91��Ʒ���ϳԹ�

In process chemistry, batch failure is an inconvenient truth that we all learn to cope with. No matter how robust a process is, at some point in the lifetime of a production campaign batch failure is likely to occur. Unfortunately, we can't trace time back and situate ourselves at a chronological time before the batch failed. In batch manufacturing, the state of a reactor (i.e, the reagent to product distribution ratio) of the present cannot be set back to a past clock time. Let's consider an example.

Let's imagine a batch process that uses reagent red to give product blue at 7'o clock as shown in Fig 1. By 8'o clock, most of the red reagent has converted into the blue product. The situation becomes interesting if the product is not fished out of the batch vessel at the 8'o clock mark. By 9, a byproduct (shown in black) starts to form. Unfortunately, if we are at the 9'o clock mark, we can't take the reactor 'back to the future' and get back all good product of the 8'o clock mark.