The economy of the power plant could be effectively improved by the deep utilization of waste heat. Several types of waste heat utilization methods at home and abroad were reviewed, including the conventional waste heat utilization method and several new methods, such as heat ex-changer grading, bypass flue technology and heat pump technology. A detailed comparison of the energy-saving effects of different waste heat utilization methods was conducted. It is considered that the heat recovered from conventional low-temperature economizer flue gas is relatively limited. The graded waste heat utilization can be achieved by the hierarchical method. The bypass flue technology is more economical because of the displaces of extraction from higher-grade steam turbines. The energy quality can be further enhanced by the heat pump technology.
