Feasibility study of the energy and economic gain that can be achieved by driving the boiler feedwater pump with a backpressure steam turbine

Abstract

The low-pressure steam requirement in the iron and steel production plant is obtained through pressure reduction stations with unrestrained expansion. In this study, the feasibility of obtaining the low-pressure steam that is needed in the plant in a backpressure turbine instead of pressure reduction stations has been studied. In this way, it is foreseen that a significant amount of wasted energy during the unrestrained expansion in pressure reduction stations, can be recovered as shaft work during the expansion process performed in the turbine. The obtained shaft work is planned to be used in the boiler feedwater pump drive. It is aimed to increase the efficiency of the system by the deactivation of boiler feedwater pump electric motors and as well as bringing the energy that is lost during the unrestrained expansion of the superheated steam to the system through the pump drive. The estimated size of energy saving of the system could be reached to 33.74%. The annual size of achievable saving has been determined by approximately 8,094,810 kWh and economically $509,973. The payback period of the estimated $683,079 investment is 1.34 years. A determined amount of saving is also equivalent to the reduction of 7,285,329 kg CO2 emission, annually.

The influence of various optimization algorithms on nuclear power plant steam turbine exergy efficiency and destruction

“…Steam turbine operation in various power plants strongly differs. They can dominantly operate by using wet or superheated steam [23,24], they can be composed of one or more turbine cylinders [25,26], turbine cylinders can be single flow or dual flow (while dual flow cylinders can be symmetrical or asymmetrical) [27], turbine cylinders can be connected to the same or to the various shafts [28,29], steam turbines are nowadays dominantly composed of many stages (however, still in exploitation can be found steam turbines with only one stage used for various auxiliary purposes) [30,31], turbine stages can be of impulse, reaction or Curtis type [32], temperature and pressure of steam delivered to any steam turbine can significantly vary [33,34]. Therefore, observations which pointed out that any steam turbine operates in a same manner is valid only in the most general and overall form.…”