Waste heat boiler calculation
Thread Content
There is an existing old waste heat boiler; the designed inlet gas temperature was 220 degrees, the outlet gas temperature was 180 degrees, and it produced steam at 0.5 MPa； I now want to raise the outlet temperature to 200 degrees; I’m not sure how much MPa of steam will be produced How to calculate it?
Reply 1# huaandhua: One scenario is that 0.5MPA of steam is still produced, but the output will decrease by 50%. The reason is that you originally used a temperature difference of 220→180, which is 40 degrees, while now the temperature difference is only 20 degrees. In the second scenario, since the outlet temperature increases to 200, the steam pressure can also increase; the saturated temperature of the steam can be around 170 degrees. You can look up the corresponding pressure for this value, but the amount of steam remains halved.
The temperature difference is too small, so the heat transfer coefficient is low, and as a result, less heat is transferred. Agree with the person above.
The calculation given on the 2F page is too rough; it’s acceptable for rough estimates, but in reality, the enthalpy of steam does not change linearly. Related to pressure, temperature, and dryness