Oftentimes, during the design of a new process, it is required that we mix a number of streams in order to create a mixture with certain composition. This operation simulates an intelligent mixer that automatically will adjust the (bulk) flow of its input streams (up to 5) in order to meet a user-specification describing the output composition and flow. If there are n input streams to the procedure then n-1 key components and their concentration needs to be specified. The output mass (or volume) flow can be specified by the user, set by the downstream process (via a back-propagation request), or calculated based on the “known” flow of a fixed input stream. An overall mass balance, and n-1 component mass balances are solved simultaneously in order to determine the inlet stream flow rates.
Under certain circumstances, the model will fail to determine a value for the adjustable inlet streams and a warning will message will appear, explaining why the specifications set are unachievable and giving suggestions on how to remedy the situation.
● Mixture Preparation Procedure
If the equipment size option is in Design Mode and the operating throughput exceeds the maximum throughput, then, the program assumes multiple, identical units operating in parallel with an operating throughput of less than the maximum. If the equipment size option is in Rating Mode and the operating throughput exceeds the rated throughput of the step (which is equal to the rated throughput of each unit times the number of units), a warning message is displayed advising the user to increase the number of units or reduce the operating throughput.
The interface of this operation has the following tabs:
● Oper. Cond’s, see Mixture Preparation: Oper. Conds Tab
● Utilities, see Throughput Operations: Utilities Tab
● Labor, etc, see Operations Dialog: Labor etc. Tab
● Description, see Operations Dialog: Description Tab
● Batch Sheet, see Operations Dialog: Batch Sheet Tab
● Scheduling, see Operations Dialog: Scheduling Tab