Pseudo-fresh feeds

In a chemical reactor, components in the inlet streams are consumed and new components, not necessarily in the inlet streams, are formed. The components formed cannot be shown as split-fractions of the inlet flows and must therefore be shown as pseudo fresh-feeds. 

In some processes, a component may be recycled around two or more units in a closed loop. For example, the solvent in an absorption or liquid extraction process will normally be recovered by distillation and recycled. In this situation it will be necessary to introduce the solvent as a pseudo fresh-feed and the to remove it from the recycle loop by introducing a dummy stream divider, purging one stream. 

Conversion is not usually very dependent on the concentration of any inert components. The pseudo fresh feeds of the products formed in the reactor can be calculated from the specified, or estimated, yields for the process. 

FOR EACH COMPONENT, DRAW UP A TABLE OF THE FRESH FEEDS INTO EACH UNIT. REMEMBER ANY PSEUDO FRESH FEEDS FOR REACTORS "... 

---