KR102628440B1 - Combustion control system and method - Google Patents

Abstract

The present invention relates to a gas turbine combustion device that supplies exhaust gas generated through a combustion operation using oxygen and supercritical carbon dioxide to a turbine. Flame and the exhaust gas are generated by burning oxygen and the circulating gas that has passed through the turbine. Combustion area; and a dilution area where the exhaust gas flows in to dilute incomplete combustion gas contained in the exhaust gas and cool the temperature of the exhaust gas to the operating temperature of the turbine.

Description

Gas turbine combustion device { COMBUSTION CONTROL SYSTEM AND METHOD }

The present invention relates to a gas turbine combustion device that supplies gas to a turbine.

Unlike existing power generation technologies, oxy-combustion technology uses pure oxygen.

In theory, oxy-combustion technology produces only carbon dioxide and water vapor (H2O) from burnt gas and does not generate nitrogen oxides (NOx), the main cause of fine dust.

In addition, because high concentrations of carbon dioxide can be easily recovered through water vapor condensation, it is advantageous for combination with carbon dioxide reduction techniques.

The power generation cycle using supercritical carbon dioxide as the working fluid has the advantage of significantly reducing the size of the system compared to existing steam power generation methods because the volume flow rate is small compared to the mass flow rate.

In addition, because of its strong incompressibility characteristics, the work required for compression is greatly reduced compared to existing steam power generation, thereby improving efficiency.

Referring to FIG. 1, the oxy-fuel combustion technology supplies carbon dioxide (or H2O) as a diluent gas to suppress the high adiabatic flame temperature of oxy-fuel combustion.

In particular, the critical point of carbon dioxide is 31°C, close to room temperature, and 7.37 MPa, and it exists in a supercritical state at temperatures and pressures higher than the critical point.

Supercritical carbon dioxide has a high density like a liquid, but has the characteristic of not having a free surface due to its low viscosity or high diffusion coefficient, which is close to that of a gas.

If the minimum operating pressure of the power generation system is maintained above the critical condition, the entire cycle can be configured above the critical pressure.

The conventional supercritical oxy-fuel power generation cycle mainly consists of a closed loop cycle to maintain high-pressure operating conditions. Due to this characteristic, if incomplete combustion products are generated within the cycle, they continue to accumulate and significantly deteriorate the performance of the gas turbine. causes

The main problematic incomplete combustion product is carbon monoxide. Carbon monoxide is produced in the combustion zone through a CO ₂ +H ↔ CO + OH reaction, and is rapidly cooled in the dilution zone and solidified at a temperature of about 900 K or less.

In this case, since combustion efficiency is reduced due to incomplete combustion and costs are incurred due to an additional process to remove stuck incomplete combustion products, a technology for minimizing incomplete combustion products inside the combustion chamber is required.

The purpose of the present invention is to provide a gas turbine combustion device that removes incomplete combustion gas by changing the ratio of dilution gas supplied to a plurality of combustion chambers according to the flow rate of exhaust gas.

A gas turbine combustion device according to one feature for realizing the object of the present invention described above is a combustion device that supplies exhaust gas generated through a combustion operation using oxygen and supercritical carbon dioxide to a turbine, and supplies oxygen and the turbine to the turbine. A combustion area in which flame and the exhaust gas are generated by burning the passing circulating gas; and a dilution area into which the exhaust gas flows to dilute incomplete combustion gas contained in the exhaust gas and cool the temperature of the exhaust gas to the operating temperature of the turbine,

The circulating gas is the supercritical carbon dioxide, the incomplete combustion gas is a gas that is fixed by a chemical reaction at a predetermined temperature, and the dilution zone is a gas that dilutes the incomplete combustion gas and flows in to prevent the chemical reaction. .

Additionally, the dilution area includes a plurality of dilution chambers into which the combustion gas flows, and the plurality of dilution chambers have different ratios of the dilution gas into them.

Additionally, the plurality of dilution chambers are divided into first to fifth dilution chambers, and the dilution gas is distributed and injected into the first to fifth dilution chambers in five stages.

In addition, the total amount of the dilution gas flowing into the dilution zone varies depending on the flow rate of the exhaust gas flowing into the dilution zone, and the rate at which the dilution gas flows into the first to fifth dilution chambers varies depending on the flow rate of the exhaust gas. They are different.

Additionally, the first to fifth dilution chambers have a plurality of coupling holes connected to the dilution gas supply line.

In addition, in the first to fifth dilution chambers, the plurality of coupling holes are formed to have different sizes depending on the flow rate of the exhaust gas.

Additionally, the first to fifth dilution chambers have different numbers of coupling holes depending on the flow rate of the exhaust gas.

And, the temperature of the dilution zone is 1500K to 1700K.

Additionally, the exhaust gas that has passed through the dilution zone is cooled to a temperature of 900K to 1000K and supplied to the turbine.

And, the pressure of the dilution area is 270 bar.

The incomplete combustion gas is carbon monoxide, and the dilution gas is a mixed gas of CH ₄ O ₂ and CO ₂ .

Here, the dilution gas is CH ₄ O ₂ based on 100 parts by weight. It accounts for 5 to 6 parts by weight, and the CO ₂ accounts for 94 to 95 parts by weight.

According to the gas turbine combustion device according to an embodiment of the present invention,

First, the removal of incomplete combustion gas can be maximized by changing the ratio of dilution gas supplied to the plurality of combustion chambers according to the flow rate of the exhaust gas.

Second, the oxidation reaction of carbon monoxide can be promoted by supplying a relatively low rate of dilution gas to the first to fourth dilution units and maintaining the temperature at 1500K to 1700K.

Third, a relatively high rate of dilution gas can be supplied to the fifth dilution unit to cool it to the turbine inlet temperature.

Fourth, the amount of incoming dilution gas can be adjusted by adjusting the size or number of the plurality of coupling holes.

1 is a conceptual diagram schematically showing a conventional gas turbine combustion device.
Figure 2 is a conceptual diagram schematically showing a gas turbine combustion device according to an embodiment of the present invention.
Figure 3 is a perspective view schematically showing the dilution area shown in Figure 2.
Figure 4 is a cross-sectional view showing the dilution gas distribution ratio according to the first embodiment.
Figure 5 is a cross-sectional view showing the dilution gas distribution ratio according to the second embodiment.
Figure 6 is a graph showing the mole fraction of carbon monoxide according to flow position.
Figure 7 is a graph showing temperature distribution according to flow location.

Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the attached drawings. At this time, note that in the attached drawings, identical components are indicated by identical symbols whenever possible. Additionally, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some components are exaggerated, omitted, or schematically shown in the accompanying drawings.

Figure 2 is a conceptual diagram schematically showing a gas turbine combustion device according to an embodiment of the present invention, and Figure 3 is a perspective view schematically showing the dilution area shown in Figure 2.

Figure 4 is a cross-sectional view showing the dilution gas distribution ratio according to the first embodiment, and Figure 5 is a cross-sectional view showing the dilution gas distribution ratio according to the second embodiment.

Referring to Figures 2 and 3, the present invention is a gas turbine combustion device 100 that supplies exhaust gas generated through a combustion operation using oxygen and supercritical carbon dioxide to the turbine 200.

The gas turbine combustion device 100 of the present invention is a can-type combustion chamber. The gas turbine combustion device 100 has a primary reaction zone 110 and a dilution zone 120. It is divided into

The combustion area 110 burns oxygen and the circulating gas that has passed through the turbine 200 to generate flame and exhaust gas, the fuel and oxidizer are partially premixed through a vortex, a portion of the diluted gas is injected together, and an appropriate gas is generated. Forms a stable flame through recirculation.

The dilution area 120 receives the exhaust gas generated in the combustion area 110, dilutes the incomplete combustion gas contained in the exhaust gas, and cools the temperature of the exhaust gas to the operating temperature of the turbine 200.

In addition, the dilution area 120 protects the gas turbine combustion device 100 from high-temperature flame and exhaust gas generated in the combustion area 110, and directs the exhaust gas to the turbine inlet through mixing of the bypassed dilution gas. The outlet temperature distribution of the gas turbine combustion device 100 is made uniform by cooling to the turbine inlet temperature (TIT).

Additionally, it reacts with various pollutants generated in the combustion area 110 to contribute to reducing pollutant emissions.

Here, the circulating gas is supercritical carbon dioxide, which passes through the turbine 200 and is supplied to the premixing section included in the combustion region 110 through the circulation line 210.

Incomplete combustion gas is a gas that is solidified by a chemical reaction at a predetermined temperature, and a representative example is carbon monoxide.

Additionally, dilution gas that dilutes the incomplete combustion gas is introduced into the dilution area 120 to prevent a chemical reaction of the incomplete combustion gas.

Here, the pressure of the dilution area 120 is 270 bar, the dilution gas is a mixed gas of CH ₄ O ₂ and CO ₂ , and the dilution gas is CH ₄ O ₂ per 100 parts by weight. It accounts for 5 to 6 parts by weight, and CO ₂ accounts for 94 to 95 parts by weight.

Additionally, the temperature of the dilution area 120 is maintained at 1500K to 1700K.

The dilution area 120 includes a plurality of dilution chambers 121, 122, 123, 124, and 125 into which exhaust gas flows, and the plurality of dilution chambers 121, 122, 123, 124, and 125 are used to determine the ratio of the dilution gas. This comes in differently.

The plurality of dilution chambers (121, 122, 123, 124, 125) are divided into first to fifth dilution chambers (121, 122, 123, 124, 125), and first to fifth dilution chambers (121, 122, 123, 124, and 125), dilution gas is distributed and injected in five stages.

The total amount of dilution gas flowing into the dilution area 120 varies depending on the flow rate of the exhaust gas flowing into the dilution area 120, and is divided into the first to fifth dilution chambers 121, 122, 123, 124, 125), the inflow rates are different.

Additionally, a plurality of coupling holes 126 coupled to a dilution gas supply line (not shown) are formed in the first to fifth dilution chambers 121, 122, 123, 124, and 125.

Here, the plurality of coupling holes 126 formed in the first to fifth dilution chambers 121, 122, 123, 124, and 125 have different sizes depending on the flow rate of the exhaust gas flowing into the dilution area 120.

In addition, the plurality of coupling holes 126 formed in the first to fifth dilution chambers 121, 122, 123, 124, and 125 are formed in different numbers depending on the flow rate of the exhaust gas flowing into the dilution area 120.

With reference to FIGS. 4 and 5 , the dilution gas distribution ratio according to the exhaust gas inflow will be described.

The dilution gas distribution ratio according to the first embodiment will be described with reference to FIG. 4.

The first embodiment is the ratio of dilution gas distributed to the first to fifth dilution chambers (121, 122, 123, 124, and 125) when the inflow amount of exhaust gas is 0.792 kg/s.

In this case, for 100% of the amount of dilution gas flowing into the dilution area 120, 30% flows into the first dilution part 121, 10% flows into the second dilution part 122, and 30% flows into the third dilution part 120. 5% is distributed to each of 123 and the fourth dilution unit 124, and 50% is distributed to the fifth dilution unit 125.

In the case of the first embodiment, the incoming exhaust gas is cooled to 1500K to 1700K, which is the temperature at which the oxidation reaction of carbon monoxide is active, and then first to fourth dilution parts 121, 122, and 123 so that the incoming exhaust gas can be maximally exposed to a temperature of 1500K to 1700K. , 124), minimize the injection of diluting gas.

Then, the remaining dilution gas is injected from the fifth dilution unit 125 and cooled to reach the turbine inlet temperature.

The dilution gas distribution ratio according to the second embodiment will be described with reference to FIG. 5.

The first embodiment is the ratio of dilution gas distributed to the first to fifth dilution chambers (121, 122, 123, 124, and 125) when the inflow amount of exhaust gas is 0.410 kg/s.

In this case, for 100% of the total amount of dilution gas flowing into the dilution area 120, 10% flows into the first dilution part 121, 10% also flows into the second dilution part 122, and 10% flows into the third dilution part. 5% is distributed and introduced into the unit 123 and the fourth dilution unit 124, and 70% is distributed into the fifth dilution unit 125.

In the case of the second embodiment, as in the first embodiment, the injection of dilution gas into the first to fourth dilution parts 121, 122, 123, and 124 is minimized to maximize exposure to the exhaust gas at a temperature of 1500K to 1700K. Then, the remaining dilution gas is injected from the fifth dilution unit 125 to cool the exhaust gas to reach the turbine inlet temperature.

Figure 6 is a graph showing the mole fraction of carbon monoxide according to the flow location, and Figure 7 is a graph showing the temperature distribution according to the flow location.

6 and 7, the dilution reaction of incomplete combustion gas according to the operation of the gas turbine combustion device 100 of the present invention will be described.

The results in Figures 6 and 7 are the plug flow reactor-based chemical reactor network model and detailed chemistry simulation results, and the detailed chemical reaction mechanism used was the Reduced ITV mechanism.

When the dilution gas is injected at once, the carbon monoxide reaches an equilibrium state and is discharged to the turbine in a fixed state without further reacting.

This can continuously accumulate due to the characteristics of a closed-circuit system, resulting in a significant decrease in system efficiency.

By injecting a small amount of dilution gas from the first to fourth dilution chambers 121, 122, 123, and 124 of the dilution area 120, a large amount of carbon monoxide is reacted quickly by maintaining a temperature of about 1600 K, and the fifth dilution chamber 125 ), it can be reduced by more than 80% compared to before by oxidizing a small amount of remaining carbon monoxide through gradual cooling by injecting a large amount of dilution gas.

As shown in Figures 6 and 7, in order to minimize carbon monoxide emissions, it is important to distribute and inject dilution gas at an appropriate ratio into the first to fifth dilution chambers (121, 122, 123, 124, and 125). You can.

Therefore, the gas turbine combustion device 100 of the present invention can maximize the carbon monoxide oxidation reaction by maintaining the optimal reaction temperature for the carbon monoxide oxidation reaction inside the dilution region 120.

Although the description has been made with reference to the above examples, those skilled in the art will understand that various modifications and changes can be made to the present invention without departing from the spirit and scope of the present invention as set forth in the claims below. You will be able to.

110...combustion area 120...dilution area
121...First dilution chamber 122...Second dilution chamber
123...3rd dilution room 124...4th dilution room
125...Fifth dilution chamber 126...Combining hole
200...turbine 210...circulation line

Claims (12)

In a combustion device that supplies exhaust gas generated through a combustion operation using oxygen and supercritical carbon dioxide to a turbine,
A combustion area in which flame and the exhaust gas are generated by burning oxygen and the circulating gas that has passed through the turbine; and
A dilution area where the exhaust gas flows in to dilute incomplete combustion gas contained in the exhaust gas and cool the temperature of the exhaust gas to the operating temperature of the turbine.
Including,
The circulating gas is the supercritical carbon dioxide,
The incomplete combustion gas is a gas that is fixed by a chemical reaction at a predetermined temperature,
The dilution area includes a plurality of dilution chambers into which a dilution gas that dilutes the incomplete combustion gas flows in to prevent the chemical reaction, and into which the exhaust gas flows, and the plurality of dilution chambers have a ratio of the inflow dilution gas of Other, gas turbine combustion devices. delete According to paragraph 1,
The plurality of dilution chambers are divided into first to fifth dilution chambers,
A gas turbine combustion device in which the dilution gas is distributed and injected into the first to fifth dilution chambers in five stages. According to paragraph 3,
The dilution gas is
The total amount flowing into the dilution zone varies depending on the flow rate of the exhaust gas flowing into the dilution zone,
A gas turbine combustion device in which the rate of inflow into the first to fifth dilution chambers is different depending on the flow rate of the exhaust gas. According to paragraph 4,
The first to fifth dilution chambers are
A gas turbine combustion device in which a plurality of coupling holes coupled to a dilution gas supply line are formed. According to clause 5,
The first to fifth dilution chambers are
A gas turbine combustion device in which the plurality of coupling holes are formed differently in size depending on the flow rate of the exhaust gas. According to clause 5,
The first to fifth dilution chambers are
A gas turbine combustion device in which the number of the plurality of coupling holes is formed differently depending on the flow rate of the exhaust gas. According to paragraph 1,
The temperature of the dilution zone is 1500K to 1700K, a gas turbine combustion device. According to paragraph 1,
The exhaust gas that has passed through the dilution zone is cooled to a temperature of 900K to 1000K and supplied to the turbine. According to paragraph 1,
A gas turbine combustion device where the pressure of the dilution area is 270 bar. According to paragraph 1,
The incomplete combustion gas is carbon monoxide,
The dilution gas is a gas turbine combustion device in which CH4O2 and CO2 are mixed. According to clause 11,
The dilution gas is,
A gas turbine combustion device, in which CH4O2 accounts for 5 to 6 parts by weight, and CO2 accounts for 94 to 95 parts by weight, based on 100 parts by weight.

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