Input for the batch reactor Rbatch in Aspen
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What is simulated here is a semi-continuous reaction: one stream involves a single batch feed of 200 kg, while another stream has a continuous feed at a rate of 300 kg/h for a duration of 2 hours. The required reaction time is 4 hours. How should these values be entered in the stop criteria and operation times fields? On page P148 of Sun Lanyi’s book, the reaction time specified in the stop criteria is 1.5 hours, while the maximum calculation time allowed in the operation times field is set at 2 hours. Since 2 hours is greater than 1.5 hours, does this make sense? Why are these values entered in this way?
For semi-continuous reactions, when modeling in Aspen using the batch reactor Rbatch, two continuous feed streams can be considered. For the first continuous feed, it can be used as the input to the batch reactor by feeding 200 kg at once, with the time parameter set to 2 hours in the Stop Criteria. For the second continuous feed, the Feed event can be enabled in the Operation tab; the flow rate should be set to 300 kg/h, and the maximum calculation time should be set to 4 hours in Operation Times to meet the requirements of this reaction. As for the example in Sun Lanyi’s book, the reaction time specified in the Stop Criteria is 1.5 hours, while the maximum calculation time set in the Operation Times is 2 hours. This is because reaction time refers only to the time required to reach a certain degree of reaction or conversion rate, rather than the time required for complete reaction. In practical operations, we need to ensure that the program can run until the reaction reaches the state of theoretical equilibrium, without having to worry about the time required for complete reaction. Therefore, when setting the stop criteria and maximum calculation time, adjustments need to be made based on the actual situation. .