directions along the way. An accumulator start valve 21 and an accumulator pressure control valve 22 for controlling the pressure in the accumulator 30 are sequentially disposed from the upstream side in one branched pipe 120 a. An accumulator bypass valve 23 is disposed in the other branched pipe 120b.

(Accumulator 30)
The accumulator 30 is a device that accumulates ammonia gas and stabilizes the pressure. A pipe 130 extends from the downstream side of the accumulator 30. The pipe 130 is branched in two directions. One branched pipe 132 is connected to the header 40. The other branched pipe 131 is connected to the ammonia gas fuel pipe arrangement 3.

[Header 40]
The pipe 140 is connected to the downstream side of the header 40, and the pipe 140 is branched into a plurality of denitration pipes 141, 142, 143, and the denitration pipes 141, 142, 143 respectively have

denitration shutoff valves

41, 42, 43. It is connected to the denitrification equipment 90 through.

[DeNOx Equipment 90]
In the NOx removal facility 90, NOx removal pipes 141, 142 and 143 are connected to

NOx removal units

91, 92 and 93, respectively. The exhaust gas generated by combustion from the boiler 6 is fed into the

denitration devices

91, 92, 93, and ammonia is introduced from the piping of the denitration piping 141, 142, 143 in which the

denitration shutoff valves

41, 42, 43 are open. Using the gas as a reducing agent, nitrogen oxides in the exhaust gas are converted into harmless nitrogen gas and water.

[Ammonia gas fuel piping system 3]
As described above, the pipe 131 branched from the pipe 130 extending from the accumulator 30 is connected to the ammonia gas fuel pipe arrangement 3. A shutoff valve 31 is provided upstream of the pipe 131. On the downstream side of the shutoff valve 31, a purge pipe 133 extending from a purge gas supply unit 37 capable of flowing a purge gas such as nitrogen gas into the ammonia gas fuel piping installation 3 is connected via a purge valve 36.

The downstream side of the connection portion of the pipe 131 to which the purge pipe 133 is connected is branched in two directions. A pressure control valve 32 is disposed in one of the branched pipes 131a. A shutoff valve 33 is disposed in the other branched pipe 131b. The pipe 131 a and the pipe 131 b rejoin on the downstream side. The joined pipe 131 is connected to the flow meter 50 via the shutoff valve 34.

The flow meter 50 measures the flow rate of the gas flowing through the pipe 131. A pipe 150 extends from the downstream side of the flow meter 50. The piping 150 is branched in two directions along the way. A flow control valve 51 is disposed in one of the branched pipes 150a. A shutoff valve 52 is disposed in the other branched pipe 150b. The pipe 150 a and the pipe 150 b rejoin on the downstream side.

The downstream side of the joined pipe 150 is branched in two directions by the second connection portion 56.
One branched pipe is an ammonia gas outflow pipe 151 a, and is connected to the ammonia gas absorbing unit 80 of the ammonia gas supply facility 2 via an ammonia outflow blocking valve 55. As described above, the ammonia gas absorbing unit 80 is a water storage tank, and dissolves ammonia gas in water.
A burner valve 53 is disposed in the other branched ammonia gas supply pipe 151b. On the downstream side of the burner valve 53 in the pipe 150, a cooling pipe 160 to which cooling air is introduced is connected via a cooling air valve 61.
The ammonia gas outflow pipe 151 a may be branched downstream of the burner valve 53.
The downstream side of the ammonia gas supply pipe 151 b is connected to the first connection portion 72 of the gas fuel pipe 170 extending from the gas fuel supply unit 70 to the burner 62 A of the boiler 6 via the shutoff valve 54.

[Gas fuel supply unit 70]
The gas fuel supply unit 70 stores LNG (liquefied natural gas). When LNG is liquefied and stored, the LNG is vaporized by natural heat input from the outside, etc., and BOG off gas is generated. In the present embodiment, the gas fuel pipe 170 is a pipe that sends the BOG as a fuel to the burner 62A.
The gas fuel pipe 170 is connected to the burner 62 A of the boiler 6 at the downstream side of the first connection portion 72. A gas fuel pipe shutoff valve 71 is disposed upstream of the first connection portion 72 in the gas fuel pipe 170.

[Boiler 6]
In the boiler 6, a plurality of stages of burners 62 (four stages in the height direction in the present embodiment (

burners

62A, 62B, 62C, 62D) and a plurality of rows (four in each stage in the present embodiment) are arranged There is.
FIG. 2A is a view for explaining an arrangement example of the four-stage burners 62. In the present embodiment, coal (pulverized coal) is supplied as a fuel from the coal storage unit 75 to the four stages of

burners

62A, 62B, 62C, 62D. Gas fuel is further supplied to the topmost four burners 62A.

[Burner 62]
In FIG. 2A, the gas ring 171 provided at the tip of the gas fuel pipe 170 is arranged in an arc at the outermost part of each of the burners 62A, and the five burner nozzles 172 branch from the gas ring 171. An injection port 173 is provided at the tip of 172. Furthermore, ammonia is co-fired by injecting ammonia from one of the five injection ports 173 of the burner 62A located at the rightmost side in FIG. 2A.

FIG. 2B is a configuration example of the burner 62A present at the rightmost side in FIG. 2A, and more specifically, shows a layout diagram of each component when the burner 62A is viewed from the opposite side to the furnace.

A gas ring 171 is provided at the end of the gas fuel pipe 170, and five burner nozzles 172A to 172E branch from the gas ring 171. Further, the burner nozzle 172A is connected to the injection port 173A, the burner nozzle 172B to the injection port 173B, the burner nozzle 172C to the injection port 173C, the burner nozzle 172D to the injection port 173D, and the burner nozzle 172E to the injection port 173E.

Also, a pulverized coal burner nozzle 175 is provided at the center of the pentagon formed by the injection ports 173A to 173E so as to surround the heavy oil burner 174. Note that, hereinafter, the pulverized coal burner nozzle 175 may be referred to as "pulverized coal injection nozzle 175".

Further, in FIG. 2B, only one valve provided to the burner nozzle 172B is shown for convenience of explanation, but each of the burner nozzles 172A to 172E is provided with gas fuel piping shutoff valves 71A to 71E.

Further, the ammonia gas supply pipe 151b is connected to the burner nozzle 172B at the first connection portion 72 provided downstream of the gas fuel pipe shutoff valve 71B. As a result, supply of ammonia gas to the burner nozzle 172B, and consequently, mixed combustion of ammonia by the injection port 173B becomes possible. Hereinafter, the burner nozzle 172B may be referred to as "ammonia injection nozzle 172B".

The ammonia gas supply pipe 151 b is provided with the shutoff valve 54, the return pipe 176 is branched upstream of the shutoff valve 54, and the shutoff valve 177 is provided in the return pipe 176. The return pipe 176 is a pipe used when the ammonia gas is not supplied to the burner nozzle 172B from the ammonia gas supply pipe 151b. When the return gas is not supplied, the shutoff valve 54 is closed and the shutoff valve 177 is opened.
On the other hand, when ammonia gas is supplied to the burner nozzle 172B, as shown in FIG. 2B, the shutoff valve 54 is opened, and the gas fuel pipe shutoff valve 71B and the shutoff valve 177 are closed.

In the above, although the burner nozzle to which ammonia is supplied is one (172B) of the five burner nozzles 172 constituting the burner 62A, the embodiment of the present invention is not limited thereto. Ammonia may be supplied to any number of burner nozzles 172 among the plurality of burner nozzles 172 constituting the burner 62A.
Further, among the plurality of burners 62A provided in the uppermost stage of the boiler 6, not only the rightmost burner 62A but also any number of burners 62A may mix and burn ammonia.
More specifically, it is desirable to supply ammonia to one burner nozzle 172 not only in the rightmost burner 62A of the first stage but also in the other burners 62A. Furthermore, all the burners 62A, a total of four burners It is more desirable to supply ammonia to the five burner nozzles 172 at 62.
Furthermore, it is possible to mix and burn ammonia not only in the burner 62A but also in the burners 62B to 62D.

FIG. 2C is an example of a cross-sectional view of the burner 62 in the long axis direction, and the right side of FIG. 2C corresponds to the furnace side of the boiler 6. 2C, a burner nozzle 172B (ammonia injection nozzle 172B) connected to the gas ring 171 in the lower part has a heavy oil burner 174 at the center and a pulverized coal burner nozzle 175 (fine powder) so as to surround the heavy oil burner 174. There is a coal injection nozzle 175).

The burner nozzle 172B extends from the gas ring 171 in the direction opposite to the furnace and then bends to the furnace side, but the gas fuel pipe shut-off valve 71B is provided at the extension to the opposite side of the furnace and the first connection portion is bent 72 are provided. In the first connection portion 72, the ammonia gas supply pipe 151b is connected to the burner nozzle 172B. The burner nozzle 172B extends to the furnace side through the bent portion, and reaches the injection port 173B.
Ammonia gas is supplied from the ammonia gas supply pipe 151b to the injection port 173B through the first connection portion 72 and the extending portion of the burner nozzle 172B in the furnace direction, as shown by the arrow in FIG. 2C, and the injection port It is injected from 173B.

Also, pulverized coal is injected from the pulverized coal burner nozzle 175.

FIG. 2D shows a configuration example of the burner 62A viewed from the furnace side, and corresponds to the back side of the configuration example shown in FIG. 2B. Also, in FIG. 2D, solid arrows indicate the flow of ammonia gas, and solid circles indicate the contour of a cross section perpendicular to the length direction of the pulverized coal flame.

Repeating the above, the shutoff valve 54 provided in the ammonia gas supply pipe 151b is opened, and the gas fuel pipe shutoff valve 71B provided in the burner nozzle 172B and the shutoff valve 177 provided in the return pipe 176 are closed. As a result, the ammonia gas is supplied to the injection port 173B via the ammonia gas supply pipe 151b, the first connection portion 72, and the burner nozzle 172B. Furthermore, when the cross section perpendicular to the length direction of the pulverized coal flame injected from the pulverized coal burner nozzle 175 is approximated to a circle, as shown by the arrow in FIG. 2D, the injection port 173B is tangential to this circle. Ammonia is injected into the

Ammonia is injected so as to draw a spiral locus around the pulverized coal flame, and the combustion distance of the ammonia is increased, whereby the combustion time of the ammonia is secured and the ammonia can be completely burned.

[2. Combustion test]
In the thermal power generation facility 1 whose configuration has been described in the above “1. Configuration of the invention”, the following combustion test was conducted by ammonia mixed combustion.

As shown in FIG. 3, the test period is 7 days, from 13 o'clock to 17 o'clock on the first day, from 10 o'clock to 17 o'clock on the second day to 6 o'clock, and from 10 o'clock to 13 o'clock on the seventh day In the above, a maximum of 450 kg / h of ammonia (note that this is the maximum flow rate of the vaporizer 20 and corresponds to 400 kg of coal) was used.
More specifically, 100 kg / h of ammonia is burned from 13 o'clock to 15 o'clock on the first day, and 200 kg / h of ammonia is burned from 15 o'clock to 16 o'clock on the first day. From the hour to 17: 00, 400 kg / h of ammonia was burned, and from the second day on, 450 kg / h of ammonia was burned.
Also, basically, the combined combustion rate of ammonia was about 0.6% (equivalent to 1 MW) because the boiler was operated at a load of 155 MW, but on the fifth day only, the boiler was operated at a load of 120 MW The mixed combustion rate of ammonia was about 0.8%. In addition, ammonia was burned in the range where there is no excess of exhaust gas.
In addition, liquid ammonia used for combustion has a purity of 99.98%, water content of 0.016%, and an oil content of less than 1.0 ppm, and coal species co-fired with ammonia is 60% for mount oren, and Bocabri premium Is 40%.

[2.1 Boiler metal temperature]
The temperature of the metal portion of the piping or the like provided in the boiler 6, that is, the boiler metal temperature was measured at the time of coal-only combustion and at the time of mixed combustion of ammonia and coal. There are six measurement points: a primary superheater outlet, a reheater outlet, a secondary superheater inlet, a secondary superheater middle, and a secondary superheater outlet.

As a result of the measurement, when the load of the boiler is 155 MW, the boiler metal temperature at the primary superheater outlet is 400 to 450 ° C, the boiler metal temperature at the reheater outlet is 500 to 550 ° C, and the boiler heat at the secondary superheater inlet The metal temperature is 400 to 450 ° C, the boiler metal temperature in the middle of the secondary superheater is 450 to 500 ° C, and the boiler metal temperature at the outlet of the secondary superheater is 500 to 600 ° C. With time, there was almost no change.

Similarly, when the load on the boiler is 120 MW, the boiler metal temperature at the primary superheater outlet is 400 to 450 ° C, the boiler metal temperature at the reheater outlet is 500 to 600 ° C, and the boiler metal at the secondary superheater inlet The temperature is 400 to 450 ° C, the boiler metal temperature in the middle of the secondary superheater is 450 to 550 ° C, and the boiler metal temperature at the outlet of the secondary superheater is 500 to 600 ° C. And there was almost no change.

That is, in the temperature distribution in the boiler 6, the effect of co-firing ammonia with coal was hardly observed.

[2.2 Coal amount evaluation]
FIG. 4 shows the amount of used coal per hour before and after mixed combustion, and the difference between the amounts of coal used. In addition, the table of (b) shows the numerical value used by the graph of (a) in a tabular form, and the table of (c) shows the average value of the day shown by the leftmost column in (c).

The reduction in the amount of coal used after co-firing compared to before co-firing was 0.50 T / h on average for 7 days. That is, 450 kg / h of the amount of ammonia combustion became almost the same as 500 kg / h (anhydrous) of the amount of reduction of coal. Also, comparing the 1st to 7th days, the amount of reduction of coal on the 5th day became the maximum value of 1.96T / h. As mentioned above, the coal type of coal used for the combustion is 60% of Mount Oen and 40% of Boca-Bri Premium.

[2.3 boiler outlet NOx value]
ECO (economizer) at a total of 48 points at the boiler outlet 24 points A and 24 points B as indicated by the cross in the sectional views shown in [system A] and [system B] in FIG. 5 The NOx value of the outlet gas was measured.
FIG. 6 shows the NOx values at the boiler outlet before and after co-firing. In addition, since adjustment of various devices was performed on the 1st day and the NOx meter was checked on the 3rd day, it is excluded from the data. Also, the table of (b) shows the numerical values used in the graph of (a) in tabular form, and the table of (c) shows the power plant output, the mixed combustion rate, and the leftmost column in (c) Mean of the difference between Further, the value before mixed combustion is a value 30 minutes before the injection of ammonia, and the value after mixed combustion is an average value of data of 4 to 5 points taken every 30 minutes after the injection of ammonia.

On the 5th day that the rate of mixed combustion of ammonia is about 0.8%, while the rate of mixed combustion of ammonia increased from about 0.6% to about 0.8%, compared to other days, mixed burning It was confirmed that the NOx value at the boiler outlet later decreased more than before mixed combustion.
In addition, on the second, fourth, sixth, and seventh days, the rate of increase in the NOx value after mixed combustion compared with that before mixed combustion is not stable, at which the ratio of mixed combustion of ammonia is about 0.6%. Along with that, the average value showed a positive value of 0.17 ppm, while the increase in NOx value after mixed combustion compared to before mixed combustion on the fifth day when the mixed ratio of ammonia was about 0.8% The amount was confirmed to be a negative value of -13.75 ppm.
Thus, when ammonia is co-fired with coal, it is desirable that the ammonia co-firing rate be 0.8% or more, and it is suggested that the NOx value can be reduced as the ammonia supply amount is increased.
this is,
4NO + 4NH ₃ + O ₂ → 4N ₂ + 6H ₂ O
It is presumed that the noncatalytic denitrification reaction has progressed as shown in the chemical reaction formula.

[2.4 boiler outlet ammonia concentration]
As shown in FIG. 5, when the ammonia concentration of the ECO (carbon economizer) outlet gas was measured at a total of 10 points at the boiler outlet, the ammonia concentration before ammonia injection into the fuel is 0.3 ppm, and The ammonia concentration after the ammonia injection was 0.1 to 0.4 ppm. That is, even after the ammonia injection into the fuel, almost no ammonia remained at the boiler outlet, and it was confirmed that the ammonia was completely burned.
This is because ammonia is injected in the tangential direction of the pulverized coal flame so that the ammonia draws a spiral locus around the pulverized coal flame, and the combustion time of the ammonia is secured by taking a long combustion distance of the ammonia. It is estimated that

[2.5 CO ₂ analysis]
As shown in FIG. 5, the composition of the exhaust gas from the boiler was measured at two points at the outlet of the boiler. FIG. 7 shows the output of the boiler, the amount of injected ammonia, and the amount of CO _{2 in} the exhaust gas from the boiler. The table of (b) shows the numerical values used in the graph of (a) in the form of a table.
Where the initial amount of CO ₂ is 12.8%, the mixed combustion rate of ammonia is 0.6% to 0.8%, so the amount of CO ₂ is only about 0.1% which is the product of those numbers. It was not expected to decrease, but in practice it decreased by 0.2 to 1.3%.
Moreover, the annual carbon dioxide reduction amount in the case where the mixed combustion rate is about 0.6% is about 3.99 (thousand t-CO ₂ / year), and the annual carbon dioxide in the case where the mixed combustion rate is about 0.8% The reduction amount was about 4.12 (thousand t-CO ₂ / year). (In calculation, the carbon dioxide emission factor was calculated using the emission factor by electric power company in FY 2015 (China Electric Power: 0.0007t-CO ₂ / kWh) and the facility operation rate was 70%. Since it is possible to burn all mixed ammonia in the boiler, it is considered that carbon dioxide emissions can be reduced according to the ratio of mixed combustion.

As described above, the present embodiment has the following effects.
(1) The combustion method of the present embodiment is a combustion method executed by the thermal power generation facility 1 that generates power by burning pulverized coal and ammonia in the boiler 6, and the fine powder of ammonia used for combustion in the boiler 6 The rate of co-firing with charcoal is at least 0.8%.
According to the present embodiment, the ammonia used for the combustion simultaneously has an effect of denitrifying NOx in the exhaust gas generated by the combustion, so that the ammonia can be effectively used.

(2) Further, in the combustion method of the present embodiment, the boiler 6 includes a pulverized coal burner nozzle 175 for injecting pulverized coal, and an ammonia injection nozzle 172B for injecting ammonia, and the ammonia injection nozzle 172B is a pulverized coal burner nozzle When the cross section perpendicular to the longitudinal direction of the combustion flame of the pulverized coal injected from 175 is approximated to a circle, an injection port 173B for injecting ammonia is provided in the tangential direction of this circle.
According to this embodiment, ammonia is injected so as to draw a spiral trajectory around the pulverized coal flame, and the combustion distance of the ammonia is increased, whereby the combustion time of the ammonia is secured and the ammonia is completely burned.

DESCRIPTION OF SYMBOLS 1 Thermal power generation installation 2 Ammonia gas supply installation 3 Piping installation for ammonia gas fuel 6 Boiler 7 Control part 10 Storage tank 11 Vaporizer start valve 12 Vaporizer pressure control valve 13 Vaporizer bypass valve 20 Vaporizer 21 Accumulator start valve 22 Accumulator pressure Regulator valve 23 Accumulator bypass valve 30

Accumulator

31, 33, 34, 52, 54 Shut-off valve 32 Pressure regulator valve 36 Purge valve 37 Gas supply unit for purge 40 Header 50 Flow meter 51 Flow regulator valve 53 Burner valve 55 Ammonia outflow cutoff valve 60A Burner 61 Cooling air valve 62

Burner

62A, 62B, 62C, 62D Gas burner 70 Gas

fuel supply unit

71, 71B Gas fuel piping shutoff valve 72 First connection unit 80 Ammonia gas absorption unit 90

Denitrification equipment

110, 11 a, 110b, 120, 120a, 120b, 130, 131, 131a, 131b, 132, 140, 150, 150a, 150b Piping 133 Purge piping 151a Ammonia gas outflow piping 151b Ammonia supply piping 160 Cooling piping 170 Gas fuel piping 171

Gas ring

172, 172A, 172B, 172C, 172D,

172E Burner nozzle

173, 173A, 173B, 173C, 173D, 173E Injection port 174 Heavy oil burner 175 Pulverized coal burner nozzle 176 Return piping 177 Shutoff valve

Claims

A combustion method performed by a thermal power generation facility that generates power by burning pulverized coal and ammonia in a boiler,
The combustion method, wherein the mixed combustion rate of ammonia used for combustion in the boiler with pulverized coal is 0.8% or more.
The boiler includes a pulverized coal injection nozzle for injecting the pulverized coal, and an ammonia injection nozzle for injecting the ammonia,
The ammonia injection nozzle injects the ammonia in the tangential direction of the circle when the cross section perpendicular to the longitudinal direction of the combustion flame of the pulverized coal injected from the pulverized coal injection nozzle is approximated to a circle The combustion method according to claim 1, comprising a mouth.