Differences between plate heat exchangers and shell and tube heat exchangers

2. Classification of plate heat exchangers:
(1) Plate heat exchangers are compact heat exchangers based on the heat exchange area per unit space, mainly compared to shell and tube heat exchangers. Conventional shell and tube heat exchangers occupy a large space.
(2) According to the process purpose, there are various names: plate heater, plate cooler, plate condenser, and plate preheater.
(3) According to the process combination, it can be divided into two types: unidirectional plate type and multi-directional plate type.
(4) According to the flow direction of the two media, they can be divided into parallel plate heat exchangers and reverse flow plate heat exchangers. The latter is more commonly used.
(5) According to the clearance size of the runner, it can be divided into two types: plate with wide clearance and plate with wide clearance.
(6) Plate heat exchangers have detailed differences and cannot be repeated. Please refer to the ripple form of plate heat exchangers.
(7) According to whether it is a group of overall products, it can be divided into two types: single panel and panel.
3. Characteristics.
1. Characteristics of shell and tube heat exchangers:
(1) High thermal efficiency, with a thermal conductivity coefficient of 6000-8000W/(m2 · k).
(2) Made of all stainless steel, with a lifespan of up to 20 years.
(3) Converting laminar flow into turbulence can improve heat transfer efficiency and reduce thermal resistance.
(4) Rapid heat conduction, high temperature resistance (400 ℃), high pressure resistance (2.5 MPa).
(5) Compact structure, small footprint, light weight, easy installation, and saving on civil engineering investment.
(6) Flexible design, complete specifications, practicality, and cost saving.
(7) Widely applicable, suitable for pressure, temperature range, and heat exchange of different media.
(8) Low maintenance cost, easy operation, long cleaning cycle, and easy cleaning.
(9) Nano hot film technology can significantly improve the heat transfer coefficient.
(10) Widely used in fields such as thermoelectric, industrial and mining, petroleum and chemistry, urban central heating, food and medicine, energy electronics, mechanical light industry, etc.
(11) Copper tubes rolled with heat dissipation fins on the outer wall of heat exchange tubes have high thermal conductivity and large heat transfer area.
(12) The guide plate guides the continuous flow of shell side fluid through the broken line of the heat exchanger. The distance between the guide plates can be adjusted according to the flow rate. Its structure is sturdy and can meet the heat transfer requirements of shell side flow with large or even super large flow rates and high pulsation rates.
(13) Shell side liquids are oily and suitable for low viscosity, clean heat transfer oils.

2. Characteristics of plate type Teflon heat exchanger:
(1) High thermal conductivity.
Because different corrugated plates are reverse, forming a complex channel, which makes the fluid between corrugated plates flow in three-dimensional rotating flow, while turbulence will occur at a low Reynolds number (Re=50-200), so the heat conductivity coefficient is high. Generally, the red color is 3-5 times of the shell and tube type.
(2) The logarithmic average temperature difference is large, and the end temperature difference is small.
In shell and tube heat exchangers, there are two types of flow in the tube section and tube section. Generally, they are transverse flow, and the correction coefficient of Logarithmic mean temperature difference is very small. Plate heat exchangers are mostly parallel or countercurrent, with a correction factor generally around 0.95. In addition, the flow of cold flow and heat flow in the plate heat exchanger is parallel.
The hot surface and no bypass make the temperature difference at the end of the plate heat exchanger small, usually below 1 ℃ for shell and tube heat exchangers, while below 5 ℃ for shell and tube heat exchangers.
(3) Less land occupation.
The plate heat exchanger has a compact structure and a heat transfer area per unit volume that is 2-5 times that of a shell and tube heat exchanger. Unlike shell and tube heat exchangers, it does not require repair parts for extracting tube bundles. In this way, the occupied area of the plate heat exchanger is approximately 1/5-1/8 of that of the shell and tube heat exchanger, in order to achieve the same heat transfer capacity.
(4) It is convenient to change the heat exchange area or combination.
Simply adding or reducing a few hot plates can achieve the goal of increasing or reducing the heat exchange area. For the heat exchange area of shell and tube heat exchangers, the required process combination can be achieved by changing the plate layout or replacing multiple plate types. It is almost impossible to increase the heat transfer area of shell and tube heat exchangers.
(5) Lightweight.
The plate thickness of plate heat exchangers ranges from 0.4 to 0.8mm, while the thickness of shell and tube heat exchangers ranges from 2.0 to 2.5mm. Shell and tube heat exchangers have a heavier skeleton than plate heat exchangers. Plate heat exchangers usually only account for about 1/5 of the weight of the tube shell.
(6) The price is low.
Plate heat exchangers have the same material and heat exchange area, and are 40% to 60% cheaper than shell and tube heat exchangers.
(7) Easy to manufacture.
After stamping and processing, the heat transfer plate of the plate heat exchanger has a high degree of standardization and can be produced on a large scale. Shell and tube heat exchangers are usually handmade.
8) Easy to clean.
After loosening the pressure bolt on the plate heat exchanger tube bundle, the plate heat exchanger tube bundle can be loosened and disassembled for mechanical cleaning. This method is suitable for heat exchange processes that require frequent cleaning of equipment.
9) Low heat loss.
In a plate heat exchanger, only the shell plate is in contact with the heat exchange plate, and the heat loss can be ignored without the need for insulation measures.