A batch process is operated with the following sequence. The feed to the batch process consists of a solution of 500 L of ethanol with 120 mole of A and 120 mole of B. If the temperature of the solution is sufficient, A and B will react to form P (the desired product): A (eth) + B (eth) → P (s) DHreact = − 250 kJ/mol (1) Note that the product P is sparingly soluble in ethanol, which helps facilitate its removal from the reaction solution. It can be assumed that the reaction rate is first-order in both the concentration of A (cA) and B (cB), and so second-order overall: (2) The batch process consists of the following FOUR steps: Initially, the tank is empty. Fill tank with solution (ethanol/A/B).Increase temperature of the feed from 20°C to 50°C (1 hour) Reaction takes place isothermally at 50°C (4 hours, to give conversion of 50%) Filtration of reaction solution to give product P (2 hours) Drying with hot nitrogen gas followed by the removal of powder product (3 hours) It can be assumed that the heating time for Stage 1 (t1) is proportional to the change in temperature (which is 30°C in the case above). This would assume a constant-power heater. The heat capacity of the solution can be taken to be 500 kJ/K. The batch process does not include any heat integration. List the various heat loads and outline a strategy to allow for the inclusion of a simple HEN with this single equipment unit.
A batch process is operated with the following sequence. The feed to the batch process consists of a solution of 500 L of ethanol with 120 mole of A and 120 mole of B. If the temperature of the solution is sufficient, A and B will react to form P (the desired product):
A (eth) + B (eth) → P (s) DHreact = − 250 kJ/mol (1)
Note that the product P is sparingly soluble in ethanol, which helps facilitate its removal from the reaction solution. It can be assumed that the reaction rate is first-order in both the concentration of A (cA) and B (cB), and so second-order overall:
(2)
The batch process consists of the following FOUR steps:
Initially, the tank is empty.
- Fill tank with solution (ethanol/A/B).Increase temperature of the feed from 20°C to 50°C (1 hour)
- Reaction takes place isothermally at 50°C (4 hours, to give conversion of 50%)
- Filtration of reaction solution to give product P (2 hours)
- Drying with hot nitrogen gas followed by the removal of powder product (3 hours)
It can be assumed that the heating time for Stage 1 (t1) is proportional to the change in temperature (which is 30°C in the case above). This would assume a constant-power heater. The heat capacity of the solution can be taken to be 500 kJ/K.
The batch process does not include any heat integration.
List the various heat loads and outline a strategy to allow for the inclusion of a simple HEN with this single equipment unit.
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