Problems of steam temperature and pressure reduction
Thread Content
Can steam at 1.6 MPa and 260°C be directly fed into the heat exchanger? Without temperature and pressure reduction
Sure, those with 9.5MPA are all fine
What kind of heat exchanger? Steel or graphite? Graphite ones are more dangerous
It will affect the heat exchange efficiency, as there is a heat-insulating layer on the surface where steam exchange occurs.
Steam at 1.6 MPa and 260°C is superheated steam, with a superheat of over 50 degrees. The heat transfer efficiency is very low when using superheated steam for heat exchange, and it can also lead to the formation of dry walls near the shell or tube sheet of the heat exchanger, resulting in scaling and overheating of the tube walls, which in turn causes failure. Therefore, before heat exchange, the superheated steam must be cooled and depressurized to saturated steam. Also, even after temperature and pressure reduction, a steam pressure of 1.6 MPa is still too high, unless the material needs to be heated to a very high temperature. While meeting the heating temperature requirements, the steam pressure should be as low as possible, which will result in significant energy savings. “The WeChat official account \"Fured Steam Energy Saving\" has an article titled \"This ‘killer’ isn’t cold at all\" that discusses this topic; you can also visit the Fured Steam Energy Saving official website to view related content.
It can be used, but the effect is not good. It is generally better to reduce it to 0.5–0.7 Mpa for saturated steam entering the heat exchanger
Whether it can be installed depends on whether the heat exchanger can withstand such high pressure
The housing can handle it; there’s no problem going in. However, if the shell-side fluid is deflected by baffles, problems may occur. After the superheated steam is cooled, it gradually condenses. During the flow within the shell side, a gas-liquid two-phase flow occurs, which exerts significant stress on the heat exchange tubes; prolonged operation may lead to the risk of tube leakage
For high-pressure heaters in power plants, the inlet parameters we use are considered low; most of the steam used is superheated steam