Views: 10 Author: Site Editor Publish Time: 2022-10-12 Origin: Site
Plate heat exchangers and shell and tube heat exchangers are the two most common types of heat exchangers, and they both provide a lot when you want to heat or cool wort during processing. Heat exchangers work by transferring thermal energy from one medium to another through tubes or plates. However, in certain applications, plate heat exchangers offer several advantages over shell and tube heat exchangers.
What are the basic functions of plate heat exchangers?
Plate heat exchangers have several basic functions in food, dairy, beverage, and pharmaceutical processing:
Change and maintain consistent pasteurization temperature.
Transfer heat without contaminating the heating fluid.
Energy saving is achieved by reusing the heating fluid to heat the fluid in a repeatable cycle.
Heated water and cleaning fluids for efficient clean-in-place (CIP) systems.
Accurate temperature control is achieved during the sterilization stage.
Why Breweries Choose Plate Heat Exchangers
1.Lower Pressure Drop
Because of the smaller area required for plate heat exchangers, the design total pressure drop of plate heat exchangers is usually much lower than that of shell and tube heat exchangers of the same design. This lower pressure drop increases the overall energy efficiency of the plate heat exchanger.
The heat exchange efficiency of a plate heat exchanger is five times that of a shell and tube design, so in many cases, you can utilize more heat by replacing your existing shell and tube heat exchanger with a compact plate heat exchanger.
Gasket spaces are formed between the plates in a plate heat exchanger, and these spaces alternate between two fluids—one hot and one cold. This design provides very high heat transfer efficiency because the plates create a much larger surface area than a shell and tube design that fits in the same space.
2.Heat Exchange Efficiency
Typically, plate heat exchangers are the right choice for breweries as it is the most efficient and cheapest option, and plate heat exchangers are five times more efficient than shell-and-tube designs.
A higher heat transfer coefficient can be obtained due to corrugated plate and higher speed.
Allows more heat transfer due to pure countercurrent flow and close temperature.
Higher energy recovery can be achieved due to these closer temperature methods.
Overall heat transfer coefficient
The heat transfer coefficient describes the heat energy transferred by both designs. Coefficients are multipliers in the heat transfer equation, so higher numbers mean more heat transfer. Plate heat exchangers achieve improved heat transfer coefficients while having a smaller footprint and lighter weight than shell-and -tube design heat exchangers.
|Overall Heat Transfer Coefficient - U -|
|Liquid-to-Liquid Heat Transfer||Heat Transfer Coefficient W/(m2 K)||Btu/(ft2 °F h)|
|Shell and Tube||150-1200||25-200|
|Plate and Frame||1000-4000||150-700|
High-quality plate heat exchangers can operate efficiently for ten years and require no maintenance. Plate heat exchangers use plates that are easy to clean, and some heat exchangers also support cleaning using a CIP system. The cleaning cycle of the plate heat exchanger depends on the amount of fouling or scaling.
Plate heat exchangers are easier to maintain and operate than shell and tube heat exchangers because they are easier to disassemble and inspect. Of course, you can also easily remove the plates in a plate heat exchanger for service and maintenance, while shell and tube heat exchangers are more laborious and harder to access inside. Although product build-up or scale coating on the surface of the plate heat exchanger can reduce the heat exchange efficiency of the heat exchanger because the plate heat exchanger adopts a smaller modular design, the heat exchange efficiency of the plate heat exchanger is higher than that of the large shell and tube heat exchanger. taller and easier to clean.
Since a plate heat exchanger is designed to stack plates together, its surface area becomes compact. Compared to shell and tube heat exchangers, this stacked design reduces the footprint of plate heat exchangers, even for units with the same surface area. As shown in the image above, the compact size of the plate heat exchanger is very important for breweries where space is tight. The compact and versatile design of the plate heat exchanger means that transportation, installation, and maintenance costs are significantly reduced compared to traditional shell and tube units .
If it is possible to expand the heat transfer capacity later, a plate heat exchanger would be a good choice because you can change the heat transfer capacity by adding and removing plates. The future expansion plan needs to include the initial working size of the plate heat exchanger, the plate capacity, and the space allowance for on-site installation. There is usually no way to modify the capacity of shell and tube heat exchangers. If the heat transfer capacity needs to be expanded, only larger shell and tube heat exchangers can be replaced or added.
Having a lower cost outlay is always a key factor in the decision-making process. Plate heat exchangers are the lowest cost option because they can achieve high heat transfer coefficients and provide the most efficient heat transfer with the smallest surface area. In addition, the maintenance cost of plate heat exchangers is also very low, especially when compared to scraped surface heat exchangers. Maintenance costs for plate heat exchangers are mainly spent on replacing the gaskets and sometimes the plates.
The close-to-temperature approach means that the cold fluid can be heated to a temperature very close to the temperature of the hot fluid, and allows for more regeneration and energy recovery, making plate heat exchangers a good choice. Small temperature differences between product and medium can prevent burnout of products with moderate to high sugar or protein content.
In addition to capital expenditures for the purchase of equipment, capital costs should also include transportation, handling, installation, and maintenance costs over the life of the equipment. Plate heat exchangers weigh about 1/16 the weight of shell and tube heat exchangers and occupy only 1/10 of the footprint, which means immediate savings in shipping, handling, and installation costs. In addition, the plate heat exchanger can be assembled and disassembled on site.
Plate heat exchangers can accommodate many types of viscosities.
For viscous products, plate heat exchangers require the correct choice of plate type.
For products with particles, plate heat exchangers require special plates with ground contact points and/or wider gaps.
If your plate heat exchanger has difficulty handling viscous products, it is usually because the plate heat exchanger was designed with very low viscosity fluids in mind, but was chosen to handle highly viscous fluids. Plate heat exchangers can replace standard gap (3-5mm) chevron plates with wide flow plates for fine particles (same gap but fewer contact points than chevron plates) or wide gap (5-8mm) plates so that they can handle larger particles and higher viscosity fluids.
|Average Gap||Particle Size||Fiber Length||Pulp (%)||Viscosity CPS|
|Typical Industrial Plate||2.4-3.95mm||Dia 0.5mm||1mm||2||2500|
|Typical Sanitary Plate||3.95mm||Dia 0.5mm||1mm||3||5000|
|Low Contact Point Plate||Up to 8mm||Dia 0.5mm||5mm||7||1000|