Compressed air energy system integrated with gas turbine
View Patent ↗An apparatus performs a power cycle involving expansion of compressed air utilizing high pressure (HP) and low pressure (LP) air turbines located upstream of a gas turbine. The power cycle involves heating of the compressed air prior to its expansion in the HP and LP air turbines. Taking into consideration fuel consumption to heat the compressed air, particular embodiments may result in a net production of electrical energy of ˜2.2-2.5× an amount of energy consumed by substantially isothermal air compression to produce the compressed air supply. Although pressure of the compressed air supply may vary over a range (e.g. as a compressed air storage unit is depleted), the gas turbine may run under almost constant conditions, facilitating its integration with the apparatus. The air turbines may operate at lower temperatures than the gas turbine, and they may include features of turbines employed to turbocharge large reciprocating engines.
1. A method comprising:
providing a thermal power plant operating on a steam Rankine cycle and including a boiler, a steam turbine, and steam feed water from a condenser and configured to be heated by steam bled from the steam turbine;
providing energy from an external energy source to a gas compression process;
storing compressed gas from the gas compression process in a compressed gas storage unit;
communicating thermal energy from the gas compression process to heat the steam feed water, wherein the thermal energy is communicated from an aftercooler of a gas compressor;
flowing the steam feed water to the boiler;
providing an existing gas turbine of single shaft design that has been modified to remove compressor blades to obtain a compressorless gas turbine;
flowing compressed gas from the gas compression process to a turbine comprising an air turbine in communication with the compressorless gas turbine; and
heating the compressed gas with a combustion product of an output of the compressorless gas turbine.
2. A method as in claim 1 wherein the gas compressor comprises a reciprocating member.
3. A method as in claim 1 wherein the thermal energy is communicated from an intercooler of a gas compressor.
4. A method as in claim 3 wherein the gas compressor comprises a rotating member.
5. A method as in claim 3 wherein the gas compressor comprises multiple reciprocating stages.
6. A method as in claim 1 further comprising storing the thermal energy.
7. A method as in claim 1 wherein the external energy source comprises a renewable energy source.
8. A method as in claim 7 wherein the renewable energy source is intermittent.
9. A method as in claim 7 wherein the renewable energy source comprises wind.
10. A method as in claim 7 wherein the renewable energy source comprises solar.
11. A method as in claim 7 wherein the renewable energy source provides the energy off-peak.
12. A method as in claim 1 wherein the thermal power plant involves combustion.
13. A method as in claim 1 wherein the thermal power plant involves a nuclear reaction.
14. A method as in claim 1 further comprising storing the water in a thermal storage unit prior to flowing to the boiler.