Utilizing flue gas low-grade waste heat and furnace excess heat to produce syngas and sulfuric acid recovery in coal-fired power plant

To reduce fossil resource consumption and air pollution, the effective utilization of furnace's redundant heat during peak shaving period, carbon dioxide emission reduction and flue gas waste heat recovery are three significant issues for energy saving and emission reduction of coal-fired power plants. However, these three aspects are considered separately in the past. In this study, an innovative design is proposed, in which the high and medium-grade heat during peak-off period is used for methane reforming reaction heating, while the low-grade waste heat of flue gas is used as the heat source for carbon capture process. The captured CO2 is employed as feedstock of methane dry reforming reaction to produce syngas. Meanwhile, sulfuric acid is recovered from flue gas in a special heat exchanger. Results show that this design can reduce by 445132.2 tonne of CO2 every year while the max output rate of syngas's high heating value and mass are 17,777 GJ/d and 601.7 t/d (with H2/CO = 0.618). Meanwhile, it can recover H2SO4 of 14,649 t/yr. This design not only recovers the heat energy of coal-fired power plants, but also realizes the capture and utilization of CO2, which deeply embodies the concepts of energy conservation and environmental protection.