Advantages of plate type heat exchanger as follow:
(1)High heat transfer coefficient Because different corrugated plates are inverted with each other and form complicated flow path. so that the fluid flows in a three-dimensional flow in the flow path between the corrugated plates, and can be generated turbulent flow at a low Reynolds number (generally Re=50-200). so the heat transfer coefficient is high, it’s 3 to 5 times the shell-and-tube type.
(2)The logarithmic mean temperature difference is large and the terminal temperature difference is small. In the shell-and-tube heat exchanger, the two fluids flow in the tube and shell processes respectively, which is generally a cross-flow flow, and the logarithmic mean temperature difference correction coefficient is small.Plate type heat exchangers are mostly cocurrent or countercurrent flow modes, and the correction coefficient is usually about 0.95. In addition, cold and hot fluids in the plate heat exchanger is parallel to the heat exchange surface and there is no bypass flow, The temperature difference at the end of the device is small, the heat exchange for water can be lower than 1 ° C, and the shell-and-tube heat exchanger is generally 5 ° C
(3) The plate heat exchanger has a compact structure, and the heat exchange area per unit volume is 2~5 times that of the shell-and-tube type. It is not the same as the shell-and-shell type, and the maintenance site for the extracted tube bundle is reserved.
The plate heat exchanger covers an area of about 1/5 to 1/8 of the shell-and-tube heat exchanger at the same heat exchange capacity .
(4)It is easy to change the heat exchange area or process combination. As long as several plates are added or reduced, the purpose of increasing or decreasing the heat exchange area can be achieved. By changing the plate arrangement or replacing several plates, the required process combination can be achieved to fit for the new heat exchange conditions.The heat transfer area of the shell-and-tube heat exchanger is almost impossible to increase.
(5) Light weight .The thickness of th phe plate is only 0.4~0.8mm, while the thickness of the heat exchange tube of the shell-and-tube heat exchanger is 2.0~2.5mm, The shell is much heavier than phe frame, and the plate heat exchanger is only about 1/5 of the shell-shell weight.
(6)Low price with the same material, the plate heat exchanger is about 40% to 60% lower than the shell-and-tube type under the same heat exchange area.
(7) Convenient production .The heat transfer plates of the plate heat exchangers are stamped, highly standardized, and can be mass-produced. The shell-and-tube heat exchangers are hand-made.
(8) Easy to clean. The frame type plate heat exchanger can loosen the plate pack for mechanical cleaning as long as the compression bolt is loosened, which is very convenient for the heat exchange process equipment to be cleaned frequently.
(9)Small heat loss The plate heat exchanger only exposes the outer to the atmosphere, so the heat loss is negligible and no heat preservation measures are required. The shell-and-tube heat exchanger has a large heat loss and requires heat insulating layer.
(10)Smaller capacity is 10%~20% of shell-and-tube heat exchangers
(11) It is not easy to scale because the internal is fully swayed. The fouling coefficient is only 1/3~1/10 of the shell-and-tube heat exchanger.