JP2009250233A - Suppression of gas turbine inlet temperature during under frequency events and related method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for augmenting power output in a gas turbine electrical power-generating plant including a multistage compressor, a combustor and a multistage turbine component, during events when grid frequency drops below a prescribed target frequency. <P>SOLUTION: This method is carried out by (a) a step of providing a liquified air source arranged to selectively add liquified air to an ambient air inlet to the compressor 12, and (b) a step of making the liquified air of controlled amount flow into the ambient air inlet during such events. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to operation of a gas turbine, and more particularly to operation of a gas turbine during an underfrequency event when demand exceeds supply.

  When the power demand exceeds the supply to the distribution network (grid), the grid frequency will drop below the target value of either 50 Hz or 60 Hz. In the case of a gas turbine-based power plant, the power generation capacity of the gas turbine decreases with decreasing frequency. Therefore, to obtain grid stability during large frequency reductions, the output of the gas turbine power plant may need to be increased at least temporarily. The output of the gas turbine used to generate electricity can be increased by, for example, additional compressor mass flow or additional fuel flow. However, the increase in compressor mass flow may be limited due to compressor surge margins or other limits, while the increase in fuel flow will reduce component life resulting from operation above normal operating temperatures. May be limited due to problems.

US Pat. No. 4,354,565

Ohasi Yoshihito, "Liquid Air Storage System to Boost Gas Turbine Capacity", Science Links Japan, http://sciencelinks.jp/j-east/article/200216/000020021602A0608919.php, Vol. 8th., Pp, 349-352 ( 2002) (Abstract only) "Heat Transfer-Asian Research", http://www3.interscience.wiley.com/journal/72507742/abstract, Wiley InterScience, Vol. 29 Issue 5, 347-357 (2002) (Abstract Only)

  Thus, the gas turbine during a short underfrequency event without the need to burn the turbine above the normal operating temperature to meet the requirements or with minimal increase in combustion temperature. There is a need for a mechanism that can enhance the output.

  According to an exemplary but non-limiting embodiment of the technology described herein, a reduction in compressor inlet temperature generally takes advantage of the known phenomenon of increasing gas turbine output performance. Yes. Thus, in an event such as when the grid frequency drops below a predetermined target frequency, in a gas turbine power plant (or other mechanical drive application) that includes a multi-stage compressor, combustor and multi-stage turbine components A method is provided for enhancing the output, the method comprising: a) a liquid or liquefied air or gas blend source (and thus simply arranged) to allow selective addition of liquid air to the ambient air inlet to the compressor. B) providing a controlled amount of liquid air in the ambient air inlet during such an event.

  In another aspect, the invention relates to a gas turbine power plant, the gas turbine power plant receiving a multi-stage compressor having an ambient air inlet, a multi-stage turbine component, pressurized air from the compressor, and a plurality of A combustor arranged to supply gaseous combustion products to the stage turbine component and a liquid air source arranged to supply liquid air to the ambient air inlet of the compressor.

  The invention will be described with reference to the single drawing figures identified below.

1 is a simplified schematic diagram of a gas turbine plant incorporating a compressor inlet cooling configuration according to an exemplary but non-limiting embodiment of the present invention. FIG.

  Referring to the figure, a gas turbine plant 10 includes a multi-stage compressor 12 that supplies air to a combustor 14, which in turn supplies hot combustion gases to a multi-stage gas turbine 16. . As shown, the compressor 12 and the gas turbine 16 operate on a common rotor shaft 18, and the rotor shaft 18 may also be coupled to a generator (not shown) disposed downstream of the turbine 16. it can. Other turbine configurations can also benefit from the present invention. The gas turbine configuration itself is not the subject of the present invention and need not be described in any further detail.

According to an exemplary but non-limiting embodiment of the present invention, a substantially open end inlet plenum 20 is disposed with respect to the compressor 12 to supply cold intake air to the compressor inlet 22. . The storage tank 24 is arranged to supply liquid air through a conduit 26 to an injection manifold 28 having a plurality of nozzles 30. Liquid air is air that has been cooled to a very low temperature by compression and heat removal. Liquid air has a density of about 870 kg / m ³ and this density can vary depending on the elemental composition of the air. Liquid air injection is controlled by a control valve 32 located in the conduit 24 upstream of the manifold 28 and nozzle 30.

  The arrangement of the manifold 28 and associated nozzles 30 can vary within the plenum 20. For example, by placing the nozzle in close proximity to the plenum inlet 34, a more uniform temperature can be achieved as the air flows toward the compressor inlet 22, but a somewhat undesired temperature rise along the passageway. May occur. Placing the manifold 28 and associated nozzle 30 in close proximity to the compressor inlet 22 can result in a colder but less uniform temperature. Thus, the exact placement of manifold 28 and nozzle 30 will depend on the particular application, which is well known to those skilled in the art.

  The inlet configuration described above allows for short-term power augmentation by injecting liquid air into the inlet system of the compressor 12 thereby lowering the temperature of the ambient air entering the compressor 12. A decrease in temperature by increasing the flow rate of liquid air will increase the output of the gas turbine 16 to a level that will at least temporarily require the gas turbine 16 to burn above its normal operating temperature. Let

  The control scheme can be based on power requirements at various frequency levels or on maintaining a specific compressor inlet temperature. Valve 32 provides the liquid air supply to the minimum required to maintain the required output at a given frequency level, ie, based on intermittent or regulated criteria that saves expensive liquid air as a longer refill interval. Controlling can also provide benefits.

  It should also be understood that compressor surge and component life can be improved by the power enhancement achieved by the additional compressor mass flow as described herein.

  Although the present invention has been described with respect to what is considered to be the most practical and preferred embodiments at the present time, the invention is not limited to the disclosed embodiments, and conversely, It should be understood that various modifications and equivalent arrangements included within the technical scope are intended to be protected.

DESCRIPTION OF SYMBOLS 10 Gas turbine plant 12 Multiple stage compressor 14 Combustor 16 Multiple stage gas turbine 18 Rotor shaft 20 Inlet plenum 22 Storage tank 26 Conduit 28 Manifold 30 Nozzle 32 Control valve 34 Plenum inlet

Claims (11)

Multi-stage compressor, combustor and multi-stage turbine configurations during events such as when the grid or gas turbine frequency drops below a predetermined target frequency or when the gas turbine load is predicted to temporarily exceed its capacity A method for enhancing power in a gas turbine power plant including an element, comprising:
a) providing a liquid air source arranged to allow selective addition of liquid air to an ambient air inlet to the compressor;
b) flowing a controlled amount of liquid air into the ambient air inlet during the event.   The method of claim 1, comprising providing one or more control valves in a conduit that supplies the liquid air to the ambient air inlet.   The method of claim 2, wherein step b) includes injecting the liquid air through a plurality of nozzles installed in close proximity to an ambient air inlet of the compressor. Said step b)
Attaching the nozzle to a manifold;
Installing the manifold in the plenum adjacent to the ambient air inlet;
The method of claim 3.   The method of claim 1, wherein step b) is performed as a function of the grid frequency.   The method of claim 1, wherein step b) is performed as a function of compressor air inlet temperature and turbine power.   The method of claim 1, wherein step b) is performed to provide a minimum amount of liquid air to maintain the required power at a predetermined frequency level. A multi-stage compressor having an ambient air inlet;
A multi-stage turbine component;
A combustor arranged to receive pressurized air from the compressor and to supply gaseous combustion products to the multi-stage turbine component;
A gas turbine power plant including a liquid air source arranged to supply liquid air to an ambient air inlet of the compressor.   The gas turbine power plant according to claim 8, comprising a liquid air injection manifold with one or more injection nozzles installed proximate to the ambient air inlet. A conduit disposed between the liquid air source and the ambient air inlet;
A control valve is installed in the conduit upstream of the manifold;
The gas turbine power plant according to claim 9.   The gas turbine power plant of claim 10, wherein the manifold is installed in a plenum adjacent to the ambient air inlet.

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