The plate heat exchanger uses a corrugated plate as a heat transfer surface. The flow path is covered with mesh contacts. The fluid flows along the narrow curved and labyrinth channels between the plates. The speed and direction change continuously to form strong turbulence.Thereby destroying the boundary layer, reducing the thermal resistance of the interface liquid film, suspending solid particles, not easily depositing, effectively strengthening heat transfer.Therefore, it has many unique advantages over other types of heat exchangers such as shell and tube.
(1) The heat transfer coefficient is high. Due to the special structure and assembly mode of the plate heat exchanger, the flow direction and flow velocity are constantly changed when the medium flows through the passage between the adjacent plates, and a sharp turbulence is formed at a low flow rate to enhance heat exchange.The total heat transfer coefficient K of the plate heat exchanger is 2330 to 5810 W/( m2 ·K), and the highest is 6980 to 8150 W/( m2 ·K).It is 2 to 3 times higher than the shell-and-tube heat exchanger K = 1400 to 2790 W/( m2 · K). Under the same pressure loss, the heat transferred by the plate heat exchanger is 6 to 7 times that of the shell-and-tube heat exchanger.
(2) The temperature difference is small. Due to the high heat transfer coefficient and strong turbulence of the plate heat exchanger, the temperature of the primary and secondary fluids of the heat exchanger is very close, and the temperature difference approaches 1 to 3 ℃
(3) The heat loss is small. Since the edge of the slab and the gasket are exposed to the atmosphere, the heat loss is minimal (1%) and no insulation measures are required. In the case of the same heat exchange area, the heat exchange loss of the plate heat exchanger is only 1/5 of the shell-and-tube heat exchanger.