Questions about distillation
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1. Conditions: Multi-component distillation, constant pressure. Mixtures with several different component concentrations can all correspond to the same bubble point temperature. And during the production process, under constant pressure conditions, is it okay to use temperature as an indicator of concentration? ； 2. Dry benzene is extracted; to strictly control the water content, side extraction is generally used. But I remember the isopropylbenzene unit in phenol; in the side stream extraction of benzene, the benzene content was 99.9% (I think that’s the figure; I’ll provide the exact value after checking it). It’s incomprehensible that pure components are obtained from the side streams of a distillation tower. I’d like to ask everyone for advice
Regarding the issue in point 2, it’s something like this: a tower with multiple feed streams can enable the extraction of pure components through side streams, which is equivalent to stacking several towers on top of each other, with the bottom of the upper tower coinciding with the top of the lower tower; the components are the same, the concentrations are the same, and it may be a single component. I hope for your guidance
1. The equilibrium in a distillation column refers to equilibrium throughout the entire column, not just at the top of the column. It is only at the top of the column that a situation can arise where various mixtures with different component concentrations can all correspond to the same bubble point temperature. ”In fact, you can start by calculating based on the balance at the feed plate, using the phase ratio; one temperature corresponds to only one composition. 2. Single-stream feeding can also be used for side-stream extraction, and there will be enrichment zones – you can run a simulation to see this clearly