The separation of n-butane and isobutane in the isomerization deisobutanization column, as well as the changes in column top temperature and pressure and the operating conditions.
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Experts, during the operation of the isobutane separation tower, when the steam flow rate remains constant, the temperatures at the bottom of the tower, on the side streams, and at the sensitive plate increase. The temperature and pressure at the top of the tower also rise in a corresponding manner. It seems that there is an increase in heavy components and a decrease in light components within the tower, resulting in a decline in the purity of isobutane at the top. At the same time, the liquid level in the reflux tank is decreasing. What actions should be taken to stabilize the temperatures and pressures within the tower, while maintaining the liquid level in the reflux tank, the purity of the isobutane product, and the desired output volume? A beginner in the chemical industry is confused and urgently needs help! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! Thank you. C5 is collected at the bottom of the tower, n-butane is taken from the side stream, and isobutane is obtained from the top of the tower
The saturated vapor pressures of isobutane and n-butane: for the separation tower we designed for isobutane, the operating conditions are a pressure at the top of the tower of 0.65 MPAG and a temperature of 54°C; the purity of isobutane at the top of the tower is 90%, while that of n-butane is 7.54%. There is also some non-condensable gas such as propane. In the situation you described, with the increase in temperature and pressure at the top of the tower, it seems that too much n-butane has been vaporized; as a result, the content of heavier components at the top of the tower is high while the content of lighter components is low. To improve the purity of the light components at the tower top, increasing the reflux to dilute the composition of the material at that level was not the right approach. The liquid level in the tower top reflux tank can be controlled manually; it is sufficient to maintain an appropriate flow rate and liquid level. For now, the key is still to lower the temperature so that the heavier components can settle. It’s an immature idea; let’s discuss any objections!
Reduce steam flow, increase reflux, and lower the temperature
Thank you {:3_57:}
What if the liquid level in the return tank is insufficient?
The isobutane removal tower itself consumes a lot of energy; increasing the reflux helps to suppress the level of n-butane
The key points are the control of the reflux temperature and the top and bottom temperatures of the tower; the reflux ratio is a fixed value, and the bottom reboiler is also a factor that needs to be taken into account