How To Select The Right Tube And Fin Heat Exchanger for Steam Generators?

How to Select the Right Tube and Fin Heat Exchanger for Steam Generators?

The selection of a suitable tube-and-fin heat exchanger for a steam generator requires the consideration of a number of technical and economic factors.

Technical parameters

Heat load: Based on the steam production of the steam generator, steam parameters (pressure, temperature) and the required heat transfer, the heat load to be borne by the tube-and-fin heat exchanger is calculated. Generally speaking, the larger the heat load, the larger the required heat exchanger size and heat transfer area.

Flow rate and flow rate: Consider the steam flow rate of the steam generator as well as the flow rate of other relevant fluids (such as cooling medium) to ensure that the channel size and structure of the tube and fin heat exchanger can meet the requirements of the fluid flow rate, so that the fluid in the heat exchanger to maintain a suitable flow rate. Appropriate flow rate can ensure good heat transfer effect, but also to avoid excessive pressure loss and wear on the pipe scouring.

Working pressure and temperature: steam generators are usually run at a certain pressure and temperature, tube and fin heat exchanger must be able to withstand the working pressure and temperature of the steam generator, and under the conditions of good performance and stability. The material and design pressure level of the heat exchanger should be selected according to the maximum working pressure and temperature of the steam generator to ensure that there is sufficient safety margin.

Media characteristics: Analyze the purity, presence of impurities, corrosiveness, and other characteristics of the steam, as well as the nature of other fluids that may come into contact with the heat exchanger. If the steam or other fluids are corrosive, it is necessary to select corrosion-resistant materials to manufacture the tube and fin heat exchanger, such as stainless steel, copper alloy.

Structural design

Tube type and fin form: common tube types are light tube, threaded tube, corrugated tube, etc. The heat transfer performance and resistance characteristics of different tube types are different. Threaded tube and corrugated tube can enhance the fluid disturbance and improve the heat transfer coefficient, but the pressure loss may be larger. There are also various types of fins, such as flat fins, corrugated fins, serrated fins, etc. Corrugated fins and serrated fins can increase the heat transfer area and improve the heat transfer efficiency, but the manufacturing process is relatively complex. According to the specific heat transfer requirements and flow characteristics to select the appropriate type of tube and fin form.

Arrangement: tube-fin heat exchanger in the arrangement of the tube with the row and fork row of two kinds. Fork row of heat transfer effect is generally better than the smooth row, but the flow resistance is relatively large. In the case of space allows and high requirements for heat transfer, can give priority to the fork row; if the flow resistance requirements are more stringent, then you can choose the smooth row.

Compactness: Considering the size of the installation space, choose the tube and fin heat exchanger with compact structure and large heat transfer area per unit volume to make full use of the limited space and improve the overall performance of the steam generator.

Material selection

Metal Material: For high temperature and high pressure steam environment, the commonly used metal materials are carbon steel, stainless steel, copper and copper alloy. Carbon steel has high strength and low cost, suitable for non-corrosive media and temperature and pressure are not too high occasions; stainless steel has good corrosion resistance and high temperature performance, often used to deal with corrosive steam or high-temperature steam; copper and copper alloys have excellent thermal conductivity, suitable for heat transfer efficiency requirements of the occasion, but the cost is relatively high.

Non-metallic materials: in some special circumstances, such as the steam purity requirements are very high, the need to avoid metal ion pollution, or the medium has a strong corrosive, you can consider the use of non-metallic materials of the tube and fin heat exchanger, such as polytetrafluoroethylene, ceramics. Non-metallic materials have good corrosion resistance and chemical stability, but generally lower strength, the use of temperature and pressure range is limited.