Increasing the number of openings in the secondary steam pipes for temperature and pressure reduction enhances the heating effect on the deaerator tubes
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I would like to make openings in the secondary steam pipe for temperature and pressure reduction in order to add heating pipes for the deaerator. The specific details are as follows: 1. The secondary steam pipe has a diameter of DN325*10; its parameters are pressure of 1.2 MPa, temperature of 300 degrees, and material of Q235. 2. For the heating source of the deaerator, the required steam flow is 5–8 t/h, with a pressure of 0.5 MPa and a temperature of 155 degrees. What should be the diameter of the new heating pipes? Is it okay to use #20 steel with a wall thickness of 5 mm? How to select a shut-off valve? This is my first time carrying out technical upgrades, and I would like to consult the experts. Thank you!
To answer your question, some thermodynamic calculations and pipeline design considerations are required, including but not limited to flow rate, pressure drop, heat exchange amount, etc. Please note that before actual engineering design and implementation, it is recommended to consult a professional engineer or designer for detailed design and safety checks. Below are the basic reference answers to your questions: 1. Determination of the diameter DN of the new heating pipe: The diameter of the additional deaerator heating pipe needs to be calculated based on parameters such as steam flow rate, velocity, and pressure drop. The flow rate of steam is generally kept within the range of 20–40 meters per second. Excessively high flow rates will lead to increased pressure drop and wear in the pipes, while excessively low flow rates will reduce the efficiency of heat exchange. Therefore, it is recommended to use the general formulas and engineering tables for steam pipeline design to determine the diameter of new pipelines. If you lack experience in this area, please consult relevant professionals. 2. Newly added heat pipe material and wall thickness: The #20 steel you intend to use is a commonly used steel for boilers and pressure vessels, featuring excellent high-temperature and pressure resistance. A wall thickness of 5 mm may be acceptable, but it is necessary to carry out calculations based on the specific design pressure, temperature, and pipe diameter, in accordance with relevant **standards (such as GB/T 3087-2008 \"Seamless Steel Tubes for Low and Medium Pressure Boilers\") and pressure vessel regulations. When determining the material and wall thickness, factors such as corrosion margin and welding process also need to be considered. 3. Selection of stop valves: The selection of stop valves requires consideration of factors such as the working medium (steam in this case), operating pressure, operating temperature, valve diameter, and connection method. Generally, the valve material should be compatible with the pipe material, and a model capable of withstanding the design pressure and temperature should be selected. It is also necessary to consider the operating method of the valve (manual, electric, pneumatic, etc.) as well as whether accessories are required (such as solenoid valves, limit switches, etc.). The most important thing is to ensure that the valve selection meets safety, environmental protection, and energy efficiency standards. It is reiterated that the above are only basic guidelines; before proceeding with actual implementation, it is essential to consult qualified professionals for detailed design and to follow local regulations and standards. Safety is the top priority in technical renovation projects; therefore, it is essential to ensure that all design work, material selection, and installation processes meet the highest safety standards. .