| EP2136051A2 | 2009-12-23 |
| THE CLAIMS 1. I claim by this invention that, the process characterized by reducing compressor load consumption of a gas turbine by injecting relatively cold high pressure water into the compressor in order to reduce its air outlet temperature and pressure safely above saturation point before leaving the compressor in order to increase gas turbine overall efficiency is my sole invention. 2. I claim by this invention that, the process characterized by maximizing gas turbine mass flow by adjusting the temperature of the high pressure water being injected into the compressor and mentioned in claim (1) in order to further increase the improvement in gas turbine overall efficiency is my sole invention. |
| AMENDED CLAIMS received by the International Bureau on 31 October 2013 (31.10.2013) 1- A process characterized by reducing load consumed by gas turbine compressor to improve gas turbine overall efficiency and, to maximize mass flow rate to further improve gas turbine overall efficiency. 2- As air at compressor outlet is superheated, therefore to reduce load consumed by gas turbine compressor in claim 1, air at compressor outlet is to be de- superheated safely to steam saturation line for the compressor. 3- The process of claim 2 can be achieved by injecting water/fluid at ambient temperature into the last stages of the compressor to accomplish the required degree of air de-superheat. 4- To further improvement in gas turbine overall efficiency in claim I, mass flow rate of the water/fluid being injected into the last stages of the compressor is to be maximized. 5- Maximizing mass flow rate in claim 4 can be obtained by rising water/fluid temperature being injected from ambient temperature towards steam saturated line temperature or above for the compressor, to accomplish the required degree of air de-superheat. I claim by this invention that all above mentioned clams (1-5) are my sole inventions. |
TITLE OF THE INVENTION
Reducing the load consumed by gas turbine compressor and maximizing turbine mass flow
TECHNICAL FIELD
This invention is applicable to industrial gas turbines, and looking into reducing the load consumed by gas turbine COMPRESSOR and maximizing turbine MASS FLOW.
BACKGROUND ART
Improving gas turbines overall efficiency efforts have no limit, and more efforts are taking placed in this field, as this will lead to increase in power generated by gas turbine and reduces fuel consumption for that power.
STATEMENT OF THE PROBLEM
The main problem avoiding gas turbine overall efficiency improvement is that, air compressor alone consumes most of the power being generated by the turbine. Moreover gas turbine air mass flow cannot be maximized without increasing compressor load consumption.
INVENTION DISCLOSER
From example below and from steam table, it can be seen that air at compressor outlet is superheated. Excess superheating increases compressor load consumption. Therefore reducing compressor air outlet temperature and pressure safely above saturation point before leaving the compressor will reduce compressor load consumption, and will increase gas turbine overall efficiency. This can be done by injection high pressure water relatively cold into air compressor as shown in drawing (1).
Moreover, gas turbine mass flow rate can be maximized by increasing the temperature of the high pressure water being injected into the compressor as shown in the example. Increase in gas turbine mass flow will further increase gas turbine overall efficiency.
The drawing shows gas turbine main parts, air compressor, combustion chamber, turbine, electrical generator, and high pressure water injection system.
METHOD OF IMPLEMENTATION For invention implementation, High-pressure water injection system to be introduced to the gas turbine. At compressor last stages, High-pressure injectors to be hosted between the stationary compressor blades. The high pressure nozzles are to be connected to high pressure water system. Means of controlling the temperature of the high pressure water being injected into the compressor is essential.
DESCRIPTION OF ONE SPECIFIC EXAMPLE OR EMBODIMENT OF THE INVENTION
For a Gas turbine having the followings:-
Tl: Compressor-air inlet temperature °K = 283 °K
T2: Compressor-air outlet temperature °K = 547 °K
P2: compressor air outlet pressure = 12 bar
T3: Gas turbine inlet temperature °K = 1258 °K
T4: Gas turbine outlet temperature °K = 768°K
r|ad: adiabatic efficiency
CALCULATION
1 st : improving gas turbine efficiency by reducing energy
consumed by air compressor.
From steam table the following can be extracted:
Water vapor at 12 bar and compressor outlet temperature of (274 °C) = 547 °K is in the superheated zone.
Saturation Temperature = 192 °C = 465°K
Degree of Superheat = 547 - 465 = 82 degree
Therefore compressor air outlet temperature can be reduced by 70 degrees from 547 °K to 477 °K without de- superheating it.
Turbine adiabatic efficiency ad = 1- (T4-T1)/(T3-T2) .. (Brighton cycle) The adiabatic efficiency of the gas turbine ad = 32 %
Table below shows the improvement in the adiabatic efficiency from 32 % to 38 % in relation to drop in compressor outlet temperature from 547 °K to 477 °K. 2 nd : Improvement gas turbine overall efficiency by increasing turbine mass flow.
From gas turbine overall thermal efficiency equation where
r|t : Turbine thermal efficiency
Wt: Work done by gas turbine = (Ma + Mf) (h3 - h4)
Wc: Load consumed by compressor = Ma (h2 - hi)
h: air specific heat
Ma: Air mass flow rate from compressor
Mf: Fuel mass
Mw: Mass of high pressure water injected in compressor r|t = [(Wt - Wc)/Wt] x 100 = 1- [ Ma(h2-hl)/Ma+Mw+Mf (h3-h4)] x 100
From the above equation it can be seen that the increase in injected water mass (Mw) will increase gas turbine overall efficiency.
3 : Improving gas turbine overall efficiency by maximizing turbine mass flow.
From fluid mixture equation
Taw = (Ma Ta + Mw Tw)/(Ma+Mw)
Therefore Mw = Ma (Ta - Taw)/(Taw - Tw)
Where :-
Taw: Required air water mixture temperature = 477 °K
Ta: Compressor air outlet temperature = 547 °K
Tw: Injected water temperature = 288 °K
Mw/Ma = Water mass to air mass
Therefor the required mass of high pressure water injected to reduce compressor outlet temperature from 547 °K to 477 °K is Mw = 0.37 Ma
The below table shows the increase in injected water mass rate in relation to air mass flow rate corresponding to increase in injected water inlet temperature.
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