Study 21.3 Interaction of Design and Control in the MCB Separation Process

CASE STUDY 21.3 Interaction of Design and Control in the MCB Separation Process 

Step 1 Set objectives. To achieve the primary control objective, the production level is maintained by flow control of the feed stream using valve V-1. 

Step 3 Establish energy management system. The steam valve, V-2, is used to control the flash feed temperature. Furthermore, the temperature of the recycle and bottoms product streams is con-tolled by adjusting the coolant valve, V-10. 

Step 4. Set the production rate. As stated previously, the feed valve, V-1, is assigned to a flow controller, whose setpoint regulates the production rate. 

Step 5. Control product quality and meet safety, environmental, and operational constraints. The pressure in V-100 is controlled by adjusting the flow rate of the vapor stream using valve V-3. Pressure regulation in T-101 is carried out by adjusting V-5, the coolant valve to the condenser E-101. Since both of the products from T-101 are required to meet specifications, the LV configuration is implemented, noting that the reflux ratio in the column is less than five. Thus, the reflux valve, V-7, is adjusted to control the distillate composition, and the reboiler steam valve, V-9, is used to regulate the bottoms composition. 

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