Abstract:

Supercritical CO₂ cycle can be used in the low temperature scenario to reduce the end temperature of the cycle and increase the cycle pressure ratio, which can well match with the coal-fired boiler to form a high-efficiency coal-fired power plant. Considering the climate and coal mine distribution, the coal mine bases in northern China, such as eastern Inner Mongolia and northern Xinjiang, have low atmospheric temperature conditions for more than four months in winter and spring, which is good for the constrution of high-efficiency supercritical CO₂ coal-fired power plants. For the end temperature condition of 3-15 ℃, the thermodynamic calculation of supercritical CO₂ cycle was carried out, and the economic and social benefits of the unit were analyzed. The results show that the supercritical CO₂ cycle generator with 620 ℃/30 MPa initial parameters can obtain more than 48% of the net plant power generation efficiency in the low temperature scenario below 9 ℃, which is expected to surpass the efficiency of double-reheat ultra supercritical steam turbine unit. Supercritical CO₂ cycle coal-fired power plants can supplement the power generation gap of renewable energy generation in winter and spring, and realize the efficient utilization of coal resources in the north through “North to South Power Transmission”.

Key words: supercritical CO₂ cycle, coal-fired power generation, low temperature environment