KR20220135554A - Combined power plant and operating method of the same - Google Patents

Abstract

A combined power generation system according to an aspect of the present invention comprises: a gas turbine which generates a rotational force by burning fuel; a waste heat recovery boiler which heats feedwater using combustion gas discharged from the gas turbine and has a high pressure part, a medium pressure part, and a low pressure part having different pressure levels; a fuel preheater which heats the fuel supplied to the gas turbine and has a primary heating part and a secondary heating part; a high-pressure water supply pipe connected to the high pressure part to supply high pressure feedwater to the secondary heating part; a feedwater delivery pipe for connecting the secondary heating part and the primary heating part to supply the feedwater discharged from the secondary heating part to the primary heating part; a feedwater control pipe connected to the medium pressure part to supply medium pressure feedwater to the feedwater delivery pipe; and an intermediate control valve installed between the primary heating part and the secondary heating part to control the flow rate of the high pressure feedwater flowing into the secondary heating part and controlling the flow rate of the medium pressure feedwater according to the flow rate of the high pressure feedwater. The present invention can prevent the fuel from overheating.

Description

Combined power generation system and method of driving combined power generation system

The present invention relates to a combined power generation system and a method of driving the combined power generation system. More particularly, the present invention relates to a combined power generation system having a gas turbine and a fuel preheater and a method of driving the combined power generation system.

The combined cycle power generation system is a power generation system that combines a gas turbine and a steam turbine with high efficiency to guide high-temperature exhaust gas from the gas turbine to a heat recovery boiler (HRSG) and generate steam by thermal energy retained in the exhaust gas. This steam enables power generation by the steam turbine and can be combined with the power generated by the gas turbine to improve thermal efficiency equivalent to the thermal energy retained in the exhaust gas when compared to independent power production by the gas turbine. .

A gas turbine is a power engine that mixes and burns compressed air and fuel compressed in a compressor, and rotates the turbine with high-temperature gas generated by combustion. Gas turbines are used to power generators, aircraft, ships, trains, and the like.

In order to improve the efficiency of the gas turbine, it is necessary to preheat the fuel flowing into the gas turbine. As the fuel is preheated to a high temperature, the temperature of the gas turbine increases. However, if the fuel is overheated, the fuel may be carbonized due to thermal decomposition during the preheating process.

Based on the technical background as described above, the present invention provides a combined cycle power generation system capable of efficiently preheating fuel supplied to a gas turbine and a method of driving the combined cycle power generation system.

The combined cycle power generation system according to an aspect of the present invention includes a gas turbine generating rotational force by burning fuel, heating feedwater using combustion gas discharged from the gas turbine, and having a high-pressure part, a medium-pressure part, and a low-pressure part having different pressure levels from each other A heat recovery boiler, a fuel preheater that heats the fuel supplied to the gas turbine and has a primary heating unit and a secondary heating unit, a high-pressure water supply pipe connected to the high-pressure unit to supply high-pressure water to the secondary heating unit, and the secondary heating A water supply transmission pipe connecting the unit and the primary heating unit to supply the water discharged from the secondary heating unit to the primary heating unit, a water supply control pipe connected to the intermediate pressure unit and supplying medium pressure water to the water supply pipe, and an intermediate control valve installed between the primary heating unit and the secondary heating unit to control the flow rate of the high-pressure water supply flowing into the secondary heating unit, and controlling the flow rate of the medium-pressure water supply according to the flow rate of the high-pressure water supply. can

The intermediate pressure unit according to an aspect of the present invention includes a medium pressure pump that pressurizes and moves the water supply, and a medium pressure economizer that receives water supply from the medium pressure pump and heats the water supply, wherein the water supply control pipe includes the medium pressure pump and the medium pressure economizer. It may be connected to receive water supply from the medium pressure pump.

The high-pressure water supply pipe according to an aspect of the present invention may supply liquid water supply to the secondary heating unit.

The high-pressure unit according to an aspect of the present invention comprises a high-pressure economizer for heating feedwater, a high-pressure drum for storing the feedwater heated in the high-pressure economizer, and a high-pressure evaporator for heating the water in the high-pressure drum and converting it into steam, The high-pressure water supply pipe may be connected between the high-pressure economizer and the high-pressure drum to receive water heated by the high-pressure economizer.

The intermediate control valve according to an aspect of the present invention may be located between the second heating unit and a connection part to which the water supply control pipe and the water supply transmission pipe are connected.

The combined power generation system according to an aspect of the present invention is installed in a feed water recovery pipe for delivering the feed water discharged from the primary heating unit to a heat recovery boiler and the feed water recovery pipe to control the flow rate of feed water discharged from the primary heating unit It may further include a downstream control valve.

The surplus high-pressure water discharged from the secondary heating unit by the downstream control valve according to an aspect of the present invention may be supplied to the medium-pressure economizer through the water supply control pipe.

The combined cycle power generation system according to an aspect of the present invention connects the upstream of the primary heating unit and the downstream of the secondary heating unit, bypassing the primary heating unit and the secondary heating unit, and supplying fuel to the downstream of the secondary heating unit. It may further include a bypass tube for moving.

The combined cycle power generation system according to an aspect of the present invention further includes a bypass pipe connecting the upstream of the primary heating unit and the upstream of the secondary heating unit to bypass the primary heating unit and move fuel to the secondary heating unit. can do.

A fuel control valve for controlling the flow rate of fuel moving through the bypass pipe may be installed in the bypass pipe according to an aspect of the present invention.

The primary heating unit and the secondary heating unit according to an aspect of the present invention may have the same capacity.

In the water supply control pipe according to an aspect of the present invention, an intermediate pressure control valve for controlling the flow rate of water supplied from the water supply control pipe to the water supply transmission pipe may be installed.

A gas turbine, a steam turbine, a heat recovery boiler, and a fuel preheater having a primary heating part and a secondary heating part for preheating fuel according to an aspect of the present invention, wherein the heat recovery boiler includes a low pressure part, a medium pressure part, and a high pressure part The driving method of the combined cycle power generation system including a fuel preheating step, a fuel temperature determination step of measuring the temperature of the fuel discharged from the primary heating unit and the temperature of the fuel discharged from the secondary heating unit and comparing it with a reference temperature, and the fuel temperature being discharged from the primary heating unit and a valve control step of controlling the temperature of the fuel by adjusting a downstream control valve for controlling the flow rate of feedwater and an intermediate control valve for controlling movement of feedwater between the primary heating unit and the secondary heating unit.

In the fuel preheating step according to an aspect of the present invention, the water supplied through the water supply control pipe connected between the medium pressure pump and the medium pressure economizer of the medium pressure unit is mixed with the water discharged from the secondary heating unit to the primary heating unit. can supply

In the fuel preheating step according to an aspect of the present invention, water may be supplied to the secondary heating unit through a high pressure water supply pipe connected between the high pressure economizer and the high pressure drum of the high pressure unit.

In the valve control step according to an aspect of the present invention, when the temperature of the fuel discharged from the primary heating unit is lower than a preset first reference temperature, the opening degree of the downstream control valve is increased, and in the primary heating unit When the temperature of the discharged fuel is higher than the first reference temperature, the degree of opening of the downstream control valve is reduced, and when the temperature of the fuel discharged from the secondary heating unit is lower than the preset second reference temperature, the intermediate control valve The opening degree may be increased, and when the temperature of the fuel discharged from the secondary heating unit is higher than the second reference temperature, the opening degree of the intermediate control valve may be decreased.

In the valve control step according to an aspect of the present invention, a fuel control valve installed in a bypass pipe for supplying fuel to a downstream side of the secondary heating unit by bypassing the primary heating unit and the secondary heating unit is adjusted to control the temperature of the fuel. However, when the temperature of the fuel discharged from the secondary heating unit is lower than the preset second reference temperature, the opening degree of the fuel control valve is reduced, and when the fuel control valve is closed, the intermediate control valve is opened degree can be increased.

In the valve control step according to an aspect of the present invention, when the temperature of the fuel discharged from the secondary heating unit is higher than the second reference temperature, the opening degree of the fuel control valve is increased, and the fuel control valve is completely opened. If necessary, the opening degree of the intermediate control valve can be reduced.

In the valve control step according to an aspect of the present invention, the temperature of the fuel is adjusted by adjusting the intermediate pressure control valve for controlling the flow rate of the water supplied from the intermediate pressure unit, but the temperature of the fuel discharged from the primary heating unit is When it is lower than the set first reference temperature, the opening degree of the intermediate pressure control valve is reduced and the opening degree of the downstream control valve is increased, and when the temperature of the fuel discharged from the primary heating unit is higher than the first reference temperature, It is possible to increase the opening degree of the intermediate pressure control valve and decrease the opening degree of the downstream control valve.

In the valve control step according to an aspect of the present invention, the temperature of the fuel is controlled by adjusting a fuel control valve installed in a bypass pipe that bypasses the primary heating unit and supplies fuel to an upstream side of the secondary heating unit, When the temperature of the fuel discharged from the car heating unit is lower than the preset second reference temperature, the opening degree of the fuel control valve is decreased, and when the fuel control valve is closed, the opening degree of the intermediate control valve is increased, and the When the temperature of the fuel discharged from the secondary heating unit is higher than the second reference temperature, the opening degree of the fuel control valve may be increased, and if the fuel control valve is fully opened, the opening degree of the intermediate control valve may be decreased. .

As described above, in the combined cycle power generation system according to an aspect of the present invention, sufficient heat can be supplied to the fuel by supplying water from the high-pressure part to the secondary heating part, and supplying the water discharged from the secondary heating part to the primary heating part. In addition, it is possible to prevent the fuel from overheating by controlling the temperature of the water supply by using the water supply of the intermediate pressure part.

1 is a configuration diagram illustrating a combined power generation system according to a first embodiment of the present invention.
2 is a block diagram illustrating a fuel preheater and a heat recovery boiler according to the first embodiment of the present invention.
3 is a configuration diagram illustrating a fuel preheater according to a first embodiment of the present invention.
4 is a flowchart illustrating a method of driving the combined cycle power generation system according to the first embodiment of the present invention.
5 is a configuration diagram illustrating a fuel preheater according to a second embodiment of the present invention.
6 is a configuration diagram illustrating a fuel preheater according to a third embodiment of the present invention.
7 is a configuration diagram illustrating a fuel preheater according to a fourth embodiment of the present invention.

Since the present invention can apply various transformations and can have various embodiments, specific embodiments are illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, and should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention.

The terms used in the present invention are only used to describe specific embodiments, and are not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present invention, terms such as 'comprise' or 'have' are intended to designate that the features, numbers, steps, operations, components, parts, or combinations thereof described in the specification exist, and one or more other features It is to be understood that this does not preclude the possibility of the presence or addition of numbers, steps, operations, components, parts, or combinations thereof.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. At this time, it should be noted that in the accompanying drawings, the same components are denoted by the same reference numerals as much as possible. In addition, 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 illustrated in the accompanying drawings.

Hereinafter, a gas turbine according to a first embodiment of the present invention will be described.

1 is a configuration diagram showing a combined cycle power generation system according to a first embodiment of the present invention, FIG. 2 is a configuration diagram showing a fuel preheater and a heat recovery boiler according to the first embodiment of the present invention, and FIG. 3 is A configuration diagram illustrating a fuel preheater according to a first embodiment of the present invention.

1 to 3 , the combined cycle power generation system 100 according to the first embodiment includes a plurality of turbines to generate electric power. The combined cycle power generation system 100 includes a gas turbine 110 , a generator 130 , a heat recovery boiler 140 , a steam turbine 120 , a fuel preheater 150 , a high-pressure water supply pipe 153 , a water supply pipe 155 , It may include a water supply control pipe 154 , a downstream control valve 161 , and an intermediate control valve 162 .

The gas turbine 110 according to this embodiment sucks atmospheric air, compresses it to a high pressure, burns fuel in a static pressure environment to release thermal energy, expands this high temperature combustion gas to convert it into kinetic energy, and then converts the residual energy into kinetic energy. Exhaust gases containing

The gas turbine 110 may include a compressor 112 , a combustor 115 , and a main turbine 113 . The compressor 112 of the gas turbine 110 may suck air from the outside and compress it. The compressor 112 may supply compressed air compressed by the compressor blades to the combustor 115 , and may also supply cooling air to a high temperature region requiring cooling in the gas turbine 110 . At this time, since the sucked air undergoes an adiabatic compression process in the compressor 112 , the pressure and temperature of the air passing through the compressor 112 are increased.

The compressor 112 is designed as centrifugal compressors or axial compressors. A centrifugal compressor is applied to a small gas turbine, whereas a multi-stage axial compressor is applied to the same large gas turbine 110 .

On the other hand, the combustor 115 may mix the compressed air supplied from the outlet of the compressor 112 with the fuel and perform isostatic combustion to produce combustion gas of high energy.

The high-temperature, high-pressure combustion gas produced in the combustor 115 is supplied to the main turbine 113 . In the main turbine 113, the thermal energy of the combustion gas is converted into mechanical energy in which the rotating shaft rotates by colliding with a plurality of blades radially disposed on the rotating shaft of the main turbine 113 while the combustion gas expands adiabatically, and by giving a reaction force. A part of the mechanical energy obtained from the main turbine 113 is supplied as energy required to compress the air in the compressor 112 , and the remainder is utilized as effective energy such as driving the generator 130 to generate electric power.

The combustion gas discharged from the main turbine 113 is cooled through the heat recovery boiler 140 and then purified and discharged to the outside. The heat recovery boiler 140 not only cools the combustion gas, but also generates high-temperature and high-pressure steam using the heat of the combustion gas and delivers it to the steam turbine 120 .

The steam generated in the heat recovery boiler 140 is transmitted to the steam turbine 120 through the steam supply line 181 , and the feed water cooled in the steam turbine 120 is transferred to the heat recovery boiler through the turbine feed water recovery line 182 . (140).

The steam turbine 120 rotates blades using the steam generated by the heat recovery boiler 140 and transfers rotational energy to the generator 130 . The steam turbine 120 supplies the cooled steam back to the heat recovery boiler 140 .

In the first embodiment, the main turbine 113 and the steam turbine 120 are exemplified as being connected to one generator 130, but the present invention is not limited thereto, and the steam turbine 120 and the main turbine 113 are not limited thereto. ) can be placed in parallel and connected to different generators.

The turbine feedwater recovery line 182 includes a condenser 121 for condensing steam, a condensate storage tank 122 for storing condensed feedwater, and a condensate pump 123 for supplying the condensed water stored in the condensed water storage tank 122 to the heat recovery boiler. can be installed.

The steam moving inside the heat recovery boiler 140 may have a pressure of two or three stages, and accordingly, the feed water is pressurized to two or three or more pressure levels. In this embodiment, the heat recovery boiler 140 is exemplified as having three stages of pressure.

The heat recovery boiler 140 may include a low-pressure part G1 having a relatively low pressure, a medium-pressure part G2 having a medium pressure, and a high-pressure part G3 having a relatively high pressure. The high-pressure part (G3) is disposed adjacent to the inlet side where the combustion gas is introduced and is heated by the high-temperature combustion gas, and the low-pressure part (G1) is disposed adjacent to the exit side where the combustion gas is discharged and is heated by the low-temperature combustion gas. can be

Inside the heat recovery boiler 140, a condensate preheater 141, a low pressure evaporator 142, a medium pressure economizer 143, a medium pressure evaporator 144, a high pressure economizer 145, and a high pressure evaporator 146 are installed. In addition, each superheater (not shown) may be additionally installed on the upstream side of the evaporators. The combustion gas discharged from the heat recovery boiler 140 may be discharged through the stack.

The low-pressure unit G1 includes a condensate preheater 141 , a low-pressure evaporator 142 , and a low-pressure drum 147 . The condensate stored in the condensate storage tank 122 is transferred to the condensate preheater 141 by the condensate pump 123 , and the condensate preheater 141 heats the condensate through heat exchange with combustion gas. The feed water heated in the condensate preheater 141 is transferred to the deaerator 175 to remove gas from the condensate.

Feed water is supplied from the deaerator 175 to the low pressure drum 147, and the low pressure evaporator 142 is connected to the low pressure drum 147 to heat the feed water stored in the low pressure drum 147 and convert it into steam. 147), after separation of the brackish water, it can be supplied to the superheater.

Meanwhile, the intermediate pressure unit G2 includes a medium pressure economizer 143 , a medium pressure evaporator 144 , and a medium pressure drum 148 . The feed water of the deaerator 175 is supplied to the medium pressure economizer 143 by the medium pressure pump 172, and the medium pressure economizer 143 heats the water supply through heat exchange with combustion gas. The feed water heated by the medium pressure economizer 143 is supplied to the medium pressure drum 148, and the medium pressure evaporator 144 is connected to the medium pressure drum 148 to heat the feed water stored in the medium pressure drum 148 and convert it into steam. After the brackish water is separated in the medium pressure drum 148, it may be supplied to the superheater.

The high-pressure part G3 includes a high-pressure economizer 145 , a high-pressure evaporator 146 , and a high-pressure drum 149 . The feed water of the deaerator 175 is supplied to the high pressure economizer 145 by the high pressure pump 173, and the high pressure economizer 145 heats the feed water through heat exchange with combustion gas. The feed water heated by the high pressure economizer 145 is supplied to the high pressure drum 149, and the high pressure evaporator 146 is connected to the high pressure drum 149 to heat the feed water stored in the high pressure drum 149 and convert it into steam. After separating the brackish water from the high-pressure drum 149, it may be supplied to the superheater.

The steam stored in the low pressure drum 147 , the medium pressure drum 148 , and the high pressure drum 149 may be supplied to the respective low pressure, medium pressure, and high pressure steam turbines after being heated in the superheater.

The high-pressure water supply pipe 153 connects the high-pressure part G3 and the fuel preheater 150 to supply high-temperature, high-pressure water to the fuel preheater 150 . A high-pressure valve 176 for controlling the flow rate of water supplied to the high-pressure water supply pipe 153 may be installed downstream of the high-pressure water supply pipe 153 . Meanwhile, the water supply control pipe 154 connects the intermediate pressure part G2 and the fuel preheater 150 to supply the intermediate pressure water supply to the fuel preheater 150 .

The fuel preheater 150 receives fuel from the fuel supply unit 117 through the fuel supply pipe 157 , heats it, and then supplies it to the combustor 115 . Here, the fuel may be a gas, but the present invention is not limited thereto.

The fuel preheater 150 includes a primary heating unit 151 for primarily heating fuel and a secondary heating unit 152 for secondary heating of the heated fuel. The primary heating unit 151 receives fuel from the fuel supply unit 117 and heats the fuel through heat exchange with relatively low temperature feed water, and then transfers it to the secondary heating unit 152 , and the secondary heating unit 152 . ) heats the fuel delivered from the primary heating unit 151 to a high temperature through heat exchange with high-pressure water.

The high-pressure water supply pipe 153 is connected to the secondary heating unit 152 to supply high-temperature water to the secondary heating unit 152 . The high-pressure water supply pipe 153 may be connected between the high-pressure economizer 145 and the high-pressure drum 149 to supply water heated by the high-pressure economizer 145 to the secondary heating unit 152 . Here, the high-pressure water supply is made of a liquid rather than a vapor, and the phase of the water supply does not change in the fuel preheater 150 and maintains a liquid state. When the phase of water supply is changed in the fuel preheater 150 , vibration may occur due to a sudden change in pressure.

The water supply pipe 155 transmits the water cooled by heat exchange with fuel in the secondary heating unit 152 to the primary heating unit 151 . Meanwhile, a water supply control pipe 154 is connected to the water supply transmission pipe 155 to supply medium pressure water to the water supply transmission pipe 155 .

The water supply control pipe 154 is connected to the downstream side of the intermediate pressure pump 172 to supply the water pressurized by the intermediate pressure pump 172 to the water supply transmission pipe 155 . In addition, since the water supply control pipe 154 is connected between the medium pressure pump 172 and the medium pressure economizer 143 , the unheated water supply from the medium pressure unit G2 is supplied to the supply water supplied to the primary heating unit 151 . The temperature can be easily adjusted to prevent the fuel from overheating.

In addition, since the water supply control pipe 154 is connected to the downstream side of the medium pressure pump 172 , it can be operated independently without affecting the medium pressure economizer 143 . In addition, since the water supply that is not heated in the intermediate pressure unit G2 is supplied to the primary heating unit 151, the water supply temperature is low, so that the possibility of steam-induced vibration is reduced. In addition, since the feed water pressurized at a high pressure is supplied from the intermediate pressure pump 172 , the possibility that the fuel gas leaks to the water feed side is lowered due to the high feed water pressure.

When the pipe supplying water supply is connected to the downstream side of the medium pressure economizer 143, it is difficult to control the temperature of the water supply supplied to the primary heating unit 151, the temperature of the water supply is high, and vibration occurs, and the pressure of the water supply is low. Low problems may arise.

Meanwhile, the capacity of the primary heating unit 151 and the secondary heating unit 152 may be the same, and accordingly, water may be supplied to the water supply transmission pipe through the water supply control pipe 154 only when necessary. The feed water discharged from the secondary heating unit 152 and the water supplied from the water supply control pipe 154 are mixed and supplied to the primary heating unit 151 .

In the connection part P1 where the water supply control pipe 154 and the water supply transmission pipe 155 are connected, the upstream side has a pressure higher than that of the water supply control pipe 154, and the downstream side has a lower pressure than the water supply control pipe 154 or water supply control. It may have a pressure similar to that of the tube 154 .

If the downstream pressure of the water supply pipe 155 in the connection part P1 is the same as the pressure of the water supply control pipe 154, the water supply cannot move from the water supply control pipe 154 to the water supply pipe 155, and the water supply pipe When the downstream pressure of 155 is higher than the pressure of the water supply control pipe 154 , the water supply moving through the water supply transmission pipe 155 may be introduced into the water supply control pipe 154 . As such, the water supply control pipe 154 is connected to the water supply transmission pipe 155 to control the temperature of the water supply and the pressure of the water supply.

On the other hand, the water supply recovery pipe 158 is connected to the primary heating unit 151 , and the water supply recovery pipe 158 is connected to the downstream side of the condensate pump 123 to heat the fuel in the primary heating unit 151 . The discharged feedwater is delivered to the heat recovery boiler 140 .

A first thermometer T1 for measuring the temperature of the fuel discharged from the primary heating unit 151 is installed in the fuel supply pipe 157 between the primary heating unit 151 and the secondary heating unit 152, 2 A second thermometer T2 for measuring the temperature of fuel discharged from the secondary heating unit 152 is installed in the fuel supply pipe 157 on the downstream side of the car heating unit 152 .

In addition, a downstream control valve 161 for controlling the flow rate of the feed water discharged from the primary heating unit 151 is installed in the water supply return pipe 158 . The downstream control valve 161 regulates the flow rate of water flowing in from the water supply control pipe 154 and the water supply moving through the water supply transmission pipe 155 . When the opening degree of the downstream control valve 161 decreases, the surplus high-pressure water discharged from the secondary heating unit 152 may be supplied to the medium-pressure economizer 143 through the water supply control pipe 154 .

An intermediate control valve 162 is installed in the water supply transmission pipe 155 , and the intermediate control valve 162 adjusts the flow rate of the high-pressure water supply flowing into the secondary heating unit 152 . The intermediate control valve 162 is positioned between the connection part P1 to which the water supply control pipe 154 and the water supply transmission pipe 155 are connected and the secondary heating part 152 .

Accordingly, if the opening degree of the downstream control valve 161 is decreased and the opening degree of the intermediate control valve 162 is maintained in an increased state, the amount of water supplied through the secondary heating unit 152 increases, and the primary heating The flow rate of feed water moving through the portion 151 may be reduced. When the opening degree of the downstream control valve 161 decreases, if the high-pressure water supply does not move through the water supply control pipe 154, the flow is accumulated and the flow rate of the water supply moving through the secondary heating unit 152 is also reduced. A problem arises.

On the other hand, when the opening degree of the downstream control valve 161 is increased, the medium pressure water supplied through the water supply control pipe 154 together with the high pressure water discharged from the secondary heating unit 152 is 1 through the water supply transmission pipe 155 . It may be supplied to the car heating unit.

In addition, when the opening degree of the intermediate control valve 162 decreases, the flow rate of the water supply discharged from the secondary heating unit 152 decreases, so the flow rate of the medium pressure water supply flowing from the water supply control pipe 154 to the water supply transmission pipe 155 is reduced. this will increase When the opening degree of the intermediate control valve 162 is increased, the flow rate of the feed water discharged from the secondary heating unit 152 is increased, so that the flow rate of the medium pressure water flowing from the water supply control pipe 154 to the water delivery pipe 155 is reduced. will do

As described above, according to the first embodiment, the feed water heated in the high-pressure economizer 145 is transferred to the secondary heating unit through the high-pressure water supply pipe 153 so that the fuel can be heated to a high temperature as well as the water supply control pipe 154 ) is installed between the medium pressure pump 172 and the medium pressure economizer 143 to easily control the temperature of the feed water flowing into the primary heating unit 151 .

Hereinafter, a method of driving the combined cycle power generation system according to the first embodiment of the present invention will be described. 4 is a flowchart illustrating a method of driving the combined cycle power generation system according to the first embodiment of the present invention.

3 and 4, the driving method of the combined cycle power generation system according to the present embodiment may include a fuel preheating step (S101), a fuel temperature determining step (S102), and a valve control step (S103).

In the fuel preheating step ( S101 ), the water supplied from the secondary heating unit 152 and the water supplied from the intermediate pressure unit G2 are mixed and supplied to the primary heating unit 151 , and the water heated by the high pressure unit G3 is mixed. is supplied to the secondary heating unit 152 .

In the fuel preheating step S101 , water is supplied to the secondary heating unit 152 through the high-pressure water supply pipe 153 connected between the high-pressure economizer 145 and the high-pressure drum 149 in the high-pressure unit G3 . In addition, in the fuel preheating step (S101), the supply water discharged from the secondary heating unit 152 is supplied to the primary heating unit 151 through the water supply transmission pipe 155, and the medium pressure pump 172 in the medium pressure unit G2. ) and the water supply control pipe 154 connected between the medium pressure economizer 143 is connected to the water supply transmission pipe 155 to supply water to the water supply transmission pipe 155 .

In the fuel temperature determination step (S102), the temperature of the fuel discharged from the primary heating unit 151 and the temperature of the fuel discharged from the secondary heating unit 152 are measured and compared with a reference temperature. In the fuel temperature determination step (S102), the temperature of the fuel is measured using the first thermometer T1 installed between the primary heating unit 151 and the secondary heating unit 152 and compared with the first reference temperature, 2 After measuring the temperature of the fuel using the second thermometer T2 installed on the downstream side of the car heating unit 152, it is compared with the second reference temperature. Here, the preset first reference temperature that is the comparison target of the temperature measured by the first thermometer is lower than the preset second reference temperature that is the comparison target of the temperature measured by the second thermometer. The first reference temperature and the second reference temperature may be set in various ranges according to the capacity of the gas turbine, the type of fuel, and the like.

In the valve control step (S103), a downstream control valve 161 for controlling the flow rate of feed water discharged from the primary heating unit 151 and movement of the water supply between the primary heating unit 151 and the secondary heating unit 152 The temperature of the fuel is adjusted by adjusting the intermediate control valve 162 that controls the .

In the valve control step ( S103 ), when the temperature of the fuel discharged from the primary heating unit 151 is lower than the first reference temperature, the opening degree of the downstream control valve 161 is increased and discharged from the primary heating unit 151 . When the temperature of the used fuel is higher than the first reference temperature, the opening degree of the downstream control valve 161 is reduced.

In addition, in the valve control step ( S103 ), when the temperature of the fuel discharged from the secondary heating unit 152 is lower than the second reference temperature, the opening degree of the intermediate control valve 162 is increased, and the secondary heating unit 152 . If the temperature of the fuel discharged from the is higher than the second reference temperature, the opening degree of the intermediate control valve 162 is reduced.

As described above, according to the first embodiment, it is possible to efficiently preheat the fuel while preventing the fuel from being overheated by including the valve control step S103.

Hereinafter, a combined power generation system according to a second embodiment of the present invention will be described. 5 is a configuration diagram illustrating a fuel preheater according to a second embodiment of the present invention.

5, since the combined cycle power generation system according to the second embodiment has the same structure as the combined cycle power generation system according to the first embodiment except for the bypass pipe 156, the A duplicate description will be omitted.

A bypass pipe 156 for supplying fuel to the downstream side of the secondary heating unit 152 by bypassing the primary heating unit 151 and the secondary heating unit 152 is connected to the fuel supply pipe 157 . In addition, a fuel control valve 163 for controlling the flow rate of fuel moving through the bypass pipe 156 is installed in the bypass pipe 156 .

The fuel control valve 163 controls the flow rate of the fuel passing through the primary heating unit 151 and the secondary heating unit 152 , thereby more easily controlling the heating temperature of the fuel.

Hereinafter, a method of driving a combined cycle power generation system according to a second embodiment of the present invention will be described.

Since the driving method of the combined cycle power generation system according to the second embodiment is the same as the driving method of the combined cycle power generation system according to the second embodiment, except for the valve control step, a redundant description of the same configuration will be omitted.

The valve control step includes a downstream control valve 161 for controlling the quantity of water discharged from the primary heating unit 151 and controlling the movement of water supply between the primary heating unit 151 and the secondary heating unit 152 . A fuel control valve installed in the bypass pipe 156 for supplying fuel to the downstream side of the secondary heating unit 152 without passing through the intermediate control valve 162 , the primary heating unit 151 , and the secondary heating unit 152 . (163) is adjusted to control the temperature of the fuel.

In the valve control step, when the temperature of the fuel discharged from the primary heating unit 151 is lower than the preset first reference temperature, the opening degree of the downstream control valve 161 is increased, and the temperature of the fuel discharged from the primary heating unit 151 is increased. When the temperature of the fuel is higher than the first reference temperature, the opening degree of the downstream control valve 161 is decreased.

When the opening degree of the downstream control valve 161 increases, the amount of feed water flowing into the primary heating unit 151 for heating increases, so that the temperature of the fuel can be increased. In addition, when the opening degree of the downstream control valve 161 decreases, the amount of water supplied to the primary heating unit 151 for heating decreases, so that the temperature of the fuel can be lowered.

In addition, in the valve control step, when the temperature of the fuel discharged from the secondary heating unit 152 is lower than the preset second reference temperature, the opening degree of the fuel control valve 163 is reduced, and the fuel control valve 163 is closed. If so, the degree of opening of the intermediate control valve 162 is increased.

In addition, in the valve control step, when the temperature of the fuel discharged from the secondary heating unit 152 is higher than the second reference temperature, the opening degree of the fuel control valve 163 is increased, and when the fuel control valve 163 is completely opened, the The degree of opening of the control valve 162 is reduced.

When the opening degree of the fuel control valve 163 is reduced, the amount of bypassed fuel is reduced, so the temperature of the fuel rises. As the flow rate of the fuel increases, the temperature of the fuel may rise.

On the other hand, if the opening degree of the fuel control valve 163 is increased, the amount of bypassed fuel is increased, so that the temperature of the fuel is decreased. As the flow rate of the incoming feedwater is reduced, the temperature of the fuel may drop.

When the bypass pipe 156 and the fuel control valve 163 are installed as in the second embodiment, it is possible to effectively prevent overheating of the fuel while minimizing the amount of feed water used for preheating the fuel.

Hereinafter, a combined power generation system according to a third embodiment of the present invention will be described. 6 is a configuration diagram illustrating a fuel preheater according to a third embodiment of the present invention.

Referring to FIG. 6 , the combined cycle power generation system according to the third embodiment has the same structure as the combined cycle power generation system according to the first exemplary embodiment except for the intermediate pressure control valve 165 , so that the A duplicate description will be omitted.

An intermediate pressure control valve 165 for controlling the flow rate of water supplied from the water supply control pipe 154 to the water supply transmission pipe 155 is installed in the water supply control pipe 154 . The intermediate pressure control valve 165 controls the inflow of low-temperature feed water supplied through the water supply control pipe 154 as well as preventing the reverse flow of the feed water. Accordingly, the temperature of the water supply flowing into the primary heating unit 151 through the water supply control pipe 154 can be more easily adjusted.

Meanwhile, a bypass pipe 156 for supplying fuel to the downstream side of the secondary heating unit 152 without passing through the primary heating unit 151 and the secondary heating unit 152 is connected to the fuel supply pipe 157 . . In addition, a fuel control valve 163 for controlling the flow rate of fuel moving through the bypass pipe 156 is installed in the bypass pipe 156 .

Hereinafter, a method of driving a combined cycle power generation system according to a third embodiment of the present invention will be described.

Since the driving method of the combined cycle power generation system according to the third embodiment is the same as the driving method of the combined cycle power generation system according to the third embodiment, except for the valve control step, redundant description of the same configuration will be omitted.

In the valve control step, the temperature of fuel is controlled by adjusting the downstream control valve 161 , the intermediate control valve 162 , the fuel control valve 163 , and the intermediate pressure control valve 165 . In the valve control step, when the temperature of the fuel discharged from the primary heating unit 151 is lower than the preset first reference temperature, the opening degree of the intermediate pressure control valve 165 is reduced and the opening degree of the downstream control valve 161 is decreased. increase On the other hand, when the temperature of the fuel discharged from the primary heating unit 151 is higher than the first reference temperature, the opening degree of the intermediate pressure control valve 165 is increased and the opening degree of the downstream control valve 161 is decreased.

When the opening degree of the intermediate pressure control valve 165 is reduced, the flow rate of the intermediate pressure water supply having a relatively low temperature decreases, so the temperature of the water supply flowing into the primary heating unit increases, and when the opening degree of the intermediate pressure control valve 165 increases Since the flow rate of the medium-pressure feedwater having a relatively low temperature increases, the temperature of the feedwater flowing into the primary heating unit may drop.

In addition, in the valve control step, when the temperature of the fuel discharged from the secondary heating unit 152 is lower than the preset second reference temperature, the opening degree of the fuel control valve 163 is reduced, and the fuel control valve 163 is closed. If so, the degree of opening of the intermediate control valve 162 is increased.

In addition, in the valve control step, when the temperature of the fuel discharged from the secondary heating unit 152 is higher than the second reference temperature, the opening degree of the fuel control valve 163 is increased, and when the fuel control valve 163 is completely opened, the The degree of opening of the control valve 162 is reduced.

When the intermediate pressure control valve 165 is installed as in the third embodiment, it is possible to effectively control the heating temperature of fuel by controlling the flow rate of medium pressure water flowing into the water supply transmission pipe 155 through the water supply control pipe 154. can

Hereinafter, a combined power generation system according to a fourth embodiment of the present invention will be described. 7 is a configuration diagram illustrating a fuel preheater according to a fourth embodiment of the present invention.

7, since the combined cycle power generation system according to the fourth embodiment has the same structure as the combined cycle power generation system according to the first embodiment, except for the bypass pipe 166, the A duplicate description will be omitted.

A bypass pipe 166 for supplying fuel to the upstream side of the secondary heating unit 152 without passing through the primary heating unit 151 is connected to the fuel supply pipe 157 . In addition, a fuel control valve 167 for controlling the flow rate of fuel moving through the bypass pipe 166 is installed in the bypass pipe 166 .

One end of the bypass pipe 166 is connected to the upstream side of the primary heating unit, and the other end of the bypass pipe 166 is connected to the fuel supply pipe between the primary heating unit 151 and the secondary heating unit 152 . Connected. Accordingly, the bypass pipe 166 bypasses only the primary heating unit 151 , and fuel moving through the bypass pipe 166 flows into the secondary heating unit 152 .

Hereinafter, a method of driving a combined cycle power generation system according to a fourth embodiment of the present invention will be described.

Since the driving method of the combined cycle power generation system according to the fourth embodiment is the same as the driving method of the combined cycle power generation system according to the fourth embodiment except for the valve control step, redundant description of the same configuration will be omitted.

The valve control step includes a downstream control valve 161 for controlling the quantity of water discharged from the primary heating unit 151 and controlling the movement of water supply between the primary heating unit 151 and the secondary heating unit 152 . By controlling the fuel control valve 167 installed in the bypass pipe 166 that supplies fuel to the upstream side of the secondary heating unit 152 without passing through the intermediate control valve 162 and the primary heating unit 151, Adjust the temperature.

In the valve control step, when the temperature of the fuel discharged from the primary heating unit 151 is lower than the preset first reference temperature, the opening degree of the downstream control valve 161 is increased, and the temperature of the fuel discharged from the primary heating unit 151 is increased. When the temperature of the fuel is higher than the first reference temperature, the opening degree of the downstream control valve 161 is reduced.

In addition, in the valve control step, when the temperature of the fuel discharged from the secondary heating unit 152 is lower than the preset second reference temperature, the opening degree of the fuel control valve 167 is reduced, and the fuel control valve 167 is closed. If so, the degree of opening of the intermediate control valve 162 is increased.

In addition, in the valve control step, when the temperature of the fuel discharged from the secondary heating unit 152 is higher than the second reference temperature, the opening degree of the fuel control valve 167 is increased, and when the fuel control valve 167 is completely opened, the The degree of opening of the control valve 162 is reduced.

When the bypass pipe 166 and the fuel control valve 167 are installed as in the fourth embodiment, it is possible to effectively prevent overheating of the fuel while minimizing the amount of feed water used for preheating the fuel.

Above, an embodiment of the present invention has been described, but those of ordinary skill in the art can add, change, delete or add components within the scope that does not depart from the spirit of the present invention described in the claims. The present invention may be variously modified and changed by such as, and it will be said that it is also included within the scope of the present invention.

100: combined cycle power system 110: gas turbine
112: compressor 115: combustor
113: main turbine 120: steam turbine
121: condenser 122: condensate storage tank
123: condensate pump 130: generator
140: heat recovery boiler 141: condensate preheater
142: low pressure evaporator 143: medium pressure economizer
144: medium pressure evaporator 145: high pressure economizer
146: high pressure evaporator 147: low pressure drum
148: medium pressure drum 149: high pressure drum
150: fuel preheater 151: primary heating unit
152: secondary heating unit 153: high-pressure water supply pipe
154: water control pipe 155: water delivery pipe
156, 166: bypass pipe 161: downstream control valve
162: intermediate control valve 163, 167: fuel control valve
165: medium pressure control valve 172: medium pressure pump
173: high pressure pump 175: deaerator
176: high pressure valve 181: steam supply line
182: turbine feed water return line

Claims (20)

a gas turbine that burns fuel to generate rotational force;
an exhaust heat recovery boiler that heats feedwater using the combustion gas discharged from the gas turbine and has a high-pressure part, a medium-pressure part, and a low-pressure part having different pressure levels;
a fuel preheater heating the fuel supplied to the gas turbine and having a primary heating unit and a secondary heating unit;
a high-pressure water supply pipe connected to the high-pressure part to supply high-pressure water to the secondary heating part;
a water supply transmission pipe connecting the secondary heating unit and the primary heating unit to supply water discharged from the secondary heating unit to the primary heating unit;
a water supply control pipe connected to the medium pressure unit to supply medium pressure water to the water supply pipe;
an intermediate control valve installed between the primary heating unit and the secondary heating unit to control a flow rate of high-pressure water flowing into the secondary heating unit;
Combined power generation system comprising a. The method of claim 1,
The intermediate pressure unit includes a medium pressure pump that pressurizes and moves the water supply, and a medium pressure economizer that receives the water supply from the medium pressure pump and heats the water supply,
The water supply control pipe is connected between the medium pressure pump and the medium pressure economizer to receive the water supply from the medium pressure pump combined power generation system. The method of claim 1,
The intermediate control valve is a combined power generation system for controlling the flow rate of the medium pressure water supply flowing in from the water supply control pipe by using a change in the flow rate of the high pressure water supply. The method of claim 1,
The high-pressure unit includes a high-pressure economizer for heating the feedwater, a high-pressure drum for storing the feedwater heated in the high-pressure economizer, and a high-pressure evaporator for heating the water in the high-pressure drum and converting it into steam,
The high-pressure water supply pipe is connected between the high-pressure economizer and the high-pressure drum to receive the supply water heated by the high-pressure economizer. The method of claim 1,
The intermediate control valve is a combined power generation system located between the secondary heating part and the connection part to which the water supply control pipe and the water supply transmission pipe are connected. The method of claim 1,
Combined power generation system comprising: a feed water recovery pipe for delivering the feed water discharged from the primary heating unit to the heat recovery boiler; and a downstream control valve installed in the feed water recovery pipe to control the flow rate of feed water discharged from the primary heating unit . 7. The method of claim 6,
The combined power generation system in which the surplus high-pressure water discharged from the secondary heating unit by the downstream control valve is supplied to the medium-pressure economizer through the water supply control pipe. The method of claim 1,
Combined power generation further comprising a bypass pipe connecting the upstream of the primary heating unit and the downstream of the secondary heating unit to bypass the primary heating unit and the secondary heating unit to move fuel downstream of the secondary heating unit system. The method of claim 1,
The combined power generation system further comprising a bypass pipe connecting the upstream of the primary heating unit and the upstream of the secondary heating unit to bypass the primary heating unit and move fuel to the secondary heating unit. 10. The method according to claim 8 or 9,
A combined power generation system in which a fuel control valve for controlling the flow rate of fuel moving through the bypass pipe is installed in the bypass pipe. The method of claim 1,
The combined power generation system having the same capacity as the primary heating unit and the secondary heating unit. The method of claim 1,
In the water supply control pipe, a medium pressure control valve for controlling the flow rate of water supplied from the water supply control pipe to the water supply transmission pipe is installed in the combined power generation system. A combined power generation system comprising a gas turbine, a steam turbine, a heat recovery boiler, and a fuel preheater having a primary heating unit and a secondary heating unit for preheating fuel, wherein the heat recovery boiler includes a low pressure unit, a medium pressure unit, and a high pressure unit In the driving method,
a fuel preheating step of supplying the feed water heated by the high pressure part to the secondary heating part, mixing the feed water discharged from the secondary heating part and the supply water supplied from the intermediate pressure part, and supplying it to the primary heating part;
a fuel temperature determination step of measuring the temperature of the fuel discharged from the primary heating unit and the temperature of the fuel discharged from the secondary heating unit and comparing the temperature with a reference temperature; and
A valve for controlling the temperature of fuel by regulating a downstream control valve for controlling the flow rate of feed water discharged from the primary heating unit and an intermediate control valve for controlling movement of feed water between the primary heating unit and the secondary heating unit control stage;
A method of driving a combined cycle power generation system comprising a. 14. The method of claim 13,
In the fuel preheating step, mixing the water supplied through the water supply control pipe connected between the medium pressure pump and the medium pressure economizer of the medium pressure unit with the water discharged from the secondary heating unit and supplying it to the primary heating unit Driving the combined power generation system Way. 15. The method of claim 14,
The fuel preheating step is a driving method of a combined power generation system of supplying water to the secondary heating unit through a high-pressure water supply pipe connected between the high-pressure economizer and the high-pressure drum of the high-pressure unit. 14. The method of claim 13,
In the valve control step, when the temperature of the fuel discharged from the primary heating unit is lower than a preset first reference temperature, the opening degree of the downstream control valve is increased, and the temperature of the fuel discharged from the primary heating unit is lower than the first reference temperature. When it is higher than the first reference temperature, the degree of opening of the downstream control valve is reduced,
When the temperature of the fuel discharged from the secondary heating unit is lower than the preset second reference temperature, the opening degree of the intermediate control valve is increased, and the temperature of the fuel discharged from the secondary heating unit is lower than the second reference temperature. A method of driving a combined cycle power system to decrease the opening degree of the intermediate control valve when high. 14. The method of claim 13,
In the valve control step, the temperature of the fuel is controlled by adjusting a fuel control valve installed in a bypass pipe for supplying fuel to a downstream side of the secondary heating unit by bypassing the primary heating unit and the secondary heating unit, When the temperature of the fuel discharged from the heating unit is lower than a preset second reference temperature, the degree of opening of the fuel control valve is reduced, and when the fuel control valve is closed, the degree of opening of the intermediate control valve is increased. of the driving method. 18. The method of claim 17,
In the valve control step, when the temperature of the fuel discharged from the secondary heating unit is higher than the second reference temperature, the opening degree of the fuel control valve is increased, and when the fuel control valve is fully opened, the intermediate control valve is opened A method of driving a combined cycle power system to reduce the degree. 14. The method of claim 13,
The valve control step adjusts the temperature of the fuel by adjusting the intermediate pressure control valve for controlling the flow rate of water supplied from the intermediate pressure unit,
When the temperature of the fuel discharged from the primary heating unit is lower than the preset first reference temperature, the opening degree of the intermediate pressure control valve is decreased and the opening degree of the downstream control valve is increased, and the discharge from the primary heating part When the temperature of the used fuel is higher than the first reference temperature, the driving method of the combined cycle power system for increasing the opening degree of the intermediate pressure control valve and decreasing the opening degree of the downstream control valve. 14. The method of claim 13,
In the valve control step, the temperature of the fuel is controlled by controlling a fuel control valve installed in a bypass pipe that bypasses the primary heating unit and supplies fuel to an upstream side of the secondary heating unit, but the fuel discharged from the secondary heating unit. When the temperature of is lower than the preset second reference temperature, the opening degree of the fuel control valve is reduced, and when the fuel control valve is closed, the opening degree of the intermediate control valve is increased, and the secondary heating unit is discharged When the fuel temperature is higher than the second reference temperature, the opening degree of the fuel control valve is increased, and when the fuel control valve is fully opened, the opening degree of the intermediate control valve is decreased.

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