How to determine the top temperature of a distillation column
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In actual production, apart from judging based on the quality of the crude gasoline product, what other methods are there to determine whether the top temperature of the distillation tower is appropriate?
In fact, under many similar conditions, the control requirements can be met by using other measurement parameters.
As long as the bottom and middle temperatures remain stable, fluctuations of 1°C to 2°C in the top temperature should not be a problem； Efforts also need to be made in terms of operational experience. The focus should still be on the test results, and product quality should be adjusted in a timely manner based on those results.
When the operation is stable, once the feed load and composition to the tower, as well as the top pressure and reflux ratio, are determined, the top temperature is also fixed – namely, the equilibrium temperature under the given top pressure and gas-liquid phase compositions. If there are significant fluctuations in temperature and the quality of the product at the top of the tower, it is usually due to inadequate control strategies for the thermal balance and material balance of the tower.
Percentage of product materials: the output of crude gasoline is fixed, and cold reflux is used to maintain a stable liquid level in the cold reflux tank at the top of the tower.
To save energy and reduce consumption, we do not allow cold reflux; instead, we use top circulation to adjust the temperature at the top of the distillation tower
The partial pressures of various components in the principles of chemical engineering
The view on the 9th floor is the same as that of our company. Another point is that, while ensuring a high dry point for the crude gasoline, the top temperature should be kept above 100 degrees to prevent water from being carried in by the overhead oil flow and to avoid salt buildup on the tray surfaces.