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Publication numberUS3796045 A
Publication typeGrant
Publication dateMar 12, 1974
Filing dateJul 15, 1971
Priority dateJul 15, 1971
Publication numberUS 3796045 A, US 3796045A, US-A-3796045, US3796045 A, US3796045A
InventorsFoster Pegg R
Original AssigneeTurbo Dev Inc
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Method and apparatus for increasing power output and/or thermal efficiency of a gas turbine power plant
US 3796045 A
Abstract
A gas turbine power plant having a modified gas turbine cycle (Brayton cycle) wherein the compressor inlet air is super-chilled before it enters the compressor. Superchilling, as defined herein, means to supercharge the inlet air to increase the pressure thereof to a pressure level moderately greater than the atmospheric pressure and to chill the supercharged air to decrease the temperature thereof, the preferred temperature level being in the vicinity of about 40 DEG Fahrenheit. A heat recovery cycle is provided to supply the energy necessary to superchill the compressor inlet air.
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Description  (OCR text may contain errors)

United States Patent F oster-Pegg Mar. 12, 1974 [5 METHOD AND APPARATUS FOR 3,500,636 3/1970 Craig 60/39.]8 B X INCREASING POWER OUTPUT AND/OR FOREIGN PATENTS OR APPLICATIONS THERMAL EFFICIENCY OF A GAS URBINE POWER PLANT 505,044 8 1954 Canada 60/39.18 B T 679,007 9/1952 Great Britain 60/3918 B [75] Inventor: Richard W. Foster-Pegg, Warren,

Primary Examiner-A1 Lawrence Smith [73] Assignee: Turbo-Development, Inc., New Assistant Exammer Mlchael K0020 York, Attorney, Agent, or F1rml(enyon and Kenyon Rellly Carr and Chapin [22] Filed: July 15, 1971 [21] App]. No.: 162,911 57 ABSTRACT A gas turbine power plant having a modified gas tur- [52] US. Cl 60/39.02, 60/3918 B, 60/39.67 i Cycle (Brayton cycle) wherein the compressor [51] Int. Cl F02c 3/06, F020 7/10 inlet air is supepchilled b f it enters the commas- [58] Fleld of Search 60/39'18 R, 39-18 39-18 sor. Superchilling, as defined herein, means to super- 60/39-18 C1 39-67; 415/179 v charge the inlet air to increase the pressure thereof to a pressure level moderately greater than the atmo- 1 I References Clted spheric pressure and to chill the supercharged air to UNITED STATES PATENTS decrease the temperature thereof, the preferred tem- 3,631,673 1/1972 Charrier 60/39.18 c Peratufe level being in h vicinity Of about Fahr- 2,663,144 12/1953 Nordstrom et a1. 1. 60/39.18 B enheit. A heat recovery cycle is provided to supply the 2,633,707 4/1953 Hermitte etal. 60/39.18 B X energy necessary to superchill the compressor inlet 2,322,717 6/1943 air. 3,479,541 11/1969 3,153,442 10/1964 Silvern 62/467 UX 6 Claims, 9 Drawing Figures Vase/Var 30/454 Facade/mu: f/ex r cvmesssoe PATENTEB m 12 m4 SHEET 8 OF 8 KEQQ W lk 8v? EMA/86$ V Army/yam PATENTEBm 12 1914 SHEEI 7 OF 8 wav 4 P/vas PATENTEI] IIAR 1 2 I974 sum 3 or 8"" METHOD AND APPARATUS FOR INCREASING POWER OUTPUT AND/OR THERMAL EFFICIENCY OF A GAS TURBINE POWER PLANT BACKGROUND OF THE INVENTION The present invention broadly relates to a modified gas turbine cycle for a gas turbine power plant. More particularly, the invention relates to a modified gas turbine cycle wherein the compressor inlet air is superchilled to increase the power output and/or the thermal efficiency of the gas turbine power plant.

Gas turbine power plants have been used for many years to generate electrical power, particularly during periods when demand for electrical power is greatest. The peak demand periods generally occur during the hottest weather when the ambient temperature of the air is high. The high temperature of the compressor inlet air at these times significantly reduces the performance of a gas turbine power plant by decreasing the power output and/or thermal efficiency of the turbine. Consequently, during periods of more moderate or normal ambient air temperatures, the power required of the stationary gas turbine may be substantiallybelow that which the turbine is capable of producing at these conditions so that adequate capacity is available when the ambient'temperature of the air is high.

Electrical utilities and gas turbine manufacturers have considerable incentives to increase the power output and/or thermal efficiency of stationary gas turbine power plants, and much effort has been expended to reap the rewards occasioned by each increase therein. Thus, stationary gas turbine power plants occasionally include various means for modifying the basic gas turbine cycle such as intercoolers, regenerators and recuperators which increase the power output and/or thermal efficiency of the gas turbine power plant. In. addition, limited use has been made of supercharging the compressor inlet air and cooling the supercharged air to increase the power output of the gas turbine power plant. However, at the present time such uses extend only to supercharging with electric motor driven fans and to cooling with evaporative coolers. For example, see Foster-Pegg, R.W., supercharging of Gas Turbines by Forced Draft Fans with Evaporative Intercooling," American Society of Mechanical Engineers, Paper No. 65-GTP 8 (1965). Thus, the prior art does not disclose supercharging compressor inlet air with waste heat energy from the gas turbine exhaust gases. Further, chilling the compressor inlet air to low tem peratures is also known. For example, see US. Pat. No. 2,322,717 for Apparatus For Combustion Turbines issued June 22, 1943. However, chilling of the compressor inlet air has not been adopted by electrical utilities and gas turbine manufacturers, except when a means for chilling the intake air is already available or is being installed for another purpose.

At present, no gas turbine power plant has been installed with a chilling means provided for the primary purpose of chilling the compressor inlet-air. Thus, the prior art does not disclose chilling the compressor inlet air with a refrigeration system having a compressor driven by waste-heat energy from the exhaust gases of the gas turbine. Further, the prior art does not include supercharging and chilling the compressor inlet air.

Despite the incentives to increase the power output and/or thermal efficiency of gas turbine power plants and the efforts that have been expended in this regard, present gas turbine power plants generally remain uneconomical for continuous base load electrical power generation when compared to steam turbine power plants or combined steam and gas turbine power plants.

SUMMARY OF THE INVENTION A gas turbine power plant is provided having a basic 7 gas turbine cycle comprising the following steps: compressing the inlet air from the atmosphere in a compressor; heating the compressed air in a combustor; and expanding the heated, compressed air through a turbine.

According to one embodiment of the present invention, the power output and/or the thermal efficiency of the basic gas turbine cycle described above are significantly improved by the additional step of Superchilling the ambient inlet air before it enters the compressor of the gas turbine power plant. Superchilling, as used herein, means supercharging the inlet air to the compressor of the gas turbine to increase the pressure thereof to a pressure level moderately greater than the atmospheric pressure by means of a low pressure ratio device and chilling the supercharged inlet air to reduce the temperature thereof to a temperature at least as low as the temperature that could be obtained with an evaporative cooler cooling the supercharged air under ambient conditions then present. Chilling is accomplished by the direct transfer of heat from the supercharged inlet air to the refrigerant of a refrigeration system.

The term refrigerant is used herein in a broad and not a restriction senseof the word. The term refrigerant includes all fluids (such as liquids, vapors, and gas) to which heat from the inlet air can be transferred to chill the air. Thus, the term refrigerant is not limited to those liquids which produce refrigeration by their evaporation from a liquid to a gaseous under reduced pressure. By way of example, the term refrigerant can include liquid, such as a brine, which serves as an intermediate refrigerant between a primary refrigerant used to cool the fluid and the inlet air which is chilled by the direct transfer of heat to the fluid. F urther, the term refrigerant" includes ice which may be used to chill the inlet air directly or to cool an intermediate refrigerant such as a brine.

The compressor inlet air is preferably supercharged to increase the pressure thereof in accordance with a supercharging pressure ratio in the range of pressure ratios extending from about 1.1 to about 1.75. One preferred low pressure ratio device for increasing the pressure of the compressor inlet air is a fan device, for example, a conventional single stage, dual flow centrifugal blower. Supercharging pressure ratios above those obtainable with a single stage fan device can be obtained by two stages of supercharging with such a fan device.

Generally speaking, since ambient air usually contains some moisture, the lower temperature limit for the chilling of the supercharged gas is a temperature in the vicinity of the temperature at which concomitant chilling of the moisture in the inlet air could form ice accumulations on heat transfer surfaces used to chill the inlet air. To avoid ice accumulations, the temperature of a heat transfer surface used to chill the inlet air should be maintained at a temperature at least as high as the freezing temperature of the moisture in the inlet air. Thus, as the chilling temperature level of the inlet air approaches the freezing temperature of the moisture in the inlet air, an extensive heat transfer surface is required to chill the air. Accordingly, a chilling temperature level in the vicinity of the range of temperatures extending from about 35 degrees Fahrenheit to about 40 Fahrenheit is preferred.

However, lower chilling temperatures are possible. For example, a means for removing the ice formed on the heat transfer surfaces can be provided thus enabling the compressor inlet air to be chilled to a temperature significantly below the preferred range of temperatures. Further, if a significant degree of moisture is not present in the compressor inlet air, the chilling temperature can also extend considerablybelow the preferred range of temperatures.

The energy required to chill the inlet air is increased by moisture contained in the air. Since the supercharged inlet air is generally chilled to a temperature below the dew point of the inlet air, moisture in the inlet air in excess of the saturated moisture content of the air at the chilling temperature will be condensed in the chilling means. Accordingly, under humid conditions, the total cooling requirement for the chilling means significantly exceeds the sensible heat cooling that would be required for dry air alone.

The compressor inlet air can be chilled both before and after the inlet air has been supercharged, or the inlet air can be chilled only after it has been supercharged. Although chilling both before and after supercharging can result in increased capital expenditures, it can be advantageous under certain circumstances. Initial chilling of the inlet air reduces the power required to supercharge a given inlet air mass flow rate, and thus reduces the total power required to chill the inlet air before it enters the compressor since the heat input to the inlet air caused by supercharging is reduced. The reduction of power to supercharge the inlet air results from the lower temperature of the air entering the supercharging means and from the decreased mass flow rate through the supercharging means caused by the moisture condensed from the inlet air during the initial chilling thereof. Further, the reduced power required to charge the inlet air to a given pressure permits a higher supercharge pressure to be obtained when a heat recovery cycle, to be discussed hereinafter, is provided to drive the supercharging means and the chilling means.

According to another embodiment of the present invention, a heat recovery cycle is provided to supply the energy necessary to superchill the compressor inlet air. For example, a waste-heat boiler can be provided to generate steam by utilizing the waste-heat in the turbine exhaust gases. The steam is subsequently expanded through a first and a second steam turbine. The output shaft of the first steam turbine is coupled to drive the low pressure ratio device for supercharging the compressor inlet air. The output shaft of the second steam turbine is coupled to drive a compression refrigeration unit for chilling the compressor inlet air.

As will be more fully illustrated below, significant and heretofore unforeseen benefits result from superchilling the compressor inlet air. Superchilling the compressor inlet air significantly increases the air mass flow rate to the compressor of the gas turbine power plant at a fixed volume flow rate by increasing the pressure and decreasing the temperature of the inlet air. Superchilling also increases the gas turbine inlet pressure thereby increasing the expansion ratio across the gas turbine. The increased air mass flow rate through the gas turbine power plant and the increased expansion ratio across the turbine provide a significant increase in the poweroutput of the gas turbine power plant. F urther, the lower compressor inlet air temperature permits the gas turbine power plant to be operated at near optimum power output irrespective of the ambient air temperature. When the heat recoverycycle is provided to superchill the compressor inlet air, an additional significant increase in the power, output results as well as an improvement in the thermal efficiency of the gas turbine.

Accordingly, it is an objective of the present invention to provide a gas turbine power plant having increased power output and/or thermal efficiency.

Another object is to increase the power output and- /or the thermal efficiency of the gas r turbine power plant when the ambient temperature of the air is high.

Still another object is to provide a gas turbine power plant wherein ambient inlet air is superchilled before it enters the compressor of the gas turbine for increasing the power output and/or the thermal efficiency of the turbine cycle.

A further object is to provide a gas turbine power plant wherein waste-heat in the turbine exhaust gases is utilized to supply the energy for superchilling the compressor inlet air.

A still further object is to provide a gas turbine power plant for driving an electric generator wherein the compressor inlet air is superchilled before it enters the compressor, and the electric generator cooling medium is chilled for simultaneously increasing the power output and/or the thermal efficiency of the gas turbine and the generating capacity of the electric generator.

A still further object is to provide a gas turbine power plant wherein the waste-heat in the turbine exhaust gases is utilized to supply the energy for superchilling the compressor inlet air and for chilling the electric generator cooling medium.

These and other objects and advantages of the gas turbine power plant of the present invention will become more apparent from the following description, when read in conjunction with the accompanying drawings, wherein corresponding parts of each figure have corresponding numbers.

FIG. '1 is a schematic diagram of one embodiment of the present invention wherein the compressor inlet air is supercharged and subsequently chilled before the air enters the compression stage of the gas turbine.

FIG. 2 is a schematic diagram of another embodiment of the present invention wherein the supercharger and chiller are driven by waste-heat energy recovered from the turbine exhaust gases.

FIG. 3 is a schematic diagram of still another embodiment of the present invention showing selected operating characteristics for a complete gas turbine cycle adjacent the individual components.

FIG. 4 is a graph showing the power output of the embodiment of the gas turbine power plant illustrated in FIG. 3 as a function of the degree of superchilling of the compressor inlet air.

FIG. 5 is a graph showing the heat rate of the embodiment of the gas turbine power plant illustrated in FIG. 3 as a function of the degree of superchilling of the compressor inlet air.

FIG. 6 is a schematic diagram of the embodiment of the gas turbine power plant of FIG. 2 showing selected operating characteristics for a complete gas turbine cycle adjacent the individual components.

FIG. 7 is a schematic diagram of still another embodiment of the present invention wherein the compressor inlet air is chilled before and after it is supercharged.

FIG. 8 is a schematic diagram of the embodiment of the gas turbine power plant illustrated in FIG. 2 showing a second set of selected operating characteristics for a complete gas turbine cycle adjacent the individual components.

FIG. 9 is a schematic diagram of still another embodiment of the present invention showing selected operating characteristics for a complete gas turbine cycle adjacent the individual components.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, one preferred embodiment of the improved gas turbine power plant is schematically illustrated in FIG. 1. The improvement of the present invention is schematically shown in conjunction with-a conventional open-cycle, single shaft gas turbine power plant. The gas turbine power plant comprises a compressor 10 for compressing the inlet air from the atmosphere, a combustor 11 for heating the compressed air, and a turbine 12 for expanding the heated, compressed air. The turbine 12 is operably coupled to drive the compressor 10 and an electric generator 13 by means of shaft 14.

According to the present invention, the power output and/or the thermal efficiency of the gas turbine described above are significantly increased by superchilling the inlet air before it enters the compressor of the gas turbine.

Thus, referring to FIG. 1, a supercharging means 15 is provided which comprises a low pressure ratio device, conveniently shown as a fan 16, driven by an electric motor 17. Inlet air is drawn through the fan 16 thereby increasing the pressure thereof to a pressure level moderately greater than the atmospheric pressure. Once the inlet air has been supercharged, it is ducted to a chilling means 18.

The chilling means 18 is conveniently shown as a compression refrigeration unit 19 which comprises an evaporator coil 20 in which a liquid refrigerant boils at a low temperature, a compressor 21 driven by an electric motor 22 for raising the pressure and temperature of the gaseous refrigerant from the evaporator coil 20, a condenser 23 in which the refrigerant from the compressor 21 discharges heat to a secondary cooling medium such as water, and an expansion valve 24 for expanding the liquid refrigerant from the high pressure level in the condenser 21 to the low pressure level in the evaporator coil 20. The supercharged inlet air is ducted across the evaporator coil 20 where the air is chilled as heat from the air is transferred to the expanded gaseous refrigerant therein.

The secondary cooling medium is circulated through the coil 25 of the condenser 23 by a circulating pump 26 where the gaseous refrigerant condenses to a liquid and releases heat to the cooling medium. The cooling medium subsequently circulates through a cooling coil 27 of a cooling tower 28 where the cooling medium discharges heat to air circulated across the cooling coil 27 by a cooling fan 29, driven by an electric motor 30.

To illustrate the increased performance of a gas turbine power plant obtained by superchilling the compressor inlet air, the power output and thermal efficiency of various embodiments of the gas turbine power plant are described below. The ideal gas turbine power plant assumed for some of the comparisonsis a 25 megawatt gas turbine power plant having an ideal gas turbine cycle (Brayton Cycle) rated at a compressor inlet temperature of about F. and a compressor inlet pressure of about 392 inches of water which corresponds to the pressure at about a 1,000 foot elevation. The ideal cycle has no inlet or exhaust pressure losses. Assuming a compressorinlet mass flow rate of about 1 X 10 pounds of air per hour, a combustor fuel requirement of about 300 X 10 Btu/Hr LI-IV (Lower Heating Value), and a gas turbine exhaust temperature and pressure of about 895F. and about 392 inches of water, respectively, the ideal gas turbine power plant would produce about 25 megawatts (rated power output) at a heat rate of about 12,000 Btu/Kwh LI-IV.

The performance of the ideal 25 megawatt gas turbine power plant is significantly reduced when the gas turbine is operated under warm weather conditions. If the ideal gas turbine were operated at high ambient inlet air temperatures of about F. dry bulb and 80F. wet bulb at about a 1,000 foot elevation with an inlet pressure loss of about 2 inches of water and an exhaust pressure loss of about 4 inches of water, the ideal gas turbine would produce about 87.5 per cent of the rated power output (21.6 megawatts) at a heat rate of about 13,000 Btu/Kwh LI-IV. The power output and heat rate calculations are based upon a compressor mass flow rate of about 0.954 X 10 pounds of air per hour, a combustor fuel requirement of about 281.7 X 10 Btu/hr Ll-IV, and a turbine exhaust pressure of about 396 inches of water. The ideal 25 megawatt gas turbine having the above assumed inlet and exhaust pressure losses will hereinafter be referred to as the standard gas turbine.

Superchilling the compressor inlet air of the standard gas turbine described above, as shown in FIG. 1, significantly increases the power output and/or thermal efficiency of the gas turbine. For example, assume the following operating conditions: inlet air temperatures, pressure and mass flow rates of about 100F. dry bulb,

about 80F. wet bulb, about 390 inches of water, about 1.223 X 10 pounds of air per hour and about 21.4 x 10 pounds of water per hour; a combustor fuel requirement of about 382.3 X 10 Btu/hr LI-IV; and a turbine exhaust temperature of about 823F. Supercharg ing the compressor inlet air of the standard gas turbine to moderately raise the pressure thereof from about 390 inches of water to about 448 inches of water with a motor driven fan 16, and chilling the supercharged compressor inlet air to about 40F. with a motor driven compression refrigeration unit 19 increases the net power output of the standard gas turbine to about 125 per cent of rated power output (31.17 megawatts) at a heat rate of about 12,300 Btu/Kwh Ll-IV. The motor driven fan 16 would require about 2,750 kilowatts to supercharge the inlet air. The refrigeration unit 19 would require about 3,892 kilowatts to chill the supercharged air. Thus, of the about 37.8 megawatts of electrical power generated by the standard gas turbine, about 6,642 kilowatts are consumed by the superchilling thereby providing a net power output of about 31.17 megawatts.

Another preferred embodiment of' the present invention is schematically illustrated in FIG. 2. As described above, the supercharging means 15 and the chilling means 18 of the present invention are shown in conjunction with a conventional open cycle, single shaft gas turbine power plant. However, in FIG. 2, the compressedair from the compressor is heated in a regenerator'by waste heat in the turbine exhaust gases. Thus, the compressed air is ducted through the coil 35 of a regenerative heat exchanger 36 before it enters the combustor 11. Most of the turbine exhaust gas is ducted across the heat exchanger coil 35 for heating the compressed air passing therethrough.

According to the present invention, the power output and/or thermal efficiency of the gas turbine power plant are still more significantly increased by the addition of a heat recovery cycle wherein residual wasteheat in the turbine exhaust gases is recovered and converted into mechanical energy for driving the supercharging means and the chilling means 18. Thus, referring to FIG. 2, a closed steam cycle is provided wherein a waste-heat boiler 37 generates steam from the residual waste-heat in the turbine exhaust gases. The steam generated thereby is expanded through a first steam turbine 38, operably coupled to drive the supercharging means 15, and a second steam turbine 39, operably coupled to drive the chilling means 18.

The turbine exhaust gases from the regenerative heat exchanger 36 are ducted through the waste-heat boiler 37. The residual waste-heat in the exhaust gas generates steam from water pumped through the coils 40- of the waste-heat boiler 37. The steam generated thereby is subsequently circulated through the coil 41 of a steam heat exchanger 42 where the waste-heat in the remainder of the turbine exhaust gases superheats the steam. The remainder of the exhaust gases is then ducted through the waste-heat boiler 37 to supplement the waste-heating by the turbine exhaust gases from the regenerative heater 36.

A portion of the superheated steam generated by the waste-heat boiler is expanded in'the first steam turbine 38 which is operably coupled to drive the fan 16 of the supercharging means 15. The remainder of the superheated steam is expanded in the second steam turbine 39 which is operably coupled to drive the compressor 21 of the compression cycle refrigeration unit 19. The steam discharged from the steam turbines 38 and 39 is condensed in condensors 43 and 44 and is recycled to the waste-heat boiler 37 by return pumps 45 and 46. The cooling medium for the condensers 43 and 44 is conveniently provided from the secondary cooling medium for the condenser coil 23. Thus, the circulating pump also circulates the cooling medium from the cooling coil 26 through the condenser coil 23 of the refrigeration unit 19 and through the coils 47 and 48 of the condensers 43 and 44.

The performance of the gas turbine power plant is still further improved when the electric generating capacity of the electric generator is increased to complement the increased shaft output of the gas turbine power plant. An electric generator cooling means 50 is provided to chill the generator cooling medium. The cooling means 50 comprises a generator cooling coil 51 disposed within the electric generator 13 in a heattransfer relationship withthe generator cooling circuit 52. The liquid refrigerant from the chilling means 18 is circulates through the coil 51 to substantially chill the generator cooling medium flowing in the circuit 52. As illustrated in FIG. 3, the generator cooling coil 51 and the evaporator coil 20 are connected in parallel between the expansion valve 24 and the compressor 21.

The liquid refrigerant expands through the expansion valve 24 and is circulated through the generator cooling coil 51 where the refrigerant boils to chill the generator cooling medium.

As noted above, superchilling the compressor inlet air according to the present invention significantly increases the power output and/or thermal efficiency of a gas turbine power plant. For example, another embodiment of the present invention is illustrated in FIG. 3. The embodiment of the gas turbine power plant of FIG. 3 is similar to the gas turbine power plant illustrated in FIG. 2, however, the compressed air from the compressor 10 is not regeneratively heated by a regenerative heat exchanger 36.

The operating characteristics of the gas turbine power plant listed in FIG. 3 are calculated on the'basis of a compressor inlet pressure loss of about 2 inches of water and a turbine exhaust pressure loss of about 4 inches of water. An additional inlet pressure loss of about 2 inches of water is assumed for the chilling means 19 and an additional exhaust pressure loss of about 4 inches of water is assumed for the waste heat boiler 37. Thus, the gas turbine of FIG. 3 having the compressor inlet air supercharged to increase the compressor inlet pressure by about 58 inches of water and chilled to reduce the temperature of the compressor inlet air to about 40F. would produce about 15 l per cent of the rated power output (37.8 megawatts) at a heat rate of about 10,130 Btu/Kwh LHV.

Now, referring to FIGS. 4 and 5, the performance of the standard gas turbine power plant described above is compared with the performance of the gas turbine power plant of FIG. 3 under varying levels'of supercharging and chilling. The performances are compared for high ambient inlet air temperatures of about 100F. dry bulb and about F. web bulb at about a 1,000 foot elevation. An inlet pressure loss of about 2 inches of water and an exhaust pressure loss of about 4 inches of water are assumed for the standard gas turbine power plant. An additional inlet pressure loss of about 2 inches of water is assumed for the chilling means and an additional exhaust pressure loss of about 4 inches'of water is assumed for the heat recoverycycle.

The performance of the standard gas turbine power plant is represented in FIGS. 3 and 4 by the points marked A on the F. line (no chilling) corresponding to zero pressure increase (no supercharging). As

indicated therein, the standard gas turbine power plant would produce about 87.5 per cent of the rated powerv output (21.6 megawatts) at a heat rate of about 13,000 Btu/Kwh LI-IV. In comparison, the performance of the gas turbine power plant of FIG. 3 is indicated by the I points marked 8.

The increase in power output and/or thermal efficiency of a gas turbine power plant having superchilled compressor inlet air is still more significant when the gas turbine cycle includes regenerative heating of the compressor outlet air, as shown in FIG. 6.'The embodiment of the present invention illustrated in FIG. 6 is the same as the embodiment illustrated in FIG. 2. Referring to FIG. 6, selected characteristics of the gas turbine power plant for one set of operating conditions are listed adjacent the individual components thereof. The same ambient conditions and pressure losses assumed for the calculations presented in FIGS. 4 and 5 were applied to the calculations for FIG. 6. The power output for the superchilled gas turbine powerplant of FIG. 6 is about 39.6 megawatts at a heat rate about 8,480 Btu/Kwh LHV.

By way of comparison, the power output of a conventional regenerative gas turbine power plant would be about 26.1 megawatts at a heat rate of about 9,850 Btu/Kwh Ll-IV. These calculations are based upon the following conditions: air temperature, pressure and mass flow rates of about 80F., about 388 inches of water, and about 0.96 X 10 pounds of air per hour and about 13.3 X 10 pounds of water per hour, respectively; a compressor compression ratio of about.9.0 and a turbine expansion ratio of about 7.8; a compressor outlet temperature of about 543F., a combustor inlet temperature of about 839F. and a turbine inlet tempe rature of about 1750F.p a combustor fuel requirement of about 257.3 X 10 Btu/Hr LHL; gas turbine exhaust temperature and pressure of about 963F.'and about 404 inches of water, respectively; and regenerator exhaust temperature and pressure of about 743F. and about 396 inches of water, respectively.

As indicated above, the compressor inlet air can also be chilled both before and-after the air is supercharged. An embodiment of the gas turbine power plant having such dual chilling is illustrated in FIG. 7. The chilling means 18 comprises a compression refrigeration unit 19, as described above with respect to FIG. 1, but having a first evaporator coil 20a and a second evaporator coil 20b. The inlet air is initially drawn across the first evaporator coil 20a where the air is chilled as heat from the air is transferred to the coil. The inlet air is next drawn through the fan 16 where the air is supercharged. The supercharged inlet air which has been heated by the work applied to the airby the fan 16 is again chilled as it is ducted across the second evaporator coil 20b before it enters the compressor 10.

Selected characteristics for the gas turbine power plant'for one set of operating conditions are listed in FIG. 7. The power output for the gas turbine is about 42.8 megawatts at a heat rate of about 9,180 Btu/Kwh Ll-IV.

A further example of the significant increase in thermal efficiency and/or power output obtained through superchilling is illustrated in FIG. 8. The embodiment of the gas turbine power plant illustrated therein is similar to the embodiment of FIG. 2; however, the individual components are considerably larger to accommodate the increased air mass flow rate necessary to generate sufficient power to drive the larger generator 13. Although the same pressure losses are assumed for the calculations listed in FIG. 8, it will be noted that the assumed ambient air temperatures are lower than the ambient air temperatures assumed above. At these conditions, the superchilled gas turbine power plant would produce about 77.0 megawatts of power at a heat rate of about 7,060 Btu/Kwh LI-IV.

The heat rate of the superchilled gas turbine power plant of FIG. 8 is remarkably low for a gas turbine power plant and it is highly competitive with the heat rates obtained with steam turbine power plants.

Superchilling the compressor inlet air with energy provided by a heat recovery cycle and regeneratively heating the compressed air before it enters the combustor can utilize substantially all of the waste-heat in the turbine exhaust gases. As a practical matter, maximum regenerator efficiency would commonly be on the order of about seventy-five per cent so that some waste-heat would always be available for the heat recovery cycle. The waste-heat boiler can include an economizer and/or a combination low pressure boiler and deaerator.

Maximum efficiency of superchilling will generally occur at maximum regenerator efficiency with as much of the residual waste-heat leaving the re generator being utilized for the heat recovery cycle. The ability of superchilling to operate at maximum efficiency can be coupled with high power capability by selectively increasing the energy input to the recuperative cycle thereby increasing the degree of superchilling. Thus, referring to FIG. 9, still another embodiment of the present invention is illustrated wherein a regenerator bypass circuit 49 is provided to duct the turbine exhaust gases around the regenerator 36 and directly into the waste-heat boiler 37 of the heat recovery cycle thereby increasing the energy available for superchilling the inlet air. An adjustable bypassvalve 50 in the circuit 49 permits the power output and/or thermal efficiency of the gas turbine power plant to be modulated in a controlled manner.

Power output of the gas turbine power plant below the point of maximum efficiency can also be effectively modulated. Preferably, this modulation would be accomplished by reducing the degree of supercharging, for example, throttling the first steam turbine 38 coupled to drive the fan 16, while maintaining the same degree of chilling. Still lower power outputs could be obtained by controlled exhausting to the atmosphere of the turbine exhaust gases from the regenerator 36 to reduce the energy input to the heat recovery cycle thus reducing the degree of chilling. With complete exhausting of the turbine exhaust gases, the gas turbine power plant operates in the conventional manner without any supercharging or chilling of the compressor inlet air.

Accordingly, referring again to FIG. 9, a second adjustable bypass valve 51 is provided to permit selective venting to the atmosphere of the turbine exhaust gases from the regenerative heat exchanger 36 and/or the bypass circuit 49. Adjustment of the second bypass valve 51 provides selective reduction of the energy available to the heat recovery cycle which in turn reduces the degree of superchilling of the compressor inlet air.

By way of further example, the operating characteristics for the embodiment of the gas turbine power plant of FIG. 9 are listed therein. The superchilled gas turbine power plant would produce about 39.6 megawatts of power at a heat rate of about 8480 Btu/Kwh LI-IV.

Other means are available to supercharge the ambient-inlet air. For example, fan 16 can be replaced by a moderately low pressure rise compressor or blower. Similarly, other means are also available to chill the inlet air. For example, the compression refrigeration unit 19 can be replaced by an absorption refrigeration unit. Generally speaking, in an absorption refrigeration unit, the compressor 21 and motor 22 in the compression refrigeration unit would be replaced by an absorber, a generator, a pump, a heat exchanger and a reducing valve. Waste-heat in the turbine exhaust gases would provide the heat input to the absorption refrigeration unit.

Although the gas turbine power plant of the present invention has been describedas a power source for an electrical generator, it is to be understood that the improved gas turbine power plant has other applications. For example, the gas turbine power plant has application as a natural gas pipeline compressor drive.

The embodiments of the gas turbine power plant described above are for the purpose, of illustrating the broader aspects of the present invention, and the advantages attendant therein. Other modifications and variations of the embodiments will-be apparent to those skilled in mean, and they may be made without de- 1. An improved gas turbine having increased performance, the gas turbine including a compressor for receiving inlet gas and compressing the same, means for heating the compressed gas, and a turbine for expanding the heated compressed gas, the improvement comprising;

a. means for supercharging the inlet gas before it is received by the compressor; and

b. means for chilling the supercharged inlet gas before it is received by the compressor, the chilling means including a refrigerant for the direct transfer of heat from the supercharged gas thereto; and e 0. means for regeneratively heating the compressed gas from the compressor with waste-heat from the exhaust gases of the turbine before the compressed gas passes to the compressed gas heating means; and v (1. means for recovering a portion of.the waste-heat energy from the exhaust gases of the turbine and for converting the waste-heat energy into energy for driving the supercharging means and for driving the chilling means; and v e. means for selectively controlling the portion of the waste-heat energy converted to energy for driving the supercharging means and for driving the chilling means for providing selective control over the amount of energy available to superchill the inlet gas thereby providing for selective control of the performance of the gas turbine.

2. An improved gas turbine having increased performance, the gas turbine including a compressor for receiving inlet gas and compressing the same, means for heating the compressed gas, and a turbine for expanding the heated compressed gas, the improvement comprising:

a. means for supercharging the inlet gas before it is received by the compressor; and

b. means for chilling the supercharged inlet gas before it is received by the compressor, the chilling means including a refrigerant for the direct transfer of heat from the supercharged gas thereto; and

c. means for recovering a portion of the wasteheat energy from the exhaust gases of the turbine and for converting the waste-heat energy into energy for driving the supercharging means and for driving the chilling means; and

d. means for selectively controlling the portion of the waste-heat energy converted to energy for driving the supercharging means and for driving the chill ing means for providing selective control over the amount of energy available to superchill the inlet gas thereby providing for selective control of the performance of the gas turbine.

3. An improved gas turbine having increased performance, the gas'turbine including a compressor for receiving inlet gas and compressing the same, means for heating the compressed gas, and a turbine for expanding the heated compressed gas, the improvement comprising: v v

a. means for supercharging the inlet gas before it is received by the compressor; and

b. means for chilling the supercharged inlet gas before it is received by the compressor; and

c. means for recovering a portion of the wasteheat energy from the exhaust gases of the turbine and for converting the waste-heat energy into energy for driving the supercharging means and for driving the chilling means;

d. means for selectively controlling the portion of the waste-heat energy converted to energy for-driving the supercharging means and for driving the chilling means for providing selective control over the amount of energy available to superchill the inlet gas thereby providing for selective control of the performance of the gas turbine.

, 4. An improved gas turbine according to claim 3, further comprising means 'for regneratively heating the compressed gas from the compressor with waste-heat from the exhaust gases of the turbine before the compressed gas passes to the compressed gas heating means.

5. A method for increasing the performance of a gas turbine, the gas -turbine including a compressor for receiving inlet gas and compressing-the same, means for heating the compressed gas, and a turbine for expanding the heated compressed gas to extract work therefrom, the method comprising the steps of:

a. supercharging the inlet gas by a fan or a blower device before it is received by the compressor by increasing the pressure of the inlet gas in accordance with a supercharging pressure ratio in a range of pressure ratios extending from about 1.1 to about 1.75; i

b. chilling the supercharged inlet gas before it is received by the-compressor by the direct transfer of heat from the supercharged gas to the refrigerant of a refrigeration system;

c. regeneratively heating the compressed gas from the compressor with waste-heat from the exhaust gases of the turbine;

d. recovering a portion of the waste-heat energy from the exhaust gases of the turbine and converting the waste-heat energy into energy for superchilling the compressor inlet air; and I e. selectively controlling the portion of the wasteheat energy converted to energy for superchilling the compressor inlet air thereby selectively controlling the performance of the gas turbine.

before it is received by the compressor by increasing the pressure of the inlet gas in accordance with a supercharging pressure ratio in a range of pressure ratios extending from about 1.1 to about 1.75;

b. means for chilling the supercharged inlet gas before it is received by the compressor, the chilling means including a refrigerant for the direct transfer of heat from the supercharged gas thereto;

c. means for regeneratively heating the compressed gas from the compressor with waste-heat from the exhaust gases of the turbine before the compressed gas passes to the compressed gas heating means;

d. means for recovering a portion of the waste-heat energy from the exhaust gases of the turbine and for converting the waste-heat energy into energy for driving the supercharging means and for driving the chilling means; and

. means for selectively controlling the portion of the waste-heat energy converted to energy for driving the supercharging means and for driving the chilling means for providing selective control over the amount of energy available to superchill the inlet gas thereby providing for selective control of the performance of the gas turbine.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2322717 *Dec 15, 1939Jun 22, 1943Friedrich NettelApparatus for combustion turbines
US2633707 *Nov 13, 1947Apr 7, 1953Anxionnaz ReneCompound plant for producing mechanical power and heating steam with gas and steam turbines
US2663144 *May 6, 1948Dec 22, 1953Laval Steam Turbine CoCombined gas and steam power plant
US3153442 *Jun 26, 1961Oct 20, 1964David H SilvernHeating and air conditioning apparatus
US3479541 *Sep 11, 1962Nov 18, 1969Allis Louis CoHigh speed liquid cooled motors
US3500636 *Feb 14, 1967Mar 17, 1970Ass Elect IndGas turbine plants
US3631673 *Aug 5, 1970Jan 4, 1972Electricite De FrancePower generating plant
CA505044A *Aug 10, 1954Sulzer AgThermal power generating processes and systems
GB679007A * Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3882671 *Jan 2, 1974May 13, 1975Brayton Cycle Improvement AssGasification method with fuel gas cooling
US3971211 *Apr 2, 1974Jul 27, 1976Mcdonnell Douglas CorporationThermodynamic cycles with supercritical CO2 cycle topping
US3974642 *Jan 18, 1974Aug 17, 1976Fives-Cail Babcock Societe AnonymeHybrid cycle power plant with heat accumulator for storing heat exchange fluid transferring heat between cycles
US3978663 *Jan 9, 1975Sep 7, 1976Sulzer Brothers LimitedProcess and apparatus for evaporating and heating liquified natural gas
US4178754 *Jul 13, 1977Dec 18, 1979The Hydragon CorporationThrottleable turbine engine
US4204401 *Jul 21, 1977May 27, 1980The Hydragon CorporationTurbine engine with exhaust gas recirculation
US4244191 *Dec 20, 1978Jan 13, 1981Thomassen Holland B.V.Gas turbine plant
US4907405 *Jan 24, 1989Mar 13, 1990Union Carbide CorporationProcess to cool gas
US5193337 *Jan 15, 1992Mar 16, 1993Abb Stal AbMethod for operating gas turbine unit for combined production of electricity and heat
US5203161 *Oct 30, 1990Apr 20, 1993Lehto John MMethod and arrangement for cooling air to gas turbine inlet
US5212942 *Dec 9, 1991May 25, 1993Tiernay Turbines, Inc.Cogeneration system with recuperated gas turbine engine
US5241817 *Oct 30, 1991Sep 7, 1993George Jr Leslie CScrew engine with regenerative braking
US5321944 *Jun 28, 1993Jun 21, 1994Ormat, Inc.Power augmentation of a gas turbine by inlet air chilling
US5323603 *Mar 9, 1993Jun 28, 1994Tiernay TurbinesIntegrated air cycle-gas turbine engine
US5388395 *Apr 27, 1993Feb 14, 1995Air Products And Chemicals, Inc.Use of nitrogen from an air separation unit as gas turbine air compressor feed refrigerant to improve power output
US5444971 *Apr 28, 1993Aug 29, 1995Holenberger; Charles R.Method and apparatus for cooling the inlet air of gas turbine and internal combustion engine prime movers
US5463873 *Dec 6, 1993Nov 7, 1995Cool Fog Systems, Inc.Method and apparatus for evaporative cooling of air leading to a gas turbine engine
US5537813 *Mar 7, 1995Jul 23, 1996Carolina Power & Light CompanyGas turbine inlet air combined pressure boost and cooling method and apparatus
US5622044 *Jan 16, 1996Apr 22, 1997Ormat Industries Ltd.Apparatus for augmenting power produced from gas turbines
US5632148 *May 12, 1993May 27, 1997Ormat Industries Ltd.Power augmentation of a gas turbine by inlet air chilling
US5655373 *Sep 28, 1995Aug 12, 1997Kabushiki Kaisha ToshibaGas turbine intake air cooling apparatus
US5666800 *Jun 14, 1994Sep 16, 1997Air Products And Chemicals, Inc.Gasification combined cycle power generation process with heat-integrated chemical production
US5782093 *Mar 6, 1997Jul 21, 1998Kabushiki Kaisha ToshibaGas turbine intake air cooling apparatus
US5806298 *Sep 20, 1996Sep 15, 1998Air Products And Chemicals, Inc.Gas turbine operation with liquid fuel vaporization
US5839270 *Dec 20, 1996Nov 24, 1998Jirnov; OlgaSliding-blade rotary air-heat engine with isothermal compression of air
US5865023 *Aug 12, 1997Feb 2, 1999Air Products And Chemicals, Inc.Gasification combined cycle power generation process with heat-integrated chemical production
US6050083 *Apr 22, 1996Apr 18, 2000Meckler; MiltonGas turbine and steam turbine powered chiller system
US6119445 *Dec 12, 1996Sep 19, 2000Ormat Industries Ltd.Method of and apparatus for augmenting power produced from gas turbines
US6209307May 5, 1999Apr 3, 2001Fpl Energy, Inc.Thermodynamic process for generating work using absorption and regeneration
US6308512Sep 2, 1999Oct 30, 2001Enhanced Turbine Output Holding, LlcSupercharging system for gas turbines
US6332321 *Sep 18, 2000Dec 25, 2001Ormat Industries Ltd.Apparatus for augmenting power produced from gas turbines
US6422019 *Dec 21, 2001Jul 23, 2002Ormat Industries Ltd.Apparatus for augmenting power produced from gas turbines
US6430931 *Oct 22, 1997Aug 13, 2002General Electric CompanyGas turbine in-line intercooler
US6442942Dec 30, 1999Sep 3, 2002Enhanced Turbine Output Holding, LlcSupercharging system for gas turbines
US6499303 *Apr 18, 2001Dec 31, 2002General Electric CompanyMethod and system for gas turbine power augmentation
US6530224 *Mar 28, 2001Mar 11, 2003General Electric CompanyGas turbine compressor inlet pressurization system and method for power augmentation
US6536229 *Aug 29, 2000Mar 25, 2003Kawasaki Thermal Engineering Co., Ltd.Absorption refrigerator
US6539720 *Nov 6, 2001Apr 1, 2003Capstone Turbine CorporationGenerated system bottoming cycle
US6615585Jan 25, 2002Sep 9, 2003Mitsubishi Heavy Industries, Ltd.Intake-air cooling type gas turbine power equipment and combined power plant using same
US6651443 *Oct 10, 2001Nov 25, 2003Milton MecklerIntegrated absorption cogeneration
US6688136 *Nov 27, 2002Feb 10, 2004General Electric CompanyGenerator system including an electric generator and a centrifugal chiller
US6694772 *Aug 5, 2002Feb 24, 2004Ebara CorporationAbsorption chiller-heater and generator for use in such absorption chiller-heater
US6798079 *Jul 11, 2002Sep 28, 2004Siemens Westinghouse Power CorporationTurbine power generator including supplemental parallel cooling and related methods
US6877323 *Nov 27, 2002Apr 12, 2005Elliott Energy Systems, Inc.Microturbine exhaust heat augmentation system
US6880343 *Dec 4, 2002Apr 19, 2005William L. KopkoSupercharged gas turbine with improved control
US6880344 *Jun 17, 2003Apr 19, 2005Utc Power, LlcCombined rankine and vapor compression cycles
US6892522 *Nov 13, 2002May 17, 2005Carrier CorporationCombined rankine and vapor compression cycles
US6962056Jul 22, 2004Nov 8, 2005Carrier CorporationCombined rankine and vapor compression cycles
US7065953 *Jun 9, 2000Jun 27, 2006Enhanced Turbine Output HoldingSupercharging system for gas turbines
US7168233 *Dec 12, 2005Jan 30, 2007General Electric CompanySystem for controlling steam temperature
US7299619Dec 8, 2004Nov 27, 2007Siemens Power Generation, Inc.Vaporization of liquefied natural gas for increased efficiency in power cycles
US7405491 *Jul 10, 2006Jul 29, 2008Kobe Steel, Ltd.Electric power generating device
US7406829 *May 18, 2005Aug 5, 2008General Electric CompanyCryogenic liquid oxidizer cooled high energy system
US7762054Jul 30, 2008Jul 27, 2010Donald Charles EricksonThermally powered turbine inlet air chiller heater
US7810332 *Oct 12, 2006Oct 12, 2010Alstom Technology LtdGas turbine with heat exchanger for cooling compressed air and preheating a fuel
US7980081Dec 6, 2005Jul 19, 2011Fluor Technologies CorporationConfigurations and methods for LNG fueled power plants
US7980092Feb 4, 2010Jul 19, 2011Husky Injection Molding Systems Ltd.Compressor
US8037703 *Jul 31, 2008Oct 18, 2011General Electric CompanyHeat recovery system for a turbomachine and method of operating a heat recovery steam system for a turbomachine
US8051654 *Jan 31, 2008Nov 8, 2011General Electric CompanyReheat gas and exhaust gas regenerator system for a combined cycle power plant
US8074458Jul 31, 2008Dec 13, 2011General Electric CompanyPower plant heat recovery system having heat removal and refrigerator systems
US8356466Dec 11, 2008Jan 22, 2013General Electric CompanyLow grade heat recovery system for turbine air inlet
US8397504 *Feb 8, 2010Mar 19, 2013Global Alternative Fuels, LlcMethod and apparatus to recover and convert waste heat to mechanical energy
US8468830 *Dec 11, 2008Jun 25, 2013General Electric CompanyInlet air heating and cooling system
US8584464 *Dec 20, 2005Nov 19, 2013General Electric CompanyGas turbine engine assembly and method of assembling same
US8616005Sep 9, 2009Dec 31, 2013Dennis James Cousino, Sr.Method and apparatus for boosting gas turbine engine performance
US20100095681 *Oct 6, 2009Apr 22, 2010Enis Ben MMethod and apparatus for using compressed air to increase the efficiency of a fuel driven turbine generator
US20100242429 *Mar 25, 2009Sep 30, 2010General Electric CompanySplit flow regenerative power cycle
US20100257837 *Apr 14, 2009Oct 14, 2010General Electric CompanySystems involving hybrid power plants
US20110193346 *Feb 8, 2010Aug 11, 2011Carlos GuzmanMethod and apparatus to recover and convert waste heat to mechanical energy
US20110277476 *May 14, 2010Nov 17, 2011Michael Andrew MinovitchLow Temperature High Efficiency Condensing Heat Engine for Propelling Road Vehicles
CN1841885BMar 29, 2005Oct 27, 2010中国科学院电工研究所Self-circulation cooling loop of heavy current fixture wire
CN101027468BNov 12, 2003May 29, 2013开利公司Combined rankine and vapor compression cycles
CN101749116BDec 11, 2009Jan 29, 2014通用电气公司用于涡轮机空气进口的低品位热回收系统
EP0846220A2 *Aug 22, 1996Jun 10, 1998Charles R. KohlenbergerMethod and apparatus for cooling the inlet air of gas turbine and internal combustion engine prime movers
EP0945607A2 *Mar 24, 1999Sep 29, 1999Mitsubishi Heavy Industries, Ltd.Intake-air cooling for a gas turbine of a combined power plant
EP0990801A1 *Sep 30, 1998Apr 5, 2000Asea Brown Boveri AGIsothermal compression with a hydraulic compressor
EP1528239A1 *Oct 29, 2004May 4, 2005General Electric CompanyMethods and apparatus for operating gas turbine engines with intercoolers between compressors
EP2149765A2 *Jul 23, 2009Feb 3, 2010General Electric CompanyHeat Recovery System
EP2196651A2 *Dec 1, 2009Jun 16, 2010General Electric CompanyLow grade heat recovery system for turbine air inlet
WO1996035050A1May 2, 1995Nov 7, 1996Todd W BeadleMethod and apparatus for increasing the operational capacity and efficiency of a combustion turbine
WO2001000975A1 *Jun 9, 2000Jan 4, 2001Work Smart Energy Entpr IncSupercharging system for gas turbines
WO2003100233A1 *May 15, 2003Dec 4, 2003Enhanced Turbine Output HoldinHighly supercharged gas turbine and power generating system
WO2004044386A2 *Nov 12, 2003May 27, 2004Carrier CorpCombined rankine and vapor compression cycles
WO2006012406A2 *Jul 20, 2005Feb 2, 2006Carrier CorpCombined rankine and vapor compression cycles
WO2006068832A1 *Dec 6, 2005Jun 29, 2006Fluor Tech CorpConfigurations and methods for lng fueled power plants
Classifications
U.S. Classification60/772, 60/39.83, 60/39.182, 60/728
International ClassificationF02C7/12, F01K23/06, F01K27/00, F01K27/02, F02C7/08, F02C7/143, F02C7/10, F01K23/10
Cooperative ClassificationF01K23/10, F02C7/143, F01K27/02, F02C7/10
European ClassificationF01K27/02, F01K23/10, F02C7/143, F02C7/10