Flue Gas Waste Heat Recovery Method

Flue Gas Waste Heat Recovery Method

Flue gas waste heat recovery is an energy-saving technology that reduces energy consumption by recovering heat from flue gases generated during industrial production or combustion processes and using it to heat water, steam or other purposes.

The following are some common ways of recovering waste heat from flue gas:

1. Flue gas heat exchanger

Flue gas heat exchanger is one of the most common flue gas waste heat recovery equipment. It works by installing a heat exchanger between the flue gas and the fluid to be heated (e.g., water or air), using the heat in the flue gas to heat the fluid.

Types of heat exchangers include:

Shell and tube heat exchanger: the flue gas flows through the shell of the heat exchanger tube, and the fluid inside the tube circulates inside the tube, thus achieving heat transfer.

Plate heat exchanger: flue gas and fluid are contacted through parallel arranged plate heat exchange surfaces for heat transfer.

Air preheater: It is especially used in coal-fired boilers to improve the combustion efficiency of the boiler by preheating the flue gas with air.

2. Steam regeneration

In many industrial production processes, large quantities of steam are required. Effective recovery of flue gas waste heat can be achieved by using the heat from the flue gas for steam generation. This method is widely used in boilers, power plants and chemicals.

3. Heat pipe technology

Heat pipe technology is a highly efficient heat transfer method to transfer heat from flue gas to other media. Heat pipes can be flexibly arranged and are suitable for various complex industrial environments.

4. Flue gas condensation

Waste heat recovery is carried out by using the latent heat released from the water vapour in the flue gas during condensation. This method is usually used for flue gases with high water content, e.g. coal-fired boilers.

5. Combustion air preheating

In some industrial combustion processes, combustion efficiency can be improved and fuel consumption reduced by using the heat from the flue gas to preheat the air required for combustion.

6. Flue gas power generation

This is a way of converting the heat in flue gas into electricity. Through cogeneration technology, heat from the flue gas is converted into electricity using equipment such as heat generators or thermocouples to achieve efficient use of energy.

7. Thermal Media Circulation System

Using heat medium (such as oil or salt) to transfer heat, the heat in the flue gas is transferred to the heat medium through a heat exchanger, and then the heat medium is brought back to the equipment that needs to be heated, so as to realise the recycling of heat.

8. Heat pump technology

Flue gas waste heat can be used to drive a heat pump system to provide additional heating or cooling. Heat pumps convert low-temperature heat into high-temperature heat for energy reuse.

These methods can be applied individually or in combination. The appropriate flue gas waste heat recovery technology can be selected according to different industrial production processes and needs, thus realising energy savings and environmental protection.