High pressure ratio twin spool industrial gas turbine engine

Abstract

An industrial gas turbine engine for electrical power production includes a high pressure spool and a low pressure spool in which the low pressure spool can be operated from full power mode to zero power mode when completely shut off, where the low pressure spool is operated at high electrical demand to supply compressed air to the high pressure compressor of the high pressure spool, and where turbine exhaust is used to drive a second electric generator from steam produced in a heat recovery steam generator. The power plant can operate at 25% of peak load while keeping the unused parts of the power plant hot for easy restart when high power output is required.

Description

field of invention [0001] The present invention relates generally to industrial gas turbine engines (note: also referred to as "gas turbines"), and more particularly to dual rotor industrial gas turbine engines having a low pressure rotor that can be operated independently of a high pressure rotor. Background of the invention [0002] In a gas turbine engine, such as a large-frame heavy-duty industrial gas turbine (IGT) engine, a flow of hot gas generated in a combustor passes through a turbine to produce mechanical work. A turbine includes one or more rows or stages of stator vanes and rotor blades that react with hot gases at progressively lower temperatures. The turbine, and thus the efficiency of the engine, can be increased by passing higher temperature gases through the turbine. However, the turbine (note: aka "turbine") inlet temperature is limited by the material properties of the turbine, especially the first stage guide vanes and blades, and the amount of cooling ...

AI Technical Summary

Problems solved by technology

[0009] The setup of Figure 15 is the most efficient option in the current configuration for IGT engines, but is not optimal because the low rotor shaft 6 rotates within the high rotor shaft 5, and thus the high rotor shaft radius cannot be further reduced

Also, if the speed of the low rotor shaft 6 is reduced to reduce the inlet mass flow, there is a mismatch in the angle from the HPT (high pressure turbine) into the LPT (low pressure turbine), and out of the LPT (low pressure turbine) and into the PT (power turbine) mismatch of flow angles, resulting in inefficient turbine performance at part load

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