Innovative concept in designing of multi-tubular fixed bed catalytic reactor

If we use beds in series type fixed bed reactor, we need to take reactants/(Product +Reactants) out and exchange heat in heat exchanger & then to take back to the reactor & sent them to the next bed of catalyst. Here, we need to use heat exchanger for which capital & operating cost is required during designing of reactor for manufacturing of ethyl benzene from benzene & ethylene, we decided to use multi-tubular reactor in place of fixed beds in series. So, that capital & operating cost can be saved for heat exchanger. When we did calculations length of tubes required was much more than the height of the bed of catalyst. So, for better heat transfer we distributed total length of the bed of catalyst into three beds of catalyst in tubes only.