CA2352474C - Retrofit system for electrical power generating stations and method - Google Patents
Retrofit system for electrical power generating stations and method Download PDFInfo
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- CA2352474C CA2352474C CA 2352474 CA2352474A CA2352474C CA 2352474 C CA2352474 C CA 2352474C CA 2352474 CA2352474 CA 2352474 CA 2352474 A CA2352474 A CA 2352474A CA 2352474 C CA2352474 C CA 2352474C
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- 238000000034 method Methods 0.000 title claims abstract description 23
- 239000000446 fuel Substances 0.000 claims abstract description 80
- 239000007789 gas Substances 0.000 claims abstract description 63
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims abstract description 43
- 238000011084 recovery Methods 0.000 claims abstract description 38
- 239000003345 natural gas Substances 0.000 claims abstract description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 35
- 230000005611 electricity Effects 0.000 claims description 21
- 238000002485 combustion reaction Methods 0.000 claims description 7
- 238000004064 recycling Methods 0.000 claims 4
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 9
- 230000008020 evaporation Effects 0.000 description 6
- 238000001704 evaporation Methods 0.000 description 6
- 239000003245 coal Substances 0.000 description 5
- 239000003921 oil Substances 0.000 description 5
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 239000003344 environmental pollutant Substances 0.000 description 3
- 239000005431 greenhouse gas Substances 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- XLYOFNOQVPJJNP-ZSJDYOACSA-N Heavy water Chemical compound [2H]O[2H] XLYOFNOQVPJJNP-ZSJDYOACSA-N 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000000254 damaging effect Effects 0.000 description 2
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 239000012855 volatile organic compound Substances 0.000 description 2
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 description 1
- 238000003916 acid precipitation Methods 0.000 description 1
- 239000000809 air pollutant Substances 0.000 description 1
- 231100001243 air pollutant Toxicity 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 239000000295 fuel oil Substances 0.000 description 1
- 239000003758 nuclear fuel Substances 0.000 description 1
- 239000010742 number 1 fuel oil Substances 0.000 description 1
- 230000003389 potentiating effect Effects 0.000 description 1
- 239000002243 precursor Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000009420 retrofitting Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000004291 sulphur dioxide Substances 0.000 description 1
- 235000010269 sulphur dioxide Nutrition 0.000 description 1
- 239000003053 toxin Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K23/00—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids
- F01K23/02—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled
- F01K23/06—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle
- F01K23/10—Plants characterised by more than one engine delivering power external to the plant, the engines being driven by different fluids the engine cycles being thermally coupled combustion heat from one cycle heating the fluid in another cycle with exhaust fluid of one cycle heating the fluid in another cycle
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C6/00—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use
- F02C6/18—Plural gas-turbine plants; Combinations of gas-turbine plants with other apparatus; Adaptations of gas-turbine plants for special use using the waste heat of gas-turbine plants outside the plants themselves, e.g. gas-turbine power heat plants
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Engine Equipment That Uses Special Cycles (AREA)
Abstract
Apparatus for, wholly or partly, converting an existing polluting fuel electrical generating station, from a polluting fuel to natural gas, while retaining the existing steam turbine electrical generator of the existing station and having, a gas turbine, a gas turbine powered electrical generator which supplies power to a grid, a heat recovery steam generator connected to the exhaust of the gas turbine to generate steam, and, a steam connection between the heat recovery steam generator, and the existing steam turbine electrical generator in the existing plant, so that the converted plant generates a first electrical supply from the gas turbine powered generator, and generates a second electrical supply from the existing steam turbine powered generator. Also disclosed is a method of converting an existing polluting fuel electrical generating station, to natural gas, while retaining the existing steam turbine electrical generator of the existing station in which a gas turbine prime drives an electrical generator, for generating a first electrical supply, the exhaust from the gas turbine being connected to an heat recovery steam boiler, and in which the heat recovery steam boiler is connected to drive the steam turbine of the existing generating plant to generate a second electrical supply.
The polluting fuel steam boiler of the existing plant may be wholly or partly disconnected from the existing steam turbine.
The polluting fuel steam boiler of the existing plant may be wholly or partly disconnected from the existing steam turbine.
Description
FIELD OF THE INVENTION
Retrofit conversion of existing conventional thermal fuelled electrical power generators with a system utilizing natural gas and steam generators, thereby reducing the amount of pollutants released into the atmosphere and increasing the efficiency of the generating station, for a given unit value of fuel.
BACKGROUND OF THE INVENTION
Existing conventional power stations presently fired by regulated fuel sources, such as coal and oil burning generators, are considered major polluters of the environment. Key air pollutants are nitrogen oxides (NOx), sulphur dioxide, (S02), carbon dioxide (C02) and mercury (Hg). Both NOx and SOZ
cause acid rain while NOx, along with volatile organic compounds (VOCs), is an important precursor gas to ozone, a major component of smog. C02 is a key greenhouse gas, contributing to the threat of climate change. Mercury is a potent nerve-toxin that builds up in the food chain.
Burning of these fuels, is considered to be the predominant producer of these gases and greenhouse gases. Since these fuels are non-renewable, continued use of these fuel sources are taxing on the environment. It would be desirable to use alternative fuel sources that would be less taxing on the environment and would burn cleaner and therefore reduce the amount of pollutants and greenhouse gases released into the atmosphere. The same is also true for different reasons for nuclear powered stations.
However capital costs of constructing entire new generation plants, makes it impractical to discard existing old coal, oil fired, and nuclear power plants, and replacing them with entirely new power plants. In most cases existing plants have been written off in the past. They have virtually no resale value.
It is clearly desirable therefore to retain, as far as possible, existing plants, but convert the fuel system to a more efficient and less environmentally damaging system.
This invention outlines the method of retrofitting existing polluting power generating stations for use with natural gas fuel.
The invention also provides an apparatus for carrying out the method. The invention also provides increased efficiency for a given unit value of fuel.
The invention also envisages partial attenuation of use of existing polluting fuels by less polluting fuels, where total replacement is not adequate.
BRIEF SUMMARY OF THE INVENTION
The invention seeks to provide the foregoing improvements by the method of converting an existing thermal electrical generating station, from conventional fuels such as coal/oil, or nuclear power, to natural gas. The method used, includes retaining the existing steam turbine electrical generator of the existing station or other systems which used steam turbines, such as water treatment facilities. The method also includes erecting a gas turbine prime mover along side the existing generating station. The erected gas turbine is used to produce electrical energy by the method of connecting at least one gas turbine prime mover to at least one electrical generator, for generating electricity to be supplied to a supply grid. The method also connects the hot exhaust from at least one gas turbine to at least one heat recovery steam generator and connecting it to the steam turbine of the existing generating plant and either disconnecting the steam boiler or reducing the fuel consumption at the existing generating plant.
The method of operating at least one gas turbine to generate a first supply of electricity, and supplying same to a grid and, operating the steam turbine of the existing generation plant to generate a second supply of electricity and supplying same to a grid.
The methods further comprises the steps of, connecting the steam outlet of the steam turbine back to the heat recovery steam generator, whereby to recycle calorific values of the waste steam.
The method further comprises operating at least one gas turbine by continuous introduction of air, compressing the air, introducing gas into the compressed air, and igniting the gas and compressed air to create a high pressure exhaust of combustion products of gas and air. A gas turbine shaft is coupled to drive a generator to generate electrical power as aforesaid.
The r'nethod further comprises introducing feed water to at least one heat recovery steam generator , and preheating the feed water with condensed steam from the steam turbine of the existing plant.
The invention seeks to achieve the foregoing improvements by providing apparatus for converting all or part of an existing conventional thermal electrical generating station, from a fuel such as, coal/oil, or nuclear to natural gas, while retaining the existing steam turbine and at least one electrical generator of the existing station and in which a gas turbine prime mover is erected adjacent the existing electrical generating station, at least one electrical generator is connected to at least one gas turbine, and is connected to supply power to a grid. The apparatus also includes at least one heat recovery steam generator connected to the exhaust of at least one gas turbine to generate steam. There is at least one steam connection between at least one heat recovery steam generator, and the existing steam turbine, which in turn is connected to at least one electrical generator in the existing plant, whereby the gas powered plant is operable to generate a first electrical supply from the gas turbine powered generators, and to supply steam to generate a second electrical supply from the existing steam turbine powered generator.
The apparatus also includes a steam condenser connected to at least one steam turbine and connected back to at least one heat recovery steam generator.
The apparatus for converting an existing thermal electrical generating station, including a feed water supply connected between at least one heat recovery steam generator and at least one steam condenser, for preheating the feed water.
Retrofit conversion of existing conventional thermal fuelled electrical power generators with a system utilizing natural gas and steam generators, thereby reducing the amount of pollutants released into the atmosphere and increasing the efficiency of the generating station, for a given unit value of fuel.
BACKGROUND OF THE INVENTION
Existing conventional power stations presently fired by regulated fuel sources, such as coal and oil burning generators, are considered major polluters of the environment. Key air pollutants are nitrogen oxides (NOx), sulphur dioxide, (S02), carbon dioxide (C02) and mercury (Hg). Both NOx and SOZ
cause acid rain while NOx, along with volatile organic compounds (VOCs), is an important precursor gas to ozone, a major component of smog. C02 is a key greenhouse gas, contributing to the threat of climate change. Mercury is a potent nerve-toxin that builds up in the food chain.
Burning of these fuels, is considered to be the predominant producer of these gases and greenhouse gases. Since these fuels are non-renewable, continued use of these fuel sources are taxing on the environment. It would be desirable to use alternative fuel sources that would be less taxing on the environment and would burn cleaner and therefore reduce the amount of pollutants and greenhouse gases released into the atmosphere. The same is also true for different reasons for nuclear powered stations.
However capital costs of constructing entire new generation plants, makes it impractical to discard existing old coal, oil fired, and nuclear power plants, and replacing them with entirely new power plants. In most cases existing plants have been written off in the past. They have virtually no resale value.
It is clearly desirable therefore to retain, as far as possible, existing plants, but convert the fuel system to a more efficient and less environmentally damaging system.
This invention outlines the method of retrofitting existing polluting power generating stations for use with natural gas fuel.
The invention also provides an apparatus for carrying out the method. The invention also provides increased efficiency for a given unit value of fuel.
The invention also envisages partial attenuation of use of existing polluting fuels by less polluting fuels, where total replacement is not adequate.
BRIEF SUMMARY OF THE INVENTION
The invention seeks to provide the foregoing improvements by the method of converting an existing thermal electrical generating station, from conventional fuels such as coal/oil, or nuclear power, to natural gas. The method used, includes retaining the existing steam turbine electrical generator of the existing station or other systems which used steam turbines, such as water treatment facilities. The method also includes erecting a gas turbine prime mover along side the existing generating station. The erected gas turbine is used to produce electrical energy by the method of connecting at least one gas turbine prime mover to at least one electrical generator, for generating electricity to be supplied to a supply grid. The method also connects the hot exhaust from at least one gas turbine to at least one heat recovery steam generator and connecting it to the steam turbine of the existing generating plant and either disconnecting the steam boiler or reducing the fuel consumption at the existing generating plant.
The method of operating at least one gas turbine to generate a first supply of electricity, and supplying same to a grid and, operating the steam turbine of the existing generation plant to generate a second supply of electricity and supplying same to a grid.
The methods further comprises the steps of, connecting the steam outlet of the steam turbine back to the heat recovery steam generator, whereby to recycle calorific values of the waste steam.
The method further comprises operating at least one gas turbine by continuous introduction of air, compressing the air, introducing gas into the compressed air, and igniting the gas and compressed air to create a high pressure exhaust of combustion products of gas and air. A gas turbine shaft is coupled to drive a generator to generate electrical power as aforesaid.
The r'nethod further comprises introducing feed water to at least one heat recovery steam generator , and preheating the feed water with condensed steam from the steam turbine of the existing plant.
The invention seeks to achieve the foregoing improvements by providing apparatus for converting all or part of an existing conventional thermal electrical generating station, from a fuel such as, coal/oil, or nuclear to natural gas, while retaining the existing steam turbine and at least one electrical generator of the existing station and in which a gas turbine prime mover is erected adjacent the existing electrical generating station, at least one electrical generator is connected to at least one gas turbine, and is connected to supply power to a grid. The apparatus also includes at least one heat recovery steam generator connected to the exhaust of at least one gas turbine to generate steam. There is at least one steam connection between at least one heat recovery steam generator, and the existing steam turbine, which in turn is connected to at least one electrical generator in the existing plant, whereby the gas powered plant is operable to generate a first electrical supply from the gas turbine powered generators, and to supply steam to generate a second electrical supply from the existing steam turbine powered generator.
The apparatus also includes a steam condenser connected to at least one steam turbine and connected back to at least one heat recovery steam generator.
The apparatus for converting an existing thermal electrical generating station, including a feed water supply connected between at least one heat recovery steam generator and at least one steam condenser, for preheating the feed water.
IN THE DRAWINGS
Figure 1 illustrates Prior art of existing thermal fuel burning power plants, wherein duplicate components are shown in phantom;
Figure 2 illustrates retrofitted power plant using natural gas fuel, wherein duplicate components are shown in phantom.
DESCRIPTION OF A SPECIFIC EMBODIMENT
Referring generally to Figure 1, labeled "Prior Art", it will be seen that the existing power plant, indicated as number (10), consists of an existing fuel source(11) used to fire a boiler(12). Boiler(12) produces steam(13) which is connected to a steam turbine(14). Steam turbine(14) is connected via a turbine shaft(not shown) to an electrical generator(16) for producing electricity which is delivered to a power grid(18). Steam turbine(14) is also connected to a condenser(20), in which steam (13) is condensed to hot water, typically known as condensate(24). The condensate(24) is connected to a make-up water(26) source, a supplementary source used to replace water lost due to evaporation and leakage. The condensate(24) is cycled back to boiler(12). In the case of many existing power plants, coal or heavy oil(11) is used as fuel to fire the boilers to heat water to steam(13). These fuels are regulated resources, and there is public pressure to move away from burning these fuels, due to the high levels of solid and gaseous pollutants. Also, since these fuels are used for other purposes, the conversion of power generating stations will reduce the demand for such fuels, thereby prolonging the lifetime of existing resources. We will refer to boilers using coal , oil or nuclear fuel sources as "existing fuels", throughout the description, for ease of explanation.
It should be noted that this invention may also be applied to nuclear power stations, which also have many environmentally damaging properties, such as threat of heavy water leaks, or radiation contamination.
Currently, to change the fuel burned in a power plant, would entail replacing the boilers, and expensive retooling of the existing equipment. Alternatively, completely new power generating plants would have to be built. Both of these options are expensive endeavors. The capital cost of either alternative would cause a significant and unacceptable increase in the price charged to the consumers of electrical power. It would be desirable to develop a system that could offer a different means of powering the turbine while, use existing equipment as far as possible, and keep the costs of retooling down.
Figure 2 illustrates an embodiment of the invention. In this embodiment the second power plant(28) is erected beside the existing thermal power plant(10). Second power plant(28) includes gas turbine(30), fired by natural gas(32). Gas turbine(30) is connected by a turbine shaft(not shown) to an electrical generator(33).
Electrical generator(33) is connected to grid(18) to which electricity is delivered.
The exhaust(34) from the gas turbine(30) is connected to a heat recovery steam generator(36). The heat from the exhaust(34) is used to produce high pressure steam(38), which is connected to steam turbine(14) of the existing power plant(10), where it is used to produce electricity in a method well known in the art.
Figure 1 illustrates Prior art of existing thermal fuel burning power plants, wherein duplicate components are shown in phantom;
Figure 2 illustrates retrofitted power plant using natural gas fuel, wherein duplicate components are shown in phantom.
DESCRIPTION OF A SPECIFIC EMBODIMENT
Referring generally to Figure 1, labeled "Prior Art", it will be seen that the existing power plant, indicated as number (10), consists of an existing fuel source(11) used to fire a boiler(12). Boiler(12) produces steam(13) which is connected to a steam turbine(14). Steam turbine(14) is connected via a turbine shaft(not shown) to an electrical generator(16) for producing electricity which is delivered to a power grid(18). Steam turbine(14) is also connected to a condenser(20), in which steam (13) is condensed to hot water, typically known as condensate(24). The condensate(24) is connected to a make-up water(26) source, a supplementary source used to replace water lost due to evaporation and leakage. The condensate(24) is cycled back to boiler(12). In the case of many existing power plants, coal or heavy oil(11) is used as fuel to fire the boilers to heat water to steam(13). These fuels are regulated resources, and there is public pressure to move away from burning these fuels, due to the high levels of solid and gaseous pollutants. Also, since these fuels are used for other purposes, the conversion of power generating stations will reduce the demand for such fuels, thereby prolonging the lifetime of existing resources. We will refer to boilers using coal , oil or nuclear fuel sources as "existing fuels", throughout the description, for ease of explanation.
It should be noted that this invention may also be applied to nuclear power stations, which also have many environmentally damaging properties, such as threat of heavy water leaks, or radiation contamination.
Currently, to change the fuel burned in a power plant, would entail replacing the boilers, and expensive retooling of the existing equipment. Alternatively, completely new power generating plants would have to be built. Both of these options are expensive endeavors. The capital cost of either alternative would cause a significant and unacceptable increase in the price charged to the consumers of electrical power. It would be desirable to develop a system that could offer a different means of powering the turbine while, use existing equipment as far as possible, and keep the costs of retooling down.
Figure 2 illustrates an embodiment of the invention. In this embodiment the second power plant(28) is erected beside the existing thermal power plant(10). Second power plant(28) includes gas turbine(30), fired by natural gas(32). Gas turbine(30) is connected by a turbine shaft(not shown) to an electrical generator(33).
Electrical generator(33) is connected to grid(18) to which electricity is delivered.
The exhaust(34) from the gas turbine(30) is connected to a heat recovery steam generator(36). The heat from the exhaust(34) is used to produce high pressure steam(38), which is connected to steam turbine(14) of the existing power plant(10), where it is used to produce electricity in a method well known in the art.
As explained above, steam turbine(14) is connected to condenser(20), in which steam (13) and high pressure steam(38) are condensed to hot water, typically known as condensate(24). The condensate(24) is connected to make-up water(26) which replaces water lost due to evaporation and leakage. Combined condensate(24) and Make-up water(26) are connected to boiler(12).
Condensate(24) is also connected to make-up water (42). Make-up water(42) and condensate(24) are connected to the heat recovery steam generator(36).
STATEMENT OF OPERATION
In operation of the original prior art plant, the existing fuels (11) are burned in the boiler (12) to heat the condensate (24) to steam (13). The steam (13) is then injected into a steam turbine (14) causing the steam turbine shaft (not shown) to turn. The steam turbine shaft is connected to an electrical generator (16) to produce electricity. The electricity is then exported to the consumer typically using a grid (18). After passing over the steam turbine shaft, the injected steam (13) is then condensed by the condenser (20) into hot water, typically called condensate (24). Make up water (26) is added to the condensate (24) to compensate for evaporation and leakage throughout the system. The condensate (24) is then pumped (not shown) into the boiler (12) to complete the cycle. This describes the normal, unmodified power plant.
When modified according to the invention the second power plant (28), which is erected beside the existing power plant(10), will include a natural gas fired gas turbine (30).
The gas turbine(30) is of conventional construction, similar in many respects to an aircraft jet engine. Air is inducted and compressed by intake fans. Natural gas (32) is injected into the compressed air and ignited. The combustion products, or exhaust(34), then pass through sets of turbine blades mounted on a central turbine shaft (not shown). All of this is well known and requires no illustration.
The combustion of the gas and compressed air create a high pressure/high temperature exhaust of combusted products, and are passed from the gas turbine (30) to the heat recovery steam generator (36) to heat the condensate (24) producing high pressure steam (38) and low pressure steam/hot water (40). Make -up water(42) is added to the condensate(24) to compensate for evaporation and leakage.
The gas turbine (30) turns the gas turbine shaft (not shown), which is connected to the electrical generator (33), causing the electrical generator (33) to produce electricity. The electricity is then exported to the consumer typically using a grid (18).
The high pressure steam (38) is the injected into the steam turbine (14) of the existing power plant (10) producing electricity. The imported high pressure steam (38) combined with steam (13), which is produced by the boiler (12), cause the steam turbine shaft (not shown) to turn. The steam turbine shaft is connected to an electrical generator (16) to produce electricity. The electricity is then exported to the consumer typically using a grid (18).
After passing over the steam turbine shaft, the combined steam is then condensed into hot water, typically called condensate (24), by the condenser (20). A
portion of s the condensate (24) is returned to second power plant(28). Make up water (42) is added to the condensate (24) to compensate for evaporation and leakage. The condensate is then pumped into the heat recovery steam generator (36) completing the cycle.
The balance of the condensate (24), remaining in the existing power plant (10) is combined with the low pressure steam/hot water (40) thus increasing the amount and temperature of the condensate. Alternatively, the low pressure steam/hot water (40) could heat up the condensate (24) by the use of heat exchangers (not shown). Make up water (26) is added to the condensate (24) to compensate for evaporation and leakage throughout the system. The condensate (24) is then pumped (not shown) into the boiler (12) to complete the cycle.
The utilization of both the imported steam (38) and the low pressure steam/hot water (40) would significantly reduce the consumption amount of the existing fuels.
In the style of the existing plant(10) of Figure 1., in some cases it may be possible to dispense with the use of the existing boiler(12), and to discontinue use of existing fuel(11 ).
The foregoing is a description of a preferred embodiment of the invention which is given here by way of example only. The invention is not to be taken as limited to any of the specific features as described, but comprehends all such variations thereof as come within the scope of the appended claims.
Condensate(24) is also connected to make-up water (42). Make-up water(42) and condensate(24) are connected to the heat recovery steam generator(36).
STATEMENT OF OPERATION
In operation of the original prior art plant, the existing fuels (11) are burned in the boiler (12) to heat the condensate (24) to steam (13). The steam (13) is then injected into a steam turbine (14) causing the steam turbine shaft (not shown) to turn. The steam turbine shaft is connected to an electrical generator (16) to produce electricity. The electricity is then exported to the consumer typically using a grid (18). After passing over the steam turbine shaft, the injected steam (13) is then condensed by the condenser (20) into hot water, typically called condensate (24). Make up water (26) is added to the condensate (24) to compensate for evaporation and leakage throughout the system. The condensate (24) is then pumped (not shown) into the boiler (12) to complete the cycle. This describes the normal, unmodified power plant.
When modified according to the invention the second power plant (28), which is erected beside the existing power plant(10), will include a natural gas fired gas turbine (30).
The gas turbine(30) is of conventional construction, similar in many respects to an aircraft jet engine. Air is inducted and compressed by intake fans. Natural gas (32) is injected into the compressed air and ignited. The combustion products, or exhaust(34), then pass through sets of turbine blades mounted on a central turbine shaft (not shown). All of this is well known and requires no illustration.
The combustion of the gas and compressed air create a high pressure/high temperature exhaust of combusted products, and are passed from the gas turbine (30) to the heat recovery steam generator (36) to heat the condensate (24) producing high pressure steam (38) and low pressure steam/hot water (40). Make -up water(42) is added to the condensate(24) to compensate for evaporation and leakage.
The gas turbine (30) turns the gas turbine shaft (not shown), which is connected to the electrical generator (33), causing the electrical generator (33) to produce electricity. The electricity is then exported to the consumer typically using a grid (18).
The high pressure steam (38) is the injected into the steam turbine (14) of the existing power plant (10) producing electricity. The imported high pressure steam (38) combined with steam (13), which is produced by the boiler (12), cause the steam turbine shaft (not shown) to turn. The steam turbine shaft is connected to an electrical generator (16) to produce electricity. The electricity is then exported to the consumer typically using a grid (18).
After passing over the steam turbine shaft, the combined steam is then condensed into hot water, typically called condensate (24), by the condenser (20). A
portion of s the condensate (24) is returned to second power plant(28). Make up water (42) is added to the condensate (24) to compensate for evaporation and leakage. The condensate is then pumped into the heat recovery steam generator (36) completing the cycle.
The balance of the condensate (24), remaining in the existing power plant (10) is combined with the low pressure steam/hot water (40) thus increasing the amount and temperature of the condensate. Alternatively, the low pressure steam/hot water (40) could heat up the condensate (24) by the use of heat exchangers (not shown). Make up water (26) is added to the condensate (24) to compensate for evaporation and leakage throughout the system. The condensate (24) is then pumped (not shown) into the boiler (12) to complete the cycle.
The utilization of both the imported steam (38) and the low pressure steam/hot water (40) would significantly reduce the consumption amount of the existing fuels.
In the style of the existing plant(10) of Figure 1., in some cases it may be possible to dispense with the use of the existing boiler(12), and to discontinue use of existing fuel(11 ).
The foregoing is a description of a preferred embodiment of the invention which is given here by way of example only. The invention is not to be taken as limited to any of the specific features as described, but comprehends all such variations thereof as come within the scope of the appended claims.
Claims (16)
1. The method of converting an existing thermal fuel electrical generating station having at least one existing steam turbine and at least one existing electrical generator, and at least one existing boiler using existing fuels , to use a combination of existing fuels and natural gas, thereby reducing said existing fuel consumption while retaining said existing at least one steam turbine and said at least one existing electrical generator of said existing thermal fuel electrical generating station and comprising the steps of;
erecting at least one gas turbine prime mover alongside the existing thermal fuel electrical generating station, said at least one gas turbine prime mover producing exhaust gases;
connecting said at least one gas turbine prime mover to at least one natural gas electrical generator;
connecting said exhaust gases from said at least one gas turbine prime mover to at least one heat recovery steam generator;
connecting said at least one heat recovery steam generator to said at least one existing steam turbine of the existing thermal fuel electrical generating station;
operating said at least one existing steam turbine in said existing thermal fuel electrical generating station to cause said at least one existing electric generator of said existing thermal fuel electrical generating station to generate a first supply of electricity and supplying said first supply of electricity to a grid;
operating said at least one gas turbine prime mover to cause said at least one natural gas electrical generator to generate a second supply of electricity, and supplying said second supply of electricity to a grid; and, exporting steam from said at least one heat recovery steam generator to said existing thermal fuel electrical generating station, thereby reducing said existing fuel consumption of said at least one existing steam turbine in the existing thermal fuel electrical generating station.
erecting at least one gas turbine prime mover alongside the existing thermal fuel electrical generating station, said at least one gas turbine prime mover producing exhaust gases;
connecting said at least one gas turbine prime mover to at least one natural gas electrical generator;
connecting said exhaust gases from said at least one gas turbine prime mover to at least one heat recovery steam generator;
connecting said at least one heat recovery steam generator to said at least one existing steam turbine of the existing thermal fuel electrical generating station;
operating said at least one existing steam turbine in said existing thermal fuel electrical generating station to cause said at least one existing electric generator of said existing thermal fuel electrical generating station to generate a first supply of electricity and supplying said first supply of electricity to a grid;
operating said at least one gas turbine prime mover to cause said at least one natural gas electrical generator to generate a second supply of electricity, and supplying said second supply of electricity to a grid; and, exporting steam from said at least one heat recovery steam generator to said existing thermal fuel electrical generating station, thereby reducing said existing fuel consumption of said at least one existing steam turbine in the existing thermal fuel electrical generating station.
2. The method of converting an existing thermal fuel electrical generating station, as claimed in Claim 1, and further comprising the steps of generating high pressure steam in said at least one heat recovery steam generator, and generating low pressure steam in said at least one heat recovery steam generator, and exporting both said high pressure and low pressure steam to said existing thermal fuel electrical generating station, said high pressure steam going to said steam turbine and said low pressure steam going to said boiler.
3. The method of converting an existing thermal fuel electrical generating station, as claimed in Claim 2, and further comprising the steps of, condensing combined steam from said existing thermal fuel electrical generating station and returning it back to said at least one heat recovery steam generator, thereby recycling calorific values of said combined steam.
4. The method of converting an existing thermal fuel electrical generating station, as claimed in Claim 3, and further comprising the steps of directing condensate partly to said at least one heat recovery steam generator and partly to said existing boiler.
5. The method of converting an existing thermal fuel electrical generating station, as claimed in Claim 4, and further comprising the steps of operating said at least one gas turbine prime mover by continuous introduction of air, compressing the air, introducing gas into said compressed air, and igniting the gas and compressed air to create a high pressure exhaust of combustion products, from said at least one gas turbine prime mover, and conducting said exhaust combustion products to said at least one heat recovery steam generator for recycling of heat value therefrom.
6. The method of converting an existing thermal fuel electrical generating station, as claimed in Claim 5, and further comprising the steps of introducing feed water to said at least one heat recovery steam generator, and preheating said feed water with condensate from said at least one steam turbine.
7. The method of converting an existing thermal fuel electrical generating station, from existing fuels to natural gas, whereby eliminating the existing fuel consumption while retaining at least one existing steam turbine and at least one existing electrical generator of the existing station and comprising the steps of;
erecting at least one gas turbine prime mover alongside the existing thermal fuel electrical generating station, said at least one gas turbine prime mover producing exhaust gases;
connecting said at least one gas turbine prime mover to at least one natural gas electrical generator;
connecting at least one heat recovery steam generator to receive hot exhaust gases from said natural gas turbine and generating steam for said at least one steam turbine of the existing thermal fuel electrical generating station;
operating said at least one gas turbine prime mover to cause the at least one natural gas electrical generator to generate a natural gas supply of electricity, and supplying said natural gas supply of electricity to a grid;
exporting steam from said at least one heat recovery steam generator to said steam turbine; and, operating said at least one steam turbine in said existing thermal fuel electrical generating station by steam from said at least one heat recovery steam generator to cause said at least one existing electric generator of said existing thermal fuel electrical generating station to generate a supplementary supply of electricity and supplying said supplementary supply of electricity to a grid, without use of said existing fuel, thereby eliminating said existing fuel consumption of said at least one existing steam turbine in the existing thermal fuel electrical generating station.
erecting at least one gas turbine prime mover alongside the existing thermal fuel electrical generating station, said at least one gas turbine prime mover producing exhaust gases;
connecting said at least one gas turbine prime mover to at least one natural gas electrical generator;
connecting at least one heat recovery steam generator to receive hot exhaust gases from said natural gas turbine and generating steam for said at least one steam turbine of the existing thermal fuel electrical generating station;
operating said at least one gas turbine prime mover to cause the at least one natural gas electrical generator to generate a natural gas supply of electricity, and supplying said natural gas supply of electricity to a grid;
exporting steam from said at least one heat recovery steam generator to said steam turbine; and, operating said at least one steam turbine in said existing thermal fuel electrical generating station by steam from said at least one heat recovery steam generator to cause said at least one existing electric generator of said existing thermal fuel electrical generating station to generate a supplementary supply of electricity and supplying said supplementary supply of electricity to a grid, without use of said existing fuel, thereby eliminating said existing fuel consumption of said at least one existing steam turbine in the existing thermal fuel electrical generating station.
8. The method of converting an existing thermal fuel electrical generating station, as claimed in Claim 7, and further comprising the steps of, condensing combined steam from said at least one steam turbine and returning it back to said at least one heat recovery steam generator, thereby recycling calorific values of said combined steam.
9. The method of converting an existing thermal fuel electrical generating station, as claimed in Claim 8, and further comprising the steps of operating said at least one gas turbine prime mover by continuous introduction of air, compressing the air, introducing gas into said compressed air, and igniting the gas and compressed air to create a high pressure exhaust of combustion products, from said at least one gas turbine prime mover, and conducting said exhaust combustion products to said at least one heat recovery steam generator for recycling of heat value therefrom.
10. The method of converting an existing thermal fuel electrical generating station, as claimed in Claim 9, and further comprising the steps of introducing feed water to said at least one heat recovery steam generator, and preheating said feed water with condensate from said at least one existing steam turbine.
11. Apparatus for converting an existing thermal fuel electrical generating station, to use a combination of existing fuels and natural gas, while retaining the at least one existing steam turbine, at least one boiler and at least one existing electrical generator of said existing thermal fuel electrical generating station and comprising ;
erecting at least one gas turbine prime mover erected adjacent said existing thermal fuel electrical generating station;
at least one gas turbine powered electrical generator, connected to said at least one gas turbine , and which is in turn connected to a supply power to a grid;
at least one heat recovery steam generator connected to the exhaust of said at least one gas turbine prime mover to generate steam; and, at least one steam connection between said at least one heat recovery steam generator, and said at least one existing steam turbine in the existing thermal fuel electrical generating station, whereby said converted thermal fuel electrical generating station is operable to generate a first electrical supply from said at least one existing electrical generator, and to generate a second electrical supply from said at least one gas turbine powered generator.
erecting at least one gas turbine prime mover erected adjacent said existing thermal fuel electrical generating station;
at least one gas turbine powered electrical generator, connected to said at least one gas turbine , and which is in turn connected to a supply power to a grid;
at least one heat recovery steam generator connected to the exhaust of said at least one gas turbine prime mover to generate steam; and, at least one steam connection between said at least one heat recovery steam generator, and said at least one existing steam turbine in the existing thermal fuel electrical generating station, whereby said converted thermal fuel electrical generating station is operable to generate a first electrical supply from said at least one existing electrical generator, and to generate a second electrical supply from said at least one gas turbine powered generator.
12. Apparatus for converting an existing thermal fuel electrical generating station, as claimed in Claim 11, and including at least one steam condenser connected to said at least one steam turbine and connected back to said at least one heat recovery steam generator.
13. Apparatus for converting an existing thermal fuel electrical generating station, as claimed in Claim 12, and including at least one feed water supply connected to said at least one heat recovery steam generator, and a heat exchanger connected between said feed water supply and said steam condenser, for preheating said feed water.
14. Apparatus for converting an existing thermal fuel electrical generating station, from existing fuels to natural gas, thereby eliminating the existing fuel consumption while retaining the existing at least one steam turbine and at least one existing electrical generator of said existing thermal fuel electrical generating station and comprising;
at least one gas turbine prime mover erected adjacent said existing thermal fuel electrical generating station;
at least one gas turbine powered electrical generator, connected to said at least one gas turbine , and which is in turn connected to a supply power to a grid;
at least one heat recovery steam generator connected to the exhaust of said at least one gas turbine prime mover to generate steam; and, at least one steam connection between said at least one heat recovery steam generator, and said at least one existing steam turbine in the existing thermal fuel electrical generating station, whereby said converted thermal fuel electrical generating station is operable to generate a first electrical supply from said at least one existing electrical generator, and to generate a second electrical supply from said at least one gas turbine powered generator.
at least one gas turbine prime mover erected adjacent said existing thermal fuel electrical generating station;
at least one gas turbine powered electrical generator, connected to said at least one gas turbine , and which is in turn connected to a supply power to a grid;
at least one heat recovery steam generator connected to the exhaust of said at least one gas turbine prime mover to generate steam; and, at least one steam connection between said at least one heat recovery steam generator, and said at least one existing steam turbine in the existing thermal fuel electrical generating station, whereby said converted thermal fuel electrical generating station is operable to generate a first electrical supply from said at least one existing electrical generator, and to generate a second electrical supply from said at least one gas turbine powered generator.
15. Apparatus for converting an existing thermal fuel electrical generating station, as claimed in Claim 14, and including at least one steam condenser connected to said at least one steam turbine and connected back to said at least one heat recovery steam generator.
16. Apparatus for converting an existing thermal fuel electrical generating station, as claimed in Claim 15, and including at least one feed water supply connected to said at least one heat recovery steam generator, and a heat exchanger connected between said feed water supply and said steam condenser, for preheating said feed water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2352474 CA2352474C (en) | 2001-07-25 | 2001-07-25 | Retrofit system for electrical power generating stations and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA 2352474 CA2352474C (en) | 2001-07-25 | 2001-07-25 | Retrofit system for electrical power generating stations and method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2352474A1 CA2352474A1 (en) | 2001-10-21 |
| CA2352474C true CA2352474C (en) | 2002-07-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2352474 Expired - Fee Related CA2352474C (en) | 2001-07-25 | 2001-07-25 | Retrofit system for electrical power generating stations and method |
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| Country | Link |
|---|---|
| CA (1) | CA2352474C (en) |
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2001
- 2001-07-25 CA CA 2352474 patent/CA2352474C/en not_active Expired - Fee Related
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| Publication number | Publication date |
|---|---|
| CA2352474A1 (en) | 2001-10-21 |
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