The recovery and utilization methods of flue gas waste heat can be divided into three situations: direct utilization, indirect utilization and comprehensive utilization.
1. Direct utilization: refers to the direct application of high-temperature heat energy in flue gas to the process. The common direct utilization method is flue gas preheating, which uses the heat energy in flue gas to preheat the air or fuel entering the boiler or furnace, thus reducing fuel consumption.
2. Indirect utilization: Indirect utilization refers to converting heat energy in flue gas into other forms of energy, and then applying it to the process. Common indirect utilization methods are: gas power generation uses heat energy in flue gas to generate electricity, and heat energy is converted into mechanical energy through gas turbine or steam turbine, and then into electrical energy.
Benefits of flue gas waste heat recovery: 3. Comprehensive utilization: Comprehensive utilization refers to multi-level and multi-form energy conversion and utilization of heat energy in flue gas. The common comprehensive utilization method is flue gas waste heat recovery system, which transfers the heat energy in flue gas to other media, such as water, steam or thermal media, to realize energy transfer and utilization. The application of flue gas waste heat recovery technology can effectively reduce energy consumption and environmental pollution and achieve the goal of sustainable development. When selecting the recovery method of flue gas waste heat, factors such as process characteristics, energy demand and economic benefits should be considered comprehensively.