Life cycle energy use efficiency and greenhouse gas emissions of circulating fluidized bed coal-fired plant with coal gangue and coal co-combustion

Few studies explore the ideal co-combustion ratios of gangue and coal and improve CFB power generation technology. Here, we use life cycle assessment to establish a model to evaluate greenhouse gas (GHG) emissions and energy use efficiency (EUE) of a circulating fluidized bed (CFB) coal-fired plant with gangue and coal co-combustion technology. The life cycle includes coal mining, coal washing and power generation. The functional unit is 1 MWh electricity output. Considering the different fuel components of coal and coal gangue, we conduct six scenarios with coal mass ratio of 0%, 10%, 20%, 30%, 40%, and 50% in the mixed fuel, respectively. The results show that the increase in the proportion of coal will lead to the decrease in GHG emissions. The scenario with pure gangue has the highest GHG emission of 1105 kg CO 2 eq/MWh, while the scenario with 50% coal has the lowest GHG emission of 956 kg CO 2 eq/MWh. Among all GHGs, CO 2 contributes the largest GHG emissions. The power generation is the main source of GHG emissions. Overall, the ultra-low emission of N 2 O ensures that CFB power generation technology has the advantage of low GHG emissions. The EUE will increase with the coal mass ratio increases. The scenario with pure gangue has the lowest EUE of 34.0%, while the scenario with 50% coal has the highest EUE of 35.5%. Fuel consumption and plant auxiliary power consumption are the main energy inputs. Finally, we provide the ideal co-combustion coal mass ratio of 20% to 30% and suggest some corresponding measures to reduce GHG emissions and improve EUE simultaneously.