This example will highlight the radial effects in a tubular reactor that up till now been neglected to simplify the calculations. Also, the effects of parameters such as inlet temperature and flow rate are investigated. These effects can readily be studied using a the software program COMSOL Multiphysics.
This example is based on Example 8-8 in the textbook and in that example, propylene oxide reacts with water to form propylene glycol. In 1997, 800 million pounds of propylene glycol was produced, equaling a value of approximately $536 million.
The hydrolysis of propylene oxide takes place readily at room temperature when catalyzed by sulfuric acid.
This exothermic reaction is approximated to a 1st order reaction given that the reaction takes place in an excess of water.
Since we are to investigate the effects of radial influences in a tubular rector, the CSTR from Example 8-8 has been replaced by a PFR. The length and diameter of the tubular reactor used in this example are 1 and 0.2 m, respectively.
In example 8-8 one important constraint on the operation is mentioned. Propylene oxide is a rather low boiling substance, therefore the operation temperature may not exceed 325 K or too much propylene oxide will be lost by vaporization. This is not a problem when using a tubular reactor however. A slight pressure can easily be added to prevent a temperature rise and a loss of reactant. Still, calculations here have been performed at an atmospheric pressure resulting in temperatures higher than the recommended temperature.
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