JPH04359703A - Method for controlling desulfurization rate in fluidized-bed boiler - Google Patents

Abstract

PURPOSE:To provide a high responsiveness to changes in load, etc., and obviate to provide a nozzle for exclusively injecting desulfurizing agent. CONSTITUTION:A fuel 6 and a desulfurizing agent 8 are fed to each of first and second tanks 30, 31 for slurry of fuel mixture, where a first slurry of fuel mixture 33 and a second slurry of fuel mixture 36 are prepared in different mixing ratios and supplied to a fluidized bed 17 through each of first and second nozzles 45, 46 for injecting fuel mixture respectively by pumps 42, 43 and in quantities as desired for the control of the desulfurization rate.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling desulfurization rate in a fluidized bed boiler.

0002

[Prior art] In recent years, with the aim of increasing the efficiency of thermal power generation,
Research and development is underway on combined power generation equipment using fluidized bed boilers.

As shown in FIG. 2, the fluidized bed boiler 18 includes a cell 3 containing an evaporator 5, a superheater 1, and a reheater 2, and a pressure vessel 7 containing the cell 3. 3
A predetermined amount of bed material 4 is placed inside.

The upstream end of the superheater 1 in the direction of steam flow is connected to the water supply pump 9 via the evaporator 5 via a pipe 19, and the downstream end is connected to the steam inlet of the high pressure turbine 11 of the steam turbine equipment 10 through the pipe 20. The upstream end of the reheater 2 in the steam flow direction is connected to the steam turbine equipment 10 by a pipe line 21.
At the steam outlet of the high pressure turbine 11, the downstream end is connected to the pipe 2.
2 is connected to the steam inlet of the medium and low pressure turbine 12 of the steam turbine equipment 10, and furthermore, the steam outlet of the medium and low pressure turbine 12 is connected to the feed water pump 9 via the condenser 13 by a pipe 23. There is.

In the fluidized bed boiler 18 described above, compressed air obtained by compressing the atmosphere 15 by the compressor 14 is supplied from the compressed air supply pipe 16 to the pressure vessel 7 to form a fluidized bed 17 of the bed material 4 in the cells 3. Furthermore, fuel (coal) is supplied to the fluidized bed 17 and burned within the fluidized bed 17.

When fuel burns, its thermal energy is
The thermal energy is transferred to the bed material 4 in a fluidized state, and the bed material 4 further contacts the evaporator 5, superheater 1, and reheater 2, so that the thermal energy is transferred to the evaporator 5, superheater 1, and reheater 2 is transmitted to.

[0007] Boiler water supplied from the feed water pump 9 to the evaporator 5 is vaporized by the thermal energy, and the steam is turned into superheated steam by the superheater 1, and the superheated steam flows into the high pressure turbine 11 of the steam turbine equipment 10. The high pressure turbine 11 is driven.

The steam after driving the high pressure turbine 11 is
The steam that flows into the reheater 2 and is reheated by the reheater 2 flows into the medium and low pressure turbine 12.
2 and further drives the medium and low pressure turbine 12 , the steam is returned to boiler water by the condenser 13 and is again supplied to the evaporator 5 by the water supply pump 9 .

In this way, the steam turbine equipment 10 is driven by steam, and the steam turbine generator 24 connected to the steam turbine equipment 10 generates electricity.

On the other hand, the combustion gas of the fuel burned in the cell 3 is supplied to a gas turbine 26 through a pipe 25, then exhausted from a chimney 28, and is then generated by a gas turbine generator 27 connected to the gas turbine 26. Electric power is generated, and at the same time, the compressor 14 is driven by the gas turbine 26.

In the fluidized bed boiler 18 as described above, when intrabed desulfurization is performed to reduce the sulfur content contained in the combustion gas, as shown in FIG. 2, the fuel 6 and limestone (C
A mixed fuel slurry tank 2 with a desulfurizing agent 8 such as aCO3)
9 at a desired ratio to form a mixed fuel slurry 32 in advance, and then supplying the mixed fuel slurry 32 into the fluidized bed 17 from a plurality of mixed fuel injection nozzles 44 using a pump 39.

Further, as shown in FIG. 3, the fuel 6 is charged into the fuel slurry tank 35 to form a fuel slurry 37, and the desulfurizing agent 8 is charged into the desulfurizing agent slurry tank 36 to form a desulfurizing agent slurry 38. and the fuel slurry 3
7 and the desulfurizing agent slurry 38 are supplied into the fluidized bed 17 through a plurality of fuel injection nozzles 47 and desulfurizing agent injection nozzles 48 by pumps 40 and 41, respectively, and mixed within the fluidized bed 17.

[0013]

[Problems to be Solved by the Invention] In the method of supplying a pre-formed mixed fuel slurry 32 into the fluidized bed 17 as shown in FIG.
When it becomes necessary to temporarily change the ratio of the fuel 6 and the desulfurizing agent 8, the required amount of the fuel 6 and the desulfurizing agent 8 are once added to the mixed fuel slurry tank 29 to increase or decrease the ratio of the fuel 6 and the desulfurizing agent 8 in the mixed fuel slurry 32. After that, it has to be injected into the fluidized bed 17, which has the disadvantage of poor response.

[0014] In this case, the fluidized bed 17
It has been empirically found that the desulfurization rate tends to decrease within the tank, and as mentioned above, it is necessary to always keep a large amount of desulfurization agent 8 in consideration of the poor response to load changes, etc., which is wasteful. There were many.

On the other hand, as shown in FIG.
7 and the desulfurizing agent slurry 38 into the fluidized bed 17 separately, the response to load changes is good, but because the desulfurizing agent slurry 38 is injected into the fluidized bed 17 completely separately from the fuel injection nozzle 47 It was necessary to provide a desulfurizing agent injection nozzle 48, and the number of nozzles had to be increased.

In view of the above circumstances, the present invention aims to provide a method for controlling the desulfurization rate in a fluidized bed boiler, which has good responsiveness to changes in load and does not require a separate injection nozzle exclusively for the desulfurization agent. It is something.

[0017]

[Means for Solving the Problems] The present invention prepares a plurality of types of mixed fuel slurries with different ratios of fuel and desulfurizing agent, and supplies each mixed fuel slurry at a different flow rate to a fluidized bed boiler to desulfurize the slurry. It is characterized by adjusting the rate.

[0018]

[Operation] Therefore, when it is necessary to temporarily change the ratio of fuel and desulfurization agent such as when the load changes, it is possible to change the flow rate of multiple types of mixed fuel slurry and supply them into the fluidized bed. The mixed fuel slurry is mixed in the fluidized bed, the ratio of fuel and desulfurization agent is adjusted to a desired value, and the desulfurization rate in the fluidized bed is adjusted.

[0019]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows one embodiment of the present invention, in which parts with the same reference numerals as in FIGS. 2 and 3 represent the same parts, and the fuel 6 and desulfurization agent 8 are The first mixed fuel slurry 33 is charged into the slurry tank 30 and has a desired ratio.
At the same time, the fuel 6 in the first mixed fuel slurry 33 is charged into the second mixed fuel slurry tank 31.
A second mixed fuel slurry 34 having a desired ratio different from that of the desulfurizing agent 8 is formed, and the first mixed fuel slurry 33 and the second mixed fuel slurry 34 are pumped through a pump 42,
43, the mixed fuel is supplied into the fluidized bed 17 from the first mixed fuel injection nozzle 45 and the second mixed fuel injection nozzle 46.

When it becomes necessary to temporarily change the ratio of the fuel 6 and the desulfurizing agent 8, such as when the load changes, the pump 42,
43, the first and second mixed fuel slurries 33 and 34 having different ratios of fuel 6 and desulfurizing agent 8 are respectively injected into the fluidized bed 17 from the first and second mixed fuel injection nozzles 45 and 46. The ratio of the fuel 6 and the desulfurizing agent 8 is adjusted to a desired value, and the desulfurization rate within the fluidized bed is adjusted.

[0022] In this way, responsiveness to changes in load etc. is improved, and there is no need to always add a large amount of desulfurizing agent 8 as in the case of the conventional example shown in FIG. There is no need to provide a separate injection nozzle for the desulfurization agent and the injection nozzle for the fuel, as in the case of the example, and there is no need to increase the number of nozzles.

The method for controlling the desulfurization rate in a fluidized bed boiler according to the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various changes can be made without departing from the gist of the present invention. be.

[0024]

As explained above, according to the desulfurization rate control method in a fluidized bed boiler of the present invention, responsiveness to changes in load, etc. is improved, and an injection nozzle dedicated to desulfurization agent is provided separately from that for fuel. An excellent effect can be achieved in that there is no need to increase the number of nozzles.

[Brief explanation of the drawing]

FIG. 1 is a conceptual diagram of an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a conventional example.

FIG. 3 is a conceptual diagram of another conventional example.

[Explanation of symbols]

6. Fuel 8 Desulfurization agent 18 Fluidized bed boiler

Claims (1)

[Claims] [Claim 1] A plurality of types of mixed fuel slurries having different ratios of fuel and desulfurizing agent are prepared, and each mixed fuel slurry is supplied to a fluidized bed boiler at a different flow rate to adjust the desulfurization rate. A method for controlling the desulfurization rate in a fluidized bed boiler.