Electric energy generation at compressor stations using gas-turbine heat recovery plants

The article analyzes the efficiency of Brayton cycle gas-turbine heat recovery plants during electricity generation both with and without combustion of extra fuel in the heat recovery circuit. The authors derive analytical relationships for calculation of the optimal compressor pressure boost which provides the maximum specific output of the gas-turbine heat recovery plant. Without extra fuel combustion, the gas-turbine heat recovery plant increases generating the mechanical energy output from 16% to 26% at the recuperation rate from 0.8 to 0.86 and the drive unit output gas temperature from 750 K to 850 K. The optimal pressure boost providing both the maximal output and efficiency of the gas-turbine heat recovery plant as well as the combined power plant is from 3.5 to 4.5. Burning extra fuel inside the combustion chamber of the heat recovery unit increases temperature upstream of the turbine working medium. It also increases the generated mechanical energy output. With the increase in the temperature up to 800... 1100 K, the output of the combined power plant comprising the gas-turbine heat recovery and NK-14ST-10 drive plant increases up to 29...75 %; greater efficiency is provided at lower working medium heating. Specific cost of the gas-turbine heat recovery plant is lower due to less sophisticated design and low-cost construction materials of the plant units. Using the combustion chamber in the gas-turbine heat recovery plant is defined by the necessary amount of extra electrical energy.

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