Block and Information Flow Diagram

Unit operations such as mixers, separators, reactors, fuel cell, distillation columns, and heat exchangers are usually denoted by a simple block or rectangle. 

Groups of unit operations may be noted by a single block or rectangle. 

Process or information flow streams flowing into and out of the blocks are represented by neatly drawn straight lines. These lines should either be horizontal or vertical. 

The direction of flow of each of the process flow streams must be clearly indicated by arrows. 

Flow streams should be numbered sequentially in a logical order. 

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