Temperature control method for 3.5MPa steam system
Thread Content
The waste heat boiler of the catalytic unit generates 3.5 MPa steam for use in the catalytic turbine, with external pipeline networks providing supplementary steam. Currently, due to the plant operating at full capacity, 3.5MPa steam requires exactly enough supply, or a slight additional amount of 1–2 T. As a result, the steam temperature in the external steam pipeline dropped, reaching as low as around 260°C. If an accident occurs (such as a sudden drop in the amount of steam generated), will it affect the operation of the turbine? Has everyone encountered this phenomenon? How to address the temperature drop?
We have encountered this situation before: the medium-pressure steam generated by our catalytic process and that produced by the waste heat power plant were previously connected to each other, allowing them to complement each other in case there were issues with the steam supply on one side. However, due to the fact that the connecting pipeline was several hundred meters long, it often caused the temperature at the turbine inlet to rise to 360 degrees. On one occasion, water in the steam led to the shutdown of the compressor. After further discussion and analysis, it was decided that this pipeline should be connected only to supply steam to the catalytic process during startup, and not connected at other times. Now, there are hardly any cases of low temperatures or the presence of water in the steam!
It is necessary to ensure that the steam in the public systems remains in a state of flow at all times, while monitoring pressure and temperature via the DCS, and maintaining constant communication and coordination with the power plant and the dispatch team
A steam separator should be installed before entering the catalytic cracking unit; this makes things safer~~~ Additionally, external steam should not go directly to the turbine inlet, so there shouldn’t be any problems~~~ It’s important to ensure that the make-up steam pipeline has sufficient flowability, in order to avoid the accumulation of large amounts of condensed water~~~
Increase the amount of supplementary steam to 4 T/h and see the effect. Additionally, monitor the steam temperature on the DCS screen; if it is below 360°C, make adjustments to the drain system promptly to prevent low temperatures from causing damage to the turbine.