Which description best defines a batch chemical process?

Which description best defines a batch chemical process?

• A. The feed is added periodically, and product is removed after processing.
• B. The feed is added continuously and product removed continuously.
• C. No mass crosses the system boundaries between feed addition and product removal.
• D. The system maintains a fixed volume with continuous input.

Answer: (C)

In a batch chemical process, operation is discrete and time-bounded: you load the reactor, let the reaction proceed, and then remove the product. During the processing interval, the system is effectively closed to mass transfer, so no feed enters and no product leaves while the batch is underway. The statement that no mass crosses the system boundaries between when you add feed and when you remove product captures this defining behavior. The other descriptions describe continuous or semi-continuous operation: feed and product moving in and out continuously, or continuous input with a constant volume, which are not characteristic of a pure batch process.

In a batch chemical process, operation is discrete and time-bounded: you load the reactor, let the reaction proceed, and then remove the product. During the processing interval, the system is effectively closed to mass transfer, so no feed enters and no product leaves while the batch is underway. The statement that no mass crosses the system boundaries between when you add feed and when you remove product captures this defining behavior.

The other descriptions describe continuous or semi-continuous operation: feed and product moving in and out continuously, or continuous input with a constant volume, which are not characteristic of a pure batch process.