Cascade control in distillation operations
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Dear colleagues: Since the distillation steam in our company is of low quality, generated by back-pressure units, and fluctuations in the steam supply across the entire network occur due to shutdowns caused by ash accumulation after gas production, this poses many difficulties for the distillation process. Although there is a steam buffer tank in front of each column’s reboiler and the valves leading to this tank are under automatic control, the fluctuations remain significant. We are considering replacing the valves in front of each column’s reboiler with cascade control systems (which are currently used to control the temperature of the column bottoms). Would this approach result in a more significant reduction in fluctuations?
It’s not clear what kind of cascade control you are using, and what is the automatic control mechanism for the buffer tank? It must be stress, right? If, in order to control the temperature at the bottom of the tower, the steam pressure and flow rate are used in a cascade configuration, that is feasible; we do the same here as well. It’s just that the steam fluctuations can’t be too large; otherwise, it still won’t work...
The ash under one furnace shouldn’t have such a big impact, right? If that doesn’t work, then modify the steam pipeline network. The turbine extraction should be relatively stable, with a dual-reduction backup system in place to compensate for pressure changes at any time. The steam used for gas production is usually used for internal purposes. Do not force it to connect to the steam pipeline network. Pipe network pressure fluctuations – it works extremely well no matter what it’s connected to. Reactor bottom temperature, steam flow rate – try connecting them together