Reactor with Recycle
Mass balances are demonstrated for a reactor system. Pure A is fed to the system and two parallel reactions take place in the reactor:

A → B (desired)

A → C (undesired)

A separation unit after the reactor removes some of the unreacted A  and recycles it back to the feed stream. Use a slider to set the recycle ratio, which is the ratio of the recycle flow rate to the fresh feed flow rate. Set the reactor selectivity, which is the (flow rate of B) / (flow rate of C) leaving the reactor, with a slider. Set the reactor conversion, which is the percent of A entering the reactor that is consumed, with a slider. The overall conversion of A is the percent of the feed (100 mol A/hr) that is consumed. The yield is the percentage of the feed that is converted to the desired product B.  A negative flow rate of A  exiting the system indicates an impossible combination of reaction selectivity and reactor conversion.

Download the CDF file to view the simulation using the free Wolfram CDF player.