The work contributes to the research field of population balances mainly aggregation and breakage mechanisms. The research comprises of - Along with one dimensional scheme, multidimensional number based numerical scheme has been proposed to solve aggregation PBE.- Multidimensional mass based numerical scheme is introduced to solve aggregation PBE.- Analytical solution for breakage as well as aggregation kernels.- Modeling and simulation of top-sprayed fluidised bed granulator.