Novel energy saving technologies for thermodynamic systems with carbon neutrality goal

Abstract

To ensure carbon neutrality goal, coal-fired power plants will have to take responsibility of deep peak regulation, which is essential to the development of renewable energy power. The penalty for deep peak-regulating operation of coal-fired power units could be more than 40 g/kW h of the net coal consumption rate (NCCR), which is contracted to the adoption of renewable energy power. Hence, in order to identify promising energy saving directions, a distribution of exergy losses in thermodynamic systems of several typical large coal-fired power units is studied in this work. For reference, systematic investigations into related conventional energy saving technologies are conducted, which consider thermodynamic interactions among the components. As a result, three novel technologies are proposed to minimize the exergy loss of the units on the deep peak-shaving condition. Based on the performed feasibility study of these technologies, it is found that: (1) using novel steam governing method on the part-load conditions offers ∼5.5 g/kW h energy saving potential; (2) in the winter season, reducing the back pressure of a dry cooling unit from 15 to 4 kPa at partial load can reduce the NCCR by ∼15 g/kW h; and (3) adopting the efficient heat-supply technology based on pressure matching would provide a NCCR reduction potential of ∼6.2 g/kW h. These new solutions, due to their energy saving effect, positive environmental impact, and cost-effectiveness, forge a synergetic development path of coal-fired and renewable energy power generations under the carbon neutrality target.