Appropriate pressure for Aspen simulation of ethylene glycol diethylene glycol separation
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Here, the Aspen simulation uses the Wilson equation; whereas when the DSTwu simulation is used, at low pressure levels, Aspen Plus reports errors, with the reflux ratio and number of theoretical plates taking negative values, and the system indicates that separation is relatively easy. What should be the separation pressure for ethylene glycol and diethylene glycol, and should it be carried out at atmospheric pressure or under reduced pressure? Since lower pressure results in a lower boiling point, could low-pressure conditions hinder the separation process? Can the Wilson equation chosen for Aspen simulation of alcohol separation be used under low-pressure conditions? At atmospheric pressure, simulation may result in failures or non-convergence; how should this be handled? (Does not converge after more than 25 iterations)
This is the feed stream; a suitable pressure needs to be determined
Under normal circumstances, changes in pressure do not result in significant changes in relative volatility. The pressure in a distillation column is mostly determined by the corresponding temperature; for example, high-boiling substances may require reduced pressure to ensure that the temperature of the heating medium is sufficient, while low-boiling substances need increased pressure so that circulating water can be used as the cooling medium. Heat-sensitive substances may require low pressure, and so on. Of course, there are also cases where pressure changes result in significant variations in relative volatility, but such cases are not common.