Finned Tube Exhaust Gas Heat Exchangers for Cogeneration Power Plants

Finned Tube Exhaust Gas Heat Exchangers for Cogeneration Power Plants

Finned tube exhaust gas heat exchanger is a kind of equipment used to recover the waste heat of exhaust gas in the process of cogeneration.

Structural Design

Base Tube: Mild steel or stainless steel tubes are usually used. Low cost, good toughness, excellent processing performance, mild steel can provide solid support in the general pressure environment; stainless steel tube has excellent corrosion resistance, suitable for corrosive media in complex environments.

Fin: mostly aluminum, because of its high thermal conductivity, can quickly conduct heat. The fins have various shapes, the common ones are spiral, flat and corrugated. Spiral fins can change the direction of fluid flow, extend the flow distance and increase the heat transfer area; straight fins have a simple structure and are suitable for scenarios with regular space layout requirements; corrugated fins can disrupt the fluid flow state and enhance the heat transfer efficiency.

Connection: The fins and the base tube are closely connected by high-frequency welding, roll forming and roll molding, which effectively reduces the contact thermal resistance and ensures that the heat can be rapidly transferred from the hot fluid inside the tube to the cold fluid outside.

Working Principle

Heat Conduction: When the hot fluid (such as the high temperature exhaust gas generated in the process of cogeneration) flows inside the tube, the heat is first transferred from the hot fluid to the inner wall of the base tube by heat conduction, and then passes through the wall of the base tube to the outer wall.

Convective heat transfer: The fins, which are closely combined with the outer wall of the base tube, absorb the heat from the steel tube. When a cold fluid (such as water or air) flows through the fins, the heat is transferred to the cold fluid through convective heat transfer, thus realizing the exchange of heat between the hot fluid and the cold fluid. The presence of fins increases the heat transfer area, and their shape and arrangement create turbulence in the fluid, greatly enhancing the heat exchange process.

Advantages

Highly efficient heat transfer: Expanding the heat transfer area by adding fins significantly improves the heat transfer efficiency, which enables more effective recovery of waste heat from exhaust gases and improves the energy utilization rate of cogeneration power plants.

Compact structure: taking up little space, it can be laid out more flexibly in the limited space of the power plant, which helps to improve the overall space utilization rate of the power plant.

Strong adaptability: According to different exhaust gas temperatures, flow rates, compositions and different cold fluid requirements, suitable base tube materials, fin forms, fin spacing and other parameters can be selected to adapt to a variety of complex working conditions.

Good corrosion resistance: when elected stainless steel base tube and fin material with certain corrosion resistance, it can resist the erosion of corrosive components in the exhaust gas to a certain extent and extend the service life of the equipment.

Application Scenario

Waste Heat Recovery of Exhaust Gas: It is used to recover the waste heat from the exhaust gas discharged from the boiler and the exhaust gas from the gas turbine, etc. The recovered heat is used to preheat the boiler feed water, to heat the water for domestic use, or to meet the heating demand in other industrial production processes, so as to minimize the energy consumption and reduce the operation cost.

Air preheating: The heat in the exhaust gas can be transferred to the air used for combustion, increasing the air temperature, making the fuel burn more fully, improving combustion efficiency and reducing pollutant emissions.

Steam production: The waste heat of exhaust gas is used to heat water to produce steam for power generation, industrial production or heat supply, etc., increasing the steam production of the power plant and improving the comprehensive benefits of cogeneration.