Should I treat the side reaction as a 3rd reaction? What I mean is, what would be the overall rate of reaction equation?

I am not sure if I am asking the right question.

I just need to get the space time value...

Urea is being produced from ammonia as part of the process of producing nanofertilizers. Design a continuously stirred tank reactor with a capacity of 60,000kg/hr operating for 300 days per year. Assume a urea conversion of 95%. The output must contain 34% urea. Show your complete solution. The reaction mechanism of converting ammonia to urea with a corresponding side reaction is as follows: Reaction 1: CO2+2NH3NH2COONH4 Reaction 2: NH2COONH4NH2CONH2+H2O Side Reaction: 2NH2CONH2NH2CONHCONH2+NH3