A batch chemical plant is to be used to produce four chemical products (A, B, C, and D) using the same equipment and in the same order, that is, using a flowshop plant. The times for each product in each piece of equipment are shown in Table P3.21.

Market demands for these products require that the ratio of A to B to C to D is 4:2:1:2. Therefore, 2_nB = 2_nD = 4_nA = n . For this batch plant, answer the following questions:

• In an operating period of 720 h how many batches of A, B, C, and D can be made using 4 single-product campaigns? (AAA…, BBBBBB…, CCCCCC…, DDDDD…) You may assume that the limiting cycle time (for large numbers of batches) applies.
• Using multiple product batch campaigns with unlimited intermediate storage, how many batches of A, B, C, and D can be made?
• How would the answer to Part (a) change if the number of batches of A were twice those of B, C, and D (i.e., A:B:C:D = 2:1:1:1)?
• For Part (a), if the required production over the 720 h of operation for product B was 30,000 kg or 27.5 m³ of product, what volume of intermediate storage would be required to ensure that a constant supply of B could be maintained over the 720 h operation?

Transcribed Image Text:

Table P3.21 Equipment Processing Times for Problem 3.21 Unit Op/Product HeatingReaction/MixingFiltration ABCD с 2.0 1.5 2.5 1.0 5.0 3.5 2.0 3.5 2.0 1.5 0.5 2.0 Distillation Crystallization 2.0 1.5 2.5 3.5 4.5 5.0 3.0 3.5