In a combined steam-gas turbine plant, which of the following statements may apply?

In a combined steam-gas turbine plant, all the listed statements can apply due to the integrated operation of the steam and gas turbines, which enhances overall efficiency.

The air compressor plays a crucial role by providing compressed air that can be utilized in various processes, including the combustion process in the boiler. This is beneficial in improving combustion efficiency and can help to optimize the performance of the steam-generating system.

The gas turbine can exhaust hot gases that contain residual energy after generating electricity. These exhaust gases can be directed to the boiler, where they can be used to preheat water or contribute to steam generation. By utilizing the waste heat in this way, the system increases thermal efficiency and reduces the fuel required for combustion in the boiler.

The boiler can also deliver hot gases back to the gas turbine. This is particularly relevant in some configurations where the steam generated can be used to augment the energy recovery in the gas turbine section, contributing to even higher thermal efficiency. This transfer of heat creates a synergistic relationship between the steam and gas cycles, allowing for improved overall performance of the plant.

Due to these interconnected functions, all the aforementioned statements effectively illustrate how various components within a combined steam-gas turbine plant can work together to maximize energy efficiency and output.