Understanding a parameter of high-pressure steam
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In our high-pressure steam network, the normal control pressure is 10.79 MPa at 513 degrees. However, there is a very important parameter related to high-pressure steam, which is 6.86 MPa. 1. When shutting off air in the second-stage furnace, it is necessary to maintain the pressure in the high-pressure network at 6.86 MPa. 2. When the steam generated by the waste heat boiler is connected to the high-pressure steam network, the pressure at the outlet of that boiler must also be 6.86 MPa. 3. This value of 6.86 MPa is also a crucial parameter when constructing the steam network. My question is: since 6.86 MPa is such an important parameter, how should we understand its role in chemical production? What are the consequences of having a pressure lower than this value? Is it simply to avoid water hammer? Thank you
Firstly, a pressure of 6.86 MPa is an intermediate value within a range, rather than a specific pressure or one that would cause a mutation. Check the design of the waste heat boiler to see if it is of the double-tube type; if so, controlling the high-pressure steam at 6.86 serves to prevent backflow. When adding or removing air, controlling the pressure serves two purposes: first, to prevent backflow; second, in a two-stage furnace where there is no air, the temperature at the waste heat boiler inlet is low, resulting in a small temperature difference for heat transfer, and reducing the pressure helps improve heat transfer. The process isn’t very clear; maybe the explanation was incorrect.
Thank you for your participation; I really appreciate it. I think what you said makes sense, but after thinking about it further, I wondered whether, for users of high-pressure steam, this might be related to turbines Could too low pressure cause damage to the turbine? Please help think about this
It is mainly related to the temperature during the high-temperature shift at the end of steam heating; a temperature of around 285 degrees at a pressure of 6.86 MPa is required – it cannot be too low, otherwise the temperature at the outlet of this high-temperature shift process will not meet the specified requirements.
Under normal circumstances, the turbine should have stopped operating once the high-pressure steam is reduced to 6 MPa. What was discussed above is why it cannot be too high. If it is too low, first, as mentioned above, there are temperature limits for the reactor after waste heat removal; second, under normal high pressure conditions, the pressure should be reduced to that of the medium-pressure steam system, as maintaining a pressure difference is necessary to ensure proper flow