Hot Air Gas Turbine Mg2 for electricity production

At Stora Enso Fine Paper Nymölla Mill there is a wish to reduce its dependency on external produced electric power. One suggestion that has been made is to install a hot air gas turbine. The purpose of this thesis is to see if it is thermodynamic and economical to go through with the project with the hot air gas turbine. It is of great importance that the boiler-process remains as unchanged as possible. The effect of higher approach temperature to the turbine has been studied to see the increase of generated electricity. A total income analysis has been calculated. It takes into consideration how revenue depends on the mixture of fuel, which has to be added for maintenance of existing steam production. Studies of the common gas turbine cycle show that the net work that is being generated is dependent on the admission temperature to the turbine, pressure ratio and work medium. How effectively the heat can be transferred from the flue gas to the air in the gas turbine cycle is of great importance. By adding heat after the super heater there seems to be an optima about 700 °C. At higher temperature the ratio between increase of generated electric power and sacrifice of fuel is decreasing. We can establish that a higher admission temperature generates more electric power even if it is more expensive over the optima. The study clearly shows increasing revenues when the proportion of bio fuel to extra heat addition is increasing.