JP2000213370A - Gasification control device for gasification combined cycle power plant - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To suppress a change in furnace temperature even when the concentration of oxygen supplied to a gasifier changes. SOLUTION: An oxygen concentration detector 22 for detecting an oxygen concentration is provided in a path of an oxygen gas pipe 7. Further, there is provided an oxygen concentration predictor 23 for calculating an oxygen concentration prediction value using the oxygen concentration prediction model. The oxygen concentration signal detected by the oxygen concentration detector 22 is input to the oxygen concentration estimator 23.
Further, the operating parameters from the oxygen production equipment 5 are input to the oxygen concentration estimator 23. The oxygen concentration predicted value obtained by the oxygen concentration predictor 23 is supplied to the controller 21 for obtaining the set value of the gasification raw material flow rate and the set value of the oxygen flow rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combined gasification combined cycle power plant, and more particularly, to a stable gasification condition by suppressing a change in the furnace temperature due to a change in the concentration of oxygen supplied to a gasification furnace. The present invention relates to a gasification control device of a combined gasification combined cycle power plant that can be held.

[0002]

2. Description of the Related Art In a gasification furnace of a combined gasification combined cycle power plant, a pulverized coal or a slurry in which pulverized coal and water are mixed,
Alternatively, oxygen as a gasifying agent is mixed with a gasification raw material such as waste oil of a chemical process or a low-quality heavy oil such as an oligomer, and a crude gas is generated through incomplete combustion and a chemical reaction process.

In this case, the atomic ratio (O / C ratio) between carbon (C) in the gasification raw material and oxygen (O) in the oxygen is about 1
Thus, the flow rates of the gasification raw material and oxygen flowing into the gasification furnace are adjusted by the respective control valves, and the flow rates are adjusted based on the set values so as to keep the furnace temperature at a desired temperature.

FIG. 4 shows an example of a gasification furnace provided with this flow control means. The gasification raw material flows into the gasification furnace 3 from the gasification raw material supply equipment 1 through the gasification raw material pipe 2.
At this time, the flow rate of the gasification raw material is adjusted by controlling the opening of the gasification raw material control valve 4. Oxygen generated in the oxygen production equipment 5 is pressurized to a predetermined pressure by the compressor 6 and flows into the gasification furnace 3 through the oxygen gas pipe 7. At this time, the flow rate of oxygen is controlled by controlling the opening of the oxygen control valve 8.

[0005] The crude gas generated in the gasifier 3 is at a high temperature,
The heat is recovered by the gas cooler 9. Thereafter, the crude gas whose temperature has dropped is sent to the gas purification facility 10, where the crude gas is cooled.
Impurities such as sulfur are removed and supplied to a combustor of a gas turbine (not shown). Nitrogen gas, which is a by-product of the oxygen production equipment 5, is used for soot blowing of the gas cooler 9. A compressor 12 is provided in the path of the nitrogen gas pipe 11 to compress the nitrogen gas.

Gasification raw material value control valve 4 and oxygen control valve 8
Is equipped with a controller 13 for controlling the ratio of both gas flow rates. The flow rate of the gasification raw material flowing through the gasification raw material pipe 2 is the flow meter 1
4, the flow rate of oxygen flowing through the oxygen gas pipe 7 is detected by a flow meter 15, and is input to a controller 13. The temperature inside the furnace of the gasification furnace 3 is detected by a temperature detector 16. Given to. This controller 13
Is connected to the console 17 of the control room. As shown in FIG. 5, the respective detection amounts are displayed on the display of the console 17 together with the set values.

[0007]

A method of controlling the gas flow ratio to keep the O / C ratio constant tends to make the transient response in following the load change unstable. This is due to the fluctuation of the oxygen concentration caused by the characteristics of the oxygen production equipment 5. That is, even if the flow rate ratio is controlled because the oxygen concentration changes, the O / C ratio does not become constant, and as a result, the furnace temperature of the gasification furnace 1 largely fluctuates.

Further, the temperature detector 16 must detect the temperature in the furnace under a high-temperature atmosphere. However, under such conditions, the deterioration is remarkably advanced, and the temperature cannot be detected accurately. In particular, the current one is not sufficient for monitoring the temperature around the burner section where the temperature may change due to the fluctuation of the oxygen concentration.

Until now, there has been no means for effectively coping with a change in the furnace temperature caused by a change in the oxygen concentration, and there is a concern that the life of the gasification furnace 3 may be significantly impaired.

It is an object of the present invention to provide a gasification control device which suppresses a change in the furnace temperature even when the concentration of oxygen supplied to the gasification furnace changes.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a gasification raw material control valve for controlling a flow rate of a gasification raw material supplied to a gasification furnace, and a method for controlling a flow rate of oxygen supplied to the gasification furnace. An oxygen control valve to be adjusted, and a command signal for determining the degree of opening of the gasification material control valve based on the difference between the gasification material flow signal and the flow rate set value is output. And a controller for outputting a command signal for determining the opening of the oxygen control valve based on the oxygen concentration predictor, wherein the oxygen concentration predictor calculates a predicted value of the concentration of oxygen supplied to the gasifier using the oxygen concentration prediction model. Is provided.

In the gasification control device having the above configuration, the set values of the gasification raw material and the oxygen flow rate can be changed in accordance with the predicted oxygen concentration value.
A change in the furnace temperature of the gasification furnace can be suppressed.

Further, the present invention desirably includes an oxygen concentration detector for detecting the concentration of oxygen supplied to the gasification furnace.

In such a gasification control device, it is possible to correct the oxygen concentration prediction value using the detected oxygen concentration signal, and to perform more detailed gasification control while keeping the furnace temperature constant. it can.

Further, according to the present invention, it is possible to provide an oxygen detector for detecting the concentration of oxygen in the gasifier, instead of the oxygen concentration predictor.

In the gasification control device having the above configuration, the set values of the gasification raw material and the oxygen flow rate can be changed in accordance with the detected oxygen concentration signal. Can be suppressed from changing.

Further, the present invention desirably includes a nitrogen gas system having a nitrogen injection valve for introducing nitrogen gas into the gasification furnace.

In such a gasification control device, when the oxygen concentration exceeds the set concentration, the nitrogen injection valve is opened to inject nitrogen gas not directly related to the reaction into the gasification furnace to change the flow rate ratio. Let it. Thus, even when the oxygen concentration temporarily increases, the flow rate ratio changes by injecting the nitrogen gas, and it is possible to reliably prevent the furnace temperature from excessively increasing.

[0019]

Embodiments of the present invention will be described with reference to the drawings. In FIG. 1, flow rate signals from a flow meter 14 for detecting a gasification raw material flow rate and a flow meter 15 for detecting an oxygen flow rate are input to a controller 21. Further, an oxygen concentration detector 22 for detecting the oxygen concentration is provided in the path of the oxygen gas pipe 7. Further, there is provided an oxygen concentration estimator 23 for calculating an oxygen concentration prediction value using the oxygen prediction model. This oxygen concentration prediction model can determine the oxygen concentration according to a predetermined algorithm.
The oxygen concentration signal detected by the oxygen concentration detector 22 is input to the oxygen concentration estimator 23. Further, the operating parameters from the oxygen production equipment 5 are input to the oxygen concentration estimator 23.
The oxygen concentration predicted value obtained by the oxygen concentration predictor 23 is supplied to the controller 21 for obtaining a gasification raw material set value and an oxygen flow rate set value.

The present embodiment has the above-described configuration. During the operation of the plant, the oxygen production equipment 5
Each operation parameter is input from. Oxygen concentration predictor 2
When these parameters are given to 3, the oxygen concentration prediction model determines the oxygen concentration, and this value is input to the controller 21 as the oxygen concentration prediction value.

When a value relating to the oxygen concentration is inputted to the controller 21, the gasification raw material flow rate setting value and the oxygen flow rate setting value are determined in consideration of the variation of the oxygen concentration in order to keep the O / C ratio constant. In response to this, the openings of the gasification material control valve 4 and the oxygen control valve 8 are controlled such that the deviation between the gasification material flow rate signal and the oxygen flow rate signal becomes zero.

The predicted oxygen concentration value is corrected in real time by the actual oxygen concentration signal provided from the oxygen concentration detector 22 and input to the controller 21. In response to this, the values of the gasification raw material control valve 4 and the oxygen control valve 8 are adjusted. The opening changes immediately. As a result, finer gasification control can be achieved while keeping the furnace temperature constant.

Thus, in the present embodiment, it is possible to avoid the danger that the temperature of the gasification furnace 3 will rise excessively. On the contrary, it is possible to prevent the temperature from excessively decreasing.

FIG. 2 shows the detected amounts and set values displayed on the display of the console 17 according to the present embodiment.

In this embodiment, the gasification raw material flow rate setting value and the oxygen flow rate setting value are changed by the controller 21 in accordance with the oxygen concentration signal from the oxygen concentration detector 22 instead of the oxygen concentration prediction value. Good.

According to the present embodiment, even when the concentration of oxygen generated in the oxygen production facility 5 fluctuates, it is possible to suppress a change in the furnace temperature of the gasification furnace 3.

Further, different embodiments of the present invention will be described. In FIG. 3, a nitrogen injection valve 24 is provided in a path of the nitrogen gas pipe 11. Further, a flow meter 25 for measuring a flow rate is provided in the nitrogen gas pipe 11. This flow meter 2
The flow signal measured at 5 is input to the controller 21. Further, the controller 21 is configured to output a command signal for opening the nitrogen injection valve 24 when the oxygen concentration predicted value obtained by the oxygen concentration predictor 23 exceeds a predetermined value.

This embodiment has the above-described configuration. If the concentration of oxygen generated in the oxygen production equipment 5 increases for some reason during the operation of the plant, the oxygen concentration signal from the oxygen concentration detector 22 greatly changes. When the oxygen concentration signal exceeds a predetermined value, the controller 21 outputs an open command signal to the nitrogen injection valve 24. Therefore, the nitrogen injection valve 24 is fully opened, and a part of the nitrogen gas flowing through the nitrogen gas pipe 11 flows into the gasification furnace 3. At this time, the temperature inside the gasification furnace 3 becomes high due to the increase in the oxygen concentration, but the temperature starts to gradually decrease due to the inflow of the nitrogen gas, and reaches a desired temperature with the passage of time.

As described above, even when the oxygen concentration temporarily increases, by introducing the nitrogen gas which is not directly involved in the reaction,
The flow ratio changes, and it is possible to reliably suppress the furnace temperature from excessively increasing.

The injection of the nitrogen gas in the present embodiment utilizes a part of the nitrogen for soot blowing, and the flow meter 25 measures the amount of the injected nitrogen. Further, a command signal to the nitrogen injection valve 24 may be output when the conditions of both the increase in the oxygen concentration and the increase in the furnace temperature are satisfied using the output signal of the temperature detector 16.

In this embodiment, the display of the console 17 also displays the oxygen concentration threshold value and the flow rate of the injected nitrogen.

According to the present embodiment, even when the oxygen concentration temporarily increases, the flow rate ratio is changed by injecting the nitrogen gas, thereby reliably preventing the furnace temperature from excessively increasing. Can be.

[0033]

According to the present invention, since the oxygen concentration estimator for calculating the predicted value of the concentration of oxygen supplied to the gasification furnace is provided, when the concentration of oxygen generated in the oxygen production equipment fluctuates. In addition, it is possible to suppress a change in the furnace temperature of the gasification furnace, and to prevent the life of the gasification furnace from being impaired.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a gasification control device of a combined gasification cycle power plant according to the present invention.

FIG. 2 is a diagram showing a display example of a console according to the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the present invention.

FIG. 4 is a system diagram showing an example of a conventional combined gasification cycle power plant.

FIG. 5 is a diagram showing a display example of a conventional console.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 3 Gasifier 4 Gasification raw material control valve 5 Oxygen production equipment 8 Oxygen control valve 9 Gas cooler 14, 15, 25 Flow meter 21 Controller 22 Oxygen concentration detector 23 Oxygen concentration predictor

Claims (4)

[Claims] 1. A gasification raw material control valve for controlling a flow rate of a gasification raw material supplied to a gasification furnace, an oxygen control valve for controlling a flow rate of oxygen supplied to the gasification furnace, a gasification raw material flow rate signal, A command signal for determining an opening degree of the gasification raw material control valve based on a deviation from the flow rate set value, and a command for determining an opening degree of the oxygen control valve based on a deviation between the oxygen flow rate signal and the flow rate set value. A controller for outputting a signal, wherein an oxygen concentration predictor for calculating a predicted value of the concentration of oxygen supplied to the gasifier using an oxygen concentration prediction model is provided, and the gasification raw material in the controller is provided. A gasification control device for a gasification combined cycle power plant, wherein a set value of oxygen flow and an oxygen flow rate set value are changed in accordance with an oxygen concentration predicted value from the oxygen concentration predictor. 2. An oxygen concentration detector for detecting the concentration of oxygen supplied to the gasifier is provided, and an oxygen concentration predicted value is corrected using an oxygen concentration signal from the oxygen concentration detector. The gasification control device for a combined gasification cycle power plant according to claim 1, characterized in that: 3. An oxygen concentration detector for detecting the concentration of oxygen in the gasifier is provided in place of the oxygen concentration predictor,
The gasification control device for a combined gasification cycle power plant according to claim 1, wherein the set values of the gasification raw material and the oxygen flow rate in the controller are changed in accordance with an oxygen concentration signal from the oxygen concentration detector. 4. A nitrogen gas system having a nitrogen injection valve for introducing nitrogen gas into the gasification furnace is provided, and when the oxygen concentration exceeds a set concentration, the nitrogen injection valve is opened to release the nitrogen gas. 4. The gasification control apparatus for a gasification combined cycle power plant according to claim 1 or 3, wherein the gasification furnace is injected into the gasification furnace to change a flow ratio.