In recent years, finned tube heat exchangers have been widely used in textile printing and dyeing, wood drying, grain and oil food drying, coating and baking paint dehumidification, power and petrochemical industries, and have achieved satisfactory results. Due to different process conditions and requirements, it is necessary to design various fin-tube heat exchangers that are most realistic.
The following principles should be followed when designing finned tube heat exchangers;
1; In the case of a given process temperature and flow rate, the outlet must meet the temperature requirements.
2; Reasonable heat exchange area, proper design surplus.
3; On the premise of meeting the pressure loss requirements, try to increase the heat transfer coefficient, reduce metal consumption, and reduce equipment costs.
4; The choice of finned tube material takes into account fluid corrosion, wear, pressure, temperature and other requirements.
5; For temperature changes, stress relief methods may occur.
6; Strength calculation of tube sheet, tube box and components.
7; Installation form and the restrictive requirements for the length, width and thickness of the external dimensions.
8; Consideration of equipment accessories. Including condensate removal methods, maintenance manholes, liquid level switches, reserved holes for temperature control electric thermocouples, pressure gauges and exhaust holes, exhaust holes, etc.
9; The feasibility of manufacturing and welding processes. Convenience of later maintenance, installation and transportation.
10; Cost-effectiveness of finned tube heat exchanger equipment investment.
The above factors will restrict and influence each other. In the case of different processes, the focus will be different, so the importance of various factors should be considered in the design of fin tube heat exchangers. Usually the focus is divided into three categories;
1. Heat exchange effect. The finned tube heat exchanger that does not achieve the heat exchange effect is equivalent to a pile of scrap iron, or the temperature is lower than the design requirement, which will affect the production efficiency of the product, and if it is serious, it will affect the quality of the product.
Second; the safety and reliability of equipment operation, if the heat exchanger has a problem, the loss of production shutdown and the loss of pollution to the product may be far greater than the equipment investment.
Three; The balance of the comprehensive investment cost and operating cost of the equipment. For example, if the cost of increasing the wind pressure is used to reduce the heat exchange area, it is not worth the loss. Increasing the wind pressure will increase the power consumption of the motor, and the cost of long-term operation will far exceed the equipment investment.