Waste Heat Recovery from Flue Gas

Waste heat recovery from flue gas refers to the technology that captures heat from high-temperature exhaust gases emitted by industrial boilers and kilns via heat exchange equipment, and transfers it to media such as water or air for reuse.

Its core principle is based on the laws of thermodynamics and heat and mass transfer. Through indirect contact (e.g., partition-type heat exchange) or direct contact methods, it establishes an energy cycle of "emission—recovery—reuse."

Primary Applications

Recovered flue gas waste heat can be converted into thermal energy, electrical energy, or cooling energy based on specific demands:

l Direct Thermal Utilization: Preheating combustion air to reduce fuel consumption, heating process materials, or supplying hot water for industrial parks and district heating.

l Thermoelectric Conversion: Using high-temperature flue gas to generate high-pressure steam for steam turbine power generation, or employing Organic Rankine Cycle (ORC) technology to recover low-to-medium temperature waste heat for electricity generation.

l Refrigeration and Heating: Driving lithium bromide absorption chillers to provide process cooling for factories, or utilizing heat pump technology to upgrade the temperature grade of low-grade waste heat.

Typical Application Scenarios

l Iron and Steel Metallurgy: Recovering high-temperature flue gas from energy-intensive equipment such as rolling mill reheating furnaces and converters for power generation or combustion air preheating.

l Building Materials and Chemicals: Utilizing waste heat boilers to achieve energy cascade utilization from the extremely high-temperature exhaust gases of cement rotary kilns and glass melting furnaces.

l Waste Incineration: Recovering energy from high-temperature flue gas in incinerators via waste heat boilers for power generation prior to subsequent flue gas purification.