A method of operating a gas and steam-turbine plant and gas and steam turbine installation

 

The invention relates to the field of power engineering. A method of operating a gas and steam turbine installation in which the heat contained in the expanded working medium corresponding gas turbine operating on gas and liquid fuel, used to produce steam for the respective steam turbine, containing at least one stage of high pressure. In parallel feedwater heater high pressure stage included the bypass pipe with the valve, which is adjustable depending on the temperature of the condensate supplied to the high pressure stage. The invention improves the efficiency. 2 S. and 2 C.p. f-crystals, 1 Il.

The invention relates to a method of operating a gas and steam-turbine plant, in which heat contained in the expanded working medium corresponding gas turbine that can operate as a fuel gas or liquid fuel is used to produce steam for the respective steam turbine, containing at least one stage of high pressure. It is also particularly suitable for implementing the method of the gas and steam turbine plant with a gas turbine, MotorStorm, connected after the gas turbine on the flue gas side, to produce steam for the corresponding steam turbine, containing at least one stage of high pressure.

In the case of gas and steam turbine heat contained in the expanded working medium of the gas turbine is used to produce steam for the steam turbine. Heat transfer occurs in the connected after the gas turbine on the flue gas side, running on waste heat steam generator, in which are located the heating surfaces in the form of tubes or tube bundles. They, in turn, included in the water / steam circuit of a steam turbine. The steam-water circuit contains one or more, for example two or three pressure stages, with each stage pressure typically contains the heating surface of the heater (economizer), evaporative heating surface and the overheating of the heating surface. With such known, for example, from EP 0148973 B1 gas and steam-turbine plant, depending on the ruling in the water / steam circuit of the steam turbine pressure ratios is achieved thermodynamic efficiency of about 50% or more.

The gas turbine is similar to the gas and steam turbine in which the values in the basis of calculation, requirements for working in the waste heat to the steam generator, connected after the gas turbine on the flue gas side, however, are different. For example, gas as fuel for gas turbines is usually of high purity, so that in the output from the gas turbine flue gas contains only small amounts of impurities.

In contrast, in the case of a fuel boiler as fuel for the gas turbine should be considered with pollution resulting from the gas turbine flue gas. This may occur, in particular, sulfur dioxide (SO2) or sulfur trioxide (SO3), which settles after reaction with water to form sulfuric acid (H2SO4) on the heating surfaces in working in the waste heat steam generator and can corrode them. Therefore, when using liquid fuel as fuel for the gas turbine to working on the waste heat of the steam generator must meet other requirements than when using gas as fuel for gas turbines.

In particular, when using liquid fuel as fuel for the gas turbine should ensure that included in the water / steam circuit of a steam turbine heating surface and C is the atur, namely, the temperature above the dew point of sulfuric acid. When the gas turbine liquid fuel inlet temperature water or condensate flowing in working in the waste heat steam generator, in comparison with the operation of gas turbines on gas increase and regulate to about 120oC-130oC.

Gas and steam turbine installation in which the fuel for the gas turbine liquid fuel is provided only for a short time of operation, such as 500-1.500 hours/year as a "reserve" for natural gas, usually expect optimirror primarily for operation of gas turbines on natural gas. So that during operation of the gas turbine liquid fuel to provide sufficiently high inlet temperature of the condensate flowing in working in the waste heat steam generator, the necessary heat can be extracted in different ways from working in the waste heat steam generator.

One possibility is to partially or completely bypass is usually provided for the condensate preheater to heat the condensate in the steam-water circuit the feedwater tank by supplying low-pressure steam. This method tremu cogeneration steam in the feedwater tank, when large periods of heating may adversely affect usually taking place in the tank feedwater function obezvozhivanija.

To ensure the effective obezvozhivanija condensation temperature of the condensate in the feedwater tank constant in the temperature range between 130oC and 160oC, and the period of heating the condensate in the feedwater tank must be supported by capabilities small. This can be accomplished, for example, by heating the condensate through an additional heater, heated by means of steam.

In order to provide enough heat, in the case of installations with two or three pressures is often essential selection hot water from the high pressure economizer operating in the waste heat steam generator. It has, at least in installations with three pressures, lack, which is usually provided with nutritious high-pressure pump may be exposed to with respect to its performance and that additional heater condensate especially uneconomical way shall be designed for high pressure and large temperature differences.

In addition, not what about the pump or each feed pump. Further, the selection of hot water from the high pressure economizer reduces the amount of high pressure steam by lowering the so-called temperature approach at high pressure, which in turn leads to a decrease in the efficiency of the installation.

Another proven method is to maintain during operation of the gas turbine liquid fuel heating condensate in the feedwater tank or in the crystallizer vapor selected from the pipeline intermediate superheater. This method, however, is not applicable in the case of plants without the tank feedwater or without degasser.

From EP 0400370 A2 is known a method of operating a gas and steam turbine installation in which the heat contained in the expanded working medium corresponding gas turbine operating on gas and liquid fuel, used to produce steam for the respective steam turbine, containing at least one stage of high pressure. From EP 0400370 A2 is also known for gas and steam turbine gas turbine operating on gas or liquid fuel, and enabled after the gas turbine on the flue gas side, working in the waste heat steam generator is placed and the stage of high pressure.

Named concept for heating condensate when using liquid fuel as fuel for gas turbines are complex due to the necessary components and also in connection with the operation mode of the gas and steam turbine installation. In addition, the efficiency of the installation during operation of the gas turbine liquid fuel is limited.

The basis of the invention is the task of creating a method for operating a gas and steam turbine installation in which the heat contained in the expanded working medium corresponding gas turbine working gas flowed and liquid fuel is used to produce steam for the respective steam turbine, containing at least one stage of high pressure, where small equipment and operational costs, regardless of the applied fuel for the gas turbine is achievable particularly high efficiency of the installation. Furthermore, it should be specified which is especially suitable for implementing the method of the gas and steam turbine installation.

This problem is solved in a method of operating a gas and steam-turbine plant, in which heat contained in the expanded working environments the Ara for the corresponding steam turbine, containing at least one stage of high pressure so that after the transfer of the gas turbines run on gas for work on liquid fuel feed water for high pressure stage is divided into first and second partial flow and heat only one of the partial flows.

The invention proceeds from the consideration that when the gas turbine liquid fuel is also necessary to heat the condensate is provided with particularly simple means and is particularly simple manner due to the fact that the necessary heat transfer for condensation not through the steam-water circuit, and across the flue gas from the gas turbine. You can unsubscribe from those required for the transfer of heat through the steam-water circuit components, such as heat exchangers, heaters mixing type, steam pressure reducing installation and/or associated piping. Instead, when the gas turbine liquid fuel in a suitable place, reduce the heat extraction from the flue gas of a gas turbine in comparison with the operation of gas turbine gaseous fuel so that there is enough heat the exhaust gas to preheat condensate.

For appropriate changes selection th the help of a steam turbine. In the case of gas and steam turbine installation, made in the form of installation with three pressures, may provide alternative or additional appropriate, depending on the type of work the change of the heated feedwater to the secondary pressure.

In the preferred form of further development after switching the gas turbine operation on gaseous fuel operation to liquid fuel increase the operating pressure in the low pressure stage of the steam turbine. Due to this, ensure that when the gas turbine liquid fuel due to the relatively smaller heating feed water for high pressure stage remaining in the flue gas heat is not passed through the heating surface low pressure steam circuit of a steam turbine, and really sent further in the flue gas and thereby reliably provide for heating of the condensate.

Working pressure in the low pressure stage can be adjusted in such a way that the production of steam in the low pressure stage is terminated. Suitable operating pressure in the low pressure stage of a steam turbine, however, to raise thus, for example, up to about 10-15 the lending functions.

For particularly high efficiency also in the transition phase after the change of the operation of the gas turbine, the branching ratio between the first and second partial stream set the preferred way depending on the temperature of the condensate to be connecting to the high pressure stage. In this case, the temperature of the condensate flowing in working in the waste heat steam generator may be controlled in a particularly advantageous way.

The basis of the invention also given the task of creating a gas and steam-turbine plant with a gas turbine operating on gas or liquid fuel, and enabled after the gas turbine on the flue gas side, working in the waste heat steam generator to produce steam for the corresponding steam turbine, containing at least one stage of the low pressure stage high pressure which achieves high efficiency.

This task is achieved in a gas and steam turbine plant with a gas turbine operating on gas or liquid fuel, and enabled after the gas turbine on the flue gas side, running on waste heat steam generator to produce steam for the matched what I in parallel with the heater feed water high pressure stage included the bypass pipe with the valve, which is adjustable depending on the temperature of the condensate supplied to the high pressure stage.

Benefits advantages of the invention consist, in particular, that are necessary when working in the gas turbine liquid fuel compared to gas turbine gaseous fuel high temperature water inlet in working in the waste heat steam generator provided with particularly simple means. Usually provided with the necessary additional heating of the condensate complex components for transferring heat from the steam-water circuit on the condensate, for example, by summing the low-pressure steam can fall away. Instead, a sufficient transfer of heat to the condensate due to the fact that in the flue gas from the gas turbine in the area of the heater condensate still contains enough heat. Required when operating a gas turbine liquid fuel additional heat for heating the condensate is passed so the condensate directly through the flue gas. Required for this design is antura, as, for example, the feedwater pumps high pressure, can be calculated with relatively low settings, as they should not be designed for the loop operation during operation of the gas turbine liquid fuel with additional sampling of water from the economizer. In addition, depending on the execution of the low pressure stage of the steam turbine and condensate pump can cope with temperatures of water input running on waste heat steam generator to about 130oC. So you can almost cover the entire range of liquid fuels for this purpose (reserve fuel), so the possible standardization.

An example of carrying out the invention is explained in more detail using the drawing, which shows schematically the gas and steam turbine installation.

Gas and steam turbine installation 1 according to the drawing comprises a gas turbine installation 1A and steam turbine installation 1b. Gas turbine unit 1A comprises a gas turbine 2 with compressor 4 and is connected in front of the gas turbine 2 combustion chamber 6, which is connected to the pipeline of fresh air 8 air compressor 4. In the combustion chamber 6 of the gas turbine 2 includes a fuel line 10, through which the camera SGAs what I turbine 2 and the air compressor 4, and the generator 12 are sitting on a common shaft 14.

Steam turbine 1b covers the steam turbine 20 is connected by the generator 22 and is included in the water / steam circuit 24 after the steam turbine 20, the capacitor 26, and also working on the waste heat steam generator 30. Steam turbine 20 consists of a first pressure stage or part of the high pressure 20A and the second pressure stage or part of the medium pressure 20b, and a third pressure stage or part of the low pressure 20s, which via a common shaft 32 trigger generator 22.

To summarize expanded in the gas turbine 2 AM working environment or flue gas in working in the waste heat steam generator 30, the off-gas pipeline 34 is connected to the input 30A running on waste heat steam generator 30. The expanded working medium AM from the gas turbine 2 leaves running on waste heat steam generator 30 through its exit 30b toward not represented in more detail the chimney.

Working in the waste heat steam generator 30 includes a first condensate preheater 40, which on the inlet side through the condensate pipeline 42, which is included in the unit condensate pump 44 is fed from the condensate from the condenser 26. Podagra the ATA 42 through a lockable gate 47 circulation pipe 48, which includes a circulation pump 49 is connected to the condensate pipeline 42. Through the circulation pipe 48, the condensate pipeline 42, the condensate preheater 40 and the condensate pipeline 45 thus formed a circulation loop for the condensate so that the feedwater tank is not required. If necessary, to bypass the high pressure heater 40 pipeline condensate 42 may be also directly connected to the high-pressure pump 46 through not shown in the drawing the bypass pipeline.

The high-pressure pump 46 carries resulting from the condensate preheater 40 heated condensate To a pressure level suitable for dowry in accordance steam turbine 20 of the high pressure stage 50 of water-steam circuit 24. At high pressure condensate is supplied to the high pressure stage 50 as feed water S through the superheater feed water 52, which is connected on the output side through the overlapped valve 54 feedwater pipeline 56 to the drum high pressure 58. Dryer high pressure 58 is connected with located in working in the waste heat steam generator 30 evaporator high ducen situated in working in the waste heat steam generator 30 superheater high pressure 64, which is connected on the outlet side with the inlet steam 66 parts of high pressure 20A of the steam turbine 20.

The steam release 68 parts of high pressure 20A steam turbine 20 through the intermediate superheater 70 is connected to the steam inlet 72 of the part of the medium-pressure steam turbine 20b 20. Its steam release 74 is connected through the bypass pipe 76 with the steam inlet 78 of the low pressure 20s steam turbine 20. The steam release 80 parts low-pressure 20s steam turbine 20 through the steam line 82 is connected to the capacitor 26 so that there is a closed steam circuit 24.

From the high-pressure pump 46 branches off to the same place in which the condensate To achieved an average pressure drop of the pipe 84. It is connected through a second feedwater heater 86 dowry in accordance steam turbine 20 secondary pressure 90 water-steam circuit. The second feedwater heater 86 is connected on the output side via the feedwater pipeline 94 blocked by a valve 92, to the medium-pressure drum 96 of the secondary pressure 90. The medium-pressure drum 96 is connected with located in working in the waste heat steam generator 30 by medium-pressure evaporator 98 for education privodanova 102 to the intermediate superheater and thereby to the inlet of the pair 72 of the part of the medium-pressure steam turbine 20b 20.

When considering in the direction of flow of the condensate To block condensate pump 44 from the condensate drain line 42 branches off to the same additional condensate pipeline 104, which is located in working in the waste heat steam generator 30 second condensate preheater 106. The second condensate preheater 106 is connected on the output side through the overlapped valve 108 condensate pipeline 110 dowry in accordance steam turbine 20 stage low pressure 120 water-steam circuit 24.

Stage low pressure 120 contains a low pressure drum 122, which is connected with located in working in the waste heat steam generator 30 evaporator low pressure 124 for the formation of water-steam cycle 126. For discharge of the fresh low pressure steam F low pressure drum 122 is connected through a steam line 128 to the bypass pipe 76. The condensate pipeline 110 through the overlapped valve 130 circulation pipe 132, which includes the circulation pump 134 is connected to the same condensate pipeline 104. Through the circulation pump 134 condensate To can circulate inside the circulation pipe 132, the pipeline condense the tion of water is not required. To bypass if necessary the condensate preheater 106 condensate pipeline 104 may be also directly connected to the condensate pipeline 110 through not shown in the drawing the bypass pipeline.

Parallel to the feedwater heater 52, attached to the high pressure stage 50, enabled blocked by the valve 140 bypass pipe 142. The valve 140 is controlled depending on the temperature of the condensate To be summing up to a high pressure stage 50 or secondary pressure 90. For this purpose, the valve 140, not represented in more detail by way connected with the control unit to which is applied an input signal characteristic of the temperature of the condensate To be summing up to a high pressure stage 50 or secondary pressure 90.

Parallel to the feedwater heater 86, awarded in compliance secondary pressure 90, also included is blocked by a valve 144 bypass pipe 146. The valve 144 is adjustable in a similar manner as and gate 140, depending on the temperature of the condensate To be summing up to a high pressure stage 50 or secondary pressure is In gas and liquid fuel. During operation of the gas turbine 2 gas supplied to a waste heat steam generator 30 AM working environment has a relatively high purity, so that the water / steam circuit 24 in this state of operation respect to its efficiency can be optimized. In this state, the operation of the valves 140, 144 are closed, so that all of the supplied high-pressure pump 46 feed water 5 is directed through the feedwater heater 52 or 86 respectively and there is preheated.

During operation of the gas turbine 2A liquid fuel supplied to a waste heat steam generator 30 AM working environment may contain impurities, particularly sulfur dioxide (SO2and sulfuric acid, H2SO4. So in this state of operation to reliably avoid damage to the parts inside running on waste heat steam generator 30, all located in working in the waste heat steam generator 30 of the heating surface, that is, in particular, the condensate preheater 40 and the condensate preheater 106 operate with a temperature higher than the dew point of sulfuric acid. To do this, compared with the work of the gas turbine 2 in g the steam generator 30, and thus relatively strong heating of the condensate.

This relatively strong heating of the condensate is not due to heat transfer from the water / steam circuit 24 to the condensate To, but more due to the transfer of heat from the working medium AM directly on the condensate K. To do this, after transfer of the gas turbine 2 with a run on gas for work on liquid fuel to be summing up to a high pressure stage 50 and the secondary pressure 90 feed water S share, respectively, on the first partial flow T1 and a second partial flow T2, and heated, respectively, only one of the partial streams T1, T2.

To achieve this, the valves 140 and 144, respectively, partially open, so be summing up to a high pressure stage 50 of the flow of feed water is distributed to the feedwater heater 52 and the bypass pipe 142. Similarly, the flow of feed water to be summing up to a secondary pressure 90 is allocated to the feedwater heater 86 and to the bypass pipe 146. Due to this, from the working medium AM in the field of feedwater heater 52, 86 selected less heat in comparison with the work of the gas turbine 2 gas.

To ensure to the low pressure stage 120 to about 10-15 bar. Thereby avoiding the reception additionally remaining in the working environment AM heat through the evaporator low pressure 124. Due to this ensured reliable additional heating of the condensate To the condensate heaters 40, 106.

Gas and steam turbine 1 is operated at temperatures of inlet condensate To operating the waste heat steam generator 30 to over 130oC. Thus, for the gas turbine 2 can apply to a wide range of liquid fuels (fuel reserve) so that it is possible to standardize gas and steam turbine installation 1 regardless of the liquid fuel.

Claims

1. A method of operating a gas and steam turbine installation in which the heat contained in the expanded working medium corresponding gas turbine operating on gas and liquid fuel, used to produce steam for the respective steam turbine, containing at least one stage of high pressure, characterized in that after the transfer of the gas turbines run on gas for work on liquid fuel feed water for high pressure stage is divided into first and second partial flow and heat only one of the partial p of the liquid fuel to increase the operating pressure in the low pressure stage of the steam turbine.

3. The method according to p. 1 or 2, characterized in that the branching ratio between the first partial flow and a second partial flow is established depending on the temperature of the condensate to be connecting to the high pressure stage.

4. Gas and steam turbine gas turbine operating on gas or liquid fuel, and enabled after the gas turbine on the flue gas side, running on waste heat steam generator to produce steam for the corresponding steam turbine, containing at least one stage of the low pressure stage to the high pressure, characterized in that parallel to the feedwater heater high pressure stage included the bypass pipeline, with the inclusion of a valve, which is adjustable depending on the temperature of the condensate supplied to the high pressure stage.

 

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