Method of chilling inlet air for gas turbines

Abstract

A method for cooling inlet air to a gas turbine is provided. For example, a method is described including passing inlet air through a cooling coil that includes an opening for receiving the inlet air and that is operably connected to a gas turbine power plant. The gas turbine power plant may include at least one gas turbine, and at least one gas turbine inlet which receives the inlet air. The method may further include passing circulating water through a water chiller at a first flow rate to reduce the temperature of the circulating water, the water chiller including a conduit through which the circulating water is capable of passing and passing the circulating water having the first flow rate through the cooling coil in an amount sufficient to lower the temperature of the inlet air. Additionally, the method may include reducing the flow rate of the circulating water passing through the water chiller, passing the circulating water through a water chiller at a second flow rate to reduce the temperature of the circulating water, the second flow rate being lower than the first flow rate, and passing the circulating water having the second flow rate through the cooling coil in an amount sufficient to lower the temperature of the inlet air.A system for cooling inlet air to a gas turbine is provided. In order to maintain a desired level of efficiency for a gas turbine plant, water is passed through a chiller to lower the water temperature. The cooled water is then circulated through coils disposed in the inlet air of the gas turbine, thereby cooling the inlet air to the gas turbine. The system may include a thermal energy storage tank for storing chilled water prior to circulation through the coils. The system may also utilize an air temperature set point selected to achieve a desired output or to meet load requirement for the gas turbine plant. The temperature or flow rate of the cooled water may be adjusted to achieve the selected air temperature set point.

1. A method of chilling inlet air to a combined cycle gas turbine plant, comprising:
 a. a gas turbine plant that includes a gas turbine and a gas turbine air inlet and a steam turbine; 
 b. providing a system of circulating liquid chilling water including a chilling system that includes a first chiller; 
 c. providing a storage tank which is operably connected to the chilling system, the storage tank containing a column of water characterized by a top and a bottom; 
 c.d. removing water from the storage tank, passing at least a portion of the liquid chilling water through the first chiller, the liquid chilling water passing through the first chiller being lowered to a first temperature and then introducing at least a portion of the removed water into the water column, wherein the average temperature of the water in the storage tank is lowered; 
 d.e. providing an inlet air chiller, comprising a cooling coil through which liquid chilling water passes, for lowering the temperature of inlet air being fed to the gas turbine compressor through heat transfer between the liquid chilling water passing through the cooling coil and the inlet air, wherein the inlet air chiller provides a liquid chilling water temperature rise; 
 e.f. chilling the inlet air by removing water from the water column and then directing the liquid chilling water through the cooling coil of the inlet air chiller to make heat transfer contact between the liquid chilling water and the inlet air; and 
 f.g. controlling the leaving air temperature off the cooling coil to maintain a leaving air temperature slightly above the dew point temperature of the ambient air to maintain high efficiency on the power gas turbine plant. 
 
     
     
       2. The method of  claim 1 , wherein an amount of circulating chilled water flow rate is varied to the cooling coil to maintain a leaving air temperature slightly above the dew point temperature of the ambient air. 
     
     
       3. The method of  claim 1 , wherein the temperature of the circulating chilled water is varied to the cooling coil to maintain a leaving air temperature slightly above the dew point temperature of the ambient air. 
     
     
       4. The method of  claim 1 , wherein a circulating chilled water flow rate or the circulating chilled water temperature is varied to the cooling coil to maintain a relative humidity off the coil to below about 95% to about 99% RH. 
     
     
       5. A method of chilling inlet air to a gas turbine, comprising:
 a. a gas turbine that includes a gas turbine inlet; 
 b. providing a system of circulating liquid chilling water solution wherein the water solution contains water plus an additive which is capable of reducing the freezing point of water; 
 c. passing at least a portion of the liquid chilling water solution through a first chiller and then a second chiller, the liquid chilling water solution passing through the first chiller being lowered to a first temperature; and the liquid chilling water solution passing through the second chiller being lowered to a second temperature which is lower than the first; 
 d. providing an inlet air chiller, comprising a cooling coil through which the liquid chilling water solution passes, for lowering the temperature of inlet air being fed to the gas turbine compressor through heat transfer between the liquid chilling water solution passing through the cooling coil and the inlet air, and 
 e. chilling the inlet air by directing the liquid chilling water solution through the cooling coil of the inlet air chiller to make heat transfer contact between the liquid chilling water and the inlet air. 
 
     
     
       6. The method of  claim 5 , wherein the chilling water solution comprises an additive of sodium nitrate in an amount sufficient to decrease the freezing temperature of the chilling water solution. 
     
     
       7. The method of  claim 5 , wherein the chilling water solution comprises an additive of potassium formate in an amount sufficient to decrease the freezing temperature of the chilling water solution. 
     
     
       8. The method of claim 1, wherein the controlling the leaving air temperature off the cooling coil is accomplished by maintaining a leaving air temperature slightly above the dew point temperature of the ambient air.  
     
     
       9. The method of claim 1, wherein the controlling the leaving air temperature off the cooling coil is based on an identified operating parameter associated with the gas turbine plant.  
     
     
       10. The method of claim 9, wherein the operating parameter is the dew point temperature of the ambient air.  
     
     
       11. The method of claim 10, wherein the leaving air temperature is maintained slightly above the operating parameter.  
     
     
       12. The method of claim 9, wherein the operating parameter is the humidity of the ambient air.  
     
     
       13. The method of claim 9, wherein the operating parameter is the capacity requirement for the gas turbine plant.  
     
     
       14. The method of claim 1, wherein the inlet air temperature is adjusted by changing the flow rate of the liquid chilling water passing through the cooling coil. 
     
     
       15. The method of claim 14, wherein the inlet air temperature is adjusted when the temperature difference between the liquid chilling water entering the cooling coil and the liquid chilling water leaving the cooling coil reaches a desired level.  
     
     
       16. The method of claim 14, further comprising:
 providing a pump for circulating the liquid chilling water,   wherein the flow rate of the liquid chilling water is reduced by lowering the speed (RPM) of the pump via a variable frequency drive on the pump.    
     
     
       17. The method of claim 1, wherein the inlet air temperature is adjusted by lowering the temperature of the liquid chilling water when the inlet air temperature increases above a setpoint.  
     
     
       18. The method of claim 1, wherein the inlet air temperature is adjusted by providing a wet bulb temperature sensor to monitor the ambient air wet bulb temperature entering the cooling coil and lowering the temperature of the liquid chilling water when the ambient air wet bulb temperature increases.  
     
     
       19. A method for chilling inlet air to a gas turbine, comprising:
 providing a system of circulating water including a chilling system having a first chiller, wherein water can pass through the first chiller, the water passing through the first chiller being lowered to a first temperature;   providing an inlet air chiller for lowering the temperature of air being fed to a gas turbine compressor through heat transfer between the circulating water and the air;   providing a storage tank which is operably connected to the system of circulating water, the storage tank containing a column of water characterized by a top and a bottom;   during a charge cycle, removing water from the storage tank, passing at least a portion of the removed water through the chilling system to lower the temperature of water passing through the chilling system and then introducing at least a portion of the removed water into the storage tank at a point proximate the bottom of the water column, wherein the average temperature of the water in the storage tank is lowered;   during a discharge cycle, chilling the air by removing water from the storage tank from a point proximate the bottom of the water column and then passing at least a portion of the removed water through the inlet air chiller to make heat transfer contact between that portion of the removed water and the air, such that the temperature of the air is lowered; and   adjusting the temperature of the air based on an air temperature setpoint that is varied by a control setpoint signal from a controls system which adjusts the air temperature setpoint to maintain the desired gas turbine output.   
     
     
       20. A method for chilling inlet air to a gas turbine, comprising:
 providing a system of circulating water including a chilling system having a first chiller, wherein water can pass through the first chiller, the water passing through the first chiller being lowered to a first temperature;   providing an inlet air chiller for lowering the temperature of air being fed to a gas turbine compressor through heat transfer between the circulating water and the air;   providing a storage tank which is operably connected to the system of circulating water, the storage tank containing a column of water characterized by a top and a bottom;   during a charge cycle, removing water from the storage tank, passing at least a portion of the removed water through the chilling system to lower the temperature of water passing through the chilling system and then introducing at least a portion of the removed water into the storage tank at a point proximate the bottom of the water column, wherein the average temperature of the water in the storage tank is lowered;   during a discharge cycle, chilling the air by removing water from the storage tank from a point proximate the bottom of the water column and then passing at least a portion of the removed water through the inlet air chiller to make heat transfer contact between that portion of the removed water and the air, such that the temperature of the air is lowered;   selecting a desired air temperature setpoint based on load requirements of the gas turbine; and   adjusting the temperature of the air to the desired air temperature setpoint.   
     
     
       21. The method of claim 20, wherein the temperature of the air is adjusted by changing the flow rate of the circulating water passing through the first chiller. 
     
     
       22. The method of claim 20, wherein the temperature of the air is adjusted in response to predetermined changes in ambient air wet bulb temperature. 
     
     
       23. The method of claim 20, wherein the temperature of the air is adjusted in response to predetermined changes in ambient air enthalpy. 
     
     
       24. The method of claim 20, wherein the temperature of the air is adjusted by varying the circulating water flow rate. 
     
     
       25. The method of claim 20, wherein the temperature of the air is adjusted by varying the circulating water temperature. 
     
     
       26. The method of claim 20, wherein the temperature of the air is adjusted by heating the circulating water. 
     
     
       27. The method of claim 26, wherein the circulating water is passed from the inlet air chiller to a heater and back to the inlet air chiller to increase the temperature of the air. 
     
     
       28. The method of claim 26, wherein the circulating water is heated to keep the mass flow of the air within a desirable mass flow range. 
     
     
       29. The method of claim 20, wherein the air temperature setpoint is a function of both ambient wet bulb temperature of the air and the temperature difference between the circulating water entering the inlet air chiller and the circulating water leaving the inlet air chiller. 
     
     
       30. The method of claim 20, further comprising:
 providing chilling system controls and turbine controls,   wherein the chilling system controls communicate with the turbine controls to control setpoints to optimize gas turbine output.   
     
     
       31. The method of claim 20 wherein the first chiller is turned off during peak periods to minimize the total amount of electricity required to power the chilling system. 
     
     
       32. The method of claim 20, wherein the air temperature is adjusted by changing the flow rate of the circulating water passing through the inlet air chiller. 
     
     
       33. The method of claim 20, wherein the air temperature is adjusted when the temperature difference between the circulating water entering the inlet air chiller and the circulating water leaving the inlet air chiller reaches a desired level. 
     
     
       34. A method for chilling inlet air to a gas turbine, comprising:
 providing a system of circulating water including a chilling system having a first chiller, wherein water can pass through the first chiller, the water passing through the first chiller being lowered to a first temperature;   providing an inlet air chiller for lowering the temperature of air being fed to a gas turbine compressor through heat transfer between the circulating water and the air;   providing a storage tank which is operably connected to the system of circulating water, the storage tank containing a column of water characterized by a top and a bottom;   during a charge cycle, removing water from the storage tank, passing at least a portion of the removed water through the chilling system to lower the temperature of water passing through the chilling system and then introducing at least a portion of the removed water into the storage tank at a point proximate the bottom of the water column, wherein the average temperature of the water in the storage tank is lowered;   during a discharge cycle, chilling the air by removing water from the storage tank from a point proximate the bottom of the water column and then passing at least a portion of the removed water through the inlet air chiller to make heat transfer contact between that portion of the removed water and the air, such that the temperature of the air is lowered; and   maintaining the temperature of the air at a desired air temperature setpoint based on load requirements of the gas turbine.   
     
     
       35. The method of claim 34, wherein the air temperature is maintained by reducing the flow rate of the circulating water passing through the inlet air chiller. 
     
     
       36. The method of claim 34, wherein the air temperature is maintained by reducing the flow rate of the circulating water passing through the first chiller. 
     
     
       37. The method of claim 34, wherein the air temperature is maintained by adjusting the temperature of the circulating water entering the inlet air chiller. 
     
     
       38. The method of claim 34, wherein the air temperature is maintained by heating the circulating water. 
     
     
       39. The method of claim 34, wherein the air temperature setpoint is a function of both ambient wet bulb temperature of the air and the temperature difference between the circulating water entering the inlet air chiller and the circulating water leaving the inlet air chiller. 
     
     
       40. The method of claim 34, wherein the air temperature is maintained by utilizing a temperature sensor contacting the air to monitor the temperature of the air. 
     
     
       41. The method of claim 34, wherein the air temperature is maintained by providing a wet bulb temperature sensor to monitor the ambient air wet bulb temperature entering the inlet air chiller. 
     
     
       42. A method for chilling inlet air to a gas turbine, comprising:
 providing a system of circulating water including a chilling system having a first chiller, wherein water can pass through the first chiller, the water passing through the first chiller being lowered to a first temperature;   providing an inlet air chiller for lowering the temperature of air being fed to a gas turbine compressor through heat transfer between the circulating water and the air;   providing a storage tank which is operably connected to the system of circulating water, the storage tank containing a column of water characterized by a top and a bottom;   during a charge cycle, removing water from the storage tank, passing at least a portion of the removed water through the chilling system to lower the temperature of water passing through the chilling system and then introducing at least a portion of the removed water into the storage tank at a point proximate the bottom of the water column, wherein the average temperature of the water in the storage tank is lowered;   during a discharge cycle, chilling the air by removing water from the storage tank from a point proximate the bottom of the water column and then passing at least a portion of the removed water through the inlet air chiller to make heat transfer contact between that portion of the removed water and the air, such that the temperature of the air is lowered;   selecting a desired air temperature setpoint for the air; and   altering the air temperature setpoint of the gas turbine.   
     
     
       43. The method of claim 42, wherein the air temperature setpoint is altered based on changes in the load requirements of the gas turbine. 
     
     
       44. The method of claim 42, wherein the air temperature setpoint is altered based on the time of day. 
     
     
       45. The method of claim 42, wherein the air temperature setpoint is altered based on the ambient temperature. 
     
     
       46. The method of claim 42, wherein the air temperature setpoint is altered at off-design ambient temperatures. 
     
     
       47. The method of claim 46, wherein the air temperature setpoint is increased at reduced off-design ambient temperatures. 
     
     
       48. A method for chilling inlet air to a gas turbine, comprising:
 providing a system of circulating water including a chilling system having a first chiller and a second chiller, the first and second chillers being arranged in series, wherein water can pass through the first and second chillers, the water passing through the first chiller being lowered to a first temperature, the water passing through the second chiller being lowered to a second temperature that is lower than the first temperature, thus providing a staged temperature drop;   providing an inlet air chiller for lowering the temperature of the air being fed to a gas turbine compressor through heat transfer between the circulating water and the air;   providing a storage tank which is operably connected to the system of circulating water, the storage tank containing water and having a bottom;   during a charge cycle, removing water from the storage tank, passing at least a portion of the removed water through the chilling system to lower the temperature of water passing through the chilling system and then introducing at least a portion of the removed water into the storage tank at a point proximate the bottom of the tank, wherein the average temperature of the water in the storage tank is lowered; and   during a discharge cycle, chilling the air by removing water from the storage tank from a point proximate the bottom of the tank and then passing at least a portion of the removed water to the inlet air chiller to make heat transfer contact between that portion of the removed water and the air, such that the temperature of the air is lowered.   
     
     
       49. The method of claim 48, further comprising adjusting the air temperature by changing the flow rate of the circulating water passing through the inlet air chiller. 
     
     
       50. The method of claim 48, further comprising controlling leaving air temperature from the inlet air chiller based on an identified operating parameter associated with the gas turbine. 
     
     
       51. The method of claim 50, wherein the operating parameter is the capacity requirement for the gas turbine. 
     
     
       52. A method for chilling inlet air to a gas turbine, comprising:
 providing a system of circulating water including a chilling system having a first duplex chiller and a second duplex chiller, the first and second duplex chillers being arranged in series;   providing an inlet air chiller for lowering the temperature of air being fed to a gas turbine compressor through heat transfer between the circulating water and the air;   passing water through the first and second duplex chillers, wherein the water passing through the first duplex chiller is lowered to a first temperature and then a second temperature that is lower than the first temperature,   passing water through the second duplex chiller, wherein the water temperature passing through the second duplex chiller is lowered to a third temperature that is lower than the second temperature and then a fourth temperature that is lower than the third temperature, thus providing a four stage temperature drop of the water; and   passing at least a portion of the chilled water through the inlet air chiller resulting in heat transfer between the chilled water and the air, such that the temperature of the air is lowered.   
     
     
       53. The method of claim 52, further comprising storing a portion of the chilled water from one of the chillers in a storage tank which is operably connected to the inlet air chiller. 
     
     
       54. The method of claim 52 wherein at least some of the circulating chilling water is circulated through a thermal water storage tank during a charging cycle. 
     
     
       55. A method for chilling inlet air to a gas turbine, comprising:
 providing a system of circulating water including a chilling system having a first chiller and a second chiller and a third chiller, the first and second and third chillers being arranged in series;   providing an inlet air chiller for lowering the temperature of air being fed to a gas turbine compressor through heat transfer between the circulating water and the air;   passing water through the first, second and third chillers, wherein water passing through the first chiller is lowered to a first temperature, water passing through the second chiller is lowered to a second temperature that is lower than the first temperature, and water passing through the third chiller is lowered to a third temperature that is lower than the second temperature, thus providing a staged temperature drop of the water; and   passing at least a portion of the chilled water through the inlet air chiller resulting in heat transfer between the chilled water and the air, such that the temperature of the air is lowered.   
     
     
       56. A method for chilling inlet air to a gas turbine, comprising:
 providing a system of circulating water including a chilled water circuit having a first duplex chiller and a second duplex chiller, the first and second duplex chillers being arranged in series for circulating chilled water in a first flow direction through the chilled water circuit;   providing a circulating condenser water circuit that circulates cooling water through the second duplex chiller and then through the first duplex chiller such that the condenser water circuit is counterflow to the chilled water circuit;   providing an inlet air chiller for lowering the temperature of air being fed to a gas turbine compressor through heat transfer between the circulating water and the air;   passing chilled water through the first duplex chiller, wherein the chilled water passing through the first duplex chiller is lowered from a first temperature to a second temperature that is lower than the first temperature;   passing the chilled water from the first duplex chiller through the second duplex chiller, wherein the chilled water temperature is lowered to a third temperature that is lower than the second temperature, thus providing a staged temperature drop of the chilled water;   passing at least a portion of the chilled water from the chilled water circuit through the inlet air chiller resulting in heat transfer between the chilled water and the air, such that the temperature of the air is lowered.   
     
     
       57. A method for chilling inlet air to a gas turbine, comprising:
 providing a system of circulating water including a chilling system having a first chiller and a second chiller, the first and second chillers being arranged in series;   passing water through the first chiller to lower the water temperature to a first temperature;   thereafter, passing the water through the second chiller to lower the water temperature to a second temperature that is lower than the first temperature, thus providing a staged temperature drop;   providing an inlet air chiller for lowering the temperature of the air being fed to a gas turbine compressor through heat transfer between the circulating water and the inlet air;   providing a thermal water storage tank which is operably connected to the system of circulating water, the thermal water storage tank containing chilling water;   during a charge cycle, removing water from the storage tank, passing at least a portion of the removed water through the chilling system to lower the temperature of water passing through the chilling system and then introducing at least a portion of the removed water into the storage tank; and   during a discharge cycle, chilling the air by removing chilling water from the thermal water storage tank and then passing at least a portion of the removed water to the inlet air chiller resulting in heat transfer between the chilled water and the air, such that the temperature of the air is lowered; and   varying the flow of chilling water through the inlet air chiller.   
     
     
       58. The method of claim 57, wherein the staged temperature drop is maintained at least 20° F. or above. 
     
     
       59. The method of claim 57, wherein the inlet air chiller is a specially circuited cooling coil designed to provide a staged temperature rise of at least 20° F. or above.