Stainless Steel Tube-and-fin Heat Exchangers in The Sludge Drying Process

Stainless Steel Tube-and-fin Heat Exchangers in The Sludge Drying Process

The core processes of sludge drying are heat transfer and mass transfer. Heat must be efficiently transferred to the sludge to evaporate its moisture. The heat exchanger serves as the heat source here, heating air (or inert gases like nitrogen), which is then used as hot air to dry the sludge.

Stainless Steel Tube:

Core Function: Pressure resistance, corrosion resistance.

Typically carries high-temperature steam, thermal oil, or hot water. These hot media operate at elevated pressures and may be corrosive. Stainless steel (commonly 304 or 316L) provides sufficient strength and excellent corrosion resistance, ensuring pipeline safety and longevity.

Aluminum Fin:

Core Function: Enhance heat transfer, reduce weight, lower costs.

Aluminum exhibits exceptional thermal conductivity (approximately 200 W/m·K), over ten times that of stainless steel. By expanding numerous fins around the steel tube, the surface area exposed to air is significantly increased (typically with a high fin-to-tube ratio), substantially improving heat transfer efficiency on the air side.

Combination rationale: Stainless steel tubes withstand internal high pressure and corrosive heat transfer fluids; aluminum fins efficiently and economically transfer heat from the tubes to the external air. This achieves an optimal balance between performance, longevity, and cost.