The Application of Finned Tube Heat Exchangers in Granulation enterprises

The application of finned tube heat exchangers in granulator manufacturing enterprises mainly lies in their efficient heat transfer, compact structure and ability to adapt to high-temperature and high-pressure environments, especially playing an important role in the melt cooling and waste heat recovery of exhaust gas in the plastic granulation process. The following is an analysis of its production process application and typical cases:

1. Application of production processes

1.1. Melt cooling system

When the granulator extrudes plastic pellets, the melt needs to be rapidly cooled and set. Finned tube heat exchangers cool the melt pipes with water or air, and use fins to increase the heat dissipation area and accelerate heat transfer. High-frequency welded spiral finned tubes have become the first choice due to their high welding rate (up to 95%) and strong pressure resistance (tensile strength 200MPa).

1.1.1. Case: Some enterprises use steel high-frequency welded finned tubes, with cooling water flowing through the inside and forced convection heat dissipation on the outside. The cooling efficiency is more than 8 times higher than that of smooth tubes.

1.2. Recovery of waste heat from exhaust gas

The high-temperature waste gas produced during the granulation process can recover heat energy through finned tube heat exchangers and be used for preheating raw materials or heating the workshop. For instance, spiral finned tubes reduce ash accumulation through flue gas diversion design and are suitable for exhaust gas environments containing dust.

1.2.1. Technical Features: The three-roll oblique rolled integral finned tube has no contact thermal resistance and higher heat transfer efficiency, making it suitable for high-temperature (>500℃) waste gas treatment.

1.3. Hydraulic oil cooling

The hydraulic system of the granulator is prone to a decrease in efficiency due to high temperatures. The finned tube heat exchanger stabilizes the oil temperature through gas-liquid heat exchange. Embedded spiral finned tubes or bimetallic extruded finned tubes (such as aluminum-clad steel) are often used in such scenarios due to their corrosion resistance and lightweight characteristics.

2. Typical cases

2.1. Application of High-frequency Welded Finned Tubes in Plastic Granulation Cooling Towers

2.1.1. Process: The SRZ-5-5Z type finned tube heat exchanger is adopted, with a fin spacing of 4mm and a height of 55mm. The anti-corrosion performance is enhanced through hot-dip galvanizing surface treatment.

2.1.2. Effect: The heat exchange area is 8 times that of the smooth tube, achieving remarkable water-saving effects. It is particularly suitable for open cooling systems in high-humidity areas in the south.

2.2. Practice of Multi-material Finned Tubes in Energy-saving Transformation

2.2.1. Case: A certain enterprise adopted the "Joining by forming" technology developed by the Polytechnic University of Turin to combine aluminum fins with stainless steel base tubes to manufacture multi-material heat exchangers. Experiments show that its efficiency is increased by 100% compared with traditional steel heat exchangers, and its weight is reduced by 30%.

2.3. Application of Wear-resistant Finned Tubes in the Recovery of Granulation Waste Gas

2.3.1. Design: The integral sandar-shaped finned tube avoids local erosion by guiding the flue gas, and its wear life is twice that of the smooth tube (7-8 years), making it suitable for the treatment of waste gas containing glass fiber reinforced plastics.

3. Key points of production and maintenance

3.1. Selection of manufacturing processes

3.1.1. High-frequency welding: Suitable for mass production, but the fins are relatively thick (≥0.8mm), and the heat exchange efficiency is slightly lower.

3.1.2. Extrusion molding: The aluminum fins are closely combined with the base tube, with low thermal resistance, but the cost is relatively high.

3.2. Maintenance Requirements

3.2.1. Regularly chemically clean the scale and check if the fins are deformed (manually straighten the aluminum fins).

3.2.2. Avoid corrosive media. For instance, acidic waste gas should be made of stainless steel.

4. Future Trends

4.1. New materials: For instance, the corrosion-resistant composite finned tubes developed by Shandong Beichen Company, which are coated with epoxy resin, are suitable for chemical granulation environments.

4.2. Intelligence: Integrate temperature sensors and automatic regulation systems to optimize heat exchange efficiency.

Through the above applications, the finned tube heat exchanger has significantly enhanced the energy efficiency and stability of the granulator. In the future, with the innovation of materials and processes, its role will be further expanded.

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